NOVELTY - A sealing-free segmental cover-uncovering type straw marsh gas pool comprises fermenting tank (1), water pressure tank (11), feeding port (2) and discharge hole (21). Tank body of the marsh gas tank has rectangular opening, where upper part is above ground by 500 mm, and lower part is embedded underground. Cross section of the tank is convex. Two small transverse lines at convex middle part are ring beams (12), where upper part is water-pressure tank, and lower part is a fermenting tank whose left and right sides of bottom is provided with large circular angle.    USE - Sealing-free segmental cover-uncovering type straw marsh gas pool.    ADVANTAGE - The pool prevents crust of straw with grids , realizes exhaust of straw biogas residue with big feeding and discharging cover, and has a service life for a hundred years. It can fully use straw gas to produce marsh gas, which is good for providing farmers with 3hundred million of marsh gas tanks for free, realizes supplying heat energy, giving light and saving energy and reducing emission. The pool also controls environment, produces fertilizer, and ensures improvement in 8 hundred million mu of fertile lands, thus realizing environmental improvement of the energy conservation and emission reduction for people.    DETAILED DESCRIPTION - A sealing-free segmental cover-uncovering type straw marsh gas pool comprises fermenting tank (1), water pressure tank (11), feeding port (2) and discharge hole (21). Tank body of the marsh gas tank has rectangular opening, where upper part is above ground by 500 mm, and lower part is embedded underground. Cross section of the tank is convex. Two small transverse lines at convex middle part are ring beams (12), where upper part is water-pressure tank, and lower part is a fermenting tank whose left and right sides of bottom is provided with large circular angle. Ring beams are two long side beam pool extending for 12 cm to form two convexes. Each convex side is provided with 2 openings and 6 rope holes. The convex (50 mm from the retaining wall from left in turn) is provided with large grid and small grid. Small tank is downwards pressed on corresponding size of the grid. Feeding plate extends into feeding port which can ferment pool of pool bottom, and agitating oar in and out and stirring. Top part of two storage tanks are respectively through pipe in turn connected with pressure gauge and switch and connected with two ends of marsh gas pipeline, and other one is connected to air bag through a switch.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a sealing-free segmental cover-uncovering type straw marsh gas pool.    Fermenting tank (1)    Feeding port (2)    Water pressure tank (11)    Ring beams (12)    Discharge hole (21)