In the practical world of temperature measurement, a large number of laboratories who normally make comparison calibrations need 1 or 2 fixed points to monitor their Standard Platinum Resistance Thermometers, or would like to calibrate shorter thermometers than the larger cells and apparatus can accept. For this group of users Isothermal Technology Limited has introduced the Metal Clad Fixed Point Cells.
The special requirements of immersion depth, plateau duration, etc. required for the calibration of SPRT's may not be necessary in laboratories charged with calibrating industrial resistance thermometers, thermocouples and thermistors, but mobility and cost may be more important. Metal Clad Cells is a name given to another category of cell, being somewhat slimmer, slightly shorter and lower in price than the standard varieties. Metal Clad Cells are built using the same materials, techniques and purity of metal as the larger cells, but the uncertainties associated with them are somewhat larger, not because of the cells but precisely because their shorter immersion depth results in a decreased ability to qualifying them.
In consequence of their smaller size, small, lighter-weight apparatus (bench-top or cart-mounted furnaces) may be used to melt and freeze the metal in these cells. Sealed cells and associated apparatus, such as the Model 510— Medusa and Model 580— Oceanus-6, are available.
