FI98649C - A method for drilling a hole and an arrangement for carrying out the method - Google Patents

Description

Λ 98649

METHOD FOR DRILLING A HOLE AND ARRANGEMENT FOR IMPLEMENTING THE METHOD

The invention relates to a method of drilling a hole, in which, in connection with drilling, a protective tube is drawn into the hole by means of a blade arrangement and to an arrangement between the protective tube and the blade assembly.

In rock and earth hole drilling, it is customary to pull a protective pipe into the hole during drilling to prevent the hole from collapsing, at least in the hole portion of the soft soil. The protective tube is pulled by various shoulder arrangements that allow the drill to rotate and the protective tube to be non-rotating as the combination advances in the borehole. In addition, it is known that a certain axial clearance is provided for the drilling device in the shoulder system.

Especially in pile hole drilling, the need has arisen to leave a protective pipe during drilling in the hole at the boundary where the rock begins. In rock drilling, a protective pipe is not necessary. The protective tube has been able to be left in the middle of the drilling in the hole by pulling the middle part of the two-part blade out of the hole so that the ring blade drilling the outer diameter of the hole is also left in the hole with the protective tube. Drilling has been continued by replacing the second, smaller center blade to continue drilling alone, with the extension hole then becoming smaller in diameter.

Finnish application 945852 presents a solution where the protective tube can be left in the hole during drilling without changing the middle cylindrical blade. In this case, too, the ring blade drilling the outer hole diameter is left in place with the protective tube and is continued alone with the same center blade.

^ In both cases, the hole diameter decreases substantially when the drilling is continued only with the center blade. In addition, the annular steel left in the hole must be expensive to manufacture because grooves and shoulders must be formed to connect it to the end of the protective tube so that it can rotate relative to the protective tube and also have limited axial movement relative to the protective tube.

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The solution according to the invention avoids these problems and the invention is characterized by what is stated in the appended claims.

The invention provides a new connection solution between the protective tube and the blade, with which the pulling of the protective tube into the hole can be stopped at any point. The blade or blades drilling the hole continue from this, and the diameter of the drilled hole does not decrease due to leaving the protective tube. The invention achieves a great advantage in pile drilling when the rock section is almost the same diameter as the conduit section. The ring blade is left at the bottom of the hole When the drills are pulled out of the hole, so it does not form a narrowing of the hole at the end of the protective tube as in previous solutions where the ring blade also had to be left at the end of the protective tube.

In the following, the invention will be explained with reference to the accompanying drawing, in which

Figure 1 shows a blade arrangement in which a protective tube is pulled into a hole during drilling.

Figure 2 shows the blade assembly from which the protective tube The pulling shoulder has been removed to leave the protective tube in the hole.

Figure 3 shows a detachable shoulder in a ring blade.

In Fig. 1, the blade arrangement is a ring blade 2 arranged by hitting the central part of the hole and twisting it with a detachable bayonet connection. The blade 1 has a shoulder 8 which transmits impacts to the ring blade. At the end of the protective tube (3), a ring 4 is welded on the inside, which forms a shoulder between the blade 2 and the shoulder ring 5 so that the protective tube follows the blade assembly. The shoulder ring 5 is detachable and preferably also lockable and openable on the surface of the blade 1 with a rotatable bayonet connection.

The rinsing is arranged by double piping through the center of the blade 1, whereby the blade 1 contains bores for guiding the rinsing agent to and in front of the ring blade 2 and in front of the blade 1.

The rinsing agent containing drilling debris is led inside the blade 1 along the innermost tube to the rear. The rinsing agent can also be led at the shoulder 8 to the 98649 3 Λ connection pulling the protective tube 3. A rinsing cycle in the opposite direction is also possible. Leaving the protective tube in the middle of drilling has no effect on the flushing cycle shown in Figures 1, 2. The rinsing agent cannot escape from the front of the blade assembly backwards more than before, because the drilling conditions on the drilling surface remain the same.

When the drill bit assembly takes place in only one direction of rotation of the direction of the arrow in Figure, the two parts 2 and 5 are closed to the blade 1 and the protective tube 3 in the following way.

