High temperature ball valve is a commonly used device for controlling the flow rate of media. It can be used to control the flow rate, pressure, and temperature of media and is widely used in various industrial applications.
1. The structure of a high-temperature ball valve is simple, consisting of a ball body, valve body, valve stem, valve seat, valve cover and other components. The ball body is made of steel or stainless steel, the valve body is made of cast iron, cast steel or stainless steel, the valve stem is made of steel or stainless steel, the valve seat is made of cast iron, cast steel or stainless steel, and the valve cover is made of cast iron, cast steel or stainless steel.
2. The working principle of a high-temperature ball valve is that when the medium passes through the valve body, the ball will be pushed by the pressure of the medium, thereby changing the opening degree of the valve and controlling the flow rate, pressure, and temperature of the medium.
3. High temperature ball valves have many advantages. Firstly, their structure is simple and easy to install and maintain, which can save time and cost in installation and maintenance.
4. Secondly, high-temperature ball valves have a large flow rate and can control a large amount of media to meet different operating conditions.
5. In addition, the high-temperature ball valve has low noise, which can meet different working conditions and improve work efficiency.
6. In addition, high-temperature ball valves have strong corrosion resistance and can be used in various media such as water, oil, gas, etc. They have strong corrosion resistance and can meet different working conditions.
7. Finally, high-temperature ball valves have good wear resistance, which can meet different working conditions and extend their service life.
8. In summary, high-temperature ball valves are commonly used devices for controlling medium flow rates. They have the characteristics of simple structure, high flow rate, low noise, strong corrosion resistance, can be used for various media, and have good wear resistance. They can be widely used in various industrial applications.
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Low temperature ball valve is a commonly used device for controlling the flow rate of media, which can be applied to low-temperature or ultra-low temperature media such as -50 ℃, -110 ℃, and -196 ℃. It can control the flow rate and cut off the media, and is widely used in various industries such as LNG systems, cryogenic systems, military, aerospace, etc.
1. The working principle of low-temperature ball valve is to open or close the ball by rotating it 90 °, which has the characteristics of short stroke and rapid opening and closing.
2. The structure of low-temperature ball valves is simple, easy to install and maintain, which can save time and cost in installation and maintenance.
3. Low temperature ball valves have a large flow rate and can control a large amount of media to meet different operating conditions.
4. Low temperature ball valves have low noise, which can meet different working conditions and improve work efficiency.
5. Low temperature ball valves have strong corrosion resistance and can be used in various media such as water, oil, gas, etc. They have strong corrosion resistance and can meet different working conditions.
6. Low temperature ball valves have good wear resistance, which can meet different working conditions and extend their service life.
7. In addition, the low-temperature ball valve has good sealing performance, which can effectively prevent the leakage of the medium and ensure the safety of operation.
8. In addition, the operation of low-temperature ball valves is flexible. It can adjust the opening degree of the valve according to different working conditions, thereby controlling the flow rate, pressure, and temperature of the medium.
9. In short, low-temperature ball valves are commonly used equipment for controlling medium flow rates. They have the characteristics of simple structure, high flow rate, low noise, strong corrosion resistance, can be used for various media, good wear resistance, good sealing performance, and flexible operation. They can be widely used in various industrial occasions.
Insulated ball valve is a special type of ball valve that has good insulation performance. By conveying high-temperature steam or high-temperature heat transfer oil through the jacket layer, it can effectively prevent the loss of heat energy, achieve insulation effect, and make the medium less prone to solidification and crystallization.
1. The structure of the insulated ball valve is simple, consisting of a ball body, valve seat, valve stem, valve disc, valve core, valve cover and other components. The sphere is made of high-temperature resistant insulation material, which has good insulation performance and can effectively prevent the loss of heat energy, thereby saving energy.
2. The working principle of the insulated ball valve is that when the handwheel on the valve stem rotates, the valve stem will drive the valve disc to rotate, thereby changing the opening degree of the valve, controlling the flow rate of the fluid, and adjusting the flow rate and pressure.
3. The advantage of insulated ball valve is that it has good insulation performance, which can effectively prevent the loss of heat energy and save energy; It has a simple structure, easy operation, and convenient maintenance; It has high adjustment accuracy and can meet different working conditions requirements; It has good sealing performance, which can effectively prevent air leakage and improve work efficiency.
4. Insulated ball valves are widely used in industries such as petroleum, chemical, power, metallurgy, pharmaceuticals, and food. They can meet different working conditions and are an efficient and reliable regulating valve.
