CONVEYOR BAND DRYERS- SINGLE PASS Reference has been made, in Chapter 2, to this type of dryer, and an ideal size unit for medium scale operation is a dryer 30-40m in length, with a conveyor width of 2.5-3m The conveyor band dryer is used in many industries outside food dehydration, and has been standard equipment in the textile, chemical and tobacco industries for many years. Lucerne and other silage is also dried by this method, and some of the first band dryers developed for food products owed much in their design to the experience the engineers had gained in The dryer normally has three heat zones, each of which is served by an individual fan drawing hot air from a common heat source. The latter can either be a seriesof steam batteries or a heat exchanger mounted on a coal or oil furnace. both indirect methods or the air stream can be from a direct source, such as gas or LPG The hot air stream is ducted underneath the interlocking perforated conveyor plates, which make up the continuous band, and the drying ai passes through the perforations in the plates, and thmugh the mass of product which is being conveyed at a controlled depth along the length of the dryer. The plates, running the full width of the band are about 23cm wide, and are made from perforated stainless steel plate. The perforations can be either 4mm round holes or 4mm squareones at 6. 4mm centres to give adequate open ama through which to pass the hot air stream. Air flow can alternate in an upward or downward direction as drying proceeds. The 23cm wide plates connect at either side with a 23cm pitch chain, which carries the band over the drive and free sprockets at either end of the Right: Continuous band dryer for vegetables with eloped by th company of ProctorCONVEYOR BAND DRYERS - SINGLE PASS Reference has been made, in Chapter 2, to this type of dryer, and an ideal size unit for medium scale operation is a dryer 30-40m in length, with a conveyor width of 2.5-3m. The conveyor band dryer is used in many industries outside food dehydration, and has been standard equipment in the textile, chemical and tobacco industries for many years. Lucerne and other silage is also dried by this method, and some of the first band dryers developed for food products owed much in their design to the experience the engineers had gained in grass drying. The dryer normally has three heat zones, each of which is served by an individual fan drawing hot air from a common heat source. The latter can either be a series of steam batteries or a heat exchanger mounted on a coal or oil furnace, both indirect methods, or the air stream can be from a direct source, such as gas or LPG. The hot air stream is ducted underneath the interlocking perforated conveyor plates, which make up the continuous band, and the drying air passes through the perforations in the plates, and thmugh the mass of product which is being conveyed at a controlled depth along the length of the dryer. The plates, running the full width of the band are about 23cm wide, and are made from perforated stainless steel plate. The perforations can be either 4mm round holes or 4mm square ones at 6.4mm centres to give adequate open ama through which to pass the hot air stream. Air flow can alternate in an upward or downward direction as drying proceeds. The 23cm wide plates connect at either side with a 23cm pitch chain, which carries the band over the drive and free sprockets at either end of the conveyor. Right: Continuous band dryer for vegetables with oscillating feed arrangement developed by the parent company of Proctor Dalgleish