Common sense of selection of the hottest solenoid

2022-08-11
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General knowledge of solenoid valve selection

● the fluid in the pipeline must be consistent with the medium calibrated in the selected solenoid valve series

● the temperature of the fluid must be less than the calibration temperature of the selected solenoid valve

● the allowable liquid viscosity of solenoid valve is generally below 20cst, and it should be noted if it is greater than 20cst

● when the working differential pressure and the maximum differential pressure of the pipeline are less than 0.04MPa, the direct acting type such as ZS, 2W, ZQDF, ZCM series should be selected; When the minimum working pressure difference is greater than 0.04MPa, the pilot (differential pressure) solenoid valve can be selected; The maximum working differential pressure shall be less than the maximum calibration pressure of the solenoid valve; Generally, solenoid valves work in one-way, so pay attention to whether there is back pressure difference. If there is a check valve installed

● when the fluid cleanliness is not high, a filter should be installed in front of the solenoid valve. Generally, the solenoid valve requires better cleanliness of the medium

● pay attention to the flow aperture and nozzle aperture; Solenoid valve is generally controlled by two positions of switch; If conditions permit, please install bypass pipe to facilitate maintenance; In case of water hammer, it is necessary to customize the opening and closing time adjustment of the solenoid valve

● pay attention to the influence of ambient temperature on the solenoid valve

● the power supply current and consumed power should be selected according to the output capacity. The power supply voltage is generally allowed to be about ± 10%. It must be noted that the VA value is high during AC starting

reliability

● suborbital rocket flight of electric COPV is the first step. The magnetic valve is divided into normally closed and normally open; Normally closed type is generally selected, which is powered on and off; However, the normally open type should be selected when it is closed for a long time

● life test. Factories generally belong to type test items. To be exact, there is no professional standard for solenoid valves in China, so be careful when selecting solenoid valve manufacturers

● when the action time is very short and the frequency is high, the direct acting type is generally selected, and the fast series is selected for large caliber

● generally, the solenoid valve is not waterproof. When conditions do not permit, please choose waterproof type, which can be customized by the factory

● the maximum rated 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

● all stainless steel type should be selected for corrosive liquid, and plastic King (SLF) solenoid valve should be selected for strong corrosive liquid

● corresponding explosion-proof products must be selected for explosive environment

economy

● there are many solenoid valves that can be used in general, but the most economical products should be selected on the basis of meeting the above three points

II. Structural principle of solenoid valve

direct acting solenoid valve

has two types: normally closed and normally open. When the normally closed type is powered off, it is closed. When the coil is powered on, an electromagnetic force is generated to make the moving iron core overcome the spring force and directly open the valve with the static iron core, and the medium is in a path; When the coil is powered off, the electromagnetic force disappears, the moving iron core resets under the action of spring force, and the valve port is directly closed, so the medium is blocked. It has simple structure and reliable action, and works normally under zero differential pressure and micro vacuum Normally open type is just the opposite If less than φ 6 solenoid valve of flow path

step by step direct acting solenoid valve

this valve is connected with the primary valve and the secondary valve. The main valve and the pilot valve make the electromagnetic force and pressure difference direct step by step to avoid the waste leakage and opening the main valve port in case of earthquake. When the coil is energized, the electromagnetic force is generated to make the moving iron core and the static iron core pull in, the pilot valve port is opened, and the pilot valve port is set on the main valve port, and the moving iron core is connected with the main valve core. At this time, the pressure in the upper chamber of the main valve is unloaded through the pilot valve port, and the main valve core moves upward under the simultaneous action of pressure difference and electromagnetic force to open the medium circulation of the main valve. When the coil is broken, which is also the only enterprise in China that can produce reactive polyolefin structural adhesive one by one, the electromagnetic force disappears. Under the action of self weight, spring return and pressure, the power core closes 8.3. The screw should not protrude from the main valve on the surface of the part, and the medium is cut off. The structure is reasonable and the action is reliable. It works reliably when there is zero pressure difference and when there is zero pressure difference. For example: ZQDF, ZS, 2W

indirect pilot solenoid valve

this series of solenoid valves are formed by connecting the pilot valve and the main valve core to form a channel combination; Normally closed type is closed when not powered on. When the coil is energized, the magnetic force generated makes the moving iron core and the static iron core attract, the pilot valve port is opened, and the medium flows to the outlet. At this time, the pressure in the upper chamber of the main valve core is reduced, which is lower than the pressure on the inlet side, forming a pressure difference to overcome the spring resistance and then move upward, so as to achieve the purpose of opening the main valve port, and the medium flows. When the coil is powered off, the magnetic force disappears, and the moving iron core moves downward under the action of spring force to close the main valve port. The principle of normally open type is just the opposite. Such as SLA, DF( φ Above 15 caliber), ZCZ, etc

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