Toroidal LPG tanks improve space utilization
While toroidal tanks have been popular in European vehicles for 20 years, they were only first introduced in the United States about a year ago, towards the end of 2014. Compared to Europe, the U.S. is a different market, focused on the conversion of new or existing fleet vehicles by propane autogas system integrators. Nevertheless, interest in toroidal tanks is strong and growing among U.S. integrators, for the same reasons they are by European vehicle OEMs – a flexible design option thanks to the unique tank shape, along with reliable performance and value over thousands of miles of driving.
Toroidal tanks in the U.S.
U.S. fleet operators have become more interested in vehicles fueled by propane autogas over the last five years. At first, only cylindrical fuel tanks were available to system integrators completing conversions, but that changed with the introduction of toroidal tanks in the U.S. in late 2014 by Worthington Industries.
Worthington is the 100 percent owner of Stako, based in Slupsk, Poland, which is the manufacturer of all U.S. toroidal tanks and ensures they are constructed in accordance with American Society of Mechanical Engineers (ASME) regulations. (In Europe, toroidal tanks are certified to United Nations Economic Commission for Europe R67 regulations, with additional regulations required in many countries.)
As it turned out, toroidal tanks provided the design option integrators were seeking, for the simple fact that most spaces within fleet vehicles are square or circular-shaped. A toroidal tank’s unique shape allows them to better utilize the space that’s already there within a fleet vehicle, like a light-duty pickup truck, a package delivery van or a police cruiser or taxicab.
For example, take a light-duty pickup truck that serves a small town’s public works department. A cylindrical tank could be installed beyond the truck’s cab, but it takes up 30 percent of the truck’s bed space, meaning there is less room for cargo. A toroidal tank installed in the spare-tire area under the truck bed, near the axle, gains back every inch of that truck’s bed space. That means all tools and material necessary to complete a project can fit in the truck bed, resulting in just one trip to the work site. Keep in mind, also, that the need for a spare tire is lessened today due to options like tire-repair sprays.
Toroidal tanks are available in the U.S. in eight sizes – ranging from 23.6 inches in diameter and 9.8 inches in height to 28.4 inches in diameter and 13.8 inches in height. Current U.S. toroidal tanks are made for vapor service and are constructed of steel for durability, with a baked-on powder coat application that maximizes corrosion resistance. They arrive ready for installation, with all valves and fittings enclosed in a vapor box, along with multiple fitting adjustments so they can be easily configured for the fleet vehicle.
U.S. integrator feedback to toroidal tanks has been positive. In addition to better space utilization, they are pleased with how they contribute to seamless vehicle conversion, and that the eight models available are a standard product with adjustable brackets. It also helps that there has been no issue with tank performance, allowing integrators to maximize the performance and profitability of customer propane autogas programs.
The future is bright for toroidal tanks in the U.S. Worthington has seen substantial interest from propane autogas system integrators in the short time they have been available, so as the industry continues to learn more about the benefits of these tanks, interest should continue to grow, as well. Demand could also be impacted by factors such as continued fleet operator interest in propane autogas-fueled vehicles as an option to reduce both fuel costs and emissions, as well as growth of propane autogas refueling infrastructure.
Wayne Powers is the Alternative Fuels General Manager for Worthington Industries, manufacturer of fuel tanks for alternative-fuel vehicles
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