Ambient air timing device

Abstract

An air timing device for a high pressure reciprocating injector pump 14 employing a piston or movable wall 50 and orifice 48 combination that is mechanically reset on the suction stroke of the pump includes a bellows 42 defining a variable volume chamber 44 including at least one movable wall. An adjustable orifice 46 in parallel with a check valve is defined in the chamber to provide adjustable flow out of the chamber and full flow through the check valve into the chamber. The wall is connected to a piston 18 of the reciprocating pump by an arm 38 that is fixedly secured to the piston and slideably secured to the wall. A selector valve 62 is also included for directing supply fluid to a selected side of the pump piston to reciprocate the pump. The valve includes a spool valve connected to the wall by a second arm. The fluid within the chamber defined by the bellows may be employed in a closed system wherein the fluid is exhausted from the chamber to an external chamber for reuse during the next stroke of the pump or in an alternative embodiment, the fluid may be exhausted to the atmosphere.

Dependencies are inferred from the claim text.