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with fold-up lining
• Two plastic bags, known as Dynaframs, are used for lining the Dynabulk bulk road tanks produced by R. Murfitt Ltd, Weasenham Lane, Wisbech, Cambs. They enable an outward load to be carried inside the lining and a return load to be carried in the shell of the tank. Dynabulk tanks are being built by the company for road and rail applications under licence to the Dynabulk Corporation of America for world markets outside the Americas and Canada. The first prototype was completed in June 1969 and a number of tanks is in regular use. Future plans include the production of tanks up to 2200 cu.ft. .capacity.
An outward load is discharged through a central hopper while a return load is discharged through outlets at the ends of the tank. When the material is being loaded through the hatches it expands the bags until the lining is a snug fit in the shell. For unloading, air is introduced into the ends of the tank and the two bags fold up into a small area in the centre of the shell. The two clean ends of the tank can then be loaded with a different material for the return run without contamination by the residue of the first load. Air is introduced into the bags to discharge the load.
Of hypalon-coated Terylene, the bags may be filled with material at temperatures up to 100deg C and are suitable for carrying hot cement. If the vehicle is not required to carry return loads, a hopper type of tank is fitted, while return-load tanks are of the cylindrical type. In practical tests of the system flour has been discharged at a rate of 20 tons /h, industrial sand at 23 tons /h and cement at 40 tons/h.