The Amazing Scroll Compressor!
(What it is. How it works.
Why it’s so efficient.)
The concept
or “theory” of compressing
a gas by turning a curled, spiral (“scroll”)
form against another fixed spiral form, is nearly a
century old. However it has only been in the past 25
years, with the widespread use of computers and other
advanced technology, that manufacturers have been able
to obtain the critical tolerances required to make
the “theory” practical.
One such company…a leader in the industry…is
Copeland. In the late 1980s, they turned theory into
practical reality. Copeland Scroll ® compressors
employ two identical, concentric scrolls, one inserted
within the other.
One scroll
remains stationary as the other
scroll orbits around it to compress
refrigerant gas vapors from the evaporator to the condenser
of the refrigerant path .
The stationary
scroll contains the refrigerant
gas discharge port. The design of
the orbiting scroll enables it to gather gas vapors
at the perimeter of the scroll, pocket the refrigerant
gas and compresses it as continues to orbit.
It continues to compress the
gas by moving it through successively
smaller “pockets” formed by the scroll’s
rotation, until it reaches maximum pressure at the
center of the chamber. There, it’s released through
a discharge port in the fixed scroll. During each orbit,
several pockets are compressed simultaneously, so operation
is virtually continuous.
It is predicted that scroll compressors will
eventually replace the majority of reciprocating compressors
in most cooling system applications because of their
higher efficiency performance and other operating characteristics.
From the graphic
that follows, you can trace
the path described in the preceding paragraphs. (1)
The refrigerant gas enters the opening between the
fixed and orbiting scrolls at point “A”.
It is trapped in a specially designed pocket and moved
along between the walls of the fixed and orbiting scrolls
being constantly compressed until after 3 rotations,
it is discharged at an opening in the center of the
scroll. This is a continuous process with other pockets
of gas in various stages of compression following. |
