MANIFOLD & VALVE GP 1378795 - Caterpillar

Operation
The operation of the air dryer is given in two parts, the charge cycle and the purge cycle.Charge Cycle
CHARGE CYCLE 1. Line from air compressor to air dryer.2. Purge volume.3. Line to air compressor governor.5. Line to air reservoir.6. Check valve.7. Check valve.8. Purge orifice.10. Dessicant cartridge.11. Oil filter.12. Sump.With the air compressor in its "loaded" or compressing cycle, air under pressure is sent to the air dryer from the air compressor through air supply line (1). When the air enters the Air Dryer, the velocity (speed) of the air goes down and cools. Much of the oil and water in the air drops into the sump (12). The direction of the air flow is to the bottom of the Air Dryer where its direction is reversed and more water and oil go into the sump.The air now goes through the oil filter (11) and some oil and foreign material is removed, but the water vapor is not removed. At this point, the air is still saturated (full) of water.The filtered air and vapors go up into the bottom of the desiccant drying bed of the desiccant cartridge (10) and the adsorption procedure begins. Water vapor is removed from the air by the desiccant.The unsaturated "dry air" goes through the check valve (7) and purge orifice (8) into the purge volume (2). From the purge volume (2) the air goes through check valve (6), through line (5) to the air reservoir and line (3) to the air compressor governor.Purge Cycle
PURGE CYCLE 2. Purge volume.4. Unloader line from air compressor to purge valve.6. Check valve.8. Purge orifice.10. Desiccant cartridge.12. Sump.13. Heater.14. Purge valve opening.15. Purge valve piston.16. Thermostat.17. Purge valve plunger.18. Purge valve exhaust deflector.19. Seat.For the purge or regeneration cycle, the air flow through the desiccant bed of the air dryer goes in reverse.When the air pressure from the air compressor goes up to high pressure setting of the governor, it goes through the governor and into the area below the unloader pistons in the air compressor cylinder block. The unloader pistons go up and the unloader plungers move up and hold the inlet valves off of their seats.With the inlet valves held off their seats, air goes through the unloader line (4) into the purge valve opening (14). The purge valve plunger (17) is moved off of its seat (19). The sudden opening of the the purge valve piston (15) and purge valve plunger (17) permits the air pressure that is in the dryer to exhaust the condensation and foreign material that has gathered in the sump (12) past the purge valve exhaust deflector (18) to the atmosphere. The sudden decompression (decrease in air pressure) of the drying bed of the desiccant cartridge (10) removes moisture from the pores (cavitites) of the micro-crystalline particles that make up the drying bed. After the rapid decompression caused when the purge valve is opened, air goes from the purge volume (2) through the purge orifice (8) into the desiccant cartridge