CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims the priority of United States Provisional Patent Application No. 62/855,370, filed on May 31 , 2019 and incorporated herein by reference.

TECHNICAL FIELD

[0002] The application relates to a torch cutting system and method for cutting metals.

BACKGROUND

[0003] Oxy-fuel gas cutting torches are commonly used for cutting ferrous alloys and some non-ferrous metals, as cuts can be effected through very thick billets, slabs, blooms or bars, among other items. In operation, an oxy-fuel torch directs an ignited stream of oxygen and fuel gas onto the surface of the metal to be cut. The metal is thus heated to its ignition temperature, at which point a stream of cutting oxygen directed at the surface oxidizes the heated metal to effect the cut.

[0004] In known implementations of typical oxy-fuel torch cutting technologies such as that illustrated by Fig. 1 of the Prior Art, a cutting torch 1 is arranged to project a flow A1 of fuel gas and oxygen, or in some cases just fuel gas, away therefrom along a generally rectilinear path A1. This is normally called a preheating flame. Once the material surface B1 is hot enough, cutting oxygen (e.g., 99+% pure oxygen) A2 is activated, and it will start cutting the molten material away. The cutting torch 1 is conventionally oriented such that its rectilinear path A1 is oriented generally normally to a top surface B1 of an item B to be cut. The cutting stream A2 initiates a cut C in the item B upon some of its material becoming molten by the cutting oxygen A2 which may be assisted by drawing some of the A1 preheating gases into the stream. The flow A2 to extend from the top surface B1 to outward a bottom surface B2. Upon the cut C being initiated, the cutting torch 1 may be displaced in a cutting direction D, here oriented normal to the page of Fig. 1. Whether the cutting torch 1 is being displaced or not, the cutting oxygen stream A2 expands radially from the rectilinear path A2 and exhibits turbulence as it exits the cut C away from the bottom surface B2. Such turbulence in the flow A2, oft referred to as eddy currents (or eddies) E, typically occurs on either sides of the cut C and consists in some of the flow A2 swirling back toward the item B. The larger the tip of the cutting torch 1 , the larger and more powerful may the eddies E be. Hence, when cutting metallic items, such eddy currents E may carry molten material (or slag) being ejected from the cut C onto the bottom surface B2, thus causing a significant amount of unwanted material (also known as deposits, dross, beard, slag, kerf etc.) to remain attached to the item B alongside either edges of the cut C.

SUMMARY

[0005] In accordance with an aspect of the present disclosure, there is provided a torch cutting system comprising: a cutting torch with a cutting tip at an end of the cutting torch, a torch support for supporting the cutting torch such that an angle of a central axis of the cutting tip is at a range of 120 degrees to 150 degrees from a cutting direction, and an actuation system configured to cause a relative displacement in the cutting direction of the cutting torch relative to an object.

[0006] Further in accordance with the aspect, the actuation system is an actuator unit in the torch support and operable to move the cutting torch such that the central axis is oriented at said angle.

[0007] Still further in accordance with the aspect, the torch support is arranged to define a reference plane in which lays the cutting direction, the actuator unit being operable to move the cutting torch parallel to the reference plane and/or transversely to the reference plane.

[0008] Still further in accordance with the aspect, the actuator unit is operable to move the cutting torch such that the cutting path is oriented at an angle relative to a beveling direction laying in the reference plane and intersecting the cutting direction. [0009] Still further in accordance with the aspect, the cutting torch is translationally connected to the torch support, the actuator unit configured for translating the cutting torch along a first, a second and/or a third axes orthogonal to one another, the first axis parallel to the cutting direction.

[0010] Still further in accordance with the aspect, the cutting torch is pivotably connected to the torch support, the actuator unit configured for pivoting the cutting torch about an axis transverse to the cutting direction.

[0011] Still further in accordance with the aspect, the actuation system includes a conveyor arranged for displacing the object.

[0012] Still further in accordance with the aspect, the torch support holds the cutting torch in a given orientation such that the cutting direction is parallel to a surface of the object to cut.

