BUSCH COBRA User manual

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Instruction Manual
COBRA
Dry Screw Vacuum Pumps
NC 0100 B, NC 0200 B, NC 0300 B
(water-cooled version)
0870573306/-0004_en / Original instructions / Modifications reserved 14/09/2021

Table of Contents
2 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
Table of Contents
1 Safety ......................................................................................................................................4
2 Product Description...............................................................................................................5
2.1 Operating Principle.......................................................................................................... 6
2.2 Application....................................................................................................................... 6
2.3 Start Controls .................................................................................................................. 7
2.4 Water Cooling Variants ................................................................................................... 7
2.4.1 Direct Cooling....................................................................................................... 7
2.4.2 Plate Heat Exchanger (Optional).......................................................................... 7
2.5 Standard Features .......................................................................................................... 7
2.5.1 Temperature Switch ............................................................................................. 7
2.5.2 Thermometer ........................................................................................................ 7
2.5.3 Sealing Systems................................................................................................... 8
2.6 Optional Accessories ...................................................................................................... 8
2.6.1 Gas Ballast Valve ................................................................................................. 8
2.6.2 Silencer ................................................................................................................ 8
2.6.3 Barrier Gas System .............................................................................................. 8
2.6.4 Mechanical Seals .................................................................................................8
2.6.5 PTFE Shaft Seals................................................................................................. 8
2.6.6 Nitrogen Panel...................................................................................................... 8
2.6.7 Pressure Switch (Barrier Gas).............................................................................. 9
3 Transport ................................................................................................................................9
4 Storage....................................................................................................................................11
5 Installation ..............................................................................................................................11
5.1 Installation Conditions ..................................................................................................... 11
5.2 Connecting Lines / Pipes ................................................................................................ 13
5.2.1 Suction Connection ..............................................................................................13
5.2.2 Discharge Connection .......................................................................................... 13
5.2.3 Cooling Water Connection ................................................................................... 14
5.2.4 Barrier Gas System Connection (Optional) .......................................................... 15
5.2.5 Dilution Gas System Connection (Optional)......................................................... 16
5.2.6 Purge Gas System Connection (Optional) ........................................................... 17
5.3 Filling Oil ......................................................................................................................... 18
5.4 Filling Cooling Liquid ....................................................................................................... 20
5.5 Liquid Flushing Device Installation (Optional) ................................................................. 20
5.6 Fitting the Coupling ......................................................................................................... 21
5.7 Electrical Connection ...................................................................................................... 22
5.7.1 Wiring Diagram Three-Phase Motor (Pump Drive) .............................................. 23
5.7.2 Wiring Diagram Solenoid Valve (Optional)........................................................... 24
5.8 Electrical Connection of the Monitoring Devices............................................................. 24
5.8.1 Wiring Diagram Temperature Switch ................................................................... 24
5.8.2 Wiring Diagram Flow Switch (Optional)................................................................ 24
5.8.3 Wiring Diagram Pressure Switch (Optional)......................................................... 25
5.8.4 Wiring Diagram Level Switch (Optional)............................................................... 25
6 Commissioning ......................................................................................................................25
6.1 Conveying Condensable Vapours................................................................................... 26
6.2 Liquid Flushing Procedure .............................................................................................. 27
6.3 Gas Purging Procedure................................................................................................... 27
7 Maintenance ...........................................................................................................................28
7.1 Maintenance Schedule.................................................................................................... 29
7.2 Oil Level Inspection......................................................................................................... 29

Table of Contents
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 3
7.3 Cooling Liquid Level Inspection ...................................................................................... 30
7.4 Oil Change ...................................................................................................................... 31
7.5 Cooling Liquid Change.................................................................................................... 34
8 Overhaul..................................................................................................................................35
9 Decommissioning ..................................................................................................................35
9.1 Dismantling and Disposal................................................................................................ 35
10 Spare Parts .............................................................................................................................36
11 Troubleshooting.....................................................................................................................37
12 Technical Data........................................................................................................................39
13 Cooling Liquid........................................................................................................................39
14 Oil ............................................................................................................................................39
15 EU Declaration of Conformity...............................................................................................40

