Pivoting Guide Mast for Biogas Agitator Maintenance

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Solution Overview

Problem

Existing lifting and swiveling devices for biogas fermenter tanks are mechanically complex, expensive, and maintenance-intensive, with issues related to cable sealing, accessibility, and ease of use, particularly when pivoting the guide mast and maintaining the submersible agitator.

Innovation Solution

A gas-tight bearing journal tube is mounted pivotably in a stationary cover plate, with a cable seal and deflection elements, allowing the guide mast to pivot widely while maintaining a sealed and accessible cable winch arrangement, using a structurally simple and cost-effective design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a turntable solution is used to enable the cable passage to pivot with the guide mast, then the cable can run unhindered during pivoting, but the mechanical complexity and cost increase significantly

Engineering Contradiction:
Improvecable run during pivotingVSAvoidturntable mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the cable seal from the rotating turntable mechanism and places it directly in the stationary cover plate. The cable seal remains fixed while the guide mast pivots, eliminating the need for a complex turntable structure while still allowing the cable to run unhindered during pivoting operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of making the cable passage rotate with the mast (turntable approach), the patent inverts the approach by keeping the cable seal stationary in the cover plate while allowing the mast to pivot around it. This reversal simplifies the mechanism while achieving the same operational goal.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the guide mast is mounted in a turntable at the fermenter ceiling height, then the cable can pivot freely, but the agitator cannot be lifted out for maintenance

Engineering Contradiction:
Improvecable pivoting capabilityVSAvoidagitator accessibility
Core Design Contradiction:
Ease of operationVSEase of repair

Solution Approach 1:

The patent removes the turntable mechanism from the ceiling area, eliminating the obstruction that prevented agitator removal. The cable seal is extracted and placed in the stationary cover plate, allowing the guide mast to pivot freely while the agitator can be completely removed from the fermenter for maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the cable sealing function from the mast support structure. The cable seal is a separate component in the cover plate, while the guide mast is independently mounted, allowing the mast and agitator to be removed without interfering with the cable sealing arrangement.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If an immersion cup bearing is used for the guide mast, then the mast can pivot, but the maintenance intensity increases significantly

Engineering Contradiction:
Improvemast pivoting capabilityVSAvoidmaintenance intensity
Core Design Contradiction:
Adaptability or versatilityVSEase of repair

Solution Approach 1:

The patent extracts the bearing function from a complex immersion cup structure and replaces it with a simple pivot bearing in the stationary cover plate. This simplified bearing arrangement maintains the mast's pivoting capability while dramatically reducing maintenance requirements and intensity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple, inexpensive pivot bearing that can be easily replaced if needed, rather than a complex immersion cup bearing system. This approach prioritizes ease of replacement over long service life, reducing overall maintenance intensity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If the cable winch is placed inside the dome, then no gas-tight bushings are required, but the cable winch becomes inaccessible for maintenance

Engineering Contradiction:
Improveelimination of gas-tight bushingsVSAvoidcable winch accessibility
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The patent uses the stationary cover plate as an intermediary structure that houses the cable seal. This allows the cable winch to be positioned outside the fermenter where it is easily accessible for maintenance, while the cover plate provides the necessary gas-tight sealing function that would otherwise require complex bushings.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Ease of repair

If a large dome is used to cover the ceiling opening and accommodate the submersible agitator, then the agitator can be accessed, but the dome size and cost increase

Engineering Contradiction:
Improveagitator accessibilityVSAvoiddome size
Core Design Contradiction:
Ease of repairVSVolume of stationary object

Solution Approach 1:

The patent extracts the agitator from the confined dome space and allows it to be completely removed from the fermenter through the ceiling opening. This eliminates the need for a large dome structure, reducing both volume and cost while maintaining full agitator accessibility for maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of providing a dome enclosure to access the agitator, the patent inverts the approach by allowing the agitator to be completely removed from the fermenter. This eliminates the need for a large dome while achieving the same maintenance accessibility goal.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2280060B1Lifting and pivoting device on a guide mast of a fermenter container for a biogas assembly for a height-adjustable submersible device
Publication Date: 2012.09.19 SCHLETTER GMBH
  • EP2280060B1 patent drawingFigure 1
  • EP2280060B1 patent drawingFigure 2~3

AI summary

The lifting and swiveling device is arranged on a vertical guide mast (5) in a digester (1) of a biogas plant. The guide mast (5) is pivotally mounted about its longitudinal axis and carries a vertically adjustable submersible device (3). A height adjustment mechanism (10) is arranged on the upper part (8) of the mast, with a winch (11) for winding and unwinding a cable (12) connected to the submersible device (3) and/or a guide carriage (4) for this purpose. The end of the mast on the upper part (8) is designed as a bearing journal, which is gas-tight and pivotably mounted in a rotary bearing (7) in a stationary and immovable cover plate (19). The winch (11) is located above the cover plate (19) outside the gas space of the digester (1). A gas-tight cable gland (27) with a side seal is included in the longitudinal axis of the bearing journal.The pull rope (12) runs from the winch (11) through the rope guide (27) located in the longitudinal axis into a guide mast interior. From there, the pull rope (12) is guided in the area of ​​the upper mast section (8) with deflection elements attached to it, out of the guide mast interior and further down to the diving apparatus (3) or its guide carriage (4).