GRUNDFOS WaterPRO JUNE 2009
The new wave in water utility
Product Focus > Meet the New SL
Feature Article > Dedicated Controls for Network Pumping Stations
Tech Talk > Wastewater Pumps with Frequency Converters
International Project Reference > Controlling Vast Water Volumes at Dubai Drydocks
Local Project Reference > Grundfos Innovative Solutions Saves PBAPP Money and Space at Sg Dua WTP
MEET THE NEW SL!
Long-lasting, service-friendly submersible wastewater pumps
“The newly extended SL range
is industrial design at its best.
Created to optimise performance
in your system, these pumps
minimise risk factors, reduce
and last longer.
Like any Grundfos product, SL pumps are remarkably
durable. They employ innovative features-several of them
unique to Grundfos-to minimise known risk factors. The
SL pumps also let you plan service visits for maximum
efficiency-and keep those service visits shorter.
The SL (pumps) work with your system. They give you the choice-of impeller, of sensors, of speed control, etc.-that you need
for ideal pump set-up. And we can give you design advice to make the most of it.
SL PUMP PERFORMANCE
SuperVortex impeller pumps
(SLV) are available for free
passage of solids up to 100
mm. Ideal for liquids with
high content of solids, fibres,
or gassy sludge.
Channel impeller pumps (SL1)
are available for free passage
of solids up to 100 mm. Ideal
for large flows of raw sewage.
5 10 15 20 30 40 50 100
20 40 60 80 100 200 Q[m 3 /h]
The entire range is available in explosion-proof versions. All DP and EF models and SL1 and SLV models with motors up to 1,5kW are provided with a II 2 G Ex c d IIB T4 explosionprotection
classification according to EN60079-0:2006 and EN60079-1:2007. All other SL1 and SLV models are provided with an II 2 G Ex c d IIB T4, T3, and for sensor versions,
an II 2 G c d mb IIB T4, T3 classification according to EN60079-1:2007, EN13463-5:2003, and EN60079-18:2004.
SL PUMP FEATURES
-and what they do for you
A two-component sealant
filling the plug prevents
moisture from entering the
motor via the cable core
Short rotor shaft
vibrations to protect
shaft seals and bearings
Double mechanical shaft seal
Primary and secondary seals are
combines into a single cartridge
to reduce maintenance time
SL models have motors
based on Eff1 components,
improving motor efficiency
and prolonging pump life
Many sensor options
Larger SL models
available with integrated
water in the intermediate
oil chamber, and motor
Easy access for pump
180˚ rotation of the
Dedicated Controls for
network pumping stations
For sewage networks
The Dedicated Controls are envisaged for use in
sewage pumping stations combining one or two
pumps and a mixer. This makes them obvious choices
for mains systems, commercial buildings, and similar
The Dedicated Controls system builds on Grundfos’
experience with their own series of level controllers
for pump monitoring and control – specifically the
acclaimed LC series and Modular Controls system
– but greatly expands the functionalities available.
The Dedicated Controls range is developed for
those who want something extra. For example, the
monitoring functions have been expanded to include
pumped volume and overflow durations – and the
Grundfos, one of the
world’s leading pump
and manufacturers, now
launches its Dedicated
– a sophisticated
monitoring and control
specifically for network
communication options have been expanded, too:
the Dedicated Controls system offers SCADA and BMS
communication using GSM/GPRS. Among other things,
this means that the options now also include a text
messaging service which allows users to control and
receive information from their pumping station on
their mobile phones.
Large graphic display
The large graphic display is another new feature. It was
created with the help of leading experts on interface
design for easy read-outs and easy operation. The
display shows a visualisation of the pumping station,
making it easy to find the information required – and
to adjust any settings. A Wizard function takes users
through the different functions step by step – in the
language of their choice.
Supported by PC tool
The Dedicated Controls system can be used with
Grundfos’ own PC tool created for on site service as well
as remote preparation, verification, and management.
The PC tool was also created for maximum userfriendliness.
It can be used for set-up and commisioning
of the pumping station – and to create backups of
your settings and parameters. You can even send your
settings via email to make commisioning simplier.
