Centrifugal Pump Thrust Balancing via Fluid Chamber
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Solution Overview
Problem
Centrifugal pumps face significant axial thrust challenges due to high pressure forces generated during operation, which can lead to misalignment and increased wear, particularly in applications like reverse osmosis systems, where axial forces can exceed radial forces, causing instability and potential mechanical failure.
Innovation Solution
The implementation of a fluid-lubricated sleeve-bearing system with a thrust chamber, including a disc and seal ring, which communicates fluid from the impeller chamber through a bearing clearance to generate a counter-acting force, neutralizing axial thrust by increasing pressure in the thrust chamber and balancing forces, thereby reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bearing system is used to support the shaft, then radial location is provided, but axial thrust forces cause misalignment and increased wear
Solution Approach 1:
The patent introduces a thrust chamber with a counter-acting force generation mechanism that creates a force equal and opposite to the axial thrust. The thrust chamber receives fluid from the impeller chamber through bearing clearance and generates a counter-thrust force that balances the axial load, preventing shaft misalignment and reducing bearing wear.
Solution Approach 2:
The thrust chamber acts as an intermediary element between the impeller chamber and the bearing system. It mediates the axial thrust forces by providing a controlled fluid pathway that generates a balancing force, thereby protecting the bearing system from direct axial loads while maintaining shaft alignment.
2Strength
If axial thrust forces are not balanced, then mechanical stress and wear increase, but adding thrust balancing mechanisms increases device complexity
Solution Approach 1:
The patent merges the thrust balancing function with the existing bearing chamber structure. The thrust chamber is integrated into the bearing assembly, utilizing the same spatial envelope and fluid pathways. This consolidation allows thrust balancing to be achieved without adding separate external components, thereby reducing overall device complexity while maintaining stress resistance.
Solution Approach 2:
The bearing chamber is designed to serve multiple functions: supporting the shaft radially, managing axial thrust forces through the thrust chamber, and providing fluid lubrication. This multi-functionality eliminates the need for separate dedicated thrust balancing components, reducing device complexity while enhancing mechanical strength.
3Force
If fluid pressure in the thrust chamber is increased to balance axial thrust, then axial force balancing is achieved, but mechanical stress on components increases
Solution Approach 1:
The thrust chamber utilizes the fluid pressure already present in the impeller chamber to generate the counter-thrust force. The system is self-regulating, where the fluid flow naturally provides the balancing force without requiring external pressure control mechanisms. This self-service approach balances axial forces while minimizing additional stress on components.
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 solution effectively balances axial thrust forces, reducing mechanical stress and wear, enhancing the stability and longevity of centrifugal pumps, particularly in high-pressure applications like reverse osmosis systems, by neutralizing the axial thrust and maintaining efficient operation.
Implementation Method 1
The thrust chamber is in fluid communication with the impeller chamber through the bearing clearance so that an axial thrust in an inboard direction is generated by the thrust chamber
Implementation Method 2
communicating fluid from the impeller chamber through a bearing clearance between the bearing and the shaft to a thrust chamber at the inboard end of the bearing and generating an inboard axial force in response to communicating fluid
Implementation Method 3
A seal ring is disposed between the disc and the inboard-bearing surface
Implementation Method 4
The bearing and the shaft have a bearing clearance therebetween
Data Source
AI summary
A centrifugal pump includes a casing having an impeller chamber, an inlet, an outlet, and a bearing chamber. A shaft disposed within the casing has an impeller end and a motor end. The impeller is coupled to the impeller end of the shaft and is disposed within the impeller chamber. A bearing is disposed within the bearing portion. The bearing has an inboard end with an inboard-bearing surface and an outboard end with an outboard-bearing surface. The bearing and the shaft have a bearing clearance therebetween. A disc is coupled to the shaft on the impeller end which is spaced apart from the inboard-bearing surface. A seal ring is disposed between the disc and the inboard-bearing surface. The shaft, the seal ring, the disc, and the inboard-bearing surface define a thrust chamber therebetween. The thrust chamber is in fluid communication with the impeller chamber through the bearing clearance so that an axial thrust in an inboard direction is generated by the thrust chamber.