Abstract: An apparatus for casting concrete wall elements, which together form a wall, running along a curvature at least in sections, of a container, in particular of a fermenter for biogas plants, comprising a horizontal foundation, to which several horizontally extending bounding elements are attached, which between them form fields to be cast with concrete, several formwork elements, which are detachably secured to at least a few bounding elements, which form formwork surfaces, which are opposite each other in a field and which are aligned at an angle with respect to the vertical, which in the erected state form the face side surfaces of adjacent wall elements, that face each other, wherein the formwork elements each have at the formwork surfaces at least one receiving device, and wherein at least one end of at least one reinforcing element to be cast in the concrete is secured in each receiving device of formwork surfaces, which are opposite each other in a field.

Abstract: A container wall for storing and fermenting materials, comprising a clamping channel, having an undercut near the upper edge that is open for clampingly receiving a rim of at least one plastic foil that covers the container at the top, the clamping channel comprises a narrowed lateral insertion slot with an upper and a lower protrusion, to which the foil can be wrapped around. A lower wall of the clamping channel is wider than the thickness of the clamping rail at the facing longitudinal edge which is formed as a flat profile, the upper wall of the clamping channel is at least twice as wide as the thickness of the clamping rail. The insertion profile can be inserted into the clamping channel through the entry. When the foil that is wrapped around the insertion profile is under tension, the insertion profile is retained in the clamping channel by the protrusions.

Abstract: A tower (1) for wind power installations, on which at least one rotor (2) that can be driven by wind can be rotatably supported, has an especially low mass relative to its load-bearing capacity, stability, and rigidity, if it has a tower portion (3), tapering toward the top, with a bulging outer wall (4) that is convex in longitudinal section.