Dispensing pump

Abstract

A dispensing pump for application to a product container includes an elongated housing having a recess in a sidewall thereof and a flexible bulbous diaphragm seated over the recess for a trigger-type actuation as the housing is gripped in the manner of a handle. A variable volume pump chamber is defined by the diaphragm together with the recess, and an inlet passage is provided in the housing through which the product passes from the container into the recess. The diaphragm has an annular inner skirt for closing the inlet passage in response to axial deformation of the diaphragm, as well as intermediate and outer annular skirts. The intermediate skirt has a lower free edge portion normally covering a discharge port in the housing which communicates with the pump housing, and the outer skirt has a lower free edge portion normally covering a vent port in the housing which communicates with the atmosphere. The lower edge portions of the intermediate and outer skirts are of resilient flexible materials so as to respectively uncover the discharge and vent ports in response to a given fluid pressure therewithin. Accordingly, the inlet passage is closed upon depression of the diaphragm and the discharge passage is simultaneously uncovered to permit the contents of the diaphragm to be discharged. Upon release of the diaphragm the vacuum pressure thereby created effects a closing of the discharge passage and an opening of the inlet passage for refilling of the pump chamber. As the dispensable product is withdrawn from the container, the vacuum pressure therein created effects an opening of the vent passage and permits air to flow into the container.