FILTER SAND & GRAVEL

Red Flint Filter Sand and Gravel are naturally occurring, river washed, glacier deposit
products. Their excellent chemical properties- high in silica content and low in soluble calcium, manganese and iron compounds - meet AWWA-B100-89 specifications. Precision sizing and uniform grading to close limits meet the ridge specifications of professional engineers throughout the United States, Canada and overseas.

For over 50 years, red flint sand and gravel have been satisfying the requirements of
Industrial and municipal users, Red flint products have been specified and used nationally and internationally. Because of their high quality desirable chemical properties, color, an wide range of precision sizing.

FILTER SAND is graded specifically for use at water filtration plants. It can be used in municipal , industrial or residential applications.

The highly spherical shape of UNCRUSHED GRAVEL promotes good flow and even
Distribution. Being low in soluble impurities, it will maintain the quality of the treated water, especially in softeners. Three inch layers are recommended in graded support beds.

Advantages:

• Highly spherical shape and uniform grading provides reliable performance in this product with a long history of performance.
  
• Low soluble impurities prevent undesirable mineral leaching into process stream
  

Physical Properties:

• Color - Light Tan to Reddish Brown
  
• Density - 100 lbs./cu. Ft.
  
• Effective Size - .45 - .55 mm
  
• Uniformity Coefficient - 1.6 or less
  
• Acid Solubility - 0.3 - 1.6%
  
• Specific Gravity - 2.65 - 2.75
  

Conditions For Operation:

• Bed Depth - 18 - 30 in.
  
• Backwash Rate - 15 - 20 gpm/sq. ft.
  
• Backwash Bed Expansion - 35% of bed depth
  
• Service Flow Rate