As a core control component, solenoid valves play a vital role in transmission machinery and equipment, hydraulics, machinery, power, automobiles, agricultural machinery and other fields. According to different classification standards, solenoid valves can be divided into many types. The classification of solenoid valves will be introduced in detail below.
1. Classification by valve structure and material
According to different valve structures and materials, solenoid valves can be divided into six categories: direct-acting diaphragm structure, step-direct-acting diaphragm structure, pilot diaphragm structure, direct-acting piston structure, step-direct-acting piston structure and pilot piston structure. Branch subcategory. Each of these structures has its own characteristics and is suitable for different fluid control situations.
Direct-acting diaphragm structure: It has a simple structure and fast response speed, and is suitable for small flow and high frequency control.

Step-by-step direct-acting diaphragm structure: combines the advantages of direct action and pilot, and can work stably within a large pressure difference range.

Pilot diaphragm structure: The opening and closing of the main valve is controlled through the pilot hole, which has small opening force and good sealing performance.

Direct-acting piston structure: It has a large flow area and high pressure resistance, and is suitable for the control of large flow and high pressure.

Stepped direct-acting piston structure: It combines the advantages of direct-acting piston and pilot control, and can work stably within a large pressure difference and flow range.

Pilot piston structure: The pilot valve controls the opening and closing of the main valve, which has small opening force and high reliability.

2. Classification by function
In addition to being classified by valve structure and material, solenoid valves can also be classified by function. Common functional categories include water solenoid valves, steam solenoid valves, refrigeration solenoid valves, cryogenic solenoid valves, gas solenoid valves, fire solenoid valves, ammonia solenoid valves, gas solenoid valves, liquid solenoid valves, micro solenoid valves, and pulse solenoid valves. , hydraulic solenoid valves, normally open solenoid valves, oil solenoid valves, DC solenoid valves, high pressure solenoid valves and explosion-proof solenoid valves, etc.
These functional classifications are mainly divided according to the application occasions and fluid media of solenoid valves. For example, water solenoid valves are mainly used to control fluids such as tap water and sewage; steam solenoid valves are mainly used to control the flow and pressure of steam; refrigeration solenoid valves are mainly used to control fluids in refrigeration systems. When selecting a solenoid valve, you need to select the appropriate type according to the specific application and fluid medium to ensure the normal operation and long-term reliable operation of the equipment.
3. According to the valve body air path structure
According to the valve body air path structure, it can be divided into 2-position 2-way, 2-position 3-way, 2-position 4-way, 2-position 5-way, 3-position 4-way, etc.
The number of working states of the solenoid valve is called “position”. For example, the commonly seen two-position solenoid valve means that the valve core has two controllable positions, corresponding to the two on-off states of the air path, open and closed. The solenoid valve and the pipe The number of interfaces is called “pass”. Common ones include 2-way, 3-way, 4-way, 5-way, etc. The structural difference between the two-way solenoid valve and the three-way solenoid valve is that the three-way solenoid valve has an exhaust port while the former does not. The four-way solenoid valve has the same function as the five-way solenoid valve. The former has one exhaust port and the latter has two. The two-way solenoid valve has no exhaust port and can only cut off the flow of fluid medium, so it can be directly used in process systems. The multi-way solenoid valve can be used to change the flow direction of the medium. It is widely used in various types of actuators.
4. According to the number of solenoid valve coils
According to the number of solenoid valve coils, they are divided into single solenoid control and double solenoid control.
A single coil is called a single solenoid control, a double coil is called a double solenoid control, 2-position 2-way, 2-position 3-way are all single-switch (single coil), 2-position 4-way or 2-position 5-way can be used It is a single electric control (single coil)
•Can also be dual electronically controlled (double coil)
When selecting a solenoid valve, in addition to considering classification, you also need to pay attention to some important parameters and characteristics. For example, fluid pressure range, temperature range, electrical parameters such as voltage and current, as well as sealing performance, corrosion resistance, etc. all need to be considered. In addition, it needs to be customized and installed according to actual needs and equipment characteristics to meet fluid pressure differential conditions and other requirements.
The above is a detailed introduction to the classification of solenoid valves. I hope it can provide you with a useful reference when selecting and using solenoid valves.

