UNITHERM™ 1091
MULTI-SAMPLE DILATOMETER
This instrument is a fully computerized dilatometer system designed to measure dimensional changes of a specimen brought about by changes in its thermal environment. Linear thermal expansion coefficient, annealing characteristics and other physical or chemical changes manifesting themselves in a change of linear dimension can be precisely determined. Studies of processing parameters as reflected by dimensional changes of the material can be studied in great detail through duplication of thermal cycles and rates used in the actual process. Due to the flexible programming of thermal cycles, complex processes can be easily simulated.
The digital displacement transducer used in the system is an absolute device with no periodic calibration requirements. It is free of short term drift and long term changes, as its accuracy is based on a very stable internal glass grating whose movement is optically monitored. The dual pushrod universal model (2 or 4 samples) may be operated either as a two sample absolute or a conventional differential dilatometer.
• Cryogenic to 500°C,
Ambient to 1000/1200°C
• Single, dual, or 4 sample
• Research quality
• Fast cycle options
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FEATURES COMMON TO ALL COMPUTERIZED INSTRUMENTS
The Unitherm™ line features fully computerized systems designed to measure the various thermophysical properties of solids. All instruments in this family of devices use the Windows™95 or later platform to interface the control computer. In most cases, multiple unit operation is possible.
An extensive tutorial is supplied with each instrument to allow self-teaching of the operation. On-line help screens are available in every phase of the program, greatly minimizing the need of referring back to the manual in case of questions while setting up or running a test.
Computer and Peripherals
A current model PC can be provided with the instrument to carry out the control and data analysis functions. For specifics, please inquire at the time purchase of the device is contemplated.
Temperature Programming and Control
The system offers a user programmable mix of ramps, dwells, soaks, and printing rates, delayed start, repeat-cycle capability with a program capacity of 16 thermal cycles (64 segments), and the ability to store and recall frequently used programs. The temperature program is fully displayed and is editable during a run. All vital test parameters are continuously displayed and updated. Digital temperature control with optimized adaptive routines is used to achieve accurate sample, rather than furnace, temperatures. Internal logic is included for thermal equilibrium (where applicable) and for optimized cycles.
Data Recording
Measured data is recorded in the form of page print-out and is continuously stored on disk for further analysis. All test and program parameters along with system correction and standards data are also stored in each test data set for easy comparison of tests at a later date.
System Correction and Thermocouple Linearization
Built-in system correction and calibration tables than can be verified or altered if desired are included. System correction can be altered, based on calibration runs with NIST standards or other references. All thermocouple signals are precisely linearized using look-up tables.
Data Reduction, Analysis, and Reporting
Stored data is automatically processed by statistical methods, either for equilibrium points only, (which are sorted out on user selected criteria), or for all points (such as with ramp heating, where applicable). The analysis includes polynomial curve fitting, evaluation of the equation at user selectable points or intervals, and tabulation of results, (such as percent expansion, average coefficient, and instantaneous coefficient, thermal conductivity, specific heat, etc.) as a function of temperature. A variety of single or multiple curves for a group of tests can be generated, displayed, and hard copies produced using the printer.
The extremely user-friendly, fully integrated, proprietary software (developed in C++ specifically for each instrument) is totally transparent to the user and requires no computer programming knowledge. Optionally, data files may be downloaded to other computers for further processing.
Safety and Diagnostic Features
An extensive array of safety provisions ensure that operational malfunctions of each key part will not cause catastrophic failure of the system or destruction of the specimen. Open thermocouple, loss of water flow, four levels of furnace and sample over-temperature, and dead computer detection are among the functions that are continuously monitored. Certain ones will automatically shut down the equipment while others summon the operator via audio-visual indicators. Built-in diagnostic routines allow the operator to exercise and interrogate the failed system to determine the cause. All circuitry is homogeneously integrated on three circuit boards which can be swapped out in a matter of minutes for quick repairs.
