FI130193B - Drilling device for drilling a hole in the ground - Google Patents

Abstract

The invention concerns a drilling device (100) for drilling a borehole (22) in the soil (102), which drilling device (100) comprises a multi-part blade (5,9), an impact device (14), a rotating device (50), a first flow channel, a protective tube (3) and an arrangement ( 24) for pulling the protective pipe (3) into the borehole, where the pilot bit (9) and expansion means (5) belong to the bit (5,9), the pilot bit (9) comprising - the bit surface (12), - the flushing channel (4), - at least one return channel (1 ), - at least one blade flushing channel (10), where the combined cross-sectional area of the return channel (1) or return channels (1) is greater than the combined cross-sectional area of the blade rinsing channel (10) or blade rinsing channels (10), and - at least one outlet channel (7), which in the direction of flow is expanding in its cross-sectional area from the blade surface (12) towards the inner space (20) of the protective tube (3), and the depth of the outlet channel (7) is increasing in the width direction of the outlet channel (7) in the opposite direction to the direction of rotation of the blade (5,9), and the expansion means (5) extend in the longitudinal direction of the blade (5,9) to the front of the pilot blade (9) in the drilling direction, in which case the end of the blade flushing channel (10) on the face of the pilot blade (9) is in the radial direction of the blade (5,9) between the pilot blade (9) and the expansion means (5).

Description

DRILL DEVICE FOR DRILLING DRILL HOLES IN THE GROUND

The subject of the invention is a drilling device for drilling a borehole into the ground, which drilling device comprises a multi-part blade, an impact device connected to the blade to give the blade impact movement, a rotation device to rotate the blade, a first flow channel connected to the impact device to conduct a pressurized working air flow to the impact device to use the impact device, a protective tube including the front part and an inner space adapted to pull drilling in connection with the drilled hole and an arrangement between the front part of the protective pipe and the bit for pulling the protective pipe into the drill hole behind the bit via an arrangement, where the bit includes - a pilot bit and expansion means, if the pilot bit includes the bit surface, - a flushing channel formed in the pilot bit to lead the flushing air flow from the impact device to said bit, - at least one return channel adapted to the pilot bit's flushing channel and between the inner space of the protective tube in order to direct the flushing air flow of the part directly to the inner space of the protective tube, where the return channel branches off from the flushing channel, - at least one blade flushing channel fitted between the pilot blade's flushing channel and the blade surface of the pilot blade,

O 25 for directing the flushing air flow to the blade surface to flush the blade surface ro, where the combined cross-sectional area of the return channel or return channels is greater than the combined cross-sectional area of the blade rinsing channel = or blade rinsing channels, and

N - outlet channel fitted between the blade surface of the pilot blade and the inner space of the io 30 protective tube to conduct compressed air flow

N into the interior of the protective tube, which outlet channel is the blade ccircular

N parallel to the misaxis and arranged in the direction of flow to expand in cross-sectional area as it goes from the blade surface towards the inner space of the protective tube, where the discharge channel has the length of the blade

parallel edges, the radial depth of the blade and the width between the edges, and the depth of the discharge channel is increasing in the direction of the width of the discharge channel, going in the direction opposite to the direction of rotation of the blade, in order to facilitate the transfer of drilling waste.

The problem with submersible drilling equipment that works with air and at the same time pipes the borehole has been organizing the flushing in such a way that the air pressure shocks cannot cause harm to old piles in the ground or other structures there. Disadvantages caused by compressed air are, for example, such that the compressed air washes too much material out of the drilled borehole, thus causing dangerous subsidence or even complete collapse.

The level of technology is known from the applicant's own previous publication FI 126918

B, where as a solution to the aforementioned problem exhaust ducts extending backwards from the pilot blade into the tube are used, to which the main part of the air flow intended for rinsing is led, with the blade rinsing ducts leading to the blade surface having a smaller total cross-sectional area than the airflow return ducts led directly back into the protective tube. However, the problem with such a structure is that — the drilling waste released from the soil blocks the protective pipe inwards

O 25 drilling waste removal channels, which allows the pressure against the soil to increase. The problem gets worse as the diameter of the pilot blade increases.

