Basic knowledge of solenoid valve
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Corrosive medium: The plastic king solenoid valve and all stainless steel should be used; for the strongly corrosive medium, the diaphragm type must be selected. Example CD-F.Z3CF.
Neutral medium, should also use copper alloy valve shell material for the solenoid valve, otherwise, the valve shell often rust off, especially infrequent occasions. Ammonia valves cannot use copper.
Explosive environment: The corresponding explosion-proof grade must be selected. For waterproof or dustproof installations in the open air or in dusty areas, the product should be selected. The nominal pressure of the solenoid valve should exceed the maximum working pressure in the pipe.
Second, applicability: does not apply to spend money to buy things, but also add trouble!
1. Media characteristics
1. Electromagnetic valves of different types are selected for quality gas, liquid state or mixed state. Example ZQDF is used for air, ZQDF-Y is used for liquid, and ZQDF-2 (or -3) is used for steam, otherwise it may cause malfunction. ZDF series multi-function solenoid valve can be connected to gas and liquid. It is best to state the media status at the time of subscription, and it is not necessary to install the user.
1.2 medium temperature products of different specifications, otherwise the coil will burn off, aging of the seal, seriously affecting life expectancy.
1.3 Medium viscosity, usually below 50 cSt. If it exceeds this value, the diameter is larger than 15mm and ZDF series multi-function solenoid valve is used for special orders. Path is less than 15mm high viscosity solenoid valve.
1.4 When the cleanliness of the medium is not high, a backflushing filter valve should be installed in front of the solenoid valve. In the case of low pressure, a direct-acting diaphragm type electromagnetic valve can be used as a CD-P.
1.5 If the medium is directional and does not allow backward flow, ZDF-N and ZQDF-N are required to use two-way flow, please make special requirements.
1.6 The medium temperature should be selected within the allowed range of the solenoid valve.
2. Pipeline parameters
2.1 Select the valve port and model according to the medium flow requirements and the pipe connection method. For example, for a switch from one pipe to two pipes, select CA5 and Z3F for small paths, and select ZDF-Z1/2 for medium or large paths. Another example is to control the convergence of two pipelines, please choose ZDF-Z2/1 and so on.
2.2 According to the flow and valve Kv value selected nominal diameter, but also 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 coveted and the price is low.
2.3 Working pressure difference The minimum operating pressure difference is above 0.04Mpa. Indirect piloting type can be used. The minimum operating pressure difference is close to or less than zero. It must use direct-acting type or step-by-step direct type.
3. Environmental conditions
3.1 The maximum and minimum temperatures of the environment shall be selected within the allowable range. If there is any excess error, special orders shall be made.
3.2 When the relative humidity in the environment is high and there are occasions such as water and rain, waterproof electromagnetic valve should be selected.
3.3 There are often vibrations in the environment, and bumps and impacts should be selected for special applications, such as marine solenoid valves.
3.4 The use of corrosive or explosive environments should be based on the safety requirements of the choice of resistance to corrosion.
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 easy to repair online.
4. Power conditions
4.1 According to the type of power supply, choose AC and DC solenoid valves respectively. In general, AC power is easy to use.
4.2 Voltage specification Use AC220V.DC24V as much as possible.
4.3 Power Supply Voltage Fluctuation Usually, the AC is selected between +% 10% and -15%, and the DC is allowed to be ± 10% or so. If there is an excess error, it is necessary to adopt a voltage regulator 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 value of VA is higher when the AC is started, and the indirect-conducting solenoid valve should be preferred when the capacity is insufficient.
5. Control accuracy
5.1 Ordinary solenoid valves only open and close two positions, please use multiple position solenoid valves when the control accuracy is high and the parameters require stable; Z3CF three normally open solenoid valves, with three kinds of flow: micro-open, full open and close; ZDF - The Z1/1 combination multi-function solenoid valve has four types of full-open, wide-open, small-open, and full-open.
5.2 Operation time: refers to the time when the electrical signal is turned on or off to the completion of the main valve action. Only the company's patented product multi-function solenoid valve can adjust the opening and closing time separately, not only meeting the control accuracy requirements, but also preventing water hammer damage.
5.3 Leakage The leakage value given on the sample is a common economic grade. If it is too high, please make a special order.
Third, reliability: not reliable will damage the entire system!
The working life, this item is not included in the factory test project, is a type test project. In order to ensure the quality should be selected from the regular manufacturers of brand-name products. 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 systems, that is, coils allow long-term power work. For long-term valve opening only short-term closure, you should use normally open solenoid valve. When used in a short-time work system and in large quantities, special orders can be made to reduce power consumption. Operating frequency: When the operating frequency is high, the structure should be a direct-acting solenoid valve, and the power supply should listen to the preferred communication. Action Reliability: Strictly speaking, this test has not been formally included in China's electromagnetic valve professional standards, in order to ensure quality should be selected from the regular manufacturers of brand-name products. In some cases, the number of operations is not large, but the reliability requirements are very high, such as fire protection, emergency protection, etc., must not be taken lightly. Of particular importance, it should also take two consecutive double insurance.
IV. Economics: No economy is a waste of money, energy or even life.
One of the scales it chooses, but it must be an economy that is based on safety, application, and reliability.
Economicality is not only the selling price of a product, but also priority is given to its function and quality, as well as the cost of installation, maintenance 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 the production line is negligible. If a small amount of money is spent on mistakes, the damage group is huge. In short, economics not only refers to the price of a product, but the ratio of the price of a product to the price of a comprehensive product.