Biogas Fermenter Height Adjustment via Wrap-Around Chain Drive
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Solution Overview
Problem
Biogas plant height adjustment devices using rope winches are prone to corrosion, mechanical stress, and operational failures, leading to frequent shutdowns and production outages due to rope breakages, incomplete mixing, and safety concerns.
Innovation Solution
A wrap-around drive with a traction chain or articulated chain that is guided around deflection elements, providing stability and preventing mechanical stress, allowing for reliable and efficient assembly adjustment within the fermenter tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rope winch is used as a height adjustment device, then the assembly can be adjusted in height, but the rope is subjected to corrosion and mechanical stress leading to frequent breakages
Solution Approach 1:
The rope is extracted from the corrosive fermenter tank environment by positioning the rope drum outside the tank. The rope passes through a gastight seal in the tank wall, allowing the assembly to be raised and lowered while keeping the rope drum and most of the rope in the safe, corrosion-free external environment. This extraction eliminates the primary corrosion issue that caused rope breakages.
Solution Approach 2:
Instead of winding the rope onto a drum inside the tank (conventional approach), the invention inverts the arrangement by placing the rope drum outside the tank and having the rope extend into the tank through a sealed opening. This inversion reverses the exposure relationship, protecting the rope from corrosion while maintaining height adjustment functionality.
2Length of moving object
If a large rope drum is used to accommodate long rope lengths, then the rope can be wound sufficiently, but the drum does not fit through standard servicing orifices
Solution Approach 1:
The rope drum is positioned in the external environment outside the fermenter tank, utilizing the third dimension of space outside the tank rather than being constrained to the internal tank space. This dimensional relocation allows the drum to be sized appropriately for long rope accommodation while remaining accessible through external service openings, eliminating the fit-through-problem.
3Device complexity
If the rope is wound onto the rope drum inside the fermenter tank, then no gastight rope leadthrough is needed, but contaminants are drawn up on the rope and wound around the drum causing blockages
Solution Approach 1:
The rope drum is extracted from the contaminant-filled fermenter tank environment and positioned externally. The rope passes through a minimal gastight seal, keeping the drum and majority of the rope in the clean external environment. This extraction prevents contaminants from being drawn up onto the rope and wound around the drum, eliminating blockage issues.
4Device complexity
If a rope is used as traction means, then the device is simple, but the rope is flexurally slack and incapable of making desired guidance stability available
Solution Approach 1:
The invention changes the physical parameters of the traction means by using an articulated chain instead of a flexible rope. The chain maintains simplicity of operation while providing dimensional stability and guidance rigidity, as the articulated structure prevents lateral buckling and ensures stable guidance during assembly lowering and raising operations.
Data Source
AI summary
A biogas plant contains a fermenter vessel, in which an assembly support is mounted, preferably vertically oriented. An assembly, in particular a submersible motor driven stirrer, is retained by a height adjustment device so as to be vertically adjustable on the assembly support. Accordingly, the height adjustment device is formed by a belt drive of which a traction device is guided around at least two deflecting elements spaced apart from one another in the longitudinal direction of the assembly support. At least one of the deflecting elements can be driven in rotation by a driving device and the assembly is coupled to the traction device in such a way that when the deflecting element is rotationally actuated in a first direction the assembly is raised and when the deflecting element is rotationally actuated in a second, opposite direction, the assembly is lowered.