What Are Solenoid Valves and Their 5 Different Types?

When you need to control the flow of a liquid or gas, whether automatically or on/off, you'll need a solenoid valve. To put it another way, a solenoid valve can be used to open or close a circuit, dose products, mix gases or liquids and so on.

The services vary from standard process valves to specific valve control such as overpressure protection systems and emergency stop valves. And fluid control in applications such as fire system valves.

There are many things to learn about solenoid valves. Let’s get into its details.

What is a solenoid valve?

Solenoid valves, also known as solenoids, are devices that convert electrical energy to mechanical energy, causing a magnetic reaction every time an electric current passes through the solenoid's wire. The solenoid activates a gadget when it is pressed into motion. The majority of the time, these devices are utilised to power fluid and hydraulic systems like irrigation controllers.

Solenoids serve a variety of purposes, like starting your car and activating your sprinkler system. A solenoid valve's primary function is to control flow in fluid and air-powered systems and motors. To power some gadgets, these devices turn off, expel or mix fluids.

Solenoid valves have a faster response time than traditional valves. As a result, they're used in the following applications:

• In compressors, the solenoid valve is utilised to discharge the compressor during the startup phase to lower the torque on the engine.
• In agriculture, the fast response time of irrigation solenoid valves saves water in sprinkler systems.
• Double body valves can be used in particular circumstances, such as industrial presses where the failure of the solenoid valve could result in an accident for the operator. These are usually 3/2-way solenoid valves with a double valve system that allows them to compensate for the failure of one of them.
  
  

5 different types of solenoid valves:

1. Direct-acting valves
   
   
   A coil in these solenoids magnetically opens the valve in direct action, shifting the shaft and seat of the valve. The energy produced by the solenoid's magnetic field is used to operate direct-acting solenoid valves. A mechanical spring returns the valve to its original position when the electrical current is disconnected.
   
   
   Direct-acting valves are used to keep a device from accumulating too much pressure.
   
   
2. Pilot-operated valves
   
   
   In pilot-operated valves, the plunger opens the pilot opening and the pressure causes the valve to open and close. Even though pilot-operated valves take less electrical energy to operate, they must maintain full power to remain open, and they function at a slower rate than direct-acting solenoids. Direct-acting valves only require full power while opening the valve since they can maintain their open position even when operating at low power.
   
   
3. Two-way valves
   
   
   They are made up of two ports, one for allowing inflow and the other for cutting it off. In terms of operation, a two-way valve can be categorised as either normally open or normally closed. These valves are extremely adaptable and may be used in a wide range of applications in many industries for easily switching on and off the flow. With a usually open valve, the valve remains open unless the current is applied to close it.
   
   
4. Three-way valves
   
   
   This valve has three ports: one for the valve inlet, one for the outlet, and one for the exhaust. It is used to operate single-acting actuators. They are often used when a control valve's diaphragm operator receives alternate and exhaustive pressure and can be classified as normally closed, normally open or universal for diverting functions depending on the valve condition when the solenoid is energised.
   
   
5. Four-way valves
   
   
   These valves can have four or more port connections and have a two-way positive action. Four-way valves are widely used to provide on-off action in double-acting valves with a dual-acting cylinder/actuator. When the solenoid is turned off, it gives a full supply of air to one side of the actuator and exhausts the other to the atmosphere.
   
   

Conclusion:

Solenoid valves are available in many styles, each with its own set of functioning mechanisms and construction. The type to use is determined by many factors. The design and operating concept are primarily dictated by the desired action. Direct-acting and 2-way solenoid valves are ideal for systems that just require shut-off. More than a basic action is required in complex systems that mix or direct fluids. Additional ports are required in certain circuits. Overall, each solenoid valve is best suited to a specific use.