Heavy-Duty Material Handling for Wood Processing Industries | Rotary Airlocks & Screw Conveyors

Wood processing applications handle some of the industry’s most challenging bulk materials, including stringy, dusty, abrasive, irregular, and high-temperature wood byproducts. To prevent clogs, false air, and premature wear in sawmills, panel plants, pellet mills, wood waste, and cogeneration systems, PMM’s heavy-duty rotary airlocks and screw conveyors deliver reliable material handling performance in demanding wood processing environments.

  • Handle variable particle sizes (fines to oversized).
  • Designed to reduce bridging, packing and clogging.
  • Dust collection, pneumatic conveying and continuous fuel feeding.

  • Standard options include:

    • Abrasion-resistance.
    • Industry leading airlock functionality.

  • Application specific configurations:

    • Heat, moisture, abrasive materials
Chips, Bark, Hog Fuel, Shavings, Green Waste

Rotary Airlock Feeder w/ Shear Knife

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A heavy-duty metering device and airlock in one. Perfect for irregular or oversized wood particles. Knife options reduce jams and help maintain consistent feed into pneumatic lines, burners, and/or processing equipment.
Common in fly ash, bottom ash and dust collection systems.

High-Capacity Rotary Airlock Feeder

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An extremely heavy-duty, high-capacity rotary airlock built to move large amounts of abrasive, low-moisture fly and bottom ash under continuous, high-wear conditions.
Dust collection and pneumatic conveying systems.
Wet Sawdust, Resinous Fines, Variable Moisture

Self-Cleaning Rotary Airlock
Valve

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Designed to keep pockets clear when materials are prone to packing, sticking, or clogging. Prevents shutdowns in high-duty cycles and significantly reduces maintenance.
Engineered for abrasive ash, lime & carbon handling

Extremely Robust Rotary Airlock Valve

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Built for high-wear wood processing, wood waste, and dust collection applications, this extreme-duty rotary valve airlock features ultra-tight rotor-to-housing clearances and abrasionresistant materials to reduce leakage, improve airlock performance, and extend service life.
Pellets, Uniform Chips, Fragile Granules

Side-Entry Rotary Airlock Valve

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The offset inlet design allows this heavy-duty rotary airlock to gently handle biomass pellets of uniform size, minimizing pellet degradation, fines generation, and material loss during transfer.
Pellet Handling, Dust Collection, Baghouse
Handling the most challenging materials!

Heavy-Duty Screw Conveyors for Wood Processing

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Engineered specifically for wood manufacturing applications. PMM’s heavy-duty screw conveyors are built to match demanding operating conditions and outperform off-the-shelf augers under abrasive, high-load, and continuous-duty service.
PMM Specializes In Solving The Most Demanding Wood Manufacturing, Pneumatic Conveying, Bulk Material Handling Challenges

HD Rotary Airlocks & Screw Conveyors:

Sawmills & Planer Mills

Dimensional Lumber and High Speed Planer Mills

Materials Handled:
Wood chips, sawdust, planer shavings, bark, trim waste.

Common Material Handling Challenges:
Bridging, stringy carryback, dust leakage, wear at equipment inlets.

Typical Applications:

  • Cyclone and baghouse discharge airlocks
  • Pneumatic conveying systems
  • Wood chip fines separation and reclaim systems
  • Bark and hog fuel metering to burners
  • Dust collection system discharge

Typical Equipment Used:

  • Rotary airlock feeders, rotary valve airlocks, and screw conveyors.

Pellet & Briquette Mills

Wood Pellet, Biomass Pellet, and Briquette Plants

Materials Handled:
Sawdust, green and dry fiber, pellets, fines, and regrind.

Common Material Handling Challenges:
Material packing, moisture variation, pellet degradation, and dust control.

Typical Applications:

  • Dryer and hammermill discharge
  • Cooler or screen discharge
  • Baghouse and cyclone discharge
  • Pneumatic conveying and metering
  • Dust collection system discharge

Typical Equipment Used:

  • Rotary airlock feeders, rotary valve airlocks, and screw conveyors.

Panel & Composite Wood Mills

OSB, MDF, HDF, Particleboard, and Plywood Mills

Materials Handled:
Wood fiber, sanding dust, trim waste, and resonated materials.

Common Material Handling Challenges:
Abrasive dust, high air volumes, false air infiltration, and premature wear.

Typical Applications:

  • Pneumatic conveying and process metering
  • Dust collection discharge airlocks
  • Fiber reclaim and trim handling systems
  • Sander and press exhaust Systems

Typical Equipment Used:

  • Rotary airlock feeders, extreme-duty airlocks, and screw conveyors.

Furniture & Cabinet Manufacturing

Millwork, Cabinet, and Furniture Component Plants

Materials Handled:
Fine sawdust, shavings, trim waste, and sanding dust.

Common Material Handling Challenges:
Fine dust control, air leakage, and continuous production demands.

Typical Applications:

  • Central dust collection discharge
  • Pneumatic conveying systems
  • Trim and waste handling
  • Cyclone and baghouse airlocks

Typical Equipment Used:

  • Rotary valve airlocks and screw conveyors.

Engineered & Structural Wood Products

Engineered & Structural Wood Products

Materials Handled:
Sawdust, trim waste, wood fines, and process dust

Common Material Handling Challenges:
Continuous-duty operation, dust containment, and consistent material flow.

