PTC Finned Heaters
Posted by Adelle Webber on
PTC Finned Heaters for Industrial Applications
PTC finned, air, or convection heaters, contain ceramic disks that utilize positive temperature coefficient (PTC) technology that is safer, more efficient, and reliable than traditional electric resistance heating elements. The specially designed and manufactured ceramic disks are embedded in anodized aluminum fins to facilitate heat transfer by natural convection. The transfer of heat from the PTC ceramic heating element by natural convection of air is highly efficient and reduces circuit complexity.
It is essential to understand how the convection air will flow through or across the PTC heating component’s surface to choose the proper orientation. DBK USA experts can help you determine the best device for your application.
How do PTC heating elements work?
The most notable attribute of PTC convection heating elements is the positive temperature coefficient, which means that the component’s resistance is directly related to a change in temperature. Initially, the element’s resistance is low, allowing maximum current to flow through the device, creating heat. As the temperature increases, the resistance increases, decreasing the current flow. When the temperature reaches a designed limit, the resistance goes to infinity, and the current stops.
This characteristic in PTC heating elements and devices such as finned heaters provided several advantages when utilized correctly in an application.
- Rapid heating response
- Long life
- Low maintenance
Safety of PTC ceramic heating elements
There is a maximum temperature for every device using the element. This characteristic prevents overheating fires and damage to other components in the system.
The simplicity of PTC component circuitry
The characteristics of the PTC elements utilized for convection heaters require no temperature resistance control in the circuit. No additional components dramatically reduce the space and complexity of the heating circuit. Some applications may use other temperature sensing and control circuitry, such as medical devices requiring varying setpoint temperatures.
Rapid heating response
Applications that require rapid heating are ideal for PTC heating elements. The initial resistance close to zero allows maximum current flow for fast heat-up of the device. All electrical circuits require an interruptive switch or fuse. PTC circuits require slow blow fuses or contacts suitable for rapid current inrush.
Long life and low maintenance of PTC heaters
The PTC ceramic element, unlike the typical resistive wire element, does not deteriorate with time. Meantime to failure far exceeds other resistive elements. These quality aspects of the ceramic pieces also require almost no maintenance over the life of the device.
So why pair finned structures with PTC elements?
The convection assembly’s heat needs transfers to the surrounding air dictating the device’s location. The ceramic PTC element is bonded to the structure, facilitating heat radiation evenly across the anodized aluminum fins.
With the carefully designed structures, the heat is transferred from the aluminum surface, heating the passing air more effectively than the spot or surface heating design.
Finned air heating with aluminum fins is an effective method of transferring heat without fans’ additional power requirements or forced air. Check with our engineers to estimate the required air volume for your heating application.
How to select a PTC finned convection heater
Design engineers first consider what temperature will best suit the application to reduce moisture in a cabinet or keep components from freezing. Next may be consideration of available voltage and current availability. In some applications with limited space, the selection may begin with the device’s size and how someone will mount it in a cabinet. Finally, human safety and orientation of the components utilize the space, best efficiency, and safety.
Protection from hot finned heat exchangers
PTC air heaters transfer heat from the ceramic element to the aluminum fins and then into the surrounding or rising air. Those aluminum fins can be hot enough to cause injury if touched by human hands. Potential harm could be a primary consideration in selecting the fins of the heater guarded against human touch.
DBK USA’s Blizzard and Nimbus series of heaters have finger guards on select models.
The Nimbus series offers the finger guard on the highest power range 100 - 175 Watt heater.
These heaters are anodized aluminum extrusions that come with a 35 mm DIN attaching clip.
They also come prewired with silicon leads. The NG profile design is optimized for thermal convection and DIN clip, ready for mounting with an integrated terminal block.
See our video on the Nimbus series.
Currently, the Blizzard series provides the UL94V-0 high-temperature plastic housing on 20 - 65 watt heaters.
The Blizzard series heaters have a UL94V-0 high-temperature plastic housing. This touch-safe heater does not exceed 162 degrees F in the L version or 221 degrees F in the H version.
When touch guard safety is not required
DBK USA current Nimbus series of fin convection heaters 4 group selections from 30 to 240 watt without finger protection. When there is no need for this protection, there is a corresponding size saving enabling the heaters to fit into more confined spaces in a cabinet. See all four groups of Nimbus heaters here.
Other considerations when selecting the finned heaters
DBK USA PTC finned heaters can be DIN rail mounted. Depending on the heater’s size and if a finger guard is required, the heat exchangers will mount in different mounting rail orientations.
Some of the devices with finger guards mount in an edge orientation that reduces surface space and protrudes further into the cabinet.
The smaller Nimbus sizes can mount in either orientation on the rail as space permits. The largest Nimbus units can also be mounted in a flat orientation if ordered without the finger guard.
Some heaters have terminal blocks, while others are hardwired. Please allow for preferences when selecting any of the finned convection heaters.
Most of the heaters are 110-240 V AC/DC, but 12-24 Volt AC/DC are available by special order. Check with our experts on volume orders also.
Sizing a convection heating element
DBK USA has experts standing by to answer your questions. Design engineers can utilize the handing power calculator on our website. Feel free to call our thermal engineering specialists directly at 1-864-607-9047.
Go to our resources page for more information on PTC convection heaters.