Centrifugal Compressor Vertical Shaft Lubrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed small centrifugal compressors face cost challenges with high-speed oil-free bearings, and existing designs are complex, making it desirable to simplify the structure and introduce lubricated bearings for cost-effectiveness and compactness.
Innovation Solution
A vertically arranged centrifugal compressor design featuring a shell with a fluid inlet and outlet, a motor assembly with a stator and rotor, and a centrifugal compression mechanism, where the rotor shaft is supported by bearings and lubricated by an oil passage with radial perforations, allowing fluid to flow from the inlet through the motor assembly and into a guide passage for compression, with oil circulation for lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed oil-free bearings are used in small centrifugal compressors, then reliability is improved, but cost increases significantly
Solution Approach 1:
The patent replaces expensive high-speed oil-free bearings with conventional lubricated bearings that can be easily replaced. The bearing assembly is designed as a modular component that can be quickly changed during maintenance, making the cheaper bearing type economically viable despite shorter service life.
Solution Approach 2:
The patent introduces an oil lubrication system using hydraulic principles to lubricate the bearings. Oil is delivered through a lubrication hole in the rotor shaft to the bearing locations, providing effective lubrication that enables the use of conventional bearings instead of expensive oil-free alternatives.
2Ease of manufacture
If conventional lubricated bearings are used instead of oil-free bearings, then cost is reduced, but device complexity increases due to oil circuit requirements
Solution Approach 1:
The patent merges the oil lubrication system with the existing refrigerant circulation system. The oil circuit is integrated into the compressor housing and utilizes the same general fluid pathways, eliminating the need for separate complex lubrication infrastructure and reducing overall system complexity.
Solution Approach 2:
The lubrication system is designed to be self-regulating, where oil automatically circulates through the system based on pressure differentials and gravity. The oil tank, pump, and distribution channels are arranged to provide automatic lubrication without requiring complex control systems or external intervention.
3Volume of moving object
If the compressor is designed for compactness, then volume is reduced, but structural complexity increases
Solution Approach 1:
The patent employs nested positioning where the motor assembly is placed within the compressor housing, and the lubrication system components are integrated within existing structural spaces. The rotor shaft passes through the motor assembly to connect to the impeller, creating a compact nested arrangement that reduces overall volume without requiring complex external linkages.
Solution Approach 2:
The patent utilizes vertical stacking of components along the axial direction to achieve compactness. The motor, compressor elements, and lubrication components are arranged in layers along the vertical axis, effectively using the third dimension to pack components densely without increasing the horizontal footprint, thereby maintaining simplicity in the planar layout.
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 design reduces axial stress on bearings, enables a compact and cost-effective compressor suitable for low-power applications by using lubricated bearings and an efficient fluid flow path, while maintaining compressor performance.
Implementation Method 1
a centrifugal compression mechanism, an impeller of which is connected with the rotor shaft so as to be driven by the motor assembly
Implementation Method 2
the rotor shaft defines an axial or oblique oil passage therein, and has radial perforations at positions corresponding to the first bearing and the second bearing
Data Source
Figure 1
Figure 2
AI summary
A centrifugal compressor and a refrigerating device. The compressor includes: a shell, which has a fluid inlet at a first position of the shell, and a fluid outlet at a second position of the shell, a motor assembly, which is arranged in the shell and includes a stator and a rotor, the rotor including a vertically arranged rotor shaft, and the rotor shaft including a lower end and an upper end; a centrifugal compression mechanism, an impeller of which is connected with the rotor shaft so as to be driven by the motor assembly; and a guide member, which is located above the centrifugal compression mechanism, and which defines a flow passage alone or together with a top part of the shell.