Hermetic Compressor Housing Design to Shift Noise Above 4200 Hz
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Solution Overview
Problem
Current hermetic compressors for positive displacement in refrigeration systems generate noise predominantly in a frequency range well perceived by human hearing due to their natural frequencies, and existing noise reduction methods either compromise refrigeration capacity or increase production costs.
Innovation Solution
Designing a hermetic compressor with an airtight housing having natural frequencies above 4200 Hz, achieved through miniaturization and optimization of the compressor's internal components, and increasing the electric motor's maximum angular speed to 5000 rpm to maintain refrigeration capacity while reducing noise perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the natural frequencies of the airtight housing are increased above 4200 Hz through miniaturization and optimization, then noise radiation in the human-perceived frequency range is reduced, but the refrigeration capacity decreases
Solution Approach 1:
The patent changes the natural frequency parameter of the airtight housing from the conventional range (around 3200 Hz) to above 4200 Hz through miniaturization and optimization of the housing structure. This parameter change shifts the resonance frequency out of the human-perceived noise range, reducing noise radiation while the patent compensates for refrigeration capacity loss through increased motor speed
Solution Approach 2:
The patent applies dynamics by increasing the maximum angular speed of the electric motor from conventional limits (4500 rpm) to 5000 rpm. This dynamic adjustment compensates for the reduced refrigeration capacity caused by housing miniaturization, maintaining productivity while enabling the noise reduction benefits of the optimized housing
2Productivity
If the maximum angular speed of the electric motor is increased to 5000 rpm, then refrigeration capacity is maintained despite housing miniaturization, but noise generation from motor operation increases
Solution Approach 1:
The patent converts the potentially harmful effect of increased motor noise into a benefit by operating the motor at higher speed (5000 rpm). The increased motor speed compensates for the reduced refrigeration capacity from housing miniaturization. The overall system noise is reduced because the housing natural frequencies are shifted above 4200 Hz, placing the motor noise in a less perceived frequency range
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 solution effectively shifts noise perception to a less sensitive frequency range, reducing noise radiation by 3 phon and maintaining refrigeration capacity within acceptable domestic standards, with a net reduction of 3 phon in perceived noise.
Implementation Method 1
the vibrations generated within the compressor in the vapor compression process are transmitted to the housing and can be amplified according to the natural frequencies of vibration of the airtight housing
Implementation Method 2
the vibrations generated within the compressor in the vapor compression process are transmitted to the housing and can be amplified according to the natural frequencies of vibration of the airtight housing
Data Source
AI summary
The invention in question pertains to the technological field of refrigeration compressors.A hermetic compressor for positive displacement is disclosed whose airtight housing is specially altered so that its natural frequencies of vibration are distributed at frequencies above 4200 Hz and whose “capacitance density” is greater than 160 W/L.