US 4,402,432 AGranted

Leak-proof dispensing pump

OwnerDouglas F. Corsetteinventor

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Abstract

A dispensing pump having a unitary plunger defining a main pump chamber and functioning as a discharge valve upon accumulation of pressure causing the plunger to shift open, includes a container vent which is positively sealed against leakage therethrough even upon nudging the plunger during storage, shipment and handling of the pump. The pump includes a fixed position and a reciprocable plunger head having a discharge passage, the inside of the head and the top of the piston being complementarily contoured for expelling accumulated air from the pump chamber directly out of the discharge during priming. Otherwise, the pump chamber may be placed in communication with a vent chamber which opens into the container through the vent so that any accumulated air in the pump chamber may be vented into the container as an aid in priming. The volume beneath the plunger head may be enclosed as an air chamber so that the air therein may be vented into the container upon opening the container vent to assist in pump priming. And, the plunger is designed to effect a quick or a slow opening of the discharge passage.

Claims15

Dependent claims

In a liquid dispenser comprising a pump body sealingly mounted on a container of flowable product to be dispensed, said body having a container vent opening therein and a stationary piston thereon, an annular plunger resiliently urged into a fully raised position and mounted for reciprocation on said piston to define therewith a variable volume pump chamber, a valve controlled inlet passage in said piston, a plunger head slidably disposed on said plunger and having a discharge passage adapted to be opened and closed by said plunger upon an increase in pressure within said chamber,

the improvement wherein means are provided for opening and closing said vent opening upon reciprocation of said plunger, said means comprising a vertical first cylindrical wall spaced from and surrounding said piston so as to therewith define a vent chamber which is in open communication with the interior of the container via said vent opening, means defining a container vent passage extending from the interior of the container via said vent opening and said open vent chamber, outwardly of said plunger and outwardly of said plunger head, said opening and closing means further comprising skirt means on said plunger in sealing engagement with an inner surface of said wall for closing said vent passage while said plunger is in its raised position and during an initial downstroke reciprocation thereof, said skirt means being further adapted to open said vent passage upon a further downstroke reciprocation of said plunger, whereby the interior of the container is vented to atmosphere only during said further downstroke reciprocation, and any leakage of product from the container through said vent passage is positively prevented while said plunger is in said raised position and during said initial downstroke.

Dependencies are inferred from the claim text.