[0013] In accordance with another aspect, there is provided a method of effecting a torch cutting operation comprising: orienting a cutting torch such that a central axis thereof is at an angle ranging from 120 degrees to 150 degrees from a cutting direction; and causing a relative movement between the cutting torch and an object to be cut along the cutting direction, concurrently outletting gas from the cutting torch along a path aligned with the central axis to cut the object.

[0014] Further in accordance with the aspect, causing the relative movement includes moving the object.

[0015] Still further in accordance with the aspect, causing the relative movement includes moving the cutting torch.

DESCRIPTION OF THE DRAWINGS

[0016] Reference is now made to the accompanying figures in which: [0017] Fig. 1 is a schematic view of a typical cutting torch in accordance with the prior art;

[0018] Fig. 2 is a schematic view of a cutting torch configuration in accordance with the present disclosure;

[0019] Fig. 3 is a schematic of an exemplary torch cutting system in accordance with an embodiment of the present disclosure;

[0020] Fig. 4 is a schematic of another exemplary torch cutting system in accordance with an embodiment of the present disclosure;

[0021] Fig. 5 is a schematic of yet another exemplary torch cutting system in accordance with an embodiment of the present disclosure, and

[0022] Fig. 6 is a representation of a reference coordinate system of torch cutting systems in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

[0023] Referring to the drawings and more particularly to Fig. 2, a cutting torch configuration in accordance with the present disclosure is shown, as part of a torch cutting system 10 defining a cutting path A, and an item B in which a cut C is to be effected along a cutting direction D. The torch cutting system 10 and the item B are arranged with respect to one another such that the cutting path A is oriented toward the item B and angled away from the cutting direction D. The cutting torch configuration is shown with respect to a reference coordinate system C,U,Z, with axis X extending parallel to the cutting direction D, axis Z being normal to the page of Fig. 2, and axis Y being orthogonal to axes X and Z, with axes X,Y laying in a plane of the page of Fig. 2. In the forthcoming description, the reference coordinate system C,U,Z and its axes should be understood as geometrical properties of the torch cutting system 10 inherited from its structural arrangement and, unless specified otherwise, not from the item B nor from any notional horizontal ground surface. [0024] The cutting torch configuration shows parts of an exemplary cutting torch 20, the latter being shown in greater detail in Figs. 3-5 and described in exemplary embodiments below. The cutting torch 20 generally includes an elongated tubular member 21 and a cutting tip 22 (or nozzle) disposed at a distal end of the tubular member 21. The tubular member 21 may have a plurality of conduits (not shown) extending along its length, with at least two conduits being fluidly connected to the cutting tip 22 for respectively providing fuel and oxygen flows thereto. The fuel flow (or preheat flow) may include at least one of acetylene, propane, natural gas oxyhydrogen and other fuel gas, alone or in combination with oxygen or air. The oxygen flow, on the other hand, may consist of generally pure oxygen and be referred to as cutting oxygen, whereas oxygen used in the fuel flow may be referred to as preheat oxygen. Inlet and outlet cooling conduits may be provided among the plurality of conduits of the tubular member 21 for cooling the cutting torch 20, for example by providing a flow of coolant, such as water, to and from the cutting tip 22.

[0025] Schematically shown in Fig. 2, the torch support 30 may be generally described as a means for supporting the cutting torch 20 in one or more positions and orientations relative thereto and defined with respect to the reference coordinate system C,U,Z. Indeed, the torch support 30 and the cutting torch 20 are arranged with respect to one another so that the cutting tip 22 may be oriented orthogonally or transversely to the Z axis and/or its cutting path A may be orthogonal or transverse to the Z axis. The cutting torch 20 generally lays in a plane coplanar to the X,Y plane, although the tubular member 21 may veer toward or away from the X,Y plane as it extends to the cutting tip 22.

[0026] In embodiments, the structure of the torch cutting system 10 determines the cutting direction D, which may correspond to a vector parallel to the X axis and offset away from the cutting tip 22 along the Y axis. The cutting path A may be oriented at a forward-facing angle a relative to the Y axis, an orientation which may otherwise be defined by a rearward-facing angle Q relative to the X axis and complementary to the angle a. The rearward-facing angle Q may be in a range of between about 30 degrees and 60 degrees. The rearward-facing angle Q may be defined as an angle between the central axis of the cutting tip 22, equivalent to the cutting path A, and a direction opposite the cutting direction D. It may also be said that the cutting path A is at an angle of (180 degrees - Q) relative to the cutting direction D, and hence the angle between the cutting direction D and the central axis of the cutting tip 22 and/or cutting path A is between 120 degrees and 150 degrees.

