Scroll Compressor Back-Pressure Porting for Seal-Friction Balance
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Solution Overview
Problem
Existing scroll compressors face challenges in maintaining a balance between sufficient pressure to ensure a fluid-tight seal between the displacer spiral and the counter-spiral while minimizing frictional forces that hinder the orbiting movement, requiring significant design effort to optimize pressure generation.
Innovation Solution
A positive displacement machine with a high-pressure chamber, low-pressure chamber, and a back-pressure chamber, featuring a through-opening in the displacer spiral that temporarily connects to both compression chambers during operation, allowing pressure to be generated efficiently without additional fluid connections, thus reducing friction and enabling a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure in the back-pressure chamber is increased to press the displacer spiral against the counter-spiral for fluid-tight sealing, then the sealing reliability is improved, but the frictional forces increase which slow down the orbiting movement and cause power loss
Solution Approach 1:
The invention introduces a dynamic pressure regulation mechanism where the pressure in the back-pressure chamber is no longer constant but varies periodically during the compression cycle. The through-opening in the displacer spiral dynamically connects the back-pressure chamber to different compression chambers at different phases, causing the back-pressure to fluctuate in sync with the compression process. This dynamic pressure variation allows the sealing force to be sufficient only when needed while reducing friction during other phases, thereby resolving the contradiction between reliable sealing and energy efficiency.
2Stress or pressure
If additional fluid connections are added to the back-pressure chamber to optimize pressure generation, then the pressure control is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The through-opening in the displacer spiral serves multiple functions simultaneously: it provides fluid communication between compression chambers and the back-pressure chamber, acts as a pressure regulation mechanism, and eliminates the need for separate dedicated pressure control connections. By making this single structural element multi-functional, the invention achieves effective pressure control without adding complexity or additional fluid connections, thus resolving the contradiction between pressure optimization and device simplicity.
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 minimizes frictional forces on the orbiting movement of the displacer spiral, ensures a fluid-tight seal, and reduces manufacturing complexity and costs by eliminating the need for additional fluid connections, thereby enhancing performance and efficiency.
Implementation Method 1
The back-pressure chamber serves to build up pressure. 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.
Implementation Method 2
the orbiting movement of the positive displacement spiral causes the through-opening to be temporarily located at least partially in the first compression chamber and subsequently at least partially in the second compression chamber
Data Source
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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), the displacement spiral (13) engaging in the counter spiral (14) in such a way that, during operation, at least a first and a second compression chamber (16a, 16b) for receiving a working medium are temporarily formed, and the displacement spiral (13) having at least one passage opening (17) for fluidic connection to the counter-pressure chamber (15), wherein the passage opening (17) is located in the displacement spiral (13) in such a manner that, during operation, due to the orbiting movement of the displacement spiral (13), at least sections of the passage opening (17) are temporarily arranged in the first compression chamber (16a) and subsequently at least sections of the passage opening are temporarily arranged in the second compression chamber (16b).