Tr a ~~ As the drilling diameter increases, a large-diameter io 30 drill rod is used to raise the air flow rate to such a level,

N that it can lift the drilling waste up from the borehole. If

The drilled rock pieces are too large, they make it difficult to rotate the drill rod, causing additional friction between the drill rod and the protective pipe to be installed. Especially if the air speed is not able to lift the pieces out of the drill hole at all, the rotation will stop completely and interrupt the entire drilling operation. For this reason, the soy groove, i.e. the outlet channel, must be made in such a way that only a stone of a certain size can go up inside the protective pipe.

The material that gets inside the protective pipe is always as large as it is possible to pass through the outlet channel.

The purpose of the invention is to provide a drilling device that works more efficiently than state-of-the-art drilling devices, in which the clogging of the discharge channels has been reduced. The characteristic features of this invention are evident from the attached patent claim 1.

The purpose of the drilling device according to the invention can be achieved with a drilling device that includes a multi-part blade, an impact device connected to the blade to give impact movement to the blade, a rotation device for rotating the blade, a first flow channel connected to the impact device to lead pressurized working air flow to the impact device to use the impact device, a protective tube including the front part and the inner space adapted to be pulled into the drill hole during drilling and an arrangement between the front part of the casing and the bit for pulling the casing into the borehole behind the bit via the arrangement.

The blade includes a pilot blade and expansion means, the pilot blade — including the blade surface, the flushing channel formed by the pilot

O 25 to direct the flushing air flow from the impact device to the said blade, with the flushing channel branching into a return channel, and at least one return channel fitted to the pilot blade = to direct part of the flushing air flow directly to the protective tube

N to the interior. The return channel branches off from the flushing channel. In addition, the io 30 blade includes a blade rinsing channel fitted to the pilot blade

N between the flushing channel and the blade surface of the pilot blade

N for directing the flushing air flow to the blade surface for flushing the blade surface, where the combined cross-sectional area of the return channel or return channels is greater than the combined cross-sectional area of the blade flushing channel or blade flushing channels, and at least one outlet channel fitted between the blade surface of the pilot blade and the inner space of the protective tube to lead the compressed air flow to the inner space of the protective tube. The outlet channel is parallel to the axis of rotation of the blade and is adapted to expand in cross-sectional area in the direction of flow, going from the blade surface towards the inner space of the protective tube, where the outlet channel has the longitudinal edges of the blade, the depth in the radial direction of the blade and the width between the edges, and the depth of the outlet channel increases in the direction of the width of the outlet channel in the direction opposite to the direction of rotation of the blade to facilitate the transfer of drilling waste. The expansion means extend in the lengthwise direction of the blade to the front side of the pilot blade in the drilling direction, whereby the end of the blade flushing channel on the face of the pilot blade is in the radial direction of the blade between the pilot blade and the expansion means, essentially preventing the pressure effect of the flushing flow on the drill hole in the transverse direction of the pilot blade.

According to the invention, the removal channel is made inclined, so that the rotational moment cannot brake the passage process of the object through the rinsing channel, but rather helps it to be washed away with the air. If the discharge channel were to contract in the direction of rotation, the rotational torque would start to brake the movement of the piece, so the air would not be able to flush the piece from the discharge channel and behind — the new pieces coming would get stuck behind the ones in front,

O 25 even though they would have already been ground down. The arrangement according to the invention ensures that only suitable pieces of rock 0 are flushed through the blade so that they do not brake, = and cannot get stuck, preventing other smaller drilling waste

N particles and other rock rubble washed up from the borehole. io 30 The discharge channel expands from the face of the pilot blade to the back of the blade,

N, when the flushing flow can be continuously reduced

N to the pressure plane from the pilot blade backwards. When the expansion means extend beyond the face of the pilot blade, the pressure effect of the flushing flow is directed in the lateral direction of the blade to the expansion

lines and cannot expand the drill hole laterally.

