Complete Grit Removal, Handling & Dewatering System Flow Scheme For maximum grit removal, the PISTA Grit Chamber should be complemented with Smith & Loveless PISTA grit handling and dewatering components, which transport, dewater and prepare the grit for final disposal. These components can be retrofitted to increase the efficiency of your grit handling system originally equipped with older components or non-smith & Loveless accessories. Smith & Loveless commitment to market leadership in grit removal kindles on-going research and development, which leads to continued system and component innovations. See the timeline below of key PISTA design milestones. Unparalleled Innovation For 30+ Years 1973 - PISTA Grit Removal System (70º) 1974 - PISTA Grit Screw Conveyor 1981-50 MGD PISTA Grit Chamber 198 - PISTA Grit Turbo Grit Pump (4 ) 198-175 GPM PISTA Grit Concentrator 1984-70 MGD PISTA Grit Chamber 1988-360º PISTA In-Line Design 1988-50 GPM PISTA Grit Concentrator 1989 - Parallel Plate PISTA Grit Screw Conveyor 199 - PISTA Grit Fluidizer 199-4 PISTA Grit Turbo Grit Pump 1998-6 PISTA Grit Turbo Grit Pump 1998-500 GPM PISTA Grit Concentrator 1999-100 MGD PISTA Grit Chamber 004 - PISTA Grit Flow Control Baffle 006 - PISTA Grit Stick Deflector PISTA Grit Removal System Components & Scheme [1] [] [3] [4] [5] [6] PISTA Grit Chamber Influent enters flat-floor grit chamber hydraulically guided by coanda ramp, internal baffles and central, low-speed propeller. Forced vortex drives grit particles to center chamber floor and into lower grit hopper while organics and flow continue to plant. PISTA Turbo Grit Pump Top-mounted or remote mounted unit pumps collected grit slurry (kept fluid by the PISTA Grit Fluidizer) to the PISTA s second-stage grit washing and dewatering system while also providing proper head. PISTA Grit Concentrator Specifically engineered for the PISTA system, this abrasion-resistant Ni-Hard unit washes grit further. It positions on the grit discharge line. PISTA Grit Screw Conveyor Grit from the concentrator deposits into the parallel (lamella) plate section of the S&L dewatering screw conveyor, which aids in retaining finer grit and reducing the stream s turbulence and overflow rate. Dewatered Grit Discharges from the top of the inclined screw conveyor into a container for disposal. The Flow and any Residual Organics are Returned to the inlet channel prior to the grit chamber, typically 93% of flow and 95% of organics.
The PISTA Turbo Grit Pump The PISTA Turbo Grit Pump s heavy-duty design provides maximum grit pumping efficiency for Smith & Loveless PISTA Grit Chamber grit hoppers. Designed specially for pumping grit slurry, the PISTA Turbo Grit Pump comes equipped with a Ni-Hard volute and recessed impeller (located separately Remote-Mounted Flooded Suction from the abrasive flow path) as well as the famous staples of S&L pump design: an oversized, stainless steel shaft and oversized bearings. This powerful combination yields reliable grit pumping and the velocity required for effective grit washing and dewatering devices, day-in and day-out for numerous years. PISTA Turbo Grit Pump Data Up to 500 GPM (31.5 lps) 4 & 6 Sizing Top-Mounted Vacuum Prime or Ni-Hard Impeller & Volute 1 Flexible Application: VP or FS PISTA Turbo Grit Pumps can be top-mounted (vacuum-primed with Sonic Start prime sensing) or remote-mounted (flooded suction). Topmounted units eliminate expensive piping while lowering the head and horsepower requirements and thereby lowering operational costs. Ideal Upgrade for Airlifts Older systems may employ airlifts, which are less efficient and require blowers to remove collected grit. The PISTA Turbo Grit Pump delivers more flow at a higher head, including at higher elevations. 3 How it Works As the hopper fills, the pump is triggered, eliminating continuous pumping. Remote-mounted, flooded suction examples PISTA Grit Chamber with topmounted PISTA Turbo Grit Pump Grit hopper from which removed grit is pumped 007 Smith & Loveless Inc. Bulletin 9503-9
