MULTI-HAMMER DRILLS

MULTI-HAMMER DRILLS
MULTI-HAMMER DRILLS
Previous Next Play Pause
1
When drilling through rocks, conventional rock augers and buckets (and even core barrels) quickly lose their effectiveness as the strength of the rock begins to exceed 25 MPa. A solution employed in the past for pile drilling in hard rocks has been to use large diameter Down The Hole (DTH) hammers. However, not only are such hammers expensive to own and maintain, these hammers require inordinate quantities of air to operate effectively. Furthermore, whenever the DTH hammer develops a fault, the massive investment stops giving returns.

An effective solution for drilling of piles through hard rocks (and even boulders) is the Multi-Hammer Drill also known as Cluster Drill. This drill employs a set of small diameter DTH   hammers working inside a steel barrel with the hammers arranged in a geometry such that the complete pile diameter is covered by the hammer bits as the barrel is rotated (or oscillated) by the drilling rig.

The kelly box at the top of the barrel is attached to the standard drive stub of the kelly bar and air is supplied to the barrel through the kelly bar or through an inlet immediately below the kelly box from where it is distributed to each individual DTH hammer. As drilling proceeds and the cuttings are lifted upwards, these cuttings settle into a collection barrel sitting on top of the drilling barrel. Once the collection barrel becomes full, the drill is lifted out of the borehole and the collection barrel is pulled upwards by the auxiliary winch of the drilling rig to empty it of the cuttings. Subsequently, the drill is once again lowered into the borehole to proceed with the pile drilling.

Key Features

•    HEMCO heavy duty DTH hammers and bits.
•    Standard kelly stub of the piling rig is attached to the drill.
•    Drilling diameters from 610mm to 1200mm.
•    Easy to maintain in the field; for backup, small DTH hammers and bits suffice.
•    Special design allows quick change of hammer.
•    Low operation and maintenance cost.

Specifications

 Model
Diameter
 Diameter
 No. of
Recommended Air Required
 mm
 inches
 Hammers
 CFM
m³/min
MHD-610
610
24
3
1200 - 2000
34 - 57
MHD-750
750
30
4
1600 - 2500
45 - 71
MHD-800
800
32
4
1600 - 2500
45 - 71
MHD-900
900
36
4
2000 - 3000
57 - 85
MHD-1000
1000
40
5
2500 - 4000
71 - 114
MHD-1200
1200
48
6
3000 - 5000
85 - 142

 

 

Germany

Kompetenz f ü r den Spezialtiefbau,
Finkenweg 3, 56729 Ditscheid
Tel: +49 160 941 910 45
Email: germany@hemcoequipment.com

 

Singapore

600 North Road
Park View Road 188778,  
Singapore
Email: fareast@hemcoequipment.com