| 摘要 |
A flow control device is provided for controlling the pressure of a controlled fluid in a secondary line as a function of the pressure of a controlling gas in a primary line. The device includes a pressure regulator having a housing divided into upper and lower chambers by a diaphragm. A pressure divider is connected to the upper chamber in such manner that the pressure in the upper chamber is proportional to the pressure of the controlling gas. The secondary line is connected to the lower chamber. Fluid communication between an upstream portion of the secondary line and the lower chamber is controlled by a valve operatively associated with the diaphragm. When the pressure in the upper chamber is less than a predetermined pressure, the valve blocks fluid communication between the upstream portion of the secondary line and the lower chamber. After the pressure of the controlling fluid exceeds a predetermined pressure, the pressure in the upper chamber, which is a function of the pressure of the controlling gas, moves the diaphragm into a position in which the valve associated with the diaphragm permits fluid communication between the lower chamber and the secondary line. A fixed pressure loss is provided in the device so that there is a difference in pressure changes between the controlling gas compared to the controlled fluid.
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