HFM-50 HEAT FLOW METER

The Heat Flow Meter (HFM-100 and HFM-50) is an easy-to-use technique for the measurement of thermal resistance and thermal conductivity of insulation products, construction materials, packaging, and assemblies. Thermal conductivity is a measure 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.

• Two flux sensors with surface thermocouples for accurate measurement of thermal resistance and thermal conductivity
• Multiple 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 new feature packed HFM-100 / HFM50 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, C1784, ISO 8301, JIS A1412, EN 12667, and EN 12664

 

The second generation HFM-100 / HFM-50 instrument is an excellent choice when making steady-state thermal conductivity measurements of specimens such an insulation products and construction materials. Thermtest has rigorously engineered the Heat Flow Meter (HFM) to meet the requirements of international standards including ASTM C518, C1784, ISO 8301, JIS A1412, EN 12667, and EN 12664. 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 applied pressure, 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 measure thermal resistance (R) and calculate thermal conductivity (λ) according to Fourier’s Law.







Following international standards, the HFM-100 is designed for testing both homogeneous and heterogeneous materials. The HFM-100 / HFM-50 sample size allows for representative testing of materials typically found in insulation and construction industries.
 

Materials	Insulation, Solids, and Textiles
Type of Sensors	Flux Sensors (x2)
Surface Thermocouples	Three for each flux sensor
Applications	General Testing
Direction	Through-Thickness
Thermal Conductivity Range	0.002 to 0.5 W/m•K (0.001 to 3.5 BTU/(hr·ft·°F))
Specific Heat Capacity	Optional
High Thermal Conductivity Kit	Up to 2.5 W/m•K (17.3 BTU/(hr·ft·°F))
Measurement Time	30 to 40 min
Reproducibility	± 0.5 to 1%
Accuracy*	± 1 to 2%
Plate Temperature Range†	-20 to 70°C
HFM-100 Sample Size	Up to 300 x 300 x 100 mm
HFM-50 Sample Size	Up to 200 x 200 x 50 mm
Standard	ASTM C518, C1784, ISO 8301, JIS A1412, EN 12667, and EN 12664

  Method is continually improved; specifications are subject to change without prior notice.
^*Performance verified with NIST 1450d / 1450e
^†Chilled circulator required