Abstract: Reciprocating pumps are disclosed. Particularly, reciprocating pumps including pressure chambers and fluid chambers defined by flexible members are disclosed. The volume of the pressure chambers and fluid chamber may be controlled using a piston driven by the flow of a control fluid to a pressure chamber and associated piston chamber. The flow of the control fluid may be directed to a first pressure chamber and associated piston chamber or a second pressure chamber and associated piston chamber. A pneumatically driven switch or an electrically driven switch may direct the flow of control fluid. The electrically driven switch may be controlled with a timer, a pressure sensor, or an optical sensor. The reciprocating pump requires minimal modification to permit the use of a pneumatic switch or electrical switch.

Abstract: A pneumatically actuated reciprocating fluid pump and spool valve combination is pneumatically shifted by pressurized air that exhausts from a respective pressurized bellows, diaphragm, or piston chamber, as the bellows, etc. nears the end of its pressure stroke (the exhaust stroke of the pumped fluid). This pressurized air exhausts from the bellows chamber via a shift piston and canister mechanism that seals on the face of the shift canister, rather than on its periphery. The pressurized air exhaust from the bellows chamber acts on the end of the valve spool element to shift the spool element to its opposite position, which reverses the application of pneumatic pressure and atmospheric exhaust between the two bellows chambers to actuate the reciprocating pump.

Abstract: An oil level control system uses an available pressure source to operate a fluid motor which is integrally connected with a reciprocating fluid pump. The pump has an inlet passage disposed at the desired oil level in a primary reservoir. A pair of one-way valves cooperate with the pump to draw oil, above the desired level, from the primary reservoir and deliver the oil to a secondary reservoir. A restricted drain back passage permits the fluid to return to the primary reservoir to ensure that the desired level is maintained. The fluid motor is connected with an accumulator such that the initial portion of the stroke is operated by the pressure source of the pump stroke. The motor is driven by pressurized fluid in the accumulator.