Thermal conductivity tester for measuring the thermal conductivity of rock wool

Rock wool is an inorganic fiber material made mainly from natural rocks through high-temperature melting and fibrosis. It has characteristics such as low thermal conductivity, high fire resistance, sound absorption and noise reduction, and is widely used in building exterior wall insulation, industrial equipment insulation and other fields. Thermal conductivity is the core indicator for measuring the insulation performance of rock wool, and its accurate testing is crucial for material research and development, engineering design, and energy-saving evaluation.

Traditional thermal conductivity testing methods (such as laser flash method and hot wire method) are mostly suitable for isotropic, high thermal conductivity or semi transparent solids, while rubber, as a soft and low thermal conductivity material, has problems such as high contact thermal resistance and long testing time. The transient planar heat source method synchronously heats up the sample through a planar heating probe embedded in the sample, and uses the temperature response characteristics to invert the thermal conductivity. It has the advantages of non-destructive, fast, and wide measurement range, and is particularly suitable for thermal conductivity testing of porous and soft materials such as rubber.

1、 Operation steps of the experiment

1. Measuring instrument: DZDR-AS thermal conductivity tester

2. Measured samples:

Select three commercial rock wool samples with different densities (A, B, C), and the basic parameters are shown in the table:

3. Measurement operation steps

Sample pretreatment: Cut the rock wool sample into circular thin sheets with a diameter of 100mm, remove surface dust, and place it in a constant temperature and humidity chamber for 48 hours to eliminate the influence of moisture during transportation and storage.

Instrument calibration: Use standard acrylic sheets for instrument calibration to verify the accuracy of the testing system.

Sample clamping: Lay the sample to be tested flat on both sides of the probe, gently press to ensure close contact between the probe and the sample, and ensure no bubbles.

Testing process: Start the instrument, set the heating time (usually 160 seconds), and record the real-time temperature change data of the probe over time.

Data collection and storage: Export the original temperature time curve and automatically calculate the thermal conductivity through the instrument's accompanying software.

4. Measurement spectra and data analysis

4.1 Measurement Chart:

The repeatability test results of thermal conductivity for different samples are shown in Table 2 (ambient temperature 23 ℃, relative humidity 50%):

The results showed that the relative standard deviation (RSD) of all samples was less than 3%, indicating that the transient heat source method has good repeatability in testing the thermal conductivity of rock wool.