What factors need to be considered when selecting a control valve?

When making a specific choice, the following considerations can be made:

1) Spool shape structure.

It is mainly considered according to factors such as the selected flow characteristics and unbalanced forces.

2) Abrasion resistance.

When the fluid medium is a suspension containing a high concentration of abrasive particles, the internal material of the valve should be hard.

3) Corrosion resistance.

Due to the corrosive nature of the medium, try to choose a valve with a simple structure.

4) The temperature and pressure of the medium.

When the temperature and pressure of the medium are high and the change is large, the valve with small changes in temperature and pressure should be selected for the material of the spool and valve seat.

5) Prevent flash evaporation and cavitation.

Flash evaporation and cavitation are produced only in liquid media. In the actual production process, flash evaporation and cavitation will form vibration and noise, shorten the service life of the valve, so when selecting the valve, the valve should be prevented from flashing and cavitation.

6) The choice of manufacturers is also very important, good manufacturers have good products, recommend Shanghai Guardian Valve.

Here are some of the 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, Su Yan, 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.

To select the correct control valve, you can refer to the following scheme.

1. According to the process conditions, select the appropriate structural form and material. For example, the body material of the control valve is selected according to the characteristics of the medium.

2. According to the characteristics of the process object, select the flow characteristics of the Vton control valve.

3. According to the process operation parameters, select the appropriate Vton control valve caliber size. For example, choose the right caliber according to the flow rate.

4. According to the requirements of the process, select the required auxiliary devices.

5. Reasonable selection of executive agencies. The response speed of the actuator should be sufficient for the process.

Requirements for control stroke time: The actuator of the selected Vton control valve should be able to meet the requirements of the valve stroke and the leakage level of the process. In some cases, such as the selection of pressure regulating valves (including vent valves), the actual possible pressure difference should be considered for appropriate amplification, that is, the actuator is required to provide a large force.

Otherwise, when there is an abnormal situation in the process, the actual pressure difference between the front and back of the regulating valve is large, and there will be a danger that it cannot be closed or opened.

Selection of CV3000 control valve.

When the differential pressure is low and the leakage is more stringent, the CV3000-HTS single-seat control valve can be selected; If the pressure difference is large and the leakage is small, the CV3000-HSC cage single-seat control valve can be selected; For high-pressure differential fluids, in order to prevent cavitation and noise, CV3000-HCB cage control valve and CV3000-HCN low-noise cage control valve can be used; There are CV3000-HLS small-diameter single-seat control valves for small flow adjustment, and CV3000-HTSW bellows sealed single-seat control valve can be selected for corrosive and toxic media that are strictly forbidden to leak. In addition, depending on the site conditions, electric actuators (explosion-proof construction optional) can be optionally selected, and the CV3000-DHSC explosion-proof electric cage single-seat control valve and CV3000-DHCB electric cage control valve can meet your requirements in this regard.

In the field of industrial automation process control, the control valve, also known as 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. It is generally composed of an actuator and a valve. According to the stroke characteristics, the control valve can be divided into linear stroke and angular stroke; According to the power used by the actuator, it is divided into three types: linear characteristics, equal percentage characteristics and parabolic characteristics according to its functions and characteristics.

The control valve is suitable for air, water, steam, various corrosive media, mud, oil and other media. English name: Control Valve, the tag usually starts with FV.

Commonly used classification of control valves: pneumatic control valves, electric control valves, hydraulic control valves, self-operated control valves.

Classified by use and function.

a.Two-position valve: mainly used to close or turn on the medium;

b.Control valve: mainly used in the control system. When selecting a valve, it is necessary to determine the flow characteristics of the regulating valve;

c.Diverter valves: used for dispensing or mixing media;

d.Shut-off valve: Usually refers to a valve with a leakage rate of less than 1 in 100,000.

Classified by main parameters.

1 Classification by pressure.

1) Vacuum valve: the working pressure is lower than the standard atmospheric pressure;

2) Low pressure valve: nominal pressure pn;

3) Medium pressure valve:;

4) High pressure valve: usually PN22, PN32;

5) Ultra high pressure valve: PN 100MPa.

2 Classified by medium operating temperature.

1) High temperature valve: T>450;

2) Medium temperature valve: 220 t 450;

3) Normal temperature valve: 40 t 220; Cryogenic valve: 200 t 40.

Commonly used taxonomies.

This classification method is divided according to principle, function and structure, and is currently the most commonly used classification method at home and abroad. It is generally divided into nine categories:

Linear pneumatic control valve.

1) Single-seat control valve;

2) Double-seat control valve;

3) sleeve control valve;

4) Angle control valve;

5) Three-way control valve;

6) Diaphragm valve;

7) Butterfly valve; 8) Ball valve;

9) Eccentric rotary valve. The first six are linear strokes, and the last three are angular strokes.

These nine products are also the most basic products, also known as normal products, base products, or standard products. All kinds of special products and special products are improved and varied on the basis of these nine types of products.

<> nearly 100 years from the beginning of the 20th century to the present, the control valve is still at the level of the first generation of products. Its characteristics are: single-seat valves, double-seat valves, and sleeve valves at the level of the sixties and seventies of the 20th century as the leading products; This generation of products is not complete in function, and has to rely on expanding product varieties and variants to adapt to various occasions, resulting in a wide variety of specifications, and particularly high requirements for the use, calculation, selection, adjustment, maintenance, and spare parts of control valves; Poor reliability, many problems when using; It's bulky.

Nowadays, the more popular CV3000 and fine small valves are 30% more than the traditional old products: the weight is reduced by 30%; 30% drop in height; 30% increase in flow coefficient. But they did not bring a qualitative breakthrough, but only improved the traditional products.

The second-generation product should have a qualitative breakthrough in terms of reliability, function and weight. Its characteristics are: the full-power Zhensuineng ultra-light control valve replaces many products with poor reliability, incomplete functions and very bulky products, and replaces the leading products of the first generation of single-seat valves, double-seat valves and sleeve valves, and becomes the leading products of the second generation; The electronic electric full-function ultra-light travel control valve gradually replaces the traditional combination of "pneumatic valve + electrical valve positioner + air source" that has to be adopted due to the poor reliability of the original actuator.

From the perspective of external peibu, the second generation of products should have the characteristics of lightweight, miniaturization and instrumentation.

Its outstanding features are intelligent, and meet the requirements of the fieldbus, and the characteristics of the application are: interface with the computer; Self-diagnosis improves reliability and further reduces the failure rate. Modify the characteristic curve of the valve, thereby changing the regulating quality of the valve; The varieties of rotary lobe pump control valves and the requirements for the use of control valves are further simplified; In terms of indicators, it meets the requirements of modern industry to reach a new level of performance, such as some demanding requirements for control valves in new processes and systems introduced by some industrial sectors.