Silt & Mud Solutions
General Information
Silt and Mud present potential wear problems to most pumps and
valves. The presence of suspended matter in water may be caused
from constant agitation or may be the result of a temporary situation
such as a heavy rain. In most cases there will be a clear or clean
layer where the water will be of a higher quality. By pulling water
from this area you will usually find very little of the suspended
particulate. If these conditions exist a Dry Hydrant design should
be selected that will allow an intake to be located in this clean
or clear zone. In designing these installations one must first determine
the type of suspended matter, when is the suspended particulate
likely to be present and if a clean layer exists, where it's located.
If no clear area is ever present, it may be necessary to bury the
intake in a sand bed. The sand will then act as a filter, preventing
the suspended particulate from getting into the water supply. This
method can also be used to obtain water in areas of the country
where the water table is quite high and the soil is very sandy.
Florida and California are some of the areas where this type of
intake can be used.
In all cases where you have suspended particulate that is slowly
settling to the bottom, the strainer holes should always be installed
down. One should also take into account the age of a pond when making
a permanent placement of the strainer above the floor. For new ponds
install the bottom of the strainer at least three feet above the
floor of the pond. This will provide one foot for settlement, which
could occur over the next 5 years. Strainers being installed in
old established ponds should be installed about 2 feet above the
floor.
Warning: For new pond installations one should check frequently
for sand and mudslides caused from surface runoff. This can be a
huge problem if the watershed area is not properly seeded or landscaped
to prevent erosion. Often times one must relocate or dig out around
the strainer because of surface water runoff.
They are several ways of placing an intake into the clear zone.
- Supported vertically from the bottom (rigid installation).
- Suspended horizontally from the bottom (adjustable installation).
- Supported vertically from the top (rigid installation).
- Suspended horizontally from the top using flotation buoys.
- Buried intake in a sand bed.
Below are diagrams of these installations. You will note more than
one diagram may work for your situation. To select the proper diagram,
first make a list of your requirements. Second, match the requirements
to the particular design. Third, evaluate each selection from a
price and maintenance standpoint before deciding which solution
best fits your requirements.
1. Supported vertically from the bottom (rigid installation)
The design shown below uses three Barrel Strainers. These strainers
have holes 360 degrees radially around the pipe for a length of
20 inches. Low Level Bridge Strainers turned upside down also work
very well and limit the intake zone to an even shorter distance
of only a few inches. By using more than one strainer the suction
velocity is greatly diminished, thus reducing the chance of suspended
debris and weeds being pulled into the strainer.
In addition to providing multiple suction points, the cross arms
also act to support the weight of the piping in muddy bottoms and
provide good stabilization to the strainers. A "T" fitting
can be used if only two strainers are desired. The vertical placement
of the strainer will depend on the age of the pond and/or the location
of the clean zone. For new ponds allow at least a foot for sediment
that may be deposited prior to the pond becoming stable. This process
may take up to 5 years.
2. Suspended horizontally from the bottom (adjustable installation)
This design utilizes a short piece of flex hose and a floatation
buoy installed around the suction pipe. The buoyancy of the float
device will try to float the strainer, but is restrained by a SST
Cable anchored in concrete on the bottom of the water supply.
This design may be used in river areas where flooding, heavy debris
or other changing factors enter into the picture. The design also
provides a means of raising the strainer for inspection. This design
also can be used to prevent boating hazards.
The cable follows the contour of the bottom, and can be attached
to a simple boat winch on the bank. It may be wise to lock the winch
handle to prevent tampering.
3. Supported vertically from the top (rigid installation)
This design uses a supporting structure such as a bridge or pier
to maintain a given intake point below the surface. This design
is intended for water supplies where the level is fairly stable
year round. It does not provide any adjustment should the water
level change.
As noted before Barrel Strainers or Low Level Strainers work very
well in this application. Special large basket strainers can also
be designed for this use.
4. Suspended horizontally from the top using flotation buoys
This design uses a short section of flexible suction hose and a
standard boat-mooring buoy. The 3 ft. flex hose assembly comes complete
with; 6” Sched 40 PVC, Straight Pipe Connections on each end.
The collars are the same as used on our standard suction hose and
can be changed in the field, if needed. The horizontal strainer,
as shown, works well in this application. Caution: If severe low
water levels are encountered, it may be necessary to install legs
on the strainer to assure at least 6-8 inches of clearance is always
maintained between the strainer and pond bottom. Our horizontal
strainer works well as long as the hole pattern is submerged.
Mooring Buoys - Dry Hydrant Installation
Mooring buoys can be used for a variety of reasons.
They are great to indicate the end of a strainer in busy waterways
or can be used to support a suction hose or strainer when debris
or silt is a concern. It may also be used with the "PVC Flex
Joint" to maintain a constant suction depth for Dry Hydrant
installations.
Buoys are hard skinned and almost indestructible. Buoys are made
from high-density polyethylene, filled with closed cell foam. White
with blue florescent stripe. Highly visible to navigation. All come
complete with 3 ft of heavy-duty 2" plastic chain. Available
in 12", 15" or 18" Diameters.
| Mooring Buoys |
Assembly
Number
|
Diameter |
Buoyancy |
| 9769-612 |
12 Inches |
30 Lbs |
| 9769-615 |
15 Inches |
60 Lbs |
| 9769-618 |
18 Inches |
100 Lbs |
3 ft. PVC/Flex Joint as purchased
(click on image for larger view)
Flex Assembly with PVC Ends.
|
End view with collar.
|
PVC/Flex Joint Assembly
| Part
No. |
Size |
Description |
| 9681-000 |
6" |
PVC/Flex Joint Assembly |
5. Buried intake in a Sand or Gravel Bed
Placing an intake into the ground may seem like a crazy idea but
if done properly, can provide a clean abundant water supply. This
idea has been used in sandy soils with high water tables for many
years. Many Golf Courses get their water from long buried pipes
which lay buried horizontally in the ground.
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