Cermaic Tile Film,Pe Protective Film For Tile,Anti-Dirt Pe Protective Film,Peel Ceramic Tile Pe Protective Film Wuxi Xinhao Protective Film CO.,Ltd , https://www.cotton-balewrap.com
Control valve composition
Control valve by the implementing agencies and regulatory agencies. Actuators can be broken down into two parts: force or torque conversion components and displacement conversion components. The part that converts the controller output signal to the thrust or torque of the control valve is called a force or torque conversion part; the part that converts a force or torque into a linear or angular displacement is called a displacement conversion part. The adjustment mechanism converts the displacement signal into a change in the flow area between the valve plug and the seat, changing the value of the manipulated variable. There are different types of implementing agencies. According to the energy used, the implementing agency is divided into pneumatic, electric and hydraulic three categories. Pneumatic actuators with a long history, low prices, simple structure, stable performance, easy maintenance and intrinsic safety features, therefore, the most widely used. Electric actuators can be directly connected to electric instruments or computers, do not need the characteristics of electrical conversion links, but the price is expensive, complex structure, the application needs to be considered explosion-proof and other issues. Hydraulic actuator has the thrust (or thrust moment) the advantages of large, but the volume of the device, the flow path is complex. Typically, the use of electro-hydraulic combination of methods used to require large thrust (torque) applications. According to the moving direction output by the actuator, the actuator is divided into positive and negative actuator. Positive actuator When the input signal increases, the stem moves outward. The reaction actuator moves inward as the input signal increases. According to the type of displacement output by the actuator, the actuator is divided into a linear actuator, an angular actuator and a multi-actuator. Straight travel actuator output linear displacement. Angular travel actuator output angular displacement, angular displacement of less than 360 °, for example, the rotation angle of 90 ° or 60 ° butterfly valve actuator. Multi-turn actuators and rotary actuators are similar, but the rotation of the angular displacement can be multi-turn. According to the type of actuator components, pneumatic actuator is divided into thin film actuator, piston actuator, gear actuator, manual actuator, electro-hydraulic actuator. By actuator action, the implementing agencies are divided into continuous, discrete two categories. The output of continuous type actuators is a continuously varying displacement signal. The output of the discrete actuator type is the change of displacement signal. Solenoid valve The most commonly used electric discrete control valve, safety vent valve is also a common discrete control valve. According to the installation of implementing agencies, the implementing agencies are divided into direct-mounted, side-mounted. Direct-mounted actuator installed directly on the regulatory agencies. Side mounted actuator mounted on the side of the adjustment mechanism, which through a force device to change the direction of displacement and force size. Actuator output and input by the action characteristics, the implementing agencies are divided into proportional, proportional integral type. The output of the proportional actuator has a linear relationship with the input signal. The output of the proportional-integral actuator is the sum of the proportional and integral effects of the input signal. According to the type of actuator input signal, the implementing agency is divided into analogue implementing agencies and digital implementing agencies. Analog actuators receive analog signals, for example, 20 ~ 100kPa pressure signal, 4 ~ 20mA standard current signal. The digital actuator receives the digital signal, usually a series of binary signals, used to open and close the corresponding digital valve. With the application of field bus technology, the implementing agencies receiving fieldbus digital signals are being widely used. There are different types of adjustment mechanisms. Normally, the adjustment mechanism is called a valve. According to the classification of the structure, the adjusting mechanism is divided into straight-through single seat valve, direct seat valve, three-way valve, angle valve, high pressure valve, diaphragm valve sleeve valve, eccentric ball valve rotation valve, butterfly valve and so on. Most common valves add relevant valve accessories such as actuators, positioners, and valve position detection sensors. According to the flow characteristics, regulating agencies are divided into linear valves, such as the percentage valve and quick opening valve. According to the form of the spool, the regulating mechanism is divided into the straight stroke and the angular stroke spool. Straight stroke valve spool, sub-plate type, plunger type, window type, multi-level and sleeve type. Angle stroke valve spool is divided into eccentric rotation, ball, V-cut and butterfly and so on. Press the regulating valve body in the form of regulation agencies are divided into ordinary type, heat or heat-absorbing, bellows sealed, long-necked and so on. Among them, the cooling adjustment mechanism for high temperature; endothermic adjustment mechanism for low temperature; for deep freezing applications, the use of long neck adjustment mechanism; bellows sealed type for toxic, volatile or expensive fluid medium control , To prevent media leakage loss and casualties. According to the different flow, the regulatory agencies are divided into flow and flow off, the center outward and outward to the center. In a flowopen-type regulator, the flow direction of the fluid at the spool throttle coincides with the direction in which the valve is opened. In a flowclose-type regulating mechanism, the flow direction of the fluid at the throttle of the spool coincides with the direction in which the valve is closed. In an out-ward-like adjustment mechanism, fluid flows outwardly from the center of the sleeve. External to the inward type of adjustment mechanism, the fluid flow from the outside of the sleeve to the center. According to the movement of the valve stem changes in the area of ​​circulation is different, the regulating body is divided into the body valve and anti-body valve. When the stem of the positive valve is moved to the valve body, the flow area is reduced and the flow rate is reduced. When the stem of the anti-body valve moves to the valve body, the circulation area increases and the flow rate increases. According to different spool-oriented approach, the regulatory agencies are divided into top-oriented, top and bottom-oriented, stem-oriented, seat-oriented and cage-oriented. The valve guide of the top guide adjusting mechanism is guided by an upper valve cover or a guide shaft inside the valve body; the valve core of the top and bottom guide adjusting mechanism is simultaneously oriented by the guide shafts of the upper and lower valve caps; the valve rod guide is a guide shaft And the valve seat ring center, the sleeve to guide the stem; valve seat guide in the small flow control valve, which is guided through the valve seat; cage guide adjustment structure of the valve spool and cage composition of the sleeve structure, Throughout the travel range, the spool contacts the inner surface of the cage with a cage hole in the cage, which changes the flow area of ​​the cage when it moves. Cage and bonnet, valve seat is self-aligning, in order to achieve the spool guide. According to whether the valve body is separated, the adjustment mechanism is divided into the whole valve and the valve body separation valve. Integral valve body is a whole; valve body valve can be separated, easy to disassemble and internal cleaning, internal lining replacement. According to the body of the material, the regulatory agencies are divided into cast iron valves, cast steel valves, brass valves, stainless steel valves, hot plastic valves, titanium valves. In addition, according to the valve application, there are some special valves, such as low noise valve, diaphragm valve, anti-cavitation valve, anti-corrosion valve, steam control valve, pressure reducing valve and so on. In addition to the actuator and the adjustment mechanism, the control valve can be added with accessories to control the action of the valve, including the valve positioner, handwheel mechanism, signal converter, valve position detection, transmission and self-locking devices, Control valve functions more perfect, the use of more convenient, more flexible applications, superior performance.