| 摘要 |
PROBLEM TO BE SOLVED: To draw liquid remaining in a discharge path into a cylinder as much as possible, irrespective of the viscosity of the liquid, by raising back suction effect. SOLUTION: A pump is provided with a base cap 1 which is engaged with the mouth of a vessel and keep the vessel in a sealed condition, a cylinder 2 which is fixedly held by the base cap 1 and inserted into the vessel through the mouth, a piston rod 3 which has a through path 3a for permitting liquid in the vessel to path therethrough and is reciprocally movable in the cylinder 2, and a pressing head 5 which is connected to the rear end of the piston rod 3 and sucks and pressurizes the liquid in the vessel through an on/off valve 2a operated by the reciprocating motion of the piston rod 3 in the cylinder 2, and discharges the liquid through the through path 3a. The piston rod 3 is provided, in its through path 3a, with a valve element 7 which closes the through path 3a at the time of sucking liquid and opens the through path 3a by floating in liquid at the time of pressurization. Very small gasp t are provided between the through path 3a and the valve element 7, so that the movement of the valve element 7 is delayed before the through path 3a is closed, and the liquid remaining in the space between the valve element 7 and a nozzle is drawn into the through path 3a and/or the cylinder 2. |
