Working Principle, Maintenance And Debugging Of Pneumatic Butterfly Valve
Sanitary Butterfly Valve Working principle and maintenance and debugging
Pneumatic butterfly valve is composed of pneumatic actuator and butterfly valve. Pneumatic butterfly valve is a pneumatic valve that uses a circular butterfly plate that rotates with the valve to open and close to realize the activation action. It is mainly used as a shut-off valve. It can also be designed to have the function of regulation or segment valve and regulation. At present, butterfly valves are increasingly used in low-pressure large and medium-caliber pipelines.
1. 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 it rotates to 90°, the valve is in a fully open state. The butterfly valve has a simple structure, small size, light weight, and is composed of only a few parts. Moreover, it can be quickly opened and closed by rotating 90°, which is simple to operate. At the same time, the valve has good fluid control characteristics. When the butterfly valve is in the most open position, the thickness of the butterfly plate is the most resistance when the medium flows through the valve body. Therefore, the pressure drop generated by the valve is very small, so it has good flow control characteristics. Butterfly valves have two types of sealing: elastic sealing and metal sealing. For elastic sealing valves, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.
2 Maintenance and debugging of pneumatic butterfly valves
2.1 Inspection and maintenance of solenoid valves and mufflers
Inspect and maintain the solenoid valve every 6 months, mainly to check whether there is dirt blocking the solenoid valve, whether the valve core moves freely, whether the muffler is blocked by dirt, and whether it is unobstructed. Whether the air source is clean and free of moisture.
2.2 Cylinder inspection and maintenance plan
Usually clean the cylinder surface and refuel the cylinder shaft retaining ring. Open the cylinder end cover regularly every 6 months to check whether there is debris and moisture in the cylinder, as well as the grease status. If the grease is lacking or has dried, the cylinder needs to be disassembled for comprehensive maintenance and cleaning before adding grease.
2.3 Valve body inspection
Every 6 months, check whether the valve body appearance is good, whether the mounting flange is leaking, and if it is convenient, check whether the valve body seal is good and free of wear, whether the valve plate is flexible, and whether the valve is stuck with foreign objects.
2.4 Cylinder body disassembly and assembly methods and precautions
First remove the cylinder from the valve body, first remove the two ends of the cylinder cover, when removing the piston, be sure to pay attention to the direction of the piston rack, then use external force to rotate the cylinder shaft clockwise to make the piston run to the outside, then slowly ventilate the valve hole and use air pressure to gently push the piston out, but this method must pay attention to slowly ventilate, otherwise the piston will suddenly spray out, which is a bit dangerous! Then remove the retaining ring on the cylinder shaft, and the cylinder shaft can be taken out from the other end. Then you can clean each component 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, and the gear shaft and the seal ring. After adding grease, you must install it in the reverse order of the order and parts of the disassembly. Be sure to pay attention to the position of the gear rack, and make sure that when the valve is in the open position, that is, when the piston is retracted to the inside, the upper end groove of the gear shaft is parallel to the cylinder body, and when the valve is in the closed position, that is, when the piston is extended to the outside, the upper end groove of the gear shaft is perpendicular to the cylinder body.
2.5 Installation and debugging methods and precautions of cylinder and valve body
First, put the valve in the closed state with external force, that is, rotate the valve shaft clockwise until the valve plate and the valve seat are in sealing contact, and at the same time put the cylinder in the closed state (that is, the small groove above the cylinder shaft is perpendicular to the cylinder body for the valve that rotates clockwise to close the valve), then install the cylinder on 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 too much deviation. If there is a slight deviation, just turn the cylinder body a little, and then tighten the screws. When debugging a pneumatic butterfly valve, first check whether the valve accessories are fully installed, such as the solenoid valve and muffler. If they are incomplete, debugging is not allowed. The normal air supply pressure is 0.6MPA±0.05MPA. Before operation, ensure that there is no debris stuck in the valve plate in the valve body. During debugging and operation, manually operate the manual button of the solenoid valve (the solenoid valve coil loses power during manual operation, and manual operation is effective; when operating electronically, put the manual knob in the 0 position and lose power, and manual operation is effective; 0 position is to close the valve, and 1 position is to open the valve, that is, open the valve with electricity and close the valve without electricity. If you need to close the valve with electricity, the open position without electricity is to close the valve. Rotate the solenoid valve coil 180 degrees and install it), and observe the valve operation status. If during the commissioning process, it is found that the valve is very slow at the initial opening position, but it is very fast once it is actuated, in this case, the valve is closed too tightly, and you only need to adjust the cylinder stroke a little smaller (adjust the stroke adjustment screws at both ends of the cylinder a little inward at the same time, and when adjusting, you need to run the valve to the open position, and then turn off the air source and adjust it again), adjust it until the valve opens easily and closes in place without leaking. If the silencer is adjustable, the valve opening and closing speed can be adjusted. The silencer needs to be adjusted to the appropriate opening and closing speed of the valve. If it is adjusted too small, the valve may not actuate.
