Pneumatic Butterfly Valves

What is a pneumatic butterfly valve?

Pneumatic butterfly valve is composed of pneumatic actuator and butterfly valve. Pneumatic butterfly valve is a pneumatic valve that uses the circular butterfly plate rotating with the valve stem as the opening and closing property to realize the opening and closing action. It is mainly used as a block valve. It can also be designed to have the function of regulation or section valve and regulation. Butterfly valve is more and more used in low-pressure large and medium-sized pipelines. Classification of pneumatic butterfly valve: stainless steel pneumatic butterfly valve, hard seal pneumatic butterfly valve, soft seal pneumatic butterfly valve and carbon steel pneumatic butterfly valve. The main advantages of pneumatic butterfly valve are simple structure, small volume, light weight and low cost. The characteristics of pneumatic butterfly valve are particularly remarkable. It is installed in a high-altitude concealed channel, controlled by two position five way solenoid valve, easy to operate and can also adjust the flow medium.

Classification of pneumatic butterfly valves

  1. Pneumatic flange butterfly valve is composed of rubber sealed butterfly valve, carbon steel or stainless steel valve plate and valve stem. It is suitable for regulating flow and intercepting medium on water supply and drainage and gas pipelines with temperature ≤ 80 ~ 120 ℃, such as food, chemical industry, petroleum, electric power, light textile, papermaking, etc.
  2. Pneumatic regulating butterfly valve is a valve (valve plate) rotating around a fixed axis perpendicular to the channel. It is composed of piston double acting or single acting (spring return) pneumatic actuator and butterfly valve. It belongs to rotary high-performance regulating or shut-off valve, equipped with electric, pneumatic valve positioner or solenoid valve, air filter pressure reducer, limit switch (valve position annunciator), It can realize the proportional adjustment and two position cut-off control of the fluid medium in the process pipeline, so as to achieve the automatic control of the flow, pressure, temperature, liquid level and other parameters of the fluid medium.
  3. The pneumatic wafer butterfly valve has a novel structure. The valve body structure is a short-distance wafer structure formed to meet the narrow pipe space. There is no external leakage and the internal leakage meets the national standard.
  4. Pneumatic rubber lined butterfly valve, with flange connection, clamp, sealing lining, nitrile rubber, ethylene propylene rubber, heat-resistant ethylene propylene rubber, natural rubber, neoprene, fluororubber and polytetrafluoroethylene. It has a more reasonable choice according to the chemical properties of the medium.
  5. Pneumatic fluorine lined butterfly valve and anti-corrosion fluorine lined butterfly valve adopt the combination of two-piece valve body, and the valve seat and valve body lining are integrated. When the valve works, only the all plastic valve seat and plastic lined butterfly plate are in contact with the medium, and the product can withstand any medium corrosion except molten alkali metal and elemental fluorine. Among them, d71f46 valve rod and butterfly plate (forging) are integrated, and the surface is evenly coated with a layer of FEP. The valve body has smooth inner surface, small fluid resistance, high CV value, strong circulation capability and moderate torque. It adopts four stage sealing structure and is equipped with the resilient cushion seat of the SI rubber with heat resistance and aging resistance outside the sealing surface, so as to achieve zero leakage of the medium completely.
  6. Pneumatic ventilation butterfly valve, features: there is a fine seam between the valve plate and valve seat. This product is suitable for use in the environment with poor air circulation.

The main features of pneumatic telescopic butterfly valve are as follows: novel and reasonable design, unique structure, light weight, convenient operation and rapid opening and closing; In addition to the function of regulating and intercepting the flow and compensating the thermal expansion and cold contraction caused by the temperature difference of the pipeline, the telescopic butterfly valve can also provide convenience for installation, replacement and maintenance of the valve. The sealing part can be adjusted and replaced, and the sealing performance is reliable.

Working principle of pneumatic butterfly valve

The pneumatic butterfly valve uses the circular butterfly plate rotating with the valve as the opening and closing property to realize the opening and closing action. The pneumatic valve is mainly used as a block valve. It can also be designed to have the function of regulation or section valve and regulation. The butterfly valve is more and more used in low-pressure large and medium-sized pipelines.
Butterfly valve has the advantages of simple structure, small volume and light weight. It is only composed of a few parts. Moreover, it can be opened and closed quickly only by rotating 90 °, and the operation is simple. At the same time, the electric valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is a single resistance when the medium flows through the valve body, so the pressure drop generated through the valve.
Very small, so it has good flow control characteristics. Butterfly valve has two sealing types: elastic seal and metal seal. For the elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.
If the butterfly valve is required to be used as flow control, the main thing is to correctly select the size and type of the valve. The structural principle of butterfly valve is especially suitable for making large-diameter valves. Butterfly valve is not only widely used in petroleum, gas, chemical industry, water treatment and other general industries, but also used in the cooling water system of thermal power station.

