摘要 |
A precompression pump is disclosed with a sliding inlet valve seal. In a first embodiment, the valve seal has sealing and retention surfaces which interact with sealing and retention surfaces on a bead on the inner wall of the pump chamber, to seal the pump inlet and retain the inlet seal respectively. In a second embodiment, the seal has friction tabs which engage the outer wall of the pump chamber. On the upstroke of the piston, these tabs engage a bead on the inner wall of the pump chamber, causing the tabs to rotate about a hinge, increasing the outer diameter of the seal. The result is improved frictional engagement of the seal with the inner wall, resulting in improved retention of the seal.
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