FLUID PUMP, DISPENSER HAVING PRODUCT RETRACTION FUNCTION

摘要

PROBLEM TO BE SOLVED: To provide an annular piston relatively movable by opening and closing a supply port communicating with a delivery port via a shaft during a pressurizing stroke and a suction stroke. SOLUTION: While a pump chamber 21 expands for pulling a product in the pump chamber from a delivery passage 13 for avoiding generation of the dribble of the product at the end part of a delivery port 12, the fluid pump dispenser 10 with a piston having a kind of idle movement is provided for maintaining a delivery part in an opening state in a short time after starting the upstroke of respective plungers. This can be done by reducing frictional force acting between a piston 18 and a pump cylinder 16 less than frictional force acting between the piston 18 and the shaft 11.