BUSCH COBRA NC 0630 C User manual

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Instruction Manual
COBRA
Dry Screw Vacuum Pumps
NC 0630 C
(air-cooled version)
0870567093/A0004_en / Original instructions / Modifications reserved 14/09/2021

Table of Contents
2 / 40 Instruction Manual COBRA NC 0630 C ACV_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 .................................................................................................................. 6
2.4 Standard Features .......................................................................................................... 6
2.4.1 Air Cooling............................................................................................................ 6
2.4.2 Temperature Switch ............................................................................................. 7
2.4.3 Thermometer ........................................................................................................ 7
2.4.4 Sealing Systems................................................................................................... 7
2.5 Optional Accessories ...................................................................................................... 7
2.5.1 Inlet Filter.............................................................................................................. 7
2.5.2 Gas Ballast Valve ................................................................................................. 7
2.5.3 Silencer ................................................................................................................ 7
2.5.4 Barrier Gas System .............................................................................................. 7
2.5.5 Mechanical Seals ................................................................................................. 7
2.5.6 Nitrogen Panel...................................................................................................... 8
2.5.7 Liquid Flushing Device ......................................................................................... 8
3 Transport ................................................................................................................................8
4 Storage....................................................................................................................................9
5 Installation ..............................................................................................................................10
5.1 Installation Conditions ..................................................................................................... 10
5.2 Connecting Lines / Pipes ................................................................................................ 11
5.2.1 Suction Connection .............................................................................................. 11
5.2.2 Discharge Connection .......................................................................................... 11
5.2.3 Barrier Gas System Connection (Optional) .......................................................... 12
5.2.4 Dilution Gas System Connection (Optional)......................................................... 13
5.2.5 Purge Gas System Connection (Optional) ........................................................... 14
5.3 Filling Oil ......................................................................................................................... 14
5.4 Filling Cooling Liquid ....................................................................................................... 16
5.5 Liquid Flushing Device Installation (Optional) ................................................................. 17
5.6 Fitting the Coupling ......................................................................................................... 17
5.7 Electrical Connection ...................................................................................................... 18
5.7.1 Wiring Diagram Three-Phase Motor (Pump Drive) .............................................. 19
5.7.2 Wiring Diagram Solenoid Valve (Optional)........................................................... 20
5.8 Electrical Connection of the Heat Exchanger Fan Motor ................................................ 20
5.8.1 Wiring Diagram Heat Exchanger Fan Motor ........................................................ 20
5.9 Electrical Connection of the Monitoring Devices............................................................. 21
5.9.1 Wiring Diagram Temperature Switch ................................................................... 21
5.9.2 Wiring Diagram Flow Switch (Optional)................................................................ 21
5.9.3 Wiring Diagram Level Switch (Optional)............................................................... 22
6 Commissioning ......................................................................................................................22
6.1 Conveying Condensable Vapours................................................................................... 23
6.2 Liquid Flushing Procedure .............................................................................................. 24
6.3 Gas Purging Procedure................................................................................................... 24
7 Maintenance ...........................................................................................................................24
7.1 Maintenance Schedule.................................................................................................... 25
7.2 Oil Level Inspection......................................................................................................... 26
7.3 Cooling Liquid Level Inspection ...................................................................................... 26
7.4 Replacing the Gas Ballast Filter (Optional) ..................................................................... 26

Table of Contents
Instruction Manual COBRA NC 0630 C ACV_EN_en 3
7.5 Oil Change ...................................................................................................................... 27
7.6 Cooling Liquid Change.................................................................................................... 30
8 Overhaul..................................................................................................................................31
9 Decommissioning ..................................................................................................................31
9.1 Dismantling and Disposal................................................................................................ 31
10 Spare Parts .............................................................................................................................32
11 Troubleshooting.....................................................................................................................32
12 Technical Data........................................................................................................................35
13 Cooling Liquid........................................................................................................................35
14 Oil ............................................................................................................................................35
15 EU Declaration of Conformity...............................................................................................36

