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Ambient air is cleaned as it is drawn in through the filter
1
.
The air is then compressed in the airend
4
.
The airend is driven by an internal combustion engine
15
.
Cooling oil is injected into the airend. It lubricates moving parts and forms a seal between the ro‐
tors and between the rotors and the housing. This direct cooling in the compression chamber en‐
sures a very low airend discharge temperature.
Cooling oil recovered from the compressed air in the oil separator tank
5
gives up its heat in the oil
cooler
20
. The oil then flows through the filter
21
and back to the point of injection. The internal
machine pressure keeps the oil circulating. A separate pump is not necessary. A thermostatic
valve
19
regulates and optimizes the cooling oil temperature.
The compressed air is released from the cooling oil in the oil separator tank
5
and then passes
through the minimum pressure check valve
37
air distributor
10
. The minimum pressure check
valve always maintains a minimum system pressure to ensure continuous cooling oil flow in the
machine.
The flow direction of the fan wheel
28
and arrangement of the cooling air inlet and outlet deter‐
mine the cooling air flow of the machine within the enclosure. The cooling air continuously flows
through the oil cooler and coolant cooler. The heated cooling air returns through the cooling air out‐
let back into the surroundings.
4.4 Operating modes and control mode
4.4.1 Machine operating modes
The machine operates in the following modes:
■ WARM-UP
─ The inlet valve is nearly fully closed.
─ The minimum intake air volume escapes via the venting valve.
─ The drive engine runs at minimum speed.
■ LOAD
─ The inlet valve is open.
─ The engine runs at maximum speed.
─ The airend delivers compressed air.
■ MODULATING
─ With the help of a control valve (the proportional controller) the degree of opening of the
inlet valve is steplessly varied in response to the air demand.
─ The load and fuel consumption of the engine rises and falls with the air demand.
─ The airend delivers compressed air.
4
Design and Function
4.4
Operating modes and control mode
No.: 902366 10 USE
Operator Manual Portable Rotary Screw Compressor
MOBILAIR M55 PE SIGMA CONTROL SMART pV
41