Scroll Pump Tip Seal Wear Reduction via Segmented Design
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Solution Overview
Problem
Existing scroll pump tip seal arrangements experience excessive wear and leakage due to continuous pressure and thermal expansion, leading to reduced sealing efficiency and frequent replacement needs.
Innovation Solution
A tip seal arrangement with discrete energized portions fixed at spaced locations along the first spiral region, allowing axial and radial movement to reduce wear and accommodate thermal changes, while maintaining sealing efficiency by constraining axial movement at these locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tip seal is continuously pressed against the opposing scroll to maintain sealing efficiency, then sealing performance is improved, but tip seal wear increases excessively
Solution Approach 1:
The tip seal is designed to dynamically adjust its position between the first and second spiral regions based on operating conditions. The seal can move axially to engage with the opposing scroll when high sealing is required, and retreat to the grooved region when wear reduction is prioritized, enabling adaptive operation rather than continuous pressing
Solution Approach 2:
The tip seal arrangement is divided into distinct functional regions: a first spiral region for sealing engagement, a grooved region for wear protection and thermal management, and a second spiral region for additional sealing. This segmentation allows different portions of the seal to perform different functions at different times, reducing overall wear while maintaining sealing efficiency
2Duration of action of moving object
If the tip seal is fixed in position to reduce wear, then wear is decreased, but sealing efficiency deteriorates due to inability to accommodate thermal expansion
Solution Approach 1:
Different regions of the tip seal have different properties: the grooved region provides thermal management and wear protection, while the spiral regions provide sealing engagement. The seal structure transitions from a uniform fixed design to a differentiated design where each region serves its specific function, allowing thermal expansion accommodation in the grooved region while maintaining sealing in the spiral regions
Solution Approach 2:
The tip seal's axial position is changed as a variable parameter rather than being fixed. The seal can move axially to adjust for thermal expansion and contraction, and the grooved region provides a mechanism for controlled movement and positioning, allowing the seal to adapt to changing thermal conditions while maintaining reliable sealing
3Adaptability or versatility
If the tip seal allows movement to accommodate thermal variations, then thermal accommodation is improved, but wear increases due to continuous pressing
Solution Approach 1:
The tip seal employs dynamic movement between fixed positions rather than continuous pressing. The seal can move axially to accommodate thermal expansion and contraction, and the grooved region provides a mechanism for controlled movement and positioning, allowing the seal to adapt to changing thermal conditions while maintaining reliable sealing
Solution Approach 2:
The tip seal operates in periodic cycles of engagement and disengagement. During operation, the seal moves into the first spiral region to seal, then retreats to the grooved region during low-load or shutdown periods to reduce wear. This periodic action pattern allows thermal accommodation while significantly reducing cumulative wear compared to continuous pressing
4Reliability
If the tip seal is completely floating to maintain sealing across the entire spiral region, then sealing efficiency is improved, but wear becomes excessive in the first spiral region
Solution Approach 1:
The tip seal is segmented into multiple functional regions along its axial length: a first spiral region for sealing engagement, a grooved region for wear protection and thermal management, and a second spiral region for additional sealing. This segmentation allows different portions of the seal to perform different functions at different times, reducing overall wear while maintaining sealing efficiency
Solution Approach 2:
Different regions of the tip seal have different properties and functions. The grooved region provides thermal management and wear protection, while the spiral regions provide sealing engagement. The seal structure transitions from a uniform floating design to a differentiated design where each region serves its specific function, allowing the seal to maintain efficiency while reducing wear in critical areas
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 solution significantly reduces tip seal wear and leakage, extending the seal's lifespan and maintaining sealing efficiency by distributing wear evenly and accommodating thermal variations, thus reducing maintenance intervals.
Implementation Method 1
The tip seal of a sealing arrangement is generally fixed relative to the axial end portion at spaced apart fixing locations along the spiral extent of the tip seal arrangement to resist axial movement of the tip seal at the fixing locations
Implementation Method 2
there exists a gas pressure difference between two adjacent pockets 208. In Figure 2, the pressure in the pockets 208 on one side of a scroll wall is different from the pressure on an opposing side of the scroll creating a pressure gradient
Implementation Method 3
Existing scroll pump tip seal arrangements experience excessive wear and leakage due to continuous pressure and thermal expansion
Data Source
AI summary
The present invention relates to a scroll pump (10) comprising two scrolls (20, 22) which are co-operable for pumping fluid from an inlet (24) to an outlet (26) on relative orbiting motion of the scrolls. Each scroll comprises a scroll base (30, 36) from which a spiral scroll wall (28, 34) extends generally axially towards the base of the opposing scroll. The pump comprises a tip seal arrangement comprising an axial end portion of one or both of the scroll walls which locates a tip seal (508) for resisting the passage of pumped fluid across the or both scroll walls between the or both scroll walls and the scroll base of the opposing scroll. The tip seal arrangement limits axial movement of the tip seal towards the scroll base of the opposing scroll along a first spiral region (507) of the or both scrolls between the inlet and the outlet.