GRASSO Screw Comp - Product Information
GRASSO Screw Comp - Product Information
GRASSO Screw Comp - Product Information
Refrigeration Division
SCREW COMPRESSORS
Series SH, MC and LT
Product Information
2004/4
_040000_pi_sc__gbr_.doc
PRODUCT INFORMATION
Grasso
SCREW COMPRESSORS
DIRECTORY
Refrigeration Division
Introduction
040 015gbr
Philosophy of Series
040 040gbr
Product name
040 200gbr
040 300gbr
Limits of Application
040 310gbr
Main Dimensions
Series SH
Types C, D
040 400gbr
Main Dimensions
Series SH
Types E, G
040 410gbr
Main Dimensions
Series MC
Types H, L, M, N
040 420gbr
Main Dimensions
Series LT
040 430gbr
Main Dimensions
Series LT
Types XE, XF
040 440gbr
040 500gbr
040 510gbr
Electric Connections
040 520gbr
040 600gbr
Coupling Requirements
040 610gbr
Starting Conditions
040 620gbr
Operational Monitoring
040 630gbr
Lubricationg Oils
040 721gbr
040 730gbr
P+I Diagrams
040 800gbr
Series SH
Series MC
Series LT
03.2004/2
Series SH, MC
Overall Concept
AISH02-1gbr
Description of Design
AISH03-1gbr
AISH04-1gbr
Overall Concept
AIMC02gbr
Description of Design
AIMC03gbr
AIMC04gbr
Overall Concept
AI_LT_02gbr
Description of Design
AI_LT_03gbr
Connections
Types P, R, S, T, V, W, Y
AI_PY_04gbr
Connections
AI_Z_XF_04gbr
INTRODUCTION
Grasso
Refrigeration Division
SCOPE OF APPLICATION
The screw compressors are oil injected dual rotor
positive displacement machines.
The machines are available as standard refrigeration
compressors for single-stage operation, as boosters as
well as heat pump compressors.
The compressors can be applied in cold storage houses,
in food industry (slaughter houses, breweries, dairies,
food- and vegetable processing), air conditioning,
chemical and petrochemical industries, refrigerating,
cooling and air conditioning plants onboard ships as
well as heat pump operation.
The refrigerants NH3, R22, R134a, R404A, R507 and
refrigerant mixtures can be used up to a discharge
pressure of 362.5 psia (28 bar abs.).
For these refrigerants, lubricating oil is chosen in
accordance with data sheet 040 700e.
The compressors are directly driven by the electric
motor through a flexible coupling and are designed for
speeds of 50Hz and 60Hz.
Supply range
The whole supply range of screw compressors comprises
19 types subdivided into the following 3 series:
Series SH, SemiPacks, including 4 types (C, D, E, G) with
a theoretical swept volume ranging from 231 to
372 m/h.
Series MC, Compact-Screw compressors, including
4 types (H, L, M and N) with a theoretical swept volume
ranging from 471 to 860 m/h.
Series LT, High Performance-Screw compressors,
including 11 types (P, R, S, V, W, Y, Z, X, XB, XC, XD)
with a theoretical swept volume ranging from 805 to
5800 m/h.
The 3 series differ from each other in the degree of
integrated functional components of the oil and
refrigerant circuits.
SCREW COMPRESSORS
Series LT - High Performance Screw compressors require external filters and valves as well as a separate
oil feed system (exception: types W, Z, XA, XB, XC
and XD with attached solenoid valves).
All compressors feature stepless capacity control and
can be provided with self-adjusting, variable volume
ratios (parallel slides, system PS with series SH and MC;
tandem slides, system TS with series LT). Compressors
with built-in Vifixed volume ratios 2.6 to 4.8 ie: 5.5 are
available. The value Vi is calculated for the specific
operation condition in the compressor selection
program COMSEL.
All types are fitted with an economiser connection as
well as connections for refrigerant injection (liquid
injection) and for returning oil from the plant system.
Compressors with high pressure ratios are equipped
with a self-adjusting system for vibrationfree partial
load operation.
Before delivery, each compressor is subjected to a test
run with nitrogen in the pressure range of the future
application which is proven by a works test certificate
accompanying each compressor. On request, a
certificate of acknowledged classification societies, e.g.
TV, Lloyds Register of Shipping, Germanischer Lloyd,
Norske Veritas, Bureau Veritas, will be provided.
A comprehensive quality assurance system based on
DIN ISO 9001 and comprising all stages from design/
development, manufacturing, assembly and testing
through to customer service guarantees excellent
quality of the Grasso Screw compressors.
The compressors are delivered without oil.
All connections are closed, and the compressors are
filled with dry nitrogen (0.2 psig.).
Each compressor comes complete with a users manual
with instructions on operation, installation,
maintenance and repair and showing the set of tools
and spare parts required.
03.2002/1
INTRODUCTION
Grasso
Refrigeration Division
SCREW COMPRESSORS
TECHNICAL FEATURES
Rotors
The rotors are made of forged tool steel. They are
designed according to low energy consumption criteria
(patented profile with optimised main dimensions). The
primary rotor is driven by the motor, whereas the
secondary rotor is directly driven by the primary rotor
by means of a thin oil film.
Shaft sealing
The driven main shaft is sealed by means of a ring
bearing oil seal with a rotating ring and a fixed ring
(impregnated carbon/ steel). The seal is designed to
relieve load variations whilst containing the oil charge
and the thin oil film between the rings results in a long
service life.
Casings
The casings are made of laminated grey cast iron and
can be applied with discharge pressures up to 406.1
psia (28 bar abs.).
Capacity control
Stepless adjustment of the hydraulic mechanism enables
both the suction volumetric capacity to be changed
within the full load range of the compressor from 100%
to minimum capacity. Compressors with a variable
volume ratio operate according to a system of
combined Vi partial-load control.
Storing
The compressors of the series SH and MC are
completely equipped with rolling bearings. Capacity
improving cylindrical-roller bearings for radial load and
ball bearings of angle-contact design for axial load
ensure a nominal service life up to 100.000 operating
hours. A hydraulically loaded balance piston reduces
axial loads and increases the designed service life of the
thrust bearings. In compressors of the series LT, lowwear friction bearings carry the radial loads of the rotor
shafts on a thin oil film without contact, whereas the
angle-contact ball bearings take the axial load.
Position indication
For positioning the hydraulic systems of the capacity control
and the Vi adjustment, a hermetic path sensor is used which
provides an output signal between 4 and 20mA.
03.2002/1
PHILOSOPHY OF SERIES
SCREW COMPRESSORS
Grasso
Refrigeration Division
Type
231
265
Series SH
321
SemiPacks
372
471
Series MC
544
690
Compact Screws
860
805
Series LT
1040
1290
High Performance
1640
1940
2296
Y
Z
2748
a
XA
3250
XB
b
4150
g
XC
4900
XD
d
5800
0
1000
2000
3000
4000
5000
6000
03.2002/1
PHILOSOPHY OF SERIES
SCREW COMPRESSORS
Grasso
Geschftsbereich
Kltetechnik
SH - SEMIPACKS
extremly high degree of component integration,
exclusively antifrictional bearings,
Vi- , partload control (PS - system).
type
231
164
265
188
321
228
372
264
MC - COMPACT-SCREW COMPRESSORS
high degree of component integration,
exclusively antifrictional bearings,
stepless Vi- , partload control (PS - system).
type
471
335
544
387
M*
690
490
N*
860
611
805
572
1040
739
1290
917
1640
1165
1940
1378
2296
1632
2748
1953
XA
3250
2309
XB
4150
2949
XC
4900
3482
XD
5800
4122
03.2002/1
PRODUCT NAME
Grasso
SCREW COMPRESSORS
Refrigeration Division
Name
(Z)
Series
Code letter
Series
Code letter
SH
C
D
E
G
231
265
321
372
LT
MC
H
L
M
N
471
544
690
860
P
R
S
V
W
Y
Z
XA
XB
805
1040
1290
1640
1940
2296
2748
3250
4150
4800
5800
XC
*)
50Hz power system; for a 60Hz system, multiply the values by 1.2.
XD
key number
1
Vi = 2.6
Vi = 3.6
Vi = 4.8
Vi = 5.5
Vi = variable
SH series
51
Vi = 2.6/4.8
stepped
52
Vi = 2.6/4.0
stepped
53
Vi = 3.2/4.8
stepped
Vi = 2.6...5.5
stepless
51
Vi = 2.2...4.0
stepless
52
Vi = 2.6...5.5
stepless
MC series
5
LT series
03.2002/1
PRODUCT NAME
Grasso
SCREW COMPRESSORS
Refrigeration Division
Booster application
61
Vi = 2.6
62
Vi = 3.6
Vi = 2.6
72
Vi = 3.6
Vi - variable
SH series
751
Vi = 2.6/4.8
stepped
752
Vi = 2.6/4.0
stepped
Vi = 2.6...5.5
stepless
Vi = 2.2...4.0
stepless
MC series
75
LT series
751
8
Vi = 2.6
82
Vi = 3.6
83
Vi = 4.8
Vi = 2.6...4.8
stepless
stepless
Vi = 2.6...5.5
Examples of designation
P - 61
Screw compressor 805m/h (P), Booster with an internal volume ratio Vi=2.6 (61)
C-2(E)
Screw compressor 231m/h (C), internal volume ratio Vi=3.6 (2), coupling housing with
coupling for KN7 225M - 75kW electric motor (E)
03.2002/1
PRODUCT NAME
Grasso
SCREW COMPRESSORS
Refrigeration Division
(Z)
output in kW
15
18,5
22
30; 37
ABB
160M 1LA5
160L
enclosure
sc type C/D
sc type E/G
IP 54
1LA5
180M 1LA6
1LA6
225M 1LA6
55
250M 1LA6
75
280S
90
280M 1LA6
200L
W/1
Speed controlled
1LA6
110
315S
132
315M 1LA6
150
1PL6186-4HL
1LA6
75, 90
250
SA2
110
250
MA2
280
SMA2
55
75
280
90
280
SMA
315
SA
132
315
SMA
15
IP 23
IP 55
SA
110
18,5
P160MG
IP 23
K
-
P160L
30
P180M
37
P180L
55
PLS200LP
75
P225M
90
P250S
110
P250M
132
P280M
A
15
18,5
03.2002/1
name
45
132
Leroy Somer
coupling type
LS 160M
IP 55
LS 160L
22
LS 180MT
30
LS 200LT
37
LS 200L
55
LS 250MP
75
LS 280 SP/MP
110
LS 315 SP/MP
T
-
PRODUCT NAME
Grasso
SCREW COMPRESSORS
Refrigeration Division
output in kW
coupling type
name
enclosure
sc type C/D
sc type E/G
IP 23
P
R
AEG
30
KN7 180M
(Schorch)
37
KN7 180L
45
KN7 200M
55
KN7 200L
75
KN7 225M
90
KN7 250S
110
KN7 250M
132
KN7 280M
22
KA7 180M
30
KA7 207L
37
KA7 200L
45
KA7 225M
55
KA7 250M
75
KA7 280S
90
KA7 280M
110
KA7 315S
132
KA7 315M
15
18,5
VEM
160 L
180 M
30
200LA
37
200LB
45
225M
55
250M
75
280S
90
280M
A
15
K11R 160MX2
IP 55
K11R 160 L2
22
K11R 180 M2
30
K11R 200 L2
37
45
K11R 225 M2
55
K11R 250 M2
75
K11R 280 S2
90
K11R 280 M2
110
K11R 315 S2
132
special request
IP 55
22
18,5
WEG
160 MB
IP 54
75
K11R 315 M2
225 S/M
IP 23
*) according to IEC standard 34-7; type IM B 35 (flange motor with mounting feet) may also be used.
