I. Security: 1. Corrosive media: the choice of plastic valve solenoid valve and stainless steel; for the strong corrosion of the media 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. 3, the environmental conditions 3.1 The maximum and minimum temperature of the environment should be selected within the allowable range, if any special orders for overcommitment proposed. 3.2 Ambient high relative humidity and rain drops and other occasions, the election should be waterproof solenoid valve 3.3 frequent vibrations in the environment, bumps and shocks and other occasions should choose a special breed, such as marine electromagnetic valve. 3.4 In a corrosive or explosive environment should give priority to use according to safety requirements corrosion resistance 3.5 If the environmental space is limited, please use multi-function solenoid valve, because it eliminates the need for bypass and three manual valves and easy online maintenance . 4, power conditions 4.1 According to the type of power supply, were selected AC and DC solenoid valve. In general AC power access convenience. 4.2 voltage specifications exhausted preferred AC220V, DC24V. 4.3 Power supply voltage fluctuations are usually used +10% AC, - 15%, DC allows ±% 10 or so, if ultra-poor, to take measures to stabilize the voltage or make special order requirements. 4.4 should be selected according to the power capacity of the rated current and power consumption. Should pay attention to AC starting VA value is higher, in the lack of capacity should be preferred indirect induction solenoid valve. 5, the control accuracy 5.1 ordinary solenoid valve only open and close two positions, high precision control parameters and parameters require stable multi-position solenoid valve; Z3CF three normally open solenoid valve, with micro-Kai, fully open and closed three Kinds of flow; ZDF-Z1 / 1 combination of multi-function solenoid valve with full open, big open, small open, full open four flow. 5.2 Operating time: refers to the electrical signal is turned on or off to the completion of the main valve action time, only the patented product multi-function solenoid valve can be adjusted on the opening and closing time, not only to meet the control accuracy requirements, but also to prevent water hammer damage. 5.3 Leakage The sample given on the value of leakage for the commonly used economic level, if too high, please make a special order. Third, the reliability: 1, working life, this is not included in the factory test project, a type test project. In order to ensure the quality of regular manufacturers should be selected brand-name products. 2, work standard: long-term work system, repeated short-term work system and short-term work system three. Conventional products are long-term work system, that coil allows long-term power work. For a long time to open the valve only a short time off, it should be used normally open solenoid valve. Used in short-time working system and the volume is very large, special orders can be made to reduce power consumption. 3, the working frequency: high frequency of operation, the structure should be preferred direct-acting solenoid valve, the power to listen to the preferred exchange. 4, the reliability of the operation Strictly speaking, this test has not yet officially included in the professional standards of our solenoid valve, to ensure the quality of the regular manufacturers should choose the brand-name products. In some occasions, the number of actions is not much, but the reliability requirements are very high, such as fire protection, emergency protection, must not be taken lightly. Particularly important, you should also take two double insurance. Fourth, the economy: Not economic is one of the criteria for the choice of funds, energy and even the loss of life, but must be based on the safe, applicable, reliable economic and economic not only the price of the product, but also give priority Considering its function and quality as well as the cost of installing maintenance and other accessories, more importantly, the cost of a solenoid valve in the entire automatic control system in the entire automatic control system or even the production line is negligible, if the cheaper choice Early damage caused by the group is huge. In short, economy refers not only to the product price, but to the product's cost performance to price ratio.