1 | Safety
4 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
1 Safety
Prior to handling the machine, this instruction manual should be read and understood.
If anything needs to be clarified, please contact your Busch representative.
Read this manual carefully before use and keep for future reference.
This instruction manual remains valid as long as the customer does not change any-
thing on the product.
The machine is intended for industrial use. It must be handled only by technically
trained personnel.
Always wear appropriate personal protective equipment in accordance with the local
regulations.
The machine has been designed and manufactured according to state-of-the-art meth-
ods. Nevertheless, residual risks may remain. This instruction manual highlights po-
tential hazards where appropriate. Safety notes and warning messages are tagged
with one of the keywords DANGER, WARNING, CAUTION, NOTICE and NOTE as
follows:
DANGER
... indicates an imminent dangerous situation that will result in death or serious injuries
if not prevented.
WARNING
... indicates a potentially dangerous situation that could result in death or serious inju-
ries.
CAUTION
... indicates a potentially dangerous situation that could result in minor injuries.
NOTICE
... indicates a potentially dangerous situation that could result in damage to property.
NOTE
... indicates helpful tips and recommendations, as well as information for efficient and
trouble-free operation.

Product Description | 2
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 5 / 44
2 Product Description
TM IN
OUT
TV
OSG
CWP
NP OFP
ODP, MP
OSG
PMR
CWO
CWDEB
OFP
GB TS
OUTCDSI
MTBODP, MP
CWI
CWD
CLDCWI CWO
CLFEV CLP
CLD
PHE
NC 0200 B with direct cooling
NC 0200 B with
direct cooling
NC 0200 B with silencer
NC 0100 B with
plate heat exchanger
SV
CD Condensate drain CLD Cooling liquid drain plug
CLF Cooling liquid fill plug CLP Cooling liquid pump
CWD Cooling water drain plug CWI Cooling water inlet
CWO Cooling water outlet CWP Cooling water pump
EB Eye bolt EV Expansion vessel
GB Gas ballast valve IN Suction connection
MP Magnetic plug MTB Motor terminal box
NP Nameplate ODP Oil drain plug
OFP Oil fill plug OSG Oil sight glass
OUT Discharge connection PHE Plate heat exchanger
PMR Plug for manual rotation of rotors SI Silencer
SV Safety valve TM Thermometer
TS Temperature switch TV Thermostatic valve

2 | Product Description
6 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
NOTE
Technical term.
In this instruction manual, we consider that the term ‘machine’ refers to the ‘vacuum
pump’.
NOTE
Illustrations
In this instruction manual the illustrations may differ from the machine appearance.
2.1 Operating Principle
Water-cooled version with direct cooling:
Water-cooled version with plate heat exchanger (optional):
The machine works on the one-stage, twin-screw pump principle.
Two screw rotors are rotating inside the cylinder. The pumped medium is trapped be-
tween the cylinder and screw chambers, compressed, and transported to the gas out-
let. During the compression process, the two screw rotors do not come into contact
with each other nor with the cylinder. There is no need for a lubrication or an operating
fluid in the compression chamber.
2.2 Application
The machine is intended for the suction of air and other dry, non-aggressive, non-toxic
and non-explosive gases.
Conveying of other media leads to an increased thermal and/or mechanical load on
the machine and is permissible only after a consultation with Busch.
The machine is intended for the placement in a non-potentially explosive environment.
The machine is capable of maintaining ultimate pressure, see Technical Data [►39].
The machine is suitable for continuous operation.

