DA Series
Operation Manual
15
(5)
After-cooler assembly
(6)
Oil-gas barrel
The air enters the air compressor and flows through the inlet filter and the inlet valve. The compression of
the screw air compressor is generated by the meshing of a pair of helical rotors (one is male and the other
is female), which are respectively installed on two parallel shafts and in the high-strength cast iron casing.
The inlet and the outlet are located at either ends of the shell respectively. The slot of the female rotor is
meshed with and driven by the male rotor, and the exhaust end employs the bearing to prevent the rotor
axial floating. The oil-gas mixture is exhausted from the outlet of the main engine and enters the oil-gas
separation system which removes the most lubricating oil in the oil-gas separator. The lubricating oil will
flow back this system and enter the cooling system with the compressed air leaving a little PPM oil
content. The after-cooling system consists of a heat exchanger and drain device. The exhausted air after
cooling will condense much vapor contained in the air which can be removed in the posterior pipeline and
equipment terminal of the unit. The inlet valve is closed, the release valve is opened and the compressed
air enters in the inlet valve from the bypass pipeline during unload running.
4.3 Lubricating Oil System
The lubricating oil flows from the oil-gas separator and the oil-gas barrel to the inlet of the cooler and the
bypass port of the heat control valve under the pressure. The exhaust temperature of the compressor can
be controlled above the dew point by the heat control valve. When the air compressor starts up in cold, a
part of the lubricating oil will flow bypass the cooler. When the system temperature rises above the
settings of the temperature control valve, the lubricating oil will flow through the cooler. When the unit is
running under high temperature conditions, all lubricating oil will flow through the cooler. The outlet
temperature of the oil cooler of the air compressor can be controlled to eliminate the possibility of the
condensation of the vapor in the oil-gas separator. The temperature of the oil-gas mixture exhausted from
the unit can be kept above the dew point by maintaining high oil temperature. The lubricating oil with
controllable temperature enters the engine body through the oil filter under the constant pressure.
4.4 Oil-gas Separation System
The oil-gas separation system is composed of the oil-gas barrel with specially designed internal structure,
two-level gathered separator element and cooling oil recovery device. Basic operation principle of the
oil-gas barrel: The oil-gas enters from the inlet and impact the head of the oil-gas barrel to separate the
oil drops from the oil-gas mixture based on the state. The machinery impact can be applied to the oil-gas
barrel, which can separate oil drops with large diameter relying on its own gravity of the oil drop, which is
suitable for the oil drops with diameter greater than 1um.
When using the method of machinery impact, impacting the head by the oil-gas mixture may control the
oil molecules with a certain flow rate so that the oil drops can fall to the bottom of the oil-gas barrel during
discharging and the oil content discharged from the air can be reduced.
