Electromagnetic directional valve discussed simply

ZF HYDRAULIC sharing: basic knowledge of solenoid valve:

 

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

 

 

1. Corrosive medium: plastic solenoid valve and stainless steel are preferred; For strongly corroded media, the isolation diaphragm must be chosen. Patients with CD - f. Z3CF. Neutral medium, also appropriate to choose copper alloy as the material of the valve shell electromagnetic valve, otherwise, the valve shell often has rust chip off, especially in the case of infrequent action. Ammonia valves are not made of copper.

 

 

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

 

 

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

 

 

Applicability: not applicable is equal to the cost of goods, but also add trouble!

 

 

1. Medium characteristics

 

 

1.1 different types of solenoid valves are selected for the quality 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. ZDF series multifunctional solenoid valves can be ventilated. Liquid. It is best to inform the state of the media when it is ordered, so that the installation user does not have to adjust the mode.

 

 

1.2 products of different specifications with different medium temperatures, otherwise the coil will burn up and the sealing parts will age, seriously affecting the life of the product.

 

 

1.3 medium viscosity, usually below 50cSt. If this value is exceeded, ZDF series multifunctional solenoid valves with a size greater than 15mm shall be used for special orders. Order high viscosity solenoid valve with a size less than 15mm.

 

 

1.4 when the cleanliness of the medium 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, such as cd-p, can be used.

 

 

1.5 if the medium is in directional flow, and the reverse flow of zdf-n and zqdf-n is not allowed, only two-way circulation is required, please make special requirements.

 

 

1.6 medium temperature shall be within the allowable range of solenoid valve.

 

 

2. Pipeline parameters

 

 

2.1 select valve outlet and model according to media flow requirements and pipe connection mode. For example, for switching from one pipe to two pipes, choose CA5 and Z3F for small sizes, and zdf-z1/2 for medium or large sizes. If you control the confluence of two pipes, please choose ZDF - z2/1, etc.

 

 

2.2 choose nominal through-diameter according to flow rate and valve Kv value, or the same pipe inner diameter. Please note that some manufacturers do not mark Kv value, often valve hole size less than the interface pipe diameter, do not covet low price and error.

 

 

2.3 working pressure difference

 

 

The indirect lead can be selected if the minimum working pressure difference is over 0.04Mpa. If the minimum operating pressure difference is close to or less than zero, the direct or step-by-step direct method must be adopted.

 

 

3. Environmental conditions

 

 

3.1 the maximum and minimum temperature of the environment shall be within the allowable range, and special orders shall be made if there is any deviation.

 

 

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

 

 

3.3 special varieties should be selected for vibration, turbulence and impact in the environment, such as Marine electromagnetic valve.

 

 

3.4 in corrosive or explosive environments, corrosion resistance shall be preferred according to safety requirements

 

 

3.5 if the environmental space is limited, please choose multi-functional solenoid valve, because it saves bypass and three hand operated valves and is convenient for online maintenance.

 

 

4. Power supply conditions

 

4. 1 according to the type of power supply, ac and dc solenoid valves are respectively selected. Generally speaking, ac power is easy to access.

 

 

4.2 for voltage specifications, AC220V and DC24V shall be preferred as far as possible.

 

 

4.3 the power supply voltage fluctuation is usually +%10%.-15% ac. Dc is allowed to + +% ~ %10.

 

 

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

 

 

5. Control accuracy

 

 

5.1 the general solenoid valve can only be opened or closed in two positions. When the control precision is high and the parameters are stable, please select multiple solenoid valves. Z3CF three-position normally open solenoid valve, with three flow rates: micro start, full open and close.

 

 

ZDF - z1/1 combined multi-function solenoid valve has four flow rates: full open, large open, small open and full open.

 

 

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

 

 

5.3 leakage

 

 

The leakage value given in the sample is the common economic grade. If it is too high, please make special order.

 

 

Reliability: unreliability will damage the whole system!

 

 

1. Service life, which is not included in the ex-factory test project, belongs to the type test project. In order to ensure quality, we should choose the famous brand products of regular manufacturers.

 

 

2. Working system: there are three types of long-term working system, repeated short-time working system and short-time working system. The company's conventional products are long - term working system, that is, the coil allows long - term power work. For long - time valve opening only a short - time closure, it is advisable to choose the usual open electromagnetic valve. Used in short-time working and batch

 

 

When large, special orders can be made to reduce power consumption.

 

 

3. Working frequency: when the required operating frequency is high, the structure should be optimized for the direct-acting solenoid valve and the power supply should be optimized for the communication.

 

 

4. Action reliability

 

 

Strictly speaking, this test has not been formally included in China's professional standards for electromagnetic valves, in order to ensure the quality of the selected manufacturers of brand-name products. Some occasions not many times of action, but high reliability requirements, such as fire, emergency protection, must not be taken lightly. Especially important, still should adopt two to use double insurance continuously.

 

 

Economy: no economy is a waste of money, energy and even life

 

 

It is one of the dimensions chosen, but it must be an economy based on security, 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, a solenoid valve in the whole automatic control system in the whole control system and even in the production line of the cost is very small, if the greed for small advantages and early wrong selection caused huge damage group.

 

 

In a word, economy not only refers to the product price, but also refers to the performance price of the product compared to the comprehensive cost price.

The above: Classification and definition of control valves