BIOGAS SYSTEM

1. Biogas system comprising an elongated tank forming an elongated internal digester chamber, wherein in its longitudinal direction the tank comprises in series a front end section, multiple intermediate sections and a back section that bound the digestion chamber, wherein the front end section, the intermediate sections and the back section comprises flanges that are coupled against each other.

2. Biogas system according to claim 1, wherein the intermediate sections comprise multiple intermediate segments which are positioned in series around the longitudinal axis of the tank, wherein at the meeting ends the intermediate segments comprise flanges that are coupled against each other.

3. Biogas system according to claim 2, wherein the intermediate segments comprise a deformable seal strip that is formed as one unity with the flange, wherein the deformable strip extends oblique from the flange with its distal end towards the digestion chamber.

4. Biogas system according to any one of the preceding claims, comprising an expansion chamber above the top tank half that is separated from the digestion chamber and that is in fluid connection with the digestion chamber via an outlet channel.

5. Biogas system according to claim 4, wherein the expansion chamber is open at the upper side.

6. Biogas system according to claim 5, wherein in horizontal direction the open upper side is larger than the outlet channel.

7. Biogas system according to any one of claims 4-6, wherein the expansion chamber is bounded by a circumferential wall that extends upright from the tank.

8. Biogas system according to claims 5 and 7, wherein the circumferential wall comprises a free extending upper edge that bounds the open upper side of the expansion chamber .

9. Biogas system according to claim 7 or 8, wherein the circumferential wall comprises wall segments that are coupled against each other.

10. Biogas system according to claim 9, wherein the transitions between the wall segments coincide with the transitions between the intermediate sections.

11. Biogas system according to any one of the claims 4-10, wherein the tank comprises an upper wall that bounds the upper side of the digestion chamber and the lower side of the expansion chamber, wherein the outlet channel extends downwards from the upper wall into the digestion chamber .

12. Biogas system according to claims 2 and 12, wherein in vertical direction the flanges at the meeting ends of the intermediate sections all extend below the lowest end of the outlet channel.

13. Biogas system according to any one of the claims 4-12, wherein the tank comprises an upper wall that bounds the upper side of the digestion chamber, and an inlet channel that extends downwards from the upper wall into the digestion chamber, wherein the inlet channel is spaced apart from the outlet channel in the longitudinal direction of the tank.

14. Biogas system according to claims 4 and 13, wherein the outlet channel is separated from the expansion chamber .

15. Biogas system according to claim 14, wherein the outlet channel is upwardly extended by a circumferential wall that is located inside the expansion chamber.

16. Biogas system according to claims 4 and 13, wherein in downward direction the inlet channel extends deeper inside the digestion chamber than the outlet channel.

17. Biogas system according to any one of the preceding claims, wherein the intermediate tank sections form a cylindrical circumferential wall of the tank.

18. Biogas system according to any one of the preceding claims, wherein the tank comprises a top tank half and a bottom tank half having horizontally extending flanges that are coupled against each other, wherein the top tank half comprises in series a front top segment, multiple intermediate top segments and a back top segment having vertically extending flanges that are coupled against each other, wherein the bottom tank half comprises in series a front bottom segment, multiple intermediate bottom segments and a back bottom segment having vertically extending flanges that are coupled against each other.

19. Biogas system according to claim 18, wherein the intermediate top segments and the intermediate bottom segments are identically formed.

20. Biogas system according to any one of the preceding claims, wherein the sections comprise a continuous insertion chamber along the flanges, wherein the insertion chambers of the coupled flanges are positioned straight opposite each other, wherein a common resilient sealing is inserted in the opposite insertion chambers.

21. Biogas system according to claim 20, wherein the sections comprise a wall section between the flanges, and an U-shaped insertion profile for the sealing between the wall section and its flange, wherein the wall section connects to the back of the U-shaped insertion profile and the flange forms a continuation of one of the legs of the U- shaped insertion profile.

22. Biogas system according to claim 20 or 21, wherein the resilient sealing comprises an elongated base strip having sealing flaps along the length of the base strip that extend sideways from the base strip.

23. Biogas system according to claim 22, wherein the base strip and the sealing flaps are in cross section configured as arrow heads that point outside.

24. Biogas system according to any one of the preceding claims, wherein the flanges are coupled by multiple couplings that are evenly distributed along the flanges, wherein the couplings comprise a coupling pin having a coupling head and a coupling shaft extending from the coupling head, wherein the flanges comprise sets of aligned holes wherein the coupling shaft is inserted.

25. Biogas system according to claim 24, wherein the couplings comprise a wedge having two wedge legs to accommodate the coupling shaft in between, wherein the wedge legs and the coupling shaft comprise a series of locking edges that incline with respect to the longitudinal axis of the shaft.

26. Biogas system according to claim 25, wherein the locking edges are barbed shaped to enable the accommodation of the shaft between the wedge legs and to counteract disengagement.

27. Biogas system according to any one of claims

24-26, wherein the coupling head has a convex shape and is configured to be biased towards a flatter shape when the wedge is tightened.

28. Biogas system according to any one of claims 24-27, wherein the couplings are made of plastic, preferably

HDPE.

29. Biogas according to any one of the preceding claims, wherein the sections or segments are made of plastic, preferably HDPE. o-o-o-o-o-o-o-o-

FG/HZ