Double acting piston pump for cryogenic medium

A double-acting piston pump for liquid and gaseous helium comprising:

• a vrtically positioned cylinder having a base portion and a cover portion;
• respective inlet valves disposed in said cover portion and said base portion for admitting the helium into said cylinder and for providing a pressure component of approximately zero against the direction of flow of the helium;
• respective outlet valves disposed in said cover portion and said base portion for discharging the helium from said cylinder, said inlet and said outlet valves having a given flow cross-section;
• respective supply conduits communicating with said inlet valves for supplying the helium thereto, and respective discharge conduits communicating with said outlet valves for conducting the helium therefrom, said inlet and outlet valves having a flow cross-section which is at least approximately the same as said flow cross-section of said conduits;
• a piston slideably mounted in said cylinder;
• a drive rod connected to said piston and extending through one of said portions;
• drive means engaging said drive rod for actuating said piston;
• and
• a housing having a portion defining said cylinder, said drive rod and said drive means being mounted in the remaining portion of said housing whereby said housing is common to said piston, said drive rod and said drive means, said inlet valve in said cover portion being a plate valve comprising a plate movably mounted in said cover portion, said plate having a weight corresponding to a predetermined force value, and a spring engaging said plate for developing a force with respect to the same having a value in the range extending from said force value to a value only slightly greater than said force value.

A double-acting piston pump for liquid and gaseous helium comprising:

• a vertically positioned cylinder having a base portion and a cover portion;
• respective inlet valves disposed in said cover portion and said base portion for admitting the helium into said cylinder and for providing a pressure component of approximately zero against the direction of flow of the helium;
• respective supply conduits communicating with said inlet valves for supplying the helium thereto, and respective discharge conduits communicating with said outlet valves for conducting the helium therefrom, said inlet and outlet valves having a flow cross-section which is at least approximately the same as said flow cross-section of said conduits;
• a piston slideably mounted in said cylinder;
• a drive rod connected to said piston and extending through one of said portions;
• drive means engaging said drive rod for actuating said piston;
• and
• a housing having a portion defining said cylinder, said drive rod and said drive means being mounted in the remaining portion of said housing whereby said housing is common to said piston, said drive rod and said drive means, said inlet valve in said cover portion being a plate valve comprising a plate movably mounted in said cover portion, and a spring engaging said plate for developing a force with respect to the same having a value approximately the same as the force corresponding to the weight of said plate.