Ash Handling Screw Conveyors

Extreme-duty, abrasion-resistant screw conveyors for moving fly ash and bottom ash away from boilers.  Designs include upgraded AR400 or Tri-Braze flights and upgraded materials of construction in the troughs for long-life in a harsh application.  Fly ash at 250° F and bottom ash at 600-700° F require materials and designs that tolerate continuous exposure to elevated temperatures.

Common Applications

  • Fly ash dust collection
  • Bottom ash collection systems
  • Biomass-fired power generation
  • Sawmill/board plant co-generation
  • Pulp & paper co-generation

Key Advantages

Materials and engineered designs assure a minimum of two years of operation before rebuilding might be considered.

Exceptionally straight-running screws (TIR of < 0.010” at the shafts and 1/16” at mid-span) to minimize deflective wear on troughs and on bushings, bearings and trough ends – reducing maintenance and repair costs.

Straight-running, properly-designed screws draw significantly less power – up to 50% less depending on the comparison.

Problems Solved

Abrasive applications where “off the shelf” screws wear out too quickly; increasing cost of ownership, threatening unplanned downtime, and/or disrupting power or steam production.

How It Works

  • Full-pitch screws engineered for relatively light loading of 25-30%.
  • Hard-facing on flights and pipe is typically not required; carbon steel pipe with wall thickness capable of minimal deflection is usually enough.
  • Mild steel flights wear out too quickly in most applications; upgrade to AR400 or Tri-Braze flights is recommended with Tri-Braze the preference for ash with high silica content.
  • Precision-bored pipe with matched bushings are a must for straight-running screws.

Technical Specifications

CategorySpecification
Material TypesFly ash at a typical bulk density of 30-45 lbs/ft³ with a very small/fine particle size distribution; little to no foreign, non-ash material; temperatures typically in the range of 250° F.

Bottom ash at an approximate bulk density of 40-45 lbs./ft³; granular structure, often with chunks and, in some fluidized-bed boiler systems, fused glass clinkers; typically, much hotter than fly ash with temperature in the range of 600-700° F or more.
Power RequirementsDrive motors powered by
230/460V 3Ph 60Hz
575V 3Ph 60Hz
Other voltages and frequencies available

Zero speed sensors operate at control voltage
VFD’s operate single-phase up to system voltage

Let our applications specialists help you with your extreme-duty bulk material handling needs.