| 摘要 |
<p>A valve unit to be used in a packing machine of the type which manufactures filled and sealed non-returnable packages for dairy products such as milk, yogurt and the like from prefabricated blanks. The packages are filled one at a time by a metering pump and the liquid is fed from the pump to the package via the valve unit. The valve unit includes a check valve and a flexible nozzle which co-operate so as to prevent any after-dripping between pumping strokes. This is achieved in that the check valve with the help of a piston component, after the completed pumping stroke, creates a vacuum in the liquid filled valve unit. This vacuum affects the flexible nozzle so that it closes rapidly and effectively.</p> |
