Common sense of fluid solenoid valve selection:
The selection of solenoid valves should follow the four principles of safety, applicability, reliability, and economy.
1. Security:
1. The nominal pressure of the solenoid valve should exceed the highest working pressure in the pipe.
2. Explosive environment must choose corresponding explosion-proof grade products, and waterproof and dustproof products should be selected for outdoor installation or dusty places.
3. For corrosive media, plastic solenoid valves and all stainless steel should be used. For strong corrosive media, solenoid valves with isolated sealed structures must be selected.
2. Applicability:
1. Medium characteristics:
1) The medium generally circulates in a directional direction, and reverse flow is not allowed. If there is a back pressure difference, a check valve should be installed to protect the normal operation of the solenoid valve.
2) The viscosity is usually below 20cSt. If it exceeds this value, the solenoid valve will be specially ordered. When the cleanliness is not high, a filter should be installed in front of the solenoid valve.
3) The temperature and pressure state of the medium should be consistent with the parameters of the solenoid valve selected, and the temperature of the medium should be selected within the allowable range of the solenoid valve, otherwise the coil will burn out and the seals will age, which will seriously affect the life.
2. Power conditions:
1) The rated current and power consumption should be selected according to the power supply capacity. It should be noted that the AV value is higher during AC starting, and the pilot solenoid valve should be preferentially used when the capacity is insufficient.
2) Power supply voltage fluctuation is usually +%10%.-15% for AC and ±10% for DC;
3. Environmental conditions:
1) For use in corrosive or explosive environments, solenoid valves should be selected according to safety requirements first.
2) In the environment where the relative humidity is high and there are water drops and rain, etc., a waterproof solenoid valve should be selected.
3) The maximum and minimum temperature of the environment should be selected within the allowable range of the selected product.
4. Pipeline parameters:
1) Choose the valve diameter and model according to the requirements of the medium flow direction and the pipe connection method. The nominal diameter can also be selected according to the flow rate and the valve Kv value, and the same pipe inner diameter can also be selected.
2) Pilot-operated solenoid valves can be selected if the minimum working pressure difference is above 0.04Mpa; direct-acting or step-by-step direct-acting solenoid valves must be used if the minimum working pressure is close to or less than zero.
3. Reliability:
1) In some occasions, the number of actions is not many, but the reliability requirements are high, such as fire protection, emergency protection, etc. You must not take it lightly and choose high-quality and reliable products.
2) Working life: the inspection items of life test and action reliability are not included in the factory test items in my country, but are type tests. In order to ensure the quality and life of the solenoid valve you buy, you should choose brand-name products from regular manufacturers.
4. Economy:
Economy is one of the selection criteria of solenoid valves, but it must be selected on the basis of safety, applicability and reliability. Economy is not only the price of the product, but also the function and quality, as well as the cost of installation, maintenance and other accessories. In short, economic efficiency does not only refer to product prices, but also product performance-price ratios and comprehensive cost-price ratios.