When there is no pressure signal input, the valve is closed; when there is a pressure signal, the valve starts to open, and the larger the input signal, the larger the valve opening, this kind of film regulating valve is called air-opening film regulating valve in small air spearation unit.
When there is no pressure signal input, the valve is fully open, and when there is a pressure signal input, the valve starts to close; the larger the input signal, the smaller the valve opening; when the input signal reaches the maximum, the valve is fully closed, this film valve is called gas-closed film adjustment valve.
In practice, the choice of gas open, gas closed mainly from the production of safety requirements to consider, the regulating valve is closed to the production of the smallest hazard, the choice of gas open type. If the valve is open when the least harmful, to choose the gas-closed type. Liquid-air-liquid nitrogen control valve, turbine expansion machine in front of the emergency shut-off valve are gas-open type. When the gas is cut off, the valve is in a closed state; turbomachine anti-surge valve in the gas cut off, the valve must be open, using gas-closed type. The venting valve on the oxygen storage tank and the nitrogen venting valve on the upper tower are gas-closed, so that in the event of a failure, power and gas outages can be bled to ensure safety.
In the design process, Dear Air has designed all aspects of technology, piping and valves to meet the international standards of the industry to ensure high quality requirements for small air spearation unit, large air spearation unit and liquid air spearation plant installation.
