The DTH (Down-The-Hole) hammer is essential drilling equipment in mineral resources exploration, engineering geological surveys, and other fields. It holds significant application value, a link between the DTH drill bit and the drill jumbo, constituting a crucial working component of the DTH drill. According to different designs and applications, there are various types of DTH hammers, each with unique characteristics and scope of application.
According to the gas distribution method and structural characteristics, the DTH hammer has two kinds of valved and valveless.
The DTH hammer operates under the control of the valve piece within the gas distribution structure. It employs two exhaust methods: side exhaust and center exhaust.
The side exhaust DTH hammer is the earliest used, and the gas in its cylinder is exhausted from both sides of the drill bit.
The center exhaust DTH hammer releases gas through the center hole of the drill bit. It has a good pulverization effect, a long service life of the drill bit, high drilling efficiency, and is more suitable for the conditions and requirements of downhole drilling.
This hammer has no valve. The valve system that controls the reciprocating motion of the piston is arranged on the cylinder wall and automatically distributes the valve when the piston moves. Since this type of hammer does not use valves for gas distribution, it is called a valveless hammer. The working pressure of this type of hammer is lower than that of the valve type, and the impact energy generated under the same pressure is higher.
According to the rated working pressure, DTH hammers have low-pressure, medium-pressure, and high-pressure.
Low-pressure DTH hammer
The rated working pressure is 0.5～0.7Mpa. It is suitable for drilling under low-pressure conditions. It has a simple structure, easy operation, and low maintenance cost. However, low-pressure DTH hammers have lower drilling efficiency and are suitable for simple geological conditions and shallow drilling.
Medium-pressure DTH hammer
The working pressure of medium-pressure DTH hammers is generally 0.7 to 1.2Mpa, which is suitable for drilling under medium-pressure conditions. It has a lower component wear rate and a longer service life. However, the drilling efficiency of medium-pressure DTH hammers is lower than that of high-pressure DTH hammers.
High-pressure DTH hammer
A high-pressure DTH hammer has a working pressure of more than 1.2Mpa, which is suitable for drilling under high wind pressure conditions. It can provide higher impact and faster drilling speed. However, the components of high-pressure DTH hammers are prone to wear and require higher maintenance and replacement frequency.
To sum up, different types of DTH hammers have various characteristics and scope of application. When selecting a DTH hammer, you should consider the specific geological conditions and engineering needs and choose the most suitable one to improve the drilling efficiency and service life. In actual operation, you also need to pay attention to correct operating procedures and maintenance methods to avoid failures and extend the service life of the equipment.