The radiator of the BB 1200 comprises a heat pipe made of two coaxial stainless steel cylinders. The inner cylinder serves as a radiating cavity and the outer one - as a casing of the heat pipe. A gap between the cylinders filled with a capillary structure made of nickel grid and a heat-transport medium. It is evacuated and hermetically sealed off. Sodium serves as a heat-transport medium. When heating the outer casing of the heat pipe, sodium is evaporating and transporting heat as hidden heat of vaporization to the walls of the radiating cavity where it condenses. Then the condensed metal comes back to the evaporation zone through the capillary structure, and cycles round loop repeatedly.

The melting temperature of the heat-transport medium sets a lower bound on operating temperature range, and the upper bound of it is restricted by the alarm vapor pressure in the heat pipe.
The heat tube outer casing directly contacts a heater. The heater is made from KANTHAL AF-type wire with 0.8-mm diameter and is assembled inside a stainless steel casing. The heater is surrounded by a thermal insulation. A specific spring-loaded device compensates for heat expansion of the radiator.
The BB-1200 is supplied with a Pt-PtRh thermocouple, which is mounted on the side of the rear flange of the chamber and is inserted into the specially designed hole in the heat pipe. Electric power supply terminals are located on the rear flange.

Delivery Set

Sodium Heat Pipe Blackbody Source BB 1 200
Temperature Control System with Pt/PtRho Thermocouple, PID controller and Software Power Supply
Technical Passport with the Temperature Sensors Certificate, Principal Electrical Connections Diagram, System Testing Results

References

1) V.I.Sapritsky, B.B.Khlevnoy, V.B.Khromchenko, B.E.Lisiansky, S.N.Mekhontsev, U.A.Melenevsky, S.P.Morozova, A.V.Prokhorov, L.N.Samoilov, V.I.Shapoval, K.A.Sudarev, M.F.Zelener. Precision blackbody sources for radiometric standards -Applied Optics, 1997, v. 36, pp. 5403-5408
2) Sapritsky V.I., Khlevnoy B.B., Khromchenko V.B., Lisiansky B.E., Mekhontsev S.N., Morozova S.P, Shapoval V.I., Samoilov L.N., Zelener M.F., Prokhorov A.V. Precision blackbody sources for radiometry and radiation thermometry – TEMPBEIJING ’97. Proc. of the Int. Conf. on the Temperature and Thermal Measurement. Beijing, China, October 6-10, 1997, pp. 141-146
3) Sapritsky V.I., Khlevnoy B.B., Khromchenko V.B., Lisiansky B.E., Mekhontsev S.N., Morozova S.P., Shapoval V.I., Samoilov L.N., Prokhorov A.V., Zelener M.F. Precision blackbody sources for thermometry and radiometry. – 6 th International Symposium on Temperature and Thermal Measurement in Industry and Science (TEMPMEKO’96). Torino, Italy, 10-12, September, 1996, pp. 321-326