Arrangement for drilling borehole into ground or rock

Abstract

An arrangement (100) for drilling a borehole into a ground or rock, the arrangement comprising a drill bit (110), which drill bit has a flow-through (110M) channel for guiding the medium to the borehole, a double-walled drilling rod (120) connected to the drill bit, the double-walled drilling rod having a middle passage (120M) in connection to the flow-through channel of the drill bit, the double-walled drill- ing rod further having, around the middle passage, an annular passage (120A), and a blocking device (130) for guiding the medium and the cuttings to the annular passage of the dou- ble-walled drilling rod. A blocking device (130) for an arrangement for drilling a borehole into a ground or rock. A method for drilling a borehole, wherein the method comprises supplying a medium through the rotating device, through the double-walled drilling rod, and through the drill bit to the borehole, and guiding the medium and cut- tings out from the borehole.

Description

[0001]ARRANGEMENT^FOR^DRILLING^BOREHOLE^INTO^GROUND^OR^ROCK FIELD OF THE INVENTION The invention relates to an arrangement for drilling a borehole into a ground or rock, and for removal of cuttings out from the borehole by a medium. BACKGROUND OF THE INVENTION In conventional drilling, there are different kind of arrangements for drilling boreholes, adding pile casings and for removing cuttings formed during drilling. Typically, a drill bit and a hollow drilling rod is being pressed, against a ground or rock, and rotated to form the borehole. For removing cuttings from the borehole during drilling, a medium such as pressurized water or pressurized air is fed through the hollow drilling rod and further through the drill bit to the borehole, from where the medium leads the cuttings out via a channel formed between the borehole and the drilling rod. An arrangement herein is simple, but, however, a di- ameter of the borehole affects significantly to a consumption of the medium needed for leading the cuttings out from the borehole. Thus, the larger is the diameter of the borehole, the higher is the consumption of the medium to achieve a sufficient transportation of the cuttings out from the borehole. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a novel arrangement for drilling a borehole into a ground or rock, and for removal of cuttings out from the borehole by a medium. The invention is characterized by the features of the independent claims. The invention is based on the idea of the arrangement comprising a drill bit for drilling boreholes, the drill bit comprising a flow-through channel for guid- ing the medium to the borehole. Further, the arrangement comprises a double- walled drilling rod connected to the drill bit, the double-walled drilling rod having a middle passage in connection to the flow-through channel of the drill bit, said middle passage allowing the medium to flow to the flow-through channel, the dou- ble-walled drilling rod further having, around the middle passage, an annular pas- sage allowing the medium and the cuttings to flow from the borehole to the annular passage. The arrangement comprises a blocking device for guiding the medium and the cuttings to the annular passage of the double-walled drilling rod. An advantage of the solution is that it provides a simple connection for the medium to be supplied into the borehole and for the medium and the cuttings to be supplied out from the borehole. For example, the arrangement can be con- nected to a rotating device that has a through-hole for supplying the medium, which rotating device is commonly known and widely used in a traditional equip- ment for drilling boreholes. Another advantage of the solution is that a consump- tion of the medium, needed for leading the cuttings out from the borehole, does not increase significantly when large sized boreholes are being drilled. Some embodiments of the invention are disclosed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which Figure 1 shows schematically and partially an arrangement for drilling a borehole, viewed from a side of the arrangement as a partial longitudinal cross- sectional view, Figure 2A shows schematically and partially an arrangement of Figure 1 with a guiding device having a bearing, viewed from a side of the arrangement as a partial longitudinal cross-sectional view, Figure 2B shows schematically a partial transversal cross-sectional view of the arrangement of Figure 2A, Figure 3A shows schematically and partially an arrangement of Figure 1 with a different kind of guiding device having a bearing, viewed from a side of the arrangement as a partial longitudinal cross-sectional view, Figure 3B shows schematically and partially a detail of Figure 3A, Figure 4 shows schematically and partially the arrangement of Figure 1 with a guiding device having a bearing and a lubrication channel, viewed from a side of the arrangement, and Figure 5 shows schematically and partially an arrangement of Figure 4, viewed from a top of the arrangement. For reasons of the clarity, some embodiments of the invention are illus- trated in the figures in a simplified form. In the figures, like reference numerals identify like elements. DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows schematically and partially an arrangement for drilling a borehole, viewed from a side of the arrangement as a partial longitudinal cross- sectional view. Figure 2A shows schematically and partially an arrangement of Fig- ure 1 with a guiding device having a bearing, viewed from a side of the arrangement as a partial longitudinal cross-sectional view. Figure 2B shows schematically a par- tial transversal cross-sectional view of the arrangement of Figure 2A. Figure 3A shows schematically and partially an arrangement of Figure 1 with a different kind of guiding device having a bearing, viewed from a side of the arrangement as a par- tial longitudinal cross-sectional view. Figure 3B shows schematically and partially a detail of Figure 3A. Figure 4 shows schematically and partially the arrangement of Figure 1 with a guiding device having a bearing and a lubrication