Capillary Rheometer Structure for Curing Thermosetting Resins
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Solution Overview
Problem
Conventional rotational rheometers face challenges in accurately measuring rheological parameters during the curing process of thermosetting resins due to volume expansion and cross-linking reactions, which can cause damage and disrupt the measurement process.
Innovation Solution
A rheometer design featuring a piston assembly with a capillary tube and flow sensor, along with torque and rotational speed sensors, allows for continuous measurement of rheological parameters by monitoring force, flow rate, torque, and angular velocity during the curing process, using a capillary rheometer approach to account for volume expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional rotational rheometer with parallel plate fixture is used to measure thermosetting resin, then the measurement setup is simple, but the instrument may be damaged due to large normal stress from volume expansion and cross-linking reactions
Solution Approach 1:
A porous plate is introduced as an intermediary component between the sample and the measurement system. The porous plate allows volume expansion of the curing resin to be absorbed into its pores, preventing direct transmission of large normal stresses to the parallel plate fixture, thereby protecting the instrument while maintaining measurement capability
Solution Approach 2:
The measurement approach is changed from direct parallel plate contact to a system where the porous plate's porosity parameter allows volume change accommodation. By changing the structural parameter of the plate (making it porous), the system can handle the volume expansion during curing without damaging the instrument
2Measurement precision
If a conventional rotational rheometer is used for thermosetting resin measurement, then the initial measurement capability is adequate, but the measurement process must be stopped once curing occurs, affecting accuracy
Solution Approach 1:
The porous plate serves as a mediator that enables continuous measurement during curing. It accommodates volume expansion and allows the introduction of a capillary rheometer system that can measure throughout the entire curing process without interruption, providing continuous rheological data
Solution Approach 2:
The measurement system is enhanced to perform multiple functions: it can measure both before and during curing, accommodate volume expansion, and provide continuous rheological parameter tracking. The combination of porous plate and capillary rheometer creates a universal measurement system for thermosetting resins
3Reliability
If a capillary rheometer approach is used to account for volume expansion, then continuous measurement throughout curing is enabled, but the device complexity increases
Solution Approach 1:
The capillary rheometer system is nested within the existing rheometer framework. The porous plate is positioned at the base of the parallel plate fixture, and the capillary system is integrated into this structure, allowing the complex functionality to be embedded within the simpler existing system architecture
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 accurate and continuous recording of rheological parameters throughout the curing process, expanding the measurement range and optimizing results by preventing damage to the instrument and ensuring comprehensive data capture.
Implementation Method 1
a torque sensor and a rotational speed sensor are mounted on the rotating element, the torque sensor is configured to measure a torque of the sample in the first piston cylinder relative to the rotating element
Implementation Method 2
the rotational speed sensor is configured to measure an angular velocity of the rotating element
Implementation Method 3
a first force sensor is provided at a bottom end of the connecting rod for measuring a first force transmitted from a sample in the first piston cylinder to the lower piston
Implementation Method 4
a flow sensor is mounted at an inlet connecting the capillary tube to the bottom of the second piston cylinder, and the flow sensor is configured to measure a flow rate of a solution extruded from the capillary tube
Data Source
AI summary
A rheometer suitable for a thermosetting resin is provided, including a housing, a first piston cylinder disposed inside the housing, and a second piston cylinder connected to the first piston cylinder via a connecting rod. A capillary tube is mounted at a middle portion of a bottom of the second piston cylinder, and a container is mounted at an outlet of the capillary tube. A bottom end of the connecting rod is provided with a first force sensor for measuring a first force transmitted from a sample in the first piston cylinder to the lower piston; a rotating element is mounted inside the first piston cylinder, the rotating element is provided with a torque sensor and a rotational speed sensor for measuring a torque of the sample relative to the rotating element and an angular velocity of the rotating element, thereby determining rheological parameters of the sample during curing process.