ND D G dD kn x st c Shaft seals see page onwa B3-DH11-B Bevel-helical speed reducers B3

Flender/Flender Gear Units/Bevel-helical speed reducers B3

ration recommends different conguration for the air delivery duct (.Rather than having air spill down the side walls along the full length of the air delivery duct, it recommends discharging the air at three different positions along the ceiling: 2%should be discharged near the front of the vehicle, 5% at approximately one-third (1/of its length (from the front to the rear), and 3% at three-quarters (3/ of its length. This duct conguration also ensures that air will spill down the side walls along the full length of the vehicle. Different oor duct designs are used in semitrailers. The oor conguration affects the amount of air that circulates underneath the cargo and therefore affects the capacityto absorb the heat conducted through the oor. The most common types of oors foundin transport trailers and railcars are the duct board oor and the -beam oor. Ashby ( states that about 0.1 2(2 in of return air passage is required for the average trailer blower to operate at full capacity. However, the average duct board oor offersonly approximately 0.0 2of return air passage. The average -beam oor offers approximately 0.1 m2of return air passage, which is much better than that of the duct board oor. Nevertheless, the -beam oor is found to be less resistant to physical damageduring loading and unloading operations. Placing produce on pallets signicantly increasesthe area available for air circulation and should therefore be considered for trailers with duct board oors. For trailers that are not equipped with duct oor, produce must be palletized to ensure sufcient air passage. The use of return air bulkhead is highly recommended in semitrailers because it helps to isolate the load from the front wall and prevents the load from blocking the returnairports of the refrigeration unit (Kasmire et al., . Both frame bulkhead and solidbulkhead are commonly used. The frame bulkhead prevents the blockage of the return airports but does not prevent the short-circuiting