In a method for configuring the network address for a node in a IP wireless network a network address is selected out of an available range of network addresses. At least one address resolution request (ARP) is sent over the network. A response to the ARP requests is awaited during a pre-defined timeout. In case no response is received from the network, the selected address is used to configure the node of the network.

In managed networks, the host sends a request to a central DHCP server and configures its IP stack with the IP address received in the answer packet from the DHCP server. However, ad-hoc networks might not have access to backbone networks and no connectivity to a DHCP infrastructure. In this scenario the IP addresses can be configured manually by each user or autonomously by the host with a so-called ZeroConf mechanism e.g. described in the U.S. Pat. No. 6,061,739. U.S. Pat. No. 6,061,739 relates to an initial network address configuration using physical address resolution protocol. A device attends a connection to the network, which causes address resolution (ARP) packets to be generated. The device monitors communications on a network for a specified number of unanswered ARP packets. Thereafter, the device adopts the network address in the unanswered ARP packets.
Using ZeroConf each host selects randomly an IP address from a preset range and sends out a number of ARP requests for the selected address. After the ARP request has been sent, the host listens for a specified waiting time, the so-called "timeout period". If the host receives no ARP reply during said timeout period, it assumes the selected address being unused and configures its own IP stack with said selected address. The mechanism according to the prior art recommends selecting the timeout periods pending on the link layer technology in a range from 200 milliseconds to 2 seconds.
The known mechanism of ZeroConf configuration thus describes a mechanism to configure automatically a unique link local IP address for IP-v4 without support from external infrastructure like e.g. DHCP servers in small ad-hoc networks. The ZeroConf specification describes the optimal messages sequence for switched wired network with low risk of packet losses, but possible delay due to forwarding delay on intermediate nodes in the network backbone.
ZeroConf performs the following steps:                1) Select randomly one IP address from the defined range 169.254.1.0 to 169.254.254.255,        2) Wait for a random time between zero and two seconds,        3) Send out four ARP requests for the selective address spaced two seconds apart. If an ARP response is received at any time during the process the host assumes the address as being taken by another node and restarts the mechanism of step 1,        4) If no ARP response has been received, wait for additional two seconds for an answer and assume otherwise the address as being free as a new link local address.
U.S. Pat. No. 6,101,499 teaches how to select an IP address which can be used e.g. in the above step 1. According to U.S. Pat. No. 6,101,499 first a proposed IP address is generated by selecting a network-identifying portion (sometimes known as IP network prefix) while deterministically generating the host-identifying portion based on information available to the IP host. For example, the IEEE 802 Ethernet address found in the network interface card may be used to in a deterministic hashing function to generate the host-identifying portion of the IP address. Next, the generated IP address is tested on the network to assure that no existing IP host is using that particular IP address. If the generated IP address already exists, then a new IP address is generated, otherwise, the IP host will use the generated IP address to communicate over the network. While using the generated IP address, if an IP address server subsequently comes available, the host will confirm to IP address server protocols for receiving an assigned IP address and gradually cease using the automatically generated IP address.
U.S. Pat. No. 6,101,499 thus teaches to deterministically generate at least a portion of the selected address in contrast to the random selection as proposed in the original ZeroConf mechanism.
The ZeroConf mechanism has been developed for a switched wired network (e.g. Ethernet) with low risk of packet losses but a potential for substantial delays. To take account of the possible delays, long timeouts and delays (e.g. two seconds) have been set, such that the overall process for configuring a host with a unique link local IP address can take up to e.g. twelve seconds. The known ZeroConf mechanism therefore has been specified for wire-based networks.
It is the object of the present invention to adapt the configuration process developed for wire-based networks to the needs of networks having wireless links.
Thereby, it is particularly the object of the invention to improve the process taking into account the constraints of wireless links. For example, in wireless Bluetooth networks the risk of a packet loss is higher than in wired networks, while the possible delays are shorter.
The object is achieved by means of the features of the independent claims. The dependent claims develop further the central idea of the present invention.
According to a first aspect of the invention therefore a method for configuring a network address for a node in a wireless network is proposed. Note that "wireless network" is to be understood that the network does comprise at least one wireless link from the node to be configured to an adjacent node. Other links of the network, if there are any, can be wire-based. At first a network address is selected out of an available range of network addresses. Then at least one address resolution request is sent out over the network. Further on, a response from the network is awaited indicating that another user already uses the selected address. In case no response indicating that the selected address is already used by another node of same network is received within a pre-defined waiting time, the selected network address is used. According to the invention, thereby beforehand is decided which network topology out of plurality of pre-defined network topologies is used. Then the parameters of sending the resolution request and waiting for the response from the network are adapted according to decided network topology.
The pre-defined network topologies can be respectively associated with a pre-defined parameter set, wherein, according to the decided network topologies the corresponding parameter set is used.
The network topology can e.g. be decided based on messages received from the network (e.g. in a service discovery process). Alternatively, the network topology can be decided by the node to be configured (e.g. the user of the node can manually select a network topology he wants to use for the future communication).
The parameters to be adapted can be at least one of the delay/waiting times and the number of requests sent.
The steps of sending at least one address resolution request and waiting for response from the network can be repeated for a predetermined number of the petition times. Said repetition number can also be adapted according to the decided network topology.
According to a further aspect of the present invention, the predefined network topologies can include at least one of:                a network comprising two wireless nodes only,        a network comprising more than two wireless nodes, wherein the nodes are able to communicate by using forwarding functionality in a master node of a network, and        a network comprising a plurality of wireless nodes able to communicate with the backbone network via a network access point.
According to a further aspect of the present invention, a configuration method is characterized in that a plurality of address resolution request is sent out essentially without any delay between two successive requests.
The network address selected can be selected randomly or pseudo-randomly out of the available range of addresses.
The network can comprise Bluetooth links.
Finally, the present invention proposes a mobile terminal having a processor with a protocol stack and a network card adapted to carry out such a method.
In the following the invention will be explained with reference to the so-called "Bluetooth Personal Area Networks" using the IP protocol. However, it is to be noted that the present invention is not limited to IP networks, but can be adapted to any networking protocol and link layer technology adapted to support different network topologies.
The following explanation, however, describes the invention using IP based Bluetooth PANs as an example.
The present invention extends the known ZeroConf mechanism to adapt it not only to the underlying (physical) link layer technology, but also to the network topology in order e.g. to shorten the set-up time without introducing uncertainties about the result of the configuration process. Therefore according to the invention not only short-range information regarding the link the host is using is taken into account, but also information on the structure of the network.
The invention will now be described in more detail by reference to the Bluetooth radio system and Personal Area Network (PAN) profile as an example. However, the invention can be used in connection with other wireless technologies, as long as each node can make initial assumptions or decisions about the network topology used.
The Bluetooth PAN profiles specifies three different roles and describes combination of roles between which links can be established. Each combination maps to one the network topologies shown in FIG. 1.
Network Topology A: PANU-PANU Networks
A PANU-PANU network consists of only two nodes 1, 3 which are directly connected by means of a wireless link 2 and which have no additional Bluetooth PAN connections. Therefore, a host only has to check whether the other host has already chosen the same IP address from the available ZeroConf IP address range.
Network Topology B: Group Networks
A group network node (GN) 4 connects multiple PANUs 1, 3 to one network and forward packets between the connected PANUs 1, 3. Group networks consist of a group network node 4 and up to e.g. seven connected Bluetooth slaves. A newly connecting host therefore has no knowledge about the number of hosts in the group network and the traffic patterns in the network.
Network Topology C: Network Access Point Networks
This type of network consists of a group of Bluetooth devices 1, 3, which can communicate with hosts 5 in the Bluetooth domain and hosts 7 in the backbone network 6 via a Network Access Point (NAP) 5. These networks consists of a Network Access Point 5, up to seven connected Bluetooth slaves and hosts connected to the additional backbone network segment of the network access point. Newly connecting hosts can make no assumptions about the topology of the backbone network.
According to the present invention, e.g. the three above network topologies are defined and parameters for the ZeroConf process are predefined for each of the defined network topologies. A newly connecting host then can either decide itself which network topology with associated parameters set is to be used for the ZeroConf selection process or after detecting available topology information e.g. via the service discovery profile (SDP).
In order to minimize the configuration time for IP hosts in ad-hoc networks, the invention proposes to introduce multiple ZeroConf profiles to be used depending to the underlying link layer technology and network topology. A ZeroConf profile defines a set of parameters for specifying the ZeroConf process to be used for the associated network topology and link layer technology. The corresponding steps will now be explained with reference to FIG. 2.
In a first step S1 the role of the local and the remote device and the resulting network topology are determined. This step can for example be carried out by means of a device inquiry and a service discovery process.
In a second step S2 a ZeroConf profile is selected according to the decided topology and/or link layer technology.
In a step S3 the ZeroConf profile selected is transferred to an extended ZeroConf entity.
Finally in a step S4 the extended ZeroConf process according to the present invention is started.
FIG. 3 shows the extended ZeroConf mechanism according to the present invention in more details. As shown in FIG. 3 mechanism is designed to perform multiple cycles. In each cycle the host starts to listen for IP name resolution responses for the initially selected IP address and send out a plurality of ARP requests to this address without delay. After the ARP requests have been sent out, the host waits for defined timeout period before assuming the address as free or performing additional rounds of ARP proving.
Now the single steps of the mechanism of FIG. 3 will be explained in more detail.
In a step S4 an IP address is selected from the ZeroConf address range. The ZeroConf address range is thereby predefined. The selection can e.g. be carried out using a random or pseudo-random selection process. Alternatively, deterministic selection procedures e.g. as shown in U.S. Pat. No. 6,101,499 can be used.
In a step S5 the "round number" is set to zero.
In a step S6 the "number of ARP requests" for "ground number" is determined. Note that "number of ARP requests" is one of the parameters of the parameter set to be adapted according to the link layer technology and network topology decided.
In a step S7 the "ARP request counter" is set to zero.
In a step S8 the nodes starts to listen for ARP responses for the address selected in step S4.
In a step S9 an ARP request for the selected address is sent out to the network and "ARP request counter" is implemented.
In a step S10 it is decided whether all ARP requests are sent out for this cycle without delay.
In case all ARP requests are sent out, in a step S11 the node listens for ARP responses for the selected address for the timeout for the round "round number". Note that the valley of the timeout for the listening in step S11 is a further parameter specified in the parameter set of the ZeroConf profile which is adapted according to the selected link layer technology and decided network topology.
In case in a step S11 an ARP response is received from the network during the timeout period of step S11, the procedure goes back to step S4 and a new IP address from the ZeroConf address range is selected.
In case during the timeout period specified no ARP response for the selected address is received from the network, the parameter "round number" is implemented in step S13. Note that the maximum value of "round number" is a further parameter of the parameter set of ZeroConf profile adapted according to the underlying link layer technology and network topology.
In a step S14 it is decided whether all round of the profile are performed. If the decision is negative, the procedure goes back to step S6.
If the decision in step S14 is positive, and all rounds of the profile have been performed, the host is configured with the IP address selected in step S15.
The ZeroConf profile is determined depending on the network topology and the used link layer technology and specifies how many ARP packets should be sent without delay in each round. This number can depend on the radio technology and the probability of packet losses. Because Bluetooth enables hosts using the PAN profiles are normally configured to try to send a packet only a limited time before a dropping the packet, each ARP message is sent a multiple of times. This might not be necessary for reliable radio technologies.
For the three different PAN topologies shown in FIG. 2, the following number of rounds, timeout periods and number of ARP packets according to the following ZeroConf profile are proposed:
PANU-PANU NetworksRoundARP ResponseNumber of ARPNumberTimeoutrequests050 ms3
Group NetworksRoundARP ResponseNumber of ARPNumberTimeoutrequests050ms312seconds3
Note that a plurality of ARP requests per round is sent due to the fact that a wireless link (e.g. Bluetooth) is used, packets might be lost on the wireless link. This is a major difference to the wired network topology for which ZeroConf has to be initially implemented.
The waiting time in round 2 could be reduced, if the GN maintains a list of connected nodes and their MAC address and answer the request in behave of the addressed node. But to guarantee, that the algorithm works correct, the PANU must ensure that the GN supports this functionality. This could be checked with an additional layer 2—message exchange before the actual IP configuration is performed.
Network Access Point NetworksRoundARP ResponseNumber of ARPNumberTimeoutrequests02 seconds312 seconds322 seconds3
As has been shown above, it is the advantage of the present invention that the configuration process can be accelerated for network topologies having at least partial wireless network links. On the other hand, by sending out a plurality of ARP requests for cycle plurability of the process can be improved.