And once the station is up and running, the PC Tool
offers a full set of functionalities – on site or from a
Part of a system approach
The Dedicated Controls system reflects how Grundfos
has moved from being primarily a pump manufacturer
to become a wide-ranging developer of pumping
systems and environmental technology.
Grundfos has always designed the products with a focus
on improving system performance. The main difference
is that over the last decade, Grundfos has gradually
started developing more and more system components
ourselves. Those components include everything a
client could need for a pumping station: “Grundfos
offers prefabricated and customised pumping station
on any scale, including all fitting, valves, and controls.
And pumps, of course. Everything fits together perfectly,
and the Dedicated Controls solution adds extra
functionalities for those who want them.”
Dedicated Controls at a glance
• Expands the scope of the Grundfos controls range
• Control one or two pumps
• Supplied as modules or as part of complete
• For motors up to 11 kW (direct on line) or 30 kW
(star/delta) or softstarter
• Analogue input 4+20 mA (pressure/
ultrasonic transmitters) and/or up to five
• Also control mixer/flush valve
• User-friendly display interface – includes
• Connect to all standard PLCs, SCADA, and
• Full data logs
• Customise your alarm scedule
• Text messaging – control pumps and receive
information via SMS
• Early warning
• Compatible with the Grundfos Remote
Dedicated Controls were created specifically for network
The Dedicated Controls system is available now.
OPERATED BY MEANS OF
In general, frequency converters
are used to change the duty point
of a pump. In wastewater
applications, this means that they
are used to regulate the flow in
the system. Converting the initial
frequency from 50 Hz to another,
lower value will have consequences
for the flow, the head and the power
intake of the pump; consequences
that can be calculated by means
of these equations:
Q 1 = Q 0 x
H 1 = H 0 x
P 1 = P 0 x
f1 f0 f1 ( f) 0
f1 ( f) 0
NPSH 1 REQ = NPSH 0 REQ x
f1 ( f) 0
Consequences for pump cooling
From the power equation we learn
that the introduction of frequency
converters would not create any cooling
issues since the power intake decreases
to the third power.
An initial shaft power of P 0 = 30 kW
at f 0 = 50 Hz will be reduced to
P 1 = 15.36 kW at f 1 = 40 Hz. In the case
of pumps without cooling jackets, the
outer cooling surface and the material
mass inside the pump itself will easily
dissipate the heat.
However, when pumps are equipped
with a cooling jacket – inside which
the cooling water is provided by the
POSSIBLE JAMMING OF THE PUMP
When the motor frequency is lowered, the rotation speed
of the impeller will slow down and affect the velocities in the
impeller and the pump housing. Depending on the specific
hydraulic design of the pump in question, critical velocities
may be reached, causing impurities to settle in the pump
housing and in the impeller itself. Clogged impellers become
unbalanced, causing vibrations in the pump. The risk of
mechanical damage, wear, and excessive leakage from the
mechanical seals will shorten the lifetime of the pump.
When the flow is reduced due to lower speed, the velocity
in the pipe is also reduced. This presents a risk of particles
and fat settling. Therefore we recommend minimum
velocities for wastewater: 1 m/s in vertical pipes and 0.7 m/s
in horizontal pipes.
When sedimentation in the pipes occurs, the inner diameter
of the pressure pipe is reduced and the pump will operate at
a higher pressure (A1 to A2). The reduced inner diameter of
the pipes means that the flow will be reduced even further
(Q1 to Q2), which has the consequence of increasing velocity
(v1 to v2). The result is higher friction loss in the system.
pumped liquid moved by the impeller
– the heat transfer of the motor could
be a concern.
Slowing down the rotation speed of
the impeller decreases the flow in the
jacket. This reduced flow decreases
the velocity around the cooling jacket.
Bigger solids, fats, or long fibers in the
wastewater are at risk of settling when
the velocity reaches a critically low
value. After a while the cooling jacket
will become clogged, preventing any
water circulation at all.
