What Are External Electric Tank Heaters?

External Electric Tank Heaters: Eliminate Concerns about Material Compatibility and High Watt Densities when Dealing with Viscous, Aggressive, or Erosive Contents

Many industries use large fiberglass or steel tanks that need to be heated. A common way to heat the tank contents is with electric heating elements designed to penetrate the tank through an existing flanged or threaded opening. This type of heating element, known as an immersion heater, is put directly in to the process media and heats the tank contents. While this heating method is efficient, it's not alway practical. Some tanks contain very viscous, chemically aggressive, or physically erosive media. Using an immersion heater for these applications gets tricky. Very careful consideration needs to be taken when determining proper watt density, maximum sheath temperatures, and material compatibility.

Another way to electrically heat steel or fiberglass tanks is with externally mounted "pad" heaters, also known as heater panels. This type of heating element is mounted directly to the exterior tank surface and provides evenly distributed heating over a large area of the tank. These heaters are designed to deliver the required amount of energy (watts) distributed over a larger surface area, and provide "gentle" heating that will not burn or react with the process media. Furthermore, since heating panels are mounted externally, there's no concern with corrosion or erosion from aggressive or abrasive contents.

External electric panel heaters are constructed of flat foil based heating elements or nichrome resistance wire patterns sandwiched between flexible and tough silicone or fiberglass layers. Because of the heating element pattern, even distribution of heat is assured with no hot spots. Panel heaters come in many standard sizes, volts and wattages. Custom shape and sizes are available too for tanks with complex geometries. Installation is easy and requires no special tools or skills.  Heaters are usually installed by banding them to the tank with metal bands or polyester straps, which takes only a matter of minutes.

For optimal performance and greatest energy savings, external panel heaters should be insulated to minimize backside loses.  The job of the insulation is to direct the majority of the heating panels energy into the tank. Failure to insulate allows for heat energy to escape to the surrounding area.

For tank heating applications where immersion heater sheath temperatures, or sheath material compatibility is a concern, or where penetrating the tank is impractical, externally mounted electric heating panels are an excellent solutions.

Industrial Process Heating: Electric and Fuel Based

Electric heater used on industrial hopper throat.

Process heating operations supply thermal energy to transform materials like metal, plastic, rubber, limestone (cement), glass, ceramics, and biomass into a wide variety of industrial and consumer products. Industrial heating processes include drying, heat treating, curing and forming, calcining, smelting, and other operations. Examples of process heating systems include furnaces, ovens, dryers, heaters, and kilns. Many of these systems are mature technologies used ubiquitously throughout manufacturing. Process heating is used to raise or maintain the temperature of substances involved in the manufacturing process, such as the use of heat to melt scrap in electric arc furnaces to make steel, to separate components of crude oil in petroleum refining, to dry paint in automobile manufacturing, or to process food for packaging.

Electricity-based process heating systems transform materials through direct and indirect processes. For example, electric current is applied directly to suitable materials to achieve direct resistance heating; alternatively, high-frequency energy can be inductively coupled to suitable materials to achieve indirect heating. Electricity-based process heating systems are used for heating, drying, curing, melting, and forming. Examples of electricity-based process heating technologies include electric arc furnace technology, infrared radiation, induction heating, radio frequency drying, laser heating, and microwave processing.

Gas burners for process heating.

Fuel-based process heating systems generate heat by combusting solid, liquid, or gaseous fuels, then transferring the heat directly or indirectly to the material. Hot combustion gases are either placed in direct contact with the material (i.e., direct heating via convection) or routed through radiant burner tubes or panels that rely on radiant heat transfer to keep the gases separate from the material (i.e., indirect heating). Examples of fuel-based process heating equipment include furnaces, ovens, kilns, melters, and high-temperature generators.

For information on any industrial heating application, contact Hotfoil-EHS at 609.588.0900 or visit http://www.hotfoilehs.com.

Electric Process Heaters & Controls

Hotfoil specializes in electric surface heating systems for fly ash hoppers on electrostatic precipitators or baghouses, coal and material handling systems, tanks, pipes, etc. in all types of industry.

For more information, visit http://www.hotfoilehs.com or call 609.588.0900.

New Hotfoil-EHS Catalog Available for Download

Electric Heating Systems, Inc. (EHS), established in 1994 in Robbinsville, NJ, is a designer and supplier of turnkey, permanent low temperature heating systems for the electric power and tank fabricating industries. Later, this division's name was changed to Hotfoil, and the EHS division began manufacturing ceramic mat (pad) heaters, power consoles, and accessories for the heat treating industry.

Hotfoil-EHS is now a major manufacturer and producer of standard and custom designed industrial heat treating products with an exhaustive inventory including custom control panels, heat treating power consoles, cables and splitters, temperature recorders, thermocouple attachment units and pin guns.

You can download the latest product catalog here.

Use External Electric Heating Panels for Ease and Simplicity

ELP tank heater construction

When it comes to heating process tanks electrically, you have two options - immersion or externally mounted panels. Immersion heaters must penetrate the tank wall, or be placed of over-the-side in an open top tank. Both approaches add cost and/or safety considerations. Sometimes entry to the tank may not be possible at all.  A good alternative are electric heating panels.

One type of exterior heater design, the epoxy laminated panel (or ELP), is a very versatile tank heater. Possessing unique flexibility, ELP heating panels can be used in a variety of heating applications ranging from freeze protection to process heating up to 212 deg. F . These panels can be used on either vertical or horizontal tanks of metallic or non-metallic construction. They can be used in dry, wet, or corrosive environments in ordinary or approved hazardous locations.

ELP heating panels are quick and easy to install, require no special tools or skills. Heaters are usually installed by banding them to the tank with metal bands or polyester straps. Installation of several ELP heating panels takes only a few minutes.

Check out the following document for more information on the epoxy laminated panel heaters.

Epoxy Laminated Tank Heater Panels from Hotfoil EHS, Inc.