1、 Characteristics of solenoid valve

1. Choose different types of solenoid valves for gas, liquid or mixed states, such as ZQDF for air, ZQDF-Y for liquid, ZQDF-2 (or -3) for steam, otherwise it may cause misoperation. The ZDF series multifunctional solenoid valve can be connected to air Liquid. It is best to inform the media status when booking, so that the installation user does not need to adjust it again.

2. Products with different specifications and medium temperatures may cause the coil to burn out and the seals to age, seriously affecting their lifespan.

3. The viscosity of the medium is usually below 50cSt. If the diameter exceeds 15mm, use the ZDF series multifunctional solenoid valve for special ordering. High viscosity solenoid valve with a diameter less than 15mm.

4. When the cleanliness of the medium is not high, a backwash filter valve should be installed in front of the solenoid valve. When the pressure is low, a direct acting diaphragm solenoid valve such as CD-P can be used.

5. If the medium flows in a directional manner and does not allow reverse flow, ZDF-N and ZQDF-N need to flow in both directions. Please make special requirements. The temperature of the medium should be selected within the allowable range of the solenoid valve.

2、 Pipeline parameters

1. Select valve ports and models based on the requirements of medium flow direction and pipeline connection method. For example, for switching from one pipeline to two pipelines, CA5 and Z3F are selected for small diameters, and ZDF-Z1/2 is selected for medium or large diameters. For controlling the convergence of two pipelines, please choose ZDF-Z2/1, etc.

2. Select the nominal diameter based on the flow rate and valve Kv value, or choose the same pipe inner diameter. Please note that some manufacturers do not indicate the Kv value, and the valve hole size is often smaller than the interface pipe diameter. Do not be tempted by low prices and make mistakes.

3. Work pressure difference. Indirect pilot type can be used when the minimum working pressure difference is above 0.04Mpa; For those with a minimum working pressure difference close to or less than zero, direct acting or step-by-step direct acting must be selected.

3、 Environmental conditions

1. The maximum and minimum temperatures of the environment should be selected within the allowable range. If there is any deviation, special orders should be made.

2. In environments with high relative humidity and water droplets and rain, waterproof solenoid valves should be selected.

3. Special types such as marine solenoid valves should be selected for situations where there are frequent vibrations, bumps, and impacts in the environment.

4. When used in corrosive or explosive environments, priority should be given to selecting corrosion-resistant materials based on safety requirements.

5. If the environmental space is limited, please choose a multifunctional solenoid valve as it eliminates the need for a bypass and three manual valves, and is easy to maintain online.

1. Switch form:

The solenoid valve is driven by a coil and can only be turned on or off, with a short action time when turned on or off.

The driving of electric valves is usually done by motors, and the opening or closing action requires a certain amount of time for analog measurement, which can be adjusted.

2. Job nature:

Electromagnetic valves generally have a small flow coefficient and a small working pressure difference. For example, the flow coefficient of a typical 25 caliber solenoid valve is much smaller than that of a 15 caliber electric ball valve. The drive of solenoid valves is through electromagnetic coils, which are relatively easy to be damaged by voltage surges. Equivalent to the function of a switch, it has two functions: on and off.

Electric valves are generally driven by motors, which are more resistant to voltage surges. Electromagnetic valves are quick opening and quick closing, generally used in places with low flow and low pressure, requiring high switching frequency. Electric valves are the opposite. The opening of the electric valve can be controlled, with states including open, closed, and half open/half closed, which can control the flow rate of the medium in the pipeline. However, the solenoid valve cannot meet this requirement.

Electromagnetic valves can generally reset when powered off, while electric valves require a reset device for this function.

3. Applicable process:

Electromagnetic valves are suitable for some special process requirements, such as leakage, special fluid media, etc., and are relatively expensive.

Electric valves are generally used for regulation, and there are also switch quantities, such as at the end of fan coil units.

There are many types of solenoid valves, and different solenoid valves play a role in different positions of the control system. The most commonly used ones are one-way valves, safety valves, directional control valves, speed regulating valves, etc.

Working principle

The solenoid valve has a sealed chamber with through holes at different positions, each connected to a different oil pipe. The middle of the chamber is a piston, and there are two electromagnets on both sides. The valve body will be attracted to which side when the magnet coil on the other side is energized. By controlling the movement of the valve body, different oil discharge holes can be opened or closed. The oil inlet hole is normally open, and hydraulic oil will enter different oil discharge pipes. Then, the pressure of the oil will push the piston of the oil cylinder, which in turn drives the piston rod, which drives the mechanical device. In this way, the mechanical motion is controlled by controlling the current on and off of the electromagnet.

Main classification

1. Electromagnetic valves can be classified into three main categories based on their principles:

Direct acting solenoid valve

Principle: When powered on, the electromagnetic coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; When the power is cut off, the electromagnetic force disappears, and the spring presses the closing member against the valve seat, causing the valve to close.

Characteristics: It can work normally under vacuum, negative pressure, and zero pressure, but the diameter generally does not exceed 25mm.

Step by step direct acting solenoid valve

Principle: It is a combination of direct action and pilot operated principle. When there is no pressure difference between the inlet and outlet, after being energized, the electromagnetic force directly lifts the pilot small valve and the main valve closing member upward in sequence, and the valve opens. When the inlet and outlet reach the starting pressure difference, after being energized, the electromagnetic force pilot small valve, the lower chamber pressure of the main valve rises, and the upper chamber pressure drops, thereby using the pressure difference to push the main valve upwards; When the power is cut off, the pilot valve uses spring force or medium pressure to push the closing member downwards, causing the valve to close.