Characteristics of pneumatic butterfly valve

  • 1. Small and light, easy disassembly and maintenance, and can be installed at any position.
  • 2. The structure is simple and compact, the operating torque is small, and the 90 ° rotary opening is fast.
  • 3. The flow characteristics tend to be linear and the regulation performance is good.
  • 4. The connection between the butterfly plate and the valve rod adopts a pin free structure, which overcomes the possible internal leakage point.
  • 5. The outer circle of the butterfly plate adopts spherical shape, which improves the sealing performance and prolongs the service life of the valve. There is still zero leakage after opening and closing under pressure for more than 50000 times.
  • 6. The sealing element can be replaced, and the sealing is reliable to achieve two-way sealing.
  • 7. The butterfly plate can be coated according to user requirements, such as nylon or PTFE.
  • 8. The valve can be designed into flange connection and clamp connection.
  • 9. The driving mode can be manual, electric or pneumatic.

Installation requirements of pneumatic butterfly valve

  • 1. Before installation, check whether all parts of the pneumatic butterfly valve are missing and the model is correct. Check whether there are sundries in the valve body and whether there are obstructions in the solenoid valve and silencer.
  • 2. Place the valve and cylinder in the closed state.
  • 3. Install the cylinder on the valve (the installation direction can be parallel or perpendicular to the valve body), and then check whether the screw hole is aligned without too much deviation. If there is a little deviation, turn the cylinder block a little, and then tighten the screws.
  • 4. After installation, the pneumatic butterfly valve shall be commissioned (the air supply pressure is 0.4 ~ 0.6MPa under normal conditions). During commissioning and operation, the solenoid valve shall be opened and closed manually (the manual operation can be effective only after the solenoid valve coil is de energized), and the opening and closing of the pneumatic butterfly valve shall be observed. If it is found that the valve has some difficulty at the beginning of the opening and closing process during the commissioning operation, and then it is normal, it is necessary to reduce the cylinder stroke (adjust the stroke adjusting screws at both ends of the cylinder a little inward at the same time, run the valve to the open position during the adjustment, and then turn off the air source and adjust again) until the valve opening and closing action is smooth and closed without leakage. It should also be noted that the adjustable silencer can adjust the opening and closing speed of the valve, but not too small, otherwise the valve may not act.
  • 5. The hair shall be kept dry before installation and shall not be stored in the open air.
  • 6. Before installing the butterfly valve, check the pipeline to ensure that there are no welding slag and other foreign matters in the pipeline.
  • 7. The manual opening and closing resistance of the butterfly valve body is moderate, and the butterfly valve torque matches the torque of the selected actuator.
  • 8. The flange specification for butterfly valve connection is correct, and the pipe clamp flange is consistent with the butterfly valve flange standard. It is recommended to use special flanges for butterfly valves instead of flat welding flanges.
  • 9. Confirm that the flange is welded correctly. After the butterfly valve is installed, the flange shall not be welded again to avoid scalding the rubber parts.
  • 10. The installed pipe flange shall be aligned and aligned with the placed butterfly valve.
  • 11. Install all flange bolts and tighten them by hand to confirm that the butterfly valve is aligned with the flange, and then carefully open and close the butterfly valve to ensure flexible opening and closing.
  • 12. Fully open the valve, use a wrench to tighten the bolts in diagonal order without washers. Do not tighten the bolts too tightly to prevent serious deformation of the valve ring and excessive opening and closing torque.

Maintenance of pneumatic butterfly valve

  • 1. During the use of pneumatic butterfly valve, it shall be kept clean frequently, and the transmission thread must be lubricated regularly. In case of fault, it shall be stopped immediately, the cause shall be found out and the fault shall be removed.
  • 2. The bolts of the packing gland shall be tightened evenly and shall not be pressed into a skew state, so as to avoid bumping, hindering the movement of the valve stem or causing leakage.
  • 3. During installation, the valve can be directly installed on the pipeline according to the connection mode. Generally, it can be installed at any position of the pipeline, but it shall be convenient for operation and maintenance. Note that the medium flow direction of the stop valve shall be upward under the longitudinal valve disc, and the lifting check valve can only be installed horizontally.
  • 4. When the pneumatic butterfly valve is used, it is only used for full opening or full closing, and it is not allowed to adjust the flow, so as to avoid erosion of the sealing surface and accelerated wear. There is a reverse sealing device in the gate valve and upper thread stop valve. The hand wheel is screwed to the top position to prevent the medium from leaking from the packing.
  • 5. Hand wheel shall be used when opening and closing pneumatic butterfly valve. Do not use lever or other tools to avoid damaging valve parts. Turn the hand wheel clockwise to close, and vice versa to open.
  • 6. Before installation, carefully check whether the pressure and diameter of the valve mark meet the use requirements, eliminate the defects caused by transportation and remove the dirt of the valve parts.
  • 7. The valves stored for a long time shall be inspected regularly. The exposed processing surface shall be kept clean and dirt shall be removed. During storage, both ends of the ball valve shall be blocked and open, and both ends of the pneumatic butterfly valve and channel shall be blocked and closed. They shall be stored neatly in a ventilated and dry place indoors. Stacking or outdoor storage is strictly prohibited.

China pneumatic butterfly valve manufacturer supplies pneumatic butterfly valves for industrial use, in kinds of materials such as carbon steel, stainless steel, alloy steel, etc.

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Pneumatic Butterfly Valve
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