US 6,685,443 B2 · Pneumatic reciprocating pump

Abstract

A pneumatically-actuated reciprocating fluid pump and shuttle valve combination operates in an “air-assist” mode and a “non-air-assist” mode. In the non-air-assist mode, the shuttle valve is shifted by a blast of pressurized supply air from the pneumatic chamber in its pumping stroke as the flexible diaphragms and drive shaft reach the end of their pumping stroke. This blast of pressurized air used to shift the shuttle valve has the effect of reducing the air pressure in the pneumatic chamber immediately prior to the point in time that the drive shaft reaches the end of its stroke in order to provide a cushioning effect at the end of each pumping strokes cycle, in order to lessen the effect of the drive shaft and diaphragms abruptly reversing direction at full air pressure. In the air-assist mode, a secondary source of compressed air is utilized to shift the shuttle valve, rather than drawing pressurized air from the pneumatic chamber during its pumping stroke. In the air-assist mode, the full effect of the pressurized air to the pump is directed to pump fluid through the pump, and is not lessened by tapping a minute amount compressed air at the end of each pumping stroke cycle for shifting the shuttle valve.

Claims18

Dependent claims

A pneumatically shifted reciprocating fluid pump comprising:

a body defining two pumped fluid pumping chambers;
driving means defining a pneumatically driven driving chamber associated with each respective pumped fluid pumping chamber;
connecting means connecting the respective driving means;
and
a pneumatically actuated control valve for supplying a first drive fluid sequentially to each pneumatically actuated driving chamber for effecting reciprocal pumping of the respective driving means,
wherein the pump is convertible between two modes of operation wherein in a first mode the pump includes first pneumatically actuated switching means associated with each respective driving means for permitting drive fluid to selectively exhaust from respective pneumatically actuated driving chambers to shift the control valve for sequentially supplying the drive fluid to respective pneumatically actuated driving chambers for reciprocally actuating respective pumping chambers;
and a second mode wherein the pump includes second pneumatically actuated switching means associated with the connecting means for permitting an external supply of drive fluid to selectively shift the control valve for sequentially supplying the external supply of drive fluid to respective pneumatically actuated driving chambers for reciprocally actuating respective pumping chambers.

4 more elements

Dependencies are inferred from the claim text.

Pneumatic reciprocating pump

Life of this patent

Pneumatic reciprocating pump

Life of this patent

Abstract

Claims18