Oil-free Screw Compressor Atmosphere Communication Simplification
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Solution Overview
Problem
The oil-free screw compressor designs, such as those described in JP S61-144289 U, are complex and difficult to manufacture due to the need for multiple atmosphere communication portions in the casing, leading to increased distances between screw rotors and bearings, which can cause bending and reduce volumetric efficiency.
Innovation Solution
A simplified design where both communication portions of the first and second shaft seal devices communicate with a single atmosphere communication portion within the casing, reducing the distance between the screw rotor and the bearing and preventing bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate atmosphere communication portions are formed in the casing to communicate with the first and second shaft seal devices, then the shaft seals can prevent lubricating oil intrusion, but the device complexity increases and manufacturing becomes difficult
Solution Approach 1:
The patent combines two separate atmosphere communication portions into a single integrated atmosphere communication portion that serves both the first shaft seal device and the second shaft seal device. This merging reduces the number of components and simplifies the overall configuration while maintaining the function of preventing lubricating oil intrusion into the rotor chamber.
Solution Approach 2:
The single atmosphere communication portion is designed to perform multiple functions: it communicates atmosphere to the first shaft seal device and to the second shaft seal device simultaneously. This multi-functional design eliminates the need for separate communication portions for each shaft seal, thereby reducing device complexity.
2Reliability
If two separate atmosphere communication portions are formed in the casing, then shaft seal functionality is maintained, but the distance between screw rotor and bearing increases causing rotor bending
Solution Approach 1:
By merging the atmosphere communication paths into a single integrated portion, the patent enables the first and second shaft seal devices to be positioned closer to each other along the rotation center line. This reduced spacing consequently shortens the distance between the screw rotor and the bearing, preventing rotor bending while maintaining seal functionality.
3Length of moving object
If the communication portions of shaft seal devices are positioned close to each other, then the distance between screw rotor and bearing is short, but two separate atmosphere communication portions are required increasing manufacturing complexity
Solution Approach 1:
The patent resolves this contradiction by designing a single atmosphere communication portion that can serve multiple shaft seal devices positioned close together. This integrated design allows short spacing between components (improving ease of manufacture) while maintaining the necessary atmospheric communication functions for both shaft seals.
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 allows for easier manufacturing and prevents screw rotor bending, thereby enhancing the performance and efficiency of the oil-free screw compressor.
Implementation Method 1
an atmosphere communication portion connected to both of the first communication portion and the second communication portion on the inner peripheral face of the shaft accommodation space and communicating the first communication portion and the second communication portion with the atmosphere
Data Source
AI summary
An oil-free screw compressor has a screw rotor including a screw and a shaft, a bearing supporting the shaft, a first shaft seal device disposed between the screw and the bearing and including a first seal opposite to the shaft, and a first communication portion communicating the inner periphery face and the outer peripheral face of the first shaft seal device, a second shaft seal device disposed between the first shaft seal device and the bearing and including a second seal opposite to the shaft, and a second communication portion communicating an inner periphery face and the outer peripheral face of the second shaft seal device, and a casing including an atmosphere communication portion connected to both of the first communication portion and the second communication portion on the inner peripheral face of a shaft accommodation space.