A valve for fluids employs two telescoping parts which cooperate with one another to block fluid flow when pulled partially apart and open a flow path therethrough when pushed together. A plunger component, having a central bore, a closed off end and perforated walls, is slidingly and sealingly received...http://www.google.de/patents/US5336174?utm_source=gb-gplus-sharePatent US5336174 - Flow control valve
