Submersible Agitator Sealing Ring for In-Place Seal Replacement

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Solution Overview

Problem

Existing submersible agitators in biogas plants require complex and costly disassembly processes for mechanical seal replacement, leading to potential biogas leakage and production loss.

Innovation Solution

An additional sealing ring is provided on the propeller side of the agitator shaft, allowing the mechanical seal to be replaced without disassembling the agitator shaft by moving the sealing ring from an operating position to an exchange position, ensuring the seal is maintained during the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the mechanical seal is replaced by disassembling the flange and agitator shaft, then the mechanical seal can be accessed and replaced, but the disassembly process is complex and time-consuming, leading to increased costs and potential biogas loss

Engineering Contradiction:
Improvemechanical seal replacementVSAvoiddisassembly and reassembly time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The mechanical seal is segmented from the agitator assembly by providing separate access to the seal without requiring disassembly of the flange or agitator shaft. The seal can be independently removed and replaced while the agitator remains in place.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediary access mechanism is provided that allows the mechanical seal to be accessed and replaced without directly disassembling the flange and agitator shaft. This intermediary structure enables seal replacement while maintaining the integrity of the main agitator assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of repair

If the flange is disassembled to replace the mechanical seal, then the seal can be replaced, but biogas leakage occurs during the disassembly process and production is lost

Engineering Contradiction:
Improvemechanical seal replacementVSAvoidbiogas loss
Core Design Contradiction:
Ease of repairVSLoss of substance

Solution Approach 1:

The mechanical seal is designed to be accessible and replaceable before any disassembly that would compromise the fermenter seal. The seal replacement procedure is structured to occur while the fermenter remains sealed and operational, preventing biogas loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An intermediary access system allows the mechanical seal to be replaced without breaking the seal of the fermenter. This intermediary mechanism enables maintenance work on the seal while the main containment remains intact, preventing substance loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of repair

If the agitator shaft is disassembled to replace the mechanical seal, then the seal can be accessed, but the complex disassembly and reassembly process increases costs

Engineering Contradiction:
Improvemechanical seal replacementVSAvoiddisassembly process complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The mechanical seal is segmented as an independently accessible component that can be replaced without disassembling the agitator shaft or other complex components. This segmentation simplifies the repair process by isolating the seal replacement to a specific, accessible location.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanical seal is extracted as a separately replaceable component that can be removed and replaced without taking out or disassembling the agitator shaft. This extraction approach reduces device complexity by allowing the seal to be serviced independently.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4678278A1Agitator, in particular a submerged agitator
Publication Date: 2026.01.14 PTM GMBH
  • EP4678278A1 patent drawingFigure 1
  • EP4678278A1 patent drawingFigure 2
  • EP4678278A1 patent drawingFigure 3

AI summary

The invention relates to an agitator, and in particular a submersible agitator, and preferably a side-entry submersible agitator, as a component of a fermenter in a biogas plant. The agitator is fundamentally equipped with an agitator shaft (3) with at least one agitator propeller (4) attached to one end of it. It also includes a drive (5) for the agitator shaft (3) at its other end. Furthermore, a flange (2) is provided, surrounding and supporting the agitator shaft (3) with an intermediate mechanical seal (7). According to the invention, a sealing ring (8) is additionally provided on the propeller side, enclosing the agitator shaft (3) and radially overlapping the mechanical seal (7). This sealing ring has at least one operating position spaced axially from the flange (2) and an exchange position for the mechanical seal (8) in contact with the flange (2).