HEAT FLOW METER
THERMAL CONDUCTIVITY MEASUREMENT SYSTEM
The HFM-100 Heat Flow Meter method is an easy-to-use rapid technique for thermal conductivity measurement and thermal resistance testing of insulation products, construction materials, packaging, and assemblies. A measurement of thermal conductivity is an indicator of the ability of a material to conduct heat and can be critical for defining energy efficiency and thermal performance in materials. The Thermtest HFM has been designed and engineered to combine the highest accuracy, repeatability, widest temperature range, and industry-leading performance, all at an exceptional value. Follows international standards: ASTM C518, ISO 8301, and EN 12667.
FEATURED HEAT FLOW METER METHOD CAPABILITIES
- Two flux sensors for accurate measurement of thermal conductivity
- Peltier heating / cooling plates for rapid control of temperature
- Thickness is measured to an accuracy of 0.05 mm (0.0019 in) with the use of four digital optical encoders
- Front panel operation allows full control of all HFM functions, or use the intuitive HFM Software for basic and additional functions, such as printing and exporting
- Plate clamping can be automated or set to a user defined thickness — ideal for compressible materials
- Follows international standards: ASTM C518, ISO 8301, and EN 12667
The cost effective HFM 100 Heat Flow Meter instrument is an excellent choice when making steady-state thermal conductivity measurements of specimens such as insulation products and construction materials. Thermtest has rigorously engineered the heat flow meter to meet the requirements of international standards including ASTM C518, ISO 8301, and EN 12667.
Operating the HFM is straightforward — a sample is positioned between two heating – cooling plates, and the upper plate, powered by stepper motors positioned in each corner, lowers to contact the top of the sample. Plate contact with the test specimen is controlled by a standard pressure applied, or by a user defined specimen thickness. Stepper motors are controlled by individual optical encoders for measurement of sample thickness (L), to the nearest 0.05 mm (0.0019 in). Integrated logic between stepper motors allows the upper plate to sense and adjust for specimens with surface variations, optimizing plate – specimen contact for measurements.
One heat flux sensor is integrated into each plate, and is used to monitor heat flux (Q/A), generated due to the difference in temperature (ΔT) between the top and bottom plate at regular intervals, until steady-state heat flux is observed. The composite heat flux is then used to calculate thermal conductivity (λ) and thermal resistance (R) according to Fourier’s Law.
HFM 100 SPECIFICATIONS
Method is continually improved; specifications are subject to change without prior notice.
*Requires chilled circulator.
ACCURACY & REPEATABILITY OF THE HEAT FLOW METER METHOD
A sample of NIST SRM 1450d was repeatedly tested to confirm the accuracy and repeatability of the heat flow meter method. Prior to each of 20 measurements, the NIST 1450d sample was removed, and then placed back within the HFM-100 chamber. The certified thermal conductivity for the NIST piece at 20˚C (68˚F) is 0.03239 W/mK (0.2246 BTU/(hr·ft·°F)). The average thermal conductivity value received from all 20 tests was 0.0325 W/mK (0.2253 BTU/(hr·ft·°F)). All tests had a repeatability within 0.5%, and an accuracy within 1% of the certified value.
HIGH THERMAL CONDUCTIVITY KIT
With the added High Thermal Conductivity Kit, the HFM-100 is able to accurately, and efficiently measure higher thermal conductivity materials, such as glass and ceramics. For such applications, an external thermocouple kit is used in combination with the sample being tested. Macor, Quartz, and Pyrex were tested in the HFM from 10˚C to 60˚C (50˚F to 140˚F). All measured values are within the stated accuracy of the system, +/- 5%.
HEAT FLOW METER METHOD HIGHLIGHTS
Video link: https://www.youtube.com/watch?v=hweduimIO0w