| 摘要 |
PROBLEM TO BE SOLVED: To desirably deliver a high viscosity fluid without providing discharge ports of various sizes by a method wherein a discharge valve is opened in a compression stroke by a relative sliding action between a hollow rod and a piston to allow contents to be delivered through the hollow rod. SOLUTION: A plug member 32 is fixed to the forward end of a hollow rod 22 constituting a discharge passage from a pump room 4 and a piston 26 is provided between the rod 22 and the member 32 so as to be slidable within a limited range. An annular protrusion is provided on the underside of the piston 26 for engagement in an annular groove provided on the upper side of the member 32 to constitute an openable discharge valve. If a pump plunger 12 is pushed downward, the rod 22 is lowered slightly ahead of the piston 26 by the friction between the piston 26 and a cylinder 6 so that the discharge valve is opened and the contents is delivered through the rod 22. In a return suction step of the piston 26, the discharge valve is closed so that the contents are drawn into the pump room 4. |
