Hollow-Shaft Centrifugal Compressor With Process-Gas Motor Cooling
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Solution Overview
Problem
High-speed small centrifugal compressors face high costs due to oil-free bearings, and there is a need for a simplified design to achieve a compact and cost-effective solution.
Innovation Solution
A centrifugal compressor design featuring a vertically arranged shell with a motor assembly, centrifugal compression mechanism, and a guide member that directs pressurized fluid to cool the motor assembly, while using oil-lubricated bearings to reduce axial stress on the rotor shaft and incorporate a compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil-free bearings are used in high-speed centrifugal compressors, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the compressed refrigerant gas itself to cool the motor assembly, eliminating the need for separate cooling systems. The refrigerant flows through channels in the motor housing and rotor, providing self-cooling functionality that reduces overall system complexity while maintaining reliability
Solution Approach 2:
The lubrication oil serves multiple functions: it lubricates the bearings and simultaneously cools the motor assembly. By integrating these functions into a single lubrication system, the patent reduces device complexity while maintaining bearing reliability and motor cooling effectiveness
2Volume of moving object
If a compact centrifugal compressor design is implemented, then volume is reduced, but heat dissipation capability deteriorates
Solution Approach 1:
The motor assembly is nested within the compressor housing, with the rotor positioned inside the stator. The lubrication oil flow paths are integrated within this nested structure, allowing cooling channels to pass through the rotor and motor housing without increasing external dimensions. This nested arrangement enables effective heat dissipation while maintaining a compact overall volume
Solution Approach 2:
The patent uses liquid lubrication oil as a cooling medium, circulating it through channels in the motor housing and rotor to remove heat. This hydraulic cooling approach efficiently dissipates heat from the motor assembly within the compact compressor structure, preventing temperature buildup despite the limited space
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 reduces axial stress on bearings, enables a compact compressor suitable for low-power operations, and effectively cools the motor assembly using the pressurized fluid, addressing the cost and complexity issues of high-speed compressors.
Implementation Method 1
the flow passage is configured such that all of the pressurized fluid from the centrifugal compression mechanism passes through and cools the motor assembly
Implementation Method 2
the centrifugal compression mechanism is arranged downstream of the fluid inlet to receive a fluid, compress and pressurize the fluid, and output the pressurized fluid
Implementation Method 3
use oil-lubricated bearings to reduce axial stress on the rotor shaft
Data Source
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AI summary
A centrifugal compressor and a refrigerating device. The centrifugal compressor includes: a shell, which has a fluid inlet and a fluid outlet; a motor assembly including a stator and a rotor, the rotor including a vertically arranged rotor shaft; a centrifugal compression mechanism, an impeller of which is connected with the rotor shaft so as to be driven by the motor assembly, wherein the centrifugal compression mechanism is arranged downstream of the fluid inlet to receive fluid, compress and pressurize the fluid, and output the pressurized fluid in a direction away from the motor assembly; and a guide member, which receives the pressurized fluid from the centrifugal compression mechanism, and which defines a flow passage alone or together with a part of the shell, wherein the flow passage is configured such that the pressurized fluid from the centrifugal compression mechanism passes through and cools the motor assembly.