Drilling equipment and its use in liquid storage tanks

Abstract

The present invention relates to a drilling apparatus for drilling holes in walls, the drilling apparatus comprising a cylindrical cap portion (12) and a drill sleeve (13), the cylindrical cap portion being fixed around a longitudinal portion of a drill bit (11) and having a diameter D, wherein when drilling a wall (6, 8, 10a, 10b), the cap portion (12) slides in the drill sleeve at least over a length L, the drill sleeve (13) and the cap portion (12) being mounted with a sliding fit H7g6 as defined in standard ISO 8015, and the coefficient of friction between the drill sleeve (13) and the cap portion (12) being at most equal to 0.2 (a coefficient that can be measured by a standardized method according to standard ASTM G77), and the guide distance L of the cap portion (12) being guided in the drill sleeve (13) being at least equal to 2.5 times the diameter of the cap portion (12), in other words, L≥2.5D.

Description

Technical Field

[0001] The present invention is most widely accepted as relating to drilling in concrete structures or the like, and more particularly to the field of tanks for storing liquefied gases, liquefied natural gas or the like, particularly tanks for ground storage of liquefied natural gas (referred to as ground storage tanks (GST)) and natural gas storage tanks submerged in the ocean (referred to as gravity based support (GBS)). Background Technology

[0002] The invention is described below in the context of a GST structure, but this is a completely non-limiting description concerning the drilling equipment according to the invention, its application fields or uses.

[0003] Liquefied natural gas (LNG) is typically transported at sea in storage tanks mounted on transport ships. The natural gas is kept in a liquid form to maximize the amount of gas that can be transported in each tank; one liter of liquid natural gas has a much smaller volume than one liter of gaseous natural gas. These storage tanks maintain the LNG at very low temperatures, more precisely, below -163°C, at which temperature the natural gas is liquid under atmospheric pressure.

[0004] For loading and / or unloading tanks from these LNG carriers, LNG surface storage tanks (GSTs) are typically installed in ports. These GSTs are generally configured to allow LNG carriers to replenish and / or unload LNG cargo. Such surface storage tanks are equipped with elements (e.g., pipelines) that penetrate one of the walls of these tanks, thereby enabling communication between the LNG loading and / or unloading facilities and the internal volume of the surface tank storing the LNG.

[0005] Such storage tanks require internal facilities that enable the cryogenic liquid to be held substantially in liquid form, while also being completely sealed and insulated. Such internal facilities are known, in particular, from the applicant's published documents, of storage tanks used to form GST-type tanks.

[0006] However, these GST or GBS tanks consist of very hard or solid concrete walls, requiring holes to be drilled to a certain depth in order to secure the sealing insulation to the concrete walls, specifically by using studs.

[0007] The applicant has found that the holes currently being drilled are not satisfactory because, on the one hand, it is difficult to drill perfectly orthogonal or perpendicular to the tank wall, and on the other hand, the vapor barrier surrounding the holes is frequently damaged. The applicant has also found that, in terms of hole placement, good accuracy—i.e., within + / - 1.5 mm—is difficult to achieve with existing tools.

[0008] It should be noted that if the hole is not perfectly orthogonal to the wall, this will cause problems when installing the sealing insulation and will significantly reduce the operational durability of the sealing insulation.

[0009] In addition, a vapor barrier layer is typically present on the inner wall of such tanks to prevent concrete from contacting water and to ensure good adhesion to the adhesive, which is essential for the sealed insulation to support the concrete wall. Specifically, the installation of the insulation system must ensure a seal: on the one hand, relative to the nitrogen (N2) contained within the insulation space, and on the other hand, relative to the outside atmosphere, preventing oxygen from migrating into the insulation space. Summary of the Invention

[0010] After various experiments and tests, the applicant has developed a drilling device that can drill holes to relatively large depths in hard or very hard walls (such as concrete or the like) without any deviation of the drill bit and the drill head, such that the hole formed is perfectly orthogonal to the wall throughout its entire depth.

[0011] In fact, with the drilling device according to the invention, the drill bit and the drill head of the drill bit do not experience any vibration or almost no vibration, or any bending during drilling.

[0012] Therefore, the present invention relates to a drilling apparatus for drilling holes in walls, the drilling apparatus comprising a body housing at least one drill bit made of metal or metal alloy, the drill bit having a drill head at one end capable of drilling holes in walls, the apparatus having a power source and / or adapted to be connected to an electrical supply.

[0013] The present invention is characterized in that the drilling equipment further includes:

[0014] - A cylindrical cap portion, which is fixed around the longitudinal portion of the drill bit, has a diameter;

[0015] - Drill casing, when drilling a hole in the wall, the cap sleeve slides at least along length L.

