Drilling robot with an extrusion unit
Patent Information
- Application Number
- EP2023715466
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-03-24
- Publication Date
- 2026-01-21
AI Technical Summary
Traditional borehole drilling for geothermal probes is inefficient, space-intensive, energy-consuming, noisy, and causes landscape damage due to the need for large compressors and drill pipes, limiting access to geothermal heat for many buildings.
A drilling robot with a movement unit, drilling unit, and extrusion unit that produces a pipe within the borehole using a melting unit for solid-state filament, which is cooled and then melted to form a stable pipe for support and as a heat exchanger, along with a water-based flushing system to manage cuttings, allowing for precise and efficient borehole creation without external drill pipes.
Enables safe and efficient drilling in loose underground conditions, reducing energy consumption and environmental impact while providing a stable borehole structure for geothermal applications, allowing for deeper and more precise borehole creation.
Smart Images
Figure EP2023057632_03102024_PF_FP_ABST
Abstract
Description
[0001] Drilling robot with an extrusion unit
[0002] Technical Field
[0003] The invention relates to a drilling robot for drilling a borehole . The drilling robot comprises a movement unit for moving and stabili zing the drilling robot inside the borehole , a drilling unit for drilling the borehole and an extrusion unit for producing a pipe within the borehole supporting the borehole . A material feed unit feeds extrusion material into the extrusion unit .
[0004] Background Art
[0005] Heat generation through geothermal energy plays a crucial role in the worldwide success ful heat transition . Boreholes for geothermal probes are traditionally drilled with a pneumatic hammer drill , wherein a compressor and a drill rig are arranged outside the borehole and the drill energy is trans ferred to the drill head inside the borehole via a drill pipe . Cuttings are flushed out of the borehole . With increasing depth of the borehole , the pressure drop of the compressed air immensely increases along the drill pipe . A very large compressor is needed to generate the necessary pressure and flow volume .
[0006] Such a drill system requires a lot of space . The process is energy-intensive , expensive , imprecise , causes noise and massive damage to the landscape . As a result , many buildings cannot benefit from geothermal heat or are equipped with other heating systems .
[0007] Disclosure of the Invention
[0008] The problem to be solved by the present invention is therefore to provide a drilling robot for drilling a borehole which can safely operate in a loose underground .
[0009] This problem is solved by the drilling robot according to the independent claim . According to this , the drilling robot for drilling a borehole comprises
[0010] - a movement unit for moving and stabili zing the drilling robot inside the borehole ,
[0011] - a drilling unit for drilling the borehole , in particular comprising a rotary hammer unit with a drill head, a rotating system and a hammering system,
[0012] - an extrusion unit for producing a pipe within the borehole to support the borehole . The pipe prevents the borehole from collapsing, especially in the loose sediment layers found close to the surface within the first fi fty meters . The pipe can not only support the walls of the borehole but also act as the outer pipe of the coaxial heat exchanger to be installed in the borehole .
[0013] - a material feed unit feeding extrusion material into the extrusion unit .
[0014] The extrusion unit comprises a melting unit for melting the extrusion material . A melting unit has the advantage that material in a solid state can be fed into the extrusion unit . Solid-state material is easy to handle , easy to transport and allows a simpli fied storage . The melting unit melts the solid-state material into a liquid state such that the pipe can easily be formed .
[0015] In particular, the extrusion material fed into the extrusion unit is a filament . In particular, a filament is a raw material in a wire-like shape , in particular it is signi ficantly longer than it is wide . A filament can easily be stored on a coil and can easily be conveyed over a long distance inside the borehole . Material can be supplied in a constant manner .
[0016] Advantageously, the extrusion material is a polyethylene , in particular a high-density polyethylene (HDPE ) . High-density polyethylene is a thermoplastic polymer with a high strength-to-density ratio . High-density polyethylene provides suf ficient stability for supporting the walls of the borehole .
[0017] In a preferred embodiment , the extrusion unit comprises a cooling unit for cooling the extrusion material . It is arranged inside the extrusion unit such that the cooling unit cools the extrusion material before the extrusion material is melted by the melting unit . The cooling unit prevents the extrusion material from being at least partially melted before the extrusion material is laterally guided . As a result , the filament does not break or lump before entering the melting unit .
[0018] The whole melting process , including the temperature of the extrusion material leaving the melting unit , the volume of the supplied material , can be reliably controlled i f the temperature of the extrusion material entering the melting unit is stabili zed .
