Issues regarding different requirements for valve design in power-loss and air-loss conditions
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There is a valve that needs to be opened in the event of a power loss and closed in the event of a loss of air pressure. How is this achieved? Why is such a design required?
You don’t need to think about this issue, right? Just hand it over to the valve manufacturer
Let’s not discuss why such design requirements exist for now; the issue you mentioned of turning it off when power is cut and turning it off when air supply is stopped can indeed be addressed； Air-off mode: This means that the valve body operates in a spring-driven off mode, with air enabling its operation ； Power-off open: It means that after power is cut off, the solenoid valve body, driven by the spring, opens the air path leading to the pneumatic valve, thereby achieving opening in the absence of power. It can be achieved. Just tell the manufacturer your requirements, and they will meet them.
For pneumatic valves, it’s completely fine for them to open when power is cut off and to close when air supply is stopped. If you’re interested, feel free to contact me privately; I work in a valve manufacturing factory. As for why it is designed this way, it is necessary to take into account factors such as the processes in the production area, power supply, and the supply of instrument air; focusing solely on design aspects would be somewhat one-sided!
In either case, the ultimate goal is to ensure production safety. But here, the fault is either fully on or fully off – how can process safety be ensured? It seems like a contradictory thing; in fact, I personally think it’s a design flaw.
The last edit to this post was made by feng*aosa on 2019-9-25 at 18:21; setting the electrical valve actuator to reverse operation (changing its direction of action) will achieve this functionality； (Note: At this time, the reverse action of the control system should be applied once more in the reverse direction.) This setting is often used when the device still retains a certain degree of controllability even in the event of a gas supply interruption (or power outage).
Power and gas isolation is primarily aimed at ensuring safety in the process
For this air circuit design, you can turn to me. .
There is a valve that needs to be opened in the event of a power loss and closed in the event of a loss of air pressure. How is this achieved? Why is such a design required? There are various ways to achieve this. Taking a pneumatic switch-type butterfly valve as an example, if it originally uses a single-acting normally closed cylinder, it remains closed when there is no air supply. The simplest way is to rotate the valve disc 90° with no load applied; there are many methods available, depending on the specific circumstances.
Power and gas cut off. The location of the valve failure is the location where air is lost