[0016] The drill casing and cap sleeve are installed with a sliding fit H7g6 as defined in standard ISO 8015, and

[0017] The coefficient of friction between the drill casing and the cap sleeve is at most 0.2 according to standard ASTM G77.

[0018] Preferably, the guiding distance L by which the cover cylinder part is guided in the drill casing is at least equal to two and a half times the diameter of the cover cylinder part, in other words L≥2.5D.

[0019] Therefore, after multiple tests and analyses, the applicant has developed a drilling device that does not require additional components / supplementary components, and all the elements required for drilling are included in the drilling device, and the holes are completely orthogonal throughout the entire depth of each hole. Thus, a single operator has all the necessary functional elements, and since the drilling device according to the invention weighs only a few kilograms, a single operator can operate such a device.

[0020] It should be noted here that the holes typically required in the wall of a GST or GBS tank are at least 40 millimeters (mm), typically about 50 mm, so that a wall plug or the like can be inserted into the hole.

[0021] The applicant has also demonstrated that due to the elimination or very significant reduction of vibrations from the drill bit, it is possible to drill holes in all types of walls (including very hard walls, such as concrete walls) without any deviation at the drill head part. In other words, the drilling device according to the invention is a device that eliminates vibrations, instability or bending of the drill bit and the drill head part of the drill bit.

[0022] The term "drill bit" or "drill head part" is understood to mean a drill bit used for forming a hole or machining a hole.

[0023] By convention, the terms "outer" and "inner" are used to define the relative position of one element with respect to another element in reference to the interior and exterior of the storage tank. Thus, when the drilling device is arranged against the wall, the drill bit has two ends, an outer end that carries the drill head part and an inner end that carries a stop flange, which will be described in more detail below.

[0024] The following briefly describes other advantageous features of the present invention:

[0025] Advantageously, the cylindrical cover cylinder part is made of metal or metal alloy, preferably the cylindrical cover cylinder part is made of bronze.

[0026] In this case, it should be noted that the drill bit is advantageously made of an iron-based alloy of the type that by weight includes the following: 0%<C<0.21%, 0%<Mn<1%, 0%<Si<0.5%, 0%<P<0.035% and 0%<S<0.035%, with the remainder being iron and impurities inevitably produced in production.

[0027] By convention, considering the elements of the Mendeleev table, namely:

[0028] C: carbon; Mn: manganese; Si: silicon; P: phosphorus and S: sulfur.

[0029] Typically, the cap and drill casing must have a very low coefficient of friction, at most 0.2 according to ASTM G77, preferably at most 0.15. Therefore, if the drill casing is made of steel and the cap is made of bronze, the coefficient of friction is approximately 0.15, roughly equivalent to a steel / steel combination. However, bronze is a self-lubricating material, a characteristic particularly advantageous for drilling equipment and its drilling function.

[0030] It should be noted that, in this case, particularly if a material other than bronze is used to form the cap section, the drilling equipment according to the invention may optionally include a conventional lubrication device approved for use on the outer surface of the cap section and / or the inner surface of the drill casing, so as not to contaminate the tank and its contents. Attention must still be paid to using approved lubricants that do not contaminate the tank and its insulation technology.

[0031] It should be noted that, in this case, self-lubricating materials are preferably used for the cap and the drill sleeve to prevent any dust from entering between the cap and the drill sleeve, which could cause premature wear of these two components.

[0032] It should also be noted that the cap sleeve may also be made of polymer or even composite material, with the outer surface of the cap sleeve close to the drill casing and having little or no fiber or similar material.

[0033] As described above, due to the standard relative friction and assembly characteristics between the cap sleeve and the drill sleeve, drilling is optimal via the drill bit, which will not bend, and the absorption of vibrations generated by the drill bit during drilling of walls made of concrete or the like is optimal, so that the operator will not experience any parasitic forces or discomfort during drilling, resulting in the drilled hole being exactly perpendicular to the wall as required for the installation of wall plugs / studs, which are used for the installation / assembly of sealing insulation facilities.

[0034] Preferably, the main body accommodates multiple drill casings, and more preferably, the main body accommodates at least six drill casings.

[0035] This feature of the drilling apparatus according to the invention enables the drilling of multiple holes without having to move the apparatus against the wall.

[0036] According to a specific advantageous feature of the invention, the drill bit / cap assembly is removably mounted in the drill sleeve, such that the operator arranges / positions the main body against the wall with the drill sleeve facing the hole to be drilled, and then the drill bit / cap assembly is inserted into the drill sleeve. As shown below, before inserting the drill bit together with its cap, the operator can check the correct positioning of the equipment relative to the hole to be drilled by observing through a hole in the drill sleeve.

