2.7 Oll SUPPLY FOR INJECTION AND LUBRICATION
Il 1s
extremely important that
the
1nterme-stung
male and
female rotor
lobes
effectively seal off eacti
01her mu1ual
y
without grving rise to wear_
Moreover,
the 1nev1table gap
along
the rotor c1rcumference between
the
successive
grooves
must be
thoroughly
sealed
off
as well
To
achleve
this. a sufficient quantity ol oil 1s inJected into the co--n
pressor and
mixed
w1th the
rcfr,gerall!
as
the
rotors
turn
in
compressing the gas. ThlS 011 has a
muIt1pfe
funcuon 11s
ma,n functions are
fubrlcat1on
and the
internal sealing
referred to. In addibon. the oil takes care of intensive
cool
ing dunng compress,on
and has a silencrng effect.
Furthermore, 011 has to be supplted tor
al
J
otti.er
compressor
lubnca11ng purposes and for the
operallon ol
the capactl�
controf
system
As represented
schematically
in f1g 2.8 twc seoarate
prual
lel oil supply flows to the compressor can be dtsbngu1Sheo
VtZ.:
-
An
oil
flow
under (refrigerant) discharge pressure
for
direct
inject1on Into
the rotor grooves (X14 and X15)
and
tor
supply
to
the baJance
piston
(
X8
)
The 0111njeCIIOl'I, 1$.Cparalely lor male and fomale 10101,
takes
place
via a fixed opening tn the bollom of each
cylindrical
pan of
the
inner rotor housing.
The
opentngs
are sttuated in such a
way
as to cover each mare and
remale
rotor groeve pair
for a
short
penod of ume JUs1
before compress1on commences. consequenlly rmmed.
ately alter the
groove pair
has
been sealed off from the
inlet.
Therefore.
the
existing instal!ahon pressure
dil•
ference(:: d1scharge or condensing pressure minus suc•
!Ion or evaporalmg pressure) 1s sufficient 10 infect ne
required oil quantity·.
- An oll
!low
under pump pressure
(= discharge
pressure-.
3 baJ) for
the capacny
control sllde valve ;>OS1tion1ng
(X10)
and lubnc
a
tion {X1, ), for supply
to
the shaft seal (X9) and
tor bearing lubncat1on (X6.
X12 and X13).
The 011 pump mentioned is the
electnca!ly dr1ven
gear
pump as descnbed
furtheron
1n paragraphes
3.1
and 3.2
For the exact locat1on of aJI the compressor o,I connec1Ions,
refer to paragraph 2.8.
• In the case that the installation pressure difference îs less
lhan
1.5
bar
,
there 1s no
guarantee
ar,y more tor
sufficient
oil injection mlo me rotor grooves.
Therefore. apart trom the
pressure
supply to the balance
piston of the male rotor, all of the ojf supply
to
the
compressor has then to
be
covered
by
a
pump
a1 a
pressure of 3 bar above (refrigerant}
discharge
pressvre.
This full-flow pump 1s a
cont,nuous!y
operatmg. electncally
drrven gear pump, and mounteo in the main oil supply line
trom
the oîl
separator to
the
oil cooler.
As a result !here are two different compressor oad<age 011
systems.
wh1eh are.
descr,�rl
tn ciP-T::i,I '"' l'napter 3 :>
92.01
Compressor Pacitage
GSLP
GRBSSï::i
P:lge
2.7