[0027] In order to be cut, the item B may be positioned and oriented relative to the torch cutting system 10 such that the cutting path A intersects its top and bottom surfaces B1 , B2 with at least one of the top and bottom surfaces B1 , B2 being generally oriented at the angle Q, at least locally proximate their respective intersection with the cutting path A. Indeed, either one of the top and bottom surfaces B1 , B2 of the item B may be non-planar or otherwise irregular in shape. For example, the item B may be a thick-walled pipe whose outer and inner circumferential walls would respectively correspond to the top and bottom surfaces B1 , B2. In such cases, the item B would be positioned such that a notional plane tangent to the intersection of the cutting path A and least one of the top and bottom surfaces B1 , B2 is generally parallel to the X,Z plane and hence at the angle Q. In Fig. 2, the item B is a plate having a rectangular cross-section, with both surfaces B1 , B2 generally parallel to the X,Z plane. The top surface B1 is positioned at a desired offset from the cutting tip 22, in this case of about 15 cm. In other implementations, the offset may be in a range of between about 0.65 cm and 17.5 cm, depending on characteristics of the item B and/or operational conditions of the torch cutting system 10. The offset may be defined as the distance between the top surface B1 and the cutting tip 22 along the cutting path A, which is a collinear with the central axis of the cutting tip 22. Consequently, it may not be the shortest distance between the cutting tip 22 and the top surface B1. By way of the aforementioned arrangement, any eddy current E induced during the operation of the torch cutting system 10 is generally minimized, and may under certain circumstances be found solely forward of the cutting path A along the cutting direction D. The flow A1 emerging from the bottom surface B2 at a forward-facing angle Q’ corresponding to the angle Q confines the eddy current E to a narrow space between the cutting path A and the bottom surface B2. Conversely, the flow A1 may be said to emerge from the bottom surface at a rear-facing angle adjacent to the forward-facing angle Q’, at which any turbulence in the flow A1 rearward of the cutting path A is negligible or absent. As a consequence, deposits resulting from the cutting operation are reduced on the bottom surface B2. Stated otherwise, orienting the cutting path A by angling the cutting tip 22 away from the direction of cut D toward the angle e may cause a change in the flow dynamics of the cutting process and metallurgy of the item B adjacent the resulting cut C. At angle e the only significant eddy E may occur forwardly of the cutting path A. Any rear eddy current may be negligible.

[0028] In embodiments, the torch support 30 may comprise a support frame (not shown) attachable to a reference structure, for example a floor, a wall or even a vehicle, to orient the torch cutting system 10 such that the X,Z plane is generally parallel to a horizontal ground surface (i.e., a surface normal to gravity). In other embodiments, the torch support 30 may comprise a handle or other like apparatus rendering the torch cutting system 10 operable manually. In some such embodiments, the torch cutting system 10 comprises a guiding system indicative of an orientation of the cutting path A relative to the horizontal ground surface and/or to the item B to be cut. Such guiding systems may include a sensor (e.g., level, accelerometer, gyroscope) configured to detect the orientation and a user interface configured to be indicative of the orientation.

[0029] The item B to be cut may be constructed of various materials such as metals or ferrous or non-ferrous alloys, and may be of various shapes such as beams, billets, tubes, blooms, slabs, plates, ingots, etc. For instance, the cross-sectional dimensions of such beams or billets may be as 20’ wide, 24” thick and 60’ long, though it may be used on substantially smaller items, including ¼” thick sheets. The torch cutting system 10 can slit metal on the full length of the material. The item B may be elongated, including being substantially longer than the cross-sectional dimensions.

