TLS-100 Transient Line Source

The TLS-100 is a portable meter used to measure thermal conductivity and thermal resistivity of a variety of samples, including soil, rocks, concrete, and polymers.

Best for soil, rock, concrete, and polymers
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TLS 100

Features

The TLS-100 is a portable meter used to measure thermal conductivity and thermal resistivity of a variety of samples, including soil, rocks, concrete and polymers. Tests are performed with the push of a button and results are displayed instantly. The TLS-100 features sensors that are auto-recognized with corresponding testing parameters automatically loaded.

The TLS-100 follows ASTM D5334-22a and IEEE 442-2017. The sensor needle consists of a thin heating wire and temperature sensor sealed in a 150, 100 or 50 mm steel tube. The sensor is completely inserted into the sample to be tested. Heat is delivered to the sample using a constant current source (q) and the temperature rise is recorded over a defined period of time. The slope (a) from plot of temperature rise versus logarithm of time is used in the calculation of thermal conductivity (k). The higher the thermal conductivity of a sample, the lower the slope. For samples of low thermal conductivity, the slope will be higher.

TLS-100 equation
  • Follows international standards: ASTM D5334-22a and IEEE 442-2017
  • Economical, smart and accurate
  • Easy to use
  • Standard 100 mm / 150 mm sensor for soft materials
  • Standard 50 mm sensor for hard materials

Specification

Method

TLS-100 (Included)

TLS-50

TLS-150

TLS-100 vCp

Materials

Soils, pastes, powders and solids

Concrete, rocks and polymers

Soils, pastes, powders and solids

Soil, solids, pastes, and powders

Thermal conductivity (W/m·K)

0.1 to 5

0.3 to 5

0.1 to 3

N/A

Thermal resistivity (mK/W)

0.2 to 10

0.2 to 3.3

0.3 to 10

N/A

Volumetric specific heat (MJ/m³K)

N/A

N/A

N/A

Up to 2.5

Smallest sample size (mm)

100 length, 50 diameter

50 length, 50 diameter

150 length, 50 diameter

100 length, 50 diameter

Largest sample size (mm)

Unlimited

Unlimited

Unlimited

Unlimited

Test time (minutes)

3

3

3

N/A

Accuracy (Thermal conductivity)

5%

5%

5%

15%*

Repeatability (Thermal conductivity)

2%

2%

2%

2%

Temperature range (°C)

-40 to 100

-40 to 100

-40 to 100

-40 to 100

Standard

ASTM D5334-22a, IEEE 442-1981

N/A

ASTM D5334-14, IEEE 442-2017

N/A

*Specific heat

Testing Sensors

TLS-100 sensor

Standard 100 mm Sensor

Each TLS-100 comes equipped with the standard 100 mm sensor for testing of soil, soft materials, polymers, and easy to drill materials. The needle sensor is fully inserted into an isothermal sample and a measurement is made with the push of a button. After 180 seconds, results are displayed for thermal conductivity and thermal resistivity. Saved results can also be exported to a computer, via convenient utility software and USB connection.

TLS-50 sensor

Standard 50 mm Sensor

The 50 mm sensor was designed for testing hard samples like rock and concrete. Drilling the required 4 mm diameter x 50 mm hole in rigid samples is easy with the provided masonry drill bit. When testing hard samples, a thermal contact grease is used to enhance contact between the sensor and sample.

Standard 150 mm Sensor

The optional 150 mm sensor is used for in-lab and in-field testing of soil and soft materials according to IEEE 442-2017. The needle is fully inserted into an isothermal sample and measurement is made with the push of a button. After 180 seconds, results are displayed for thermal conductivity and thermal resistivity.

Customer Reviews

The TLS -100 instrument from Thermtest that we purchased has been effective and reliable for measuring the thermal conductivity of the samples in our concrete laboratory. Daniel from Thermtest has been extremely helpful right from the beginning when we considered purchasing this instrument until today with his advice and technical support. He answered all the queries that I had about the instrument and the measurement technique even prior to the purchase. All in all, I am very happy that we chose Thermtest and thank them for providing us with their excellent customer service.

— Ruchita Jani, Postgraduate Researcher at TU Dublin

We purchased the TLS-100 last year and it has been already become an invaluable part of our R&D process. The TLS-100 is very user friendly and gives us repeatable results which gives us confidence. The Thermtest customer service has been great too. Thanks!

— Johan du Plessis, CEO at Tepeo

The TLS-100 device is used in our laboratory for the testing of soil samples. The aim of the measurement is to test the soils as backfill material for high voltage power cables. In our measurements we test the soil at different water contents. Compared to devices from other manufacturers, the TLS-100 is a reliable and precise measuring device. A special advantage is the short measuring time and an excellent customer service.

— Dr.-Ing. Steffen Trinks, Pedotec GmbH Berlin

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