Active-Flushed Double Seal for Gear Pump Oxygen Exclusion

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Solution Overview

Problem

Existing sealing arrangements for gear pumps in polymerization reactors are inefficient in preventing oxygen ingress, leading to quality deterioration of polymers and safety risks, while being costly and difficult to maintain due to excessive nitrogen consumption and leakage issues.

Innovation Solution

A sealing arrangement with a recess between two seals, actively flushed with an inert medium like nitrogen or silicone oil, ensuring a constant flow or pressure to maintain a closed gas circuit and detect leaks, allowing for targeted sealing and monitoring to prevent oxygen penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plant components are encased in a protective housing flooded with ultra-pure nitrogen, then oxygen ingress is prevented, but manufacturing cost increases and maintenance accessibility deteriorates

Engineering Contradiction:
Improveoxygen exclusionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing arrangement is divided into multiple independent sealing points (first seal at medial perimeter, second seal at lateral perimeter) rather than using a single encasing housing. This segmentation allows oxygen exclusion at critical interfaces without requiring complete encasement of the gear pump, reducing manufacturing complexity and cost while maintaining reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the essential function of oxygen exclusion from the complex encasement concept and implements it through localized sealing elements at specific interfaces. The sealing arrangement takes out only the necessary sealing function from the full encasement approach, eliminating unnecessary housing structures and nitrogen flooding requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If complete conveyor system is encased to prevent nitrogen leakage, then oxygen exclusion is improved, but device complexity increases and maintenance difficulty increases

Engineering Contradiction:
Improveoxygen exclusionVSAvoidencasement structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of a single complex encasement structure, the invention segments the sealing function into multiple discrete sealing points located at critical interfaces within the gear pump. This allows oxygen exclusion without requiring a complete conveyor system encasement, significantly reducing device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the essential sealing function from the complex encasement concept and implements it through localized sealing elements. This eliminates the need for complex encasement structures while maintaining the oxygen exclusion function.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If large amounts of ultra-pure nitrogen are used for flushing, then oxygen ingress is prevented, but nitrogen consumption increases and loss of substance worsens

Engineering Contradiction:
Improveoxygen exclusionVSAvoidnitrogen consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The sealing arrangement is pre-configured with optimal sealing geometries and positions that prevent oxygen ingress before flushing is needed. This preliminary sealing action reduces the amount of nitrogen required for flushing compared to systems that rely on continuous or excessive nitrogen flow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the approach from using large amounts of nitrogen flow to using controlled, minimal flushing through precisely positioned seals. By altering the sealing parameters (positions, geometries) rather than increasing nitrogen quantity, the system achieves better oxygen exclusion with reduced nitrogen consumption.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The sealing arrangement effectively prevents oxygen ingress, reduces nitrogen consumption, and enhances maintenance accessibility by detecting leaks and maintaining a controlled environment, thus ensuring polymer quality and safety without the need for extensive encasement.

Implementation Method 1

the recess can be connected to a source with a flushing medium in such a way that the recess can be actively flushed with the flushing medium

Methodology Applied
Scientific EffectFluid flow through recess:

Data Source

PatentEP2820247B1Sealing arrangement, a conveying device having a sealing arrangement and a method for operating the sealing arrangement
Publication Date: 2021.02.17 MAAG PUMP SYST TEXTRON
  • EP2820247B1 patent drawingFigure 1~2
  • EP2820247B1 patent drawingFigure 3
  • EP2820247B1 patent drawingFigure 4

AI summary

The invention relates to a sealing arrangement (1) for conveying devices, in particular for gear pumps, in which an inner space (5) can be sealed off from an outer space (6), wherein the sealing arrangement comprises at least two parts (2, 3) each having at least one sealing surface (20, 21), wherein the sealing surfaces (20, 21) comprise: a first seal (11) along a first, medial perimeter of the sealing surface (20, 21), a second seal (12) along a second, lateral perimeter of the sealing surface (20, 21), a recess (15) between the first seal (11) and the second seal (12), characterized in that the recess (15) can be connected to a source (30) of a flushing medium such that the recess (15) can be actively flushed with the flushing medium.