[0037] In the context of this particular feature of the invention, the drill casing is advantageously movably mounted on the body in pairs via an insertion portion, the body preferably including means for measuring the distance between each pair of drill casings.

[0038] Therefore, preferably, drill casings are mounted in pairs on a plate, the plate being pre-drilled to receive the drill casings. The plates are assembled by sliding on a body so that each plate can move linearly, and thus each pair of drill casings can move linearly. A measuring device enables precise positioning of each plate at a desired location, thereby positioning each pair of casings at a desired location.

[0039] The paired installation of drill casings corresponds to a specific feature of GST or GBS tanks, where paired studs—two studs located at a predetermined distance from each other—are common. Furthermore, the fact that these paired drill casings are movable relative to each other on the main body of the drilling equipment provides maximum adaptability and flexibility to the equipment, thus saving time for the operator.

[0040] Advantageously, the body is constructed of a plate made of metal and / or polymer or composite material, and preferably, the body is constructed of an aluminum plate. In the context of this invention, the term "plate" refers to a shaped segment made of a material (advantageously, metal, preferably aluminum).

[0041] It should be noted that in this case, the plate present on the body is advantageously made of metal, such as aluminum similar to the body, or of another material (e.g., steel).

[0042] As mentioned above, this body is particularly lightweight while providing sufficient rigidity and mechanical strength for its use.

[0043] Advantageously, the drilling equipment includes a system for suctioning dust generated through the borehole.

[0044] In particular, this suction prevents any accumulation of dust and any interference with the sliding or movement of the cap section within the drill casing. The suction also prevents contamination of the tank and its contents.

[0045] Preferably, the dust extraction system comprises: a chamber, which is preferably removably fixed to the drill casing; and a pipe leading to the chamber for extracting and discharging dust.

[0046] The practical embodiment described in more detail below enables optimal removal of dust generated by drilling into concrete, ensuring that the drilling equipment is not damaged during operation and that the operator does not experience any visual or respiratory discomfort during drilling.

[0047] Within the scope of this advantageous embodiment, preferably, the suction system is of a conventional type, and more specifically includes a conventional pump. In the context of this invention, the term "conventional pump" is understood to mean, for example, a construction pump. Preferably, the conventional pump is not a Venturi effect type pump.

[0048] Advantageously, the body includes a device for fixing it to the wall. It is important to remember that the device for fixing it must not compromise the integrity of the vapor barrier.

[0049] According to one possibility provided by the invention, the device for fixing to a wall consists of at least one suction cup, preferably multiple suction cups, which preferably operate by suction of the Venturi effect type.

[0050] Advantageously, the discharge section of the pump or venturi tube must include a filter to prevent any risk of contamination of the tank and its insulation system due to particles of water or oil contained in the compressed air.

[0051] Preferably, the discharge section of the pump or venturi tube includes a silencer to reduce noise that might irritate the operator.

[0052] Because GST or GBS type canisters typically have a pressurized gas (compressed air) network and / or such a pressurized gas network, the partial vacuum generated by the Venturi effect is advantageous, and this is particularly suitable for installing / assembling such canisters, given that the installation / assembly of such canisters does not involve the use of flammable / explosive fluids.

[0053] In the context of this invention, a suction section via the Venturi effect typically includes a main line having an inlet and an outlet adapted to be connected to a pressurized gas source, the suction line having an upstream end and a downstream end, the upstream end being adapted to be connected to the outlet port of the suction system of a drilling device, and the downstream end extending laterally to a converging-diverging section of the main line, such that the gas flow in the main line generates a negative pressure in the suction line.

[0054] Of course, the suction system can also consist of conventional pumps (in other words, not Venturi effect pumps) operated by a power supply. The suction system can also be configured to include one or more pumps referred to as conventional pumps and one or more Venturi effect pumps, which can operate together or otherwise as desired by the operator performing the operation in relation to ambient conditions and / or other factors.

[0055] Preferably, the cap sleeve includes a stop flange at the end of the cap sleeve opposite to the drill bit, the stop flange restricting the movement of the cap sleeve in the drill casing.

[0056] Preferably, the drill casing is removably and movably mounted in the body to adjust the distance from the casing to the wall, and the device preferably includes at least one clamping collar for the drill casing to hold the casing in place at a desired distance from the wall.

[0057] The flange of the cap sleeve, together with the movement of the drill sleeve and the fixing of the drill sleeve by the clamping collar, constitute a simple, inexpensive, and effective mechanical device, allowing for operation regardless of the depth of the hole to be drilled and / or the surface roughness of the wall (see, for example...). Figure 8 ,exist Figure 8 (As can be seen from the uneven wall), it can provide perfect adaptability for drilling equipment.

