An apparatus for preventing erosion of wellbore components comprises a wellscreen and a coating disposed on the wellscreen. The coating includes a metal-based coating and preferably nickel and phosphorous. The coating may also be organic-based such as phenolic resin containing ceramic or cermet. A method for fabricating an erosion and corrosion resistant wellbore component by providing the wellbore component and treating the wellbore component with erosion resistant materials. The treating step is conducted by plating the wellbore component, preferably by electroless plating. The treating step further comprises heat treatment of the wellbore component subsequent to plating. An additional step of inserting the treated wellbore component into a wellbore may also be conducted.

1. Field of the Invention
The invention relates to apparatus utilized in the production of hydrocarbons. More particularly, the invention relates to an apparatus and method for preventing erosion of wellbore components utilized in wellbores during production of hydrocarbons.
2. Description of the Background Art
When a wellbore is ready for production of hydrocarbons, wellbore components such as a wellscreen are typically inserted into the wellbore on a string of production tubing. Thereafter production fluid passes through the wellscreen and is pumped to the surface through the tubing. Wellscreen typically includes a perforated inner tube and some type of wire screen (sand screen) therearound to prevent sand and other debris from entering the tubing with the production fluid. The wellscreen, when placed downhole, forms an annular area with the wellbore.
When using a wellscreen in a wellbore, the annular area surrounding the wellscreen is often filled with gravel in a gravel packing operation. FIG. 1 is a cross sectional view of a well including a wellscreen in a wellbore with a gravel pack. Gravel packing is useful for additional filtering the production fluid, establishing a uniform flow of the production fluid along the wellscreen and preventing the collapse of the adjacent formation. FIG. 1 illustrates a formation 100, a wellbore 102 proximate the formation 100, and a casing 104 lining the wellbore 102. A production string 110 with a wellscreen 116 disposed at a lower end thereof provides a path for fluid to pass through the production string 110 to the surface of the well 122 for further processing. Perforations 106 are also formed in the casing 104 to allow production material to flow from the formation 100 into the wellbore 102.
Disposed between the production string 110 and the wellscreen 116 is a cross-over tool 112. The cross-over tool 112 comprises a central pipe 111 and a chute 118 extending outward from the central pipe 111 and into an annular area 114. Gravel 120 is dispensed in a slurry form from the surface of the well 122 and exits at the chute 118 to fill the annulus 114. A wash pipe 108 (shown with dotted lines in FIG. 1) is contained within the production string 110 and serves as a conduit for extracting the liquid from the slurry so that only the gravel 120 remains in the annulus 114.
Gravel packing is not a precise process. For example, some portion of the wellscreen may not always receive adequate gravel packing therearound and may be left exposed. The suction created by the wash pipe as it urges liquid out of the wellbore may compress the gravel, leaving the upper portion of the wellscreen exposed. The gravel may also settle over time, leaving the wellscreen partially exposed. The exposed area of the wellscreen is then subjected to high velocity production fluid containing solid materials. Such solid materials are normally trapped by the gravel thereby prevent damage the wellscreen. However, the exposed portion of the wellscreen provides a path for the solid materials to impact the wellscreen directly, causing premature erosion, corrosion and compromising the structural integrity of the wellscreen.
In response to the erosion and corrosion problems, protective coatings have been applied to the wellscreen. However, the conventional techniques typically require the coating to be sprayed onto wellscreen, which can waste the coating materials and may not adequately cover the entire screen. In addition, the spraying technique does not apply the coating evenly on the wellscreen leaving parts of the wellscreen at least partially exposed to erosion and corrosion. Further, the conventional techniques coat only the screen portion of the wellscreen, leaving the other components, like the interior base pipe, susceptible to erosion.
Therefore, there is a need for a wellscreen that is more erosion and corrosion resistant to impact by fluids containing solid materials. There is also a need for a method of protecting wellscreens from premature erosion and corrosion that can be applied efficiently and evenly and to all parts of the wellscreen for maximum protection.
The present invention generally provides an apparatus and method for preventing erosion and corrosion of wellbore components through the use of a coating applied to the component. In one aspect, the coating includes a metal-based coating and is preferably nickel and phosphorous. The coating may also be an organic-based coating such as phenolic resin containing ceramic or cermet. The coating may be applied to all parts of the wellscreen including the base pipe. In another aspect, a method for fabricating an erosion resistant wellbore component comprises providing the wellbore component and treating the wellbore component with erosion resistant materials. The treating step is conducted by plating the wellbore component, preferably by electroless plating. The treating step may further comprise heat treatment of the wellbore component subsequent to plating.

Apparatus for preventing erosion of wellbore components and method of fabricating same


A driver management unit of a management server develops non-[1:1] type association information generated in a batch association creation mode into [1:1] type association information. On the other hand, the driver management unit stores association information created in an ordinary association creation mode in a data storage unit without performing the development. Further, the driver management unit transmits a list of the association information stored in the data storage unit to a client in response to a request, and distributes a driver selected from the list to the client in such a way as to create a logical printer of a device that corresponds to the association information selected from the list for the client.

1. Field of the Invention
The present invention relates to a technique capable of associating an image forming apparatus with a printer driver and distributing a printer driver to a client apparatus.
2. Description of the Related Art
As conventionally known, a PUSH mode chiefly performed by a management server and a PULL mode chiefly performed by a client are usable as a method for causing the management server to install a driver (i.e., a device driver) suitable for a device accessible via a network to the client.
In the following description, the technical terminology "device" represents an image forming apparatus, such as a printing apparatus (e.g., a single function printer (SFP) or a multifunction peripheral (MFP)) or a scanner apparatus. Further, the technical terminology "driver" represents, for example, a printer driver capable of forming print data to cause an intended device to perform printing when a user of a client has instructed a printing operation via an application installed thereon.
For example, as discussed in Japanese Patent Application Laid-Open No. 2008-203929, in the PUSH mode, when a management server distributes a driver to a client, the management server generates a task including information about a client as distribution destination and association information correlating the driver with a corresponding device. The client executes the task to realize installation of the distributed driver.
In the PULL mode, the user of the client accesses the management server and selects an arbitrary association from an association list. Then, the user downloads related launcher software and installs an intended driver on the client.
The above-described PUSH mode and ordinary PULL mode are collectively referred to as "operation mode." Further, the method for installing a driver in the PUSH mode is referred to as "ordinary driver remote installation processing." The PULL mode is referred to as "ordinary driver download processing."
Further, the technical terminology "association" represents information including device information and driver information. The "association" conformation is, for example, [1:1], [X:1], [1:Y], and [X:Y], which represent a relationship between the number of devices and the number of drivers that are mutually associated.
Further, the technical terminology "device information" includes information, such as a printing apparatus name, a product name, a location, and an internet protocol (IP) address, usable to identify and select an arbitrary device from a plurality of devices to cause the selected device to perform printing.
Further, the technical terminology "driver information" includes information, such as a driver name, a printer name, a version, and a language (e.g., page description language (PDL) to be used), usable to identify and select an arbitrary driver from a plurality of drivers.
As described above, when the device information and the driver information are associated beforehand and if a driver is distributed to a client, it is feasible to install an appropriate driver on the client by selecting the created association without designating a device and a driver in each case.
However, according to the conventional technique, the following issue arises with respect to the operability in selecting an association that correlates the operation mode with the association conformation, as well as installation result of the driver.
In a case where the [1:Y] type association that associates one device with a plurality of drivers is developed into and displayed as [1:1] type associations, a user needs to perform a complicated operation to select <Y> pieces of associations successively. Further, in a case where the [X:1] type association that associates a plurality of devices with one driver is directly displayed to let a user select a desired one, <X> pieces of printer (logical printers) are generated on the client. As described above, according to the conventional device-driver association technique, there is room for further improvement with respect to the operability in the association selection.

Server apparatus and method for the same


The metal part is one where a carboxyl group or an amino group, or a hydroxyl group is imparted onto the surface. On the other hand, the resin part is one into which an adhesiveness modifier containing an epoxy group is blended. A process for producing a composite of metal and resin, wherein the metal part and the resin part are bonded by interaction of the carboxyl group or the amino group, or the hydroxyl group with the epoxy group.

1. Field of the Invention
The present invention relates to a process for producing a composite comprising a metal part composed of a metal and a resin part composed of a resin bonded together.
2. Related Art
In these days, there have been developed various composites where distinct materials are bonded together and characteristics of the materials are utilized. Particularly, since a composite of metal and resin has distinctness, it is considered that its use application will be further extended in future.
In the composite of metal and resin, as a method for bonding a metal and a resin, there have been proposed a method of blending an epoxy resin into a polyarylene sulfide-based resin and bonding the metal and the resin (JP-A-5-214071) and a method of forming a film of a thermally modified epoxy resin on a metal surface to bond the metal and the resin (JP-A-2004-58646). However, by these methods, a sufficient adhesiveness has not been attainable.
In addition, as a modification method of a metal surface, a method of plasma-excitation of a mixed gas of an inert gas and a reactive gas of a carbon-containing compound or a sulfur-containing compound (JP-A-6-88242) has been proposed.
Wettability of the metal surface modified by this method is improved but the adhesiveness with the resin is uncertain.

This patent is subject to a terminal disclaimer.

