|
| 4000 lb (1814 kg) of sand-silica
powder sprayed with liquid plasticizer in pneumatic blender
is delumped in 12 minutes using a Centri-Sifter centrifugal
screener. |
 |
| Centri-Sifter centrifugal
screener fits into tight space. Access door allows quick inspection,
cleaning and screen changing. Slide gate valve (rear) controls
flow rate of powder discharged from the blender into the screener. |
 |
| A 4000-lb (1814 kg) batch
of polymer concrete is bagged in 15 minutes. |
Centrifugal screener ups production of polymer
concrete by 75 percent
BERWICK, PA — Output of 35-75-lb (15.9-34.0 kg) bags of polymer concrete
at Castek, Inc. jumped 75% after replacing a rectangular vibrating
screen with a centrifugal sifter to remove lumps arising when sand
silica powder is sprayed with liquid plasticizer.
Previously, a 1'x 2' (25.4 - 50.8 mm) rectangular vibrating screen
sifted at a rate of 4000 lb (1814 kg) per hour. Frequent screen
blinding required the operator to continually scrape off and push
the soft lumps of semi-sticky powder through the screen. Screens
failed often while the uncovered screening chamber exposed the operator
to dust.
The Kason Centri-Sifter centrifugal screener sifts 4000 lb (1814
kg) in 12 minutes, and is fully enclosed to prevent dusting. The
operator no longer needs to tend the screener, instead assisting
a second operator in loading, unloading and verifying bag weights
at the pneumatic bagger capable of bagging a 4000-lb (1814 kg) batch
in 15 minutes.
Fits into Tight Space
The sifter sits on a narrow 20-ft (6096 mm) high mezzanine below
a 20-ft (6096 mm) high, 7000-lb (3175 kg) capacity pneumatic blender
and above a surge tank of same dimensions that feeds the Chantland
bagger at ground level.
Lumps of powder as large as 2-in (50.8 mm) form in the pneumatic
blender as liquid plasticizer is sprayed into the mixture of fine
and abrasive silica sand.
The free-flowing, friable granules are abrasive, with uneven shaped
particles ranging from fine to 1/16-inch (1.6 mm). Bulk density
is 100-lb/cu ft (1600 kg/cu.m), angle of repose 60%.
The powder flows from the bottom of the blender through a boot
and 8-in (203 mm) slide gate valve into the centrifugal sifter.
After adjusting the slide gate valve to control flow, the operator
can leave the sifter unattended.
In the Centri-Sifter screener, rotating helical paddles impart
centrifugal force to the particles, propelling them continuously
against and through a perforated plate cylindrical screen. The delumped
powder falls through the center of the separator into the surge
tank. A 5 mesh size stainless steel screen breaks even the smallest
lumps, with no waste exiting.
Requires Minimal Cleaning, Maintenance
Tony Krisanda, production manager, says all particles go through
the screen, leaving it clean, and requiring minimal cleaning or
maintenance. An easy access door with quick-release clamps allows
quick inspection, cleaning or changing of screens.
The sifter's 2' (50.8 mm) high by 3' (76.2 mm) wide frame and specially
mounted motor allow it to fit on the mezzanine.
Krisanda says he tried de-lumping with a lump crusher/shredder on
hand in the plant, but the sticky material lodged in the unit's
revolving fingers. He also rejected a circular vibratory separator
because it would be too large for the limited space.
During Castek's evaluation of the sifter, Chris Dugan, of Separator
Technology, Brown Mills, NJ, sent powder samples to Kason's laboratory,
which successfully screened them at the desired production rate.
The centrifugal screener runs intermittently according to customer
orders. Krisanda estimates if production were steady, the unit would
pay for itself in less than three months.
Produces High Strength Polymer Concrete
Castek produces 35-75 lb (15.9 - 34.0 kg) bags of high-compressive-strength
polymer concrete for patching and concrete rehabilitation in roads,
bridges, airport runways, and parking decks. Also produced on this
line is a 1/16-in (1.6 mm) thick flooring compound whose production
requires total elimination of lumps. The company is a subsidiary
of Transpo Industries, Inc.
|
