Scroll Pump Fluid Recirculation Valve Pressure Relief
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Solution Overview
Problem
Scroll pumps with loaded axial seals face issues of high internal pressures leading to potential 'lift-off' of the orbiting scroll, causing radial leakage and increased wear on seals, which can be mitigated by relieving pressure through a fluid recirculation mechanism.
Innovation Solution
Incorporating a fluid recirculation channel and valve that activates when a pressure differential exceeds a certain threshold, reducing internal pressure and allowing fluid flow back to the inlet, thereby reducing the biasing force required to maintain contact between the scrolls, using a biasing apparatus like springs to bias the orbiting scroll against the fixed scroll via axial seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If loaded axial seals are used between the scrolls, then sealing performance is improved, but internal pressure increases causing scroll lift-off and radial leakage
Solution Approach 1:
A fluid recirculation channel is introduced as an intermediary pathway between the high-pressure space and the inlet. This channel allows excess fluid to recirculate back to the inlet, mediating the pressure build-up by providing an alternative flow path that prevents pressure from reaching levels that would cause scroll lift-off while maintaining the sealing function of the axial seals
2Reliability
If high biasing force is applied to maintain scroll contact, then sealing is improved, but wear on seals increases
Solution Approach 1:
The fluid recirculation channel acts as a pressure relief intermediary that prevents excessive pressure build-up in the pumping space. By maintaining more stable and lower operating pressures, the channel reduces the fluctuating loads on the axial seals, thereby extending their operational life while preserving sealing effectiveness
3Stress or pressure
If fluid recirculation channel is added, then pressure relief is improved, but device complexity increases
Solution Approach 1:
The fluid recirculation channel is merged with the existing pump structure by integrating it into either the fixed scroll or the orbiting scroll. This combining approach allows the pressure relief function to be added without requiring separate external components, thereby minimizing the increase in device complexity while achieving effective pressure control
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 risk of scroll lift-off, allows for smaller bearings and lower seal wear, and facilitates the use of an exhaust check valve, enhancing pump performance and reliability.
Implementation Method 1
The biasing apparatus may comprise one or more springs
Implementation Method 2
The fluid recirculation valve is configured to switch from the closed state to the open state when a pressure differential across the fluid recirculation valve is equal to or exceeds a certain threshold value
Data Source
AI summary
A scroll pump includes an inlet and an outlet, a fixed scroll and an orbiting scroll intermeshed with each other, wherein the fixed scroll and orbiting scroll define a space therebetween. The scroll pump further includes a biasing apparatus configured to bias the orbiting scroll against the fixed scroll, a fluid recirculation channel which extends from the space to the inlet through either the fixed scroll or the orbiting scroll, and a fluid recirculation valve disposed in the fluid recirculation channel. The fluid recirculation valve is configured to permit flow of fluid from the space to the inlet through the fluid recirculation channel or to block flow of fluid through the fluid recirculation channel. The fluid recirculation valve is configured to switch from a closed state to an open state when a pressure differential across the fluid recirculation valve is equal to or exceeds a certain threshold value.