First, the fluid in the applicability pipeline must be consistent with the media in the selected solenoid valve series model.
The temperature of the fluid must be less than the calibrated temperature of the selected solenoid valve. Solenoid valves allow the viscosity of liquids to be generally below 20CST, and should be indicated when more than 20CST. Working pressure difference, the maximum pressure difference in the pipeline is less than 0.04MPa should be used such as ZS, 2W, ZQDF, ZCM series of direct-acting and step-by-step direct-acting; minimum operating pressure difference is greater than 0.04MPa, the choice of pilot type ( Differential pressure type) solenoid valve; the maximum working pressure differential should be less than the maximum calibration pressure of the solenoid valve; general electromagnetic valve is one-way operation, so pay attention to whether there is back pressure difference, if installed check valve.
When the fluid cleanliness is not high, a filter should be installed in front of the solenoid valve. The liquid gas solenoid valve requires better cleanliness of the medium. Pay attention to the flow aperture and the nozzle diameter; solenoid valve is generally only two-way control switch; conditions allow to install the bypass pipe, easy to repair; have water hammer phenomenon to customize the solenoid valve opening and closing time adjustment. 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 at the time of AC start is high.
Second, the reliability of electromagnetic valve is divided into normally closed and normally open two kinds; generally used normally closed type, open power, power off; but in the very long open time is very short when closed to use normally open type.
Life test, the factory is generally a type test project, to be exact, there is no professional standard for solenoid valve in China, so choose the electromagnetic valve manufacturer carefully.
When the operation time is very short, the direct-acting type is generally selected and the large-caliber selection is used for the fast series.
Third, security General solenoid valve is not waterproof, please use waterproof type when the conditions are not allowed, the factory can be customized. The highest rated pressure of the solenoid valve must exceed the maximum pressure in the pipeline, otherwise the service life will be shortened or other unexpected situations will occur. Corrosive liquids should be made of all-stainless steel type, and strong corrosive fluids should use plastic king (SLF) solenoid valves. Explosion-proof products must be selected for explosive environments.
Fourth, economical There are many solenoid valves that can be used universally, but the most economical products should be chosen on the basis of satisfying the above three points.
The structural principle of the electromagnetic valve A direct-acting electromagnetic valve has two types, normally closed and normally open. Normally closed type when the power is off, when the coil is energized, electromagnetic force is generated, so that the moving core overcomes the spring force and the static iron core directly opens the valve and the medium is the passage; when the coil is powered off, the electromagnetic force disappears, and the moving iron disappears. The core is reset under the action of the spring force, and the valve port is closed directly, and the medium is blocked. Simple structure, reliable operation, normal work under zero differential pressure and micro vacuum. Normally open type is just the opposite. If less than φ6 flux diameter solenoid valve.
Second, step-by-step direct-acting solenoid valve The valve is used once to open the valve and the second valve is connected in one, the main valve and the pilot valve step by step to make the electromagnetic force and pressure difference directly open the main valve port. When the coil is energized, an electromagnetic force is generated to cause the moving iron core and the static iron core to pull in. The pilot valve port is opened and the pilot valve port is located on the main valve port, and the moving iron core is connected with the main valve core. At this time, the main valve is The pressure of the chamber is unloaded through the pilot valve port, and the main valve core is moved upwards under the influence of the pressure difference and the electromagnetic force to open the main valve medium. When the coil is de-energized, the electromagnetic force disappears. At this moment, the moving iron core closes the pilot valve hole under the action of its own weight and spring force. At this moment, the medium enters the upper cavity of the main valve core in the balance hole, so that the pressure of the upper chamber rises. The main valve is closed under the action of spring return and pressure, and the medium is shut off. Reasonable structure, reliable operation, and reliable operation at zero differential pressure. Such as: ZQDF, ZS, 2W and so on.
Third, the indirect pilot solenoid valve This series of solenoid valve is formed by the combination of the pilot valve and the main valve core to form a channel; normally closed type is closed when not powered. When the coil is energized, the generated magnetic force causes the moving iron core and the static iron core to pull in, the pilot valve port opens, and the medium flows toward the outlet. At this time, the pressure of the upper valve of the main valve plug decreases, which is lower than the pressure of the inlet side, forming a pressure difference against the spring. The resistance moves upwards and reaches the purpose of opening the main valve port, and the medium circulates. When the coil is de-energized, the magnetic force disappears and the moving iron core resets and closes the pilot port under the action of the spring force. At this moment, the medium flows from the balancing hole, the pressure of the upper cavity of the main valve core increases, and the downward movement of the main valve core is caused by the force of the spring. Close the main valve port. The normally open principle is just the opposite. Such as: SLA, DF (φ15 above diameter), ZCZ and so on.
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