FIGURE 5 | FIGURE 6 |
ENGINE LUBRICATED TYPE |
had either die cast aluminum, cast ductile iron, or forged steel rods which were not rifle drilled but were drilled at the top of the rod. The wrist pins and bushings are lubricated by oil dripping from a
PISTON WRIST PIN | WRIST PIN |
LOCK WIRE | BUSHING |
WRIST PIN | CAST IRON |
PISTON | |
OIL | STEEL |
PASSAGE | CONNECTING |
| ROD |
| OLD DESIGN |
| “CATCH FUNNEL” |
WRIST PIN |
|
BUSHING |
|
| DIE CAST |
| PISTON |
| DIE CAST |
| CONNECTING ROD |
| NEW DESIGN |
|
|
FIGURE 7- PISTONS & CONNECTING RODS
A nameplate is attached to the crankcase of all compressors. It shows the piece number, type and serial number (Fig. 8). A nameplate with a black background denotes a new compressor, whereas a nameplate with a red background designates that the compressor is a factory reconditioned unit. All compressors are identified by the piece number which is the number to use when reference is made to a particular compressor. The type and serial number is supplementary information.
FIGURE 8 - COMPRESSOR NAMEPLATE
OPERATION
GENERAL
All compressors run continuously while the engine is running, but actual compression of air is controlled by a governor, which stops or starts the compression of air by loading or unloading the compressor in conjunction with its unloading mechanism. This is done when the air pressure in the system reaches the desired maximum or minimum pressures.
| TO RESERVOIR | |
DISCHARGE | INLET VALVE | |
UNLOADER PLUNGER | ||
VALVE | ||
| ||
PISTON | INTAKE | |
| ||
| STRAINER | |
| TO GOVERNOR | |
| STROKE | |
| INTAKE | |
|
| |
FIGURE 9 |
|
INTAKE AND COMPRESSION (Loaded)
During the down stroke of the piston, a slight vacuum created above the piston causes the inlet valve to move off its seat. Atmospheric air is drawn in through the compressor intake, by the open inlet valve, and on top of the piston (Fig. 9). As the piston starts its upward stroke, the air that was drawn in on the down stroke is being compressed. Now, air pressure on top of the inlet valve plus the force of its spring, returns the inlet valve to its seat. The piston continues the upward stroke and compresses the air sufficiently to overcome the discharge valve spring and unseat the discharge valve. The compressed air then flows by the open discharge valve, into the discharge line and on to the reservoirs (Fig. 10).
| TO RESERVOIR | |
DISCHARGE | INLET VALVE | |
UNLOADER PLUNGER | ||
VALVE | ||
| ||
PISTON | INTAKE | |
STRAINER | ||
| ||
| TO GOVERNOR |
STROKE
COMPRESSION
FIGURE 10
3