BUSCH COBRA NX 0450 A User manual

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COBRA
Dry Screw Vacuum Pumps
NX 0450 A, NX 0650 A
Water-Cooled Version (WCV)
Instruction Manual
0870565358 | B0008_en-US | Original instructions 11/3/2022

Table of Contents
2 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
Table of Contents
1 Safety..................................................................................................................................................................... 4
2 Product Description............................................................................................................................................. 5
2.1 Operating Principle ............................................................................................................................................. 6
2.2 Intended Use ....................................................................................................................................................... 6
2.3 Start Controls....................................................................................................................................................... 7
2.4 Standard Features............................................................................................................................................... 7
2.4.1 Water Cooling........................................................................................................................................ 7
2.4.2 Temperature Switch ............................................................................................................................. 7
2.4.3 Sealing Systems..................................................................................................................................... 7
2.5 Optional Accessories........................................................................................................................................... 7
2.5.1 Gas Ballast Valve ................................................................................................................................... 7
2.5.2 Silencer................................................................................................................................................... 7
2.5.3 Barrier Gas System ............................................................................................................................... 7
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 .......................................................................................................................... 12
5.2.3 Cooling Water Connection................................................................................................................... 13
5.2.4 Barrier Gas System Connection (Optional) ........................................................................................ 14
5.3 Filling Oil............................................................................................................................................................... 15
6 Electrical Connection........................................................................................................................................... 17
6.1 Machine delivered without Variable Speed Drive ........................................................................................... 17
6.2 Machine delivered with a Variable Speed Drive (Option)............................................................................... 19
6.3 Wiring Diagram Three-Phase Motor (Pump Drive)......................................................................................... 20
6.4 Electrical Connection of the Monitoring Devices ............................................................................................ 21
6.4.1 Wiring Diagram Temperature Switch................................................................................................. 21
7 Commissioning..................................................................................................................................................... 22
7.1 Conveying Condensable Vapors........................................................................................................................ 22
8 Maintenance......................................................................................................................................................... 24
8.1 Maintenance Schedule ....................................................................................................................................... 25
8.2 Oil Level Inspection............................................................................................................................................. 26
8.3 Cleaning the Inlet Screen ................................................................................................................................... 26
8.4 Cleaning the Gas Ballast Filter (Optional)......................................................................................................... 27
8.5 Oil Change............................................................................................................................................................ 27
9 Overhaul................................................................................................................................................................ 30
10 Decommissioning................................................................................................................................................. 31
10.1 Dismantling and Disposal .................................................................................................................................. 31
11 Spare Parts............................................................................................................................................................ 32
12 Troubleshooting................................................................................................................................................... 33
13 Technical Data...................................................................................................................................................... 35
14 Oil........................................................................................................................................................................... 36
15 EU Declaration of Conformity............................................................................................................................. 37

Table of Contents
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 3 | 40
16 UK Declaration of Conformity ............................................................................................................................ 38

1 | Safety
4 | 40 Instruction Manual COBRA NX 0450-0650 A 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 anything 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 methods. Never-
theless, residual risks may remain, as described in the following chapters and in accordance with the
chapter Intended Use [➔6]. This instruction manual highlights potential hazards where appropri-
ate. 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 injuries.
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 trou-
ble-free operation.

Product Description | 2
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 5 | 40
2 Product Description
IN, IS
OUT
PMR MPEB
BGR MTBCWD
SI
OSG
BGFOFPTSCWO
BGCBGMODP
GBOFP
OSGCWDODP
CWI
NP MP
OUTCD
Description
IN Suction connection (Inlet) OUT Discharge connection (Outlet)
BGC Barrier gas connection BGF Barrier gas flow meter
BGM Barrier gas manometer BGR Barrier gas pressure regulator
CD Condensate drain CWD Cooling water drain plug
CWI Cooling water inlet CWO Cooling water outlet
EB Eye bolt GB Gas ballast valve
IS Inlet screen MP Magnetic plug
MTB Motor terminal box NP Nameplate
ODP Oil drain plug OFP Oil fill plug
OSG Oil sight glass PMR Plug for manual rotation of rotors
SI Silencer 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 NX 0450-0650 A WCV_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 rotate inside the cylinder. The pumped medium is trapped between the cylinder
and screw chambers, compressed, and transported to the gas outlet. During the compression pro-
cess, the two screw rotors do not come into contact with each other or with the cylinder. There is no
need for a lubrication or an operating fluid in the compression chamber.
2.2 Intended Use
WARNING
In case of foreseeable misuse outside the intended use of the machine.
Risk of injuries!
Risk of damages to the machine!
Risk of damages to the environment!
●Make sure to follow all instructions described in this manual.
The machine is intended for the suction of air and other dry, non-aggressive, non-toxic and non-ex-
plosive 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.
The machine is suitable for continuous operation.
Permitted environmental conditions, see Technical Data.

