TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The bottom portions of the digestion reaction chamber are further provided with an arc-shaped filling block, which has arched surfaces, and radian of the arc surface formed by the stirring. The flow by anaerobic digester further comprises a safety pressure relief device, and safe pressure relief device comprises a digestion reaction chamber with the methane discharge pipe between the gas discharging device and air pressure safety value of the safety valve. The anaerobic digester further comprises limit anti-explosive device, which is explosion-proof valve digestion reaction chamber on the side wall. The anaerobic digester further comprises an external vacuum system (6), where the vacuum system with a discharging vacuum tank is connected with the discharge tube (12) to receive digested sludge, and a vacuum generator (62) is connected with discharging vacuum tank (61), and the vacuum tank is connected sludge dewatering device (64). The anaerobic digester further comprises sludge reflux device (65), and sludge backflow device, where one end of the sludge dewatering device is connected with the bearing squeeze water, and other end is connected with the digestion reaction chamber to squeeze water into the digestion reaction chamber. The heat insulation device comprises a heating unit and a heat maintaining unit, where the heating unit comprises a heat distributor distributed on the heating coil pipe of the digestion reaction chamber bottom and the four sides, the heat distributor is connected with the heating coil and uniformly distributes the heat source to the heating coil, and the heat insulating device is the digestion reaction layer and an insulating layer composed of heat insulating material. The shape of the stirring paddle is T-shaped, clip shaped, or inversed shaped. The anaerobic digester further comprises monitoring detecting device, where the monitoring detecting device comprises a monitoring device and checking device, the monitoring device comprises a sampling device, temperature monitoring device, flow monitoring device and monitoring device, the detecting device comprises detecting sighting and inspection door, and the checking view mirror is set on the digestion reaction chamber side wall and made of transparent material.