Development of Batch Type Refractance Window (RW) Dryer for reduce drying time and cost

Abstract

The fourth generation, innovative technology refractance window (RW) dryer constructed to reduce drying time and cost of drying. The batch type refractance window dryer consists of hot water bath, electric heater, hot water pump, cold water bath, myler film or belt, SS roller pulleys, feed inlet hoper with motor, spreader roller, drying chamber hood, side view glass, air exhaust blower, main body, leg and lock type wheel, variable frequency drive, roller chain, Intel Pentium Processor, control panel, data logger with controller, temperature and humidity sensor, J-type thermocouple, contactor, DC drive, power adapter, MCB, scraper and product outlet tray with stand. The cost of batch type refractance window dryer machine was calculated as  2,35,574. Hot water bath made of stainless steel with dimensions 1000 mm 480 mm  100 mm having 48 liters water capacity. Two coil type single phase 1.50 kW capacity electric heater was inserted into the hot water bath to heat the water. The recirculating type pump of 0.50 hp capacity to recirculate the hot water in the hot water. The dimensions of myler film or belt were 3800 mm  440 mm  0.25 mm. Cold water bath (SS) dimensions 500 mm 480 mm  100 mm having 24 liters water capacity. The data logger attached in the control panel of RW dryer to monitor hot water temperature, product temperature, relative humidity of the drying chamber, cold-water temperature and thickness of the material. Doctor blade or scraper 475 mm  100 mm  12 mm used to collect the dried product. The drying time and power consumption was observed 55 minutes and 1.50 kWh for drying carrot puree of 2 mm bed thickness and 85 °C hot water temperature. And the thermal efficiency and overall system efficiency of refractance window dryer was observed 78.78 % and 45.24 % respectively.