channel, viewed from a side of the arrangement. Figure 5 shows schematically and partially an ar- rangement of Figure 4, viewed from a top of the arrangement. The arrangement 100 is suitable for drilling a borehole into a ground or rock, and further for inserting piles casing(s) into said borehole. Cuttings are formed during drilling, wherein the cuttings are typically broken bits of solid ma- terial and / or other loose soil to be removed from the borehole. The arrangement 100 comprises a drill bit 110 for drilling boreholes, which drill bit 110 has a flow-through channel 110M for guiding the medium to the borehole. The arrangement 100 further comprises a double-walled drilling rod 120 connected to the drill bit 110, the double-walled drilling rod 120 having a middle passage 120M in connection to the flow-through channel 110M of the drill bit 110 allowing the medium to flow to said flow-through channel 110M, the arrangement further having, around the middle passage 120M, an annular passage 120A allow- ing the medium and the cuttings to flow from the borehole to the annular passage 120A, the annular passage 120A being implemented by the annular space remain- ing between the walls of the double-walled structure of the drilling rod 120. The arrangement 100 further comprises a blocking device 130 for guiding the medium and the cuttings to the annular passage 120A of the drilling rod 120. The blocking device 130 splits the borehole to two sections by forming a bottom space 130B for guiding the medium and the cuttings in a controlled way to the annular passage 120A of the drilling rod 120, and by forming an upper space 130U, which is a space locating above the blocking device 130 and further locating between an inner wall of the borehole / pile casing and the arrangement 100. For supplying and / or producing the medium, there is a medium supply 20 such as a compressor, which medium supply locates on the ground. The medium herein is a pressurized medium such as the compressed / pressurized air, and it is used for removing cuttings out from a bottom of the borehole, thus, out from the bottom space 130B, but, in addition, the medium may be used for producing energy to the drill bit 110 for drilling the borehole. The medium supply 20 such as the compressor comprises a conduit 22 connected to the drilling rod 120, i.e., the dou- ble-walled drilling rod 120, for leading the medium, i.e., the compressed air, to the middle passage 120M of the drilling rod 120. The conduit 22 between the medium supply 20 and the middle passage 120M of the double-walled drilling rod 120 is arranged via the rotating device 30. Further, the medium may be used also to maintain a bearing 210 of the blocking device 130, i.e., the medium may be used to keep a bearing 210 of the blocking device 130 free from impurities, which medium is configured to flow through the bearing for removing impurities therein, and which arrangement is il- lustrated for example in Figures 4 and 5. The compressed air typically comprises some oil, i.e., oil / lubricating particles, to lubricate devices such as the down-the- hole hammer 116 (DTH hammer) that uses the compressed air as an energy source. The oil in the compressed air also lubricates said bearing 210 of the block- ing device 130. On the ground, thus above the borehole to be drilled, the arrangement 100 may comprise a drilling rig for executing operations such as adding, removing, displacing, connecting and / or maintaining components such as drill bit(s), drilling rod(s), pile(s), and so on, for example, which drilling rig is not shown in the Figures for sake of the clarity. Typically, the drilling rig is a mobile drilling rig configured to move and to be supported onto the ground for a specified period, but the drilling rig may also be a stationary structure erected onto the ground for a specified pe- riod. Further, on the ground, thus above the borehole to be drilled, the ar- rangement 100 may comprise a hoisting device configured to push the drilling rod and / or configured to prevent movement of the drilling rod and the drill bit in an axial direction of the drilling rod and the drill bit, thus in an axial direction of the borehole. The hoisting device may be used for pushing the pile casing(s) into / in the borehole. The hoisting device is not shown in the Figures for sake of the clarity. The hoisting device may be attached to the drilling rig. Further, on the ground, thus above the borehole to be drilled, the ar- rangement may comprise a rotating device 30 such as a top drive or a rotary head, that is coupled to the drilling rod. The rotating device 30 is coupled to a top of the double-walled drilling rod 120. The rotating device 30 may also be attached to the drilling rig or the hoisting device. Thus, the rotating device 30 may be coupled be- tween the drilling rod 120 and the drilling rig. Said rotating device 30 thus locates above the borehole and / or the ground. The rotating device is configured to rotate the drilling rod 120 and the drill bit 110 for example electrically or hydraulically. The attachment between the rotating device and the drilling rod may be a screw joint, API joint, HEX joint, or bolt coupling, for example. Further, the rotating device 30 has a through-hole allowing the double- walled drilling rod 120 and the medium supply 20 to be connected / coupled to each other. In more detail, said through-hole allows the middle passage 120M of the drilling rod 120 and the conduit 22 of the medium supply 20 to be connected / cou- pled to each other. Said through-hole of the rotating device 30 may allow the dou- ble-walled drilling rod to be connected through said through-hole. Said through- hole of the rotating device 30 may allow the conduit 22 of the medium supply 20 to be connected through said through-hole. The through-hole of the rotating device 30 herein is a traditional technology. Thus, traditionally, the through-hole of the rotating device 30 is used to couple a single-walled drilling rod and the medium supply. For now, regarding to a solution, said solution herein allows to use a tradi- tional drilling equipment for coupling the double-walled drilling rod 120 and the