Pressure reducing valves (PRVs) are essential components in fluid and gas systems across a wide range of industries. They provide reliable control over system pressures, helping protect equipment, improve efficiency, and ensure safe operation. Whether you’re designing a new installation or maintaining existing infrastructure, understanding how PRVs work and where they’re used is key to optimising system performance.
This guide explores the purpose, operation, types, applications, and benefits of pressure reducing valves, providing a complete overview for professionals and system operators alike.
What is a Pressure Reducing Valve?
A pressure reducing valve is a self-regulating control device designed to reduce a higher inlet pressure to a lower, stable outlet pressure. Unlike manual valves, PRVs operate automatically, sensing changes in downstream pressure and adjusting their opening to maintain consistent flow conditions.
PRVs are widely used in water, steam, compressed air, and gas systems, where excessive pressure can damage pipes, fittings, and sensitive equipment. By ensuring pressure stability, they not only protect systems but also contribute to energy savings and operational reliability.
VALSTEAM ADCA Pressure Reducing Valves
The ADCA P7 series is a direct-acting, spring-loaded diaphragm sensing pressure reducing valve designed for use with steam, compressed air, and other gases. Its compact stainless-steel construction and threaded connections make it ideal for small to medium systems requiring precise pressure control and reliability in demanding environments.
The ADCA P20D series offers similar performance with the addition of a balanced plug design for improved stability under varying inlet pressures. Suitable for compressed air and other clean gases, the P20D is built in stainless steel and available with threaded or flanged connections, making it a versatile solution for industrial and process applications.
VALSTEAM ADCA | P7 PRESSURE REDUCING VALVES
VALSTEAM ADCA | P20D PRESSURE REDUCING VALVES
How Does a Pressure Reducing Valve Work?
At the heart of every PRV is a spring-loaded diaphragm or piston that senses the downstream pressure. The operation is based on a simple but effective balancing act between the spring force and the pressure exerted by the fluid or gas:
Normal Operation: When the downstream pressure drops below the setpoint, the spring pushes the diaphragm or piston down, opening the valve wider and allowing more fluid to pass through.
Pressure Increase: As downstream pressure rises above the setpoint, it pushes against the diaphragm or piston, overcoming the spring force and causing the valve to close slightly, thereby restricting flow.
This continuous modulation keeps the outlet pressure steady, regardless of variations in upstream supply or downstream demand.
In larger systems, pilot-operated PRVs are often used. These use a smaller pilot valve to control the main valve’s opening, allowing for more precise regulation in high-capacity networks.
Types of Pressure Reducing Valves
There are several types of PRVs, each suited to specific applications:
Direct-Acting PRVs
Compact and simple, these valves use a spring and diaphragm mechanism for immediate response. They are ideal for smaller systems with lower flow rates and where space is limited.
Pilot-Operated PRVs
These valves use an auxiliary pilot valve to control the main valve, allowing accurate pressure regulation even at high flow rates. They are commonly found in large-scale municipal water systems and industrial steam networks.
Balanced Plug PRVs
Designed for applications where inlet pressure may fluctuate widely, balanced plug designs prevent changes in upstream pressure from affecting the outlet setpoint.
Applications of Pressure Reducing Valves
Pressure reducing valves are used wherever controlled pressure is critical for system safety and efficiency. Typical applications include:
Municipal Water Mains: Reducing high supply pressures to safe levels for domestic and commercial distribution.
Steam Systems: Ensuring consistent steam pressure for heating and process applications.
Compressed Air Networks: Delivering air at appropriate pressures to tools and machinery.
Irrigation Systems: Protecting sprinkler systems from overpressure and ensuring even water distribution.
Pharmaceutical and Food Industries: Providing precision control in hygienic environments where pressure consistency is essential.
Benefits of Pressure Reducing Valves
Using PRVs in your system offers a wide range of advantages:
Equipment Protection: Prevents overpressure damage to downstream components such as pumps, heat exchangers, and appliances.
Operational Efficiency: Maintains optimal pressures, reducing energy waste and improving overall system performance.
Safety Compliance: Meets regulatory standards by ensuring systems operate within specified pressure limits.
Lower Maintenance Costs: Reduces wear and tear on pipework and fittings, extending their service life.
System Stability: Provides consistent performance even in systems with varying demand.
Selecting the Right Pressure Reducing Valve
Choosing the right PRV for your application requires consideration of several factors:
System Pressure and Flow Rates: Determine the maximum and minimum operating pressures and flow requirements.
Media Type: Consider the properties of the fluid or gas (e.g., water, steam, air, chemicals).
Material Compatibility: Select stainless steel, carbon steel, or other materials based on corrosion resistance and durability.
Connection Type: Threaded, flanged, or specialised connections may be required depending on the system design.
At ISIS Fluid Control, our team can help you select the most suitable valve from our extensive range of pressure reducing valves, tailored to meet your specific system requirements.
Maintaining Pressure Reducing Valves
To ensure long-term performance, regular inspection and maintenance of PRVs is essential:
Visual Checks: Look for leaks, corrosion, or damage to valve housings and discharge pipes.
Functional Testing: Test the valve periodically to confirm it opens and closes correctly.
Servicing: Replace worn diaphragms, seals, or springs as recommended by the manufacturer.
In industrial settings, compliance with UK Pressure Systems Safety Regulations (PSSR) often requires routine testing and certification.
Why Choose ISIS Fluid Control for Pressure Reducing Valves?
At ISIS Fluid Control, we pride ourselves on supplying high-quality PRVs for a wide range of industries. Our valves combine robust construction, precision engineering, and reliable performance to meet the demands of modern systems.
With our purpose-built workshop and highly skilled team of engineers, we can provide tailored solutions to support your operations. Whether you require a compact direct-acting valve or a large pilot-operated unit, we offer the expertise and product range to meet your needs.
Explore Our Range of Pressure Reducing Valves
Browse our selection of pressure reducing valves to find the ideal solution for your application. For expert advice or assistance with selecting the right valve, contact our team today and let us help you maintain system efficiency and safety.