Cassette Systems

Oval Cassette

Oval Cassette







Schauenburg’s Round or Oval Cassette Systems are manufactured for use in Tunnel Boring Machine applications. Our cassettes’ strong all-steel construction is tough and durable to withstand a great deal of on-the-job abuse. The keys to our cassette design are simple installation and rapid payout of pre-loaded flexible duct.

Our cassette systems facilitates installation of flexible vent ducting in rapidly excavated headings and consists of three basic components: the outlet cone, the duct storage cassette (which houses the ventilation duct) and the ventilation duct. The unit is normally mounted at the face on the cutting machine, TBM continuous miner, etc., and moved forward with the unit.

As the flexible ventilation ducting is hung in the tunnel, the action of the TBM causes the duct to be automatically removed from the cassette and extended in the excavation. When the cassette unit is exhausted and substituted for a spare unit holding a full section of ducting, the empty unit is reloaded on the surface by support personnel.


  • Round or oval cassettes available
  • Diameters from 18 to 96 inches (450 to 2450 mm)
  • Cassette capacities from 300 to 1000 feet (92 to 308 meters)
  • Designed for the high pressures encountered in tunneling
  • Selection of materials from 13 to 24 oz/sq yd (450 to 800 g/m2)
  • Operates at positive pressure outflows
  • Utilizes a pre-loaded cassette that is refilled at the surface and taken to the work face as a complete unit

Shape/Capacity and Material

  • Round & Oval
  • Diameters 18″-96″ (450 mm – 2500mm)

Duct Capacity

  • 300′ – 1000′ (100 – 300 m)

Ventilation Duct

  • Designed for high pressures encountered in tunneling
  • 14 – 24 oz/sq yd material (450 – 800 g/m2)


  • Optional messenger line reel allows tensioned playout of messenger line as TBM advances
  • Optional cassette brakes for high-pressure suction (pressurizing fan running at cassette)

Cassette Outlet Cone

  • Allows gradual expansion of air to reduce shock loss or mounting of the reversing fan
  • Directs air from the pressure fan through the cone section while remaining attached to the fan during removal and installation of replacement cassettes
  • Provides additional support for the cassette and a tight connection between the cassette and TBM ducting

Cassette Storage

  • Site storage problems reduced as boxes holding duct can be stacked in small areas

Schauenburg cassettes’ outlet cones are designed to draw for orderly payout of ducting and smooth air flow through the cassette unit.

Our cassettes can hold from 300 to 1,000 feet (100 to 300 m) of pre-loaded lay flat material. Once expended, the cassette is refilled at the surface and returned to the work face as a complete unit for additional payout of duct into the TBM.

Fabric Color Weight Scrim
CD18 Yellow 18 oz/sq yd
(600 g/m2)
9 x 9 Fill 137 lbs/Warp 135 lbs
(62 kg) (61 kg)
CD24 White 24 oz/sq yd
(800 g/m2)
18 x 18 Fill 150 lbs/Warp 190 lbs
(68 kg) (86 kg)

Suction Systems




Blowing Systems


Fresh air is blowing into the tunnel through the duct.

The advantages of a Schauenburg Ventilation Blowing System are:

  • Workers on the TBM are in the cleanest possible air
  • Lower noise levels on TBM
  • Safest system in case of fire – toxic fumes cannot be sucked over the TBM workers.



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