| 摘要 |
A liquid measuring and dispensing device has a central flow tube sealingly surrounded by a measuring chamber slidable relative to the flow tube so as to bring respective ports in the flow tube and the chamber into register for filling and emptying the chamber through the two ends of the flow tube which form inflow and outflow ducts respectfully, and a shuttle valve within the flow tube and between the ducts and movable with the chamber to isolate the portion of the flow tube between its ports and thereby prevent direct flow along the flow tube between the ducts, the outside diameter of the flow tube surrounding the inlet duct being reduced in diameter so as to provide an air vent for the chamber during emptying. |
