Barrel Heaters - Hasmak.com.tr

Temperature SensorsCase HistoriesGrommet StyleThermocouple ReplacesThermostat, ImprovesThermal PerformanceProblem:The extrusion coating and laminatingindustry demands dies that allow foraccurate temperature control andfast adjustment to reduce oreliminate the extruded edge beads,thus providing for material savingsassociated with traditional overcoatin the process.A Watlow customer manufacturedseveral sizes of laminating machinesthat included heated shoe or platendies. The dies were heated withcartridge heaters and the overalltemperature was controlled with acartridge style thermostat. Theheater and thermostat were installedin parallel 15.9 mm (0.625 in.)diameter holes located at the endsof the platen.The manufacturer wanted to achievemore precise platen temperaturecontrol. This necessitated replacingthe thermostat with a solid statetemperature controller andthermocouple temperature sensor.Solution:Watlow furnished a stock, ANSIType J "grommet" thermocouple toreplace the cartridge thermostat.The grommet thermocouple easilymounted with a small screw in thehole formerly used by the cartridgethermostat.The grommet thermocouple offeredeasy access for retrofit and allowedcontinuous use of the existing castplatens. This thermocouple becamethe universal sensor for severalstyles of laminating machines.Multipoint ThermocoupleSolves Sensing ReliabilityProblem:A plastics manufacturer <strong>com</strong>panyhad difficulty achieving itsproduction monitoring objective ofmeasuring the temperature gradientalong an extruder barrel's length.Their original design had severalflaws:• An excessively expensive and<strong>com</strong>plicated mechanical systemused to move a single sensorthrough the gradient• Sensor failure caused bymovement-induced fatigue• Reading inaccuracy caused bychanging the sensor's gradientalong its lengthSolution:Watlow vastly simplified the systemwhile improving reliability andaccuracy with a single, fixedmountedmultipoint sensorcontaining several sensor points.No modification was required on theextruder except removing the old,unreliable system.244