Reverse Circulation drill rod or drill pipe
Reverse Circulation drilling, or RC drilling, uses rods with inner and outer tubes, the drill cuttings are returned to surface inside the rods. The drilling mechanism is a pneumatic reciprocating piston known as a hammer driving a tungsten-steel drill bit.
The reverse circulation drill rod has four threads which adds to machine operating time. The purpose of the two extra threads is to allow the inner tube to be replaced in the field. It also allows the driller to replace the box tool joint with a new tool joint, without welding and can be done at the site. - We use heat threaded 4130 alloy tool joints; this alloy allows driller to employ a hard facing program without fear of embitterment. We use a micro-alloy midsection (mid-body), ST52V, 90KS1 MIL VLD possessing a superior abrasion resistance. - Our inner tube midsection (mid-body) is a heavy-wall mechanical tube, not a pipe. The inner tube is fixed and won't vibrate under most conditions. The inner tube ends are made from a heat treated alloy and the male end is machine finished after welding for perfect alignment. - The o-ring retainers absorb the percussion forces to eliminate problems arising from the transfer of vibration and torque loads to the outer pipe.
| Reverse circulation drill pipe/Double wall drill pipe/Dual Wall drill pipe |
| Outer tube O/D in |
Inner tube in |
Lerngth m |
Type of thread |
Range of drill in |
| 3 1/2 |
1 1/2 |
3 ~ 6 |
Remet, Metzke, Matrix, others |
4-1/8-4-3/4 |
| 4 |
2 |
3 ~ 6 |
Remet, Metzke, Matrix, others |
4-3/4-5-1/2 |
| 4 1/2 |
2 & 2-1/2 |
3 ~ 6 |
Remet, Metzke, Matrix, others |
5-1/8-6 |
| 6 5/8 |
3 |
3 ~ 6 |
Remet, Metzke, Matrix, others |
7-7/8-15 |
| 10 3/4 |
5 |
3 ~ 6 |
Remet, Metzke, Matrix, others |
Over 15 |
| * Roschen offers reverse circulation drill string components in accordance with the requirements of the customer. Reverse circulation drill pipes available in different model, diameters and length. |
| REVERSE CIRCULATION DRILL ROD SPECIFICATIONS |
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| Type / Thread |
Remet |
Remet |
Remet |
Metzke |
Metzke |
Matrix |
Matrix |
| Rod O.D. |
3 1/2" |
4" |
4 1/2" |
4" |
4 1/2" |
4" |
4 1/2" |
| Outer tube O.D. |
88.9mm |
101.7mm |
114.3mm |
101.7mm |
114.3mm |
101.7mm |
114.3mm |
| Outer tube I.D. |
81.8mm |
94.6mm |
107.2mm |
94.6mm |
107.2mm |
94.6mm |
107.2mm |
| Outer tube WT |
5.3mm |
7.1mm |
7.1mm |
7.1mm |
7.1mm |
7.1mm |
7.1mm |
| Inner tube O.D. |
38.1mm |
50.8mm |
63.5mm |
50.8mm |
63.5mm |
50.8mm |
63.5mm |
| Inner tube I.D. |
32.6mm |
45.3mm |
58mm |
45.3mm |
58mm |
45.3mm |
58mm |
| Inner tube WT |
5.5mm |
5.5mm |
5.5mm |
5.5mm |
5.5mm |
5.5mm |
5.5mm |
| Spanner Flat |
90mm |
90mm |
90mm |
90mm |
90mm |
90mm |
90mm |
| Weight 3.0 m |
77 kg. |
77 kg. |
97 kg. |
77 kg. |
97 kg. |
77 kg. |
97 kg. |
| Weight 6.0 m |
125 kg. |
155 kg. |
172 kg. |
155 kg. |
172 kg. |
155 kg. |
172 kg. |
Reverse circulation is achieved by blowing air down the annulus of the rod, the differential pressure creating air lift of the water and cuttings up the inner tube which is inside each rod. It reaches the deflector box at the top of the drill string then moves through a sample hose which is attached to the top of the cyclone.
The drill cuttings travel around the inside of the cyclone until they fall through an opening at the bottom and are collected in a sample bag. For any drill hole there will be a large number of sample bags, each one marked to record the location and drilling depth that the sample was obtained.
The collected series of sample bag cuttings are later taken for analysis to determine the mineral composition of the drill hole. The analysis results of each individual bag represents the mineral composition at a particular sample point in the drill hole. Geologists can then survey the drilled ground analysis and make decisions about the value of the overall mineral deposit.
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