Screw compressor economizer plenum for pulsation reduction
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Solution Overview
Problem
Positive displacement compressors, such as screw compressors, experience pulsation propagation from the economizer port, leading to annoying sound and unwanted vibration due to the opening and closing of compression pockets, which current solutions like mufflers and sound damping materials only partially address.
Innovation Solution
A screw compressor design featuring a chamber between the economizer port and the external port with a volume of at least 0.8 liters, where the chamber has a protuberant portion with a minimum cross-sectional area at least twice that of the external port, effectively dissipating pulsation through increased volume and area ratios, and is formed by a casting core in the compressor housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a chamber with large volume and protuberant portion is added between economizer port and external port, then pulsation transmission loss is improved (at least 3dB rms), but device complexity and housing space requirements worsen
Solution Approach 1:
The chamber is nested within the existing compressor housing structure, utilizing the available internal space between the economizer port and external port. The protuberant portion is integrated into the housing rather than being an external addition, effectively nesting the pulsation-dampening volume within the existing device boundaries.
Solution Approach 2:
The chamber introduces a volumetric dimension to the economizer flowpath, transitioning from a simple linear passage to a three-dimensional space with varying cross-sectional areas. The protuberant portion creates a localized volume expansion that provides pulsation attenuation without significantly increasing the overall compressor footprint.
2Object-affected harmful factors
If chamber volume is increased to at least 30% of displacement per revolution, then pulsation dissipation is improved, but housing volume requirements worsen
Solution Approach 1:
The chamber provides localized volume expansion at the critical location between the economizer port and external port, where pulsation attenuation is most needed. The protuberant portion creates a focused volume increase rather than uniformly expanding the entire housing, concentrating the pulsation-dampening function in a specific region.
Solution Approach 2:
The chamber volume is designed as a specific parameter (at least 30% of displacement per revolution) that can be adjusted based on compressor size and application requirements. This parameter-based design allows optimization of pulsation reduction while adapting to different compressor configurations.
3Object-affected harmful factors
If protuberant portion with minimum cross-sectional area at least twice external port area is used, then pulsation transmission loss is improved, but manufacturing complexity worsens
Solution Approach 1:
The protuberant portion acts as an intermediary structure between the economizer port and external port, providing a transition zone that manages pulsation flow. This intermediate volume with controlled cross-sectional area serves as a buffer that simplifies the overall flowpath design while achieving pulsation reduction.
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 design provides significant pulsation transmission loss of at least 3dB rms over a majority of the male rotor speed range, expanding the compressor's operational envelope and reducing vibration and noise effectively.
Implementation Method 1
the chamber has a volume of at least 0.8 liter; the volume is at least 30% of a displacement per revolution of the male rotor; the chamber has a protuberant portion; and at a first location the protuberant portion has a minimum cross-sectional area of at least twice an area of the external port
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A compressor (22) has a male rotor (52), a female rotor (54), and a housing (50). The housing has a first bore (114) and a second bore (116) respectively accommodating portions of the male rotor and the female rotor. The housing has an inlet (26), an outlet (28), an economizer port (150) along at least one of the first bore and the second bore, and an external port (46) communicating with the economizer port. The housing has a chamber (152) between the economizer port and the external port having a volume of at least 0.8 liter.