When the pulling of the protective tube is stopped, the blade assembly is rotated in the other direction for some time, whereby the shoulder ring 5 detaches from behind the platforms 6 and the protective tube is also left behind. The ring blade 2 also rotates on the platforms 9, but it does not, of course, come loose due to the shoulder 8. After some time, the direction of rotation can be changed back to normal. Drilling continues with drill bits 1 and 2 and the hole diameter is also maintained.

Figure 2 shows a situation where the protective tube 3 and the ring 5 have remained in the hole and the blade assembly 1,2 continues alone. When the flushing is an inverse flushing with the inlet and outflow currents being conducted coaxially inside the blade 1 and further using pipelines up to the mouth of the hole, the transport of drilling waste is ensured even with a smaller flow, because the flow rate remains high in small diameter pipes.

When the desired hole depth is reached, the ring blade 2 is unscrewed by reversing the blade 1, the arrow in Fig. 2.

The blade 1 and the drilling rigs can be pulled out of the hole. At the shoulder ring 5, a rotational movement can be made so that it settles into the bayonet and leaves the hole without turning on the way.

'The hole becomes narrower in terms of "light aperture" than in previous solutions, because the blade 2 does not rest on the end of the protective tube in the hole at the protective tube. A larger diameter pile can be placed in the hole, for example as one application example.

Figure 3 shows another version in which a bayonet connection is formed around the shoulder ring 5 'around the ring blade 2'.

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The solution works in other respects as in the example case of Figure 1.

As an alternative, a detachable shoulder, such as a detachable shoulder corresponding to the annular shoulder 4, can be connected to the protective tube 3, e.g. Correspondingly, this opens by rotating the blade assembly in the opposite direction, in which case the protective tube alone is left in the hole at this stage. However, the solution is less suitable compared to the first embodiment.

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Claims (7)

A method for drilling a shark using a rotating or rotating and striking tool (1,2), in which method a protective tube (3) is pulled at the bore into the hole by means of the tile egg assembly (2.5) and and / or the protective tube belonging to the tensioning tube, as well as the lugs (4), characterized in that the pulling of the protective tube (3) is terminated to a desired depth by releasing either the shoulder (5) from the egg assembly (1,2) that pulls the protective tube (3) or by releasing the corresponding drawbar from the guard tube (3), as well as the shoulder (4) for example. by rotating the egg assembly (1,2) to the opposite direction, after which drilling is continued with the aid of the egg assembly. 2. A method according to claim 1 using an egg assembly having a separate heel central portion of the drilling cylinder edge (1) and the outer diameter of the drill bit boring ring (2) which are mutually loaded to rotate or rotate each other during drilling. hence, when the drilling device and the egg assembly are pulled out from the heel, the ring edge (2) is left in the heel for e.g. by turning the inner edge (1) in the opposite direction with respect to the rotation during drilling to release mutual reading between the edges (1) and (2). 98649 7 λ 3. A method according to claims 1 and 2, characterized in that the released ring guide (5) is withdrawn from the heel after drilling either by means of the edge (1) as the protective tube remains in the heel or reddened by the protective tube when the protective tube pulled away from the heel. 4. Composition between a protective tube (3) and an egg assembly (1,2) in a drill assembly, the egg assembly of which has been adapted to pull the protective tube into the heel during drilling, most compatible with the aid of an impact device (4,5), by means of which axial movement between the guard tube and the egg assembly is restricted during drilling, characterized in that at least one of said axial movement limiting shoulder (4), (5) can be released in the borehole either from the guard tube (3) or from the edge (1) ) or (2) in the egg assembly for discarding the protective tube in the heel and for continuing the drilling further without the protective tube. 5. A composition according to claim 4, characterized in that the release shoulder (4), (5) can be read and opened with a rotary movement from the edge (1) or (2) of the egg assembly or from the protective tube (3). 6. Composition according to claims 4 and 5, characterized in that the protective tube (3) has an abutment ring (4) inset and the release abutment (5) is adapted to the surface of the cylinder edge (1) in the egg assembly or to the surface of an annulus. (2 ') which has been releasably fitted to the surface of the cylinder edge. Composition according to any of the preceding claims 1-6, characterized in that the at least the return channel of the flushing medium which is advanced to the egg composition is guided through the center of the egg composition.