Performer® Scroll Compression Principle - Danfoss Performer SM Series Selection & Application Manuallines

peRFoRMeR® scRoll coMpRession pRinciple
In a Danfoss Performer®
compressor, compression is performed
by two scroll elements located above
the motor (see adjacent figure). Suction
gas enters the compressor at the suction
connection, enters at the bottom of the
motor housing and flows around the
motor. Oil droplets separate from the
suction gas and fall into the oil sump. All
suction gas passes around the electric
motor, ensuring complete
cooling in all applications. After cooling
the electric motor, the gas enters the
scroll elements where compression
takes place.
A check valve is located directly above
the fixed scroll discharge port; this
feature prevents the compressor from
running backwards once the power has
been switched off.
The figure below illustrates the entire
compression process.
There are two scroll elements: an orbiting
scroll and a fixed scroll. The center of
the orbiting scroll traces a circular path
around the center of the fixed scroll.
This movement creates symmetrical
compression pockets between the two
scroll elements. Low pressure gas is
trapped in each crescent-shaped pocket
as it gets formed; continuous motion
of the orbiting scroll serves to seal the
pocket, which decreases in volume as
the pocket moves toward the center of
the scroll .
During three complete orbits the pocket
of gas becomes smaller and pressure
rises. After the third orbit, the gas, at
maximum pressure, has reached the
central discharge port where it leaves
the compressor.
Compression in a scroll is a continuous
process: when one pocket of gas is being
compressed during its second orbit,
another quantity is entering the scrolls
and yet another is being discharged all
at the same time.
4
scroll
motor
First orbit:
SUCTION
Second orbit:
COMPRESSION
Third orbit:
DISCHARGE