WO1996020330A1

WO1996020330A1 - Drilling apparatus

Info

Publication number: WO1996020330A1
Application number: PCT/FI1994/000579
Authority: WO
Inventors: Risto Wisakanto
Original assignee: Oy Winrock Technology Ltd
Priority date: 1994-12-23
Filing date: 1994-12-23
Publication date: 1996-07-04
Also published as: AU685570B2; AU1371395A

Abstract

A drilling device (1) operates as a down-the-hole drill by a feeding motion along its longitudinal direction (s), a to-and-from hammering motion (t) and a rotational motion (w) around its longitudinal axis (s). The drilling apparatus includes hammering means (8), arranged functional by pressure medium in liquid form led by a second flow arrangement (9) from the pressure medium system of the drilling apparatus. The hammering means (8) include a hollow frame part (7), a valve and flow directing arrangement (o) controlling the flow of pressure medium taking place at the same, a piston arrangement (10) carrying out the said hammering motion by influence of the above and an accumulator arrangement (11) for storing pressure medium. To minimize the cross section of the hammering means (8), a flow way of the second flow arrangement (9) in connection with the piston arrangement (10), such as an input flow way (9a) and/or an output flow way (9b), is divided in two or more flow parts.

Description

Drilling apparatus

The invention relates to a drilling apparatus to drill a hole into the ground, whereby the drilling apparatus has at least:

- a drilling device, the drilling end of which inclu¬ des at least drilling means for drilling a hole and the other end of which includes jointing means for fastening of a drill rod to increase the drilling depth of the drilling apparatus, whereby the drilling device is arranged to operate as a down-the-hole drill by a feeding motion along its longitudinal direction and by a to-and-from or a like hammering motion as well as by a rotational motion around its longitudinal axis, and in connection of which there exists prefe¬ rably flushing means to remove drilling waste genera¬ ted by the drilling means, that are arranged func¬ tional by flushing medium led by a first flow arrange- ment, and

- hammering means, placed in connection with the drilling means in the drilling device, that are arranged functional by pressure medium in liquid form led by a second flow arrangement from the pressure medium system of the drilling apparatus, whereby the hammering means include a hollow frame part, which has, at least to achieve a hammering motion, a valve and flow directing arrangement or a like controlling the flow of pressure medium taking place at the hammering means and a piston arrangement or a like carrying out the said hammering motion by influence of the above, wherein particularly at least to minimize the cross section of the hammering means, at least one flow way of the second flow arrangement, essentially in connection with the same, such as an input flow way and/or an output flow way, is divided in two or more flow parts. Arrangements such as described above, in which the hammering means operated by compressed air, are placed advantageously at the drilling head of a down-the-hole drill, have already been known for a long time and they have also been widely used in mineral industry. In this case an advantage of the hammering means placed in the hole is, that the strokes of the same are aimed directly to the drill bit, whereby it is possible to decrease energy loss and unnecessary wearing of components belonging to the arrangement to lower level than in solutions, in which the hammering means are placed in the rear end of the drill rods. In connection with pneumatic drilling machines compressed air is usually used to flush drilling waste, also. However, it is not beneficial to use the drilling machine with compressed air, because a very high power of the compressor unit is thus needed. In addition to that, the efficiency of a pneumatic system is clearly lower than the same of a hydraulic system.

The use of a hydraulic drilling machine is known for example from Patent Publication PCT/EP89/00256. The drilling device according to the above publication is moved by an oscillating motion as distinct from the usual rotational motion, that takes place continuously to the same direction. The reason for this is, that for feeding of pressure medium into the hammering unit placed in the drilling head, separate feeding hoses are being used, whereby, when adding or removing drill rods to/from the drilling device, the feeding hoses are being fed into the hole or wound up from the hole. To achieve an optimum drilling effect and to save the feeding hoses, the twisting angle is preferably limited between 180° - 360°. To minimize wearing of the feeding hoses, an application has been presented in the publication, in which each drill rod has two longitudinal ducts that are open outwards, in which the feeding hoses are placed for feeding and leading off of the pressure oil for the hammering unit of the the drilling device placed in the hole. The hydraulic hoses are thus advantageously inside the circle of the drill rod. Feeding of the compressed air is carried out advantageously by applying conventional technics and leading it through the hollow drill rod.

