Since its inaugural installation at Crowley, Texas-based Charley's Concrete in 1998, the BFK Concrete Reclaimer has undergone a series of design changes and system upgrades resulting in a new model named the Snubnose 1000.

The initial Concrete Reclaimer design utilized an inner rock screen and outer fine screen wrapped around a central rotor for separating the material from wet concrete. The new design eliminates the fine screen and replaces it with a rock screen. What led to the design change was Brent Pennington of Charley's Concrete, who noted that the unit reclaimed material when it was operated without the fine screen an observation made after the fine screen had been damaged and removed. Based on his findings, BFK designed a prototype Snubnose 1000 with only a rotary rock screen. The new equipment was tested and fine-tuned at Wisconsin's Sheboygan Concrete, with the cooperation of plant owner Mike Harvey and plant manager Dave Jindra.

Mechanical changes

The Snubnose 1000 was developed by strategic placement of water jets, modifications to the lower shroud, and a large 2.5-ft.-diameter rotary rock screen for increased surface area. Screen length was shortened from 9 to 5 ft. while maintaining the same high throughput capacity of to 1 yard per minute. The result of this change included a reduction in equipment size to a footprint of 8 12 ft. from 8 16 ft. Also, the Snubnose now handles fiber with reported ease, as there is no fine screen to blind with most of the fiber passing out with the rock.

In addition, BFK reports, the need for a rock conveyor was eliminated and attendant operating costs reduced by adding 2 feet to the height of the mounting pad and truck ramp, increasing the elevated height of the equipment allowing the rock to be discharged directly to the ground. A more efficient Concrete Reclaimer emerged from the new design, lowering energy consumption with the reduction in required motor horsepower and one less drive motor with the elimination of the rock conveyor.

The Snubnose 1000 operates using two (2) direct drive 5-hp gear motors to drive the sand dewatering screw and rotary rock screen plus one (1) 5-hp submersible water pump for a total of 15 hp. The estimated electrical cost to operate the three motors is $1,700 a year @ 4.5 cents per kwh. Also, since the system operates on demand, energy usage is kept to a minimum a very important feature, BFK contends, considering the current energy problems. Because the system operates on demand and completes the reclaim cycle in six minutes, there is no need for an auxiliary power supply to back up large holding tanks used with a rebatch system.

After testing was completed on the prototype Snubnose 1000 at Sheboygan Concrete, BFK converted Charley's Concrete's two existing reclaimers to the newer version. Based on the performance of these units Charley's ordered two new models for other plants.

The elimination of the sand screen and belt conveyor with an overall reduction in size lowers equipment costs, translating into a shorter payback period. A 13-truck plant operating nine months a year will pay for the Snubnose in one year, BFK officials figure, based on a plant operating 20 days per month using a historical material savings of $21 per truck per day. The material savings for a 13-truck plant amounts to nearly $50,000 and does not include savings from disposal costs.

For information on the Snubnose 1000 Reclaimer, circle 203 on Reader Card

Snubnose 1000

Operation and maintenance

The Snubnose 1000 Concrete Reclaimer system comprises a spray washing process consisting of spray nozzles/jets and a 300-gpm submersible pump that re-circulates clean water from the settling pond back to the reclaimer. An 8-ft. wide, 1.33-cu.-yd. dump hopper coupled with a capacity of 0.5 to 1 yd. per minute allows two trucks at a time to unload concrete into the Snubnose 1000. An electric control panel controls the electric motors, pump and optional auto on/off loop detector.

At the time of discharging concrete from the mixer truck, the system is turned-on either manually or automatically with a loop detector. Water is added to the mixer truck and concrete is then discharged down the chute into the dump hopper. A spray nozzle in the hopper adds water to the concrete to prepare it for feeding into the reclaimer. A 14-in.-diam. infeed auger in the dump hopper controls the flow of concrete into the reclaimer rock screen and prevents overwhelming the screen guaranteeing very clean rock, according to product engineers. Covering the infeed auger is an adjustable restrictor plate to keep operators safe and also help restrict the amount of wet concrete that can be fed into the reclaimer. The infeed auger is coupled to the rotary rock screen shaft requiring only one drive motor.

Wet concrete fed into the reclaimer via the infeed auger passes over the ¼-in. opening, 14-gauge, 2.5-ft.-diam. 5-ft.-long rotary rock screen where the rock is washed clean and separated from the sand and spent cement as it passes over the screen to stockpile. The sand and spent cement pass through the rock screen with the heavier sand falling to the bottom of the shroud, settling at the base of the heavy-duty 24-in.-diam., ½-in. sectional abrasion-resistant flighting sand dewatering screw. Here the sand is carried up the dewatering screw while being washed clean with a counter-flow spray nozzle and out to stockpile. An optional heated jacket at the base of the sand screw keeps the sand from freezing in cold weather operations, eliminating the need to drain water from the sand screw.

The lighter spent cement gravity flows out an 8-in.-diam. bottom drain to the settling ponds. After six minutes the system is manually or automatically shut-off when the truck leaves and “trips” the loop detector.

The Snubnose has three lubrication points consisting of three bearings mounted outboard for easy access for greasing or replacement, should it become necessary. The manufacturer recommends greasing once every two weeks. There are no high-maintenance and expensive rubber tires, roller casters or large belts. All drives are directly coupled to the driven shafts eliminating the maintenance headaches associated with sheaves, v-belts, sprockets and chains. With seven bolts holding the rock screen in place, screen replacement is reportedly simple and fast.