Optical Dilatometer for Metallic Samples
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Solution Overview
Problem
Existing dilatometers face errors due to heat dissipation at contact surfaces creating temperature gradients, which affect the correlation between measured temperature and length change, especially during phase transformations at high heating and cooling rates.
Innovation Solution
A non-contact optical dilatometer with an optical measuring device for length detection and a temperature sensor positioned in the measuring plane, avoiding heat dissipation and allowing accurate measurements even with temperature gradients, using a thermocouple with a small cross-section and an induction coil with a gap to accommodate the measurement plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based measurement stamps are used to measure sample length, then mechanical measurement is simple and direct, but heat dissipation occurs at contact surfaces creating temperature gradients that affect measurement accuracy
Solution Approach 1:
The patent replaces the mechanical contact-based length measurement system with an optical measurement system. A laser beam is directed at the sample, and a photodetector measures the position of reflected light to determine sample length. This substitution eliminates physical contact between measurement stamps and the sample, thereby preventing heat dissipation at contact surfaces and the resulting temperature gradients that compromise measurement accuracy.
2Reliability
If optical measurement is used to avoid heat dissipation, then temperature gradient issues are eliminated, but device complexity increases due to additional optical components
Solution Approach 1:
The patent implements an optical measurement system using a laser source, optical components (such as mirrors or beam splitters), and a photodetector array to measure sample length changes. This replaces the simple mechanical stamp contact method, increasing device complexity but eliminating heat dissipation at contact points and ensuring reliable measurements during phase transformations when temperature uniformity is critical.
Solution Approach 2:
The patent introduces light as an intermediary medium for measurement. Instead of direct mechanical contact, the optical system uses laser light reflected from the sample surface to convey length information to the photodetector. This intermediary approach allows measurement without physical contact, maintaining sample temperature uniformity while achieving the measurement objective.
3Measurement precision
If temperature sensor is placed close to measurement point, then temperature correlation is improved, but heat dissipation from sensor contact creates local temperature gradients
Solution Approach 1:
The patent replaces contact-based temperature sensing with non-contact optical temperature measurement. An optical pyrometer or infrared sensor measures the sample temperature by detecting thermal radiation emitted from the sample surface. This eliminates conductive heat dissipation from the sensor to the sample, preventing local temperature gradients while maintaining accurate temperature-length change correlation.
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 temperature-dependent length change measurements without heat dissipation, ensuring accurate detection of phase transformations by aligning the measurement plane perpendicularly to the sample's longitudinal direction and minimizing interference from the temperature sensor.
Implementation Method 1
an optical measuring device for detecting a change in length of the sample in a non-contact manner
Implementation Method 2
a sensor for measuring the temperature of the sample, in particular in the area of this plane
Implementation Method 3
The sample is heated by an induction coil
Data Source
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AI summary
The dilatometer (1) has a sample holder including a pair of clamping pins (4, 14) for receiving and clamping a metallic sample (3), and an induction coil (5) arranged on the metallic sample, where the induction coil heats the metallic sample. A sensor i.e. thermocouple, exactly measures temperature of the metallic sample in a region of a measuring plane of an optical measuring device. The optical measuring device detects change in length of the metallic sample in the measuring plane, and has a transmitter (6) and a receiver (9).