When this happens, the accumulated
sludge and remaining water in the
cooling jacket creates an insulating
v > v1
layer around the stator. Even at lower
frequencies, this could overheat the
motor. This is not a problem with
Grundfos pumps. Thanks to Grundfos’
integrated cutting system, fibers and
large solids are cut into small pieces
before entering the jacket. These small
particles remain suspended, preventing
them from clogging up the jacket.
Q Q1 Q
Depending on the stagnant time and running hours
at lower speed, such clogging in the pump and pipes can
permanently disturb the functionality of the complete
The clogging phenomenon caused by reduced wastewater
velocities has an adverse impact on the operation of the
pump and the system.
Therefore, we do not recommend the use of frequency
converters for unscreened sewage unless velocities are kept
under control in every section of the entire pipe system.
Regularly speeding up the pumps to their full speed will
clean the pump hydraulics and the pipes. These cleaning
sequences can be pre-programmed in the controller. The
best interval between such cleaning sequences depends
entirely on the consistency of the sludge and can only be
determined by experience. However, we recommend that
you set the pumps to perform a cleaning sequence once
Flow regulation can be safely and easily obtained by
increasing the number of pumps. This configuration also
increases the reliability of the system.
Q1 Q Q Q Q Q Q
Q total=n x Q1
If you decide to work with frequency converters, all velocities
in the different parts of the system must be checked.
We recommend that you involve the pump manufacturer
in the design process in order to be informed about the
hydraulic limits of the pumps and the most appropriate
WATER VOLUMES AT
Customer: Dubai Drydocks
Dubai, United Arab Emirates: The Dubai Drydocks have moved on from their early beginnings in 1971 to become one of the
leading ship repair yards in the world – and the premier yard between Europe and the Far East.
Since beginning operation in earnest in 1983, the shipyard has repaired over 5,000 vessels of all types and sizes. Many of
those vessels are ULCCs and VLCCs, representing a large proportion of world’s tanker fleet. The yard employs over 5000 skilled
employees, a workforce which is supplemented by up to 1,500 workers from local subcontractors when required.
In 2005, the Dubai Drydocks decided to strengthen their position within the markets for marine ship repairs, conversions,
and shipbuilding. This was to be done by upgrading the yard to include launching facilities for new-built ships
as well as for large fabricated steel structures and offshore modules. The expansion would allow the Dubai
Drydocks to build vessels and/or hull sections of 120x60m. To bring about the upgrade, the Drydocks launched
the so-called Safina project, a USD 60 million undertaking with the objective of creating a new building facility. The new
complex was to include a sea-water pumping system for an innovative hydrolift to handle ship launches.
10 InternationalProject Reference
The hydrolift explained
The hydrolift is used to safely transfer large sections of hull
from land to sea, and then into the drydock for final assembly.
First, the hull sections are transferred via rails from the
manufacturing area onto a platform within a walled basin.
A gate located across the transfer route enables the basin
to be pumped full of water, causing the hull section to float.
The hull section is then manoeuvred into a deeper part of the
basin from where it can be taken out to sea after the water
level is lowered and the main seaward gate is opened.
The project involved the construction of diaphragm quay
walls, impounding walls, a concrete transfer platform, massive
entrance abutments and two gates, including a floating steel
caisson weighing in excess of 1,400 tonnes.
The hydrolift system will enable the launching of hull sections
up to 120m x 60m. As an added benefit, the transfer process
can also be used in reverse with ships being recovered onto
the platform for general repairs.
Large-scale pumping requirements
The hydrolift required large-scale pumping capacities. The
tender materials specified four mixed-flow propeller pumps,
each with a nominal capacity of 2200 l/sec at a 10m head.
The pumps are installed in chambers on the seaward face
of new dock gate, while the installation was designed with
the discharge pipe located below the sea level. The overall
dimensions of the floatout basin are 131 x 66m, bringing the
total volume of water to be pumped up to 122,050 m 3 . The
installation was designed with the discharge pipe located
below the sea level.
The Grundfos Solution
When it was time to select the specific pumps used to fill
the hydrolift’s basins, the consultant, Royal Haskoning U.K.
