User manual BENDIX TU-FLO 750 COMPRESSOR

[. . . ] ® Bendix® Tu-Flo® 750 Air Compressor DISCHARGE VALVE STOP DISCHARGE VALVE UNLOADER COVER AIR DISCHARGE CYLINDER HEAD WATER OUTLET WATER INLET AIR INLET DISCHARGE VALVE SPRING PISTON DISCHARGE VALVE SEAT CRANKCASE PISTON RINGS CONNECTING ROD GOVERNOR MOUNTING PAD CRANKCASE CRANKSHAFT BENDIX® TU-FLO® 750 AIR COMPRESSOR (CROSS SECTION) PIECE NO. TAG DESCRIPTION The function of the air compressor is to provide and maintain air under pressure to operate devices in the air brake and/or auxiliary air systems. The Tu-Flo® 750 compressor is a two cylinder single stage, reciprocating compressor with a rated displacement of 16. 5 cubic feet per minute at 1, 250 RPM. The compressor assembly consists of two major subassemblies, the cylinder head and the crankcase. [. . . ] 24 In the ping tank or compressor discharge aftercooler (8. 0) . 24 Page Number Test Procedures (1) Oil Leakage at Head Gasket . 29 (3) Compressor Discharge and Air Dryer Inlet Temperature . 32-34 Maintenance & Usage Guidelines Maintenance Schedule and Usage Guidelines (Table A) . 18 *This guide is only for vehicles that use desiccant air dryers. 16 Introduction to the Air Brake Charging System Powered by the vehicle engine, the air compressor builds the air pressure for the air brake system. The air compressor is typically cooled by the engine coolant system and lubricated by the engine oil supply. The compressor's unloader mechanism and governor (along with a synchro valve for the Bendix® DuraFloTM 596 air compressor) control the brake system air pressure between a preset maximum and minimum pressure level by monitoring the pressure in the service (or "supply") reservoir. When the air pressure becomes greater than that of the preset "cut-out", the governor controls the unloader mechanism of the compressor to stop the compressor from building air and also causes the air dryer to purge. As the service reservoir air pressure drops to the "cut-in" setting of the governor, the governor returns the compressor back to building air and the air dryer to air drying mode. As the atmospheric air is compressed, all the water vapor originally in the air is carried along into the air system, as well as a small amount of the lubricating oil as vapor. The duty cycle is the ratio of time the compressor spends building air to the total engine running time. Air compressors are designed to build air (run "loaded") up to 25% of the time. Higher duty cycles cause conditions that affect air brake charging system performance which may require additional maintenance. Factors that add to the duty cycle are: air suspension, additional air accessories, use of an undersized compressor, frequent stops, excessive leakage from fittings, connections, lines, chambers or valves, etc. The discharge line allows the air, water-vapor and oil-vapor mixture to cool between the compressor and air dryer. The typical size of a vehicle's discharge line, (see column 2 of Table A on page 18) assumes a compressor with a normal (less than 25%) duty cycle, operating in a temperate climate. See Bendix and/or other air dryer manufacturer guidelines as needed. When the temperature of the compressed air that enters the air dryer is within the normal range, the air dryer can remove most of the charging system oil. If the temperature of the compressed air is above the normal range, oil as oil-vapor is able to pass through the air dryer and into the air system. Larger diameter discharge lines and/or longer discharge line lengths can help reduce the temperature. The discharge line must maintain a constant slope down from the compressor to the air dryer inlet fitting to avoid low points where ice may form and block the flow. If, instead, ice blockages occur at the air dryer inlet, insulation may be added here, or if the inlet fitting is a typical 90 degree fitting, it may be changed to a straight or 45 degree fitting. [. . . ] Here are some Do's and Don'ts for prevention and thawing. Do maintain freeze prevention devices to prevent road calls. Don't let evaporators or injectors run out of methanol alcohol or protection will be degraded. Check the air dryer for proper operation and change the desiccant when needed. [. . . ]