Out-of-fluid detector for reciprocating pumps

摘要

A dynamic displacement sensor for detecting an out-of-fluid condition in a liquid delivery system detects an increased amplitude of pump motion of a reciprocating air pump and provides an output signal upon detecting the increased amplitude motion. The detector includes a spring-mass combination supported within a housing such that the mass is movable along a defined axis of the housing, with the spring applying a restoring force to the mass when the mass moves away from its static position. The detector is attached to the pump with its defined axis aligned parallel with the pump axis. A sensor within the housing is triggered to change state when the mass is displaced by pump motion of a predetermined amplitude and frequency, thereby providing an output signal indicating an out-of-fluid condition.