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PRESSURE REDUCING VALVE (PRV)

 PRESSURE REDUCING VALVE (PRV)



A Pressure Reducing Valve (PRV) is a critical component in fluid systems that ensures the downstream pressure remains at a set level, no matter the fluctuation of the incoming pressure. PRVs are used in various industries.


A. Function of Pressure Reducing Valves:


 The primary function of a PRV is to reduce high inlet pressure to a lower, manageable pressure to protect sensitive equipment and maintain efficiency. This ensures that downstream systems, pipes, pumps, and other components do not experience damage from excessive pressure. It is especially crucial in systems where pressure must be kept within a certain range to ensure safety, system performance, and energy efficiency.


B. Working of Pressure Reducing Valves:

 

The PRV operates based on the principle of controlling fluid flow. The inlet pressure pushes against the valve’s diaphragm or piston, which in turn adjusts the valve opening. This adjustment allows the fluid to flow through the valve at a consistent, reduced pressure.


1. Inlet Pressure: When fluid flows into the valve, it applies pressure to a sensing mechanism (like a diaphragm or piston).


2. Pressure Adjustment: The sensing mechanism moves, which opens or closes the valve to allow only the required amount of fluid to pass through. As the inlet pressure increases, the valve compensates by closing further to maintain the downstream pressure. Conversely, if the inlet pressure decreases, the valve opens to allow more flow.


3. Downstream Pressure: The set point for the downstream pressure is pre-determined based on system needs and can be adjusted by turning the spring mechanism or an adjustment screw.


 The PRV maintains this balance to ensure that the downstream system does not experience excessive or insufficient pressure.


C. Components of a Pressure Reducing Valve:


 1. Inlet Port: The inlet is where high-pressure fluid enters the valve. It is usually connected to the upstream system.


 2. Outlet Port: The outlet is where the reduced-pressure fluid exits and flows downstream to the rest of the system.


 3. Diaphragm or Piston: The sensing element inside the valve that responds to pressure changes. It moves in response to the pressure in the system and adjusts the valve opening accordingly.

 

 4. Spring Mechanism: The spring helps in adjusting the set pressure. When the pressure exceeds the preset level, the spring compresses and helps close the valve. Conversely, when pressure drops below the set level, the spring expands, opening the valve to maintain the desired pressure.


 5. Valve Seat and Disc: These components control the flow of fluid through the valve. The valve seat acts as a sealing surface, while the disc moves to block or allow fluid to pass through, controlling the flow.

 

 6. Adjusting Screw or Knob: This is used for manual adjustment of the valve to set the desired downstream pressure. It adjusts the tension of the spring mechanism.

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