Vacuum Pump Cartridge Heater Slit Design
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Solution Overview
Problem
Existing vacuum pump apparatuses used in semiconductor manufacturing and other processes face challenges in maintaining a high temperature in the rotor chamber and easily replacing the heater, as the heater is often sandwiched between side covers, requiring disassembly for replacement.
Innovation Solution
A vacuum pump apparatus design featuring a cartridge heater with a heater casing that has a slit, allowing for thermal expansion and easy attachment/removal, and is positioned in a side cover or pump casing, enabling efficient heat transfer and maintenance without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is sandwiched between side covers to maintain high temperature in the rotor chamber, then the temperature control is effective, but the heater cannot be easily replaced when it ends its service life
Solution Approach 1:
The heater assembly is segmented into a heater body and a separate heater casing, where the heater casing can be removed independently from the side covers. This segmentation allows the heater to be accessed and replaced without removing the entire side cover assembly, resolving the contradiction between maintaining effective temperature control and enabling easy heater replacement.
Solution Approach 2:
The heater is extracted from the sandwiched position between side covers by introducing a heater casing that can be removed. The heater casing acts as an intermediary component that can be taken out along with the heater, allowing replacement without disassembling the side covers. This extraction principle directly addresses the ease of repair requirement while preserving the temperature control function.
2Reliability
If the heater is firmly fixed to ensure stable heating, then the temperature maintenance is reliable, but the heater becomes difficult to remove for replacement
Solution Approach 1:
The heater casing is designed with a dynamic attachment mechanism that provides firm fixation during operation to ensure stable temperature maintenance, but allows easy removal when replacement is needed. The slit in the heater casing enables thermal expansion during heating while the attachment structure can be engaged or disengaged as required, resolving the contradiction between reliability and ease of repair.
Solution Approach 2:
The attachment mechanism of the heater casing utilizes parameter changes, specifically thermal expansion and contraction, to achieve both firm fixation during operation and easy removal during maintenance. The slit in the heater casing allows for thermal expansion parameter changes while the attachment structure maintains stable connection during operation, enabling both reliability and ease of repair.
3Reliability
If the heater casing is made of a material with high thermal expansion to accommodate heater expansion, then the heater deformation is prevented, but the heater casing requires special material selection
Solution Approach 1:
The heater casing is made of a material with higher thermal expansion coefficient than the heater body, allowing the heater casing to expand and contract with the heater during thermal cycles. This thermal expansion principle prevents deformation and maintains the integrity of the heater assembly, resolving the contradiction between reliability and ease of manufacture by using a well-known material property.
Solution Approach 2:
The heater assembly uses composite material selection where the heater casing is made of a material with different thermal expansion characteristics compared to the heater body. This composite approach allows each component to be optimized for its specific function while working together harmoniously, preventing deformation without requiring overly complex material selection.
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 design effectively maintains a high temperature in the rotor chamber, prevents deformation of the cartridge heater, and allows for easy replacement, ensuring stable operation and reducing maintenance costs.
Implementation Method 1
a cartridge heater disposed in the side cover or in the pump casing and removably attached to the side cover or the pump casing, wherein the cartridge heater has a heater and a heater casing covering at least a part of the heater
Implementation Method 2
the heater casing has a slit extending from one end to other end thereof... the slit formed in the heater casing can absorb thermal expansion of the heater and the heater casing
Data Source
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AI summary
A vacuum pump apparatus capable of maintaining an inside of a rotor chamber (1) of a pump casing (2) at a high temperature and capable of being easily attached and removed a heater (70A,70B) is disclosed. The vacuum pump apparatus includes: a pump casing (2); a pump rotor (5) arranged in the rotor chamber; a rotation shaft (7) to which the pump rotor is fixed; an electric motor (8) coupled to the rotation shaft; a side cover (10a, 10B) forming an end surface of the rotor chamber; a housing structure located outwardly of the side cover in an axial direction of the rotation shaft; and a cartridge heater (70A, 70B) disposed in the side cover and removably attached to the side cover or the pump casing. The cartridge heater has a heater and a heater casing (71) covering at least a part of the heater, and the heater casing has a slit ( 72A) extending from one end to other end thereof.