Features: It can also operate under zero pressure difference, vacuum, and high pressure, but with high power, it must be installed horizontally.

Pilot operated solenoid valve

Principle: When powered on, the electromagnetic force opens the pilot hole, causing the pressure in the upper chamber to rapidly decrease, creating a pressure difference of high and low around the closing element. The fluid pressure pushes the closing element to move upward, and the valve opens; When the power is cut off, the spring force closes the pilot hole, and the inlet pressure quickly forms a lower and higher pressure difference around the closing valve through the bypass hole. The fluid pressure pushes the closing valve to move downward and close the valve.

Features: The upper limit of the fluid pressure range is relatively high, and it can be installed freely (customized), but it must meet the fluid pressure difference conditions.

2. Electromagnetic valves are divided into six sub categories based on differences in valve structure, materials, and principles: direct acting diaphragm structure, step-by-step direct acting diaphragm structure, pilot diaphragm structure, direct acting piston structure, step-by-step direct acting piston structure, and pilot piston structure.

3. Electromagnetic valves are classified according to their functions: water solenoid valves, steam solenoid valves, refrigeration solenoid valves, low-temperature solenoid valves, gas solenoid valves, fire solenoid valves, ammonia solenoid valves, gas solenoid valves, liquid solenoid valves, miniature solenoid valves, pulse solenoid valves, hydraulic solenoid valves, normally open solenoid valves, oil solenoid valves, DC solenoid valves, high-voltage solenoid valves, explosion-proof solenoid valves, etc.

The steam solenoid valves we come into contact with in our daily lives are often divided into two types:

1. Boiler steam - saturated steam

2. Steam from thermal power plants - superheated steam

1. Saturated steam: relatively stable temperature and pressure, temperature below 250 ℃, working pressure below 1.6Mpa

2. Overheated steam: with a large base of temperature and pressure changes, the highest temperature can reach over 400 ℃, and the working pressure is below 4.0Mpa

Classification of steam solenoid valves

For the first type of steam, we usually choose soft sealed steam solenoid valves.

Structural characteristics

This valve is a pilot operated secondary opening solenoid valve composed of two main components: the auxiliary valve and the main valve

advantage

Heat resistance: Special high-temperature resistant electrical and sealing materials are used for the electromagnetic and sealing parts, and various insulation measures are applied

Wear resistant: Reasonable material selection, valve cup and guide sleeve cleverly utilize the lubrication effect of fluid to reduce wear and improve service life

Condensation resistance: The condensation water in the steam pipeline is an important factor affecting the operation of the steam solenoid valve, while this valve is not affected by condensation water

Soft sealed solenoid valve

This series of solenoid valves can also be widely used in textile, printing, chemical, plastic, rubber, pharmaceutical, food, building materials, machinery, electrical, surface treatment steam solenoid valves, scientific research departments, as well as automatic control systems for bathrooms, canteens, air conditioning, etc.

Classification of steam solenoid valves

For the second type of steam, we usually choose hard sealed steam solenoid valves

Structural characteristics

Adopting metal hard sealing improves the product's operating temperature and service life

Reasonable material selection, cleverly utilizing the lubrication effect of fluid in the valve cup and guide sleeve to reduce wear

Hard sealed solenoid valve

This product has a wide range of universal media and can be used for fluids such as water, light oil, heavy oil, non corrosive gases, and steam.

In the drainage system of power station exhaust pipelines and the exhaust system of evaporators, the main function is to perform dual position automatic regulation and remote control of the medium in the pipelines.

working condition

Normally closed - powered on to open, powered off to close

Normally open - power off to open, power on to close

The steam solenoid valves we come into contact with in our daily lives are often divided into two types:

1. Boiler steam - saturated steam

2. Steam from thermal power plants - superheated steam

1. Saturated steam: relatively stable temperature and pressure, temperature below 250 ℃, working pressure below 1.6Mpa

2. Overheated steam: with a large base of temperature and pressure changes, the highest temperature can reach over 400 ℃, and the working pressure is below 4.0Mpa

Classification of steam solenoid valves

For the first type of steam, we usually choose soft sealed steam solenoid valves.

Structural characteristics

This valve is a pilot operated secondary opening solenoid valve composed of two main components: the auxiliary valve and the main valve

advantage

Heat resistance: Special high-temperature resistant electrical and sealing materials are used for the electromagnetic and sealing parts, and various insulation measures are applied

Wear resistant: Reasonable material selection, valve cup and guide sleeve cleverly utilize the lubrication effect of fluid to reduce wear and improve service life

Condensation resistance: The condensation water in the steam pipeline is an important factor affecting the operation of the steam solenoid valve, while this valve is not affected by condensation water

Soft sealed solenoid valve

This series of solenoid valves can also be widely used in textile, printing, chemical, plastic, rubber, pharmaceutical, food, building materials, machinery, electrical, surface treatment steam solenoid valves, scientific research departments, as well as automatic control systems for bathrooms, canteens, air conditioning, etc.

Classification of steam solenoid valves

For the second type of steam, we usually choose hard sealed steam solenoid valves

Structural characteristics

Adopting metal hard sealing improves the product's operating temperature and service life

Reasonable material selection, cleverly utilizing the lubrication effect of fluid in the valve cup and guide sleeve to reduce wear

Hard sealed solenoid valve

This product has a wide range of universal media and can be used for fluids such as water, light oil, heavy oil, non corrosive gases, and steam.

In the drainage system of power station exhaust pipelines and the exhaust system of evaporators, the main function is to perform dual position automatic regulation and remote control of the medium in the pipelines.

working condition

Normally closed - powered on to open, powered off to close

Normally open - power off to open, power on to close