Product Description | 2
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 7 / 44
Permitted environmental conditions, see Technical Data [►39].
2.3 Start Controls
The machine comes without start controls. The control of the machine is to be provid-
ed in the course of installation.
The machine can be optionally equipped with a starter unit or a variable-frequency
drive.
2.4 Water Cooling Variants
2.4.1 Direct Cooling
The machine is cooled by a cooling water circuit in the cylinder cover and cylinder.
The cooling water pump (CWP) allows a recirculating flow in the cooling water cham-
ber.
The thermostatic valve (TV) allows a temperature regulation of the machine by regu-
lating the cooling water flow.
The adjustment of thermostatic valve from position 1 (cool position) to the position 5
(hot position) alters the cooling water temperature and must correspond to the applica-
tion requirements.
NOTE
Busch recommendations for the thermostatic valve adjustment:
• The position 1 (cold position) is mainly intended for applications with a risk of po-
lymerization.
• The position 5 (hot position) is mainly intended for applications with a risk of con-
densation .
2.4.2 Plate Heat Exchanger (Optional)
The machine is cooled by a cooling liquid circuit in the cylinder cover and cylinder.
The cooling liquid is cooled by a plate heat exchanger (PHE) which must be connect-
ed to the water main.
The cooling liquid pump (CLP) allows a recirculating flow in the cooling liquid cham-
ber.
2.5 Standard Features
2.5.1 Temperature Switch
The temperature switch monitors the operating temperature of the machine.
The machine must be stopped when the temperature switch trips (106 °C).
2.5.2 Thermometer
The thermometer allows a visual display of the cooling water temperature in the cool-
ing water chamber.

2 | Product Description
8 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
2.5.3 Sealing Systems
The machine is equipped with labyrinth seals on the motor side and suction side.
Other sealing systems are optionally available, see Mechanical Seals [►8] or PTFE
Shaft Seals [►8].
Sealing systems prevent the process gas going to the bearings chambers.
Depending on the application, the sealing systems efficiency can be improved with a
barrier gas system, see Barrier Gas System [►8].
2.6 Optional Accessories
2.6.1 Gas Ballast Valve
The gas ballast valve mixes the process gas with a limited quantity of ambient air to
counteract the condensation of vapour inside the machine.
The gas ballast valve has an influence on the ultimate pressure of the machine, see
Technical Data [►39].
2.6.2 Silencer
A silencer at the discharge connection (OUT) can be provided to reduce the exhaust
gas noise.
A non-return flap can be optionally added to the silencer.
2.6.3 Barrier Gas System
The barrier gas system allows the supply of compressed air or nitrogen into the motor
side shaft seals in order to improve the sealing efficiency.
2.6.4 Mechanical Seals
The sealing systems can be equipped with mechanical seals. The following variants
are possible:
– Oil lubricated single mechanical seals on the motor side and labyrinth seals on the
suction side.
– Oil lubricated single mechanical seals on the motor side and suction side.
– Gas lubricated double mechanical seals on the motor side and oil lubricated single
mechanical seals on suction side.
2.6.5 PTFE Shaft Seals
The sealing systems on the motor side can also be equipped with PTFE shaft seals.
2.6.6 Nitrogen Panel
The nitrogen panel fitted to the base frame allows the supply of nitrogen to a number
of different points on the machine.
Each device consists of a pressure regulator and a flow meter to adjust pressure and
volume flow separately.
The following devices are available:
– The barrier gas system for sealing systems on motor side. This device is equipped
with a flow switch integrated to the flow meter to switch off the machine if the nitro-
gen volume flow drops below the minimum set flow value.
– The dilution gas ballast prevents the formation of condensates or dilutes them, de-
pending on the application. The nitrogen is fed into the cylinder.