Typical Applications:

  • Saw line and trimming station dust collection
  • Pneumatic conveying systems
  • Trim reclaim and waste metering
  • Central dust collection discharge

Typical Equipment Used:

  • Rotary airlocks, side-entry rotary valves, and screw conveyors.

Wood Waste & Recycling Facilities

C&D Wood Processing and Residual Handling

Materials Handled:
Mixed wood waste, shredded material, fines, and contaminated wood.

Common Material Handling Challenges:
Inconsistent material size, abrasion, contamination, and plugging.

Typical Applications:

  • Waste reclaim systems
  • Fuel preparation and metering
  • Dust collection discharge
  • Pneumatic and mechanical conveying

Typical Equipment Used:

  • Rotary airlock feeders and screw conveyors.

Wood Manufacturing Bulk Material Handling – FAQ’s

Both rotary airlock feeders and rotary valve airlocks function as material metering devices while also maintaining airlock functionality between process zones. This dual functionality is critical in wood processing applications, where materials must be fed consistently while preserving pressure differentials in pneumatic conveying systems, dryers, and burners. Both designs also maintain airlock integrity at discharge points such as cyclones, baghouses, and dust collectors, especially where varying system pressures exist.
The primary difference in the wood products industry is in their construction, size and intended use. A rotary airlock feeder is equipped with a hardened tool steel shear knife, making it ideal for handling irregularly sized wood materials. The shear knife reduces oversized wood pieces before they enter a pneumatic conveying system, which reduces maintenance and downstream blockage issues. A rotary valve airlock, while not equipped with a shear knife, is manufactured using abrasion-resistant materials, making it well suited for dust collection applications and highly abrasive materials such as fly ash and bottom ash. Both are airlocks and both are metering devices! However, the difference is determined mainly by the type of material being conveyed.

Choosing the correct rotary airlock depends on several critical factors, including the material type, the material size, bulk density, moisture content, throughput requirements, and flow characteristics. Irregularly sized materials such as wood chips often require a rotary airlock feeder equipped with a shear knife to reduce oversized pieces and ensure consistent feeding. Sawdust or sanding dust, with its uniform particle size, is typically well suited for a rotary valve airlock with its abrasive-resistant materials and ultra-tight clearances to maximize airlock integrity. Wood pellets often benefit from a reduced-impact rotary airlock design, such as the side-entry rotary valve, which minimizes product degradation and breakage.

Selecting the proper airlock model and size is essential for reliable material handling performance. At Precision Machine & Manufacturing (PMM), every wood processing application is carefully reviewed by our technical team to ensure the rotary airlock or rotary valve is precisely matched to the material handling application, which includes the type of material being conveyed, the overall operating conditions, and the throughput requirements.

Wet sawdust and resinous wood fines can create material buildup, packing, and bridging inside rotary airlocks if not properly addressed. To prevent clogging, rotary airlocks for these wood processing applications often incorporate a self-cleaning rotor valve airlock design, in addition to surface treating the pockets to reduce material adhesion.

Proper inlet geometry and consistent feed rates also play a critical role in maintaining smooth material flow and reliable airlock performance when handling wet or sticky wood materials.

High-temperature wood processing applications, such as biomass burners and cogeneration systems, require rotary airlocks engineered with temperature-rated bearings, high-temperature shaft seals, and material-specific internal clearances. For this reason, PMM is one of the few rotary airlock manufacturers who routinely manufacturers rotary airlocks for high-temperature material handling applications. Thermal expansion is carefully considered in the design to maintain proper rotor-to-housing clearances without contact or excessive leakage. These heavy-duty rotary airlocks provide consistent fuel metering, maintain airlock integrity, and prevent false air infiltration in elevated temperature environments.

Ash and contaminated bark fuel are highly abrasive materials that require abrasion-resistant rotary airlocks designed for extreme wear conditions. These airlocks are built with hardened rotors, wear-resistant liners, reinforced housings, and protective surface treatments to withstand continuous exposure to abrasive wood byproducts. Design features such as thicker housings and strengthened inlet areas are also used to help minimize wear and significantly extend service life.

These abrasion-resistant rotary airlocks are commonly used in biomass, cogeneration, and wood waste fuel handling systems, where durability, uptime, and consistent material flow are critical. To further reduce premature wear in high-abrasion applications, Precision Machine & Manufacturing (PMM) utilizes a U.S.-sourced, through hardened steel alloy rated to 500 Brinell. This hardened alloy is used to manufacture the internal barrel (the primary material contact surface within the airlock) providing exceptional wear resistance and long-term performance in demanding ash and bark fuel handling environments.

Yes. Rebuildable rotary airlocks are widely used in biomass power and cogeneration plants to extend equipment life and reduce total cost of ownership. Rebuildable construction is especially valuable in high-wear wood processing, biomass, and ash-handling applications where continuous operation and long-term reliability are essential.

A key feature of Precision Machine & Manufacturing (PMM) rotary airlocks is they are designed to be fully rebuildable. Airlocks can be rebuilt at the factory and returned with a new factory warranty, significantly lowering overall lifecycle costs compared to purchasing a new airlock each time. In addition, PMM maintains a full inventory of replacement wear components for immediate shipment, allowing operators to minimize downtime by replacing worn parts onsite.

The modularity of PMM’s rotary valve allows individual wear components, such as rotors, endplates, seals, bearings, wear plates, barrel sides, and end bells to be replaced onsite without having to replace the entire unit.