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 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.

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.

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.

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 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 electronic controller is used to control a vacuum gauge in a vacuum system. The electronic controller may be coupled to a vacuum pump in the vacuum system. Preferably, the vacuum pump is a cryopump. The electronic controller determines whether there is a potentially dangerous condition present in the vacuum system. A potentially dangerous condition may be present, for example, if there is a sufficient amount of gas in the vacuum pump to ignite. If the vacuum pump is filed with inert gas, such as nitrogen, then the potentially dangerous condition is not present. The potentially dangerous condition is present when the temperature of the vacuum pump is above a temperature setpoint, such as 20K. The electronic controller responds to a potentially dangerous condition by preventing the vacuum gauge from being turned on.

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 has temperature response and physical characteristics substantially matching those of the resistive sensing element and is exposed to a substantially matching environment. An electrical source is connected to the sensing element for applying current to heat the sensing element relative to 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 conduit connected to a vacuum pump has a shield surface which absorbs radiation to reduce the total radiation falling on the vacuum pump. The vacuum system includes the vacuum conduit connected between a process chamber and the vacuum pump and a surface treatment along at least a portion of the shield surface adapted to absorb radiation. Since the treatment is on the interior surface of the vacuum conduit and does not extend into the center of the conduit, gaseous flow to the pump is not impeded. In this manner radiation entering the vacuum pump and falling on the cryogenic array is reduced without impeding gaseous flow to the cryogenic surface. The system therefore minimizes the radiation load on the cryogenic array in the vacuum pump without impeding the gaseous flow through the vacuum pump.

Abstract: In a cryogenic vacuum pump, after determining that a power fail recovery mode is on, and that the temperature is below a setpoint, the cryopump is automatically cooled. If the power fail recovery mode is on, and the temperature is above the setpoint, a regeneration cycle is started automatically. If the power fail recovery mode is off, the cryopump may be maintained in an off state. When a command to turn on a pressure sensing thermocouple (TC) gauge is received, the TC gauge is turned on only if there is not a sufficient amount of gas to ignite. When a command to turn on a roughing valve is received, an additional command must be received before the roughing valve is turned on. When a temperature-sensing diode is faulty, temperature control is automatically turned off. During a regeneration cycle, a purge test is performed. If the purge test passes, heaters are turned on. If the purge test fails, the heaters are turned on only if the temperature reaches a threshold within a predetermined period.

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 has temperature response and physical characteristics substantially matching those of the resistive sensing element and is exposed to a substantially matching environment. An electrical source is connected to the sensing element for applying current to heat the sensing element relative to 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 network control system includes a vacuum network controller hub communicating over a public high-speed network, where the hub has an address registered with respect to the non-local network and communicates over a first local high-speed network. Vacuum network controllers (VNCs) communicate with the hub over the first local network. Each VNC has a dynamically assigned local address and communicates with at least one component intrabus module over a second local high-speed network. Each module has a dynamically assigned local address and further communicates with one or more monitor and control end units over a local device network. Each monitor and control end unit has a dynamically assigned address. Monitor and control end units include taps, which provide at least one of analog, digital or serial I/O, and components, for example, vacuum pumps.

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 has temperature response and physical characteristics substantially matching those of the resistive sensing element and is exposed to a substantially matching environment. An electrical source is connected to the sensing element for applying current to heat the sensing element relative to 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 piston includes a circumferential groove having a seal ring and spring mounted within the groove. The spring exerts an axial force on the seal ring thereby preventing motion of the seal ring within the groove. Preferably, the spring in a wave spring, wherein small changes in deflection of the wave spring produces small changes in the load generated by the spring on the seal ring. The seal ring has at least one radial spring ring mounted within the seal ring to create a radial force on the seal ring. The piston can also include a sleeve that mounts to the piston body, the sleeve forming a wall of the groove. The piston can be a displacer mounted within a cylinder of a refrigerator.

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 pressure transducer assembly includes a transducer member supporting a transducer element for measuring pressure within an environment. The transducer member has a sealing surface surrounding the transducer element. A housing having an integral resilient member resiliently supports the transducer member and exerts a sealing force on the transducer member against a mating member secured to the housing.

Abstract: In a cryogenic vacuum pump, after determining that a power fail recovery mode is on, and that the temperature is below a setpoint, the cryopump is automatically cooled. If the power fail recovery mode is on, and the temperature is above the setpoint, a regeneration cycle is started automatically. If the power fail recovery mode is off, the cryopump may be maintained in an off state. When a command to turn on a pressure sensing thermocouple (TC) gauge is received, the TC gauge is turned on only if there is not a sufficient amount of gas to ignite. When a command to turn on a roughing valve is received, an additional command must be received before the roughing valve is turned on. When a temperature-sensing diode is faulty, temperature control is automatically turned off. During a regeneration cycle, a purge test is performed. If the purge test passes, heaters are turned on. If the purge test fails, the heaters are turned on only if the temperature reaches a threshold within a predetermined period.

Abstract: An apparatus and method are provided for controlling a system pressure in a refrigeration system based on a variable load, which includes sensing return pressure and high side pressure in the system, and adjusting the low pressure to optimize a gas flow rate in the system by adding or removing gas from the system through an operating range of pressures in response to the sensed return pressure and the sensed high side pressure. The method further includes calculating a pressure difference between the return pressure and the high side pressure. A second pressure difference is calculated, and if the pressure difference decreases, gas is added to system and if the pressure difference increases, gas is removed from the system.

Abstract: In a power failure recovery, the operating state before a power failure and present conditions of a cryopump are determined to initiate a regeneration or startup process. Where the refrigerator was operating before power failure, it is turned on during recovery to condense gases in the cryopump. A startup process is initiated where the cryopump was in a startup process before the power failure and present conditions of the cryopump indicate that the cryopump is sufficiently empty or clean. If the operating state and present conditions indicate that a corrosive or hazardous liquid remains in the cryopump, a regeneration process is initiated. If the cryopump was in a shutdown process before the power failure, the cryopanel of the cryopump is refrigerated to a temperature at which gases sublimate from the cryopanel. The temperature of the cryopanel is then maintained until the gases are removed.

Abstract: A helium management control system for controlling the helium refrigerant supply from a common manifold supplies a plurality of cryogenic refrigerators with an appropriate helium supply. The system employs a plurality of sensors to monitor and regulate the overall refrigerant supply to deliver an appropriate refrigerant supply to each of the cryogenic refrigerators depending on the computed aggregate cooling demand of all of the cryogenic refrigerators. An appropriate supply of helium is distributed to each cryopump by sensing excess and sparse helium refrigerant and redistributing refrigerant accordingly. If the total refrigeration supply exceeds the total refrigerant demand, or consumption, excess refrigerant is directed to cryogenic refrigerators which can utilize the excess helium to complete a current cooling function more quickly.