5. Insulated ball valve is a commonly used regulating valve, which has good insulation performance and can effectively prevent the loss of heat energy, thereby saving energy. It has a simple structure, easy operation, convenient maintenance, high adjustment accuracy, and good sealing performance, and is widely used in industries such as petroleum, chemical, power, metallurgy, pharmaceuticals, and food.
6. The valve body of the stainless steel insulated ball valve is made of 304 or 316 material, which has anti-corrosion effect. The structure consists of a ball, a valve seat, a valve stem, a valve disc, a valve core, a valve cover and other components. The sphere is made of high-temperature resistant insulation material, which has good insulation performance and can effectively prevent the loss of heat energy, thereby saving energy. The valve seat is made of high-strength metal material, which has good corrosion resistance and can work stably for a long time. The valve stem is made of high-strength metal material, which has good corrosion resistance and can work stably for a long time. The valve disc is made of high-temperature resistant metal material, which has good corrosion resistance and can work stably for a long time. The valve core is made of high-temperature resistant metal material, which has good corrosion resistance and can work stably for a long time. The valve cover is made of high-temperature resistant metal material, which has good corrosion resistance and can work stably for a long time.
7. The working principle of the insulated ball valve is that when the handwheel on the valve stem rotates, the valve stem will drive the valve disc to rotate, thereby changing the opening degree of the valve, controlling the flow rate of the fluid, and adjusting the flow rate and pressure. The advantage of insulated ball valve is that it has good insulation performance, which can effectively prevent the loss of heat energy and save energy; It has a simple structure, easy operation, and convenient maintenance; It has high adjustment accuracy and can meet different working conditions requirements; It has good sealing performance, which can effectively prevent air leakage and improve work efficiency.
The precautions for using insulated ball valves include:
1. When installing insulated ball valves, attention should be paid to the installation direction of the valve body to ensure the correct installation of the valve;
2. When installing insulated ball valves, attention should be paid to the installation position of the valve body to ensure the correct installation of the valve;
3. When installing insulated ball valves, attention should be paid to the installation and fastening of the valve body to ensure the correct installation of the valve;
4. When installing insulated ball valves, attention should be paid to the smooth installation of the valve body to ensure the correct installation of the valve;
5. When installing insulated ball valves, attention should be paid to the cleanliness of the valve body to ensure the correct installation of the valve;
6. When installing insulated ball valves, attention should be paid to the stable installation of the valve body to ensure the correct installation of the valve.
Insulated ball valve is an efficient and reliable regulating valve with good insulation performance, which can effectively prevent heat loss and save energy. It is widely used in industries such as petroleum, chemical, power, metallurgy, pharmaceuticals, and food, and can meet different working conditions. However, when using insulated ball valves, attention should be paid to installation specifications to ensure the correct installation of the valve, as well as regular inspection and maintenance to ensure the normal operation of the valve.
Flange ball valve is a commonly used switch regulating valve, which has the advantages of simple structure, easy operation, reliable sealing, and small flow loss. It is widely used in industries such as petroleum, chemical, power, metallurgy, pharmaceuticals, and food. The structure of a flanged ball valve consists of a valve body, valve stem, valve seat, valve disc, valve cover, valve core, valve shaft, valve seat gasket, valve stem gasket, valve stem handle, etc.
1、 The working principle of flange ball valve is:
The opening and closing component is a circular sphere that can be opened or closed by rotating 90 degrees. When the valve stem handle rotates, the valve stem drives the valve core to move up and down, thereby changing the opening degree of the valve disc and controlling the flow rate of the fluid, thus achieving the purpose of regulating the flow rate.
2、 Installation requirements for flange ball valves:
1. Attention should be paid to the installation position of the valve body during installation to ensure the correct installation of the valve;
2. During installation, attention should be paid to the tightening of the valve body to ensure the correct installation of the valve;
3. During installation, attention should be paid to the flatness of the valve body to ensure the correct installation of the valve;
4. During installation, attention should be paid to the cleanliness of the valve body to ensure the correct installation of the valve;
5. Attention should be paid to the stable installation of the valve body during installation to ensure the correct installation of the valve.
