Barrel Heaters - Hasmak.com.tr

W A T L O WHot RunnerNozzle <strong>Heaters</strong>Metric FIRERODCartridgeMaximum AllowableWatt DensityContinuedHeating Steam, Air and GasesAmbient Temperature—°CFIREROD Sheath Temperature—°C8006004002000120010008006004002000Maximum Watt Densityvs. Ambient Air Temperature0 2 4 6 8Watt Density—W/cm 2Sheath Temperature in 20°C (70°F)Ambient AirNot Pre-OxidizedPre-Oxidized2 4 6 8Watt Density—W/cm 2Watt Density vs. Ambient AirThe Watt Density vs. Ambient AirTemperature graph shows themaximum allowable watt densitywhen one metric FIREROD heateris operated in air or similar gas.For metric FIRERODs grouped ina single row, with no less than onediameter between elements, multiplyvalue from graph by 0.95. When areflector is placed behind theheaters, multiply the maximumallowable watt density value fromthe graph by 0.85.Sheath Temperature inAmbient AirThe Sheath Temperature inAmbient Air graph indicates thewatt density required to bring ametric FIREROD heater to a givensheath temperature when operatedin 20°C (70°F) ambient air.At 7 W/cm 2 (44 W/in 2 ), the sheathtemperature would be 790°C(1450°F). At this temperature,one year life would be expected,provided that cycling is not toofrequent. Higher temperatureswould result in reduced heater life.Injection MoldingHot Runner Nozzle <strong>Heaters</strong>Air Velocity Past Heater—m/sec22.520.517.515.012.510.07.55.02.5Maximum Watt Densityin Moving AirEntering Airup to 95°C (203°F)FIREROD—Parallel to Air FlowFIREROD—Perpendicular to Air FlowWatt Density in Moving AirThe Watt Density in Moving Airgraph gives the maximum allowablewatt density of a metric FIRERODheater in moving air.If the volumetric flow rate of air isknown in m 3 /s (or CFM), divide thisvalue by the net free area in m 2(or ft 2 ) around the heater todetermine air flow velocity. The netfree area is the total area of theenclosure minus the area occupiedby the heater.5 10 15Watt Density—W/cm 220105