FAQ - Fluid Control Division | Parker US

What is a solenoid valve?


A solenoid valve is a specific type of valve that uses an electromagnetic solenoid to control the flow of the fluid. A solenoid is basically a coil of wire that carries an electric current. When the current passes through the coil, it creates a magnetic field. The solenoid valve consists of two main parts: a coil and a valve body. The coil is wrapped around a hollow tube, and inside this tube, there is a plunger or a piston. The valve body has an opening or passage that allows the fluid to flow through. When the solenoid valve is not energized (no electric current passing through the coil), the plunger or piston rests on a small hole in the valve body, blocking the flow of the fluid. This is called the closed position of the valve.

Now, when the solenoid valve is energized (electric current passing through the coil), the coil creates a magnetic field. This magnetic field attracts the plunger or piston, pulling it up and away from the small hole in the valve body. As a result, the fluid can now pass through the valve body and flow freely. This is called the open position of the valve. In simple terms, a solenoid valve is like a switch for the flow of fluid. When you turn on the switch (by sending an electric current through the coil), the valve opens, allowing the fluid to flow. When you turn off the switch (by stopping the electric current), the valve closes, blocking the fluid from flowing.

So, a solenoid valve is a special type of valve that uses electricity to control the flow of fluid. It can be found in various applications, such as controlling water flow in irrigation systems, gas flow in heating systems, or even in automatic faucets.

In summary, a solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid coil.

  • A valve is an electrical tap
  • It could have one inlet
  • It could have from 1 to 4 outlets
  • Each inlet/outlet is called a "way"
  • We talk then about 2 way valves, 3 way valves, 4 way… etc

 

What problem does a solenoid valve solve?
 

Imagine you have a water hose and you want to turn the water on and off without touching it. A solenoid valve can do that for you! The solenoid is like a little electromagnet that can create a magnetic field when electricity passes through it. When the solenoid is energized (turned on), it pulls a plunger or a disc inside the valve body, allowing the liquid or gas to flow through the pipe. When the solenoid is de-energized (turned off), the plunger or disc is pushed back by a spring, stopping the flow.

To make it even simpler, think of a solenoid valve as a switch for water or air. When you press the switch (energize the solenoid), the valve opens and the water or air can flow. When you release the switch (de-energize the solenoid), the valve closes and the flow stops.

Solenoid valves are commonly used in many everyday objects and systems. For example, they are often found in washing machines to control the flow of water, in sprinkler systems to control the flow of irrigation water, and in car engines to control the flow of fuel or air. They are also used in industrial processes, such as controlling the flow of chemicals in factories.

In summary, a solenoid valve is a device that uses an electromagnet to control the flow of liquids or gases by opening or closing a valve. It is like a switch that can turn the flow on and off.

 

What is a solenoid valve constitued of?

A solenoid valve is made up of three parts, the solenoid, the pilot and, the valve body.

The body is the main part of the solenoid valve with the ports, seats and orifice passages. In almost all Parker products the bodies are made of brass stampings, while other materials such as below are used in some special versions.

  • Stainless steel (303 – 304 – 316…)
  • Aluminum
  • Other

The coil can be different:

  • Standard DIN Coil
  • Standard wired connection coil
  • ATEX coil

 

What is a pole piece?

This acts as a stop for the moveable plunger (=MP) and it is used to shield the magnetic flow. (Usually made of magnetic stainless steel).

 

What types of seal materials are offered on Parker's solendoid valves?

  • NBR (nitrile butadene rubber) - Synthetic elastomer of standard quality for neutral fluids, such as air, water and oils with working temperatures from -10°C to +90°C.
  • CR (chloroprene) - Synthetic elastomer particularly suitable for water, mineral oils, refrigerants, with working temperatures from -30°C to +90°C.
  • EPDM (ethylene propylene) - Synthetic elastomer suitable for hot water and steam with working temperatures from -10°C to +140°C.
  • FKM (Viton) - Fluorinated elastomer suitable for oils, fuel gases, petrols and solvents. Working temperatures from -10°C to +140°C.
  • Ruby - Synthetic corundum (hard stone) with high hardness values and total inertia for all types of fluids. Working temperatures from -40°C to +180°C.
  • PTFE (Teflon) - Plastic material without springback and inert to most fluids, including refrigerants. Working temperatures from -40°C to +180°C. In the case of “Teflon diaphragm ”, this refers to a glass fiber fabric between two layers of PTFE.
  • PTFE with filler (Rulon) - Plastic material with coloured mineral fillers, without springback, inert to most fluids, including refrigerants. Working temperature from -40°C to +180°C. More resistant than virgin PTFE to compression and wear.

 

What is water / fluid hammer?

Water hammer (or, more generally, fluid hammer) is a pressure surge or wave resulting when a fluid in motion is forced to stop. This commonly occurs when a valve is closed suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe. It may also be known as hydraulic shock. This pressure wave can cause major problems, from noise and vibration to pipe collapse.

In the context of a solenoid valve,  what is an intrinsically safe system?

An intrinsically safe system is most often an assembly of approved intrinsically safe apparatus, associated apparatus, and interconnecting cables. Approved I.S. apparatus are devices are incapable, during normal operation or under fault conditions, of causing explosive atmospheres to ignite by spark or thermal effect. Explosive atmospheres are mixtures of flammable or combustible material in air in ignitable concentrations.

Solenoid valves are examples of I.S. apparatus and must be approved for use in specific hazardous (classified) locations. Associated apparatus, such as safety barriers, are devices which affect the energy in the I.S. circuit and are relied upon to maintain intrinsic safety. When related to solenoid valves, intrinsic safety means that the coil’s current draw and resulting temperature is held to such a low level (by an approved safety barrier) that the valve no longer has the capability of igniting a mixture of flammable or combustible material, either during normal operation or under fault conditions.