In this case, the drilling device is adapted to remove mainly soil material that penetrates into the closed area of the extraction channel between the pilot bit and the expansion means. 5

In the drilling device according to the invention, at least one discharge channel growing in the direction opposite to the direction of rotation of the blade and in the direction of flow towards the inner space of the protective tube enables efficient removal of drilling waste from the blade area. At the same time, the pressure on the soil remains low when the combined cross-sectional area of the return channel or return channels directed behind the blade inside the protective tube is larger than the combined cross-sectional area of the blade flushing channel or blade flushing channels directed towards the blade surface. In this case, the narrow blade flushing channel causes sufficient back pressure so that the flushing air of the drilling rig turns to the return channel of the blade and the flushing of the drilling rig inside the protective tube already works without the back pressure generated from the soil. In the drilling rig, the outlet channel growing in the opposite direction to the direction of rotation of the blade enables solid particles in the drilling waste to move as the blade rotates in the outlet channel towards the widest edge of the outlet channel, where they can move freely in the expanding outlet channel towards the interior of the protective pipe.

O 25 There are preferably 2 to 8 return channels. In this case, the blade is easier to balance and a sufficiently large return flow 0 is obtained inside the protective tube. x a ~~ Advantageously, there are 2 to 8 blade rinsing channels. In this case, rinsing the blade surface of the io 30 blade produces a symmetrical one.

S

Advantageously, there are 2 to 8 exhaust ducts. In this case, the continuation of each blade rinsing channel can be a discharge channel and a blade rinsing channel, in which case the rinsing is symmetrical.

Preferably, the return channel is fitted between the flushing channel of the pilot blade and the inner space of the protective tube. In this context, when talking about the protective pipe, it should be understood that the welding shoe welded to the protective pipe or the ring bit connected to the protective pipe forms part of the protective pipe, in the sense that the protective pipe and the welding shoe or the protective pipe and the ring blade together delimit the interior space into which the drilling waste and pressurized flushing flow are led.

Advantageously, the outlet channel is adapted as an extension of the blade rinsing channel. This means that the compressed air flow that washes the blade surface coming from the blade rinsing channel to the blade surface is led along the exhaust channel into the inner space of the protective tube.

Preferably, the depth of each outlet channel increases by 100 to 150% in the opposite direction to the drilling direction in the width direction of the outlet channel. In this case, the outlet channel is large enough so that even the largest pieces of solid matter in the drilling waste can be led into the protective pipe.

Advantageously, the depth of each outlet channel is increasing along the entire length of the outlet channel in the direction of the rotation axis of the blade. In this case — there is no back pressure in the outlet channel, which would make it difficult

O 25 removal of drilling waste and would cause 3 stress on the soil.

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= Advantageously, the return channel and the blade rinsing channel are matched

N to branch off from the flushing channel at essentially the same point. io 30 In this case, the smaller cross-sectional area of the blade rinsing channel

The back pressure exerted by N controls the compressed air used for rinsing

N into the return channel and into the protective pipe.

Advantageously, the flushing channel has an end wall to which the flushing

the channel ends in the pilot blade, at the end wall of which the return channel and the blade flushing channel are connected to the flushing channel.

The end wall directs the flow even more efficiently to the return channel.

According to one form of application, the discharge channel includes a straight part and an expanding part, and the discharge channel is connected to one return channel by the expanding part of the discharge channel. The discharge channel connecting to the expanding part captures the flow of drilling waste in the discharge channel, enhancing the removal of drilling waste.

According to one embodiment, the expanding part is uniformly expanding. In this case, it is simple to prepare.

Preferably, the diameter of the pilot bit at the outlet channel decreases uniformly in the opposite direction to the drilling direction of the blade at the point where the return channel joins the outlet channel.

In other words, the outlet channel grows towards the center of the pilot bit while going in the opposite direction to the drilling direction at the point where the return channel joins the outlet channel. In this case, the resistance of the flow in the direction of the return of the flushing flow is small.

According to another form of application, the discharge channel is evenly expanding along the entire length of the discharge channel.

O 25 According to one form of application, the expanding part is adapted to expand 30 — 100% along its length parallel to the rotation axis 0 of the blade of the expanding part.

Tr a ~~ Advantageously, the total cross-sectional area of the return channel or return channels is 20 to 80% larger than the blade rinsing channel

N or the total cross-sectional area of the blade flushing channels.

