Standard installation and maintenance of pneumatic butterfly valves to increase production efficiency and quality
The pneumatic butterfly valve is composed of a pneumatic actuator and a butterfly valve, and is opened and closed by a circular disc rotating with the valve stem to realize a pneumatic valve that is activated. At present, butterfly valves are used more and more on low pressure large diameter pipes.
With the rapid development of the pharmaceutical industry, the use rate of pneumatic butterfly valves is also gradually increasing. In terms of advantages, the pneumatic butterfly valve is quick and easy to open and close, and has low fluid resistance; the structure is simple, the volume is small, the weight is light; the mud can be transported, and the liquid is accumulated in the pipeline port; under the low pressure, the excellent sealing can be completed; Good performance.
There are advantages and disadvantages. The sealing performance of pneumatic butterfly valve is relatively poor compared with pneumatic ball valve and pneumatic valve. Due to the structure of pneumatic butterfly valve and the limitation of sealing material, it is not suitable for high temperature and high pressure pipeline system. The general working temperature is below 300 °C, below PN40; pneumatic The flow adjustment range of the butterfly valve is not large. When the opening is 30%, the flow rate reaches nearly 95%. The pneumatic butterfly valve and the pneumatic ball valve are also not allowed to adopt the valve with the diameter contraction under certain working conditions.
For the installation of pneumatic butterfly valve, the insiders said, first, before installation, check whether there are any missing parts of the pneumatic butterfly valve, the model is correct, check the valve body for no debris, no obstruction in the solenoid valve and silencer.
Second, put the valve and cylinder in the closed state; third, install the cylinder to the valve (the installation direction is parallel or perpendicular to the valve body), and then see if the screw hole is aligned, there will be no deviation, such as With a slight deviation, turn the cylinder block and tighten the screws.
After the installation is completed, the pneumatic butterfly valve is debugged (normally, the air supply pressure is 0.4~0.6MPa), and the solenoid valve must be manually opened and closed during commissioning operation (manual operation can be effective after the solenoid valve coil is de-energized), observe the pneumatic The opening and closing of the butterfly valve.
If during the commissioning operation, it is found that the valve is a little difficult at the beginning of the opening and closing process, and then normal, the cylinder stroke needs to be adjusted down (the stroke adjustment screw at both ends of the cylinder is adjusted at the same time, and the valve needs to be moved to the open position when adjusting. Then turn off the air supply and adjust) until the valve opening and closing action is smooth and closed without leakage.
"Install the butterfly valve money to check the pipeline, to ensure that there is no foreign matter such as welding slag in the pipeline, the butterfly valve body manual opening and closing resistance should be moderate, the butterfly valve torque should match the selected actuator torque." The manufacturer said, to confirm the flange welding is correct, the butterfly valve Do not weld the flange after installation to avoid scalding the rubber parts.
Then, how to maintain the pneumatic butterfly valve? I understand that the pneumatic butterfly valve should always be kept clean during use. The transmission thread must be lubricated. When the fault is found, stop using it immediately, and find out the cause and then clear the fault.
The bolts of the packing gland should be evenly tightened and should not be crushed to prevent the bump from moving or causing leakage. In addition, when using a pneumatic butterfly valve, it is only fully open or fully closed, and it is not allowed to adjust the flow rate to avoid erosion of the sealing surface and accelerate wear. The gate valve and the upper thread stop valve have an inverted sealing device, and the hand wheel is screwed to the upper position to tighten, thereby preventing the medium from leaking from the packing.
Use the handwheel when opening and closing the pneumatic butterfly valve. Do not use levers or other tools to avoid damage to the valve. It should be reminded that the valves stored for a long time should be inspected regularly, and the exposed surface must be kept clean and dirt removed.
When storing, the ball valve should be blocked at both ends and open. Pneumatic butterfly valve, both ends of the channel should be blocked and closed, neatly stored in a ventilated and dry place indoors, no stacking or open storage.
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