Garnet is a
high hardness, high density granular filter media. It is normally used as the
lower (final) filtration layer of a multi-bed down flow filtration system. In a single media granular filter
such as a sand filter, the material will hydraulically classify during backwash
according to granule size, the smallest rising to the top. When water flows
downward through the sand, the fine particles at the top of the bed do most of
the straining of sediment. The solids form a cake on the surface with
filtration typically taking place in the top few inches. As the cake forms, the
filtration becomes finer and head loss increases exponentially in time.
The ideal
situation would be to have the large grains of media at the top to trap the
large solids and a uniformly decreasing grain size in the direction of fluid
flow with the small grains at the bottom to do the final polishing. The
penetration of the solids through the entire bed allows increased solids
storage, longer filter runs and higher filtration rates.
A properly
designed multi-media system will maintain its unique inverse void gradation and
provide superior performance even after long periods of use in backwash. This
stable condition of large grains above finer ones is achieved by the use of
materials of different sizes and specific gravities. Garnet with its high
specific gravity of 4.0 forms the lower fine grain layer, its 0.3mm effective
size can filter down to the 10-20 micron range.
#8 Garnet at
150 lb/ft3 is a good choice for support beds when using other high density
filtration media such as Corosex or the manganese dioxide
media such as Pyrolox.
Advantages:
- High
specific gravity allows unique filter designs. In combination with other filter
media both higher flow rates, higher loadings and better filtration can be
achieved.
- High
hardness reduces attrition and provides for years of reliable service.
- An excellent
support bed for other high density media.
Physical
Properties:
-
Color.......................................Light tan to reddish purple
- Type........................................Almandite
- Crystal
System.........................Cubic
-
Fracture....................................Sub-conchoidal
-
Hardness..................................7.5 (Moh's scale)
- Specific
Gravity.......................4.0
-
Density....................................120-150 lbs/cu. ft.
- Free Silica................................None
Price is Per KG