Network topology aware configuration of network addresses in wireless personal area networks

Abstract: According to the invention, this ZeroConf process is adapted to a network topology and link layer technology. Thereby, a plurality of pre-defined network topologies are used and the parameters of the ZeroConf process are adapted according to the decided network topology.


A system for displaying virtual content to a user includes at least one light source to multiplex a plurality of light beams to display a respective plurality of light patterns associated with one or more frames of image data. The system also includes a plurality of waveguides to receive the plurality of light beams and to direct the plurality of light beams toward an exit pupil, wherein the plurality of waveguides are stacked along an optical axis of the user. The system further includes at least one optical element to modify a focus of a light beam of the plurality of light beams directed by the plurality of waveguides.

Modern computing and display technologies have facilitated the development of systems for so called "virtual reality" or "augmented reality" experiences, wherein digitally reproduced images or portions thereof are presented to a user in a manner wherein they seem to be, or may be perceived as, real. A virtual reality, or "VR", scenario typically involves presentation of digital or virtual image information without transparency to other actual real-world visual input; an augmented reality, or "AR", scenario typically involves presentation of digital or virtual image information as an augmentation to visualization of the actual world around the user. As it turns out, the human visual perception system is very complex, and producing a VR or AR technology that facilitates a comfortable, natural-feeling, rich presentation of virtual image elements amongst other virtual or real-world imagery elements is challenging.
Referring to FIG. 2A, stereoscopic wearable glasses (8) type configurations have been developed which generally feature two displays (10, 12) that are configured to display images with slightly different element presentation such that a three-dimensional perspective is perceived by the human visual system. Such configurations have been found to be uncomfortable for many users due to a mismatch between vergence and accommodation which must be overcome to perceive the images in three dimensions; indeed, some users are not able to tolerate stereoscopic configurations. FIG. 2B shows another stereoscopic wearable glasses (14) type configuration featuring two forward-oriented cameras (16, 18) configured to capture images for an augmented reality presentation to the user through stereoscopic displays. The position of the cameras (16, 18) and displays generally blocks the natural field of view of the user when the glasses (14) are mounted on the user's head.
Referring to FIG. 2C, an augmented reality configuration (20) is shown which features a visualization module (26) coupled to a glasses frame (24) which also holds conventional glasses lenses (22). The user is able to see an at least partially unobstructed view of the real world with such a system, and has a small display (28) with which digital imagery may be presented in an AR configuration to one eye—for a monocular AR presentation. FIG. 2D features a configuration wherein a visualization module (32) may be coupled to a hat or helmet (30) and configured to present monocular augmented digital imagery to a user through a small display (34). FIG. 2E illustrates another similar configuration wherein a frame (36) couple-able to a user's head in a manner similar to an eyeglasses coupling so that a visualization module (38) may be utilized to capture images and also present monocular augmented digital imagery to a user through a small display (40). Such a configuration is available, for example, from Google, Inc., of Mountain View, Calif. under the trade name GoogleGlass®. None of these configurations is optimally suited for presenting a rich, binocular, three-dimensional augmented reality experience in a manner that will be comfortable and maximally useful to the user, in part because prior systems fail to address some of the fundamental aspects of the human perception system, including the photoreceptors of the retina and their interoperation with the brain to produce the perception of visualization to the user.
Referring to FIG. 3, a simplified cross-sectional view of a human eye (58) is depicted featuring a cornea (42), iris (44), lens—or "crystalline lens" (46), sclera (48), choroid layer (50), macula (52), retina (54), and optic nerve pathway (56) to the brain. The macula is the center of the retina, which is utilized to see moderate detail; at the center of the macula is a portion of the retina that is referred to as the "fovea", which is utilized for seeing the finest details, and which contains more photoreceptors (approximately 120 cones per visual degree) than any other portion of the retina. The human visual system is not a passive sensor type of system; it is configured to actively scan the environment. In a manner somewhat akin to use of a flatbed scanner to capture an image, or use of a finger to read Braille from a paper, the photoreceptors of the eye fire in response to changes in stimulation, rather than constantly responding to a constant state of stimulation. Thus motion is required to present photoreceptor information to the brain (as is motion of the linear scanner array across a piece of paper in a flatbed scanner, or motion of a finger across a word of Braille imprinted into a paper). Indeed, experiments with substances such as cobra venom, which has been utilized to paralyze the muscles of the eye, have shown that a human subject will experience blindness if positioned with his eyes open, viewing a static scene with venom-induced paralysis of the eyes. In other words, without changes in stimulation, the photoreceptors do not provide input to the brain and blindness is experienced. It is believed that this is at least one reason that the eyes of normal humans have been observed to move back and forth, or dither, in side-to-side motion in what are called "microsaccades".
As noted above, the fovea of the retina contains the greatest density of photoreceptors, and while humans typically have the perception that they have high-resolution visualization capabilities throughout their field of view, they generally actually have only a small high-resolution center that they are mechanically sweeping around a lot, along with a persistent memory of the high-resolution information recently captured with the fovea. In a somewhat similar manner, the focal distance control mechanism of the eye (ciliary muscles operatively coupled to the crystalline lens in a manner wherein ciliary relaxation causes taut ciliary connective fibers to flatten out the lens for more distant focal lengths; ciliary contraction causes loose ciliary connective fibers, which allow the lens to assume a more rounded geometry for more close-in focal lengths) dithers back and forth by approximately ¼ to ½ diopter to cyclically induce a small amount of what is called "dioptric blur" on both the close side and far side of the targeted focal length; this is utilized by the accommodation control circuits of the brain as cyclical negative feedback that helps to constantly correct course and keep the retinal image of a fixated object approximately in focus.
The visualization center of the brain also gains valuable perception information from the motion of both eyes and components thereof relative to each other. Vergence movements (i.e., rolling movements of the pupils toward or away from each other to converge the lines of sight of the eyes to fixate upon an object) of the two eyes relative to each other are closely associated with focusing (or "accommodation") of the lenses of the eyes. Under normal conditions, changing the focus of the lenses of the eyes, or accommodating the eyes, to focus upon an object at a different distance will automatically cause a matching change in vergence to the same distance, under a relationship known as the "accommodation-vergence reflex." Likewise, a change in vergence will trigger a matching change in accommodation, under normal conditions. Working against this reflex, as do most conventional stereoscopic AR or VR configurations, is known to produce eye fatigue, headaches, or other forms of discomfort in users.
Movement of the head, which houses the eyes, also has a key impact upon visualization of objects. Humans move their heads to visualize the world around them; they often are in a fairly constant state of repositioning and reorienting the head relative to an object of interest. Further, most people prefer to move their heads when their eye gaze needs to move more than about 20 degrees off center to focus on a particular object (i.e., people do not typically like to look at things "from the corner of the eye"). Humans also typically scan or move their heads in relation to sounds—to improve audio signal capture and utilize the geometry of the ears relative to the head. The human visual system gains powerful depth cues from what is called "head motion parallax", which is related to the relative motion of objects at different distances as a function of head motion and eye vergence distance (i.e., if a person moves his head from side to side and maintains fixation on an object, items farther out from that object will move in the same direction as the head; items in front of that object will move opposite the head motion; these are very salient cues for where things are spatially in the environment relative to the person—perhaps as powerful as stereopsis). Head motion also is utilized to look around objects, of course.
Further, head and eye motion are coordinated with something called the "vestibulo-ocular reflex", which stabilizes image information relative to the retina during head rotations, thus keeping the object image information approximately centered on the retina. In response to a head rotation, the eyes are reflexively and proportionately rotated in the opposite direction to maintain stable fixation on an object. As a result of this compensatory relationship, many humans can read a book while shaking their head back and forth (interestingly, if the book is panned back and forth at the same speed with the head approximately stationary, the same generally is not true—the person is not likely to be able to read the moving book; the vestibulo-ocular reflex is one of head and eye motion coordination, generally not developed for hand motion). This paradigm may be important for augmented reality systems, because head motions of the user may be associated relatively directly with eye motions, and the system preferably will be ready to work with this relationship.
Indeed, given these various relationships, when placing digital content (e.g., 3-D content such as a virtual chandelier object presented to augment a real-world view of a room; or 2-D content such as a planar/flat virtual oil painting object presented to augment a real-world view of a room), design choices may be made to control behavior of the objects. For example, the 2-D oil painting object may be head-centric, in which case the object moves around along with the user's head (e.g., as in a GoogleGlass approach); or the object may be world-centric, in which case it may be presented as though it is part of the real world coordinate system, so that the user may move his head or eyes without moving the position of the object relative to the real world.
Thus when placing virtual content into the augmented reality world presented with an augmented reality system, whether the object should be presented as world centric (i.e., the virtual object stays in position in the real world so that the user may move his body, head, eyes around it without changing its position relative to the real world objects surrounding it, such as a real world wall); body, or torso, centric, in which case a virtual element may be fixed relative to the user's torso, so that the user can move his head or eyes without moving the object, but that is slaved to torso movements; head centric, in which case the displayed object (and/or display itself) may be moved along with head movements, as described above in reference to GoogleGlass; or eye centric, as in a "foveated display" configuration, as is described below, wherein content is slewed around as a function of what the eye position is.
With world-centric configurations, it may be desirable to have inputs such as accurate head pose measurement, accurate representation and/or measurement of real world objects and geometries around the user, low-latency dynamic rendering in the augmented reality display as a function of head pose, and a generally low-latency display.
The systems and techniques described herein are configured to work with the visual configuration of the typical human to address these challenges.

