What is a Solenoid Valve?

Solenoid valves are among the most widely used components in process control, fluid handling, and automation systems. Their ability to provide precise, repeatable, and remote control over fluid and gas flow makes them essential in industries ranging from oil and gas to pharmaceuticals, food production, and general manufacturing.

At Measure Monitor Control (MMC), we supply a comprehensive range of solenoid valves from trusted manufacturers, designed to meet the most demanding industrial requirements including high-pressure operation, hazardous area certification, and compatibility with aggressive media.

This article explains what solenoid valves are, how they function, the different types available, and what factors to consider when specifying one for your application.

What is a Solenoid Valve?

A solenoid valve is an electromechanically operated valve that uses an electric current to control the movement of a plunger or armature, which opens or closes an orifice to regulate the flow of a fluid (liquid or gas).

  1. At its core, a solenoid valve consists of two main parts:
  2. The solenoid coil a wound copper coil that generates a magnetic field when energised.

The valve body and internal mechanism containing the plunger, spring, seals, and ports that manage flow.

When electrical power is applied to the coil, the generated magnetic field lifts or shifts the plunger against a spring force, changing the valve’s position from closed to open (or vice versa, depending on design).

Because this operation can be achieved quickly, reliably, and remotely, solenoid valves are widely used in automated control systems where flow must respond to electrical signals from sensors or controllers.

Solenoid Valve Configurations

Normally Closed (NC)

The most common configuration. The valve remains closed when de-energised and opens when voltage is applied. Ideal for applications where flow must stop automatically during power loss.

Normally Open (NO)

The valve remains open until energised. Used where maintaining flow is critical and it should only close under control.

Universal or Bi-stable

Some solenoid valves can be configured as either NO or NC, or designed to remain in their last position when power is removed useful in systems where energy saving or fail-safe positioning is required.

Direct-Acting vs Pilot-Operated Valves

Direct-acting solenoid valves use the magnetic force directly to move the plunger and open or close the orifice. These are best suited for low flow rates or low-pressure systems, where precise control is essential and differential pressure is minimal.

Pilot-operated (servo-assisted) valves use system pressure to assist operation. When the solenoid coil is energised, it opens a small pilot port that allows the pressure differential across a diaphragm or piston to actuate the main valve. This design is ideal for higher flow rates and pressures but requires a minimum pressure differential to operate correctly.

MMC supplies both direct-acting and pilot-operated solenoid valves across a wide pressure and flow range, ensuring suitability for simple automation tasks through to demanding process applications.

Key Technical Considerations When Selecting a Solenoid Valve

Choosing the correct solenoid valve for an application requires understanding multiple interacting factors:

1. Media Type

The fluid’s chemical composition, viscosity, and cleanliness determine the choice of valve materials and sealing elastomers. MMC supplies valves in brass, stainless steel, and engineered plastics, with seals in NBR, EPDM, FKM, or PTFE to ensure chemical compatibility.

2. Pressure and Temperature Ratings

Operating pressures may range from vacuum to over 400 bar, and temperature extremes can significantly affect performance. MMC’s product range includes high-pressure and cryogenic solenoid valves suitable for aggressive or extreme environments.

3. Electrical Characteristics

Voltage (AC/DC), power consumption, and enclosure type (IP rating) are critical for compatibility with control systems and site conditions. For hazardous areas, MMC provides solenoid valves certified to ATEX, IECEx, or similar standards for safe use in explosive atmospheres.

4. Response Time and Duty Cycle

High-speed or continuous-duty applications (such as pneumatic actuation or dosing) require coils designed for rapid cycling and thermal stability. MMC offers options optimised for both fast switching and long service life.

5. Port Size and Flow Coefficient (Cv or Kv)

Valve sizing must ensure adequate flow with acceptable pressure drop. MMC’s engineering team can support customers in calculating flow coefficients and specifying the correct orifice size for each system.

Typical Applications

Solenoid valves supplied by MMC are used in:

  • Process automation: controlling air, water, or chemicals in automated plants.
  • Pneumatic systems: actuator control, air distribution, and blow-off operations.
  • Energy and power generation: managing fuel gas, cooling circuits, and safety interlocks.
  • Cryogenics and high-pressure systems: handling liquefied gases and extreme conditions.
  • Hazardous environments: where ATEX-certified solenoids ensure compliance and safety.

Why Choose Measure Monitor Control?

Measure Monitor Control is an independent specialist distributor of valves, measurement, and control solutions for industrial applications. Our technical expertise, product diversity, and commitment to quality make us a trusted partner for engineers seeking reliable process control components.

We work closely with leading global manufacturers to deliver solenoid valves that meet precise engineering and compliance standards. Whether you need a single valve or a complete integrated solution, our team provides application-specific guidance, fast turnaround, and full documentation support.

Not sure which valve or measurement solution is best?
Use our experience to guide you...

For a deeper understanding of which valve or instrument would be best for you please call or email us now so that we can save you time and ensure you can make a truly objective decision for your company.

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+44 (0) 1443 772500 / 02922 780798

Red Dragon Limited T/A
Measure Monitor Control
Unit 15 Abergorki Industrial
Estate
Ynyswen Road
Treorchy
South Wales
CF42 6DL
United Kingdom
EORI: GB791056521000

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