3、 Maintenance and upkeep of flanged ball valves:
1. Regularly check the sealing of the valve body to ensure its normal operation;
2. Regularly check the lubrication condition of the valve body to ensure the normal operation of the valve;
3. Regularly inspect the damage of the valve body to ensure its normal operation;
4. Regularly check the cleanliness of the valve body to ensure its normal operation;
5. Regularly inspect the installation of the valve body to ensure its proper functioning.
In short, flange ball valve is a commonly used regulating valve, which has the advantages of simple structure, easy operation, reliable sealing, and small flow loss. It is widely used in industries such as petroleum, chemical, power, metallurgy, pharmaceuticals, and food. However, when using it, attention should be paid to installation specifications to ensure the correct installation of the valve, as well as regular inspection and maintenance to ensure the normal operation of the valve.
Hard sealed ball valve is a type of valve with good sealing performance. It adopts hard sealing technology and has three characteristics: high temperature resistance, high pressure resistance, and wear resistance. It can effectively prevent medium leakage and has good corrosion resistance, which can meet the requirements of various working conditions.
1. The working principle of a hard sealed ball valve is that when the valve stem rises, the hard sealing structure composed of the sealing ring and piston between the valve ball and the valve seat will be squeezed, causing the valve to close; When the valve stem descends, the hard sealing structure composed of the sealing ring between the valve ball and the valve seat and the piston will be stretched, causing the valve to open and achieve fluid control.
2. The structure of a hard sealed ball valve consists of a valve body, valve ball, valve stem, valve seat, sealing ring, piston, etc. The valve body consists of two parts, the upper part is the valve ball chamber and the lower part is the valve seat chamber. The valve ball chamber is equipped with a valve ball, and the valve seat chamber is equipped with a valve seat. The valve ball and the valve seat are connected by a hard sealing structure composed of a sealing ring and a piston. The valve stem is supported by a bearing on the upper part of the valve body, and the upper end of the valve stem is connected to the valve ball. The lower end of the valve stem is connected to the handwheel outside the valve body. The up and down movement of the valve stem is controlled by the rotation of the handwheel, thereby controlling the opening and closing of the valve.
3. Hard sealed ball valves have excellent sealing performance, which can effectively prevent the leakage of media, have good corrosion resistance, can effectively resist the erosion of corrosive media, have good operational performance, can achieve rapid opening and closing, have a compact structure, can effectively reduce the space occupation of pipeline systems, have good wear resistance, can effectively resist the wear of media, have good reliability, and can effectively ensure the safe operation of pipeline systems.
Soft sealed ball valve is a commonly used control valve, which consists of a ball body, valve body, valve stem, soft seal, handwheel, etc. The sphere is fixed by the valve body and valve stem, and a handwheel is installed on the valve stem. The handwheel drives the sphere to rotate through the valve stem, thereby controlling the opening and closing of the valve. The soft seal is composed of the space between the valve body and the valve stem. When the valve stem rotates, the soft seal will change shape, thus playing a sealing role.
The advantages of soft sealed ball valves are: they have good sealing performance and can effectively prevent liquid leakage; Its structure is simple and easy to install and maintain; Its operation is flexible and can achieve remote control; Its traffic loss is small, which can effectively improve the efficiency of the system.
Characteristics of Soft Seal Ball Valve:
1. It has good sealing performance and can effectively prevent liquid leakage;
2. It has good corrosion resistance and can effectively prevent corrosion;
3. It has good operational performance and can effectively improve work efficiency;
4. It has good maintainability and can effectively reduce maintenance costs.
Structure of soft sealed ball valve:
A soft sealed ball valve consists of a ball body, valve body, valve stem, soft seal, handwheel, and other components. The sphere is fixed by the valve body and valve stem, and a handwheel is installed on the valve stem. The handwheel drives the sphere to rotate through the valve stem, thereby controlling the opening and closing of the valve. The soft seal is composed of the space between the valve body and the valve stem. When the valve stem rotates, the soft seal will change shape, thus playing a sealing role.
The principle of soft sealed ball valve:
The working principle of a soft sealed ball valve is that when the valve stem rotates, the ball also rotates, thereby changing the opening and closing state of the valve. When the valve stem rotates, the soft seal will also change shape, thus playing a sealing role.
The standard for soft seal ball valves:
The standards for soft sealed ball valves mainly include GB/T 12237-2005 “Ball Valves for Petroleum and Chemical Industry”, GB/T 12238-2005 “Butterfly Valves for Petroleum and Chemical Industry”, GB/T 12239-2005 “Check Valves for Petroleum and Chemical Industry”, GB/T 12240-2005 “Globe Valves for Petroleum and Chemical Industry”, etc.
