Scroll Pump Lubricant-Free Anti-Rotation Device
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Solution Overview
Problem
Existing scroll pumps face contamination issues due to lubricant leakage from bearings into the high vacuum region, especially under high pressure differentials, making them unsuitable for clean environments without additional sealing complications.
Innovation Solution
A compact scroll pump design with a lubricant-free anti-rotation device made of flexible plastics in the high vacuum region and bearing arrangement in the low vacuum region, minimizing pressure differential and preventing lubricant leakage, while a counter-weight balances the orbiting components and reduces the eccentric shaft diameter for increased compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bearings are used to support the shaft in the high vacuum region, then the shaft is properly supported, but lubricant leaks into the high vacuum region causing contamination
Solution Approach 1:
The patent extracts the bearing arrangement from the high vacuum region and relocates it to the low vacuum region. This separates the lubricated component (bearing) from the clean vacuum environment, eliminating the source of contamination while maintaining shaft support functionality through the eccentric shaft mechanism.
Solution Approach 2:
The pump is segmented into two distinct vacuum regions: a high vacuum region containing the scroll chambers and a low vacuum region containing the bearing arrangement. This segmentation allows different vacuum levels and contamination requirements to be satisfied in different zones of the same device.
2Object-affected harmful factors
If a bellows arrangement is used to isolate bearings from the high vacuum region, then lubricant contamination is prevented, but the device complexity increases
Solution Approach 1:
Instead of using a bellows arrangement to isolate bearings within the high vacuum region, the patent extracts the entire bearing arrangement to the low vacuum region. This eliminates the need for complex bellows sealing structures while achieving the same contamination prevention goal.
3Stability of the object's composition
If the counter-weight is located in the high vacuum region, then the orbiting components are balanced, but the pump size increases
Solution Approach 1:
The patent relocates the counter-weight from the traditional axial position to a radial position adjacent to the scroll plate. This dimensional change allows the counter-weight to balance the orbiting components while occupying minimal space within the existing pump footprint, achieving balance without increasing overall pump volume.
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
Effectively prevents lubricant contamination in the high vacuum region, reducing leakage and allowing the scroll pump to operate in clean environments without additional sealing issues, while achieving a more compact design.
Implementation Method 1
a lubricant free anti-rotation device is located in the high vacuum region for resisting rotation of the orbiting scroll and allowing said orbiting motion... the anti-rotation device is made from a flexible plastics material comprising a central body portion from which two pairs of opposing arms extend, wherein the first pair flex to allow movement of the orbiting scroll relative to the housing in a first direction and the second pair flex to allow movement of the orbiting scroll relative to the housing in a second direction generally orthogonal to the first direction
Implementation Method 2
A scroll pump which... a cap sealing a high vacuum region from a low vacuum region... In view of the high pressure differential across the bearings, some leakage may still occur into the high vacuum region of the pump
Implementation Method 3
a bearing arrangement for supporting rotation of the concentric shaft portion and eccentric shaft portion is located in the low vacuum region
Implementation Method 4
a counter-weight for balancing the weight of the orbiting components of the pump... wherein the counter-weight is located in the low vacuum region and adjacent to the scroll plate of the orbiting scroll
Data Source
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AI summary
The present invention relates to a scroll pump (10) comprising a pump housing (12), a drive shaft having a concentric shaft portion (14) and an eccentric shaft portion (16) connected to an orbiting scroll (20). The shaft is arranged to be driven by a motor (18) so that during use rotation of the shaft imparts an orbiting motion to the orbiting scroll relative to a fixed scroll (22) for pumping fluid between a pump inlet (24) and pump outlet (26) of the compressor. The fixed scroll has an opening through which the shaft extends and is connected to the orbiting scroll on an opposing side of the fixed scroll to the motor. A high vacuum region is located on an orbiting scroll side of the scroll arrangement and a low vacuum region is located generally on a fixed scroll side of the scroll arrangement. A lubricant free anti-rotation device (52) is located in the high vacuum region for resisting rotation of the orbiting scroll and allowing said orbiting motion, and a bearing arrangement (34, 36) for supporting rotation of the concentric shaft portion and eccentric shaft portion is located in the low vacuum region.