Compressor Lubricant Supply via Pressure Differential
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Solution Overview
Problem
Existing screw compressors with roller element bearings are too large and costly for HVAC&R applications, and there is a need for a cost-effective fluid machine that minimizes friction while allowing precise rotor positioning and alignment.
Innovation Solution
A fluid machine design that uses a casing with a sump containing lubricant, where a pressure differential supplies lubricant to dynamic interfaces between rotors, eliminating the need for roller element bearings and utilizing the casing surfaces as bearings, with lubricant passages and recesses optimized for efficient lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roller element bearings are used to precisely position rotors and minimize friction, then rotor positioning precision and friction reduction are improved, but the fluid machine becomes too large and costly for HVAC&R applications
Solution Approach 1:
The patent extracts and eliminates the roller element bearings from the system, replacing them with a lubricated surface contact system between the shafts and casing. This removal of unnecessary components directly reduces the overall size and cost while maintaining the essential function of rotor positioning and friction minimization through the lubricant film.
Solution Approach 2:
The system uses the pressure differential generated during normal operation to automatically supply lubricant to the dynamic interfaces. This self-lubrication mechanism eliminates the need for external bearing components and complex lubrication systems, allowing the machine to maintain precise rotor positioning without additional size or cost.
2Force
If roller element bearings are used to minimize friction during high speed operation, then friction is reduced, but the fluid machine becomes too large and costly
Solution Approach 1:
The lubrication system is designed to automatically supply lubricant to the dynamic interfaces using the pressure differential generated during operation. This self-service approach minimizes friction without requiring complex external bearing systems or additional control mechanisms, thereby reducing device complexity while maintaining low friction performance.
Solution Approach 2:
The patent utilizes the hydraulic pressure differential generated during compressor operation to deliver lubricant to the shaft-casing interfaces. This hydraulic approach replaces mechanical bearing systems, reducing both friction and overall system complexity by using the machine's own operating conditions to enable effective lubrication.
3Manufacturing precision
If roller element bearings are used for precise rotor positioning, then rotor alignment is improved, but the fluid machine becomes unacceptable large and costly
Solution Approach 1:
The patent removes the expensive roller element bearings and replaces them with a simpler lubricated surface contact system. This extraction of costly components directly reduces manufacturing cost while the precision shaft-casing fit combined with lubricant film maintains the necessary rotor alignment for effective operation.
Solution Approach 2:
The invention changes the lubrication parameters by using pressure differential-driven lubricant supply to the dynamic interfaces. This parameter change enables precise rotor positioning and alignment through the lubricant film, achieving manufacturing precision requirements without the need for expensive bearing components.
4Productivity
If a pressure differential is used to supply lubricant to dynamic interfaces, then lubrication efficiency is improved and pumps or control valves are eliminated, but the system requires optimized passages and recesses
Solution Approach 1:
The lubrication system is designed to automatically supply lubricant to the dynamic interfaces using the pressure differential generated during normal operation. This self-service mechanism improves lubrication efficiency by ensuring lubricant is delivered exactly where and when needed, without requiring external pumps or control valves, while the passage configuration integrates seamlessly into the existing machine structure.
Solution Approach 2:
The patent merges the lubrication system with the existing pressure differential mechanism already present in the compressor operation. By combining the compression-induced pressure differential with the lubricant supply function, the system achieves high lubrication efficiency without adding separate pump or control valve systems, integrating the lubrication passages and recesses into the existing machine architecture.
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 design provides a compact, cost-effective solution with reduced friction and precise rotor alignment, utilizing the pressure differential for lubricant supply, eliminating the need for pumps or control valves and ensuring stable lubrication across a range of shaft speeds.
Implementation Method 1
A pressure differential created within the fluid machine supplies the lubricant from the sump to the first lubricant passage and the second lubricant passage simultaneously
Implementation Method 2
a first lubricant passage for supplying lubricant from the sump to a dynamic interface associated with the first rotor, and a second lubricant passage for supplying lubricant from the sump to a dynamic interface associated with the second rotor
Data Source
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AI summary
A fluid machine includes a first rotor rotatable about a first axis, a second rotor rotatable about a second axis, a casing for supporting said first rotor and said second rotor, a sump having a volume of lubricant contained therein, a first lubricant passage for supplying lubricant from the sump to a dynamic interface associated with the first rotor, and a second lubricant passage for supplying lubricant from the sump to a dynamic interface associated with the second rotor. A pressure differential created within the fluid machine supplies the lubricant from the sump to the first lubricant passage and the second lubricant passage.