Abstract: A combination vacuum gauge provides simultaneous absolute and differential pressure measurements over a wide range of pressures ranging from atmospheric pressures to ultrahigh vacuum by processing the readings from an absolute high vacuum gauge (e.g., an ionization gauge and/or a heat-loss sensor), a differential low vacuum gauge providing a differential relative to ambient pressure (e.g., a diaphragm sensor), and a barometric absolute pressure sensor exposed to the ambient atmosphere outside the measurement region. The barometric absolute pressure sensor reading is used to convert the differential vacuum gauge reading from uncalibrated differential pressure to calibrated absolute pressure.

Abstract: A method and apparatus for measuring gas pressure by combining an ionization gauge with at least one other vacuum sensor. Nonvolatile memory coupled to the vacuum gauge contains calibration parameters unique to each individual sensor based on factory calibration. The nonvolatile memory may contain calibration parameters for a heat-sensitive vacuum sensor to compensate for the temperature gradients generated by the ionization gauge. The calibration parameters are a function of calibration data determined when the ionization gauge is both on and off. The nonvolatile memory may store a window of measurement data of the vacuum gauge that is updated at predetermined time intervals and in response to an event, such as an error event, to aid in investigating the cause of vacuum gauge malfunction or failure.

Abstract: Refrigerant freezeout is prevented by the use of a controlled bypass flow that causes a warming of the lowest temperature refrigerant in a refrigeration system that achieves very low temperatures by using a mixture of refrigerants comprising at least two refrigerants with boiling points that differ by at least 50° C. This control capability enables reliable operation of the very low temperature system.

Abstract: A piston includes a circumferential groove having a dynamic split seal ring having a flat axially facing surface, a static seal ring having a flat axially facing surface abutting the flat surface of the dynamic seal ring, and a spring mounted within the groove. The spring exerts an axial force on the static seal ring that serves to distribute the axial load with a static seal over the dynamic split seal, thereby preventing shuttling of the split seal within the groove and restricting the leak path of the seal. Preferably, the static seal ring is a polymer and can be an L-ring, a load ring with a flange that abuts the piston body, or flanged designs. In addition, a load ring can be fitted between the L-ring and the spring. The split seal ring has at least one radial spring mounted within the seal ring to create a radial force on the split seal ring. The piston can also include a sleeve that mounts to the piston body, the sleeve forming a wall of the groove.

Abstract: A cryopump provides for high pumping speed of Type III gases. An open configuration of a frontal array provides high conductance of gases into a radiation shield which is shaped to focus gases toward a second stage array. The second stage array has an open configuration of baffles coated with adsorbent. Substantially all of the adsorbent has a direct line of sight to the radiation shield or to the opening in the radiation shield, and substantially all of the baffles are coated with adsorbent. In one form, the second stage cryopump array comprises an array of discs fanned to define a generally ball shaped envelope.

Abstract: Status information about the vacuum system is received by a server. A portion of the status information is formatted in response to a request from a web browser, and the formatted vacuum system information is forwarded to the web browser. Commands, including parameter values, can are entered by a user from the web browser, and implemented at the server or forwarded to the proper component in the vacuum system. A command or change history log of commands is maintained and forwarded to the web browser upon a request from the web browser. Status information includes information about an on-going regeneration of a pump in the vacuum system. Furthermore, regeneration can be controlled, i.e., started, stopped, parameters adjusted, in response to commands received from the web browser. Plural sets of regeneration parameters can be defined by a user from the web browser, and issued simultaneously to many devices.

Abstract: In a resistively heated heat-loss pressure gauge, electrical current is switched between a sensing element and a compensating element at different duty cycles. As a result, the sensing element is heated relative to the compensating element. A fixed resistance is placed in series with at least the compensating element. The current source applies current to heat the sensing element to a temperature at which the resistance of the sensing element matches the combined resistance of the compensating element and the fixed resistive element.