Soft sealed ball valves have a wide range of applications and can be used in industries such as petroleum, chemical, thermal, power, metallurgy, mining, environmental protection, and water treatment to control parameters such as flow rate, pressure, and temperature of various media.
In short, soft sealed ball valves are efficient, reliable, and structurally simple control valves. They have a wide range of applications and can meet the needs of various industries. They are a very useful control valve.
Eccentric hemispherical valve is a commonly used control valve, whose main function is to control the flow rate and pressure of fluids. Its working principle is to control the flow rate and pressure of the fluid by rotating the hemispherical valve core, thereby achieving fluid control and regulation. Below, we will provide a detailed introduction to the working principle, structural characteristics, and application fields of eccentric hemispherical valves.
1、 Working principle
The working principle of an eccentric hemispherical valve is to control the flow rate and pressure of the fluid by rotating the hemispherical valve core. When the hemispherical valve core rotates, fluid will flow into the interior of the hemispherical valve core from the inlet of the valve, and then flow out through the outlet of the hemispherical valve core. The rotation angle of the hemispherical spool determines the flow rate and pressure of the fluid, so fluid control and regulation can be achieved by controlling the rotation angle of the hemispherical spool.
2、 Structural characteristics
The structural characteristics of eccentric hemispherical valves mainly include the following aspects:
1. Valve body: The valve body of an eccentric hemispherical valve usually adopts a spherical structure, with one side of the sphere being hemispherical and the other side being circular. The hemispherical side is the inlet of the valve, and the circular side is the outlet of the valve.
2. Hemisphere valve core: The hemisphere valve core is the core component of an eccentric hemisphere valve, and its shape is similar to a hemispherical bowl. One side of the hemispherical valve core is convex, and the other side is concave. The protruding side corresponds to the hemispherical side of the valve body, and the concave side corresponds to the circular side of the valve body.
3. Transmission device: The transmission device of the eccentric hemispherical valve usually adopts manual, electric or pneumatic transmission device. Manual transmission devices usually use handwheels or handles, electric transmission devices usually use motors and reducers, and pneumatic transmission devices usually use pneumatic actuators.
4. Sealing structure: The sealing structure of eccentric hemispherical valves usually adopts soft sealing or metal sealing. Soft seals are usually made of materials such as rubber or polytetrafluoroethylene, while metal seals are usually made of materials such as stainless steel or titanium alloy.
3、 Application Fields
Eccentric hemispherical valves are widely used in industries such as petroleum, chemical, metallurgical, power, and water treatment, mainly for controlling fluid flow and pressure. Its advantages include simple structure, easy operation, good sealing, strong corrosion resistance, and long service life. In the petroleum and chemical industry, eccentric hemispherical valves are commonly used to control high temperature, high pressure, and highly corrosive media such as acids, alkalis, salts, etc. In the water treatment industry, eccentric hemispherical valves are commonly used to control the flow and pressure of media such as sewage and wastewater.
In short, eccentric half globe valve is a commonly used control valve, which works by rotating the half globe valve core to control the flow and pressure of fluid. Its structural characteristics are simple, easy to operate, good sealing, strong corrosion resistance, and long service life. It is widely used in various fields, mainly in industries such as petroleum, chemical, metallurgy, power, and water treatment.
1. Design: Based on the usage requirements and working environment, design the structure, materials, dimensions, and other parameters of the valve. During the design process, factors such as valve functionality, sealing performance, and pressure resistance need to be considered. 2. Material selection: Select suitable materials for manufacturing according to design requirements. Common valve materials include cast iron, cast steel, stainless steel, copper alloy, etc. 3. Material processing: According to the design drawings, the selected materials are processed through cutting, forging, casting and other processing techniques to manufacture various components of the valve. 4. Assembly: Assemble the processed components, including installing the valve body, valve cover, valve stem, valve seat, sealing ring, etc. During the assembly process, attention should be paid to the precision of component fitting and installation sequence. 5. Inspection: Conduct various inspections on the assembled valve, including visual inspection, dimensional testing, sealing performance testing, etc. Ensure that the quality of the valve meets the design requirements.
6. Surface treatment: According to the needs, the valve should be surface treated, such as spraying anti-corrosion paint, galvanizing, etc., to improve the corrosion resistance of the valve.
7. Packaging and factory delivery: Pack the manufactured valves and sell or transport them to the place of use.
It should be noted that the manufacturing process of valves may vary depending on different types of valves, such as ball valves, butterfly valves, gate valves, etc. The specific manufacturing process also needs to be adjusted and optimized according to different types of valves.
