LIQUID MATERIAL FLOW CONTROL PUMP

PROBLEM TO BE SOLVED: To prevent contamination of a liquid material by outside air by arranging a gas seal part in a slidingly movable part of a piston to suck in/deliver the liquid material by sliding motion, flowing inert gas here, and enclosing a suction valve and a delivery valve in piping joints welded to a casing. SOLUTION: Inert gas such as nitrogen, argon and helium is passed into this gas seal chamber 7 from an inert gas supply port 8 by defining the gas seal chamber 7 by a gas seal wall 6 between packing 5 and a driving part 4 of a piston 3 fitted/installed in a cylinder 2 formed in a casing 1 of a flow control pump to supply a semiconductor manufacturing liquid material. A suction valve 11 and a delivery valve 12 are enclosed in respective ones by welding suction side and delivery side respective piping joints 9 and 10 to upper and lower parts of the casing. The liquid material is sucked in/delivered according to sliding motion of the piston 3, but in this case, the delivery valve 12 is set to as to be actuated by a pressure difference of about 1 to 100 kg/cm by a spring, etc.