Highlights
TCT 716 Lambda - Between Classical Heat Flow Meters and Laser Flash Analyzers
The TCT 716 Lambda offers the capability of analyzing specimens with optimum dimensions: smaller than conventional HFM and larger than LFA. This enables investigations on homogeneous and inhomogeneous materials with Conductivité ThermiqueThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity values ranging from low to medium, for example polymers, composites, glass, ceramics, some metals, etc.
The robust design of the TCT 716 Lambda thermal conductivity tester offers easy, uncomplicated handling of the software and hardware. The guarded heat flow meter (GHFM) is fully software-controlled, including mean temperature and applied force. The software also allows for an unlimited number of steps in test cycles for best performance
This GHFM has a left and right test stack; which enables tests on a single specimen or simultaneous tests on two specimens. Each stack is independent of the other in terms of clamping force and specimen thickness. Both stacks can be operated across the entire temperature range from -10°C to 300°C. This arrangement not only increases sample throughput, but also allows for more data to be collected in less time.
The system provides precise temperature control with a resolution of 0.1°C. It is equipped with multiple high-resolution detectors (RTD), which allow for accurate measurement of the thermal gradient across stack and specimen thickness.
Cost-Effective Cooling
CO2 is a natural refrigerant that provides sustainable and energy-efficient cooling in everything from warehouses to ice machines – including the TCT 716 Lambda!
CO2 features unique thermophysical properties:
- Very good heat transfer coefficient
- High energy content
- Relatively insensitive to pressure losses
- Very low viscosity Unlike other GHFMs, this design allows for CO2 cooling for optimal temperature control.
There is no longer any need for an expensive chiller unit. In addition, forced cooling of the instrument is possible and CO2 consumption above ambient temperature is low.
Method
Thermal Conductivity - A Key Parameter for Improved Energy Efficiency
Thermal conductivity is a measure of a material's ability to conduct heat. It quantifies how well heat can move through a substance. The most common method for measuring thermal conductivity is the steady-state method, also known as the heat flow meter method.
In this method, a sample of the material with known dimensions is placed between two plates of different temperatures. One plate is heated, while the other is cooled, creating a temperature gradient across the material. Heat flows through the sample from the hot plate to the cold plate. The rate of heat transfer (heat flux) and the temperature difference across the sample are measured.
Using Fourier's law of heat conduction, which relates the heat flux, temperature gradient, and thermal conductivity of the material, the thermal conductivity of the sample can be calculated. This calculation accounts for factors such as the dimensions of the sample and the thermal resistance at the interface between the sample and the plates.
By repeating the measurements with different samples and under various conditions, the thermal conductivity of the material can be accurately determined. This information is crucial for evaluating the insulation properties of materials used in building construction, electronics, and various other applications where heat transfer is a concern.
TCT 716 Lambda - Principle of Operation
The operator measures the thickness of the test specimen(s), and places them between two heated plates controlled at different temperatures. Temperature sensors (RTD) are mounted just below the plate surfaces for measuring the temperature drop across the specimen. Similar sensors are also embedded in the upper and lower stacks (metering area: 51 mm) to measure the heat flow through the specimen. Once steady-state condition has been achieved, these signals are collected for calculating thermal conductivity. The software indicates thermal equilibrium. After the indication of thermal equilibrium, the measurement is carried out.
NETZSCH offers more products that support you in measuring Thermal Conductivity:
Specifications
| TCT 716 Lambda | |
|---|---|
| General | |
| Standards | Based on ASTM E1530 |
| Operation | External PC, minimum i5 or equivalent, 500 GB, 2x USB 3.0 (not included) |
| Automated instrument calibration | Yes; reference materials: fused silica; pyroceram and stainless steel |
| Testing chamber | Motorized door opening/closing mechanism, interlocked |
| Measurement data | |
| Thermal resistance range | 0.001 ... 0.030 m2·K/W |
| Thermal conductivity range | 0.1 … approx. 45 W/(m·K) (using proper sample thicknesses) |
| Thermal conductivity accuracy | ±3% deviation from literature value (depending on the accuracy of calibration material) |
| Thermal conductivity repeatability | ±2% (precision; measurement of the same sample in the same device after sample out/in between measurements |
| Measurement times for different material types | In general, t < 2 hours/point, depending on range, number of temperature steps and conductivity |
| Number of set points | Free-selectable number of programmable test temperatures; typically full range test includes 5 to 6 test temperatures max. |
| Number and type of temperature sensors | Premium RTD class A, in protective capsule, 14 total/instrument, resolution: 0.01°C |
| Metering area of the plates | 51 mm, round, full cross section |
| Sample Dimensions | |
| Sample shapes | Round |
| Sample dimensions | ø 51 mm nominal (2 in; +0.005 in, -0.050 in); height up to 31.8 mm (1¼ in) |
| Sample condition | Solid |
| Number of samples | Up to 2; independent of type, identical thermal cycles |
| Contact force and load control | |
| Variable contact force | Programmable for incompressible materials |
| Contact pressure/accuracy | 5 … 50 psi ± 5 psi |
| Load control | Automatic |
| Temperature | |
| Temperature |
|
| Temperature gradient | Typically 30 K, variable |
| Cooling system | Liquid CO2 |
| RTD resolution | ±0.05%, class A RTD, approx. ±0.01°C resolution |
| Locations of temperature measurement | Specific locations along stack, consisting of upper plate/sample/lower plate, heat sink |
| Instrument Dimensions | |
| Dimensions and weight | 460 mm (18”) wide, 630 mm (25”) deep, 510 mm (20”) high, 80 lbs (without CO2 cylinder) |
| CO2 cylinder | mandatory for operation (not included) |
Samples
Typically, the TCT 716 Lambda allows for measurements on round solid specimens in the low- and medium-conductive range such as polymers (filled and unfilled) and low-conductive ceramics and metals including porous specimens. An important feature of the instrument is that there are no temperature sensors embedded into the sample. Sample preparation is according to ASTM E1530. For solid specimens, a thermal interface paste is used to improve the thermal contact with the instrument plates
Advantages of the GHFM
The GHFM provides a reliable and precise method for measuring the thermal conductivity and thermal resistance in a wide variety of solids, thus contributing to materials science research and product development.
- High accuracy: uncertainties typically < 3%
- Non-destructive test: The materials to be tested can be measured as made without destroying or otherwise altering them
- Wide range of materials: metals, polymers, ceramics, composites, etc.
- Specimen dimensions: 51 mm in diameter, up to 31.8-mm thickness – advantageous for inhomogeneous samples
- Easy to use: typically only minimal training required
Brochures and Data Sheets:
Proven Excellence in Service
At NETZSCH Analyzing & Testing, we offer a comprehensive range of services globally to ensure the optimal performance and longevity of your thermoanalytical equipment. With a track record of proven excellence, our services are designed to maximize the effectiveness of your devices, extend their lifespan, and minimize downtime.
Unlock the full potential of your equipment with our tailored solutions, backed by years of industry expertise and innovation.
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