Knowledge

Precautions for solenoid valve selection



One: applicability
The fluid in the line must match the medium calibrated in the selected solenoid valve series.
The temperature of the fluid must be less than the calibration temperature of the solenoid valve selected.
Solenoid valves allow liquid viscosity to be generally below 20 CST, and greater than 20 CST should be noted.
Working pressure difference, the maximum pressure difference of the pipeline should be less than 0.04MPa, such as ZS, 2W, ZQDF, ZCM series and other direct-acting and step-by-step direct-acting type; when the minimum working pressure difference is greater than 0.04MPa, the pilot type can be used. Differential) Solenoid valve; the maximum working pressure difference should be less than the maximum calibration pressure of the solenoid valve; the general solenoid valve is one-way work, so pay attention to whether there is a back pressure difference, if there is a check valve installed.
When the fluid cleanliness is not high, the filter should be installed in front of the solenoid valve. Generally, the solenoid valve requires good cleanliness of the medium.
Pay attention to the flow aperture and the diameter of the nozzle; the solenoid valve is generally only controlled by the two-position switch; if necessary, please install the bypass tube for easy maintenance; when there is water hammer, customize the opening and closing time of the solenoid valve.
Pay attention to the influence of ambient temperature on the solenoid valve
The power supply current and power consumption should be selected according to the output capacity. The power supply voltage is generally allowed to be ±10%. It must be noted that the VA value is higher when the AC starts.
Second, reliability
The solenoid valve is divided into two types: normally closed and normally open; generally, the normally closed type is used, the power is turned on, and the power is turned off; but when the opening time is long, the normally open type is selected when the closing time is short.
Life test, the factory is generally a type test project, to be exact, there is no professional standard for solenoid valves in China, so the choice of solenoid valve manufacturers is cautious.
When the action time is short and the frequency is high, the direct motion type is generally selected, and the large diameter is selected as the fast series.
Third, security
Generally, the solenoid valve is not waterproof. When the conditions are not allowed, please choose waterproof type, the factory can be customized.
The highest nominal pressure of the solenoid valve must exceed the maximum pressure in the pipeline, otherwise the service life will be shortened or other accidents will occur.
Corrosive liquids should be selected from all stainless steel type, and strong corrosive fluids should be selected from plastic king (SLF) solenoid valves.
Explosive environments must use the corresponding explosion-proof products.
Fourth, economic
There are many solenoid valves that can be used universally, but the most economical products should be selected on the basis of meeting the above three points.

Selection of solenoid valve
Solenoid valve selection should first follow the four principles of safety, reliability, applicability and economy, followed by six aspects of field conditions (ie pipeline parameters, fluid parameters, pressure parameters, electrical parameters, modes of operation, Special requirements are selected).
Selection basis:
First, select the solenoid valve according to the pipeline parameters: the diameter specification (ie DN), interface mode
1. Determine the diameter (DN) size according to the inner diameter of the pipeline or the flow requirement.
2, interface mode, general > DN50 to choose the flange interface, ≤ DN50 can be freely selected according to user needs.
Second, according to the fluid parameters to select the solenoid valve: material, temperature group
1, corrosive fluid: should choose corrosion-resistant solenoid valve and all stainless steel; edible ultra-clean fluid: food grade stainless steel solenoid valve should be used.
2, high temperature fluid: to choose the use of high temperature resistant electrical materials and sealing materials made of solenoid valves, and to choose the type of piston structure.
3, fluid state: large to have a gaseous state, liquid or mixed state, especially when the caliber is larger than DN25 when ordering must be distinguished.
4, fluid viscosity: usually below 50cSt can be arbitrarily selected, if this value is exceeded, the high viscosity solenoid valve should be used.
Third, select the solenoid valve according to the pressure parameters: principle and structure variety
1. Nominal pressure: This parameter has the same meaning as other general-purpose valves and is determined according to the nominal pressure of the pipeline.
2. Working pressure: If the working pressure is low, the direct-acting or step-by-step direct-acting principle must be used; when the minimum working pressure difference is above 0.04Mpa, direct-acting, step-by-step direct-acting, and pilot-operated can be used.
Fourth, electrical selection: voltage specifications should be preferred to use AC220V, DC24 is more convenient.
5. Choose according to the length of continuous working hours: normally closed, normally open, or continuously energized
1. When the solenoid valve needs to be opened for a long time, and the duration of the excess closing time should be the normally open type.
2. If the opening time is short or the opening and closing time is not much, then the normally closed type is selected.
3. However, some working conditions for safety protection, such as furnace and kiln flame monitoring, cannot be selected for normal opening.
6. Select auxiliary functions according to environmental requirements: explosion-proof, non-return, manual, waterproof fog, water shower, diving
1. Explosive environment: The corresponding explosion-proof solenoid valve must be selected (our company has: d II BT4, d II CT5, Ex m I/II T4).
2. When the fluid in the pipe has a backflow phenomenon, you can choose our company's OK71-N and OK72-N series with non-return function solenoid valve.
3. When it is necessary to carry out on-site manual operation of the solenoid valve, we can choose our company's OK71-S and OK72-S series with manual function solenoid valve.
4. For outdoor installation or dusty occasions, waterproof and dustproof varieties should be used (protection level is above IP54).
5. For the fountain, a submersible solenoid valve must be used (protection level is above IP68).