Can a pressure relief valve reduce static pressure?

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The basic working principle of a pressure reducing valve is to reduce water pressure by creating local resistance to the flow of water within the valve’s flow channels. The range of pressure reduction is automatically adjusted by the pressure difference between the inlet and outlet waters on either side of the diaphragm or piston that connects the valve disc, thereby reducing both dynamic pressure (when water is flowing) and static pressure (when the flow rate is zero). A pressure reducing valve can help maintain a constant pressure; for example, if the actual operating pressure is 0.8–0.65 MPa, can the pressure remain stable at 0.8–0.65 MPa even after the valve is closed? Is this possible? A conventional pressure reducing valve can only reduce pressure but not maintain a constant pressure; whereas a self-acting pressure reducing valve is a type of automatic control valve that combines pressure reduction and pressure stabilization, ensuring that the pressure downstream of the valve remains constant regardless of fluctuations in the pressure upstream. A pressure reducing valve can stabilize the pressure downstream; does your client mean that the pressure upstream needs to be stabilized in the absence of a pressure reducing valve? A relief valve/safety valve can serve a similar function. It is feasible to assume that gas is supplied from a source at 1 Mpa, thereby keeping the pressure after the pressure regulator stable between 0.65 and 0.8 Mpa. The pressure relief valve contains an elastic control spool to regulate the opening degree, and the elasticity can be set. The interaction between the pressure difference between the upstream and downstream sides and the preset elasticity controls the degree of opening of the valve core. Assuming a value of 0.7 Mpa is set, when the pressure downstream approaches 0.7 Mpa, the valve core opens less and less until it closes; when the pressure is below 0.7 Mpa, the degree of opening increases, enabling automatic adjustment. This is the ideal situation; in reality, the way any device functions is based on physical laws – it doesn’t act according to whatever you want it to do. If a pressure relief valve has stable and accurate performance, it can provide a stable pressure difference between the upstream and downstream sides, rather than a constant downstream pressure. If the pressure of the upstream gas supply is stable, then the downstream pressure can be maintained at a stable level. If the upstream supply is via gas cylinders, the compressed gas stored in these 40L cylinders will continuously lose pressure from 15 Mpa; the pressure regulator installed cannot maintain a stable pressure downstream, and its capacity to supply gas is also limited. If the pressure downstream drops suddenly and rapidly, the regulator may not be able to replenish the gas fast enough, resulting in an unstable pressure. The term commonly used, “reduced static pressure,” is technically inaccurate, as the word “reduced” implies an energy loss, whereas there is no energy loss in the aforementioned stationary state. Therefore, in practice, the reduction of static pressure by a pressure reducing valve is achieved by using the principle of hydraulic balance to keep the valve closed, thereby cutting off communication between the upstream and downstream sections and maintaining (or controlling) a lower, stable downstream pressure level. The dynamic pressure pressure reduction principle involves placing the pressure reducing valve in a state of a flow element with energy loss. For pressure reducing valves, this gap is automatically adjustable, unlike pressure reducing orifice plates whose orifices remain fixed; this is what makes pressure reducing valves adjustable, and it is also why the pressures before and after the valve should not be set too high when using such valves.