03.2002/1
PRODUCT NAME
Grasso
SCREW COMPRESSORS
Refrigeration Division
coupling type
manufacturer
output in PS
name
USA
40
40HP - 286 TS
(Nema-face)
50
50 HP 324 TS
60
60 HP 326 TS
75
75 HP 364 /5 TS
100
125
USA
50
RAM Industries
60
(C-face)
75
enclosure
sc type C/D
sc type E/G
IP 23
D/1
R/1
D/2
R/2
E/ FES
S/ FES
100
125
150
03.2002/1
Grasso
SCREW COMPRESSORS
Refrigeration Division
compressor
type
theoretical
swept vol.
m/h
(0)
ZM/ZF
(1)
231
5/6
265
5/6
321
G
H
L
Vi-adjustment
Vi-Version
compressor
equipment
bearing
radial/ axial
oil
supply
drive
motor
(2)
(3)
PS2
1235678
(4)
(5)
(6)
(7)
W/W
PS2
1235678
W/W
5/6
PS2
1235678
W/W
372
471
5/6
PS2
12356789
W/W
5/6
PS0
123567
W/W
544
5/6
PS0
123567
W/W
690
5/6
PS0
123567
W/W
860
5/6
PS0
1235679
W/W
805
5/6
TS0
1234567
G/W
1040
5/6
TS0
1234567
G/W
E
E
1290
5/6
TS0
1234567
G/W
1640
4/6
TS0
123567
G/W
1940
5/6
TS0
1234567
G/W
2296
4/6
TS0
123567
G/W
E
E
2748
5/6
TS0
123567
G/W
XA
3250
5/6
TS0
123567
G/W
XB
4150
5/6
TS0
1234567
G/W
XC
4900
5/6
TS0
1234567
G/W
XD
5800
5/6
TS0
1234567
G/W
(0)
at 2940rpm (50Hz power system; for a 60Hz power system, multiply values by 1.2
(1)
ZM
ZF
(2)
PS
TS
(3)
1
2
3
4
5
6
7
8
9
Vi = 2.6
Vi = 3.6
Vi = 4.8
Vi = 5.5
Vi = variable
booster application
heat pump compressor
commercial refrigeration compressor
speed controlled refrigeration compressor
(4)
A
B
C
D
---- : underlined components are optional (operation with external pump is possible)
(5)
W
G
antifriction bearings
sleeve bearings
(6)
O
M
(7)
F
E
flange motor
motor and compressor installed separately
03.2002/1
LIMITS OF APPLICATION
Grasso
SCREW COMPRESSORS
Refrigeration Division
The tabulated data apply for single, two-stage and heatpump operation. The appropriate compressor model
design (1-7) should be selected for the particular
operating conditions *) Depending on the specific
operating conditions, there might occur reductions of
the limits given in the table due to the Compressor
Selection Programme COMSEL/GSCREW.
t0h
min
> - 60
bar (a)
max
< 28
te
max
< 120
min
> 1,5
bar
min
> 0,8
compressor type
maximum driving power (kW)
maximum nominal torque
maximum speed limits
compressor type
maximum driving power (kW)
maximum nominal torque
maximum speed limits
50 Hz
60 Hz
Nm
rpm
C/D
105
126
350
6.000
E/G
150
180
500
6.000
H/L
200
240
640
4.500
M /N
300
360
960
4.500
50 Hz
60 Hz
Nm
rpm
P
330
400
1060
3.600
R / S/ T
530
640
1700
3.600
V /W/ Y
900
1080
2900
3.600
Z / XA
1250
1500
4020
3.600
XB, XC, XD
1800
2160
5730
3.600
XE, XF
3000
3600
9500
3.600
Instructions:
Minimal over-heating on suction side: wet operation to be avoided.
The minimum compressor discharge temperature te must be sufficientlyabove the oil temperature for supply
to the bearings for compressor with sleeve bearings.
Limits for temperature differences will be considered in COMSEL/GSCREW
Gas pulsation protection required for 8 only.
SH and MC series: Minimal speed control in integrated oil pump 2000 min -1
Rotation direction: view to compressors driving shaft: clockwise
For p= p-po 4 bar is an external oil pump to be taken into consideration
For operation conditions with speeds differing from 50 or 60 Hz, the manufacturer should be contacted
Comments :
1.
For each individual application all conditions given in the tables should be taken into consideration and
adhered to.
2.
Should the given limit values be exceeded in any particular case, the manufacturer must be consulted.
3.
In addition to the application limits given in the tables, consider the operating conditions which must be
observed for the corresponding type of the compressor (e.g. start-up regime, oil pressure, oil quantity etc.).
4.
5.
Ensure that the oil viscosity will be 7...70 cSt at n 2950 min-1 for the oil supply to bearings. Take into
account the drop in viscosity due to refrigerant dissolved in the oil!
6.
Economizer operation between the 100% and 85% control slide positions.
07.2003/2
MAIN DIMENSIONS
SCREW COMPRESSORS
SH SERIES - SEMIPACKS, TYPES C, D
Grasso
Refrigeration Division
main
coupling housing
dimensions with coupling *)
l1
(overall length)
A; B
C; G
(mm)
888 [918]
918 [948]
l2
(mm)
351
381
l3
b1 (overall width)
(mm)
h1 (overall height)
(mm)
d1 (locating flange-)
(mm)
250
d2 (hole-circle-)
(mm)
300
(thread size)
(number of bolts)
381 [411]
(mm)
411 [441]
544
660
588
510
615
560
300
350
550
450
350
400
600
500
M 20
M 16
352 [362]
313 [324]
492
M 16
4
suction side
DN 80
discharge side
DN 65
supercharging
DN 25
refrigerant injection
DN 8
282 [293]
E; F
292 [303]
300 [310]
320 [330]
09/2001 Rev.2
Screws SH Series
MAIN DIMENSIONS
SCREW COMPRESSORS
SH SERIES - SEMIPACKS, TYPES C, D
FES DESIGN
Grasso
135
280
D1
257
110
51
350
450
25
285
190
492
H1
D2
Refrigeration Division
Main
dimensions
coupling housing
with coupling
Order No.
L1
(overall length)
Booster
High stage
250165:28D50
250175:28D50
High stage
special design
250174:28D50
(mm)
918 [948]
910 [940]
L2
(mm)
381
373
L3
(mm)
381 [411]
383 [413]
B1
(overall width)
(mm)
526
576
H1
(overall height)
(mm)
510
560
D1
(locating flange-)
(mm)
266,7
317,5
406,7
D2
(hole-circle-)
(mm)
228,6
279,4
355,6
(thread size)
(mm)
15,5
17,5
(number of bolts)
suction side
DN80
discharge side
DN65
supercharging
DN25
refrigerant injection
DN8
approx.weight, max.
[...]
(kg)
328 [338]
364 [374]
368 [378]
Screws SH Series
09/2001 Rev.2
MAIN DIMENSIONS
SCREW COMPRESSORS
SH SERIES - SEMIPACKS, TYPES E, G
Grasso
Refrigeration Division
main
coupling housing
dimensions with coupling *)
M; N
P; V
S; T
(mm)
975 [1004]
1005 [1034]
l2
(mm)
362
392
l3
b1 (overall width)
(mm)
h1 (overall height)
(mm)
d1 (locating flange-)
(mm)
250
300
d2 (hole-circle-)
(mm)
300
350
l1
(overall length)
(thread size)
(number of bolts)
432 [461]
(mm)
462 [491]
620
675
595
615
670
350
450
550
400
500
600
M16
M20
suction side
DN 100
discharge side
DN 65
supercharging
DN 25
refrigerant injection
DN
412 [423]
418 [429]
423 [433]
8
442 [452]
438 [448]
461 [472]
09/2001 Rev.2
Screws SH Series
MAIN DIMENSIONS
SCREW COMPRESSORS
SH SERIES - SEMIPACKS, TYPES E, G
FES DESIGN
Grasso
Refrigeration Division
main
dimensions
L1
coupling housing
with coupling
order no.
(overall length)
Booster
High stage
250166:28G50
250177:28G50
High stage
special design
250176:28G50
(mm)
1005 [1034]
997 [1026]
L2
(mm)
392
384
L3
(mm)
395 [424]
397 [426]
B1
(overall width)
(mm)
545
595
H1
(overall height)
(mm)
510
560
D1
(locating flange-)
(mm)
266,7
317,5
406,7
D2
(hole-circle-)
(mm)
228,6
279,4
355,6
(thread size)
(mm)
15,5
17,5
(number of bolts)
suction side
DN100
discharge side
DN65
supercharging
DN25
refrigerant injection
DN8
approx.weight, max.
