Highly versatile and economical Durex tubular heater elements are applied in virtually every conceivable type of heating application. They can be applied straight or bent into complex formations. They can be reliably applied to heat a multitude of liquids, gases, and solids. Tubular heaters are also used for radiant heating in open air or in vacuum atmospheres. They can be cast into, or clamped on to, metal to form heated parts. Durex Industries’ application and design engineering team are available to assist in specifying the proper heater configuration.
Contact us for Engineering Assistance.
Heating Metal Parts
Durex recommends to “press fit” the tubular element into milled groove plates for extended heater life. Ensure that all heated portions of the heater are in contact with the part. Heat transfer cement should be used to promote heat transfer. If clamps are used, they should be closely spaced and not over tightened to ensure good heater-to-part contact. Allow for up to 10% length increase due to thermal expansion during heating.
Tubular elements are typically formed into ‘U’ (hairpins) or loop type formations and either placed over the tank side or secured through a hole in the side (or bottom) of the tank. Factory installed fittings or field installed compression fittings are used to mount and seal the tubular element against the tank wall. Refer to the Immersion, Circulation and Over-The-Side Heater section of our website for other liquid heating products.
To prevent overheating or fouling the heater element, ensure the heated portion of the tubular heater is immersed in liquid at all times. For optimal results, properly match the sheath material and heater watt density to the liquid application. Refer to the chart below for general sheath material and watt density guidelines.
Heating Air & Gases
Durex tubular heaters are robust solutions for furnace and oven heating as well as forced air and gas heating applications. Refer to the Circulation and Duct Heater sections of our website for forced air and gas heating products. Tubular elements are typically formed into ‘U’ (hairpins) or one of the multiple bend formations. They are installed through wall openings and secured with lock washers, clips, threaded fittings or mounting bracket.
For optimal results, use an Incoloy® sheath and ensure reasonable watt densities are used. Allow for 10% length increase due to thermal expansion. For horizontal installations, provide supports at least every 18” of length to avoid element sagging due to high temperatures.
Radiant Heating and Vacuums
Tubular heaters used for radiant heating typically use reflectors to direct heat energy toward the part being heated. However, in a vacuum, heater elements operate at much higher temperatures. Therefore, reduce watt density by 20% to 30% versus air heating conditions to ensure good heater life. Aluminum sheath as well as Inconel® sheathed heaters are typically used with vacuum feed through assemblies. Vacuum leakage rates can be measured down to 8x10-8 SCCS He (3x10-6 Pa l/s).
Send your technical questions directly to our engineering team and get answers within hours, not days.Ask Now
Get the insight and advice you need for your Tubular Heating Elements application