UNITHERM ™ 2022
GUARDED HEAT FLOW METER THERMAL CONDUCTIVITY MEASURING SYSTEM

To request a quote, please fill out our Request for Particulars form.

The Unitherm™ Model 2022 is used to measure thermal conductivity of a variety of materials. These include polymers, ceramics, composites, glasses, rubbers, some metals, and other materials of low to medium thermal conductivity. Only a relatively small test sample is required. Non-solids, such as pastes or liquids, can be tested using special containers. Thin films can also be tested accurately using a multi-layer technique. The tests are in accordance with the ASTM E1530 Standard. GUARDED HEAT FLOW METER TEST METHOD A sample of the material is held under a uniform compressive load between two polished surfaces, each controlled at a different temperature. The lower surface is part of a calibrated heat flow transducer. The heat flows from the upper surface, through the sample, to the lower surface, establishing an axial temperature gradient in the stack. After reaching thermal equilibrium, the temperature difference across the sample is measured along with the output from the heat flow transducer. These values and the sample thickness are then used to calculate the thermal conductivity. The temperature drop through the sample is measured with temperature sensors in the highly conductive metal surface layers on either side of the sample.

-20°C to 300°C Guarded Heat Flow Meter Fully computerized operation 1'', 1.5'', or 2'' dia. sample ASTM E1530

Each instrument is factory calibrated using samples of known thermal resistance, spanning the particular range. The contact resistance is kept small by applying a reproducible, pneumatic load to the test stack, and if needed, a thermally conductive interface compound. A guard furnace surrounds the test stack to reduce the effect of heat transfer across the edges of the sample. For testing at temperatures below ambient, the device is supplied with an airtight compartment, where the atmosphere can be kept relatively moisture free with dry air purge. Polymers can be tested through the melt using special containment cells. Also, special containment cells are available for fluids, pastes, and powders.

It typically takes from 45 to 60 minutes to complete a test at a temperature.

It is unavoidable to have a substantial temperature difference between the cold face of the sample and the heat sink. For this reason, a city water cooled heat sink allows operation with a lowest sample temperature of about 50°C. To fully utilize the range of the instrument, the optional chiller circulator is used, that can provide heat sink temperature to -10°C. The instrument is provided with one of three operating range modules. Each module covers a different thermal resistance region. The various modules are field exchangeable.

FULLY COMPUTERIZED SYSTEM

includes Windows™ operating and data analysis software (PC not included). The user must specify certain test parameters, including sample size and desired test temperatures, and the equipment runs unattended until test completion, when thermal conductivity results are printed and plotted. Requires RS-232 serial port and USB port.

OPTIONAL FEATURE

include an adjustable Constant Thickness Stop, which prevents the ram to squeeze the sample out if it happens to soften. This eliminates the need for the commonly employed spacers, which are difficult to use. (Available after September 2006)

OPTIONAL CHILLERS

P/N 106831 for temperature range 0°C to 300°C
P/N 106832 for temperature range -20°C to 300°C
*City water not required when accessory chiller is provided.

To request a quote, please fill out our Request for Particulars form.
Specifications are subject to change without notice.