Function; Main Components - Nederman RBU 1300 Manuel De L'utilisateur

RBU
Material description
Material recycling
Min. operational frequency, Hz
Max. operational frequency,
Hz
Max. rate of frequency
change, Hz/s
*
Motor weight included.
** Never change the setting of the safety regulator.
3.2 Function
The RBU (Roots Blower Unit) is a series of vacuum
units fitted with a 3-lobe root pump vacuum source.
See Section 3.1 Technical data
formation. The motor is a 3-phase asynchronous mo-
tor. See the RBU unit machine tag for details regard-
ing voltage, current, motor power, and frequency.
The root pump's power consumption increases with
increasing vacuum and decreasing airflow (pump
characteristics).
For Y/D started models it is necessary to minimise the
power requirement during Y/D-starting. This is done
by opening a solenoid valve for free admittance of air
to the pump when the motor runs in Y-mode.
All RBU units are fitted with a combined start-up and
vacuum limiting valve. This valve is controlled by low
friction compressed air cylinder, a solenoid valve
and two regulators. The valve opens if the vacuum
reaches the working vacuum level or the safety vacu-
um level. When the valve opens incoming air lowers
the vacuum. The opening of the valve will depend on
(1) the vacuum in pump and (2) the force of the low
friction compressed air cylinder pulling the valve in
the opposite direction. The force in the compressed
air cylinder rises when air pressure fed to the com-
pressed air cylinders raises. In this way, the regulat-
ors adjust the vacuum by affecting the valve disc po-
sition which in turn changes the air pressure to the
compressed air cylinder.
The working vacuum level is adjusted using the regu-
lator closest to the cylinder, see
level is set before delivery and no further adjustment
is normally required. See
regarding regulator adjustment.
CAUTION! Risk of equipment damage
The safety valve regulator must never be ad-
justed, Figure 1 item 16. Incorrect setting of
the safety valve regulator damages the pump
and the warranty will be rendered invalid.
1300 1600
Powder-coated steel, copper, stone wool insulation
Approximately 95–97% of the weight
regarding airflow in-
Figure 1 item 15. The
Section 8.11 Vacuum level
RBU
1600E 2100
N/A
N/A
N/A
At the universal valve, entrance is a rubber disc back-
flush valve. The valve is used when two or more RBU
units are hooked up in parallel and prevent units not
yet started from running backwards.
A rubber disc overpressure valve is placed on the uni-
versal valve side, see
sure valve opens and lets air out if the pump runs in
the wrong direction during the initial start-up.
After the universal valve, the air passes through the
inlet silencer to the roots pump. Underneath the pump
is a rigid discharge silencer. An additional spiro bend
silencer leads the air out from the unit.
On Y/D started models a thermal fuse is placed in the
lower flange of the pump, see
fuse trips at ≈ 140 °C (≈ 284 °F) with an indication to
the start- and control unit which stops the unit. See
Section 8.7 Thermal fuse
On models intended for use with a variable frequency
drive, the pump temperature is monitored with a
PT1000 temperature sensor. The pump must be
stopped if the pump temperature reaches 140.
Models intended for use with a variable frequency
drive are also fitted with PT1000 temperature
sensors for monitoring the motor's surface temper-
ature as well as the temperature of the cooling air in-
take.
4 Main components
Figure 1 shows the main components of the RBU unit.
These are as follows:
1 Inlet silencer.
2 Outlet spiro silencer.
3 Noise-absorbing enclosure.
4 Spiro silencer with a 90° bend.
5 Motor.
6 Transmission.
7 Belt guard.
8 Discharge silencer.
2100E 2600 2600
FC
20
60
1
Figure 1 item 18. The overpres-
Figure 1 item 10a. This
for more information.
EN
15