| 摘要 |
A solenoid valve 1 for controlling evaporation of liquid is opened and closed based on flow demand and pressure changes upstream and downstream of the valve 1. A control means (not shown) is connected to flow demand means (not shown), a sensor 5 for sensing pressure in a liquid line 4 upstream of valve 1, and a sensor 2 provided in a flashing off chamber 3 for sensing pressure downstream of the valve. The valve is opened when the pressure in flashing-off chamber 3 is less than the pressure sensed in liquid line 4, and is closed when sensor 5 detects an increase in the liquid line pressure whilst the valve is open. Flow modifying divergences 9 may be provided downstream of the flashing off chamber 3. Preferably, the valve is used to controllably allow a near-boiling, just-condensed liquid to flash off to a lower pressure, highly saturated vapour state in the flashing off chamber 3, with the vapour being passed to an expansion engine (2, fig. 2) such that work derived through expansion of the vapour may be used to drive a compressor (4, fig. 2). Operation of the valve may be controlled by a computer (not shown). |