Transport | 3
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 9 / 44
– The purge gas system fitted at the inlet flange allows to flush the machine after
use or during operation. The nitrogen is fed into the inlet flange.
2.6.7 Pressure Switch (Barrier Gas)
The pressure switch monitors the barrier gas pressure. It is only available if the ma-
chine has been equipped with gas lubricated double mechanical seals.
The machine must be stopped if the barrier gas pressure is below 2.5 bar, see Wiring
Diagram Pressure Switch (Optional) [►25].
3 Transport
WARNING
Suspended load.
Risk of severe injury!
• Do not walk, stand or work under suspended loads.
WARNING
Lifting the machine using the motor eye bolt.
Risk of severe injury!
• Do not lift the machine using the eye bolt fitted to the motor. Only lift the machine as
shown.
NOTICE
In case the machine is already filled with oil.
Tilting a machine that is already filled with oil can cause large quantities of oil to
ingress into the cylinder.
• Drain the oil prior to every transport or always horizontally transport the machine.
• Make sure that the eyebolt(s) (EB) is/are in faultless condition, fully screwed in and
tightened by hand.
Machine weight:
see the technical data or the nameplate (NP)
• Check the machine for transport damage.
If the machine is secured to a base plate:

3 | Transport
10 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
• Remove the machine from the base plate.

Storage | 4
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 11 / 44
4 Storage
• Seal all apertures with adhesive tape or reuse provided caps.
If the machine is to be stored for more than 3 months:
• Wrap the machine in a corrosion inhibiting film.
• Store the machine indoors, dry, dust free and if possible in original packaging
preferably at temperatures between 5 ... 55 °C.
NOTICE
Long storage time.
Risk of damage to the machine!
• If the machine is equipped with oil lubricated mechanical seals, we recommend to
completely fill the oil chamber before a long storage, see “Oil filling” in chapter Oil
Change [►31]. This protects the mechanical seals during a long storage. Use the
standard pump oil, see chapter Oil [►39].
• Before restarting the machine, drain the oil to the normal oil level, see “Oil draining”
in chapter Oil Change [►31].
5 Installation
5.1 Installation Conditions
NOTICE
Use of the machine outside of the permitted installation conditions.
Risk of premature failure!
Loss of efficiency!
• Take care that the installation conditions are fully complied with.
• Make sure that the environment of the machine is not potentially explosive.
• Make sure that the ambient conditions comply with the Technical Data [►39].
• Make sure that the environmental conditions comply with the protection class of the
motor and the electrical instruments.
• Make sure that the installation space or location is vented such that sufficient cool-
ing of the machine is provided.
• Make sure that cooling air inlets and outlets of the motor fan are not covered or ob-
structed and that the cooling air flow is not affected adversely in any other way.
• Make sure that the oil sight glass (OSG) remains easily visible.
• Make sure that enough space remains for maintenance work.
• Make sure that the machine is placed or mounted horizontally, a maximum of 1° in
any direction is acceptable.
• Check the oil level, see Oil Level Inspection [►29].
If the machine is equipped with a plate heat exchanger (PHE):
• Check the cooling liquid level, see Cooling Liquid Level Inspection [►30].
• Make sure that the cooling water complies with the requirements, see Cooling Wa-
ter Connection [►14].
If the machine is installed at an altitude greater than 1000 meters above sea level:

5 | Installation
12 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
• Contact your Busch representative, the motor should be derated or the ambient
temperature limited.

