Barrel Heaters - Hasmak.com.tr

W A T L O W<strong>Barrel</strong> <strong>Heaters</strong>Special Mica BandApplications andTechnical DataOperating FactorsUse as a low watt density rating as theapplication permits. A close match ofthe heat supplied to the actual requirementswill reduce temperature overshoot,reduce cycling and increase thelife of any band heater used.Calculate the safe maximum wattagefor the heater using:Heated Area x MaximumWatt DensityCalculate the heated area of the bandheater by subtracting the no-heat areafrom the total area in contact with thecylinder (3.14 x I.D. x width). Subtractthe no-heat area at the terminals(from table) and any additionalno-heat area caused by holes, slotsor oversize gaps.Determine the maximum watt densityof the heater from the graph on thispage. The curves are based onnarrow heaters mounted on a smooth,steel cylinder. Apply the necessarycorrection factors:• For heaters 57 mm (2.25 in.) to127 mm (5 in.) wide, multiply wattdensity by 0.8.• For high expansion cylinders(aluminum or brass), reduce thewatt density by 0.46 W/cm 2 (3 W/in 2 ).• For heaters 63.5 to 127 mm (2.25 in.to 5 in.) wide installed on a highexpansion cylinder, reduce wattdensity by a total of 0.46 W/cm 2(3 W/in 2 ) only.• For regular cylinder surfaces otherthan smooth, machined finish,reduce watt density by 0.46 W/cm 2(3 W/in 2 ).• For heaters that will be insulatedor enclosed, contact Watlow forspecific watt densities.No-Heat Area for Special Mica Band (Post Terminals)Heater SizeNo-Heat AreaHeater Diameter Width at TerminalsType mm (in.) mm (in.) mm (in.)One PieceTwo PieceCylinder Temperature—°F1100100090080070060050040030050.8 (Less than 2) 152.4 (Up to 6) 25.4 (1 x width)50.8 (2 or more)76.2 (3 or more)76.2 (Up to 3) 38.1 (1.5 x width)76.2 (More than 3) 25.4 (1 x width)76.2 (Up to 3) 76.2 (3 x width)76.2 (More than 3) 50.8 (2 x width)Maximum Allowable Watt DensityWatt Density—W/cm 22 4 6 8254 mm (10 in.) Dia.10020010 20 30 40 50 60Watt Density—W/in 276.2 mm (3 in.) Dia.500400300200Cylinder Temperature—°CInjection Molding<strong>Barrel</strong> <strong>Heaters</strong>29