Barrel Heaters - Hasmak.com.tr

Die andFormer <strong>Heaters</strong>THINBAND MicaBandApplications andTechnical DataOperating FactorsUse as low a watt density rating as yourapplication permits. A close match of theheat supplied to the actual requirementswill reduce temperature overshoot,reduce cycling and increase the life ofany band heater you use.Calculate the safe maximum wattagefor your heater using:Heated Area x Maximum Watt DensityCalculate the heated area of your barrelheater 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 (fromtable) and any additional no-heat areacaused by holes, slots or oversize gaps.Determine the maximum watt density ofyour heater from the graph on this page.The curves are based on narrow heatersmounted on a smooth, steel cylinder.Apply the necessary correction 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 the wattdensity by 0.46 W/cm 2 (3 W/in 2 ).• For heaters 57 mm to 127 mm wide(2.25 in. to 5 in.) 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, reducewatt density by 0.46 W/cm 2 (3 W/in 2 ).• For heaters that will be insulatedor enclosed, contact Watlow forspecific watt densities.• For units greater than 355 mm (14 in.)diameter, consult re<strong>com</strong>mendedclamping graph on page 39.• For units used in verticalapplications, consult factory forapplication assistance.No-Heat Area for THINBAND (All Terminations)Heater SizeNo-Heat AreaHeater Diameter Width at TerminalsType mm (in.) mm (in.) mm (in.)One Piece 63.5 (Less than 2.5) 177.8 (Up to 7) 25.4 (1) x widthTwo Piece 127 (5 or more) 76.2 (More than 3) 50.8 (2) x widthCylinder Temperature—°F11001000900800700600500400300Maximum Allowable Watt DensityWatt Density—W/cm 22 4 6 810020010 20 30 40 50 60Watt Density—W/in 238.1 mm (1.5 in.) Dia.76.2 mm (3 in.) Dia.500400300200Cylinder Temperature—°C234