[0019] In particular, the cooling unit and the melting unit are spaced from each other . An insulating device , in particular made of titan, is arranged between the cooling unit and the melting unit . An insulation between the heat generating melting unit and the cooling unit improves the ef ficiency of the drilling robot . A cool area and a hot area are clearly separated from each other .
[0020] Advantageously, the melting unit is heated to at least 180 ° C, in particular to at least 200 ° C . Such a high temperature is required to melt high-density polyethylene .
[0021] In particular, a melting channel extending through the melting unit is arranged centrally along the rotational axis of the extrusion unit .
[0022] In a preferred embodiment , the melting channel branches out into several conveying channels that are arranged from the center outwards along the downward end of the melting unit . In particular, the melting channel branches out into at least two conveying channels , in particular at least four conveying channels , in particular at least ten conveying channels , in particular at least twelve conveying channels .
[0023] In particular, the extrusion unit comprises a ring-shaped matrix from where the pipe is extruded . The at least two conveying channels are reunited inside the ring-shaped matrix .
[0024] Separating the melting channel into several conveying channels has the advantage that other components of the drilling robot , in particular other channels , can be arranged between the conveying channels .
[0025] Advantageously, the drilling robot comprises a water-based flushing system for flushing cuttings to the surface , i . e . to the top end of the borehole , through at least one flushing channel . Since the cuttings are generated by the drill head at the lowermost end of the drilling robot , the cuttings have to be flushed past the whole drilling robot from the lower end to the top end and further to the surface of the borehole . Flushing channels are provided inside the drilling robot for conveying the flushed cuttings from the bottom up . At least one flushing channel passes between the at least two conveying channels .
[0026] In particular, the at least one flushing channel has an inner diameter, which is at least two times , in particular at least three times , larger than the inner diameter of the at least two conveying channels . In particular, the flushing channel has an inner diameter of more than 10 mm, in particular of 15 mm . In particular, the inner diameter of the not yet branched melting channel is between 1 . 5 mm and 10 mm, in particular between 1 . 5 mm and 4 mm . Similar dimensions has the extrusion material as a filament .
[0027] Advantageously, the extrusion unit comprises at least one vacuum insulation space thermally insulting the melting unit , in particular thermally insulating the melting unit from the at least one flushing channel . Since water with a temperature of 20-30 ° C is flushed through the flushing channels and the melting unit is heated up to 200 ° C, an ef fective thermal insulation is required .
[0028] Advantageously, the extrusion unit comprises a first expandable balloon, adapted to expand the pipe to its final dimension . In particular, the first expandable balloon has the shape of a torus and it might be made of silicone . The balloon is filled with water or another liquid or gaseous material . It can be retracted by releasing the pressure . Thus , the pipe is expanded to an inner diameter that allows the entire robot to be excavated through the extruded pipe .
[0029] In a preferred embodiment , the extrusion unit comprises a second expandable balloon for insulating the section of the pipe , which is expanded by the first expandable balloon, from water of the water-based flushing system . The section of the pipe being expanded is not yet completely hardened and has to be protected from pollution . The second balloon is pressed against the inner wall of the borehole to ensure an ef fective insulation between the expanding pipe and the water of the flushing system .
[0030] Advantageously, the material feed unit comprises a first rotatable wheel , wherein the first rotatable wheel comprises a rotationally symmetrical recess for conveying the extrusion material as a filament . In particular, the first rotatable wheel is arranged upwards from the melting unit , i . e . the first rotatable wheel conveys the filament before it is fed into the melting unit .
[0031] In a preferred embodiment , the material feed unit comprises a second rotatable wheel , which comprises a rotationally symmetrical recess for conveying the filament . The second rotatable wheel is arranged opposite to the first rotatable wheel , such that the first rotatable wheel and the second rotatable wheel are counter rotating for conveying the filament . Both, the first and the second rotatable wheel act as a dual drive system for conveying the extrusion material as a filament .
[0032] In particular, the first rotatable wheel is powered by a power source . The rotational speed of the first and the second rotatable wheel is controlled by a control unit depending on the locomotion speed of the whole drilling robot inside the borehole . A precise control of the material feed allows to generate a pipe with a constant wall thickness . Extrusion material is not accumulated when the drilling robot stops moving inside the borehole .
[0033] Advantageously, the extrusion unit is spring loaded with respect to the movement unit and / or the extrusion unit comprises a separate movement unit adapted to move the extrusion unit inside the borehole independent of the movement unit of the drilling robot . I f the extrusion unit and the movement unit are not rigidly connected with each other, j erky movements of the movement unit are not directly trans ferred to the extrusion unit but damped .
