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Telemetry |
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Telemetry Applications
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News:
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| Sewage
Pumping |
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Sewage
Pumping Stations are used externally to Sewage Treatment works to assist
gravity in getting the raw sewage from its places of origin to the works for
treatment. Sewage can only travel down hill so far before it has to be lifted
back to a higher level to start its down hill run again. Sewage Pumping
Stations exis ts all around the sewage network for this purpose and have stand
alone controls which keep these unmanned stations operational or warn engineers
by telemetry at a central remote computer when something has gone
wrong.
The incoming flow enters into one or more wet wells (dependent
on the size of the district) and is pumped from these on its way to the next
station but if the pumps fail the wells will overflow to the outside world with
dire consequences, therefore level and flow monitoring, along with the
machinery status is essential. There are also many more functions that often
take place and are continually monitored.
 Many individual pumping stations (outstations) report to one
Masterstation. Apart from keeping the operating engineer aware of the status of
all of the Pumping Stations under his control, the Master Station allows
commands to be sent to the Outstations to start or stop pumps, along with a
variety of other functions without the need to visit the remote site.
To carry sewage from where it is produced to where it will be treated and
disposed of, sewers are laid with a gradual downward slope so that the sewage
flows under the influence of gravity. Pumping stations of the type that are
illustrated within Figs. 1 and 2 are used to achieve this purpose and are a
strong market for DL and DTS products.
Some sewers carry only used water
discharged from houses, shops, offices and factories, the majority however,
carry rainwater run-off from roofs, roads and paved areas that do not allow the
rainwater to soak into the sub-soil and ultimately the aquifer, these sewers
are known as 'combined' sewers.
 In general, all new housing developments will have a pumping
station similar to that within Fig. 1 located on or adjacent to the developed
site to connect to the nearest neighbouring sewer.
Rising mains (or
pumped mains) are used to move sewage to a higher level by the use of a pump or
pumps. The quantity of pumps generally ranges from one to three dependent on
the flow through the system and the time of day. The requirement is determined
by the level as it rises and falls within the 'wet' well in the station type
illustrated within Fig. 2.
Apart from sensing and controlling the
pumps dependent on the wet well levels the telemetry outstation located at the
site would also sense alarm levels within the wet well if for any reason the
level were to continue to rise either due to pump failure or where the existing
pumps were unable to cope with an inlet flow that was beyond their design
capability, usually during severe storm conditions.
Other alarms are
also provided to warn of such possibilities as three phase failure, phase
shifting, loss of single phase supply used for control power and intruder
alarms. Fig. 2 illustrates a typical pumping station that employs a 'dry' well
within which the pump is located, there is also a third type where submersible
pump or pumps are used, this is illustrated in Fig. 3. Fig. 3 Submersible
Pumping Station
In general the same control philosophy is employed
regardless of the style of pump that is used. To monitor the levels within the
wet wells the types of sensors that are employed are illustrated
 
The types of level sensing that
are illustrated within Figs. 4 and 5 are used within pumping stations and
throughout sewage treatment works where level measurement is required.
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