Process for producing composite of metal and resin


In accordance with the exemplary embodiments of the invention, as described herein, there is at least a method, apparatus, and a computer program code to receive signaling from an access node of a wireless network that uses component carrier aggregation, the signaling including an identification of a plurality of component carriers and a priority associated with individual ones of the component carriers, and select one of the component carriers to camp on when in an idle mode. Further, in accordance with the exemplary embodiments of the invention, there is transmitting signaling from an access node of a wireless network that uses component carrier aggregation, the signaling including an identification of a plurality of component carriers and a priority associated with individual ones of the component carriers, and receiving a random access channel corresponding to a component carrier selected by a user equipment in accordance with the transmitted signaling.

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
3GPP third generation partnership project
ARFCN absolute radio frequency channel number
BCH broadcast channel
BW bandwidth
CC component carrier
CN core network
DL downlink (eNB towards UE)
eNB EUTRAN Node B (evolved Node B)
EPC evolved packet core
EUTRAN evolved UTRAN (LTE)
HSPA high speed packet access
IMSI international mobile subscriber identifier
LTE long term evolution
LTE-A long term evolution advanced
MAC medium access control
MIB master information block
MM/MME mobility management/mobility management entity
Node B base station
OFDMA orthogonal frequency division multiple access
O&M operations and maintenance
PDCP packet data convergence protocol
PDSCH physical downlink shared channel
PHY physical (Layer 1)
RACH random access channel
RAN radio access network
RLC radio link control
RRC radio resource control
SC-FDMA single carrier, frequency division multiple access
SCH shared channel
SGW serving gateway
SIB system information block
SIM subscriber identity module
UE user equipment
UL uplink (UE towards eNB)
USIM universal subscriber identity module
UTRAN universal terrestrial radio access network
The specification of a communication system known as evolved UTRAN (EUTRAN, also referred to as UTRAN-LTE or as EUTRA) has been discussed within the 3GPP. As specified the DL access technique is OFDMA, and the UL access technique is SC-FDMA.
One specification of interest is 3GPP TS 36.300, V8.7.0 (2008-12), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (EUTRA) and Evolved Universal Terrestrial Access Network (EUTRAN); Overall description; Stage 2 (Release 8). This system may be referred to for convenience as LTE Rel-8, or simply as Rel-8. In general, the set of specifications given generally as 3GPP TS 36.xyz (e.g., 36.211, 36.311, 36.312, etc.) may be seen as describing the Release 8 LTE system. More recently, Release 9 versions of at least some of these specifications have been published.
FIG. 1A reproduces FIG. 4.1 of 3GPP TS 36.300, and shows the overall architecture of the E-UTRAN system. The E-UTRAN system includes eNBs, providing the EUTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME (Mobility Management Entity) by means of a S1 MME interface and to a Serving Gateway (SGW) by means of a S1 interface. The S1 interface supports a many to many relationship between MMEs/Serving Gateways and eNBs.
The eNB hosts the following functions:
functions for Radio Resource Management: Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both uplink and downlink (scheduling);
IP header compression and encryption of the user data stream;
selection of a MME at UE attachment;
routing of User Plane data towards Serving Gateway;
scheduling and transmission of paging messages (originated from the MME);
scheduling and transmission of broadcast information (originated from the MME or O&M); and
measurement and measurement reporting configurations to provide mobility and scheduling.
Of particular interest herein are the further releases of 3GPP LTE targeted towards IMT-A systems, referred to herein for convenience simply as LTE-Advanced (LTE-A).
Reference can be made to 3GPP TR 36.814, V1.2.1 (2009-06), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Further Advancements for E-UTRA Physical Layer Aspects (Release 9). Reference can also be made to 3GPP TR 36.913, V8.0.1 (2009-03), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for Further Advancements for E-UTRA (LTE-Advanced) (Release 8). A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost.
As specified in 3GPP TR 36.913, LTE-A should operate in spectrum allocations of different sizes, including wider spectrum allocations than those of Rel-8 LTE, e.g., up to 100 MHz, to achieve the peak data rate of 100 Mbit/s for high mobility and 1 Gbit/s for low mobility. It has been agreed that carrier aggregation is considered for LTE-A in order to support bandwidths larger than 20 MHz. Carrier aggregation, where two or more component carriers (CC) are aggregated, is considered for LTE-A in order to support transmission bandwidths larger than 20 MHz. The carrier aggregation could be contiguous or non-contiguous.
A terminal may simultaneously receive one or multiple component carriers depending on its capabilities. An LTE-A terminal with reception capability beyond 20 MHz can simultaneously receive transmissions on multiple component carriers. An LTE Rel-8 terminal can receive transmissions on a single component carrier only, provided that the structure of the component carrier follows the Rel-8 specifications.
FIG. 1B shows an example of the carrier aggregation, where M Rel-8 component carriers are combined together to form MxRel-8 BW, e.g. 5×20 MHz=100 MHz given M=5. Rel-8 terminals receive/transmit on one component carrier, whereas LTE-A terminals may receive/transmit on multiple component carriers simultaneously to achieve higher bandwidths.
Moreover, it is required that LTE-A should be backwards compatible with Rel-8 LTE in the sense that a Rel-8 LTE terminal should be operable in the LTE-A system, and that a LTE-A terminal should be operable in a Rel-8 LTE system.
Of interest herein is E-UTRAN LTE-A idle mode mobility and load balancing. The carrier where a given UE is camping in the IDLE mode is unknown to the eNB. While the eNB has certain means to control the UEs as to which carrier they camp on, the control information is typically the same for all UEs and is not cell-specific. A particular UE changing from the IDLE state to the ACTIVE state consumes RACH resources in that cell. The UE becomes RRC-connected and, without being explicitly signaled, stays RRC-connected in that cell.
With further regard to carrier aggregation, what is implied is that one eNB can effectively contain more than one cell on more than one CC (component carrier), and the eNB can utilize one (as in E-UTRAN Rel-8) or more cells (in an aggregated manner) when assigning resources and scheduling the UE.
A Rel-8 UE will camp on a cell on a carrier frequency according to the absolute priority set for the frequencies. That is, the Rel-8 UE will attempt to camp on a cell of the highest priority frequency. Priorities used for the camping purpose are normally broadcast by the network, but the eNB can also signal dedicated priorities for the UE when the UE moves from the RRC_Connected to the RRC_Idle states, and these priorities remain in effect for some fixed duration (T320 timer, whose maximum length is 3 hours.) Using the broadcast technique for distributing frequency priority information implies that the UEs would all tend to camp on the same CC of the eNB. This can result in unbalanced UL load, for example, due to Random Access procedures.
Rel-8 assumes absolute priorities for frequency layers. With these, the UE attempts to stay on a highest priority layer as long as possible, while taking the radio conditions in the frequency layer into account. The UE uses certain thresholds (given by the network) into account (depending on radio conditions) when deciding whether to reselect to another carrier frequency. If the eNB signal level in the current frequency is worse than a given threshold, the UE is allowed to reselect to another frequency if an eNB signal level on that frequency is better than (another) given threshold.
The exact behavior and potential thresholds and parameters are described in more detail in 3GPP TS 36.304 V9.0.0 (2009-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode (Release 9), and in 3GPP TS 36.331 V9.0.0 (2009-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) Radio Resource Control (RRC); Protocol specification (Release 9).
Reference may also be made to R2-094545, 3GPP TSG-RAN-WG2 Meeting #66bis, Shenzhen, P. R. China, Aug. 24-28, 2009, "Carrier Aggregation-Paging Optimization", Motorola. In R2-094545 it is stated that in this option, both the UE and the network use a hashing function to determine an ordered list of preferred camping carriers, based on the UE-id (IMSI, for example). The UE always camps on the most preferred carrier, provided that the carrier is capable of camping and there is coverage of that carrier at the current location of the UE. Because the network also knows this hash function, it can determine the most likely carrier in which the UE is camping. An appropriate paging algorithm can then be designed to use this ordering to preferentially page the UE in one or more carriers of the UE as per the preferred list. The hashing function can be designed in a fashion that the UEs are distributed across the different component carriers to distribute the paging load evenly.


A vehicle length sensor for a vehicle such as a variable length truck, the sensor being provided with a mount for mounting the sensor on a vehicle and being arranged with a detection circuit arranged to measure, in use, a length of a vehicle to which the sensor is mounted. Typically, the detection circuit comprises a transmitter circuit, which is arranged to transmit radiation along the length of the vehicle, and a receiver circuit that is arranged to receive radiation that was transmitted by the transmitter circuit and reflected from the vehicle, and in which the detection circuit is arranged to determine from the reflected radiation the length of the vehicle. The sensor may also act as a lane change assistant, comparing the range of other vehicles to the length of the vehicle to which it is mounted.

This invention relates to vehicle length sensors, typically but not exclusively for vehicles such as may have variable length, and to a vehicle being provided with such a sensor.
The correct and quick determination by a driver of a vehicle of whether there is another vehicle alongside their vehicle is both essential for modern highway driving and is also potentially hazardous, particularly in situations where the driven vehicle has to change lanes, such as in an overtaking manoeuvre or when joining a highway. A vehicle may be in the blind spot—the area alongside the vehicle that cannot be viewed from the rear view mirrors of a vehicle. Even with a vehicle in the area visible in the rear view mirrors, a driver may be unable, be it through lack of skill, poor visibility or even through simply not having looked, to determine how close a vehicle is in an adjacent lane. This is particularly a problem with variable length vehicles, such as trucks, which can pull trailers of different lengths or numbers.
Blind spot detectors have been proposed which detect whether there is a vehicle immediately in the blind spot of the vehicle. However, they do not help a driver judge whether there is sufficient space to move into a given lane. Lane change assist detectors have also been proposed, which determine whether there is a fast-approaching vehicle in an adjacent lane; such detectors are more concerned with alerting a driver to a potential, rather than a present problem.


