From Chromalox

The viscosity of oils and hydrocarbons varies
widely with type and temperature. Since highly
viscous liquids transfer heat poorly, sheath
watt densities and operating temperatures are
critical in oil heating applications. As a general
rule, regular oil heaters rated 20-23 W/in2 are
recommended for heating light weight oils
(SAE 10 to SAE 30). For medium weight oils
(gear oils, etc.), 12-15 W/in2 are suggested.
Bunker C, tar, asphalt and other highly viscous
oils may require 6-8 W/in2 or less to prevent
carbonization, particularly if not under fl owing
conditions. Some oils may have additives
that will boil off or carbonize at very low watt
densities. When oils of this type are encountered,
a watt density test is recommended to
determine a satisfactory watt density. The following
charts provide guidance and suggested
watt densities for various oils.

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Products & Services
Duct Heaters
Duct heaters are used to heat moving gas streams.
Tubular Heaters
Tubular heaters are generally used in custom heating applications. Base (tubular) heating elements can be bent into standard or custom shapes.
Air Heaters
Air heaters are devices used to heat air.  They include forced air products as well as all types of radiant and space heaters.
Radiant Heater Elements
Radiant heater elements are used with radiant flat panel and radiant reflective heaters.

Product Announcements
CCI Thermal Technologies Inc. - Caloritech™ FPH Flange Pipe Insert
The Caloritech™ FPH Flanged Pipe Insert Heater (also known as an insert tank heater) provides a safe, cost-effective low maintenance solution for tank heating. By enclosing the heating elements... (read more)
Chromalox - Custom Cartridge Heaters
Cartridge heaters are high efficiency heating elements. Diameters of cartridge heaters range from .25"to 1.25". Watt densities from 25 W/in2 to 200 W/in2 and sheath temperatures to 1600°F. Optional... (read more)
Hotwatt, Inc. - DIRECT IMMERSION 55 GALLON DRUM HEATER
Designed for direct immersion thru 2" bung opening in 55 gallon drums. (read more)
Hotwatt, Inc. - Superwatt Cartridge Heater, High Watt Density
Applications: Dies, Heat Sealing, Hot Melt Adhesive, Plastic Molding, Platens and Shoe Machinery. Elements are designed for maximum: Watt density, temperature, heat transfer, and heater life. (read more)
Hotwatt, Inc. - Heaters for OEM, Medical, Commercial & Military
Hotwatt, made in USA, began with open coil heating elements and now includeds: cartridge, air process, immersion, strip and finned strip, tubular and finned tubular, band, foil, flexible... (read more)
Hotwatt, Inc. - Electric Heating Elements, Customized and Stock
Hotwatt, made in USA for 60+ years, manufactures electric heaters including cartridge, air process, immersion, strip and finned strip, tubular and finned tubular, band, crankcase, foil, flexible... (read more)

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Ferro Techniek is highly specialised in making heaters based on PEMS technology: Thick Film Heaters. A thickfilm heating element consists of several layers. Benefits of Thick Film Heaters - Thin, fl...