Integrated Vacuum Pump Motor Design for Sealed Unit Reliability
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Solution Overview
Problem
Existing vacuum pumping systems rely on dynamic seals, which are expensive and unreliable, and are bulky and heavy, making them difficult to ship and install, especially in space-constrained applications, and are prone to oil leaks and flexure stresses.
Innovation Solution
The motor stator and rotor are integrated within the pumping chamber of the vacuum pump, eliminating the need for dynamic seals and allowing for a compact, lighter design with static seals, which reduces noise and vibrations and increases reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is placed outside the pumping chamber and connected via a dynamic seal, then the motor can drive the pump rotor, but the dynamic seal causes oil leaks and reduces reliability
Solution Approach 1:
The motor is integrated within the pumping chamber, merging the motor housing with the pump housing. This eliminates the dynamic seal interface between the motor and pump, thereby preventing oil leaks and improving reliability. The motor rotor is coupled directly to the pump rotor through a shared drive shaft within the same sealed environment.
Solution Approach 2:
The motor is extracted from the external environment and placed inside the pumping chamber, removing the need for a dynamic seal that connects the motor shaft to the pump rotor across pressure boundaries. This extraction eliminates the source of oil leaks associated with dynamic seals.
2Weight of stationary object
If the motor is placed outside the pumping chamber, then the motor can be cooled by ambient air, but the system becomes bulky and heavy
Solution Approach 1:
The motor housing is merged with the pump housing, creating a single integrated structure. This eliminates the need for separate motor and pump housings, reducing the overall volume and weight of the system while maintaining all necessary functions.
Solution Approach 2:
The motor is nested within the pumping chamber, with the motor housing forming part of the pump housing structure. This nested arrangement allows the motor to occupy space within the existing pump envelope, reducing the overall system volume and weight without compromising motor functionality.
3Device complexity
If the motor is placed outside the pumping chamber, then the motor can be easily replaced, but the system requires dynamic seals that increase complexity
Solution Approach 1:
The motor and pump are merged into a single integrated unit, eliminating the dynamic seal interface. This simplification removes a critical failure point while maintaining the ability to service the system by replacing the entire integrated motor-pump assembly as a single unit.
4Reliability
If the motor is placed inside the pumping chamber, then dynamic seals are eliminated and reliability increases, but the motor must operate in a vacuum environment
Solution Approach 1:
The motor is merged with the pump housing and operates within the same sealed chamber. This design adapts the motor to operate in the vacuum environment by integrating it into the pump's sealed housing, eliminating the need for the motor to adapt to external atmospheric conditions 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 enhances the reliability and compactness of the vacuum pumping system, reduces the risk of oil leaks, and decreases power absorption and noise, leading to improved performance and longer working life.
Implementation Method 1
The motor stator and a motor rotor are received in the pumping chamber of the vacuum pump... the motor stator and the motor rotor, as well as the pump stator and the pump rotor, are entirely received in said pumping chamber
Data Source
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AI summary
The present invention relates to a vacuum pumping system (50) comprising a vacuum pump (10) and a motor (40) for driving said vacuum pump. According to embodiments of the invention, the motor stator (42) and the motor rotor (44) are received in the pumping chamber (16) of the vacuum pump. Thanks to such arrangement, the vacuum pumping system according to embodiments of the invention can be made as a single, sealed unit and the need for dynamic seals can be avoided. Moreover, the vacuum pumping system can be more compact and lighter that the vacuum pumping systems of prior art. According to a preferred embodiment of the invention, the pump rotor (18) is at least partially made as a hollow body and the motor (40) is received inside said pump rotor.