N In this case, the compressed air flow used for flushing is efficiently directed to the return channel and the compressed air flow to the blade flushing channel is smaller, reducing the effect of expanding the drill hole.

According to one embodiment, the expansion means is a ring blade.

With the help of the ring bit, the drill hole made by the pilot bit can be expanded in front of the protective pipe to be pulled, while the ring bit remains in the drill hole after the drilling is finished.

According to another embodiment, the expansion means is a reamer blade. After drilling, the reamer bit can be removed from the drill hole together with the pilot bit.

Advantageously, the outlet channel is a groove made on the surface of the pilot blade.

In this case, the exhaust duct is easy to prepare and the compressed air passing through the exhaust duct flushes the gap between the blade and the protective tube at the same time.

Advantageously, the arrangement includes a welding shoe for connecting the pipe to the bit in order to pull the protective pipe behind the bit into the drill hole with the help of the welding shoe.

Alternatively, the protective pipe can also be fed into the drill hole using a welding shoe.

Advantageously, the blade rinsing channel opens directly towards the soil. — In this case, the compressed air used for rinsing can be rinsed

O 25 blade surface efficiently. In other words, this means that when the compressed air flow leaves the blade flushing channel 0, it preferably collides directly with the soil of the drill hole and not with a separate = surface belonging to the blade, as in state-of-the-art

In solutions where the pressure on the soil is io 30 reduced by first impinging the compressed air flow on the blade and

N through it to the soil.

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Advantageously, the outlet channel can be expanded in the radial direction of the blade as it goes from the blade surface towards the inner space of the protective tube.

In other words, the discharge channel is deeper in the radial direction of the blade, closer to the protective tube, than in the vicinity of the blade surface.

In connection with the blade surface of the pilot blade, the depth of the discharge channel can be 3 to 15%, preferably 5 to 10% of the length of the discharge channel at the edge of the discharge channel which is the first in the direction of rotation of the blade. In connection with the blade surface of the pilot blade, the depth of the discharge channel can be 15 to 30%, preferably 18 to 25% of the length of the discharge channel at the edge of the discharge channel which is the latter in the direction of rotation of the blade.

The depth of each discharge channel can increase by 100 - 150% in the radial direction of the axis of rotation of the blade in the direction of the width of the discharge channel, when going from the blade surface of the pilot blade to the inner space of the protective tube.

Inside the protective tube, the depth of the discharge channel can be 6 to 25%, preferably 10 to 15% of the length of the discharge channel at the edge of the discharge channel which is the first in the direction of rotation of the blade.

Inside the protective tube, the depth of the discharge channel can be 30 to 50%, preferably 35 to 40% of the length of the discharge channel at the edge of the discharge channel which is the latter in the direction of rotation of the blade.

The purpose of the preferably multi-directional expansion of the discharge channels is to ensure that the passage of the pressurized air flow fed to the blade surface and through it — to the drill hole

O 25 there are no obstacles in this outlet channel, so the compressed air flow flushing the blade surface ro can pass through the drilling waste 0 without expanding the drill hole. x a ~~ Advantageously, the width of the outlet channel is steadily increasing. In this case, io 30 stones coming off the soil can move when the blade rotates

N towards the wider edge of the outlet channel and finally through it

N inside the protective tube.

Alternatively, the width of the outlet channel can also be gradually increasing. In this case, the step must be at the front of the protective pipe.

The invention is described in detail in the following by referring to the accompanying drawings depicting some applications of the invention, in which

Figure 1 shows the entire drilling device according to the invention from the side,

Figure 2 shows the blade and impact device of the drilling device according to the invention as a principle view from the side,

Figure 3 shows a side view of the drill bit of the invention as a cut-away view,

Figure 4 shows the pilot blade of the drill bit, depicted separately from the direction of the blade surface,

Figure 5 shows the pilot bit of the drill bit, viewed separately from the side,

Figure 6a shows the blade according to the first application form of the drilling device, depicted separately from the direction of the blade surface,

Figure 6b shows the blade according to the second application form of the drilling device, depicted separately from the direction of the blade surface,

