BRENNER TANK LLC used its Expo '04 in Fond du Lac in June to introduce a new approach to “wetlines” to nearly 100 tank truck industry representatives. The event also included presentations on corrosion, safety, and security.
The new wetline valve (see Modern Bulk Transporter August 2004, page 33) is Brenner's answer to possible Department of Transportation regulations that would prevent product from being retained in and released from loading lines under the trailer. DOT's Research and Special Programs Administration (RSPA) recently sent a revised wetlines proposal to the Office of Management and Budget (OMB) for review prior to publication, probably later this year.
Brenner has applied for a patent for its approach to retain product in the piping, rather than to remove the product. Brenner argues that the problem is not that product is retained in the pipe, but rather than the product escapes from the pipe and could create a hazard. The new wetline valve is designed with two closures. One is to retain product in the tank as currently required and one to retain product in case of an underride incident. Both valves are self-closing and linked to open and close concurrently.
DOT's required shear section is located between the tank and the first closure. If an incident occurs and the shear section fails as designed, the upper closure would remain with the cargo tank to retain product in the cargo tank, and the lower closure would remain at the top end of the piping, retaining all but about one cup of product in the piping.
Stainless quality
Turning to other cargo tank issues, Steve Suess of Stork Technimet told attendees that today's stainless steels are not generally as good as in the past, and more care in selection of construction materials is necessary. This requires good communications between the tank manufacturer and the customer.
New alloys are coming out, and elements are being added to enhance other properties. US virgin grades are a thing of the past as there is more remelting and recycling. There is less rolling and cold finishing and higher residual stress. Steels are slightly less corrosion resistant, he said. Published corrosion tables have value, but do not cover everything that must be considered in specifying a trailer. One solution is to lab test a new product that a trailer will haul before placing the product in a stainless steel trailer.
A panel of cargo tank users discussed corrosion prevention. Bill Ebert of Superior Carriers said proper tank washing is key to reducing the effects of corrosion. Tanks should be washed as soon as possible with de-ionized water. The tank should be dried after cleaning to ambient temperature and dome lids should be left cracked to prevent “sweating.”
Another panel consisting of Brenner engineers said regulatory challenges over the next five years include driver hours of service limitations, security of cargo tanks, closer Agriculture Department scrutiny of sanitary loads, and vehicle dynamics. More electronic monitoring equipment might be specified on trailers.
Danny Shelton of the Federal Motor Carrier Safety Administration provided information on increased involvement of the American Society of Mechanical Engineers in cargo tank design regulations through Section XII. Anything developed by ASME would have to be incorporated into the regulations by the Department of Transportation.