Virtual and augmented reality systems and methods


An electric motor system for reducing drive wheel torque on a hybrid electric vehicle includes an internal combustion engine, an electric motor, a transmission, and a controller. The internal combustion engine is located in the hybrid electric vehicle and generates an engine torque. The electric motor is coupled to the internal combustion engine and generates and electric motor torque. Both the engine and motor are coupled to the transmission that uses the combined torque from both the engine and motor to generate drive wheel torque on a drive wheel. The vehicle system controller is coupled to the electric motor and senses any traction control events. When a traction control event occurs the controller commands the electric motor to reduce the drive wheel torque by reducing the electric motor torque.

Many production vehicles are equipped with traction control. Traction control prevents excessive drive wheel spin and therefore increases the stability and performance of the vehicle without compensation from the driver. Since wheel spin is due to a greater torque being applied to the wheels than the tractive limit of the tires for the given set of road conditions, a traction control event reduces the torque applied to the wheels.
Torque reduction is typically done by applying the brakes to the wheel or wheels that are spinning, as well as reducing the engine torque being applied. The engine torque reduction can be done several ways in a conventional vehicle: spark timing retard, fuel cutoff, and engine throttle. Of these alternatives, engine throttle is the most attractive when considering tailpipe emissions, fuel economy, NVH, and driver feel.
Unfortunately, engine transients, even with optimum AFR and spark timing, are a major contributor to tail pipe emissions due to physical and control time delays. Additionally, the engine must operate at less then an optimum condition during these traction control events. Also, in a conventional vehicle, the torque reduction due to each actuator must be calculated to determine the total torque reduction necessary from the engine. These calculations introduce errors and time to perform tasks may introduce significant wheel torque errors.
The disadvantages associated with this conventional torque control technique have made it apparent that a new technique for traction control for a hybrid electric vehicle is needed. Preferably, the new technique would allow the engine to continue operating at its optimum level during traction control events without negatively affecting tailpipe emissions, NVH or fuel economy.

Traction control system for a hybrid electric vehicle


A pipeline supported by a plurality of spaced, movable supports. The supports are not anchored but are movable with respect to the surface of the earth (e.g. tundra) thereby allowing the pipeline to move in response to temperature/pressure changes in said pipe. The supports are sized so that the pipeline will be elevated above the surface of the tundra at a height sufficient to allow water to flow under the pipeline as well as allowing small animals to pass thereunder. The movable supports may be either rolling supports which lie directly on the surface or sliding supports which are positioned on slidable stands or combination of both.

The present invention relates to supports for pipelines and in one aspect relates to movable supports spaced along a pipeline wherein the supports are laid on the ground to elevate the pipeline so that water or small wildlife can readily pass thereunder but at the same time allow the pipeline to move freely in response to thermal expansion/contraction or pressure surges.
The concept of laying a flexible pipeline directly on the ground in a remote area (e.g. on tundra in arctic regions) is attractive in that it has several inherent advantages. First, the cost of trenching and burying the line or supporting the pipeline above the ground on xe2x80x9cpermanentxe2x80x9d pilings or supports is eliminated. Second, access to a pipeline lying directly on the ground is very easy since no digging or scaffolding is required when maintenance is required. Finally, the pipeline can be moved or removed much easier and at much less expense than a line that is buried or elevated on permanent pilings while, at the same time, causing much less damage to the existing environment.
Unfortunately, however, there are some disadvantages in laying a pipeline directly on the ground. For example, during rainy weather or a spring thaw, the pipeline functions as an artificial dam, creating a small xe2x80x9criverxe2x80x9d along the pipeline right of way which, in turn, can cause serious erosion problems. Also, due to the size of some pipelines, certain small animals may have trouble crossing the lines.
In order to provide ready access to a pipeline and at the same time allow water and small wildlife (e.g. molting birds, etc.) to readily pass under the pipeline, it has been proposed to support the pipeline on spaced, low-profile supports such as railroad ties or the like. However, this type of support is not free to move with the pipe if and when the pipe undergoes movement (e.g. temperature expansion/contraction, pressure surges, etc.) during operation. This rubbing of the pipe against the support can lead to serious damage to the surface (e.g. tundra) under the support as well as possible damage to the pipeline, itself. Further, xe2x80x9crailroad-tiexe2x80x9d types of support may be difficult to install in extremely remote or rugged terrain since they normally require a wide, flat area to be effective.
The present invention provides a pipeline for conveying fluids which is comprised of a length of pipe which is supported by a plurality of movable supports which, in turn, are positioned around said pipeline at spaced intervals along the pipeline. The supports are movable with respect to the surface of the earth (e.g. tundra) thereby allowing said pipeline to move in response to temperature/pressure changes in said pipe. The supports are sized so that the pipeline will be elevated above the surface of the tundra at a height sufficient to allow water to flow under the pipeline as well as allowing small animals to pass thereunder.
More specifically, the movable supports may be rolling supports or sliding supports or preferably a combination of both. A rolling support in accordance with the present invention is comprised of a cylindrical shell which has a central bore therethrough which, in turn, is adapted to receive the pipe. The diameter of the central bore is larger than the outside diameter of the pipe whereby the pipeline is free to move longitudinally within the cylindrical shell. Preferably, the cylindrical shell is comprised of two substantially identical halves (e.g. formed from a plastic material) which are adapted to be secured together after they have been positioned around the pipe. One half of the cylindrical shell is adapted to lie directly on the ground after it has been assembled onto the pipeline.
Each sliding supports of the present invention is comprised of a slidable stand which, in turn, is comprised a saucer-like, partial-spherical base which is adapted to be positioned in movable contact with said surface of the tundra. A plurality of vertical members are affixed to the base and extending upward therefrom. A cylindrical shell, similar to that of a rolling support is positioned on and supported on the vertical members whereby the cylindrical shell will move with said base. Again, the cylindrical shell is comprised of two substantially identical halves which have a central bore therethrough when assembled in which the pipeline is received. The diameter of said central bore is substantially equal to the outside diameter of the pipe whereby the pipeline will be clamped within said central bore when said halves of said cylindrical shell are assembled around said pipe. This tight fit prevents the pipe from moving longitudinally with respect to said cylindrical shell.
In constructing the pipeline, a plurality of the movable supports are spaced along the length of the line. Since the supports are not anchored to the surface, they are free to move in response to any pressure surges in the line or any expansion/contraction of the pipeline due to temperature changes. The rolling supports will xe2x80x9crollxe2x80x9d across the tundra while the sliding supports will xe2x80x9cslidexe2x80x9d and/or xe2x80x9crockxe2x80x9d in response to any significant changes in the pipeline thereby substantially elimination any possible damage to either the pipeline or the tundra.


