NOVELTY - Linear type outer circulation solar marsh gas digester comprises a gas chamber (3) and a digestion tank (6) integrally arranged. The bottom end of the digestion tank is connected with a dreg discharging pipe (12). The gas chamber is connected with a gas guide pipe, where the digestion tank is connected with a manure pit (2) through a linear unidirectional discharging gate (5). The bottom end of the manure pit penetrates into the center of the digestion tank. The top end of the manure pit is provided with an opening, the lower part of which is provided with an overflowing pipe.    USE - Used as a linear type outer circulation solar marsh gas digester.    ADVANTAGE - The marsh gas digester realizes power-free automatic feeding and automatic agitation through the pressure difference on the outer circulation access with an improved automatic degree of the marsh gas tank.    DETAILED DESCRIPTION - Linear type outer circulation solar marsh gas digester comprises a gas chamber (3) and a digestion tank (6) integrally arranged. The bottom end of the digestion tank is connected with a dreg discharging pipe (12). The gas chamber is connected with a gas guide pipe, where the digestion tank is connected with a manure pit (2) through a linear unidirectional discharging gate (5). The bottom end of the manure pit penetrates into the center of the digestion tank. The top end of the manure pit is provided with an opening, the lower part of which is provided with an overflowing pipe, which is connected with a feeding pipe on the middle lower end of the manure pit through a reflowing pipe to form an outer circulation circuit. One side of the digestion tank is also provided with a precipitating area surrounded by an obstructing plate with an opening. The bottom end of the reflowing pipe penetrates into the precipitating area through a reflowing pipe unidirectional valve.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the linear type outer circulation solar marsh gas digester.    Manure pit (2)    Gas chamber (3)    Linear unidirectional discharging gate (5)    Digestion tank (6)    Dreg discharging pipe (12)