Two 72" (1829mm) diameter Kason low-profile Flo-Thru Vibroscreen® circular vibratory separators are mounted on holding bins that discharge urea, phosphates and potassium granules into bagging machines below. Screeners prevent separation of ingredients having disparate bulk densities to roduce a uniform fertilizer product..

Low-profile 72" (1829mm) diameter Flo-Thru Vibroscreen® separator fits in 60" (1524mm) space between ceiling and holding bin that receives on-size material. Oversize particles >0.125" (3.175mm) exit through side discharge spout.

For a professional grade lawn fertilizer to yield quality results, its chemical components must be blended thoroughly and remain uniformly distributed until the time of application, despite variations in the bulk density and particle size of ingredients. The fertilizer blend must also be free of large particles, agglomerates and foreign matter to prevent plugging of small orifices in spreading equipment, which can leave unfertilized streaks on golf courses and professionally managed lawns.

Randy Nandory, EC Grow, Inc.production manager, says, "In recent years, EC Grow has transformed good products into professional grade products." Quality improved as the company replaced four 96"x 96" (2438 x 2438mm) static sieves with four Kason low-profile 72" (1829mm) diameter Flo-Thru Vibroscreen^® circular vibratory separators that screen granules down to a 75 percent smaller size (0.125" [3.175mm] instead of 0.5"[12.7 mm]), producing a finer, more uniform product. The vibratory screeners also prevent the separation of blended products that previously resulted from wide variations in the bulk densities of ingredients.

Static sieves caused screen blinding
Vibratory action enables the Kason screeners to match the static sieves' 120-ton/hour capacity using the finer mesh screens without screen blinding or segregation of blended ingredients. Previously,oversize fertilizer particles caused screen blinding that required operators to remove, clear and re-install the screens. The static sieves also caused separation of ingredients having disparate bulk densities, with urea (nitrogen compound) at 48-50 lb/cu ft (768-800 kg/cu m), phosphates at 54-56 lb/cu ft (864-896 kg/cu m), potassium at 70-75 lb/cu ft (1120-1200 kg/cu m), and trace minerals as high as 90-lb/cu ft (1440 kg/cu m).

Production of fertilizer granules
Urea,phosphates and potassium granules delivered by bulk transport trucks are stored in 50-1000 ton holding bins. Ingredients are weigh-batched according to product recipe, and transferred to one of three 250 cu ft (7075 l) capacity blenders where pesticides,pre-emergents,broadleaf or dust control agents are applied. Each blended batch is conveyed to any of four 6-ton capacity holding bins through the top-mounted 72"(1829mm) diameter low-profile circular vibratory separators. The bins feature honeycombed mixing baffles that promote blending as particles descend to each discharge spout.

The circular vibratory screeners scalp agglomerated particles,wood, metal, plastic and other foreign material larger than 0.125"(3.175mm),while on-size particles fall through the bottom outlets into the holding bins and bagging machines below.

During humid summer months, the hygroscopic fertilizer tends to agglomerate and blind screen apertures, a problem rectified using an antiblinding ball tray assembly in which elastomeric balls bounce between the upper operating screen and lower ball support screen,dislodging granules from screen apertures.

Circular separators prevent segregation
Unlike the static sieves which caused the material to pile on the screens and segregate, the low-profile Flo-Thru circular vibratory separators employ two externally-mounted imbalanced-weight gyratory motors that cause on-size particles to pass through the screen in a vertical straight-through path at high rates with no segregation of ingredients.

Fits in restricted overhead space
The low-profile units also solved an overhead space restriction problem, being the only screeners that could fit within the 60"(1524mm) gap between the ceilings and holding bins. Two externally mounted motors (as opposed to one motor mounted beneath the screening chamber) reduce the unit's height to 36"(914mm) versus 72" (1829mm) for a conventional separator of equivalent diameter.

Having tripled in size, EC Grow has added three low-profile screeners since purchasing its first Kason unit in 1994.