How to equip a regulating intake valve on a centrifugal fan? The regulating door is a device used to adjust the total flow size of a centrifugal fan. The regulating door leaf is flower shaped and radially installed in front of the air inlet. Due to the use of external transmission structure, rotation is convenient and easy. The adjustment range ranges from 90 ° (fully closed) to 0 ° (fully open). When viewed from the direction of the air intake, rotating the centrifugal fan plate handle to the right from bottom to top often results in a fully closed to fully open position; Rotate the centrifugal fan to the left and turn the handle from fully closed to fully open from top to bottom. In order to ensure the normal operation of the regulating valve, it is necessary to use high-temperature (260 ℃) bentonite grease as the lubricating grease, so that the centrifugal fan can still ensure the lubrication effect during high-temperature operation.