Ideal Flow Velocities• Range between 0.48m to 1.07m or 1.6 to 3.5 ft./second.• Causes grit suspension in the flow, traveling like a moving bed.• Higher velocities (above 1.07m or 3.5 ft./second), the flow becomes turbulent dispersing the grit bed.• Lower velocities (below 0.48m or 1.6 ft./second), grit will settle & have limited movement.
Grit Removal Efficiency• 270 Degree or 360 Degree with Weir - 95% of 50 mesh grit and larger - 85% of 70 mesh grit but less than 50 mesh - 65% of 100 mesh grit but less than 70 mesh• 360 Degree w/ Baffling System - 95% of 140 mesh
Grit Piping Rules• Suction Piping Should be Kept to a Minimum (Less than 10’-15’)• Never Use Check Valves, instead use Pinch Valves• Use Good Screening Equipment Ahead of Grit Process (3/4” max. opening)
Grit Piping Rules• Remove All Grit From Basin• Use Water Flush Into Suction Line• May Run Flush Water While Pumping• Do NOT Depend on Gravity
Grit Piping Rules • Use Dedicated Suction & Discharge Lines for Dual Pumps • Eliminate Unnecessary Elbows • Use 45o Elbows if Necessary
PISTA WORKS® ™ Peak System Model Installed Footprint Flow CapacityModel 0.5 0.5 MGD 8-0 Wide x 18-0 High x 45-0 LongModel 1.0 1.0 MGD 8-0 Wide x 18-0 High x 45-0 LongModel 2.5 2.5 MGD 8-0 Wide x 18-0 High x 46-0 LongModel 4.0 4.0 MGD 8-0 Wide x 18-0 High x 47-0 LongModel 7.0 7.0 MGD 12-0 Wide x 18-0 High x 49-0 LongModel 12.0 12.0 MGD 12-0 Wide x 18-0 High x 49-0 Long