With Heat Flow Meter
Thermal Conductivity Measuring Devices with Heat Flow Meter according to ISO 8301, ASTM C518, DIN EN 1946-3, EN 12664, EN 12667, EN12939
Devices with heat flow meter are primarily used in the industry for quality and production control because they deliver reliable measuring results within a very short time. Adherence to the required calibration routine ensures that these devices achieve nearly the same accuracy as devices with guarded hot plate.
Schematic diagram of heat flow meter method
Heat flow meter devices use one or several heat flow measuring plates to determine the heat flow density q in (W/m²). Their possible layout is defined in the standard ISO 8301, section 184.108.40.206.
The TCA device from NETZSCH TAURUS Instruments is designed according to the one-plate-principle with two symmetrically arranged heat flow measuring plates according to ISO 8301, section 220.127.116.11, figure 1b. This measuring method is an indirect method with the heat flow meters generating a voltage signal equivalent to the heat flow and therefore need to be calibrated.
Basis for calculation of lambda:
The electrical signal of the heat flow meters is proportional to the heat flow density q in (W/m²). According to the standard, the device must be calibrated with materials having similar heat transfer characteristics as the materials to be evaluated.
The necessary calibration factor is determined by measuring a certified sample. This value is saved in the calibration file of the software and should be checked on a regular basis.
The thermal conductivity is calculated with the following equation:
|λ= (q * d) / ΔT||q:
|Heat flow density in [W/m²]
Sample thickness in [m]
Temperature difference in [K]
Field of application:
Determination of the thermal conductivity and the thermal resistance of insulating, building and construction materials