Device for automatically replacing filter cotton by sensing gas flow velocity

The invention relates to the related field of waste gas purification equipment, and discloses a device for automatically replacing filter cotton by sensing gas flow velocity. The device comprises a main body box, a fiber filter screen cavity is arranged in the main body box, the upper side of the fiber filter screen cavity is communicated with a clamping cavity, and the front side of the fiber filter screen cavity is communicated with a gas flow cavity with a forward opening; the left side of the fiber filter screen cavity communicates with a new filter screen storage cavity communicating withthe clamping cavity, the right side of the fiber filter screen cavity communicates with an old screen storage cavity, and the left side of the new filter screen storage cavity communicates with a rack moving cavity. The device starts to sense the gas permeability of the fiber filter cotton by sensing the gas passing rate in the gas suction process; the fiber filter cotton is automatically replaced after being triggered,