Electric Heaters

IQS Newsroom Articles on Electric Heaters

About Electric Heaters and Electric Water Heaters Including: Air Heaters, Band Heaters, Cartridge Heaters, Ceramic Heaters, Coil Heaters, Duct Heaters, Immersion Heaters, Strip Heaters & Tubular Heaters.

Electric heaters encompass a broad category of heating elements and devices which are used in residential, commercial and industrial process applications. Technically speaking, an electric heater is any device which is powered by electricity and creates heat. Coil heaters, band heaters and strip heaters provide localized heat a to certain area within a machine to shape or melt materials, heat liquid tanks, radiate heat through the air or preserve the molten state of a substance. Ceramic heaters are a very common heating element used in space heaters, cartridge heaters, coil heaters, strip heaters and radiating air heaters used in residential or commercial settings. Immersion heaters and tubular heaters are used in liquid submersion heating applications, while tubular heaters and duct heaters are generally used to radiate heat into the air. Industrial processes such as plastic and metal extruding, hot stamping and industrial baking use strip heaters, cartridge heaters and band heaters to provide direct, localized or radiating heat. An electric heater may heat an object from room temperature up to over 1300°F.

Since heat is often an essential part of manufacturing processes, various types of industrial electric heaters must be designed and fabricated to precision wattages, temperature ranges and size/shape. In packaging, plastic fabricating, foam fabricating, metal fabricating and food processing industries, cartridge heaters are most often inserted through a custom-sized hole into the metal or material of equipment parts which require localized or high temperature heat. Extruding channels and hoppers use coil heaters, band heaters or strip heaters wrapped around or bolted to the channel to maintain the plasticity of the material being extruded. Radiating types of heaters such as duct heaters, immersion heaters and tubular heaters are used to heat liquid or air in water treatment facilities, residential applications, commercial buildings and many other applications.

Heating elements within electric heaters are mainly composed of three elements: an insulating core (typically ceramic), a heat conductive coil wrapped around the insulation and an encasing sheath made from stainless steel, aluminum, nickel or iron. Insulating cores are necessary in all types of electric heaters to retain and absorb electrical energy so that it might be released as heat energy by surrounding coils or materials. Ceramic is by far the most common type of insulation, although various electric heaters may use mineral, mica or fiberglass insulation, depending on the heater's application requirements. Radiating types of electric heaters transfer heat from ceramic cores or complete heating elements by moving heat through the air with fans, such as space heaters, or through hot air ductwork systems such as duct heaters.

When looking for an electric heater, it is important to identify its use. Applications for electric heaters such as space heating, melting or material shaping will require precision temperatures. Non-electric heating systems can involve coal, wood, gas or water, although most of these alternatives are far less energy-efficient than electric heat generation and are much more difficult to control. Cooking food products on an industrial scale using coil heaters built into equipment, for example, is far easier and more efficient than large scale cooking over a gas burner. Safety is another crucial concern when purchasing a heater. One must take into account how certain heaters react with certain substances. Some heaters are better than others when heating liquids or gases, or when heating small spaces. Safety features are often built into many electric heaters, such as auto shut-offs or warning signals.

Electric Heaters and Electric Water Heaters Image Provided by Watlow Electric Manufacturing Company	Electric Heaters and Electric Water Heaters Image Provided by Thermal Devices

Electric Heaters and Electric Water Heaters Image Provided by Hotwatt, Inc.

---

Electric Heater Types

• Air heaters use electricity to warm air.
• Band heaters are o-shaped heating devices that secure around an element. They can clamp around the outside of a cylindrical element and heat from the outside or clamp around the inside.
  
• Cartridge heaters are compact cylindrically shaped heaters which are used primarily for immersion applications. They also have a protective sleeve or sheath protecting the heating element from the immersion liquid.
  
• Cable heaters and coil heaters are formed from straight pieces of heating cable. These heating elements are formed into coils, spiral, sinuated, star wound or other patterns.
  
• Ceramic fiber heaters contain a layer of ceramic fiber insulation combined with a heating element. It is usually an industrial heater and available in cylindrical and flat configurations.
  