medium supply. Said rotating device 30 provides a simple coupling and a route for supplying the medium to the drill bit for drilling the borehole. As mentioned above, the drill bit 110 may be rotated by the rotating device 30 that locates above the borehole and / or the ground, but alternatively or in addition, the drill bit 110 may be rotated by a rotating device that is coupled or integrated to the drill bit 110. Said rotating device is configured to receive energy from the medium which is transmitted to the rotation of the drill bit 110. Further, for drilling the borehole, the drill bit 110 may be directed to the percussive movement / motion by a percussion device 116 that is coupled the drill bit. The percussion device 116 is configured to receive energy from the medium which is transmitted to the percussive movement / motion of the drill bit. After the medium is used to produce the percussive movement, the medium is further used for supplying the medium and the cuttings away from the borehole. The percussion device herein is a down-the-hole hammer 116. According to an embodiment, the percussion device 116 may locate on the ground, thus above the borehole, wherein the percussion device is coupled to the drilling rod 120 and / or to the rotating de- vice 30. The percussion device 116 herein is a top hammer. The arrangement 100 of the Figures comprises a down-the-hole hammer 116 (DTH hammer 116) for producing the percussive motion during drill- ing the borehole. The DTH hammer 116 is couped to the drill bit 110 and to the double-walled drilling rod 120. Illustrated in another words, the DTH hammer 116 is coupled between the drill bit 110 and the double-walled drilling rod 120. The DTH hammer 116 has a longitudinal direction, which is a depth direction of the borehole. The DTH hammer 116 is configured to receive the medium and to put the drill bit 110 in percussion / percussive movement. The DTH hammer 116 has essen- tial parts such as valves, a piston, channels, springs and so on to transform received energy to the movement of the drill bit 110. The medium typically comprises oil particles for maintaining parts of the DTH hammer 116. Further, the DTH hammer 116 has a channel 116M for receiving the me- dium from the double-walled drilling rod 120 and allowing the medium to pass therethrough, wherein the DTH hammer 116 is configured to use the passing me- dium for producing the percussive movement of the drill bit 110. The arrangement 100 of the Figures comprises a coupler 150, i.e., a cou- pling 150, for coupling the down-the-hole hammer 116 and the drilling rod 120. The coupler 150 comprises a socket 152 at the end of the drilling rod 120 and an extrusion portion 154 at the end of the DTH hammer 116, wherein said socket and extrusion portion correspond to each other. Section of the socket 152 and the ex- trusion portion 154 may have a shape of square, hex, torx or such, for example. The coupling further comprises a pin 156 and a hole thereof in radial direction of the coupler 150 for removably locking the coupler 150. The coupler 150 may be cou- pled to the drill bit 110 if the DTH hammer 116 is not used. The coupler 150 has a passage for supplying the medium from the drilling rod to the down-the-hole ham- mer 116 or to the drill bit 110. The coupler 150 transmits the rotational movement from the drilling rod 120 to the DTH hammer 116. According to an embodiment, the coupler 150 is an internal threading at the end of the drilling rod 120 and an external threading at the end of the DTH hammer 116 or at the end of the drill bit 110, which said internal and external threading correspond to each other. The cou- pler 150 may be called an API coupler, for example. According to an embodiment, which the coupler 150 is an external threading at the end of the drilling rod 120 and an internal threading at the end of the DTH hammer 116 or at the end of the drill bit 110, which said internal and external threading correspond to each other. The coupler 150 may be called an API coupler for example. The drill bit 110 of the Figures is coupled to the down-the-hole hammer 116. The drill bit 110 comprises a shank 118 for the drill bit 110 being coupled to the down-the-hole hammer 116. Alternatively, if the-down-the-hole hammer 116 is not used, the drill bit 110 may be coupled directly to the drilling rod 120. The drill bit 110, and in more detail, the shank 118 has a screw connection or a spline connection for coupling the drill bit 110 and the DTH-hammer 116 to each other, or for coupling the drill bit 110 and the drilling rod 120. The drill bit 110 of the Figures is thus used for drilling the borehole. The drill bit 110 comprises a drill head 114, i.e., a drill crown, comprising a body and cutting elements thereof. The cutting elements such as rolling cutter bits and / or fixed cutter bits locates at a front 114F of the drill head 114, which front 114F is intended to be towards to the bottom of the borehole during drilling, and which cutter bits are not shown in the Figures for sake of the clarity. There may be bear- ings for the cutting elements which may need lubrication. The drill head 114 may have grooves at side(s) of the drill bit, wherein the grooves allow the medium and the cuttings to pass through. The drill bit 110 of the Figures may be used for inserting the pile deeper into to the borehole during drilling. For pushing the pile casing deeper into / in the borehole, the drill bit 110, or in more detail, the body of the drill bit 110 comprises an extrusion portion(s) at a side of the drill bit 110, which extrusion portion(s) are configured to correspond to the inner wall of the pile casing and / or a bottom plate of the pile casing. Further, during the borehole is being drilled, the extrusion por- tion(s) of the drill bit 110 pushes the pile casing deeper into / in the borehole. The extrusion portions may be integrated to the drill head 114, and in more detail, to the body of the drill head 114. The extrusion portions are not shown in the Figures for sake of the clarity. The drill bit 110 of the Figures further comprises a flow-through chan- nel 110M allowing the medium to flow below the drill bit 