BUSCH COBRA User manual

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Instruction Manual
COBRA
Dry Screw Vacuum Pumps
NC 1500 B VR (Vapor Recovery)
0870573045/A0004_en / Original instructions / Modifications reserved 14/09/2021

Table of Contents
2 / 36 Instruction Manual COBRA NC 1500 B VR_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 Cooling ................................................................................................................. 6
2.4.2 Sealing Systems................................................................................................... 6
2.4.3 Liquid Return System ........................................................................................... 7
2.5 Optional Accessories ...................................................................................................... 8
2.5.1 Resistance Thermometer ..................................................................................... 8
2.6 P&ID "Piping and Instrumentation Diagram" ................................................................... 8
3 Transport ................................................................................................................................9
4 Storage....................................................................................................................................10
5 Installation ..............................................................................................................................11
5.1 Installation Conditions ..................................................................................................... 11
5.2 Connecting Lines / Pipes ................................................................................................ 11
5.2.1 Suction Connection .............................................................................................. 12
5.2.2 Discharge Connection .......................................................................................... 12
5.2.3 Cooling Liquid Connection ................................................................................... 12
5.3 Earth Connection ............................................................................................................ 13
5.4 Filling Oil ......................................................................................................................... 13
5.5 Fitting the Coupling ......................................................................................................... 15
5.5.1 Coupling Alignment .............................................................................................. 15
5.6 Electrical Connection ...................................................................................................... 16
5.6.1 Wiring Diagram Three-Phase Motor (Pump Drive) .............................................. 17
5.7 Electrical Connection of the Monitoring Devices............................................................. 18
5.7.1 Wiring Diagram Resistance Thermometer ........................................................... 18
5.8 Installation and Commissioning Parameters................................................................... 19
6 Commissioning ......................................................................................................................19
6.1 Start-Up ........................................................................................................................... 20
6.2 Switch Off ........................................................................................................................ 20
6.3 Restart Procedure ........................................................................................................... 20
7 Maintenance ...........................................................................................................................21
7.1 Maintenance Schedule.................................................................................................... 21
7.2 Oil Level Inspection......................................................................................................... 22
7.3 Oil Change ...................................................................................................................... 22
7.4 Checking the Liquid Return System................................................................................ 26
8 Overhaul..................................................................................................................................27
9 Decommissioning ..................................................................................................................27
9.1 Dismantling and Disposal................................................................................................ 27
10 Spare Parts .............................................................................................................................28
11 Troubleshooting.....................................................................................................................29
12 Technical Data........................................................................................................................31
13 Oil ............................................................................................................................................31

Table of Contents
Instruction Manual COBRA NC 1500 B VR_EN_en 3
14 EU Declaration of Conformity...............................................................................................32

1 | Safety
4 / 36 Instruction Manual COBRA NC 1500 B VR_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 1500 B VR_EN_en 5 / 36
2 Product Description
CLI
OSGODV
OUT
OFP
INJ
VES CLD
CLD
ODV
IN CLO
ECP
OFP
OSG MP
ECP
EB
EB
NP
CLD
MTB
MP
CLD Cooling liquid drain plug CLI Cooling liquid inlet connection
CLO Cooling liquid outlet connection EB Eye bolt
ECP Earth connection (machine) IN Suction connection
INJ Injection point LS Level switch
MP Magnetic plug MTB Motor terminal box
NP Nameplate ODV Oil drain valve
OFP Oil fill plug OSG Oil sight glass
OUT Discharge connection VES Liquid return system vessel
NOTE
Technical term.
In this instruction manual, we consider that the term ‘machine’ refers to the ‘vacuum
pump’.

2 | Product Description
6 / 36 Instruction Manual COBRA NC 1500 B VR_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 can be used to draw gas mixtures and hydrocarbon gases.
The machine is capable of maintaining ultimate pressure, see Technical Data [►31].
The machine is suitable for continuous operation.
Permitted environmental conditions, see Technical Data [►31].
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 equipped with a soft-starter or a variable-frequency drive.
2.4 Standard Features
2.4.1 Cooling
The machine is cooled by a cooling liquid circuit in the cylinder cover and cylinder.
The screw rotors are cooled by injection of cooling liquid into the cylinder.
2.4.2 Sealing Systems
Sealing systems prevent the process gas going to the bearings chambers.
The machine is equipped with oil lubricated single mechanical seal with labyrinth seal
on the motor side and oil lubricated single mechanical seal with lip seal on the suction
side.

Product Description | 2
Instruction Manual COBRA NC 1500 B VR_EN_en 7 / 36
2.4.3 Liquid Return System
The liquid return system allows any excess cooling liquid to be reinjected into the inlet
flange.

