What Is a Pressure Reducing Valve and How Does It Work?
Having the right pressure in a fluid system is crucial to safety and efficiency. Industrial pipes, heating systems, or domestic water lines – all can be ruined by excess pressure and be energy-wasteful. That’s where the pressure reducing valve (PRV) enters.
A pressure reducing valve is an important piece of machinery that is employed to control and regulate fluid pressure to a specific downstream level. It is a critical component that avoids over-pressurization and makes system operation smooth.
In this blog, Speciality Valve describes what a pressure reducing valve is, how it works, and where it is commonly used.
What Is a Pressure Reducing Valve?
A pressure reducing valve (PRV) is an automatically controlled valve that decreases high inlet pressure to a constant lower outlet pressure irrespective of changes in upstream pressure or flow rate.
It finds applications in liquid and gas systems, such as water, steam, air, and chemicals. PRVs are self-acting and provide constant downstream pressure without the need for control systems or external power.
How Does a Pressure Reducing Valve Work?
The operation of a PRV is one of forces balance: inlet pressure is opposed by a spring-loaded piston or diaphragm. When the outlet pressure decreases, the valve opens to provide greater flow. When the pressure equals the set value, the valve closes slightly to throttle the flow.
Basic Components:
- Inlet and outlet ports
- Adjusting screw (sets desired pressure)
- Spring and diaphragm/piston assembly
- Valve seat and disc (regulates flow)
Working Process:
- High-pressure inlet fluid is supplied to the valve.
- The spring is pre-set to a fixed downstream pressure.
- With increasing downstream pressure, it displaces the diaphragm or piston.
- Once the equilibrium is established, the valve modulates to keep the set pressure.
- Manual intervention in providing constant pressure is prevented by automatic modulation.
Pressure Reducing Valve Types
PRVs come in many types, each appropriate for particular media and pressures.
1. Direct Acting Pressure Reducing Valve
It utilizes spring and diaphragm to reduce the downstream pressure directly. It is pressure-sensing and suitable for small systems.
Applications:
- Domestic water supply
- Small industrial plant equipment
Advantages:
- Simple design
- Rapid action
- Compact size
2. Pilot-Operated Pressure Reducing Valve
It uses pilot valve to sense the downstream pressure and actuates the main valve. It provides more precise control and greater flow capacity than direct-acting types.
Applications:
- Steam piping
- Large industrial and HVAC systems
- Process plants
Advantages:
- High precision
- Can handle large pressure drops
- Constant performance under varying flow
Differences: Direct Acting vs. Pilot Operated PRV
| Feature | Direct Acting PRV | Pilot Operated PRV |
| Operation Method | Spring & diaphragm directly control valve | Pilot valve controls the main valve |
| Accuracy | Moderate | High |
| Response Time | Fast | Slower but more stable |
| Flow Capacity | Low to medium | Medium to high |
| Complexity | Simple | More complex |
| Maintenance | Easy | Requires skilled handling |
Applications of Pressure Reducing Valves
Pressure reducing valves find application in a variety of industries and systems, wherever accurate pressure control is needed.
Water Supply Systems:
- Domestic plumbing
- Commercial buildings
- Irrigation systems
Function: To lower incoming mains water pressure to a safe level for domestic or commercial use.
Steam Systems:
- Power generation plants
- Sterilizers
- Steam heaters
Purpose: To provide constant steam pressure for effective heat transfer and to avoid steam hammer.
Compressed Air Systems:
- Pneumatic tools
- Industrial automation
Purpose: To provide steady air pressure to tools and actuators, without pressure spikes.
Chemical and Process Industries:
- Reactors
- Tank pressure control
- Mixing and dosing systems
Purpose: To provide precise pressure conditions for safety and product consistency.
Pressure Reducing Valve Advantages
- Avoids equipment over-pressurization
- Saves energy
- Enhances system performance and consistency
- Reduces manual pressure adjustment requirement
- Improves safety and minimizes risk of system failure
Indications of a Failed Pressure Reducing Valve
A faulty PRV can lead to system imbalance and malfunction. Watch out for these signs:
- Unstable or varying downstream pressure
- Dripping or leakage at the valve
- Inability to achieve pressure reduction when adjusted
- Noise or vibration when in operation
- Regular inspection and maintenance are essential in making PRVs function effectively in the long run.
PRV Maintenance Tips
- Inspect for leaks at seals and connections
- Inspect valve response to pressure change from time to time.
- Clean internal parts to eliminate sediment and scale.
- Replace diaphragms or springs when worn.
- Calibrate pressure setting to give accurate reading.
Why Speciality Valve?
Speciality Valve is a reliable international manufacturer and distributor of high-performance Pressure Reducing Valves for industrial and commercial use.
Why industries prefer us:
- High-Quality Materials – Stainless steel, bronze, and cast iron valves manufactured to international standards
- Custom Solutions – We create PRVs according to individual pressure profiles and flow conditions
- Large Inventory – Ready-to-ship products for emergency needs
- Expert Support – In-house engineers to assist selection and system integration
- Worldwide Presence – Providing PRVs to customers in Europe, the Middle East, Asia, and the Americas
- After-Sales Support – Maintenance kits and support 24/7
Conclusion:
Pressure reducing valves are an essential part of fluid systems today. From a household water system to a modern industrial steam facility, PRVs ensure safety, reliability, and efficiency through regulation of downstream pressure to a predetermined level.
By understanding the operation principle, models, and application, users can choose the best valve for his or her system requirement. Speciality Valve designs and provides precise PRVs to work efficiently in different industries, pressures, and forms of media. Our valve is precision-made, long-lasting, and non-clogging. Need the best pressure-reducing valve for your system? Contact Speciality Valve today for expert advice and sound solutions.