In process for producing detergent particles, an acid precursor of an anionic surfactant and a neutralizing agent are fed into a horizontal thin-film evaporator/drier where they are neutralized, granulated and dried. The neutralizing agent is present in an amount equal to or in excess that required for stoichiometric neutralization and has a D50 mean particle size of less than 40 xcexcm.

The present invention relates to a process for the production of anionic detergent particles and detergent compositions containing them. More particularly the present invention relates to a process for the production of detergent particles having a high level of anionic surfactant which involves in situ neutralisation of an acid precursor of the anionic surfactant and drying of the surfactant thereby produced.
It is known that detergent particles having high anionic surfactant levels can be prepared by processes in which acid precursors of anionic surfactants are neutralised with a neutralising agent in horizontal thin-film evaporator/drier (WO-A-96/06916, WO-A-96/06917 and WO-A-97/32002; WO-A-98/38278 and WO-A-98/40461) and the mass is granulated and dried. As used herein, the term thin-film evaporator/drier is understood to include flash-driers and scraped-surface driers as described in WO-A-96/06916, WO-A-96/06917 and WO-A-97/32002.
Basically, a thin-film evaporator/drier comprises a cylindrical chamber in which is located a coaxial shaft on which is mounted a plurality of blade-like tools. The pitch of these tools can be set to different angles along the length of the cylindrical chamber, from input end to output end. The clearance between the tips of the blade-like tools and the internal surface of the cylindrical chamber is very small, typically 5 mm or less. The cylindrical chamber comprises at least a mixing region at or towards the input end of the cylindrical chamber, a cooling region at or towards the output end of the cylindrical chamber and a drying region between the mixing and cooling regions. The drying region typically comprises one or more heating zones and the cooling region may comprise one or more cooling zones (although usually only one cooling zone. Each of the heating and cooling zones is defined by a respective jacket around the cylindrical chamber with a respective axial gap between each and through which jackets, a heating or cooling liquid, as appropriate, is pumped during operation of the process. The layering agent is  typically an aluminosilicate or a silica.
A problem associated with processes which involve the neutralisation of anionic surfactant acid precursors (hereinafter referred to as  acid precursors) is that of incomplete neutralisation. Even relatively small levels free acid in the resulting detergent particles can result in the following:-
(i) softer particles which are more difficult to handle and store;
(ii) the generation of heat during storage as the neutralisation reaction continues;
(iii) the free acid in the detergent particles reacting with other ingredients (e.g. perfumes) in detergent compositions of which the detergent particles are a component; and
(iv) increased uptake of moisture upon storage, due to the hygroscopicity of many acid precursors, resulting in poor powder flow properties both of the detergent particles and of detergent compositions containing the detergent particles.
The problems associated with incomplete neutralisation are especially prevalent when neutralising linear alkyl benzene sulphonic acid (LAS acid) precursors and alkyl sulphuric acid half-esters.
WO-A-97/32002 discloses a dry-neutralisation process in which high anionic surfactant-content detergent particles are manufactured by contacting a pumpable acid precursor with a solid neutralising agent, such as for example sodium carbonate, in a thin-film evaporator/drier.
EP-A-555 622 describes the manufacture of detergent particles comprising anionic surfactant in which acid precursors are neutralised in a high shear mixer by a stoichiometric excess of particulate neutralising agent, preferably sodium carbonate. The neutralisation reaction is optimised by using neutralising agent of a narrowly defined particle size range, namely 50% by volume has a particle diameter of less than 5 microns.
EP-A-555 622 does not, however, relate to the production of high anionic surfactant-content detergent particles or to the use of thin-film evaporator/driers. According to the teaching of this reference, the neutralising agent is preferably present in an amount of at least five times that required for stoichiometric neutralisation. In addition, the ratio of liquid ingredients (e.g. acid precursor) to powder ingredients (e.g. neutralising agent) introduced into the high shear mixer is most preferably from 1:2 to 1:3. It is not possible to make high anionic surfactant-content detergent particles using such excesses of neutralising agent and/or liquid to solid ratios. Indeed, the detergent particles of the examples contain merely 23 wt % anionic surfactant.
We have now found that the level of neutralisation in a dry-neutralisation process can be significantly improved when making high anionic surfactant-content detergent particles using a thin-film evaporator/drier by employing a particulate neutralising agent of relatively small particle size in an amount excess to that required for stoichiometric neutralisation and having a D50 average diameter of less than 40 xcexcm.
A first aspect of the present invention provides a process for the production of detergent particles comprising feeding an acid precursor of an anionic surfactant and a neutralising agent into a horizontal thin-film evaporator/drier and neutralising, granulating and drying the material in the evaporator/drier, the neutralising agent is being fed in an amount equal to or in excess to that required for stoichiometric neutralisation and having a D50 mean particle size of less than 40 xcexcm, preferably less than 30 xcexcm, more preferably less than 20 xcexcm, especially less than 10 xcexcm.
A second aspect of the present invention also provides detergent particles obtainable by the process of the first aspect of the invention.
The process is carried out in a horizontal thin-film evaporator/drier (hereinafter referred to as an evaporator/drier). A commercial scale machine typically comprises at least 300, preferably at least 500, more preferably at least 750, especially at least 1000 blade-like tools. The clearance between the blades and the internal wall of the chamber is suitably less than 20 mm, e.g. 15 mm or less, or even 10 mm or less. The blade tip speed in operation is suitably xe2x89xa715 msxe2x88x921, preferably xe2x89xa720 msxe2x88x921. The ratio of exposed blade length to shaft radius is preferably less than 1, e.g. less than 0.5. Preferably, the large number of blades and the pitch of the blades also means that at least 40%, for example at least 45%, and even substantially the whole chamber wall (that part along the length of the shaft which carries the blades) is scraped during operation.
Initial mixing of the components occurs in the mixing region and the neutralisation reaction is begun. Mixing and neutralisation then continue throughout the process, through the drying and cooling regions.
The anionic surfactant acid precursor (hereinafter referred to as the acid precursor) and neutralising agent are normally fed into the mixing region of the evaporator/drier. However, all or part of either component can be dosed into the drying region. Neutralisation occurs to form a surfactant paste, which is then converted into detergent particles by the drying and mechanical action of the evaporator/drier. The evaporator/drier exerts its drying action by forming a thin layer of material on a heated surface within the drying region.
The acid precursor is suitably fed into the evaporator/drier in a liquid phase. As acid precursors can be unstable, the neutralisation preferably occurs sufficiently rapidly and substantially completely such that thermal decomposition of the acid due to elevated temperature is minimised and desirably avoided.
The neutralising agent is introduced into the evaporator/drier as a solid particulate material. Preferably, the amount of neutralising agent with respect to the acid precursor added to the mixing region is at least in stoichiometric equality, most preferably in excess. Preferably, at least 1.25 times required for stoichiometric neutralisation is used but preferably no more than 2 times. Higher amounts of neutralising agent, e.g. no more than 5 times, no more than 4.5 times, or no more than 4 times that required for stoichiometric neutralisation can be used but these higher amounts are generally less preferred.
The acid precursor and neutralising agent may be added as a single stream to the evaporator/drier, or as two or more streams.
The drying region of the evaporator/drier basically comprises a tube which is substantially circular in cross section and is thus defined by a cylindrical wall. The material entering the drying region is heated. Typically this is achieved by heating the wall of the drying region by means of a heating jacket through which water, steam or oil may be fed.
The drying region may be divided into a number of heating zones, each heated to the same or a different temperature, preferably by means of a respective heating jacket. The temperature in the drying region is preferably maintained at at least 100xc2x0 C., more preferably at at least 120xc2x0 C., yet more preferably at at least 130xc2x0 C. Higher temperatures are possible, but it will be understood by the skilled person that it is preferable not to exceed the thermal decomposition temperature of the acid precursor or the anionic surfactant formed therefrom. Depending on the detergent active, temperatures up to 170xc2x0 C. or even up to 180xc2x0 C. are employed.
It has been found to be highly advantageous in the process of the invention to pass the material leaving the drying region of the evaporator/drier through a cooling region. The cooling region may be provided by a separate piece of apparatus, such as for example a cooling fluid bed, an airlift alternatively, may form part of the evaporator/drier apparatus.
The cooling region is preferably operated at a temperature not in excess of 50xc2x0 C. and more preferably not in excess of temperature 40xc2x0 C., e.g. 30xc2x0 C. Actively cooling the particles reduces the possibility of thermal decomposition occurring due to particles being heated to a high temperature. In addition, actively cooling reduces the risk of particles sticking/clumping which may occur when heated particles are allowed to cool passively.
Preferably, the cooling region is defined by a cylindrical wall which is cooled, for example, by a cooling jacket. Where the process is continuous, the evaporator/drier and the cooling region are suitably arranged so that the drying region and cooling region are substantially horizontally aligned to facilitate efficient drying, cooling and transport of the material through the drying region and cooling region in a generally horizontal direction.
In a preferred embodiment, the evaporator/drier apparatus includes the cooling region positioned after the drying region, and the cooling region is a tube which is substantially circular in cross section and is thus defined by a cylindrical wall. When such evaporator/drier apparatus is employed, a suitable temperature gradient is set up going from, for example, at least 100xc2x0 C. at the inlet end to, for example, not more than 80xc2x0 C. at the outlet end.
Agitation of the materials in the drying region generally provides efficient heat transfer and facilitates removal of water. Agitation reduces the contact time between the materials and the wall of the drying region, which, together with efficient heat transfer, reduces the likelihood of hot spots forming which may lead to thermal decomposition. Moreover, improved drying is secured thus allowing a shorter residence time and increased throughput in the heating zone(s).
Preferably, the cooling region is also provided with agitation means to effect efficient cooling of the material therein. This may be a fluidising gas in a cooling fluid bed. Alternatively, where the cooling region is part of the evaporator/drier apparatus, it is preferred to use the same rotating agitation means as defined above in relation to the drying region.
It will be understood that the cooling region may comprise more than one cooling zone.
In a preferred embodiment, drying and cooling regions together comprise three zones defined by a cylindrical wall, the first two zones being heating zones defining the drying region, and the third zone being the cooling region. Acid precursor and neutralising agent are fed in to the first zone and rotating agitation means comprising a series of radially extending paddles and/or blades mounted on a axially mounted rotatable shaft agitates and transports material through the heating and cooling zones to produce detergent particles.
Preferably, the evaporator/drier is operated at atmospheric pressure in counter-current or co-current with a gas stream at a throughput rate of 10-150 m3 per hour. The gas stream may simply be air, which may have been dried so as to reduce its moisture content, or may be a gas stream having an alkaline pH, such as for example a mixture of ammonia and air.
The process of the invention is preferably continuous as this facilitate continuous transportation of the particles.
Suitably the total average residence time in the drying region is from 30 seconds to 15 minutes, preferably from 1 minute to 12 minutes, more preferably from 2 minutes to 8 minutes. The average residence time may be determined by injecting a coloured tracer and plotting a concentration profile for the tracer exiting the drying region. The average residence time is taken as the value corresponding to 50% of the total area under the curve. Preferably, the measurement is repeated a suitable number of times.
Advantageously, oversize particles from the output of the process may be recycled to be input to the evaporator/drier. Preferably, an oversize granule fraction is separated from the output particles such that at least 70 wt % of the particles in the oversize fraction have a minimum diameter of 1000 xcexcm or more. Most preferably, at least 95 wt % have a minimum diameter of 700 xcexcm or more. Minimum particle diameter may be considered as the smallest particles which will not pass through a sieve of a mesh which retains particles of the relevant size or larger. Preferably, the oversize fraction is fed back into the mixing and/or drying region and/or between the two.
