LIQUID FEED PUMP

PURPOSE:To perform the stable feed of liquid by a method wherein check balls different in size and weight are combined together in a check valve and a resonance point is changed, in a liquid feed pump having a ball type check valve wherein two balls in a stacked state both on the suction side and the delivery side are used in the cylinder of a plunger pump. CONSTITUTION:A liquid feed pump comprises a drive part 26 consisting of a pulse motor 1, pulleys 2 and 3, and cams 5 and 6; and a liquid feed mechanism part 27 consisting of cylinders 9 and 10 having check valves 7 and 8 for suction and delivery. The cylinders 9 and 10 are interconnected in series and a solvent 29 is fed in a one-way by opening and closing the check valves 7 and 8 in linkage with reciprocation of plungers 11 and 12. In this case, each of the check valves 7 and 8 is formed in such a manner that a large check ball 18 and a small check ball 21 are vertically stacked with a packing 19 therebetween and contained in ball chambers 17 and 20, respectively. Since resonance point generated by the large and small balls are different from each other, the stable feed of liquid is provided.