Abstract: In a resistively heated heat-loss pressure gauge, electrical current is switched between a sensing element and a compensating element at different duty cycles. As a result, the sensing element is heated relative to the compensating element. A fixed resistance is placed in series with at least the compensating element. The current source applies current to heat the sensing element to a temperature at which the resistance of the sensing element matches the combined resistance of the compensating element and the fixed resistive element.

Abstract: A system and method is provided to control a purge valve during an unsafe condition associated with a cryopump. An electronic controller may be used to control the opening and closing of one or more purge valves during the unsafe condition. The purge valve can be a cryo-purge valve or exhaust purge valve. The purge valve can be a normally open valve. The electronic controller can release the normally open valve in response to the unsafe condition. The electronic controller can delay its response to the unsafe condition for a safe period of time. Attempts from other systems to control these valves during unsafe conditions can be preempted during unsafe conditions. A user can be inhibited from manually controlling the purge valve during unsafe conditions. A power failure recovery routine may be initiated in response to a restoration of power. The power failure recovery routine can respond to an unsafe condition even if the power failure recovery routine has been manually turned off by a user.

Abstract: A single ducted valve assembly provides an integrated cryopump valve having a purge valve port connecting the assembly to a cryopump with a coaxial connection having an inner duct and an outer duct. A pressurized gas interface connects a pressurized gas source to the cryopump through the inner duct. A rough valve port can connect the outer duct of the assembly to a rough vacuum pump; and a relief valve port can connect the outer duct of the assembly to an exhaust stack.

Abstract: A heat loss gauge for measuring gas pressure in an environment includes a resistive sensing element and a resistive compensating element. The resistive compensating element is in circuit with the sensing element and is exposed to a substantially matching environment. An electrical source is connected to the sensing element and the compensating element for applying current through the elements. The current through the sensing element is substantially greater than the current through the compensating element. Measuring circuitry is connected to the sensing element and the compensating element for determining gas pressure in the environment to which the sensing element and compensating element are exposed based on electrical response of the sensing element and the compensating element.

Abstract: A vacuum system comprises, as an integral assembly, a vacuum pump with drive motor, a purge valve, a roughing valve and an electronic control module. A cryogenic vacuum pump and a turbomolecular vacuum pump are disclosed. The control module has a programmed processor for controlling the motor and valves and is user programmable for establishing specific control sequences. The integral electronic control module is removable from the assembly and is connected to the other devices through a common connector assembly. In the turbomolecular pump system proper introduction of a purge gas through the purge valve is detected by detecting the current load on the pump drive or by detecting foreline pressure. To test the purge gas status, the purge valve may be closed and then opened as drive current or pressure is monitored. After power failure, the controller will continue normal drive of the turbomolecular pump so long as the speed of the pump has remained above a threshold value.

Abstract: A heat loss gauge for measuring gas pressure in an environment includes a resistive sensing element and a resistive compensating element. The resistive compensating element is in circuit with the sensing element and is exposed to a substantially matching environment. An electrical source is connected to the sensing element and the compensating element for applying current through the elements. The current through the sensing element is substantially greater than the current through the compensating element. Measuring circuitry is connected to the sensing element and the compensating element for determining gas pressure in the environment to which the sensing element and compensating element are exposed based on electrical response of the sensing element and the compensating element.

Abstract: An ionization gauge for isolating an electron source from gas molecules includes the electron source for generating electrons, a collector electrode for collecting ions formed by the impact between the electrons and gas molecules, and an electron window which isolates the electron source from the gas molecules. The ionization gauge can have an anode which defines an anode volume and retains the electrons in a region of the anode. The ionization gauge can have a plurality of electron sources and/or collector electrodes. The collector electrode(s) can be located within the anode volume or outside the anode volume. The ionization gauge can have a mass filter for separating the ions based on mass-to-charge ratio. The ionization gauge can be a Bayard-Alpert type that measures pressure or a residual gas analyzer that determines a gas type.

