Let’s begin our guide to industrial valves.
Industrial valves are essential components in any system involving the transport, control or containment of pressurised fluids.
This technical guide explores the most common types of valves used in industry —including pressure reducing valves and relief valves— explaining their function, features and typical applications.
We also introduce the valve models developed by Valfonta, a manufacturer with over 50 years of experience, and our technical recommendations for various industrial scenarios.
This guide is aimed at engineers, plant managers, maintenance professionals and process technicians looking for a clear and practical reference when selecting industrial valves.
What is an industrial valve and what does it do?
An industrial valve is a mechanical device designed to control the flow of a fluid (liquid, gas or steam) through a piping system.
Depending on its design and operating principle, it may perform one or more of the following key functions:
- Regulate pressure in the system (upstream or downstream).
- Open or close the flow path (manually or automatically).
- Divert flow between different pipelines (e.g. three-way valves).
- Release excess pressure to protect equipment (relief/safety function).
Valves are critical to ensure:
- Safe operation of the system and equipment.
- Stable and continuous process control.
- Energy efficiency and longer system lifespan.
They can be operated manually or automatically via pneumatic, electric or hydraulic actuators, depending on the level of control required.
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Pressure reducing valves
Pressure reducing valves (PRVs) are designed to maintain a constant outlet pressure regardless of fluctuations in inlet pressure. They are commonly used in systems that require protection for sensitive equipment or pressure adjustments between sections of the same installation.
How do they work?
These valves operate automatically and proportionally: when the inlet pressure exceeds the setpoint, a spring-loaded diaphragm or piston reduces the flow opening to keep the outlet pressure stable.
They are self-acting —they do not require any external power supply— and operate via a balance of forces between the spring and the fluid pressure.
When should you use a PRV?
- When the main line pressure is higher than what is needed downstream.
- To protect pipelines, heat exchangers or instrumentation from overpressure.
- In systems with frequent pressure changes but where a stable outlet is required.
- To improve safety and energy efficiency.
Common applications:
- Steam systems (to reduce pressure before entering heat exchangers).
- Potable water and industrial cooling networks.
- Compressed gas systems or technical fluids in labs.
Valfonta’s pressure reducing valve range
At Valfonta, we offer a wide selection of pressure reducing valves tailored to different industrial demands. Here are the main product series:
Some of our most requested valves:
M Series – M1 and M2 valves
Self-acting pressure regulators that are robust, reliable and versatile.
They feature a guided plug and a reinforced diaphragm pressure chamber. Ideal for continuous operation with minimal maintenance.
- Pressure range: from 0.1 to 15 barg
- Temperature: up to 220 °C with EPDM + PTFE diaphragm
- Materials: stainless steel, carbon steel, ductile iron
Suitable for: steam, compressed air, technical gases, industrial water
PRV Series – PRV20, PRV30, PRV44, PRV45
Compact, balanced self-operated valves with a modern design and high control accuracy.
- Pressure range: 0.01 to 10 barg
- Maximum inlet pressure: up to 25 bar
- Connections: BSP/NPT threaded, DIN or ANSI flanged
- Body materials: stainless steel AISI 316L or industrial bronze
Typical uses: laboratories, compressed air, nitrogen, sanitary systems, neutral gases
VD Model
A compact, self-operated pressure reducing valve designed specifically for gas and steam applications.
- Pressure range: 0.01 to 8 barg
- Design: compact, with pneumatic actuator on top
- Materials: stainless steel or bronze, depending on use
- Installation: easy integration in horizontal pipelines
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Pressure relief valves
Pressure relief valves —also referred to as excess pressure valves— are designed to release pressure automatically when it exceeds a set limit. Their primary function is to protect the installation against sudden pressure spikes that could damage equipment or compromise system safety.
Unlike pressure reducing valves, relief valves do not regulate continuously; they remain closed until the set point is reached.
How do they work?
When upstream pressure exceeds the set value, the valve opens progressively to release excess fluid. Once pressure returns to a safe level, the spring mechanism closes the valve again.
Relief valves should not be confused with safety valves, which typically open more abruptly and are intended for emergency discharge.
When should you install a relief valve?
- To protect tanks, heat exchangers, pumps or boilers from overpressure.
- In systems subject to transient pressure peaks (e.g. valve closures, pump start-ups).
- As a safety backup to pressure regulators or control valves.
Common applications:
- Steam and compressed air lines
- Sanitary and gas installations
- Chemical and pharmaceutical facilities
Valfonta’s relief valve range
S1
- Self-acting, no external power required
- Suitable for steam, air, gases and liquids
- Pressure range: 0.1 to 15 barg
- Body materials: stainless steel, carbon steel, ductile iron
S2
- High sensitivity and accurate response
- Adjustable range: 0.02 to 10 barg
- Connections: DIN/ANSI flanges or BSP/NPT threads
- Ideal for systems with fluctuating pressure
S3
- Guided plug with soft or metal sealing
- Adjustable up to 20 barg
- High-temperature resistant materials (up to 220 °C)
- Recommended for steam, aggressive fluids and industrial gases
PRV53
- Compact valve for neutral gases and liquids
- Max pressure: 10 barg
- Stainless steel AISI 316L body
- Available with threaded or flanged connections
PRV54
- High thermal resistance (up to 210 °C)
- Suitable for steam, gases, and superheated water
- Bellows-balanced, ideal for continuous service
PRV55
- Robust, full stainless-steel construction
- Setpoint range: 0.01 to 8 barg
- Easy to adjust, minimal maintenance
- Recommended for sanitary and laboratory applications
Comparative table: types of industrial valves
| Valve type | Main function | Typical applications | Recommended models |
|---|---|---|---|
| Pressure reducing valve | Keep outlet pressure constant | Steam, compressed air, industrial water | M1, M2, PRV20, PRV44, VD |
| Pressure relief valve | Release pressure above set point | Boilers, pressurised systems, steam, gas | S1, S2, S3, PRV53, PRV54, PRV55 |
| Control valve | Adjust pressure, flow or temperature | Automated processes, industrial fluid control | C1 |
How to choose the right valve for your system
Selecting the correct valve for your installation involves assessing several technical and operational factors that directly affect performance, safety and system longevity:
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Understanding the differences between pressure reducing and relief valves is key to ensuring safe and efficient fluid system operation.
At Valfonta, we provide a full range of technically advanced valve solutions tailored to your installation’s specific needs.
Our engineering team is also available to offer personalised support to help you determine the most suitable model for your conditions.
Need advice? Contact us or call us directly — we’ll be glad to help you optimise your system.
