Proportioning pump

A valveless reversible positive displacement pump, comprising:

• a closed end cylinder including two fluid port means for allowing fluid to flow into and out of said cylinder adjacent said closed end;
• piston means reciprocably and rotatably drivable in said cylinder, said piston means including a reduced area portion on one free end thereof adjacent said cylinder closed end, which portion alternately communicates with each of said fluid port means as said piston means are reciprocably and rotatably driven to draw fluid in one fluid port means and expel it through the second fluid port means;
• and
• end cap means forming at least a portion of said cylinder closed end for relieving positive and negative pressures caused by said piston means when both said two fluid port means are closed by said piston means without introducing significant error in pumping accuracy.

A valveless reversible positive displacement pump, comprising:

• a closed end cylinder including two fluid port means for allowing fluid to flow into and out of said cylinder adjacent said closed end;
• piston means reciprocably and rotatably drivable in said cylinder, said piston means including a reduced area portion on one free end thereof adjacent said cylinder closed end, which portion alternately communicates with each of said fluid port means as said piston means are reciprocably and rotatably driven to draw fluid in one fluid port means and expel it through the second fluid port means;
• and
• said piston means being driven by compliant ball support means for self adjusting and compensating for assembly and operating misalignment of said piston means.

A valveless reversible positive displacement pump, comprising:

• a closed end cylinder including two port means for allowing fluid to flow into and out of said cylinder adjacent said closed end;
• piston means reciprocably and rotatably drivable in said cylinder, said piston means including a reduced area portion on one free end, thereof adjacent said cylinder closed end, which portion alternately communicates with end of said fluid port means as said piston means are reciprocably and rotatably driven to draw fluid in one fluid port means and expel it through the second fluid port means;
• and
• said piston means being driven by ball and socket means which are separate from but biased together between said drive shaft means and said piston means.