Phase Control for Tumbler Screening Machines to Limit Structural Vibration
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Solution Overview
Problem
Multiple tumbler screening machines operating on the same support cause superposed oscillations that can lead to significant damage to buildings, as the amplitude of these oscillations can exceed safe limits, especially when machines are not synchronized and operate at resonant frequencies, resulting in increased structural loading and potential cracks.
Innovation Solution
A method to control the phase of oscillations between machines by adjusting their movement frequencies to ensure that the amplitude of oscillations on structural parts remains below a predefined maximum, using phase control and oscillation-damped arrangements to minimize transmission of vibrations to the building, with sensors monitoring and adjusting frequencies to maintain optimal phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple machines are operated simultaneously on the same support, then productivity is improved, but the amplitude of superposed oscillations increases causing structural damage
Solution Approach 1:
The patent applies periodic action by operating multiple machines with synchronized periodic movements at the same frequency but with controlled phase differences. The machines execute periodic tumbling movements where the phase of oscillation is adjusted so that when one machine is at the peak of its oscillation cycle, another is at a different phase position, causing the oscillations to cancel each other out rather than superpose constructively
Solution Approach 2:
The patent employs parameter changes by modifying the phase parameter of machine operation. Specifically, the phase difference between machines is adjusted to optimal values (such as 180 degrees or other calculated phase differences) to achieve destructive interference of oscillations. This parameter adjustment transforms the harmful superposed oscillations into minimized vibrations, allowing multiple machines to operate simultaneously without exceeding structural load limits
2Productivity
If machines operate at resonant frequencies, then processing efficiency is improved, but structural damage risk increases due to amplified oscillations
Solution Approach 1:
The patent converts the harmful effect of resonant oscillations into a beneficial outcome by using the same resonant frequency principle in reverse. Instead of avoiding resonant frequencies entirely, the patent operates machines at frequencies that would individually cause resonance but uses phase control to create destructive interference. The harmful resonant oscillations of individual machines are transformed into a beneficial cancellation effect, where the combined oscillation amplitude remains below structural damage thresholds while maintaining processing efficiency
3Reliability
If phase control is implemented to reduce oscillations, then structural safety is improved, but system complexity increases due to coordination requirements
Solution Approach 1:
The patent implements feedback control by continuously monitoring the oscillation state of machines and automatically adjusting the phase differences to maintain optimal cancellation conditions. Sensors detect vibration levels and phase positions, and this information is fed back to the control system which adjusts motor speeds or timing to maintain the desired phase relationships. This closed-loop feedback mechanism ensures structural safety is maintained while automating the complex coordination requirements, reducing the burden on operators
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 approach effectively reduces the amplitude of superposed oscillations, preventing damage by ensuring that the oscillations of machines are anti-phase, thereby minimizing the overall impact on the building structure, even when multiple machines are operating simultaneously.
Implementation Method 1
If multiple machines are arranged in a building or in part of the building, the oscillations generated are superposed. The maximum amplitude of the superposed oscillation here is equal to the sum of the maximum amplitude of the individual oscillations.
Implementation Method 2
the phase of an oscillation of one machine in relation to the phase of an oscillation of a further machine is controlled by shifting the phases with respect to one another such that the amplitude of an oscillation of a structural part remains below a predefined maximum value
Data Source
AI summary
A method is described for operating machines (10) having moving parts and arranged jointly on a support (32), said parts being moved periodically with substantially the same frequency, and wherein the phase of an oscillation of one machine (10) in relation to the phase of an oscillation of a further machine (10) is controlled by shifting the phases with respect to one another such that the amplitude of an oscillation of a structural part, for example of the support (32), remains below a predefined maximum value.