Selection of solenoid valves 1
Solenoid valve selection should follow safety, reliability, and applicability in order Four major principles of safety and economy and six on-site working conditions requirements (i.e. diameter size, medium type, pressure level, power supply voltage, action mode, special functions).
Four principles
1. Safety: Failure to pay attention to safety will cause disaster!
1. Corrosive media: It is advisable to choose plastic solenoid valves and all stainless steel;for highly corrosive media, the isolation diaphragm type must be used. Example CD-F. Z3CF. For neutral media, it is also advisable to use solenoid valves with copper alloy as the valve shell material. Otherwise, rust chips often fall off in the valve shell, especially when the action is infrequent. Ammonia valves cannot be made of copper.
2. Explosive environment: Products with corresponding explosion-proof levels must be selected. Waterproof and dustproof varieties should be selected for outdoor installation or dusty occasions.
3. The nominal pressure of the solenoid valve should exceed the maximum working pressure in the pipe.
2. Applicability: Not applicable means spending money on things and causing trouble!
1. Medium characteristics
1.1 Different types of solenoid valves are selected for gas, liquid or mixed states, such as ZQDF for air, ZQDF-Y for liquid, ZQDF-2 (or -3) is used for steam, otherwise it may cause malfunction. The ZDF series multifunctional solenoid valve can pass through gas and liquid. It is best to regularly report the media status so that the installation user does not have to adjust it again.
1.2 Products with different specifications of medium temperature, otherwise the coil will burn out and the seals will age, seriously affecting the service life.
1.3 medium viscosity, usually below 50cSt. If it exceeds this value, if the diameter is larger than 15mm, use the ZDF series multi-function solenoid valve for special order. Order high viscosity solenoid valve with diameter less than 15mm.
1.4 When the medium cleanliness is not high, a backflush filter valve should be installed in front of the solenoid valve. When the pressure is low, a direct-acting diaphragm solenoid valve can be used, such as CD-P.
1.5 If the medium has directional circulation and no reverse flow is allowed, ZDF-N and ZQDF-N only need to use two-way circulation, 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 direction requirements and pipeline connection method. For example, for switching from one pipeline to two pipelines, choose CA5 and Z3F for small diameters, and choose ZDF-Z1/2 for medium or large diameters. If you want to control the convergence of two pipelines, please choose ZDF-Z2/1, etc.
2.2 Select the nominal diameter according to the flow rate and valve Kv value, or the same pipe inner diameter. Please note that some manufacturers do not mark the Kv value, and the valve hole size is often smaller than the interface pipe diameter. Do not make mistakes because of low prices.
2.3 Working pressure difference
If the minimum working pressure difference is above 0.04Mpa, the indirect pilot type can be selected;if the minimum working pressure difference is close to or less than zero, the direct-acting or step-by-step type must be selected Direct.
3. Environmental conditions
3.1 The maximum and minimum temperatures of the environment should be selected within the allowable range. If there is any deviation, a special order must be made.
3.2 In the environment where the relative humidity is high and there are water droplets and rain, etc., a waterproof solenoid valve should be selected.
3.3 In environments where there are often vibrations, bumps and impacts, special varieties should be selected, such as marine solenoid valves.
3.4 For use in corrosive or explosive environments, corrosion resistance should be given priority according to safety requirements.
3.5 If the environmental space is limited, please choose a multi-function solenoid valve, because it eliminates the need for bypass and three manual valves and facilitates online maintenance.
4. Power supply conditions
4.1 According to the type of power supply, AC and DC solenoid valves are selected respectively. Generally speaking, AC power is easy to access.
4.2 For voltage specifications, give priority to AC220V or DC24V.
4.3 Power supply voltage fluctuation is usually +%10%.-15% for AC, and ±%10 is allowed for DC. If it exceeds the tolerance, voltage stabilization measures must be taken or special ordering requirements must be made.
< div>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 during AC starting. When the capacity is insufficient, the indirect pilot solenoid valve should be preferred. 