1 | Safety
4 / 40 Instruction Manual COBRA NC 0630 C ACV_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 0630 C ACV_EN_en 5 / 40
2 Product Description
EB IN
OUT
PMR CLP
SI
OFPSV
ODP, MPNP
OUT
CLF EB OFP
CD
TM
GB ODP CLD
OSG
CLV1
TS
OSG
MP
MTB
AF AHECLV2
AHE Air-water heat exchanger AF Axial fan
CD Condensate drain CLD Cooling liquid drain plug
CLF Cooling liquid fill plug CLG Cooling liquid sight glass
CLP Cooling liquid pump CLV1 Cooling liquid vent plug (machine)
CLV2 Cooling liquid vent valve (heat exchanger) EB Eye bolt
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 PMR Plug for manual rotation of rotors
SI Silencer SV Safety valve
TM Thermometer TS Temperature switch
NOTE
Technical term.
In this instruction manual, we consider that the term ‘machine’ refers to the ‘vacuum
pump’.

2 | Product Description
6 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
NOTE
Illustrations
In this instruction manual the illustrations may differ from the machine appearance.
2.1 Operating Principle
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 [►35].
The machine is suitable for continuous operation.
Permitted environmental conditions, see Technical Data [►35].
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 Standard Features
2.4.1 Air Cooling
The machine is cooled by a cooling liquid circuit in the cylinder cover and cylinder.
The cooling liquid pump (CLP) allows a recirculating flow in the cooling liquid cham-
ber.
The cooling liquid is cooled by an air-water heat exchanger (AHE).

Product Description | 2
Instruction Manual COBRA NC 0630 C ACV_EN_en 7 / 40
A motor driven fan, integrated to the heat exchanger, allows the cooling air to be
drawn through the heat exchanger. See Electrical Connection of the Heat Exchanger
Fan Motor [►20].
2.4.2 Temperature Switch
The temperature switch monitors the oil temperature of the machine.
The machine must be stopped when the temperature switch trips (100 °C).
2.4.3 Thermometer
The thermometer allows a visual display of the cooling liquid temperature.
2.4.4 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 [►7].
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 [►7].
2.5 Optional Accessories
2.5.1 Inlet Filter
The inlet filter protects the machine against dust and other solids in the process gas.
The inlet filter is available with a paper cartridge.
2.5.2 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 [►35].
2.5.3 Silencer
A silencer at the discharge connection (OUT) can be provided to reduce the exhaust
gas noise.
2.5.4 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.
This device is available either with or without nitrogen panel.
2.5.5 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.

3 | Transport
8 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
– Oil lubricated single mechanical seals on the motor side and suction side.
2.5.6 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 solenoid valve to open or close the gas circuit, 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.
– 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.
2.5.7 Liquid Flushing Device
The liquid flushing device allows the machine to be flushed with the appropriate liquid
according to the process type. The system consists of a solenoid valve which enables
to open and close the flushing liquid circuit.
Furthermore, two level switches (LS1 and LS2) monitor the flushing liquid quantity.
Upper level switch (LS1 ► Lalarm) Early warning
Lower level switch (LS2 ► Ltrip) Trip, the flushing must be stopped
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.

Storage | 4
Instruction Manual COBRA NC 0630 C ACV_EN_en 9 / 40
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:
• Remove the machine from the base plate.
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 [►27]. This protects the mechanical seals during a long storage. Use the
standard pump oil, see chapter Oil [►35].
• Before restarting the machine, drain the oil to the normal oil level, see “Oil draining”
in chapter Oil Change [►27].

5 | Installation
10 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
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.
~20 cm
~20 cm
~50 cm
~50 cm
• Make sure that the environment of the machine is not potentially explosive.
• Make sure that the ambient conditions comply with the Technical Data [►35].
• 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 are not covered or obstructed 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 [►26].
• Check the cooling liquid level, see Cooling Liquid Level Inspection [►26].
If the machine is installed at an altitude greater than 1000 meters above sea level:
• Contact your Busch representative, the motor should be derated or the ambient
temperature limited.