(kg)
451 [461]
509 [519]
513 [523]
Screws SH Series
09/2001 Rev.2
MAIN DIMENSIONS
SCREW COMPRESSORS
MC SERIES, TYPES H, L, M, N
Grasso
Refrigeration Division
Type
471
544
690
860
b1
425
510
b2
350
425
b3
109
138
b4
132
150
dm
18
22
h1
537
646
h2
215
270
h3
36
50
h4
23
26
l1
938
974
1094
1145
l2
350
386
406
457
l3
165
219
l4
245
296
l5
219
260
l6
60
55
l7
75
95
weight
366
381
660
690
nominal sizes
suction side
NB 125
NB 150
of connections
discharge side
NB 80
NB 100
supercharging
NB 32
NB 40
00.09
Screw MC Series
MAIN DIMENSIONS
SCREW COMPRESSORS
LT SERIES - TYPES P, R, S, T, V, W, Y, Z, XA, XB, XC, XD
Grasso
Refrigeration Division
l4
l
b
1
female
rotor
male
rotor
suctio
side
connectio
superfee
discharg
side
h4
e
liqui
injectio
**
5
type
805
1040
1290
1460
1640
1940
2296
b1
600
660
750
d1
26
26
26
d2
e1
60 h6
375
e2
500
566
e3
160
176,3
200
e4
170
195
200
418
60 h6
485
525
480
80 h6
535
e5**
250
283
300
h1
525
570
670
h2
290
330
350
h3
50
70
70
h4
110
130
145
l1
817
l2
272
347
l3
95
115
l4
65
45
965
1085
1125
1040
1095
130
105
HR*
HR*
HR*
DN 150
DN 175
DN 250
sizes of
discharge side
DN 100
DN 100
DN 150
connec-
superfeed
DN 32
DN 40
DN 65
tions
liquid injection
DN 15
DN 15
DN 15
598
890
960
130
100
driving shaft
1160
360
suction side
nominal
600
600
1060
1134
1195
1283
* male rotor
** position discharge connection
07.2003/2
Screws LT Series
MAIN DIMENSIONS
SCREW COMPRESSORS
LT SERIES - TYPES P, R, S, T, V, W, Y, Z, XA, XB, XC, XD
Grasso
Refrigeration Division
l4
l
b
1
female
rotor
male
rotor
suction
side
connection
superfeed
discharge
side
h4
e
4
2
liquid
injection
**
5
type
XA
XB
XC
XD
2748
3250
4150
4900
5800
b1
760
900
26
d1
80 h6
d2
e1
630
705
650
90
717
e2
660
800
e3
220,3
272
e4
230
278
e5**
353
443
h1
700
850
h2
400
495
h3
70
90
h4
140
195
l1
1315
1390
1387
1444
l2
435
462
l3
128
122
85
120
driving shaft
l4
HR*
HR*
nominal
suction side
DN 250
DN 300
sizes of
discharge side
DN 150
DN 200
DN 100
DN 125
DN 15
DN 18
connections superfeed
liquid injection
weight: max [kg]
1670
1740
2400
2560
800
1527
2650
* male rotor
** position discharge connection
Screws LT Series
07.2003/2
MAIN DIMENSIONS
SCREW COMPRESSOR
SERIES LT TYPES XE, XF
Grasso
Refrigeration Division
l t1
l t4
Economizer
port
Liquid
injection
MR
Suction
side
l t3
h t2
Discharge
side
h t4
h t3
h t1
d t2
FR
b t1
e t3
e t4
e t2
e t5
d t1
type
XE
XF
7170
8560
b1
1078
d1
33
d2
e1
905
800
e3
320
e4
255
e5**
430
h1
980
h2
580
h3
95
h4
220
1614
1713
l2
500
l3
124
l4
130
driving shaft
Male rotor
nominal
suction side
DN400
sizes of
discharge side
DN250
connections superfeed
DN150
Oil injection
DN80
liquid injection
DN25
l t2
110 h6
806
e2
l1
**
e t1
Main oil
injection
3500
3800
07.2003/ 0
040_440gbr.doc - 1/1
Grasso
SCREW COMPRESSORS
Refrigeration Division
Connection
Remarks
Suction
Discharge
Economizer port
Series LT :
140 m
N.B:
Liquid (refrigerant or oil) can lead to destruction of the filter at the suction and economizer connection.
07.2003/2
Grasso
SCREW COMPRESSORS
Refrigeration Division
type
oil-
poil
viscosity
filter
pump
l/min
bar
mm/s
function, purpose
min
functional oil1)
C, D,
without
max
see instructions
min
max
max
min
max
p+3,55)
80
70
154)
p+3,55)
80
70
15
p2,5
p+3,55)
100
70
140
p+0,5
p+5,0
80
70
15
p2,5
p+3,55)
100
70
60
80
70
15
5)
p+0,5
p-1,0
E, G
functional oil2)
H, L,
p+0,55)
without
see instructions
M, N
P, R,
oil injection
without
functional oil3)
with
p-2,5
see instructions
S, T
oil injection
capacity control
balancing piston,
without
with
without
10
20
6)
Room 1
p+0,5...5,0
Room 26)
p0+7 bar
Room 36)
p1,5
100
70
15
p+0,5
p+5,0
80
70
15
p2,5
p+3,55)
100
70
140
80
70
15
heat pump
functional oil3)
V, Y
with
see instructions
oil injection
without
capacity control
with
Room 16)
p+0,5...5,0
without
15
25
p1,5
100
70
15
p+0,5
p+5,0
80
70
15
p2,5
p+3,55)
100
70
140
p1,5
100
70
15
80
70
15
heat pump
W, Z,
XA, XB
functional oil3)
XC, XD
oil injection
without
balancing piston,
without
20
30
with
XE, XF
with
see instructions
heat pump
capacity control 7)
Room 16)
p+0,5...5,0
Room 26)
p0+7 bar
Room 36)
poil
1)
functional oil
for bearing, shaft seal, balancing piston, oil injection, internal oil pump, capacity control and Vi-adjustment
2)
functional oil
for bearing, shaft seal, balancing piston, internal oil pump, capacity control and Vi-adjustment
3)
functional oil
for bearing, shaft seal, balancing piston (+ capacity control, and Vi-adjustment for types Z, XA, XB, XC, XD)
4)
5)
6)
7)
for external oil supply of capacity control (operation without integrated solenoid valve block)
07.2003/4
Refrigeration Division
Hints:
1. Use the selection programme Kabcom/GSCREW to choose the screw compressor. It gives additional
information about the oil circuit of the compressor and application limits of the compressors belonging to the
series SH and MC with integral oil pump. The selection programme specifies for which operating conditions an
external oil pump for the functional oil circuit will be required (External oil pump required).
2. Depending on the operating conditions of the compressor, the oil flow rates required for safe compressor
operation are shown in the selection programme Kabcom/GSCREW. The oil pump must have a delivery rate
reaching at least the value 1.5 x functional oil flow.
In the Kabcom/GSCREW selection programme, the terms
functional oil flow
total oil flow (with additional oil injection, if required)
are used.
3. Series LT
Hydraulic chambers for capacity control and Vi-adjustment:
1, 2
07.2003/4
ELECTRIC CONNECTIONS
Grasso
SCREW COMPRESSORS
Refrigeration Division
connected load
position sensor
position sensor
valve block 2
valve block 4
24V (DC)
24V (DC)
24V DC
24V AC
48V AC
110V AC
230V AC
output signal
4-20 mA
20-4 mA
-
function
screw compressor
type
H, L, M, N, P,
R, S, V, Y, Z, XA,
XB, XC, XD, XE, XF
H, L, M, N
C, D, E, G
+24V DC
4 - 20 mA
0V (ground)
output signal:
For all SV types
control slide min. pos.:
control slide max. pos.:
4mA1)
20mA
4mA
20mA
SOLENOID VALVES
Valve block 2 connection diagram
Y6
Y5
Y4
07.2003/2
Y1
Y3
ELECTRIC CONNECTIONS
Grasso
SCREW COMPRESSORS
Refrigeration Division
Y1 and Y4 open
Y2 and Y3 closed
Y2 and Y3 open
Y1 and Y4 closed
Y6 open
Y5 closed
Vi increase:
Y5 open
Y6 closed
LT Series
secondary slide
moves in direction suction side:
secondary slide
moves in direction discharge slide
Y5 open
Y6 closed
Y5 open
Y6 closed
Instructions:
The control of the magnetic valve blocks is outlined in data sheet 635014 Compressor Control.
07.2003/2
Grasso
SCREW COMPRESSORS
Refrigeration Division
INSTALLATION CONDITIONS:
compressor mounting surfaces
ambient temperature
18C*... 50 C
Vmax:
CG=
HN=
PS =
V - XA =
XB, XC, XD =
2,0 mm/s
2,5 mm/s
3,0 mm/s
3,5 mm/s
4,0 mm/s
H, L, M, N
R, S
V, W, Y, Z, XA
XB, XC, XD
force
F [N]
2500
3000
5000
5500
6000
7000
moment
M [Nm]
1200
1800
2500
3000
3500
4000
F [N]
2000
2500
4000
4500
5000
3500
M [Nm]
1000
1500
2000
2500
3000
3500
500
700
900
900
1300
1500
axial force
200
300
400
400
600
800
C, D, E, G
[N]
compressor type
dB (A)
82
83
84
85
86
87
88
88
88
compressor type
dB (A)
XA
XB
XC
XD
89
90
91
91
92
93
94
96
96
96
vibration:
compressor type
C, D, E, G, H, L, M, N, P, R, S, W, Z, XA, XB, XC, XD
main exciting
frequencies at
3000 rpm
(3600 rpm)
f1
f2
f3
f4
f5
Hz
Hz
Hz
Hz
Hz
50
100
250
500
6000
(60)
(120)
(300)
(600)
...8000
V, Y
50
(60)
100 (120)
200 (240)
400 (480)
5000 ...7000
structure-borne noise
Critical torsional natural frequency
(with consideration to the total mass moment of inertia of rotor pair)
Type
C N,
P, R, S
03.2002/1
XB
XC
XD
XE
XF
174,6
115,4
97,6
90,8
84,0
77,1
70,9
COUPLING REQUIREMENTS
Grasso
SCREW COMPRESSORS
Refrigeration Division
The following requirements must be met when using a coupling not supplied by Grasso:
parameter
compressor type
C /D
E/G
H/L
M/N
R/S
V/W/Y
Z/XA
XB, XC,
XD
maximum driving
power (60 Hz)
kW
102
145
210
320
300
480
760
1080
1800
nominal torque
Nm
280
390
570
865
810
1300
2050
2850
5730
maximum starting
torque
Nm
700
980
1450
2150
2050
3250
5150
7200
14500
maximum speed
min-1
3600
maximum dynamic
mNm
unbalance allowable
500
700
900
1300
1500
200
300
400
600
800
mm
40-0,02-0,04
50h6
60h6
80h6
90
mm
60+5
70+5
70+5
80+5
90+5
permissible
radial force FR 1)
permissible
axial force FA
shaft diameter
compressor
distance between
shaft ends
compressor/motor
1)
Maximum forces which are allowed to act on the compressor shaft end. The coupling must be selected and
aligned in such a way that these forces are not exceeded.
