TWIN SCREW COMPRESSORS - High quality industrial

Transcription

TWIN SCREW COMPRESSORS
Today in thousands of application worldwide, Howden oil injected screw compressors are regularly applied to
provide high integrity, low maintenance solutions for liquid chilling, direct refrigeration and gas compression
applications.
Howden not only introduced the concept of the operational twin screw compressor to the world market more
than 50 years ago, but have been instrumental in the development of the oil injected twin screw compressor
concept, which has revolutionised world designs of refrigeration and gas handling plants.
COMPRESSION
CYCLE
(Diagrammatic only)
The international installed base of Howden Compressors in a wide and varied range of applications is
unparalleled.
DESIGN CONCEPT
Compression is achieved by the intermeshing of two helical rotors contained in a suitable casing. Figures 1-4
give details of the compression cycle.
Fig 1
Gas is drawn in to fill
the interlobe space
between adjacent
lobes.
The Howden twin screw compressor is a positive displacement rotary design. As such, Howden compressors
have the characteristics and stability of reciprocating compressors by offer particular advantages of :
Reduced Physical Size
Low Vibration
Reduced Moving Parts
Extended Operating Life Cycle
CONSTRUCTION
All Howden twin screw compressors have paired rotors, machined from solid bar or forgings which involves a
high degree of complexity and accuracy.
Fig 2
As the rotors mesh, the
gas is trapped between
the rotors and the
casing.
Normally casings will be cast iron, machined to close tolerance levels. However, to match particular gas
requirements, high discharge pressure applications, or applicable international standards and codes, alternative
casing construction in spheroidal graphite iron or various grades of steel will be offered when appropriate.
Alternative designs of compressors from the Howden product range are available as required. Some typical
examples of alternatives are given below :
Twin Wall Construction with Sleeve Bearings
Single Wall Construction with Roller Bearings
Slide Valve Capacity Control from 100-10 percent
Inverter Speed Control
Variable Volume Ratio
Fig 3
Continued rotation
progressively reduces
sthe soace occuoied by
the gas, causing
compression
Fig 4
Compression continues
until the interlobe
space becomes exposed
to the outlet port,
through which the gas
is discharged
Superfeed
Oil cooling
Liquid Refrigeration Injection
Specialist Sealing Systems
FEATURES AND BENEFITS
Positive Displacement
Cannot surge. High compression ratios per stage.
Rotary Action
Vibration free running.
Extreme reliability & on-line availability.
Smooth gas flow, low pulsation.
Lightweight foundations.
Stiff Action Rotors
Ability to withstand high pressure differences.
No Inlet or Outlet Valves
Lower maintenance costs
Compact Size & Light Weight
Minimal space and foundation requirement, resulting
in low installation costs.
Designed for Long Periods of
Maximum on-line availability
Minimal service requirements
Continuous Running
2
DEVELOPMENT AND TESTING
DESIGN
Howden twin screw compressors are designed to match the exacting
specifications required by our customers and comply with
International Standards and Codes.
Howden ensure that their compressors go beyond the normal operating
technical performance parameters required to give customers wide
margins in terms of operational capability and efficiency.
Compressors are generally Lloyds approved and installations have
been accepted by many major authorities, such as Lloyds, Bureau
Veritas, Norske Veritas, RINA, DSRK, Bureau de Mines,
Germanischer Lloyd and NKK.
DEVELOPMENT
TEST
Howden’s technology lead has been maintained over many
years by total commitment to continuous product development.
At Howden Compressors, test is considered to be a vital function, both
in terms of product development and to ensure specification
compliance.
Market requirements are continuously reviewed, in order that
the Development Department can not only monitor ever
changing operating conditions, but ensure that production
capability will always reflect current or anticipated
system demands worldwide.
In particular, Howden is totally committed to ensure that
products meet current or future demands for environmental
protection, in terms of CFC free refrigerants, secure captivity
of hazardous gases, and the best possible energy efficiency.
All new products are comprehensively tested, to ensure that design is
fully optimised and performance data provided by the company,
particularly in the form of computer selection programs for standard
gases and refrigerants, is as accurate as possible.
In addition, all compressors are hydrostatically tested to a minimum of
1.5 times maximum working pressure, and are also subjected to
mechanical run function test on one of Howden’s air test rigs, to
ensure that volumetric efficiency, mechanical function, and vibration
fall within stringent acceptance standards.