2 | Product Description
8 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
2.5 Optional Accessories
2.5.1 Resistance Thermometer
The resistance thermometer monitors the cooling liquid temperature. A second resist-
ance thermometer might be installed to monitor the exhaust gas temperature.
If a resistance thermometer is necessary to monitor the exhaust gas temperature, it
may be installed in either the exhaust outlet flange of the pump or in a suitable pre-
pared exhaust spool piece at a distance of < 100 mm from the pump outlet.
The machine must be stopped either when the cooling liquid temperature or when the
exhaust gas temperature reaches the trip value, see Wiring Diagram Resistance Ther-
mometer.
2.6 P&ID "Piping and Instrumentation Diagram"
IN
OUT
CLI
INJ
CLO
0101
TSA+
0102
TSA+
M
CPL
MOT
VES
= optional
CLI Cooling liquid inlet connection CLO Cooling liquid outlet connection
CPL Coupling IN Suction connection
INJ Injection point LS Level switch
MOT Motor OUT Discharge connection
TSA Resistance thermometer VES Liquid return system vessel

Transport | 3
Instruction Manual COBRA NC 1500 B VR_EN_en 9 / 36
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)
Transport with motor
l3 = ~230 mm
l1 = ~270 mm
l2 = ~245 mm

4 | Storage
10 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
Machine weight:
see the technical data or
the nameplate (NP)
Transport without motor
l1 = ~420 mm
l2 = ~330 mm
• 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 -20 ... 60 °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 [►22]. This protects the mechanical seals during a long storage. Use the
standard pump oil, see chapter Oil [►31].
• Before restarting the machine, drain the oil to the normal oil level, see “Oil draining”
in chapter Oil Change [►22].

Installation | 5
Instruction Manual COBRA NC 1500 B VR_EN_en 11 / 36
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 machine complies with local and national rules and safety regu-
lations, i.e. in case of installation in a potentially explosive environment.
• Make sure that the ambient conditions comply with the Technical Data [►31].
• 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 [►22].
• Make sure that the cooling liquid complies with the requirements, see Installation
and Commissioning Parameters [►19].
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.
5.2 Connecting Lines / Pipes
WARNING
The connection lines can build up an electrostatic charge.
Risk of severe injury!
Risk of explosion!
• The connection lines must be made out of conductive material or provisions must
be made against creating an electrostatic charge.
• 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 | Installation
12 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
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 PN16, EN 1092-1
– ANSI 150, 4” (optional)
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:
– DN80 PN16, EN 1092-1
– ANSI 150, 3” (optional)
• 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 [►31].
5.2.3 Cooling Liquid Connection
CLI CLO
INJ

Installation | 5
Instruction Manual COBRA NC 1500 B VR_EN_en 13 / 36
CLI Cooling liquid inlet connection CLO Cooling liquid outlet connection
INJ Injection point
Connection size:
– G1/2, ISO 228-1 (CLI / CLO)
– G1/2, ISO 228-1 (INJ)
5.3 Earth Connection
In order to prevent the machine from creating an electrostatic charge:
• Connect the earth connection of the machine (ECP)
Earth connection of
the machine (ECP)
5.4 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.

5 | Installation
14 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
For oil type and oil capacity see Technical Data [►31] and Oil [►31].
1
4
MAX
MIN
2
5
3
6
Busch Oil
Check
oil level
Oil filling at the motor side
4
1
2
3
MAX
MIN
Busch Oil
Check oil level
Oil filling at the suction side
When the oil filling is achieved:
• Write down the oil change date on the sticker.

Installation | 5
Instruction Manual COBRA NC 1500 B VR_EN_en 15 / 36
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.
5.5 Fitting the Coupling
2
3
E
1
Coupling hub (machine side)
Coupling hub (motor side)
Elastic insert
Radial screw
Max. admissible
torque: 10 Nm
Ring
Machine type Coupling size Value “E” (mm)
NC 1500 B Samiflex® A4CS 3.5
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.
• Align the motor, see Coupling Alignment [►15]
• Mount the elastic insert and ring.
For further coupling information, go to www.samiflex.se and download the instruction
manual of the Samiflex® coupling.
5.5.1 Coupling Alignment
The recommended radial and angular displacement/ alignment limitations for the CO-
BRA NC 1500 B VR pump/ coupling alignment should not exceed 0.01 mm in any di-
rection.

5 | Installation
16 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
5.6 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.
• Two earth connections are also available on the machine base frame, dia. 10.5 mm.
• Electrically connect the motor.
• Make sure that the machine is started either by a variable-frequency drive or by an
electrical soft starter unit.
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 [►31] 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).
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.

