For-hire tank truck carriers, always seeking a back-haul to reduce their traditional 50% empty mileage, have been especially active in recent years developing specialized units to enable them to haul one product outbound, and an entirely different product inbound. One carrier has developed a complete line of vehicles of this type, shown above. The one at left will transport fuel oil in the belly tank, and dry freight on the flat, open top. The next two tanks carry gasoline in compartments on each end, and dry soda ash in the center on the return trip. The next two tanks haul gasoline and liquid caustic soda in a similar manner, and the last is a typical one-way chemical tank for comparison. The gasoline-soda ash tanks above were patterned after the unit at left which hauled wheat in the center compartment. As you can see, it has to be tilted for unloading-a cumbersome procedure by today's dry-bulk unloading standards, but a step forward in developing efficient tank truck transportation. Newest field of tank truck transportation is the movement of dry cement and other powdered, granulated or otherwise flowable dry commodities. Greatest advancement here has been made in fast and thorough unloading methods. Earliest vehicles for this purpose used augers to bring, the material to the rear of the tank, or were simply bottom-dump hoppers, like the double-bottom west coast unit shown here. The Airslide which introduced lowpressure air to fluidize the powder and make it run to an outlet like a liquid was another important advance. Newest designs use somewhat higher pressures or a pressure differential to unload at very high speeds. Rapid development of new designs in this field have increased efficiency and extended the range of commodities handled. The rapid expansion of this field is one more example of the many ways in which the versatile tank truck continually contributes to the economy of the Nation through ever-increasing efficiency. There seems to be no limit to the possibilities for tank truck transportation... July, 1962 Petroleum and Chemical Transporter |