one. Safety: 1. Corrosive media: the choice of plastic valve solenoid valve and stainless steel; for the corrosive medium must use isolation diaphragm. Example CD-F. Z3CF. Neutral medium, copper alloy should also be used as the valve material of the solenoid valve, otherwise, the valve shell often rust off, especially when the action is not frequent. Ammonia valves can not use copper. 2. Explosive environment: you must choose the appropriate level of explosion-proof products, open-air installation or dust should be more occasions use waterproof, dustproof varieties. 3. Solenoid valve nominal pressure should exceed the maximum working pressure tube. II. Applicability: 1. Dielectric Characteristics 1.1 Solenoid valves of different types are used for 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 easy to cause malfunction. ZDF series of multi-function solenoid valve is available in the gas. Liquid. The best time to state the media state, the installation users do not have to adjust. 1.2 different medium temperature product specifications, or the coil will burn, seal aging, seriously affect the life of life. 1.3 Medium viscosity, usually below 50cSt. If more than this value, diameter greater than 15mm with ZDF series of multi-function solenoid valve for special order. Path less than 15mm set high viscosity solenoid valve. 1.4 Media cleanliness should be equipped with a recoil filter valve in front of the solenoid valve, the pressure is low fashion can choose direct acting diaphragm solenoid valve for example CD-P. 1.5 If the medium is directional and does not allow backflow ZDF-N and ZQDF-N need to be used in both directions, please make a special request. 1.6 medium temperature should be selected within the allowable range of the solenoid valve. 2, the pipeline parameters 2.1 According to the media flow requirements and pipeline connections choose the valve port and model. For example, the small diameter selection CA5 and Z3F for one pipe to two pipes, ZDF-Z1 / 2 for medium or large diameters. Another example is the control of the convergence of two pipelines, please choose ZDF-Z2 / 1. 2.2 According to the flow and the valve Kv value selected nominal diameter, but also optional with the pipe diameter. Please note that some manufacturers are not marked with Kv value, often the size of the valve hole is smaller than the interface diameter, must not be greedy price low and misleading. 2.3 Minimum working pressure differential Working pressure above 0,04Mpa is optional indirect pilot; minimum working pressure close to zero or less must be used direct or step-by-step direct type.