Further requirements:
design of the compressor shaft end:
direction of rotation:
03.2002/1
STARTING CONDITIONS
Grasso
SCREW COMPRESSORS
Refrigeration Division
03.2002/1
OPERATIONAL MONITORING
Grasso
SCREW COMPRESSORS
Refrigeration Division
The following parameters must be recorded and monitored during operation of the compressor:
parameter
to be recorded
purpose
minimum position
Vi-adjustment
suction pressure
discharge temperature 2)
protection of compressor
protection of compressor
discharge pressure
1)
2)
00.09
Grasso
Refrigeration Division
Special refrigerator oils must be used for refrigerant compressors. The selection of the type of oil not only
depends on its viscosity and its chemical properties, but also on the operating conditions of the respective
refrigeration plant.
The oils given in the table can be used for screw compressors. The choice depends on the refrigerant, viscosity (at
least 7cSt for oil temperature before entering the compressor), vaporisation temperature (pour point) and
requirement made of the oil separation behaviour (flash point, viscosity or specially treated oils*
hydrotreated).
The oils in Table 1 are recommended especially if minimum oil carry over is important.
Table 1:
Lubricating oils for R717 (Ammonia)
Recommended oils
Manufacturer
Oil type
Basis
Viscosity at
40C in cSt
Flash point in
C
Pour point
in C
Comment
CPI
CP 1009-68
M*
68
226
- 40
hydrotreated,
only for R717
Petro Canada
Reflo 68A
M*
58
236
- 42
hydrotreated,
only for R717
Table 2:
Lubricating oils for R22 and R717 (Ammonia)
Permissible oils
Manufacturer
Oil type
(see footnote)
Basis
Viscosity
at 40C in cSt
Flash point
in C
Pour point
in C
Comment
Castrol
Icematic 299
56
180
- 34
Castrol
Icematic 2294
PAO
69
233
- 60
for R717
CPI
CP-4600-46
PAO
46
268
- 51
only
ELF
Elfrima FR 46
46
171
- 37
ESSO
Zerice 46
46
204
- 41
ESSO
Zerice S46
AB
46
172
- 36
FUCHS-DEA
Reniso S68
AB
68
190
- 33
MOBIL
SHC 226E
PAO
67
266
- 54
MOBIL
SHC 326
AB+PAO
61
211
- 54
MOBIL
SHC 426
AB
65
176
- 36
MOBIL
64
202
- 40
MOBIL
44
187
- 50
Shell
44
195
- 39
Shell
65
205
- 36
Shell
Shell Clavus 46
44
195
- 39
Shell
Shell Clavus 68
65
205
- 36
TEXACO
Capella Premium
M*
67
262
- 42
hydrotreated,
only for R717
03.2002/2
Grasso
Refrigeration Division
Table 3:
Lubricating oils for R134a; R404A; R407C; R410A; R507
Permissible oils
Manufacturer
Oil type
(see footnote)
Basis
Viscosity at
40C in cSt
Flash point in
C
Pour point in
C
Castrol
Icematic
SW 68
68
250
- 39
Castrol
Icematic
SW 100
100
255
- 30
Castrol
Icematic
SW 220
220
290
- 26
CPI
Solest 68
64
266
- 43
CPI
Solest 120
125
262
- 27
CPI
Solest 220
216
271
- 27
FUCHS-DEA
Reniso Triton
SE 55
53
270
- 51
FUCHS-DEA
Reniso Triton
SEZ 80
80
275
- 39
FUCHS-DEA
Reniso Triton
SEZ 100
91
288
- 39
FUCHS-DEA
Reniso Triton
SE 170
170
260
- 24
Shell
Shell Clavus
R 68
64
250
- 54
Shell
Shell Clavus
R 100
93
280
- 45
MOBIL
EAL 68
63
254
- 43
MOBIL
EAL 100
96
250
- 37
Comment
Table 4:
Lubricating oils for 290 (Propan)
Permissible oils
Manufacturer
Oil type
(see footnote)
Basis
Viscosity
at 40C in cSt
Flash point in
C
Pour point
in C
Shell
Madrela Oil T
PAG
185
260
-30
CPI
CP-1516-150
PAG
153
260
-34
Mobil
Glygoyle 22
PAG
161
229
-41
Comment
Alkylbenzene
Polyolester
Mineral oil
Mineral oil with special treatment
(hydrotreated oil)
PAO
PAG
Polyalphaolefin
Polyalkylglycol
03.2002/2
Grasso
Refrigeration Division
Table 5:
Use of O-ring elastomers in screw-type compressors dependent on refrigerant and lubricant:
Oil
M*
AB
PAO
AB/PAO
PAG
R717 (Ammonia)
CR
CR1)
CR
HNBR
CR
HNBR
R22
CR
CR
HNBR
HNBR
Refrigerant
Note:
The pour point describes the cold fluidity of an oil and represents a non-guaranteed guide value for the
minimum evaporating temperature.
[ The pour point is defined as the temperature at which the fluidity of an oil decreases to an extent that it
does not leave a jar within 5 sec under certain conditions.]
Compressors are equipped with suitable elastomers at the sealing point, which are selected dependent on the
refrigerant and lubricant. (Table 4)
When selecting the type of oil, the compatibility of the sealant material used in the compressor for o-rings
(elastomer quality) must be taken into consideration in addition to the refrigerant. (see Table 4)
Not all the listed oil types can be used for an existing compressor. Allocation of the oil type dependent on the
elastomer used is necessary, even for the same refrigerant.
Oil types are not always compatible with each other (not miscible).
Changing from one oil type to another can lead to disruptions in the operation of the compressor and to
leakages at the sealing points. The compressor manufacturer should always be contacted before changing the
oil type.
In exceptional cases, oils other than those listed in the table can be used, if the compressor manufacturer is
contacted first.
Attention:
The lubricant viscosity range downstream of the compressor given in data sheet 040 510e must always be
observed. At the same time, it must be noted that refrigerant/oil combinations are possible in which,
dependent on the pressure and temperature in the oil reservoir (oil separator), the refrigerant dissolves in the
oil. This leads to a reduction of the viscosity of the pure oil and to the formation of foam when the solution
equilibrium is altered due to pressure reduction or temperature increase.
In this case, the oil must be cooled by a minimum temperature difference, which is calculated in the
compressor selection programme Comsel for the given operating conditions (11 to 14 K dependent on the
refrigerant and operating condition). The compressor may only be operated if the oil entry temperature is
complied with in accordance with the compressor selection programme.
The oil separation behaviour of the types of oil given in the Table can vary greatly (e.g. influence of oil vapour
pressure, oil viscosity, solubility, final compression temperature).
03.2002/2
Grasso
SCREW COMPRESSORS
HINTS FOR SELECTION OF REFRIGERATION OIL
Refrigeration Division
The properties of the refrigeration oil have an influence on the operation of refrigerating plants with oil-flooded
screw compressors, as it cannot be excluded that residues of the refrigeration oil get into the refrigerant circuit
despite of highly effective oil separators. For this reason, when selecting the oil consider besides
a sufficient lubricity of the oil at the bearing points of the screw compressor (minimum oil viscosity with
consideration of the solubility of refrigerants in oil depending on both the pressure and temperature),
the vapour pressure of the oil for a proper separation behaviour in the oil separator,
a sufficient fluidity of the oil at both the evaporating and suction temperature
the requirements upon the miscibility of the liquid phases of the refrigerant and the oil (miscibility gap).
The refrigerant used, the operation conditions and the specific plant design determine the required characteristics
of the refrigeration oil.
At present, five different base oil brands are used:
1. Mineral oils for ammonia and R22
2. Polyalphaolefins for ammonia
3. Alkyl benzene for ammonia and R22
4. Polyglycol (PAG-oil) for ammonia
5. Ester oil for R 404A, R 134a and R 507 as well as other new refrigerant blends such as R 410A or R 407C
Besides the pure base oil components there are also used blends of mineral oil and alkyl benzene or of
polyalphaolefin and alkyl benzene.
The characteristics of the refrigerants with relation to the oils mentioned differ greatly.
Two basic requirements are placed upon the working media combination of refrigerant and refrigeration oil:
a. Minimum oil viscosity of 7 cSt at the compressor inlet with consideration for the refrigerant solubility in oil
and
b. Miscibility of both liquid phases of a certain portion of the oil (ab. 1 to 2 %) and the refrigerant.
Besides the requirement of a sufficient viscosity of the lubricating oil, the discharge temperatures in the
compressor must be high enough to enable a subcooling of the refrigerant-laden oil by at least 10 K in order to
prevent foaming in the compressor in case of decrease in pressure and/or increase in temperature, before the oil
gets to the bearing points.
The basic requirement b) is not met by mineral oil, alkyl benzene and polyalphaolefin in connection with
ammonia, as there exists a miscibility gap of 100 %, and neither a solubility of the refrigerant vapour in the oil
nor a miscibility of liquid phases is given. Nevertheless these oils are preferably used in NH3-plants. Oil fine
separation stages prevent greater portions of the oil from getting into the refrigerant circuit.
The base oil versions mentioned will bring about differing oil carry-over rates as the flash points of the oils cited
differ greatly from each other (lowest flash point of alkyl benzene at ab. 160 C, highest flash point of
polyalphaolefin considerably above 200 C).
