What is the principle of the electric low noise cage control valve?

1. The electric low-noise cage control valve is mainly designed to reduce the noise of compressible fluid, and in order to adapt to the throttling diffusion and expansion of gas, there are many symmetrical holes on the sleeve to reduce the pressure drop. The fluid channel is S-streamlined, and there is no guide wing that improves the smooth flow of fluid around the sleeve, so the pressure drop loss is small, the flow rate is large, and the noise is small.

2. 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 and using power operation in the field of industrial automation process control. 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.

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, 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.

Zhejiang Paiwo automatic control instrument products are still doing relatively well.

Hello, the general electric control valve is kept in the original switch position in the case of power failure, and will not be in the closed position, but there are manufacturers who specialize in making electric control valves that can be turned off and closed.

Electric valve: motor with double acting spool.

Use the process.

Electric valve: electric valve is generally a large pipe diameter, used in the flow of fluid, cut-off, flow, pressure and other control, circulation, cut-off control is called electric on-off valve (some can only be opened or closed, some can be stopped in the middle such as only a rough adjustment, such as %) for flow and pressure control is called electric control valve, what electric ball valve, electric disc valve, and what is called intelligent control valve, in fact, they are all electric valves.

The torque electric valve is large.

In the form of adjustment, the electric valve can roughly control the opening, and the principle is to stop during the rotation of the motor.

In the form of adjustment, the electric valve can roughly control the opening, and the principle is to stop during the rotation of the motor.

Control valves are divided into electric control valves, pneumatic control valves and hydraulic control valves.

The electric control valve is composed of two parts: electric actuator or pneumatic actuator and regulating valve. The latter has the characteristics of large flow capacity, small unbalance and stable operation, so it is usually especially suitable for occasions with large flow rate, high pressure drop and less leakage.

Flow-through capacity CV is one of the main parameters for selecting a control valve, and the definition of the flow capacity of the control valve is: when the control valve is fully open, the pressure difference between the two ends of the valve is, and the fluid density is 1g cm3, the flow rate of the flow diameter control valve per hour is called the flow capacity, also known as the flow coefficient, expressed in CV, the unit is T H, and the CV value of the liquid is calculated according to the following formula. Electric control valves are mainly used to regulate the flow, pressure and level of the medium.

According to the signal of the adjustment part, the opening of the valve is automatically controlled, so as to achieve the adjustment of medium flow, pressure and liquid level.

According to the flow capacity CV value of the table, the nominal diameter DN of the control valve can be determined.

The flow characteristics of the regulating valve are the relationship between the relative flow rate of the medium flowing through the regulating valve and its opening under the condition that the pressure difference between the two ends of the valve remains constant. There are three types of flow characteristics of control valves: linear, equal percentage and parabolic. The significance of the three note characteristics is as follows:

Linearity characteristics of electric control valves (linear).

The relative travel and flow of the linear properties are in a linear relationship. The change in flow rate caused by the change in the unit stroke is constant. When the flow rate is large, the relative value of the flow rate changes slightly, and when the flow rate is small, the relative value of the flow rate changes greatly.

Parabolic characteristics of electric control valves.

The flow rate varies proportionally to the two sides of the stroke, and generally has the intermediate characteristics of linearity and equal percentage characteristics.

From the analysis of the above three characteristics, it can be seen that in terms of its regulation performance, the equal percentage characteristics are the best, and its regulation is stable and the regulation performance is good. The parabolic characteristics are better than the adjustment performance of the linear characteristics, and any of the flow characteristics can be selected according to the requirements of different use occasions.

Equal percentage characteristics (logarithmic) of electric control valves

The relative stroke and the relative flow of the equal percentage characteristic are not in a straight line, and the change in flow caused by the change in the unit stroke at each point of the stroke is proportional to the flow rate at that point, and the percentage change in flow is equal. Therefore, its advantage is that the flow rate is small, and when the flow rate is large, the flow rate changes greatly, that is, it has the same adjustment accuracy in different openings.

It is connected by an electric actuator and a valve, and becomes an electric valve after installation and commissioning. The electric valve uses electric energy as the power to connect the electric actuator to drive the valve, and realize the opening and closing and adjusting of the valve. So as to achieve the purpose of switching or adjusting the pipeline medium.

The electric control valve is composed of hardware system and software system, and its hardware system mainly includes amplifier, brake disc, controllable switch and actuator. Amplifiers are generally cast from metal materials. It can amplify the programming language in the program system to make it an executable machine language, and then send it to the actuator to control the flow of the liquid and the proportion of pesticide moisture.

The controllable switch of the control valve is mainly responsible for the operation of the whole machine. Turning on the switch is only the first step in running the machine, turning off the switch can run the brake disc as soon as it stops the transport of liquid gases.

(1) PI regulation.

When the intelligent control valve accepts the transmitter signal for PI adjustment, the microcomputer first compares the transmitter signal with the given signal, calculates it according to the preset PI parameter law, and then sends the control signal to the actuator, and adjusts the valve until the signal is balanced. The PI adjustment function of the intelligent electric control valve is a low-cost, high-performance sampling control system, which does not need to use the conventional PID controller, but directly accepts the signal of the field transmitter to complete the work that is difficult to complete by the analog continuous control system. Some industrial objects have a long lag time (such as a furnace that controls the temperature), which will cause a large error and slow action of the system, and the use of microcomputer sampling and control can completely improve the control performance of low-pass.

2) Corrected the flow characteristics.

