Plug Flow Fermenter Agitator Control With Traction-Force Sensing
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Solution Overview
Problem
Existing fermenter vessels in biogas plants lack reliable mechanisms for adjusting the height of agitators, detecting end positions, and recognizing floating or sinking layers, leading to inefficiencies in the fermentation process.
Innovation Solution
Incorporating a traction force measuring device to directly or indirectly measure the traction force on the traction cable, allowing for precise height adjustments and detection of floating or sinking layers, with automatic shutdowns and adaptive control measures based on traction force thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fill level measuring device is used to detect substrate level, then the agitator can be lowered to ensure complete immersion of agitator blades, but neither shutdown at end positions nor recognition of floating/sinking layers is possible
Solution Approach 1:
A traction force measuring device acts as an intermediary between the agitator height adjustment system and the control system. This device measures cable tension to indirectly detect end positions and substrate layers, providing information that the direct fill level measuring device could not obtain.
Solution Approach 2:
The patent replaces direct mechanical position sensing with a force-based measurement system. Instead of using complex position sensors or visual detection systems, the solution uses a traction force measuring device to detect cable tension changes, which correlate with agitator position and substrate conditions.
2Adaptability or versatility
If the agitator height is continuously adjustable via cable pulley motor drive, then flexible positioning is achieved, but automatic shutdown at end positions and detection of floating/sinking layers is not possible
Solution Approach 1:
The traction force measuring device provides continuous feedback on cable tension to the control system. When the agitator reaches end positions or encounters floating/sinking layers, the cable tension changes, triggering automatic shutdown or adaptive control measures. This feedback loop enables both flexible positioning and reliable detection.
3Device complexity
If no traction force measurement is implemented, then the system is simpler, but shutdown at end positions and determination of layer thickness/consistency is not possible
Solution Approach 1:
The traction force measuring device serves as a simple intermediary component that provides rich measurement information without requiring complex sensor systems. By measuring cable tension, it indirectly determines end positions, layer thickness, and consistency with minimal additional hardware.
Data Source
AI summary
The invention relates to a fermenter vessel (1) of a biogas plant, having at least one height-adjustable agitator (8), wherein the agitator (8), in the fermenter vessel (1), is guided with a guide element (17) on a guide rail (9) oriented approximately vertically in a vertical axis direction and is held in height-adjustable fashion by means of a traction cable (10). According to the invention, a traction force measuring device (22; 25) is provided for directly and/or indirectly measuring the traction force on the traction cable (10) in accordance with a cable tension, such that, by means of the traction force measuring device (22; 25), in the case of a preferably controlled height adjustment of the agitator (8), varying traction force measurement signals are generated in accordance with varying traction forces and are supplied to an evaluation device (20).