| 摘要 |
An improved container closure and dosing pump or syringe has a piston formed with a truncated cone-shaped face. A spring-biased operator yieldably holds the piston sealed deeply in a dosing chamber from which it can be shifted to project essentially by the height of the truncated piston face to completely scavenge the chamber. The device is formed of only three injection molded plastic parts and a return spring, to effect inexpensive production.
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