When the reaction coil is energized, the reaction gas path is connected (the reaction air hole is filled with gas). Even after the reactive coil is de-energized, the reactive gas path is still connected and will remain energized until the positive coil is energized. This is equivalent to "self-locking".
2. The two-position three-way solenoid valve is divided into normally closed type and normally open type. Normally closed type means that the air path is disconnected when the coil is not energized, and normally open type means that the air path is disconnected when the coil is not energized.
Working principle of normally closed two-position three-way solenoid valve: when the coil is energized, the gas path is connected, and once the coil is de-energized, the gas path will be disconnected, which is equivalent to "inching".
3. Working principle of normally open two-position three-way single electric control solenoid valve: When the coil is energized, the gas path is disconnected. Once the coil is cut off, the gas path will be connected, which is also "inching". A single electronic controller has only one electromagnetic head. After the power supply is turned on, the solenoid valve reverses direction. After power failure, the solenoid valve is reset due to the action of the spring.
4. The dual electronic control two-position solenoid valve has two electromagnetic heads, and only one of them can be energized. When the power is turned on, the solenoid valve will change direction. After power failure, the solenoid valve will keep its position, and it will return to its original position only after another electromagnetic head is energized.
Extended data
Selection basis
The selection of solenoid valves should first follow the four principles of safety, reliability, applicability and economy, and then be selected according to six field working conditions (namely, pipeline parameters, fluid parameters, pressure parameters, electrical parameters, action modes and special requirements).
Selection basis:
1. Select the size (DN) and interface mode of the solenoid valve according to the pipeline parameters.
1) Determine the pipe diameter (DN) according to the internal diameter or flow requirements of the on-site pipeline;
2) Interface mode: generally, flange interface should be selected for > DN50, and ≤DN50 can be freely selected according to user's needs.
2. Select the material and temperature group of the solenoid valve according to the fluid parameters.
1) corrosive fluid: corrosion-resistant solenoid valves and all stainless steel should be selected; Edible ultra-clean fluid: food-grade stainless steel solenoid valve should be selected;
2) High-temperature fluid: The electromagnetic valve shall be made of high-temperature resistant electrical materials and sealing materials, and the piston structure type shall be selected;
3) Fluid state: large to gaseous, liquid or mixed state, especially when the diameter is greater than DN25, it must be distinguished;
4) Fluid viscosity: generally less than 50cSt can be selected; If it exceeds this value, a high-viscosity solenoid valve should be selected.
3. Selection of solenoid valve according to pressure parameters: principle and structural changes.
1) Nominal pressure: this parameter has the same meaning as other general valves and is determined according to the nominal pressure of the pipeline;
2) Working pressure: If the working pressure is low, you must choose the principle of direct action or step-by-step direct action; When the minimum working pressure difference is above 0.04Mpa, direct-acting type, step-by-step direct-acting type and pilot type can be selected.
4. Electrical selection: AC220V and DC24 are preferred as far as possible for voltage specifications, which is more convenient.
5. Choose according to the length of continuous working time: normally closed, normally open or continuously energized.
1) When the solenoid valve needs to be opened for a long time, and the duration is longer than the closing time, the normally open type should be selected;
2) If the opening time is short or the opening and closing time is short, the normally closed type is selected;
3) However, some working conditions used for safety protection, such as furnace flame monitoring, can't be turned on normally, and should be electrified for a long time.
6. Choose auxiliary functions according to environmental requirements: explosion-proof, inspection, manual, anti-fog, water shower and diving.
References:
Baidu encyclopedia-two-position five-way solenoid valve
Baidu encyclopedia-two-position three-way solenoid valve
Baidu encyclopedia-double control solenoid valve
Baidu encyclopedia-electromagnetism valve