28th Edition Mechanical Engineers' Notebook

Armstrong Fluid Technology - Case Study - 97

Blackburn Meadows, Sheffield

An important district heating scheme in Sheffield, which generates
heat and energy from waste wood, has come to fruition with the
help of an integrated packaged pump solution from Armstrong
Fluid Technology.

The pump solution incorporates six large Armstrong 4300 Series The specification of integrated pump solutions from Armstrong Fluid
variable speed pumps with built-in inverters, integrated with Technology also had significant advantages in that it harnessed the
Armstrong’s IPS 4000 pump controller, which optimises operation of all benefits of off-site manufacture. Instead of being constructed in the
6 pumps to minimise energy consumption. traditional way (with components being delivered individually and
assembled on-site) the integrated pump solution was assembled,
When planning the pump house for the district heating scheme, RK integrated and tested off-site, at Armstrong’s purpose designed factory
District Heating Limited had several priorities. The pumping in Halesowen.
requirements for the scheme are complex and involved handling of
water at high maximum temperatures (up to around 115°C). The plant The completed pump solution was supplied to site ready-assemble just
needs to offer outstanding levels of energy efficiency across a wide requiring final connection. Off-site manufacture ensured that all
range of operating conditions, as the district heating scheme is being components for the pump solutions were connected and integrated
expanded incrementally over time. exactly as required, maximising control over the final quality of the
systems and ruling out the risk of errors.
In addition, the demanding timescales for the project meant that the
equipment needed to be installed within shorter than average lead times. Using this approach, the timescales for delivery of the project were also
reduced significantly, with assembly of the packaged plant able to
At the heart of the system are six Armstrong 4300 DE variable speed progress concurrently with on-site construction, unaffected by adverse
pumps integrated with Armstrong’s IPS 4000 pump controller. The weather or other potential delays.
variable speed pumps incorporate on-board inverters which enable
them to respond instantaneously and automatically to changing “I have had favourable experience of Armstrong’s work in the past and
requirements, adjusting their motor speeds and drawing only the power had no hesitation in specifying them for this project.”
required to meet the load.
David Forrest
As they are Armstrong Design Envelope models, they also provide
energy efficient operation across a wider operational range than other Project Manager
pumps, providing flexibility to adapt in the future without the need for RK District Heating
replacement or system over-sizing.

The pumps are controlled by the Armstrong IPS 4000 which
calculates how best to meet demand and automatically manages
pump operation accordingly.

The IPS 4000’s advanced control technology ensures that pumps are
operated at their most efficient points at all times and are phased in and
out in the best possible configurations to deliver the required capacity.
By treating the system holistically, and balancing supply across all 6
pumps, the IPS 4000 can achieve levels of efficiency that exceed those
made possible by less sophisticated capacity-based control
methodologies.

As the biomass-based district heating scheme has a particularly wide
range of operating scenarios, the advanced control made possible by
the IPS 4000 ensures that energy efficiency is optimised whatever
variations may occur.

In the future, as additional plantrooms across Sheffield are integrated
with the district heating scheme, the IPS 4000 will ensure that the
pumps adapt to accommodate the changing requirements whilst still
maintaining optimum energy efficiency.

The additional flexibility and sophisticated control provided by the
Armstrong pumps and IPS 4000 controller means that the energy
wastage associated with over-sizing of systems is avoided.

Armstrong Fluid Technology Ltd Tel : +44 (0) 8444 145 145

Wolverton Street @ArmstrongFT

Manchester armstrong-fluid-technology

Lancashire [email protected]

