Positive-Displacement Pump Pressure Absorber for Flow Stability

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Solution Overview

Problem

Volumetric pumps for viscoelastic products like rubber in tire manufacturing experience unpredictable and variable pressure variations due to the axial elongation of the pump body and screw, leading to irregular output flow rates.

Innovation Solution

A volumetric pump design featuring a booster element with an absorption body axially secured to the screw, which absorbs the pressure from the pressurization chamber, preventing axial elongation of the pump body and maintaining constant pressure and flow rates by distributing the pressure exerted on the screw and absorption body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the pump body and screw are allowed to deform axially under pressure, then the pump can accommodate pressure variations, but the metering chambers and circulation channels experience volume variations causing irregular output flow rate

Engineering Contradiction:
Improveoutput flow rate regularityVSAvoidpump body structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The pump body is segmented into a fixed portion and a movable portion that can deform axially independently. The fixed portion contains the metering chambers and circulation channels, while the movable portion absorbs pressure variations through axial deformation. This segmentation isolates the sensitive metering components from pressure-induced deformations, maintaining flow rate regularity without requiring complete structural rigidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A counter-pressure mechanism is introduced that applies an opposing axial force to balance the pressure variations in the pressurization chamber. This counteracting force prevents the metering chambers from experiencing volume changes, thereby maintaining constant output flow rate. The counter-pressure system acts as a mechanical compensation that offsets the harmful effects of pressure fluctuations.

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

2Stability of the object's composition

If the pump body is made rigid to prevent axial elongation, then the output flow rate remains regular, but the pump cannot accommodate pressure variations

Engineering Contradiction:
Improveoutput flow rate regularityVSAvoidpressure accommodation capability
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The pump body is divided into a rigid fixed portion containing the metering chambers and a flexible movable portion that accommodates pressure variations. The fixed portion maintains structural integrity and volume stability for regular flow output, while the movable portion provides the necessary compliance to absorb pressure fluctuations through controlled axial deformation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A pressure absorption mechanism serves as an intermediary element between the pressurization chamber and the metering chambers. This intermediary component absorbs the pressure variations before they can affect the metering chambers, protecting the sensitive volumetric components from pressure-induced volume changes while allowing the pump to handle varying pressure conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If the axial pressure is distributed on multiple elements (pump body and screw), then the pressure is better absorbed, but the axial elongation of pump body causes volume variations in metering chambers

Engineering Contradiction:
Improvepressure distributionVSAvoidmetering chamber volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The elements subjected to axial pressure are segmented into those that can deform (movable portion, pressure absorption mechanism) and those that must maintain constant volume (fixed portion containing metering chambers). This segmentation ensures that pressure distribution occurs across compliant elements while the volumetric components remain dimensionally stable, preventing flow rate irregularities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A pressure absorption mechanism acts as an intermediary that intercepts and absorbs axial pressure before it can be transmitted to the metering chambers. This intermediary element bears the compressive forces, preventing them from causing volume variations in the metering chambers while still allowing effective pressure distribution throughout the pump system.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This design ensures a regular output flow rate by stabilizing the pressure within the metering chambers and circulation channels, reducing variations in pressure and flow rate, thus improving the pump's efficiency in processing viscoelastic materials.

Implementation Method 1

the boosting element comprises a body for absorbing the pressure of the pressurization chamber axially secured to the screw and separate from the screw, the absorption body having a surface delimiting the pressurization chamber

Methodology Applied
Scientific EffectPressure absorption: Absorption (physical)

Implementation Method 2

the pressure exerted on the pump body in the pump of the state of the art is absorbed by the booster element, in particular by the part of booster element between the absorption body and the screw of the pump according to the invention. Thus, the pressure exerted by the rubber in the pressurizing chamber is exerted on the same element, here the booster element, more particularly on the screw and the absorption body. As the absorption body is fixed axially to the screw, only the booster element deforms to a limited or even non-existent manner.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2422087B1Positive-displacement pump including a pressure absorber
Publication Date: 2018.01.24 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP2422087B1 patent drawingFigure 1A~1B
  • EP2422087B1 patent drawingFigure 2

AI summary

The invention relates to a positive-displacement pump (10) including a pump body (12) defining a chamber (14) for pressurizing gum, and an element (16) for feeding the chamber (14) with the gum. The feeding element (16) includes an auger (42) rotatably movable about a main axis (X) relative to the pump body (12) and a body (50) for absorbing the pressure of the pressurizing chamber (14) axially secured to the auger (42). The absorption body (50) is separate from the auger (42) and has a surface (54) defining the pressurizing chamber (14) and arranged axially opposite the auger (42).