The action and fixing method of water hole of cone bit
Bit water hole, make full use of the hydraulic power of the bit, so that high-speed liquid directly shot to the bottom of the well, fully remove the bottom of the well debris, improve the drilling efficiency of the important organ
Bit water hole is an important organ in drilling to make full use of the hydraulic power of the bit and shoot the high-speed liquid directly to the bottom of the well, fully remove the bottom rock cuttings and improve the drilling efficiency. It is mainly composed of nozzle, clamping spring and sealing ring.
Jet drill bits, which are suitable for jet drilling, should be considered in the following aspects:
The flow passage in the drill body should minimize the resistance of mud flow.
Nozzle shape should have good jet characteristics (large flow coefficient, long isokinetic core);
Nozzle can be selected or replaced according to hydraulic design requirements;
Hole arrangement (jet direction, hole location, number) should facilitate cuttings removal.
Jet drills have nozzles made of hard alloy at the water hole. The nozzle should be easy to install and disassemble, because the nozzle suitable for the size is selected according to the situation at that time before use. After the bit is working, the nozzle can be removed and reused. The nozzle and the drill should be sealed, so as not to puncture the drill body when mud flows through the gap and make the nozzle fall into the well.
There are several ways to fix the nozzle:
One is to clamp the nozzle on the bit body with a spring retaining ring and seal radial with an O-ring;
The other is to use the pressure cap to fix the nozzle on the drill body (in the water hole of the drill body, there is an internal thread, with o-ring for end seal;
The last one is sealed with an O-ring, and there is a ring groove in the outer circle of the nozzle and the water hole of the drill body. After the water hole is installed, a special metal wire is inserted and the nozzle is stuck on the drill body.
Table 5 Installation size of nozzle and diameter of water hole
Bit diameter Nozzle diameter assembly length
The hole diameter
mm
inmm
Basic dimensions
mm
Limit deviation
mm
Basic dimensions
mm
Limit deviation
mm
3 1/2-5 1/2 88.9-139.7 20.3
0
0.13
17.5
0
0.30
5 5/8-7 3/8 142.9-187.3 23.6 19.0
7 1/2-8 1/4 190.5-209.6 29.8 21.0
8 3/8-14 5/8 212.7-371.5 33.0
0
0.16
27.0
14 3/4 acuity 374.6 or higher
Note 1: Assembly length refers to the length from the nozzle inlet end to the inlet side of the baffle groove. Note 3: If the drill diameter required by the user is not within the scope of this table, the installation size of the nozzle and the diameter of the water hole can be determined by the user and the manufacturer through negotiation.