M11 2ET www.armstrongfluidtechnology.com

98 - Vacuum Drainage Technology

Applications & Advantages Health & Hygiene

The building sector has been slow to move to vacuum drainage Unlike conventional toilets which permit bacteria and odours to enter the
technology, but with the confines placed on new projects such as small atmosphere, the Evac toilet takes out up to 100 litres of air on each flush,
conduit and service ducts and the growing awareness of the need to limit removing viruses, bacteria and odours from the bowl and into the system.
water consumption, the system is now finding a place in the building This cycle of air will keep the toilet accommodation fresh, enhancing
sector. As the system is capable of lifting sewage from appliances such hygiene and personal comfort within washrooms.
as WCs and running in voids above these appliances, the system offers As the complete pipework system is held under a vacuum, it is impossible
the designer greater flexibility and freedom to position appliances where for infestations or rats to live and breed in the drainage. Every Evac
most suitable for the building. system, when installed, is a closed loop. This is particularly important
The Evac Vacuum Toilet System could not be simpler. Instead of relying where an organisation requires waste to be contained if contamination
on traditional solutions which use the principle of gravity to remove waste is considered high risk e.g. hospitals, research facilities and prisons.
and are heavily reliant on the location of service cores and outgoing sewer
connections, the Evac system creates a powerful vacuum to flush the Water Savings & Energy Consumption
toilet which works like this...
Once the flush button is pushed, a pneumatic signal is sent to the control Water and energy consumption will be dependent on the size, type and
mechanism which opens the discharge valve by allowing a vacuum from use of the building and its vacuum drainage system. Evac systems are
the pipework system to enter the discharge valve diaphragm, thus very environmentally friendly – one of the biggest savings on natural
connecting the bowl to the vacuum system. Air at atmospheric pressure resources is the dramatic reduction in water consumption.
then forces sewage through the discharge valve and into the piping. A conventional toilet consumes between 4.5 and 6 litres of water every
The water valve is opened, and pressurised rinse water cleans the bowl time it is flushed. The Evac toilet typically uses just over one litre of water
simultaneously. The whole operation is performed using just vacuum – per flush – 1/6 of that used by a conventional toilet.
NO electrical connections Using less water will bring significant cost savings as water rates rise and
are required. as Evac toilets have very low water consumption, the actual amount of
Evac toilets can be re- sewage produced is also reduced, helping to ease the burden on
flushed more than 4 times overloaded public sewage plants. Vacuum retention tanks can also be
faster than conventional discharged during off-peak periods.
gravity toilets; on average,
an Evac toilet will take 5 Total Water Cycle
seconds to complete a
flush cycle as there is no When considering a vacuum toilet system and comparing it against a
toilet cistern to refill. gravity system, you must compare the complete water cycle. There is a
Evac systems also reduce saving in both the cost and power by bringing less water into your building.
leakage problems. If that water must be stored in the building, then the use of vacuum toilets
The problem of leakage due to pipe fracture is reduced – as a vacuum will reduce the size of any storage tanks, freeing up valuable floor space
exits throughout the system, any leakage is directed inward rather than or reducing excavations for underground tanks. If the tanks are to be
outward. sited at the top of the building, the structural requirements of the building
Whilst the Evac vacuum toilet is an integral part of the system, the system can also be reduced.
will also accept waste from all other gravity fixtures, including wash Once your water is in the building, you will have to move the water around
basins, baths and showers using a Vacuum Interface Valve which is it. The larger the building, the more power will be consumed in this
similar in operation to the Evac vacuum toilet. The manually operated process, so the small amount of water that you must move, the less power
push button is replaced by an activator which is triggered when a static you will need to consume.
head has been built up in the grey water tank. After the water has been used to flush a toilet, it must be disposed of. In
The whole operation is automatic, and no electrical connections are large buildings with conventional gravity toilets, this can mean several
required. The valves allow standard bathroom fittings to be connected to sewage pumping stations located around the building to get the sewage
the vacuum drainage system in new build projects and eliminates the from the building into the main sewer. By consuming less water, the
need to replace existing fittings in a refurbishment project. Evac gives vacuum toilet system also produces less sewage.
the building designer complete freedom from the restrictions of gravity The flexibility of a vacuum drainage system means that all the sewage
fed plumbing. Bathrooms and toilets do not need to be tied into a services from the building can be brought back to one location in the building. If
core but can be located where best suits the design. the black water is to be treated in-house then the lower level of sewage
will impact on the size and type of sewage treatment plant required,
Increased Design Flexibility saving costs, space and energy.

Evac toilets can be installed just about anywhere in a building. Pipes are Case Study - Travelodge Welwyn Garden City
small bore (normally 50-75mm) and can be routed around and even over
obstructions. As they are not reliant on the locations of service cores and When Travelodge discovered a vacant office in the centre of town, it was
do not need vent stacks, design flexibility is maximised. Anywhere you soon determined that it would prove an excellent venue for their
can imagine an Evac toilet system in the design of your new build or ever-increasing portfolio of inner-city hotel accommodation.
refurbishment project, it can be achieved. Not only was the building in the centre of town, but also positioned
Evac systems are not dependent on gravity; therefore, waste pipes do immediately next to a railway station which is just 30 minutes into London
not need to slope downwards which means that Evac toilets can flush Kings Cross. However, this building proved challenging as the vacant
along the level – even upwards when downward flushing is inconvenient. office space sat directly above multiple retail outlets.
This opens a wealth of design opportunities, especially in refurbishment, Converting this space into a hotel would have resulted in sewage pipes
extensions and retrofit projects. from the rooms above running directly into the retail areas below.
Evac systems give vertical lift of up to 5m, giving unparalleled flexibility The design team then looked at the prospect of a vacuum drainage
in installation. Toilet cubicles, urinals, showers and hand basins can be system. The complete design team were taken to an existing Evac
positioned wherever you want, regardless of conventional soil stack vacuum drainage project to be able to not only see and understand a
practice. As there is no need to be adjacent to a central soil stack, the previously installed system but talk with that buildings facilities team and
location of toilet accommodation can vary from floor to floor. gain confidence in the integrity of the system.
In speculative buildings, a prospective tenant will often wish to plan the Eurovac were able to work with the architect and consultants and assist
space available in a building to suit its business operation. The Evac with the design where 55 of the rooms were fitted with the Evac vacuum
system gives you this extra capability. Final decisions on the floor plan drainage system thus allowing the small bore pipes to run at high level
can be delayed leaving maximum room to manoeuvre and giving the in the communal corridors before dropping down at a convenient point
client maximum flexibility to plan space. to enter the main vacuum drainage plant.
It is hoped that Travelodge will consider the Evac system for future
projects.

European Vacuum Drainage Systems Tel : 01634 684 779

Unit 35 Lordswood Industrial Estate Fax : 01634 661 510

Gleamingwood Drive @EVDSltd

Chatham Email : [email protected]

Kent ME5 8RZ Website : www.evds.org.uk



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