Although the fluidity of the oil is characterized by the pour point indicated by the oil manufacturers, the base oil
brands mentioned above feature different VT-characteristics so that at the same initial viscosity of say 68 cSt,
there may arise differences in viscosity at low temperatures in the evaporator in the range of ab. 1500 and
20000 cSt at 20C.
00.09/ 0
Grasso
SCREW COMPRESSORS
HINTS FOR SELECTION OF REFRIGERATION OIL
Refrigeration Division
00.09/ 0
Grasso
SCREW COMPRESSORS
HINTS FOR SELECTION OF REFRIGERATION OIL
Refrigeration Division
00.09/ 0
SCREW COMPRESSORS
HINTS FOR SELECTION OF REFRIGERATION OIL
Grasso
Refrigeration Division
TABLE
REFRIGERANT OIL COMPATIBILITY
Ammonia
(NH3)
R22
R134a
R404A
R507
Polyalphaolefins
(PAO)
Alkyl benzene
(AB)
Polyglycol
(PAG)
Ester oil
M + AB
PAO + AB
00.09/ 0
Grasso
Refrigeration Division
I.
A
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Oil pump
P+I-No
intern
SM11
for booster / for refrigeration and a.c. with low condending temperature
(external oil pump for functional oil supply only)
extern
SM12
intern
SM13
extern
SM14
intern
SD11
for booster / for refrigeration and a.c. with low condending temperature
(external oil pump for functional oil supply only; 2 oil stop valves each
compressor)
extern
SD12
for booster/ for refrigeration and a.c. with low condending temperature
(external oil pump for whole oil supply; 1 oil stop valve each compressor)
extern
SD13
intern
SD14
Oil pump
P+I-No
II
as high pressure stage (external oil pump for functional oil supply only)
extern
SM21
extern
SM22
Remarks: Oil Pump - intern means: oil pump is a part of the screw compressor
- extern means: oil pump is a part of the package
The P & I diagramms have to be used for all permitted refrigerants including ammonia and all permitted oils.
For use of the combination of Ammonia and PAG-oil please contact Grasso R.T. in Berlin.
Screw compressors for DuoPacks are suitable for use in Multi-Packages with more than 2 screw compressors
The external oil pump has to supply functional oil with a pressure of pk+0,5 bar < poil < pk+2,5 bar.
The delivery flow of external oil pump has to be selected depending on compressor size (see compressor
selection program) and depending on the number of compressors in a package. The compressor selection
program calculates the oil volume flow for 1 screw compressor.
The integrated oil pump delivers 3 l/min only and supplies it to the hydraulic system (solenoid valve block);
the oil pressure of the integrated oil pump is limited by means of a integrated oil pressure control valve to 6
bar over pressure of functional oil.
Screw compressors for heat pump application are equipped with one side acting thrust bearings. It is not
allowed to use an external oil pump in screw compressors series SH and MC for heat pump application.
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
basic plate
X2
R
C
oil supply
cooled oil
to oil filter
Screw
compressor
oilmanagement block 1
check valve
functional oil
H
L
X1
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SM12
SERIES SH
MONOPACK, SINGLE STAGE, EXTERNAL OIL PUMP
cooled oil
p
Package
X2
R
C
oil supply
to oil filter
closing stopper
injected oil
Screw
compressor
functional oil
oilmanagement block 1
L
basic plate
X1
p
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SM13
SERIES SH
MONOPACK, HEAT PUMP, INTERNAL OIL PUMP
uncooled oil
Package
functional oil
X2
R
C
oil supply
to oil filter
closing stopper
injected oil
Screw
compressor
functional oil
H
L
oilmanagement block 1
Z
basic plate
X1
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SM14
SH SERIES
MONOPACK, DX CHILLER, EXTERNAL OIL PUMP
cooled oil
Package
X2
R
C
oil supply
to oil filter
Closing stopper
Screw
compressor
functional oil
discharge housing
basic plate
functional oil
shaft seal
N
L
Closing expander
X1
oilmanagement block 1
closing stopper
p
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SD11
SERIES SH
DUO PACK, SINGLE STAGE/HIGH STAGE, INTERNAL OIL PUMP
X2
basic plate
oilmanagement block 2
R
C
oil supply
cooled oil
to oil filter
injected oil
functional oil
Screw
Compressor
check valve
X1
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SD12
SERIES SH
DUO PACK, EXTERNAL OIL PUMP, SINGLE STAGE, BOOSTER
solenoid stop valve
Package
X2
cooled oil
R
C
oil supply
Injected oil
Screw
compressor
functional oil
closing stopper
L
basic plate
oilmanagement block 2
X1
p
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SD13
SERIES SH
DUO PACK, EXTERNAL OIL PUMP, SINGLE STAGE
Package
K
X2
cooled oil
R
oil supply
C
solenoid stop valve
injected oil
Screw
compressor
functional oil
basic plate
oilmangement block 2
X1
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SD14
SERIES SH
DUO PACK, INTERNAL OIL PUMP, HEAT PUMP
uncooled oil
measuring oil pressure
behind filter
Package
functional oil
X2
R
C
injected oil
to oil filter
injected oil
Verdichter
oil flow control valve
injected oil
functional oil
H
ldruckRegulierventil
Z
oilmanagement block 2
X1
closing stopper
06.10.00/ 0
basic plate
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SM21
SERIES SH
MONOPACK, TWO STAGE/HIGH PRESSURE STAGE, EXTERNAL OIL PUMP
external oil pump
Package
K
X2
cooled oil
R
C
oil supply
closing stopper
injected oil
Screw
compressor
functional oil
oilmanagement block 1
L
basic plate
X1
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM SM22
SERIES SH
MONOPACK, TWO STAGE/BOOSTER, EXTERNAL OIL PUMP
cooled oil
Package
external oil filter
X2
R
C
oil supply
injected oil
Screw
functional oil
oilmanagement block 1
L
basic plate
X1
06.10.00/ 0
closing stopper
Grasso
Refrigeration Division
I.
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Oil pump
P+I-No
intern
MM11
for booster / for refrigeration and a.c. with low condensing temperature
(external oil pump for functional oil supply only)
extern
MM12
intern
MM13
extern
MM14
intern
MD11
for booster / for refrigeration and a.c. with low condensing temperature
(external oil pump for functional oil supply only;
2 oil stop valves each compressor)
extern
MD12
intern
MD13
Oil pump
P+I-No
II
as high pressure stage (external oil pump for functional oil supply only)
extern
MM12
extern
MM21
Remarks: Oil Pump - intern means: oil pump is a part of the screw compressor
- extern means: oil pump is a part of the package
The P & I diagramms have to be used for all permitted refrigerants including ammonia and all permitted oils.
For use of the combination of Ammonia and PAG-oil please contact Grasso R.T. in Berlin.
Screw compressors for DuoPacks are suitable for use in Multi-Packages with more than 2 screw compressors
The external oil pump has to supply functional oil with a pressure of pk+0,5 bar < poil < pk+2,5 bar.
The delivery flow of external oil pump has to be selected depending on compressor size (see compressor
selection program) and depending on the number of compressors in a package. The compressor selection
program calculates the oil volume flow for 1 screw compressor.
The integrated oil pump delivers 9 l/min only and supplies it to the hydraulic system (solenoid valve block);
the oil pressure of the integrated oil pump is limited by means of a integrated oil pressure control valve to 6
bar over pressure of functional oil.
Screw compressors for heat pump application are equipped with one side acting thrust bearings. It is not
allowed to use an external oil pump in screw compressors series SH and MC for heat pump application.
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MM11
SERIES MC
MONOPACK, SINGLE STAGE, INTERNAL OIL PUMP
oil supply
injectedl oil
injected oil
cooled oil
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MM12
SERIES MC
MONOPACK, SINGLE STAGE, EXTERNAL OIL PUMP
oil filter
(0,5...2,5 bar)
Package
cooled oil
Package
injected oil
oil supply
injectedl oil
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
S
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MM13
SERIES MC
MONOPACK, HEAT PUMP; INTERNAL OIL PUMP
uncooled oil
measuring oil pressure
behind filter
Package
external oil filter injected oil
cooled oil
oil supply
injectedl oil
injected oil
D
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MM14
SERIES MC
DX CHILLER, EXTERNAL OIL PUMP
Package
cooled oil
injected oil
check valve
oil supply
injected oil
Screw
compressor
C2
Functional oil discharge
housing
functional oil
C1
E
closing expander, only types H and L
S
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MD11
SERIES MC
DUO PACK, SINGLE STAGE/HIGH PRESSURE STAGE, INTERNAL OIL PUMP
cooled oil
Package
injected oil
D
oil supply
injectedl oil
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MD12
SERIES MC
DUO PACK, SINGLE STAGE, EXTERNAL OIL PUMP
oil filter
cooled oil
Package
solenoid stop valve
injected oil
oil supply
injectedl oil
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
S
p
06.10.00/0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MD13
SERIES MC
DUO PACK, HEAT PUMP, INTERNAL OIL PUMP
uncooled oil
measuring oil pressure
behind filter
Package
uncooled oil
cooled oil
oil supply
injectedl oil
injected oil
D
Screw
compressor
C2
oil supply
functional oil
functional oil
C1
06.10.00/ 0
P + I DIAGRAMS
SCREW COMPRESSOR
SERIES SH AND MC
Grasso
Refrigeration Division
P + I DIAGRAM MM21
SERIES MC
MONOPACK, TWO STAGE/BOOSTER, EXTERNAL OIL PUMP
Package
cooled oil
oil flow control check valve
injected oil
Screw
compressor
C2
functional oil
(discharge pressure)
functional oil
C1
E
S
p
closing stopper
06.10.00/0
OVERALL CONCEPT
Grasso
Refrigeration Division
OVERALL CONCEPT
SCREW COMPRESSORS
SH SERIES, TYPES C, D, E, G
Brief Description
Design Features
03.2002
AISH02-1_gbr.doc - 1/3
OVERALL CONCEPT
Grasso
Refrigeration Division
BRIEF DESCRIPTION
Screw compressors of oil-flooded construction with
continuously variable capacity control and an
adjustable Vi-volume ratio. The compressors are
compactly designed and have the following integrated
subassemblies:
Centering flange
Check valve suction side
Suction filter
Solenoid valves for capacity control and Vi-Adjustment
Oil filter
Check valve discharge side
Overflow valve
Oil pump
Overflow valve
The corresponding design can be seen from the List of
Parts supplied with the compressor concerned.