The invention is a method and apparatus for generating vortex rings in a fluid medium. The apparatus is immersed in a body of water, and an air pump feeds gas in the form of air directly into the base of the apparatus through a gas inlet or the gas is provided from a container with a finite quantity of gas. A nozzle extends from the gas inlet to a pocket located on an underside of a lever. As air is pumped into the pocket, the air forms a single bubble, and when the force of the air mass exceeds the weight of the lever, the lever rises and the air mass travels as a cohesive unit to an exit nozzle. When the lever reaches the maximum height displacement defined by a resilient upper stop, the air exits the lever through a nozzle and forms a vortex ring.

1. Technical Field
This invention relates to a method and apparatus for producing vortex rings of gas in a fluid medium. More specifically, the apparatus may operate automatically with a finite supply of a gas, or it may be connected to a supply of gas such that the vortex rings are generated automatically and continuously.
2. Description of the Prior Art
Vortex rings are aesthetically pleasing artifacts with behaviors and aspects that are very interesting to many people. A smoke ring, which is a form of a vortex ring made from a visible form of gas, can be made to traverse a small room, and even extinguish a candle flame several feet away from where the smoke ring was generated. However, vortex rings are not limited to smoke rings. A vortex ring of identical size to a smoke ring may be made of air instead of smoke. Such a ring comprises similar characteristics to a smoke ring, and can also travel invisibly across the same room and extinguish a candle flame. Vortex rings have been studied by students in the field of fluid dynamics, which is an important part of airplane design and other engineering disciplines.
Most people have only seen a vortex ring in the form of a smoke ring. However, there is another form of a vortex ring that can be studied and enjoyed without involving the many known severe dangers and drawbacks associated with the creation of smoke rings through the use of tobacco. This alternative form of a vortex ring is a ring made of a gas and travels vertically upward through a liquid medium. When created out of air within a medium of water, these vortex rings have also been known as bubble rings. They are enjoyable to play with and to study, although they have not been easy for the average person to generate.
Dolphins have also been known to generate bubble ring type vortex rings, possibly for the entertainment and enjoyment of the exercise. However, these vortex rings are not readily available for viewing by humans, of course, since dolphins live and swim in the depths of the Earth""s oceans, and have been captured on film creating bubble rings only a very few times. In addition, there is another place where vortex rings are thought to form which is of interest to people, and that is in the inside of some human""s hearts. If the studies are correct, the vortex rings are made of blood, and travel through the blood in the heart chamber, in patients with certain heart problems. Accordingly, there are several reasons why it is desirable to have a way to create vortex rings in a form that can be easily observed, studied, learned from and enjoyed.
There are several recent U.S. Patents which disclose different mechanical apparatus to aid in the production of vortex rings. In general, each of these patents relate to the generation of vortex rings in a fluid environment, such as water, with the use of air as the gas. For example, U.S. Pat. No. 5,947,784 to Cullen teaches an apparatus for use by a human being in a fluid immersed environment. The apparatus comprises an elbow shaped tool with an elongated horizontal portion, and an elbow leading to a short vertical portion. At the end of the vertical portion, the apparatus includes a valve assembly. The elongated portion of the apparatus allows air to exit the apparatus away from the user""s face and hands, so that the air and water near the short vertical portion is not exposed to any turbulence. The configuration of the valve body that closes when the user stops blowing air through the elongated portion causes the bubble of air that is released to be one large bubble of air, and helps produce the toroidal configuration of the vortex rings. In general, the valve assembly responds to short bursts of air through an elongated passageway to produce vortex rings. Alternatively, the elongated section of the apparatus may be connected to a source of gas under pressure. The introduction of a burst of gas under pressure causes the body of the valve to momentarily be unseated thereby allowing a burst of gas to escape and produce the toroidal shaped vortex ring. Accordingly, the Cullen patent requires a person to be immersed under water or for a gas under pressure to deliver short bursts of air to momentarily unseat the valve and to produce a vortex ring.
U.S. Pat. No. 4,534,914 to Takahashi et al. teaches an apparatus for producing vortex rings. The apparatus uses an accumulator in the form of a cylindrical cup, wherein gas enters the accumulator and exits through an outlet affixed with a nozzle. When the accumulator is in a non-operating position, the valve member is urged by a coil spring toward the gas outlet, causing a seal of the outlet. However, in order to produce the vortex rings, a gas under pressure is introduced to the accumulator thereby causing an increase in the pressure in the interior chamber of the accumulator. The pressure of the gas causes the diaphragm to be outwardly inflated against surrounding water pressure and the force of the spring, which altogether takes the valve member out of contact with the gas outlet and discharges a pocket of gas through an exit nozzle. The gas stored in the accumulator is discharged into the nozzle which is closed by water pressure so that the nozzle is instantaneously opened. Accordingly, the Takahashi et al. patent require gas under pressure to be supplied to a chamber, and based upon the pressure of the gas the valve is unseated resulting in the generation of a vortex ring.
Accordingly, what is desired is an apparatus for generating vortex rings which eliminates the need for supplying gas under pressure, and eliminates the necessity for manual operation. It is not desirable to have a human being supply short burst of air to a nozzle apparatus submerged in a fluid environment. The person submerged in the fluid will have to hold their breath and as such will not be able to provide short bursts of air to the apparatus for an extended period of time. In addition, the human error factor is significantly increased when a person is submerged under water without an independent supply of oxygen. Accordingly, it is desirable to provide a simple mechanical apparatus which can automatically generate vortex rings using a supply of pressurized or unpressurized gas.
It is therefore an object of the present invention to provide an apparatus for immersing in a fluid environment for generating vortex rings through the supply of a gas with or without pressure.
It is another object of the present invention to provide a method of generating a continuous supply of vortex rings through a supply of gas entering the apparatus.
It is an even further object of the invention to provide an apparatus that comprises a gas inlet that may be modified for accepting gas from a finite source or from an infinite source of air. The inlet directs the gas to a pocket on an underside of a lever. When the upward buoyancy of the gas in the pocket exceeds the downward weight of the lever, the lever moves upwards slightly, changing the tilt angle of the lever and allowing the gas within the pocket to exit the underside of the lever through a nozzle. Based upon the design of the nozzle and the state of the gas, a vortex ring is created.
It is a further object of the invention to provide an apparatus for immersion into a fluid environment and generating vortex rings from a finite supply of gas. The apparatus comprises a spring mechanism which remains closed in a rest position. A lever may be activated to supply a burst of air through an exit nozzle to produce a vortex ring.
These and other objects of the invention are produced through an apparatus and method for forming a vortex ring of gas in a fluid medium. The apparatus comprises a lever with a pocket formed within the underside of the lever at a proximal end, a hinge-type attachment at the proximal end of the lever which permits the lever to vertically pivot a limited distance, an inlet for introducing a gas to the underside of the lever, and a nozzle located at a distal end of the lever extending from an underside surface to a top surface. In addition, the apparatus comprises two adjustable stops, a lower stop for controlling downward displacement of the lever when it is in the lower position, and an upper stop for controlling upward displacement of the lever when the buoyancy of the gas lifts the lever. As gas is introduced to the underside of the lever by way of the inlet, the gas fills the pocket region on the underside of the lever. During the accumulation of the gas within the pocket, the buoyancy of the gas will become greater than the weight of the lever in the fluid. When the lift generated by the gas within the pocket region of the underside of the lever exceeds the downward pressure of the lever, the lever will rise tilting slightly upward and cause the gas to travel along an underside surface of the lever toward the nozzle. The shape and design of the underside of the lever, including a smooth gradual transition from the flat underside of the lever to the entrance of the nozzle, causes the gas to remain in a unitary bubble and allows the gas to exit the nozzle in a short burst generating a vortex ring. Accordingly, once the air under the lever has been released and the weight of the lever exceeds that of the gas within the pocket or there is no gas present in the pocket, the lever will return to the starting position adjacent to the lower stop once again prepared to begin the cycle of accepting air into the pocket region.

Apparatus for creating vortex rings in a fluid medium


Melt-processible, thermoplastic poly(tetrafluoroethylene) (PTFE) compositions are disclosed and methods for making and processing same. Additionally, products comprising these compositions are described.

