3.3 otl SEPARATOR{S)
Separation of the ei! trom the discharge gas of the com
pressor takes place in one or two oil separators.
In cases 1n which it does not matter that a slight quantrty of
oil enters the refrigeration system with the discharge gas,
only the primary oil separator is used. This separator is a
vertical pressure vessel of large volume, in whîch the gas
flow undergoes such changes in velocity and direction that
heavier drops of oil are thrown out and drip downwards.
Any smaller drops of oil are retained in a steel fibre filter ele
ment (demistor) prior to the
gas
leaving the oil separator.
The separated oil is collectec at the bottom of the separ
ator, which also acts as oil sump of the package. For inspec
tion of the oil level an or! level sight glass îs fitted. A heating
element in the bottom part of the separator ensures that the
oil ternperature is maJntained at the desired level during
standstill of the package.
In refrigeration systems requiring the oil carry-over to be mi
nimized, a secondary oil separator is installed behind the pri
mary oil separator (see flow diagrams, fig. 3.2 to 3.5). Thls
secondary oil separator consists of a divided cylindrical
vessel in which a removable coalesceing element is fitted.
The separated oil, after reaching a certain level, is returned
under discharge pressure via an automatic float vaJve to
the male rotor oil injection line of the compressor.
3.4 ELECTRIC CAPACITV CONTROL ADJUSTING
DEVICE
GENERAL
To operate the capacrty control regulatrng shaft of the com·
presser (see fig. 2.6) manually (by push-buttons) or auto
matically (by the control system of the installation), a simple
and reliable electric adjusting device, called the "Electrical
slide Valve Actuator" (EVA) is used. This is a standard
accessory, factory-mounted on and ln line with the hydraulic
cylinder of the compressor as shown in fig. 3.6.
Apart trom two different position indfcators (explained
further on), there is only one type and size of this device
available, suitabfe
tor
all compressor types and for all
existing built-in volume ratios.
DESCRIPTION OF STANDAAD DEVICE
Fig. 3.7 A represents a longitudinal section of the electric
slide valve actuator. lt consists of a small reversible electric
motor {9) with brake mechanism (8) and speed reductor (4)
which drives in either directton a central output shaft (11)
and a cam post (7), all mounted inside an aluminium
housing (10), which on lts turn, is bolted by means of an
intermediate bush (3) to a disc on the hydraulic cytinder of
the compressor, so that the output shaft is coupled via a
carrier pin (2) in line with the compressor regulating shaft
(1 ).
When the capacity controJ slide valve inside the compressor
has reached either its fuil load {max. capacity) or minimum
laad {min. capacity) position, the adjusting motor is stopped
automatically by means of two micro limit switches (6),
mounted on a adjustîng plate inside the housing and each
of them activated by one of the two cams (5), fitted around
the cam post (7). The minimum capacity limit switch (th�t is
the second switch seen from below) has a twofold funct1on;
H also serves to prevent the compressor-motor from being
started as long as the capacity control mechanism is noi yet
in its minimum position. See also electric wiring diagram in
Paragraph 3.6.
top view of indicator
30 turns indicator
62 turns lndîcator
\F��?f-W---tt----
a
-�-1
r-
+J-
6
.l..-r-l-rr.
.
,
�
il
4
i---
----
--,.,.,o'+---- 3
'i----......;:;;.:.+�---t,_
2
,
c=,:,::i
FIG. 3.7A ELECTRIC SLICE VALVE ACTUATOR
Page 3.8
Compressor Package GSLP
92.01