[0058] According to another possibility provided by the invention, the drilling equipment further includes an independent positioning element for positioning the body on the wall for drilling.

[0059] The fact that the positioning element is composed of a component independent of the main body allows for the separation of the purpose or function of arranging or positioning the hole to be drilled from the main drilling function belonging to the main body. Therefore, firstly, the positioning element is arranged and fixed to the wall relative to a mark present on the wall to position the hole; secondly, the main body is added and fixed to the positioning element. This method allows for better reliability in the positioning and location of the hole to be drilled. It should be noted that the operator can additionally check the positioning or actual location of the hole to be drilled by observing it through the drill casing, at which stage the drill casing does not contain the drill bit / cap assembly.

[0060] Of course, as a variation, it is also conceivable that the main body itself has a device for positioning and arranging the drill bit for drilling at a selected location on the wall.

[0061] Preferably, the independent positioning element for positioning the main body includes a means for fixing it to the wall, and the means for fixing is preferably composed of a suction cup-shaped portion having a Venturi effect type of suction.

[0062] The present invention also relates to a system for drilling holes in the walls of a liquid storage tank made of concrete or the like, the system comprising:

[0063] - A storage tank, preferably of type GBS or GST, for storing liquids, the tank comprising at least one wall made of concrete or the like; and

[0064] -The drilling equipment briefly described above.

[0065] Finally, the present invention relates to drilling holes in the walls of liquid storage tanks made of concrete or the like using the drilling equipment described above in a brief description, wherein the liquid storage tanks are preferably GBS or GST type storage tanks. Attached Figure Description

[0066] The invention will be more clearly understood from the following description of several specific embodiments of the invention, provided only by way of non-limiting illustration, and with reference to the accompanying drawings, and other objects, details, features, and advantages of the invention will become clearer.

[0067] [ Figure 1 ] Figure 1 This is a perspective view of the GST tank (in other words, the ground storage tank).

[0068] [ Figure 2 ] Figure 2 This is a schematic cross-sectional view of the drill casing, drill bit, and barrel according to the invention, facing the wall.

[0069] [ Figure 3 ] Figure 3 Is with Figure 2 The same view, in Figure 2 In the middle, the drill bit has penetrated the wall to the end of its stroke.

[0070] [ Figure 4 ] Figure 4 This is a schematic cross-sectional view of the drill casing, drill bit, and cylinder according to the present invention, with the drill casing and drill bit / cap cylinder assembly shown separately.

[0071] [ Figure 5 ] Figure 5 This is a schematic top view of the main body of the drilling equipment according to the present invention;

[0072] [ Figure 6 ] Figure 6 yes Figure 5 The diagram shows a cross-sectional view of the main body, in which a drill bit is drilling a hole in the wall.

[0073] [ Figure 7 ] Figure 7 yes Figure 5 The schematic diagram of the transverse cross-section of the main body shows the possible movement of the drill casing and the clamping collar of the drill casing for maintaining the desired position.

[0074] [ Figure 8 ] Figure 8 Is with Figure 5 The schematic diagram shows a cross-section of a main body that is substantially the same as the main body, with particular emphasis on the chambers located on each drill casing for dust extraction.

[0075] [ Figure 9 ] Figure 9 Is with Figure 5The schematic diagram of the transverse cross section of the main body, which is substantially the same as the main body shown, particularly shows the retaining ring for holding one or more drill casings in place for the drilling apparatus according to the invention.

[0076] [ Figure 10 ] Figure 10 It is a schematic top view of the main body arranged against the wall, along with the elements used to position the main body for drilling holes in the correct location on the wall.

[0077] [ Figure 11 ] Figure 11 Is with Figure 10 The same view as the view in which the positioning element is fixed to the body, so that the drilling equipment is ready to drill holes in the correct position on the wall. Detailed Implementation

[0078] In this context, the term "vertical" refers to extension in the direction of the Earth's gravitational field. The term "horizontal" refers to extension in a direction perpendicular to the vertical direction. The longitudinal direction corresponds to the main extension direction of the sealed insulated tank, which is parallel to the longitudinal axis L of the coordinate system (L, V, T) shown in the accompanying drawings. The transverse direction corresponds to a direction parallel to the transverse axis along which the end walls of the sealed insulated tank extend primarily, parallel to the transverse axis T of the coordinate system (L, V, T), and perpendicular to the longitudinal axis L. Finally, the vertical direction corresponds to a direction parallel to the vertical axis V of the coordinate system (L, V, T), which is perpendicular to both the longitudinal axis L and the transverse axis T.

