Several companies manufacture freeze-point furnaces. Most of these furnaces are of adequate theoretical design and of reasonable quality. Most are priced similarly. However, there is a difference that can’t be seen from specifications or price, and that’s how well the furnace performs with the freeze-point cells they’re designed to maintain.

Establishing and maintaining a freeze-point plateau is what these furnaces are supposed to be about. Nothing they do is more important than this performance issue.

Hart Scientific makes three freeze-point furnaces that, when combined with Hart freeze-point cells, produce the longest plateaus in the industry. Generally, a Hart furnace and cell establish plateaus that range from 24 to 40 hours or more.

Fixed-point furnaces can also be used for comparison calibrations and for annealing. In these processes, stability and uniformity are very important, and nothing speaks more about stability and uniformity than the length of the plateaus produced by the furnace. No other furnace beats a Hart furnace where it counts.

All three of these furnaces have external cooling coils for circulation of tap water at less than 60 PSIG and approximately 0.4 GPM to reduce heat load to the lab. They also come with RS-232 ports and have equilibration blocks available for comparison calibrations. IEEE-488 interface packages are also available if that’s your preference.

One of Hart’s three fixed-point furnace models will meet your needs. Remember, the length of the plateau is the best measure of a furnace’s performance. Call us for performance data on actual cell freezes and test data on furnace gradients.


9115 
The Model 9115 Sodium Heat Pipe Furnace is specifically designed for maintenance of aluminum and silver freeze-point cells.

It has a temperature range of 550°C to 1000°C with gradients of less than ±0.1°C throughout. The sodium heat-pipe design provides a simple yet uniform single heating zone that ensures very uniform changes in states during heating and cooling.

Melting, freeze initiation, and plateau control for a variety of freeze-point cells are possible by entering up to eight set-points and ramp and soak rates. The controller displays temperature in degrees C or F, and temperature feedback is done via a type R thermocouple. Freeze-point plateaus of 8 to 10 hours are typical, and 24 hours is possible under controlled conditions

. External cooling coils are included for circulation of tap water to reduce chassis temperature and heat load to the lab. Temperature cutouts protect your SPRTs and the furnace from exposure to excessive temperatures.