The PISTA Grit Fluidizer The PISTA Grit FLUIDIZER is the ideal grit agitation device from the PISTA Grit Chamber s storage hopper. It s simple yet patented design attaches propeller vanes to the same shaft as the chamber s rotating 199 (PATENTED) paddles. These vanes Prevents removed grit continually stir the from compacting in the collected grit slurry grit storage hopper. Air scouring without any additional energy or controls. Larger PISTA Grit Chambers typically employ a water line to aid in keeping heavy grit loads soft while also flushing the discharge line prior to the next pump cycle. PISTA systems installed prior to the 1990s may not be equipped with a FLUIDIZER, instead relying on air scouring, which requires the use of additional mechanical equipment and energy. PISTA Grit Fluidizer Introduced: System Benefit: Upgrade from: 1 Fluidizing Action The PISTA Grit Fluidizer s patented, axial vanes are always rotating, keeping the grit fluid for easy pumping. Fluidized grit is less abrasive and less likely to compact. Attached to the propeller shaft, it does not require and valves, blowers or controls. Ideal Upgrade from Air Scouring Systems may employ air scouring, which can become a de facto airlift and actually dewater the grit stored in the hopper. This can make grit more difficult to remove. Additionally, air scouring may require blowers and associated equipment, which must be maintained and regulated. Grit hopper in which removed grit is continually fluidized until pumped to washing and dewatering Close-up of vanes 007 Smith & Loveless Inc. Bulletin 9503-10
The PISTA Grit Concentrator The durable PISTA Grit Concentrator, featuring a large discharge orifice, effectively functions as a primary grit washing and dewatering device. The PISTA Grit Concentrator separates the pumped flow into Primary grit washing & basic components of dewatering; compact water, organics, and 50-500 GPM (16-31.5 lps) grit. Working in concert with the PISTA Grit Screw Conveyor above which it snugly positions and discharges, the PISTA Grit Concentrator leaves grit clean with a sandy texture. Ninetyfive percent (95%) of the residual organics are removed, free from the organics that can become a smelly nuisance. PISTA Grit Concentrator Introduced: 198, 1988, 1998 Benefit: Sizing: 1 Large Orifice Minimizes Potential for Clogging The PISTA Grit Concetrator features an orifice that minimizes clogging because of its generous 3.5 (8.89 cm) diameter. Other systems typically contain orifices with diameters only measuring 1 - (.54 cm-5.08 cm) across. This means greater potential for plugging and the need for more frequent inspection. No Wearing Parts or Liners Unlike similar units, the PISTA design does not implement internally wearing parts like liners. This prevents downtime by eliminating need for routine disassembly. Instead, the PISTA Grit Concetrator relies on its rigid Ni-Hard iron, heavy-duty thick construction (1.5, 3.175 cm). The Smith & Loveless PISTA Grit Concentrator comes in two sizes, larger flow at 500 gpm (left) and smaller flow at 50 gpm (below). Both feature NiHard construction and Versapox epoxy coating. 007 Smith & Loveless Inc. Bulletin 9503-11
PISTA Grit Screw Conveyor The second-stage PISTA Grit Screw Conveyor is designed to work in concert with the complete PISTA Grit Removal System, providing superb dewatering and high retention of fine grit without the burden Lamella plate design of high maintenance. aids in retention of fine Dewatered grit grit while reducing turbulence & overflow discharges into a Screens container for disposal while the flow and residual organics are retuned to the inlet channel prior to the grit chamber, typically 93% of the flow and 95% of the organics. PISTA Grit Screw Conveyor Introduced: 1989 System Benefit: Upgrade from: Sizing: Models 15 & 17 1 Unique Design Elements Retain Ultra-Fine Grit The PISTA Grit Screw Conveyor s separate inlet zone, large Lamella parallel plate section that acts as a high-rate settling device, and double-sided weir trough work in concert to capture silt and and ultra fine grit. The inlet zone facilitates energy dissipation in order to reduce turbulence. This allows easier settling in the plate section while the larger weir trough lowers the carry-over rate. Ideal Upgrade for Screens Screens are typically maintenance-intensive because of their messy operation. Additionally, they can allow ultra-fine grit to be returned to the flow stream. The PISTA Grit Screw Conveyor greatly reduces maintenance concerns (and mess) while producing dryer grit. The PISTA Grit Screw Conveyor retains ultrafine grit and effectively washes and dewaters it for disposal all in a hassle-free operation. Lamella parallel plates facilitate high rate settling. 007 Smith & Loveless Inc. Bulletin 9503-1