What is a cluster drill hammer?
The term "Cluster Drill Hammer" refers to a specialized drilling tool assembly that combines multiple down-the-hole (DTH) hammers or rotary drill bits mounted on a single drilling unit or frame. It is primarily used for large-diameter drilling applications in mining, quarrying, foundation piling, and oil/gas industries.
The technique of cluster hammer drilling has been validated for infiltrating rock structures of varying strengths, frequently surpassing 100 MPa. Cluster hammer drilling involves merging multiple separate drilling hammers into one steel cylinder. Drills for clusters come in sizes varying between 900 mm and 2400 mm.
For rock penetration, air pressure activates the pistons of each drill hammer in a cluster drill, causing the drill bit's hammering action to fragment the rock. A complete cluster drill rig requires multiple air compressors to provide enough air pressure to activate each of the drilling hammers and quickly flush the rock cuttings to the surface to maintain the efficiency of the cluster drill rig. Theoretically, however, the size of a cluster drill rig is limited only by the lifting capacity of the proposed equipment and transportation logistics.
Classification of cluster drill hammer
Cluster drill hammer can be divided into positive circulation cluster drill hammer and reverse circulation cluster drill hammer according to slag discharge mode; According to diferent operation modes, it can be divided into primary hole forming cluster DTH hammer, reaming cluster DTH hammer and ring cutting cluster DTH hammer.
According to slag discharge mode
The rock slag of the positive Circulation DTH hammer is discharged out of the hole or into the storage tank throu-gh the outside of the DTH hammer. The positive Circulation DTH hammer can be matched with various types odrilina rias . The rock slag of the Reverse Circulation DTH hammer passes through the slag discharge channel designed inside the cluster drill hammer and enters the inner slag discharge hole of the double wall dril pipe for slag discharge . The Reverse Circulation DTH hammer can only be used for the reverse circulation dril rig.
According to diferent operation modes
One time hole forming cluster DTH hammer is a cluster DTH hammer that can reach the size of pile hole in one operation. The pile hole of 1.5m and below can be operated by one-time hole forming positive and negative Circ-ulation DTH hammer. The reaming DTH hammer is mainly used to dril the small center hole in advance for thearae diameter pile hole more than 1.5m, and the reaming DTH hammer is used to expand the small diameter tothe desian diameter.
MWQCZ series combined hammer is the third generation of cluster DTH hammer developed by MW. Compared with the first and second generations of cluster DTH hammer, the third generation of combined hammer has lower cost better stability and higher return on operation. A set of hammers can meet a variety of operating apertures. The center hammer can be removed and used separately as a single hammer, and the removed center hammer can be used separately as a ring cutting hammer
The MWQCH ring cutting cluster DTH hammer is similar to the cone drill. The DTH hammer is used instead of the cone to break the rock ring groove. lt is mainly used in large diameter pile holes over 1500mm.
Advantages:
Enables large-diameter drilling in hard rock or complex formations.
Higher penetration rate due to simultaneous operation of multiple tools.
Reduces drilling time and cost for large projects.
Can be customized with different bit types depending on geology.
Conclusion
Cluster drill hammers are used for penetrating high-strength rock formations. They consist of multiple individual hammers within a single cylinder, powered by air pressure. Cluster drill hammers come in various types based on slag discharge methods and operation modes, such as positive or reverse circulation, available in diameters from 900 mm to 2400 mm, and are essential for large-scale drilling projects.
