Boss Industries Bullet 2, Service And Maintenance User Manual

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Description of Components
The Bullet 2 air compressor contains a Subaru EH72 4-cycle, v-twin, OHV, air cooled, gasoline
engine. This engine has been specially selected to handle the rugged duty required for its operation.
This engine is setup to run on standard unleaded gasoline. The engine speed is modulated by a
pneumatically controlled cylinder piloted by the compressor regulator. This will conserve fuel by only
using the necessary power for the air demand. For detailed information on the engine, refer to the
Engine Operator’s Manual provided separately.
5.1 Engine
5.2 Drive System
Power from the engine is transmitted to the compressor input shaft through specifically selected v-belt
pulley system. Power is transfered to the male rotor of the compressor with two 3VX belts. The pulley
ratio maximizes the engine output with the fewest belts possible for ease of maintenance.
5.3 Compressor Airend
The Boss Industries, Inc. compressor airend is a positive displacement, oil flooded, rotary screw type
unit employing one stage of compression to achieve the desired pressure. Components include a
housing (stator), two screws (rotors), bearings, and bearing supports. Power is transfered from the
drive source to the male rotor by the drive system. The female rotor is driven by the male rotor. There
are five lobes on the male rotor while the female rotor has six roots.
In operation, two helical grooved
rotors mesh to compress air. Inlet air is trapped as the male lobes roll down the female grooves,
pushing trapped air along, compressing it until it reaches the discharge port at the end of the stator and
delivers smooth-flowing, pulse-free air. Being an oil flooded system, the oil serves three purposes:
lubricates the rotating parts and bearings, serves as a cooling agent for the compressed air, and seals the
running clearances.
5.4 Separator System
I. Sump Tank
From the compressor airend, the compressed air and hot oil flow into a steel, ASME coded,
pressure vessel, rated at 200 PSI, that acts as an oil reservoir. This tank is the first of two stages in
separating the oil and compressed air mixture. From the bottom of the separator tank, oil is forced
to the oil filter. Air and an oil mist are forced out the top of the sump tank and flow to the coalescer
element.
II. Coalescer Element
The Coalescer element is a spin-on canister style filter that removes the oil mist from the air as it is
passed on to the minimum pressure orifice. As the air/oil mist passes through the outside of the
media, oil gathers on the interior walls and settles to the bottom of the element. Collected oil is
returned to the compressor airend through the oil return line. The coalescer will filter the oil concen-
tration in the air to less than 3 parts per million.