The front loader de-gritting system from Flo Trend Systems combines a gum-rubber-lined, steel-body hydrocyclone with a front loader container filter.

Underflow from the hydrocyclone and concentrated wet grit discharge into the container filter, allowing water to pass through and exit the discharge ports on the bottom of the unit. With a small amount of fines passing through at the beginning of the fill cycle, the Poly-2004 filter media can withhold particles 25 microns and larger.

The idea of combining a hydrocyclone and container filter originated with New York City in the mid-1990s. “They started buying dewatering boxes from us and were loading them with grit from multiple sources, one of which was the hydrocyclone,” says Russ Caughman, company vice president.

Hydrocyclones are typically used with dewatering screw conveyors for grit removal and dewatering, but the discharge can be quite wet and present a problem for disposal. A client suggested a dewatering box might be a better solution for producing dry cake. Flo Trend contacted a hydrocyclone manufacturer and built a frame to fit over the dewatering box.

“I don’t know if you’d consider that new technology, but it is, as far as we’re concerned,” Caughman says. “I know that our boxes have been used with hydrocyclones for grit removal here and there, but they don’t tell us how they’re delivering the grit to our dewatering boxes.”

The combination system positions the hydrocyclone at 11.5 degrees, rather than vertically. The result is a less watery discharge and more concentrated solids. A vacuum pump can be attached to the dewatering box to pull fluid through the grit for quicker dewatering.

The 6-inch hydrocyclone has a 2-inch vortex finder and 12-degree lower cone, delivering 90 gpm at 10 psi. The unit can remove 95 percent of particles 100 microns and larger with a specific gravity of 2.7 and greater. Featuring a 2.2-inch carbon steel inlet head, the hydrocyclone has a carbon steel housing with corrosion-resistant exterior coating.

The 2-cubic-yard filter dump container and frame are made of 10-gauge, 304 stainless steel plate with a 7-gauge, 304 stainless steel plate floor. The walls and floor are reinforced by 304 stainless steel structural angle and formed channel framing. Removable filter supports allow easy cleaning. Wall filters drain into the bottom cavity. Two 2-inch female-threaded drainage ports are located in the bottom of the interior support panel. Other features include lift brackets and four caster-type wheels for lateral mobility. 713/699-0152; www.flotrend.com.