Threaded Groove Spacer for Vacuum Pump Deposition Prevention
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Solution Overview
Problem
Vacuum pumps, such as turbo-molecular and threaded groove pumps, face issues with deposition of products at the outlet port due to thermal expansion and creep, leading to performance deterioration and potential breakdown, especially in semiconductor manufacturing applications, where existing heating methods are inefficient and increase the number of assembly steps and parts.
Innovation Solution
A vacuum pump configuration with a stator-side member, specifically a threaded groove spacer, having a coefficient of thermal conductivity lower than the tubular rotating member, made from stainless steel with a lower conductivity than aluminum or aluminum alloys, which prevents heat conduction and promotes self-temperature rising to inhibit deposition without the need for additional heat insulation materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If heating methods are used to prevent deposition at the outlet port, then deposition prevention is improved, but device complexity and assembly steps increase due to additional heating components
Solution Approach 1:
The stator-side member utilizes its own thermal insulation properties to maintain elevated temperature and prevent deposition autonomously, without requiring external heating components. The member's design enables it to retain heat generated during pump operation, creating a self-regulating thermal environment that prevents product adhesion.
Solution Approach 2:
The patent changes the thermal conductivity parameter of the stator-side member by selecting materials with low thermal conductivity. This parameter modification allows the member to function as a thermal insulator, maintaining higher temperatures in the outlet port region to prevent deposition without adding external heating devices.
2Object-affected harmful factors
If heating methods are used to prevent deposition, then deposition prevention is improved, but the number of parts increases
Solution Approach 1:
The patent merges the thermal insulation function with the stator-side member itself, eliminating the need for separate heating components or insulating materials. The stator-side member is designed to inherently retain heat through material selection, combining structural and thermal management functions into a single component.
Solution Approach 2:
The stator-side member serves its own thermal management needs by utilizing materials with low thermal conductivity, eliminating dependence on external heating systems or additional insulating parts.
3Ease of manufacture
If the rotating body is manufactured from aluminum or aluminum alloy, then ease of manufacture is improved, but reliability deteriorates due to thermal expansion and creep at high speeds
Solution Approach 1:
The patent applies different material properties to different parts of the system. The rotating body uses aluminum or aluminum alloy for ease of manufacture, while the stator-side member uses materials with low thermal conductivity and high thermal stability to compensate for the rotor's thermal expansion and creep issues. This local differentiation of material properties allows each component to optimize its own characteristics while the system as a whole achieves reliability.
4Temperature
If thermal conductivity of the stator-side member is high, then heat dissipation is improved, but deposition increases due to temperature drop at the outlet port
Solution Approach 1:
The patent changes the thermal conductivity parameter of the stator-side member to a low value. This parameter change enables the member to retain heat and maintain elevated temperatures in the outlet port region, preventing the temperature drop that would otherwise cause product deposition.
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 prevents product deposition and adhesion, maintaining pump performance and reducing the risk of breakdown while simplifying assembly and operation by eliminating the need for extra heat insulation materials, thus ensuring stable and efficient operation.
Implementation Method 1
a threaded groove spacer (60) arranged in the vacuum pump, wherein a coefficient of thermal conductivity of the threaded groove spacer (60) is smaller than a predetermined value
Implementation Method 2
made from stainless steel with a lower conductivity than aluminum or aluminum alloys, which prevents heat conduction
Implementation Method 3
This configuration causes the thermal expansion of the rotor portion of the vacuum pump (the rotor blades in particular) and the creep phenomena in which the rotor portion becomes deformed
Implementation Method 4
the creep phenomena in which the rotor portion becomes deformed in the radial direction over time
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention provides a stator-side member which is arranged in a vacuum pump and which, without the provision of a heat insulation material, prevents the deposition of products at the lower side of a threaded groove pump unit, with this lower side being an area of high pressure where the deposition of products (deposits) occurs easily, and also provides a vacuum pump equipped with this stator-side member. A threaded groove spacer configured to have a coefficient of thermal conductivity lower than a predetermined value is arranged in a vacuum pump equipped with a threaded groove pump unit. (1) The threaded groove spacer is manufactured from a material having a coefficient of thermal conductivity lower than that of a member which opposes or comes into contact with the threaded groove spacer. Specifically, this material has a coefficient of thermal conductivity lower than that of aluminum or aluminum alloy, and is preferably any one of stainless steel, fiber-reinforced plastic, polyetherimide, and polyetheretherketone. (2) The threaded groove spacer is constituted by at least two or more parts.