Thermtest-en

Thermtest THW-L1

The Thermtest Transient Hot Wire (THW-L1) liquid thermal conductivity equipment is an advanced measurement system for direct determination of the thermal conductivity liquids and pastes in accordance with ASTM D7896-19 – Standard Test Method for Thermal Conductivity of Engine Coolants and Related Fluids by Transient Hot Wire Liquid Thermal Conductivity Method.

The THW-L1 Meter was designed with speed and operational simplicity in mind. With a single measurement of 1 second in duration, small volumes of liquids and low viscosity pastes can be accurately and precisely measured for thermal conductivity, thermal diffusivity, and specific heat. The THW-L1 Meter uses a non-stationary measurement approach and rapid test times, limiting convective effects for samples with a wide range of viscosities (0.1 to 10,000,000 mPas).

The Transient Hot Wire (THW) sensor consists of a thin heating wire, 40 mm in length, which is fully immersed in the sample to be tested. The wire is heated using a constant current source (q), and the resulting temperature rise is determined by monitoring the change in its electrical resistance. The slope (m) obtained from the plot of temperature rise versus the natural logarithm of time, log(t), is used to calculate the thermal conductivity (λ) of the sample.

For liquids with high thermal conductivity, the slope of the curve is smaller, while for liquids with low thermal conductivity, the slope is larger. Continuous measurement of temperature rise as a function of log(time) produces a linear relationship, and the slope of this line provides the basis for determining the fluid’s thermal conductivity.

Specifications

Materials: Liquids and PCMs
Thermal conductivity (W/m•K): 0.01 to 2
Additional Properties: Thermal diffusivity and specific heat
Viscosity range (cP): 0.001 to 10,000,000
Sample size (mL): 20
Test time (seconds): 1
Accuracy (Thermal conductivity)*: 2%
Repeatability (Thermal conductivity)*: 1%
Temperature range (°C): -40 to 200
Pressure (bar): Up to 20
Standard: ASTM D7896-19

*All performance data is verified by manufacturer with ASTM Type II Water (IAPWS)

FAQ

Our company would like to cooperate with you. What is the procedure?

Please contact us first using the form below and we will arrange an introduction meeting. During the introduction meeting, we will discuss your requirements and wishes and present the device in more detail. On this basis, we will prepare an offer for you. The measurements will start when all necessary components are delivered. After the measurements, we will arrange another meeting to review the results and agree on additional analyzes. In the end, you will receive the results in the form of a report.