NOVELTY - The gas purification device comprises a cooling chamber in which tube condenser coil is disposed. The tube condenser coil has an inlet end having a feed line for discharge of unpurified biogas and an exit end connected with a separator device. The separator device is arranged below the tube condenser coil in a cooling chamber so that water vapor contained in the unpurified biogas/fermentation gas with impurities in the tube condenser coil is condensed. A condensate in the separator device is separated from the purified biogas/fermentation gas.    USE - The device is useful for purifying biogas from a biogas plant or fermentation gas from a sewage treatment plant (claimed).    ADVANTAGE - The device economically purifies the biogas from the biogas plant or fermentation gas from the sewage treatment plant without using additional energy supply.    DETAILED DESCRIPTION - The gas purification device comprises a cooling chamber in which tube condenser coil is disposed. The tube condenser coil has an inlet end having a feed line for discharge of unpurified biogas and an exit end connected with a separator device. The separator device is arranged below the tube condenser coil in a cooling chamber so that water vapor contained in the unpurified biogas/fermentation gas with impurities in the tube condenser coil is condensed. A condensate in the separator device is separated from the purified biogas/fermentation gas, which is removed from a clean gas outlet of the separator device. The cooling chamber is configured to cool the condensate and positioned below a ground floor level at a depth of greater than or equal to 1.5 m. The tube condenser coil is helically or spirally arranged with horizontal turns, which extend in the cooling chamber over a height of 1.2 m. The purification device further comprises an air vent tube for introducing cooling air into the cooling chamber, a fireplace (2) arranged above the tube condenser coil, through which the tube condenser coil is heated, and a waste-heat heater arranged above the tube condenser coil and below the fireplace. The air vent tube is provided with an upper end for sucking ambient air from outside and a lower end opening into a bottom region of the cooling space where the cooling air exits. The waste-heat heater is operated with waste heat radiators or a gas compressor. The cooling chamber includes a cooling drain pipe (12). The separator device includes a gravel bed space, which is separated from the cooling chamber by a first partition wall. The partition wall has openings, slots or holes for the passage of the condensate from the gravel bed space into the cooling chamber. The gravel bed space has a downwardly projection from a top to bottom, and is separated into equal-sized compartments. The compartments of the gravel bed space comprise a maintenance cover. A cleaning outlet is arranged in a wall of the cooling chamber in a bottom region below the drain pipe.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic sectional view of a gas purification device.    Fire place (2)    Separator device (4)    Gas tube (6)    Gas filter (10)    Drain pipe. (12)