Heater Catalog - Watlow

Tubular HeatersWATROD Double-Ended HeatersHigh-Temperature Tubular HeatersSheath Temperature Versus OvenTemperature at Various Watt DensitiesThis chart is used to verify the correct watt densityfor an oven application assuming no air flow. To usethe chart, first select the oven process temperatureon the X axis, using the chosen watt density read thesheath temperature rise above oven temperature fromthe Y axis. This number should then be added to oventemperature. If this number is greater than 1800°F(982°C), a lower watt density should be chosen.Sheath Temperature Rise Above Oven Temperature — °F8007006005004003002001001800°F Maximum Allowable Sheath Temperature(High-Temperature Tubular)0800 900 1000 1100 1200 1300 1400 1500 1600 1700Oven Temperature — °F30 WSI23 WSI16 WSI12 WSI8 WSIHeater Life Estimate ServiceWatlow now provides an industry first service with theoffering of the high-temperature tubular. By providingoperating parameters, Watlow provides customers withthe estimated life of the heater. To get this information,the following information should be provided:• Heater voltage• Heater wattage• Heater diameter (0.430 or 0.375 in.)• Heated length• Bend configuration and dimensions (number of bendsand radius)• Application including process temperature• Power switching device and cycle time (SCR, etc.)High-Temperature Heater ComparisonsWatlow MULTICELL Heater2200°FHigh-Temperature Tubular1800°FTypical Tubular Heater1600°F*Assuming normal design practices.88 WATLOW ®