Scroll Compressor Back-Pressure Sealing With Timed Port Overlap
Solution Overview
Problem
Existing scroll compressors face challenges in maintaining a sufficient pressure in the counter-pressure chamber to ensure a fluid-tight seal between the displacement spiral and the counter-spiral without causing excessive frictional forces that lead to performance losses.
Innovation Solution
A positive displacement machine with a high-pressure chamber, low-pressure chamber, and a counter-pressure chamber, featuring centrally arranged outlet openings and strategically positioned through-openings that temporarily overlap with the counter-pressure chamber during specific angular ranges of the orbiting displacement spiral, allowing for efficient pressure generation and fluid connection without excessive friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure in the counter-pressure chamber is increased to press the displacement spiral against the counter-spiral for fluid-tight sealing, then the sealing reliability is improved, but frictional forces increase causing performance losses
Solution Approach 1:
The first through-opening is positioned to temporarily overlap with the outlet opening in advance, allowing the counter-pressure chamber to be pressurized before the displacement spiral completes its orbiting motion. This preliminary pressure buildup ensures sealing contact is established without requiring continuously high pressure that would cause excessive friction during the entire rotation cycle.
2Loss of energy
If the pressure in the counter-pressure chamber is kept low to minimize frictional forces, then energy efficiency is improved, but the fluid-tight seal between the displacement spiral and counter-spiral cannot be maintained
Solution Approach 1:
The system employs periodic pressure action where the first through-opening temporarily overlaps with the outlet opening during specific angular ranges (45° to 65° of the rotation angle) to build up pressure in the counter-pressure chamber. This periodic pressurization maintains sealing reliability only when needed, rather than maintaining continuously high pressure that would cause constant frictional losses.
3Stress or pressure
If the first through-opening is positioned to overlap with the outlet opening for extended periods, then pressure generation in the counter-pressure chamber is improved, but the orbiting movement of the displacement spiral is restricted due to increased friction
Solution Approach 1:
The first through-opening is designed to overlap with the outlet opening only partially during a limited angular range (45° to 65°) of the displacement spiral's rotation. This partial overlap provides sufficient pressure generation in the counter-pressure chamber to ensure sealing, while limiting the duration of high friction exposure to prevent excessive restriction of the orbiting movement speed.
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 design minimizes performance losses by optimizing pressure generation in the counter-pressure chamber, ensuring a fluid-tight seal while maintaining efficient orbiting movement of the displacement spiral, resulting in a more compact and cost-effective compressor design.
Implementation Method 1
at least the first through-opening is arranged in the region of the outlet opening, so that during operation the first through-opening and the outlet opening temporarily overlap at least partially
Implementation Method 2
The pressure in the back-pressure chamber exerts a force on the displacer spiral, pressing it against the counter-spiral, so that the two spirals are fluid-tightly sealed against each other
Data Source
Figure 1
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AI summary
The invention relates to a scroll-type positive displacement machine, in particular a scroll compressor, comprising a high-pressure chamber (11), a low-pressure chamber (12), an orbiting displacement spiral (13), a counter spiral (14), and a counter-pressure chamber (15) which is located between the low-pressure chamber (12) and the displacement spiral (13), wherein an outlet opening (16), through which a compressed working medium flows into the high-pressure chamber (11) during operation, is centrally arranged in the counter spiral (14) in a high-pressure region, and wherein the displacement spiral (13) has at least a first and a second passage opening (17a, 17b) for fluidic connection to the counter-pressure chamber (15), wherein at least the first passage opening (17a) is arranged in the region of the outlet opening (16) so that, during operation, the first passage opening (17a) and the outlet opening (16) temporarily overlap at least in sections.