[0079] Figure 1 A generally rectangular parallelepiped-shaped, sealed, insulated tank 1 is shown, which may be constructed from a GST tank. Tank 1 includes a storage structure 2 and a support structure 4 surrounding the storage structure 2. The storage structure 2 is configured to contain and / or store fluids, more particularly cryogenic liquids such as liquefied natural gas or liquefied petroleum gas. The storage structure 2 includes multiple walls resting against the support structure 4. When tank 1 is at least partially filled with the fluid, the support structure is configured to support the multiple walls, with the fluid exerting pressure on each of the multiple walls.

[0080] According to a non-limiting example, this type of tank 1 is used in a surface storage unit for liquefied natural gas (LNG), which serves as a loading and / or unloading point for marine transport vessels (e.g., gravity platforms (GBS tanks)). A "gravity platform" refers to a tank that is at least partially underwater, for example in a port, and where liquefaction and / or gasification units are mounted on the ceiling of the tank. More specifically, tank 1 can interact with the liquefaction and / or gasification units, such that the tank stores liquefied gas from the liquefaction units and / or supplies liquefied gas to the gasification units.

[0081] like Figure 1 As shown, tank 1 extends primarily in the longitudinal direction L. The storage structure 2 includes multiple walls, including a ceiling wall 6 and a bottom wall 8, each extending generally in a plane parallel to the longitudinal direction L and the transverse direction T, with the transverse direction T perpendicular to the longitudinal direction L. The storage structure 2 also includes multiple side walls 10a, 10b, extending at least between the bottom wall 8 and the ceiling wall 6 in a vertical direction V, perpendicular to both the longitudinal direction L and the transverse direction T. In this case, the multiple side walls 10a, 10b include two longitudinal walls 10a parallel to each other and two end walls 10b parallel to each other. The longitudinal walls 10a extend in the longitudinal direction L, and the end walls 10b extend in the transverse direction T between the two longitudinal walls 10a.

[0082] Walls 6, 8, 10a, and 10b include a vapor barrier layer designed to prevent the concrete from contacting water. This vapor barrier layer also ensures good adhesion to the adhesive used to support the sealing insulation installed in GST tank 1. This vapor barrier layer is typically made of glass fiber reinforced epoxy resin and must not be damaged by any failure to perform the aforementioned functions. This is why installation / assembly operations (especially drilling operations) must not damage this vapor barrier layer.

[0083] The support structure 4 adopts the shape of the storage structure 2 and surrounds the storage structure 2. For this purpose, the support structure 4 includes a plurality of partitions 9, each of which advantageously extends parallel to one of the plurality of walls.

[0084] This invention relates to an apparatus for drilling holes in walls (e.g., walls 6, 8, 10a, and 10b of a GST tank 1), but the invention is not limited in any way to this type of tank or even to walls 6, 8, 10a, and 10b of this type. However, it should be noted that the applicant has already manufactured such drilling equipment primarily to address problems associated with holes currently drilled in these GST or GBS tanks, making certain features of the invention advantageously applicable to these types of structures.

[0085] Figure 2The main components of the drilling apparatus according to the invention are shown: a drill bit 11 having a drill head 11', a cap portion 12 fixed around the drill bit 11, and a drill sleeve 13, the assembly formed by the drill bit 11 and its cap portion 12 sliding within the drill sleeve. In the context of the invention, these three components 11, 12, and 13 are always present for each drilling unit included in the drilling apparatus 30 according to the invention. It should be understood that the drilling apparatus 30 advantageously includes multiple drilling units 11, 12, and 13, such that maximum drilling is performed once the apparatus 30 has been positioned and fixed to the walls 6, 8, 10a, or 10b.

[0086] This diagram describes the following dimensions:

[0087] L2: The working length of drill bit 11, in other words, the length of drill bit 11 protruding outside the cover portion 12 that can be used to drill holes in walls 6, 8, 10a, or 10b. In this case, L2 is at least equal to 60 mm, thus accommodating, with an additional safety length, the holes typically drilled in walls 6, 8, 10a, or 10b of the GST tank 1. Naturally, for another storage structure, this distance L2 can be specified to be much larger, or alternatively smaller.

[0088] D: Diameter of the cap cylinder 12. A key feature of the invention is the sliding fit H7g6 between the cylinder 12 and the drill casing, as defined in standard ISO 8015.

[0089] In practice, this embodiment means that if the diameter D of the cover portion 12 is approximately 60 mm, then the diameter D of the cover portion 12 is actually within the range of the following inequality:

[0090] (60-0.029)≤D 盖筒部 ≤(60-0.01)

[0091] Although the diameter is approximately 60 mm, the diameter D of the drill casing 13 is actually within the range of the following inequalities:

[0092] (60+0)≤D 钻套管 ≤(60+0.030)

[0093] L3: The insertion length of the cap sleeve 12 into the drill sleeve 13. At the start of the stroke, if... Figure 3 As shown, when the flange 14 of the cover sleeve 12 has come into contact with the drill sleeve 13, the insertion length L3 is at least equal to the length L, in other words, two and a half times the diameter D: L≥2.5D.