This invention relates to melt-processible poly(tetrafluoroethylene) (PTFE), compositions thereof, articles formed therefrom, and methods for making the same. More particularly, the present inventions relates to a particular range of poly(tetrafluoroethylene) polymers which are readily melt-processible while maintaining good mechanical properties. Further, the present invention relates to products made of melt-processible, thermoplastic PTFE compositions.
Poly(tetrafluoroethylene) (PTFE) is well-known for, among other properties, its chemical resistance, high temperature stability, resistance against ultra-violet radiation, low friction coefficient and low dielectric constant. As a result, it has found numerous applications in harsh physico-chemical environments and other demanding conditions. Equally well-known is the intractability of this important polymer. Numerous textbooks, research articles, product brochures and patents state that PTFE is intractable because, above its crystalline melting temperature, it does not form a fluid phase that is of a viscosity that permits standard melt-processing techniques commonly used for most thermoplastic polymers (Modern Fluoropolymers, J. Scheirs, Ed. Wiley (New York), 1997; The Encyclopaedia of Advanced Materials, Vol. 2, D. Bloor et al. Eds., Pergamon (Oxford) 1994; WO 94/02547; WO 97/43102). Suitability of a polymer for standard melt-processing techniques may be evaluated, for example, through measurement of the melt-flow index (MFI) of the material (cf. ASTM D1238-88). Melt-processible polymers should, according to this widely employed method, exhibit at least a non-zero value of the melt-flow index, which is not the case for common PTFE under testing conditions that are representative of, and comparable to those encountered in standard polymer melt-processing. The extremely high viscosity of PTFE, reported to be in the range of 101014 1013 Pa.s at 380xc2x0 C., is believed to be associated, among other things, with an ultra-high molecular weight of the polymer, which has been estimated to be in the regime well above 1,000,000 g/mol and often is quoted to be of the order of 10,000,000 g/mol. In fact, it is claimed (Modem Fluoropolymers, J. Scheirs, Ed. Wiley (New York), 1997, p. 240) that xe2x80x9cto achieve mechanical strength and toughness, the molecular weight of PTFE is required to be in the range 107-108 g/mol . . . xe2x80x9d. Due to this high viscosity, common PTFE is processed into useful shapes and objects with techniques that are dissimilar to standard melt-processing methods. Rods, sheets, membranes, fibers and coatings of PTFE are produced by, for example, ram-extrusion, pre-forming and sintering of compressed powder, optionally followed by machining or skiving, paste-extrusion, high isostatic pressure processing, suspension spinning, and the like, and direct plasma polymerization.
Illustrative for the difficulties encountered in processing common PTFE are the complex and indirect methods by which fibers are produced from this polymer. Polytetrafluoroethylene fibers have been produced, as described in U.S. Pat. No. 3,655,853, by forming a mixture of viscose and PTFE particles in a dispersion, extruding the mixture through a spinneret into an acidic bath to form fibers consisting of a cellulosic matrix containing the PTFE particles. After washing and rinsing, the fibers are heated to a temperature of about 370xc2x0 C. to 390xc2x0 C. to decompose the cellulosic material and to melt and coalesce the polymer particles. The fibers are then drawn at a ratio of about 4:1 to 35:1 typically at a temperature between 370xc2x0 C. and 390xc2x0 C. The fibers produced by this relatively complex and expensive process may require further processing steps, such as bleaching to remove residual contaminants, which commonly lowers the tensile strength. Another method to produce fibers of PTFE is described in U.S. Pat. Nos. 3,953,566, 3,962,153, and 4,064,214. In this method a paste formed by mixing a lubricant, such as a mineral spirit, with a fine powder of PTFE produced by coagulation of an aqueous dispersion of PTFE particles, is extruded and formed to produce a tape, film or bead. The product thus formed, is slit to form fibers, is dried to remove the lubricant and subsequently stretched at a high rate, and at a temperature lower than the crystalline melt point of PTFE, to produce a porous article. The porous article is then heated while maintained in the stretched condition to a temperature above the melt point of crystalline PTFE, generally considered to be in the range 327xc2x0 C. to 345xc2x0 C., to increase strength. Alternatively, PTFE fibers are produced by first forming a solid preform by sintering the polymer for prolongued periods of time above the melting temperature of the polymer and cooling the mass down to room temperature, which is a process that may take as much as 48 hrs. Subsequently, PTFE fibers are cut from the preform by the well-know skiving method, typically yielding fibers of high denier ( greater than  greater than 100).
Unfortunately, the above methods generally are less economical than common melt-processing, and, in addition, severely limit the types and characteristics of objects and products that can be manufactured with this unique polymer. For example, common thermoplastic polymers, such as polyethylene, isotactic polypropylene, nylons, poly(methylmethacrylate) polyesters, and the like, can readily be melt-processed into a variety forms and products that are of complex shapes, and/or exhibit, for example, some of the following characteristics: dense, void-free, thin, clear or translucent; i.e. properties that are not readily, if at all, associated with products fabricated from PTFE.
The above drawback of PTFE has been recognised virtually since its invention, and ever since, methods have been developed to circumvent the intractability of the polymer. For example, a variety of co-monomers have been introduced in the PTFE macromolecular chains that lead to co-polymers of reduced viscosity and melting temperature. Co-polymers are those that are polymerized with, for example, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), or perfluoro-(2,2-dimethyl-1,3-dioxole), partially-fluorinated monomers and combinations thereof, in addition to the tetrafluoroethylene monomer. Several of the resulting co-polymers (for example, those referred to as FEP, MFA, PFA and Teflon(copyright) AF) provide improved processibility, and can be processed with techniques for common thermoplastic polymers (WO 98/58105). However, a penalty is paid in terms of some or all of the outstanding properties of the homopolymer PTFE, such as reduced melting temperature and thermal and chemical stability.
Additional methods to process the PTFE homopolymer include, for example, the addition of lubricants, plasticizers, and processing aids, as well as oligomeric polyfluorinated substances and hydrocarbyl terminated TFE-oligomers (for example, Vydax(copyright) 1000) (U.S. Pat. Nos. 4,360,488; 4,385,026 and WO 94/02547). The latter method, however, is directed to the improvement of the creep resistance of common PTFE which results in a bimodal morphology with two distinct melting temperatures, and generally does not lead to homogeneous PTFE compositions that can be melt-processed according to standard methods. For example, only a hot-compression molding method is heretofore known for mixtures of standard PTFE and Vydax(copyright) 1000, that preferably is carried out in the narrow temperature range between about 330xc2x0 C. to 338xc2x0 C. The other aforementioned additions of lubricants, plasticizers, and processing aids also do not yield truly melt-processible PTFE compositions. Solution processing, at superautogeneous pressure, of PTFE from perfluoroalkanes containing 2-20 carbon atoms has been disclosed in WO 94/15998. The latter process is distinctly different from melt-processing methods. Also disclosed is dispersion, and subsequent melt-processing of standard PTFE into thermoplastic (host-) polymers such as polyetheretherketone and polyphenylene sulfide (WO 97/43102) and polyacetal (DE 41 12 248 A1). The latter method compromises important physico-chemical properties of the resulting composition, when compared to neat PTFE, or requires uneconomical and cumbersome removal of the host material.
There exist PTFE grades of low molecular weight and of low viscosity. These grades, which are often are referred to as micropowders, commonly are used as additives in inks, coatings and in thermoplastic and other polymers to impair, for example, nucleation, internal lubrication or other desirable properties that, in part, stem from the unique physico-chemical properties of the neat PTFE. Low molecular weight PTFE grades, in their solid form, unfortunately, exhibit extreme brittleness and, according to at least one of the suppliers, these PTFE grades . . . xe2x80x9care not to be used as molding or extrusion powdersxe2x80x9d (Du Pont, Zonyl(copyright) data sheets and url:http://www.dupont.com/teflon/fluoroadditives/about.htmlxe2x80x94Jul. 7, 1998).
Thus, a need continues to exist to develop melt-processible, thermoplastic poly(tetrafluoroethylene)s to exploit the outstanding properties of this polymer in a wider spectrum of product forms, as well as to enable more economical processing of this unique material.
Surprisingly, it has been found that poly(tetrafluoroethylene)s of a particular set of physical characteristics provide a solution to the above, unsatisfactory situation.
Accordingly, it is one objective of the present invention to provide melt-processible, thermoplastic PTFE compositions of good mechanical properties comprising PTFE grades that are characterized as having a non-zero melt-flow index in a particular range. As used herein, the indication xe2x80x9cgood mechanical propertiesxe2x80x9d means the polymer has properties suitable for use in thermoplastic applications, and exhibits an strain at break of at least 10% or a stress at break of greater than 15 MPa, determined under standard ambient conditions at a strain rate of 100% per min.
Yet another object of the present invention is to provide melt-processible PTFE of good mechanical properties that exhibit a plateau value of the complex viscosity measured at frequencies below about 0.01 rad/s and at a temperature of 380xc2x0 C. and strong shear thinning that is in a range beneficial for processing.
Still another object of the present invention is to provide melt-processible PTFE of good melt stretchability.
Another object of the present invention is to provide melt-processible PTFE that in its unoriented solid form has a crystallinity of between about 1% and about 60% and good mechanical properties.
Still another object of the present invention is to provide a melt-blending method that yields melt-processible, thermoplastic PTFE compositions of good mechanical properties comprising PTFE grades that are characterized in having a non-zero melt-flow index in a particular range.
Additionally, it is an object of the present invention to provide a method to melt-process PTFE compositions that comprise PTFE grades that are characterized in having a non-zero melt-flow index in a particular range, into useful shapes and articles of good mechanical properties.
Still another object of the present invention is to provide useful shapes and articles of good mechanical properties that are manufactured by melt-processing of PTFE compositions that comprise PTFE grades that are characterized in having a non-zero melt-flow index in a particular range.
Yet another object of this invention is to provide novel useful shapes and articles that comprise PTFE.
Yet a further object of this invention is to provide a composition comprising tetrafluoroethylene polymer, or blend of two or more tetrafluoroethylene polymers wherein said polymer or said blend of two or more polymers has a melt-flow index of between 0.2-200 g/10 min and is extensional or shear flow processible.
The present invention provides a melt-processible fluoropolymer having a peak melting temperature of at least 320xc2x0 C. and good mechanical properties. And compositions and articles comprising at least in part a continuous polymeric phase comprising a melt-processible fluoropolymer having a peak melting temperature of at least 320xc2x0 C. and good mechanical properties.
The present invention also provides a composition comprising a melt-processible tetrafluoroethylene polymer, or a melt-processible blend of two or more tetrafluoroethylene polymers wherein said polymer or said blend of two or more polymers has good mechanical properties. And a process for producing a melt-processible composition comprising a melt-processible tetrafluoroethylene polymer, or a melt-processible blend of two or more tetrafluoroethylene polymers wherein said polymer or said blend of two or more polymers has good mechanical properties. Also a method for producing an article comprising melt-processing a composition comprising a melt-processible tetrafluoroethylene polymer, or a melt-processible blend of two or more tetrafluoroethylene polymers wherein said polymer or said blend of two or more polymers has good mechanical properties.
Another aspect of the present inventions includes using the melt-processible polymer or polymer composition as an adhesive. The present invention provides a process for connecting parts comprising adhering a part to at least one further part with the polymer or composition of the present invention.
Additional objects, advantages and novel features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art on examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.