Electric vacuum ball valve is a valve suitable for connecting or cutting off the flow of medium in vacuum systems. It adopts a rotary electric and electronic regulating valve drive device, which can achieve valve opening, closing or intermediate position control through the switching of external power supply (manually operated or computer-controlled) or external input signals. Electric vacuum ball valves have excellent sealing performance and low leakage rate, which can effectively ensure gas quality, improve production efficiency, and have the characteristics of fast opening and closing, which can adapt to high requirements for valve opening and closing speed.
The electric vacuum ball valve consists of an electric actuator and a ball valve body. The electric actuator includes an electric motor, limit switch, control circuit, and other parts. The control circuit is used to achieve the start stop and forward/reverse rotation of the electric motor; The ball valve body is composed of valve body, valve ball, sealing ring and other components. When the electric actuator is started, the motor drives the valve ball to rotate, thereby opening or closing the medium channel.
Electric vacuum ball valves are widely used in multiple industries. In the petrochemical industry, it is mainly used in gas separation, transportation, and storage processes; In the pharmaceutical industry, it is mainly used in sterile production environments, which can effectively prevent external pollutants from entering the production environment, ensuring the quality and safety of drugs. In addition, electric vacuum ball valves are widely used in vacuum systems in industries such as power, steel, paper, food, beverage, medicine, and environmental protection.
GUD electric high vacuum ball valve is driven by an electric device to open and close the valve stem and ball core, achieving the connection or disconnection of the medium flow in the vacuum (pressure) system pipeline. Applied in the fields of vacuum, dairy products, wine industry, biotechnology, food, pharmaceuticals, beverages, cosmetics, and chemical industry.
It should be noted that different electric vacuum ball valve products may have different technical parameters, such as valve leakage rate, applicable temperature, closing time, operating pressure range, etc. Therefore, when selecting and using, it is necessary to choose according to specific application scenarios and requirements.
In summary, electric vacuum ball valves are powerful and widely used valve products that can effectively control the flow of media in vacuum systems, improve production efficiency, and ensure production safety.
Categories
Preliminary selection of valves
What is the purpose of valve preliminary selection?
The selection of valve selection is often not achieved overnight, especially for beginners. In order to calculate the discharge coefficient, estimate the noise, etc. It is necessary to select the structure of the valve body to obtain some calculation parameters. If the calculation results do not meet the requirements, the valve type should be re selected. The actuator, the form of upper valve cover and the material of valve internals can be ignored temporarily.
What is the basis of primary valve type selection?
According to the nature of the medium, process parameters, use requirements of the primary selection of valve type.
1、 Which of the following media properties should be specified
1. General fluid;
2. High viscosity, suspended solids, fibrous and other fluids;
3. Toxic or expensive fluids;
4. Corrosive fluid.
2、 Which of the following types of process parameters should be specified
1. Low pressure, small pressure difference and large flow rate;
2. Medium pressure or low pressure, large pressure difference;
3. High temperature, high pressure and high pressure difference;
4. Temperature and temperature difference;
3、 The use requirements are one or more of the following
1. The leakage is small or cut-off is required;
2. Good stability and convenient maintenance;
3. Requirements for the weight, size and volume of the control valve;
4. Action speed requirements.
What should be known about valve control medium? What else should be mastered about process parameters?
The specific name, property and main physicochemical parameters of controlled medium, density, kinematic viscosity, molecular weight, thermodynamic critical pressure, valve inlet temperature, saturated vapor pressure, specific heat capacity ratio, compression coefficient, etc. Process parameters should be generally understood: flow, pressure before valve, pressure after valve, inlet temperature, etc.
What else should be mastered about valve service conditions?
It is also necessary to master the piping form of the control valve, the pipe diameter before and after the valve, and the system resistance. The main parameters and main interference factors should be understood in the type and characteristics of the automatic control object, and the leakage and stability requirements should be understood in the regulation performance requirements.
Categories
How to choose valve positioner correctly
How do valve positioners and control valves form a loop?
The valve positioner is the main accessory of the control valve. It is used with the regulating valve to receive the output signal of the regulator, and then control the regulating valve with its output signal. After the regulating valve acts, the displacement of the valve stem is fed back to the valve positioner through the unloading device. Therefore, this kind of positioner and the regulating valve form a closed-loop loop loop.
How to classify valve positioners according to structure and working principle?
Valve positioners can be divided into pneumatic valve positioner, electro pneumatic valve positioner and intelligent valve positioner according to its structure and working principle.
