Pump piston cylinder assembly with exterior ring seals

In a pump, the improvement comprising:

• a piston member;
• a cylinder block constructed of a low coefficient of friction material and having an elongated piston-receiving chamber with a smooth uninterrupted sidewall formed therein, and a first channel intruding from the external surface of said cylinder block to define a sidewall portion of reduced cross-section for said chamber, said sidewall portion being flexible and said piston member configured for close-fitting telescopic insertion into said chamber;
• and
• sealing means associated with said channel and said sidewall portion for deforming said sidewall portion into sealing engagement with the surface of said piston member.

A pump assembly comprising:

• a support member;
• a base member mounted on said support member;
• a cylinder block pivotally mounted on said base member and having a piston-receiving chamber therein, said piston-receiving chamber having a longitudinal axis aligned with the point of pivotal mounting of said cylinder block and said base member, and a fluid port communicating with said piston-receiving chamber, said fluid port having an externally opening mouth, said base member having an inlet passageway and an outlet passageway with an inlet port and an outlet port respectively disposed in closely spaced-apart relation symmetrically about a line through said point of pivotal mounting and the midpoint between said inlet and outlet ports;
• biasing means for biasing said cylinder block and said base member into abutment;
• a rotatable eccentric member mounted on said support member proximate one end of said cylinder block;
• a piston having a portion at a first end thereof positioned in said piston-receiving chamber and connected at a second end thereof opposite said first end to said eccentric member, said piston-receiving chamber having a flexible sidewall portion of reduced thickness positioned adjacent to the surface of said piston and extending transversely of and in surrounding relation to said piston;
• resilient compressing means in surrounding relation to said flexible sidewall portion for deforming said flexible sidewall portion uniformly into contact with the surface of said piston member;
• and
• drive means for rotatably driving said eccentric member whereby said piston member is reciprocated in said piston-receiving chamber and said cylinder block is pivoted on said base member between points whereby said mouth of said fluid port is alternately positioned in communication with said inlet and outlet ports.

A pump assembly comprising:

• a base member having an intake passageway and an exhaust passageway;
• a cylinder block mounted on said base member, said cylinder block and said base member including matching sealing surfaces abutting one another, said intake and exhaust passageways having an intake port and an exhaust port respectively disposed in closely spaced-apart relation on said sealing surface of said base member, said cylinder block including an elongated cylindrical portion having an elongated cylindrical chamber formed therein, said chamber having a smooth uninterrupted sidewall, an end wall and a circular opening opposite said end wall, said cylindrical block having a fluid port with an externally opening mouth on its sealing surface and with an internally opening mouth in fluid communication with said chamber adjacent said end wall;
• said base member and said cylinder block being formed of a plastic-like material having a coefficeint of friction less than 0.5, and said cylindrical portion having first and second outwardly opening channels formed therein in closely spaced-apart relation therearound with one of said channels adjacent said circular mouth, said channels defining flexible annular sidewall portions of said sidewall;
• a cylindrical piston adapted for close-fitting insertion in said chamber;
• an O-ring in each of said channels of sufficient dimension to collapse said annular sidewall portions radially inwardly against the cylindrical sidewall of said piston;
• and
• drive means for driving said piston and said cylinder block whereby said piston is reciprocated in said chamber and said externally opening mouth is alternatively positioned in communication with said intake port and said exhaust port during each cycle of the piston's motion.

In fluid handling apparatus and the like, the improvement comprising:

• an elongated piston member;
• a cylinder block having a piston-receiving chamber formed therein and a fluid port communicating with said chamber, a portion of the sidewall of said chamber in contact with said piston member being composed of a flexible, low coefficient of friction material and sized for close-fitting engagement with said piston member;
• and
• sealing means in the form of an elastic O-ring extending around the external surface of said flexible portion of said cylinder block whereby to force said flexible portion into contact with the surface of said piston member around the perimeter of said piston member.