20150377231 | PUMP FOR REMOVING LIQUIDS FROM VESSELS UNDER VACUUM - A pump moves fluid by means of a piston reciprocating inside a cylinder. Fluid enters the cylinder through an inlet valve that passes through the cylinder head, and has an enlarged surface inside the cylinder, which seals against the cylinder head. This valve is normally held closed by a spring. As the piston advances, fluid is forced out of the cylinder through a passage in the cylinder head and a check valve. A rod is affixed to the piston and passes through the inlet valve. As the piston retracts, the rod slides through the inlet valve, until a stop, affixed to the rod, encounters the stem of the inlet valve. The spring holding the valve closed is overcome and the valve opens as the piston and rod move farther, until the piston is in its fully retracted position. Fluid enters the cylinder until the piston again begins to advance. The stop ceases to push the inlet valve open, and the spring again holds it closed. | 12-31-2015 |