The use of non-excavated reamers requires attention to the following aspects
1. Before assembling the drilling tool to the drill pipe, check the status of the drill bit or reamer. If it is a used drill bit or reamer, check it even more:
① Does the wheel frame move?
Is the rotation very loose?
③ Whether the palm tip part of the cone (the joint part of the back and the wheel) is too worn. If the rubber ring is exposed, it cannot be used any more.
④ Are the threads at both ends worn too much?
⑤ Is the nozzle size of cone suitable for the construction stratum? Is it unblocked?
⑥ Whether the centralizer is worn too much? The centralizer is generally 20-30mm smaller than the front hole (the centralizer of broken rock or pebble layer can be smaller than the front hole). The centralizer can stabilize the reamer and reduce the wear of the reamer and cone base. If the centralizer is worn too much, repair welding should be done in time.
⑦ Check whether the reamer matrix has open welding parts?
⑧ If it is a used drill bit or reamer, it is necessary to judge whether the reamer can be completed at one time according to the wear condition, crossing length, rock hardness, etc?
Wait.
The lower hole can be assembled only after the above inspection is completed and there is no problem.
2. During the construction process, as a manufacturer of tooth wheel drilling tools, we only give the following suggestions on drilling speed, bit pressure and mud displacement:
① Drilling speed: construction shall be carried out according to the speed stated in the attached instruction of drilling tool.
According to market research, most of the current drilling rig manufacturers do not have a meter to display the RPM of the drilling tool, that is, the number of revolutions per minute.
For example, the RPM of an 8 1/2 inch rubber-sealed cone bit is 60-100 r/min minutes, and it can be calculated that the rpm range of a 330mm reamer assembled with the cone blade of this 8 1/2 inch rubber-sealed cone bit should be 39-65; it can also be calculated that the rpm range of a 500mm reamer assembled with this 8 1/2 inch rubber-sealed cone bit should be 26-43.
After market research, the RPM of most cone reamers has not received due attention during use, causing the rubber seal ring to lose its sealing effect on the bearing prematurely due to the number of revolutions per minute exceeding the use range.
The metal seal is a high-speed drill bit, and the speed that can withstand is about twice that of the rubber seal. At a higher speed, the metal seal still has a sealing effect on the bearing.
This also has to make us think, whether it is possible to increase the service life of the rubber sealing cone by increasing the tension and controlling the speed?
Although rubber-sealed cones and metal-sealed cones may be slightly different in terms of comprehensive constitution, the difference is very small. The main difference is still in the speed and life of the bearing. If we use the rubber-sealed cones, can we save a lot of drilling tool costs? This is just a thought, and we can study it.
② Bit pressure. In oil drilling, we generally call it drilling pressure, and in trenchless excavation, it is called pulling force.
When using the cone reamer, we should pay attention to the pulling force, and do not exceed the pulling force range in the instructions attached to the product.
Especially when assembling smaller diameter reamers such as those below 300mm, it is inevitable that smaller cone palms will be used, and more attention should be paid to the fact that the pulling force cannot exceed the use range.
As for mud, as a roller drilling tool manufacturer, the construction experience is little, only the following suggestions can be given.
Pay attention to the ratio of mud, observe the instrument during use, and judge the sand-carrying situation of mud. As a drilling tool manufacturer, we hope that during the work of the drilling tool, the broken large rocks will be drained away as soon as possible, instead of repeatedly breaking in the hole, causing excessive wear and washing to the teeth and matrix of the cone. If the sand carrying performance of the mud is poor, the construction progress will be greatly reduced.
After the stoppage, the construction must be started again to increase the displacement of sand. According to our experience, the time when the drilling rig is restarted in the morning is the time when sticking occurs most.
3. Maintenance and storage of drilling tools
① Whether it is a cone bit or a reamer, it must be rinsed with clean water after use, and the use of drilling tools must be recorded.
The records include: project name, location, trip-in time, hole-out time, effective drilling time (minus rest time), crossing length, average pulling force, rotating speed, rock type hardness, drilling tool wear, etc.
If the drilling tool is worn too much, it should be repaired in time to facilitate the next use.
② When flushing the drilling tool with clean water, be sure to pay attention to flushing the thread and cleaning the thread end face, apply thread oil and assemble thread guard cap after wiping dry. If there is no silk guard cap, it can be wrapped in ordinary packaging such as bubble wrap to avoid bumping.
③ Even if it is a metal-sealed cone bit, there is a rubber sealing ring inside. Long-term exposure to the sun will affect the sealing performance of the rubber. Whether it is a metal-sealed roller cone drill or a rubber-sealed roller cone drill, it must be placed in a cool and dry place. Composite seal is a kind of rubber seal, also need the same treatment.