Turbo Compressor Back Pressure Control for Thrust Reduction
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Solution Overview
Problem
Conventional turbo compressors face challenges in achieving high compression efficiency and minimizing size due to complex structures and compression losses, particularly when multiple impellers are installed in a facing configuration, which increases thrust and reduces reliability, and in a sequential configuration, which increases size and thrust bearing load.
Innovation Solution
The design incorporates a back pressure space on the rear surface of the impellers and a back pressure control valve to manage thrust and reduce the load on thrust bearings, allowing for a compact size and enhanced efficiency by attenuating thrust and heat generation through the use of a back pressure control system that adjusts according to compressor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple impellers are installed in a facing configuration, then compression efficiency is improved, but thrust increases and reliability decreases
Solution Approach 1:
The patent introduces a back pressure control valve that creates a counteracting back pressure force to balance the thrust generated by the impellers. This counterweight mechanism reduces the net thrust on the rotor, preventing rotor backward movement and improving reliability while maintaining compression efficiency through multi-stage impeller configuration.
2Volume of moving object
If multiple impellers are installed in a sequential configuration, then size is reduced, but thrust increases and reliability decreases
Solution Approach 1:
The back pressure control valve generates a back pressure force that counteracts the cumulative thrust from sequentially arranged impellers. This allows the compressor to maintain a compact sequential configuration while preventing rotor overload and backward movement, thereby improving reliability without increasing size.
3Reliability
If a back pressure control valve is added, then thrust is reduced and reliability is improved, but device complexity increases
Solution Approach 1:
The back pressure control valve is designed to automatically regulate back pressure based on the pressure differential between the discharge side and suction side. The valve self-adjusts according to operating conditions without requiring external control systems, reducing complexity while maintaining thrust balance and reliability.
Solution Approach 2:
The control valve changes the back pressure parameter dynamically based on operating conditions. By adjusting the back pressure level according to the pressure differential, the system maintains optimal thrust balance across different operating points, improving reliability without requiring complex mechanical adjustments.
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 configuration effectively reduces thrust and frictional losses, enhances compression efficiency, and maintains reliability while minimizing the size of thrust bearings, allowing for a smaller and more efficient turbo compressor without the need for additional cooling devices.
Implementation Method 1
a turbo compressor capable of centrifugally-compressing a refrigerant by rotating an impeller
Implementation Method 2
a back pressure control valve to manage thrust and reduce the load on thrust bearings, allowing for a compact size and enhanced efficiency by attenuating thrust
Data Source
AI summary
A turbo compressor is provided that may include an impeller housing having an impeller accommodation space, an inlet formed at a first side of the impeller accommodation space, and an outlet formed at a second side of the impeller accommodation space that communicates with the inlet; an impeller accommodated in the impeller accommodation space of the impeller housing, rotated together with a rotary shaft by being coupled to the rotary shaft, and configured to centrifugally-compress a fluid suctioned through the inlet of the impeller housing and discharge the compressed fluid outside of the impeller housing through the outlet; a back pressure space formed between a rear surface of the impeller and the impeller housing; a back pressure passage connected between the outlet of the impeller housing and the back pressure space; and a back pressure control valve installed between the back pressure passage and the back pressure space, and configured to selectively open and close a region therebetween.