All Howden Compressors’ products are capable of operation
on CFC free refrigerants, with the fullest possible attention
being given to energy conservation. In the development of
our new XRV range of compressors, for example, both full
capacity and volume ratio control are available.
QUALITY CONTROL
Howden Compressors recognise the importance of a controlled
manufacturing environment, where design, development,
procurement, production and test are controlled in such a way
as to ensure the highest possible standards of production and
performance, demanded by Howden and their customers, are
consistently achieved.
To this end, the company operates to the requirements of ISO 9001
(BS5750-Part 1, EN 29001) and has been accredited by Lloyds Register
Quality Assurance as complying with this standard.
Ongoing internal and external audits of quality control systems are
applied to ensure continued compliance with necessary control
procedures.
Quality Plans can also be prepared to match project requirements,
where we are required to manufacture to specific customer
requirements, which may apply in particular applications.
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MANUFACTURING & CUSTOMER SUPPORT
ROTORS
All Howden twin screw rotors are machined from solid bar or
forgings. Standard material is carbon steel, but for more arduous
applications, special alloys or stainless steels are utilised.
Rotors are machined on specialist machining centres, to the exacting
tolerances necessary to ensure the highest possible operating
efficiency.
•
CNC rotor machining
centre in operation.
A feature of Howden rotors is that sealing strips are machined on the
crown of the male rotor lobes, and matching grooves are incorporated
in the root of the female rotor to maximise the gas seal.
•
Completion of the
manufacturing process in
the rotor machining
centre.
•
Finished machined
compressor casing.
•
Final inspection of a WRV
510 compressor prior to
shipment.
•
Original Howden
Spares Kits
Following machining and balancing to ISO standards, male and
female rotors are paired for assembly to ensure the ideal combination
for maximum efficiency.
CASINGS
Casings are precision machined from castings, which will normally
be graphite cast iron, but may be nodular iron, carbon steels, or
stainless steel, depending on the application.
As with the twin screw rotors, precision machining of compression
path components is critical, to ensure that Howden standards are
maintained in terms of operational efficiency.
•
Precision machining of
a WRV compressor
casing.
Components such as the main casing and inlet and outlet end covers
are flanged, bolted and dowelled through flanges to ensure correct
alignment. Removal of the end covers provides ready access for
maintenance when required.
COMPRESSOR ASSEMBLY
All oil injected twin screw compressors are assembled in the
Glasgow production facility by skilled engineers, who ensure that
Howden quality control requirements, which conform with ISO 9001,
are strictly maintained.
•
Assembly of a large
WRV compressor.
During the manufacturing process, all casing components are
subjected to hydraulic test, to a minimum of 1.5 times maximum
operating pressure, to ensure integrity.
Additionally, all oil injected compressors are tested with air under
water following final assembly. Compressors are then mechanically
run, to confirm that volumetric efficiency, absorbed power, oil flows
and vibration are to Howden acceptance standards.
PRODUCT SUPPORT – SPARE PARTS AND RE-BUILD
CAPACITY
In partnership with its global alliance of gas and refrigeration
package manufacturers and distributors, Howden offers a fast and
efficient parts supply service.
•
Assembly of WRV oil
injected compressors.
Parts are generally pre-packaged in kits which, in addition to being
readily available from Howden facilities in the UK and the USA, will
normally be available from locally based Howden compressor package
distributors.
Following many years’ operation, a full service re-build of the
compressor may be appropriate. A full re-build and re-test capability
is offered by Howden in both their UK and USA service shops.
A full warranty, equivalent to new product warranty, is available to
Howden customers following a full compressor re-build.
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OIL INJECTED COMPRESSORS
Howden oil injected twin screw compressors are used for liquid
chilling, direct refrigeration, and for hydrocarbon gas applications
involving hydrocarbons, fuel gas, or other specialist applications.
In some instances, hydrocarbon gases such as propane, butane or
propylene, will be used as an industrial refrigerant.
TYPICAL APPLICATIONS

Industrial Refrigeration
Fuel Gas Compression
Liquid Chillers
Food Processing
Marine Air Conditioning &
Refrigeration
Breweries
Mine Cooling
SUPERFEED
The Howden Superfeed system is a development of the oil
injected screw compressor design.
All oil injected
compressors are equipped with an additional gas port, located
along the length of the compression chamber.
Feeding refrigerant to this port from a superfeed/economiser
vessel within the refrigeration system offers increased
evaporator capacity of up to 20 percent, with virtually no
increase in absorbed power.