The process of the invention may be carried out in any suitable apparatus. Suitable thin-film evaporator/drier apparatus include the Flash Dryer/Reactor manufactured by VRV, the Turbodryer manufactured by VOMM and a similar machine available from Bipex Hosokawa.
Prior to neutralisation and drying, the anionic surfactants are present and fed into the drying region of the evaporator/drier in their acid precursor form. The acid precursor can either be fed as an aqueous preparation or in anhydrous form. If added as an aqueous preparation, it is preferred that the water content does not exceed 25% by weight, more preferably not exceeding 10% by weight.
Suitable acid precursors include:
linear alkyl benzene sulphonic acids (LAS acids) which give linear alkyl benzene sulphonates (LAS) upon neutralisation. Preferably, any LAS anionic surfactant has a chain length of C8-18, more preferably C9-15 and most preferably C10-14.
alkyl and/or alkenyl sulphuric acid half-esters (i.e. the sulphation products of primary alcohols) which give alkyl and/or alkenyl sulphates upon neutralisation. The present invention has especial applicability in the production of detergent particles comprising PAS having a chain length of C10-22, preferably C12-14; Coco PAS is particularly desirable.
carboxylic acids which give soaps upon neutralisation. Preferred carboxylic acids are fatty acids with 12-18 carbon atoms, such as for example fatty acids of coconut oil, palm oil, palm kernel and tallow.
Other suitable acid precursors include alphaolefin sulphonic acids, internal olefin sulphonic acids, fatty acid ester sulphonic acids and primary sulphonic acids.
It is also possible to use combinations of various acid precursors as will be apparent to the skilled person.
The neutralising agent is a particulate base material capable of neutralising the acid precursor. In principle, any alkaline inorganic material can be used for the neutralisation but water-soluble alkaline inorganic materials are preferred. It has a D50 particle size less than 40 xcexcm, preferably less than 20 xcexcm, especially less than 10 xcexcm. D50 refers to the value of particle size corresponding to 50% weight percent of the particles on a size distribution curve (i.e. half of the area under the curve is to the right of this value, and half to the left).
Suitable neutralising agents include any salts of hydroxides, carbonates, bicarbonates and silicates and mixtures thereof. Suitably, the sodium, potassium, calcium or magnesium salts may be used. However, the sodium salt is preferred.
A preferred neutralising agent is sodium carbonate alone or in combination with one or more other water-soluble inorganic materials, for example, sodium bicarbonate or silicate.
Particles of the neutralising agent having the required D50 mean particle size may be obtained by dry milling of commercially available particulate neutralising agent of larger D50 mean particle size, e.g. using a hammer or pin mill.
In addition to the acid precursor and neutralising agent, other liquid and solid components may be fed to the drying region of the evaporator/drier, and/or the cooling zone if present. For example, pre-neutralised surfactants, may be fed into the drying region as separate streams and/or as an admixture with the neutralising agent and/or acid precursor.
However, it is desirable that the weight ratio of the total liquid ingredients to the total solid ingredients fed to the drying region of the evaporator/drier, or, where a cooling zone is employed, to the drying zone and cooling zone, is in the range 2:1 to 6:1, preferably from 3:1 to 5:1.
The detergent particles preferably have an anionic surfactant content of at least 25%, more preferably 40% by weight. The present process can be used to make detergent particles with a anionic surfactant content of at least 50%, 60% or 70% by weight. The maximum amount is typically 90%, preferably 85% by weight.
It is desirable that the particles also comprise water in an amount of 0 to 8% and preferably 0 to 4% by weight of the particles.
Other non-surfactant components which may be present in the detergent particles include dispersion aids, preferably polymeric dispersion aids and more preferably urea, sugars, polyaklyleneoxides; and builders as hereinafter described.
If desired the detergent particles may comprise an organic and/or inorganic salt, e.g. a hydratable salt. Suitable materials in salts, preferably sodium, of tripolyphosphate, citrates, carbonates, sulphates, chlorides. Aluminosilicates, clays, silicas and other inorganic materials may also be included.
The particles may also contain one or more nonionic surfactants, for example as mentioned below in the context of a base powder with which the particles are admixed.
Similarly, organic materials, e.g. PEG and other polymer builder or soap may also be included in the particles, also as mentioned below in the latter context.
Desirably the detergent particles have an aspect ratio not in excess of 2 and more preferably are generally spherical in order to reduce segregation from other particles in a formulated detergent composition and to enhance the visual appearance of the powder.
The detergent particles can be coated by adding a layering agent either at the output end of the drying region of the evaporator/drier, in the cooling region, or in an additional step, e.g. on a vibrating conveyer belt. It is particularly preferred to add layering agent in the cooling region.
The layering agent may be any material capable of coating the particles in order to improve the granularity thereof. Relatively inert materials are preferred for this purpose but especially any of those inert materials which have a beneficial effect in the wash liquor, for example, aluminosilicates, silicas talcs and clays. A mixture of such materials may be used. Examples of aluminosilicates and silicas are outlined in more detail hereinbelow. The presence of any such material as a coating on the finished particles does not preclude the presence also of the material within the body of the particles.
In the case of aluminosilicates, these may be partly or solely dosed earlier in the process, i.e. not completely,or not at all, as layering agents. A particularly suitable way of implementing this is to feed an acid precursor of an anionic surfactant, a neutralising agent and aluminosilicate detergency builder into the horizontal thin-film evaporator/drier comprising a mixing region, a drying region and a cooling region, to effect neutralisation of the acid precursor, granulation, drying and cooling, to form the said detergent particles, wherein at least some of the aluminosilicate builder is fed into the thin-film evaporator/drier between the drying region and the cooling region and/or into the cooling region. Optionally, when all of the aluminosilicate builder is fed into the cooling region, the aluminosilicate is in an amount of more than 20% by weight of the particles exiting the cooling region.
Relative to the total other materials of the particles, the dosing weight ratio of the layering materials, e.g. added in the cooling zone, is preferably from 1:3 to 1:20, more preferably from 1:9 to 1:20.
The detergent particles may be post-dosed to (admixed with) another powder obtained from any conventional detergent production process including spray drying or non spray-drying processes in which the components of the detergent composition are mixed and granulated as described e.g. in EP-A-367 339 and a spray drying process optionally followed by a post tower densification. For convenience, such other powder is hereinafter called a base powder. As the detergent particles produced by the present invention may be admixed with such other powders, a significant degree of formulation flexibility is obtained and the level of active material in the fully formulated composition may be very high as desired. A further advantage is that a base powder which is substantially free of detergent active compounds may be produced and the detergent active compounds may be introduced substantially wholly from the particles obtained by the process of the present invention.
The option of reducing the level of detergent active material in a base powder is especially advantageous where the base powder is produced by a spray drying process as a lower level of detergent active compound in the spray drying process permits a higher throughput to be secured thus increasing overall production efficiency.
Compositions according to the present invention may also contain, in addition to the detergent-active compound, a detergency builder and optionally bleaching components and other active ingredients to enhance performance and properties.
Detergent compositions of the invention may contain, in addition to the post-dosed detergent particles, one or more detergent-active compounds (surfactants) which may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent-active compounds, and mixtures thereof. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in Surface-Active Agents and Detergents, Volumes I and II, by Schwartz, Perry and Berch. The preferred detergent-active compounds that can be used are soaps and synthetic non-soap anionic and nonionic compounds.
Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C8-C15; primary and secondary alkyl sulphates, particularly C12-C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8-C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles ethylene oxide per mole of alcohol, and more especially the C10-C15 primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).
The total amount of surfactant present in the detergent composition is suitably from to 5 to 40 wt % although amounts outside this range may be employed as desired.
The detergent compositions of the invention generally also contain a detergency builder. The total amount of detergency builder in the compositions is suitably from 10 to 80 wt %, preferably from 15 to 60 wt %. The builder may be present in an adjunct with other components or, if desired, separate builder particles containing one or more builder materials may be employed.
Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB-A-1 437 950. Of course, such carbonate materials conveniently are introduced as some or all of the neutralising agent. Other suitable inorganic builders include crystalline and amorphous aluminosilicates, for example zeolites as disclosed in GB-A-1 473 201; amorphous aluminosilicates as disclosed in GB-A-1 473 202; and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250; and layered silicates as disclosed in EP-B-164 514. Inorganic phosphate builders, for example, sodium, orthophosphate, pyrophosphate and tripolyphosphate, may also be present, but on environmental grounds those are no longer preferred.
Aluminosilicates, whether used as layering agents and/or incorporated in the bulk of the particles may suitably be present in a total amount of from 10 to 60 wt % and preferably an amount of from 15 to 50 wt %. The zeolite used in most commercial particulate detergent compositions is zeolite A. Advantageously, however, maximum aluminium zeolite P (zeolite MAP) described and claimed in EP-A-384 070 may be used. Zeolite MAP is an alkali metal aluminosilicate of the P type having a silicon to aluminium ratio not exceeding 1.33, preferably not exceeding 1.15, and more preferably not exceeding 1.07.
Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. A copolymer of maleic acid, acrylic acid and vinyl acetate is especially preferred as it is biodegradable and thus environmentally desirable. This list is not intended to be exhaustive.
Especially preferred organic builders are citrates, suitably used in amounts of from 5 to 30 wt %, preferably from 10 to 25 wt %; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt %, preferably from 1 to 10 wt %. The builder is preferably present in alkali metal salt, especially sodium salt, form.
Suitably the builder system comprises a crystalline layered silicate, for example, SKS-6 ex Hoechst, a zeolite, for example, zeolite A and optionally an alkali metal citrate.
Detergent compositions according to the invention may also contain a bleach system, desirably a peroxy bleach compound, for example, an inorganic persalt or organic peroxyacid, capable of yielding hydrogen peroxide in aqueous solution.
The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. An especially preferred bleach system comprises a peroxy bleach compound (preferably sodium percarbonate optionally together with a bleach activator), and a transition metal bleach catalyst as described and claimed in EP 458 397A and EP-A-509 787.
The compositions of the invention may contain alkali metal, preferably sodium, carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in an amount from 1 to 60 wt %, preferably from 2 to 40 wt %. However, compositions containing little or no sodium carbonate are also within the scope of the invention.
Powder flow may be improved by the incorporation of a small amount of a powder structurant, for example, a fatty acid (or fatty acid soap), a sugar, an acrylate or acrylate/maleate polymer, or sodium silicate which is suitably present in an amount of from 1 to 5 wt %.
The materials that may be present in detergent compositions of the invention include sodium silicate; corrosion inhibitors including silicates; antiredeposition agents such as cellulosic polymers; fluorescers; inorganic salts such as sodium sulphate, lather control agents or lather boosters as appropriate; proteolytic and lipolytic enzymes; dyes; coloured speckles; perfumes; foam controllers; and fabric softening compounds. This list is not intended to be exhaustive.
The base composition is suitably prepared by spray-drying a slurry of compatible heat-insensitive ingredients, and then spraying on, admixing and/or postdosing those ingredients unsuitable for processing via the slurry. The detergent particles produced according to the process of the present invention are post-dosed to the base composition by conventional methods.
Detergent compositions of the invention preferably have a bulk density of at least 500 g/l, more preferably at least 550 g/liter.
Such powders may be prepared either by spray-drying, by post-tower densification of spray-dried powder, or by wholly non-tower methods such as dry mixing and granulation. A high-speed mixer/granulator may advantageously be used for such mixing. Processes using high-speed mixer/granulators are disclosed, for example, in EP-A-340 013, EP-A-367 339, EP-A-390 251 and EP-A-420 317.
The invention is illustrated by the following non-limiting Examples.

