Solenoid valves – find manufacturers and suppliers

Solenoid valves are electrically controlled valves that are used to open, close or control the flow of liquids or gases.

They are based on an electromagnet that actuates a valve mechanism. These valves are widely used in a variety of applications, from industrial processes to automotive engineering and household appliances.

Here is a brief overview of how solenoid valves work as well as the types of solenoid valves, their uses and their advantages and disadvantages:

How solenoid valves work:

Solenoid valves essentially consist of two main components:

1. Solenoid (coil): A coil of wire that generates a magnetic field when an electric current is applied.
2. Valve mechanism: The part of the valve that lets the liquid or gas through or blocks it.

The way it works can be described as follows:

When an electric current is passed through the coil, it generates a magnetic field that moves the valve piston or armature.
Depending on the design of the valve, this either releases or stops the flow of a medium (liquid or gas).
As soon as the electric current is switched off, the piston returns to its original position due to a spring or the pressure of the medium.

Types of solenoid valves:

1. Direct operated solenoid valves:
   These valves are opened or closed by the direct movement of the armature through the magnetic force. The valve opens as soon as the solenoid attracts the armature and closes when the current is switched off.
   Suitable for small flow rates and low pressures, e.g. in water treatment plants or household appliances.
2. Pilot-operated (servo-controlled) solenoid valves:
   With these valves, the main flow is controlled via a small control hole that is opened or closed by the solenoid. The pressure difference on both sides of the valve then provides the actual control of the flow.
   Used for larger flow rates or higher pressures, e.g. in heating systems, air conditioning and ventilation systems or industrial machinery.
3. Pressure-controlled solenoid valves:
   The opening or closing process is controlled by the pressure of the medium. The solenoid only opens or closes a small pilot valve, while the pressure of the medium actuates the actual main valve.
   Ideal for applications where high pressures are processed, e.g. in compressed air systems or hydraulic systems.
4. 2-way, 3-way and 5-way solenoid valves:
   2-way valves: Have an inlet and an outlet and control the flow in one direction.
   3-way valves: Have an additional inlet or outlet and can divert the flow between two different paths. These valves are often used in compressed air control systems.
   5-way valves: Used to control more complex applications, such as the control of double-acting cylinders in pneumatic systems.
5. Proportional solenoid valves:
   These valves control the flow steplessly by varying the valve stroke in proportion to the electrical current. This allows the quantity of gas or liquid to be precisely controlled.
   Proportional solenoid valves are suitable for applications where precise, stepless control of pressure, flow or position is required.

Applications of solenoid valves:

1. Industry:
In industrial production processes, solenoid valves are used to control liquids or gases. They enable the automation of machines, e.g. in conveyor systems, cooling circuits or compressed air systems.
They are also used in chemical processes to precisely regulate the flow of chemicals, water or other media.

2. Medical devices:
Solenoid valves are used in devices such as ventilators, dialysis machines or laboratory dosing systems where precise liquid or gas flows are required.

3. Household appliances:
In appliances such as washing machines, dishwashers and coffee machines, solenoid valves regulate the water inlet and outlet.

4. Automotive industry:
Solenoid valves are used to control the flow of fuel in engines.
They control the flow of gases in systems such as exhaust gas recirculation (EGR) or AdBlue injection.

5. Irrigation systems:
Solenoid valves control the flow of water in automated irrigation systems used in agriculture or garden irrigation systems.

6. Heating, ventilation and air conditioning (HVAC) systems:
In HVAC systems, solenoid valves control the flow of refrigerants or water to maintain the desired temperature and pressure.

Advantages of solenoid valves:

• Solenoid valves can open and close very quickly, which is an advantage in many applications.
• As they are electrically operated, they can be easily integrated into automated systems and controlled remotely.
• Solenoid valves have few moving parts and are therefore durable and require little maintenance.
• They are available in a variety of materials, sizes and configurations and can be used for a wide range of liquids and gases.

Disadvantages of solenoid valves:

• Pilot operated solenoid valves require a minimum pressure to function. They are less suitable for very low pressures.
• During operation, solenoid valves require a constant power supply, which can lead to increased energy consumption in certain applications.
• Solenoid valves can become clogged or blocked by dirt or deposits in the medium, which requires regular cleaning.

