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| Furnaces for the Primary Laboratory | |
| Annealing Furnace Model Model 414 | |
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For annealing SPRTs and other thermometers |
 From Databook 1 |
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 Data Sheet |
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| The Annealing Furnace, model 414, is designed to heat, anneal and cool SPRT’s (Standard Platinum Resistance Thermometers) prior to calibration. The temperature range of the Furnace - from ambient to 1000ºC enables all types of SPRT’s to be annealed. One of the duties of a calibration laboratory manager is to ensure that the SPRT’s used in the Laboratory are fully annealed and still within specification. Just using the thermometers within the laboratory will cause work-hardening to take place within the platinum coil of the SPRT. Therefore regular annealing is required to ensure the SPRT’s are in an ideal condition. In 1990 the new temperature scale ITS-90 specified the use of SPRT’s up to the Silver point (961.78ºC). At these temperatures quartz is very porous and in reducing atmospheres the SPRT’s can quickly become contaminated. The Isotech Annealing Furnace offers a safe solution for those who wish to anneal SPRT’s up to 1000ºC. To prevent contamination at high temperatures a constant flux of pre-heated air passes the SPRT’s being annealed. A comprehensive handbook accompanies the Furnace. This Furnace is installed simply and requires no maintenance. A ceramic equalizing block is available comprising a closed ended tube, Alumina tubes to house the sensors being compared, and Alumina powder to act as an equalizing media. |
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