Product Description | 2
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 7 | 40
NOTICE
Chemical compatibility of the process gases with the machine component materials.
Risk of corrosion inside the compression chamber which can reduce performance and its life-
time!
●Check if the process gases are compatible with those following materials:
- Cast iron
- Steel
- Aluminium
- Fluoroelastomer (FKM/FPM)
●In doubt, please contact your Busch representative.
2.3 Start Controls
The machine comes without start controls. The control of the machine is to be provided in the
course of installation.
The machine can be equipped with a variable speed drive (option).
2.4 Standard Features
2.4.1 Water Cooling
The machine is cooled by a cooling water circuit in the cylinder cover and cylinder.
2.4.2 Temperature Switch
The temperature switch monitors the cooling water temperature of the machine.
The temperature switch has two switch points:
Switch point 1 (T1) Early warning
Switch point 2 (T2) Trip, the machine must be stopped
2.4.3 Sealing Systems
The machine is equipped with labyrinth seals on the motor side and suction side.
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 sys-
tem, see Barrier Gas System [➔7].
2.5 Optional Accessories
2.5.1 Gas Ballast Valve
The gas ballast valve mixes the process gas with a limited quantity of ambient air to counteract the
condensation of vapor inside the machine.
The gas ballast valve has an influence on the ultimate pressure of the machine, see Technical Data.
2.5.2 Silencer
A silencer at the discharge connection (OUT) can be provided to reduce the exhaust gas noise.
2.5.3 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.

3 | Transport
8 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
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.
●To find out the weight of the machine, refer to the chapter Technical Data or the nameplate (NP).
●Make sure that the eye bolt(s) (EB) is/are in faultless condition, fully screwed in and tightened by
hand.
●Make sure that each of the slings used to lift the machine has a minimum length of 400 mm.
●Make sure that the length of each sling is exactly the same.
●Check the machine for transport damage.
If the machine is secured to a base plate:
●Remove the machine from the base plate.

Storage | 4
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 9 | 40
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.

5 | Installation
10 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_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
~50 cm
~20 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.
●Make sure that the environmental conditions comply with the protection class of the motor and
the electrical elements.
●Make sure that the installation space or location is vented such that sufficient cooling of the ma-
chine is provided.
●Make sure that cooling air inlets and outlets of the motor fan 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 deviation of 1° in any
direction is acceptable.
●Check the oil level, see Oil Level Inspection [➔26].
●Make sure that the cooling water complies with the requirements, see Cooling Water Connection
[➔13].
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 NX 0450-0650 A WCV_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 connection of the machine; if neces-
sary 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 long connection lines, it is advisable to use larger line sizes in order to avoid a loss of effi-
ciency. 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):
– G3
– ISO DN100, DIN 28404
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 | Installation
12 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
5.2.2 Discharge Connection
1
Description
1 Discharge variants (without silencer)
NOTICE
Discharge gas flow obstructed.
Risk of damage to the machine!
●Make sure that the discharged gas will flow without obstruction. Do not shut off or throttle the
discharge line or use it as a pressurized air source.
Connection size(s):
At the machine discharge connection:
– G2 for NX 0450 A, horizontal (orientable 180°)
– G3 for NX 0650 A, horizontal (orientable 180°)
– DN63 ISO-K, DIN 28404 for NX 0450 A, vertical (without discharge elbow)
– ISO DN100, DIN 28404 for NX 0650 A, vertical (without discharge elbow)
At the silencer (SI) discharge connection (Optional):
– G2 for NX 0450 A, G3 for NX 0650 A, horizontal
●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.

Installation | 5
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 13 | 40
5.2.3 Cooling Water Connection
CWI CWO
Description
CWI Cooling water inlet CWO Cooling water outlet
●Connect the cooling water connections (CWI / CWO) to the water supply.
Connection size:
– G1/2, ISO 228-1 (CWI / CWO)
●Make sure that the cooling water complies with the following requirements:
Supply capacity l/min 4...10forNX0450A
6...14forNX0650A
Water pressure bar 1 ... 6
Supply temperature °C +10 ... +30
Required pressure differential across supply
and return
bar ≥ 1
●To reduce the maintenance effort and ensure a long product lifetime we recommend the follow-
ing 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 and cast iron

