AN APPARATUS FOR DRILLING OPEN A TUNNEL AND DRILLING METHOD

Abstract: A drilling apparatus, especially apparatus redrilling an existing hole, in the drilling head of which there is, as the first advancing part, a cylindrical unit (4) with a diameter substantially smaller than that of the hole or the tunnel which is to be redrilled, and dimensioned to fit inside the original hole or pipeline (3) and by means of which unit steering forces from the walls of the original hole (3) steer the whole drilling apparatus.

Description: APPARATUS FOR DRILLING OPEN A TUNNEL AND DRILLING METHOD. The invention relates to a method according to patent claim 1 and a drilling apparatus according to patent claim 6 to re- drill an existing tunnel or hole. Previously known is as a replacement method of old sewer sys¬ tems by means of which a new pipeline is pulled into the old one. Also known is a drilling apparatus by means of which the old pipe is crushed and the waste forced to the surroundings in accordance with EP-publication 0 455 949, while pulling in a new pipe into the hole. A disadvantage on pulling in a new pipe is a substantial fall in the pipe diameter size and the fact that it is impossible to pull in a new pipe into a pipeline already collapsed. The disadvantage in crushing old pipelines and forcing produced waste to the tunnel walls is damage on the neighbor pipelines by sharp chips which can, due to tensions, fall back into the hole and even smoother running soil can cause friction which prevents the pulling-in of a new pipe into the hole. By means of a method and a drilling apparatus according to this invention these disadvantages are eliminated and the invention is characterized in what is presented in the enclosed patent claims. The advantage of this invention is that the pipeline can be either collapsed or not and replaced by a new pipeline with the same or a greater outer diameter. The old pipeline and possible soil are removed from the hole and so they do not have any impacts on the surroundings. The drilling apparatus moves forward following the old pipeline and can curve, upon need. In the following the invention is disclosed with reference to the enclosed drawing, where Fig. 1 is a side section of the drilling apparatus. Fig. 2 is the steering pilot unit. Fig. 3 is the packing of the pilot unit Fig. 4 is the cross-section of an optional drilling apparatus. Fig. 5a is the cross-section of portion A-A. Fig. 6a is the cross-section of portion B-B. Figure 1 shows a drilling apparatus furnished with a penumatic percussion hammer. Compressed air flows along pipe 2 transmit¬ ting also rotational motion to the drilling apparatus. In the front end of the pilot unit there is a percussion bit holder 8 producing both hammering and also rotational motions. To break down the pipeline 3, a ring bit 6 with crushing bits 5 is fix¬ ed by a thread to the rear end of the percussion bit holder. Compressed air, operating the percussion hammer 1, is already by now under much lower pressure and running along channel 9 to the front side of the ring bit 6, from where it conveyes the crushed waste from pipe 3 to the back over pipe 7. If pipe 3 is blocked, compressed air does not escape forward. A pilot unit 4 fixed with a thread to pit holder 8 to steer, upon need, the forward travel of the drilling apparatus. For pilot unit 4 a diameter size is chosen that it will fit into pipeline 3 with sufficient clearance. If the drilling appar¬ atus tends to drift 3 towards a wall inside pipeline 3, the pilot unit 4 grasps the pipeline wall and the force, energated thereby, starts to affect the whole drilling apparatus turnig it little by little closer to the center inside the pipeline. The pilot unit can be freely spinning in the bit holder 8 top end and its fixation to the bit holder can allow also a slight swinging in relation to the bit holder centre line. Figure 2 shows a pilot unit 11 with crushing bit 5. Scavenging air or water shall, at least in this case, also be conveyed to the front side of this blade during crushing. For this purpose a hole has been made in the component 12. A special valve must be fitted in bit holder 8, by means of which the travel of scavenging air or water can be steered either to ring bit 6 or also to the bit in the pilot unit which is also used for crushing. Then the valve is controlled either by means of the pressure line or the electric line from the mouth of hole or there is in bit holder 8 or in component 11 a sensor detecting whether component 11 is in crushing state or not. Figure 3 shows a pilot unit most advantageously fitted with a packing part 13 made of rubber taking support from the re¬ placeable pipe or a corresponding wall in the former tunnel, and thereby preventing compressed air or water, conveyed to ring bit 6, from escaping forward past the pilot unit. In the