Suggestions on the use and maintenance of trenchless roller bit and roller reamer

When using trenchless reamer, attention should be paid to the following aspects:

1> Before assembling the drill to the drill pipe, check the state of the drill bit or reamer, especially if it is a used bit or reamer:

① Is the wheel frame moving?

Is the rotation very loose?

(3) Whether the tip part of the roller palm (the back part of the wheel) is too worn, if the apron is exposed, it can not continue to use.

Whether the threads at both ends are worn too much?

Is the size of the cone nozzle suitable for the construction stratum? Is it clear?

⑥ Centralizer wear too much? The centralizer is generally smaller than the front hole 20-30mm (the centralizer of broken rock or pebble layer can be smaller than the front hole), the centralizer can stabilize the reamer, reduce the wear of the reamer and the matrix of the cone, if the centralizer wear is too large to repair welding in time.

Check whether the reamer has welding parts?

⑧ If it is used drill or reamer, need to judge whether the reamer can be completed at one time according to the wear, through length, rock hardness and so on?

And so on.

After the above inspection is completed and there is no problem, the lower hole can be assembled.

2> In the construction process, as the manufacturer of roller cone drilling tools, we just give the following suggestions on speed, bit weight and mud displacement:

(1) Speed: according to the speed on the drilling tool instruction.

According to market research, most rig manufacturers currently do not have gauges showing RPM, or revolutions per minute, of the drill string.

For example, an 8 1/2 inch rubber sealed cone bit with an RPM of 60-100 RPM can be calculated to have a 330mm reamer assembled with the cone pads of this 8 1/2 inch rubber sealed cone bit with a RPM range of 39-65 RPM. It can also be calculated that a 500mm reamer assembled with the cone pads of this 8 1/2 inch rubber sealed cone bit should have a range of revolutions per minute from 26 to 43.

After market research, it is found that the RPM of most cone reamer has not received due attention in the use process, resulting in the premature loss of sealing effect of rubber seal ring on bearings due to the number of revolutions per minute beyond the range of use.

Metal seal belongs to high speed drill, which can withstand about twice the speed of rubber seal. At higher speed, metal seal still has the sealing effect on bearings.

This also has to make us think, whether we can improve the service life of rubber sealing roller by increasing the tension and controlling the number of revolutions?

Rubber sealed cone and metal sealed cone although there may be a slight difference in the comprehensive constitution, but the difference is very small, the main difference is in the speed and life of the bearing, if we use a good rubber sealed cone can save a lot of drilling cost? This is just a thought, and you can look into it.

(2) the wob. In oil drilling we call it weight on bit and in trenchless we call it tension.

When using the cone reamer, we should pay attention to the tension, not beyond the range of tension on the product instructions.

Especially in the assembly of smaller diameter reamer such as less than 300mm, it is inevitable to use a small cone plate, but also need to pay attention to the tension can not exceed the range of use.

③ As for mud, as a roller drill manufacturer with little construction experience, we can only give limited suggestions as follows.

Pay attention to the proportion of mud, observe the instrument in the process of use, judge the mud carrying sand situation. As a drilling tool manufacturer, we hope that in the work of drilling tools, the broken large rocks are discharged as soon as possible, rather than repeatedly broken in the hole, causing unnecessary wear and washing to the teeth and matrix of the tooth roller. If the mud carrying performance is poor, the construction progress will be greatly reduced.

After stopping midway, it is necessary to increase the displacement of sand to start construction again. According to our experience, the most stuck drill occurs when the drilling rig is restarted in the morning.

3> Maintenance and storage of drilling tools.

(1) Whether roller cone bit or reamer, after use must be washed with water, do a good record of the use of drilling tools.

Records include: project name, location, trip time, exit time, effective drilling time (minus rest time), traverse length, average pull, rotational speed, rock type hardness, drill tool wear, etc.

If the drilling tool wear is too large to repair in time, convenient for next use.

(2) When the drilling tool is cleaned with water, attention must be paid to washing the thread and cleaning the end face of the thread. After drying, apply the thread oil and assemble the thread protection cap. No silk cap can be wrapped with bubble wrap and other ordinary packaging to avoid bumping.

(3) Even if it is a metal sealed cone bit, there is a rubber sealing ring inside, long time exposure will affect the sealing performance of rubber. Both metal and rubber sealed roller drill bits must be placed in a cool and dry place. Compound seal is a kind of rubber seal, also need the same treatment