The solution according to the publication above is not very good in practice, because the handling of feeding hoses requires massive equipment. It is necessary to arrange winding drums and driving mechanisms for both feeding hoses, the space utilization of which is determined by the depth of the hole to be drilled. The handling of the feeding hoses during a drilling situation is naturally difficult, wherein careless installation and use may cause environmental damages when the feeding hoses are injured. Naturally, when drilling holes of different depths, correspondingly hoses of different lengths must be used or they must be lengthened with joints, which again causes environ¬ mental risks. The hydraulic hammer placed in the front end of the drill rods has not been presented in greater detail in the publication.

Thus it is known from both pneumatic and hydraulic drilling apparatuses to place the hammering unit inside the protecting tube at the drilling head. In this case there has been placed inside the frame of the hammering unit a valve and flow directing arrange- ment controlling the flow of pressure medium and a piston arrangement carrying out the said hammering motion by influence of the above. In conventional constructions the flow ways of the second flow arran¬ gement, that are in connection with the hammering unit, are formed of one input flow way and of one output flow way. In addition to that, when placing the hammering unit at the drilling head of the drilling device, there must be placed a flushing duct, acting as the first flow arrangement, in the hammering unit, also. This is why, when applying traditional solu¬ tions, the cross-section of the hammering unit always gets relatively big, which fact naturally has a remarkable influence on the overall construction and the manufacturing costs of the drilling device. On the other hand solutions are known from certain types of drilling devices, also, in which particularly for minimizing the cross section of the hammering means, a flow way of the second flow arrangement, essentially in connection with the same, such as an input flow way and/or an output flow way, is divided in two or more flow parts.

One practical problem concerning present down-the-hole drills is particularly the controlling of the pressure medium of the hammering means, whereby it is known for example from EP-application 22865 to apply an accumu¬ lator arrangement, placed essentially apart from the hammering means, to stabilize pressure levels. In this case it is necessary to use a separate compensation device, which has dividing places for the flow ways, between the drilling device and the drill rod being attached to the same. The solution in question is inconvenient particularly in the sense of manufactu¬ ring and maintenance because of its complicated construction.

It is an aim of the drilling apparatus according to this invention to achieve a decisive improvement in the problems presented above and thus to raise subs¬ tantially the level of knowledge in the field. To achieve this aim, the drilling apparatus according to the invention is primarily characterized in that the drilling device includes as well an accumulator arrangement or a like, for storing pressure medium, in connection with the second flow arrangement , that is arranged in the longitudinal direction immediately after the hammering means and which is placed prefera¬ bly centrically on the same longitudinal axis between the piston arrangement of the hammering means and the dividing arrangement of the flow ways.

The most important advantages of the drilling appara¬ tus according to the invention are the simplicity of its construction and profitableness particularly in the sense of manufacturing costs. It is possible to optimize the cross-section of the hammering means according to the invention in a way, that placing of the hammering means immediately after the drill bit at the drilling head does not make any extra demands for example on the dimensioning of the protecting tube covering the hammering means and the drill rods. In addition to that, the hammering means and the accumu¬ lator arrangement, when being arranged as an integra¬ ted entirety and placed directly after one another, may be changed by cartridge principle as a whole, when required. This makes the maintenance particularly of the components in question much easier, because in this case either one of them may be taken in for service as a whole, when required, whereby a new corresponding component may be installed in the drilling device immediately in the place of the same. In addition to that, when placing the accumulator arrangement as near as possible to the hammering means, problems concerning loss of pressure or the like may be avoided.

Advantageous embodiments of the drilling apparatus according to the invention are presented in the other, dependent claims.

In the following description, the invention is illu¬ strated in detail with reference to the appended drawings. In the drawings, Fig. 1 shows a view, that is half-cut longitudinally from separate places, of a drilling apparatus according to the invention, wherein the hammering means are placed in connection with the drill bit.

Figs. 2a and 2b show cross-sectional views along lines Y-Y and X-X in fig. 3,

Fig. 3 shows a partial longitudinal section of a dividing arrangement placed in connection with the hammering means,

Fig. 4 shows a longitudinal section of the hammering means, that are arranged, as an advantageous embodiment of the invention, as an integrated entirety, and

Fig. 5 shows an advantageous piston arrangement of the drilling apparatus according to the invention.