Figure 7 shows the drill bit with the pilot bit apart — viewed from the side with the welding shoe,

O 25 Figure 8 shows the drill bit axonometrically ro depicted separately, pilot bit separately. 2 = Figure 1 shows the drilling device 100 according to the invention in

N as a woman. Drilling device 100 can be movable, for example io 30, supported on a frame with a track base and a tower, to which the

N drill rig 100 is supported. The 100 blades of the drill 5.9 are rotated

N by means of the rotation device 50 via the drill rod 52. Pressurized flushing air is supplied to the blade 5.9 from compressed air tools 54. The drilling device according to the invention is intended for

for grouting drilling, where a protective pipe 3 is fed after the blade 5,9, which is shown shortened for the sake of simplification in Figure 1. The drill rig's impact equipment, rotation equipment, compressed air equipment and other peripheral equipment can be fully state-of-the-art. When drilling with the drilling device according to the invention, the blade 5.9 rotates non-rotatingly while the protective tube follows behind the blade 5.9.

According to Figure 2, the drilling device 100 according to the invention includes, in accordance with the state of the art, an impact device 14, preferably comprising a piston 56, which strikes and rotates the blade 5,9, which drills a drill hole 22 into the soil 102, pulling the protective pipe 3 behind it.

According to Figure 3, the drilling device 100 comprises a multi-part blade 5, 9, to which the flushing air flow is introduced via the impact device 14 along the first flow channel (not shown). The blade 5,9 preferably includes a pilot blade 9 and expansion means 5. The protective tube 3 brought after the blade 5,9 includes a front part 18, and an inner space 20 is formed inside the protective tube 3 between the protective tube 3 and the stem of the blade 5,9. The protective tube 3 is connected from its front part 18 to the connection of the blade 5,9 by means of an arrangement 24. The fitting 24 is preferably a welding shoe 11, by means of which the protective tube 3 is connected to the outer edge of the pilot blade 9. The welding shoe is a protective pipe to the ground Pulling — shoulder and its use is not necessary if the feeder is capable

O 25, for example, to push the protective tube into the resulting drill hole 3 behind the blade.

S

= The pilot bit 9 belongs to the drilling device 100 according to the invention

N blade surface 12 and flushing channel 4 for conducting the flushing air flow io 30 from the impact device 14 through the first flow channel

N for said blade 5.9. The impact device 14 is preferably immediate

N in connection with the stem of the pilot blade 9. The flushing channel 4 preferably has an end wall 30, in connection with which the flushing channel 4 preferably branches forward to the blade flushing channels 10 leading to the blade surface 12 and away from the blade surface 12 to the return channels 1 leading towards the inner space 20 of the protective tube 3. The return channels 1 are arranged between the flushing channel 4 and the inner space 20 of the protective tube 3 for the flushing airflow of the pilot blade 9 for leading directly into the inner space 20 of the protective tube 3 to flush it. The blade flushing ducts 10 are again adapted to lead the compressed air used for flushing from the flushing duct 4 to the blade surface 12 of the pilot bit 9 in order to rinse the blade surface 12 from drilling waste, which is generated when the pilot bit 9 and the expansion tools 5 rotate in the drill hole 22 while striking. The combined cross-sectional area of the return ducts 1 is larger than the combined cross-sectional area of the blade flushing ducts 10, whereby the blade flushing ducts 10 form a sufficiently large flow resistance to direct the compressed air flow directly along the return ducts 1 into the inner space 20 of the protective pipe 3 to flush it without the back pressure caused by the soil. With this solution, the compressed air flow coming from the flushing channel 4 can be divided so that at least most of the flow turns back along the return channels 1 to the inner space 20 of the protective tube 3 and a smaller part is led to the blade surface 12 of the pilot blade 9 to perform the flushing of the blade surface 12.

