Load-relieving Device Axial Thrust Compensation
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Solution Overview
Problem
Existing turbomachine axial thrust compensation methods, such as balancing discs, single piston, and double piston, face issues during start-up and shut-down where pressure differences have not yet built up, leading to potential contact between relief and counter-elements, resulting in rubbing and increased overall length due to separate housings and lubricants.
Innovation Solution
A device is integrated onto the counter-element within the turbomachine, featuring a force-generating element, such as a spring, and an axially displaceable element with a sliding bearing, preventing the relief element from rubbing against the counter-element by maintaining a controlled distance through hydraulic or magnetic forces, eliminating the need for additional housings and lubricants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring packs in a separate lifting device are used to prevent rubbing during start-up, then rubbing is prevented, but the overall length is extended and a separate housing is required
Solution Approach 1:
The lifting device is merged with the counter-element by integrating the spring pack directly onto the counter-element surface. The device comprises a spring pack and an axially displaceable element that is integrally formed with or directly mounted on the counter-element, eliminating the need for a separate lifting device housing and reducing overall length while maintaining rubbing prevention functionality.
Solution Approach 2:
The counter-element is given multiple functions: it serves both as the thrust-bearing surface and as the mounting base for the lifting device. The axially displaceable element integrates the lifting function with the counter-element structure, allowing one component to perform multiple roles and eliminate separate housings.
2Force
If a cardanic ring in a separate sealed room is used to absorb axial forces, then axial forces are absorbed, but additional overall length is created
Solution Approach 1:
The lifting device is merged with the counter-element structure. The spring pack and axially displaceable element are integrated onto the counter-element, combining the axial force absorption function with the existing counter-element geometry, thereby avoiding extension of the stationary housing.
3Force
If freely movable axial bearing and outer bearing ring with spring force are used to limit axial thrust, then axial thrust is limited, but overall length is extended and additional lubrication is required
Solution Approach 1:
The lifting device components (spring pack and axially displaceable element) are merged with the counter-element, reducing the number of separate bearing components. This integration simplifies the device structure while maintaining axial thrust limitation through the spring force mechanism.
Solution Approach 2:
The spring pack automatically generates the necessary lifting force during start-up and shut-down without requiring external lubrication systems. The device uses the inherent spring force and the pumped medium itself to prevent rubbing, eliminating the need for separate lubrication infrastructure.
4Length of moving object
If the device is arranged on the counter-element within the flow area, then no extension of shaft or housing is required, but the device must function in the medium flow
Solution Approach 1:
The axially displaceable element acts as an intermediary between the spring pack and the relief element. It is designed to be compatible with the medium flow, allowing the spring force to be transmitted while the element itself can withstand or be compatible with the pumped medium environment.
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 ensures reliable prevention of relief element contact with the counter-element during start-up and shut-down, maintaining the radial throttle gap geometry, reducing wear, and avoiding additional length and lubrication requirements, while achieving balanced forces and efficient operation.
Implementation Method 1
The device comprises a spring pack (14)
Implementation Method 2
The pressure difference acting between two sides of the balancing element results in a balancing force that opposes the axial thrust
Implementation Method 3
The relief force, which is just as great as the axial thrust
Implementation Method 4
A sliding bearing element (16) is preferably arranged on the axially displaceable element
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an arrangement for compensating the axial thrust of a fluid-flow machine. A load-relieving element (11) is non-rotatably connected to a shaft (1). A flow-restrictor gap (13) is formed by this element together with a counter-element (12) secured to the housing, said gap being formed between the load-relieving element (11) and the counter-element (12). The counter-element (12) is provided with a device for maintaining the distance between the load-relieving element (11) and the counter-element (12). The device comprises at least one force-generating element (14). Said force -generating element (14) generates a force that acts in opposition to the axial thrust.