Control apparatus for a positive displacement reciprocating pump

A positive displacement reciprocating pump for conveying a liquid or gaseous fluid, and comprising

• a fluid enclosure,
• a flexible diaphragm sealably disposed in said enclosure and dividing the enclosure into a pumping chamber on one side of the diaphragm and an actuating chamber on the other side thereof,
• an inlet valve and a separate outlet valve each communicating with said pumping chamber,
• control means for intermittently supplying a pressurized working fluid to said actuating chamber so as to intermittently move said diaphragm in a direction toward said pumping chamber and thereby discharge the conveyed fluid from such chamber, said control means including a source of pressurized working fluid, a working fluid line extending between said source and said actuating chamber, and valve means operatively connected to said working fluid line and including a slide which is movable between an open position wherein said line is opened to a discharge tank or the like to release the pressure therein, and a closed position wherein the pressure of said working fluid is maintained in said line and delivered to said actuating chamber, said control means further including means for actuating said valve means in a sequence of working times and idle times, with each of the working times consisting of a closed time period wherein pressure is maintained in said working fluid line and an open time period wherein said pressure is released in said line, with each of said working times being of essentially uniform duration and with the closed time periods of the working times being of essentially uniform duration which is sufficient to move said piston means along its predetermined stroke, and with the pressure in said line being released during said idle times.

In an absorption heat pump apparatus including a solution containing a solvent such as water and a heat carrier such as ammonia, means for separating the heat carrier from the solvent, means for conveying the separated heat carrier between a condenser and evaporator to sequentially release and absorb heat, means for absorbing the heat carrier into the solvent, and a pump for circulating the solution through the apparatus, the improvement wherein said circulating pump comprises

• a fluid enclosure
• movable piston means disposed in said enclosure and sealably dividing the enclosure into a pumping chamber on one side of the piston means and an actuating chamber on the other side thereof,
• an inlet valve and a separate outlet valve each communicating with said pumping chamber,
• control means for intermittently supplying a pressurized working fluid to said actuating chamber so as to intermittently move said piston means along a stroke which extends in a direction toward said pumping chamber and thereby discharge the conveyed fluid from such chamber, said control means including a source of pressurized working fluid, a working fluid line extending between said source and said actuating chamber, and valve means operatively connected to said working fluid line for intermittently opening said line to a discharge tank or the like to release the pressure therein, said control means further including means for actuating said valve means in a sequence of working times and idle times, with each of the working times consisting of a closed time period wherein pressure is maintained in said working fluid line and an open time period wherein said pressure is released in said line, with each of said working times being of essentially uniform duration and with the closed time periods of the working times being of essentially uniform duration which is sufficient to move said piston means along its predetermined stroke, and with the pressure in said line being released during said idle times.