When the intelligent control valve is corrected for flow characteristics, the microcomputer in the servo amplifier should calculate the signal according to the preset characteristic parameters, so that the input signal and the valve displacement reach the required digital function relationship, and make nonlinear adjustment, which makes the selection and change of flow characteristics simple and easy, which is very important for the control system. Methods of changing the flow characteristics by changing the shape of the spool of a pneumatic single-seat control valve or changing the shape of the cam are lagging behind. In addition, quarter-turn valves such as butterfly valves cannot change the flow characteristics by changing the shape of the spool.

The use of an intelligent actuator can completely change this situation, because it is already an intelligent butterfly valve. Achievable changes in flow characteristics include: equal percentage—standard straight line; Standard straight line — equal percentage; Quick opening - standard straight line; Quick open – equal percentage; Parabola – standard straight line; Parabola — equal percentage.

3) Other features.

Such as the change of forward and reaction mode, fault location indication, diagnosis and alarm, electric braking, self-locking, etc.

The working principle of the electric proportional control valve: the electric proportional control valve is controlled by the opening angle of the valve in the control form. The control process is in the process of motor rotation, constantly feedback to the control unit with the linear resistance value, the control unit compares and judges according to the measured value and the feedback resistance value of the electric control valve, and sends out the control signal to stop the action immediately when it reaches the target position.

If you want to adjust the temperature, the temperature is high, reduce the flow, and thus reduce the temperature, which requires the thermocouple to feed back to the thermostat, and then the thermostat outputs a standard analog signal to the regulating valve, and the regulating valve automatically controls the opening of the valve according to this signal, so that the temperature is kept within the set temperature range. Of course, this temperature controller must be a smart meter with PID control function. The output signal of the control valve is generally the valve opening signal.

The working principle of the pneumatic valve is that 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.

General requirements: 1. The specifications and categories of pneumatic valves should meet the requirements of pipeline design documents.

2. The model of the pneumatic valve should indicate the national standard number requirements of the basis. If it is an enterprise standard, the relevant description of the model should be indicated.

3. The working pressure of the pneumatic valve requires the working pressure of the pipeline, and the working pressure that the valve can withstand should be greater than the actual working pressure of the pipeline without affecting the first floor; Under the condition of pneumatic valve closed, any side should be able to withstand the working pressure value of the valve without leakage; When the valve is opened, the valve body should be able to withstand the requirement of twice the working pressure of the valve.

4. The manufacturing standard of pneumatic valve should indicate the national standard number based on it, and if it is an enterprise standard, the enterprise document should be attached to the procurement contract. Pneumatic valve standards are divided into three specifications: national standard, American standard and Japanese standard.

5. The complete description of the pneumatic valve includes its specifications, materials, connection methods, and action modes (in which the action modes are divided into 1: double acting, 2: single acting).

Pneumatic valves are valves that are actuated by the help of compressed air. The compressed air is used to drive the movement of multiple groups of combined pneumatic pistons in the actuator, and the force is transmitted to the characteristics of the beam and the inner curve track, and the hollow core spindle is driven to rotate.

The compressed air disc is transmitted to each cylinder, the inlet and outlet positions are changed to change the direction of spindle rotation, and the cylinder combination can be adjusted according to the requirements of the rotation torque required by the load (valve) to drive the load (valve) to work.

The two-position five-way solenoid valve is usually used with the double-acting pneumatic actuator, the two-position is controllable: on-off, the five-way is five channels of ventilation, one of which is connected with the air source, two are connected with the air inlet and outlet of the external air chamber of the double-acting cylinder, and two are connected with the air inlet and outlet of the internal air chamber, and the specific working principle can refer to the working principle of the double-acting pneumatic actuator.

Due to the increasing number of control methods and means, there are many methods used to control pneumatic actuators in actual industrial life and industrial control. Pneumatic valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, slurries, oils, liquid metals and radioactive media.

Pneumatic ball valves are ball valves with pneumatic actuators. The specific classification of pneumatic ball valves includes: stainless steel pneumatic ball valves, plastic pneumatic ball valves, sanitary pneumatic ball valves, carbon steel pneumatic ball valves, two-way pneumatic ball valves, three-way pneumatic ball valves, and four-way pneumatic ball valves.

Working principle of pneumatic ball valve:

The pneumatic ball valve only needs to be operated by a pneumatic actuator with a 90-degree rotation of the air source and a small torque to close tightly. The completely equal body cavity provides a straight-through flow path with minimal resistance to the medium. It is generally considered that ball valves are most suitable for direct opening and closing.

The main feature of the ball valve is that it is compact in its own structure, easy to operate and maintain, and is suitable for general working media such as water, solvents, acids and natural gas, but also for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene. The ball valve body can be monolithic or combined.

Pneumatic ball valves are evolved from plug valves. It has the same rotational 90-degree action, the difference is that the body is a sphere, with circular through holes or channels through its axis. The ratio of the spherical surface to the channel mouth should be such that when the ball is rotated 90 degrees, the sphere should be presented at the inlet and outlet, thus cutting off the flow.

This type of valve can be installed in any position in the pipeline. Pneumatic ball valve is a ball valve with a pneumatic actuator, the execution speed of the pneumatic actuator is relatively fast, the fastest switching speed is seconds, so it is usually called pneumatic quick shut-off ball valve. Pneumatic ball valves are usually equipped with a variety of accessories, such as solenoid valves, air source treatment triplets, limit switches, positioners, control boxes, etc., to achieve local control and remote centralized control, in the control room can control the valve switch, no need to run to the scene or high altitude and danger to bring manual control, to a large extent to save human resources and time and safety.