Vacuum Pump Stator Cooling via Nested Aluminium Envelope
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Solution Overview
Problem
Vacuum pumps face reliability and performance issues due to heat generation, which causes metal deposition, clearance reduction, corrosion, and inefficient cooling, particularly with existing cooling methods like cooling plates and water jackets that limit heat removal and are prone to corrosion.
Innovation Solution
A laminated stator arrangement with a first part made from corrosion-resistant materials like SG iron, Aus-tempered ductile iron, or Ni-resist iron, and a second part made from thermally conductive aluminum, where the aluminum part is cast around the first part to form an intimate heat transfer interface and includes ducts for liquid coolant convection, enhancing heat conduction and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling plate assemblies are used to cool the pump stator, then heat removal is achieved, but the surface area limitation reduces the magnitude of heat that can be removed
Solution Approach 1:
The aluminium cooling part is cast around and envelops the iron stator core, creating a nested structure where the cooling surface area is significantly increased by wrapping around the stator. This nested configuration allows the cooling part to contact the stator over a large portion of its surface area, thereby removing heat more effectively than external cooling plates.
Solution Approach 2:
The invention uses a composite structure combining iron (for corrosion resistance and stator function) and aluminium (for thermal conduction and cooling). The aluminium cooling part is cast around the iron stator core, creating a composite assembly that leverages the complementary properties of both materials: iron's corrosion resistance and aluminium's high thermal conductivity.
2Temperature
If water jackets with direct cooling are used, then thermal efficiency is improved, but corrosion becomes a concern since many pumps are constructed from iron
Solution Approach 1:
The aluminium cooling part acts as an intermediary between the iron stator core and the cooling water. Instead of water directly contacting the iron stator (which would cause corrosion), the aluminium envelope serves as a protective barrier, allowing efficient heat transfer from the iron to the water while preventing corrosive interaction between water and iron.
Solution Approach 2:
The composite structure combines iron (corrosion-resistant to vacuum environment) and aluminium (thermally conductive and corrosion-resistant to water). This composite design allows the pump to achieve both thermal efficiency and corrosion resistance by assigning each material to the environment it resists best.
3Temperature
If cooling plates are secured to stator surfaces, then cooling is achieved, but other components may block access and prevent cooling plate attachment
Solution Approach 1:
The cooling part is integrated into the stator assembly by casting it around the stator core, creating a nested structure. This eliminates the need for separate cooling plates that would require attachment to external surfaces, as the cooling function is built into the stator itself through the nested aluminium envelope.
Solution Approach 2:
The invention merges the cooling function with the stator structure by casting the aluminium cooling part around the iron stator core. This integration combines what were previously separate components (stator and cooling system) into a single unified assembly, eliminating accessibility issues and simplifying the overall device structure.
4Reliability
If complex closed cooling systems with heat exchangers are used, then corrosion protection is improved, but system complexity and cost increase
Solution Approach 1:
The aluminium envelope provides inherent corrosion protection to the iron stator core, eliminating the need for complex external corrosion protection systems. The structure is self-protecting, as the aluminium naturally resists corrosion from cooling water, simplifying the overall system while maintaining reliability.
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 improves heat transfer efficiency, reduces the risk of corrosion, and allows for effective cooling without the need for complex closed systems, enhancing the reliability and performance of vacuum pumps by uniformly distributing heat across a larger surface area.
Implementation Method 1
heat generated in the first part can be transferred to the second part at the interface surface between the two parts
Implementation Method 2
at least one duct for conveying a liquid coolant through the second part so that heat can be transferred from the second part to the liquid coolant
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a pump (62) which comprises a rotor arrangement (64) and a stator arrangement (66). The stator arrangement comprises a first part (68) made from a corrosive resistant material which defines a volume (70) which in use is swept by the rotor arrangement for pumping fluid from an inlet (72) to an outlet (74) of the stator arrangement. A second part (76) of the stator arrangement is made from a thermally conductive material which envelopes the first part (68) so that heat generated in the first part can be transferred to the second part at the interface surface (78) between the two parts. The second part (76) has formed therein at least one duct (80) for conveying a liquid coolant through the second part so that heat can be transferred from the second part to the liquid coolant for cooling the stator arrangement.