The Centorr Model 5TA Reed Tri-Arc Furnace is a natural evolution of the Centorr Model 5SA Single Arc Furnace. The furnace system consists of the Tri-Arc Furnace, a Resistor box, a D.C. power supply and a set of water cooled power cables to bring power and water to the furnace. Because of its simplicity, ease of access, and small column, the furnace is easily purged. Work specimens are, therefore, quickly prepared, with a very high degree of purity maintained from sample to sample.
Our Model 5Ta Reed Tri-Arc Furnace was developed for the scientist engaged in high temperature work requiring more elaborate apparatus than that normally used for arc melting applications. (For the everyday arc melting applications, see our data sheet on the Centorr Model 5SA Single Arc Furnace).
The three electrodes, equally displaced around the top of the furnace, allow access access into the furnace along is central vertical axis for crystal pulling rods, splat rods, thermocouples, etc. Heating the specimen from the outside inward permits more even heating and maintains the specimen in a molten state longer.
This furnace consists of upper and lower water-cooled sections separated by a pyrex observation tube. The observation tubes serves as an insulator between the upper (negative) section, and the lower (positive) section. Power and water are fed to each of these sections by water-cooled power cables. Penetrating the top section are three copper stinger rods which carry tungsten electrodes. Each rod is mounted into a swivel ball which allows angular as well as vertical movement. The bottom section contains a tapered opening which accepts a variety of copper hearths. Provision is made for attaching a mechanical pump for evacuation prior to backfilling if this is desired. Ports are provided for inert gas inlet and outlet.
To use this furnace the work is placed in the cup of the hearth. The hearth is inserted into the tapered hole in the bottom of the furnace and clamped into position. The furnace is then purged either by a mechanical pump, followed by backfilling with inert gas such as argon or helium, or the unit is simply purged by a flow or inert gas. Once the system is purged and the desired power setting on the power supply is set the electrodes are brought to a position near the edge of material to be melted and an arc is struck. It is advisable to move the stingers around and over the specimen in order to obtain a uniform and homogeneous melt. The specimen is often turned over and remelted. A small, separate cup is provided in the base of the furnace for melting a small piece of titanium prior to melting the specimen, to remove any possible impurity from the furnace cavity.
Due to the nature of the arc technique, temperature in excess of 3500°C can be attained. Material such as molybdenum and tungsten are readily melted and nonconductors such as aluminum oxide, are melted by surrounding material by the arc plasma.
Operating Temperature Greater than 3500°C (6332°F)
Time to Temperature Instantaneous
Usable Hearth Diameter 1 5/8" Dia.
Furnace Size 8" Deep x 12" Wide x 17" High
Utility Requirements Electrical - 400 amps, 80/40 volts, D.C.
Water - 1 GPM @ 70°F and 50 PSI
Inert Gas - 1 to 5 CFH - Argon or Helium
Centorr/Vacuum Industries' manufacturing facilities have been repeatedly expanded and now include a group of integrated shops staffed and equipped for machining, metal forming, fabricating, electro-mechanical assembling, and operational testing of complete furnace and related processing systems. Centorr/Vacuum Industries' Applied Technology Center is staffed with a graduate ceramic engineer and technician. The lab is equipped with five high-temperature furnaces, and various metallographic support equipment to permit analysis and evaluation of a client's process requirements.