The blanched vegetables, racked on 50 trays per trolley, remained in the first position for 25min, then a second trolley was moved in, the pusher gear moving the first one to the second position in the tunnel. Thereafter, nd at the same 25min interval, further trolleys entered and all moved progressively down the wet tunnel, concurrently with the air flow At the end of the wet tunnel, each trolley emerged and, after turning through 180entered the dry tunnel. Here the trolleys met the air stream in counter flow, the hot air fan in the dry tunnel being positioned at the opposite end, ie, alongside the wet tunnel fan. The progression through the dry tunnel was at the same 25min interval, and the whole drying cycle varied from 6hr to 7hr, according to product and weight of tray loading. These dryers, in the main, were used for the dehydration of potatoes, cabbage and carrots for use by the services but after the War, many were used for a wide variety of vegetables for commercial distribution The inlet temperatures to the drying section of each tunnel of this typ are thermostatically controlled and typical operating temperatures for root vegetables are as follows: Wet Inlet:99°104℃ Dry Inlet:65°71℃ The wet tunnel outlet temperature will be in the range 57"-60C The air flow is controlled by louvres over the tunnels and it is possible to recycle 50-75 percent of the air, by louvre adjustment, before discharging it Recycling tends to slow down the drying cycle but this is usually done in the interests of economy and of restricting the demand on the fans The capacity of this type and size of dryer, when drying potato cubes or strips at 6kg tray loading, was of the order of 250kg of dry product per hour, according to the British Ministry of Food statistics over the period when these dryers were in general use in the UK for supplying the Services The wet tunnel fan had a rating of 1416cu m per min and the dry tunnel fan, 991cu m per min The construction of the tunnel walls uses engineering bricks with 28cm cavity external walls to lessen radiation losses. Both inlet and exit doors are of the counterbalanced lifting type, suitably insulated. Each tunnel has an overhead recirculation duct with louvres as previously described Access doors are provided in the fan chambers for servicing purposes The drying trays are ideally constructed of non corrosive metal angle with stainless bottom mesh, and the trolleys are of a size to fit neatly into the tunnel section, so that the air stream passes uniformly across the trays, andThe blanched vegetables, racked on 50 trays per trolley, remained in the first position for 25min, then a second trolley was moved in, the pusher gear moving the first one to the second position in the tunnel. Thereafter, and at the same 25min interval, further blleys entered and all moved pmgressively down the wet tunnel, concurrently with the air flow. At the end of the wet tunnel, each trolley emerged and, after turning through 180' entered the dry tunnel. Here the blleys met the air stream in counter flow, the hot air fan in the dry tunnel being positioned at the opposite end, ie, alongside the wet tunnel fan. The progression through the dry tunnel was at the same 25min interval, and the whole drying cycle varied fmm 6hr to 7hr, according to product and weight of tray loading. These dryers, in the main, were used for the dehydration of potatoes, cabbage and carrots for use by the Services but, after the War, many were used for a wide variety of vegetables for commefiial distribution. The inlet temperatures to the drying section of each tunnel of this type are thermostatically controlled and typical operating temperatures for root vegetables are as follows: Wet Inlet: 99' 104'C Dry Inlet: 65 o 71 "C The wet tunnel outlet temperature will be in the range 57" - 60'C. The air flow is controlled by louvres over the tunnels and it is possible to recycle 5@75 percent of the air, by louvre adjustment, before discharging it to atmosphere. Recycling tends to slow down the drying cycle but this is usually done in the interests of economy and of restricting the demand on the fans. The capacity of this type and size of dryer, when drying potato cubes or strips at 6kg tray loading, was of the order of 25okg of dry pduct per hour, according to the British Ministry of Food statistics over the period when these dryers were in general use in the UK for supplying the Services' nqukments. The wet tunnel fan had a rating of 1416cu m per min and the dry tunnel fan, 991cu m per min. The construction of the tunnel walls uses engineering bricks with 28cm cavity external walls to lessen radiation losses. Both inlet and exit doors are of the counterbalanced lifting type, suitably insulated. Each tunnel has an overhead recirculation duct with louvres as previously described. Access doors are provided in the fan chambers for servicing purposes. The drying trays are ideally constructed of non corrosive metal angle with stainless bottom mesh, and the trolleys are of a size to fit neatly into the tunnel section, so that the air stream passes uniformly across the trays, and 68