Cooled Dry Vacuum Screw Pump Intermediate Air Injection
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Solution Overview
Problem
Rotary screw positive displacement machines used as compressors face heating issues due to air compression, requiring cooling methods that are not always effective and often involve lubrication, which is not desirable for mobile and lightweight applications.
Innovation Solution
The introduction of additional intake air at an intermediate location between the inlet and outlet of the machine, optimized rotor configurations such as a 3/6 lobe configuration, and the use of a cycloid or parabolic shape for the rotor flanks to enhance gas flow and reduce thermal expansion, allowing for lower operating temperatures without lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rotary screw positive displacement machine is used as a compressor, then air compression function is achieved, but operating temperature increases excessively
Solution Approach 1:
The compression process is segmented into multiple stages with an intermediate cooling section. Fresh air is introduced at this intermediate section to cool the compressed air without requiring external cooling systems, thereby reducing operating temperature while maintaining compression function.
Solution Approach 2:
Fresh air acts as an intermediary cooling medium introduced at the intermediate section. This intermediate air injection cools the compressed air through heat exchange, reducing the operating temperature of the machine while the compression process continues.
2Temperature
If cooling methods are applied to reduce operating temperature, then temperature control is improved, but lubrication is required which increases device complexity and weight
Solution Approach 1:
The machine cools itself by utilizing the fresh air introduced at the intermediate section. This self-cooling mechanism eliminates the need for external lubrication systems and complex cooling apparatus, reducing device complexity while maintaining effective temperature control.
Solution Approach 2:
The introduction of fresh air changes the thermal parameters of the compressed air by lowering its temperature. This parameter change allows the machine to operate without lubrication, as the reduced temperature prevents excessive wear and heat generation that would otherwise require lubrication systems.
3Temperature
If additional intake air is introduced at intermediate location, then operating temperature decreases, but machine structure becomes more complex
Solution Approach 1:
The intermediate section serves multiple functions: it is both part of the compression chamber and the air injection point. This multi-functionality allows temperature reduction through air injection without requiring separate cooling structures, thereby minimizing the increase in device complexity.
4Productivity
If rotor configurations are optimized for gas flow, then compression efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The rotor configurations are optimized with specific local geometries (cycloid or parabolic shapes) at critical areas to enhance gas flow and compression efficiency. By focusing precision requirements on specific local regions rather than the entire rotor surface, manufacturing precision is managed more effectively while maintaining high compression efficiency.
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 approach reduces operating temperatures, maintains tight tolerances, and enables efficient vacuum generation and compressed air production while minimizing power utilization and weight, achieving temperatures below 225°C and maintaining efficiency.
Implementation Method 1
The introduction of additional intake air at an intermediate location between the inlet and outlet of the machine... reduces operating temperatures, maintains tight tolerances... achieving temperatures below 225°C
Implementation Method 2
Rotary screw positive displacement machines... serve as a vacuum pump... can also be used as compressors
Data Source
AI summary
The present invention relates to rotary screw positive displacement machines used as a vacuum pump wherein additional intake air is provided allowing cooling to the invention which permits extended operation at extreme vacuum pressure. The rotary screw nature of the vacuum pump allows operation without additional lubrication with the additional intake air ensuring that thermal expansion will not disrupt the tight tolerances of the invention. The invention allows simultaneous operation as a vacuum pump and air compressor.