What are the functions of valve positioners?
1. Improve the static characteristics of the control valve and improve the linearity of the valve position.
2. Improve the dynamic characteristics of the control valve and reduce the signal transmission lag of the control valve.
3. Change the flow characteristics of the control valve.
4. Change the response range of control valve to signal pressure to realize split range control.
4. Reverse the valve action.
Why can the valve positioner ensure the correct positioning of the control valve?
The valve positioner can increase the output power of the control valve, reduce the transmission lag of the regulating signal, speed up the moving speed of the valve stem, improve the linearity of the valve, overcome the friction of the valve stem and eliminate the influence of the unbalanced force, so as to ensure the correct positioning of the control valve.
Why should a meter be equipped with a locator under high pressure medium?
When the control valve is used in high-pressure medium, in order to prevent the fluid from leaking from the valve stem packing, the packing is often tightly capped. Therefore, a great friction force is generated in the valve stem, which is caused by the error of the stem stroke. After the positioner is used, it can overcome the effect of these friction forces and the effect of fluid imbalance force, which obviously improves the basic characteristics.
What is the function of positioner under high pressure difference?
When the pressure difference between the two ends of the control valve is greater than 1MPa, the medium will produce a large unbalanced force on the valve core, which will destroy the original working position and cause disturbance to the control system. Especially for the single seat control valve, its unbalanced force is greater than that of the double seat valve. The use of positioner can increase the output pressure, increase the output force of the actuator and overcome the unbalanced effect.
What is the difference between traditional valve positioner and intelligent valve positioner?
The valve opening signal indicated by the traditional valve positioner is actually the signal output from the indicating computer or instrument to the valve positioner, so the actual site position often deviates from the feedback position.
The intelligent valve positioner is equipped with a valve position feedback signal transmitter, which can output the actual action position signal of the valve, and can be fed back to the computer or instrument through the communication protocol. The intelligent valve positioner realizes the digital display and storage of valve position, which provides useful data for predictive maintenance and management of control valve. It also provides an alarm signal to provide fast and correct information for the operator to deal with the accident.
What is the difference of energy saving between traditional valve positioner and intelligent valve positioner?
Traditional valve positioner uses pneumatic amplifier as the controller of secondary loop. In normal operation, the pneumatic amplifier needs a certain amount of air consumption. Two or four piezoelectric valves are used in the intelligent valve positioner. When the input signal of the piezoelectric valve is 1, it is opened and when it is 0, it is closed. Therefore, compressed air is consumed only when the inlet air valve is opened, and no compressed air is consumed under other working conditions (the inlet air pressure electric valve is closed and the exhaust pressure electric valve is opened or closed). Therefore, the intelligent valve positioner has energy-saving performance.
What is the difference between traditional valve positioner and intelligent valve positioner?
In the cascade secondary ring composed of traditional valve positioner, the secondary controller is a pure proportional control law. Therefore, there is a residual difference between the valve position and the set value of the auxiliary ring, which can not guarantee the one-to-one correspondence between the input and output of the auxiliary ring. The control accuracy of traditional valve positioner is generally ± 1%.
The intelligent valve positioner adopts software control algorithm, and the proportional integral function can be used to realize the control without residual error, thus greatly improving the control accuracy. The control accuracy of intelligent valve positioner can reach ± 0.2%.
What are the advantages of intelligent valve positioner?
Through the analysis and comparison of the above theory and engineering application, the intelligent valve positioner can improve the performance of the control system and make the field adjustment more convenient.
1. The method of nonlinear characteristic compensation is extended. The nonlinear characteristics of the controlled object can be compensated by the flow characteristics of the control valve. It can be compensated by ordinary valve positioner or only valve positioner, and can be realized by intelligent digital controller in series with nonlinear link. From the point of view of reducing investment cost and maintenance, the use of intelligent valve positioner or digital controller in series to connect nonlinear compensation link has the advantages of soft connection function, which can easily change the nonlinear characteristics.
2. The type selection of control valve becomes simple. The flow characteristics of control valve can be all star flow characteristics or flow characteristics with convenient processing and high precision, so as to reduce the type of flow characteristics of control valve. If the sleeve and other valve internals are used, the valve body size can be reduced, and the type and specification of spare parts of the control valve can be greatly reduced. The sleeve valve and other control valves can also use balanced valve internals and other components for high pressure difference and noise reduction applications.
3. The valve position detection of valve positioner is non-contact, which can greatly improve the performance of the circuit.