If
the pump appears to be the problem and you need help with your
investigations, please use the Contact Page to book an appointment for a
PSP engineer to visit. To obtain more information on the

PSP Pool
Owners Club, please visit the Members Page. The information on this page
will be added to the appropriate section for

members future searches.
Water is pushed through a bed of filter sand and removed through a set


of lateral tubes at the bottom.
Sand dunes are not only made of sand
but also of water. You don't have to dig very far to

see the moisture
in the sand. One of the unique features of sand is that it helps filter
water that passes through it. Go out

to the sand and have the students
dig into the sand and describe what they find. Talk about why they think
it is cool and wet.

Ask the students where they think the water came
from and where they think it goes. Doing Castles in the Sand prior to
this

activity helps students understand how sand and water work together
through a process called capillary action. Raw water flows down

wards
through the filter bed and as the suspended matter- which has usually
been treated by addition of a coagulant like alum-

is retained on the
sand surface and between the sand grains immediately below the surface.
There is steady rise in the loss of

head as the filter process continues
and the flow reduces once the Pressure sand filter drop across the
filter is excessive.
The Pressure sand filter is now taken out of
service and cleaning of the filter is effected by flow reversal. To
assist in

cleaning the bed, the backwash operation is often preceded by
air agitation through the under drain system. The process of air
scouring agitates the sand with a scrubbing action, which loosens the
intercepted particles. The filter is now ready to be put back

into
service. Picture Low Flow PSF (FRP Vessel) and High flow custom Vessel
(MS Vessel) Sand filter - Sand filters are used for

water purification.
There are three main types; All three methods are used extensively in
the water industry throughout the

world.
Also the isolating ball
valves could be partially turned off or blocked with debris, or even a
blocked filter

basket in the pump to a blocked pump chamber or impellor
inside the pump, or finally a restricted inlet to the multiport fitted
to the filter. Further investigation will be needed to find the reasons.
If the plantroom is below water level, make sure you can

isolate the
pool totally including any returns and that the ball valves are
installed in the correct direction. If the pump

appears to be the
problem and you need help with your investigations, please use the
Contact Page to book an appointment for a

PSP engineer to visit. To
obtain more information on the PSP Pool Owners Club, please visit the
Members Page. The information

on this page will be added to the
appropriate section for members future searches.

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