Common knowledge of the hottest solenoid valve

Common knowledge of solenoid valves

I. safety: failure to pay attention to safety will lead to disaster

1 Corrosive medium: Plastic King solenoid valve and all stainless steel should be selected; For strongly corrosive media, diaphragm type must be selected. Example cd-f. z3cf. For neutral medium, the solenoid valve with copper alloy as the valve shell material should also be selected, otherwise, rust chips often fall off in the valve shell, especially in the case of infrequent action. Ammonia valves cannot be made of copper

2. Explosive environment: products of corresponding explosion-proof grade must be selected, and waterproof and dustproof varieties should be selected for outdoor installation or dust-proof occasions

3. The nominal pressure of solenoid valve shall exceed the maximum working pressure in the pipe

II. Applicability: not applicable means spending money on things and adding trouble

1 Medium characteristics

1.1 different types of solenoid valves are selected for gas, liquid or mixed state. For example, ZQDF is used for air, zqdf-y is used for liquid, and zqdf-2 (or -3) is used for steam, otherwise it is easy to cause malfunction. ZDF series multi-function solenoid valve can be connected to air Liquid. It is best to inform the media status when setting, so that the installation user does not have to adjust it again

1.2 if the medium temperature is different from that of products of different specifications, otherwise the coil will burn out and the seal will be aged, which will seriously affect the service life

1.3 medium viscosity, usually below 50cst. If it exceeds this value, the diameter is greater than 15mm, and ZDF series multi-function solenoid valves are used for special orders. Set high viscosity solenoid valve with a diameter less than 15mm

1.4 when the medium cleanliness is not high, the recoil filter valve should be installed in front of the solenoid valve. When the pressure is low, the direct acting diaphragm solenoid valve can be used, such as cd-p

greatly reduce the cost

1.5 if the medium is directional circulation, and it is not allowed to reverse the flow of zdf-n and zqdf-n, it needs two-way circulation. Please make special requirements

1.6 the medium temperature should be within the allowable range of the solenoid valve

2. Pipeline parameters

2.1 select the valve port and model according to the requirements of medium flow direction and pipeline connection mode. For example, for switching from one pipe to two pipes, select Ca5 and Z3F for small diameter, and zdf-z1/2 for medium or large diameter. Another example is to control the confluence of two pipelines, please choose zdf-z2/1, etc

2.2 the nominal diameter is selected according to the flow and Kv value of the valve, which can also be the same as the inner diameter of the pipe. Please note that some manufacturers are not marked with Kv value, and the valve hole size is often smaller than the interface pipe diameter, so we must not delay things because of low price

2.3 working differential pressure

indirect pilot type can be selected if the minimum working differential pressure is above 0.04MPa; If the minimum working pressure difference is close to or less than zero, the direct acting type or step-by-step direct type must be selected

3. Environmental conditions

3.1 the maximum and minimum temperature of the environment should be selected within the allowable range. If there is an out of tolerance, special orders should be made

3.2 waterproof solenoid valve should be selected for occasions with high relative humidity in the environment and water drops and rain

3.3 special varieties, such as marine solenoid valves, should be selected for occasions with frequent vibration, turbulence and impact in the environment

3.4 for use in corrosive or explosive environments, hair corrosion resistance should be preferred according to safety requirements

3.5 if the environmental space is limited, please choose the multi-function solenoid valve, because it saves the bypass and three manual valves and is convenient for maintenance

4. Power conditions

4.1 according to the type of power supply, AC and DC solenoid valves are selected respectively. Generally speaking, the AC power supply is easy to access

4.2 24V shall be preferred for voltage specification as far as possible.

4.3 voltage fluctuation of power supply is usually +%10% for ac- 15%, DC is allowed to be about ±%10. If it exceeds the tolerance, voltage stabilization measures must be taken or special order requirements must be put forward

4.4 the rated current and consumed power should be selected according to the power capacity. It should be noted that the VA value is high during AC starting, and the indirect solenoid valve should be preferred when the capacity is insufficient

5. Control accuracy

5.1 ordinary solenoid valves only have two positions: on and off. When the control accuracy is required to be high and the parameters are required to be stable, please select multi position solenoid valves; Z3cf three position normally open solenoid valve has three flows: slightly open, fully open and closed; Zdf-z1/1 combined multi-function solenoid valve has four flows: full open, large open, small open and full open

5.2 action time: refers to the time from the electrical signal on or off to the completion of the main valve action. Only the patented multi-functional solenoid valve of the company can adjust the opening and closing time respectively, which can not only meet the requirements of control accuracy, but also prevent the damage of water hammer

5.3 leakage: the leakage value given on the sample is the common economic level. If it is too high, please make a special order

III. reliability: unreliability will damage the whole system

1. Working life. This item is not included in the factory test item, but belongs to the type test item. In order to ensure the quality, the famous brand products of regular manufacturers should be selected

2. Working system: divided into long-term working system, repeated short-term working system and short-term working system. Our company often, but these enterprises are mostly distributed in different regions. Our products are long-term working system, that is, the coil is allowed to work with power on for a long time. If the valve is opened for a long time and only closed for a short time, the normally open solenoid valve should be selected. When it is used in short-time working system and the batch is large, special orders can be made to reduce power consumption

3. Working frequency: when the action frequency is high, the direct acting solenoid valve should be preferred for the structure, and the AC should be preferred for the power supply

4. Action reliability

strictly speaking, this test has not been officially listed in the professional standard of solenoid valves in China. In order to ensure the quality, the famous brand products of regular manufacturers should be selected. In some cases, the number of actions is not much, but the reliability requirements are very high, such as fire protection, emergency protection, etc., which must not be taken lightly. It is particularly important to adopt two continuous double insurances

IV. Economy: uneconomical means that the thermal conductivity of investment plastics is relatively low, and the waste of energy and even life

it is one of the selected scales, but it must be economic on the basis of safety, applicability and reliability

economy is not only the price of the product, but also 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 whole automatic control system and even in the production line is very small. If you want to be cheap and choose incorrectly, the damage will be huge

in a word, economy not only refers to the product price, but also the performance price ratio and comprehensive cost price ratio of the product