7
6.2 Components of the pressure-boosting system
The complete system is made up of various main
components. The scope of delivery includes sepa-
rate installation and operating instructions for the
relevant operating parts/components (see also
the installation plan provided Fig 1).
Mechanical and hydraulic system components
The compact unit is installed on a
base frame (3)
with vibration absorbers (14)
. It consists of a
group of one, two or three horizontal c
entrifugal
pump(s) (1) with three-phase current motor (1),
which are combined by means of an
inlet pipe (4)
and a
pressure pipe (5)
(connection pipes in case
of 2 or 3 pumps) to form a complete system. Each
pump is fitted with a
(6) shut-off valve
on the in-
take side, a (
7) shut-off valve
on the pressure side
and a
non-return valve (8)
on the pressure side.
A kit with isolation valves is fitted on the pressure
pipe, which contains a
pressure sensor (12)
and
pressure gauge (11)
(Fig 1b).
All systems include an
8-litre diaphragm pressure
vessel (9) with a throughflow fitting (15) that can
be shut off
in the scope of delivery which is to be
fitted to the
pressure pipe (5)
(Fig 1b).
Low-water
cut-out switchgear (10) kit
(Fig 1c) is fitted to
the inlet pipe. The
control device (2)
is mounted
to
mounting brackets (13)
on the
base frame (3)
and ready wired to the electrical components of
the system. The present installation and operating
instructions contain only a general description of
the complete system.
High-pressure multistage centrifugal pump(s)
(1):
Different types of multistage horizontal centrifu-
gal pumps are installed in the pressure-boosting
system depending on the application and the per-
formance parameters required. Their number can
vary from 1 to 3 pumps. The attached installation
and operating instructions provide information on
the pumps
Control device (2)
(Fig 1)
:
The SC series control device is used to control and
regulate the SCe-Smart pressure boosting
system. The size and components of the control
device may vary depending on the design and per-
formance parameters of the pumps. The attached
installation and operating instructions, and the
corresponding wiring diagram provide information
on the control device installed in this pressure
boosting system.
Diaphragm pressure vessel kit
(Fig 1b)
:
•Diaphragm pressure vessel (9) with flow-through
fixture (15) that can be shut off
Pressure transmitter kit on the pressure side
•Pressure gauge
•Pressure sensor
•Electrical connection, pressure sensor
•Draining/venting
•Stop valve
6.3 Function of the pressure-boosting system
Wilo pressure-boosting systems in the ISAR
MODH1 series are standard-equipped with non
self-priming multistage horizontal centrifugal
pumps, with built-in frequency converter to the
control panel. These are supplied with water via the
inlet pipe.
The pump(s) increase(s) the pressure and pumps
the water to the consumer via the pressure pipe. To
do this, they are switched on and off and con-
trolled according to the pressure. The pressure
sensor continuously measures the actual value
of the pressure, which is converted into a current
signal and transmitted to the control device.
Depending on the requirement and the type of
control, the control device switches the pumps on
or switches them off. The speed of one or more of
the pumps is changed until the control parameter
settings are achieved (a more precise description of
the control mode and the control process is given
in the installation and operating instructions for
the control device). The total delivery volume of
the system is distributed over several pumps. This
has the big advantage that the system output is
adapted very precisely to the actual demand and
the pumps are operated in the most favourable
performance range in each case. This design de-
livers a high level of efficiency and an economical
energy consumption for the system.
The first pump that starts up is called the baseload
pump. The remaining pumps needed to reach
the system operating point are called peak-load
pump(s). To ensure that all the pumps are used
equally, the control unit cycles the pumps con-
tinuously, i.e. the order of switching on and the
allocation of the base load/peak load or
standby pump functions change regularly. The
diaphragm pressure vessel (total content approx.
8 litres) performs a certain buffering function on
the pressure sensor and prevents oscillation of the
control system when switching the system on and
off. It also guarantees low water extraction (e.g.
for very small leaks) from the storage volume at
hand without switching on the base-load pump.
This reduces the switching frequency of the pumps
and stabilises the operating status of the pressure
boosting system.
CAUTION! Risk of damage!
To protect the mechanical seal or slide bearing,
do not allow the pumps to run dry. If the pumps
run dry they may develop leaks
.
For connection to a break tank, a level-dependent
pressure switch is provided and installed on the
inlet pipe as a dry-running protection device.
WARNING! Health hazard!
Only materials that have no adverse effects on
the quality of the water may be used for drinking
water systems!
Summary of Contents for ISAR MODH1 Series
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