TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The invisible multi-grade balance gas of pneuma biogas tank, where the tank wall of the tank body (4) and the tank bottom of connecting part is a smooth arc-shaped transition. The invisible multi-grade balance gas of methane pneuma, where set with stop valve, check valve at the corresponding position of each branch tube, and the each branch tube in the air inlet end opening of collecting pneuma room downward or inclined downwards. The invisible multi-grade balance of marsh gas tank, where the pneuma corresponding to a discharging port and feeding port on the tank body of the two relative end, bottom of the tank body from the feeding port by a discharge hole (5) is gradually low of slopeshaped. The tank bottom of the tank body distribute through a heating tube (6). The invisible multi-stage balance gas pneuma biogas tank, where the marsh gas tank is set with a penjiao mechanism, which comprise a jet stirring group, lower spraying stirring group, the exit end of the pool body and connected a biogas slurry pump, jet stirring the group, lower spraying stirring group corresponding to a transfusion tube connecting the pump of exit end, a jet stirring the group, lower spraying stirring group set with to two more than a nozzle inner inclined in a marsh gas tank. The invisible multi-grade balance gas of methane pneuma, where a jet stirring the group of nozzle is in the beam of arched pneuma room above liquid level following middle, injection direction is upward, a lower stirring spraying group of nozzle is in the pool bottom or near bottom tank of tank wall and the arched tank bottom, inclined nozzle a toward the slope. The invisible multi-grade balance gas of methane pneuma, where a partition board by reinforced concrete. The contact multi-level balance gas methane pneuma, where penjiao mechanism of each water branch is set with a three-way stop valve, water inlet pipe set with stop valve, water discharging valve.