A fluid controller includes a valve housing having an inlet port, a return port, first and second control ports and a load sense port. The fluid controller further includes a fluid meter in selective fluid communication with the valve housing and a valve assembly adapted to provide selective fluid communication between the valve housing and the fluid meter. The valve housing includes a main flow path and a load sense flow path. The main flow path is adapted to provide selective fluid communication between the inlet port and the first control port. Fluid in the main flow path passes through the fluid meter. The load sense path is adapted to provide selective fluid communication between the load sense port and the main flow path. The load sense flow path includes a variable load sense orifice that substantially closes prior to a maximum rotational displacement of the valve assembly.

Fluid controllers are used in many applications to control the flow of fluid from a source of pressurized fluid, such as a vehicle pump, to a fluid pressure operated device, such as a vehicle steering cylinder. Many applications use fluid controllers that have load sense circuits and flow amplification. In fluid controllers with flow amplification and manual steering capability, the flow amplification peaks at roughly 50 to 60 rpm and then begins to decline as the steering speed increases. However, in some applications, this is not desirable since the operator expects more responsive steering at faster steering speeds.

Fluid controller with load sense and flow amplification


Methods, systems, and apparatus, including computer program products, are provided for refining quilts of patches representing three dimensional structures. A method is provided that includes generating a first quilt representation of a three-dimensional structure, adding information to the first quilt representation, and generating a second quilt representation based on the first quilt representation. The first quilt representation is based on a model and associated with a first display level of detail. The second quilt representation is associated with a second display level of detail higher than the first display level of detail.

Various three-dimensional (3D) modeling systems use geometric models of structures with varying degrees of precision. Some systems use both a precise model (for instance, a Boundary Representation model) and an approximate mesh representation (for instance, a mesh of triangles) that is based on the precise model. The system generates the mesh representation by faceting (in other words, tessellating) the precise model. The system uses the mesh representation, rather than the precise model, for display in some situations to save memory or processing time or both. In some 3D modeling systems, display hardware is optimized to display mesh representations.
When a 3D modeling system displays a structure using a mesh representation, the display of the structure can be good in certain views and bad in other views. For example, the system can load a mesh representation of a structure with sufficient detail (that is, a sufficient display level of detail) so that it accurately represents a precise model of the structure when the user is viewing it at a 50% zoom level. But when the user zooms in to a 100% zoom level, the mesh representation can appear to be different from the precise model. A 3D modeling system may not generate a new mesh representation when the user zooms in to save memory or processing time or for other reasons.
FIG. 1A shows a mesh representation 100 of a model of a structure displayed at a first zoom level. The mesh representation 100 is associated with a display level of detail appropriate for the first zoom level. At this first zoom level, the circular holes 102 appear to be perfect circles. FIG. 1B shows the same mesh representation 100 displayed at a second zoom level. At this second zoom level, the circular holes 102 appear to have jagged edges.
A mesh representation that appears differently than expected can be alarming to a user. In particular, a user of Computer Aided Design (CAD) software may be designing precise mechanical structures that need to fit other structures or have certain structural properties. If a structure does not appear as specified in a precise model, the user can become distrustful of the entire system.
One technique for improving the appearance of meshes of triangles involves replacing flat triangles with cubic Bezier patches, a curved shape that can be divided (by faceting) into a number of smaller flat subtriangles. Each original triangle includes, for each of its vertices, a surface normal vector. The surface normal vectors are typically included with a mesh of triangles to permit advanced shading or for other purposes. However, the surface normals can be used to determine Bezier control points associated with the triangles. The triangles, including their surface normal vectors and Bezier control points, are known as "curved point-normal triangles," "PN triangles," or "N-patches" (hereafter "N-patches"). TRUFORM technology by ATI Technologies, currently owned by Advanced Micro Devices (AMD) of Sunnyvale, Calif., uses N-patch techniques.

Refining quilts of patches representing three dimensional structures


A production well arrangement that includes a vertical main well extending into a gas producing strata and an access hole having a vertical portion coupled to a curved portion, which is coupled to a lateral portion. The vertical portion has an upper end defined on the ground surface and is laterally offset from the vertical main well. The lateral portion has a lateral end intersecting the vertical main well at an intersection point positioned between an upper end and lower end of the vertical main well, wherein the lateral end of the lateral portion does not extend beyond the vertical main well. One or more laterally extending holes extends from an intercepted zone defined on the access hole, which is upstream of the intersection point, wherein the one or more laterally extending holes do not intersect the vertically extending well.

1. Field of the Invention
The present invention relates generally to systems and methods for the recovery of subterranean deposits and, more particularly, to an arrangement and method for removal of fluid and the production of gas from a desired subterranean formation.
2. Description of Related Art
Subterranean formations often contain desirable fluids and gases that can be used for many applications. Subterranean formations can include but not limited to coal beds (also referred to as coal seams), carbonaceous shales, silicious shales, sandstone, chalk or any target formation containing hydrocarbons.
Coal is a large energy source. It has been mined from the earth for many years. Deposits of coal beneath the ground surface are positioned in generally horizontal coal seams and include substantial quantities of methane gas entrained in the coal deposits. In underground coal mining, methane gas poses a significant safety risk to the miners. In the past, the methane gas entrained in the coal deposits was simply liberated from the coal, mixed with air in the mine which diluted it to a safe concentration, and the mixture was ventilated to the outside environment. The methane was simply dissipated into the environment and provided no meaningful resource. However, in recent years, there has been a thrust to use the entrained methane gas as an efficient energy source and sell it commercially. Typically, the methane gas can be used as a driving source for energy-producing equipment, such as generators or the like, or can be added to natural gas pipelines.
Utilizing the gas as an energy source requires that the gas be extracted in a concentrated state and captured. Extracting methane from the coal seams in a concentrated state has been achieved by drilling boreholes, generally horizontally, into the coal seam that can extend several thousands of feet.
During and after the methane drilling process, dewatering must occur. Since coal seams may have a significant amount of subterranean water associated with them, water must be drained from the coal seam in order to produce the methane. Further, during the drilling process, water may be used at the drilling tip, creating a slurry of drill cuttings, which also must be removed from the borehole. Water and drill cuttings can block the migration of gas through the coal seam to the borehole and therefore must be removed to permit degasification. Additionally, some of the water used in the drilling process can be forced under pressure into the coal seam, further saturating the gas reservoir, which impedes the migration of gas to the borehole. Therefore, dewatering must occur both during the drilling process and after drilling has been completed.
Long, generally horizontal boreholes that remain in the coal seam are the most effective manner to extract and capture the gas entrained in the coal seam. A horizontal well, or horizontal portion of a main well bore may extend over a significant length of the coal seam and intersect multiple natural fractures within the coal seam which provide a passageway for fluid to migrate to the well bore. By "fluid" means all liquids and gases including but not limited to water, brine, chemically entrained liquids, foam, air, nitrogen or hydrocarbons injected into and/or removed from a well.
When drilling horizontal and/or vertical wells targeting low pressure reservoirs containing hydrocarbons, it is desirable to use under-balanced drilling. Under-balanced drilling is a method of drilling a desired subterranean formation, whereby the hydrostatic pressure exerted by a column of drilling fluid in the well bore and/or exiting the drill string tip is less than a natural formation pressure inherent in the targeted subterranean formation. Under-balanced techniques are utilized to prevent damage to the desired subterranean formation and, in particular, low pressure formations. The introduction of air, nitrogen or other gases to the drilling fluids reduces the density of the co-mingled fluids and effectively decreases hydrostatic pressure. Other low-density fluids such as chemical foams and air mists (compressed air and water) may be used as a drilling fluid to achieve an under-balanced condition. The under-balanced environment prevents damage to the formation and facilitates the removal of cuttings and drilling fluids through the curve and vertical sections of the main well bore to the surface, during drilling operations.
One prior art method used to remove desirable fluids is described in U.S. Pat. No. 6,280,000, issued to Zupanick. This method uses both a horizontal well and a vertical well that intersect each other. However, this method utilizes drilling of a large cavity in the vertical well. The enlarged cavity is more costly and requires a longer period of time to construct. The large diameter cavity can induce unstable conditions at the intersections of the horizontal and vertical well bore that causes the exposed coal and/or rocks to fall and accumulate within the cavity or well bore. This accumulation may impair removal of fluids from the cavity or well bore.
Another prior art method used to remove fluids is described in U.S. Patent Publication No. 2005/0051326 to Toothman, Jr. et al. This method also uses both a horizontal well and a vertical well that intersect each other, wherein compressed air typically injected into the vertical well creates an under-balanced condition during the drilling process. However, the compressed air can also flow into the horizontal laterals in the coal seam of the main well bore and into any other additional laterals that extend from the main horizontal lateral, thus further saturating the gas reservoir which may impede the migration of gas from the formation to the borehole.
The present invention overcomes the above deficiencies by only having one direction that the compressed air can flow, with minimal, if any, air flow into the horizontal laterals extending into the subterranean formation while maintaining an under-balanced condition.

Under-balanced directional drilling system


An apparatus for generating an FSK-modulated optical signal has an optical two-filter FSK super-heterodyne receiver. The optical signal has two different polarization conditions that are orthogonal to one another. Due to the two-filter receiver and orthogonal conditions, polarization-independent reception is possible. Conversion of the polarized, optical signal into the optical signal having the orthogonal polarization conditions is accomplished by a switching device. Each condition has a corresponding bit status of a data signal. The data signal effectively controls the polarizatiion of the optical signal. Hence, the frequency boost can be freely selected while maintaining excellent bandwidth characteristics and optimum sensitivity.

1. Field of the Invention
The invention relates to an apparatus for generating an FSK-modulated optical signal for an optical transmission system having an optical FSK super-heterodyne receiver.
2. Description of the Prior Art
In standard optical receivers having super-heterodyne reception, such as optical heterodyne receivers, fluctuation of the amplitude of the intermediate frequency signal is dependent upon the relative position of the polarization conditions of the optical data signal and of the optical signal of a local oscillator. For optimum transmission quality, these fluctuations must be kept as low as possible. Common solutions to this problem are polarization follow-up with a control loop, as disclosed in Electron. Lett. 22 (1986), pp 1341-1343; polarization quadrature reception, Electron. Lett. 22 (1987), pp 168-169; and polarization scrambling, Electron. Lett. 23 (1987), pp 513-514.
The receivers having polarization follow-up theoretically achieve high sensitivity. However, the outlay for the control circuitry in such receivers is considerably large.
Polarization quadrature receivers represent a reliable alternative, but require a division of the optical signals into two sub-signals that are polarized so that they are orthogonal to one another. Each of the sub-signals requires its own receiver.
Both the polarization follow-up and polarization quadrature methods demand an increased outlay in the receiver. This drawback is problematical in many receiver applications.
In polarization scrambling, as opposed to polarization receivers, the increased outlay can be shifted onto the transmitter side. In this method, the polarization condition of the data signal is repeatedly switched between orthogonal polarization stakes in a statistical manner during the bit duration. This allows for the mean value of different polarization conditions to be represented by the intermediate frequency signal. Theoretically, the sensitivity loss in this method compared to the ideal polarization follow-up amounts to at least 3dB. For higher data rates, extremely fast polarization switches are required and the required receiver band width is significantly increased.
It is well-known to have different polarization conditions of an FSK-modulated optical signal that are orthogonal to one another. As in light waveguide links, orthogonal polarization conditions or states remain largely preserved over relatively long optical transmission paths. As a result, polarization-insensitive reception is possible. Such an apparatus is disclosed in Electron. Lett. 24 (1988), pp. 358-360.
The known method for generating the FSK-modulated optical signal, which exhibits the two polarization conditions that are different from one another, is sending the FSK-modulated, polarized optical transmission signal through a highly birefringent medium. After passing therethrough, the two optical frequencies of the FSK-modulated optical transmission signal, the first corresponding to a bit status of 0 and the second corresponding to a bit status of 1, are orthogonal to one another. This condition will only be met for a certain value of the difference between these two frequencies. For this reason, the frequency shift .DELTA.f must be selected large in comparison to the data rate so that any deviation from the orthogonality will be negligible within the signal bandwidth. In the known method, a frequency shift of .DELTA.f-1 GHz is selected for a data rate of only 50Mbit/s. This prior art apparatus is limited because it is only suitable for an optical transmission system having an optical two-filter FSK super-heterodyne receiver.

Apparatus for generating an FSK-modulated optical signal having two different polarization conditions for an optical transmission system having an optical two-filter FSK super-heterodyne receiver


A technique for classifying a message is disclosed. The technique includes determining the domain from which the message is purported to be sent, determining an IP address from which the message was relayed at some point in its transmission, associating the domain with the IP address, and classifying the message based on the associated domain and IP address.

Electronic messages have become an indispensable part of modern communication. Electronic messages such as email or instant messages are popular because they are fast, easy, and have essentially no incremental cost. Unfortunately, these advantages of electronic messages are also exploited by marketers who regularly send out unsolicited junk messages. The junk messages are referred to as "spam", and spam senders are referred to as "spammers". Spam messages are a nuisance to users. They clog email inboxes, waste system resources, often promote distasteful subjects, and sometimes sponsor outright scams.
There are a number of commonly used techniques for classifying messages and identifying spam, such as black listing the sender addresses of known spammers. However, these techniques sometimes misclassify spam messages. For example, a system that performs black listing may be configured to identify any messages with certain sender addresses, such as "firstname.lastname@example.com" as spam. However, spammers can insert a false sender address into a spam message, enabling the spam message to pass through the black listing filter. Another problem is that spammers may spoof a genuine sender address or domain that has been whitelisted by a user. It would be useful to have a technique that more accurately classifies messages. Such a technique would not be effective if spammers could easily alter parts of the spam messages they send so that the messages are identified as non-spam. Thus, it would also be desirable if non-spam messages identified by such a technique are not easily spoofed or if such spoofing could be detected.

Message classification using domain name and IP address extraction


A computer system for simultaneously sampling multiple light channels is configured to emit a first pulse-oximetry light signal from a first light source and to emit a second pulse-oximetry light signal from a second light source. The computer system then captures a combined pulse-oximetry signal from both the first pulse-oximetry light signal and the second pulse-oximetry light signal simultaneously at a photoreceptor sensor. The computer system identifies information within the combined pulse-oximetry signal, wherein the first light source and the second light source capture different attributes of the information.

The convergence of technology and medicine has led to stunning improvements in health and medical management. For example, MRIs, CAT scans, sonograms, and other related imaging technologies have provided medical researchers with previously unobtainable insight into the processes of the human body. Using these devices, doctors are able to diagnosis and treat a wide variety of diseases and conditions that previously were not treatable.
In addition to providing tools for medical practitioners, medical devices have increasingly become available to the public for personal use. For example, many wearable devices now include technology for tracking an individual's heart rate. One such technology that makes this possible is pulse oximetry. Pulse oximetry measures blood oxygen saturation (SpO2) by exposing the body to two or more wavelengths of light (e.g., red and infra-red). A computer processor then compares the difference in pulsatile amplitude at the two wavelengths.
Many conventional pulse oximetry devices utilize light sources, such as LEDs, and a photodiode to detect the light emitted by the light sources. When the optical paths from the photodiode to the two light sources is equivalent, and when ambient light doesn't change during sampling, this provides enough information to discern SpO2 with reasonable accuracy.
There is, however, a need in the field to increase the accuracy and efficiency of pulse-oximetry systems. In particular, pulse-oximetry systems that are used in mobile and/or power constrained configurations must deal with several unique challenges that do not arise in conventional hospital-based systems that typically have a non-limited power supply and a controlled operating environment.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.

Simultaneous multi-LED pulse-oximetry sampling


To carry out measurements in the vacuum, for example for quality control in the production of semiconductors, conventional stand alone measuring machines are installed. They are very cost, space and time intensive. To enable a process oriented measurement under optimal conditions, a device with a two part case is proposed that can be moved in a vacuum chamber, whereby one part of the case projects into the vacuum chamber and the other part of the case is located outside the vacuum chamber. The case can receive a measurement system. In addition, an adjusting device, engaging with the case, and a counterpull device, engaging with the second part of the case, are provided.

