Air Dryer Said to Prevent Brake Line Damage

Damage caused by clogged air brake valves could be prevented using a product designed to flush contaminants and water from trailer air lines, according to AlliedSignal officials.

The Bendix trailer system-guard air dryer also has a mechanism to prevent debris from getting into air brake lines in the first place. Its manufacturer, AlliedSignal Truck Brake Systems, expects to have the product on the market in October.

Jeff Knapton, product marketing director at Bendix, said the component works best when used in conjunction with a tractor air dryer. But it can prevent clogging if the tractor dryer system is malfunctioning, he said.

The two-chambered product is 3.6 inches tall, 2.5 inches wide and 11.8 inches long. It weighs about 5 pounds and is mounted on the trailer cross member or chassis.

The guard uses high-surface-area desiccant beads, to which moisture and contaminants cling as air goes through the lines, Knapton said.

Air rushes into the service line through the bottom chamber of the guard and is filtered as it goes back to the trailer brakes. Moisture and alcohol are flushed from the guard when the parking brake is applied, and the return air blasts the contaminants off the desiccant beads and into the air, he said.

The control line works very much the same way. Each time the brakes are applied, air goes through the guard’s chamber to the trailer brakes. When the brake is released, outgoing air flushes the control chamber clean, Knapton said

At an estimated cost of less than $200, the trailer system guard prevents valve damage because the purging process eliminates the need to use alcohol to stop pneumatic freeze-ups, Knapton said. Alcohol can cause gumming or cracking of valves, he said.