Brenner unveils wet lines solution
Aug 1, 2004 12:00 PM
A HIGHLIGHT of this year's Brenner Expo on June 16 was the introduction of a newly developed wet-line valve designed specifically to reduce the likelihood of a wetlines related accident. The Brenner system takes a markedly different approach to the wet-lines issue than previously proposed solutions.
The idea behind the valve is that product retained in the pipe is not necessarily a hazard. The true hazard is when product spills to the ground. The Brenner wet-line valve is designed to retain product in the pipe in the event of a collision.
Brenner's wet line valve has two closures — one to retain product in the cargo tank as is currently regulated and one to retain product in the piping in the event of an underride incident. Both closures are self-closing and linked to open and close concurrently. The Department of Transportation-required shear section is located between the two closures. If, in the event of an impact, the shear section fails as intended, the upper closure remains with the cargo tank to retain the product in the cargo tank. The lower closure remains with the piping, retaining all but about one cup of product in the piping.
Working in conjunction with Fort Vale, a scale model, working prototype valve was developed and was displayed at this year's Brenner Expo. Developed by Jack Rademacher, Brenner research and product development engineer, the Brenner wet line valve provides the following advantages:
Valve is designed to retain product in the outlet pipe in the event of an impact.
Valve technology in a single poppet arrangement has been proven and in use for many years.
While additional testing must still be performed, the valve is expected to have a flow rate comparable to current four inch industry “high flow” valves.
Both poppets rotate out of the flow path allowing nearly unrestricted flow.
Valve is dimensionally in compliance with TTMA RP 28-99, which means the valve can be retrofitted to the current fleet.
Installing the valve requires no “hot work” to the tank trailer.
As designed, the valve (dependent on additional impact testing) meets current regulation requirements and could be installed in a fleet for testing without additional DOT approvals.
There is a very minimal weight increase.
Both poppets are fully open when loading and fully closed when in transit.
Total volume of product held between the poppets is approximately one cup (0.25 liters).
There is no concern of creating explosive vapor concentrations within the piping.
The linkage between the individual poppets can be easily removed allowing each poppet to be leak tested separately.
Maintenance of the valve is similar with the current fleet requirements and requires little or no additional training of fleet maintenance personnel. This wetlines solution requires no ECU's, pumps, retain probes.
The look and feel to the operator of the cargo tank would be essentially unchanged.
Brenner Tank has applied for US patent protection for this concept. This is the first patent ever applied for by Brenner Tank in its modern history.
The primary focus for the new Brenner wet lines system is on petroleum transports, which typically are filled by pumping product through external piping (bottom loading). This piping can retain 40 to 50 gallons of gasoline (hence the term “wet lines”).
These wet lines are vulnerable in a side impact by another vehicle. If a side impact by a vehicle is substantial enough, the piping is designed to break via a shear section to protect the cargo tank and prevent the entire contents of the cargo tank from being released. At issue, however, is the 40-50 gallons of gasoline in the piping.
The same shear section designed to protect the tank in the event of a collision may also be the mode by which the gasoline in the piping is released. If the gasoline retained in the piping is released in an accident, the hot exhaust system from the colliding car is enough to set the gasoline on the ground on fire which in-turn can cause the cargo tank contents (8,000 gallons or more) to ignite.
In the late 80's, DOT recognized the potential problem and set out to ban the practice of carrying product in these unprotected wet lines. By that time, however, the industry had become entrenched in the practice of bottom loading and there was no viable way of purging the product from the piping so DOT simply indicated to the industry the risks they accepted by carrying product in the piping and strongly suggested to the industry to come up with a method to eliminate the problem.
The National Transportation Safety Board (NTSB) has continued to push the DOT to find a solution to the wet lines issue however and in 2003 the DOT indicated that they planned to do something. Work on the wet lines rule reportedly is still underway at DOT, and a final regulation could be published at any time.
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