flights of the screws and the pump body. The gases are conveyed by
the rotation of the screws to the exhaust, where they are discharged.
The COBRA NW screw vacuum pumps are driven by water-cooled
motors.
Oil circuit
Since the complete operating principle works without contact, no oil
circuit is needed in the work area.
Cooling
The vacuum pump is cooled by
–
a cooling water circuit (4) in the cylinder and motor. The cooling
water flow is preset at 1 l/min at the factory and can be adjusted
with valve CWR. This cooling water circuit is used to cool the
motor of the pump, the frequency inverter and also the body of
the NW pump.
NOTE
:
The
COBRA
BC
vacuum
pumps
are
always
delivered
without
oil
and
without
cooling
water.
Operation
without
these
coolants
can
result
in
damage
to
the
vacuum
pump.
Nitrogen system
The nitrogen system performs t
wo
mai
n functions:
–
nitrogen is used as sealing gas. The nitrogen is injected between
the
transmission and the process gas to achieve good closeness.
The
Nitrogen flow used for the sealing is set by two
orifice plates
(
f
).
W
ith
a
pressure of 1,5 bar, the flow is around 8-10 l/min.
–
nitrogen is used as dilution gas as an option. It is injected inside the
cylinder which located in middle of screw. Nitrogen flow injected
in
the middle hole is preset at 2 - 5 l/ min and can be adjusted with
valve DGR 1 (optional), depending on the application. When flow
is
too low a warning then an alarm signal is generated by
flowmeter
DGF to the PLC. Status of the pump depends on the
alarm function
set by user (factory setting : None, pump continues
running with
an alarm). Dilution improves the screws functioning,
especially
when sucking corrosive gases.
Optional functions/ Use of available
accessories
A temperature sensor mounted on the cylinder, measures the
temperature inside the cylinder.
A silencer or sound absorber (accessory) at the exhaust reduces the
noise
of the pump and collects any condensate.
A leak-protection non-return valve (optional) at the exhaust traps the
condensate in the pump when the pump is switched off.
The LCD controller processes the data of the sensors (see chapter
“Communication with the equipment”) as follows:
–
discharge pressure
–
temperature in the cylinder
–
current
–
cooling water flow rate
On/ Off button
The vacuum pump is delivered with on/ off button.
Versions
Further vacuum pump descriptions state the nominal displacement and
the design level.
Example: BC 0101 G
BC = standard version
0101 = 100 m
3
/h
G = Design
Safety
Intended use
DEFINITION
: To rule out any misunderstanding, the term “handling”
of the vacuum pump covers transport, storage, installation and
operation of the pump as well as effects on operating states and
troubleshooting on the vacuum pump.
The vacuum pump is intended for industrial use. It may only be
operated by qualified personnel.
The different application possibilities and limit values for operation
described in “Product description” and “Installation requirements”
must be observed by the manufacturer of the system into which the
vacuum pump is to be integrated and by users.
The need for personal safety regulations depends in principle on the
type of use. The operator must provide the users with the necessary
means and must inform his personnel about the dangers emanating
from the processed product.
The operator of the vacuum pump must observe the safety regulations
and must train and instruct his personnel accordingly.
Local regulations regarding the motors and electric control elements
must be observed when installing the pump in potentially explosive
environments.
The maintenance instructions must be followed and observed.
These installation and maintenance instructions must be read and
understood before the vacuum pump is used. If you have any doubts,
contact your Busch representative.
Safety information
The vacuum pump is designed and manufactured in compliance with
the latest technical standards and safety regulations. Nevertheless an
element of residual risk remains.
Various safety instructions are to be found in this handbook and on the
pump. These instructions must be followed. You can recognise these
instructions by the signal words DANGER, WARNING and CAUTION,
which are defined as follows:
DANGER
Disregard of this safety note will always lead to accidents with po-
tentially fatal injuries and serious damages.
WARNING
Disregard of this safety note may lead to accidents with potentially
fatal injuries and serious damages.
CAUTION
Disregard of this safety note will always lead to accidents with minor
injuries and damages to property.
Noise emission
Refer to the table “Technical data” for the permissible noise level in
free field conditions according to EN ISO 2151.
CAUTION
The intensity of the noise of the vacuum pump is higher within a
certain area of the pump.
Risk of hearing damage.
Users must wear ear protection when spending a longer period of
time in the vicinity of a non-insulated vacuum pump.
BC 0101 G
Safety
0870704904 (En)
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