Industrial Electric Air Heaters
Electric duct heaters are used for industrial, commercial, and residential applications by being placed in the airflow of HVAC ductwork to transfer heat into factory floors, offices, and homes to warm the air.
PTC heating elements are used in duct air heating systems.
Ceramic PTC, positive temperature coefficient, heating elements will not cause the ignition of dust or other combustible materials in the ductwork since they do not use resistive wires.
Finned structure for air heaters
The structure for transferring heat to the air flowing through the ductwork needs to cause a minimum pressure difference across the elements. While multiple types of fin structures are used the Delta fin provides the lowest pressure drop across the heater.
Duct heater temperatures
Depending on the application there are both high and low-temperature duct heaters available. Industrial process heaters often require high heat for a manufacturing operation requiring material heating. While space heating for offices or homes requires lower temperature heating elements.
What do duct air heaters look like?
Modern duct heaters are aluminum honeycomb or finned structures that fit either partially or completely across the inside of the square, rectangular, or round ductwork.
What typical features of PTC electric heaters?
PTC electric airflow heaters come in multiple sizes, voltages, and wattages. The dimensions of the ductwork and available voltage are primary factors. The output wattage and temperature requirements are taken into account.
What is differential pressure in the ductwork?
If you ever changed your home air conditioning or heating system filter it is because a dirty filter has a higher differential pressure than a clean one. Differential pressure is the resistance to airflow through a filter, heater, or cleaner placed in the air stream.
Air heaters' primary purpose is to heat the air in a specific space or area. The space to be heated could be an industrial process, air duct to a larger area, equipment cab, or interior of a house or car. The design of the duct or forced air heater is dependent on the specific application.
The design of this type of heater is a honeycomb or other fin-type structure that will transfer heat efficiently to the air being forced across the structure. Electric resistance heaters are embedded inside the fins or honeycomb structure that in turn transfers the heat to the air flowing through.
For process air heaters the fin or honeycomb structure made of aluminum or stainless steel typically will span the inside dimensions of the duct carrying the air to an area targeted for heating. This creates a very efficient & consistent heat transfer.
There is an extensive variety of heat exchangers arrangement for duct heaters including finned tubular, open coil, honeycomb, triangular, and straight fins. The configuration depends on the required airflow and each offers different heat transfer characteristics.
Heaters that are flexible in nature can be wrapped or formed and attached to surfaces to be heated. Conforming to the surface the flexible heating elements provide more contact surface area for efficient transfer of heat to the surfaces.
Electric car battery heating is becoming one of the major uses to flexible electric heaters. Solid-state batteries using metallic lithium anodes must be kept at an elevated temperature of 140 degrees F during charging.
The etched foil resistive element is very thin compared to wire resistive elements. For comparison, the aluminum foil used in everyday applications is from .0005 - .00025 inches in thickness. That thickness of foil or other alloy is etched chemically to provide the custom patterns used for a flexible heater.
What are electric 55-gallon drum heaters?
A 55-gallon steel drum is one of the most used containers for transporting and storing all kinds of materials, both liquid and granular. Electric 55-gallon drum heaters refer to types of heaters explicitly made for the size and diameter of the most common drum.
Plastic drums of the same size are taking the steel drum where there is an increased chance of corrosion due to the storage environment of the materials contained in the drums. A typical 55-gallon electrical heater will work on either steel, aluminum, or plastic drums with a few exceptions, such as the induction heaters.
Where are industrial drums used?
As the name industrial implies, 55-gallon drums are widely used in all types of industries for transporting and storing materials. The 55-gallon size originated with the transportation of oil from the first 2-inch pipeline in Pennsylvania.
The wooden drums were loaded onto horse-drawn wagons to reach their final destination. To this day, drums of oil are still used as a measurement in oil fields and transportation. But, of course, tankers carry oil in bulk rather than the 55-gallon drums, as do pipelines and trains.
Industrial locations far from these bulk transportation systems still use 55-gallon drums for smaller quantities of materials. Oil & lubricants aren’t the only products using drums or barrels. Food ingredients, syrups, additives, wine, and chemicals.
The drums make sturdy containers that can be sealed for the transportation and storage of any item poured from a drum, solid or liquid.
When is the drum heating used on steel drums?
Materials stored and transported in drums often need to be protected from freezing temperatures or be maintained at temperatures that keep them fluid. 55-gallon drums are difficult to heat uniformly for long periods.
Any material stored in drums outside or on a remote site in inclement weather use heaters to keep the materials from freezing. Or they are used to liquefy thick materials before pumping from the drums.
Industrial processes need to pump highly viscous materials like molasses or other ingredients utilize heaters to maintain specific temperatures inside the drums.
Why use an electric band heater?
Bottom heaters like a pot on a stove were one answer but required special handing equipment to lift the barrel for placement of the heater. If stored outside, the bottom of the drum could be sitting in the moisture of ice, making it even more difficult. If stored on a ship or in limited space, the bottom heaters aren’t practical.
Band heaters that could be easily attached and removable became a welcome answer.
What voltage is used for silicone electric heaters?
DBK USA heaters come in 120 - 220/240 voltages from 300W up to 1,500 watts. It is recommended that the heaters be disconnected from the power source when the container is empty or being filled. In addition, containers should be vented to avoid the build-up of internal pressure.
Are flexible band heaters better than a drum blanket?
Heating blankets are specifically designed to maintain a constant temperature with insulating properties. For certain products, a blanket may be preferred. There are multiple types of drum heaters available.
The blankets are clumsy to install and remove from a barrel or drum. Often there isn’t room to wrap the blanket around a drum easily, and they don’t heat the contents quickly.
A flexible band heater can be attached and removed easily. Multiple bands can heat the content of a drum quickly. Even when barrels are tightly stored, the silicone bands can be slipped over the barrel and fasten with spring fasteners on one site.
Do I need an adjustable thermostat with the heater?
Flexible silicone band heaters come with a built-in adjustable thermostat for controlling temperature. This prevents overheating or the requirement for other handling systems.
Just plug in the 6 to 9 foot 120V or 220V electrical cord, set the thermostat, and get back to work.
Why are flexible drum heaters made with silicone rubber?
Silicone rubber is durable, flexible, a good conductor of heat, and has high electrical insulation making it ideal for industrial applications. In addition, it is resistant to moisture and most chemicals. Although most band heaters are recommended for use in a dry indoor environment.
The electrical heating elements are embedded into the silicone in a pattern that allows for bending the band around a drum. Metal spring fasteners are attached to the ends of the bars for easy attachment.
Silicone also has a high-temperature tolerance. DBK HSSD drum heaters are built to IPX1 protection; class II double insulation, a 32-240 degree capillary thermostat, and an 80-inch power cable. Sizes include 5, 15, 30, and 55 gallons.
Can electric heaters be used in hazardous areas?
Need to know more about the silicone side drum heaters?
Talk to an industrial heating specialist about the best size and power rating for your application.
PTC stands for positive temperature coefficient. PTC means that the small ceramic heating element heats quickly but creates an increase in resistance as the temperature increases. This logarithmic relationship increases the resistance to a point where no current will flow as the heater reaches the maximum temperature.
The most common type of PTC heating element are small ceramic disks doped with quantities of other elements that create unique properties. Manufacturers have produced the same effect in conductive inks.
The set-point or maximum temperature is manufactured into the ceramic disk and remains
constant during the element’s life. Since the resistance is low when power is applied to the element, it heats quickly but shuts down as the temperature increases to the threshold. This makes the device self-regulating without the need for external controls.