Vacuum Pump Stator Heating and Insulation Design
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Solution Overview
Problem
Vacuum pumps used in semiconductor manufacturing face issues with gas solidification due to temperature drops, leading to compromised compression and exhaust performance, and excessive heat escape from insulating spacers, which can damage electrical components and rotor/stator blades.
Innovation Solution
A vacuum pump design featuring a heat-insulating spacer with a flange portion and a cartridge heater, where the distance between the rotor and stator at the inlet port is greater than or equal to the distance at the outlet port, and the spacer has a lower linear expansion coefficient than the stator, preventing gas solidification and heat escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the stator is heated to prevent gas solidification, then the gas can be transferred without solidifying, but the heat escapes from the insulating spacer to the surrounding, causing damage to electrical components and rotor/stator blades
Solution Approach 1:
A heat insulating spacer is introduced as an intermediary component between the stator and the surrounding structure. This spacer has low thermal conductivity and acts as a thermal barrier, preventing heat from escaping to electrical components and other sensitive parts while allowing the stator to be heated effectively to prevent gas solidification.
Solution Approach 2:
The harmful heat transfer path is extracted and isolated by removing direct thermal contact between the stator and surrounding components. The heat insulating spacer creates thermal isolation, separating the heating zone from sensitive areas, thereby preventing heat-induced damage to electrical components and blades.
2Productivity
If the distance between rotor and stator is reduced to improve compression performance, then the gas flow channel is narrowed for better compression, but the rotor and stator blades may collide due to thermal expansion or deformation
Solution Approach 1:
The gap between the rotor and stator is optimized by adjusting geometric parameters to achieve the desired compression performance. Simultaneously, material selection and thermal design are modified to control thermal expansion, ensuring that the gap remains sufficient to prevent blade collision while maintaining effective compression.
Solution Approach 2:
The heat insulating spacer is installed beforehand to prevent excessive heat transfer that could cause thermal expansion and blade collision. This preventive measure ensures that the rotor-stator gap remains stable under operating conditions, avoiding blade contact while maintaining 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 configuration maintains proper pump operation by preventing gas solidification and reducing heat transfer to electrical components, ensuring the stator is heated uniformly while minimizing heat loss and blade damage.
Implementation Method 1
a heating means for heating the stator
Implementation Method 2
a heat insulating means for insulating the stator from stator components other than the stator
Implementation Method 3
the spacer is a member having a linear expansion coefficient lower than a linear expansion coefficient of the stator
Data Source
Figure 1
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Figure 3
AI summary
Provided is a vacuum pump that prevents the solidification of gas while being operated properly. The vacuum pump includes a rotor that is supported rotatably on a base, a stator that has a thread groove portion, and a heating structure that heats the stator. The heating structure has a spacer that insulates the stator from stator components other than the stator, and a cartridge heater that heats the stator. The distance between a rotor cylindrical portion and the stator at the inlet port side is set to be equal to or greater than the distance between the rotor cylindrical portion and the stator at the outlet port side.