Patent ID: 7503176

Claim:
A liquid pump comprising: a fluid vessel in which working fluid is filled and the working fluid can move; a heating device for heating the working fluid in the fluid vessel and vaporizing the working fluid; a cooling device for cooling down and liquidizing the steam vaporized by the heating device; a discharge check valve provided at an outlet passage of the pump, and opening the outlet passage by fluid flow caused by expansion pressure of the steam to thereby discharge the working fluid to an outside; and an inlet check valve provided at an inlet passage of the pump, and opening the inlet passage by fluid flow caused by liquidation of the working fluid to thereby suck the working fluid from the outside; wherein the fluid vessel comprises: a U-shaped pipe portion having a bending pipe portion and pair of vertically extending straight portions extending from the bending pipe portion, wherein the bending pipe portion is arranged at a lower most position of the U-shaped pipe portion; wherein the heating device and the cooling device are provided at one of the straight pipe portion, and wherein the discharge check valve and the inlet check valve are respectively provided in fluid passages connected to the other straight pipe portion.