Whether it is large or medium-sized horizontal directional drilling, its basic structure includes the main engine, drilling tools, steering system, mud system and intelligent auxiliary system.
The power system of the main engine is generally a diesel engine. As the power source, the diesel engine is one of the indexes to measure the construction ability of the drilling rig. However, the drilling rig often requires the rig to run at a constant load during drilling and retraction, so the continuous power of the engine is more important. In order to reduce labor intensity and improve labor efficiency, the host is generally equipped with an automatic drill pipe loading and unloading device. When drilling, the drilling rig automatically removes the drill rod from the drill rod box, and rotates and adds it to the drill rod string. When pulling back, the opposite is true. Some are also equipped with automatic lubricating oil smearing device, which lubricates the thread of the drill rod connector to help extend the life of the drill rod. The rig should be completely fixed during work. If movement occurs during drilling and dragging, on the one hand, it may cause engine damage, on the other hand, it will reduce the push-pull force and cause power loss in the hole. At present, the latest drilling rigs have automatic hydraulic anchoring systems, which rely on their own power to drill anchors into the soil layer. Generally, straight anchors are used in dry soil layers and spiral anchors are used in wet soil layers.
(2) Drilling tools
The drill pipe should have sufficient strength to avoid twisting and breaking, and must be flexible enough to drill curved holes. In the long-distance crossing, the length of the drill pipe directly affects the drilling efficiency, especially when the wire guide is used, the long drill pipe reduces the number of connection of the drill pipe, which will obviously save the connection time. The drilling direction is changed by controlling the direction of the Drilling Rig bit.
The drill bit is generally wedge-shaped. During the progress, if the drill bit rotates continuously, the drilling trajectory is a straight line. When the drill bit wants to bypass the obstacle or advance with a certain radius of curvature, the drill bit stops rotating, leaving the wedge surface at a certain angle before advancing. In this way, the bit advances in a direction opposite to the wedge surface. The swash plate of the drill bit usually has a nozzle, and high-speed mud is sprayed from the nozzle to wash the soil layer. Different bits should be used for gas and heat for different soil layers. For example, in softer clay, a bit with a larger size is generally selected to facilitate the change of direction during the advancement process. In the harder calcareous layer, use a smaller bit. For hard rock drilling, special drill bits are used, such as small-sized cemented carbide drill bits.
There are many types of reamers, and different reamers are suitable for different soil layers. For example, the groove-shaped reamer is suitable for sand and tight sand containing rocks, and it is easy to become spherical when running in high-viscosity clay; the rod cutter is suitable for hard soil and clay layers, but not in rocky ground Or run effectively on pebbles.
(3) Guidance system
The guidance system includes wireless guidance system and wired guidance system. The wireless guidance system consists of a handheld surface detector and a probe mounted in the drill bit. The detector judges the parameters such as the depth of the drill bit and the inclination angle of the wedge by receiving the electromagnetic wave signal emitted by the probe, and simultaneously transmits the signal to the display of the operation platform of the drilling rig so that the driller can adjust the drilling parameters in time to control the drilling. When crossing rivers and lakes, due to the difficulty of walking on the ground or the drilling depth is too deep, the electromagnetic wave signal is difficult to receive, you must use a wired guidance system. The probe transmits the signal to the console through the drill rod and then the cable. Because the cables must be manually connected by the drill rod, the use of the wire guide will take a lot of time.
(4) Mud system
The mud system is an important equipment to ensure the smooth expansion of the hole and the towing of the pipeline. After fully mixing and mixing the bentonite, water and additives in the mud tank, it is pressurized by the mud pump and sprayed from the nozzle of the Drilling Rig tool through the drill rod to wash the soil layer and take away the cuttings, which plays a role in assisting drilling. Drilling mud can cool the hole bottom drilling tool to avoid overheating and wear of the drilling tool. Another important role of drilling mud is to reduce the friction between the pipe wall and the hole wall when dragging the pipeline back. In the ideal state, the pipeline is suspended in the mud and pulled out, so in actual engineering, if the drilling is well formed, the pulling force of the pipeline is often much smaller than expected. The diameter of horizontal directional drill pipe holes is generally large, and the stability of the hole wall is poor. After the Drilling Rig mud solidifies, it can play a role in stabilizing the hole wall.
(5) Intelligent auxiliary system
The intelligent auxiliary system of drilling rig has developed rapidly in recent years. After the parameters such as the location of underground pipelines and obstacles, the type of drill pipe, the depth of Drilling Rig, the position of inlet and outlet, and the allowable bending radius of the pipeline are entered in advance, the drilling planning software can automatically design an optimal path, including the entry angle and the exit angle The specific position of each drill pipe can be adjusted according to the actual situation in the actual project.
Eternal Bliss Alloy Casting & Forging Co., Ltd.
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