Tubular Heaters www.tempco.com | (800) 323-6859 | email: [email protected] 10-3 Sheath Length Heated Length Minimum Unheated Length Length Tolerance (±) Tolerance (±) Each End in mm in mm in mm in mm 11-20 279-508 3/32 2.4 1/4 6 1 25 20-50 508-1270 1/8 3.2 1/2 13 1-1/4 32 50-80 1270-2032 5/32 4.0 7/8 22 1-1/2 38 80-110 2032-2794 3/16 4.8 1-1/8 29 1-5/8 42 110-140 2794-3556 7/32 5.6 1-3/8 35 1-3/4 44 140-170 3556-4318 1/4 6.4 1-5/8 41 2 51 170-200 4318-5080 3/8 9.5 1-7/8 48 2-1/4 57 200-up 5080-up 1/2 12.7 2-3/8 60 2-1/2 64 Element Resistance in Ohms Sheath Length Diameter Maximum Maximum per Heated Inch min. max. in mm Voltage Amperage min max in mm in mm .260 6.6 250 15 .100 17 11 279 200 5080 .315 8.0 480 30 .060 21 11 279 200 5080 .375 9.5 600 30 .040 21 11 279 200 5080 .430 10.9 600 40 .040 21 11 279 255 6477 .475 12.1 600 40 .040 21 11 279 255 6477 .625 15.9 600 40 .040 17 11 279 255 6477 Electrical Limitations and Minimum/Maximum Sheath Lengths Table 1 Sheath and Heated Length Tolerance (applicable for all diameters) Table 2 Tubular Heater Standard Specifications Maximum Sheath Temperature refers to the maximum temperature of the element sheath material. Consideration must be given to the maximum temperature that can be safely applied to the heated material. See Watt Density on the previous page for additional information. Incoloy® 840: Nickel 18-20%, Chromium 18-22%, Iron balance. Has about 10% less nickel than Incoloy 800. Used in many air heating applications, where it has exhibited superior oxidation resistance at less cost than Incoloy 800. Maximum Sheath Temperature: 1600°F / 871°C Incoloy® 800: Nickel 30-35%, Chromium 19-23%, Iron balance. The high nickel content of this alloy contributes to its resistance to scaling and corrosion. Used in air heating and immersion heating of potable water and other liquids. Maximum Sheath Temperature: 1600°F / 871°C 316 Stainless Steel: Chromium 16-18%, Nickel 11-14%, Iron balance. Modified with the addition of Molybdenum (2-3%) to improve corrosion resistance in certain environments, especially those which would tend to cause pitting due to the presence of chlorides. Applications include deionized water. Maximum Sheath Temperature: 1200°F / 649°C 304 Stainless Steel: Chromium 18-20%, Nickel 8-11%, Iron balance. Used in the food industry, medical, and chemical heating. Maximum Sheath Temperature: 1200°F / 649°C 321 Stainless Steel: Chromium 17-20%, Nickel 9-13%, Iron balance. Modified with the addition of Titanium to prevent carbide precipitation and resulting intergranular corrosion that can take place in certain mediums when operating in the 800-1200°F (427-649°C) temperature range. Maximum Sheath Temperature: 1200°F / 649°C Copper: Standard Copper Alloy A low temperature, inexpensive material used mainly for clean water heating. Maximum Sheath Temperature: 350°F / 177°C Steel: Low Carbon Used for high to low viscosity oils, asphalt, tar, wax, molten salt, heat transfer liquid media and other compatible solutions. Maximum Sheath Temperature: 750°F / 399°C Other Sheath Materials: Available for a limited number of diameters. Consult Tempco for more information. Inconel® 600: Iron 6-10%, Chromium 14-17%, Nickel balance Maximum Sheath Temperature: 1800°F / 982°C Incoloy® 825: Nickel 38-46%, Chromium 19.5-23.5%, Molybdenum 2.5-3.5%, Iron balance Maximum Sheath Temperature: 1100°F / 593°C Tubular Heater Standard Sheath Materials The selection of a sheath material should be made based on the chemical composition of the gas or liquid being heated, the characteristics of the materials entering the solution, and the processes controls. A material selection guide can be found on page 16-12. The following are the most common tubular element sheath materials. For other materials consult Tempco. NOTE: The best source for chemical/sheath compatibility is the supplier of the gas or liquid to be heated.
