UNITHERM ™ 1101
HIGH TEMPERATURE VERTICAL DILATOMETER

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

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, shrinkage attendant to sintering, phase transformations, annealing characteristics, and other physical or chemical changes manifesting themselves in a change of a 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 extensive programming available to produce thermal cycles, complex processes can easily be 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. In special instances, an analog sensor is added with an automatically calibrating coupling mechanism, to further increase resolution. Optional program modules allow softening point determination and controlled rate sintering cycles. The vertical configuration of this device makes it especially suitable for testing ceramic and powder pressed materials where shrinkage often outweighs expansion. In a horizontal sample holder, shrinkage of a sample can cause it to pull away from the end plug, resulting in erroneous data. Vertical configurations are not subject to this problem. Pushrod tracking forces are governed by variable dead weight counter-balancing, and can be reduced to very low values. Optionally, specific pushrod loading can also be applied through additional weights on a pan. The dilatometer head slides vertically on guide rods to extract the sample holder (dilatometer tube) from the furnace cavity. The smoothly functioning, head-lifting mechanism is counter-balanced with constant force springs. When inserted, sliding hermetic seals engage the muffle tube collar to provide a protective environment for the specimen. Critical components, such as the ends of the muffle tube and the seals engaging it, along with the base of the head, are water cooled. System correction for the tube is automatically made in software. This system meets and in many respects exceeds requirements set forth in ASTM E-228 Standard.

-150 to 500°C or ambient to 1000/1200°C Single or dual sample Extra large samples Rapid cool down from 500°C Carbon anode applications ASTM

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™ 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.

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