[0034] In particular, the drilling robot is purely electrically driven .
[0035] Other advantageous embodiments are listed in the dependent claims as well as in the description below .
[0036] Brief Description of the Drawings
[0037] The invention will be better understood and obj ects other than those set forth above will become apparent from the following detailed description thereof . Such description makes reference to the annexed drawings , wherein :
[0038] Fig . 1 shows a general illustration of a system for drilling a borehole ; Fig . 2 shows an overview of the drilling robot working inside the borehole ;
[0039] Fig . 3 shows a side view of the extrusion unit ;
[0040] Fig . 3a to 3e show sectional views of the extrusion unit ; and
[0041] Fig . 4a and 4b show a first and a second explosion drawing of the extrusion unit ;
[0042] Fig . 5 shows an extrusion unit with a second balloon .
[0043] Mode for Carrying Out the Invention
[0044] It follows a description of a speci fic embodiment . The technical data given are merely exemplary and do not limit the scope of the claims .
[0045] Fig . 1 shows a one family house and equipment for drilling a borehole 1 . Borehole 1 is drilled in order to heat the house by geothermal energy . The drilling equipment comprises a drilling robot 2 autonomously operating inside the borehole 1 . I . e . the drill rig is located directly in the borehole 1 and does not require a drill pipe . The drilling robot 2 is connected with a power source and a water source via connection 3 . A container 4 is arranged on the surface 5 for collecting cuttings from the drilling robot 2 . The drilling robot can drill boreholes for geothermal probes up to a depth of at least 250 meters or maximally 500 meters .
[0046] Fig . 2 shows the drilling robot 2 operating inside the borehole 1 in a more detailed view . The drilling robot 2 comprises a drilling unit 6 , a movement unit 7 and a control unit 8 . Furthermore , the drilling robot 2 comprises an extrusion unit 9 extruding a pipe 10 for supporting the borehole 1 . Without such a pipe , rocks , sand, clay etc . would fall into the borehole and cause it to collapse . Pipe 10 is extruded by a filament 20 provided by a material feed unit 11 . The movement unit 7 moves the drilling robot 2 through the borehole 1 . While drilling, the movement unit 7 clamps against the walls of the borehole 1 to absorb all forces of the drilling process . The control unit 8 controls the drilling process of the drilling robot 2 and delivers information to the operating user at the surface 5 .
[0047] A water-based flushing system 12 ef ficiently flushes cuttings 13 to the surface 5 . The water-based flushing system 12 is connected to a water source 14 . The flushing is done by a pump 15 producing a volume flow of about 5 m3 / h at a pressure of 15 bar . The water is then pumped to the surface 5 .
[0048] The water-based flushing system 12 separates the cuttings 13 from the water by a special filter system 16 , which reuses the water for flushing . The separated cuttings 13 are stored in container 4 . Sensors detect the water level , which allows water to either be added or removed .
[0049] The drilling robot 2 is purely electrically driven, powered by a power source 17 and has a cylindrical shape with a diameter Di of 80 mm and a length of about 2 m . The borehole 1 has a diameter D2 of 90 mm .
[0050] Fig . 3 shows a side view of the extrusion unit 9 . Fig . 3a until Fig . 3e show sectional views of the extrusion unit 9 . A filament 20 of high-density polyethylene with a diameter of 5 mm is conveyed from the surface 5 to the extrusion unit 9 . A power source 22 powers a first rotatable wheel 23 and a second rotatable wheel 24 . The second rotatable wheel 24 is arranged directly behind the first rotatable wheel 23 ( see Fig . 3a ) , i . e . opposite to the first rotatable wheel 23 with respect to the filament 20 . The wheels 23 and 24 are counter rotating and comprise a rotationally symmetrical recess 25 for conveying the filament 20 downwards .
[0051] Control unit 8 controls the power source 22 and therefore the rotating speed of the rotatable wheels 23 and 24 . The higher the locomotion speed of the whole drilling robot 2 , the more extrusion material per time unit has to be fed into the extrusion unit for extruding pipe 10 . The rotating speed of the rotatable wheels 23 and 24 is controlled depending on the locomotion speed of the drilling robot inside borehole 1 .
