Down-the-hole drilling rig, you may not have heard of this kind of equipment, right? It is a kind of drilling machine, which is often used for drilling rock anchor holes, anchor holes, blast holes, grouting holes and other drilling constructions in urban construction, railway, highway, river, hydropower and other projects. In this article, Xiaodian will give you a detailed introduction to the structure, working principle and classification of down-the-hole drilling rigs. let’s see!
Mechanism composition of large surface down-the-hole drilling rig.
1. Drill stand: The drill stand is the guide rail for the sliding of the slewing device, the advancement and lifting of the drilling tool.
2. Compartment: The carriage is a square box structure welded by steel plates, which is used to connect and support the drill frame.
3. Rotary device: This mechanism is composed of hydraulic motor, spindle mechanism, pressure head, slide plate and central air supply mechanism. The chain of the propulsion mechanism is fixed on the slide plate through the pin shaft and the spring damping mechanism.
4. Propulsion mechanism: The propulsion mechanism is composed of a propulsion hydraulic motor, a sprocket set, a chain and a buffer spring.
5. Rod unloader: The rod unloader is composed of upper rod body, lower rod body, clamping cylinder and rod output cylinder.
6. Dust removal device: The dust removal device is divided into several methods such as dry dust removal, wet dust removal, mixed dust removal and foam dust removal.
7. Walking mechanism: The walking device is composed of a walking frame, a hydraulic motor, a multi-stage planetary reducer, a crawler belt, a driving wheel, a driven wheel, and a tensioning device.
8. Frame: air compressor unit, dust removal device, fuel tank pump unit, valve group, cab, etc. are all installed on the frame.
9. Fuselage slewing mechanism: This mechanism is composed of slewing motor, brake, deceleration device, pinion, slewing bearing and so on.
10. The yaw mechanism of the drilling rig: this mechanism is composed of yaw cylinder, hinge shaft and hinge seat, which can make the rig yaw left and right and adjust the drilling angle.
11. Compressor system and impactor: The compressor system is generally equipped with a screw air compressor to provide compressed air for the jet cleaning system of the high-pressure impactor and laminar flow dust collector.
Basic composition of general-purpose down-the-hole drilling rig
Drilling tools are composed of drill pipe, button bit and impactor. When drilling, use two drill pipe adapters to drill into the stainless steel plate. The rotary air supply mechanism consists of a rotary motor, a rotary reducer, and an air supply rotary device. The slewing reducer is a closed heterosexual part of the three-stage cylindrical gear, which is automatically lubricated by a spiral oiler. The air supply rotary device consists of a connecting body, a seal, a hollow shaft and a drill pipe joint. Equipped with pneumatic clamps for connecting and unloading drill pipe, Photinia. The lifting pressure adjustment mechanism is lifted by the lifting motor with the help of the lifting reducer, lifting chain, slewing mechanism and drilling tool. In the closed chain system, a pressure regulating cylinder, a movable pulley block and a waterproof agent are installed. When working normally, the piston rod of the pressure regulating cylinder pushes the pulley block to make the drilling tool realize decompression drilling.
Working principle of down-the-hole drilling rig
The working principle of the down-the-hole drilling rig is the same as that of the ordinary impact rotary pneumatic rock drill. Pneumatic rock drills combine the impact slewing mechanism, and transmit the impact to the drill bit through the drill rod; while the down-the-hole drilling machine separates the impact mechanism (impactor) and dives into the bottom of the hole. No matter how deep the drill is, the drill bit is directly installed on the impactor, and the impact energy is not transmitted through the drill pipe, which reduces the loss of impact energy.
With the increase of drilling depth of down-the-hole drilling rig and rock drilling machine, the loss of rock-drilling capacity of down-the-hole drilling rods and joints (medium hole, deep hole drilling), etc. increases, the drilling speed decreases significantly, and the cost decreases. In order to reduce production loss, improve Drilling efficiency, a down-the-hole drilling rig is designed in actual engineering. The down-the-hole drilling rig is also powered by compressed air, and its working principle is that the pneumatic impactor of the down-the-hole drill is installed on the front end of the drill pipe together with the drill bit. When drilling, the propulsion mechanism keeps the drilling tool moving forward, exerts a certain axial pressure on the bottom of the hole, and makes the drill bit contact with the rock at the bottom of the hole; Under the action, the piston reciprocates and impacts the drill bit to complete the impact on the rock. Compressed air enters from the rotary air supply mechanism and reaches the bottom of the hole through the hollow rod, and the broken rock powder is discharged from the annular space between the drill pipe and the hole wall to the outside of the hole. It can be seen that the essence of down-the-hole rock drilling is the combination of two rock crushing methods, impact and rotation. Under the action of axial pressure, the impact is intermittent and the rotation is continuous. Under the action, the rock is continuously broken and sheared. force and shear force. In down-the-hole rock drilling, impact energy plays a leading role.
Classification of down-the-hole drilling rigs
The structure of the down-the-hole drilling rig is divided into two types: integral type and split type. According to the exhaust method, it is divided into two types: side exhaust and center exhaust. It is divided according to the shape of the inlaid carbide on the working surface of the down-the-hole drilling machine. There are blade DTH drills, column tooth DTH drills and blade-to-blade hybrid DTH drills.
The integral down-the-hole drilling rig is a single-body down-the-hole drilling rig composed of a head and a tail. It is simple to process and convenient to use, which can minimize the loss of energy transmission. The disadvantage is that when the working face of the down-the-hole drilling machine is damaged, it will be scrapped as a whole. The model down-the-hole drilling rig is separated from the tail (drill tail) of the down-the-hole drilling rig, and the two are connected with special threads. When the head of the down-the-hole drilling rig is damaged, the drill tail can still be retained to save steel. However, the structure is more complex, and the energy transfer efficiency is reduced.
Post time: Apr-25-2023
