Rolling Diaphragm Pump Shape Stability During Flushing

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Solution Overview

Problem

In diaphragm pumps used for chemical liquid replacement, the rolling diaphragm's curved portion distorts when maximally projected, leading to inefficient liquid discharge and potential product failures due to liquid stagnation, requiring excessive cleaning liquid and time.

Innovation Solution

The diaphragm pump design incorporates a thick outer circumference ring portion and a thin-film annular extraction portion, ensuring the rolling diaphragm maintains a smoothly curved extended attitude even at maximum projection, preventing distortion and facilitating efficient liquid discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the piston is maximally projectively moved to the maximum projecting position in flushing mode, then the folded portion of the rolling diaphragm is extended to discharge liquid, but the curved portion becomes distorted forming edge portions or reversely bent portions that prevent complete liquid discharge

Engineering Contradiction:
Improveliquid replacement efficiencyVSAvoidshape accuracy of curved portion
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the rolling diaphragm by introducing a support rib structure that modifies the deformation characteristics of the diaphragm. The support rib prevents excessive distortion of the curved portion during maximal piston projection, maintaining the smooth arcuate shape needed for complete liquid discharge while still allowing the folded portion to extend for flushing operations.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the curved portion is allowed to distort during maximal piston projection, then the structure can accommodate large volume changes, but liquid stagnates in the distorted folded portion requiring excessive cleaning liquid and time

Engineering Contradiction:
Improvevolume change accommodationVSAvoidcleaning liquid consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The support rib structure modifies the deformation parameters of the rolling diaphragm during piston movement. It maintains the ability to accommodate large volume changes while preventing the curved portion from distorting into shapes that trap liquid, thereby eliminating the need for excessive cleaning liquid and time.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the support rib is positioned too close to the outer circumferential portion, then the curved portion maintains smooth shape, but the folded portion cannot extend properly for liquid discharge

Engineering Contradiction:
Improveshape accuracy of curved portionVSAvoidfolded portion extension capability
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The support rib is strategically positioned at a specific distance from the outer circumferential portion (0.05 to 0.15 times the thickness of the rolling diaphragm) to create local structural reinforcement only where needed. This local quality approach maintains the smooth shape of the curved portion while preserving the extension capability of the folded portion for proper liquid discharge.

Inventive Principle:
Principle #3Local quality

4Duration of action of moving object

If the rolling diaphragm is made thinner for flexibility, then it can deform more easily during piston movement, but the curved portion becomes more prone to distortion and liquid stagnation

Engineering Contradiction:
Improvediaphragm flexibilityVSAvoidcurved portion shape stability
Core Design Contradiction:
Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The patent uses a thin-film rolling diaphragm for flexibility but incorporates a support rib structure that prevents excessive distortion. The support rib is positioned and dimensioned to provide just enough structural reinforcement to maintain curved portion shape stability during maximal piston projection while preserving the diaphragm's flexibility for normal pumping operations.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2775143B1Diaphragm pump
Publication Date: 2018.11.07 NIPPON PILLAR PACKING CO LTD
  • EP2775143B1 patent drawingFigure 1
  • EP2775143B1 patent drawingFigure 2
  • EP2775143B1 patent drawingFigure 3

AI summary

A diaphragm pump is provided in which, when a rolling diaphragm is set to an extended attitude by projectively moving a piston as far as possible, a curved portion that is formed by opening a folded portion does not have a distorted shape, but has an expected shape that is smoothly curved, whereby the liquid quantity and time period that are required for a liquid replacement in a flushing mode can be reduced, and the liquid replacement efficiency is improved. In a diaphragm pump having: a fluorine resin-made rolling diaphragm 3 including: an inner circumferential portion 3c which elongates along an outer circumferential surface 2e of a piston 2; an outer circumferential portion 3e which elongates along the inner circumferential surface 1r of a cylinder 1; and a folded portion 3d which is formed by folding back in a tubular space 13 between the cylinder 1 and the piston 2; and a pump chamber 4 which is separated by the rolling diaphragm 3 in the cylinder 1, the rolling diaphragm 3 is produced in an extended attitude corresponding to an attitude obtained when, by a projective movement of the piston 2, the outer circumferential portion 3e is eliminated, and the folding of the folded portion 3d is opened.