Ltd, invited bids from major companies such as Grundfos,
Flygt, KSB, ABS, and WEIR. Based on a thorough assessment of
the task at hand, Grundfos recommend a mixed-flow pump
– specifically the 1000KWM300 12T4, a KWM pump with a
nominal power rating of 300 kW and a 425 RPM motor. Like all
K-range pumps, these pumps would be adapted to perfectly
match the intended application. In this case, highlights include
an epoxy coating and zinc anodes for additional corrosion
protection – and the inclusion of all monitoring devices.
Grundfos package proved most attractive
While most bidders were rejected on technical grounds, a
non-Grundfos European manufacturer seemed most likely
to get the order, having been involved in the project from an
early stage. However, in the end the customer was convinced
that the Grundfos package offered convincing arguments.
11 InternationalProject Reference
Grundfos input counteracted cavitation
A key point behind the final decision to use K pumps
was the fact that Grundfos offered more than just the
product. For example, the Grundfos team took at good
look at the tender specification and then recommended
what they would change. With the original design, the
pump would have been subjected to cavitation caused
by a siphoning effect created by the fact that the
discharge end of the pipe was located below sea level.
The Grundfos engineers suggested some modifications
to the discharge pipe; changes which were accepted
by the consultant. Grundfos also provided detailed
information on how to create the best possible cable
and chain supports system.
Completed in 2006, new hydrolift system is now
working perfectly, with vast water volumes controlled
reliably by the KWM pumps. Distinctive features such
as the pumps’ low RPM and excellent NPSH help ensure
efficient operation as well, adding more benefits
to a project in which Grundfos is very proud to have
Read more about the Grundfos pump range at
1 LocalProject Reference
SOLUTIONS SAVES PBAPP
MONEY AND SPACE AT
SG DUA WTP
Sungai Dua Water Treatment Plant is currently the largest WTP in Penang. It is able to produce 770 million litres per day (MLD).
500 MLD of the production is distributed to Mainland (Seberang Perai) and the balance of 270 MLD is distributed to Penang
Island. Sungai Dua WTP is taking charged by Perbadanan Bekalan Air Pulau Pinang (PBAPP).
There are 18 nos. of filter beds at Sungai Dua WTP and they require a total of 0.57
million litres water and 21m head for every backwash process, 7 times per day. If
PBAPP is going to tap from the treated water line, then the pressure of distribution
line to the customer would be greatly affected. On top of that, a lot of post
chemicals (Chlorine, Hydrated Lime and Sodium Silico Fluoride) would be wasted if
the treated water is used for filter backwashing process.
In order to overcome these problems, they have decided to use water from the
storage tank after the filtration process instead of using the treated water. To
serve that purpose, PBAPP needs 2 nos. of split casing pumps to be installed to the
existing system. But then the space constraint would be another issue that they
need to solve.
PBAPP has found a solution with Grundfos when we recommended our PACO
vertical split casing pump to them. The KPV model is a vertical split casing pump
which requires very minimal ground space. For PBAPP, this was the first ever vertical
split casing pump being installed. With the right pump installed, PBAPP has saved
averagely RM100,000 per annum on the operation cost that consume chemicals
and also energy cost on the treated water. On top of that, the ROI was just 6 years
and the pumps are running fine until now.
PBAPP commented that they are very satisfied with the pump efficiency and the
robust design of the motor stool. It helps to reduce the upthrust load and the
alignment issue during operation. They are very pleased as well with the minimum
maintenance throughout the operation period.
GRUNDFOS PUMPS SDN BHD ( 0 -A)
7, Jalan Peguam U1/25
Glenmarie Industrial Park
40150 Shah Alam
Tel : +603 5569 2922
Fax : +603 5569 2866
Email : firstname.lastname@example.org
Cert No: KLR0 0 0
Northen & East Coast
10, Ground Floor,
Jalan Todak 4,
13700 Seberang Jaya,
Tel : +604 818 3779
Fax : +604 818 3848
Lot 8, Lorong Industri Warisan 1,
Taman Industri Warisan Indah,
Mile 7, Old Tuaran Road,
88450 Inaman, Kota Kinabalu,
Tel : +6088 380 663/+6088 383 663
Fax : +6088 383 621
Perbadanan Bekalan Air Pulau Pinang