110 to the bottom of the borehole and / or to sides of the drill bit 110. The flow-through channel 110M is a channel, or a hole, allowing the medium to flow through the drill bit 110. The me- dium herein is received from the down-the-hole hammer 116, and in more detail, the medium is received from the channel 116M of the down-the-hole hammer 116. A purpose of the medium is to supply the cuttings and the loose soil away from the borehole. A purpose of the medium is to flush the cuttings away from around of the drill bit 110. The flow-through channel 110M of the drill bit 110 is connected to the channel 116M of the down-the-hole hammer 116. The flow-through channel 110M of the drill bit 110 is connected to the middle passage 120M of the double-walled drilling rod 120, which connection is implemented via the down-the hole hammer 116. Thus, the connection allows the medium to flow, from said middle passage 120M of the drilling rod 120 to the channel 116M of the down-the-hole hammer 116, and further from said channel 116M of the down-the-hole hammer 116 to the flow-through channel 110M of the drill bit 110, and out from the flow-through channel 110M through / to the front 114F or through / to the sides of the drill bit 110, thus to the bottom space 130B. The drilling rod 120 of Figures is a double-walled drilling rod 120. The drilling rod 120 has a middle axis MA’ around which the drilling rod 120 is config- ured to be rotated. The double-walled drilling rod 120 has the middle passage 120M that is connected, via the channel 116M of the down-the-hole hammer 116, to the flow-through channel 110M of the drill bit 110. The middle passage 120M of the drilling rod 120 allows the medium to flow into the flow-through channel 110M of the drill bit 110. The double-walled drilling rod 120 also has the annular passage 120A around the middle passage 120M, which annular passage 120A is in connec- tion to the bottom space 130B. The annular passage 120A of the drilling rod 120 allows the medium and the cuttings to flow, from the bottom space 130B to the annular passage 120A of the drilling rod 120 and through said annular passage 120A of the drilling rod 120. Thus, the annular passage 120A allows the medium and the cuttings to be supplied above the borehole. The drilling rod 120, i.e., the double-walled drilling rod 120, has a struc- ture as follows. The drilling rod 120 comprises a first pipe 126, made of steel for example, the first pipe 126 providing said middle passage 120M of the drilling rod 120. The drilling rod comprises a second pipe 128, made of steel for example, that encloses at least partially the first pipe 126, and in more detail, the second pipe 128 encloses at least partially sides of the first pipe 126. A space having an annular cross-section between the first pipe and the second pipe provides said annular pas- sage 120A of the drilling rod 120. The first pipe 126 and the second pipe 128 are arranged together by connecting pieces 129 such as steel plates that are attached between said pipes, said pipes being arranged symmetrically thereof, thus locating symmetrically around the common middle axis MA’ of the drilling rod 120. The connecting pieces 129 may locate at end(s) of the drilling rod 120. The connecting pieces 129 may extend over the end of the drilling rod 120 for being fitted to a following drilling rod 120. Also, there may be connecting pieces 129 locating at a middle of the drilling rod 120 for supporting and strengthening the drilling rod 120. The connecting pieces 129 such as steel plates may be attached to the said pipes by welding, for example. For sake of the clarity, even though the connecting pieces locate in the annular passage 120A, the connecting pieces 129 are arranged so that they do not prevent the medium to flow through the annular passage 120A. At top of the drilling rod 120 locating topmost relative to possible other drilling rods 120, there is a coupling for coupling the drilling rod 120 to the drilling rig such as to the rotating device of the drilling rig. The coupling herein may be a flange coupling, a thread joint, API joint, HEX joint or a bolt joint, for example. At bottom of the drilling rod 120 locating lowest relative to other possible drilling rods 120, there is the above-mentioned coupler 150 for coupling the drilling rod 120 to the down-the-hole hammer 116. If the DTH hammer 116 is not used, the drilling rod 120 may be coupled to the drill bit 110. Further, there may be a plurality of drilling rods 120 connected to each other for achieving a certain depth for the borehole, whereby the topmost drilling rod is connected to the drilling rig, following drilling rods 120 are coupled one after the other, and the lowest drilling rod 120 is attached to the down-the-hole hammer 116 or to the drill bit 110. For coupling the drilling rods 120 together, there is a flange coupling 140. According to an embodiment, instead of the flange coupling 140, there is an API joint being an internal threading at the end of the drilling rod and an external threading at the end of the following drilling rod, wherein said in- ternal and external threading correspond to each other. According to an embodi- ment, instead of the flange coupling 140, there is a coupling comprising a socket at the end of the drilling rod 120 and an extrusion portion at the end of the following drilling rod 120, wherein said socket and extrusion portion correspond to each other. Section of the socket and the extrusion portion may have a shape of square, hex, torx or such, for example. The coupling of this kind comprises a pin and a hole in radial direction of the coupling for removably locking the coupling. The blocking device 130, i.e., a guiding device, of the Figures comprises a housing 132 made of steel, for example. The blocking device 130, and in more detail, the housing 132 of the blocking device 130, splits the borehole to the bottom space 130B and to the upper space 130U, wherein the bottom space 130B is formed below the housing and between the housing 132 and the drill bit 110, and wherein the upper space 130U is formed / locates above the housing 132 and further is formed / locates between an inner