Gas Flow Seal Pressure Cell for Oscillatory Shear Measurement

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Solution Overview

Problem

Existing devices cannot effectively measure the elasticity of low-viscosity liquids at high pressures and high temperatures, as they either fail to account for both properties simultaneously or restrict mobility due to sealing methods.

Innovation Solution

A measuring device with a gas flow seal between two rotating parts, allowing for friction-free sealing and torque measurement, enabling the determination of elasticity and viscosity under high pressures and temperatures up to 200°C and 16 bar, using a three-way gas flow seal and oscillating movement to maintain pressure and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid seal is used between measuring device parts, then sealing effectiveness is improved, but measurement precision deteriorates due to friction and torque distortion

Engineering Contradiction:
Improvesealing effectivenessVSAvoidtorque measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs a gas flow seal where compressed gas flows through a narrow gap between the first and second measuring device parts, creating a pressure field that prevents medium leakage without solid contact. This pneumatic sealing mechanism eliminates friction between rotating parts while maintaining effective sealing under high pressure conditions.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Measurement precision

If a gas flow seal is used between measuring device parts, then measurement precision is improved by reducing friction, but device complexity increases due to the three-way construction

Engineering Contradiction:
Improvetorque measurement accuracyVSAvoidsealing mechanism structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The gas flow seal structure serves multiple functions simultaneously: it seals the gap between rotating parts, provides lubrication through the gas film, and acts as a bearing support. This multi-functionality reduces the need for separate sealing, lubrication, and support mechanisms, thereby managing complexity despite the three-way construction.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If high pressure is maintained in the measurement volume, then reliability of high-pressure measurement is improved, but ease of operation deteriorates due to restricted mobility of measuring parts

Engineering Contradiction:
Improvehigh-pressure measurement capabilityVSAvoidmobility of measuring parts
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The gas flow seal enables the first measuring device part to rotate freely within the high-pressure medium by maintaining a pressurized gas film in the gap between parts. This pneumatic bearing effect supports the rotating part without solid contact, eliminating friction that would otherwise restrict mobility under high pressure conditions.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enables precise measurement of elasticity and viscosity of low-viscosity liquids at high pressures and temperatures without impairing mobility, maintaining high pressure and allowing for accurate torque determination, thus overcoming the limitations of prior devices.

Implementation Method 1

a gas flow seal (50), which seals the first measuring device part (10) to the second measuring device part (20) from one another

Methodology Applied
Scientific EffectGas flow seal: Air Lubrication

Implementation Method 2

measuring device for measuring an elasticity and a viscosity of a medium... in oscillatory shear under pressure

Methodology Applied
Scientific EffectOscillatory shear: Vibration

Data Source

PatentEP3245499B1Pressure cell for rheological experiments in oscillatory shear under pressure
Publication Date: 2021.08.11 WATERS GMBH
  • EP3245499B1 patent drawingFigure 1
  • EP3245499B1 patent drawingFigure 2~3

AI summary

The invention relates to a measuring device for measuring an elasticity and a viscosity of a medium, comprising a first measuring device part, which has a volume for receiving the medium to be measured, and a second measuring device part, which projects into said volume. The first measuring device part is sealed from the second measuring device part by means of a gas flow seal. A rotary movement about a predetermined axis can be imparted on the first measuring device part can be relative to the second measuring device part.