How to select pneumatic valves? What parameters are required for the selection of pneumatic control

Here are some well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Chaoda, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

The parameters required for the selection of pneumatic control valves include:

1. The type of medium (gas, liquid or steam).

2. The density macro state or specific gravity of the medium.

3. Pressure before and after the valve.

4. Flow rate and temperature.

The pneumatic control valve is to use compressed air as the power source, the cylinder as the actuator, and with the help of electrical valve positioners, converters, solenoid valves, position retention valves and other accessories to drive the valve, realize the switching or proportional adjustment, and receive the control signal of the industrial automation control system to complete the early adjustment of the pipeline medium: flow, pressure, temperature and other process parameters to shield the source.

Pneumatic control valves are characterized by simple control, fast response, and intrinsically safe conditions, without the need for additional explosion-proof measures.

This article introduces in detail the important elements of the selection of control valves; Part of the valve knowledge materials are excerpted from the American Vedun vton valve literature, by the original, if you think it will be helpful to you, please raise your noble hand, give the American Vedun vton valve a like.

In the field of industrial automation process control, the control valve is the final control element that changes the process parameters such as medium flow, pressure, temperature, and liquid level by accepting the control signal output by the regulation control unit, with the help of dynamic operation. It is generally composed of an actuator and a valve.

According to the driving mode, the common classification of control valves: imported pneumatic control valves, imported electric control valves, imported self-operated control valves, hydraulic control valves.

An important element in the selection of pneumatic control valves.

1. Select the pressure level of the valve according to the actual working condition pressure, the pressure before and after the valve.

2. Select and adjust the material of the valve according to the characteristics of the medium; If there is no corrosive medium, carbon steel or stainless steel is fine, if it is a corrosive medium, you need to choose stainless steel material or fluorine lining.

3. Select the caliber of the electric control valve according to the flow rate.

Fourth, select the locator, as well as explosion-proof or not, or explosion-proof level, protection level.

Sixth, the temperature of the root reed return medium is selected from the material of the Zhengdian valve body, such as low-temperature -196, low-temperature steel extension rod should be selected; For high temperatures, choose high-temperature materials.

Pneumatic control valves can be divided into two types: gas-closed and air-open according to different switching methods.

The gas-closed valve consists of a positive-acting actuator and a valve. When the input signal pressure is changed from the lower limit value to the upper value, and when the input signal pressure of the valve from the full open value is changed from the lower limit value to the upper value, the valve is fully closed to fully open.

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According to the stroke characteristics, the control valve can be divided into: linear stroke and angular stroke. Linear stroke includes: single-seat valves, double-seat valves, sleeve valves, cage valves, angle valves, three-way valves, diaphragm valves; Quarter-turn includes: butterfly valves, ball valves, eccentric rotary valves, and full-function ultra-light control valves.

According to the form of adjustment, it can be divided into: adjustment type, cutting type, adjustment cutting type;

According to the flow characteristics, it can be divided into: linear, equal percentage, parabolic, and fast open.

According to the valve action mode, it can be basically divided into: linear stroke and angular stroke.

a. The use and characteristics of the pneumatic control valve is a right-angle rotary structure, which is used with the valve positioner to achieve proportional adjustment; The V-shaped spool is most suitable for various adjustment occasions, with large rated flow coefficient, large adjustable ratio, good sealing effect, sensitive adjustment performance, small size, and can be installed vertically. It is suitable for controlling gas, steam, liquid and other media.

B. Features: It is a quarter-angle rotary structure, which is composed of V-shaped valve body, pneumatic actuator, positioner and other accessories; There is an intrinsic flow characteristic of approximately equal percentage; It adopts double bearing structure, small starting torque, good sensitivity and induction speed; Superior shearing ability.

c. The pneumatic piston actuator uses compressed air as the power source, and drives the crank arm to rotate 90 degrees through the movement of the piston to achieve automatic opening and closing of the valve. Its components are: adjusting bolts, actuator boxes, crank arms, cylinder blocks, cylinder shafts, pistons, connecting rods, cardan shafts.

d. The working principle of the pneumatic control valve: the pneumatic control valve is composed of an actuator and a regulating mechanism. The actuator is the thrust part of the regulating valve, which generates the corresponding thrust according to the magnitude of the control signal pressure and pushes the regulating mechanism to act.

The valve body is the regulating part of the pneumatic control valve, which is in direct contact with the regulating medium and regulates the flow of the fluid.