Hot Dry Rocks Pty Ltd introduces what we believe to be the world’s first portable, electronic
divided bar machine for measuring the thermal conductivity of solid samples. HDR has
drawn on its extensive experience measuring thermal conductivity of rock samples, and
collaborated with a team with over a decade of experience building specialist geophysical
tools, to produce a design focused on functionality, portability and versatility, without
compromising on simplicity, accuracy and reliability.

A divided bar is a device that applies a steady thermal gradient
across a sample in series with a material of known thermal
conductivity. The thermal conductivity of the sample is calculated
by measuring the ratio of the thermal gradient across the sample
relative to that across the known material. A “conventional” divided
bar maintains the thermal gradient using thermostatically controlled
water baths. These baths are bulky and require AC power and
(usually) a source of running water to cool the pump motors. In
contrast, our device operates from a 12 volt DC power source (with
optional AC adapter) and requires no external cooling. The thermal
gradient is maintained to a high precision using electronic Peltier
devices, which have the ability to both heat and cool in response to
an applied electric current.

Features and specifications:

* 12 volt DC power supply, with AC converter
* Temperature at hot and cold plates kept constant to within ±0.02°C
* Temperature differential adjustable to 10°C, 15°C or 20°C
* Calibrated between 0.5–12 W/mK
* Achievable accuracy ±2%
* Takes samples up to 65 mm diameter
* Replaceable temperature measurement pads calibrated by HDR
* Simple controls
* Dimensions: approx 26 cm wide, 28 cm deep, 28 cm high
* Weight: approx 8 kg
* Robust construction

Advantages over a conventional divided bar:

* No water source required: Electronically heated and cooled
* Rapid measurement time: less than 5 minutes per sample is possible (after sample preparation)
* Field portable: Light, manoeuvrable and robust construction with field portability in mind
* Variable measurement temperature: 2.5°C increments over a range of ±10°C from air temperature
* Quiet
* Compact: Incorporates all major components of a conventional divided bar in one unit

 Contact HDR for more information