[0030] Referring to Figs. 3 to 5, additional components of various embodiments of the torch cutting system 10 are shown. The cutting torch 20 produces the cutting output. The torch support 30 is arranged with one or more actuators 31 , 32, 33 (i.e., an actuation unit 30a) that are operable to position and/or orient the cutting torch 20 relative to the reference coordinate system C,U,Z. By way of this arrangement, the cutting torch 20 may be displaced along the cutting direction D, or be positioned and/oriented relative to the item B. In an embodiment, the cutting torch 20 is movable by the actuation unit 30a along the X,Y plane. A conveyor unit 40 may be present to displace the item B relative to the torch support 30 and/or the cutting torch 20. For example, the conveyor unit 40 may be arranged to displace the item B along one or more directions with respect to the reference coordinate system C,U,Z, for example in a direction opposite the cutting direction D, or in a direction along the Z axis. The conveyor unit 40 may displace the item B intermittently with the cutting operations, for instance to position the item B proximate the cutting torch 20 for a cut, and/or to displace a severed part of the item B away from the cutting torch 20. The conveyor unit 40 is optional.

[0031] Referring to Fig. 3, further characteristics of one such arrangement will now be described. As indicated hereinabove, the cutting torch 20 may incorporate various conduits (e.g., supply conduits, mixing conduits, cooling conduits, casings, etc.) in its tubular member 21 to feed the gas(es) and/or fluids to its cutting tip 22. In Fig. 3, the tubular member 21 may be defined by three portions (or segments), if not more. For example, the tubular member 21 has a proximal portion 21A, an intermediate portion 21 B and a distal portion 21 C. The proximal portion 21 A is connected to supply lines 23. The distal portion 21C supports the cutting tip 22, for example in a position spaced away from the proximal portion 21 A. The intermediate portion 21 B interfaces the proximal portion 21 A to the distal portion 21 C. In Fig. 3, the intermediate portion 21 B offsets rearwardly the distal portion 21 C and cutting tip 22 from an extension of the proximal portion 21A. The proximal portion 21A may be generally upright, whereas the intermediate portion 21 B is transverse (e.g., perpendicular) to the proximal portion 21 A. The distal portion 21 C may project downwardly and at an angle relative to the intermediate portion 21 B, for the distal portion 21 C to be angled by e. In an embodiment, curved segments may be at the junction between portions 21 A, 21 B and/or 21 C, though elbows and bent arrangements are contemplated as well.

[0032] Figs. 4 and 5 show a different arrangement, in which there is no intermediate portion 21 B, with the distal portion 21C connected directly to the proximal portion 21 A. In Figs. 4 and 5, the distal portion 21 C projects downwardly and forwardly from the proximal portion 21A, with the distal portion 21C angled by e. Other arrangements are also contemplated.

[0033] The cutting tip 22 is schematically shown in Figs. 2 to 5. The cutting tip 22 may be any appropriate oxy-fuel gas tip or nozzle, such as post-mix (postmix) cutting tips, pre-mix (premix) cutting tip, cutting nozzles, oxy/fuel cutting tips. As an example, the cutting torch 21 and cutting tip 22 may be as described in a postmixed (a.k.a., post- mixed) oxy-fuel gas cutting torch and nozzle, for instance as described in U.S. Patent No. 6,277,323, incorporated herein by reference. The cutting torch 20 may be a torch and nozzle assembly for postmixed oxy-fuel cutting using an annular stream (or flow) of preheat oxygen surrounding a fuel gas stream. The cutting tip 22 may be secured to the head of the cutting torch 21 by a hollow retaining nut which forms an annular gap with the nozzle assembly for discharging the outer preheat oxygen gas stream. The preheat oxygen gas is connected to a pure oxygen source (e.g., 95%+ purity, ideally 99%+ plurality), and therefore discharges a sizable volume of pure oxygen during operation, to ensure a high flame temperature. Other exemplary cutting torch 20 and cutting tip 22 may be as described in U.S. Patent Application No. 15/429,882, incorporated herein by reference.

