Passive Axial Balancing System for Rotating Machines
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Solution Overview
Problem
Rotating machines, such as pumps and turbines, face significant axial forces due to gravity and fluid counter-reaction, leading to excessive stress on bearings, which can result in reduced service life, especially when active axial balancing systems are insufficient.
Innovation Solution
The integration of a passive axial balancing system utilizing a secondary flow of liquid, which provides a constant axial recovery force independent of the shaft's movement, complementing the active axial balancing system to enhance overall axial recovery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active axial balancing system is used to compensate axial forces, then the axial recovery force can be regulated according to shaft movement, but the intensity of the axial recovery force may become insufficient in certain situations
Solution Approach 1:
The axial balancing system is divided into two independent parts: an active axial balancing system that provides regulated recovery force based on shaft movement, and a passive axial balancing system that provides additional constant recovery force. This segmentation allows each subsystem to perform its specific function without interfering with the other, ensuring reliable axial support even when the active system alone is insufficient.
Solution Approach 2:
The patent combines the active and passive axial balancing systems into a single integrated axial support system. The passive system uses a secondary liquid flow from the main flow to generate constant axial recovery force through pressure differential across a restriction, while the active system provides movement-dependent regulation. Together, they provide comprehensive axial balancing capability.
2Force
If a passive axial balancing system is added to increase axial recovery force, then the overall axial recovery capacity is improved, but the machine structure becomes more complex
Solution Approach 1:
The secondary liquid flow circuit serves multiple functions: it provides cooling for the motor and bearings, and simultaneously powers the passive axial balancing system through the restriction element. This multi-functionality allows the passive balancing system to be integrated without requiring a separate dedicated flow circuit, thereby reducing the expected increase in structural complexity.
Solution Approach 2:
The passive axial balancing system is self-powered by extracting a portion of the main liquid flow that passes through a restriction element. The pressure differential created by this restriction automatically generates the axial recovery force without requiring external power sources, control systems, or additional energy input, making the system self-sufficient.
3Strength
If the axial recovery force is increased to counteract gravity and fluid forces, then bearing stress is reduced, but the system requires additional components and circuitry
Solution Approach 1:
The passive axial balancing system utilizes hydraulic principles by using liquid pressure differential across a restriction element to generate axial recovery force. The secondary liquid flow creates pressure difference that acts on a piston or diaphragm connected to the shaft, providing bearing support through fluid pressure rather than mechanical components.
Solution Approach 2:
The restriction element acts as an intermediary component that converts the kinetic energy of the secondary liquid flow into pressure differential, which then generates the axial recovery force. This intermediary mechanism allows the system to increase bearing load capacity without directly adding complex mechanical force-generating 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
The passive axial balancing system increases the overall axial recovery force, reducing bearing stress and extending service life by providing a consistent counteracting force to gravity and fluid-induced forces, while also simplifying the machine's structure by using the same liquid for cooling and balancing.
Implementation Method 1
The passive axial balancing system is powered by a circuit of a secondary flow of liquid taken from the main flow of liquid... the secondary flow of liquid circulating in the circuit during operation of the machine, advantageously supplies the passive axial balancing system
Implementation Method 2
a circuit for a secondary flow of liquid taken from the main flow of liquid... an annular passage between the shaft and the casing, through which the secondary flow of liquid is intended to flow
Implementation Method 3
the annular passage axially delimiting an upstream fluidic chamber from a downstream fluidic chamber, such that the pressure in the upstream fluid chamber is greater than the pressure in the downstream fluidic chamber. The annular passage is defined radially between the outer periphery of the disk and an inner surface of the housing
Data Source
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AI summary
The invention relates to a rotating machine intended to be traversed by a main flow of liquid, comprising: - a shaft (20) mounted to rotate relative to a housing of the rotating machine, - an active axial balancing system capable of exerting a first axial balancing force on the shaft. The invention is characterized in that the rotating machine further comprises a circuit for a secondary liquid flow (F2) taken from the main liquid flow, and a passive axial balancing system (42) capable of exerting a second axial balancing force on the shaft, said passive axial balancing system being supplied by the secondary liquid flow circuit (F2).