Production of anionic surfactant granules by in situ neutralization

Unilever Home and Personal Care USA, division of Conopco, Inc.


A humidifier 10 has a water circuit 20 that switches the flow of water between a first flow state, in which hot water introduced from a first inlet 21 flows through a first heat exchanger 32 and flows to a first outlet 22 and in which cold water introduced from a second inlet 23 flows through a second heat exchanger 42 and flows to a second outlet 24, and a second flow state, in which the hot water introduced from the first inlet 21 flows through the second heat exchanger 42 and flows to the first outlet 22 and in which the cold water introduced from the second inlet 23 flows through the first heat exchanger 32 and flows to the second outlet 24. The water circuit 20 has a bypass passage 36 for connecting the inlets 21, 23 to the outlets 22, 24 respectively at the time of switching the flow of water. With this, even if the respective three-way valves 31, 33, . . . cause a faulty operation, the cold water and the hot water surely flow through the bypass passage 36 and flow to the respective outlets 22, 24.

1. Technical Field
The present invention relates to a humidifier and, in particular, to protective measures of piping and the like of a humidifier having a water circuit and performing a batch operation.
2. Related Art
There has been known a humidifier that adjusts the humidity of air by the use of an adsorbent and a refrigeration cycle (for example, see patent document 1).
A humidifier disclosed in the patent document 1 has two adsorbing devices each having an adsorbent and a refrigerant circuit for performing a refrigeration cycle. This humidifier performs a first operation that dehumidifies first air by a first adsorbing device and that reproduces a second adsorbing device by second air heated by a condenser of the refrigerant circuit and a second operation that humidifies the first air by the second adsorbing device and that reproduces the first adsorbing device by the second air heated by the condenser. These two operations are alternately performed, whereby the dehumidified first air or the humidified second air is supplied into the room.
On the other hand, it can be thought to use an adsorption heat exchanger in which the adsorbing device and a heat exchanger are combined in one unit having the adsorbent supported thereon. In this case, the adsorption heat exchanger is constructed of a so-called fin-and-tube type heat exchanger having many plate-shaped fins and a copper pipe passing through the fins. The adsorbent is supported on the surfaces of the fins and the copper pipe. This heat exchanger dehumidifies and humidifies air flowing therethrough by the adsorbent and heats and cools the adsorbent by refrigerant flowing through the copper pipe.
Further, a humidifier can be thought that uses a water circuit, in which cold water and hot water flow, in place of the refrigerant circuit. In other words, the cold water and the hot water are alternately flowed through the adsorption heat exchanger to cool and heat the adsorbent.    Patent document 1: Japanese Unexamined Patent Publication No. 2004-60954


A soldering flux includes a solvent, an activator in the solvent, and cationic and nonionic surfactants. The soldering flux can be applied to a substrate, such as a printed circuit board before solder is applied.