Drilling apparatus to drill a hole into the ground, whereby the drilling apparatus has at least:

- a drilling device 1, the drilling end I of which includes at least drilling means 2 for drilling a hole and the other end II of which includes jointing means 3 for fastening of a drill rod 4 to increase the drilling depth of the drilling apparatus. The drilling device 1 is arranged to operate as a down-the-hole drill by a feeding motion along its longitudinal direction s and by a to-and-from or a like hammering motion t as well as by a rotational motion w around its longitudinal axis 8. In connection of the drilling device 1 there exists preferably flushing means 5 to remove drilling waste generated by the drilling means 2, that are arranged functional by flushing medium led by a first flow arrangement 6, and

- hammering means 8, placed in connection with the drilling means 2 in the drilling device 1, to achieve a hammering motion, that are arranged functional by pressure medium in liquid form led by a second flow arrangement 9 from the pressure medium system of the drilling apparatus. The hammering means 8 include a hollow frame part 7, which has, at least to achieve a hammering motion, a valve and flow directing arrange¬ ment o controlling the flow of pressure medium taking place at the hammering means 8 and a piston arrange¬ ment 10 carrying out the said hammering motion by influence of the above, wherein particularly at least to minimize the cross section of the hammering means 8, at least one flow way of the second flow arrange¬ ment 9, essentially in connection with the same, such as an input flow way 9a and/or an output flow way 9b, is divided in two or more flow parts.

The drilling device 1 includes as well an accumulator arrangement 11 or a like, for storing pressure medium, in connection with the second flow arrangement 9, that is arranged in the longitudinal direction s immediate¬ ly after the hammering means 8 and which is placed preferably centrically on the same longitudinal axis s between the piston arrangement 10 of the hammering means 8 and the dividing arrangement 13 of the flow ways.

In the embodiment presented in fig. 1 the hammering means 8 are arranged inside a protective tube SP, shown by a line of dots and dashes, in connection with the drill bit 2, shown correspondingly by a line of dots and dashes. In this case for leading of flushing medium, the first flow arrangement 6 is arranged to be led centrically through the piston arrangement 10, in which case in the other end II of the drilling device 1 there exists coupling means 12 in addition to the jointing means 3, to couple the first flow arrangement 6 and the second flow arrangement 9 with an input flow duct 9a', an output flow duct 9b' and a flushing medium duct 6' , that exist in a drill rod 4 being connected to the drilling device 1. In this case, the first flow arrangement 6 for leading of flushing medium is arranged, as an advantageous embodiment of the invention, to be directed centrically through the accumulator arrangement 11 placed after the piston arrangement 10, that is situated at the drilling end I of the drilling device 1. In this case further, as an advantageous embodiment, the accumulator arrange- ment 11 is connected to the flow parts 9al, 9a2, 9a3, 9a4 and 9bl, 9b2, 9b3, 9b4 of the input flow way 9a and the output flow way 9b of the second flow arrange¬ ment 9.

With reference to figs. 1, 4 and 5 the piston arrange¬ ment 10 of the hammering means 8 includes at least one slide piston 10a moving in the longitudinal direction s of the frame part 7, the first end I' of which acts as a hammering head, whereby the hammering means 8 include as well coupling means 12 to couple the flow ways 9a, 9b of the second flow arrangement 9, that are in connection with the hammering means 8, with the pressure medium system of the drilling apparatus. In this case in connection with the hammering means 8 there has been arranged a dividing arrangement 13, as shown in figs. 1 and 3, to divide the input flow way 9a and the output flow way 9b of the second flow arrangement 9, that are connected to the piston arrangement 10 belonging to the the hammering means 8, into several flow parts by dividing points Jl, J2 placed advantageously at a distance e from each other in the longitudinal direction s. The flow ways 9a, 9b of the second flow arrangement 9 in connection with the hammering means 8, are advanta¬ geously each formed of a recess, such as a groove or a like, placed on the outer surface of piston arrange- ment 10 essentially in the longitudinal direction s, whereby flow of the pressure medium in connection with the hammering means 8 at least partly takes place between the piston arrangement 10 and the frame part 7. In this case as an advantageous embodiment, the flow parts of the flow ways 9a, 9b of the second flow arrangement 9 in at least part of the piston arrange¬ ment 10 are arranged, when viewed cross-sectionally, symmetrically, preferably as recesses placed on the outer surface of the piston arrangement 10 in the longitudinal direction s. Further, as an advantageous embodiment, the input flow way 9a and the output flow way 9b of the second flow arrangement 9, that are in the piston arrangement 10, are divided into four parts 9al, 9a2, 9a3, 9a4, 9bl, 9b2, 9b3, 9b4, each, whereby they are arranged, when viewing also the piston arrangement 10 cross-sectionally, preferably in turn at an angle of 45° in relation to each other, as in figs. 2a and 2b, and on the outer surface of the piston arrangement 10, as shown in fig. 5. The refe- rence letter o in fig. 5 represents a control flow duct of the valve arrangement and the reference code tv represents a leak flow duct of the gaskets.

