| 摘要 |
<p>For using dispensers of the type in which a first can of semi-fluid hand cleaner or similar viscous substance is filled into a dispenser sleeve, and then a second can of the substance is inverted and applied telescopingly over the sleeve, accumulation of the substance in the internal vent tube of a large size dispenser may make it difficult to remove and replace cans, and may interfere with air inflow necessary for dispensing. In the present invention, air inflow, to permit removal of such a first can, is assured by a pull-down piston in the vent tube to drive any clogging substance out through the nozzle passage. On applying a second full can over the sleeve, the cleaned tube permits easy expulsion of intervening air. Even while the tube is clogged, dispensing may proceed normally; a groove leading downward on the outer side of the sleeve permits continuing inflow of air.</p> |
