Compressor Rotor Internal Lubricant Passageways
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Solution Overview
Problem
Existing HVAC&R systems with screw compressors face efficiency reduction due to lubricant mixing with the fluid in the compression chamber, leading to increased wear on components and higher maintenance costs, particularly from axial forces on thrust bearings.
Innovation Solution
The implementation of internal lubricant passageways within the rotors of the compressor to direct lubricant between the intake and discharge portions, reducing the need for external conduits and minimizing lubricant mixing with the fluid, while applying a counter-force to reduce axial force on thrust bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricant is directed into the compressor for cooling, lubrication, and sealing, then compressor performance is improved, but lubricant mixes with fluid in the compressor reducing HVAC&R system efficiency
Solution Approach 1:
The compressor is divided into separate functional zones with dedicated lubricant delivery paths. The lubricant is segmented into specific delivery locations (thrust bearing, journal bearing, rotor surfaces) rather than being freely mixed in the compression chamber, achieving both lubrication and prevention of fluid contamination
Solution Approach 2:
The harmful mixing of lubricant with compressed fluid is extracted and eliminated by providing separate lubricant delivery pathways. The lubricant is taken out of the main compression flow path and delivered through dedicated ports and passages to specific components, preventing contamination of the refrigerant or process fluid
2Reliability
If external conduits are used to direct lubricant, then lubrication is provided, but device complexity increases
Solution Approach 1:
The lubricant delivery system is merged with the rotor structure itself. The rotor incorporates internal passages and features that serve as lubricant conduits, eliminating the need for separate external tubing or conduits. The rotor body integrates multiple functions: compression, rotation, and lubricant distribution
Solution Approach 2:
The rotor serves multiple functions simultaneously: it compresses the fluid through its lobes and grooves, rotates to drive the compression cycle, and acts as a lubricant distribution system through its internal passages and surface features. This multi-functionality reduces overall system complexity by eliminating dedicated lubricant delivery components
3Temperature
If lubricant is directed through the compressor, then cooling and sealing are improved, but wear on thrust bearings increases due to axial forces
Solution Approach 1:
A balance piston is implemented to counteract the axial forces generated during compression. The balance piston receives lubricant and uses it to create a counterbalancing pressure that offsets the axial thrust on the thrust bearing, reducing wear and extending bearing life while maintaining effective cooling
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 enhances compressor efficiency, decreases wear on thrust bearings, and reduces maintenance costs by minimizing the impact of vibrations and axial forces, thereby extending the operational life of the compressor.
Implementation Method 1
The internal passageway is configured to direct a lubricant between the intake portion and the discharge portion of the compressor housing
Implementation Method 2
The gaps form a continuous compression chamber that communicates with a compressor inlet or port and continuously reduces a volume of the fluid as the rotors turn to compress the fluid
Implementation Method 3
lubricant may be directed into the compressor for cooling, lubrication, and/or sealing
Implementation Method 4
lubricant may be directed into the compressor for cooling, lubrication, and/or sealing
Data Source
AI summary
A system includes a compressor housing having an intake portion and a discharge portion and a rotor disposed in the compressor housing and configured to compress a fluid flowing from the intake portion toward the discharge portion. The rotor includes a body portion and an internal passageway formed within the body portion extending along an axial length of the rotor. The internal passageway is configured to direct a lubricant between the intake portion and the discharge portion of the compressor housing.