Detuning Ring Structure for Vertical Pump Resonance Control
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Solution Overview
Problem
Vertical pump assemblies experience structural resonance conditions due to low stiffness, leading to amplified vibrations that breach compliance standards and cause equipment failure, particularly in variable frequency drives, with existing mitigation strategies being costly, requiring maintenance, or insufficient.
Innovation Solution
A detuning ring with a grooved structure is arranged between the drive unit and hydraulic unit, altering the natural frequencies of the pump assembly to reduce resonance, using a configuration that minimizes material and space while maintaining structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the pump assembly uses a low stiffness structure to minimize material and space, then the structural natural frequencies are at or near the excitation frequencies, but this leads to structural resonance conditions and amplified vibrations that breach compliance standards
Solution Approach 1:
The patent changes the physical parameters of the structure by adding a detuning mass to the driver stand, which alters the structural natural frequencies to move them away from excitation frequencies, thereby eliminating resonance conditions while maintaining the low-stiffness design
2Reliability
If detuning masses are added to the driver stand to shift natural frequencies, then resonance conditions are avoided, but the structural complexity and manufacturing cost increase
Solution Approach 1:
The driver stand is designed to serve multiple functions: it provides structural support for the drive unit, accommodates additional components, enables optimal discharge-head design, and acts as the mounting location for detuning masses, thereby eliminating the need for separate detuning devices
Solution Approach 2:
The detuning function is merged with the existing driver stand structure by utilizing its mass and structural characteristics, rather than adding separate detuning components, thereby reducing overall device complexity
3Strength
If welding stiffening ribs is used to increase system stiffness and detune resonance, then natural frequencies increase, but this results in considerable additional cost and prolonged lead-time
Solution Approach 1:
Instead of changing the structural stiffness through welding operations, the patent changes the mass distribution parameters by adding detuning masses to the driver stand, which shifts natural frequencies through mass addition rather than stiffness modification, avoiding costly welding operations
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 detuning ring effectively reduces resonance-induced vibrations, enhancing reliability and extending the lifetime of vertical pump assemblies with minimal cost and maintenance, suitable for both new and retrofitted equipment.
Implementation Method 1
vertical pumps typically exhibit relatively low stiffness structures, resulting in their lowest structural natural frequencies at or near the relevant excitation frequencies, which can potentially lead to structural resonance conditions and correspondingly amplified structural vibration levels
Data Source
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AI summary
A detuning ring is proposed for detuning a structural resonance in a pump assembly, wherein the pump assembly comprises a drive unit and a hydraulic unit, wherein the detuning ring is configured for being arranged between the drive unit and the hydraulic unit, wherein the detuning ring is further configured for being fixed relative to the drive unit or the hydraulic unit, wherein the detuning ring comprises a first axial face and a second axial face. The first axial face is configured with a plurality of first lands, wherein each first land extends in radial direction and comprises a planar first top face, wherein a plurality of first grooves is provided, wherein each first groove is delimited by two adjacent first lands and the first axial face, while the second axial face is configured with a plurality of second lands, wherein each second land extends in radial direction and comprises a planar second top face, wherein a plurality of second grooves is provided, wherein each second groove is delimited by two adjacent second lands and the second axial face. Further, the invention relates to a vertical pump assembly comprising a drive unit, a hydraulic unit with at least one impeller for rotating about an axial direction, a pump shaft connecting the drive unit with the at least one impeller, and a detuning device, wherein the detuning device is fixedly connected to the vertical pump assembly and the detuning device comprises a detuning ring arranged to surround a shaft. The invention additionally proposes a method for shifting a natural frequency of a vertical pump assembly comprising the step of arranging a detuning ring between the drive unit and the hydraulic unit.