| 摘要 |
A manually actuated dispensing pump having a pump body extending transversely above a closure cap (12) adapted for mounting the body at the upper end of a container (C), has an outwardly open pump cylinder (18) for the reception of a reciprocable piston (21) having spaced piston seals (34,36). To facilitate pump priming, the inboard seal (34) is so positioned relative to the inlet port (24) that the inboard seal overlies the inlet port at a predetermined position during the inward pressure stroke of the piston to permit flow of entrapped air from the pump chamber outwardly of the pump cylinder via the annular chamber (44) defined between the piston seals. |
