Pump for Under Counter Dispensing System

A pump for simultaneously dispensing a first fluid and a second fluid comprising:

• a piston chamber-forming body disposed about a central axis,
• a piston-forming element received in the piston chamber-forming body coaxially slidable inwardly and outwardly therein between an outward extended position and an inward retracted position,
• the piston chamber-forming body having an inner tubular member extending axially between an axial inner end of the inner tubular member and an axially outer end of the inner tubular member,
• the inner tubular member having a circumferential side wall defining a central passage axially through the inner tubular member open at the axial outer end of the inner tubular member,
• the axially outer end of the inner tubular member open to a discharge outlet,
• the piston chamber-forming body having an outer tubular member extending axially between an axial inner end of the outer tubular member and an axially outer end of the outer tubular member,
• the outer tubular member disposed coaxially about the inner tubular member,
• the piston chamber-forming body having an annular flange fixedly connecting the outer tubular member to the inner tubular member, the annular flange extending radially inwardly from the outer tubular member to the inner tubular member closing the inner end of the outer tubular member,
• an annular first chamber defined annularly between the outer tubular member and the inner tubular member axially outwardly of the annular flange, the first chamber closed at an annular axially inner end of the first chamber by the annular flange and open axially outwardly through the axially outer end of the outer tubular member,
• the outer end of the inner outer member in communication with a source of the first fluid,
• at least one axially and circumferentially extending guide slot extending radially through the side wall of the inner tubular member between the first chamber and the central passage,
• the inner end of the inner tubular member in communication with a source of the second fluid,
• a second chamber defined inside the inner tubular member axially inwardly of the guide slot,
• the piston-forming element having an axially extending tubular hollow inner stem extending between an axially inner stem inner end and an axially inner stem outer end,
• the inner stem having axially extending passageway therethrough,
• the inner stem coaxially received within the inner tubular member for reciprocal coaxial sliding therein between the extended position and the retracted position with the inner stem inner end coaxially slidably received in the second chamber and the inner stem outer end coaxially slidably received in the inner tubular member axially outwardly of the guide slot,
• the piston-forming element having an annular sealing member coaxially slidably received in the first chamber spanning radially between the outer tubular member and the inner tubular member,
• the piston-forming element having at least one spoke member extending radially through the guide slot to fixedly couple the inner stem to the annular sealing member with the spoke member being axially slidable in the guide slot with coaxial sliding of the piston-forming element relative to the piston chamber-forming body between the extended position and the retracted position,
• the inner stem coaxially slidably received in the second chamber defining with the second chamber, a second pump which, with reciprocal coaxial sliding of the piston-forming element relative the piston chamber-forming body, draws the second fluid from the source of the second fluid and discharges the second fluid into the passageway, axially outwardly through the passageway and out the passageway outer end into the central passage of the inner tubular member,
• the annular sealing member having a radially outer seal member engaging the outer tubular member to prevent fluid flow outwardly therebetween and a radially inner seal member engaging the inner tubular member axially outwardly of the guide slot to prevent fluid flow outwardly therebetween,
• the annular sealing member coaxially slidably received in the first chamber defining with the first chamber a first pump which, with reciprocal coaxial sliding of the piston-forming element relative the piston chamber-forming body, draws a first fluid from the atmosphere into the first chamber and discharges the first fluid from the first chamber radially inwardly through the guide slot to the central passage,
• wherein with reciprocal coaxial sliding of the piston-forming element relative the piston chamber-forming body, the second fluid discharged by the second pump and the first fluid discharged by the first pump are simultaneously passed through the central passage and out the discharge outlet.