The Working Principle And Maintenance And Debugging Method Of Pneumatic Butterfly Valve

The pneumatic butterfly valve is composed of a pneumatic actuator and a butterfly valve. The pneumatic butterfly valve uses a circular butterfly plate that rotates with the valve stem for opening and closing, so as to realize the activation action. The pneumatic valve is mainly used as a shut-off valve, and can also be designed to have the function of adjustment or section valve and adjustment. At present, the butterfly valve is used in low pressure and large It is used more and more on medium-bore pipes.

The working principle of pneumatic butterfly valve

The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0°-90°. When the rotation reaches 90°, the valve is in a fully open state. The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. Moreover, it can be quickly opened and closed by only rotating 90°, and the operation is simple. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics. Butterfly valves have two sealing types: elastic seal and metal seal. For elastic sealing valves, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate.

Pneumatic butterfly valve maintenance and debugging

1. Cylinder inspection and maintenance plan

Usually do a good job of cleaning the surface of the cylinder and oiling the circlip of the cylinder shaft. Open the end cover of the cylinder regularly every 6 months to check whether there are sundries and moisture in the cylinder, and the state of grease. If the lubricating grease is lacking or has dried up, it is necessary to disassemble the cylinder for comprehensive maintenance and cleaning before adding lubricating grease.

2. Valve body inspection

Every 6 months, check whether the appearance of the valve body is good, whether there is leakage on the mounting flange, if it is convenient, check whether the seal of the valve body is good, no wear, whether the valve plate is flexible, and whether there is any foreign matter stuck in the valve.

Cylinder block disassembly and assembly methods and precautions:

First remove the cylinder from the valve body, first remove the cover at both ends of the cylinder, pay attention to the direction of the piston rack when removing the piston, then use external force to rotate the cylinder shaft clockwise to make the piston run to the outermost side, and then close the valve The hole is ventilated slowly and the piston is pushed out gently with air pressure, but this method must pay attention to ventilate slowly, otherwise the piston will suddenly eject, which is a bit dangerous! Then remove the circlip on the cylinder shaft, and the cylinder shaft can be opened from the other end. take it out. Then you can clean each part and add grease. The parts that need to be greased are: the inner wall of the cylinder and the piston seal ring, the rack and the back ring, as well as the gear shaft and the seal ring. After lubricating the grease, it must be installed according to the order of dismantling and the reverse order of the parts. After that, it must be installed according to the order of dismantling and the reverse order of the parts. Pay attention to the position of the gear and rack, and ensure that the piston shrinks to the position when the valve is open. The groove on the upper end of the gear shaft is parallel to the cylinder block during the innermost position, and the groove on the upper end of the gear shaft is perpendicular to the cylinder block when the piston is stretched to the outermost position when the valve is closed.

Cylinder and valve body installation and debugging methods and precautions:

First put the valve in the closed state by external force, that is, turn the valve shaft clockwise until the valve plate is in sealing contact with the valve seat, and at the same time put the cylinder in the closed state (that is, the small valve above the cylinder shaft The groove is perpendicular to the cylinder body (for a valve that rotates clockwise to close the valve), then install the cylinder to the valve (the installation direction can be parallel to or perpendicular to the valve body), and then check whether the screw holes are aligned. Large deviation, if there is a little deviation, just turn the cylinder block a little, and then tighten the screws. Pneumatic butterfly valve debugging first check whether the valve accessories are installed completely, solenoid valve and muffler, etc., if not complete, do not debug, the normal supply air pressure is 0.6MPA±0.05MPA, before operation, make sure that there is no debris stuck in the valve plate in the valve body At the first commissioning and operation, use the manual operation button of the solenoid valve (the solenoid valve coil is powered off during manual operation, and manual operation is valid; when the electric control operation is performed, the manual twist is set to 0 and the coil is powered off, and manual operation is valid; 0 position 1 is to close the valve, 1 is to open the valve, that is, the valve is opened when the power is turned on, and the valve is closed when the power is off. state.

If it is found that the pneumatic butterfly valve manufacturer is very slow at the initial position of the valve opening during the commissioning and operation, but it is very fast as soon as it moves. Quick, in this case, the valve is closed too tightly, just adjust the stroke of the cylinder a little bit (adjust the stroke adjustment screws at both ends of the cylinder a little at the same time, when adjusting, the valve should be moved to the open position, and then the air source should be turned off Turn it off and then adjust), adjust until the valve is easy to open and close in place without leaking. If the muffler is adjustable, the switching speed of the valve can be adjusted. It is necessary to adjust the muffler to the appropriate opening of the valve switching speed. If the adjustment is too small, the valve may not operate.

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