DVD 1650DVD 1650 高温立式热膨胀仪的详细介绍
The DVD-1650 is a fully computerized dilatometer system designed to measure dimensional changes of a specimen brought about by changes in its thermal environment. This instrument measures linear thermal expansion coefficient (CTE), shrinkage attendant to sintering, phase transformations,
annealing characteristics, and other physical or chemical changes manifesting in a change of a linear dimension. Processing parameters 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.
DVD-1650 Features
• The high-temperature furnace is constructed of low thermal mass fibrous alumina insulation surrounding molybdenum disilicide (MoSi2) heating elements. Four hairpin-shaped elements act as eight linear heat sources equally spaced around the muffle tube (parallel to its axis). Length-to-diameter ratios are chosen to ensure excellent hot zone uniformity.
• 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 vertical configuration of this instrument makes it especially suitable for testing ceramic materials where shrinkage often outweighs expansion. In a horizontal specimen holder, shrinkage of a specimen can cause it to pull away from the end plug (unless extensive push-rod force is applied), 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 to operate the dilatometer as a Thermomechanical Analyzer (TMA). Optional program modules allow softening point determination
and controlled-rate sintering cycles.
• The counter-balanced dilatometer head slides vertically on guide rods to extract the specimen holder (dilatometer tube) from the furnace cavity. When ***ed, 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 dilatometer head, are water cooled.
• The standard alumina dilatometer tube and pushrod are readily interchangeable with a fused silica assembly for pecial applications. System correction for the tube is automatically made in software. The device automatically imits maximum furnace temperature (to 1000°C) when the fused silica tube is in place.
Technical Specification
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