Deep in the tunnel, air you can count on
Drilling, shotcreting and mucking alternate all day — the DMT Series' full-range variable-speed drive removes the idle running of fixed-speed units
Help me chooseTypical challenges
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Alternating tasks make air demand swing widely
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Enclosed spaces echo and noise limits are strict
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Long supply cables, unstable voltage and high humidity
04
Fixed-speed units waste power running unloaded
What compressed air does here
Air for drilling
Drives DTH hammers or drill jumbos with steady rock-breaking power
Shotcrete support
Continuous air for shotcrete equipment keeps the spray dense
Mucking and ventilation
Works with the ventilation system to move air and control dust
Recommended configuration
Typical hole size / depth / duty
Depends on tunnel section and process
Recommended pressure & air delivery
Low pressure, high flow: 7–8 bar · 36–66 m³/min, stepless speed control
Recommended models
- DMT250-56/8View model ›
- DMT200-42/7View model ›
Results
Unloaded running at low demand is almost eliminated and energy use on long continuous supply drops noticeably; tunnel noise improved (from a hydropower tunnel project in southwest China)
Related case studies
Air supply for underground powerhouse tunnelling at a hydropower project in southwest China
A DMT tunnel unit was used: a permanent-magnet variable-speed drive loads to the actual demand curve, with a multi-layer acoustic canopy and isolation mounts.
DMT250-56/8
Air for secondary-lining shotcrete in a highway tunnel in western China
They switched to a DMT tunnel unit in a low-pressure, high-flow configuration (45 m³/min @ 7 bar), matching pressure to the job, with the variable-speed drive following the spraying rhythm.
DMT220-45/7
Recommendations
- The variable-speed drive has its own manual — have technicians familiar with VSDs service it
- Check the acoustic canopy and isolation mounts regularly
- Coordinate with the tunnel ventilation system
Tunnelling — FAQ
Does the DMT Series need grid power?
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Yes. DMT is fully electric with a permanent-magnet VSD, so the site needs power. Without a grid, choose an M Series diesel unit.
What noise limit applies in tunnels?
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Limits differ by region. The DMT's multi-layer canopy and isolation mounts are designed for enclosed spaces; we recommend measuring on site against your local standard.
How is a VSD different from a standard motor?
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A VSD varies speed steplessly to match actual demand, avoiding the repeated unloaded running of fixed-speed units at low demand.