[0094] Note that in this case, the cap portion 12 is secured to the drill bit 11 by any mechanical and / or physicochemical means. In the example chosen for illustrating the invention, the cap portion 12 is secured to the drill bit 11 by welding.

[0095] Therefore, the cap sleeve 12 includes a stop flange 14 that functions to limit the travel of the sleeve 12 within the drill casing 13. As described above, the travel L of the cap sleeve 12 within the drill casing 13 is at least equal to 2.5 times the diameter D. Thus, the cap sleeve 12 is guided at a sufficient distance with a sliding fit H7g6 according to standard ISO 8015, such that vibrations are attenuated or even completely eliminated during drilling, and that bending or deviation of the drill bit 11 and its drill head 11' is minimized or even eliminated.

[0096] As in Figures 2 to 4 As can be seen, the drill casing 13 abuts against the walls 6, 8, 10a or 10b via a gasket 15. The gasket is made of a material that will not damage the vapor barrier layer present on the walls 6, 8, 10a or 10b, such as polymer foam or rubber / elastomer.

[0097] exist Figure 4 In this case, the drill sleeve 13 also includes a support flange 14' for abutting against the flange 14 of the cap sleeve 12. However, such a support flange 14' is optional, provided that the surface of the drill sleeve 13 facing the stop flange 14 is sufficient to repeatedly support the stop flange 14 without damaging the surface or either of the stop flange.

[0098] As in Figure 9 As can be seen, the drill sleeve 13 advantageously has a groove in which the retaining ring 34 is received. Therefore, when the drilling equipment 30 is arranged in an inverted manner, for example when drilling a hole in the ceiling wall 6, the drill sleeve 13 will not fall out of the insertion portion 16 when the retaining collar 22 is released.

[0099] Figures 5 to 10 An embodiment of a drilling apparatus 30 according to the invention is shown. In this embodiment, the drilling apparatus 30 includes four pairs of drill sleeves 13 into which four pairs of drill bits 11, 11' can be inserted respectively. Note that in this case, the drilling apparatus 30 according to the invention typically uses a single, individual drill bit 11 provided with a cap portion 12, which is successively inserted into various holes in the body 17 to perform drilling operations. Each pair of drill sleeves 13 is mounted on an insertion portion 16, which is fixed to the body 17 of the drilling apparatus 30. In this case, the body 17 is constructed of a rectangular strip or plate made of a strong, lightweight material (e.g., aluminum), and each insertion portion 16, also advantageously made of aluminum, is movably fixed along the longitudinal axis x'x of the body 17.

[0100] Each insert 16 is fixed to the body 17 approximately at its midpoint, such that each drill sleeve 13 is positioned on either side of the longitudinal axis x'x at approximately equal distances from the axis x'x, with the insert 16 extending along the vertical axis x'x. This arrangement of the drill sleeves 13 on the body 17 and the overall shape of the body 17 are particularly suitable for drilling holes in the walls 6, 8, 10a, or 10b of ground tanks (especially GST or GBS) for cryogenic liquids; however, naturally, the relative positioning of the body 17 and the drill sleeves 13 can be different and adapted to the structure of the hole to be drilled.

[0101] Furthermore, the main body 17 includes a scale system 18 for measuring the distance between the two insertion portions 16, thereby positioning the insertion portions at a desired relative distance. Specifically, each insertion portion 16 is movably mounted on the main body 17 along the axis x'x, allowing the operator to position each insertion portion 16 at a predetermined distance from each other, corresponding to a hole to be drilled in the walls 6, 8, 10a, or 10b.

[0102] The drilling equipment 30 has a device for fixing to walls 6, 8, 10a, or 10b. In this case, the device consists of a suction cup 19, which is fixed approximately at the center of the body 17 to ensure a good distribution of the force for fixing to the wall at the center of gravity of the body 17. Of course, multiple suction cups 19 can be provided, and the arrangement of these suction cups 19 depends primarily on the efficiency criteria for the actual use of the drilling equipment 30 by the operator (preferably a single operator). In a particularly advantageous manner, the suction cup 19 operates by suction (more precisely, by the Venturi effect); the suction cup 19 (more specifically, the suction chamber of the suction cup) is connected to a compressed gas circuit via a conduit 20 or the like, thereby creating the partial vacuum required for suction. It should be noted again that this Venturi suction system is particularly suitable for sensitive areas storing flammable or explosive materials, such as GST or GBS. Finally, the dimensions of the suction cup 19 and the suction system of the suction cup are such that once attached to the wall, it can maintain a weight of at least twenty-five (25) kilograms. At the suction cup 19, suction is cut off and activated by a rod 21, button or the like located on the body 17.

