Exhaust device

The utility model discloses an exhaust device which comprises an exhaust elbow and a pneumatic three-way valve, the exhaust elbow comprises a vertical section and a horizontal section, the bottom of the vertical section is provided with an exhaust air inlet, the left end of the horizontal section is connected with the vertical section, the right end of the horizontal section is connected with an inlet of the pneumatic three-way valve, and a first outlet of the pneumatic three-way valve is connected with a dust collector; a second outlet of the pneumatic three-way valve faces downwards and is connected with a vertical pipe, the bottom end of the vertical pipe is hermetically connected with an exhaust hood, the exhaust hood is in a closed barrel shape, and an exhaust port is formed in the bottom of the exhaust hood; a filter bag support frame is fixed at the upper end in the vertical pipe, the filter bag support frame is in a hollow barrel shape directly communicated to the middle part or the lower part of the