What is the relationship between the opening and flow of pneumatic butterfly valve

Pneumatic butterfly valve is composed of pneumatic actuator and butterfly valve. Pneumatic butterfly valve uses the circular butterfly plate rotating with the valve as the opening and closing property, so as to realize the opening action of pneumatic valve, which is mainly used as block valve, and can also be designed to have the function of regulation or section valve and regulation. At present, butterfly valve is used more and more in low-pressure large and medium diameter pipeline. Pneumatic butterfly valve classification: stainless steel pneumatic butterfly valve, hard seal pneumatic butterfly valve, soft seal pneumatic butterfly valve, carbon steel pneumatic butterfly valve.

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The direction of the air circuit is changed by the electromagnetic reversing valve, and the butterfly valve driven by the actuating cylinder is controlled to open and close. It is used to connect or cut off the air flow in the vacuum pipeline. The medium used is pure air and non corrosive gas. Optional feedback signal device and electric valve positioner. The pneumatic actuator of the pneumatic high true air operated butterfly valve is driven by compressed air. It changes the direction of the air path through the electromagnetic reversing valve, pushes the mechanical movement of the piston rack and gear, and drives the butterfly valve with the angular stroke output torque for the opening and closing movement. In order to connect or cut off the air flow in the vacuum pipeline, it is a new type of pneumatic butterfly valve controlled by pneumatic actuator, which is divided into double acting and single acting (spring return) cylinders. Optional feedback signal device and electric valve positioner.

The relationship between the opening and flow of the pneumatic butterfly valve is basically linear. If it is used to control the flow, its flow characteristics are closely related to the flow resistance of the piping. For example, the caliber and form of the valve installed in the two pipelines are the same, while the flow of the valve will be greatly different if the pipeline loss coefficient is different. If the pneumatic butterfly valve is in the state of large throttling range, the back of the valve plate is prone to cavitation, which may damage the valve. Generally, it is used outside 15 °. When the pneumatic butterfly valve is in the middle opening, the opening shape formed by the valve body and the front end of the butterfly plate takes the valve shaft as the center, and the two sides form different states. The front end of the butterfly plate on one side moves along the flow direction, and the other side moves against the flow direction. Therefore, one side of the valve body and the valve plate form a nozzle like opening, the other side is similar to the orifice like opening, and the flow rate on the nozzle side is much faster than that on the throttle side, while the throttle side is much faster There will be negative pressure under the valve on the flow side, and the rubber seal will often fall off. Analysis of the relationship between opening and flow of the pneumatic butterfly valve.