[0034] The supply lines 23 may consequently feed appropriate gases and fuel to the cutting torch 20, i.e. , to the cutting tip 22 via the tubular member 21. The supply lines

23 may be flexible lines, such as hoses, to enable movement of the cutting torch 20, as described below. The supply lines 23 may also be connected to an air jet nozzle 24. The air jet nozzle 24 may be positioned forwardly of the cutting tip 22. The air jet nozzle

24 may be operated to remove excess molten metal resulting from the cutting operation. In an embodiment, the torch cutting system 10 is without the air jet nozzle 24. In an embodiment, a mechanical knuckle holding the cutting tip 22 could be provided and move same into a perpendicular orientation to finish the cut. This may eliminate the need for the air jet nozzle 24. [0035] The actuation unit 30a may take various forms, some of which will become apparent in light of the forthcoming description of the embodiments of the torch cutting system 10 shown in Figs. 3 to 5. Such actuation units 30a are arranged to controllably position the cutting torch 20 relative to one or more spatial references. In some embodiments, the actuation unit 30a may be operated to move the cutting torch 20 along a plane parallel to the X,Y plane, for example a plane in which lay the cutting path A and the cutting direction D. It is however contemplated to provide additional degrees of freedom to the cutting torch 20 via the actuation unit 30a, allowing for example to displace the cutting torch 20 in a direction having a component aligned with the axis Z, or even orthogonal to the X,Y plane. The X and Z axes may be said to form a reference plane R (Fig. 6), relative to which the actuation unit 30a may be arranged to position and orient the cutting torch 20. For example, the cutting torch 20 and its cutting path A may be angled relative to the angle e (e.g., by an angle b) and to the cutting direction D so as to be oriented along a beveling direction F, in which a bevel may be imparted to the cut item B.

[0036] In Fig. 3, the actuation unit 30a has a rotational actuator 31 with a rotational output operatively connected to the cutting torch 20. The rotational actuator 31 may include a bidirectional motor providing a reciprocating motion to an arm 32, e.g., such as a pendulum movement. The motor of the rotational actuator 31 may also be a unidirectional motor using gravity or biasing means to cause the pendulum movement. Reduction components (e.g., gear box) or transmission components (belt and pulley, clutch) may be used as well to control the velocity of movement of the cutting torch 20. When the arm 32 is aligned with gravity, the cutting tip 22 and cutting path A are at angle e. The rotational actuator 31 depicted herein is arranged such that the cutting torch 20 is pivotable about an axis parallel to the Z axis. However, the actuation unit 30a may also include one or more additional rotational actuators via which the cutting torch 20 may be rotated about other axes, for example about axes parallel to the X axis or even to the Y axis. Such arrangements may for example allow to impart a bevel to cuts effected by the torch cutting system 10. [0037] In Fig. 4, the actuation unit 30a has a first linear actuator 33. The first linear actuator 33 may be oriented to displace the cutting torch 20 between positions in general alignment with the X axis. For instance, a direction of the first linear actuator 33 may be parallel to the cutting direction D, although paths diverging or converging relative thereto by certain angulations may be considered. Hence, the first linear actuator 33 may be generally horizontal. The first linear actuator 33 may be any appropriate type of linear actuator, such as a cylinder, ballscrew, or rack and pinion system, among others, and be powered by any suitable means (e.g., pneumatic, hydraulic, electrical, etc.).

[0038] Fig. 5 shows the first linear actuator 33 in conjunction with an additional second linear actuator 34. The second linear actuator 34 may be connected serially to the first linear actuator 33 and cooperable therewith for the cutting torch unit 20 to be displaceable in the X,Y plane. For example, the second linear actuator 34 may have a range of motion aligned with the Y axis, be upright (e.g., vertical). In an embodiment, the cutting torch 20 has the path A aligned with a bottom from edge of the item B (i.e. , a home or initial position), as in Fig. 5, to be moved upwardly by actuation of the second linear actuator 34, and then, sequentially, in the cutting direction X1 by the first linear actuator 33. The second linear actuator 34 may be any appropriate type of linear actuator, such as a cylinder, ballscrew, or rack and pinion system, among others, and be powered by any suitable means (e.g., pneumatic, hydraulic, electrical, etc.).