AISH02-1_gbr.doc - 2/3
03.2002
OVERALL CONCEPT
Grasso
Refrigeration Division
DESIGN FEATURES
ADDITIONAL CONNECTIONS:
GAUGE CONNECTIONS
For measuring the temperature and pressure on
the suction and discharge side and of the oil system
compressor drive motor
suction filter
coupling
housing
oil connection
solenoid valve block
for Vi-adjustment
check valve
oil filter
check valve
suction nozzle
Shaft sealing
Bearing lubrication
overflow valve
Oil pump
Partial compensation of the axial forces
Oil injection into the working area
Solenoid valve on oil connection (special design)
discharge nozz
03.2002
AISH02-1_gbr.doc - 3/3
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
DESCRIPTION OF DESIGN
SCREW COMPRESSORS
SH SERIES, TYPES C, D, E, G
02.04.02/ 0
AISH03-1_gbr.doc - 1/9
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
ROTORS
COMPRESSOR CASING
The casing is made of grey cast iron and designed in
two parts. It consists of a rotor suction casing and a
discharge casing, and it has vertical parting joints. The
discharge casing is sealed off by the covering flange.
The connection flange on the suction side is arranged
vertically on the female rotor side of the compressor
and the connection flange on the discharge side is
arranged horizontally. A second outlet on the
discharge side (on the female rotor side) with a vertical
connection flange is optionally available.
The casing parts and the covers and flanges located in
the casing are sealed with O-rings. Screw-plugs are
provided for oil drainage.
Covering flanges with guide surfaces for the Vi-slide
are attached to the front wall of the working area on
the suction side. The axial outlet opening is integrated
in the front wall of the working area on the discharge
side.
Connections on the compressor casing allow measurement of temperature and pressure on the suction and
discharge side and of the oil system.
AISH03-1_gbr.doc - 2/9
02.04.02/0
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
SHAFT SEALING
The driven male rotor is sealed on the shaft bushing on
the suction end by means of an oil-sealed mechanical
contact seal. This seal has a balanced design so as to
achieve a maximum service life.
In the standard design, the counter ring arranged in
the cover is made of a special grey cast iron alloy, and
the elastic seal ring rotating with the shaft is made of
antimony-bound hard carbon. An O-ring takes over the
secondary sealing between the slide ring and the shaft.
For extreme loads and on customers request, there
are available special designs of shaft seals featuring
high-quality mating materials for both the seal- and
counter ring (e.g. silicon carbides, hard metals, special
hard carbons).
A suction side
B discharge side
02.04.02/ 0
AISH03-1_gbr.doc - 3/9
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
control edge
Vi-slide
control slide
bypass opening
bypass
opening
outlet
opening
control edge
control slide
Vi-slide
Vi-slide
control slide
AISH03-1_gbr.doc - 4/9
02.04.02/0
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
02.04.02/ 0
stop sleeve
AISH03-1_gbr.doc - 5/9
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
120
100
80
60
40
20
0
0 2 4 6 8 10 12 14 16 18 20 22
Output signal [mA]
AISH03-1_gbr.doc - 6/9
02.04.02/0
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
OIL FILTER
The compressor is equipped with an integrated oil
filter. The oil filter space is arranged transversely
beneath the control slide. Oil is delivered to the
compressor via the base plate of the oil supply system
(male rotor side).
A partial flow is taken from the filter space and
conducted into the rotor working space for cooling,
lubrication and sealing (cooling oil). A second partial
flow is required to lubricate the bearings and to
activate the hydraulic device of the Vi-adjustment
(bearing oil).
Both partial oil flows discharged from the filter
chamber firstly enter the oil filter lid again which in the
standard design houses two check valves and one
control valve for the cooling oil (figure 6). These partial
flows are then conducted from the oil filter cover to
the consumption points via internal oil drainage holes
in the compressor casing. This arrangement allows the
oil filter space to be separated from the remaining
compressor space when changing the filter.
check valve
243
cooling oil
bearing oil
160
assembly cover
X2
oil inlet
C
105
86
regulating valve
132
base plate of the
oil supply system
106
119
oil filter insert
02.04.02/ 0
AISH03-1_gbr.doc - 7/9
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
OIL PUMP
The oil of the oil pump is required to activate the
hydraulic device of the capacity control.The oil pump is
flanged at the frontage of the rotor casing.The female
rotor drives the oil pump. A partial flow from the filter
space is conducted via external pipe to the suction side
of the oil pump. The oil from the discharge side of the
oil pump enter the solenoid valve block of the capacity
control via second external pipe.
A overflow valve under the solenoid valve block
controls the pressure of the pump and conducts the
excess oil to the internal oil system of the compressor.
The pressure transmitter for measuring the pressure of
the oil pump is installed at the solenoid valve block.
P oil pump
Po
MIN
MAX
The hydraulic spaces of capacity control and Viadjusting device are connected to the oil system of the
oil pump or to the compressor suction space
alternately via the solenoid valve blocks (Figure 7).
The valve blocks are screwed to a flat surface of the
casing fitted with boreholes which serve as a connection to the compressor suction side and to the
hydraulic spaces. The solenoid valve block is connected
to the oil pump via a separate connection.
In addition to the solenoid valves, control valves are
attached to the blocks. The adjusting speed of control
slide and Vi-slide can be influenced by means of these
valves by controlling the flow rate (cf. chapter
Connections, Schematic Diagram, Valves).
AISH03-1_gbr.doc - 8/9
02.04.02/0
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
OVERFLOW VALVE
02.04.02/ 0
AISH03-1_gbr.doc - 9/9
Grasso
Refrigeration Division
CONNECTIONS
SCREW COMPRESSORS
SH SERIES, TYPES C, D, E, G
P + I diagram
Internal Piping Diagram
Connectio ns
Input Voltage for Pickups and Valves
Outer View of Compressor
11/2001/ Rev.2
AISH04-1_gbr.doc - 1/7
P+I DIAGRAM
The P+I diagram of the internal piping schematic of the screw compressor shown applies to standard application
in single-stage high-pressure operation. For other applications, e.g. in parallel operation, tandem application or,
when an external oil pump is used, there will be deviations from the piping schematic shown. For this purpose,
there exist separate simplified P+I diagrams listed in the data sheet 040800 with indication of special P+I
numbers. The data sheet is contained in the Product Information for Screw Compressors.
For the following piping schematic for standard application, the P+I diagram No. SM11 applies which is also
contained in data sheet 040800.
The nameplate of each compressor is marked with the pertaining P+I number.
701
AISH04-1_gbr.doc - 2/7
11/2001/ Rev.2
Pos.
Designation
Y1
Y2
Y3
Y4
242
346
Suction filter
452
243
Check valve
618
454
Oil pump
119
Oil filter
86
413
701
Overflow valve
24
25
27
28
29
105
Drain valve
105
Drain valve
106
Y5
Y6
11/2001/ Rev.2
AISH04-1_gbr.doc - 3/7
CONNECTIONS / THREADS
Item
A
B1/ B2
Purpose
Nominal width/threads
C/D
E/G
Suction nozzle
DN 80
DN 100
DN 50
DN 65
M 26 x 1,5
M 26 x 1,5
M 33 x 2
M 33 x 2
Oil supply
Economizer
E1
M 14 x 1,5
M 14 x 1,5
E2
M 14 x 1,5
M 14 x 1,5
M 14 x 1,5
M 14 x 1,5
M 16 x 1,5
M 16 x 1,5
G1
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
O1
O2
Additional connection
M 26 x 1,5
M 26 x 1,5
M 10 x 1,0
CONNECTIONS / THREADS
Item
Purpose
Nominal width/threads
C/D
E/G
X1
X2
27
M 12 x 1,5
M 12 x 1,5
28
M 12 x 1,5
M 12 x 1,5
29
M 12 x 1,5
M 12 x 1,5
106
AISH04-1_gbr.doc - 4/7
11/2001/ Rev.2
INPUT VOLTAGE
Item
Input
Output
24 V (DC)
4 - 20 mA
Y1/Y4
240 V AC
220 V AC
Y2/Y3
110 V AC
48 V AC
42 V AC
Y5
24 V DC
220 V AC,
Y6
expl.-proof
452
Purpose
11/2001/ Rev.2
AISH04-1_gbr.doc - 5/7
AISH04-1_gbr.doc - 6/7
11/2001/ Rev.2
11/2001/ Rev.2
AISH04-1_gbr.doc - 7/7
OVERALL CONCEPT
Grasso
Refrigeration Division
OVERALL CONCEPT
SCREW COMPRESSORS
MC SERIES, TYPES H, L, M, N
01.2003/2
Introduction
Compression
Capacity control
Vi-Adjustment
AI_MC_02_gbr.DOC - 1/5
Grasso
OVERALL CONCEPT
Refrigeration Division
INTRODUCTION
Screw compressors of oil-flooded construction with
continuously variable capacity control and an
adjustable Vi-volume ratio. The compressors are
compactly designed and have the following integrated
subassemblies:
Suction filter
Special compressor types without integrated subassemblies may be designed for special application
fields. See compressor parts list.
The two rotors have a distinctive spiral gearing with
asymmetrical profile. They operate with a very small
clearance and are completely encased.
The male rotor driven by the motor has 5 teeth and it
drives the female rotor with 6 teeth. Cylindrical roller
bearings with increased load-carrying capacity absorb
the radial forces and angular contact ball bearings
absorb the axial forces. A balancing piston arranged
on the male rotor shaft reduces the forces on the
angular contact ball bearings. An oil-sealed and
balanced mechanical contact seal ensures that the
driving shaft is sealed off.
The capacity of the compressor and its internal
volume ratio Vi can be adjusted by means of two
adjustable slides, the control slide and the Vi-slide.
The slides are adjusted hydraulically by the flanged or
external oil pump. Hermetically sealed display systems
which function inductively are used to indicate the
position of the slides.
The entire oil supply system is arranged inside the
casing. Oil connections for functional oil and cooling
oil are connected to the oil system of the screw
compressor unit only.