[0103] Figure 7A clamping collar 22 for the drill sleeve 13 is shown in particular. Each drill sleeve 13 is thus threaded or fitted into a dedicated hole in the insertion portion 16, which itself is fixed to the body 17, and the height or distance of each drill sleeve 13 can be adjusted by the clamping collar 22. Therefore, depending on the depth of the hole to be drilled and / or the surface condition of the wall, the drill sleeve 13 is positioned such that the supporting flange 14' of the drill sleeve is at a given distance from the body 17. Thus, when the cap portion 12 with drill bits 11, 11' is inserted into the drill sleeve 13, the stop flange 14 of the cap portion 12 blocks the travel of the drill bits 11, 11' at the desired depth of the hole to be drilled. Note that in this case, the drilling device 30 according to the invention is both simple and effective, and all parts or elements 11, 12, 13, 19, 22 are removable and can therefore be replaced with new parts or elements of different shapes and / or different sizes, or simply with new parts or elements to replace worn parts or elements.

[0104] Figure 8 A system for suctioning dust when drilling holes in walls 6, 8, 10a, or 10b is specifically shown. In the embodiment chosen to illustrate the invention, the dust suction system includes a chamber 25 formed by an enclosure, which is advantageously conical, surrounding at least along the length L2 of the drill bit 11 at its end, and is advantageously removably secured to the drill sleeve 13. The chamber 25 can be made of any material that is flexible and sufficiently robust to structurally withstand the suction generated or formed within the chamber 25. Unlike the suction cup 19, the dust suction system advantageously uses a conventional industrial vacuum cleaner (not shown in the figures).

[0105] The suction chamber 25 allows for the suction of dust and is calibrated according to the desired hole depth. The drill sleeve 13 is positioned on this chamber to obtain the correct height for drilling the desired hole.

[0106] Advantageously, the O-ring 33 is integrated at the end of the cap portion of the drill bit 11 to prevent any dust from entering between the drill sleeve 13 and the cap portion 12, which could lead to premature wear of the drill sleeve 13 and the cap portion 12.

[0107] Figure 10 and Figure 11A separate positioning element 27 for positioning the body 17 is specifically shown. In the embodiment chosen here for illustrating the invention, the separate positioning element 27 for positioning the body 17 is composed of a rectangular assembly having at least one fixing device 28, in this case two fixing devices 28, adapted to connect to the receiving portion 28' of the body 17. Thus, the fixing device 28 of the element 27 can be composed of a convex member interacting with the receiving portion 28' (which is composed of a concave member) to secure the body 17 to the separate positioning element 27. Advantageously, one or more receiving portions 28' are positioned at either of the two ends of the body 17, such that the body 17 can be connected and secured to two separate positioning elements 27 located at the two opposite ends of the body 17.

[0108] The independent positioning element 27 functions as follows: Reference marks 24 are pre-drawn on one or more walls 6, 8, 10a and / or 10b to precisely position the holes to be drilled in said walls 6, 8, 10a and 10b relative to the dimensions of the drilling equipment 30. These reference marks 24 are typically composed of lines drawn on the walls 6, 8, 10a and 10b, extending horizontally and vertically along the axes L, T, V of the tank 1. The independent positioning element 27 is arranged at the intersection of the horizontally and vertically extending lines, and is centered by a notch, dash, or similar element 31 located at the center of the element 27. The positioned independent positioning element 27 is thus secured to the wall 6, 8, 10a or 10b by a suction cup 29, which is connected or fixed to said element 27. The suction cup 29 constitutes one embodiment of a device for securing the independent positioning element 27 to the walls 6, 8, 10a, 10b, but of course any other system can be envisioned. In this case, the suction cup 29 advantageously operates in the same manner as the suction cup 19, such that all securing devices can operate by utilizing the Venturi effect through connection to a single compressed gas circuit.

[0109] Once component 27 has been positioned and secured to walls 6, 8, 10a or 10b, body 17 is arranged onto the component (see [link]). Figure 9 Then it was fixed (see Figure 10 This is such that one or more holes in one or more drill casings 13 are exactly opposite to holes to be drilled in walls 6, 8, 10a or 10b.

[0110] The drilling apparatus 30 according to the invention mainly includes the basic components and elements defined in independent claim 1, and advantageously includes one or more additional components or elements defined in the dependent claims.

