Method and apparatus for controlling refrigerant gas in a low pressure refrigeration system

[8. The method according to claim 1 further including the steps of:

• sensing the pressure of refrigerant gas in said refrigerant vessel;
• and
• terminating the removing step when the sensed pressure reaches a
• predetermined value.] 9. A system for controlling the pressure of refrigerant gas in the refrigerant vessel of a low pressure refrigeration system, the refrigerant vessel holding both liquid and gas refrigerant, the system comprising:
• a container;
• a thermally conductive member disposed in said container, said member having a surface;
• means for heating said member to a temperature at which liquid refrigerant in contact with said member surface will vaporize;
• means for removing liquid refrigerant from said vessel;
• means for applying the removed liquid refrigerant to said member surface within said container, whereby said removed liquid refrigerant vaporizes upon contacting said member surface;
• [and]
• means for returning vaporized refrigerant from said container to said vessel[.];
• means for sensing the pressure of refrigerant gas in said vessel;
• and
• means responsive to said pressure sensing means for controlling said
• removing means.

[10. The system according to claim 9 further comprising:

• means for sensing the pressure of refrigerant gas in said vessel;
• and
• means responsive to said pressure sensing means for controlling said
• removing means.] 11. The system according to claim 9 wherein said removing means includes a pump and said applying means includes a spray nozzle coupled to receive removed liquid refrigerant from said pump and
• direct a spray thereof toward said member surface. 12. The system according to claim 9 further comprising:
• means for collecting from said member surface non-volatile liquid which had been mixed with said removed liquid refrigerant;
• and
• means for transporting the collected non-volatile liquid to a location
• remote from said refrigerant vessel. 13. The system according to claim 12 wherein said member surface is downwardly concave and said collecting means includes a conduit formed in said member and opening to said member surface at a location on said member surface to which non-volatile liquid
• is propelled under the influence of gravity. 14. The system according to claim 13 further comprising shield means interposed between said applying means and said conduit opening on said member surface for preventing the direct application of said removed liquid refrigerant to said member
• surface in the immediate vicinity of said conduit opening. 15. The system according to claim 9 further comprising:
• means for sensing the temperature of said member;
• and means responsive to
• said temperature sensing means for controlling said heating means. 16. The system according to claim 9 wherein said removing means includes an electrically powered pump , [and] said applying means includes a spray nozzle coupled to receive removed liquid refrigerant from said pump and direct a spray thereof toward said member surface, and the [system further comprising:
• means for sensing the pressure of refrigerant gas in said vessel;
• and]
• means responsive to said pressure sensing means [for controlling] controls the application of electric power to said pump.
• The system according to claim 16 further comprising:
• means for sensing the temperature of said member;
• and
• means responsive to said temperature sensing means for controlling said
• heating means. 18. The system according to claim 9 wherein the refrigeration system includes a compressor having an oil sump, said member surface is downwardly concave, and said member is formed with a conduit therethrough which opens to said member surface at a location thereon to which non-volatile liquid which had been mixed with said removed liquid refrigerant and applied to said member surface is propelled under the influence of gravity, the system further comprising:
• means communicating with said member conduit and said compressor oil sump for providing a flow path for said non-volatile liquid from said container
• to said compressor oil sump. 19. The system according to claim 18 further comprising valve means associated with said flow path providing means for
• regulating the flow of said non-volatile liquid. 20. The system according to claim 18 wherein said removing means includes a pump and said applying means includes a spray nozzle coupled to receive removed liquid refrigerant from said pump and direct a spray thereof toward said member surface, the system further comprising:
• a shield plate mounted to and spaced from said member surface, said shield plate being so sized and positioned that removed liquid refrigerant sprayed from said nozzle is prevented from directly reaching said member surface in the immediate vicinity of the opening of said conduit to said member surface.