As a particularly advantageous embodiment with refe- rence to fig. 4, the hammering means 8 are arranged as an integrated entirety, such as a cartridge or a like, that may be installed/removed essentially as a whole from the drilling apparatus. This matter has a very remarkable meaning concerning maintenace carried out at the working site, because when applying traditional solutions, the operations concerning particularly the hammering means must be carried out by removing the 10 parts belonging to the hammering means nearly one at a time from the drilling apparatus.

Further, with reference to fig. 4, to form an integra- ted entirety, the first end I' of the frame part 7 is closed by means of a closing part 15, that is connec¬ ted to the frame part 7 by fixing organs 14, such as by welding, screw coupling or correspondingly, whereby at the other end II' of the frame part 7 there is a shoulder 16, that restricts the movement of the piston arrangement 10 in the longitudinal direction s. Further, as an advantageous embodiment, the frame part 7 surrounding the hammering means 8 includes at the other end II' of the same an extension part 7' , that starts from the bottom part 16 and is directed in the longitudinal direction s away from the piston arrange¬ ment 10, for the installing of the accumulator arran¬ gement 11 and the dividing arrangement 13 inside the extension part 7' .

It is obvious, that the invention is not limited to the embodiments presented or described above instead it can be modified to a great extent within the basic idea. For one thing the hydraulic fluid of the hamme¬ ring means may be transmitted in connection with the drill rods by feeding hoses or correspondingly. Correspondingly the first flow arrangement of the flushing means may be formed of two ducts, whereby feeding of the flushing medium takes place through the first duct and suction of the flushing medium takes place through the second duct through interiors of the drilling device and the drill rods. Correspondingly, the turning motion of the drilling apparatus may be arranged reciprocating, whereby, however, a more complicated and uncertain controlling and regulating technics is required than that for the above described application.

Claims

Claims :

1. Drilling apparatus to drill a hole into the ground, whereby the drilling apparatus has at least:

- a drilling device (1), the drilling end (I) of which includes at least drilling means (2) for drilling a hole and the other end (II) of which includes jointing means (3) for fastening of a drill rod (4) to increase the drilling depth of the drilling apparatus, whereby the drilling device (1) is arranged to operate as a down-the-hole drill by a feeding motion along its longitudinal direction (s) and by a to-and-from or a like hammering motion (t) as well as by a rotational motion (w) around its longitudinal axis (s), and in connection of which there exists preferably flushing means (5) to remove drilling waste generated by the drilling means (2), that are arranged functional by flushing medium led by a first flow arrangement (6), and

- hammering means (8) , placed in connection with the drilling means (2) in the drilling device (1), to achieve a hammering motion, that are arranged func¬ tional by pressure medium in liquid form led by a second flow arrangement (9) from the pressure medium system of the drilling apparatus, whereby the hamme¬ ring means (8) include a hollow frame part (7), which has, at least to achieve a hammering motion, a valve and flow directing arrangement (o) or a like control¬ ling the flow of pressure medium taking place at the hammering means (8) and a piston arrangement (10) or a like carrying out the said hammering motion by influence of the above, wherein particularly at least to minimize the cross section of the hammering means (8), at least one flow way of the second flow arrange¬ ment (9), essentially in connection with the same. such as an input flow way (9a) and/or an output flow way (9b), is divided in two or more flow parts, characterized in that the drilling device (1) includes as well an accumulator arrangement (11) or a like, for storing pressure medium, in connection with the second flow arrangement (9), that is arranged in the longitu¬ dinal direction (s) immediately after the hammering means (8) and which is placed preferably centrically on the same longitudinal axis (s) between the piston arrangement (10) of the hammering means (8) and the dividing arrangement (13) of the flow ways.

