There are many parameters of the solenoid valve, the product type is also rich, medium, pressure, temperature, normally open, normally closed, voltage, power, explosion-proof and other parameters, the choice of solenoid valve products may be different; therefore, there are It is necessary to analyze the product selection of the solenoid valve; mainly from the product characteristics and parameters of the solenoid valve, this article will take the famous imported solenoid valve brand German Lite LIT as an example to analyze the selection of the solenoid valve;
When choosing a solenoid valve, we should mainly consider the applicability, reliability and safety of the solenoid valve.
First, the applicability of the solenoid valve
Media characteristics
1. Different types of solenoid valves are used in the gas, liquid or mixed state. For example, ZQDF is used for air, ZQDF-Y is used for liquid, ZQDF-2 (or ZQDF-3) is used for steam, otherwise it may cause malfunction. The ZDF series of multi-function solenoid valves are open to gas and liquid. When the most hao is ordered, the media status is declared, and the user is not required to adjust the mode.
2, the medium temperature is different specifications of the product, otherwise the coil will burn out, the seal is aging, seriously affecting the life expectancy. The temperature of the German LIT solenoid valve is -196 ° C -600 ° C, a wide range;
3, the viscosity of the medium, usually below 50cSt. If this value is exceeded, the diameter is greater than 15mm. Use the ZDF series multi-function solenoid valve for special order. A high viscosity solenoid valve with a diameter of less than 15mm.
4. When the cleanliness of the medium is not high, the backflush filter valve should be installed in front of the solenoid valve. For low pressure, the direct-acting diaphragm type solenoid valve can be used as CD-P for example.
5. If the medium is directional, and the backflow of ZDF-N and ZQDF-N is not allowed to be used in both directions, please make special requests.
6, the medium temperature should be selected within the allowable range of the solenoid valve
Pipeline parameter
1. Select the valve port and model according to the flow direction requirements and pipe connection method. For example, for a pipe to switch to two pipes, CA5 and Z3F for small diameter, ZDF-Z1/2 for medium or large diameter. For example, if you want to control the convergence of two pipes, please choose ZDF-Z2/1.
2. The nominal diameter is selected according to the flow rate and the valve Kv value, and the inner diameter of the pipe can also be selected. Please note that some manufacturers do not have a Kv value, and the valve hole size is often smaller than the interface diameter.
3. The minimum working pressure difference is above 0.04Mpa, which is optional indirect pilot type; the minimum working pressure difference is close to or less than zero, you must use direct-acting or step-by-step direct type; take German Lite LIT as an example, generally use pressure 0.2Mpa In the following, the imported direct-acting solenoid valve is used, and the pressure of 0.2Mpa or more is used, and the inlet pilot type solenoid valve is selected.
Environmental conditions
1. The most gao and minimum temperature of the environment should be selected within the allowable range. If there is a tolerance, special order should be made.
2. In the environment where the relative humidity is high and there are water droplets and rain, the waterproof solenoid valve should be selected.
3, the environment often has vibration, bumps and impacts, etc. should choose special varieties, such as marine solenoid valves.
4. In the corrosive or explosive environment, the use of corrosion resistance should be preferred according to the safety requirements.
5. If the environmental space is limited, please use the multi-function solenoid valve, because it eliminates the bypass and three manual valves and is convenient for online maintenance.
Power supply condition
1. According to the type of power supply, AC and DC solenoid valves are used respectively. Generally, AC power is convenient to use.
2. For voltage specifications, use AC220V and DC24V as much as possible.
3. The fluctuation of the power supply voltage is usually +10%~-15% for AC and ±10% for DC. If it is too poor, it must adopt voltage regulation measures or put forward special order requirements.
4. The rated current and power consumption should be selected according to the power supply capacity. It should be noted that the VA value is higher when the AC starts, and the indirect-lead solenoid valve should be preferred when the capacity is insufficient.
control precision
1. Ordinary solenoid valve can only open and close two positions. When the control precision is high and the parameter requirements are stable, please use multiple solenoid valves. Z3CF three normally open solenoid valves have three kinds of flow: micro start, full open and close.
2. Action time: refers to the completion time of the electric signal being turned on or off to the main valve. Only the multi-function solenoid valve can adjust the opening and closing time separately, which can not only meet the control accuracy requirements, but also prevent the water hammer from being damaged.
3. The leakage amount given on the sample is the common economic grade. If it is too high, please make a special order.
Second, reliability
life span
This item is not included in the factory test project and is a type test project. In order to ensure the quality, we should choose the famous brand products of regular manufacturers. The working life of the solenoid valve of Germany Lite LIT is generally more than 1 million times.
Working standard
It is divided into long-term work system, repeated short-time work system and short-time work system. The company's conventional products are long-term work, that is, the coil allows long-term power supply work. For long-time valve opening only when the time is closed, the normally open solenoid valve should be used. When used in short-term work and large batch sizes, special orders can be made to reduce power consumption.
working frequency
When the operating frequency requirement is high, the structure should preferably be a direct-acting solenoid valve, and the power supply is preferably exchanged.
Operational reliability
Strictly speaking, this test has not been officially listed in China's professional standards for solenoid valves. In order to ensure quality, brand-name products of regular manufacturers should be selected. In some occasions, there are not many movements, but the reliability requirements are very high, such as fire protection, emergency protection, etc., should not be taken lightly. Of particular importance, two pairs of dual insurance should also be used.
Third, security
Corrosive medium
Plastic solenoid valves and all stainless steels should be used; for strong corrosive media, isolation diaphragms must be used. Example CD-F.Z3CF. Neutral medium, it is also advisable to use copper alloy as the solenoid valve of the valve shell material. Otherwise, the rust will often fall off in the valve shell, especially in occasions with infrequent movement. Ammonia valves cannot be made of copper.
Corrosion-resistant is generally selected from stainless steel 304, 316, or plastic king tetrafluoro.
Explosive environment
The corresponding explosion-proof grade products must be selected. For outdoor installation or dusty occasions, waterproof and dustproof varieties should be used.
The nominal pressure of the solenoid valve should exceed the maximum gao working pressure in the tube. Select the explosion-proof solenoid valve, also called the imported explosion-proof solenoid valve
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