Basic knowledge of solenoid valve
1. Working principle of solenoid valve
Solenoid valve is an automation component that uses electromagnetic principles to control fluid flow. Its working principle is based on the attraction and release of the electromagnet, and controls the on-off or direction of the fluid by changing the position of the valve core. When the coil is energized, an electromagnetic force is generated to move the valve core, thereby changing the state of the fluid channel. The electromagnetic control principle has the characteristics of rapid response and precise control.
Different types of solenoid valves work on different principles. For example, direct-acting solenoid valves directly drive the movement of the valve core through electromagnetic force; step-by-step direct-acting solenoid valves use a combination of a pilot valve and a main valve to control high-pressure and large-diameter fluids; pilot-operated solenoid valves use The pressure difference between the pilot hole and the main valve controls the fluid. These different types of solenoid valves have a wide range of applications in industrial automation.
2. Structure of solenoid valve
The basic structure of the solenoid valve includes valve body, valve core, coil, spring and other components. The valve body is the main part of the fluid channel and bears the pressure and temperature of the fluid; the valve core is a key component that controls the on-off or direction of the fluid, and its movement state determines the opening and closing of the fluid channel; the coil is the part that generates electromagnetic force, which passes through The change in current controls the movement of the valve core; the spring plays a role in resetting and maintaining the stability of the valve core.
In the structure of the solenoid valve, there are also some key components such as seals, filters, etc. The seal is used to ensure the sealing between the valve body and the valve core to prevent fluid leakage; the filter is used to filter impurities in the fluid and protect the internal components of the solenoid valve from damage.
3. The interface and diameter of the solenoid valve
The interface size and type of the solenoid valve are designed according to the needs of the fluid pipeline. Common interface sizes include G1/8, G1/4, G3/8, etc., and interface types include internal threads, flanges, etc. These interface sizes and types ensure a smooth connection between the solenoid valve and the fluid pipeline.
The diameter refers to the diameter of the fluid channel inside the solenoid valve, which determines the flow rate and pressure loss of the fluid. The size of the diameter is selected based on the fluid parameters and pipeline parameters to ensure the smooth flow of fluid inside the solenoid valve. The selection of the path also needs to consider the size of impurity particles in the fluid to avoid particles blocking the channel.
4. Selection parameters of solenoid valve
When selecting, the first thing to consider is the pipeline parameters, including pipeline size, connection method, etc., to ensure that the solenoid valve can be smoothly connected to the existing pipeline system. Secondly, fluid parameters such as medium type, temperature, viscosity, etc. are also key considerations, which directly affect the material selection and sealing performance of the solenoid valve.
Pressure parameters and electrical parameters cannot be ignored either. Pressure parameters include the working pressure range and pressure fluctuations, which determine the pressure-bearing capacity and stability of the solenoid valve; and electrical parameters, such as power supply voltage, frequency, etc., need to match the on-site power supply conditions to ensure the normal operation of the solenoid valve.
The choice of action mode depends on the specific application scenario, such as normally open type, normally closed type or switching type, etc. Special requirements such as explosion-proof, anti-corrosion, etc. also need to be fully considered during model selection to meet the safety and use needs in specific environments.
Solenoid Valve Selection Guide
In the field of industrial automation, solenoid valve is a key component of fluid control, and its selection is particularly important. An appropriate selection can ensure the stable operation of the system, while an improper selection may lead to equipment failure or even safety accidents. Therefore, when selecting solenoid valves, certain principles and steps must be followed, and relevant selection matters must be paid attention to.
1. Selection principles
Safety is the primary principle for solenoid valve selection. It must be ensured that the selected solenoid valve will not cause harm to personnel and equipment during operation. Applicability means that the solenoid valve must meet the control requirements of the system and be able to reliably control the on-off and flow direction of the fluid. Reliability requires solenoid valves to have a long service life and a low failure rate to reduce maintenance costs. Economy is to choose products with reasonable price and high cost performance as much as possible on the premise of meeting the above requirements.
2. Selection steps
First of all, it is necessary to clarify the working conditions and requirements of the system, including the properties of the fluid, temperature, pressure and other parameters, as well as the system’s control method, action frequency, etc. Then, according to these conditions and requirements, select the appropriate solenoid valve type, such as two-position three-way, two-position five-way, etc. Next, determine the specifications and dimensions of the solenoid valve, including interface size, diameter, etc. Finally, select additional functions and options according to actual needs, such as manual operation, explosion-proof, etc.
3. Precautions for selection
During the selection process, special attention needs to be paid to the following aspects: First, corrosive media and material selection. For corrosive media, solenoid valves made of corrosion-resistant materials should be selected, such as plastic valves or all-stainless steel products. Next is the explosive environment and explosion-proof level. In explosive environments, solenoid valves that meet the requirements of the corresponding explosion-proof level must be selected. In addition, factors such as the adaptability of environmental conditions and solenoid valves, the matching of power supply conditions and solenoid valves, action reliability and protection of important occasions, as well as brand quality and after-sales service considerations, must also be considered. Only by comprehensively considering these factors can we choose a solenoid valve product that is both safe and economical.