5 | Installation
14 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
NOTE
Water hardness unit conversion.
1 mg/l (ppm) = 0.056 °dh (german degree) = 0.07 °e (english degree) = 0.1 °fH (french degree)
●Make sure that the water flow of the cooling water at the outlet (CWO) is monitored.
If it is not possible, Busch recommends calibrating the flow with one or two orifices depending on
the water pressure, see the following table:
Diameter of the orifice Differential water pressure
NX 0450 A NX 0650 A
No calibration n/a 1 … 2 bar
4 mm at the cooling water outlet 1 … 2 bar 2 … 3 bar
4 mm at the cooling water inlet and outlet 2 … 6 bar 3 … 6 bar
5.2.4 Barrier Gas System Connection (Optional)
PRV FMEBGCMAN
Description
BGC Barrier gas connection FME Flow meter
MAN Manometer PRV Pressure regulating valve
●Connect the barrier gas connection (BGC) to the gas supply.
Connection size:
– G1/4, ISO 228-1
●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

Installation | 5
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 15 | 40
Recommended pressure setting at the pres-
sure regulating valve (PRV)
bar(a) 3
Filtration µm 5
Recommended flow rate SLM (standard li-
ter per minute)
NX0450A: 10 ... 15 - NX0650A:
15 ... 20
Air quality (only for air) Acc. to ISO
8573-1
Class 5.4.4.
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 and Oil [➔36].

5 | Installation
16 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_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.

Electrical Connection | 6
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 17 | 40
6 Electrical Connection
DANGER
Live wires.
Risk of electrical shock.
●Electrical installation work must only be executed by qualified personnel.
CURRENT PROTECTION OF THE CUSTOMER INSTALLATION:
DANGER
Missing current protection.
Risk of electrical shock.
●Current protection according to EN 60204-1 must be insured by the customer on its installation.
●The electrical installation must comply with the applicable national and international standards.
NOTICE
Electromagnetic compatibility.
●Make sure that the motor of the machine will not be affected by electric or electro- magnetic dis-
turbance from the mains, if necessary seek advice from Busch.
●Make sure that the EMC of the machine is compliant with the requirements of your supply net-
work system, if necessary provide further interference suppression (EMC of the machine, see EU
Declaration of Conformity [➔37] or UK Declaration of Conformity [➔38]).
6.1 Machine delivered without Variable Speed Drive
DANGER
Live wires.
Risk of electrical shock.
●Electrical installation work must only be executed by qualified personnel.
NOTE
The operation with variable speed, i.e. with a variable speed drive, is allowed as long as the
motor is capable and the permitted motor speed range is respected (see Technical Data).
Seek advice from your Busch representative.
●Make sure that the power supply for the motor is compatible with the data on the nameplate of
the motor.
●If the machine is equipped with a power connector, install a residual current protective device to
protect persons in case of isolation default.

6 | Electrical Connection
18 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
●Busch recommends installing a type B residual protective device suitable for the electrical in-
stallation.
●Provide a lockable disconnect switch or an emergency stop switch on the power line so that the
machine is completely secured in case of an emergency situation.
●Provide a lockable disconnect switch on the power line so that the machine is completely secured
during maintenance tasks.
●Provide an overload protection according to EN 60204-1 for the motor.
●Connect the protective earth conductor.
●Electrically connect the motor.
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
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 to get more information.
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 con-
nection instructions/diagrams.

Electrical Connection | 6
Instruction Manual COBRA NX 0450-0650 A WCV_EN_en 19 | 40
6.2 Machine delivered with a Variable Speed Drive
(Option)
DANGER
Live wires. Carry out any work on the variable speed drive and motor.
Risk of electrical shock!
●Electrical installation work must only be executed by qualified personnel.
DANGER
Maintenance work without disconnecting the variable speed drive.
Risk of electrical shock.
●Disconnect and isolate the variable speed drive before attempting any work on it.
High voltages are present at the terminals and within the variable speed drive for up to 10 min-
utes after disconnection of the electrical supply.
●Always ensure by using a suitable multimeter that no voltage is present on any drive power termi-
nals prior to commencing any work.
●Make sure that the power supply for the drive is compatible with the data on the nameplate of
the variable speed drive.
●If the machine is equipped with a power connector, install a residual current protective device to
protect persons in case of isolation default.
●Busch recommends installing a type B residual protective device suitable for the electrical in-
stallation.
●If the variable speed drive is not equipped with a lockable disconnect switch, provide it on the
power line so that the machine is completely secured during maintenance tasks.
●Provide an overload protection according to EN 60204-1.
●Busch recommends installing a C-curve circuit breaker.
●Connect the protective earth conductor.
●Electrically connect the Variable Speed Drive (VSD).
NOTICE
The admissible motor speed exceeds the recommendation.
Risk of damage to the machine!
●Check the admissible motor speed range, see Technical Data.
NOTICE
Incorrect connection.
Risk of damage to the variable speed drive!
●The wiring diagrams given below are typical. Check the connection instructions/diagrams.

6 | Electrical Connection
20 | 40 Instruction Manual COBRA NX 0450-0650 A WCV_EN_en
6.3 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: