A bearing for a gearbox, the bearing having a cylindrical body. The cylindrical body defines a hollow interior chamber. The cylindrical body has a gear supporting section. The gear supporting section has a cross-section formed by three lobes equally distributed around a circumference of the cylindrical body. Each of the lobes has a land portion having a first radius over at least 20% of the lobe. Each lobe also has a tapered portion that gradually slopes from the first radius of the land portion to a reduced radius region that is smaller than the first radius. The tapered portion is formed over less than 80% of each lobe. Each lobe also has an opening formed in the reduced radius region and a flow passage fluidly connecting the hollow interior of the cylindrical body with the opening formed in the reduced radius region.

Gas turbine systems include a rotor unit mounted to rotate inside a stationary external housing and generally have a gearbox that is mounted at one end of the gas turbine engine. The gearbox is generally positioned adjacent the turbine engine and coupled in a manner to use power from the gas turbine engine to drive the gas turbine engine's accessories such as electrical generators, fluid pumps, and heat exchangers for cooling oil or heating fuel. The gearbox includes a several interlocking gears rotating on oil bearings. During operation of the gas turbine engine and the gas turbine engine's accessories, sub-synchronized vibrations can develop due to fluid-structure coupling between torsional and linear vibrations inside the rotating components of the gas turbine engine and gas turbine engine's accessories.
U.S. Patent App. Pre-Grant Publication No. 2009/0148084 to I. Komori et al. discloses a fluid dynamic bearing device equipped with a shaft member of high strength. The bearing device is disclosed as being capable of maintaining high bearing performance at low cost. The bearing device has a shaft member equipped with a shaft blank and a resin portion. The shaft blank has, as an integrated unit, a shaft part formed of a material of a higher strength than resin, and a protruding part protruding radially outwards from the shaft part. The resin portion covers at least one end surface of the protruding part of the shaft blank and faces a thrust bearing gap.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors or that is known in the art.


Significant improvement is achieved in the analysis of IC layout by utilizing the fact that IC designs exhibit a large amount of regularity. By employing a unique mesh generation approach that takes advantage of the regularity, combined with the use of a limited number of different shapes for the majority of the IC geometry greatly increases the speed of processing. Additionally, by employing a unique approach for specifying the different mesh elements—based on the parameters that define the relative difference between one shape and another—provides significant additional reductions in the necessary calculations, and a corresponding increase in speed of IC simulations. Yet another improvement is realized by simplifying the inductive influence calculations by employing averages that permit using dot products of vectors rather than integrations of non-constant vectors.

This invention pertains to integrated circuit (IC) simulations, and more particularly to methods for accurately simulating the behavior of integrated circuits.
Current day integrated circuits often contain millions of electronic elements within a single chip. The internal structures of these electronic elements are in the sub-micron range, and some of these ICs operate at very high frequencies. Consequently, accurate simulations of the IC designs are essential.
Some tools already exist in the computer aided design (CAD) community for digital extraction and simulation of ICs, and these tools are being adapted for high-speed design. However, these tools often incorrectly model the physical effects, and the accuracy of their results is deficient to the point that they cannot be used for practical designs. This is illustrated in FIG. 1, where IC layout information is provided to computer 1 wherein a computer aided design (CAD) simulation software 2 interacts with software 3 that models the behavior of the IC elements specified in the layout, and results of the simulation are outputted. The method executed in the FIG. 1 prior art system is shown in FIG. 2. Tools also exist in the microwave community, and these tools are reasonably accurate because they account for both the first-order and second order effects (e.g., interaction of components that are not physically connected to each other) using Maxwell equation formulations.
Basically, the way these tools tackle the problem is by subdividing a given structure of conductive materials into a mesh of interconnected, elemental, three-dimensional shapes that are small enough to precisely subsume the given structure and to yield accurate calculations relative to their interactions. FIG. 4 illustrates multi-layer arrangement of conducting elements that includes a coil 12 at the lower layer, and a collection of leads 11 at the upper layer. With a subdivision of the structure into a collection of elemental pyramids structures such as shown, for example, in a portion of FIG. 4, a solution is obtained by use of numerical methods and precise mathematical representation of the interaction between each of the elemental three-dimensional shapes and all other of the elemental three-dimensional shapes.
The notion of subdividing the given structure into a mesh of elemental three-dimensional shapes and then performing calculations pertaining to those shapes is not unlike the concept used in teaching the principles of integration by, for example, illustrating that when a two-dimensional figure like a circle is divided into small elemental geometric shapes (e.g., squares), the sum of the areas of the small elemental geometric shapes approximates the area of the circle, and that the approximation improves as the size of the small elemental geometric shapes is reduced.
While in mathematical integration the elemental geometric shape when dealing in three dimensions is a cube (dx, dy, dz) that diminishes to infinitesimal size, in FIG. 5 the small elemental geometric shape is a pyramid that is more than infinitesimal in size, albeit, significantly smaller that than the smallest discernable element in the IC's layout. Also unlike the mathematical approach of integration, the simulation art employs elemental shapes (such as the pyramids of FIG. 4) of different sizes and perhaps even of different shapes, so as to create an accurate representation of the physical structure and yet not use an inordinately large number of pyramids. This is possible to achieve because all dimensions in an integrated circuit layout are discrete. Still, the existing tools are extremely slow, and their memory requirements are excessive.

Efficient large-scale full-wave simulation


The servovalve with torque motor consists of a cylindrical case (3) in which an armature (1) is arranged on one end of an arm (16) and a orifice (18) closing a nozzle (19) with working liquid (2) on the other side of the arm (16). The arm (16) is free to rotate round the pivot point of a flexible suspension (15) with a hole (21) of diameter corresponding to the maximum deflection of the arm (16). There are two magnetic pole shoes (5) and two electric pole shoes (4) located around the armature (1), equipped with sealing rings (6), and so the working liquid (2) filling the inside of the case (3) and surrounding the arm (16) and the armature (1) does not leak out of the inside space. Coils (7) are located outside the case (3). The pole shoes (4, 5) are equipped with threaded parts (12), fitting either into the outer ring (10) or the body (3). The magnetic pole shoes (5) are equipped with a non-magnetic protective housing (9). The servovalve solution minimizes flow of the working liquid (2) through the electromagnetic circuit area, separates this area from the working liquid (2) and facilitates adjustment of the torque motor characteristics. The servo valve is suitable for high pressures.

The invention deals with a servovalve with a torque motor with mechanical characteristic adjustment, particularly suitable for high pressure levels. The torque motor consists of a square or rectangle cross-section armature surrounded by four pole shoes, two of which are pole shoes with permanent magnets of high energy density located against each other, and the other two are electric pole shoes with exciting coils, also facing each other, but positioned by 90° to the magnetic ones. All the pole shoes are located on the other side than the armature in an outer ring thread, which thus closes the magnetic field. The existing solutions of torque motors of servovalves have to deal with two basic problems, namely separation of working liquid from the servovalve electromagnetic circuit, and then adjustment of the torque motor electromagnetic circuit.
Separation of the liquid area from the electromagnetic circuit of the servovalve is usually solved by sealing integrated in the torque motor armature attachment. There are two solutions. In the first one the attachment consists of a flexible thin-walled tube, the wall of which separates the work medium space from the electromagnetic part of the torque motor. In the other one the attachment consists of a thin flexible sheet, while a static sealing (an O-ring) is installed in the armature rotation axe, and the armature goes through the sealing. However these solutions are not suitable for higher pressure levels of several MPa.
Another solution with the magnetic circuit inundated in the work medium has to be used for high pressures. Actually it is necessary to use specially impregnated coils and to seal wires going through the case of the product.
Adjustment of torque motors is necessary for achieving the required armature stroke characteristic in relation to the controlling signal, mostly electric current. For manufacturing purposes each product has to be finely adjusted to the required characteristics, which have to be quite precise. The existing solutions usually change the electromagnetic power by changing magnetization of the permanent magnets in the electric circuit. This solution requires use of magnets, which can be magnetized and demagnetized. However these magnets are always bigger and heavier than those made of rare soils, which are magnetized from manufacturing and have high energy density relative to a volume unit. In some instances the torque motor characteristic pattern has to be modified, which can only be achieved by different distance between the armature and the pole shoes, which however requires to dismantle the torque motor, insert inlets or grind off the pole shoes.
The above reasons call for providing a solution of a torque motor that could cope with work medium pressures of up to several MPa with no impact on the operation or life cycle of the servovalve components.
It is then necessary to find a torque motor design enabling adjustment of torque motor characteristics without having to dismantle it, modify its parts or magnetize the permanent magnets.
Finally we should find such a solution of torque motor that uses permanent magnets of rare soils which have high energy density, which can reduce dimensions and weight of the motor.
The primary task of the invention is thus to develop a servovalve with electromagnetic torque motor mentioned in the introductory section, where the new solution separates the work liquid area from the servovalve electromagnetic circuit and facilitates adjustment of the servovalve. The next task of the invention is to minimize the work liquid flow in the area of the electromagnetic circuit. The first task is solved by a solution consisting except others of the above mentioned magnetic pole shoes, an outer ring, a coil and an armature. The servovalve with torque motor consists of the known cylindrical case, in which the armature is situated on one end of an arm, and the orifice closing the nozzle on the other end of the arm, while the arm is free to rotate around a pivot point of a flexible suspension, and there are two magnetic pole shoes and two electric pole shoes with coils positioned by 90° against the first ones, around the armature inside the cylindrical case. The invention principle is based on the fact that the arm with the armature are surrounded by the working liquid, which fills in the inside of the cylindrical case, the pole shoes are fitted with sealing rings on their ends protruding inside the cylindrical case, and the coils are placed outside the case, i.e. outside the area filled in with the working liquid.
In one advantageous modification of the pole shoes attachment the pole shoes are equipped with a threaded part with male thread on their ends oriented from the armature, fitting to the female thread of the outer ring fitted on the cylindrical case.
In another advantageous modification of the pole shoes attachment the pole shoes are equipped with a threaded part with male thread on their ends oriented from the armature, passing through the outer ring and fitting to the female thread cut in the cylindrical case.
In another advantageous modification of the invention the pole shoes are equipped with an axial housing made of non-magnetic material.
The main advantage of the solution of an electromagnetic servovalve with a torque motor according to the invention is, that it enables the servovalve to operate in operation pressures of up to tens of MPa, while the working liquid is separated from the coils and adjustment points of the torque motor.
Another advantage of the solution of an electromagnetic servovalve with a torque motor according to the invention is, that the servovalve characteristics may be simply adjusted by turning the individual pole shoes and thus changing their distance from the armature.
Another advantage of the solution according to the invention is the possibility to use permanent magnets with high energy density, and these magnets do not have to be re-magnetized during adjustment.
The second task of the invention, namely restriction of working liquid flow through the electromagnetic circuit area is solved by the advantageous servovalve solution according to the invention, where the diameter of the hole in the flexible suspension through which the armature arm goes is not bigger than necessary for enabling the required deflection of the armature arm.
The advantage of this servovalve solution is in limitation of the working liquid flow near the armature and the pole shoes to the minimum, which prevents possible impacts on the electromagnetic field and accumulation of magnetic impurity near the armature and the pole shoes.


A valve actuator apparatus is provided, which further comprises a linkage mechanism, which can convert rotational force into translational force. This linkage mechanism also imparts a much greater degree of mechanical advantage than typical rack-and-pinion linkages allowing either for greater closing force on the valve or for the use of smaller drive motors to actuate the valve. Furthermore, this linkage mechanism can lock the valve closed, with full seating force, even when no torque is provided by a drive motor.

In recent years, there has been an increasing demand for electrically-driven actuation of valves, particularly for those valves controlling heating media in rapid-response water heaters. Electric valve actuators have many advantages over pneumatic or hydraulic valve actuators. Specifically, electrically actuated valves consume small amounts of ordinary electric energy, as opposed to costly compressed air or hydraulic pressure. Also, precision, strength and reliability are equal to or better than alternative operating media, and their electronic circuitry can interact directly with computerized building controls.
A disadvantage associated with electrically-driven actuators, particularly those with close ratio (high-speed) gear trains, is that most do not maintain a sufficient holding torque when de-energized. The problem lies with the rack-and-pinion linkage systems, which are generally used in conjunction with electric valve actuators. For more information regarding the use of rack-and-pinion linkage components with valve actuators see, for example, U.S. Pat. No. 4,597,556 which is incorporated herein by reference in its entirety. As a general rule, these linkage systems can transmit force equally well in both directions, which can allow pressure from within a valve to move the gear-train, including the rack-and-pinion linkage, backward reducing the amount of seating force applied to the valve. The reduction in seating force can allow undesired flow through the valve to occur. In the case of rapid response water heaters, this undesired flow can allow overheating of the hot water supply, which can lead to scalding.
The current solution to this problem has been to increase the stroke length of the actuator linkage which reduces the mechanical advantage imparted by the rack-and-pinion linkage. The benefit being that although it would require more force to close the valve, it would also require more pressure from within the valve to force the gear-train of rack-and-pinion linkage backward, re-opening the valve when the electric actuator is de-energized. Similarly, the size of the electric drive motor used to operate the valve actuator can also be increased, increasing the inertial mass of the actuator, which further increases the force required to drive the gear train, including the electric motor, backwards. However, these measures are not ideal solutions to the problem because both are only partially effective at preventing unwanted valve opening. Additionally, increasing the stroke length of the actuator linkage and increasing the size of the electric motor will decrease the efficiency and compactness of the valve actuator.
What is needed is a valve linkage apparatus capable of producing a large output force from a small input torque while also being capable of precisely positioning the internal control elements of a valve. Furthermore, the valve linkage apparatus would preferably be able to maintain a valve in its closed position, with full seating force applied, even when all external sources of operating energy are unavailable to the valve actuator.

Actuator apparatus for operating and locking a control valve and a method for its use


A bottom friction feeder comprises a material magazine assembly, a gate assembly including a guide subassembly and a singulation gate subassembly, a back wedge assembly, and a bottom friction belt assembly.

1. Field of the Invention
The present invention relates, generally, to automated materials handling machinery. Particularly, the invention relates to automated machinery for feeding material into a related machine or system. Most particularly, the invention relates to friction feeder machinery.
2. Background Information
Bottom Friction Feeders are used throughout the graphics, mailing and packaging industries. They are used to feed product from a stack. Bottom Friction Feeder technology is utilized by a number of companies.
The existing technology includes that disclosed in U.S. Pat. Nos. 5,967,507, 5,476,255 and 5,255,905. These patents relate to top sheet feeders.
A need exists for the present invention.
All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.


A process and apparatus for providing a piston travel indicator for a railroad brake includes coating the components of the brake assembly with a powder. The powder coating may include an epoxy, a polyester or combinations thereof. After the selected components of the railroad car brake assembly are sprayed with the powder, the components are heated in an oven for curing the powder to form a coating on the components. The coating may be applied in dual or multiple colors to the railroad car brake components. A piston travel indicator on the hollow rod is provided by coating the hollow rod of the piston with more than one color at specific intervals for enabling a person to visually observe the colors for determining the travel of the hollow rod and indicating if the brake is functioning properly.

The invention relates to powder coating and, more particularly, to the coating of railroad car brake assembly components.
Powder coating is used in various industries as a finishing technology for producing a high quality and durable finish while maximizing production, reducing costs, improving efficiency, and complying with environmental regulations. Powder coating is currently used on products such as appliances, building materials, electrical components, and furniture.
A railroad car has brake assemblies for controlling the speed of the railroad car along the railroad tracks. Each brake assembly of the railroad car includes numerous components which cooperatively work together, and are formed of various materials, such as cast iron, cast steel, aluminum and spring steel. After extended periods of use, such as the extensive miles traveled by a railroad car, the components of the railroad car brake tend to show wear, corrosion, abrasion or the like, requiring repair or replacement of some of the components of the railroad car brake or the entire railroad car brake assembly.
Currently, the piston tube is anodized. However, when the piston tube is subjected to certain conditions, such as salt or ultraviolet light, the anodized coating tends to break down.
Additionally, to determine how far the hollow rod of the piston extends from the brake cylinder, a person must crawl under the railroad car and measure the distance. The distance that the hollow rod extends from the cylinder is used for determining if the brake is working properly.
Therefore, what is needed is a method for improving the performance and extending the life of the railroad car brake assembly which involves coating components of the railroad car brake assembly with a powder coating.

Process for providing a piston travel indicator for a railroad car brake assembly


In order to gather, store temporarily and deliver (if needed) central processor safestore information, a multiphase clock is employed to capture (one full clock cycle behind) the safestore information which typically includes all software visible registers in all (or selected) data manipulation chips of the CPU by routing the safestore information through temporary storage (under the influence of the multiphase clock) in a cache data array and into a special purpose XRAM module. Thus, upon the sensing of a fault, valid safestore information is available in the XRAM for analysis and, if appropriate, resumption of operation at a sequential point just previous to that at which the fault occurred.

In the design of a mainframe CPU, it is highly desirable to provide powerful and reliable error detection and handling features, and this requirement has mandated the provision of various circuits, firmware and software to sense and resolve the diverse types of errors which may occur in operation. When a fault is sensed, it is often necessary to abort an operation in process since the result cannot be trusted. If the fault source is corrected, or if it is determined to have been the result of a transient condition, processing may be resumed, but must do so at a point in the processing operation prior to the operation which resulted in the fault. Thus, it is well known to provide for the temporary storage of a "safestore frame" which contains the essential information necessary to effect a resumption of processing. This essential information typically includes the results of the execution of an ascertainable instruction preceding the fault and may include supplementary information such as the contents of various registers in the processing unit at that time.
In one CPU configuration in which the present invention finds use, certain chips in a Basic Processing Unit (BPU) are provided in master/slave pairs with the results of data manipulation in the BPU being compared for identity. During the data manipulation, safestore information (e.g., the software visible registers in the chips which are active in the current operation) is accessible on master and slave result busses which also serve to supply the execution results from each instruction for comparison to error sensing circuitry. Consequently, there is the opportunity, after the occurrence of a fault and a decision to resume, to return execution to the same or a different CPU at an operation point immediately preceding that at which the fault was sensed.

Safestore frame implementation in a central processor


Systems and methods are provided for coordinating power management for wireless communications devices in an independent basic service set (IBSS). An announcement traffic indication message (ATIM) coordinator receives address information for destination stations for which data is buffered for transmission at source stations. The ATIM coordinator sends an ATIM Indication frame at the end of an ATIM window, alerting any destination station to remain awake to receive buffered data. Source stations may enter power save mode during the ATIM window after transmitting the address information for the destination stations to the ATIM coordinator. Destination stations may enter power save mode after receiving a beacon at the start of the ATIM window. Source and destination stations may awaken at the end of the ATIM window to receive the ATIM Indication frame.

Wireless local area networks (WLANs) conforming to specifications in the Institute of Electrical and Electronics Engineers ("IEEE") 802.11 family typically involve an infrastructure-based network topology such as a basic service set (BSS) or an ad hoc-based network topology such as an independent basic service set (IBSS). While a BSS may be managed by a device acting in the role of an access point (AP), management functions in an IBSS are distributed among the participating devices. One important area associated with network management is the implementation of power management techniques that allow a device to enter a power save mode of operation, during which it may be able to conserve battery resources, but may not be able to receive or transmit communications. Such techniques may be more challenging in an ad hoc network due to the lack of a dedicated management device, such as the AP.
To that end, power management for stations operating in an IBSS may be coordinated through the use of announcement traffic indication messages (ATIMs) that are exchanged during a defined period of time known as the ATIM window that immediately follows the target beacon transmission time (TBTT). Conventionally, all stations in the IBSS awaken prior to the TBTT in order to receive the beacon transmission and stay awake at least for the duration of the ATIM window. Accordingly, a station may send an ATIM frame within the ATIM window to indicate the presence of buffered data that is pending transmission to one or more other stations. Upon receipt of an ATIM frame identifying it, a station may then remain in active mode through the current beacon interval in order to receive the buffered data. Likewise, the station having buffered data also remains in active mode to transmit the data during the current beacon interval.
As will be appreciated, this conventional scheme results in all stations in the IBSS remaining in active mode for the duration of the ATIM window. Further, any station that will be transmitting or receiving buffered data remains in active mode for the current beacon interval and at least the subsequent ATIM window. Thus, considerable power is expended by the stations in order to operate in active mode for the ATIM windows and additional power may be consumed when buffered data is to be exchanged.
Accordingly, it would be desirable to provide systems and methods for coordinating power management among devices in an IBSS that allow a reduction in power consumption while coordinating the exchange of buffered data. This disclosure addresses these and other needs.

Systems and methods for coordinating power management in an independent basic service set


An ultrasound imaging method employs an ultrasound transducer which outputs a beam that is scanned along a scan plane. The transducer is controllable to move the scan plane to plural non-coplanar orientations. The imaging method comprises the steps of: operating the ultrasound transducer to acquire and store data indicative of an ultrasound image in each of a plurality of scan planes that are non-coplanar. For each ultrasound image that is acquired in a scan plane that is non-coplanar with a reference scan plane, the ultrasound image is transformed by performing a projection of the non-coplanar scan plane and its image data onto the reference scan plane. The projected non-coplanar ultrasound image is then displayed by employing the projection data indicative of the image.

Many modern ultrasound systems employ phased array transducers which comprise a number of individual transducers that are arranged, side by side, in a unitary assembly. In effect, the phased array of transducers acts like an acoustic lens with an electronically variable focal length. Such a phased array transducer, while stationary, is electronically controllable to steer and focus an ultrasound beam so as to achieve a B scan image.
B or brightness mode scanning is the most common type of ultrasound imaging. A B scan is a view of a cross-sectional slice through the object being imaged. A narrow pencil beam of ultrasound energy is swept through a scan sector to define a scan plane. The beam is formed from bursts of ultrasound and the repetition rate of the ultrasound pulse generation is selected so that the transmitted pulse has time to travel to the deepest target and back again before the next pulse is launched. The echoes vary in intensity according to the type of tissue or body structure causing the echoes. The echo return data is presented on a display in which the brightness depends upon the echo strength.
In addition to a phased array being able to provide an image in a single scan plane, certain phased array transducers are rotatable about an axis that is orthogonal to the transducer's emitting face. The rotation of the phased array structure enables the scan plane to be rotated about the orthogonal axis and thus enables multiple images to be acquired at various rotated scan plane orientations.
In addition to phased array ultrasound transducers, other types of ultrasound probes also are adapted to generate multiple image planes, I. e., "wobbler" probes, tomographic-type probes which produce multiple parallel planes at known spatial intervals, etc. Each of the abovementioned probes enables acquisition of more than one, two-dimensional ultrasound image without requiring a physical movement of the entire probe housing.
Ultrasound scanners typically display a two dimensional B scan image as a sector (or other geometrical shape) on a display screen. Although the image data within the sector changes as the transducer is moved and different areas of tissue are scanned, the sector shape, itself, remains constant regardless of transducer orientation. Further, when the scan plane of a rotatable phased array ultrasound probe is changed, the prior art display presents an identical sector scan as for all other scan planes.
A further indicator is sometimes provided on the display which informs the operator of the angular sensor position with respect to the tip of the ultrasound transducer. Such indicator may be an angle icon. The user is then forced to conceptualize the orientation of the scan plane in three-dimensional space and, in particular, in a three-dimensional position that is relative to other image planes acquired at the same probe tip position, but using different sensor angles. Such visualization on the part of the user requires substantial training and is still subject to error if, for any reason, the user is distracted during the ultrasound examination.
Thus, there is a need for an improved imaging method for multiplanar ultrasound images which enables the user to better visualize three dimensional objects that are scanned using multiple non-coplanar scan planes. There is further need for an improved ultrasound imaging method which enables a quasi-three dimensional viewing of scan planes that are non-coincident with a reference scan plane.

Method and apparatus for display of multi-planar ultrasound images employing image projection techniques


Poinsettia "H-29" is a new cultivar, distinguished by peach pink bracts and unique flower bract formation and presentation. "H-29" is a seedling from cross pollination. The new plant produces a very desirable flowering pot plant. The post-production foliage and bract retention is excellent even under low light intensities in the consumer's home.

This new poinsettia cultivar, "H-29," originated as a seedling from cross pollination in my greenhouse in Encinitas, Calif., and was selected because of its unusual flower bract color, bract formation and bract presentation; traits which distinguish it from other poinsettia cultivars, and seem to make it a desirable plant for commercial greenhouse production. After selection, "H-29" was vegetatively reproduced from stem cuttings for test purposes in Encinitas, Calif. By subjecting clones of this plant to successive generations of vegetative propagation, it was demonstrated that the distinctive characteristics of "H-29" held true from generation to generation.


The invention provides methods and compositions relating to IKAP proteins which regulate cellular signal transduction and transcriptional activation, and related nucleic acids. The polypeptides may be produced recombinantly from transformed host cells from the disclosed IKAP encoding nucleic acids or purified from human cells. The invention provides isolated IKAP hybridization probes and primers capable of specifically hybridizing with the disclosed IKAP genes, IKAP-specific binding agents such as specific antibodies, and methods of making and using the subject compositions in diagnosis, therapy and in the biopharmaceutical industry.

Cytokines trigger changes in gene expression by modifying the activity of otherwise latent transcription factors (Hill and Treisman, 1995). Nuclear factor .kappa.B (NF-.kappa.B) is a prominent example of how such an external stimulus is converted into an active transcription factor (Verma et al., 1995). The NF-.kappa.B system is composed of homo- and heterodimers of members of the Rel family of related transcription factors that control the expression of numerous immune and inflammatory response genes as well as important viral genes (Lenardo and Baltimore, 1989; Baeuerle and Henkel, 1994). The activity of NF-.kappa.B transcription factors is regulated by their subcellular localization (Verma et al., 1995). In most cell types, NF-.kappa.B is present as a heterodimer comprising of a 50 kDa and a 65 kDa subunit. This heterodimer is sequestered in the cytoplasm in association with I.kappa.B.alpha. a member of the I.kappa.B family of inhibitory proteins (Finco and Baldwin, 1995; Thanos and Maniatis, 1995; Verma et al., 1995). I.kappa.B.alpha. masks the nuclear localization signal of NF-.kappa.B and thereby prevents NF-.kappa.B nuclear translocation. Conversion of NF-.kappa.B into an active transcription factor that translocates into the nucleus and binds to cognate DNA sequences requires the phosphorylation and subsequent ubiquitin-dependent degradation of I.kappa.B.alpha. in the 26s proteasome. Signal-induced phosphorylation of I.kappa.B.alpha. occurs at serines 32 and 36. Mutation of one or both of these serines renders I.kappa.B.alpha. resistant to ubiquitination and proteolytic degradation (Chen et al., 1995); DiDonato, 1996 #370, Roff, 1996 #397.
The pleiotropic cytokines tumor necrosis factor (TNF) and interleukin- 1 (IL-1) are among the physiological inducers of I.kappa.B phosphorylation and subsequent NF-.kappa.B activation (Osborn et al., 1989; Beg et al., 1993). Although TNF and IL-1 initiate signaling cascades leading to NF-.kappa.B activation via distinct families of cell-surface receptors (Smith et al., 1994; Dinarello, 1996), both pathways utilize members of the TNF receptor-associated factor (TRAF) family of adaptor proteins as signal transducers (Rothe et al., 1995; Hsu et al., 1996; Cao et al., 1996b). TRAF proteins were originally found to associate directly with the cytoplasmic domains of several members of the TNF receptor family including the 75 kDa TNF receptor (TNFR2), CD40, CD30, and the lymphotoxin-.beta. receptor (Rothe et al., 1994; Hu et al., 1994; Cheng et al., 1995; Mosialos et al., 1995; Song and Donner, 1995; Sato et al., 1995; Lee et al., 1996; Gedrich et al., 1996; Ansieau et al., 1996). In addition, TRAF proteins are recruited indirectly to the 55 kDa TNF receptor (TNFR1) by the adaptor protein TRADD (Hsu et al., 1996). Activation of NF-.kappa.B by TNF requires TRAF2 (Rothe et al., 1995; Hsu et al., 1996). TRAF5 has also been implicated in NF-.kappa.B activation by members of the TNF receptor family (Nakano et al., 1996); Ishida, 1996 #240. In contrast, TRAF6 participates in NF-.kappa.B activation by IL-1 (Cao et al., 1996b). Upon IL-1 treatment, TRAF6 associates with IRAK, a serine-threonine kinase that binds to the IL-1 receptor complex (Cao et al., 1996a); Huang, 1997 #400.
The NF-.kappa.B-inducing kinase (NIK) is a member of the MAP kinase kinase kinase (MAP3K) family that was identified as a TRAF2-interacting protein (Malinin et al., 1997). NIK activates NF-.kappa.B when overexpressed, and kinase-inactive mutants of NIK comprising its TRAF2-interacting C-terminal domain (NIK.sub.(624-947)) or lacking two crucial lysine residues in its kinase domain (NIK.sub.(KK429-430AA)) behave as dominant-negative inhibitors that suppress TNF-, IL-1-, and TRAF2-induced NF-.kappa.B activation (Malinin et al., 1997). Recently, NIK was found to associate with additional members of the TRAF family, including TRAF5 and TRAF6. Catalytically inactive mutants of NIK also inhibited TRAF5- and TRAF6-induced NF-.kappa.B activation, thus providing a unifying concept for NIK as a common mediator in the NF-.kappa.B signaling cascades triggered by TNF and IL-1 downstream of TRAFs. Recently two NIK-interacting protein designated characterized as novel human kinase I.kappa.B Kinases, IKK-.alpha. and IKK-.beta. have been reported (Woronicz et al., 1997; Mercurio et al. 1997; Maniatis, 1997). Catalytically inactive mutants of IKK suppress NF-.kappa.B activation induced by TNF and IL-1 stimulation as well as by TRAF and NIK overexpression; transiently expressed IKK associates with endogenous I.kappa.B.alpha. complex; and IKK phosphorylates I.kappa.B.alpha. on serines 32 and 36.
Relevant Literature
Ansieau, S., et al. (1996). Proc. Natl. Acad. Sci. USA 93, 14053-14058. PA0 Baeuerle, P. A., and Henkel, T. (1994). Annu. Rev. Immunol. 12, 141-179. PA0 Beg, A. A., et al. (1993). Mol. Cell. Biol. 13, 3301-3310. PA0 Cao, Z., Henzel, W. J., and Gao, X. (1996a). Science 271, 1128-1131. PA0 Cao, Z., et al. (1996b). Nature 383, 443-446. PA0 Chen, Z., et al. (1995). Genes Dev. 9, 1586-1597. PA0 Cheng, G., et al. (1995). Science 267, 1494-1498. PA0 Connelly, M. A., and Marcu, K. B. (1995). Cell. Mol. Biol. Res. 41, 537-549. PA0 Dinarello, C. A. (1996). Biologic basis for interleukin-1 in disease. Blood 87, 2095-2147. PA0 Fields, S., and Song, O. -k. (1989). Nature 340, 245-246. PA0 Finco, T. S., and Baldwin, A. S. (1995). Immunity 3, 263-272. PA0 Gedrich, R. W., et al. (1996). J. Biol. Chem. 271, 12852-12858. PA0 Hill, C. S., and Treisman, R. (1995). Cell 80, 199-211. PA0 Hsu, H., Shu, H. -B., Pan, M. -P., and Goeddel, D. V. (1996). Cell 84, 299-308. PA0 Hu, H. M., et al. (1994). J. Biol. Chem. 269, 30069-30072. PA0 Lee, S. Y., et al. (1996). Proc. Natl. Acad. Sci. USA 93, 9699-9703. PA0 Lenardo, M., and Baltimore, D. (1989). Cell 58, 227-229. PA0 Malinin, N. L., et al. (1997). Nature 385, 540-544. PA0 Maniatis (1997) Science 278, 818. PA0 Mercurio et al.(1997) Science 278, 860. PA0 Mock et al. (1995). Genomics 27, 348-351. PA0 Mosialos, G., et al. (1995). Cell 80, 389-399. PA0 Nakano, H., et al. (1996). J. Biol. Chem. 271, 14661-14664. PA0 Osborn, L., et al. (1989). Proc. Natl. Acad. Sci. USA 86, 2336-2340. PA0 Rothe, M., Sarma, V., Dixit, V. M., and Goeddel, D. V. (1995). Science 269, 1424-1427. PA0 Rothe, M., Wong, S. C., Henzel, W. J., and Goeddel, D. V. (1994). Cell 78, 681-692. PA0 Sato, T., Irie, S., and Reed, J. C. (1995). FEBS Lett. 358, 113-118. PA0 Schindler, U., and Baichwal, V. R. (1994). Mol. Cell. Biol. 14, 5820-5831. PA0 Smith, C. A., Farrah, T., and Goodwin, R. G. (1994). Cell 76, 959-962. PA0 Song, H. Y., and Donner, D. B. (1995). Biochem. J. 809, 825-829. PA0 Thanos, D., and Maniatis, T. (1995). Cell 80, 529-532. PA0 Woronicz et al., (1997) Science 278, 866. PA0 Verma, I. M., et al. (1995). Genes Dev. 9, 2723-2735.


A method for managing quality of service (QoS) consists of receiving a packet and identifying at least one application level characteristic of the packet. The method for managing QoS further consists of modifying quality of service parameters of the packet based on the application level characteristic and sending the packet to a destination with modified quality of service parameters. A system for managing QoS includes modules such as a bearer module adapted to review and retrieve data from a packet and a payload packet inspector module adapted to identify at least one application level characteristic of the packet. The system for managing QoS further has a policy enforcement module designed to modify quality of service parameters of the packet based in part on the retrieved data and the at least one application level characteristic.

Long Term Evolution (LTE) networks are a standard type of network for wireless communication of high-speed data. LTE networks are based upon previous network technologies and are now used by many wireless carriers in North America and around the world. LTE networks are intended to have end-to-end quality of service (QoS) metrics.
In LTE networks, the quality of service data is provided on Evolved Packet Core Services (EPS) bearers. An EPS bearer is a virtual connection between a user's network equipment and a Packet Data Network Gateway (PGW).
An EPS bearer is characterized by:                A set of QoS parameters, often referred to as a QoS Class Index (QCI), which describe the type of service using EPS bearer. Types of service include, for example, conversational voice, streaming video, signaling, best effort, etc. Inside each EPS node, for example, the Packet Data Network Gateway (PGW), the Serving Gateway (SGW), eNodeB, and the like, the QCI points to more detailed pre-configured QoS attributes, for example, maximum delay, residual error rate, etc. These QoS attributes characterize the type of transport service provided by the EBS bearer;        A flow specification that describes the maximum bitrate (MBR) and/or guaranteed bitrate (GBR) of the aggregate traffic flow through the EBS bearer; and        A filter specification that describes the traffic flows, in terms of Internet Protocol (IP) addresses, protocols, port numbers, etc., for which the transport service is provided between the two endpoints.
However, conventional traffic differentiation in LTE networks is basic and based on classification criteria of Internet Protocol (IP) 5 tuples (5 main fields that are used to differentiate IP packets). This conventional traffic differentiation does not necessarily match today's applications. Generic classification techniques based on Destination IP address, Source IP address, Source or Destination Ports, or IP protocol, etc. are limited in their ability to differentiate traffic as the inspection of the packets is limited to the IP and Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) headers only. The conventional approach is too limited because many protocols (and therefore types of service) of interest to LTE network operators utilize arbitrary ports, may automatically change port numbers and may shift between TCP and UDP protocol.
It is, therefore, desirable to provide improved systems and methods for managing network traffic and quality of service of network traffic.

Systems and methods for managing quality of service


The vehicle power-generation control unit includes a voltage detecting circuit detecting a generation voltage of a vehicle generator driven by a vehicle engine, a switching device allowing an exciting current to flow into an exciting winding of the vehicle generator when the switching device is in an on state, an average duty ratio detecting circuit detecting a temporal average duty ratio of the switching device on the basis of the generation voltage, an enhanced duty-cycle signal generating circuit generating an enhanced duty-cycle signal having a duty ratio equal to the temporal average duty ratio added with a supplementary duty ratio determined depending on at least one of vehicle state information and vehicle generator state information, and a driver circuit driving the switching device with the duty ratio of the enhanced duty-cycle signal when the generation voltage detected by the voltage detecting circuit is lower than a predetermined target voltage.

1. Field of the Invention
The present invention relates to a vehicle power-generation control unit capable of performing gradual excitation for a vehicle generator.
2. Description of Related Art
As disclosed, for example, in Japanese Patent Application Laid-open No. 3-60338, there is known a vehicle power-generation control unit configured to gradually increase the exciting current of a vehicle generator when the output voltage of the vehicle generator drops as a result of application of an electrical load. With this vehicle power-generation control unit, it is possible to avoid abrupt lowering of a rotational speed of a vehicle engine, because, even when the output voltage of the vehicle generator drops abruptly as a result of application of an electrical load, the duty ratio of the exciting current flowing through the exciting winding of the vehicle generator is increased only gradually in order to avoid abrupt increase of the power generation torque.
There is also known a vehicle power-generation control unit configured to perform such a gradual-excitation control only for continuous electrical loads, and not for intermittent electrical loads such as a turn signal lamp and a hazard flasher as disclosed, for example, in Japanese Patent Application Laid-open No. 5-260679. This vehicle power-generation control unit makes it possible to avoid fluctuation of the output voltage of the vehicle generator, which can occur if the gradual excitation control is performed for the intermittent electrical loads, to thereby avoid the occurrence of brightness fluctuation of the turn signal lamp or hazard flasher. Determination whether an electrical load applied is a continuous load or an intermittent load can be made, for example, on the basis of the output voltage of the vehicle generator. In addition, this vehicle power-generation control unit has a capability of changing a gradual excitation time (the time span during which the duty ratio of the exciting current is gradually increased).
Since the increasing rate of the output power of the vehicle generator when the exciting current is increased gradually depends on the temperature and the rotational speed of the vehicle generator, it is also known to adjust the increasing rate of the duty ratio of the exciting current in accordance with the rotational speed and the temperature of the vehicle generator, as disclosed, for example, in Japanese Patent Application Laid-open No. 2002-204600.
However, the vehicle power-generation control unit disclosed in Japanese Patent Application Laid-open No. 3-60338, in which the increasing rate of the exciting current is constant, has a problem in that a terminal voltage of a vehicle battery (may be referred to as a battery voltage hereinafter) can be lowered excessively, and the engine speed can become unstable depending on the magnitude of an electrical load applied.
Also, the vehicle power-generation control units disclosed in Japanese Patent Applications Laid-open No. 3-60338, No. 5-260679, and No. 2002-204600 have a common problem in that the engine speed can become unstable and the battery voltage can be lowered excessively depending on a vehicle state (an engine torque state, for example) when a large electrical load having an inrush current such as an electric motor is applied.


A buck converter in accordance with the present invention provides multiple, well regulated, low voltage outputs. A cascaded buck converter comprises a main buck converter that is coupled to a subordinate buck converter through a cascade transistor in series with the free wheeling diode or transistor. The main buck converter is coupled to the free wheeling diode through the cascade transistor. Additional voltage outputs are possible by placing additional subordinate buck converters in series with the cascade transistor.. An isolated forward converter with multiple output voltages in accordance with the present invention may be derived using the cascaded buck converter topology. The cascading configuration permits multiple voltage outputs using a minimum number of switching devices while avoiding undesirable cross regulation.

Many modern electronic systems require more than one operating voltage. New generation integrated circuits, for example, call for multiple power supply voltages that are under 5 volts direct current (DC). Devices such as logic gates or microprocessors commonly require voltage sources of 5 V/3V3, 3V3/2V9, or 3V3/1V5. Thus, there is a demand for power conversion products capable of providing multiple, well regulated, low output voltages in a low cost package.
An example of a forward converter that produces multiple output voltages may be seen in FIG. 1. FIG. 1 is a circuit diagram of an isolated forward converter 2 with dual output voltages V.sub.out(1) and V.sub.out(2). Converter 2 includes a conventional isolated forward converter, which produces V.sub.out(1) across load resistor 20, and an additional voltage output source, which produces V.sub.out(2) across load resistor 36. The conventional isolated forward converter of converter 2 includes a transformer 4, a transistor 6 and capacitor 8, a diode 10, a free wheeling diode 12, an inductor 14, a capacitor 16, and a control circuit (not shown). Control of a conventional isolated forward converter is well known in the art. An explanation of the operation of the conventional isolated forward converter of converter 2 is therefore omitted for brevity.
To generate output voltage V.sub.out(2), converter 2 has a second inductor 24 and second capacitor 26 connected to transformer 4 via a magnetic amplifier 28, and a diode 30. A second free wheeling diode 32 is also connected between second inductor 24 and ground potential. Thus, inductor 24 is connected to ground potential via a separate free wheeling path than used by inductor 14. A magnetic amplifier control circuit 34 causes magnetic amplifier 28 to block and unblock the flow of current from transformer 4 into second inductor 24.
Converter 2 suffers power losses because of the wire gauge and number of turns in magnetic amplifier 28. Because magnetic amplifier 28 is driven into saturation each cycle, magnetic core losses can be high. These losses are worsened at high switching frequencies used to achieve high packaging densities in DC to DC converters. Additionally, converter 2 can be expensive due to the cost of magnetic amplifier 28 and the number of switching devices required for operation of converter 2, i.e., diodes 10, 12, 30, and 32.
FIG. 2 is a circuit diagram of another isolated forward converter 50 having dual output voltages. Converter 50 is similar to converter 2, like-numbered elements being the same. However, in converter 50 inductor 24 is connected, via a transistor 52, to a node between diode 10 and inductor 14. Converter 50 uses an electronic magnetic amplifier 51, which includes transistor 52 controlled by a control circuit 54. For example, control circuit 54 may be model number CS5101 manufactured by Cherry Semiconductor, Inc. As with converter 2, converter 50 has separate free wheeling paths for inductors 14 and 24, i.e., via free wheeling diodes 12 and 32, respectively. However, unlike converter 2, in converter 50 current flows from transformer 4 to both inductor 14 and inductor 24 via diode 10.
Circuit 50 requires a complicated bias voltage and gate drive voltage implementation for transistor 52. Further, there are potential cross regulation problems because transistor 52 is off when diode 10 is back biased. During the free wheeling period, there is no communication between inductor 14 and inductor 24. Thus, where V.sub.out(2) is loaded and V.sub.out(1) is not, converter 50 will be underpowered due to the lack of a path for current to flow between V.sub.out(1) to V.sub.out(2). Consequently, a load must be maintained on V.sub.out(1). Converter 50 is also expensive because of the number of switching devices, i.e., diodes 10, 12, 32, and transistor 52, and because of the expense associated with electronic magnetic amplifier 54.

Multiple output voltages from a cascaded buck converter topology


A partial seal platform for mounting a seal and securing seal to a rotor or a casing including a first arcuate securing segment with a first securing notch for receiving a first securing ridge of rotor or casing; a second arcuate securing segment with a second securing notch for receiving a second securing ridge of rotor or casing; an arcuate coupling segment with a first flat ridge forming a first and second lateral notch on each side of the first flat ridge for receiving the first arcuate securing segment and the second arcuate securing segment; and an arcuate mounting segment including a second flat ridge forming a lateral notch on each side of second flat ridge for receiving first arcuate securing segment and second arcuate securing segment.

In a steam or gas turbine, seals may be attached to a rotor or a casing. A seal on the rotor provides a seal between the rotor and the nozzles. A seal on the casing provides a seal between the casing and the buckets. A variety of seals, for example, seal teeth or seal brushes, are well known in the art. The relative ease or difficulty in assembling a turbine, disassembling a turbine, and packing (the overall configuration of parts) a turbine are all considerations in turbine and turbine component design.


A method of assembling a sand screen assembly includes the steps of providing inner and outer shrouds having radial protrusions, such as ribs, louvers, splines, etc., that are radially unaligned during a first assembly step thereby providing clearance for positioning of a filter layer between the shrouds. The outer or inner shroud is then rotated until the protrusions are aligned and the clearance between the shrouds and filter layer is eliminated to provide a tight fit between the layers.

Well screens are typically used to exclude sand and formation fines from fluids produced from subterranean wells. One or more sand control screen assemblies are commonly included in the completion string to control the movement of formation particles. Sand control screen assemblies are commonly constructed by installing one or more screen jackets on a perforated base pipe or liner. The screen jackets may include one or more drainage layers, one or more screen or filter layers, such as wire wrapped screen or single or multilayer wire mesh screen, and a perforated outer shroud.
Filter layers are known in the art and can be of various construction. For example, in "wire-wrapped" screen structures, the filter is formed by wrapping wire around the base pipe, with rods providing a standoff between the wire and the base pipe. Mesh screens consist of a woven single- or multi-layer mesh, typically of steel or other metal, shaped and combined with a protective, perforated outer covering in a cartridge, or jacket, which is slipped over a perforated base pipe. Filter layers can be formed of sintered or unsintered metal, bonded or non-bonded metal, wire mesh, multilayer wire mesh, woven wire, woven mesh, diffusion-bonded mesh, etc., as are known in the art or become known in the art. Multiple filter layers or laminates can be used in conjunction. As used herein, the term "filter layer" and similar includes multi-layer filters unless indicated otherwise.
Typically, a layer placed behind (radially inward from) the filter layer is provided to reduce resistance to fluid flow through the filter layer and is referred to as a "drainage layer." In some screen assemblies, the drainage layer is provided by placing a coarse mesh grid behind (radially inward of) the fine mesh filter layer. The drainage layer may also be made of a perforated stainless steel tube or liner, and can be referred to as an inner shroud since it is similar in construction to an outer shroud. A drainage layer can also be formed by creating a stand-off between the filter layer and inner shroud, such as by providing longitudinally and/or radially extending ribs, splines, etc., to maintain spacing between the layers.
An outer layer is typically referred to as a shroud or sleeve and can be formed of a metal tubular member having perforations extending radially through the tubular wall. The outer shroud is primarily for protection of the filter layer during insertion into the wellbore, handling, transport, etc., and can provide structural support as well. In some screen assemblies it is known to provide a stand-off between the outer shroud and the filter layer such as by providing ribs, splines, dimples, etc., on the interior surface of the outer shroud or outer surface of the filter layer.
It is known in the art to form the outer shroud separately from the filter body and slide it over an end of the inner tubular member until it surrounds the filter layer. After the shroud is disposed around the filter layer, the shroud is plastically deformed radially inwardly to reduce the inner diameter of the shroud to a value such that the filter layer can expand against the shroud. This process is also known as "swaging," and is typically achieved using a reducing mill or die. Swaging is undesirable because it adds to the time and expense of manufacturing the filter, deforms the outer shroud putting additional stresses on the shroud and affecting its material makeup, and does not guarantee that the clearance between the filter body and the shroud has been properly eliminated.
Where wire mesh is used as a filter layer in a well screen, it has been found that bonding operations (such as welding and brazing) performed on the wire mesh are detrimental to the long-term usefulness of the wire mesh. For example, the wire mesh may be thus made more susceptible to corrosion. An attempt has been made to address the problems associated with a bonded wire mesh filter layer by swaging an entire screen jacket, including the filter layer, onto a base pipe. An overlap in a wrap of the wire mesh filter layer is used instead of welding to seal the filter layer against sand migration. However, this method of swaging the screen jacket also imparts undesirable stress concentrations in the filter layer.
Assembly methods have been developed for assembling the various layers of a screen jacket or assembly. The layers can be formed by wrapping or spiral wrapping successive layers. For example, a metal wire is wrapped about an inner shroud to form a drainage layer, a filter layer is wrapped over the drainage layer, and an outer shroud is wrapped over the assembly. Wrapping techniques typically require welding, brazing, or other method, of creating a seam where the wrapped material meets, such as at the longitudinal ends of the filter layer, to form a cylinder. Obviously, such welding or other method can damage the filter layer and compromise the effectiveness and life of the screen assembly. Further, the filter layer longitudinal edges can be overlapped and secured by welding, brazing or other method involving heating of metal, crimping or other plastic deformation, or by friction with the inner and outer shrouds.
Alternately, the layers of the screen assembly can be positioned by moving (typically, lowering) one tubular layer over or into another tubular layer. For example, the outer shroud can be lowered onto a prepared inner shroud and filter layer. Such an operation requires a clearance or "play" between the layers.
It is desirable to have a tight-fit and radially thin screen assembly. Consequently, it is typical in the art to perform a secondary manufacturing process on the assembled screen assembly. Secondary processes include radial expansion, radial reduction, swaging, etc., to reduce or eliminate layer clearances, provide a press-fit or tight-fit assembly, "sandwich" the filter layer between shroud layers, etc. For example, the outer shroud can be radially reduced into secure contact with the filter layer. Alternately, the inner shroud and filter layer can be radially expanded within the outer shroud.
Further disclosure regarding screen assemblies and their manufacture can be found in the following references, each of which are hereby incorporated herein for all purposes: U.S. Pat. No. 7,287,684, to Blackburne, Jr., issued Oct. 30, 2007; U.S. Pat. App. Pub. No. 2007/0114171, to Chen, published May 24, 2007; U.S. Pat. No. 7,578,344, to Hopkins, issued Aug. 25, 2009; U.S. Pat. No. 8,176,634, to Bonner, issued May 15, 2012.
Therefore, it will be appreciated that improvements would be desirable in the art of constructing well screens. These improvements may find use in well screens which either do or do not have wire mesh filter layers.


The object of the present invention is to provide a temperature detecting method wherein a temperature detecting diode is formed in the proximity of and thermally coupled to an object of temperature detection element in the form of a semiconductor element so that, even when a high power is instantaneously applied, the temperature of the object element for temperature detection can be detected with a high degree of accuracy. According to the present invention, in a temperature detecting method for detecting, in a semiconductor device which includes an object element for temperature detection in the form of a semiconductor element and a temperature detecting diode formed in the proximity of the object element for temperature detection, the temperature of the object of temperature detection element from the ambient temperature and heat generated by the element, the temperature detecting diode is formed on the same pellet as that of the element at a position at which more than one half of the circumference thereof is surrounded by the object element for temperature detection.

1. Field of the Invention
This invention relates to a temperature detecting method which makes use of a forward voltage of a diode, and more particularly to a temperature detecting method wherein an object of temperature detection element in the form of a semiconductor element and a temperature detecting diode formed in the proximity of the object of temperature detection element are thermally coupled to detect the temperature of the element by means of the temperature detecting diode.
2. Description of the Related Art
Conventional temperature detection which makes use of a diode is described with reference to FIGS. 1 to 6.
As a conventional example including a temperature detecting method, a block diagram of a semiconductor device of three terminal construction having a built-in overheat preventing function is shown in FIG. 1. Object of temperature detection element 102 is formed from a bipolar transistor, a field effect transistor or a like element and serves as a heat generating source. Heat 106 generated from object of temperature detection element 102 is transmitted to temperature detecting diode D1. Temperature detecting diode D1 placed at position p converts a temperature into a voltage in accordance with the relationship between temperature T(p) and forward voltage VF(p) of the diode illustrated in FIG. 2.
Overheat protecting circuit 103 obtains voltage VF(p) representative of the temperature of object of temperature detection element 102 from temperature detecting diode D1 and operates switch SW1 to switch on or off in response to the value of voltage VF(p) to control the supplying condition of the input voltage to object of temperature detection element 102 thereby to control the temperature of object element 102.
A construction of a pellet for realizing the block diagram of FIG. 1 is shown in FIGS. 3(a) and 3(b).
Object element 102 for temperature detection such as a bipolar transistor or a field effect transistor and temperature detecting diode D1 are formed in a neighboring relationship to each other on silicon substrate 101 by diffusion processing. Overheat protecting circuit 103 is formed at a location on silicon substrate 101 comparatively far from object of temperature detection element 102. Those elements are connected by aluminum wiring lines or the like so that they cooperatively form a semiconductor device having an overheat preventing function.
An example of temperature detecting method wherein object of temperature detection element 102 and temperature detecting diode D1 are formed in a neighboring relationship to each other on the same chip and thermally coupled to each other to detect the temperature of object element 102 for temperature detection by means of temperature detecting diode D1 in this manner is disclosed, for example, in Japanese Patent Laid-Open Application No. Heisei 01-196858. This document discloses that a temperature detecting circuit which makes use of a forward voltage of a diode is incorporated on a pellet on which a driving transistor is mounted, and the driving transistor and the temperature detecting diode are individually connected to a device. This example is described below.
FIG. 4 is a schematic view showing a structure of the essential part of object element 202 for temperature detection and temperature detecting diode D1 disclosed in the document. The example shown in FIG. 4 employs an N-channel field effect transistor of the enhancement type. In FIG. 4, a portion formed by terminals G, D and S is a field effect transistor serving as object element 202 for temperature detection, and another portion formed from terminals A and K serves as temperature detecting diode D1.
As described above, conventional temperature detecting diode D1 is formed such that it is included in a block adjacent object element 202 for temperature detection such as the block of overheat protecting circuit 203.
A concrete temperature detecting circuit employing temperature detecting diode D1 is shown in FIG. 5. Temperature detecting diode D1 is connected in a forward direction, and detecting current of several mA flows through temperature detecting diode D1. Voltage VF(p) across temperature detecting diode D1 is compared with reference voltage Vref set by resistors R7 and R8 by comparator Cmp1, and voltage Vo is outputted from comparator Cmp1. An example of temperature detecting circuit of the type described above is disclosed in Japanese Patent Laid-Open Application No. Showa 56-120153 or Japanese Patent Laid-Open Application No. Heisei 1-114060.
The temperature detecting circuit disclosed in Japanese Patent Laid-Open Application No. Heisei 56-120153 is constructed such that a diode for detecting the temperature is disposed adjacent another pellet or the same pellet in the proximity of an object element for temperature detection such as a transistor or an IC, and a temperature detecting circuit which makes use of the forward voltage of the diode is incorporated in the outside or the inside of the IC and the forward voltage of the diode including the temperature information is compared with a reference voltage by a comparator or an operational amplifier to control the current flowing through the IC to protect the device. Also overheat protecting circuit 103 shown in FIG. 1 has a similar construction to that disclosed in Japanese Patent Laid-Open Application No. Showa 56-120153.
The temperature detecting circuit disclosed in Japanese Patent Laid-Open Application No. Heisei 1-114060 is constructed such that a temperature detecting circuit including a transistor for detecting the temperature is disposed in the proximity of an object element for temperature detection and makes use of a forward voltage of the diode between the base and the emitter of a transistor forming an IC to control the current of a power source connected to the IC to protect the device.
The temperature distribution on the section taken along line Z-Z' of the schematic views of FIGS. 3(a) and 3(b) including temperature detecting diode D1 immediately after a high power is instantaneously applied to the semiconductor device shown in FIGS. 3(a) and 3(b) is such as that shown in FIG. 6.
The temperature distribution on the section taken along line Z-Z' usually exhibits the highest temperature (Tmax) at the location of object element 102 for temperature detection, and the temperature of temperature detecting diode D1 spaced by distance p from object of temperature detection element 102 is T(p) which is lower than temperature Tmax of element 102.
Where the applied power is represented by P, the maximum temperature of element 102 is represented by Tmax and the thermal resistance between temperature detecting diode D1 at position p and element 102 is represented by Rth(p), temperature T(p) at position p of temperature detecting diode D1 in the conventional example is given by following equation 1: EQU T(p)=Tmax-P.times.Rth(p) equation 1
Further, when sufficient time elapses after power is applied to the semiconductor device, the temperatures of both element 102 and temperature detecting diode D1 approach a substantially uniform temperature.
However, in the prior art described above, as seen from FIGS. 3(a) and 3(b), a thermal resistance originating from the thermal conductivity and/or the distance between object of temperature detection element 102, which also serves as a heat generating source, and temperature detecting diode D1, and particularly when a high power is instantaneously applied or in a like case, a difference arises between temperature Tmax of element 102 and temperature T(p) of temperature detecting diode D1 as seen in FIG. 6. Consequently, where the prior art is applied to an overheat protecting circuit or a like circuit, there is a problem in that the temperature of element 102 may become higher than an overheat protecting temperature set in advance by resistance R7 and resistance R8 of the temperature detecting circuit of FIG. 5.
This problem is not significant while the input power to the semiconductor is low. However, when a high power is inputted instantaneously, the problem becomes significant. Accordingly, not only realization of a semiconductor device having an overheat protecting function or a like function is difficult, but also there is the possibility that the life of the semiconductor device may be reduced by inadvertent application of a high power.

Semiconductor device with temperature detecting diode, method of forming the device and temperature detecting method using the device


A gridded spacer assembly (130, 230) for a field emission display (100, 200) includes a plurality of spacers (135, 235), a focusing grid (132, 232) having a plurality of spacer apertures (133) in which the spacers (135, 235) are disposed and to which the spacers (135, 235) are affixed adjacent their lower end, a stabilization grid (138, 238) having a plurality of spacer apertures (137) in registration with the spacer apertures (133) of the focusing grid (132, 232), the spacers (135, 235) being disposed therein and affixed thereto adjacent their upper end, the focusing grid (132, 232) and the stabilization grid (138, 238) having a plurality of focusing apertures (139) for collimating and focusing a beam of electrons (150).

Field emission displays are known in the art. They include an envelope structure having an evacuated interspace region between two display plates. Electrons travel across the interspace region from a cathode plate (also known as a cathode), which includes electron-emitting devices, to an anode plate (also known as an anode), which includes deposits of a light-emitting material, or "phosphors". Typically, the pressure within the evacuated interspace region between the cathode and anode plates is on the order of 10.sup.-6 Torr.
Spacers for field emission displays are also known in the art. The cathode plate and anode plate are thin in order to provide low display weight and reduce package thickness. If the display area is small, such as in a 2.54 cm diagonal display, and a typical sheet of glass having a thickness of about 0.1 cm is utilized for the plates, the display will not collapse or bow significantly. However, as the display area increases the thin plates are not sufficient to withstand the pressure differential in order to prevent collapse or bowing upon evacuation of the interspace region. For example, a screen having a 76.2 cm diagonal will have several tons of atmospheric force exerted upon it. As a result of this tremendous pressure, spacers play an essential role in large area, light-weight displays. Spacers are structures being incorporated between the anode and the cathode plate. The spacers, in conjunction with the thin, lightweight, plates, support the atmospheric pressure, allowing the display area to be increased with little or no increase in plate thickness.
Several schemes have been proposed to provide display spacers. These spacers and methods have several drawbacks. Methods for fabricating spacers which employ screen printing, stencil printing, or the use of glass balls suffer from the inability to provide a spacer having a sufficiently high aspect ratio (the ratio of spacer height to spacer thickness). Prior art methods which include aligning each individual spacer require repeated alignment steps and the adhesion of each spacer so that they will remain upright during subsequent packaging and sealing steps. These requirements are time consuming and add complexity.
Spacers for a field emission flat panel display must be invisible to the viewer. That is, they must be narrow enough to fit between the pixels of the display. Typically, the anode is coated with phosphor dots which are surrounded by a "black surround" material. This black surround material serves to increase the contrast ratio of the display and prevent the scattering of light between pixels. If the spacers are narrow enough to fit in the black surround area, then they will be invisible to the viewer. As an example, a 26.4 cm VGA display is easily designed to allow about 150 micrometers wide black surround stripes in one axis. Allowing for various tolerances, this means that spacers which are less than 100 micrometers wide would easily fit in the available space. It may be shown, for example, that glass rods having a diameters of 75 micrometers placed in a square pattern having a pitch of about 0.5 cm would satisfy both the invisibility and the structural strength requirements. The height of the spacer and, consequently, the aspect ratio is determined by the operating voltage. For a display designed to operate at 5,000 volts, a distance of about 1 millimeter is required between the anode and cathode plates of the display in order to prevent arc break down. The resulting aspect ratio is therefore about 10:1, which tends to make the spacers difficult to position and place accurately.
Accordingly, there exists a need for an apparatus and method for incorporating spacers into a field emission display which provides high aspect ratio spacers and ease of spacer placement and alignment.

Gridded spacer assembly for a field emission display


The invention provides a device containing an ion-exchange resin to which is chemically bound a fuel additive material which will gradually be released from the resin into a fuel in which the device is placed.

Additives for fuels have long been known and used to improve combustion, reduce emissions, minimise or clean up combustion chamber deposits and in-take valve deposits. Such fuel additives have traditionally been blended with the fuel at the refinery, or added later in the pipeline or in transit between the refinery and the final consumer.
It is difficult to maintain a constant or desired level of an additive in the fuel. Typically an operator adds a bottled additive to the vehicle fuel tank with each fuel fill-up. While many bottled fuel additives are commercially available, often operators do not consistently add the additive with each fill-up. The additive might not be readily available or the operator may forget to include the additive. When the additive is added to the fuel tank, it does not always form a homogeneous mixture with the fuel. Fuel tanks do not include reliable methods for mixing fuel. Generally operators rely upon the turbulence created during a fill-up and by vehicle motion to mix the additive and fuel. Furthermore, the additive concentration in the fuel may vary, depending upon the amount of fuel added—assuming a set amount of additive is added with each fill-up.
Ion exchange resins have been used in various chemical systems for the exchange or release of certain chemically bound materials.
U.S. Pat. No. 6,238,554 teaches a fuel filter for use with internal combustion engines. The fuel filter includes a fuel additive that can be released into fuel.
Therefore, a need exists for a device and method to provide a fuel additive to a fuel supply in a time-release manner.

In-tank time release ion exchange resin containing a fuel additive


A vehicle door lock apparatus utilizes Hall-effect sensors for the position of an element in a latch or locking system and, according to the invention, the Hall-effect sensor chip or the evaluating circuitry enables the generation of first control signals when the first information signal current amplitude is above an upper threshold, the generation of second control signals with a second information signal below the upper threshold is above a lower threshold and an alarm signal when the information signal is between the lower threshold and zero. In this manner defects in the Hall-effect sensor, the conductive path between the Hall-effect sensor and the evaluating circuitry and in the current supply to the Hall-effect sensor can be detected simply and economically.

Hall-effect sensor chips can generate different information signals which are transformed by the electronic circuitry connected thereto to different control signals. The control signals, in turn, can, in a vehicle door lock system, bring about the different functions of the latch or bolt system and the locking system, usually via motors or other drivers or effectors which displace the elements, for example, levers of the door locks and/or energize control lamps or other signalling devices.
For example, one effector or motor can operate the bolt mechanism of a door lock for latching and unlatching that door lock, of a central locking system for the vehicle as a whole. In this arrangement and in the preferred embodiment of the invention, two Hall-sensor chips can co-act as part of the control system to signal the position or status of the lock or lock element.
When reference is made here to a latching or bolt system, we mean to describe the type of central locking system for a vehicle in which an effector can rotate the bolt of the lock into and out of engagement with the pin on the door post and can operate the usual keeper for the rotary bolt. When we refer to the lock system for this arrangement, we mean to include at least one mechanical lock cylinder which can be rotated by a mechanical key and which normally has three functional positions, namely, an intermediate starting position, a latching and unlatching position to one side of the intermediate position and in which the bolt can be operated in the manner described, and an antitheft position to the opposite side of the intermediate position and in which, upon rotation of the cylinder into this position, the door locks can be secured in an antitheft arrangement. In this position, operation of the door locks is blocked.
The locking cylinder can cooperate with the control circuitry of the vehicle door lock system which can also receive inputs or can interrogate the door locks as to current status of the positions of elements thereof or can interrogate the cylinder as to its position. To this end, the position detectors can be Hall-effect sensor chips in the manner described or the Hall-effect sensor chips can be positioned to detect the selected positions of the lock cylinder.
For example, the lock cylinders can have two fixed Hall-effect sensor chips each with a respective Hall-effect sensor and chip circuit, and a ferromagnetic element which is operatively connected or forms part of the lock cylinder and which can detect the position of the lock cylinder. The lock cylinder can have an intermediate zero position. Generally speaking the Hall-effect sensor chips or the circuitry therefor can have a lower current threshold and an upper current threshold.
Door locks of this type are described, for example, in DE 196 34 321, corresponding to U.S. application Ser. No. 08/915,897 filed 21 Aug. 1997 by Hagen FRIEDRICH, Andreas SIEKIERKA and Thorsten TORKOWSKI, and DE 296 18 688 U1, corresponding to U.S. application Ser. No. 08/950,792 filed 16 Oct. 1997 by Peter BARTEL, Johannes-Theodor MENKE and Thorsten TORKOWSKI. Reference may also be made to EP 0 694 665 A1.
The described door locks utilize Hall-effect sensor chips which can generate first information signals of a high current level I.sub.high and second information signals at a lower current amplitude I.sub.low. However, defects in Hall-effect sensor chips, in the conductive path or circuitry between a Hall-effect sensor chip and the evaluating circuitry, or in the current supply of a Hall-effect sensor chip can arise and can interfere with the operation of such systems.

Vehicle door lock with a latch system and a locking system and electronic control


To provide a pattern correction apparatus which enables easy correction of a trace which is not present on trace grids, a pattern correction apparatus which makes a correction to a pattern of an integrated circuit includes a trace movement section for moving, among traces forming the pattern of the integrated circuit, a trace which is not present on trace grids to a position above the trace grids; a pattern correction section for making a correction to the pattern; and a trace pitch optimization section for optimizing a trace pitch between traces forming a pattern corrected by the pattern correction section.

1. Field of the Invention
The present invention relates to a pattern correction apparatus, a pattern optimization apparatus, and an integrated circuit design apparatus for correcting, optimizing, and designing a pattern of an integrated circuit.
2. Description of the Related Art
With a leap progress in LSI manufacturing techniques, an ultrafine process called deep submicron has been used. From a physical viewpoint, further miniaturization a process poses difficulty in designing a layout. Moreover, in relation to a signal delay (a gate delay or a trace delay), the influence of a trace delay becomes greater, and hence a contrivance to trace design is required.
In association with the shorter life of LSI products, yields of the LSI manufacturing technique must be enhanced immediately. For instance; in order to realize a design for simpler production, a commitment to a DFM (Design For Manufacturing) technique is sought. Improvements in design quality and reductions in fraction defective are sought not only in the field of LSIs for use in automobiles but also in the field of consumer-oriented or industrial LSIs.
What greatly affects a trace delay as a result of a reduction in the minimum pitch between wires associated with recent miniaturization is crosstalk. A principle approach for avoiding occurrence of crosstalk is a reduction in inter-trace capacitance and asynchronous switching among adjacent wires. A method for increasing a trace pitch is available for reducing inter-trace capacitance. For example, in connection with layout data acquired after detailed routing, a trace pitch disregarding trace grids is enlarged by use of an automatic layout tool.
Next, a finer design rule poses extreme difficulty in mask processing, which in turn raises a problem of deteriorated yields and a failure to manufacture an LSI at worst. These problems are attributable to a graphics pattern of a semiconductor mask being finer than the wavelength of light used for exposure. Further, at some locations, the problems are attributable to a layout relationship between wires and vias. For example, when denseness and nondenseness are present in the pattern, it may be the case where a pattern cannot be transferred accurately.
Although degeneration failure or open failure is detected by use of a test pattern, detecting all nodes is difficult to perform. There is the possibility of a short circuit or a break arising between traces as a result of minute dust or extraneous matters having adhering to nodes (undetected nodes) that cannot be detected by means of the test pattern, to thus cause product deficiency.
An example of the technique for creating a layout pattern which is intended for reducing the chance of occurrence of a cross talk in an LSI or enhancing yields is described in JP-A-2005-301799. Correction of a layout of a pattern of an integrated circuit will be described briefly by reference to FIG. 28.
As shown in FIG. 28, a method for correcting a pattern of an integrated circuit comprises selecting an arbitrary trace pattern by means of taking, as an input, pattern information (21-1) which is an aggregate of trace patterns (step 21-2); computing the degree of adjacent balance from inter-trace capacitance between a trace pattern R selected in step 21-2 and a trace pattern adjacent to the trace pattern R (step 21-3); and moving the position of an adjacent trace pattern in accordance with the degree of adjacent balance computed in step 21-3 (step 21-4).
According to the above method, an adjacent trace pattern is moved in accordance with the degree of adjacent balance determined from inter-trace capacitance developing between a selected trace pattern and an adjacent trace pattern, so that a trace pitch can be increased when compared with a trace pitch determined by the original trace pattern. Therefore, optimization of timing of an LSI chip and realization of a layout which diminishes crosstalk are possible, and yields can be enhanced.                Patent Document 1: JP-A-2005-301799
However, under the previously described method for correcting a pattern of an integrated circuit, when a necessity for correcting a trace pattern after optimization of a trace pitch has arisen, it is difficult to correct a trace which is not present on any trace grid by use of an automatic routing tool. Even if correction of the trace is feasible, enormous time is consumed. Further, an evaluation function does not include vias, it may be the case where yields are reduced by means of denseness and nondenseness of the graphics pattern. In association with further miniaturization of a process in future, denseness and nondenseness of a graphics pattern pertaining to vias must also be taken into consideration.
Moreover, a fraction defective in the market (hereinafter called a "market fraction defective") is computed from the rate of detection of degeneration failures acquired by use of a test pattern. However, in association with miniaturization of a process, a market fraction defective cannot be ascertained by means of a parameter including only the rate of detection of failures determined through use of a test pattern. Further, since graphic pattern information is not included in parameters used for computing a fraction defective, graphics pattern correction for diminishing a market fraction defective cannot be made.

Pattern correction apparatus, pattern optimization apparatus, and integrated circuit design apparatus


In a case where a sheet for sample printing is fed from a feeding deck after an instruction for executing the sample printing is received, a long period of time is required to discharge the sheet which has been subjected to the sample printing to a sample tray. Control is performed such that the sample printing is performed on a specific one of a plurality of sheets fed from sheet holding units for executing main printing, when an instruction for executing the sample printing is received from the user.

Printing apparatuses which perform printing of a page being printed on a sheet which is different from a sheet for main printing (hereinafter referred to as "sample printing") so that a user checks quality (layout and colors, for example) of a printed matter have been used. Such a printing apparatus discharges a sheet which has been subjected to the sample printing to a discharge tray (a sample tray) which is different from a discharge tray (a stack tray) for the main printing (refer to PTL1).

Printing apparatus, method for controlling the same, program, and storage medium


An improved coal mill exhauster fan having an elongated, conical hub welded to the blades and engaging the rear shroud plate to eliminate air gaps along the rear of the fan assembly and to assist in axial to radial directional changes of the coal flow; two-piece blade assemblies having a sub-blade welded directly to the hub and shroud plates, and a protective liner removably secured to the sub-blades only, for example by bolts; a plurality of swept-back stiffener ribs welded to the rear undersides of the sub-blades, hub and shroud to increase rigidity, and with angled deflector faces to reduce erosion; and an improved hub cap or spinner seal which extends further toward the housing inlet than traditional Cooley caps and which forms a smooth, non-turbulent extension of the hub relative to the incoming coal flow.

Coal-fired power plants typically burn pressurized coal/air streams delivered to a fireball in the combustion chamber. The coal/air stream is delivered by a powerful exhauster fan located in series between the combustion chamber and the coal mill or pulverizer, which grinds raw coal into dust-like "fines" for efficient combustion.
An example of a typical pulverizing coal mill is disclosed in U.S. Pat. No. 5,386,619 to Wark.
An example of a prior exhauster fan is disclosed in U.S. Pat. No. 5,363,776, also to Wark. This patent illustrates the pathway from the pulverizer through the fan to the combustion chamber.
Prior exhauster fans, as disclosed in the '776 patent above, typically enclose the fan blades in a housing. The housing has an inlet from the pulverizer directing coal axially into the spinning blades. The blades then redirect the coal radially in the housing, to and through an outlet to the combustion chamber. The blades themselves are heavy, usually rectangular plates of hardened steel or a combination of mild steel with a hardened liner, for example a ceramic liner. The blades are attached to a motorized hub with a strong, heavy "spider" assembly of heavy-gauge steel spokes having angle irons to which the plates are bolted with a dozen or so bolts apiece.
Referring first to prior art FIGS. 1 and 2, a prior art exhauster fan assembly 14 is shown mounted in its housing 10. Housing 10 has an inlet 12 for receiving coal fines which it draws from the pulverizer, and a radial outlet 30 through which the fan throws the coal fines to the combustion chamber. Fan 14 generally comprises a drive hub 16, typically powered via a cantilevered drive shaft 17 by a motor which is coupled simultaneously to the fan and the pulverizer drive. Fan blades 20 are attached to the hub by a spider assembly 18 having a number of integrally formed, spoke-like ribs 18a, dual angle irons 18b mounted on the end of each rib, and a number of bolts 18c used to fasten the plates directly to the angle irons 18b. The fan assembly is primarily made from thick steel, reinforced at areas of extra wear, and is extremely heavy. The fan blades 20 themselves, which may measure several feet in length, are typically manufactured from a 3/8" thick hardened steel blade, or a 1/4" to 5/16" mild steel blade with a 1/8" to 3/16" hardened ceramic liner.
To reduce turbulence and wear between the fan blades and the housing, illustrated fan 14 may be a "shrouded" fan, in which the blades are enclosed front and back with shrouds 22, 24 (phantom lines) welded or attached via angle iron and bolt structure (not shown) directly to the front and back edges of the blades to form a structurally integral unit. Shrouds 22, 24 are intended to reduce drag and turbulence between the fan blades and the adjacent walls of housing 10. Fan assembly 14 may also be provided with known "whizzer disk" and angle structure 23, 25 in addition to front shroud plate 22.
The front of hub 16 is provided with a conical or flat "Cooley" cap 28 intended to protect the hub and redirect incoming coal fines radially to the fan blades, although in practice it creates turbulence and does not effectively protect fan structure such as the ribs from erosion.
Coal mills often measure efficiency by the pounds per hour of coal fines delivered to the combustion chamber, given a fixed power input to the motor which drives both the exhauster fan and the pulverizer bowl mill. Because the output of the motor is limited, increasing efficiency requires attention to other factors, for example the ability of the fan to provide sufficient flow to keep up with the bowl mill pulverizing action and to prevent ground coal from spilling over the side of the bowl. Alternately, where the air flow provided by the existing fan design is more than sufficient, it may be desirable to reduce the horsepower supplied to the fan to increase the horsepower supplied to the bowl mill, for example where the mill's coal supply is switched from easy-to-grind soft coal to hard coal.
Related factors which affect efficiency or performance, besides the size of the fan blades, are 1) the overall weight of fan assembly 14, which requires more amperage on motor startup and draws more horsepower during operation; 2) erosion and uneven wear of the fan parts, which creates fan imbalances leading to excess vibration, bearing failure, and structural failure of the heavy fan on the end of its cantilevered drive shaft and 3) how easily the fan "breathes" in terms of smooth coal/air flow through the eye of the fan for a given horsepower.
In terms of weight, the standard spider assembly 18 with its angle irons, bolts and heavy ribs and blades is a major power draw on the motor. The angle iron and bolt attachments for the front and back shrouds are also a significant source of weight. Extra weight on the cantilevered fan shaft bearings (not shown) increases the rate of bearing failure. Also, the heavy spider assembly concentrates weight on the very end of the drive shaft and distributes it over a long moment arm radially outward from the drive shaft.
In terms of erosion, the ribs 18a of the spider assembly tend to wear significantly, especially toward the center of the fan where the Cooley cap initially diverts the abrasive coal flow into the center of the blades. The unshrouded rear inside edge 20a of the fan blades creates turbulence and drag, since air swirls turbulently in this "air gap". Ribs 18a additionally obstruct the coal flow as it enters the blade region, further reducing efficiency.
When any of the above-mentioned portions of the fan becomes significantly eroded, the fan must be taken off-line for repairs or replacements, at which point the integral structural connection of the shrouds and the fan blades, and the large number of bolts connecting each fan blade to the spider assembly, make disassembly difficult and time consuming.
Another disadvantage of the prior art spider assembly 18 is the difficulty in assembling and maintaining a symmetrical, balanced fan given the large number of angle irons and bolt-together pieces.