Biogas fermentation deslagging device and biogas fermentation tank

The invention discloses a biogas fermentation deslagging device, comprising a conveying auger arranged in a manner of gradually inclining upwards from the front end to the rear end, wherein an external cylinder body sleeves the outside of the cylinder body of the conveying auger; the cylinder body is provided with filter holes; the external cylinder body is provided with a slurry outlet; the front end of the cylinder body is provided with an opening; the rear end of the cylinder body is provided with a discharging chute; an extending cylinder is connected with the front-end cylinder opening of the cylinder body; the front-end cylinder opening of the extending cylinder is provided with a horn opening; the spiral shaft of the conveying auger extends forward to the front end of the extending cylinder; an impeller sleeves the end part of the extending section of the extending cylinder; the inner wall of the extending cylinder between the impeller and the conveying auger is circumferentially provided with an axially-extending flow guiding plate; the conveying auger is divided into a spiral pre-extruding section and a spiral extruding section from front to rear; the spiral shaft in the spiral extruding section is a conical shaft; the large diameter end of the spiral extruding section is close to the tail end of the conveying auger. According to the biogas fermentation deslagging device, the problems of difficulty in discharging, reduction of biogas yield and high maintenance cost caused by scums and incrustation in a large-medium mixed raw material fermentation biogas engineering fermentation tank are completely solved.