UNIQUE FEATURES AND BENEFITS OF OIL INJECTED
DESIGN
Slide Valve Capacity Control
Capacity and energy absorbed
match system demand.
Variable Volume Ratio
Maximises energy efficiency.
Liquid Refrigerant Injection
Reduces capital cost with
minimal reduction in operating
efficiency.
GAS HANDLING
Typical gases or refrigerants handled by the Howden range of oil
injected screw compressors include:
Refrigerants
Gases

NH3
R12/R134a
R22/KLEA 66/AZ5000
R502/R404A/R407A/
AZ 50
Propane
Butane
Propylene
OIL INJECTED COMPRESSOR RANGE
Howden offer a range of capability which is unparalleled
Hydrocarbon Processing
Gas Liquefaction
Petrochemical and
Chemical Processing
Natural Gas Gathering
Carbon Dioxide Recovery
Coke Oven Gas

Ammonia
Butane
Coke Oven Gas
Fuel Gas
Helium
Hydrocarbon
(Wet & Mixed)
Hydrogen
Methane
Natural Gas
Nitrogen
Propane
Propylene
Sour Gas
Town Gas
N.B: In some cases, for example in refineries, hydrocarbon gases will
be used as refrigerants.
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WRV COMPRESSORS
WRV compressors represent the “bench mark” against which industry
comparison is made for both gas and refrigeration applications.
Features and benefits of WRV compressors include:
Plain-Shell Type Journal
Bearings
Long operational life span
Double Wall Construction
Suitable for high pressure
application
Optional Material of
Construction
Flexibility to match project
specification
(e.g. API 619)
Oil Injected Seal/
Bearing Construction
High quality gas seal
from simple construction
Range of Capability
Probably the most comprehensive
range of capacity available
Installed Compressors
More than 20,000 WRV
compressors installed
worldwide
All WRV range compressors are of double wall construction and
utilise white metal, sleeve type journal bearings with pressurised
shaft seal.
A full range of Vi options from 2.1 to 5.8 is offered for each
compressor while slide valve capacity control is a standard feature
on all compressors.
Many options to standard design are available, some of which are
indicated below :
C
“Conditioning” version with reduced oil flow for dense gases
such as R22
M “Mirror” version for reverse rotation with double ended motor
drive and two stage design.
H “Higher pressure” version for high discharge pressure.
X “eXtra high” discharge design.
T “Tilting pad” thrust bearing design, e.g. to comply with API 619.
S “Steel casings ” for high pressure or to match specification.
N “Nodular cast iron design” again for specific project specification.
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XRV COMPRESSORS
XRV compressors have been developed specially for the
refrigeration market.
Features and benefits of XRV compressors include :
Ease of Installation
Ideal for horizontal
separator applications
Use of Roller Bearings
No oil pump for over
90% of installations
Variable Vi
Available with either adjustable or fully
automatic Vi system
Stepless Capacity Control Combined with variable Vi, gives
maximum energy saving
Ease of Service
Separate end covers give easy
access to rolling elements
VARIABLE VOLUME RATIO
Two forms of variable volume control are available.
1.
ADJUSTABLE VOLUME RATIO (MVi)
2.
AUTOMATIC VARIABLE VOLUME RATIO (AVi)
As is known, care is taken during compressor selection to ensure that the correct
volume ratio is selected by comparison to the chosen operating conditions.
However, in many instances the compressor is selected against peak conditions
which may only apply for a very few days each year.
While it is essential to select hardware which is capable of operating in the most
extreme environment, it does not follow that the compressor will necessarily
always perform at the highest possible efficiency.
The Howden variable Vi concept, coupled to slide valve capacity control, offers
alternative methods of controlling capacity and volume ratio to suit site
conditions.
Where the pressure ratio across the compressor is consistently high or changes
in pressure ratio are infrequent (e.g. the change from winter to summer conditions)
then the MVi manually adjustable system will be entirely satisfactory.
With lower pressure ratios, or where condensing conditions vary frequently,
the Howden automatic control AVi system is ideal.
