Floating Scroll Seal Retaining Ring Startup Pressure

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Solution Overview

Problem

Existing scroll compressors face issues with pressure imbalance during startup, causing the seal to be ejected from its jacket due to the initial pressure differential between the high-pressure and low-pressure chambers, leading to potential seal degradation and operational instability.

Innovation Solution

A floating seal arrangement is introduced between the fixed scroll body and the separator plate, featuring a seal retaining ring that limits axial movement of the seal member, allowing for axial motion while maintaining sealing engagement, and a method of applying differential pressures to trap the seal member during startup, preventing ejection and enhancing sealing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional seal arrangement is used in scroll compressors, then the seal can move axially to compensate for thermal expansion and manufacturing tolerances, but the seal may be ejected from its jacket during startup due to pressure imbalance

Engineering Contradiction:
Improveaxial movement capabilityVSAvoidseal retention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A seal retaining ring is introduced as an intermediary component between the seal and the circular hub. The retaining ring has an inner diameter that fits over the seal member and an outer diameter that contacts the circular hub, creating a mechanical intermediary structure that prevents axial ejection while allowing controlled movement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the seal is constrained to prevent ejection, then seal retention is improved, but the seal cannot compensate for thermal expansion and manufacturing tolerances

Engineering Contradiction:
Improveseal retentionVSAvoidaxial movement capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The seal arrangement is designed with dynamic characteristics, allowing axial movement within controlled limits. The floating seal can move axially to compensate for thermal expansion and manufacturing tolerances, while the retaining ring prevents excessive movement that would cause ejection, creating a dynamically balanced system

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the seal is allowed to move axially during startup, then it can accommodate pressure differential, but the seal may degrade due to excessive movement

Engineering Contradiction:
Improvepressure differential accommodationVSAvoidseal integrity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The seal retaining ring provides preliminary anti-action by preventing axial ejection before excessive movement can occur. During startup, when pressure differential is highest, the retaining ring counteracts the ejection force, protecting the seal from degradation while still allowing controlled movement for pressure accommodation

Inventive Principle:
Principle #9Preliminary anti-action

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 floating seal arrangement effectively mitigates seal ejection and degradation by allowing for axial movement and compensating for thermal expansion and manufacturing tolerances, ensuring reliable sealing and improved operational stability during startup and transient pressure states.

Implementation Method 1

a seal spring positioned within the resilient seal jacket

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

At startup, the pressure below the seal is higher than the pressure above the seal for a short period of time. This pressure imbalance causes the seal to move up

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2839161B1Floating scroll seal with retaining ring
Publication Date: 2018.01.31 BITZER KUEHLMASCHINENBAU GMBH
  • EP2839161B1 patent drawingFigure 1
  • EP2839161B1 patent drawingFigure 2
  • EP2839161B1 patent drawingFigure 3

AI summary

A scroll compressor that includes a housing and scroll compressor bodies disposed in the housing as well as a method of operation thereof is provided. The housing is separated into different chambers by a separator. One of the scroll bodies is sealed to the separator with a floating seal arrangement including a seal interface between a floating seal of the floating seal arrangement and a hub of a fixed scroll compressor body. A seal retaining ring prevents axial motion of a seal member of the seal interface during start-up operations due to pressure imbalances across the seal member.