Pump Waveform Chopping Control to Reduce Beverage Machine Noise
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Solution Overview
Problem
Beverage and foodstuff preparation machines experience significant noise due to pump vibrations, with existing noise reduction methods like voltage control during start-up still producing undesirable noise levels.
Innovation Solution
A control system that adjusts the waveform of electrical energy supplied to the pump during start-up by chopping a portion of the waveform in a non-linear manner, with a greater rate change towards the end of the start-up phase, to reduce noise and ensure smooth fluid line filling without detrimental pressure increase for product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voltage is ramped up linearly during start-up phase, then the pump reaches nominal operating voltage, but undesirable noise remains
Solution Approach 1:
The patent applies periodic chopping of the voltage waveform during the start-up phase, where portions of the waveform are periodically removed rather than applying continuous linear ramping. This periodic action reduces the average power delivered to the pump motor during start-up, thereby reducing vibrations and noise while still allowing the pump to eventually reach nominal operating voltage.
Solution Approach 2:
The patent changes the parameter of voltage application from continuous linear ramping to discontinuous chopped waveform. By modifying how voltage is applied (chopping portions of the waveform), the power delivery characteristics change, reducing noise during start-up while maintaining the ability to reach full operating power.
2Speed
If high power is applied to empty fluid line, then pump starts quickly, but noise increases substantially
Solution Approach 1:
By periodically chopping the voltage waveform during start-up, the patent reduces average power delivery to the pump motor. This prevents high instantaneous power from being applied to the empty fluid line, reducing noise while still allowing the pump to accelerate to operating speed through the controlled start-up sequence.
Solution Approach 2:
The patent applies preliminary low-power operation during the start-up phase before full power is reached. By using chopped waveforms initially, the system prepares the pump for operation at reduced noise levels, then transitions to full power only after the pump is running and fluid flow is established.
3Object-generated harmful factors
If pump is mounted on elastic member to isolate vibrations, then noise transmission is reduced, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical vibration isolation system (elastic mounting members) with an electrical control solution (waveform chopping). Instead of mechanically isolating the pump vibrations through elastic mounts, the invention controls the electrical power input to reduce vibrations at their source, thereby achieving noise reduction without adding mechanical complexity.
4Manufacturing precision
If non-linear chopping is applied to reduce noise, then product quality is maintained, but control complexity increases
Solution Approach 1:
The patent implements dynamic control of the waveform chopping parameters during the start-up phase. The chopping duty cycle and pattern are varied over time in a non-linear fashion to optimize noise reduction while maintaining product quality. This dynamic approach allows the control system to adapt to changing pump operating conditions without requiring complex hardware modifications.
Data Source
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AI summary
A beverage or foodstuff preparation machine (4) comprising: a component processing unit (14) operable to prepare a beverage or foodstuff from a beverage or foodstuff component, said component processing unit comprising a pump (22) arranged to deliver fluid to said component; a control system (16) configured to control a waveform of electrical energy supplied to the pump (22), wherein said control comprises during a start-up phase chopping a portion of a period of a repeating unit of said waveform, whereby the portion chopped varies between a start and an end of the start-up phase in a non-linear manner with respect to time and with a greater rate change proximate said end than proximate said start.