Octagonal septic tank mold is a kind of forming tool of cement septic tank. The combined square reinforced concrete septic tank has only one tank type structure. The through port is used instead of the water outlet and the air vent. It is easy to standardize the production and installation. The production and installation is simple and convenient. The cement consumption is greatly reduced, the floor area is small, the volume of sewage is large, the contact surface between the tank walls is large, the pressure is good, and the manufacturing cost is low. The mould of the septic tank is mainly composed of the pipe tank. The tank type of the pipe tank is square with cut corners. Several pipe tanks are connected up and down to form a unit septic tank. Several unit septic tanks are connected in series or in parallel on the same plane to form a combined square reinforced concrete septic tank, which is located in the combined square reinforcement. The upper end pipe wall of the first unit septic tank of the concrete septic tank is provided with a through port between the pipe tank wall adjacent to the water inlet and each unit septic tank wall adjacent to the water inlet, and the upper end pipe tank wall of the last unit septic tank is provided with a water outlet, the water inlet is higher than the through port, and the water outlet is flush with or lower than the through port. The upper end of each unit septic tank is provided with a b\uckle cover, and the uckle cover is provided with a covered wellhead. The lower end of each unit septic tank is provided with a bottom plate or a cement compression plane. The water inlet and water outlet are both located on the wall of the upper end pipe pool. The pipe pool is made of reinforced concrete.
The overall structure of the octagonal septic tank mold is composed of multiple single septic tanks. Each single septic tank includes a tank base and a tank body. The top of the tank body is provided with a cover plate, which is provided with a tank cover. The tank wall of the tank body is provided with a water inlet hole, a water outlet hole and a vent hole. The tank base of each single septic tank, the outer wall and the inner wall of the tank body are mostly polygonal. The joint between the upper opening of the tank base and the lower opening of each single septic tank is sealed by rubber sealing strip; the water outlet of the first single septic tank and the water inlet of the second single septic tank are connected and sealed by rubber pipe or high-density polyethylene bellows. The wall and bottom of each single septic tank are an integral structure; the outer wall and inner wall of each single septic tank are circular or rectangular; the outer wall and inner wall of each single septic tank are polygonal and evenly distributed.