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: 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: 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 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 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 cryopump having a cryopump chamber includes a purge gas valve coupled to the cryopump chamber for supplying a first quantity of warm gas to the cryopump chamber in order to purge the cryopump chamber during regeneration. A roughing valve couples the cryopump chamber to a roughing pump enabling the cryopump chamber to be roughed. An exhaust valve is coupled to the cryopump chamber for exhausting gases from the cryopump chamber during purge. A delivery valve is coupled to the exhaust valve for delivering a second quantity of warm gas directly onto surfaces of the exhaust valve for warming the surfaces of the exhaust valve.

Abstract: The cryopanel of a cryopump can be preferentially defrosted to remove an acid-forming or toxic gas while leaving a second gas substantially condensed upon the cryopanel thereby limiting interaction between the vapor phases of the two gases. The cryopanel is warmed to a temperature within a selective defrost range at which the first gas selectively sublimates from the cryopanel. The temperature of the cryopanel is then maintained at a temperature within this range until the cryopanel is substantially cleared of the first gas leaving the second gas substantially undisturbed as a condensate upon the cryopanel. In a preferred embodiment, the cryopanel is maintained at about 50 to 85K during standard operation before being defrosted.

Abstract: A method for regulating the cooldown of multiple cryogenic refrigerators supplied with compressed refrigerant from a common compressor includes the following steps. The cooldown of the refrigerators is monitored. The cooldown of at least one refrigerator is then governed to regulate the gas flow distributed from the compressor to each of the refrigerators to enhance the cooldown of an individual refrigerator. Governing a refrigerator to achieve the objectives of this method can be achieved by various processes. These processes include supplying heat to the refrigerator, slowing the speed of the displacer in the refrigerator, halting the motion of the displacer, and profiling the speed of the displacer as a function of the first and second-stage temperatures.

Abstract: In a subatmospheric regeneration process, a relief valve and a roughing valve are coupled in parallel to a common roughing pump. During regeneration, the cryopump is warmed to release gases from cryopump stages. The relief valve opens at a first cryopump pressure level less than a predetermined maximum pressure. The maximum pressure is subatmospheric. The relief valve closes when the cryopump pressure drops below a second cryopump pressure level. Pressure in a line between the relief valve and the roughing pump is monitored to control the opening of the roughing valve to the roughing pump.

Abstract: A cryogenic vacuum pump includes, in an integral assembly, temperature sensors and heaters associated with the first and second stages of the cryopumping array, a roughing valve and a purge valve. An electronic module removably coupled in the assembly responds to all sensors and controls all operations of the cryopump including regeneration thereof. System parameters are stored in a nonvolatile memory in the module. Included in the regeneration procedures are an auto-zero of the pressure gauge, heating of the array throughout rough pumping, and a change in pressure rate test to determine stall in rough pumping. The electronic module also restarts the system after power failure, limits use of a pressure gauge to safe conditions, provides warnings before allowing opening of the valves while the cryopump is operating and stores sensor calibration information. Control through a control pad on the pump may be limited by a password requirement. Password override is also provided.

Abstract: A cryogenic vacuum pump includes, in an integral assembly, temperature sensors and heaters associated with the first and second stages of the cryopumping array, a roughing valve and a purge valve. An electronic module removably coupled in the assembly responds to all sensors and controls all operations of the cryopump including regeneration thereof. System parameters are stored in a nonvolatile memory in the module. Included in the regeneration procedures are an auto-zero of the pressure gauge, heating of the array throughout rough pumping, and a change in pressure rate test to determine stall in rough pumping. The electronic module also restarts the system after power failure, limits use of a pressure gauge to safe conditions, provides warnings before allowing opening of the valves while the cryopump is operating and stores sensor calibration information. Control through a control pad on the pump may be limited by a password requirement. Password override is also provided.

Abstract: An exhaust port from a cryopump vacuum vessel leads to an exhaust valve. The valve is protected from contamination by a filter standpipe which extends from the exhaust port into the vacuum vessel and which is open at its end opposite to the exhaust port. The standpipe is of porous material which allows the free flow of gas, water, and liquid cryogens therethrough while retaining contaminating debris within the vacuum vessel. The filter conduit is of screen formed into a cylinder. One end is tapered and pressed into the exhaust conduit. The screen cylinder is stopped in the exhaust conduit by a circumferential ridge.

Abstract: An oil free vacuum system 10 which comprises a high thermal capacitance cryopump 12 and air ejector 38. The air ejector 38 is used to reduce load lock chamber 16 pressure to an intermediate vacuum. Cryopump 12 further evacuates chamber 12 to the operating vacuum of a work chamber 14. The work chamber 14 is maintained at high vacuum by a main cryopump 20. The main cryopump can be started in an oil free manner through the use of air ejector 38 and high thermal capacitance cryopump 12. A high themal capacitance, high thermal conductance cryopanel is formed of a lead/copper sandwich.

Abstract: In a cryopump, condensation of gases such as argon, oxygen and nitrogen on surfaces other than the second stage array 38, 40 is avoided to prevent cross over hang up and pressure instability. To prevent condensation of argon, oxygen and nitrogen on the frontal cryopumping array 46, that array is held to a temperature of at least 50.degree. K. A heat load to the first stage increases as the temperature of the first stage drops. That heat load is provided by a high emissivity radiation shield 44 or by a thermal switch 56, 58. Condensation of argon and other gases on the second stage refrigerator cylinder 32 is avoided by a close fitting sleeve 52 positioned over the refrigerator cylinder 32 in thermal contact with the second stage heat sink 30 but out of thermal contact with the cylinder 32.