Patent ID: 7004356

Claim:
A pump used in connection with a container filled with a liquid, the pump comprising: a) a pump body defining an air chamber and a liquid chamber separated by a seal; b) a cup slidably received within said pump body at said liquid chamber, said cup being in selective communication with the liquid, whereby said cup is filled with liquid when the pump is in an idle position; c) a head assembly slidably mounted within said pump body and sealingly engaging said air chamber; d) a plunger extending from said head assembly through said seal and into said cup and slidably received therein; and e) a mixing chamber in selective fluid communication with said liquid chamber and said air chamber, said mixing chamber opening externally of said head assembly, whereby operation of the pump causes liquid from the liquid chamber and air from the air chamber to mix in the mixing chamber to form a foam which is discharged from the head assembly; f) wherein said cup is spaced from an end of said pump body by a first spring adapted to urge said cup toward said plunger; g) wherein said plunger is adapted to bottom out in said cup to empty said liquid chamber; wherein said air chamber is sized to allow further inward movement of said head assembly after said plunger bottoms out, whereby said further inward movement of said head assembly compresses said spring and forces a blowing charge from said air chamber through said mixing chamber and said head assembly to evacuate any foam remaining therein.