One of the nation’s leading cement producers required a reliable feeding solution to meter synthetic gypsum into their manufacturing process. After reviewing B.W. Sinclair’s design and operational approach, the client specified four BWSI multi-screw Live Bottom Feeders, engineered specifically for the sluggish, cohesive handling characteristics of synthetic gypsum (calcium sulfate).
The Challenge
Synthetic gypsum is a byproduct of flue-gas scrubbing systems at coal-fired power plants. Cement producers use it as a process additive, but its handling characteristics make consistent metering difficult with standard equipment:
- Cohesive and prone to bridging in conventional hoppers
- Sluggish flow that defeats single-point discharge feeders
- Variable moisture content that shifts bulk density and flow behavior
- Abrasive enough to accelerate wear on standard flight profiles
The B.W. Sinclair Solution
We supplied four multi-screw live bottom feeders in 4-screw and 6-screw configurations, sized to the client’s storage hoppers. The design combines notched spiral flight geometry, counter-rotating agitation, and variable-speed drive control to produce consistent mass flow regardless of material condition.
The rotors are fitted with interrupted helix notched spiral flights fabricated from abrasion-resistant steel. The notched profile allows higher rotational speeds than standard continuous flights and produces a better mass-flow discharge pattern across the full hopper cross-section, preventing the channeling and rat-holing that causes flow interruption in cohesive materials.
Every other rotor uses reverse-hand flighting, creating counter-rotating agitation across the hopper floor. This continuous cross-agitation breaks up bridging and packing before it can develop, ensuring consistent flow without operator intervention.
An integral collector screw conveyor is bolted directly to the discharge throat of each feeder, consolidating output from all screws into a single spout for transfer to the next conveyor in the system.
Equipment Used
- Units Supplied: Four multi-screw Live Bottom Feeders
- Configurations: 4-screw and 6-screw modules, sized to hopper
- Flights: Interrupted helix notched spiral, abrasion-resistant steel
- Agitation: Counter-rotating rotors via alternating reverse-hand flighting
- Slave Drive: Precision-machined spur pinion gears in continuous lubricant bath
- Bearings: Dodge Type E-xtra™ tapered roller bearing flange blocks
- Primary Drive: Dodge Quantis™ helical gear reducer, 25 HP DC variable-speed motor, roller chain primary
- Discharge: Integral collector screw conveyor to single transfer spout
The Result
The four B.W. Sinclair live bottom feeders solved the flow and metering challenges that conventional equipment could not reliably handle. The notched spiral flight design, counter-rotating agitation, and variable-speed drive work together to deliver consistent, controlled feed rates, enabling the cement producer to incorporate synthetic gypsum as a reliable process input at scale.
Sluggish Materials? We Engineer for That.
Our live bottom feeders are proven across a wide range of sluggish, cohesive, and abrasive bulk materials. Contact our engineering team to discuss a purpose-built solution for your application.