The functional oil fulfils the following purposes :
Vi-adjustment,
AI_MC_02_gbr.DOC - 2/5
01.2003/2
OVERALL CONCEPT
Grasso
Refrigeration Division
suction filter
suction nozzle
check valve
solenoid valve block
for Vi adjustment
Vi-slide
control slide
discharge nozzle
Figure 1: Schematic diagram of the screw compressor
01.2003/2
AI_MC_02_gbr.DOC - 3/5
OVERALL CONCEPT
Grasso
Refrigeration Division
COMPRESSION
While the rotors are turning, the meshing shifts from
the suction side to the discharge side. A V-shaped
space is formed between 2 male and female teeth in
each case which increases to a maximum size (Suction
process: Figure 2; 1-3, View of the upper side of the
rotors).
Suction side
Discharge side
AI_MC_02_gbr.DOC - 4/5
01.2003/2
OVERALL CONCEPT
Grasso
Refrigeration Division
CAPACITY CONTROL/VI-ADJUSTMENT
Capacity control is based on the control of the
volume. It functions according to the principle of
effectively shortening the stroke. This is achieved by
means of the control slide which is part of the casing
wall. When the control slide is adjusted, a bypass
opening emerges which provides a connection to the
suction area of the compressor (Figure 3).
Control edge
Vi-slide
Outlet opening
Control slide
Bypass opening
Bypass opening
01.2003/2
Control edge
Control slide
Vi-slide
Vi-slide
Control slide
Figure 3: Principle of capacity control and
Vi-adjustment
AI_MC_02_gbr.DOC - 5/5
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
DESCRIPTION OF DESIGN
SCREW COMPRESSORS
MC SERIES, TYPES H, L, M, N
01.2003/2
Casing
Check valve/ filter suction side
Rotors
Bearings
Shaft Sealing
Oil pump
Capacity control/ Vi-adjustment
Solenoid valve blocks
Display System of Slide Position
AI_MC_03_gbr.DOC - 1/4
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
CASING
The casing is made of grey cast iron and designed in
two parts. It consists of a rotor suction casing and a
pressure casing, and it has vertical parting joints.
The connecting flanges which connect the suction side
to the discharge side are arranged horizontally.
The casing parts and the covers and flanges located in
the casing are sealed with O-rings.
Screw-plugs are provided for oil drainage.
Covering flanges with guide surfaces for the Vi-slide
are attached to the front wall of the working area on
the suction side.
The axial outlet opening is integrated in the front wall
of the working area on the discharge side.
NON-RETURN VALVE/FILTER SUCTION SIDE
Non-return valve and suction filter are arranged on
the upper side of the rotor suction casing .The filter
insert has a filter mesh size of 100 m and the gas
flows from inside to outside.
BEARINGS
As a result of compression, radial and axial forces act
on the rotors. These forces are absorbed by
appropriate bearing elements.
The radial forces are absorbed by high-performance
cylindrical roller bearings with a solid cage. Bearings of
differing sizes are installed on the discharge side of
the male and female rotor. This takes into account the
different force levels whilst utilizing the available
space.
Angular contact ball bearings, which are installed
crosswise in pairs, absorb the axial forces. In addition,
they ensure precise axial guidance and positioning of
the rotors. The angular contact ball bearings are
equipped with a solid cage for the special requirements in the screw-compressor. They have radial
clearance at the outer rings towards the casing which
precludes a radial load and increases their service life.
The outer rings are firmly tightened axially to prevent
them from rotating.
Large axial forces act on the male rotor. A balancing
piston is therefore arranged on the male rotor shaft
end on the suction side of the compressor to unload
the axial bearing.
AI_MC_03_gbr.DOC - 2/4
SHAFT SEAL
The driven male rotor is sealed on the shaft bushing
on the suction end by means of an oil-sealed
mechanical contact seal. This seal has a balanced
design so as to achieve a maximum service life.
The counter ring arranged in the cover is made of
antimonous combined hard carbon and the elastic
slide ring which rotates with the shaft is made of a
high-quality grey cast iron alloy. An O-ring takes over
the secondary sealing between the slide ring and the
shaft. The sealing space which is under compression
discharge pressure is supplied with lubricating oil. This
space is sealed off towards the inside area of the
compressor by the balancing piston. The
sealingsurfaces of the carbon ring and counter ring
face one another without contact. They are separated
from one another by a thin oil film. Although there is a
slight amount of leakage, a high service life is however
attained.
01.2003/2
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
OIL PUMP
The oil of the oil pump is required to activate the
hydraulic device of the capacity control. The oil pump
is flanged at the frontage of the rotor casing.The
female rotor drives the oil pump. A partial flow from
the space of the shaft seal is conducted via internal oil
drainage holes to the suction side of the oil pump.
The oil from the discharge side of the oil pump enter
the solenoid valve block of the capacity control via
external pipe.
A overflow valve under the solenoid valve block
controls the pressure of the pump and conducts the
excess oil to the internal oil system of the compressor.
The pressure transmitter for measuring the pressure of
the oil pump is installed at the solenoid valve block.
The flanged oil pump at the compressor does not
exist, when the package has a external oil pump.
Stop sleeve
AI_MC_03_gbr.DOC - 3/4
Grasso
DESCRIPTION OF DESIGN
Refrigeration Division
Positioning of the Vi-slide towards the suction side (Vireduction or outlet window enlargement) takes places
by means of the prevailing pressure difference
between the discharge and suction pressure on the
front sides of the slide. Here oil under discharge
pressure enters the cylinder area thus balancing the
forces acting on the piston.
The cylinder area is filled and drained via internal
drainage holes and solenoid valves which are attached
to the closure flange of the compressor.
Compressors of the standard design which have a
fixed volume ratio Vi are not fitted with a Vi-slide. The
control slides are provided with an outlet opening
corresponding to a Vi of 2.6, 3.6, 4.8 or 5.5.
The Vi level must be determined before the
compressor is manufactured. This value depends on
the subsequent operating conditions (suction pressure,
discharge pressure).
SOLENOID VALVE BLOCKS
The hydraulic spaces of capacity control and Viadjusting device are connected to the oil system of
the oil pump or to the compressor suction space
alternately via the solenoid valve blocks.
P Oil pump
Po
MIN
MAX
AI_MC_03_gbr.DOC - 4/4
01.2003/2
Grasso
Refrigeration Division
01.2003/2
P + I Diagrams
Connections, Threads
Input Voltage
External Connections
AI_MC_04_gbr.DOC - 1/5
Grasso
Refrigeration Division
P+I DIAGRAMS
The hints given in the following concerning the internal oil circuit solely apply to the standard application of the
compressor in single-stage high-pressure operation. For the most different other cases of application of the
compressors (e. g. high-pressure operation, booster application, parallel- or tandem operation, flanged or
external oil pump), various versions and connection possibilities will be used. For a better understanding of this
great variety, there exist simplified P+I diagrams given on special data sheets in the Product Information on
Screw Compressors. The numbers of these
P+I diagrams are indicated on the type plate of the corresponding compressor.
CONNECTIONS / THREADS
Item
Purpose
Suction nozzle
Discharge nozzle
M/N
DN 125
DN 150
DN 80
DN 100
C1
Functional oil
M 22 x 1,5
M 22 x 1,5
C2
Functional oil
M 22 x 1,5
M 22 x 1,5
M 26x1,5
Economizer
M 42 x 2
M 48x2
G1
M 16 x 1,5
M 22 x 1,5
G2
M 16 x 1,5
M 22 x 1,5
M 16 x 1,5
M 22 x 1,5
M 12 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 16 x 1,5
M 12 x 1,5
M 12 x 1,5
M 12 x 1,5
M 12 x 1,5
DN 80
DN 80
M 16 x 1,5
M 16 x 1,5
W1
M 16 x 1,5
M 22 x 1,5
W2
M 12 x 1,5
M 12 x 1,5
W3
M 12 x 1,5
M 22 x 1,5
--
--
Vibration damper
Z1
Additional connection
M 16 x 1,5
M 16 x 1,5
Z2
Additional connection
M 16 x 1,5
M 16 x 1,5
AI_MC_04_gbr.DOC - 2/5
01.2003/2
Grasso
Refrigeration Division
INPUT VOLTAGE
Item
Purpose
Input
Output
U1
24 V (DC)
4 - 20 mA
U2
24 V (DC)
4 - 20 mA
Y1/Y4
240 V AC
220 V AC
Y2/Y3
110 V AC
48 V AC
Y5
42 V AC
24 V DC
Y6
01.2003/2
220 V AC,
expl.-proof
AI_MC_04_gbr.DOC - 3/5
Grasso
Refrigeration Division
EXTERNAL CONNECTIONS
AI_MC_04_gbr.DOC - 4/5
01.2003/2
Grasso
Refrigeration Division
C2
C1
Female rotor
Oil pump
Male rotor
Discharge
side bearing
C2
Function oil
Balance piston
Injection oil
(cooling oil)
C1
Shaft seal
Function oil
D
Check valve ( external)
Connections
pressure transducer
Pressure control
valve - oil pump
Solenoid valve block
for capacity control
to capacity control
01.2003/2
AI_MC_04_gbr.DOC - 5/5
OVERALL CONCEPT
Grasso
Refrigeration Division
OVERALL CONCEPT
SCREW COMPRESSORS
LT SERIES,
TYPES P, R, S, T, V, W, Y, Z, XA, XB, XC, XD, XE, XF
Introduction
Compression
Oil system
Capacity control
Vi-Adjustment
07/2003
AI_LT_02_gbr.doc - 1/5
OVERALL CONCEPT
Grasso
Refrigeration Division
INTRODUCTION
The screw compressors herein described are twin-shaft
rotary piston machines operating on the positive
displacement principle with oil injection operating
with different refrigerants.
Both rotors are machined to a helical lobe asymmetric
profile intermeshing with minimal clearance and
enclosed in a housing.
The male rotor having 5 or 4 lobes and driven by the
motor drives in its turn the female rotor having 6
lobes.
Journal bearings support radial loads, and angular ball
bearings axial loads. A compensating (balance)
unloading piston fittet to the male rotor shaft reduces
axial-loading on the ball bearings. The drive shaft is
fitted with an oil-retaining, unloaded shaft seal.
