TUBULAR HEATERS

The most versatile of all electric heating elements, the tubular heater (calrod)  is capable of being formed into virtually any configuration. The basic design consists of a helical coil of nickel-chromium resistance wire precisely centered in a metal sheath. This coil is surrounded by magnesium oxide powder which is vibration loaded to insure even density throughout the length of the heater. This entire assembly is then reduced to the finished diameter, compacting the MgO and "freezing" the coil in the center of the heater. The range of ratings, sizes, materials and terminations available makes the tubular (calrod) heater adaptable to many industrial, commercial and scientific applications.

Copper Sheath: Water heating, water solutions non-corrosive to copper.

Steel Sheath: Immersion in oils, molten salt baths, alkaline cleaning solutions, tars and asphalt. Also suitable for clamping to metal surfaces and casting into aluminum.

Stainless Steel Sheath: Corrosive liquids, food processing equipment.

Incoloy Sheath: Air heating, radiant heating, cleaning and degreasing solutions, plating and pickling solutions, corrosive liquids.

Other sheath materials are also available for application considerations. Commonly specified are 316 stainless steel and Carpenter 20 stainless steel for corrosive immersion heating, copper clad steel for metal casting, Inconel for high temperature applications, and titanium for severely corrosive solution heating. Porcelain and ceramic coatings can also be provided for corrosive atmospheres in process air applications, immersion heating, or for other application considerations.

 

Minimum Unheated Section On Each End: 1-1/4" 11-1/2" to 50" 1-1/2" 51" to 80" 1-5/8" 81" to 110" 1-3/4" 111" to 140" 2" 141" to 170" 2-1/4" 171" to 192" 2-1/2" 193" and Longer	Sheath Material Max. Sheath Temperature Max. Watts Per. Sq. In. Copper 350°F/175°C 55 Steel 750°F/400°C 22 Stainless Steel 1200°F/650°C 30 Incoloy 1500°F/815°C 40

 

* Other diameters are available including metric sizes Tolerances and Limitations  Sheath Diameter ±.005* .210 .250 .312 .375 .430/.437 .475/.490 .625  Minimum Sheath Length 11-1/2 11-1/2 11-1/2 11-1/2 11-1/2 11-1/2 11-1/2  Maximum Sheath Length 144 144 420 480 420 312 250  Maximum Voltage 240 250 250 480 600 600 600  Maximum Amps 12 15 30 30 40 40 40  Minimum OHMS/inch of EHL .177 .100 .060 .040 .040 .040 .050  Maximum OHMS/inch of EHL 8 17 21 21 21 21 17  Wattage +5%   -10%  Resistance +10%   -5%  Sheath Length ±1/2%  Effective Heated Length ±1%

The following Standard Product PDF file is a list of standard length tubular heaters in various diameters and watt densities. The illustration shows Fig. 1 terminals, but any of the standard terminal figures are available. The sheath length is fully annealed for factory or field bending. The Incoloy sheath provides maximum corrosion and oxidation protection. The watt densities listed can be utilized in many air, liquid or solid heating applications and are U.L. recognized and C.S.A. certified components. CE testing and certification can be provided.
(PDF file - 327k)