[0052] The extrusion unit 9 comprises a melting unit 26 , a cooling unit 27 and an insulating device 28 thermally insulating the melting unit 26 from the cooling unit 27 . The melting unit 26 is a metal block, comprising heating cartridges 29 to heat the melting unit 26 up to 200 ° C for melting the filament 20 conveyed through the vertically oriented melting channel 21 inside the melting unit 26 . The temperature of the melting unit 26 is controlled by temperature sensors 30 .
[0053] The cooling unit 27 arranged above the melting unit 26 prevents the filament 20 from melting before entering the melting unit 26 . An aluminium body comprises a plurality of lamellae extracting thermal energy from the filament 20 . The insulating device 28 is a sleeve made of titan surrounding the filament between the melting unit 26 and the cooling unit 27 . The insulating device 28 spaces the melting unit 26 from the cooling unit 27 .
[0054] Downstream of the melting unit 26 , a melting channel is tri furcated into conveying channels 31 . Those conveying channels 31 are then bi furcated twice more into totally twelve conveying channels 31 and reunited inside a ring-shaped matrix 32 from where the pipe 10 is extruded . The twelve conveying channels 31 and the reunited ring-shaped matrix 32 are well visible in Fig . 3e .
[0055] Extrusion is carried out by pressing the liquefied high-density polyethylene through the outlet ring 33 upwards along a heated mandrel 34 . An expandable first balloon 35 having the shape of a torus and made of silicone is filled with water and forms an intermediate space 36 between the first balloon 35 and the inner wall 37 of the borehole 1 . The liquefied high-density polyethylene is pressed through the intermediate space 36 , cools down and hardens to pipe 10 .
[0056] As already described with respect to Fig . 2 , the drilling robot 2 comprises a water-based flushing system 12 ef ficiently flushing cuttings 13 to the surface 5 . The extrusion unit 9 comprises three flushing channels 38 conveying the water with cuttings 13 upwards through the extrusion unit 9 into pipe 10 . The flushing channels
[0057] 38 have a diameter of 15 mm and are arranged between the conveying channels 31 .
[0058] Vacuum insulation spaces 39 surround the melting unit 26 and are arranged between the melting unit 26 and the flushing channels 38 . Vacuum insulation spaces
[0059] 39 insulate the hot melting unit 26 from the flushing channel 38 conveying water on a temperature only between 20 ° and 30 ° C . The vacuum insulation space 39 is sealed by vacuum sealings 40 , a lower insulation plate 41 , an upper insulation plate 42 and it can be evacuated by sucking air out of the vacuum insulation space 39 through a vacuum suction opening 43 .
[0060] Fig . 4a and 4b show a first and a second explosion drawing of the extrusion unit .
[0061] Fig . 5 shows an improved embodiment of the extrusion unit 9 . It additionally comprises a second expandable balloon 44 . The second expandable balloon 44 protects the section above the second balloon 44 , where pipe 10 is extruded, from water of the water-based flushing system 12 below the second balloon 44 .
[0062] As shown in Fig . 2 , the extrusion unit 9 is connected with the movement unit 7 via spring 45 to damp j erky movements of the movement unit 7 . Additionally, the extrusion unit 9 can have a separate movement unit 46 for moving the extrusion unit 9 independently of the movement unit 7 . Borehole
[0063] Drilling robot Connection Container Surface
[0064] Drilling Unit
[0065] Movement unit Control unit Extrusion unit Pipe
[0066] Material feed unit
[0067] Water-based flushing system Cuttings Water source Pump
[0068] Filter system
[0069] Power source at the surface Filament
[0070] Melting channel
[0071] Power source of the rotatable wheels First rotatable wheel
[0072] Second rotatable wheel Rotationally symmetrical recess Melting unit Cooling unit
[0073] Insulating device Heating cartridges Temperature sensors Conveying channels
[0074] Ring-shaped matrix
[0075] Outlet ring
[0076] Heated mandrel First balloon Intermediate space Inner wall of the borehole
[0077] Flushing channels
[0078] Vacuum insulation spaces
[0079] Vacuum sealings
[0080] Lower insulation plate Upper insulation plate Vacuum suction opening Second balloon
[0081] Springs
[0082] Separate movement unit
Claims
Claims1. Drilling robot (2) for drilling a borehole (1) comprises- a movement unit (7) for moving and stabilizing the drilling robot (2) inside the borehole (1) ,- a drilling unit (6) for generating the borehole ( 1 ) ,- an extrusion unit (9) for producing a pipe (10) within the borehole (1) to support the borehole (1) ,- a material feed unit (11) feeding extrusion material into the extrusion unit (9) , characterized in that the extrusion unit (9) comprises a melting unit (26) for melting the extrusion material .