The compressor's capacity and internal volume ratio Vi
can be set by two adjustable slides, i.e. the primary
Inlet
Radial bearing
Male rotor
Axial bearing
Shaft seal
Outlet
Position
sensor
Hydraulically
system
Secondary
slide
Primary
slide
Balance
piston
AI_LT_02_gbr.doc - 2/5
07/2003
OVERALL CONCEPT
Grasso
Refrigeration Division
COMPRESSION
Suction side
Discharge side
07/2003
AI_LT_02_gbr.doc - 3/5
OVERALL CONCEPT
Grasso
Refrigeration Division
OIL SYSTEM
CAPACITY CONTROL
AI_LT_02_gbr.doc - 4/5
07/2003
OVERALL CONCEPT
Grasso
Refrigeration Division
Vi-ADJUSTMENT
The internal volume ratio Vi is an intrinsic characteristic of the screw compressor and is defined as the
ratio of the volume of interlobe space at the start to
that at the end of the compression process. Termination of compression and internal volume ratio Vi are
determined by the position of the radial discharge
port formed by the notches machined into the
primary-slide. Various Vi settings are obtained by
adjusting the primary slide in its full load position to
various axial displacements thus altering the size of
the radial discharge port. The internal volume ratio Vi
is adjusted to actual external operating conditions
(suction pressure, delivery pressure) so that the
pressure in the interlobe space at the discharge port
equals the required delivery pressure thus reducing
compression losses and power input to a minimum.
The full load setting of the primary-slide at its
optimum compression ratio is by means of the
compressor's memory programmed control device
operating according to an empirically derived
algorithm. The setting of the primary slide is
determined by an electronic position transmitter. Once
the primary slide is positioned the secondary slide is
brought up behind to butt against it. Both slides are
actuated hydraulically.
Optimum Vi
Rotor
Outlet
optimum
Vi position
Full load
position
Secondary slide control
Rotor
Outlet
Part load
position
optimum
Vi position
Internal By-pass
Rotor
Outlet
Part load
position
Part load
position
Internal By-pass
07/2003
AI_LT_02_gbr.doc - 5/5
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
DESCRIPTION OF DESIGN
SCREW COMPRESSORS
LT SERIES,
TYPES P, R, S, T, V, W, Y, Z, XA, XB, XC, XD, XE, XF
03/2004 /Rev.1
Casing
Rotors
Bearings
Shaft Seal
Capacity control
Vi-adjustment
Display of slide position
AI_LT_03_gbr.doc - 1/4
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
BEARINGS
Reference should be made to the lists of
parts and drawing index for a better
understanding of the following
descriptions.
CASING
The grey cast iron housing consists of three vertically
split sections namely the suction, rotor and discharge
casings. Suction intake is horizontal and discharge
outlet vertical. O-ring seals are fitted between the
individual casing-sections and are also fitted to the
housing cover and flanges.
SHAFT SEAL
AI_LT_03_gbr.doc - 2/4
03/2004/ Rev.1
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
CAPACITY CONTROL
Vi-DISPLACEMENT
Primary slide
Secondary slide
Figure 1 Capacity control / Vi-Adjusting Device
P0
P
MIN
MAX
P
P0
Primary slide
Secondary slide
03/2004 /Rev.1
AI_LT_03_gbr.doc - 3/4
DESCRIPTION OF DESIGN
Grasso
Refrigeration Division
2. Secondary slide
Types P, R, S, T, V, W, Y, Z, XA
The position of the primary slide (Vi variable) or
control slide (fixed Vi) is determined by the HDT
(Hermetic Differential Transformer) indicator-system
mounted on the cover plate of the capacity control
unit.
By means of 2 series connected tension springs of
different lengths the large length of adjustment of the
slide/piston rod/hydraulic piston complex can be
reduced to a small length which corresponds to the
measuring range of the position sensor.
A long pin is attached to the junction of both springs
where a small length of adjustment appears. The end
of the pin slides into a coil of the position sensor thus
generating a measuring signal by altering the
inductivity.
All types
Depending on the position of the slide, i.e. depth of
the pin immersion, the position sensor supplies an
output signal of between 4 and 20 mA (for screw
compressors with variable Vi).
Setting of the Vi value results in the compressorcontrol device simultaneously correcting the output
signal of the indicating system so that the primary
slide full load position is always registered at 100 % on
the indicating device.
The compressor control device computes the optimum
Vi value for setting the position of the primary slide.
AI_LT_03_gbr.doc - 4/4
03/2004/ Rev.1
CONNECTIONS
Grasso
Refrigeration Division
CONNECTIONS
SCREW COMPRESSORS
LT SERIES, TYPES P, R, S, T, V, W, Y
Connections, Threads
Input Voltage
External Connections Type P
External Connections Type R, S, T
External Connections Type V, Y
External Connections Type W
03.2004/4
AI_PY_04_gbr.doc - 1/7
CONNECTIONS
Grasso
Refrigeration Division
CONNECTIONS / THREADS
Item
Purpose
P
Nominal width/threads
R, S, T
V, W, Y
Suction nozzle
NB 150
NB 175
NB 250
Discharge nozzle
NB 100
NB 100
NB 150
M22x1,5
M22x1,5
M22x1,5
Oil injection
compression chamber
M22x1,5
M22x1,5
V: M22x1,5
W:M26x1,5
Y: M22x1,5
M22x1,5
M22x1,5
M22x1,5
M22x1,5
M22x1,5
M22x1,5
D1
M22x1,5
M22x1,5
M22x1,5
M22x1,5
M22x1,5
M22x1,5
Oil return
capacity control
M22x1,5
M22x1,5
V: M22x1,5
W: Y: M22x1,5
H1
M22x1,5
M22x1,5
M22x1,5
H2
M22x1,5
M22x1,5
Oil supply,
direction part load
V: M16x1,5
W: Y: M16x1,5
Oil supply,
direction full load
V: M22x1,5
W: Y: M22x1,5
V: M16x1,5
W: Y: M16x1,5
M16x1,5
M16x1,5
M16x1,5
M26x1,5
M26x1,5
M33x2
Economizer port
NB 40/ M48x2
NB 40/ M48x2
NB 65
O1
M14x1,5
M22x1,5
V: M16x1,5
W:M12x1,5
Y: M16x1,5
O2
M22x1,5
M22x1,5
M22x1,5
O3
M16x1,5
M16x1,5
AI_PY_04_gbr.doc - 2/7
03.2004/4
CONNECTIONS
Grasso
Refrigeration Division
INPUT VOLTAGE
Item
Y1/Y4
Y2/Y3
Purpose
Solenoid valves capacity control,
direction full load
Solenoid valves capacity control,
direction part load
Y5
Solenoid valve
variable Vi
Y6
Solenoid valve
variable Vi
Z1
03.2004/4
P, R, S, T, W
240 V AC
220 V AC
110 V AC
48 V AC
42 V AC
24 V DC
220 V AC
expl.-proof
Inlet: 24 V (DC)
Output: 4-20 mA
AI_PY_04_gbr.doc - 3/7
CONNECTIONS
Grasso
Refrigeration Division
AI_PY_04_gbr.doc - 4/7
03.2004/4
CONNECTIONS
Grasso
Refrigeration Division
03.2004/4
AI_PY_04_gbr.doc - 5/7
CONNECTIONS
Grasso
Refrigeration Division
AI_PY_04_gbr.doc - 6/7
03.2004/4
CONNECTIONS
Grasso
Refrigeration Division
03.2004/4
AI_PY_04_gbr.doc - 7/7
CONNECTIONS
Grasso
Refrigeration Division
CONNECTIONS
SCREW COMPRESSORS
LT SERIES,
TYPES Z, XA, XB, XC, XD, XE, XF
03/2004 rev.1
Connections, Threads
Input Voltage
AI_Z_XF_04_gbr.doc - 1/6
CONNECTIONS
Grasso
Refrigeration Division
CONNECTIONS / THREADS
Item
Purpose
Z, XA
Nominal width/threads
XB, XC, XD
XE , XF
Suction nozzle
NB 250
NB 300
NB 400
Pipe O.D. 412 mm
Discharge nozzle
NB 150
NB 200
NB 250
Pipe O.D. 273 mm
M22x1,5
M22 x 1,5
M26 x 1,5
Oil injection
compression chamber
Z: M26x1,5
XA: M33x2
NB 50
Pipe O.D. 63
NB 80
Pipe O.D. 80 mm
B1
NB 50
Pipe O.D. 63
NB 80
Pipe O.D. 80 mm
M22x1,5
M22 x 1,5
M26 x 1,5
M22x1,5
M22 x 1,5
M26 x 1,5
D1
M22x1,5
M22 x 1,5
M26 x 1,5
G 1/4
G 1/4
G 1/4
M22x1,5
M22 x 1,5
M26 x 1,5
M33 x 2
M26 x 1,5
NB 25
Pipe O.D. 27 mm
M26 x 1,5
NB 25
Pipe O.D. 27 mm
F1
H1
H2
M22x1,5
M16x1,5
M22 x 1,5
M22 x 1,5
M33x2
M42 x 2
NB 80
Pipe O.D. 80 mm
NB 100
NB 125
Pipe 140 mm
NB 150
Pipe O.D. 168 mm
R1
NB 125
Pipe 140 mm
NB 150
Pipe O.D. 168 mm
O1
M12x1,5
M22 X 1,5
M22 x 1,5
O2
M22 X 1,5
M22 x 1,5
AI_Z_XF_04_gbr.doc - 2/6
M22x1,5
03/2004 rev.1
CONNECTIONS
Grasso
Refrigeration Division
INPUT VOLTAGE
Item
Y1/Y4
Y2/Y3
Purpose
Solenoid valves capacity control,
direction full load
Solenoid valves capacity control,
direction part load
Y5
Solenoid valve
variable Vi
Y6
Solenoid valve
variable Vi
Z1
03/2004 rev.1
Inlet: 24 V (DC)
Output: 4-20 mA
AI_Z_XF_04_gbr.doc - 3/6
CONNECTIONS
Grasso
Refrigeration Division
AI_Z_XF_04_gbr.doc - 4/6
03/2004 rev.1
CONNECTIONS
Grasso
Refrigeration Division
03/2004 rev.1
AI_Z_XF_04_gbr.doc - 5/6
CONNECTIONS
Grasso
Refrigeration Division
AI_Z_XF_04_gbr.doc - 6/6
03/2004 rev.1
02/04
Master_Backpage.doc