2. Drilling apparatus according to claim 1, the drilling device (1) of which is at least partly arranged inside a protective tube (SP) or a like, whereby the hammering means (8) are arranged at the drilling end (I) of the drilling device (1) in connec¬ tion with the drilling means (2), such as with one or more bits or the like, whereupon to lead flushing medium, the first flow arrangement (6) is arranged to be led, preferably centrically through the piston arrangement (10), in which case in the other end (II) of the drilling device (1) there exists coupling means (12) in addition to the jointing means (3), to couple the first flow arrangement (6) and the second flow arrangement (9) with an input flow duct (9a' ) , an output flow duct (9b*) and a flushing medium duct (6'J, that exist preferably in a drill rod (4) being connected to the drilling device (1), characterized in that the first flow arrangement (6) for leading of flushing medium is arranged to be directed, preferably centrically through the accumulator arrangement (11) placed after the piston arrangement (10), that is situated at the drilling end (I) of the drilling device (1) .

3. Drilling apparatus according to claim 1 or 2, characterized in that the accumulator arrangement (11) is connected to two or more flow parts (9al,9a2,9a3,- 9a4 and/or 9bl,9b2,9b3,9b4) of the flow ways, such as the input flow way (9a) and/or the output flow way (9b), of the second flow arrangement (9).

4. Drilling apparatus according to any of claims 1 to 3 above, wherein the piston arrangement (10) or the like of the hammering means (8) includes at least one slide piston (10a) moving in the longitudinal direction (s) of the frame part (7), the first end (I') of which acts as a hammering head, whereby the hammering means (8) include as well coupling means (12) to couple at least the flow ways (9a, 9b) of the second flow arrangement (9) , that are in connection with the hammering means (8), with the pressure medium system of the drilling apparatus, characterized in that in connection with the hammering means (8) there has been arranged a dividing arrangement (13) for the pressure medium flow, to divide at least the flow ways, such as the input flow way (9a) and the output flow way (9b) of the second flow arrangement (9), that are in connection with the hammering means (8) , such as with the piston arrangement (10), into several flow parts by dividing points (Jl, J2) placed preferably at a distance (e) from each other in the longitudinal direction (s) .

5. Drilling apparatus according to any of claims 1 to 4 above, wherein at least one flow way of the second flow arrangement (9), that is in connection with the hammering means (8), is formed of a recess, such as a groove or a like, placed on the outer surface of piston arrangement (10) essentially in the longitudinal direction (s), whereby a flow of the pressure medium in connection with the hammering means (8) at least partly takes place between the piston arrangement (10) and the frame part (7), characterized in that in at least part of the piston arrangement (10), the flow parts of the flow ways (9a, 9b) of the second flow arrangement (9) are arranged, when viewed cross-sectionally, symmetrically, preferably as recesses placed on the outer surface of the piston arrangement (10) in the longitudinal direction (s).

6. Drilling apparatus according to any of claims 1 to 5 above, characterized in that at least the flow ways, such as the input flow way (9a) and the output flow way (9b) of the second flow arrangement (9), that are in the piston arrangement (10), are divided into preferably four parts (9al,9a2,9a3,9a4,9bl,9b2,9b3, 9b4) , each, whereby they are arranged, when viewing the piston arrangement (10) cross-sectionally, prefer- ably in turn at an angle of 45° in relation to each other.

7. Drilling apparatus according to any of claims 1 to 6 above, characterized in that at least the hammering means (8) are arranged as an integrated entirety, such as a cartridge or a like, that may be installed/removed essentially as a whole from the drilling apparatus.

8. Drilling apparatus according to claims 7, characterized in that to form an integrated entirety, the first end (I¹) of the frame part (7) is closed by means of a closing part (15) , that is connected to the frame part (7) by fixing organs (14), such as by welding, screw coupling or correspondingly, whereby at the other end (II') of the frame part (7) there is a bottom part (16), such as a shoulder or a like, that restricts at least the movement of the piston arrange¬ ment (10) in the longitudinal direction (s).

9. Drilling apparatus according to claim 8, characterized in that the frame part (7) surrounding the hammering means (8) includes at the other end (II') of the same an extension part (7'), that starts essentially from the bottom part (16) and is directed in the longitudinal direction (s) away from the piston arrangement (10), for at least the installing of the accumulator arrangement (11) and the dividing arrange¬ ment (13) inside the extension part (7').