Scroll Pump Axial Lip Seal High-Speed Leakage
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Solution Overview
Problem
Existing scroll pumps face challenges with shaft seal wear and leakage due to high rotational speeds, particularly in smaller pumps, where traditional radial shaft seals are prone to quick abrasion and require frequent replacement, especially when dealing with significant pressure differentials.
Innovation Solution
The implementation of an axial lip seal between the orbiting and fixed scrolls, which provides a sealing force that increases with pressure differential, effectively resisting fluid and gas leakage, and is less susceptible to abrasion due to reduced relative movement compared to traditional shaft seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional radial shaft seals are used in smaller scroll pumps operating at high rotational speeds, then the pump can maintain compact size and high speed operation, but the shaft seals wear quickly and require frequent replacement
Solution Approach 1:
The patent changes the sealing mechanism from radial shaft seals to an axial seal lip configuration. The seal lip is positioned axially between the orbiting and fixed scrolls, creating a sealing interface that is less susceptible to abrasion from high-speed rotation. This parameter change in sealing geometry fundamentally alters the wear characteristics while maintaining compatibility with high rotational speeds
Solution Approach 2:
The invention transitions from radial sealing (perpendicular to shaft rotation) to axial sealing (parallel to shaft rotation). The seal lip extends axially between the scrolls, creating a sealing surface that moves minimally during operation. This dimensional change reduces the relative movement and friction between sealing surfaces, thereby extending seal life at high speeds
2Device complexity
If traditional radial shaft seals are used, then the pump structure can be simplified, but leakage increases under significant pressure differentials
Solution Approach 1:
The patent modifies the sealing approach by using an axial seal lip that presses against the orbiting scroll with a force that increases with pressure differential. This parameter change in sealing mechanics ensures that as pressure difference increases, the seal tightens rather than loosens, effectively preventing leakage without requiring complex additional components
Solution Approach 2:
The invention extracts the sealing function from the traditional radial shaft seal location and implements it separately as an axial seal lip between the scrolls. This separation allows the sealing mechanism to be optimized independently for pressure differential resistance, using the pressure force itself to enhance sealing effectiveness
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 axial lip seal significantly reduces leakage and extends replacement intervals, maintaining effective sealing performance even at high rotational speeds and varying pressure conditions, enhancing the operational reliability of smaller scroll pumps.
Implementation Method 1
the sealing force is for resisting leakage of fluid from outside the scroll mechanism into the flow path, and the lip seal is configured such that when there is an increase in pressure differential across the seal due to a reduction in pressure within the scroll pump the sealing force is increased
Data Source
Figure 1
Figure 2~3
AI summary
The present invention provides a scroll pump comprising: a scroll mechanism having an orbiting scroll and a fixed scroll; a drive shaft having a concentric shaft portion and an eccentric shaft portion connected to the orbiting scroll. The shaft is arranged to be driven by a motor so that rotation of the shaft imparts an orbiting motion to the orbiting scroll relative to the fixed scroll for pumping fluid along a flow path from an inlet to an outlet of the scroll mechanism. An axial lip seal is located between the orbiting scroll and the fixed scroll for resisting leakage of fluid from outside the scroll mechanism into the flow path.