NovaTec NovaWheel NWB- DC+ Series User Manual
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Contents
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1211.0 PRINCIPLE OF OPERATIONThe NWB-DC+ Series is designed to convey moistureladen resin from a source container, dry it, and deliver itto the throat of a process machine.11.1 Resin DryingThe NWB-DC and DC+ NovaWheel Series dryers wasengineered and designed to effectively remove moisture(in the vapor state) from hygroscopic plastic resins. Thisprocess is accomplished by the continuously rotatingdesiccant wheel and the three air streams (Process, Purgeand Regeneration). The Process return air is exposedto an adsorbing media (desiccant wheel) in a sealed airstream, where the desiccant adsorbs the moisture fromprocess air. After the desiccant has adsorbed the mois-ture, it is exposed to a Regeneration air stream whichhas been pre-heated to a temperature of about 380°F.(190°C). This causes the moisture to be driven out fromthe desiccant and prepares it for more moisture adsorp-tion. Now the desiccant media passes through third airstream called purge air stream. Here the desiccant mediais cooled down by some of the process air before en-tering back into the process to provide for better per-formance. The three air streams (process, regenerationand purge) are separated by special Teflon fabric coatedsilicon seals. The process air and regeneration air is com-pressed by using regenerative blowers.The dry air from the dryer is then heated to the desireddrying temperature by an electric heater located in thedryer cabinet. The hot dry air enters the hopper at thebottom and removes moisture vapor from the resin in thehopper. The air from the top of the hopper is returnedto the dryer, where it is filtered, passed through thedesiccant wheel to remove moisture from the air streamand cooled before the process blower sends the air backthrough the heater and into the bottom of the hopperagain in a continuous process.11.2 Resin ConveyingA regenerative blower pulls resin from a bulk containerthrough a pickup wand and flexible hose to an appro-priately-sized vacuum receiver where the material is fedinto the drying hopper, as needed. As the material passesthrough the drying hopper it is metered through a vac-uum takeoff valve to a machine mount vacuum receivermounted on the process machine, thereby maintaining aconstant flow of dry material to the feed throat.11.3 System Flow Diagram12.0 SPECIFICATIONS – NWB-DC+ DRYCONVEY SERIESProcess Air dew Point (nominal): -40ºF (-40°C)Drying Temperature: 150-350°F (66-177°C)Air and Material Hose Diameter: 1.5” ID (40 mm)Compressed Air Fittings for Hopper Receiverswith Blowback:VR-5-B: 3/8” FNPT, VR-12-B: ¼” FNPTCompressed Air requirements for Blowback:80-120 psi (5.5-8.3 Bar)*Based on material bulk density of 38 lb./ft.3Model NWB-DC & DC+ -25 -50 -75 -100 -150 -200 -300*Max material Flow (lbs./Hr./Kg/hr) 25/11.4 50/22.7 75/34 100/45.4 150/68.2 200/92 300/136Voltage—Phase -Hz 460-3-60Hopper Receiver VR-5 VR-5 VR-12 VR-12 VR-12 VR-12 VR-12Machine Mount Receiver VR-5MM VR-5MM VR-5MM VR-5MM VR-5MM VR-5MM VR-5MMWheel Speed—Nominal RPH (rev/hr.) 10 10 10 10 10 10 10Water Inlet/Outlet Connections 3/8” 3/8” 3/8” 3/8” 3/8” 3/8” 1/2”Flow Rate—GPM gal/min. 0.25 0.5 0.75 1.0 1.5 3.0 3.0 |
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