Throttle cycle cryopumping system for Group I gases

A cold trap system for pumping a Group I gas, comprising:

• a cryopumping surface for exposure inside a vacuum chamber and path means having an inlet and an outlet and thermodynamically connected to said surface for circulating cryogenic refrigerant through said path means and for cooling said surface, in operation, at least one Group I gas freezing on said surface;
• a heat exchanger having a high pressure path with an inlet and an outlet, and a low pressure path with an inlet and an outlet, said paths being in heat transfer relationship to each other, said heat exchanger being enclosed in a housing;
• a refrigerant flow restrictor connected for refrigerant flow between said outlet of said high pressure path of said heat exchange and said inlet of said path means of said cryopumping surface, the outlet of said path means being connected to said inlet of said low pressure heat exchanger path, said heat exchanger and housing being located proximate said cryopumping surface and said flow restrictor, said heat exchanger housing being mountable outside said vacuum chamber wherein said cryopumping surface is to be exposed, and
• connection means between said cryogenic pumping surface and said heat exchanger, said connection means during operation communicating a vacuum within said vacuum chamber with an interior space of said heat exchanger housing.

A cold trap system for pumping a Group I gas, comprising:

• a cryopumping surface for exposure inside a vacuum chamber and path means having an inlet and an outlet and thermodynamically connected to said surface for circulating cryogenic refrigerant through said path means and for cooling said surface, in operation, at least one Group I gas freezing on said surface;
• a heat exchanger having a high pressure path with an inlet and an outlet, and a low pressure path with an inlet and an outlet, said paths being in heat transfer relationship to each other, said heat exchanger being enclosed in a housing;
• a refrigerant flow restrictor connected for refrigerant flow between said outlet of said high pressure path of said heat exchange and said inlet of said path means of said cryopumping surface, the outlet of said path means being connected to said inlet of said low pressure heat exchanger path,
• said heat exchanger and housing being located proximate said cryopumping surface and said flow restrictor, said heat exchanger housing being mountable outside said vacuum chamber wherein said cryopumping surface is to be exposed, and further comprising connection means between said cryogenic pumping surface and said heat exchanger, said connection means isolating a vacuum within said vacuum chamber during operation from an interior space of said heat exchanger housing.

A cold trap system for pumping a Group I gas, comprising:

• a cryopumping surface for exposure inside a vacuum chamber and path means having an inlet and an outlet and thermodynamically connected to said surface for circulating cryogenic refrigerant through said path means and for cooling said surface, in operation, at least one Group I gas freezing on said surface;
• a heat exchanger having a high pressure path with an inlet and an outlet, and a low pressure path with an inlet and an outlet, said paths being in heat transfer relationship to each other, said heat exchanger being enclosed in a housing;
• a refrigerant flow restrictor connected for refrigerant flow between said outlet of said high pressure path of said heat exchange and said inlet of said path means of said cryopumping surface, the outlet of said path means being connected to said inlet of said low pressure heat exchanger path,
• said heat exchanger and housing being located proximate said cryopumping surface and said flow restrictor, wherein said refrigerant is a selected mixture of components for providing a selected temperature span for said cryopumping surface of approximately 20K within a range of temperatures of approximately 80K to 160K.

A cold trap system for pumping a Group I gas, comprising:

• a cryopumping surface for exposure inside a vacuum chamber and path means having an inlet and an outlet and thermodynamically connected to said surface for circulating cryogenic refrigerant through said path means and for cooling said surface, in operation, at least one Group I gas freezing on said surface;
• a heat exchanger having a high pressure path with an inlet and an outlet, and a low pressure path with an inlet and an outlet, said paths being in heat transfer relationship to each other, said heat exchanger being enclosed in a housing;
• a refrigerant flow restrictor connected for refrigerant flow between said outlet of said high pressure path of said heat exchange and said inlet of said path means of said cryopumping surface, the outlet of said path means being connected to said inlet of said low pressure heat exchanger path,
• said heat exchanger and housing being located proximate said cryopumping surface and said flow restrictor, said refrigerant flow restrictor includes a capillary tube, said capillary tube being attached to a cold plate, and said cold plate serving as said cryopumping surface when located inside a vacuum chamber.

A cold trap system for pumping a Group I gas, comprising:

• a cryopumping surface for exposure inside a vacuum chamber and path means having an inlet and an outlet and thermodynamically connected to said surface for circulating cryogenic refrigerant through said path means and for cooling said surface, in operation, at least one Group I gas freezing on said surface;
• a heat exchanger having a high pressure path with an inlet and an outlet, and a low pressure path with an inlet and an outlet, said paths being in heat transfer relationship to each other, said heat exchanger being enclosed in a housing;
• a refrigerant flow restrictor connected for refrigerant flow between said outlet of said high pressure path of said heat exchange and said inlet of said path means of said cryopumping surface, the outlet of said path means being connected to said inlet of said low pressure heat exchanger path,
• said heat exchanger and housing being located proximate said cryopumping surface and said flow restrictor,
• wherein the Group I gas is water vapor, further comprising a drain pan positioned below at least a portion of said cryopumping surface for catching water melted from said cryopumping surface during a defrost cycle, said drain pan having a drain tube that extends through said heat exchanger housing to ambient environment.