Single-layer biogas roofs without storage function
The suitable tank covering without storage for each tank and each working pressure
The outer membrane is leak-proof and bears external loads
In the first place, single-layer, gas-proof tank coverings of biogas plants serve to seal up the tank. Gas has to be accumulated and air must be prevented from entering the tank. External loads are for the most part wind, snow and other climatic conditions. Overpressure and low pressure act from inside. The layout of the covering must take these loads into account.
Working pressure
The working pressure determines the shape of the covering.
- Spherical coverings are suitable for highest pressures.
- Cylindrical coverings are suitable for low pressures of up to 5 mbar.
- Biaxially arched shapes are ideal for pressureless systems.
The pressure inside the gas system is limited by overpressure and low pressure safety valves.
Coverings for gas systems with gas pressure obtain their stability through the overpressure inside the gas chamber which pre-stresses the membrane and bears the external loads. In the case of operating conditions with no gas pressure, the central tower serves as a support against external loads.
Ideally, coverings for pressureless systems come in a biaxially arched shape. When stretched over the central tower, the membrane obtains the stability required to prevent it from fluttering and pumping in the wind. This contributes substantially to the longevity of biogas roofs.
With the help of clamping rails the membrane is clamped to the tank in such a way that it is leak-proof and will never tear out.
Membrane material
Membranes are made of polyester fabrics which are PVC-coated on both sides. Different membrane types are used depending on static requirements, statutory provisions and customer requirements.