Fibre cable blowing in city ducts is often scheduled at night to reduce traffic disruption. Night work means stricter noise limits, and one loud compressor can stop a project through complaints.
An LG Series electric unit was chosen: its low-noise acoustic design meets urban night-work limits, and its output is matched to the blowing equipment to avoid wasting energy.
No noise complaints during night work; blowing distance and success rate stayed consistent.
With site power available, M Series electric portable units were chosen: the DM250-31/25 (31 m³/min @ 25 bar) for high-pressure anchor drilling and DM185 units for medium-pressure grouting and hole cleaning. Motor output is unaffected by altitude and no fuel is needed.
DM250-31/25, DM185 series
132 kW and 185 kW electric units run in parallel with common receivers and pressure control. The DM185-26/21 runs continuously for base load and the DM138-23/19 starts and stops as faces open and close, so no unit runs at low load for long — and there is no diesel exhaust underground.
DM138-23/19, DM185-26/21
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
