Interpretation ID: nht91-6.8

DATE: September 24, 1991

FROM: Wayne Trueman -- Plant Manager, BX-100 International

TO: Marvin Shaw -- Chief Counsel Office, U.S. DOT

TITLE: None

ATTACHMT: Attached to letter dated 9-16-91 from Paul Rice to Wayne Trueman (A38; Std. 121); Also attached to letter dated 7-31-91 from Wayne Trueman to Barry Felrice (OCC 6314)

TEXT:

This is in response to the letter of September 16, 1991 from Chief Counsel Paul Jackson Rice. I would like to thank Mr. Rice, yourself, and the other staff members who provided the information that went into the above letter.

One point that I believe needs clarification is the second sentence of paragraph one (copy enclosed). The BX-100 Brake Equalizer is NOT a valve, and has no impact what so ever on the axle to axle brake application timing. Having these units centrally installed between the brake chambers of EACH braking axle, only effects the air application at the individual axle ends into whose air system they are installed.

Per the Webster's New World Dictionary, a VALVE is: "Any device in a pipe or tube that permits a flow in one direction only, or regulates the flow of whatever is in the pipe, by means of a flap, lid, plug, etc. acting to open or block passage."

The function and intent of the BX-100 Brake Equalizer is simply to absorb brake system application PRESSURE variations. There is no air flow within this system once it is pressurized by the relay or quick release valve which also control the overall braking pressure applied to the brake ends. The only other pressure variations in the system are the various internal and externally induced air spikes. Having the BX-100 Brake Equalizers installed between the brake chambers, absorbs or removes the induced system air pressure variations. These high speed transient pressure variations during braking are normal and are caused by changes in the road surface, out of round brake drums, glazed brake pads, out of adjustment slack adjusters, and a host of other possibilities. The BX-100's absorb these variations and provide a more consistent brake application pressure which results in a decrease of heat production at the brake end and a resulting decrease in wear in all affected components. Since equal pressure is maintained, the driver retains complete control of his vehicle and is able to bring it to a shorter, safer, straight line stop.

Once again, thank you for your time and assistance in answering the various questions that I have submitted to your offices.