What is a pneumatic butterfly valve?
Pneumatic regulating butterfly valve is a valve (valve plate) that rotates around a fixed axis perpendicular to the channel. It is composed of a piston double-acting or single-acting (spring return type) pneumatic actuator and a butterfly valve. It is a rotating high-performance regulating valve. Or cut-off valves, equipped with electricity, pneumatic valve positioner or solenoid valve, air filter pressure reducer, limit switch (valve position return device), which can realize the proportional adjustment and two-position cut-off of the fluid medium in the process pipeline Control, thereby achieving automatic control of the flow, pressure, temperature, liquid level and other parameters of the fluid medium.
The pneumatic wafer-type butterfly valve has a novel structure. The valve body is constructed as a short-distance wafer structure to meet the narrow pipeline space. It has zero external leakage and internal leakage in line with national standards.
Pneumatic rubber-lined butterfly valve, the connection method is flange, clamping, the sealing lining is nitrile rubber, ethylene propylene rubber, heat-resistant ethylene propylene rubber, natural rubber, neoprene rubber, fluorine rubber, polytetrafluoroethylene, according to the medium chemistry Properties have more reasonable options.
Pneumatic fluorine-lined butterfly valve, anti-corrosion fluorine-lined butterfly valve adopts a two-piece valve body combination. The valve seat and valve body lining are integrated. When the valve is working, only the full plastic valve seat and plastic-lined butterfly plate are in contact with the medium. The product can withstand Corrosion by any medium “except molten alkali metals and elemental fluorine”, in which the D71F46 valve stem and butterfly plate (forged) are integrated, and the surface is evenly coated with a layer of FEP.
The inner surface of the valve body channel is smooth, the fluid resistance is small, the CV value is high, the flow capacity is strong, and the torque is moderate. It adopts a four-level sealing structure and is equipped with an elastic liner valve seat of temperature-resistant and anti-aging SI rubber outside the sealing surface, fully achieving Zero leakage of media.
Pneumatic ventilation butterfly valve features a thin gap between the valve plate and valve seat. This product is suitable for use in environments with poor air circulation.
The main features of the pneumatic telescopic butterfly valve are as follows: novel and reasonable design, unique structure, light weight, easy operation, rapid opening and closing; in addition to regulating and shutting off, and compensating for thermal expansion and contraction caused by the temperature difference in the pipeline, the telescopic butterfly valve also It can provide convenience for installation, replacement and maintenance of valves. The sealing parts are adjustable and replaceable, and the sealing performance is reliable.
Butterfly valve characteristics:
1. Small and lightweight, easy to disassemble and repair, and can be installed at any location.
2. The structure is simple and compact, the operating torque is small, and the 90° rotation opens quickly.
3. The flow characteristics tend to be linear and the adjustment performance is good.
4. The connection between the butterfly plate and the valve stem adopts a pinless structure, which overcomes possible internal leakage points.
5. The outer circle of the butterfly plate adopts a spherical shape, which improves the sealing performance and extends the service life of the valve. It can maintain zero leakage after opening and closing under pressure for more than 50,000 times.
6. The seals are replaceable and the sealing is reliable and bi-directional.
7. The butterfly plate can be spray-coated according to user requirements, such as nylon or polytetrafluoroethylene.
8. The valve can be designed with flange connection and wafer connection.
9. The driving mode can be manual, electric or pneumatic.
1. Pneumatic butterfly valve has gear-type double pistons, large output torque and small size.
2. The cylinder is made of aluminum gold, which is light in weight and beautiful in appearance.
3. Manual operating mechanisms can be installed on the top and bottom.
4. The rack-type connection can adjust the opening angle and rated flow rate.
5. The butterfly valve actuator can be equipped with electrified signal feedback indication and various accessories to achieve automated operation.
6. IS05211 standard connection provides convenience for product installation and replacement.
7. The adjustable joint screws at both ends allow the standard product to have an adjustable range of ±4° between 0° and 90°. Ensure synchronization accuracy with the valve.
Butterfly valve installation requirements:
1. Before installation, check that all parts of the pneumatic butterfly valve are not missing, that the model is correct, that there are no debris in the valve body, and that there are no obstructions in the solenoid valve and silencer.
2. Place both valve and cylinder in closed position.
3. Install the cylinder onto the valve (the installation direction can be parallel or perpendicular to the valve body), and then check whether the screw holes are aligned. There will not be much deviation. If there is a slight deviation, just rotate the cylinder body a little. , and then tighten the screws.