The invention relates to a device to carry out measurements in a vacuum chamber, in particular to measure thin layers, with a case, exhibiting at least one measurement window, to receive a measurement system.
Furthermore, the invention relates to a vacuum adapter for mechanisms to carry out optical measurements in a vacuum chamber.
Measurements in the vacuum, in particular for quality control, are quite important, for example, in the production of semiconductors. The most frequent variables to be measured are, for example, the thickness of the thin functional layers ranging from a few nanometers to some micrometers and the size and distribution of the particles. With the transition to smaller structures and larger wafer diameters, the demand for process-accompanying quality control increases. The goal is the early detection of errors and the correction of process parameters to increase the yield and the productivity of the production process. The higher the requirements of the quality control are, the more often the wafers have to leave the production process in order to be subjected to a random measurement.
The state of the art includes the so-called stand alone measuring machines, which are installed at central points of the plant. Due to the high cost of these systems and the relatively high space requirement, only a few of these systems can be installed. One drawback is also the additional paths, the additional loading and unloading steps of the wafers from the transport boxes and back again. Moreover, much time is lost between the detection of a defect and the reaction, a state that can result in enormous losses as the process speed increases and the value of the individual wafers increases dramatically.
To improve the yield and to reduce the production cycles precisely in thin film production, the layer properties of the thin films should be measured as process oriented as possible. One preferred method for measuring the refractive index and the thickness of thin layers is ellipsometry. It exploits the change in the polarization state of the light after its reflection on the sample surface. In addition, the collimated and fully polarized light is focused on the sample at a specific angle of incidence. In addition to the reflection, the polarization state of the radiation changes as a function of the properties of the sample.
In the case of ellipsometric measurements for determining the coating parameters in production processes not only stand alone machines have been used, but there has also been an attempt to measure the coating parameters in situ. The EP 0 527 150 B1 proposes an arrangement for ellipsometric in situ measurements in an industrial coating system. The ellipsometer, according to the EP 0 527 150 B1, exhibits a so-called paddle, on which not only the wafers to be measured are disposed but also the analyzing and the polarizing unit as well as the beam deflecting units are disposed in the form of prisms. Both for the incident beam and for the reflected beam a tube is provided as the beam tube. In a preferred embodiment these two tubes are also fastened to the paddle.
This ellipsometer arrangement has grave drawbacks. To carry out the measurement with an adequately good angle of incidence (usually between 65 and 75 degrees), it is a drawback with respect to production engineering that the coating furnace, which was optimized for a high throughput, cannot be fully filled, because minimum spacing must be maintained between the wafer to be measured and its neighboring wafer. Since the coating furnace is filled differently than what would correspond to the optimized state, the flow conditions in the furnace change and thus the quality of the coating.
From the view point of measurement technology it is quite disadvantageous that the pumps, which are typical in a vacuum chamber, excite the tube and the paddle to self sustained oscillation, the results of which are falsified measurements. The high temperatures and gases, generated during production, have a negative impact on the measurement results, since prism wall deposits and thermally induced stresses can be expected.
The object of the invention is to provide a device to carry out the measurements in the vacuum. Said device ought not to exhibit either the drawbacks of the stand alone devices or the in situ measuring devices, but rather permit a process oriented measurement under optimal measurement conditions.
This problem is solved by a device, according to claim 1. In addition, the problem is solved by a vacuum adapter, according to claim 14.
The case of the inventive device is divided into two parts, of which the first part projects into the vacuum chamber or defines with at least one surface the vacuum of the vacuum chamber; and the second part of the case is located outside the vacuum chamber.
The vacuum chambers are not the process vacuum chambers, but, for example, transfer or lock chambers of the production system. Special measurement chambers, to which the inventive device can also be attached, can also be integrated into the production system. The samples to be measured are brought to the device for measurement purposes by means of the transport means, such as robots, which are present in the production system in any event. Then said samples are positioned in the immediate vicinity of the first part of the case.
The inventive device exhibits at least one adjusting device, which engages with the case and whose purpose is to change the position relative to the vacuum chamber or relative to the sample to be measured. Thus, it is guaranteed that the device can be adjusted prior to each measurement, a condition that can be necessary for many a measuring method. It is necessary especially when the demands on the measuring accuracy are high or when the positioning of the sample by the transport means in the process system is too inaccurate.
It is possible to adjust the device prior to every measurement without interrupting the production process by means of the means to dispose sealingly and moveably the case in the wall of the vacuum chamber. In addition, with these means the device can be uncoupled mechanically from the vacuum chamber. Furthermore, the device can be assembled and tested independently of the vacuum chamber.
The inventive device exhibits a counterpull device, which engages with the second part of the case and permits a force to act that acts against the force, acting on the device owing to the negative pressure of the vacuum of the vacuum chamber. Thus, the goal of a force-free and tension-free state of the device is achieved, a state that leads to a better operating mode of the individual components and a higher reliability and measuring accuracy. In particular, it makes it easier to adjust the device. Even the mechanical uncoupling of the device from the vacuum chamber is thus increased. A special advantage lies in the fact that the arrangement eliminates the need to use especially heavy duty motors for the adjusting device. Consequently small motors and correspondingly weak spindle drives, which have to be designed only to compensate for any reset forces of the means to dispose the case in a sealed and moveable manner in the wall of the vacuum chamber, are sufficient.
It has proved advantageous to install, among other things, bellows as the means for the sealing and moveable arrangement of the case in the wall of the vacuum chamber. Since the bellows do not exhibit any rigid expansion, they permit the position of the device to be adjusted in relation to the vacuum chamber or to the sample to be measured without having to accept any losses in the sealing effect. In addition, said bellows damp possible oscillations of the vacuum chamber relative to the device. In the event of lower vacuum and minimum adjustment paths, elastic seals are also conceivable.
To apply the counterforce, a spring suspension or a magnetic suspension is, for example, also conceivable. Preferred is a negative pressure chamber that is formed on the side of the device opposite the vacuum chamber and which is evacuated either separately or is connected to the large vacuum chamber of the production system by way of a vacuum connection so that the pressure is automatically compensated. In this second case the negative pressure chamber has a variable volume. Advantageously the measurement system is housed in the second part of the case.
In the measurement system there is an input signal, which is converted into a measurement signal through interaction with the sample. The input signal can be arbitrary electromagnetic waves. The input signal can be generated either directly in the measurement system or fed from outside the measurement system into the measurement system and can be, for example, monochromated or modulated there or modified differently to match the measurement conditions.
In addition, the measurement system includes at least one detector, which serves to detect the measurement signal. The evaluation of the measurement signal can take place in the measurement system. However, for the purpose of evaluation, the detection signal can also be sampled from the measurement system or stored inside or outside the measurement system.
The first part of the case serves to form the boundary between the vacuum in the production system and the atmosphere, i.e. usually air, in the measurement system in the second part of the case. The interface can be designed, for example, as a window, which is appropriate for a vacuum or a high vacuum and which is transparent for the input signal and the measurement signal.
Preferably the measurement system of the device, according to the invention, is designed in such a manner that it exhibits not only the at least one detector but also at least one light source or light feed, such as a fiber optic cable. Thus, optical measurements in the vacuum can be carried out with the device, according to the invention. The embodiment of the inventive device is appropriate especially for measurements on the surface of a sample, such as ellipsometric measurements to determine the thickness and the refractive index of coatings or also to determine the existing particles by measuring the scattered light or measuring the loss of the direct reflection on the sample or in a volume. These applications are appropriate especiallyxe2x80x94but not onlyxe2x80x94for the quality control in production processes in the semiconductor industry.
To carry out optical measurements in the vacuum, the first part of the case is designed as a vacuum adapter and exhibits a beam tube, through which the incoming beam is guided as the input signal, which was generated by the light source in the measurement system, and through which the emerging beam of the measurement signal is guided. The incoming beam does not have to be automatically generated by a light source inside the measurement system, but rather can also be generated outside the measurement system and be fed to the measurement system, for example, by way of light guide cables and emerge there as a light beam. The beam tube of the vacuum adapter is fastened with one end to that part of the case that contains the measurement system. By means of the vacuum adapter, it is possible to couple in, for example, an ellipsometer, a reflectometer and/or an FTIR [=Fourier transform infrared] spectrometer.
To ensure the desired measurement configuration or measurement geometry at the measurement site, the vacuum adapter exhibits advantageously a prism and/or a lens system on the end of the beam tube that faces the vacuum chamber. Beam properties, like divergence, dispersion and angle in relation to the sample, can be adapted to the specific features directly before the measurement and directly after the measurement. In lower vacuum it is possible to seal the prism or the lens system so as to be vacuum tight with the beam tube so that these optical elements act as interfaces between the atmosphere in the beam tube or the measurement system and the vacuum outside the device.
If the goal is supposed to be a very high measurement accuracy, the preferred solution is that such optical elements as the prisms or the lenses be located completely in the vacuum, since otherwise stress could be generated inside this optical system. The end of the beam tube that faces the measurement system exhibits advantageously a window, which is appropriate for a vacuum and is transparent to light of any wavelength. This vacuum window separates the atmosphere in the measurement system from the vacuum of the beam tube or the vacuum chamber. A vacuum prevails inside the beam tube.
Especially for ellipsometric applications of the device, it is advantageous to dispose the polarizer not necessarily in the measurement system, but rather to attach the polarizer on the beam tube interior or beam tube exterior of the prism system of the vacuum adapter. If a very high degree of polarization is relevant, the polarizer is attached preferably on the beam tube exterior of the prism system. Of course, for applications in high vacuum it can happen that, if it involves a polarization foil or the polarizer is attached by cementing on the prism system, the vacuum is affected negatively. In this case the polarizer is attached preferably to the beam tube interior.
Depending on the geometric features of the vacuum chamber, it can be necessary to design the beam tube of the vacuum adapter with a minimum cross section or curved. For these cases the beam tube of the vacuum adapter has advantageously deflecting prisms to guide the beam.
For the quality of the measurement results an accurate finding of the position of the sample in relation to the measurement beam is advantageous. To this end, the measurement system, disposed in the device of the invention, exhibits not only a measuring unit, which can be, for example, an ellipsometer, a reflectometer or a FTIR spectrometer but also an adjusting unit. The adjusting unit comprises at least one light source and at least one position sensitive detector. Preferably an adjusting laser is installed as the light source. Due to the installation of, for example, beam splitters, a light source, which may or may not also be present in the measuring unit, can be used simultaneously for the adjusting unit. The beam plane of the adjusting unit is moved parallel to the measurement geometry so that the system""s state of adjustment can be reproduced as correctly as possible.
In an especially preferred embodiment a triangulation configuration is used as the adjusting unit. Thus, both the sample spacing and the tilt can be measured automatically. In this case the adjusting unit comprises an adjusting laser, a beam splitter and two position sensitive detectors. The laser beam from the adjusting laser is split by means of the beam splitter into two beams that are moved so as to be parallel. The one beam is used to determine the sample spacing. When the spacing between the samples changes, the point of impingement on the sample surface and thus also the reflected beam""s point of impingement on one of the position sensitive detectors moves. The deviation from the desired value can be determined electronically and, if desired, can be used for an automatic correction by means of the servomotors. To determine the sample tilt, the second partial beam is used. When the sample tilts, this beam migrates to the second position sensitive detector, a state that can be determined in turn electronically. The tilt of the sample can be corrected mechanically, or the angle of tilt can be determined quantitatively and then taken into consideration during the evaluation of the measurement.
For tests, in which not only one point but also several points on the sample have to be measured, it has proved advantageous to use rotating sample tables. Between two measurements the sample can be further rotated about a specific angle by means of the rotating table. Preferably the rotating table is disposed on a linear table.
The linear table""s direction of movement is in the radial direction of the rotating table. Through a combination of translational and rotational motions, an even greater number of measurement points can be approached on the sample surface. Especially compact is a variant, where not the rotating table is disposed on a linear table, but deflecting prisms or mirrors are spaced at a specific distance from the rotating table so that they can be moved linearly in the radial direction of the rotating table. Through a combination of linear movements of the about the prisms or mirrors and the rotating movements of the rotating table, just as many measurement points can be approached as in the embodiment described above. [sic]
The device, according to the invention, exhibits many advantages. Since the inventive device permits the integration of the measurement process into the production process in that it is carried out between the process steps and there is no need for the sake of adjustment to intervene in the operating mode of the production system, the goal is reached, on the one hand, that the samples can be measured extremely process oriented and, on the other hand, that the measurements can be carried out in such a manner that production and measurement do not exert a mutual negative effect. At this stage it is now possible to measure arbitrary samples without disturbing the production process and to achieve thereby maximum measurement accuracy. Eliminated are the cost intensive intermediate paths between the individual process steps and the measurement and, above all, the long reaction time between the detection of production errors and the reaction thereto.
Since the measurement configuration or the measurement geometry can be uncoupled from the design of the measurement system by means of the vacuum adapter, the measurement system can be optimized for higher measurement accuracy in an economical design. In addition, the entire device can be easily adapted to the space conditions in already existing production systems. To retrofit already existing production plants, it suffices to introduce the vacuum adapter into the vacuum through an opening in the respective vacuum chamber.
Since the measurement system is not located under vacuum, maintenance work and retrofitting work can be done on the measurement system without having to ventilate the process line or the respective vacuum chamber. Even the expense of building the measurement system decreases, since it is not necessary to use vacuum appropriate components, such as cable ducts. In addition, the negative effect on the volume in the sample or measurement surroundings, for example, due to the electrical components is prevented.
Several devices of the invention can be integrated in such a manner at diverse points of the production process that they are adapted to the production process of the respective product. Since the retrofitting of the production systems with the inventive device is associated with little cost and the inventive device itself is economical due to its simple construction, there is the possibility of setting up a comprehensive quality control system inside the production process at a low investment cost.