Installation | 5
Instruction Manual COBRA NC 0630 C ACV_EN_en 11 / 40
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):
– DN100 ISO-K, DIN 28404
If a purge gas system or a liquid flushing device being installed:
– DN100 PN16, EN 1092-1
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:
– DN100 ISO-K, DIN 28404
At the silencer (SI) discharge connection (two optional versions available):
– DN80 PN16 + ANSI/ASME B16.5-3” class 150 lbs
– R3
• 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 [►35].

5 | Installation
12 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
5.2.3 Barrier Gas System Connection (Optional)
Without nitrogen panel
PRV FRBGCMANFME
BGC Barrier gas connection FME Flow meter
FR Flow regulator MAN Manometer
PRV Pressure regulating valve
With nitrogen panel
PRV MVBGC MANFME, FS NIP
BGC Barrier gas connection FME Flow meter
FS Flow switch MAN Manometer
MV Solenoid valve NIP Nitrogen panel
PRV Pressure regulating valve
• Connect the barrier gas connection (BGC) to the gas supply.
Connection size:
– G1/4, ISO 228-1
Version with nitrogen panel:
• Electrically connect the solenoid valve (MV), see Wiring Diagram Solenoid
Valve [►20].
• Electrically connect the flow switch (FS) of the flow meter, see Wiring Diagram
Flow Switch [►21].

Installation | 5
Instruction Manual COBRA NC 0630 C ACV_EN_en 13 / 40
• 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 SLM* 3,5 ... 5,5
Air quality (only for air) Acc. to ISO
8573-1
Class 5.4.4.
* standard litre per minute
5.2.4 Dilution Gas System Connection (Optional)
PRV MVDGC MANFME, FR NIP
DGC Dilution gas connection FME Flow meter
FR Flow regulator MAN Manometer
MV Solenoid valve 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
[►20].
• 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 2.5
Filtration µm 5
Recommended flow rate SLM* 30
* standard litre per minute

5 | Installation
14 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
5.2.5 Purge Gas System Connection (Optional)
PRV MVPGC MANFME, FR INFNIP
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
[►20].
• 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 2.5
Filtration µm 5
Recommended flow rate SLM* ≥ 100
* standard litre per minute
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.

Installation | 5
Instruction Manual COBRA NC 0630 C ACV_EN_en 15 / 40
For oil type and oil capacity see Technical Data [►35] and Oil [►35].
1
2
Busch Oil
3
MAX
MIN
4
Check oil level
Oil filling at the motor side
1
2
Busch Oil
3
MAX
MIN
4
Check oil level
Oil filling at the suction side

5 | Installation
16 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
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.
5.4 Filling Cooling Liquid
For cooling liquid type and cooling liquid capacity see Technical Data [►35] and
Cooling Liquid [►35].
1
4
6
3
Cooling
liquid
Zitrec M-25
5
Cooling
liquid
Zitrec M-25
2
7
Resume cooling liquid filling
Close the
cooling liquid
vent valve
(CLV2) when the
cooling liquid is
spilling out
Radiator vent
valve key
Fill up to the top of
the vent orifice

Installation | 5
Instruction Manual COBRA NC 0630 C ACV_EN_en 17 / 40
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
• Electrically connect the solenoid valve (MV), see Wiring Diagram Solenoid Valve
[►20].
• Electrically connect the two level switches (LS), see Wiring Diagram Level Switch
[►22].
• Fill the flushing liquid vessel (FLV) with a process compatible flushing liquid.
5.6 Fitting the Coupling
E
Coupling hub (machine side) Coupling hub (motor side)Coupling spider
Radial screw
Max. admissible
torque: 10 Nm
Machine type Coupling size Value “E” (mm)
NC 0600 C ROTEX® 42 26
NC 0630 C
NC 0630 C ROTEX® 48 28

