Scroll Pump Tip Seal Segmentation for Leakage and Dust Control
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Solution Overview
Problem
Existing scroll pumps suffer from tip seal wear and dust generation, leading to back leakage and frequent replacement, which increases manufacturing costs and contamination risks, especially in clean environments like vacuum chambers.
Innovation Solution
Implementing multiple discrete sealing arrangements along the scroll walls with varying sealing characteristics, such as size, material, and presence of tip seals, tailored to local conditions like pressure differentials and wear rates, to optimize sealing effectiveness and reduce tip seal dust and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tip seals are used to prevent back leakage, then sealing effectiveness is improved, but tip seal wear and dust generation increase
Solution Approach 1:
The scroll wall is divided into multiple sealing arrangements with different characteristics. The first sealing arrangement uses a tip seal received in a channel, while the second sealing arrangement uses the axial end face of the scroll wall itself. This segmentation allows each sealing arrangement to perform different functions - the tip seal provides primary sealing while the axial end face provides secondary sealing without generating dust.
Solution Approach 2:
Different sealing characteristics are applied at different locations along the scroll wall. The first sealing arrangement (tip seal in channel) is used where higher sealing pressure is needed, while the second sealing arrangement (axial end face) is used where dust generation must be minimized. This local differentiation optimizes both sealing effectiveness and dust reduction.
2Reliability
If tip seals are used to prevent back leakage, then sealing effectiveness is improved, but manufacturing costs increase
Solution Approach 1:
The sealing system is segmented into two arrangements - one with tip seals and one without. This allows the more expensive tip seal solution to be used only where absolutely necessary, while reducing tip seal usage overall, thereby lowering manufacturing costs while maintaining adequate sealing effectiveness.
Solution Approach 2:
The invention accepts that tip seals are consumable components that will wear over time. By using fewer tip seals (only in the first sealing arrangement) and combining them with a non-consumable second sealing arrangement, the overall cost of ownership is reduced.
3Ease of manufacture
If uniform sealing characteristics are used along the scroll wall, then manufacturing is simplified, but local sealing performance is suboptimal
Solution Approach 1:
The invention explicitly applies different sealing characteristics at different locations along the scroll wall. The first sealing arrangement (with tip seal in channel) provides different sealing characteristics than the second sealing arrangement (axial end face). This local differentiation ensures optimal sealing performance at each location while maintaining reasonable manufacturing simplicity.
4Reliability
If tip seal width is increased to improve sealing, then back leakage is reduced, but power consumption increases
Solution Approach 1:
The sealing function is segmented between two arrangements - the tip seal in the channel and the axial end face. This segmentation allows back leakage control to be achieved through the combined action of both arrangements rather than requiring a single wide tip seal, thereby reducing the friction and power consumption associated with oversized seals.
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 approach enhances back-leakage control, reduces tip seal dust, decreases maintenance needs, and lowers manufacturing costs by optimizing sealing performance and material usage, while minimizing contamination risks in sensitive environments.
Implementation Method 1
there is a small axial gap between an axial end of the tip seal and the base of the channel so that in use fluid occupying the gap forces the tip seal axially towards the base plate of the orbiting scroll. Accordingly, the tip seal is supported on a cushion of fluid which serves to urge the seal against an opposing scroll.
Data Source
Figure 1
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AI summary
The present application relates to a scroll compressor comprising a scroll pumping mechanism which comprises an orbiting scroll (20) having an orbiting scroll wall (34) extending axially from an orbiting scroll plate (36) towards a fixed scroll (22) and a fixed scroll having an fixed scroll wall (28) extending axially from a fixed scroll plate (30) towards the orbiting scroll. The compressor further comprises an axially extending drive shaft (14) having an eccentric shaft portion (16) so that rotation of the eccentric shaft portion imparts an orbiting motion to the orbiting scroll relative to the fixed scroll for pumping fluid from an inlet (24) to an outlet (26) of the pumping mechanism. An axial end portion of one of the scroll walls (28, 34) has a first sealing arrangement and a second sealing arrangement arranged in series along the scroll wall from the inlet to the outlet for sealing between the axial end portion of the scroll wall and the scroll plate of the opposing scroll, said first sealing arrangement having first sealing characteristics which are selected according to sealing requirements local to the first sealing arrangements and said second sealing arrangement having second sealing characteristics which are selected according to sealing requirements local to the second sealing arrangements, and said first sealing characteristics are different from said second sealing characteristics.