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Solenoid Valve Selection

A Guide To Selecting The Right Solenoid Valve

Oil and gas firms are so important that they frequently provide a considerable portion of national GDP. This remarkable success would not have been possible without the discovery, extraction, refining, transportation, and marketing of end products, all of which are essential to numerous businesses.

As a result, it is vital to take certain steps to protect this crucial process, such as a regular maintenance schedule, dual routine checks, and the expedited replacement of some essential components such as solenoid valves.

Now, this raises the question of what a Solenoid Valve is.

What is a Solenoid Valve?

In a hydraulic circuit, a solenoid valve is an electromechanical device that employs an electric current to generate a magnetic field and thus operates a solenoid that controls the opening of a valve.

Notably, an electro-controlled valve is not the same as a solenoid valve. A solenoid valve is made up of a single block and cannot be separated from the system that powers it whereas, an electro-controlled valve is powered by an electrical system that can be separated from the valve body.

The Primary Components of a Solenoid Valve

It is situated on the moveable plunger/pilot or on the valve’s piston assembly and is used to close a valve’s main orifice.The Solenoid and the Valve are the two primary components of a solenoid valve. The solenoid is a cylindrical coil of wire that works as an electromagnet when an electric current flows through it. In contrast, the valve is a control device that directs or controls fluid flow by closing, opening, or partially obstructing different pathways.

In detail, here are some more of the basic components of the solenoid valve:

  • Valve Body: When the solenoid is energized or de-powered, this major portion of the solenoid valve includes ports, seats, and apertures that allow fluids to flow.
  • Solenoid Tube Assembly: This is the magnetically moved guide channel for the movable plunger. The solenoid coil is attached to the outside of the enclosing tube of the valve.
  • Moveable Plunger: A moveable stainless steel coil that is electromagnetically inductive. The solenoid magnetic field attracts it, and it slides within the tube.
  • Plunger Spring: When the movable plunger is powered, this return spring holds it in place and returns it to its original position when de-energized.
  • Seat Seal: It is situated on the moveable plunger/pilot or on the valve’s piston assembly and is used to close a valve’s main orifice.
  • Electromagnet (Solenoid coil): When energized, the electromagnet, which consists of copper windings (solenoid) and a magnetic yoke (armature), generates a magnetic flux that attracts the moving plunger.

Selecting the Right Solenoid Valve

First, you will need to know what kind of media you will be using when picking a solenoid valve. Solenoid valves are designed to function with solid-free media like water, oil, petroleum products, steam, compressed air, or heat transfer fluids. This crucial information allows you to choose the materials for your solenoid valve.

Brass solenoid valves are designed for water, fuel, air, or inert gas. Stainless steel solenoid valves are designed for corrosive liquids or gases, food product liquids, or plastic; primarily in the food and chemical industries.

The material of the seal on the solenoid valve is another consideration when selecting the right solenoid valve. Most solenoid valves are made with Nitrile Rubber, EPDM Rubber, VITON Rubber, PTFE, or Silicone. For reference, here are the different types of seal materials and housing materials along with their intended uses.

 MaterialUse
HousingStainless SteelCorrosive liquids or gases, food product liquids, or plastic.
 BronzeWater, fuel, air, or inert gas.
 316 Stainless SteelHigh-pressure irrigation, steam curing beds, boilers, or High-temperature liquids and gases.
SealsNitrile RubberMost widely used seal material suitable for any use up to 90-degrees Celcius. Inadequate for acidic materials.
 EPDM RubberHigh-temperature uses up to 120-degrees Celsius. Relatively resistant to acids, alkalis, and salts.
 VITON RubberAutomotive and oil exploration. High heat resistance up to 150-degrees Celsius.
 PTFEHighly durable but non-elastic. Ideal for high-temperature, high-pressure applications up to 230-degrees Celsius. Leakage is common when used for gases.

You should use an upstream filter before the solenoid valve to eliminate any possibility of malfunction due to solid particles, also known as impurities.

Two-way or multiple-port solenoid valves are available. They are usually denoted by two digits, one indicating the number of ports and the other indicating the number of positions. A 3/2 solenoid valve, for example, has three ports and two functions.

Most solenoid valves should remain on or off (open or closed); however, others are proportional to the current or supply voltage.

You can choose between normally closed (NC) solenoid valves and normally open (NO) solenoid valves. NC solenoid valves open when supplied by electricity. NO solenoid valves close when powered by electricity. Which option is best depends on your application to maximize the supply time of your solenoid valve.

You can use a bistable solenoid valve with a flap that stays in place even if the power goes out. The key benefit of these solenoid valves is that they are extremely energy efficient.

Moisture is often a problem with solenoid valves. To choose a solenoid valve with an appropriate protection class for the specified environment, you must first assess the external conditions. Alternatively, you can select a lesser protection grade and install the solenoid valve remotely in a less humid climate.

Moreover, because solenoid valves are immediately integrated into a circuit, they are also specified by a nominal diameter (DN). Standards define connector and pipe widths based on the country or geographical area you will utilize and the media you will employ.

Furthermore, other requirements, such as those controlling equipment installed in ATEX (Explosive Atmosphere) zones, may apply to solenoid valves most notably in the energy industry.

Direct-Operated vs. Pilot-Operated Solenoid Valves

The pressure differential between the upstream and downstream medium opens and closes a pilot-operated solenoid valve. You can only use it in one direction as a result. Use the coil to provide the opening or shutting signal in this situation, and it does not require much electrical power. However, this sort of solenoid valve is utilized in high-flow applications to ensure that the pressure differential between the solenoid valve’s input and output is sufficient for it to work.

On the other hand, a direct-operated solenoid valve does not require a pressure differential to operate because the coil acts directly on the diaphragm or valve. Still, it can consume a significant amount of electrical power. This type of solenoid valve is utilized for low flow rates and has a pressure range of 0 bar to the circuit’s maximum pressure.

Conclusion

Solenoid valves get used for various applications, including the control of normal process valves, overpressure protection systems, emergency stop valves, and fluid control in applications like fire system valves. When compared to traditional valves, one of the advantages of solenoid valves is their quick response time.

When choosing the right Solenoid Valve, you can never go wrong with Gould Solenoid Valves. With Over seven decades of building top quality, made in USA Solenoid Valves, Gould Solenoid Valves boasts an experienced team who stands behind all of their valves.

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