Shutting off and bypassing of self-regulating valves
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The PID for the engineering design provided by the three membrane filtration companies specifies that the compressed air inlet to the pressurized dissolved air tank (used to inflate corrosive brine) should have its pressure reduced, from ~0.7 MPa to 0.25 MPa. With a pipe diameter of DN15~20, the control valve solutions offered by the three membrane filtration companies are as follows: 1) ordinary control valve + upstream and downstream shut-off valves + bypass; 2) self-acting control valve + upstream and downstream shut-off valves + bypass; 3) a separate self-acting control valve. There are three options in total. I’m really confused – which one is more economical, safe, and reasonable?
The second is the commonly used configuration, with front and rear shut-off valves used for single-channel testing of the pressure regulator as well as for repairing faults in the pressure regulator； The bypass is used for the automatic switching of the pressure regulation circuit (achieved through different pressure settings for the main and auxiliary circuits) ； In addition, a built-in shut-off valve in the regulator or a relief valve at the regulator’s outlet is required to provide overpressure protection for the system ；
Agree with the view on the second floor. The third option is not entirely unfeasible either; if the pressure regulating valve is of reliable quality, this approach can indeed be used. However, there is a certain risk: valve failures can affect production during maintenance. If the impact is minimal, this option can be chosen.
The second option is recommended, as it is relatively safer and easier to control~~~
If the process described by the original poster involves no hazardous chemicals or flammable gases, and there are no issues related to pressure release, then the third option is recommended: choose a pressure regulator of reliable quality, but it is necessary to install a bypass line
Today’s self-acting pressure control valves are highly mature and reliable; they are the simplest and most economical option!