Finned tubular heaters are custom-made to fit your application, and are designed for applications where tubular heaters are exposed to forced convection. Placing fins around tubular heaters increases their surface area and improves heat transferring capacity. Finned tubular heaters, compared to regular tubular heaters, run at lower surface temperatures for the same watt densities when placed in identical air streams. Finned tubular heaters are built to order due to individual application requirement
Applications
Dryers
Recirculation ovens
Fan-forced heaters
Heat treating and annealing
Graph 1 compares watt density, outlet air temperature, and the speed of air flow for regular and finned tubular heaters. Finned tubular heaters are not recommended for applications where outlet air temperatures exceed 600°F.
Construction
The sheath material of a finned tubular heater and its watt density are critical factors that affect its durability. The standard finned tubular heaters are made of steel sheath and steel fins (750°F maximum surface temperature) since steel is very efficient in heat transfer. Finned tubular heaters have a plain-surface finish. For corrosive environments or high-temperature applications (above 750°F), finned tubular heaters can be made with stainless steel sheath and stainless steel fins.
Watt densities
Safe watt densities that keep surface temperatures below allowable limits depend on the speed of the incoming air and its outlet temperature.
Graph 2 shows maximum watt densities recommended for a specific sheath temperature and air velocity.
Physical characteristics
The outside diameter of fins, their thickness, the spacing between consecutive fins, and the element sheath and fin material all play a major role in the effectiveness of heat transfer.
Tube diam. | Fin thickness | Fins per inch | Fin width | Total in² per linear inch* | Max. sheath length* | Outside diam. of fins |
0.216' | 0.020' | 5 | 0.375' | 8.30' | 240' | 1.01' |
0.315' | 5 | 9.20' | 1.07' |
0.375' | 5 | 10.10' | 1.13' |
0.430' | 5 | 10.83' | 1.18' |
0.475' | 5 | 11.60' | 1.23' |
*Dimensions are subject to change |
Kilowattage needed to heat air
Optional features
Rustproof coating
Stainless steel fins and tubular sheath material
Nickel plating
Special mounting accessories
Various shapes
Mounting attachments
Threaded fittings, if required, are the standard mounting attachments supplied with finned tubular heaters. These fittings are brazed or crimped onto the heaters. For special applications, finned tubular heaters can be made with mounting brackets that have special designs.
To order finned tubular heaters, please specify...
Element diameter and sheath material
Fin material
Terminal type
Total sheath length
Cold section at each end
Voltage and wattage
Bending configuration drawings
Quantity
Mounting characteristics and accessories (if required), and
Special moisture-resistant seal (if required).