Screw Compressors - Daikin EWWQ-AJYNN Service Manual

Maintenance
1.2

Screw Compressors

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The newest Stargate™ single-screw compressor has a well balanced compression mechanism which
cancels the screw rotor load in both the radial and axial directions. Inherent to the basic single-screw
compressor design is the virtually load-free operation, that gives main bearing design life of 3-4 times
greater than twin-screws, and eliminates expensive and complicated thrust balancing schemes. The
two exactly opposed gaterotors create two exactly opposed compression cycles. Compression is
made at the lower and upper parts of the screw rotor at the same time, thus cancelling the radial loads.
Also, both ends of the screw rotor are subjected to suction pressure only, which cancels the axial loads
and eliminates the huge thrust loads inherent in twin-screw compressors.
Oil injection is used for these compressors in order to get high COP at high condensing pressure.
EWWQ-AJYNN units are provided with an high efficiency oil separator to maximise oil extraction.
Compressors have a infinitely variable capacity control down to 25% of its total capacity. This control
is made by means of capacity slides controlled by microprocessors.
Standard start is star-delta type; Soft start type is available (as option) in order to have lower inrush
current.
ESIE07-05
Part 5 – Maintenance