The present invention relates to soldering flux compositions useful in soldering applications for electronic assemblies such as printed wiring boards.
The manufacture of printed circuit boards (PCBs), also referred to as printed wiring boards (PWBs), is typically divided into two processing categories, fabrication and assembly. Towards the end of the PCB fabrication process, after plating and etching, most of the PCB is covered with a solder mask. The solder mask is used to protect masked areas of the PCB from the attachment of solder. Accordingly, areas of the PCB that will later be soldered, such as the pads and holes, are not covered with the mask.
In a first step of the assembly process, both through-hole and surface mount components, such as integrated circuits, connectors, dual in-line packages, capacitors and resistors, are oriented with the PCB. For example, a component with leads may be mounted on the PCB by placing its leads through holes in the board. Surface mount components can be attached to the board""s bottom side (i.e., the surface to be soldered) using adhesive. The components are then ready to be soldered to the PCB to ensure reliable electrical continuity between the components and PCB circuitry. The component leads and terminations or pads can be soldered via a wave solder process.
The wave solder process includes the steps of fluxing, preheating and soldering. In the fluxing step, a flux is used to prepare the surfaces to be soldered. Such preparation is generally needed because the PCB and the components can become contaminated as a consequence of having been stored in a non-clean-room environment before the soldering process. In addition, oxides may have formed on the leads, terminations and/or pads. In addition to reacting with or removing contaminants and oxides, the flux can perform other functions, such as protecting the surfaces from re-oxidation and reducing the interfacial surface tension between the solder and the substrate to enhance wetting.
Typically, a spray, foam or wave fluxing process is used to apply the flux onto the PCB and component surfaces to be soldered. The fluxing procedure is followed by a preheating step to evaporate the solvent carriers in the flux, such as alcohols or water, and to begin heating the surfaces to be joined. The preheat step is followed by a wave solder process in which the PCB, with components mounted thereon, is passed over a wave of molten solder. The solder wave is pumped through a nozzle; and the wave then contacts and deposits solder on the surface to be joined. The deposited solder then serves to bond and electrically connect the leads and terminations of the components with the contacts on the PCB.
Many of the existing low-solids, no-clean soldering fluxes cause an excessive number of solder balls to be left on the PCB surface. These fluxes also cause solder bridging because their surface tensions are too high. In addition, due to their weak activity levels, the fluxes are unable to thoroughly remove the tarnish and oxides from the surfaces to be joined. Solder balls are unwanted balls of solder occurring randomly or non-randomly on the solder mask and/or between the leads of the components on the board; the solder balls can bridge a gap between two conductors resulting in an electrical short. Solder bridges are connections of unwanted solder that can form a short circuit between two traces or leads that were not designed to be connected. Solder bridges and/or solder balls may cause electrical failure of the board. Excessive solder balls and bridging also require costly solder touch-up operations for their removal. Even tiny solder balls, often referred to as micro-solder balls, because they are only visible with magnification (e.g., 10 times magnification), can result in electrical shorting of very-closely-spaced board lines and pads as well as component leads and terminations. Another problem with existing fluxes is that they can leave visible residues on the surfaces of the PCB, which in addition to being unsightly, can cause false rejects with in-circuit pin testing.
Thus, a need exists for a soldering flux composition that effectively prepares the surfaces to be joined and that reduces the number of solder balls and solder bridges by reducing the surface tension between the PCB surfaces, component leads/terminations and molten solder without increasing the amount of visible residue.
Described herein are fluxes offering reduced-micro-solder-balling, low-residue, low-solids, and no-clean capability. The fluxes include a solvent, an activator in the solvent, a cationic surfactant and a nonionic surfactant. The fluxes are particularly useful for coating a PCB prior to application of solder.
In one embodiment, the solvent is an alcohol, such as isopropyl alcohol. The cationic surfactant can be a quaternary ammonium fluoroalkyl surfactant. The nonionic surfactant can be a nonylphenoxypolyethoxyethanol surfactant. The activator can be a combination of a dicarboxylic acid and a nonionic brominated compound. A printed circuit board coated with a flux described herein includes a substrate on which conductive pathways and conductive contacts, typically formed of metal, are printed and electrically coupled. The flux is coated on the conductive contacts; then solder is applied onto the flux and the board. The solder provides electrical coupling between the contacts and components fixed to the PCB.
Fluxes described herein offer a variety of advantages. The fluxes can effectively remove metal oxides from the PCB surfaces to be soldered so as to promote solder wetting. The fluxes can also substantially lower the interfacial surface tension between the PCB surfaces and a molten solder alloy, thereby promoting drainage of excess solder from the board surface and consequently reducing solder-ball and solder-bridge formation. Moreover, the fluxes can reduce the amount of visible flux residue formed during the wave soldering process.
The soldering flux composition incorporates one or more cationic surfactants, one or more nonionic surfactants and activators dissolved in volatile solvent, such as isopropyl alcohol, ethyl alcohol, de-ionized water or mixtures thereof. Suitable concentration ranges (by weight percent) for these components in the flux composition are as follows: 50-98% solvent, 0.2-10% activator, 0.01-1.0% cationic surfactant, and 0.05-10% nonionic surfactant. In particular embodiments, the concentration range (by weight percent) for each of the above-mentioned components is as follows: 75-98% solvent, 0.2-5.0% activator, 0.05-0.5% cationic surfactant, and 0.10-2.0% nonionic surfactant. One or more high-boiling-point additives can also be incorporated into the flux composition, e.g., at a concentration of 0.2-25% by weight.
A cationic quaternary ammonium fluoroalkyl surfactant, such as FLUORAD FC-135 surfactant (manufactured by 3M Co. of St. Paul, Minn.), SURFLON S-121 surfactant (manufactured by Seimi Chemical Co., Japan), or Neos FTERGENT 300 surfactant (manufactured by Neos, Japan), is used to substantially reduce flux residues as well as the surface tension of the board surface and molten solder alloy. Consequently, the volume of random and non-random solder balls on the board surfaces is also reduced. Ammonium or amine fluoroalkyl surfactants that include an aromatic sulfone functional group (such as Neos FTERGENT 300 surfactant, which is a cationic quaternary ammonium fluoroalkyl compound with an aromatic sulfone functional group) have been found to be particularly effective.
Nonionic surfactants are added to further lower the surface tension of the composition and improve the high-temperature survivability of the flux to further reduce solder balling and bridging. The nonionic surfactant can resist decomposition on a boiling solder pot at a temperature of about 500xc2x0 F. (260xc2x0 C.). Suitable nonionic surfactants include, but are not limited to, nonylphenoxypolyethoxyethanols, Octylphenoxypolyethoxyethanols, alcohol ethoxylates, ethoxylated/propoxylated (EO-PO) copolymers, acetylinic diols, acetylinic diol ethoxylates, perfluoroalkyl ethylene oxides, perfluoroalkyl amine oxides and perfluoroalkyl carboxylates (e.g., S-141, S-145, S-111 and S-113, manufactured by Seimi Chemical Co., Japan).
While either the cationic or nonionic surfactant, by itself, can reduce the surface tension of the molten solder and metal surfaces to be joined, the combination of cationic and nonionic surfactants can produce unexpectedly positive results in terms of avoiding solder balling and solder bridging by dramatically lowering the surface tension of the molten solder and the surface energies of the metal surfaces to be joined, the solder mask on the PWB and the unmasked laminate. In particular, though the use of a nonionic surfactant can offer the desired high-temperature survivability, use of that nonionic surfactant, even at higher concentrations, is likely to still leave a substantial quantity of solder balls on the board surface. In contrast, a combined concentration of nonionic surfactant and cationic surfactant can produce a finished surface that is substantially free of solder balls and solder bridgesxe2x80x94substantially more so than if an equivalent concentration of either nonionic surfactant or cationic surfactant is used in the absence of the other.
The combination of the cationic and nonionic surfactants creates a synergistic effect by lowering both the surface tension of the molten solder and the surface energies of the metal surfaces to be joined, the solder mask on the PWB and the unmasked laminate. Consequently, the amounts of micro-solder balls, bridges and flux residues are reduced to very-low levels.
The flux composition may also comprise various high-boiling-point additives, such as alcohols, glycol ethers and esters to enable the flux to survive the heat of the soldering process in special high-temperature soldering applications. The alcohols may be of various types; for example, aromatic and/or long-chain aliphatic alcohols and rosin alcohols can all be used. Specific examples include benzyl alcohol, tetradecanol and/or hydroabeityl alcohol. Additionally, rosin esters, such as methyl or glycerol or pentaerythritol ester of rosin, esters of modified rosins or resins, such as methyl ester of hydrogenated rosin, and/or other types of esters, such as methyl esters of carboxylic acids, can be included in the flux. Various glycol ether solvents, such as dipropylene glycol monomethyl ether or ethylene/propylene glycol phenyl ether, can also be included in the flux. Rosins, resins and waxes that can be incorporated into the flux include gum rosin, tall oil rosin, wood rosins, chemically-modified resins and rosins (such as hydrogenated rosins), polymerized rosins, fumaric/maleic adducts of rosins, phenolic resins and other natural and synthetic resins, rosins and waxes. These rosins, resins and waxes can be used, alone or mixed together, to enhance electrical reliability of the soldered PWBs.
The flux composition also includes an activator system, which may comprise one or more organic carboxylic acids, such as succinic, adipic, itaconic, malonic, oxalic or glutaric acids. Alternatively, or in addition, the flux can include nonionic, covalent-bonded organic halide activators, particularly bromide activators, such as trans-2,3-dibromo-2-butene-1,4-diol (DBD), styrene dibromide or dibromosuccinic acid. Bromide activators can be mono-, di- or tri-bromo carboxylic acids. The activators chemically remove oxides from the surfaces to be soldered.
The flux can additionally comprise various property-enhancing ingredients in small amounts, which do not materially affect the flux""s basic fluxing properties. Such ingredients include, but are not limited to, corrosion inhibitors, dyes, foaming and/or defoaming agents, biocides and stabilizers. The use of such property-enhancing ingredients is well understood by those skilled in the art of flux formulating.
After the leads or terminations of a component are placed and positioned on a PCB (for example, by feeding the leads through plated or non-plated through-holes in the PCB), the flux can be applied to the leads and contacts by spray, foam, wave or other known methods. An air knife may then be used to remove excess flux, if necessary. After the flux is applied, the board is heated to volatilize the solvent; then the board typically is wave soldered by passing it over a molten solder wave. The wave soldering process deposits solder on the leads and contacts and the solder serves to bond and electrically connect the components to the board.
Flux compositions of the present invention can substantially ensure that the surface tension of the board and the molten solder is lowered during wave soldering so that solder does not form undesirable solder balls and/or bridges on the solder mask and in-between the component leads on the board. Furthermore, cleaning of residual flux from the PCB can be omitted such that the PCB can be used in an electronic application with tiny traces of flux residues remaining on the PCB.
Additional flux components and features, as well as additional methods involving the fluxes and methods described herein, are provided in L. Turbini, xe2x80x9cFluxes and Cleaning,xe2x80x9d Printed Circuits Handbook, 4th Ed., chapter 31 (1996), the teachings of which are incorporated herein by reference in their entirety.
Embodiments of the flux are further illustrated in the following example compositions. It should be understood, however, that although these descriptions particularly describe specific embodiments of the invention, the examples are primarily for purposes of illustration, and the invention, in its broader aspects, is not to be construed as limited thereto.