2. Drilling robot (2) according to claim 1, wherein the extrusion material fed into the extrusion unit (9) is a filament (20) .
3. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion material is a plastic, in particular a thermoplastic.
4. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) comprises a cooling unit (27) for cooling the extrusion material .
5. Drilling robot (2) according to claim 4, wherein the cooling unit (27) is arranged inside the extrusion unit (9) such that the cooling unit (27) cools the extrusion material before the extrusion material is melted by the melting unit (26) .
6. Drilling robot (2) according to claim 4 or5, wherein the cooling unit (27) and the melting unit(26) are spaced from each other, wherein an insulating device (28) , is arranged between the cooling unit (27) and the melting unit (26) .
7. Drilling robot (2) according to any one of the preceding claims, wherein the melting unit (26) is heated to at least 120°C, in particular at least 180°C, in particular to at least 200°C.
8. Drilling robot (2) according to any one of the preceding claims, wherein a melting channel (21) extending through the melting unit (26) branches out into at least two conveying channels (31) that are arranged along the downward end of the melting unit, in particular branches out into at least four conveying channels (31) , in particular at least ten conveying channels (31) , in particular at least twelve conveying channels (31) .
9. Drilling robot (2) according to claim 8, wherein the extrusion unit (9) comprises a ring-shaped matrix (32) from where the pipe (10) is extruded, wherein the at least two conveying channels (31) are reunited inside the ring-shaped matrix (32) .
10. Drilling robot (2) according to any one of the preceding claims, comprising a water-based flushing system (12) for flushing cuttings (13) to the surface (5) through at least one flushing channel (38) .
11. Drilling robot (2) according to claim 8 or 9 and according to claim 10, wherein the at least one flushing channel (38) passes between the at least two conveying channels (31) .
12. Drilling robot (2) according to claim 11, wherein the at least one flushing channel (38) has a diameter, which is at least two times, in particular atleast three times, larger than the diameter of the at least two branches (31) .
13. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) comprises at least one vacuum insulation space (39) and / or at least one air insulation space and / or at least one foam insulation space thermally insulting the melting unit (26) .
14. Drilling robot (2) according to any one of the claims 10 to 12 and according to claim 13, wherein the vacuum insulation space (39) insulates the melting unit (26) from the at least one flushing channel (38) .
15. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) comprises a first expandable balloon (35) , adapted to expand the pipe (9) into its final dimension.
16. Drilling robot (2) according to claim 15, wherein the first expandable balloon (35) has the shape of a torus.
17. Drilling robot (2) according to claim 15 or 16, wherein the first expandable balloon (35) is made of silicone.
18. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) comprises a second expandable balloon (44) for insulating that section of the pipe (10) , which is expanded by the first expandable balloon (35) , from water of the waterbased flushing system (12) .
19. Drilling robot (2) according to claim 2 and according to any one of the preceding claims, whereinthe material feed unit (11) comprises a first rotatable wheel (23) , wherein the first rotatable wheel (23) comprises a rotationally symmetrical recess (25) for conveying the filament.
20. Drilling robot (2) according to claim 19, wherein the material feed unit (11) comprises a second rotatable wheel (24) , wherein the second rotatable wheel (24) comprises a rotationally symmetrical recess (25) for conveying the filament, and is arranged opposite to the first rotatable wheel (23) , such that the first rotatable wheel (23) and the second rotatable wheel (24) are counter rotating for conveying the filament.
21. Drilling robot (2) according to claim 19 or claim 20, wherein the first rotatable wheel (23) is powered by a power source (22) .
22. Drilling robot (2) according to claim 21, wherein the rotational speed of the first rotatable wheel (23) is controlled by the control unit (8) , adapted such that the rotational speed is controlled depending on the locomotion speed of the drilling robot (2) relative to the borehole (1) .
23. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) is spring loaded with respect to the movement unit.
24. Drilling robot (2) according to any one of the preceding claims, wherein the extrusion unit (9) comprises a separate movement unit (46) adapted to move the extrusion unit (9) inside the borehole (1) independent of the movement unit (7) of the drilling robot (2) .
25. Drilling robot (2) according to claim 2, wherein the extrusion material as a filament (20) has adiameter between 1.5 mm and 10 mm, in particular between 1.5 mm and 4 mm.
26. Drilling robot (2) according to any one of the preceding claims, wherein the drilling robot (2) is purely electrically driven.