5 | Installation
18 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
In case of a machine delivery without motor:
• Fit the second coupling hub on the motor shaft (separately delivered).
• Axially adjust the hub in such a way until value "E" is reached.
• When the coupling adjustment is done, lock the coupling hub by tightening the
radial screw.
• Mount the motor on the machine by including the coupling spider.
For further coupling information, go to www.ktr.com and download the instruction man-
ual of the ROTEX® coupling.
5.7 Electrical Connection
DANGER
Live wires.
Risk of electrical shock.
• Electrical installation work must only be executed by qualified personnel.
• Make sure that the power supply for the motor is compatible with the data on the
nameplate of the motor.
• The electrical installation must comply with applicable national and international
standards.
• Provide a lockable disconnect switch on the power line so that the machine is com-
pletely secured during maintenance tasks.
• Provide an overload protection according to EN 60204-1 for the motor.
• Make sure that the motor of the machine will not be affected by electric or electro-
magnetic disturbance from the mains; if necessary seek advice from Busch.
• Connect the protective earth conductor.
• Electrically connect the motor.
NOTICE
The admissible motor nominal speed exceeds the recommendation.
Risk of damage to the machine!
• Check the admissible motor nominal speed (nmax) on the nameplate of the machine
(NP).
• Make sure to comply with it.
• Consult the Technical Data [►35] to get more information.
NOTICE
The motor frequency is below 20 Hz.
Risk of damage to the machine!
• The motor nominal speed must always be higher than 1200 min-1 (20 Hz).

Installation | 5
Instruction Manual COBRA NC 0630 C ACV_EN_en 19 / 40
NOTICE
Incorrect connection.
Risk of damage to the motor!
• The wiring diagrams given below are typical. Check the inside of the terminal box
for motor connection instructions/diagrams.
5.7.1 Wiring Diagram Three-Phase Motor (Pump Drive)
Delta connection (low voltage): Star connection (high voltage):
Double star connection, multi-voltage
motor with 12 pins (low voltage):
4
4
4
Star connection, multi-voltage motor
with 12 pins (high voltage):
4
4
4
Delta connection, multi-voltage motor
with 12 pins (middle voltage):
4
4
4
NOTICE
Incorrect direction of rotation.
Risk of damage to the machine!
• Operation in the wrong direction of rotation can destroy the machine in a short time!
Prior to start-up, ensure that the machine is operated in the right direction.
The intended rotation direction of the motor is defined by the illustration below:

5 | Installation
20 / 40 Instruction Manual COBRA NC 0630 C ACV_EN_en
IN
• Jog the motor briefly.
• Watch the fan wheel of the motor and determine the direction of rotation just before
the fan wheel stops.
If the rotation of the motor must be changed:
• Switch any two of the motor phase wires.
5.7.2 Wiring Diagram Solenoid Valve (Optional)
Part no.: 0654 000 092
U = 24 VDC ; Pmax = 8 W
Contact: Normally closed
2 (-)
1 (+)
PE
5.8 Electrical Connection of the Heat Exchanger
Fan Motor
DANGER
Live wires.
Risk of electrical shock.
• Electrical installation work must only be executed by qualified personnel.
• Make sure that the power supply for the fan motor of the heat exchanger (AHE) is
compatible with the data on the nameplate of the heat exchanger.
• Provide an overload protection according to EN 60204-1 for the fan motor.
• Electrically connect the fan motor of the heat exchanger.
• Make sure that the fan motor is connected such that is running when the machine is
started.
5.8.1 Wiring Diagram Heat Exchanger Fan Motor
230/400 VAC fan motor version:
Delta connection (low voltage): Star connection (high voltage):
U1 = Black ; V1 = Blue ; W1 = Brown ; U2 = Green ; V2 = White ; W2 = Yellow
U = 230/400 VAC 50 Hz ; I = 0.9/0.5 A
U = 230/400 VAC 60 Hz ; I = 0.95/0.54 A
P = 0.195 kW