A belt spool for a belt retractor comprises a torsion rod and a spool body that has a recess in which is provided a shaped part by means of which an end of a safety belt can be fastened in the recess. The shaped part rests at the torsion rod in order to be supported when the shaped part is stressed by a tensile load of the safety belt. There is also proposed a belt retractor including such a belt spool.

The invention relates to a belt spool for a belt retractor, comprising a torsion rod and a spool body that has a recess in which is provided a shaped part by means of which an end of a safety belt can be fastened in the recess. The invention also relates to a belt retractor comprising such a belt spool.
DE 296 05 115 discloses such a belt spool in which the shaped part is supported on the recess in the body of the belt spool Therefore, the spool body of the belt spool has to be stable enough to be able to absorb the tensile load of the safety belt.
It is the object of the invention to provide a simple and lightweight belt spool.
According to the invention, a belt spool for a belt retractor comprises a torsion rod and a spool body that has a recess in which is provided a shaped part by means of which an end of a safety belt can be fastened in the recess. The shaped part rests at the torsion rod in order to be supported when the shaped part is stressed by a tensile load of the safety belt. In this manner, the torsion rod can absorb the tensile load of the safety belt. However, the spool body of the belt spool no longer has to be as stable as a spool body that has to withstand the entire tensile load of the safety belt. This results in considerable weight savings since, first of all, a lighter material can be used for the spool body and secondly, a smaller diameter can be selected for the spool body
According to a preferred embodiment, the torsion rod has two hub sections with which it engages the spool body, and an axle section that connects the two hub sections to each other, the shaped part being only supported on the torsion rod at the hub sections. In this manner, the tensile load of the safety belt is only applied to the torsion rod at the hub sections, so that the torsion rod is prevented from bending, which would impair the primary function of the torsion rod, namely, to delimit the belt force. Via the hub sections, however, the torsion rod can transfer the load to the belt spool with a relatively short path, and from here, the force is absorbed by the bearings of the housing of the belt retractor.
Moreover, the invention proposes a belt retractor comprising a safety belt and an above-mentioned belt spool, an end of the safety belt forming a loop that surrounds the shaped part. Such a belt retractor can be made smaller since the space requirement for the wound-up belt is reduced in the case of a belt spool the spool body of which has a smaller diameter.
Additional advantageous embodiments of the invention will be apparent from the subordinate claims.

TRW Occupant Restraint Systems GmbH and Co. KG


A sealing material of the present invention is a sealing material for sealing a metal material, including 70 mass % to 100 mass % of glass powder including alkali silicate glass and 0 mass % to 30 mass % of ceramic powder, and having a linear thermal expansion coefficient in a temperature range of from 30° C. to 380° C. of more than 100×10−7/° C. and 170×10−7/° C. or less.

A hermetic terminal of a refrigerant compressor is produced by sealing a metal stem and a metal pin to each other with a sealing material in order to maintain hermetic reliability.
The sealing material is produced and used as described below. First, a glass raw material is melted and formed, and the resultant formed body is pulverized in a ball mill and then allowed to pass through a predetermined sieve to provide fine powder. Next, granules are produced by mixing the fine powder with a binder and granulating the mixture. In some cases, the granules are obtained by adding and mixing ceramic powder to glass powder and granulating the resultant composite powder. After that, the resultant granules are subjected to tablet molding to produce a green compact having a through-hole, and the green compact is increased in temperature from normal temperature, to thereby decompose and remove the binder and sinter the green compact. Next, a metal pin is inserted in the through-hole of the resultant sintered compact, and the sintered compact is in turn housed in a circular metal stem, followed by being loaded into a firing furnace, and fired at a temperature higher than a glass transition point under an inert atmosphere or a nitrogen atmosphere, to thereby seal the metal pin and the metal stem to each other. As a result, the sealing material is in a state of being compressed by the metal stem. The metal stem generally has a linear thermal expansion coefficient of 140×10−7/° C. The metal, pin generally has a linear thermal expansion coefficient of from 100×10−7/° C. The sealing material generally has a linear thermal expansion coefficient of from 89×10−7/° C. to 95×10−7/° C.
FIG. 1A is a conceptual diagram for illustrating a hermetic terminal 1. The hermetic terminal 1 comprises a metal stem 11, a metal pin 12, and a sealing material 13. FIG. 1B is a conceptual diagram for illustrating, with respect to a main portion of the hermetic terminal 1 of FIG. 1A, a state of the metal stem 11, the metal pin 12, and the sealing material 13 before firing. FIG. 1C is a conceptual diagram for illustrating, with respect to the main portion of the hermetic terminal 1 of FIG. 1A, a state of the metal stem 11, the metal pin 12, and the sealing material 13 after the firing.


A fuel injector control system including a fuel injector, a sensing device configured to provide a transition signal indicative of a fuel injector transition from the closed-state to the open-state, and a controller configured to determine an injector control signal based on the transition signal. The injector control signal closing time can be adjusted base on the transition signal and so compensate for injector opening delay due to, for example, a stuck closed fuel injector, cold temperatures, or low injector drive voltages.

Fuel injectors in internal combustion engines are generally operated by alternately switching the fuel injector between a closed-state where no fuel is dispensed by the fuel injector, and an open-state where fuel is dispensed by the fuel injector. It has been observed that some fuel injectors may stick and remain closed for an indefinite period of time after a signal to open the fuel injector has been applied to the fuel injector. This problem is particularly evident if it is the first time the injector is being opened after being in the closed-state for an extended period of time, for example, when a vehicle is parked over-night with the engine off. It has been observed that certain injector designs, such as compressed natural gas (CNG) injectors that use an elastomer to better seal a pintle/seat interface, are more susceptible to sticking than metal-to-metal type seals. Also, it has been observed that some fuel injectors are more susceptible to sticking if the ambient temperatures are relatively low, for example less than −20 degrees Celsius. If a fuel injector does not transition from the closed-state to the open-state predictably, the amount of fuel dispensed by the injector may be uncertain.

Fuel injector control system and method to compensate for injector opening delay