Solenoid valves play an essential role in the control of liquid and gas flows in a variety of applications. They are versatile, from simple household appliances to complex industrial systems. Their ability to provide precise and automated control makes them indispensable in many areas.

Here is an overview of the most important points to consider when buying solenoid valves:

When purchasing solenoid valves, there are a number of important factors to consider to ensure that the valve you choose is suitable for the specific application.

• The type of valve is determined by the type of application:
• 2-way valves are most commonly used to either open or close a flow.
• 3-way or 5-way valves are required to divert flow between two different paths, such as in pneumatic or hydraulic systems.
• Make sure that the solenoid valve is suitable for the medium (liquid or gas). Depending on the type of medium (water, air, chemicals, oils, etc.), different valve materials and seals are required.
• Contaminated or abrasive media can damage valves. For such applications, valves with special filter mechanisms or more robust materials should be considered.
• The body material should be corrosion resistant and suitable for the medium. Common materials are:
• Brass: Often suitable for water and air.
• Stainless steel: Suitable for aggressive liquids, corrosive environments or food and pharmaceutical applications.
• Plastic: Lightweight but less resistant to high pressures and temperatures, but good for certain chemicals.
• The sealing materials influence the resistance to chemicals and the temperature tolerance:
• NBR (nitrile rubber): Suitable for oils, water and air.
• EPDM: Resistant to hot water and steam applications as well as some chemicals.
• FKM (Viton): Suitable for aggressive chemicals and high temperatures.
• The nominal size (DN) of the solenoid valve must match the pipeline to ensure a smooth flow. The size is often specified in inches or millimeters.
• The Kv value (flow coefficient) indicates how much fluid can flow through the valve at a certain pressure. Make sure that the Kv value of the valve meets your requirements.
• Direct operated solenoid valves open and close directly by the magnetic force, regardless of the operating pressure. These valves are well suited for applications with low pressure or small flow rates.
• Pilot operated solenoid valves use the pressure of the medium to control the main flow. They are ideal for higher pressures and larger volumes, but require a minimum pressure for operation.
• The solenoid valve must be designed for the operating pressure of the system. Pilot operated valves are more suitable for higher pressures, while direct operated valves can also operate at low or zero pressure.
• Check the temperature resistance of the valve (including the seals). It must be designed for the operating temperatures of the medium, both for liquids and gases.
• Solenoid valves are available in various electrical configurations, e.g. 12V, 24V, 110V, 230V in alternating current (AC) or direct current (DC). Make sure that the power supply of the system is compatible with the valve.
• Some solenoid valves have a high energy consumption, especially if they have to be kept constantly open or closed. In such cases, energy-saving valves can be an advantage.
• Make sure that the solenoid valve connections are compatible with your piping. common connection types are female thread, male thread, flanged connections or quick-release fittings.
• Some solenoid valves must be installed in a certain position (e.g. vertically) in order to function correctly. Check whether the valve is suitable for the desired installation position.
• Fail-safe options: Some solenoid valves are designed to return to a specific position (open or closed) in the event of a power failure. This is particularly important in safety-critical applications.
• Normally Closed (NC): The valve remains closed without power.
• Normally Open (NO): The valve remains open without power.
• Look for valves with a long service life, especially if they are used in continuous operation systems.
• Some valves are easier to maintain than others. Note the possibility of easy cleaning or maintenance, especially if the medium contains impurities.
• More expensive valves often offer higher resistance, better materials or longer service life. It is important to find a good balance between the cost and the specific requirements.
• Look for certifications that prove the reliability and safety of the valve (e.g. CE, ISO).

There are many technical and application-specific factors to consider when purchasing solenoid valves. It is important that the valves meet the requirements in terms of pressure, temperature, material and flow and can be integrated into the existing system. The choice of the right solenoid valves depends heavily on the intended application, be it in industry, medical technology, household appliances or automated processes.

Solenoid valves can be purchased from various suppliers. You will find comprehensive information on manufacturers and suppliers of Solenoid valves around the world on Exportpages.