Abstract: In situations where a vacuum system is suddenly overloaded, there is a risk of mechanical damage being sustained, for example, bearing damage, gear slippage or rotor and/or stator collisions. Sudden overloads can also lead to electrical damage, for example, over-currents or power surges. Therefore a pressure regulating apparatus is provided for use in a vacuum pumping system having an inlet, an outlet and a conduit interposed between, and in fluid communication with, the inlet and the outlet, wherein the cross-sectional area of the conduit is greater than that required to meet the conductance requirements of the inlet and the outlet.

Abstract: An image tile server importantly includes an image tile cache, to support a tiled map display in a user device. Instead of the conventional user device client (e.g., an Ajax client) making image requests directly to a mapping server (MS), a display device initiates an image request of a tile server (TS), and the tile server returns the requested image. However, importantly, the tile server (TS) also retains a cached copy of the returned image for faster retrieval at a later time relating to another image request by the same or different user device.

Abstract: An image tile server importantly includes an image tile cache, to support a tiled map display in a user device. Instead of the conventional user device client (e.g., an Ajax client) making image requests directly to a mapping server (MS), a display device initiates an image request of a tile server (TS), and the tile server returns the requested image. However, importantly, the tile server (TS) also retains a cached copy of the returned image for faster retrieval at a later time relating to another image request by the same or different user device.

Abstract: A method for adjusting operating parameters of a vacuum pump arrangement includes determining characteristics of a gas flowing through the vacuum pump arrangement; and setting operating parameters of the vacuum pump arrangement based on the determined characteristics of the first gas. A controller can be configured to perform the method for adjusting the operating parameters of the vacuum pump arrangement in accordance with the characteristics of the gas.

Abstract: A pair of Northey rotors for a vacuum pump, in which each rotor comprises two opposing, substantially parallel faces, and a peripheral surface located between the opposing faces. In order to reduce damage caused by pumping a gas stream containing liquid or solid particulates, a plurality of grooves is located on the peripheral surface for accommodating the particulates.

Abstract: The present invention relates to a multi-stage vacuum pump which has a plurality of pumping stages. The pump comprises a stator forming the pumping chambers of respective pumping stages and at least one shaft, for supporting a plurality of rotors for rotation in respective pumping chambers. The stator comprises: a stator envelope which extends over an axial extent of a plurality of stator stages thereby circumscribing said at least one shaft and forming an internal profile of a plurality of stator stages: and a plurality of transverse walls located on either axial side of the stator stages to form respective said pumping chambers. At least one of the transverse walls is an inter-stage between stator stages and the stator envelope is configured to circumscribe the inter-stage for location of said inter-stage radially inward of the stator part.

Abstract: A screw pump includes a stator having a fluid inlet and a fluid outlet, the stator housing first and second externally threaded, tapered rotors mounted on respective shafts and adapted for counter-rotation within the stator to compress fluid passing from the fluid inlet to the fluid outlet, wherein the threads have a pitch that increases towards the fluid outlet.

Abstract: A multi-stage vacuum pump may include first and second half-shell components defining a plurality of pumping chambers and for assembly together along respective longitudinal extending faces; first and second end stator components for assembly at respective longitudinal seals for sealing between the first and second half-shell stator components when assembled together at the longitudinally extending faces; and annular seals for sealing between the first and second end stator components and the first and second half-shell stator components when assembled; wherein the longitudinal seals have end portions which abut against the annular seals for sealing therebetween and the first and second half-shell stator components have formations for resisting movement of the end portions away from the annular seals when the end portions are compressed between the first and second half-shell stator components.

Abstract: This disclosure describes systems and associated methods that can selectively filter seed behavior, e.g., user activity used to generate item recommendations. In some embodiments, seed behaviors and catalog items are associated with categories in an electronic catalog, and a particular seed behavior is used to generate user recommendations if it is more recent than a user's last purchase in the category of the seed behavior. For example, a user's activity in the TV category, e.g., viewing various TV models, may not be used to generate recommendations if the activity occurred prior to the user's purchase of a TV. As a result, in certain embodiments, additional TVs may not appear in the user's recommendations following her purchase, reflecting that the user has fulfilled her desire to purchase a TV.

Abstract: This disclosure describes systems and associated methods that can selectively filter seed behavior, e.g., user activity used to generate item recommendations. In some embodiments, seed behaviors and catalog items are associated with categories in an electronic catalog, and a particular seed behavior is used to generate user recommendations if it is more recent than a user's last purchase in the category of the seed behavior. For example, a user's activity in the TV category, e.g., viewing various TV models, may not be used to generate recommendations if the activity occurred prior to the user's purchase of a TV. As a result, in certain embodiments, additional TVs may not appear in the user's recommendations following her purchase, reflecting that the user has fulfilled her desire to purchase a TV.

