Whilst heat pipe furnaces offer the ideal environment to melt and freeze ITS-90 Fixed Points the temperature range is limited by fluid that flows inside the pipe. Three zone furnaces can offer wider operating ranges and still meet the requirements for “Optimal Realization of the Defining Points of the ITS-90…” CCT/2000-13. In place of a heat pipe the Model 465 3 Zone High Temperature Furnace uses top and bottom guard heaters to minimise temperature gradients. This more recent addition to our long-established range of metrology furnaces offers an alternative for those who prefer 3-Zone furnaces to heat pipe technology and need high temperature operation. The three zones create a controlled volume of constant temperature within the furnace in which High-Temperature Fixed Points such as Aluminium, Silver and Copper can be frozen and melted. Because High-Temperature thermometers can be easily contaminated by metallic vapors, great care has been taken to eliminate the use of metals throughout the calibration volume. The cell holder is made of alumina. 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. This 3-Zone Furnace can be used for the realizations of Zinc, Aluminium, Silver, Gold and Copper points, or with an optional equalizing block used for annealing or comparison calibration. New Features From our own ongoing experience and customer feedback we have updated the Isotech Furnace Range to deliver the same proven performance and advanced features but with a number of convenience upgrades to make your life easier. The controllers have now been relocated to the top for easier operation, we now include an SPRT Stand and Cable Tidies to keep your standards safe and Accessory Pods to keep the furnace tops free from clutter. Our furnaces are programmable to automatically melt and freeze cells and feature both USB and Ethernet interfaces with bright crystal clear displays.