Drawdown Hopper Product Profile

carman industries drawdown hopper
Carman Drawdown Hoppers eliminate outdoor stockpile storage and reclaim problems including Coring, Bridging, and Minimal Active Reclaim by using vibratory action to transmit energy directly into the stockpile, encouraging sloughing into the flow stream and maximizing active reclaim.

Individually engineered for each application, the unique design of the Carman Drawdown Hopper allows easy installation with the ruggedness to stay on-line.

To ensure proper application, Carman engineers carefully analyze the flow properties of your product or raw material in our laboratory and by using our exclusive computer analysis program.

eliminate ratholing on storage pile

Outdoor Storage Problems

Outdoor storage problems, including coring and bridging are usually related to compaction resulting from one or more of the following conditions:

  • High moisture
  • Heat or cold
  • Pressure of material on itself
  • Compaction caused by bullldozers and other material handling equipment
  • Continuous operation of drawdown hoppers


carman industries drawdown hopper eliminate coring

Coring occurs when the material in the core of the pile discharges, while material on the periphery resists movement.


carman industries drawdown hopper eliminate bridging

Bridging is the arch-like formation of material over either the static hopper inlet or outlet. It results from improperly designed hoppers or when the outlet is too small. Bridging also masks the location of the flow stream, a potentially dangerous condition for on-pile equipment operators.

Minimal Active Reclaim

minimal active stockpile reclaim

By utilizing a static hopper and feeder, active reclaim is limited to within approximately 40 degrees of the stored material’s natural angle of repose.

Carman Drawdown Hopper Solutions

carman industries drawdown hopper maximizes stockpile reclaim

A properly sized Carman Drawdown Hopper can economically eliminate outdoor storage problems.

Eliminate Coring

The projection ring of the Carman Drawdown Hopper, which is always exposed to the pile, transmits vibration and energy directly into the pile. As the central column of flow is drawn down, fracture lines encourage sloughing into the flow stream, eliminating coring.

Eliminate Bridging

Carman Drawdown Hoppers have command of the material equal to the Drawdown diameter. This results in an initial flow column equal to the inside diameter of the projection ring. A highly visible flow stream also improves on-pile equipment operator safety.

Maximize Active Reclaim

Carman Drawdown Hoppers consistently increase active reclaim to within 5 to 10 degrees of a material’s natural angle of repose. A Carman Drawdown Hopper can provide 4 to 5 times the reclaim of an equally sized static hopper with a feeder.

Drawdown Hopper Solutions At Work