Abstract: This disclosure describes systems and associated methods that can selectively filter seed behavior, e.g., user activity used to generate item recommendations. In some embodiments, seed behaviors and catalog items are associated with categories in an electronic catalog, and a particular seed behavior is used to generate user recommendations if it is more recent than a user's last purchase in the category of the seed behavior. For example, a user's activity in the TV category, e.g., viewing various TV models, may not be used to generate recommendations if the activity occurred prior to the user's purchase of a TV. As a result, in certain embodiments, additional TVs may not appear in the user's recommendations following her purchase, reflecting that the user has fulfilled her desire to purchase a TV.

Abstract: An image tile server importantly includes an image tile cache, to support a tiled map display in a user device. Instead of the conventional user device client (e.g., an Ajax client) making image requests directly to a mapping server (MS), a display device initiates an image request of a tile server (TS), and the tile server returns the requested image. However, importantly, the tile server (TS) also retains a cached copy of the returned image for faster retrieval at a later time relating to another image request by the same or different user device.

Abstract: An image tile server importantly includes an image tile cache, to support a tiled map display in a user device. Instead of the conventional user device client (e.g., an Ajax client) making image requests directly to a mapping server (MS), a display device initiates an image request of a tile server (TS), and the tile server returns the requested image. However, importantly, the tile server (TS) also retains a cached copy of the returned image for faster retrieval at a later time relating to another image request by the same or different user device.

Abstract: A screw pump (10) comprises a stator (12) having a fluid inlet (18) and a fluid outlet (20), the stator housing first and second externally threaded, tapered rotors (26, 28) mounted on respective shafts and adapted for counter-rotation within the stator (12) to compress fluid passing from the fluid inlet to the fluid outlet, wherein the threads (30, 32) have a pitch that increases towards the fluid outlet (20).

Abstract: A pair of Northey rotors for a vacuum pump, in which each rotor comprises two opposing, substantially parallel faces, and a peripheral surface located between the opposing faces. In order to reduce damage caused by pumping a gas stream containing liquid or solid particulates, a plurality of grooves is located on the peripheral surface for accommodating the particulates.

Abstract: An image tile server importantly includes an image tile cache, to support a tiled map display in a user device. Instead of the conventional user device client (e.g., an Ajax client) making image requests directly to a mapping server (MS), a display device initiates an image request of a tile server (TS), and the tile server returns the requested image. However, importantly, the tile server (TS) also retains a cached copy of the returned image for faster retrieval at a later time relating to another image request by the same or different user device.

Abstract: A seal assembly for the protection of a static seal device for use in a vacuum pump. The seal assembly comprising at least two components which are sealingly connected together, an o-ring seal, which is engaged between the two components to prevent transfer of fluid to and from the pump between these two components and a fluid channel. The fluid channel being in the plane of the o-ring and located between the o-ring seal and a process gas flow path. The fluid channel provides a path for a barrier gas to be routed when the apparatus is in use. The channel being connectable to an external source of barrier fluid and having an outlet in fluid communication with the pump swept volume.

Abstract: A seal assembly for the protection of a static seal device for use in a vacuum pump. The seal assembly comprising at least two components which are sealingly connected together, an o-ring seal, which is engaged between the two components to prevent transfer of fluid to and from the pump between these two components and a fluid channel. The fluid channel being in the plane of the o-ring and located between the o-ring seal and a process gas flow path. The fluid channel provides a path for a barrier gas to be routed when the apparatus is in use. The channel being connectable to an external source of barrier fluid and having an outlet in fluid communication with the pump swept volume.

Abstract: A vacuum pump system (10; 36; 46) for pumping gas from an enclosure (12) comprises: a vacuum pump unit (14) having a pump inlet (16) connectable with an outlet (18) of such an enclosure and a pump outlet (20) for exhausting gas; and a chamber (22; 50) selectively connectable with the pump inlet and the pump outlet, such that, in use, in a first state gas can be pumped from the chamber to the pump inlet by the vacuum pump unit and in a second state gas can be evacuated from the pump outlet to the chamber to reduce pressure at the pump outlet. A method of controlling the vacuum pump system (10; 36; 46) comprises a first step of pumping gas from the chamber to the pump inlet using the vacuum pump unit and a second step of allowing gas to be evacuated from the pump outlet to the chamber to reduce pressure at the pump outlet.

Abstract: This invention relates to a cellular communication system (200), billing processor (223) and method of billing. The communication system includes a subscriber unit (201) having a user updateable identity to phone number association table used for dialling phone numbers based on an identity such as a name. It also includes means (203, 205,219,217) for communicating the table to a billing processor (223) being part of the fixed network. The billing processor (223) comprises means (227) for receiving the table and generating a billing association table containing information from the identity to phone number association table. It furthermore comprises a billing report generator (225) for generating a billing report for the subscriber unit (201) including identity information derived from the billing association table. The invention is applicable to cellular communication systems such as UMTS.