Abstract: An electronic controller is integral with a cryopump and provides an offline solution for purging a cryopump and an exhaust line during unsafe conditions. The electronic controller is responsible for controlling the opening and closing of purge, exhaust purge and gate valves coupled to the cryopump. The electronic controller can preempt any attempts from other systems to control these valves during unsafe conditions. An unsafe condition can be a power failure in the cryopump, a dangerous temperature in the cryopump or a temperature sensing diode that is not operating properly. When an unsafe condition is determined, the exhaust purge valve is opened and the gate valve closed, while the opening of a purge valve may be delayed for a safe period of time. If the unsafe condition still exists when the safe period of time elapses, the purge valve is allowed to open. A fail-safe purge valve release and time delay mechanism can be used to ensure that the purge valve opens after the period of time elapses.

Abstract: A piston includes a circumferential groove having a dynamic split seal ring having a flat axially facing surface, a static seal ring having a flat axially facing surface abutting the flat surface of the dynamic seal ring, and a spring mounted within the groove. The spring exerts an axial force on the static seal ring that serves to distribute the axial load with a static seal over the dynamic split seal, thereby preventing shuttling of the split seal within the groove and restricting the leak path of the seal. Preferably, the static seal ring is a polymer and can be an L-ring, a load ring with a flange that abuts the piston body, or flanged designs. In addition, a load ring can be fitted between the L-ring and the spring. The split seal ring has at least one radial spring mounted within the seal ring to create a radial force on the split seal ring. The piston can also include a sleeve that mounts to the piston body, the sleeve forming a wall of the groove.

Abstract: A vacuum system comprises, as an integral assembly, a vacuum pump with drive motor, a purge valve, a roughing valve and an electronic control module. A cryogenic vacuum pump and a turbomolecular vacuum pump are disclosed. The control module has a programmed processor for controlling the motor and valves and is user programmable for establishing specific control sequences. The integral electronic control module is removable from the assembly and is connected to the other devices through a common connector assembly. In the turbomolecular pump system proper introduction of a purge gas through the purge valve is detected by detecting the current load on the pump drive or by detecting foreline pressure. To test the purge gas status, the purge valve may be closed and then opened as drive current or pressure is monitored. After power failure, the controller will continue normal drive of the turbomolecular pump so long as the speed of the pump has remained above a threshold value.

Abstract: An electronic controller is integral with a cryopump and provides an offline solution for purging a cryopump and an exhaust line during unsafe conditions. The electronic controller is responsible for controlling the opening and closing of purge, exhaust purge and gate valves coupled to the cryopump. The electronic controller can preempt any attempts from other systems to control these valves during unsafe conditions. An unsafe condition can be a power failure in the cryopump, a dangerous temperature in the cryopump or a temperature sensing diode that is not operating properly. When an unsafe condition is determined, the exhaust purge valve is opened and the gate valve closed, while the opening of a purge valve may be delayed for a safe period of time. If the unsafe condition still exists when the safe period of time elapses, the purge valve is allowed to open. A fail-safe purge valve release and time delay mechanism can be used to ensure that the purge valve opens after the period of time elapses.

Abstract: An electronic controller maintains the operating temperature of a cryopump by controlling a heater coupled to the cryopump. The heater is coupled to a cryopumping surface of the cryopump. The controller can control the operation of the heater in response to feedback from temperature sensors coupled to the cryopump. The controller can cause the heater to shut-off if a temperature sensor reads out of its normal temperature range.

Abstract: A securing mechanism includes a connector latch and a module latch such that engagement of the connector latch with a connector causes the module latch to engage a housing support. The securing mechanism prevents removal of a module from a housing support when a connector, such as on a power cable, is engaged by the connector latch. The connector latch has a position adjustment mechanism, engageable by an external tool, that controls the position of the connector latch. A tool is used to position the connector latch and allow the insertion or removal of the connector.