Scroll Compressor Variable Back-Pressure Control

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Solution Overview

Problem

Existing scroll compressors lack an adjustable counter-pressure system, leading to inefficient operation and performance losses due to fixed contact pressures, which are not optimized for varying operating pressures and speeds.

Innovation Solution

Incorporating at least two passages in the displacement scroll that temporarily create a fluid connection between the counter-pressure chamber and compression chambers, allowing for adjustable pressure in the counter-pressure chamber based on high and low pressures, thereby optimizing contact pressure and ensuring tightness without excessive force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed counter-pressure chamber is used in scroll compressors, then the structure is simple, but the contact pressure cannot be optimized for varying operating pressures and speeds, leading to performance losses

Engineering Contradiction:
Improveadaptability to varying operating pressuresVSAvoidcomplexity of pressure adjustment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the counter-pressure chamber pressure variable rather than fixed. The counter-pressure chamber is connected to compression chambers through passages that allow pressure to equalize dynamically during operation. This enables the contact pressure between spirals to adapt automatically to varying operating conditions, resolving the contradiction between adaptability and simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the pressure parameter in the counter-pressure chamber from a fixed value to a variable value that responds to operating conditions. By connecting the counter-pressure chamber to compression chambers via passages, the pressure in the counter-pressure chamber changes in response to compression chamber pressure variations, enabling automatic optimization of contact pressure without complex control systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If excessive contact pressure is applied to ensure tightness between spirals, then sealing is improved, but energy losses increase due to excessive force requirements

Engineering Contradiction:
Improvesealing tightness between spiralsVSAvoidenergy loss from excessive contact pressure
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements feedback by connecting the counter-pressure chamber to the compression chambers through passages. The pressure in the counter-pressure chamber receives feedback from the compression chamber pressure, automatically adjusting the contact pressure between spirals. This ensures sufficient sealing force is applied only when needed, reducing energy losses from excessive constant pressure while maintaining reliable sealing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by automatically adjusting its own counter-pressure based on operating conditions. The passages allow the compression chamber pressure to directly influence the counter-pressure chamber pressure, creating a self-regulating mechanism that optimizes sealing force without external control, thereby reducing energy consumption while maintaining tightness.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the counter-pressure chamber is isolated from compression chambers, then pressure control is simple, but the system cannot respond to varying operating conditions

Engineering Contradiction:
Improveresponse to varying operating pressuresVSAvoidcomplexity of fluid connection system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the pressure control system into distinct chambers (counter-pressure chamber and compression chambers) connected through specific passages. This segmentation allows independent pressure zones while enabling controlled interaction through the passages, providing adaptability without requiring a completely complex integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The passages serve as intermediaries between the counter-pressure chamber and compression chambers. These passages mediate the pressure interaction, allowing the system to respond to varying operating conditions while maintaining a relatively simple structure. The intermediary passages enable pressure equalization and adaptation without direct complex coupling between chambers.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution enables a variable back-pressure system, allowing for more effective compression by adjusting pressure in the counter-pressure chamber, reducing performance losses and enhancing the efficiency of the scroll compressor across different operating conditions.

Implementation Method 1

at least two passages (60, 61) which temporarily create a fluid connection between said back pressure chamber (50) and at least one of said compression chambers (65a-d)

Methodology Applied
Scientific EffectFluid connection:

Implementation Method 2

With the help of the counter-pressure chamber or with the help of the back-pressure space, it is possible to build up a pressure that acts on the orbiting displacement spiral. A resultant force is generated in the axial direction, whereby the displacement scroll is pressed against the counter-spiral and the spirals are thus sealed off from one another.

Methodology Applied
Scientific EffectPressure force: Pressure Gradient

Data Source

PatentEP3545195B1Spiral-type positive displacement device, method for operating a positive displacement device, positive displacement spiral, vehicle air-conditioning system, and vehicle
Publication Date: 2020.12.30 OET GMBH
  • EP3545195B1 patent drawingFigure 1
  • EP3545195B1 patent drawingFigure 2
  • EP3545195B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a spiral-type positive displacement device, in particular a scroll compressor (10), with a high-pressure region (47) which comprises a high-pressure chamber (40), a low-pressure chamber (30), and an orbiting displacement spiral (31), which engages in a counter spiral (32) in such a way that compression chambers (65a, 65b, 65c, 65d, 65e) are formed between the displacement spiral (31) and the counter spiral (32) to accommodate a working medium, a counter pressure chamber (50) being formed between the low-pressure chamber (30) and the displacement spiral (31). According to the invention, the displacement spiral (31) has at least two openings (60, 61) which at least temporarily produce a fluid connection between the counter pressure chamber (50) and at least one of the compression chambers (65a, 65b, 65c, 65d, 65e), wherein a first opening (60) is formed substantially in a central section (38) of the displacement spiral (31), and at least one second opening (61) is formed in the starting region (37) of the displacement spiral (31).