초록 ▼

A tulip-type check valve is housed in a cylindrical chamber, the length of which is greater than the check valve itself so that during the pressure stroke of the pump, the valve moves forward in its chamber and flexes to permit flow about its periphery. During the suction stroke, the valve closes an

A tulip-type check valve is housed in a cylindrical chamber, the length of which is greater than the check valve itself so that during the pressure stroke of the pump, the valve moves forward in its chamber and flexes to permit flow about its periphery. During the suction stroke, the valve closes and is drawn backward upstream in its chamber and there is a sucking back of liquid between the check valve and the orifice to obviate nozzle the drip.

대표청구항 ▼

In a hand-operated liquid dispenser comprising a. a container, b. a dispenser body secured on the container c. passage means in the body including 1) a dip tube extending into the container, 2) pump means adapted in operation to create negative and positive pressures in the passage means and connect

In a hand-operated liquid dispenser comprising a. a container, b. a dispenser body secured on the container c. passage means in the body including 1) a dip tube extending into the container, 2) pump means adapted in operation to create negative and positive pressures in the passage means and connected to the dip tube, 3) an inlet check valve between the pump means and the dip tube, 4) a discharge orifice, 5) an outlet check valve between the pump means and the orifice, the improvement wherein the outlet check valve comprises an enlarged cylindrical portion of the passage means, the enlarged portion bounded by an annular shoulder at the commencement of the enlarged portion and stop means adjacent the orifice, and a unitary frusto-conical valve having a peripheral skirt resiliently directed downstream and engaging the walls of the enlarged cylindrical portion, and a central stem also extending downstream, the length of the enlarged cylindrical portion of the passage means being greater than the length of the frusto-conical valve, whereby the outlet check valve moves toward the stop means under positive pressure from the pump means and is drawn back toward the shoulder under negative pressure from the pump to effect a suck back of liquid between the outlet check valve and orifice. The method of controlling the movement of liquid through an outlet check valve chamber having a cylindrical wall between a discharge orifice and a manually operated liquid pump wherein a valve element in the chamber has a downstream directed frusto-conical skirt engaging the wall and a central downstream stem, the chamber having a greater length than the valve element, the method including the steps of: a. pumping the liquid downstream and thereby forcing the valve element to the downstream end of the chamber and b. then pumping the liquid upstream and thereby drawing the valve element to the upstream end of the chamber to aspirate liquid downstream from the valve element in an upstream direction to avoid undesired dribbling from the orifice.