Turbo-Molecular Pump Gas Venting Grooves for Leak Reduction

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Solution Overview

Problem

Turbo-molecular pumps experience slow leaks due to gas confinement in hermetic spaces between rotor discs and the shaft, leading to prolonged time in achieving high-vacuum states and potential adverse effects on mass analysis and leak detection results.

Innovation Solution

Incorporating gas venting grooves at the interfaces between rotor discs and the shaft, which act as communication paths to facilitate the discharge of confined gas into the pump exhaust path, thereby preventing slow leaks and ensuring rapid vacuum achievement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rotor discs are firmly fixed to the shaft using fitting methods to avoid looseness or detachment, then structural stability is improved, but hermetic spaces are formed that cause slow leaks

Engineering Contradiction:

Improvestructural stabilityVSAvoidslow leaks

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful gas from the hermetic clearance space by providing a communication path that allows the gas to be discharged to the exhaust side, thereby removing the harmful factor while maintaining the firm fitting structure

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The communication path acts as an intermediary channel between the clearance space and the exhaust path, allowing controlled discharge of trapped gas without compromising the structural integrity of the fitting connection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If hermetic spaces are formed between rotor discs and shaft, then gas confinement occurs, but this leads to prolonged time to achieve high-vacuum states

Engineering Contradiction:

Improvevacuum pumping performanceVSAvoidtime to achieve vacuum state

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The communication path is pre-established in the structure to enable immediate discharge of trapped gas when the pump operates, preventing gas accumulation and reducing the time required to achieve vacuum state

Inventive Principle:

Principle #10Preliminary action

3Productivity

If multiple rotor blade stages are stacked on the shaft, then pumping capacity is improved, but clearance spaces between stacking portions create leak paths

Engineering Contradiction:

Improvepumping capacityVSAvoidleak paths

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the clearance space into multiple discrete regions between different stacking portions, with each segment having its own communication path to the exhaust, preventing interconnected leak paths while maintaining multi-stage pumping capacity

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11359988B2Vacuum pump and leak detector

Publication Date: 2022.06.14 SHIMADZU CORP

AI summary

A vacuum pump comprises: a pump rotor portion configured such that multiple rotor blade stages including stacking portions formed in a ring shape and turbine blades radially formed on an outer peripheral side of the stacking portions are stacked on each other; a rotor shaft to which inner peripheral surfaces of the stacking portions of the multiple rotor blade stages stacked on each other are fixed; and a communication path allowing communication between a clearance space between the rotor shaft and each stacking portion and a pump exhaust path in which the turbine blades are arranged and discharging gas in the clearance space through the pump exhaust path.