Although in connection with the detailed explanation of the invention, there has been talk about the use of several return channels, a blade rinsing channel and a discharge channel, this is only a preferred embodiment of the invention. Will come

O 25 understands that the drilling device according to the invention can also be realized using only one return channel, one blade rinsing channel and one outlet channel. x a ~~ The compressed air flow directed to the blade surface 12 io 30 of the pilot blade 9 through the blade flushing channels 10 is led through the blade flushing channels 10

N along the outlet channels 7 formed as a continuation of the protective pipe 3

N in, preferably using first the radially inclined channel 7.1 of the blade 5,9 to conduct compressed air towards the outer edge of the pilot blade 9 and from there along the straight part 26 belonging to the exhaust channel 7 to the expanding part 8 belonging to the exhaust channel 7. In other words, the exhaust channels 7 are adapted to the pilot blade 9 as an extension of the blade flushing channels 10 in order to conduct compressed air to the protection - into the inner space 20 of the tube 3. The exhaust ducts 7 are adapted to expand in cross-sectional area in the flow direction when going from the blade surface 12 towards the inner space 20 of the protective tube 3. Preferably, the expansion takes place in the radial direction of the axis of rotation of the blade 5,9 as shown in Figure 3. In other words, the closer you are to the protective tube 3, the deeper the outlet channels 7 are.

According to Figure 4, each discharge channel 7 has the radial depth d of the blade 5.9 and the width between the edges 44 belonging to the discharge channel 7 is 1. According to the invention, the depth of each discharge channel 7 is increasing in the direction opposite to the direction of rotation of the blade 5.9 in the direction of the width of the discharge channel 7 to facilitate the transfer of drilling waste. The depth of each outlet channel 7 can increase by 100 — 150% in the direction opposite to the drilling direction in the width direction of the outlet channel 7. In connection with the blade surface 12 of the pilot blade 9, the depth d of the discharge channel 7 can be 3 — 15%, preferably 5 — 10% of the length of the discharge channel 7 1 at the edge of the discharge channel 7 which is first in the direction of rotation of the blade 5.9.

In connection with the blade surface 12 of the pilot blade 9, the depth d of the outlet channel 7 can be 15 to 30%, preferably 18 to 25% of the length 1 of the outlet channel 7 at the edge of the outlet channel 7, which is the edge of the blade 5.9

O 25 in the direction of rotation in the latter. In the auger device according to the invention, the blade 5,9 is rotated so that the shallower edge of the outlet channel 70 meets the soil first and the deeper edge meets the soil last, i.e. the blade rotates clockwise when viewed

N blades from top to bottom. Figure 4 shows the correct direction of rotation 30 with reference number 42.

S

The depth of each outlet channel 7 can increase by 100-150% in the radial direction of the rotation axis of the blade in the width direction of the outlet channel 7 when going from the blade surface 12 of the pilot blade 9 to the inner space of the protective tube 3. Inside the protective tube 3, the depth d of the outlet channel 7 can be 6 to 25%, preferably 10 to 15% of the length of the outlet channel 7 in the edge 44 of the outlet channel 7 which is first in the direction of rotation of the blade 5.9. Inside the protective tube 3, the depth d of the outlet channel 7 can be 30 to 50%, preferably 35 to 40% of the length of the outlet channel 7 in the edge of the outlet channel 7 which is the latter in the direction of rotation of the blade 5.9. The purpose of the preferably multi-directional expansion of the discharge channels 7 is to ensure that there are no obstacles in the discharge channel 7 for the passage of the pressurized air flow fed to the blade surface 12 of the blade 5,9 and through it to the drill hole 22, so that the compressed air flow flushing the blade surface 12 can pass, moving the drilling waste, without expanding the drill hole 22.

Figure 5 shows how the return channels 1 connect to the outlet channel 7 preferably with its expanding part 8 and preferably close to the end of the outlet channel 7 which is in the inner space 20 of the protective tube 3 as shown in Figure 3. In Figure 5, reference number 36 shows the groove for the bayonet locking of the ring blade.

