| 摘要 |
The invention contemplates a pressurized container for viscous foods or other viscous products in which the body of the piston includes, adjacent the head end, a flexible circumferential band which lightly contacts or is expandable in the presence of loading pressure exerted by propellant gas. The band thus develops light sealing contact with the interior wall surface of the container, and such contact effectively isolates unexpelled product from the gas-pressure side of the piston, regardless of the extent to which product has been expelled. The piston further includes circumferentially continuous tail structure which is connected to and axially spaced from the expandable band and which serves to stabilize the piston against malfunction in the course of its single product-expelling stroke.
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