Installation | 5
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 13 / 44
5.2 Connecting Lines / Pipes
• Remove all protective covers before installation.
• Make sure that the connection lines cause no stress on the machine‘s connection; if
necessary use flexible joints.
• Make sure that the line size of the connection lines over the entire length is at least
as large as the connections of the machine.
In case of very long connection lines it is advisable to use larger line sizes in order to
avoid a loss of efficiency. Seek advice from your Busch representative.
5.2.1 Suction Connection
WARNING
Unprotected suction connection.
Risk of severe injury!
• Do not put hand or fingers in the suction connection.
NOTICE
Ingress of foreign objects or liquids.
Risk of damage to the machine!
If the inlet gas contains dust or other foreign solid particles:
• Install a suitable filter (5micron or less) upstream from the machine.
Connection size(s):
– DN40 PN16, EN 1092-1 for NC 0100 B
– DN50 PN16, EN 1092-1 for NC 0200 B and NC 0300 B
If the machine is used as part of a vacuum system:
• Busch recommends the installation of an isolation valve in order to prevent the
machine from turning backwards.
5.2.2 Discharge Connection
Connection size(s):
At the machine discharge connection:
– Ø85 / 8 x M8
At the extra flange discharge connection (Optional):
– DN40 PN16, EN 1092-1 for NC 0100 B
– DN50 PN16, EN 1092-1 for NC 0200 B and NC 0300 B
At the silencer (SI) discharge connection (Optional):
– DN40 PN16, EN 1092-1 for NC 0100 B
– DN50 PN16, EN 1092-1 for NC 0200 B and NC 0300 B
• Make sure that the discharged gas will flow without obstruction. Do not shut off or
throttle the discharge line or use it as a pressurised air source.
• Make sure that the counter pressure (also termed back pressure) at the discharge
connection (OUT) does not exceed the maximum allowable discharge pressure,
see Technical Data [►39].

5 | Installation
14 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
5.2.3 Cooling Water Connection
Water-cooled version with direct cooling:
1
2
3
4
5
CWOCWITV
Thermostatic valve
adjustment
CWI Cooling water inlet CWO Cooling water outlet
TV Thermostatic valve
Water-cooled version with plate heat exchanger (optional):
CWOCWI PHE
CWI Cooling water inlet CWO Cooling water outlet
PHE Plate heat exchanger
• Connect the cooling water connections (CWI / CWO) to the water supply.
Connection size:
– DN15 PN10, DIN 2566 (CWI / CWO) with direct cooling
– G1/2, ISO 228-1 (CWI / CWO) with plate heat exchanger
• Make sure that the cooling water complies with the following requirements:
Supply capacity l/min 2 ... 4
Water pressure bar 3 ... 6 (direct cooling)
1...6(plate heat exchanger)
Supply temperature °C +10 ... +25
Required pressure differential across sup-
ply and return
bar ≥ 3 (direct cooling)
>0.5(plateheatexchanger)

Installation | 5
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 15 / 44
• To reduce the maintenance effort and ensure a long product lifetime we recom-
mend the following cooling water quality:
Hardness mg/l (ppm) < 90
Properties Clean & clear
PH value 7 ... 8
Particle size µm < 200
Chloride mg/l < 100
Electrical conductivity µS/cm ≤ 100
Free chloride mg/l < 0.3
Materials in contact with the cooling water Stainless steel, copper and cast iron
NOTE
Water hardness unit conversion.
1 mg/l (ppm) = 0.056 °dh (german degree) = 0.07 °e (english degree) = 0.1 °fH (french
degree)
5.2.4 Barrier Gas System Connection (Optional)
With nitrogen panel
PRVBGC MANFME, FS NIP
BGC Barrier gas connection FME Flow meter
FS Flow switch MAN Manometer
NIP Nitrogen panel PRV Pressure regulating valve
• Connect the barrier gas connection (BGC) to the gas supply.
Connection size:
– G1/4, ISO 228-1
• Electrically connect the flow switch (FS) of the flow meter, see Wiring Diagram Flow
Switch [►24].
If a pressure switch being installed:
• Electrically connect the pressure switch, see Wiring Diagram Pressure Switch
(Optional) [►25].