wall of the borehole and the arrangement 100. A purpose of the blocking device 130 is to guide the medium and the cuttings in a controlled manner / way from the bottom space 130B to the annular passage 120A of the double-walled drilling rod 120. In other words, the purpose of the blocking device 130 is to keep the borehole and / or the pile casing clean of the cuttings, thus, the blocking device 130 prevents the cuttings being in contact to the inner wall of the borehole and / or the pile casing. Further, the housing 132 of the blocking device 130 of Figures 2–5 has a first open end 202, a second open end 204, an inner space 206 extending from the first open end 202 to the second open end 204, and a side 208 surrounding said inner space 206 and extending between the first open end 202 and the second open end 204. The blocking device 130 comprises a bearing 210 that is arranged to the inner space 206 for being coupled to the drilling rod 120, which bearing 210 is dis- closed in more detail below. The blocking device 130 comprises a gasket 160 that is arranged to said side 208 of the housing 132, which gasket 160 is disclosed in more detail below. The gasket 160 locates near said second open end 204. The drill- ing rod 120 extends through said first open end 202. The drill bit 110 extends through said second open end 206. The housing 132 of the blocking device 130 of Figures 1, 2, 4 and 5 en- closes partially the drill bit 110. The housing 132 is formed by parts having shape of a pipe and / or a cone, for example, which parts are being welded to each other, or which are removably coupled to each other by bolts, for example. In Figures 1, 2A, 2B, 4 and 5, the housing 132 of the blocking device 130 encloses substantially sides of the DTH hammer 116 and partially the drill bit 110. In Figures 1, 2A, 2B, 4 and 5, a bottom of the blocking device 130 locates near / above the drill head 114 in the direction of the middle axis MA’ of the blocking device 130. Illustrated in other words, the blocking device 130 extends between the down-the-hole hammer 116 in the direction of the middle axis MA’ of the down-the-hole hammer 116. A dis- tance between the bottom of the blocking device 130 and the drill bit 110 may be 0–200 mm, or 0–100 mm, or 50–100 mm, for example. Therefore, a maximum area of the inner wall of the borehole and / or the pile casing is not in connection to the cuttings and / or the loose soil during drilling, i.e., not in connection to the bottom space 130B during drilling. In Figures 3A and 3B, the housing 132 of the blocking device 130 encloses partially the coupler 150. The bottom of the housing 132 lo- cates on or above the DTH hammer 116. If the diameter of the borehole is near a diameter of the down-the-hole hammer 116, the blocking device 130 of Figures 3A and 3B may be used, because the housing 132 is not limiting a size of the DTH ham- mer 116 in radial direction of the borehole. The blocking device 130 of Figures 3A and 3B allows a maximum size for the DTH hammer 116 to be used. The housing 132 of the blocking device 130 of the Figures comprises a cone portion 134 at a bottom of the blocking device 130. The cone portion 134 is configured to be at an angle relative to a middle axis MA’ of the blocking device 130, or relative to the inner wall of the borehole, and thereby guiding the medium and the cuttings in a controlled way up. Said angle is between 0 degrees and 90, prefer- ably between 30 degrees and 60 degrees, relative to the middle axis MA’ of the blocking device 130. In Figures 1, 2, 4 and 5, the cone portion 134 locates near the drill head 114. In Figures 3A and 3B, the cone portion 134 locates near the top of the DTH hammer 116. Further, the blocking device 130 of the Figures comprises the above- mentioned gasket 160 at a side of the blocking device 130, wherein the gasket 160 has an annular shape. A material of the gasket may be rubber and / or plastic, for example. The gasket 160 fits against the inner wall of the borehole and / or the pile casing for sealing the borehole during the borehole being drilled, and in more de- tail, for sealing the bottom space 130B during drilling. The gasket 160 prevents the cuttings and the medium to flow from the bottom space 130B into a space between the blocking device 130 and the inner wall of the borehole / pile casing and further up to the upper space 130U of the borehole, wherein the inner wall of the bore- hole / pile casing mainly locates. The gasket 160 may be attached to the blocking device 130 by a screw connection, for example, which screw connection is not shown in the Figures. Further, the blocking device 130 has means for being arranged to the drill bit 110 or to the drilling rod 120. As illustrated in Figure 1, the blocking device 130 is integrated to the lowest drilling rod 120. In more detail, the blocking device 130 is welded to the second pipe 128 of the drilling rod 120. Further, as illustrated in Figures 2A, 2B, 3A, 3B, 4 and 5, the blocking device 130 comprises the above-mentioned bearing 210 via which the blocking de- vice 130 is coupled to the drilling rod 120 for preventing the drilling rod 120 to rotate the blocking device 130. In more detail, the blocking device 130 is coupled to the second pipe 128 of the drilling rod 120. Said bearing 210 prevents the drill- ing rod 120 to rotate the gasket 160 and reduces wearing of the gasket 160. Said bearing 210 may be any kind of suitable bearing, but preferably the bearing 210 is a sliding bearing, i.e., a plain bearing, providing durable and simple structure. The sliding bearing is made of babbitt, bi-material, bronze, jewels and / or plastic, for example. For reducing wearing of the sliding bearing of the blocking de- vice 130, the sliding bearing may comprise oil / lubricating particles that lubricates the sliding bearing and surfaces of the drilling rod and / or the blocking device against the sliding bearing. The lubricating particles of the sliding bearing are being released during wearing of the sliding bearing. For reducing wearing of the bearing 210 of the blocking device 130, a lubrication is supplied to the bearing 210. In Figures 4 and 5, the double-walled