A refrigerating plant is used in cases where a certain
room or certain materials are to be brought up to or
be maintained at a temperature lower than the
ambient temperature. This low temperature is
brought about by the evaporator of the
refrigerating system. In it a liquid refrigerant
evaporates due to its being maintained artificially at
low pressure; the heat required for this evaporation
is withdrawn from the surrounding atmosphere.
The function of the compressor consists in
maintaining this low pressure in the evaporator
and this by continuously sucking the vapour thus
formed from the evaporator. Therefore the name
“suction pump” would have been more
appropriate for this machine. It derives its present
name from the fact that it compresses the sucked
vapour, which thus reaches a high pressure,
thereby strongly increasing in temperature.
However, this high pressure also involves a higher
temperature at which the vapour passes into
liquid. This temperature is above the ambient
temperature; hence it is possible for the
compressed vapour to be condensed on an air or
water cooled surface.
This process takes place in the condenser. The
liquid thus formed is fed from the condenser to
the evaporator again in order to evaporate there
anew. In the line between the two apparatuses, a
liquid regulator is fitted, which ensures that the
right amount of refrigerant flows to the
evaporator and maintains the pressure difference
between condenser and evaporator.
The correct operation of the compressor highly
depends on the rest of the plant. If, for example,
the installation contains too many impurities, the
compressor may get out of order; also, when the
plant itself has been dimensioned, assembled or
installed incorrectly, the result may be
malfunctioning of or damage to the compressor.
In the event of compressor failure, it is therefore
mostly necessary also to seek the causes in the
other elements of the plant or in a shortage or
excess of refrigerant charge.
In general it is essential, therefore, to have on
hand an operating manual of the plant. Only then
will it be possible to report in time any deviations
from the normal operating conditions of the plant
and take prompt action before serious
breakdowns occur.
Refrigeration Division
Grasso
2. FUNCTION OF THE COMPRESSOR
IN THE REFRIGERATION PLANT
v002.97.10.en
Refrigeration Compressors Series RC9
Page 2.1