An electrical machine stator core and method for reducing electromagnetic losses and the consequent heating of the core. The stator core makes use of laminations made from an iron-aluminum alloy at the core-ends of the core, while laminations between the core-ends are formed of a ferromagnetic alloy different from the iron-aluminum alloy. Use of iron-aluminum alloy laminations at the core-ends makes possible a relatively simple technique for generator uprate, by removing laminations located at the core-ends of the stator core, and then installing replacement laminations formed of the iron-aluminum alloy at the core-end, again with the result that the laminations located at the core-ends are formed of an Fexe2x80x94Al alloy that is different from the alloy of the laminations between the core ends.

1. Field of the Invention
The present invention generally relates to dynamoelectric machines and stators therefor having cores formed of ferromagnetic laminations. More particularly, this invention relates to a stator core formed to include iron-aluminum alloy laminations in selected locations to reduce electromagnetic (core) losses.
2. Description of the Related Art
Generators, including large turbine-driven generators used in the production of electrical power, generally comprise a rotor coaxially supported within a bore formed by an annular-shaped stator. The rotor serves as a source of magnetic lines of flux that are produced by a wound coil carried on the rotor. The stator comprises a number of conductors in which voltage is induced by the rotor as the rotor rotates within the stator. The stator includes a stator core having slots that contain the conductors, or windings. The slots are located at the inner circumference of the core and extend in the axial direction, defining what may be termed teeth that project radially inward into the bore of the core. In addition to supporting the stator windings, the core must provide a low reluctance path for the lines of magnetic flux.
Stator cores for generators and other dynamoelectric machines are widely formed to have a laminate construction, in which a large number of laminations of a ferromagnetic material are axially stacked. Each lamination includes a layer of electrically insulating material to reduce eddy currents. Laminations are formed to have slots that must be aligned within the stack to define the winding slots of the core. Key bars may be employed at the outer circumference of the core to maintain the alignment of the laminations and the winding slots. Due to cost and material properties, iron-silicon (Fexe2x80x94Si) alloys have been the standard material for stator core laminations, particular for large turbine-driven generators. A typical Fexe2x80x94Si alloy for core laminations is a steel containing about 3 to about 3.5 weight percent silicon, with the balance being iron and low levels of carbon, manganese, etc. Alternative lamination alloys have been proposed, including an iron-aluminum alloy disclosed in U.S. Pat. No. 3,058,857 to Pavlovic et al., and an iron-silicon-aluminum alloy disclosed in U.S. Pat. No. 4,545,827 to Rastogi. The lamination alloy disclosed by Pavlovic et al. is said to contain about 1 to 10 weight percent aluminum, with the balance being essentially iron. Rastogi""s alloy is said to contain, by weight, 0.15 to 0.25 percent silicon, 0.15 to 0.25 percent aluminum, with the balance being iron, controlled levels of manganese, and incidental impurities. Industry practice is to use a single alloy for all laminations of a stator core.
Radial and peripheral magnetic flux components in the core and the axial magnetic flux component (normal to the plane of the stator core-end) induce eddy currents and cause electromagnetic (core) losses in the core laminations. The axial magnetic flux component causes heating and additional eddy current losses in the core-ends, which limit machine capability. Radial and peripheral flux components have been pushed to the limit by magnetic saturation, losses, and mechanical design considerations. Various approaches have been proposed to reduce losses caused by the axial flux component. One such approach is to increase the air-gap length between the stator and the rotor at the core-ends of the stator core. For example, core-end stepping is a commonly-used technique in which the laminations at the core-ends have increasingly larger inner diameters toward the end of the core. While effective, aggressive core-end stepping can reduce the clamping pressure on the teeth of the core. Reducing the relative axial length of the rotor with respect to the stator is another technique that has been employed to reduce the core-end fringing flux. However, the shorter length of the rotor increases the excitation requirement, contributing to lower efficiencies and potentially a bigger thermal challenge.
In view of the above, it would be desirable to reduce core losses and heating, especially in machine core-ends, without sacrificing reliability, efficiency, and performance of a dynamoelectric machine.
The present invention provides an electrical machine stator core and a method for reducing electromagnetic losses and the consequent heating of the core. The stator core makes use of laminations made from an iron-aluminum alloy in place of the standard iron-silicon (Fexe2x80x94Si) at the core-ends.
The stator core of this invention generally comprises a plurality of axially-aligned laminations, each of the laminations having an annular shape defining an outer circumference and an inner circumference. The stator core has oppositely-disposed core-ends and an intermediate portion therebetween. According to the invention, the laminations defining the core-ends are formed of an iron-aluminum alloy, and at least one of the laminations defining the intermediate portion is formed of a ferromagnetic alloy different from the iron-aluminum alloy. According to the invention, placement of the iron-aluminum alloy laminations at the core-ends offers the capability of reducing the electromagnetic losses and consequent heating of the cores, and provides additional potential benefits including improved thermal, electrical, magnetic and mechanical properties, the latter of which includes better ductility for improved machine reliability.
Use of iron-aluminum alloy laminations at the core-ends makes possible a relatively simple technique for generator uprate, by which a partial re-stacking of the core-ends can be an effective solution to reduce core-end losses and temperatures. Retrofitting a stator core in this manner generally comprises removing the laminations located at one or both of the core-ends of the stator core, and then installing replacement iron-aluminum alloy laminations at the core-end, with the result that the laminations located at the core-end are formed of an alloy that is different from the alloy of the laminations remaining at the intermediate portion of the stator core.
A significant advantage of this invention is the ability to reduce core losses and heating of a dynamoelectric machine, especially at the machine core-ends, without sacrificing reliability, efficiency, and performance. A particularly notable advantage is the ability to uprate an existing dynamoelectric machine by partially re-stacking the core-end laminations without necessitating the removal and replacement of all laminations of the stator core. The present invention also makes possible the optimization of a new machine by the selective installation of iron-aluminum alloy laminations at the core-ends.
Other objects and advantages of this invention will be better appreciated from the following detailed description.

Stator core containing iron-aluminum alloy laminations and method of using