4. After the installation is completed, debug the pneumatic butterfly valve (under normal circumstances, the air supply pressure is 0.4~0.6MPa). During debugging and operation, the solenoid valve must be opened and closed manually (manual operation can only be effective after the solenoid valve coil is de-energized).
Observe the opening and closing of the pneumatic butterfly valve. If during the debugging operation it is found that the valve has some difficulty in the initial opening and closing process, but then normalizes, the cylinder stroke needs to be adjusted smaller (turn the stroke adjustment screws at both ends of the cylinder a little inward at the same time, and the valve needs to be moved to the open position during adjustment) , then turn off the air source and adjust again) until the valve opens and closes smoothly and closes without leakage. It should also be noted that the adjustable muffler can adjust the opening and closing speed of the valve, but it cannot be adjusted too small, otherwise the valve may not operate.
5. Defa should be kept dry before installation and should not be stored in the open air.
6. Before installing the butterfly valve, check the pipeline to ensure that there is no foreign matter such as welding slag in the pipeline.
7. The manual opening and closing resistance of the butterfly valve body is moderate, and the butterfly valve torque matches the selected actuator torque.
8. The specifications of the flange used for connecting the butterfly valve are correct, and the pipe clamp flange is consistent with the standard of the butterfly valve flange. It is recommended to use special flanges for butterfly valves, and flat welding flanges are not allowed.
9. Confirm that the flange is welded correctly. Do not weld the flange after the butterfly valve is installed to avoid burning the rubber parts.
10. The installed pipe flange must be aligned and aligned with the inserted butterfly valve.
11. Install all flange bolts and tighten them by hand. Make sure that the butterfly valve and flange are aligned, and then carefully open and close the butterfly valve to ensure flexible opening and closing.
12. Fully open the valve and use a wrench to tighten the bolts in diagonal order without washers. Do not overtighten the bolts to prevent severe deformation of the valve ring and excessive opening and closing torque.
Maintenance of pneumatic butterfly valve:
1. During use, the pneumatic butterfly valve should always be kept clean, and the transmission thread must be regularly lubricated. When a fault is found, it should be stopped immediately, and the cause should be identified and the fault eliminated.
2. The bolts of the packing gland should be tightened evenly and should not be pressed into a crooked state to avoid damage, hinder the movement of the valve stem or cause leakage.
3. During installation, the valve can be installed directly on the pipeline according to the connection method. Under normal circumstances, it can be installed at any position in the pipeline, but it needs to be easy to operate and maintain. Note that the flow direction of the medium in the stop valve should be upward from the bottom of the longitudinal valve disc. The lift check valve can only be installed horizontally.
4. When the pneumatic butterfly valve is used, it can only be fully opened or fully closed. It is not allowed to adjust the flow rate to avoid erosion of the sealing surface and accelerated wear. There is an inverted sealing device in the gate valve and the upper thread stop valve. Turn the handwheel to the uppermost position and tighten it to prevent the medium from leaking from the packing.
5. Use the handwheel when opening and closing the pneumatic butterfly valve. Do not use levers or other tools to avoid damaging the valve parts. Turn the handwheel clockwise to turn off, and vice versa to turn on.
6. Before installation, you must carefully check whether the pressure and diameter marked on this valve meet the usage requirements, eliminate defects caused by the transportation process, and eliminate dirt on the valve parts.
7. Valves stored for a long time should be inspected regularly. The exposed processing surface must be kept clean and dirt removed. During storage, the ball valve should be blocked at both ends and in an open state. For pneumatic butterfly valves, both ends of the channel should be blocked and in a closed state. Store neatly in a ventilated and dry place indoors. Stacking or open storage is strictly prohibited.
The composition and classification of positioners in pneumatic butterfly valves:
The valve positioner is the main accessory of the pneumatic butterfly valve and is used in conjunction with the pneumatic butterfly valve. The valve positioner is a regulator that functions as a proportional amplifier. The valve positioner and regulating valve form a valve stroke adjustment system. The main components of this system are a gas volume element and a hysteresis element.
Valve positioners can be divided into pneumatic valve positioners, electrical valve positioners and intelligent valve positioners according to their structural forms and working principles.
Its function:
1. Eliminate lag;
2. Eliminate incongruity;
3. Used in composite adjustment systems;
4. Realize reverse action;
