does not by-pass round the edges of the trolley. Reference has been made to the 25min cycle from trolley entry in tunnel drying, and this cycle has to be maintained at all times. If, for example, there is a delay in tray loading due to lack of product from the blancher, or when the system is being run down, an empty trolley must be moved into the tunnel, or a series of empty trolleys, if necessary, so that the preceding loaded trolleys move in their proper sequence through the drying cycle Three Tunnel Dryer This dryer is a variation on the double tunnel system, and comprises two wet tunnels, with the dry tunnel running down the middle. Trolley entry is at the ends of the wet tunnels, and not by sideways loading as in the case of the double tunnel dryer. The fans and heaters are mounted on the top of the dryer, and the air stream is deflected downwards by louvres on to the trolleys in the first position. The air flow is parallel or concurrent with the trolley movement, and the interval of loading is usually reduced to 20min; each wet tunnel A and B accepting a trolley alternately at this time interval Thus, the product remains in the first position for 40min, before being moved into the second position by the second trolley On reaching the end of the wet tunnel, the trolleys again move alternately from A and B into the middle dry tunnel, thereby shortening the duration of travel in the latter, as here the trolleys resume the 20min cycle This system is equally as effective as the double tunnel but in making a choice of the type of dryer to install, the dehydrator must give full consideration to the labour content inherent in the quasi-continuous tray drying system, as against the completely continuous system offered by the Through Conveyor Band Dryer THROUGH-FLOW BATCH DRYERS The Buttner Favorit batch dryer has been used widely for many er in overseas factories for the drying of vegetables and fruits-especially where labour has been plentiful and cheap. It was used where small to intermediate levels of production were required It comprises a single drying chamber holding either 8 or 10 trays, 3m by 2m by 150mm deep. The trays are charged on an operating stand in front of the drying chamber. The tiltable tray lifting frame slides up and down between lateral tubular supports, with five arresting points controlled by limit switches, so that the progress of the electrically lifted trays can be pre- set A horizontal battery of heaters separates the trays in the drying chamber in two stacksdoes not by-pass round the edges of the trolley Reference has been made to the 25min cycle from trolley entry in tunnel drying, and this cycle has to be maintained at all times. If, for example, there is a delay in tray loading, due to lack of product from the blancher, or when the system is being run down, an empty trolley must be moved into the tunnel, or a series of empty trolleys, if necessary, so that the pding loaded trolleys move in their proper sequence through the drying cycle. Three 'hnnel Dryer This dryer is a variation on the double tunnel system, and comprises two wet tunnels, with the dry tunnel running down the middle. Trolley entry is at the ends of the wet tunnels, and not by sideways loading as in the case of the double tunnel dryer. The fans and heaters are mounted on the top of the dryer, and the air stream is deflected downwards by louvres on to the trolleys in the first position. The air flow is parallel or concurrent with the trolley movement, and the interval of loading is usually reduced to 20min; each wet tunnel A and B accepting a trolley alternately at this time interval. Thus, the product remains in the first position for 40min, before being moved into the second position by the second trolley On reaching the end of the wet tunnel, the trolleys again move alternately from Aand B into the middle dry tunnel, thereby shortening the duration of travel in the latter, as here the tmlleys resume the 20min cycle again. This system is equally as effective as the double tunnel but in making a choice of the type of dryer to install, the dehydrator must give full consideration to the labour content inherent in the quasi-continuous tray drying system, as against the completely continuous system offered by the Through Conveyor Band Dryer. THROUGH-FLOW BATCH DRYERS The Buttner 'Favorit' batch dryer has been used widely for many years in overseas factories for the drying of vegetables and fruits -especially where labour has been plentiful and cheap. It was used where small to intermediate levels of production were required. It comprises a single drying chamber holding either 8 or 10 trays, 3m by 2m by 150mm deep. The trays are charged on an operating stand in front of the drying chamber. The tiltable tray lifting frame slides up and down between lateral tubular supports, with five arresting points controlled by limit switches, so that the props of the electrically lifted trays can be pn?- set. A horizontal battery of heaters separates the trays in the drying chamber in two stacks. 69