The drilling device according to the invention can be used to drill soil and rock, and the flushing of the drilling device inside the pipe element already works without the back pressure generated from the ground, because the common cross-sectional area of the return channels connected to the flushing channel is larger

O 25 as the common cross-sectional area ro of the flow channels directed from the flushing channel to the blade. The exhaust ducts 7 are formed as shown in figure 0 3 to expand backwards (direction 2), so they do not = try to force the flow of flushing air in the direction of drilling (direction

N 6), whose back pressure formed by the soil 102 must be overcome io 30 to enable flushing, as with conventional drilling rigs

With N systems Elemex and Stable-X. Because the exhaust ducts 7 are

N designed to expand backwards, no harmful air discharges into the soil are possible. Furthermore, due to the structure of the drill's pilot blade, the drill practically only removes material that penetrates the closed area of the discharge channel and thus eliminates the phenomenon of overflushing, which is also called mammothing. Thus, with the drilling device according to the invention, it is possible to drill large piles very close to potentially damaged objects, because pressure shocks are not possible, and the system does not overflush the drill hole.

Preferably, the pilot bit of the drilling device according to the invention has at least two discharge channels, but there can also be three or even four if the diameter of the pilot bit is large.

The number of return channels and blade rinsing channels is preferably the same as the removal channels, i.e. if there are two removal channels, then there are two return channels and two blade rinsing channels.

According to Figures 6a and 6b, in connection with the pilot bit 9, the expansion means 5 can be used as the ring bit 28 according to Figure 6a or the spacer bit 32 according to Figure 6b. These are alternative solutions for the expansion means 5 to be used with the pilot bit 9. When the protective pipe has been drilled into the rock or to the target level, the pilot bit is rotated in the opposite direction direction compared to the direction used during drilling. In this case, the pilot blade 6 is freed from the arrangement by means of the bayonet attachment, which — can also be called a ground shoe, and can be lifted up

O from 25 boreholes. The fitting 24 and the expansion means 5, if the ro expansion means 5 are the ring bit 28 according to figure 6a, remain 0 in the drill hole 22. If the expansion means are according to figure 6b = reamer bit 32, the reamer bit 32 can also be lifted out

N from the borehole at the end of the drilling. on the 30th

N Figure 7 shows the drilling device 100 according to the invention

N pilot blade 9 with the welding shoe 11 that acts as an adapter 24 for securing the protective tube 3. The reference number 34 shows the blade pieces in Figures 3 and 6a to 8, and the reference number 33 shows the recesses of the blade pieces 34, which can be seen in Figures 4 and 5. Figures 5 and 8 show an additional return channel 38, which can be made between the inner space 20 of the protective tube 3 and the flushing channel 4 to enhance the return flow.

The diameter of the rinsing channel 4 can be, for example, 30 mm, in which case the diameter of the blade rinsing channels can be 9 mm. The drilling device according to the invention can be used for drilling ground pipes for the formation of drill piles to a depth of 2 to 100 m, preferably to a depth of 5 to 10 m.

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Claims (15)

