Patent ID: 8702399

Claim:
A pump apparatus including: a housing having an inlet for admitting to the housing a material to be pumped, and a delivery outlet connected to a product line; an inlet knifegate valve on the inlet; an outlet knifegate valve on the outlet; a common actuator mechanically interconnecting the inlet knifegate valve and the outlet knifegate valve to directly actuate the cyclic operation of the inlet knifegate valve and the outlet knifegate valve; an ejector assembly having a compressed air driven venturi and an ejector valve after the compressed air driven venturi, the ejector valve being opened to reduce the pressure in the housing via the compressed air driven venturi to admit the material to the housing, and being closed to pressurize the housing, the waste air from the compressed air driven venturi being vented into the product line downstream of the knifegate outlet valve; and a controller operating the common actuator to actively open and close the inlet knifegate valve and the outlet knifegate valve in concert with the ejector valve.