Rotary Compressor Liquid Injection Cooling
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Solution Overview
Problem
Existing rotary compressor designs face limitations in achieving high pressure ratios and efficient cooling, particularly for near-isothermal compression, due to mechanical stress, leakage, and inefficiencies associated with liquid injection and sealing issues.
Innovation Solution
A positive displacement rotary compressor design that incorporates a rotor with a cycloidal and constant radius profile, balanced by counterweights, and a gate system for efficient compression, along with atomized liquid injection into the compression chamber to enhance heat transfer and maintain near-isothermal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid injection is used for cooling in rotary compressors, then heat transfer efficiency is improved, but mechanical stress and sealing issues worsen
Solution Approach 1:
The patent applies local quality by introducing a liquid-tolerant rotor design with specific surface treatments and sealing geometries at the compression chamber interface, allowing liquid injection for cooling while maintaining reliable sealing. The rotor incorporates localized modifications such as hydrophobic coatings and optimized land geometries that prevent liquid penetration into sealing clearance areas.
Solution Approach 2:
The patent uses an intermediary approach by introducing a liquid-tolerant sealing system that acts as a mediator between the liquid injection cooling system and the compression chamber. This intermediary sealing mechanism allows liquid coolant to be injected for heat transfer while preventing it from compromising the sealing function through specialized sealing geometries and materials.
2Device complexity
If traditional rotary compressor designs are used, then device complexity is reduced, but pressure ratio capability worsens
Solution Approach 1:
The patent applies dynamics by implementing a liquid-tolerant rotor design that dynamically adapts to liquid injection conditions. The rotor incorporates flexible sealing elements and dynamic clearance control mechanisms that maintain effective sealing under varying liquid coolant conditions, enabling high pressure ratio operation while preserving the simplicity of rotary compressor architecture.
Solution Approach 2:
The patent uses parameter changes by modifying key rotor parameters such as surface hydrophobicity, sealing land geometries, and clearance dimensions to optimize performance under liquid injection. These parameter modifications enable the rotor to tolerate liquid coolant while maintaining the pressure ratio capability needed for high-pressure applications.
3Productivity
If high speed operation is used, then productivity is improved, but vibration and noise worsen
Solution Approach 1:
The patent applies the counterweight principle by incorporating balanced rotor designs with counterbalancing elements that offset the centrifugal forces generated during high-speed operation. This counterbalancing reduces vibration and noise while maintaining the high productivity associated with high-speed compression operations.
Solution Approach 2:
The patent implements prior cushioning by incorporating vibration-damping elements and noise-reduction features in the rotor and housing design before operation begins. These preemptive cushioning measures, such as compliant sealing elements and damping materials, mitigate vibration and noise during high-speed operation while preserving productivity.
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 achieves high pressure ratios with reduced vibration and noise, efficient energy use, and effective sealing, allowing for the compression of gases and liquids while minimizing the risk of hydrolock and improving overall compressor efficiency.
Implementation Method 1
atomized liquid injection into the compression chamber to enhance heat transfer and maintain near-isothermal conditions
Implementation Method 2
injected cooling liquid...absorbs heat, and is directed toward the outlet valve
Implementation Method 3
compressing a working fluid using the compressor...a pressure ratio of the compressor is at least 15:1
Implementation Method 4
applying force to a drive shaft that is driving the compression process
Data Source
AI summary
A positive displacement rotary compressor is designed for near isothermal compression, high pressure ratios, high revolutions per minute, high efficiency, mixed gas/liquid compression, a low temperature increase, a low outlet temperature, and/or a high outlet pressure. Liquid injectors provide cooling liquid that cools the working fluid and improves the efficiency of the compressor. A gate moves within the compression chamber to either make contact with or be proximate to the rotor as it turns.