drilling rod 120 comprises a lubrication channel 420 being connected to the bear- ing 210. The lubrication channel 410 is arranged from the middle passage 120M of the drilling rod 120 to the bearing 210. In vicinity of the bearing, there may be gap(s) and / or groove(s) allowing the medium to pass the bearing, wherein said gap(s) and / or groove(s) are arranged to the drill bit 110, to the bearing 120 and / or to the blocking device 130. The medium, that is typically the pressurized air, passes the bearing and removes impurities attached to the bearing 210. Also, the medium herein typically comprises oil particles for lubricating the bearing 210, thus lower- ing friction between moving parts. For supplying the medium to the bearing 210, the lubrication channel 410 of the double-walled drilling 120 has a structure as follows. In Figures 4 and 5, the bearing 210 is against the double-walled drilling rod 120. As mentioned above, said double-walled drilling rod 120 has the first pipe 126 and the second pipe 128 and the connecting piece(s) 129 such as a steel plate(s) between said pipes. The lubrication channel 410 herein is a through-hole extending through said pipes 126,128 and the connecting piece(s) 129. A first end of the lubrication channel is in connection to the middle passage 120M of the drilling rod 120, and a second end of the lubrication channel is against the bearing 210. The through-hole may be ar- ranged in a lateral direction of the drilling rod 120, or at an angle relative to the lateral direction of the drilling rod 120, for example. The lubrication channel 410 is not in connection to the annular passage 120A of the drilling rod 120 for pre- venting the cuttings to flow to the bearing. The blocking device 130 of Figures 2A, 2B, 3A and 3B is thus coupled to the drilling rod 120, wherein the bearing 210 prevents the blocking device 130 to move in the direction of the middle axis MA’ of the drilling rod 120. In Figures 4 and 5, the drilling rod 120 comprises a flange 420 for preventing the blocking de- vice 130 to move in the direction of the middle axis MA’ of the drilling rod 120. The blocking device 130 is coupled against a lower surface of the flange 420, which cou- pling is locked by a holding block 430 being fastened against an upper surface of the flange 420. The holding block 430 is fastened to the blocking device 130 by screws, for example. Said screws are not shown in the Figures. There may be a bear- ing such as a sliding bearing arranged between a lower surface of the holding block 430 and an upper surface of the flange 420 (said bearing not shown in the Figures), and between the lower surface of the flange 420 and an upper surface of the block- ing device 130 (said bearing not shown in the Figures), for preventing wearing of the blocking device 130, the holding block 430 and / or the flange 420. The arrangement 100 may comprise a collector 40, i.e., a guider, ar- ranged on the top of the topmost drilling rod, thus between the topmost drilling rod and the rotating device 30 of the drilling rig. A purpose of the collector 40 is to guide the medium and the cuttings in a controlled way to further processing, such as to a container for storage of the cuttings, for example. The collector herein is a housing made of steel, for example. The collector has means, such as a flange cou- pling, for being fastened to the rotating device and to the drilling rod 120, for ex- ample. For sake of the clarity, the collector 40 disclosed herein is an example for guiding the medium and the cuttings in the controlled way to further processing, which guiding may be arranged in many various ways. Further, the collector 40 has a passage, such as a through-hole, that fits to the middle passage 120M of the drilling rod 120 and to the through-hole of the rotating device 30. Said passage is configured to receive the medium from the me- dium supply 20, and in more detail, from the conduit 22 of the medium supply 20. The collector 40 allows the medium to flow into the middle passage 120M of the drilling rod 120. The passage locates in a middle of the collector in an axial direc- tion of the collector. Further, the collector 40 comprises a flow-through channel 40F con- nected the annular passage 120A of the drilling rod 120. The flow-through channel 40F comprises a port at a side of the collector, via which the medium and the cut- tings are guided to further processing. The flow-through channel 40F is coupled to the collector 40 by a bearing, which allows the flow-through channel 40F and other structure of the collector 40 to rotate relative to each other. Specially, the bearing prevents the collector to rotate said port, which provides said port to be directed to a determined direction and stay in the determined direction. There may be a hose arranged to said port, which hose allows the medium and the cuttings to flow from said port to the container, for example. The flow-through channel 40F locates around the passage of the collector 40, and between said means such as between the flange couplings. Above-mentioned middle axis MA’ of the drilling rod 120, the drill bit 110 and / or the blocking device 130 are coincident relative to each other. Thus, the middle axis MA’ of the drilling rod, the drill bit and the blocking device are arranged to the same middle axis MA’. During drilling, said middle axis MA’ directions are coincident relative to a depth direction of the borehole. During drilling, longitudi- nal direction of the down-the-hole hammer 116 is collinear to the depth direction of the borehole. During drilling, the medium supply 20 supplies a medium through the rotating device 30, through the middle passage 120M of the double-walled drilling rod 120, through the down-the-hole hammer 116 and through the flow-through channel 110M of the drill bit 110 to the borehole, and the blocking device 130 and drilling rod(s) 120 guides the medium and cuttings, via the annular passage 120A around the middle passage 120M in the double-walled drilling rod 120, out from the borehole. It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The inven- tion and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