PATENT CLAIMS 1. Drilling device (100) for drilling a drill bit (22) in ground (102), which drilling device (100) consists of a multi-part drill (5, 9), an impact device (14) connected to the drill (5, 9) for delivery of an impact movement to the drill (5, 9), a rotation device (50) for rotating the drill (5, 9), a first flow channel connected to the impact device (14) for conducting a working air flow under pressure to said impact device (14) for driving of the impact device (14), a protective tube (3) including a front part (18) and an inner space (20) arranged to be drawn in connection with the drilling to the drill bit (22) being drilled and an arrangement (24) between the protective tube (3) ) front part (18) and the drill (5, 9) to pull the protective pipe (3) to the drill heel (22) after the drill (5, 9) by means of the arrangement (24), where the drill (5, 9) includes a pilot drill (9) ) and expansion devices (5), where the pilot drill (9) includes - a drilling surface (12), - a flushing channel (4) formed in said pilot drill (9) for conducting a flushing air flow from the impact device (14) to said drill (5) , 9). - at least one return channel (1) arranged to the pilot drill (9) for conducting a part of the flushing air flow directly to an inner space (20) of the protective tube (3), and said return channels (1) S 25 branch off from the flushing channel (4), N - at least a drill flushing channel (10) arranged to the N pilot drill (9) between the flushing channel (4) and the pilot drill (9) = drilling surface (12) for conducting part of the flushing air flow to the N drilling surface (12) for flushing the drilling surface (12), where the return channel's o 30 (1) or the combined cross-sectional area of the return channels (1) is N greater than the combined cross-sectional area of the drilling flushing channel (10) or the drilling flushing channels (10), and - at least one exit channel (7) arranged for the pilot drill (9) between the drilling surface (12) and the inner space (20) of the protective tube (3) for conducting compressed air to the inner space (20) of the protective tube (3), which outlet channel (7) is in the direction of the rotation axis of the drill (5, 9) and is arranged to be expanded to its cross-sectional area in the direction of flow from the drilling surface ( 12) towards the inner space (20) of the protective tube (3), where the outlet channel (7) has the edges (44) of the drill (5, 9) in the longitudinal direction, the depth of the drill (5, 9) in the radial direction, the width between said edges (44), and the depth of the outlet channel (7) grows in the width direction of the outlet channel (7) in a direction of rotation opposite to the direction of rotation of the drill (5, 9), to facilitate the movement of the drilling waste, characterized in that the expansion devices (5) extend in the longitudinal direction of the drill (5, 9) to in front of the pilot drill (9) in the drilling direction, whereby the end of the drill flushing channel (10) at the front of the pilot drill (9) is in the radial direction of the drill (5,9) between the pilot drill (9) and the expansion devices (5), which significantly prevents the pressure effect of the flushing flow on the drill heel (22) ) in the transverse direction of the pilot drill (9). 2. Drilling device according to patent claim 1, characterized in that the depth of the outlet channel (7) grows $100 - $150 in the opposite direction to the drilling direction in the width direction of the outlet channel (7). 3. Drilling device according to patent claim 1 or 2, characterized © in that the depth of the outlet channel (7) grows over the entire length of the outlet channel S 25 (7) in the direction of the rotation axis of the drill (5, 9). S N 4. Drilling device according to one of the patent claims 1 - 3, = characterized in that said return channel (1) and drilling flushing channel N (10) are arranged to branch off from the flushing channel (4) at essentially the same place. S 5. Drilling device according to patent claim 4, characterized in that the flushing channel (4) has an end wall (30), at which the flushing channel (4) ends in the pilot drill (9), in connection with which end wall (30) said return channel (1) and drill flushing channel (10) connects to the flushing channel (4). 6. Drilling device according to one of the patent claims 1 - 5, characterized in that the output channel (7) comprises a straight part (26) and an expanding part (8), and to the output channel (7) a mentioned return channel (1) is joined to the output channel (7) ) expanding part (8). 7. Drilling device according to patent claim 6, characterized in that said expanding part (8) expands evenly. 8. Drilling device according to claim 6 or 7, characterized in that said expanding part (8) is arranged to expand 30 - 100% over the length of the expanding part (8) in the direction of the rotation axis of the drill (5, 9). 9. Drilling device according to one of the patent claims 1 - 8, characterized in that the combined cross-sectional area of the return channel (1) or the return channels (1) is 20 - 80% larger than the combined cross-sectional area of the drilling flushing channel (10) or the drilling flushing channels (10). e 10. Drilling device according to one of the patent claims 1 - 9, S 25 characterized in that said expansion devices (5) are an S ring crown (28). N = 11. Drilling device according to one of claims 1 - 9, N characterized in that said expansion device (5) is an arbor drill (32). S 12. Drilling device according to any of the patent claims 1 - 11, characterized in that the diameter of the pilot drill (9) at the outlet channel (7) is uniformly reduced in a direction opposite to the drilling direction of the drill (5, 9) at the point where the return channel (1) joins the outlet channel ( 7). 13. Drilling device according to one of claims 1 - 12, characterized in that the arrangement (24) includes a welding shoe (11) for connecting the protective tube (3) to the drill (5, 9). 14. Drilling device according to any of the patent claims 1 - 13, characterized in that said drilling flushing channel (10) opens directly towards the ground (102). 15. Drilling device according to one of claims 1 - 14, characterized in that said outlet channel (7) is expanded in the radial direction of the drill (5, 9) in the direction from the drilling surface (12) towards the inner space (20) of the protective tube (3). O N O N N <Q N N I Ao a N N 0 O N O N