• Circulation heaters are used primarily to heat fluid streams in motion. Fluid runs through the heater, which increases the stream temperature; any liquid or gas is generally suitable for use with a circulation heater.
  
• Drum heaters are used to heat drums or their contents. Most drum heaters can accommodate various sizes of drums and many different substances.
  
• Duct heaters can heat moving gas streams and heat air as it moves through the heater. It is also sometimes used to intensely heat an object at the end of a stream of gas.
  
• Electric downflow heaters blow hot air down into the area needing heat and rapidly heat it to a desired level.
  
• Flexible heaters are devices that may be formed to fit a variety of items. Flexible heaters are made from pliable materials such as rubber or neoprene so they can be formed to fit a variety of circumstances.
  
• Foil heaters are made of flexible heater wire bonded to a thin aluminum substrate. The wire can be bended into a variety of shapes and act as the transport for the heat used.
  
• Immersion heaters are used when it is necessary to immerse a heater in the material being heated. Examples of such materials can be water or liquid polymers.
  
• Infrared heaters use a shield to reflect radiant heat onto a surface that is heated.  Types of infrared heaters include metal-sheathed tubular heaters, quartz tubes, quartz lamps, gas fired catalytic, flat-faced panels and ceramic emitters.
  
• Over-the-side heaters are the same as immersion heaters except that they hang over the side of a tank into the heated material.
  
• Radiant heaters diffuse energy heat rays in a 160 degree arc, and deliver heat evenly. They can maintain an almost uniform area temperature so that there is not more than 2 degrees variation in the space; many radiant heaters are so exact that heat can be directed to specific locations.
  
• Strip heaters are electric heaters that require minimal space.
• Thermoelectric heaters convert electric energy into heat. This is an irreversible conversion of electricity into heat; these heaters are often used for water and other fluids.
  
• Tubular Heaters are used to heat air, solids or liquids generally for custom heating purposes. These can sometimes be designed for mobile jobs in various fields.

---

Electric Heater Terms

Amps - The meter-kilogram-second unit of electric current that is equivalent to the steady current produced by one volt applied across a resistance of one ohm.
 
British Thermal Unit (BTU) - Used for measuring a quantity of heat. One BTU is the quantity of heat necessary to raise the temperature of 1 pound of water 1°F.
 
Celsius - The metric temperature scale in which water freezes at zero degrees and boils at 100 degrees, designated by the symbol "C".
 
Circuit - An electrical device providing a trail for electrical current to flow as found in electric heaters.
 
Duct - An enclosure in which air is moved that is primarily constructed from sheet metal.
 
Fahrenheit - The heat scale on which water freezes at 32 degrees and boils at 212 degrees, abbreviated by the letter F.
 
Fan - A device that creates currents of air, sometimes built in electric heaters to push air out from the unit.
 
Heating Coil - Any coiled element that serves as the source of heat. These heating coils are the main source of heat on electric heaters.
 
Heating Element - The component of the heater which is responsible for conducting the heat from electric heaters.
 
Hertz - In alternating current (AC electricity), the number of cycles per second, denoted Hz.
 
Peltier Modules - Jean Peltier in 1834, discovered that passing an electric current through the junction of two different conductors cools or heats the junction depending on the direction of the current. The modern Peltier modules are made out of semiconductor material, and are used in thermoelectric devices.  
 
Radiationange - The distribution of energy by electromagnetic waves, of a generally long wave-length.
 
Sensor - Any device that reacts to a change in the environment being measured, by signaling of the change via audible or visual means.
 
Therm - A measurement of heat equal to 100,000 BTU.
 
Thermocouple - Measures the difference in potential created at the junction of two different metal wires, which feed from the measuring instrument.
 
Thermostat - An automated device for controlling temperature on electric heaters.
 
Thyristor - A power semiconductor device with three terminals called the gate, cathode and anode. Its state becomes conductive (ON) or blocking (OFF) depending on the behavior of these terminals.
 
Volts - The difference of possibility between two points in a conducting wire with a constant current of one ampere.
 
Watts - The meter-kilogram-second unit of power equal to the power produced by a current of one ampere across a potential difference of one volt, 1/746 horsepower.