Diaphragm Vacuum Pump Self-Calibration for Dead Volume Reduction

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Solution Overview

Problem

Membrane vacuum pumps face challenges with limited compression ratios due to dead volumes and require high manufacturing precision, which cannot be adjusted if the membrane wears out, leading to suboptimal performance and increased costs.

Innovation Solution

A self-calibration method using a control device with a voice coil drive to detect and adjust the dead center of the piston, allowing for automatic calibration before operation, reducing manufacturing tolerances and improving final pressure and pumping efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the membrane is pressed tightly against the membrane head to eliminate dead volume, then the compression ratio is improved, but the membrane wear increases leading to premature failure

Engineering Contradiction:
Improvecompression ratioVSAvoidmembrane service life
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing an automatic calibration run before the pump is put into operation. During this calibration, the piston is operated with reduced force to move the membrane into the membrane head and determine the optimal dead center position. This preliminary positioning eliminates dead volume for optimal compression ratio while preventing excessive force that would cause premature membrane wear, thus resolving the contradiction between compression ratio and membrane service life.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If high manufacturing precision is used to eliminate dead volume, then the compression ratio is improved, but the manufacturing costs increase

Engineering Contradiction:
Improvecompression ratioVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by introducing an automatic calibration process that determines the optimal dead center position of the piston based on actual operational parameters rather than relying solely on precise manufacturing tolerances. The calibration run adjusts the piston position to achieve optimal membrane contact with the membrane head, eliminating dead volume and improving compression ratio without requiring higher manufacturing precision, thus reducing manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the piston stroke is increased to improve pumping speed, then the productivity is improved, but the dead center positioning becomes more critical affecting reliability

Engineering Contradiction:
Improvepumping speedVSAvoiddead center positioning accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies feedback by using a device for detecting the dead center and position of the piston, with a control device that adjusts the dead center based on the detected signal. This feedback mechanism ensures accurate dead center positioning even with increased piston stroke for higher pumping speed, maintaining reliability while improving productivity.

Inventive Principle:
Principle #23Feedback

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 self-calibration method enhances the membrane vacuum pump's performance by optimizing the dead center, reducing dead volumes, and minimizing wear, resulting in improved final pressure and pumping speed while reducing manufacturing costs and time.

Implementation Method 1

a piston (2) which can be driven linearly with a voice coil drive (7, 8) in a drive chamber (15)

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2889481B2Method for calibrating a membrane vacuum pump and membrane vacuum pump
Publication Date: 2022.10.26 PFEIFFER VACUUM GMBH
  • EP2889481B2 patent drawingFigure 1~2
  • EP2889481B2 patent drawingFigure 3~4
  • EP2889481B2 patent drawingFigure 5

AI summary

The invention relates to a method for calibrating a diaphragm vacuum pump and a diaphragm vacuum pump for conveying a medium, comprising a piston linearly driven by a voice coil drive in a drive chamber, a diaphragm oscillating between a conveying chamber and a drive chamber, separating the conveying chamber and the drive chamber, a diaphragm head forming the conveying chamber with the diaphragm, the piston being designed as a piston that sets the diaphragm in motion and is movable by a predetermined distance, and a device for detecting a dead point and/or position of the piston, wherein a control device adjusts the dead point depending on the detected signal of the device.