5 | Installation
16 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
• Make sure that the gas complies with the following requirements:
Gas type Dry nitrogen or air
Gas temperature °C 0 ... 60
Maximum gas pressure bar 13
Recommended pressure setting at the
pressure regulating valve (PRV)
bar 3
Filtration µm 5
Recommended flow rate
for labyrinth seals, oil lubricated single
mechanical seals and PTFE shaft
seals
SLM* 2.5 ... 3
Recommended flow rate
for gas lubricated double mechanical
seals
SLM* ≤1
Air quality (only for air) Acc. to ISO
8573-1
Class 5.4.4.
* standard litre per minute
5.2.5 Dilution Gas System Connection (Optional)
PRVDGC MANFME, FRNIP
DGC Dilution gas connection FME Flow meter
FR Flow regulator MAN Manometer
NIP Nitrogen panel PRV Pressure regulating valve
• Connect the dilution gas connection (DGC) to the gas supply.
Connection size:
– G1/4, ISO 228-1
• Electrically connect the solenoid valve (MV), see Wiring Diagram Solenoid Valve
[►24].
• Make sure that the gas complies with the following requirements:
Gas type Dry nitrogen
Gas temperature °C 0 ... 60
Maximum gas pressure bar 13
Recommended pressure setting at the
pressure regulating valve (PRV)
bar 0.5
Filtration µm 5
Recommended flow rate SLM* 20
* standard litre per minute

Installation | 5
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 17 / 44
5.2.6 Purge Gas System Connection (Optional)
PRVPGC MANFME, FRNIP MV INF
PGC Purge gas connection FME Flow meter
FR Flow regulator INF Inlet flange
MAN Manometer MV Solenoid valve
NIP Nitrogen panel PRV Pressure regulating valve
• Connect the purge gas connection to the gas supply.
Connection size:
– G1/4, ISO 228-1
• Electrically connect the solenoid valve (MV), see Wiring Diagram Solenoid Valve
[►24].
• Make sure that the gas complies with the following requirements:
Gas type Dry nitrogen
Gas temperature °C 0 ... 60
Maximum gas pressure bar 13
Recommended pressure setting at the
pressure regulating valve (PRV)
bar 0.5
Filtration µm 5
Recommended flow rate SLM* ≥ 40 for NC 0100-0200 B
* standard litre per minute
• Make sure that the gas complies with the following requirements:
Gas type Dry nitrogen
Gas temperature °C 0 ... 60
Maximum gas pressure bar 13
Recommended pressure setting at the
pressure regulating valve (PRV)
bar 0.5
Filtration µm 5
Recommended flow rate SLM* ≥ 40 for NC 0100-0200 B
≥ 50 for NC 0300 B
* standard litre per minute

5 | Installation
18 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
5.3 Filling Oil
NOTICE
Use of an inappropriate oil.
Risk of premature failure!
Loss of efficiency!
• Only use an oil type which has previously been approved and recommended by
Busch.
For oil type and oil capacity see Technical Data [►39] and Oil [►39].
1
2
Busch Oil
3
MAX
MIN
4
Check oil level
Oil filling at the motor side

Installation | 5
Instruction Manual COBRA NC 0100-0300 B WCV_EN_en 19 / 44
1
2
Busch Oil
3
MAX
MIN
4
Check oil level
Oil filling at the suction side
When the oil filling is achieved:
• Write down the oil change date on the sticker.
Last oil change
__ / __ / ____
Oil type see nameplate
Change interval see
instruction manual
If there is no sticker (part no. 0565 568 959) on the machine:
• Order it from your Busch representative.

5 | Installation
20 / 44 Instruction Manual COBRA NC 0100-0300 B WCV_EN_en
5.4 Filling Cooling Liquid
This step has to be carried out only if the machine is equipped with a plate heat ex-
changer.
For cooling liquid type and cooling liquid capacity see Technical Data [►39] and
Cooling Liquid [►39].
12
Cooling
liquid
Zitrec M-25
3
MAX
MIN
4
Check cooling liquid level
NC 0100 B NC 0200 B
NC 0300 B
NC 0200 B
NC 0300 B NC 0100 B
5.5 Liquid Flushing Device Installation (Optional)
LS1 FRLIFLV INFMVFLF LS2
FLF Flushing liquid fill plug FLV Flushing liquid vessel
FR Flow regulator INF Inlet flange
LI Level indicator LS Level switch
MV Solenoid valve