Claims 1. An arrangement (100) for drilling a borehole into a ground or rock, and for removal of cuttings out from the borehole by a medium, wherein the me- dium is a pressurized air, the arrangement (100) comprising a drill bit (110) for drilling boreholes, which drill bit (110) has a flow- through channel (110M) for guiding the medium to the borehole, a double-walled drilling rod (120) connected to the drill bit (110), the double-walled drilling rod (120) having a middle passage (120M) in connection to the flow-through channel (110M) of the drill bit (110), said middle passage (120M) allowing the medium to flow to the flow-through channel (110M), the double- walled drilling rod (120) further having, around the middle passage (120M), an annular passage (120A) allowing the medium and the cuttings to flow from the borehole to the annular passage (120A), a down-the-hole hammer (116) for producing a percussive movement during drilling the borehole, which down-the-hole hammer (116) is coupled be- tween the drill bit (110) and the double-walled drilling rod (120), and which down- the-hole hammer (116) is configured to supply the medium, received from the mid- dle passage (120M) of the double-walled drilling rod (120), to the flow-through channel (110M) of the drill bit (110), and a blocking device (130) for guiding the medium and the cuttings to the annular passage (120A) of the double-walled drilling rod (120).

2. The arrangement (100) as claimed in claim 1, c h a r a c t e r i z e d in that the arrangement (100) comprises a medium supply (20) for supplying the medium to the middle passage (120M) of the double-walled drilling rod (120), and a conduit (22) between the medium supply (20) and the middle passage (120M) of the double-walled drilling rod (120).