Installation | 5
Instruction Manual COBRA NC 1500 B VR_EN_en 17 / 36
5.6.1 Wiring Diagram Three-Phase Motor (Pump Drive)
Delta connection (low voltage): Star connection (high voltage):
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:
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 | Installation
18 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
5.7 Electrical Connection of the Monitoring Devices
NOTE
In order to prevent potential nuisance alarms, Busch allows that the control system is
configured with a time delay of 2 seconds.
NOTE
The accessories below are considered as standard.
If other specific components should be used, refer to the instruction manual of the ac-
cessory in question.
5.7.1 Wiring Diagram Resistance Thermometer
Part no.:
PT100: 0651 550 436
Transmitter: 0643536800
Supplier reference:
PT100: Albert Balzer AG
ref. TWBa-ADX50XG1/4X90DACB
Transmitter: Endress+Hauser
ref. TMT187-B41FJA
P&ID position:
TSA+/0101 “cooling liquid temp.”
TSA+/0102 “exhaust gas temp.”
Wiring with transmitter:
2
1
+
-
1
2
3
4
5
6
+
-
1 = Brown ; 2 = Blue
Wiring without transmitter:
1
2
3
4
1 and 2 = Red ; 3 and 4 = White
Electrical data:
Ui=30VDC; Ii=100mA; Pi=750mW; Li=0µH; Ci=0pF
4 ... 20 mA ► 0 ... 300 °C
Warning signal:
A warning signal can be set prior the trip signal.
Trip signal:
Ttrip (TSA+/0101) = 55°C ► 6.93 mA
Ttrip (TSA+/0102) = 80°C ► 8.27 mA

Commissioning | 6
Instruction Manual COBRA NC 1500 B VR_EN_en 19 / 36
5.8 Installation and Commissioning Parameters
• Make sure that the cooling liquid and the injection liquid comply with the following
requirements:
Cooling jacket and Injected cooling liquid
pressure requirements (CLI + INJ) (pres-
sure bar(g))
3.5 – 6 bar (g)
Cooling jacket flow rate (CLI) 18 l/min
Injected cooling liquid flow: Minimum (INJ) 2 l/min
Injected cooling liquid flow: Maximum*
(INJ)
3 … 6 l/min
Ambient air temperature range (standard) -20 … 40 °C
Ambient air temperature range (high tem-
perature version, refer to machine name-
plate) Specific motors
-20 … 60 °C
Cooling liquid supply temperature 10 … 40 °C
Maximum allowable gas inlet temperature 70 °C
Maximum exhaust gas temperature (TSA
+/0102)
80 °C
Recommended exhaust gas temperature 60 °C
Maximum cooling liquid outlet temperature
(TSA+/0101)
55 °C
Maximum operational temperature differ-
ence between cooling jacket and exhaust
gas outlet
70 °C
* The quantity of cooling liquid injected should be sufficient to ensure that at no time
during the operation of the machine, the maximum exhaust gas outlet temperature is
exceeded
Should the operating conditions of your machine fall outside of the recommended pa-
rameters as outlined, please contact your local Busch agency for advice.
6 Commissioning
NOTICE
The machine can be shipped without oil.
Operation without oil will ruin the machine in short time!
• Prior to commissioning, the machine must be filled with oil, see Filling Oil [►13].
NOTICE
Lubricating a dry running machine (compression chamber).
Risk of damage to the machine!
• Do not lubricate the compression chamber of the machine with oil or grease.
CAUTION
During operation the surface of the machine may reach temperatures of more than
70°C.
Risk of burns!
• Avoid contact with the machine during and directly after operation.

6 | Commissioning
20 / 36 Instruction Manual COBRA NC 1500 B VR_EN_en
CAUTION
Noise of running machine.
Risk of damage to hearing!
If persons are present in the vicinity of a non noise insulated machine over extended
periods:
• Make sure that ear protection is being used.
6.1 Start-Up
• Make sure that the installation conditions (see Installation Conditions [►11]) are
met.
• Turn on the cooling liquid supply (CLI) and adjust flow rates, see Cooling Liquid
Connection [►12].
• Switch on the machine.
• Make sure that the maximum permissible number of starts does not exceed 6 starts
per hour. Those starts should be spread within the hour.
• Make sure that the operating conditions are met, see Installation and Commission-
ing Parameters [►19] and Technical Data [►31].
• Open the cooling liquid injection, see Cooling Liquid Connection [►12].
• After a few minutes of operation, perform an Oil Level Inspection [►22].
As soon as the machine is operated under normal operating conditions:
• Measure the motor current and record it as reference for future maintenance
and troubleshooting work.
6.2 Switch Off
• Vent the machine at a pressure between atmospheric pressure and 650 hPa.
• Close the cooling liquid injection.
• Let the machine run for 1 minute.
• Stop the machine
• Close the cooling liquid supply.
6.3 Restart Procedure
Prior to restart the system, ascertain the reason for the emergency stop.
Resolve the problem.
• With the machine electrically isolated from the power supply and vacuum system,
all appropriate safety precautions, warning boards, safety equipment and perimeter
must put into place.
• Drain and collect any residual liquids from the pumping chamber, in compliance
with all local restrictions and requirements.
Make sure that the machine is empty. Replace all previously removed drain plugs.
When the work has been completed follow the procedure Start-Up [►20].
• Remove the warning board and safety perimeter.
• Check the oil levels, see Oil Level Inspection [►22].
• Connect the machine to the power supply.