[0039] The actuation unit 30a consequently has a holder 35 to connect the cutting torch 20 (e.g., via a back piece of its tubular member 21), to other parts of the actuation unit 30a, such as to the arm 32, or to a carriage of the first linear actuator 33 or second linear actuator 34 (e.g., including a connection to a piston thereof). The holder 35 may be connected to the first linear actuator 33 or second linear actuator 34. The holder 35 may be a clamp, fastener(s), collar and/or embedded support. In embodiments such as the one depicted in Fig. 5, the holder 35 may be said to form a back piece of the cutting torch 20. [0040] The conveyor unit 40, shown in Fig. 3, may also be present in the embodiments of Figs. 4 and 5. The conveyor unit 40 may have one or more rollers 41 , such as those of a conveyor. The conveyor unit 40 may be automated, or may facilitate a manual displacement of item B. The rollers 41 may also include a belt, for example with an encoding system to precisely control the movement of the item B in a direction aligned with axis Z. Other types of conveyor unit may be used. Although not shown, the conveyor unit 40 or a separate system (e.g., a manually operated system) may feature clamps to fix the item B so as to hold it in position during the cutting operation.

[0041] In an embodiment a controller may be programmed to automatically or semi- automatically operate the torch cutting system 10 and functionality of its components, such as the cutting torch 20, the actuation unit 30a and the conveyor unit 40, if present. The controller may be communicatively coupled to a non-transitory computer-readable memory unit, that include computer-readable program instructions executable by the controller for operating a cutting operation of the torch cutting system 10. For example, the controller may open and close the cutting torch 20 such as via valves (e.g., electronic, solenoids) to supply gas(es) and fuel to the tubular member 21 and cutting tip 22, may operate the actuation unit 30a to move the cutting torch 20 at a desired velocity, and/or may sequentially operate the conveyor unit 40, if present, after or before the cutting of a part of the item B. The controller may be provided with appropriate sensors, such as optical sensors, accelerometers, encoders, thermocouples, manometers, pressure sensors, etc., whether integral to the torch cutting system 10 or external thereto, to ensure operation is as instructed. The operational parameters may be determined as a function of properties of the item B, for example the material(s) it is made of (e.g., composition, grade, density, etc.) its mechanical properties, its dimensions and its shape, among other possibilities.

[0042] The torch cutting system 10 may be part of strand casting machines, such as those found in steel mills. If there is more than one machine, they are typically spaced apart by a distance depending on the size of material they are casting, for example by 4 to 6 feet, center to center. The torch cutting system 10 of Figs. 3,4 and 5 may be used with standard casting equipment on the market, and may go up to 12’ wide. The embodiment of Fig. 4 may be particularly useful for wide slabs. The torch cutting system 10 may be used to cut offline, as part of offline cutting machines, CNC cutting machines, crawler and track system etc. Material can be cut hot or cold, it can be cut while casting or in another section waiting to be slit (slice if sections). Slitting may usually be done offline.

[0043] In an embodiment, the torch cutting system 10 may be configured to replicate the concept of an air knife, i.e. , a tool used to blow off liquid or debris from products as they travel on conveyors. Air knives may for example be used in manufacturing or in a recursive recycling process to separate lighter or smaller particles from other components for use in later or subsequent steps, post manufacturing parts drying and conveyor cleaning, part of component cleaning. The knife consists of a high-intensity, uniform sheet of laminar airflow sometimes known as streamline flow. In some embodiments, an industrial air knife is a pressurized air plenum containing a series of holes or continuous slots through which pressurized air exits in a laminar flow pattern. The exit air velocity then creates an impact air velocity onto the surface of the object the air is directed onto. This impact air velocity can be up to several tens of thousands ft/min (e.g., 40,000 ft/min) to alter the surface of a product without mechanical contact.” By angling the cutting torch 21 in the angled orientation e as described above, to orientation the oxygen path, no significant eddy currents are formed on the sides of a cut (i.e., in direction Z). A eddy current C as in Fig. 2 may form at the front of the cut in the cutting direction X1. The slag is pushed forward until it reaches the side of the metal leaving little or no slag underneath. Any slag left may be removed for instance by air jet nozzle 24 if present.

[0044] In an embodiment, the torch cutting system 10 may be used in a method of effecting a torch cutting operation comprising: orienting a cutting torch such that a central axis thereof is at an angle ranging from 120 degrees to 150 degrees from a cutting direction; and causing a relative movement between the cutting torch and an object to be cut along the cutting direction, while concurrently outletting gas (e.g., the oxygen stream) from the cutting torch along a path aligned with the central axis to cut the object. The relative movement includes moving the object and/or moving the cutting torch.

[0045] The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.