Liquid dispensing pump

A liquid dispensing pump, comprising a pump body having a pump cylinder defining a pump chamber, said cylinder having an end wall containing a coaxial inlet port for communication with a source of flowable product to be dispensed, and said cylinder having a side wall containing an outlet port opening radially from said chamber, a pump piston reciprocable in said cylinder, a thimble-shaped valving element located in said cylinder and having an end wall defining an inlet check valve controlling said inlet port, said end wall having openings surrounding said inlet check valve through which product is admitted into said chamber from said inlet port, said valving element further having an annular resiliently flexible lip seal defining an outlet check valve, said lip seal being in engagement with said side wall of said pump cylinder in an outlet closing position and being flexible radially inwardly away from said side wall in an outlet opening position in response to an increase in pressure within said pump chamber, resilient means extending between said piston and said valving element, means for manually reciprocating said piston against the force of said resilient means, said pump body having acylindrical wall containing a vent opening, said piston having an annular vent seal in engagement with said cylindrical wall for closing said vent opening, and means at said cylindrical wall for disengaging said vent seal from said cylindrical wall to thereby establish in a pumping position a vent passage for venting the container through said vent opening.

A liquid dispensing pump, comprising a pump body, a separate closure cap engaged with said pump body for mounting said pump body on a container of flowable product to be dispensed, said pump body including outwardly opening cylinder means having a bore of predetermined diameter and a counterbore of relative greater diameter, said cylinder means being disposed at an angle to the central axis of said closure cap, a pump piston reciprocable in said cylinder means, said piston having piston seal means in sliding sealing engagement with the wall of said bore and defining together therewith a variable volume pump chamber, said pump body having inlet and outlet means for delivering product into and out of said pump chamber, means for manually reciprocating said piston, said cylinder means including a vent port establishing communication between the interior of said counterbore and the interior of the container, said piston having an annular seal means in sliding sealing engagement with the wall of said counterbore for sealing off said vent port from the atmosphere in a non-pumping position, and means at said wall of said counterbore for disengaging said annular seal means from said wall of said counterbore to thereby establish in a pumping position a vent passage for venting the container through said vent port, said annular seal means being located outwardly of said disengaging means in said non-pumping position.

A liquid dispensing pump, comprising a pump body, a separate closure cap engaged with said pump body for mounting said pump body on a container of flowable product to be dispensed, said pump body including outwardly opening cylinder means having a bore of predetermined diameter and a counterbore of relative greater diameter, said cylinder means being disposed at an angle to the central axis of said closure cap, a pump piston reciprocable in said cylinder means, said piston being in sliding sealing engagement with the wall of said bore and defining together therewith a variable volume pump chamber, said pump body having inlet and outlet means for delivering product into and out of said pump chamber, means for manually reciprocating said piston, said piston having an annular lip seal in sliding sealing engagement with the wall of said counterbore for defining an annular chamber therewith, said cylinder means including a sump drain port establishing communication between said annular chamber and the interior of the container, said port being inwardly spaced from said lip seal in non-pumping and pumping positions of said piston, whereby any leakage of product from said pump chamber around said piston is purged from said annular chamber into the container through said sump drain port, any leakage of product is prevented from the container through said port and outwardly of said cylinder means, and any abrasion of said piston or said lip seal by the wall of said port, during pumping or assembly of the piston, is avoided.

A liquid dispensing pump, comprising a pump body, a separate closure cap engaged with said pump body for mounting said pump body on a container of flowable product to be dispensed, outwardly opening cylinder means in said pump body, said cylinder means being disposed at an angle to the central axis of said closure cap, a pump piston reciprocable in said cylinder means and defining together therewith a variable volume pump chamber, said pump body having inlet and outlet means for delivering product into and out of said pump chamber, means for manually reciprocating said piston, said cylinder means including a cylindrical wall, a sump drain port located in said wall at a position lying outwardly of said pump chamber, said piston having an annular lip seal defining an annular chamber with said wall and being spaced outwardly of said port in both pumping and non-pumping positions of said piston, said annular chamber being in communication with said port, said lip seal sealingly engaging said wall at the end of outward reciprocation of said piston for sealing said chamber closed to the atmosphere, whereby any leakage of product from said pump chamber around said piston is purged from said annular chamber into the container through said port, any leakage of product is prevented from the container through said port and outwardly of said cylinder means, and any abrasion of said piston or said lip seal by the wall of said port, during pumping or assembly of said piston, is avoided.