Vacuum Pump Disc Rotor Asymmetry Balancing

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Solution Overview

Problem

Existing vacuum pumps with regenerative and drag pumping mechanisms face issues due to unbalanced disc-shaped rotors, leading to problems in certain pumping conditions, particularly at high speeds and varying pressures.

Innovation Solution

A vacuum pump design featuring a disc-shaped regenerative pumping mechanism and a cylindrical drag pumping mechanism, where the disc-shaped member has rotor formations on opposing sides cooperating with complementary stator portions to create balanced parallel fluid flow paths, and a gas bearing arrangement to maintain axial clearance, with the cylindrical member made of lightweight materials to reduce inertia and bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a disc-shaped rotor is used in the regenerative pumping mechanism, then the pumping efficiency is improved, but the rotor becomes unbalanced under varying pressure conditions, causing mechanical problems

Engineering Contradiction:
Improvepumping efficiencyVSAvoidrotor balance
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The rotor design incorporates asymmetric pressure distribution compensation features. The disc-shaped rotor includes balancing elements that create counteracting forces to compensate for the asymmetric pressure forces generated during operation. This allows the rotor to maintain balance despite the inherently asymmetric pressure conditions in the regenerative pumping mechanism.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention employs counterbalancing masses or balancing elements integrated into the disc-shaped rotor structure. These counterweights are strategically positioned to offset the unbalanced forces generated by the pressure differential across the rotor surfaces, thereby maintaining rotational balance and preventing mechanical problems.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Productivity

If the disc-shaped member rotates at high speeds, then the pumping performance is improved, but mechanical stress and instability increase

Engineering Contradiction:
Improvepumping performanceVSAvoidmechanical stress
Core Design Contradiction:
ProductivityVSStress or pressure

Solution Approach 1:

The rotor and stator are designed with pre-established geometric configurations and clearance specifications that optimize performance at high rotational speeds. The disc-shaped member's shape, the positioning of rotor formations, and the clearance with stator components are predetermined to minimize mechanical stress and maximize pumping performance at the intended high operating speeds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes critical parameters such as rotational speed, clearance dimensions, and geometric configurations to achieve high-performance operation. By carefully selecting and adjusting these parameters, the system achieves high pumping performance while keeping mechanical stress within acceptable limits.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If rotor formations are added to the disc-shaped member, then the fluid pumping capability is improved, but the device complexity increases

Engineering Contradiction:
Improvefluid pumping capabilityVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The disc-shaped rotor is divided into multiple functional zones with rotor formations distributed across its surface. These segmented rotor formations (such as vanes, ribs, or patterned structures) are arranged in specific zones to perform different pumping functions, allowing complex pumping capabilities to be achieved through modular, organized structures rather than a single complex design.

Inventive Principle:
Principle #1Segmentation

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 achieves balanced forces and efficient fluid flow, reducing leakage and enhancing pumping performance across a wide pressure range from atmosphere to high vacuums, with improved balance and reduced mechanical stress at high speeds.

Implementation Method 1

an axial gas bearing arrangement is located at an inner circumference of the generally disc-shaped member 16 for maintaining an axial clearance X between the disc-shaped member and the stator

Methodology Applied
Scientific EffectGas bearing: Air Lubrication

Implementation Method 2

rotation of the disc-shaped member and the cylindrical-shaped member by the axial shaft causes fluid to flow radially inwardly in series through the drag pumping mechanism and the regenerative pumping mechanism

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2956674B1Vacuum pump
Publication Date: 2019.05.01 EDWARDS LTD
  • EP2956674B1 patent drawingFigure 1

AI summary

The present invention relates to a vacuum pump (10) comprising a regenerative pumping mechanism (12) and a drag pumping mechanism (14). The regenerative pumping mechanism (12) comprises a generally disc-shaped member (16) mounted on an axial shaft (8) for rotation relative to a stator (20) of the regenerative pumping mechanism. The drag pumping mechanism (14) comprising a generally cylindrical-shaped member (22) mounted at an outer circumferential portion (24) of the disc-shaped member (16) for rotation about the axial shaft (18) relative to a stator of the drag pumping mechanism.