Patent ID: 9541074
Date: 2017-01-10
CPC Classifications: F04B

Claim:
1. An air-driven pump comprising: a source of pressurized air; a first pump unit including a first pump chamber, a first air chamber and a first end of stroke position; a second pump unit including a second pump chamber, a second air chamber and a second end of stroke position, an efficiency valve system pneumatically between the source of pressurized air and the first and second air chambers; a directional control valve pneumatically between the efficiency valve system and the first and second air chambers; a first air passage extending between the efficiency valve system and the directional control valve; a second air passage extending between the efficiency valve system and the directional control valve, the directional control valve shifting at the end of stroke positions to control air communication from the first and second air passages to the first and second air chambers, respectively, the efficiency valve system including a first valve position defining unrestricted air communication between the source of pressurized air and the first air passage and restricted air communication between the source of pressurized air and the second air passage and a second valve position defining unrestricted air communication between the source of pressurized air and the second air passage and restricted air communication between the source of pressurized air and the first air passage, the efficiency valve system shifting between the first and second valve positions before the directional control valve has shifted.