| 摘要 |
<p>A valve for controlling fluid flow having a cavity divided into first and second chambers by a first bellows carrying a plunger which has one end extending into the valve outlet opening at one wall of the first chamber. A second bellows, co-axial with the first bellows, acts between the end of the plunger remote from the opening and a wall of the second chamber and forms a third chamber in communication with fluid at the outside of the opening by way of a longitudinal conduit in the plunger. Inlet fluid is supplied to the second chamber and is supplied to the first chamber by way of a manually operable flow control valve. The plunger position is dependent upon the difference in fluid pressures in the first and second chambers and varies the size of the opening. Fluid in the third chamber counter-balances the pressure of the fluid at the outlet on the end of the plunger thereat.</p> |