[0111] Although the invention has been described with reference to several specific embodiments, it is apparent that the invention is by no means limited thereto, and the invention includes all technical equivalents of the described apparatus and combinations thereof if all technical equivalents of the described apparatus and combinations thereof are within the scope of the invention.

[0112] The use of the verbs “comprising” or “including” and their variations does not exclude the presence of other elements or steps besides those recited in the claims. Any reference numerals in parentheses within the claims should not be construed as limiting the claims.

Claims

1. A drilling apparatus (30) for drilling holes in a wall, the drilling apparatus comprising a body (17) housing at least one drill bit (11) made of metal or a metal alloy, the drill bit having at one end a drill head (11') capable of drilling holes in a wall (6, 8, 10a, 10b), the drilling apparatus (30) having a power supply and / or adapted to be connected to an electrical supply. Its features are, The drilling equipment (30) also includes: - A cylindrical cover portion (12) fixed around the longitudinal portion of the drill bit (11), the cylindrical cover portion having a diameter (D); - Drill casing (13), when drilling holes in the walls (6, 8, 10a, 10b), the cover sleeve (12) slides at least along its length (L). The drill casing (13) and the cap sleeve (12) are installed with a sliding fit H7g6 as defined in standard ISO 8015, and The coefficient of friction between the drill sleeve (13) and the cap sleeve (12) is at most 0.2 according to standard ASTM G77.

2. The drilling equipment according to claim 1, wherein, The guide distance L of the cover sleeve (12) being guided in the drill sleeve (13) is at least equal to 2.5 times the diameter of the cover sleeve (12), in other words, L≥2.5D.

3. The drilling equipment according to claim 1 or 2, wherein, The cover section (12) is made of metal or metal alloy.

4. The drilling equipment according to claim 1 or 2, wherein, The main body (17) accommodates multiple drill casings (13).

5. The drilling equipment according to claim 1 or 2, wherein, The drill casing (13) is advantageously mounted on the body (17) in pairs via an insertion part (16).

6. The drilling equipment according to claim 1 or 2, wherein, The drilling equipment (30) includes a dust extraction system for extracting dust generated during drilling.

7. The drilling equipment according to claim 6, wherein, The dust extraction system includes: a chamber (25) fixed to the drill sleeve (13); and a pipe (26) leading to the chamber (25) for extracting and discharging the dust.

8. The drilling equipment according to claim 1 or 2, wherein, The main body (17) includes means for fixing to the wall (6, 8, 10a, 10b).

9. The drilling equipment according to claim 8, wherein, The device for fixing to the wall (6, 8, 10a, 10b) consists of at least one suction cup-shaped part (19).

10. The drilling equipment according to claim 1 or 2, wherein, The cover sleeve (12) includes a stop flange (14) at the end of the cover sleeve opposite to the drill bit (11'), the stop flange restricting the movement of the cover sleeve (12) in the drill sleeve (13).

11. The drilling equipment according to claim 1 or 2, wherein, The drill casing (13) is removably and movably mounted in the body (17) to adjust the distance from the casing to the walls (6, 8, 10a, 10b).

12. The drilling equipment according to claim 8, wherein, The drilling equipment (30) also includes an independent positioning element (27) for positioning the body (17) on the walls (6, 8, 10a, 10b) for drilling.

13. The drilling equipment according to claim 12, wherein, The independent positioning element (27) for positioning the body (17) includes means for fixing to the wall (6, 8, 10a, 10b).

14. The drilling equipment according to claim 4, wherein, The main body accommodates at least six drill casings (13).

15. The drilling equipment according to claim 9, wherein, The device for fixing to the wall (6, 8, 10a, 10b) consists of a plurality of suction cups (19) that operate by suction of the Venturi effect type.

16. The drilling equipment according to claim 11, wherein, The drilling equipment includes at least one clamping collar (22) for the drill casing (13), the clamping collar being used to hold the drill casing (13) in place at a desired distance from the wall (6, 8, 10a, 10b).

17. A system for drilling holes in the walls of a liquid storage tank made of concrete or the like, said system comprising: - A storage tank (1) for storing liquid, the tank (1) comprising at least one wall (6, 8, 10a, 10b) made of concrete or the like; and - Drilling apparatus (30) according to any one of claims 1 to 16.

18. The system according to claim 17, wherein, The storage tank is of type GBS or GST.

19. Use of the drilling apparatus (30) according to any one of claims 1 to 16, the drilling apparatus being used to drill holes in the walls (6, 8, 10a, 10b) of the liquid storage tank (1) made of concrete or the like.

20. The use of the drilling equipment (30) according to claim 19, wherein, The liquid storage tank is a GBS or GST type storage tank (1).

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