Scroll Pump Gap Control to Eliminate Tip Seal Wear
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Solution Overview
Problem
Existing scroll pumps face issues with tip seals wearing due to surface friction, generating contaminating dust, and requiring frequent replacement, which is exacerbated by difficulties in accurately setting the spacing between the orbiting and fixed scrolls.
Innovation Solution
A scroll pump with an actuator and sensor system that actively adjusts the axial position of the orbiting and fixed scrolls to control the spacing between them, compensating for thermal variation, wear, and operational loads, allowing for a target spacing to be maintained, even down to less than 20 microns, using capacitive displacement sensors and electromechanical actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tip seals are used to seal against the opposing scroll plate, then axial sealing is provided, but the tip seals are abraded due to surface friction and generate contaminating dust requiring periodic replacement
Solution Approach 1:
The invention removes the tip seals from the system entirely. By actively controlling the axial spacing between the orbiting and fixed scrolls to maintain a precise non-contact gap, the scrolls seal against each other without physical contact, eliminating the need for tip seals and their associated wear and contamination problems
Solution Approach 2:
The invention replaces the mechanical tip seal system with an active control system using sensors and actuators. This electronic control system maintains the optimal spacing between scrolls to achieve sealing through precision positioning rather than through mechanical contact seals, thereby eliminating friction and wear
2Reliability
If the spacing between orbiting and fixed scrolls is set accurately, then tip seal wear is reduced, but it is difficult to set the spacing accurately without tip seals
Solution Approach 1:
The invention implements a feedback control system where sensors continuously measure the actual spacing between the orbiting and fixed scrolls, and this measurement is fed back to the control system which adjusts the actuator to correct any deviations from the target spacing, enabling accurate and maintainable spacing control
Solution Approach 2:
The active control system automatically adjusts and maintains the optimal scroll spacing without requiring manual setup or intervention. The system self-regulates the spacing by continuously monitoring and actuating based on sensor feedback, eliminating the difficulty of manual spacing setup
3Device complexity
If the axial position of scrolls is fixed, then the structure is simple, but thermal variation, wear, and operational loads cause spacing variation affecting performance
Solution Approach 1:
The invention transitions from a static, fixed scroll position to a dynamic, actively controlled position system. The actuator continuously adjusts the axial position of the orbiting scroll based on real-time sensor feedback to compensate for thermal expansion, wear, and operational loads, maintaining optimal spacing under varying conditions
Solution Approach 2:
The invention changes the physical state of the scroll position from fixed to variable. By using the actuator to dynamically adjust the axial spacing parameter in response to sensor measurements, the system adapts to changing operating conditions such as temperature and load variations, maintaining reliable performance
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 reduces the need for tip seals, minimizes wear, and maintains optimal operational performance by dynamically controlling the scroll spacing, enhancing the life and efficiency of the pump.
Implementation Method 1
using capacitive displacement sensors and electromechanical actuators
Data Source
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AI summary
Aspects of the present invention relate to a scroll pump (1; 101). The scroll pump (1; 101) has an axially extending drive shaft (15; 115); a fixed scroll (5; 105); and an orbiting scroll (3; 103). The drive shaft (15; 115) has an eccentric shaft portion (119) on which the orbiting scroll (3; 103) is mounted. The fixed scroll (5; 105) has a fixed scroll wall (11; 111) extending axially from a fixed scroll base (13; 113). The orbiting scroll (3; 103) has an orbiting scroll wall (7; 107) extending axially from an orbiting scroll base (9; 109) towards the fixed scroll (5; 105). At least one sensor (27; 127-n) may optionally be provided for determining a spacing between the orbiting scroll (3; 103) and/or the fixed scroll (5; 105). The scroll pump (1; 101) has at least one actuator (29; 129-n) for adjusting the axial position of the orbiting scroll (3; 103) and/or the fixed scroll (5; 105) in dependence on a determined spacing. Alternatively, or in addition, the scroll pump (1; 101) may be configured to adjust the orientation of the orbiting scroll (3; 103) and/or the fixed scroll (5; 105). Aspects of the present invention also relate to a method of configuring the scroll pump (1; 101).