Abstract: An apparatus for operator controlled purging of the tanks of a pressurized air reservoir of a vehicle air system comprises an air actuated normally closed drain valve mounted to an underside of each tank, a source of pressurized air engaged to each drain valve, and a controller for each valve engaged downstream of the source, and within a driver area of the vehicle, the controller when activated, allowing for communication between the source and the drain valve for opening of the valve. The method for using the apparatus in testing air system integrity includes the steps of draining and refilling each tank individually in a pre-defined sequence while monitoring driver area mounted indicators of air pressure levels and testing functionality of an air system operated service brake system of the vehicle by carrying out the pre-defined sequence.

Abstract: An apparatus for operator controlled purging of the tanks of a pressurized air reservoir of a vehicle air system comprises an air actuated normally closed drain valve mounted to an underside of each tank, a source of pressurized air engaged to each drain valve, and a controller for each valve engaged downstream of the source, and within a driver area of the vehicle, the controller when activated, allowing for communication between the source and the drain valve for opening of the valve. The method for using the apparatus in testing air system integrity includes the steps of draining and refilling each tank individually in a pre-defined sequence while monitoring driver area mounted indicators of air pressure levels and testing functionality of an air system operated service brake system of the vehicle by carrying out the pre-defined sequence.

Abstract: The spring-operated parking brakes of a tractor-trailer are controlled by a novel electro-pneumatic system. Pneumatic valving through which compressed air is conducted is mounted on the tractor chassis and coupled via an electronic circuit to two hand-operated control devices on the dash of the tractor cab, one for the trailer parking brakes only and the other for the tractor parking brakes. The latter device inherently operates the trailer parking brakes via the circuit if they are not already applied, and the circuit incorporates a sequencing function for operating the trailer brakes slightly before the tractor brakes when the tractor parking brake control is operated. Compressed air for the system is obtained via an engine-driven compressor which charges a tank. A pressure transducer monitors tank pressure for the circuit with the circuit maintaining tank pressure through selective loading and unloading of the compressor. Purging of the dryer is coordinated with compressor unloading.

Abstract: The spring-operated parking brakes of a tractor-trailer are controlled by a novel electro-pneumatic system. Pneumatic valving through which compressed air is conducted is mounted on the tractor chassis and coupled via an electronic circuit to two hand-operated control devices on the dash of the tractor cab, one for the trailer parking brakes only and the other for the tractor parking brakes. The latter device inherently operates the trailer parking brakes via the circuit if they are not already applied, and the circuit incorporates a sequencing function for operating the trailer brakes slightly before the tractor brakes when the tractor parking brake control is operated. Compressed air for the system is obtained via an engine-driven compressor which charges a tank. A pressure transducer monitors tank pressure for the circuit with the circuit maintaining tank pressure through selective loading and unloading of the compressor. Purging of the dryer is coordinated with compressor unloading.