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What is top hammer drilling?

Views:6     Author:Site Editor     Publish Time: 2020-04-01      Origin:Site

In tophammer drilling, rod joints transfer impact energy from the piston to the drill pipe. In addition, the rotational torque is transmitted through the handle adapter. Applications include underground mining, tunnels, and quarrying. It  also has many advantages, such as highly mobile, lower fuel consumption.

Excentric casing drilling system

This article contains the following aspects:

  • The introduction of top hammer drilling

  • Characteristics of top hammer drilling

  • Conclusion


1,The introduction of top hammer drilling

Drilling equipment is a collective term used to drill impact surfaces and blast holes on machines (in most cases) that apply impact and rotational forces. It is classified as top hammer drilling (THD), down-the-hole drilling (DTH), and rotary drilling. (RD) rig, depending on the method of operation. Generally speaking, top hammer drilling is mainly used in mining and civil blasting projects. Drilling rigs usually drill into the  1-20 meters deep, up to 40 meters; DTH is mainly used for groundwater development, and can drill holes up to 4000 meters deep; RD drill the deepest holes, the most common project is petroleum gas extraction and geothermal development. It is driven by its own weight and can reach the impact force of the Top hammer drill produced by the pump piston in a 10,000-meter-deep hydraulic drilling rig. 

The rod is passed to the drill bit, which is the difference between DTH drilling. At the same time, the impact system drives the drilling system to rotate. When the stress wave reaches the bit, the energy is transmitted to the rock in the form of bit penetration. The combination of these features allows drilling into hard rock, and the air compressor only performs dust and slag removal by hammer drilling at the top. The impact energy multiplied by the impact frequency produces the impact output of the drifter. However, under normal circumstances, top hammer drilling is used for hole diameters up to 127 mm and hole depths less than 20 M, which is highly efficient. Top hammer drilling is designed to transmit dense impact energy into the rock with as little energy loss as possible. The result is great rock break ability, high penetration, and high productivity. With the best drilling quality, high reliability and long service life, the best possible blasting effect, excellent drilling steel economy and lower overall operating costs. Top hammer drilling rigs are usually used for medium to hard rocks with hole diameters up to 230 mm.

Top hammer drilling include: hand-held rock drills (jacks, sinkers, stoppers), light rock drills mounted on feed devices, booms for tunnelling (large), medium to heavy crawler drills or with boom or mast wheel rig. 

Top hammer drilling combination:Percussion - Feed - Rotation - Flushing

Percussion: The energy generated by the impact rock drill is transmitted to the rock through the drill steel and the drill piston through the drifter. When the stress wave reaches the bit, the energy is transmitted to the rock in the form of bit penetration. The piston hits the shank, and the impact energy is transmitted to the drill steel in the form of a stress wave. The stress wave propagates at a speed of 5200 m / s. When using solid steel, the piston hits the stem directly. For longer steels, the piston hits the handle adapter. The impact energy multiplied by the impact frequency together produces the impact output of the drifter. Pneumatic drilling 1600 to 3400 strokes / minute, and hydraulic drilling 2,000 to 4500 strokes / minute.

2.Characteristics of Top hammer drill

1.Highly mobile

2.Best for holes between 25 and 127 mm in diameter. 

3.Under normal circumstances, the hole depth is less than 25 meters.

4.Adapt to stable and uniform hard rocks. 

5.The output medium is compressed air or water. 

6.Maximum inclination

7.Penetration is faster than DTH hammer drill. 

8.The size and depth of the highly maneuverable holes are limited (although recent advances in straight hole technology are removing this limitation). 

9.Reduce fuel consumption


How to choose among top hammer drilling (THD), down-the-hole drilling (DTH), and rotary drilling. (RD) rig depends on its operation method. At present, top hammer drilling is widely used in mining and civil explosion projects. Our company also provides high quality top hammer drilling and corresponding high-end services. Welcome to consult.



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