NOVELTY - A material pressing device comprises a fermentation tank, a hydraulic stirring device and a biogas stirring device. A supporting shaft is arranged at the center of the fermentation tank. A circular material pressing plate is arranged on the supporting shaft under the liquid level of the fermentation tank. Slots are fully distributed on the pressing plate. The four edges of the material pressing plate incline downwards. The hydraulic stirring device comprises a circulating pump arranged outside the fermentation tank.    USE - Material pressing device for biogas fermentation tank.    ADVANTAGE - The device is convenient to operate, and has low power consumption.    DETAILED DESCRIPTION - A material pressing device comprises a fermentation tank, a hydraulic stirring device and a biogas stirring device. A supporting shaft is arranged at the center of the fermentation tank. A circular material pressing plate is arranged on the supporting shaft under the liquid level of the fermentation tank. Slots are fully distributed on the pressing plate. The four edges of the material pressing plate incline downwards. The hydraulic stirring device comprises a circulating pump arranged outside the fermentation tank. The water inlet end of the circulating pump is communicated with the fermentation tank through two water outlet pipes arranged above and under the material pressing plate, respectively, while the water outlet end is communicated with the fermentation tank through more than two water inlet pipes vertical at intervals. The biogas stirring device comprises a biogas output pipe arranged at the top of the fermentation tank. The output end of the biogas output pipe is connected to a biogas collecting device and a biogas compression pump through two pipes, respectively. The output end of the biogas compression pump are communicated with the upper side and the lower side of the liquid level in the fermentation tank through two biogas inlet pipes, respectively.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a material pressing device.