Spindle Compressor Rotor Profile and Cooling for Leakage Reduction
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Solution Overview
Problem
Current dry-running 2-shaft rotary displacement compressors face limitations in efficiency and compression capacity due to high internal leakages between working chambers, which need to be improved for applications in vacuum and overpressure.
Innovation Solution
The design involves a 2-tooth and 3-tooth spindle rotor pair with a high wrap angle, cycloid-shaped profile contours, and fluid cooling, where the 2-tooth rotor has a convex profile above the gear pitch circle and the 3-tooth rotor has a concave profile below, with optimized tip circle radii and head profile pitch angles to achieve higher peripheral speeds and internal compression ratios, and a common cooling circuit for both rotors and the compressor housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wrap angle of the spindle rotors is increased to improve compression capacity, then the compression capacity increases, but the device complexity increases
Solution Approach 1:
The rotor design is segmented into distinct functional zones: a cylindrical inlet area with constant diameter for gas intake, and a conical compression area with varying diameter for compression. This segmentation allows the rotor to optimize performance in each zone independently while managing complexity through modular design.
Solution Approach 2:
The invention transitions from a 2D profile view to a 3D conical structure by varying the rotor diameter along the axial direction. This dimensional change enables the wrap angle to exceed 360 degrees while maintaining manageable complexity through systematic geometric progression.
2Productivity
If the peripheral speed of the spindle rotors is increased to improve efficiency, then the efficiency increases, but the temperature rise increases
Solution Approach 1:
A coolant is introduced as an intermediary substance to transfer heat away from the rotor. The coolant flows through channels in the rotor, absorbing compression heat and maintaining acceptable temperature levels while allowing high peripheral speeds to be sustained.
Solution Approach 2:
The coolant utilizes phase transition (evaporation/condensation) as a heat transfer mechanism to efficiently remove compression heat from the rotor, enabling high-speed operation without excessive temperature rise.
3Loss of energy
If the internal compression ratio is increased to minimize internal leakages, then the efficiency increases, but the manufacturing precision requirements increase
Solution Approach 1:
The invention systematically varies geometric parameters along the rotor length, including diameter, wrap angle, and profile shape. These controlled parameter changes optimize the internal compression ratio while maintaining manufacturability through systematic design rather than arbitrary precision requirements.
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 configuration enhances the compression capacity and efficiency by minimizing internal leakages and heat dissipation, allowing for higher pressure differences to be handled effectively while maintaining robustness and reliability.
Implementation Method 1
the heat conduction in the material and the heat-dissipating coolant-touched inner rotor cooling cone surfaces
Implementation Method 2
the heat-absorbing gas-side surfaces, the heat conduction in the material and the heat-dissipating coolant-touched inner rotor cooling cone surfaces, which results in an average rotor temperature
Data Source
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AI summary
The spindle rotor pair of the spindle compressor has a 2-toothed spindle rotor (2) and a 3-toothed spindle rotor (3) which engages without contact in terms of teething. The wrap-around angle with respect to the 2-toothed spindle rotor is at least 800°. A range of at least 30 m/sec is reached as the medium circumferential speed of the rotor head. Both of the rotors of the spindles of have, in the end section, circular sections (36.K and 36.F as well as 37.K and 37.F) and cycloidal profile contour edges (38 and 39) which in the case of the 2-toothed spindle rotor (2) are mainly configured above the toothing pitch circle (6) thereof and are of convex configuration, and in the case of the 3-toothed spindle rotor (3) are mainly embodied below the toothing pitch circle (7) thereof and in a concave, that is to say hollow, fashion. The end sections of each spindle rotor are preferably of symmetrical configuration, with the result that in each end section the centroid of the profile comes to rest on the respective centre of rotation of the rotor (M.2 or M.3).