Cover for manure pit for generating bio-gas

摘要

The cover system for containers open at the top, esp. manure pits for generating biogas, has at least two films (3,4) over each other secured with a gas-tight seal round the edge (2) of the pit. The upper film (3) is held outwards at a constant gas pressure of more than 1 atmos. to give it a stiff outwards convex profile. A sepd. intermediate chamber (5), with a variable gas volume, is between the lower film (4) and the convex-expanded outer film. The outer film (3) is pref. a double film (6) with pref. flexible distance pieces (11) such as bubble film with a constant gas pressure of at least more than 1 atmos. in the spaces (9) between the walls (7,8) of the distancers, while the double film is curved stiffly outwards. A pressure-controlled connection is between the intermediate chamber (5) and the outer atmos.. At least one of the film materials (3,4,7,8) has a heat reflective surface, such as a mirrored surface, on the side towards the biogas pit. The outer (3) and inner (4) foils are assembled at the edge (2) of the pit or tank, on a protective underlay, and wound at least twice round the sealing edge and an angled profile to be secured by at least one further clamping ring.