3. The arrangement (100) as claimed in claim 1 or 2, c h a r a c t e r - i z e d in that the arrangement (100) comprises a rotating device (30) for rotating the drill bit (110) and the double-walled drilling rod (120), the rotating device (30) being coupled to a top of the double-walled drilling rod (120).

4. The arrangement (100) as claimed in claim 3, c h a r a c t e r i z e d in that, the conduit (22) between the medium supply (20) and the middle passage (120M) of the double-walled drilling rod (120) is arranged via the rotating device (30).

5. The arrangement (100) as claimed in anyone of the preceding claims,c h a r a c t e r i z e d in that the blocking device (130) further comprises a gasket (160) fitted against the borehole for sealing the borehole.

6. The arrangement (100) as claimed in claim 5, c h a r a c t e r i z e d in that the blocking device (130) comprises a bearing (210) via which the blocking device (130) is coupled to the double-walled drilling rod (120) for preventing the double-walled drilling rod (120) to rotate the gasket (160) of the blocking device (130).

7. The arrangement (100) as claimed in anyone of the preceding claims, c h a r a c t e r i z e d in that the blocking device (130) comprises a bearing (210) via which the blocking device (130) is coupled to the double-walled drilling rod (120) for preventing the double-walled drilling rod (120) to rotate the blocking device (130).

8. The arrangement (100) as claimed in claim 6 or 7, c h a r a c t e r - i z e d in that the bearing (210) is a sliding bearing.

9. The arrangement (100) as claimed in anyone of the preceding claims, c h a r a c t e r i z e d in that the blocking device (130) substantially encloses sides of the down-the-hole hammer (116).

10. The arrangement (100) as claimed in anyone of the preceding claims, c h a r a c t e r i z e d in that a bottom of the blocking device (130) locates above the down-the-hole hammer (116) in a longitudinal direction of the down- the-hole hammer (116).

11. The arrangement (100) as claimed in any one of claims 6–10, c h a r a c t e r i z e d in that there is a lubrication channel (410) being connected to the bearing (210) of the blocking device (130).

12. The arrangement (100) as claimed in claim 11, c h a r a c t e r - i z e d in that the lubrication channel (410) is connected from the middle passage (120M) of the double-walled drilling rod (120) to the bearing (210).

13. The arrangement (100) as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the arrangement (100) is further used for pushing a pile casing in the borehole.

14. A method for drilling a borehole into a ground or rock by an arrange- ment as claimed in anyone of claims 1–13, the method comprising supplying a medium through the middle passage (120M) of the double- walled drilling rod (120), through the down-the-hole hammer (116) and through the flow-through channel (110M) of the drill bit (110) to the borehole, and guiding the medium and cuttings, via the annular passage (120A)around the middle passage (120M) in the double-walled drilling rod (120), out from the borehole.

15. The method as claimed in claim 14, the method further comprising pushing a pile casing in the borehole.

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