| 摘要 |
A pump is mounted in one end of a cylindrical container for storing a liquid, for drawing the liquid stored in the cylindrical container and discharging the drawn liquid out of the cylindrical container. A piston is slidably disposed in the opposite end of the container in keeping the liquid sealed in the cylindrical container. The piston is movable toward the pump as the amount of the liquid stored in the cylindrical container is reduced when the liquid is discharged from the cylindrical container by the pump. The piston has a slanted surface facing the pump for contact with the liquid stored in the cylindrical container, the slanted surface being inclined progressively toward the second axial end. The piston also has a cylindrical surface defining a communication hole defined axially therethrough and having an inner end opening at the slanted surface. The communication hole provides communication between the interior and the exterior of the cylindrical container. A cap comprises a cap body inserted in the communication hole and a flange closes an outer end of the communication hole. At least either one of the cap body and the cylindrical surface has at least one axial groove. Air bubbles which may have been trapped in the container when the liquid is charged into the container move along slanted surface into the communication hole and then is escaped from the container through the groove.
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