Selection principle of electromagnetic directional valve

The selection of electromagnetic directional valve should first follow the four principles of safety, reliability, applicability and economy, and then it should be selected according to six aspects of site conditions (i.e. pipeline parameters, fluid parameters, pressure parameters, electrical parameters, operation mode and special requirements).

Selection basis:

1. According to the pipeline parameters, select the size (DN) and interface mode of the solenoid valve

1) Determine the diameter (DN) according to the internal diameter or flow requirements of the field pipeline;

2) The interface mode, generally > DN50, needs to select flange interface, and ≤ DN50 can be freely selected according to user needs.

2. Select the material and temperature group of the solenoid valve according to the fluid parameters

1) Corrosive fluid: corrosion resistant solenoid valve and all stainless steel should be selected; edible super clean fluid: food grade stainless steel solenoid valve should be selected;

2) High temperature fluid: solenoid valve made of high temperature resistant electrical materials and sealing materials shall be selected, and piston type structure shall be selected;

3) Fluid state: it must be distinguished from gas state, liquid state or mixed state, especially when the diameter is larger than DN25;

4) Viscosity of fluid: generally under 50cst, you can choose freely. If it exceeds this value, you need to choose high viscosity solenoid valve.

3. Selecting the principle and structure of the solenoid valve according to the pressure parameters

1) Nominal pressure: the meaning of this parameter is the same as that of other general valves, which is determined according to the nominal pressure of the pipeline;

2) Working pressure: if the working pressure is low, the principle of direct acting or step-by-step direct acting must be selected; when the minimum working pressure difference is above 0.04MPa, the direct acting, step-by-step direct acting and pilot acting can be selected.

4. Electrical selection: AC220V and DC24 shall be preferred as far as possible.

5. Select according to the duration of operation: 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 shall be selected;

2) If the opening time is short or the opening and closing time is not long, select the normally closed type;

3) However, some working conditions for safety protection, such as furnace and kiln flame monitoring, can not be selected as normally open ones, but should be selected as long-term energized ones.

6. Select auxiliary functions according to environmental requirements: explosion-proof, check, manual, waterproof fog, water spray, diving.