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WRV TECHNICAL DATA
TYPICAL PERFORMANCE
EVAPORATION TEMPERATURE
TYPICAL EFFECT OF SUPERFEED
KEY TO GRAPHS
Full Duty 50 Hz (Excluding Superfeed )
Condensing Temperature 95°F (35°C)
Full Duty 60 Hz (Excluding Superfeed)
AMMONIA
TYPICAL PERFORMANCE
R22
TYPICAL EFFECT OF SUPERFEED
NOTES
Refrigeration capacity based on 5.6°C (10°F) superheat
at compressor suction and no sub-cooling of condensed
liquid
No allowance has been made for pressure losses between
the evaporator and the compressor suction flange
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WRV TECHNICAL DATA
*SWEPT
HOWDEN
COMPRESSOR VOLUME
50Hz
SPECIFICATION
m3/hr
WRV 163/1.45
WRV 163/1.80
WRV 204/1.10
WRV 204/1.45
WRV 204/1.65
WRV 204/1.93
WRV 255/1.10
WRV 255/1.30
WRV 255/1.45
WRV 255/1.65
WRV 255/1.93
WRV 255/2.20
WRV 321/1.32
WRV 321/1.65
WRV 321/1.93
WRV 321/2.20
WRV 510/1.32
WRV 510/1.65
WRV 510/1.93
550
680
815
1095
1220
1340
1590
1755
2150
2395
2630
3190
3830
4790
5260
6385
7660
9575
10510
**SWEPT
VOLUME
60Hz
SUCTION
DISCHARGE
DIMENSION
DIMENSION
DIMENSION
DIMENSION
WEIGHT
PORT
PORT
A
B
C
D
APPROX
Ø
Ø
cfm
m3/hr
cfm
mm
in mm
325
400
480
645
720
790
935
1035
1270
1410
1550
1880
2255
2820
3095
3760
4510
5640
6190
660
820
975
1315
1465
1610
1905
2105
2580
2870
3155
3830
4595
5745
6310
7660
9190
11490
12615
390
480
575
775
860
950
1120
1240
1520
1690
1855
2255
2705
3380
3715
4510
5410
6760
7425
125
125
150
200
200
200
200
200
255
255
255
255
255
300
300
350
350
400
400
5
5
6
8
8
8
8
8
10
10
10
10
10
12
12
14
14
16
16
75
75
100
125
125
125
150
150
200
200
200
200
200
255
255
300
255
300
300
in
3
3
4
5
5
5
6
6
8
8
8
8
8
10
10
12
10
12
12
mm ft in
mm ft
in
mm ft in
mm
ft in
Kg
1063 3
1120 3
1201 3
1273 4
1314 4
1370 4
1391 4
1448 4
1487 4
1537 5
1604 5
1815 5
1914 6
2020 6
2110 6
2345 7
2920 9
3090 10
3233 10
490
490
640
640
640
640
692
692
692
692
692
692
940
940
940
940
1560
1560
1560
7¼
7¼
1⅛
1⅛
1⅛
1⅛
3¼
3¼
3¼
3¼
3¼
3¼
1
1
1
1
1⅜
1⅜
1⅜
248
248
310
310
310
310
349
349
349
349
349
349
471
471
471
471
750
750
750
250
250
315
315
315
315
362
362
362
362
362
362
500
500
500
500
750
750
750
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
2
2
2
470
495
760
850
887
925
1200
1270
1325
1422
1540
1650
2925
3150
3260
3500
10800
11500
11800
5⅞
8¼
11¼
2⅛
3¾
6
6¾
9
10½
0½
3⅛
11½
3⅜
7½
11
8⅜
7
1⅝
7¼
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
5
5
5
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
2
2
2
9¾
9¾
12¼
12¼
12¼
12¼
1¾
1¾
1¾
1¾
1¾
1¾
6½
6½
6½
6½
5½
5½
5½
9⅞
9⅞
12⅜
12⅜
12⅜
12⅜
2¼
2¼
2¼
2¼
2¼
2¼
7⅝
7⅝
7⅝
7⅝
5½
5½
5½
lb
1036
1091
1675
1874
1955
2039
2645
2799
2921
3134
3395
3638
6447
6943
7186
7715
23806
25349
26010
The company operates a policy of continuous product development and reserves the right to alter the data provided without notice
*Swept volume at 3,000 rpm except WRV510 range which is measured at 1,500rpm **Swept volume at 3,600 rpm exceptWRV510 which is measured at 1,800 rpm
TYPICAL GASES & REFRIGERANTS HANDLED BY HOWDEN OIL INJECTED COMPRESSORS
