Vacuum Pump Flange Connecting Element for Crash Energy Absorption

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Solution Overview

Problem

Vacuum pumps with high-speed rotors face challenges in withstanding the high kinetic energies released during a rotor-stator crash, requiring a connection that enhances safety without compromising material stress or increasing costs.

Innovation Solution

A connecting element with a hook screw and cap design featuring a clamping bar that engages in the flange groove, optimizing leverage and material stress distribution, allowing for higher energy absorption and the use of softer materials, along with a form-fit mechanism and adaptive clamping surfaces to enhance security and reduce material stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotor speed and mass are increased to improve vacuum pump performance, then the kinetic energy stored in the rotor increases, but the risk and energy released during a rotor-stator crash increases, endangering the environment

Engineering Contradiction:
Improvevacuum pump performanceVSAvoidenvironmental danger from rotor-stator crash
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by designing a connection system with energy-absorbing elements (deformable connecting elements, prestressed springs, or controlled deformation zones) that are pre-configured to absorb kinetic energy during a rotor-stator crash. These elements are built into the connection between pump and chamber to mitigate the harmful effects before they can damage the environment.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the maximum rotor diameter and speed are limited to ensure safety, then the kinetic energy released during a crash is reduced, but the vacuum pump performance and productivity are constrained

Engineering Contradiction:
Improvesafety of connectionVSAvoidvacuum pump performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The connection system incorporates pre-designed energy absorption mechanisms including deformable connecting elements, prestressed springs, and controlled deformation zones that are configured to absorb kinetic energy during a rotor-stator crash, allowing higher rotor speeds and masses while maintaining safety.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies parameter changes by using connecting elements with variable mechanical properties (deformability, prestress levels) that change their behavior based on operating conditions. The connecting elements can operate in a rigid state during normal operation to maintain connection stability, but transition to a deformable state during a crash to absorb energy.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a conventional connecting element design is used, then the structure is simple, but the connection security is insufficient to withstand high kinetic energies from rotor-stator crashes

Engineering Contradiction:
Improveconnecting element structureVSAvoidconnection security
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The connection system incorporates pre-designed energy absorption mechanisms including deformable connecting elements, prestressed springs, and controlled deformation zones that are configured to absorb kinetic energy during a rotor-stator crash.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs composite material concepts by combining different material properties in the connecting elements - using materials with different deformation characteristics, strength levels, and energy absorption capabilities to create a composite connection system that can withstand and dissipate crash energies while maintaining connection security.

Inventive Principle:
Principle #40Composite materials

4Strength

If harder flange materials are used to withstand higher crash energies, then the connection strength increases, but the manufacturing cost and material stress increase

Engineering Contradiction:
Improveflange strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The connection system incorporates pre-designed energy absorption mechanisms that reduce the peak forces transmitted to the flanges during a crash, allowing the use of softer, more cost-effective flange materials while still maintaining adequate strength and safety.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 provides a secure and durable connection capable of handling higher rotor speeds and masses, enabling the use of cheaper materials and reducing the risk of damage during rotor-stator crashes while maintaining safety standards.

Implementation Method 1

A clamping length that is greater than the clamping distance prevents the connecting element from tilting about an axis in the flange plane, which can lead to the groove shearing off. The tilting moment arises, for example, in the case of a rotor-stator crash. Due to the ratio of clamping length to clamping distance according to the invention, the effective levers become more favorable and the material stress is reduced as a result.

Methodology Applied
Scientific EffectMechanical Advantage: Lever

Implementation Method 2

The parts are then prestressed, which causes the flanges to be pressed together in a vacuum-tight manner.

Methodology Applied
Scientific EffectMechanical Force: Force

Data Source

PatentEP2133581B1Connecting element
Publication Date: 2014.07.30 PFEIFFER VACUUM GMBH
  • EP2133581B1 patent drawingFigure 1
  • EP2133581B1 patent drawingFigure 2~3
  • EP2133581B1 patent drawingFigure 4

AI summary

The element (1) has circulating grooves (7, 8) arranged at standardized clamping flanges (2, 5) of a vacuum pump and a chamber, respectively. The grooves have a screw hook (9) and a casing (10) with respective clamping bars (11, 12) that are engaged with the grooves. Clamping length of the bars is larger than clamping distance according to DIN 28 404in a direction of the grooves. The hook is secured in the casing using a flange nut (14). Inner and outer radii of one bar are adapted to flange diameters, respectively. The hook is formed as a ring segment attached to the casing.