first place, packing 13 is needed when the pilot unit 11 is not crushing, i.e. the old pipeline has not collapsed and is free from blockages. The steering pilot unit 4 can also be a bushing, whereby the bit holder is the foremost part to enter out off it and, in addition, there is a thread in the top of the bit holder for applying a separate tip bit. Most advantageously, the diameter of the tip bit is thereby very close to the outer diameter of the bushing. Naturally, the ring bit 6 can be replaced by a bit holder ex¬ tension of corresponding size, whereby they both are made of the same billet and the bit holder can be used to drill an one-size hole only. The new pipe is pulled into the hole and the joint between ring bit 6 and the new pipe 10 is a lap joint 39 with collar, whereby the pipe is secured axially by the ring in pipe 10 end to the ring bit 6. The pipe is not rotating though the ring bit is spinning. Instead of being crushing button bits, the bits can also be chisel bits. Anyhow, the bit and the bit holder as well as the pilot unit can be joined together by means of different com¬ binations in order to enable great convertability and a great number of diameters, to facilitate manufacturing and decrease the mass of waste being produced. Figure 4 shows an example of how pressure medium is conveyed to the pilot unit, the outer shell 29 of which is a cylinder, in the front end of which there are crushing buttons 5 and how it is also possible to convey medium to the buttons 5. The bit holder 14 has a center hole 15 for transmission of medium to a valve assembly formed in the pilot unit. On bit holder 14 there is a pilot bit 17 and a ring bit 18 about it. The ring bit is supported by protecting pipe 16 and can move slightly lengthwise and spin in the supportive protecting pipe 16. Between pilot blade 17 and the ring bit there is a push-pull joint allowing removal of bit holder 14, pilot blade 17 and the whole pilot unit from the drilling top end by pulling the bit holder while the protecting pipe 16 and the ring bit remain in place. In a state according to the figure the pilot unit is not crushing. Access of compressed air to hole 15 and to the front end of the pilot unit over channel 34 is blocked. Instead, air has access over channel 24 to the packing 22 bending it to become packed against the pipe which is being crushed. Like¬ wise, air has access over channel 20 to the front side of the pilot bit and the ring bit that are crushing the pipe, whereat drill waste is conveyed by the air backward over channel 19. In this state, due to clearances, the outer shell of the pilot unit can swing slightly on a supporting ring 23, which in its turn is fixed to a cylindrical part 38 that has two channels 25 and 24 and can gliding on bit holder 14. The outer shell 29 is forced forward by spring 27 arranged between flanges 32 and 26. Flange 26 is connected by a bolt to the tip of bit holder 14. A thick rubber ring 21 functions as axially elastic means. The outer shell 29 steers the travel of the drilling apparatus in the pipeline which is being chrushed and is able to yield a little and turn the drilling apparatus slowly step by step in the pipeline direction. When the bit holder is hammering, the pilot unit does not, however, hammer hardly at all, because the shell 29 of the pilot unit can move back against spring 27 as much as the length of a stroke and even more. So the pilot unit does not tend to break the pipeline which is being crush¬ ed and drill itself through it in a low-gradient pipeline curve, for instance. The pilot unit shiftes over to drilling when the front buttons 5 hit an obstacle. The outer shell with parts 32 and 35 fixed on it moves back and keeps also pushing backward the two- channel 24, 25 part 38 and rubber ring 21 till bushing 36 in¬ side spring 27 strikes against flange 26. The stroke of bit holder 14 starts to get transmitted also to buttons 5 and the outer shell 29 starts to work, too. In this state compressed air is also directed over the centre hole 15 of bit holder 14 to channel 25 and through the same over holes 28 of the outer shell 20 to crushing buttons 5. Drill waste can be conveyed from the shell outside by compressed air to channel 19 or in¬ side shell 29 over valves 31 and the holes in flange 32 to channel 37, to which a hole opens from between flange 26 and part 38. Due to clearance, channel 24 is not fully closed, neather is channel 20. Accordingly, packing 22 can function upon need. In that case the drill waste is conveyed completely through the inside of shell 29 to channel 19. The cross-section illustrated in figure 5a shows how the spinning motion of bit holder 14 is transmitted from flange 26, fixed to the front of the bit holder, to put also the outer shell 29 into spinning motion. In the outer shell there is a flange 35 which has three wide grooves, in which flange 26 the buttons can glide lengthwise while transmitting spinn¬ ing motion. Figure 5b shows how bit holder 14 and pilot blade 17 can be pulled out while ring bit 18 stays in place. In the pilot bit there are big grooves in three directions, whereat the bit can be pulled out even though previous known turning cylinders, which steer the drill bit, would have been placed, similarly, in three peripheral positions in the protection pipe 16, when the grooves are fitted at the cylinders. By means of the drilling apparatus it is also possible to pull into the formed tunnel a new pipeline fixed to the the ring bit while pushing it from the tunnel mouth. It is also possib¬ le to assemble a new pipeline only by pushing it from the tun¬ nel mouth with a power unit, if it is unsuitable for pulling. By means of this method a renewable able pipe can be replaced even by a plastic pipe, because the surface of the new hole remains smooth and does not have any sharp edges to damage the plastic surface. Steering can be taken from the replaceable pipe in utilizing, for instance, rolls fixed to the pilot unit and travelling along the inner surface of the replaceable pipe. Teh drilled waste can be removed by means of a scaveng¬ er, a screw conveyor or by pumping either in the drilling direction or backward. Possible damage of the surface of the replacement pipe can be avoided using a separate pipeline, which can be placed in the hole and inside of which the drill waste moves. By means of this pipeline drill waste can also be conveyed forward.

Claims: PATENT CLAIMS 1. A method to renew an underground, especially a sewer system pipeline (3), by which method replacement of the pipeline is carried out by a drilling apparatus travelling forward in the pipeline (3) and fitting a replacement pipe (10,16) into the hole characterized in that the drilling apparatus gets its steering quality from the inner surface of the replaceable pipe and that a corresponding hole is drilled for the new pipeline (10,16), the replaceable pipeline (3) is crushed and the produced drill waste conveyed out from the pipeline with the drilling apparatus . 2. A method according to patent claim 1 characterized in that ring bit (6) in the drilling apparatus is spinning and pulls the not-spinninig replacement pipeline (10,16) by means of a collared lap joint (39). 3. A method according to patent claims 1 and 2 characterized in that the drill waste is conveyed over a separate pipe either in the drilling direction or backward. 4. A method according to any of patent claims 1-3 characteriz¬ ed in that the materials inside the replaceable pipe (3) are drilled with bit 5 fixed to part (11), (29) that steers the drilling apparatus. 5. A method according to any of patent claims 1-4 characteriz¬ ed in that the reversing of bit 5 into rear position in relation to the bit holder (14) due to an obstacle inside the replaceable pipe (3) starts the drilling of said obstacle with the bit (5) . 6. A method according to any of patent claims 1-5 characteriz¬ ed in that the reversing of bit 5 into rear position opens access of scavenging water to the bit (5) . 7. A drilling apparatus to realize the method according to patent claim 1 characterized in that in its front it has a pilot unit (4), (29) and behind this unit a ring bit (6), (8), with a greater diameter than the pilot unit, by means of which the replaceable pipe is removed by drilling, and which ring bit has channels (7), (19) for conveying drill waste backward through the bit. 8. A drilling apparatus according to patent claim 7 charac¬ terized in that in the front of the drilling apparatus pilot units (4), (11), (29) with different diameter sizes can be exchanged and the pilot unit and bit holder (14) can be pulled off the drilling head through the ring bit (18) and protection pipe (16). 9. A drilling apparatus according to patent claim 7 or 8 characterized in that the front surfac of the pilot unit (11), (29) is furnised with crushing bits (5). 10. A drilling apparatus according to any of the patent claims 7 - 9 characterized in that pressure medium conveying out the drill waste can be conducted to the front side of the pilot unit (11), (29). 11. A drilling apparatus according to any of the patent claims 7 - 10 characterized in that to the front of pilot unit (11), (29) a packing (13, (22) is fixed preventing scavenging air from escaping to the pipeline which is being redrilled. 12. A drilling apparatus according to any of the patent claims 7 - 11 characterized in that it is fitted with a valve through which scavenging air can be conducted to the front side of the drilling pilot unit (11), (29).

Inventors: ILOMAEKI VALTO, ILOMAEKI, VALTO
Applicants: ILOMAEKI VALTO, ILOMAEKI, VALTO
Application year: 1995
Main classification: E21B10
IPC codes: E21B7, E21B10, F16L1, F16L55