Compressor Bearing Lubrication via Sequential Flow Paths
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Solution Overview
Problem
Current compressor systems face reliability concerns at low operating speeds due to inadequate lubrication of bearings, leading to potential metal-to-metal contact and energy efficiency losses, as the viscosity of the refrigerant-oil mixture is reduced, causing out-gassing and increased viscosity issues.
Innovation Solution
A compressor assembly with a dual lubricant flow path system that supplies a mixture of lubricant and refrigerant to bearings, with varying amounts of out-gassed refrigerant and viscosity, ensuring adequate lubrication even at lower speeds by sequentially providing lubricant to discharge and inlet bearings, thereby maintaining a separating film and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If compressor speed is reduced to improve energy efficiency, then energy consumption decreases, but bearing lubrication becomes inadequate leading to metal-to-metal contact
Solution Approach 1:
The lubrication system is segmented into multiple independent flow paths, each dedicated to specific bearings. This allows tailored lubrication strategies for different bearings, ensuring adequate lubrication even at reduced compressor speeds where traditional single-path systems fail.
Solution Approach 2:
Different flow paths provide different lubricant conditions (viscosity, flow rate) to different bearings based on their specific requirements. The system applies local quality by matching lubrication characteristics to the specific needs of each bearing location and operating condition.
2Ease of operation
If refrigerant-oil mixture viscosity is reduced to improve lubrication flow, then lubrication delivery improves, but separating film between bearing surfaces becomes insufficient
Solution Approach 1:
The system dynamically adjusts lubricant viscosity through temperature control and flow rate management. By controlling the thermal state and flow characteristics of the lubricant in different paths, the system optimizes the balance between deliverability and film-forming capability under varying operating conditions.
Solution Approach 2:
The system changes key parameters of the lubricant (temperature, viscosity, flow rate) to achieve optimal performance. By adjusting these parameters independently in different flow paths, the system maintains adequate separating films while ensuring proper lubrication delivery.
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
Enables reliable operation at lower speeds without energy efficiency losses, as the increased viscosity of lubricant prevents metal-to-metal contact and maintains efficient compressor performance.
Implementation Method 1
Bearing operation introduces viscous losses that result in heating of the lubricant
Implementation Method 2
The resulting increase in lubricant temperature may cause out-gassing of some refrigerant. In addition, mechanical agitation of the lubricant as it passes through bearings can also cause cavitation which results in refrigerant out-gassing
Implementation Method 3
inadequate lubrication of the compressor elements such as bearings may present a problem at low operating speeds. Speed dependent reliability concerns arise because damaging contact may occur between two surfaces in close proximity depending on their relative speed and the viscosity of the lubricant between them
Data Source
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AI summary
A compressor assembly is provided including a housing assembly. A first rotor and a second rotor are arranged within the housing assembly. The first rotor is supported for rotation by a first inlet bearing adjacent an inlet end of the housing assembly and by a first discharge bearing adjacent a discharge end of the housing assembly. The second rotor is supported for rotation by a second inlet bearing adjacent the inlet end of the housing assembly and by a second discharge bearing adjacent the discharge end of the housing assembly. A first lubricant flow path is configured to supply lubricant to more than one of the first discharge bearing, the first inlet bearing, the second discharge bearing, and the second inlet bearing generally sequentially.