Complex Screw Rotors With Circular Transitions for Radial Leakage
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Solution Overview
Problem
Existing rotary screw compressors face inefficiencies due to fixed rotor profiles and diameters, leading to increased leakage and reduced performance.
Innovation Solution
Implementing rotors with variable profiles and helical configurations, including right-hand and left-hand grooves/lobes with varying helices and diameters, transitioning to circular cross sections, and using scaled rack curves to design non-constant outer diameters and helical leads for enhanced meshing and compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed rotor profiles and diameters are used, then manufacturing is simple, but radial leakage increases and compression efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning from fixed rotor profiles to variable profiles where the outer diameter and helical configuration change along the axial length. The rotor includes a first section with a first outer diameter and a second section with a second outer diameter, where the second diameter differs from the first, creating a dynamic geometry that reduces radial leakage while maintaining manufacturability through systematic variable design
Solution Approach 2:
The patent implements parameter changes by varying multiple geometric parameters along the rotor length, including outer diameter, helix angle, and profile shape. The variable helical configuration and changing diameters are defined through rack curve scaling, allowing continuous parameter adjustment that reduces leakage paths and improves compression efficiency without excessive manufacturing complexity
2Device complexity
If fixed rotor profiles are used, then device complexity is low, but compression efficiency and pressure ratios are reduced
Solution Approach 1:
The patent applies segmentation by dividing the rotor into distinct sections along its axial length, with each section having different geometric parameters. The rotor includes a first section with specific outer diameter and helical configuration, and a second section with different parameters, allowing optimized compression in each zone while managing overall complexity through modular design
Solution Approach 2:
The patent introduces another dimension by adding axial variation to the rotor geometry, transitioning from two-dimensional fixed profiles to three-dimensional variable profiles. The rack curve scaling method enables continuous variation of outer diameter and helix angle along the axial direction, creating enhanced meshing and compression efficiency through added geometric freedom
3Reliability
If variable profiles and helical configurations are implemented, then sealing and compression efficiency improve, but manufacturing complexity increases
Solution Approach 1:
The patent uses parameter changes systematically through rack curve scaling to define variable profiles. By adjusting scaling factors and rack curve parameters, the outer diameter and helical configuration are continuously varied to optimize sealing performance. This systematic approach manages design complexity through mathematical relationships rather than arbitrary geometric variations
Data Source
AI summary
A compressor design includes a male rotor (10) having one or more helical lobes (12) and a female rotor (14) having one or more helical grooves (16). The male rotor is mounted on a first shaft and the female rotor is mounted on a second shaft. The male rotor is positioned in a first section of a chamber and the female rotor is positioned in a second section of the chamber. Fluid enters the chamber at an inlet, and when the rotors are driven, the lobes of the male rotor fit into the grooves of the female rotor, causing compression and movement of the fluid towards an outlet or discharge end where the compressed fluid is discharged. The configuration of the lobe and groove helix, the lobe and groove profile, and the outer diameter of the rotors can be varied in different combinations to form different rotors.