Vacuum Pump Rotor Side Plate Pressure Equalization
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Solution Overview
Problem
Conventional vacuum pumps experience durability issues due to pressure differences causing the rotor and side plate to contact, leading to wear and degradation, especially when the side plate is made of low-rigidity materials like carbon.
Innovation Solution
Incorporating an intercommunication port between the side plate and the rotor's shaft hole to equalize pressure differences, combined with a seal member to prevent air from entering the space between the rotor and side plate, and a bearing portion for precise alignment of the rotating shaft, reducing contact and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the side plate is formed of low-rigidity material such as carbon, then the weight is reduced and sealing performance is improved, but the side plate sags due to pressure difference causing contact with the rotor
Solution Approach 1:
A pressure equalization hole is introduced as an intermediary element to connect the high-pressure and low-pressure spaces, allowing pressure equalization that prevents the side plate from sagging under pressure differential, thereby maintaining both the use of low-rigidity materials and preventing contact with the rotor
Solution Approach 2:
The pressure distribution parameter is changed by introducing the pressure equalization hole, transforming the pressure differential condition into an equalized pressure condition, which eliminates the sagging problem while maintaining the benefits of low-rigidity side plate materials
2Reliability
If the intercommunication port is made larger, then pressure equalization is improved, but air flow through the port increases reducing compressibility
Solution Approach 1:
Instead of fully opening the pressure equalization hole, a controlled partial opening is provided that is sufficient to equalize pressure between spaces but limited in size to minimize air flow that would reduce compressibility, achieving the optimal balance between pressure equalization and vacuum pump performance
3Reliability
If the intercommunication port is positioned away from the axial center, then pressure equalization is achieved, but compression and expansion performance is reduced
Solution Approach 1:
The pressure equalization hole is positioned at the axial center where the pressure potential is most representative of the overall pressure distribution, allowing effective pressure equalization while minimizing interference with the compression and expansion processes that occur during rotor rotation
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 effectively suppresses abrasion between the rotor and side plate, enhancing the vacuum pump's durability and maintaining performance by preventing pressure-induced contact and misalignment.
Implementation Method 1
the intercommunication port which confronts the shaft hole of the rotor and intercommunicates with the space between the side plate and the pump cover, and thus the pressure difference between the neighborhood of the shaft hole of the rotor and the space can be suppressed
Implementation Method 2
a seal member through which an exhaust passage from the cylinder chamber to the outside thereof and the space are isolated from each other may be disposed around the cylinder chamber between the casing body and the pump cover
Data Source
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AI summary
Durability of a vacuum pump is prevented from degrading by suppressing abrasion of a rotor and a side plate. The vacuum pump has a hollow cylinder chamber S having an opening at an end portion of a casing body, a rotor 27 which is rotationally driven in the cylinder chamber S, a side plate 26 for blocking the opening of the cylinder chamber S, and a pump cover 24 which is disposed at the opposite side to the rotor 27 so as to sandwich the side plate 26 between the pump cover 24 and the rotor 27, and the side plate 26 is provided with an intercommunication port 261 which confronts a shaft hole 27A of the rotor 27 and intercommunicates with a space 80 between the side plate 26 and the pump cover 24.