GASES
REFRIGERANTS
AMMONIA BUTANE
METHANE
PROPYLENE SOUR GAS
NATURAL NITROGEN COKE OVEN GAS HYDROGEN TOWN GAS
FUEL GAS PROPANE HELIUM
HYDROCARBON
NH3
R22/KLEA66/AZ5000 PROPANE
R12/R134a R502/R404A/R407A BUTANE
CAPABLE OF USING ALL NEW REFRIGERANTS
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XRV TECHNICAL DATA
TYPICAL PERFORMANCE
AMMONIA
Full Duty 50 Hz (Excluding Superfeed )
Full Duty 60Hz (Excluding Superfeed )
R22
EVAPORATING TEMPERATURE
KEY TO GRAPHS
TYPICAL PERFORMANCE
EVAPORATING TEMPERATURE
NOTES
Refrigeration capacity based on 5.6°C (10°F) superheat
at compressor suction and no sub-cooling of condensed
liquid
No allowance has been made for pressure losses between
the evaporator and the compressor suction flange
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XRV TECHNICAL DATA
XRV 127/1.65 Compressor ( with Anti-Clockwise Rotation)
HOWDEN
COMPRESSOR
SPECIFICATION
XRV 127-R1*
XRV 127-R3
XRV 127-R4
XRV 127-R5
SWEPT
VOLUME
50Hz
SWEPT
VOLUME
60Hz
m3/hr cfm m3/hr cfm
293 172 352 207
397 234
489 288
576 340
SUCTION
DISCHARGE
DIMENSION
PORT
Ø
mm
in
100
4
PORT
Ø
A
476 280
586 345
-
100
100
100
4
4
4
SWEPT
VOLUME
SWEPT
VOLUME
SUCTION
50Hz
60Hz
mm
50
50
50
50
DIMENSION DIMENSION DIMENSION
APPROX
B
C
D
mm ft in
201 0
75/ 16
291 0 11½
291 0 11½
291 0 11½
in
2
mm ft in
850 2 97/ 16
mm ft in
390 1 3⅜
mm ft in
299 0 11¾
2
2
2
900 2 117/ 16
900 2 117/ 16
900 2 117/ 16
390 1 3⅜
390 1 3⅜
390 1 3⅜
209 0 8¼
209 0 8¼
209 0 8¼
WEIGHT
Kg
250
lb
550
250
250
250
550
550
550
*With clockwise rotation
HOWDEN
COMPRESSORS
SPECIFICATION
XRV 163/1.65
XRV 163/1.93
XRV 204/1.10
XRV 204/1.45
XRV 204/1.65
XRV 204/1.93
DISCHARGE
DIMENSION DIMENSION DIMENSION DIMENSION
m3/hr
593
710
812
1070
1219
1348
cfm m3/hr
350
712
418
852
478
974
630 1284
717 1463
793 1618
cfm
420
500
573
756
860
952
D
C
B
A
PORT
PORT
Ø
Ø
mm
in mm
125
5
76
125
5
76
150
6
100
150
6
100
150
6
100
150
6
100
WEIGHT
APPROX
in
3
3
4
4
4
4
mm
1070
1116
1178
1249
1255
1312
ft
3
3
3
4
4
4
in
6⅛
8
10⅜
1⅛
1½
3⅝
mm
430
430
516
516
516
516
ft
1
1
1
1
1
1
in
5
5
8⅜
8⅜
8⅜
8⅜
mm
200
200
240
240
240
240
ft
0
0
0
0
0
0
in
7⅞
7⅞
9½
9½
9½
9½
mm
250
250
305
305
305
305
ft
0
0
0
0
0
0
in
9⅞
9⅞
12
12
12
12
Kg
364
388
636
660
690
736
lb
802
855
1400
1454
1520
1621
The company operates a policy of continuous product development and reserves the right to alter the data provided without notice
11
HEAD OFFICE & PLANT
Howden Compressors Limited
133 Barfillan Drive
Glasgow, G52 1BE
Scotland, UK
Tel: +44 (0) 141 882 3346
Fax: +44 (0) 141 882 8648
e-mail: sales@howdencompressors.co.uk
Website: www.howdencompressors.co.uk
SALES OFFICES
Howden Compressors Limited
Unit 2
Maple Grove Business Park
Off Lawrence Road
Green Lane
Hownslow West
Middlesex TW4 6JF
e-mail: how_comp_lon@compuserve.com
Howden Compressors LLC
1850B North Gravers Road
Plymouth Meeting, PA 19462
USA
Tel: (610) 313 9800
Fax: (610) 313 9215
e-mail: sales@howdencompressors.com
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