How much do you know about pneumatic butterfly valve

Pneumatic butterfly valve is a control part in the industrial production pipeline. It belongs to the automatic control valve and does not need manual operation. So this kind of valve is usually used in the environment which is not suitable for manual operation. Pneumatic butterfly valve is also widely used in petroleum, chemical, electric power, metallurgy and other industries.

Principle of pneumatic butterfly valve

Pneumatic butterfly valve absorbs dry and lubricated gas through positioner, solenoid valve and other equipment. Then these gases are transmitted to the cylinder body of the pneumatic actuator to form the air source for the operation of the pneumatic actuator. When the air source in the cylinder is get into the air chamber of the pneumatic actuator, the air pressure acts on the piston, then the generated thrust drives the output shaft to rotate, and  drives the valve rod and disc to rotate at the same time, thus completing one opening and closing action of the butterfly valve. Adding a valve positioner to the pneumatic butterfly valve in addition to realized the precise opening adjustment of the butterfly valve. Furthermore, the intelligent positioner can be connected with the field bus to detect the working state of the pneumatic butterfly valve and provide diagnosis.

Maintenance of pneumatic butterfly valve

Maintenance of air cylinder: clean the air cylinder in the pneumatic device of pneumatic butterfly valve, and add oil to the circlip of the cylinder shaft regularly. Open the end cover of the cylinder almost every half a year, and check the cylinder. The inspection items include whether there are sundries, water and grease or not in the cylinder. If there is a lack of lubricating grease, disassemble the cylinder, clean it thoroughly, and then add lubricating grease.

Maintenance of valve body: check the valve body of pneumatic butterfly valve every 6 months. The inspection and maintenance of the valve body include whether the appearance of the valve body is good, whether the flange end connected with the pipeline leaks, whether the sealing performance of the valve sealing surface is good, whether there is wear, whether the butterfly plate rotates flexibly, and whether the valve is stuck with foreign matters. Once any problem is found, it should be repaired and replaced.