Cryopump

A cryopump comprising:

• a compressor unit for inhaling a low pressure working gas and discharging a high pressure and ordinary temperature working gas;
• an expanding portion driven by an expander motor for adiabatically expanding said high pressure and ordinary temperature working gas discharged from said compressor unit to generate a cryogenic temperature, said compressor unit and said expanding portion being connected to each other to form a closed circuit;
• and
• a cryopanel cooled by the cryogenic temperature generated by said expanding portion,
• characterized in that said cryopump further comprises:
• detecting means for detecting an operation parameter at an elapsed operation time in a current operation cycle of said cryopump;
• storing means for storing a value of a diagnosis parameter for judging a time for maintenance or regeneration of said cryopump;
• arithmetic controlling means for judging whether said cryopump is now in the time for maintenance or regeneration by comparing the current operation parameter detected by said detecting means with the value of the diagnosis parameter stored in said storing means and outputting an alarm signal;
• and
• controlling means for displaying that the cryopump is now in the time for maintenance or regeneration based on the alarm signal output from said arithmetic controlling means.

A cryopump comprising:

• a compressor unit for inhaling a low pressure working gas and discharging a high pressure and ordinary temperature working gas;
• an expanding portion driven by an expander motor for adiabatically expanding the high pressure and ordinary temperature working gas discharged from said compressor unit to generate a cryogenic temperature, said compressor unit and said expanding portion being connected to each other to form a closed circuit;
• and
• a cryopanel cooled by the cryogenic temperature generated by said expanding portion,
• characterized in that said cryopump further comprises:.
• detecting means for detecting an operation parameter at an elapsed operation time in a current operation cycle of said cryopump;
• storing means for storing a value of another operation parameter at a corresponding elapsed operation time in a past operation cycle of said cryopump as a management parameter and storing a value of a diagnosis parameter to judge a time for maintenance or regeneration of said cryopump;
• arithmetic controlling means for calculating a succeeding rotational speed of said expander motor based on the current operational parameter and the management parameter stored in said storing means and outputting the same as a driving instruction signal, with which a succeeding rotational speed of said expander motor is controlled so as to maintain a temperature of the cryopanel or a pressure in a chamber to which the cryopump is attached at a predetermined value by using a current rotational speed of said expander motor and a preceding rotational speed at the corresponding elapsed operation time in the past operation cycle of said cryopump stored in said storing means as the management parameter, and for judging whether said cryopump is now in the maintenance time or the regeneration time by comparing the current operation parameter detected by said detecting means with the value of the diagnosis parameter stored in said storing means and outputting an alarm signal;
• expander motor driving means for driving said expander motor according to the driving instruction signal output from said arithmetic controlling means;
• and
• controlling means for displaying that the cryopump is now in the maintenance time or the regeneration time based on the alarm signal output from said arithmetic controlling means.

A regenerative apparatus for a cryopump which includes at least one of first and second stage cryopanel surfaces to at least one of condense and absorb gases thereon during a pump operation and a cooling mechanism for cooling said cryopanel surfaces, said regenerative apparatus comprising:

• heating means for heating at least one of said first stage cryopanel surface and said second stage cryopanel surface,
• a temperature sensor for detecting a temperature of said cryopanel surfaces,
• pressure detecting means for detecting an internal pressure of said cryopump,
• control means for generating a control signal in response to an output from said temperature sensor and an output from said pressure detecting means, and
• pressure reducing means for reducing an internal pressure of said cryopump,
• wherein upon completion by said cryopump of releasing gases from at least one of said first stage cryopanel surface and said second stage cryopanel surface by maintaining said at least one of said cryopanel surfaces at a fixed temperature, said control means causes said pressure reducing means to quickly reduce an internal pressure of said cryopump to 1/10.sup.3 Pa or less while controlling said heating means so as to maintain said at least one of said cryopanel surface at said fixed temperature, and then causes said cooling means to quickly cool said second stage cryopanel surface to a temperature of 20 K. or lower.

A cryopump comprising:

• at least one of first said second stage cryopanels having respective surfaces onto which a gas is at least one of condensed and absorbed during a pump operation,
• a compressor unit,
• an expander for adiabatically expanding said compressor unit,
• an expander motor for driving said expander,
• cooling means for cooling said surfaces of at least one of said first and said second stage cryopanels, said cooling means allowing a working gas at room temperature and high pressure supplied from said compressor unit to be adiabatically expanded by said expander driven by said expander motor so as to generate cryogenic temperature,
• a temperature sensor for detecting the temperature of the surfaces of said at least one of first stage and second stage cryopanels;
• and
• control means for causing said expander to be one of operationally suspended for a certain period of time or rotated in a reverse direction, based on a detection signal from said temperature sensor, so as to control the temperature of the surfaces of said at least one of said first and second stage cryopanels to be within respective predetermined ranges.

A cold trap comprising:

• a surface of a first stage cryopanel onto which a gas is condensed,
• a compressor unit,
• an expander for adiabatically expanding said compressor unit,
• an expander motor for driving said expander,
• cooling means for cooling the surface of said cryopanel, said cooling means allowing a working gas at room temperature and high pressure supplied from said compressor unit to be adiabatically expanded by said expander driven by said expander motor so as to generate cryogenic temperature,
• a temperature sensor for detecting the temperature of the surface of said cryopanel, and
• control means for causing said expander to be one of operationally suspended for a certain period of time or rotated in a reverse direction, based on a detection signal from said temperature sensor, so as to control the temperature of the surface of said cryopanel to be within a predetermined range.