How does a non relieving regulator maintain constant downstream pressure?
by Julian G
I would have thought that the setting of the poppet would mean that there will be a continuous flow from the upstream to the downstream, and downstream pressure would rise when there is no relieve or bleed. Bill says... Hello Julian. A non-relieving regulator would be selected when the gas that it is controlling cannot be released to atmosphere due to toxicity or flammability, or that it's an expensive product that the user doesn't wish to waste. A regulator will relieve air when the downstream application creates a pressure back-spike in the supply line to the application downstream of the regulator. This raises the pressure in the application and line that has to be relieved to allow that back pressure spike to dissipate to atmosphere. Or, when the pressure in a system has been set at one level, and then it's desired to have the pressure set lower. Downstream pressure that was higher than the new setting, would relieve. Normally, a relieving regulator is placed upstream of the air valve, and the air passing through that valve is already at the correct pressure. That air is commonly used in an air actuator of some sort. The operation of the air valve then allows the compressed air to drive the actuator, and where the air has to exit the actuator to atmosphere, that takes place at the air valve, not the regulator. If a non-relieving regulator is used in an application where there is need to lower the pressure from a higher pressure level, then you are right, the downstream pressure would not vent. To select the right regulator would have to take these issues under consideration. Thanks for writing in. Bill
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