TCR24 DATA ACQUISITION SYSTEM FOR SOIL THERMAL CONDUCTIVITY

The measurement method used is based on the "unstable sensor technique" that uses a probe (also called a thermal needle), which uses a heating wire and a temperature sensor.
The probe is introduced in the ground and from its response when subject to a heating cycle for a few minutes, it is possible to calculate the thermal resistivity (or its opposite, the heat transmission).

The principle of the measurement is based on a peculiar characteristic of a rectilinear heat course (the heating wire of the probe). After a short transitional period, the increase of the temperature depends only on the heating power and heat transmission of the medium.
Once the first is known, the second can be then calculated.
The main applications of this technique consists of testing of high voltage cables and heating ducts.

General
Number of channels: 2
Power supply: 12 V DC internal lithium ion battery pack 10000 mAh
Acquisition medium power consumption: 350mA (150 mA display off)
Environmental conditions: Temperature (°C):-20 a 80; Humidity (RH): 0-90%
Connections: USB
Monitor: TFT-LCD capacitive 7” touch-screen, 1280x800
Data storage: SD memory up to 16 GB
Case: Polypropilene, automatic pressure valve, IP67
Dimensions: cm 225 x 270 x 107
Weight: 2,6 kg

Acquisition
A/D converter resolution: 24 bit
Temporal measurement resolution: 25 ms
Measurement interval: 300 - 1020 s

Acquired data can be examined directly on site, at the end of the acquisition phase regulated automatically by the device and it is expressed graphically and numerically in watt / (meters x kelvin) where: watt = unit of power; meter = unit of distance; kelvin = unit of temperature.
Operatively speaking, a hole is made into the ground using common drill (not supplied) and a perforation point of 20 mm diameter with prolonged rod (supplied).
The probe is then introduced into the hole and by pressing slightly, probe tip is fixed into the ground at about 20 cm, in order to obtain best coupling with soil.
Data acquisition is initiated by pressing a button, it is managed automatically by the instrument and lasts few seconds.
Numeric and graphic data is stored on SD memory and then elaborated with dedicated CTLAB software supplied together with the instrument.

Heat transmission of some types of soils:
- Dry loose rocks: +/- 1.5 W / m K
- Gravel, sand, water table: 1.8 2.4W / m K
- Granite: 3.4W / m K

Accessories supplied:
- CTS120 L probe = 120 cm.
- Aluminium case for the probe + tip
- Drilling tip 120 cm for the ground
- SD memory
- Battery charger
- Flycase for probe and drilling tip
- TC Reader software