Knowledge

Solenoid valve selection characteristics to use when using



First, security:
1. Corrosive medium: Plastic King solenoid valve and all stainless steel should be used; for strong corrosive medium, isolation diaphragm type must be used. Example CD-F. Z3CF. For neutral media, 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 casing, especially in occasions with infrequent movement. Ammonia valves cannot be made of copper.
2. Explosive environment: The corresponding explosion-proof grade products must be selected. For outdoor installation or dusty occasions, waterproof and dustproof varieties should be used.
3. The nominal pressure of the solenoid valve should exceed the maximum working pressure in the pipe.
Second, applicability:
1. Media characteristics
1.1 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 -3) is used for steam, otherwise it may cause malfunction. ZDF series multi-function solenoid valve can pass through gas and liquid. It is best to specify the media status when ordering, and the installation user does not have to adjust.
1.2 The medium temperature is different in specifications, otherwise the coil will burn out and the seal will age, which will seriously affect the life expectancy.
1.3 medium viscosity, usually below 50 cSt. If this value is exceeded, the ZDF series multi-function solenoid valve is used for special order with a diameter greater than 15mm. A high viscosity solenoid valve with a diameter of less than 15 mm.
1.4 When the media cleanliness is not high, the backflush filter valve should be installed in front of the solenoid valve. The low pressure mode can be used as a CD-P for direct acting diaphragm type solenoid valve.
1.5 If the medium is directional, and the backflow of ZDF-N and ZQDF-N is not allowed to flow in both directions, please make special requirements.
1.6 The medium temperature should be selected within the allowable range of the solenoid valve.
2. Pipeline parameters
2.1 Select the valve port and model according to the medium flow requirements and pipe connection. For example, for a pipe to switch to two pipes, choose 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.
2.2 According to the flow rate and valve Kv value, the nominal diameter is selected, and the inner diameter of the pipe can also be selected. Please note that some manufacturers do not have a Kv value, often the valve hole size is smaller than the interface diameter, and must not be greedy and low.
2.3 working pressure difference
The minimum working pressure difference above 0.04Mpa 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.
3. Environmental conditions
3.1 The highest and lowest temperatures of the environment should be selected within the allowable range. If there is an out-of-tolerance, special orders should be made.
3.2 When the relative humidity in the environment is high and there are water droplets and rain, etc., the waterproof solenoid valve should be selected.
3.3 In the environment, there are often vibrations, bumps and impacts, etc. Special varieties should be selected, such as marine solenoid valves.
3.4 In the case of corrosive or explosive environment, priority should be given to the use of corrosion resistance according to safety requirements.
3.5 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.
4. Power conditions
4. 1According to the type of power supply, AC and DC solenoid valves are used respectively. Generally, AC power is convenient to use.
4.2 For the voltage specification, use AC220V.DC24V as much as possible.
4.3 Power supply voltage fluctuations are usually +%10%.-15% for AC and ±10% for DC. If it is too poor, it must adopt voltage regulation measures or make special order requirements.
4.4 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 guided solenoid valve should be preferred when the capacity is insufficient.
5. Control accuracy
5.1 Ordinary solenoid valve only has two positions of opening and closing. 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;
The ZDF-Z1/1 combination multi-function solenoid valve has four flow rates: full open, large open, small open and full open.
5.2 Action time: refers to the completion time of the electric signal being turned on or off to the main valve. Only the patented multi-function solenoid valve of the company can adjust the opening and closing time separately, which can not only meet the control precision requirements, but also prevent the water hammer from being damaged.
5.3 leakage
The leakage amount given on the sample is the common economic grade. If it is too high, please make a special order.
Third, reliability:
1. Working life, this item is not included in the factory test project and belongs to the type test project. In order to ensure the quality, we should choose the famous brand products of regular manufacturers.
2, the work system: divided into long-term work system, repeated short-term work system and short-term work system three. The company's conventional products are long-term work, that is, the coil allows long-term power supply work. For the case where the valve opening is only closed for a short time, the normally open solenoid valve should be used. Used in short-term work and batch
When it is large, special orders can be made to reduce power consumption.
3. Working frequency: When the operating frequency is high, the structure should be a direct-acting solenoid valve, and the power supply should be preferred.
4, motion reliability
Strictly speaking, this test has not been officially listed in China's professional standards for solenoid valves. In order to ensure quality, we should select the famous brand products of regular manufacturers. 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. It is especially important to take two dual insurances.
Fourth, economic:
It is one of the scales chosen, but it must be based on a safe, applicable, and reliable economy.
Economics is not only the price of the product, but also the cost and quality of the product, as well as the cost of installing repairs and other accessories.
More importantly, the cost of a solenoid valve in the entire automatic control system in the entire automatic control system and even in the production line is negligible. If the image is small and cheap, it is huge to make a wrong group.
Installation precautions are as follows:
1. When installing, please pay attention to the arrow on the valve body should be consistent with the flow direction of the medium. Do not install in places where there is direct dripping or splashing. The solenoid valve should be installed vertically upwards.
2. The solenoid valve should ensure normal operation within the fluctuation range of 15%-10% of the rated voltage of the power supply voltage.
3. After the solenoid valve is installed, there must be no reverse pressure difference in the pipeline. It needs to be powered on several times to make it suitable for use.
4. The solenoid valve should be thoroughly cleaned before installation. The medium to be passed should be free of impurities. Install the filter in front of the valve.
5. When the solenoid valve fails or is cleaned, a bypass device should be installed to ensure the system continues to operate.