METHOD AND APPARATUS FOR REMOTE UNDER WATER TORCH CUTTING

Abstract: A method for torch cutting metal walls by burning powdered metals admixed with a gas oxidizer to establish a pre heat flame at a cutting zone and followed by continuously adding a gas cutting agent for intensifying said flame and cut through the metal wall by burning and melting, and an apparatus to implement this method and which locates a body to the wall to be cut and carries and advances a torch over said wall with the discharge of said powdered metals and gases for pre heat and followed by the continuous addition of said cutting agent for continuous cutting of the wall, and all of which is adapted to remove under water operation within steel casings and over steel plate, as well as through other metals and materials.

Description: This invention relates to under water cutting of steel walls or plates, and preferably the cutting of steel pilings. Heretofore, the methods for cutting steel underwater have been difficult to employ and the results thereof restricted. Oxy-hydrogen torches for this purpose have been provided for the introduction of compressed air into a surrounding sleeve in order to prevent the intrusion of water that would otherwise extinguish the flame; however cutting efficiently with that method is limited due to the excessive pre heat time required, and only thin cuts can be made therewith, and without cutting through mud, scale, cement or rock etc.. Another cutting method involves striking an electric arc in the presence of oxygen introduced through the cutting rod, which works well with steel but not with non ferrous materials and other compositions such as concrete, rock, coral, etc.. Also, a good electric ground is often very difficult to attain. An electrical development is the use of aluminum and/or magnesium rods within steel tube, used in steel cutting processes, with oxygen applied therethrough for oxidization. In the case of non-ferrous materials, the intense heat of burning crumbles the materials and the oxygen stream blows it away. Another development is the use of metal powders for intensifying heat and corrosive action. For example, mixtures of magnesium and iron dust support combustion in the presence of pure oxygen, but again with the use of a rod striking and electric arc. Such metal rods are self consuming in short lengths of time, which greatly shortens the cutting time. Furthermore, the use of electric arc cutting involves excessive down time because of the necessity to replace said rods so frequently; since such rods consume in 30 to 60 seconds. Therefore, it is a general object of this invention to provide a continuously operable method of cutting steel casings or plate under water with a gas torch using powdered metal mixtures, without resort to electric arc rods that have been relied upon in the past. Heretofore, it has been found to be difficult to attain sufficiently high pre heat temperatures under water, prior to discharge of the cutting agent such as pure oxygen, In order to perform cutting of steel plate such as that of casings. However, there are the aforesaid powdered metal mixtures that will raise the temperature of a flame considerably, but which are used sparingly because of their cost. Support for combustion of these powdered metals is the use of an oxidizer and as a cutting agent. It is therefore an object of this invention to substantially raise pre heat temperature in a cutting torch by providing the combustion of powdered metals, for example to raise the cutting zone temperature in excess of 2204°C (4000°F) and under which condition a cutting agent is discharged therewith for cutting the steel casing or plate. With the exothermic condition thus provided, this torch will now melt through mud, clay, corrosion scale and marine growths, while efficiently cutting steel and other metals on a continuing basis. French Patent Specification 837 791 relates to a cutting torch which is intended for use in heavy cutting but this torch is not suitable for use under water. The extreme heat generated for scarfing and cutting is achieved by using a combustible wire feed outside a burner nozzle and thus it is post mixed at the combustion point. Because the wire has to be fed from some proximate source the burner is obviously incapable of underwater use. United States Patent Specification 2 975 002 refers to burning metal powders to produce high cutting flame temperatures but it does not suggest or disclose that such metal powders could be used in a pre-heat flame. United States Patent Specification 2 664 668 shows an external powder feed scarfing process and apparatus. Such a system cannot be used underwater due to the wetting of the powder making it unable to ignite. According to the present invention therefore a method for cutting through metal walls and the like under water, and including: a first step of pre-heating a cutting zone on the wall with a pre-heat flame at a caloric output to attain a pre-heat temperature in said cutting zone, and a second step of adding a calorie increasing cutting agent into the pre-heat flame to increase the caloric output of the pre-heat flame, pre-heating the cutting zone on the wall with a pre-heat flame comprising metal dust in a carrier of oxidising gas, and by causing the calorie increasing cutting agent to burn the metal dust at increased temperature together with the metal wall of the cutting zone and burning therethrough. According to another aspect of the invention apparatus for carrying out the method set forth above includes a nozzle having at least two fluid connections thereto, the nozzle has a first connection for a metal powder admixed with a gas oxidiser and a second connection for a gas cutting agent, and having a jet passage for each of said connections and opening at a front discharge end of the nozzle, a means (A) locating the discharge end of the nozzle in spaced relation to the metal wall to be cut, a means supplying the metal powder and gas oxidiser mixture to the first connection to discharge from said jet passage therefor and for ignition to establish a high temperature pre-heat flame at a cutting zone of the metal wall, and a means supplying the gas cutting agent to the second connection to discharge from said jet passage therefor to intensify the aforesaid pre-heat flame and thereby cut through the metal wall by burning and melting. In order to monitor and/or observe the progress of the cutting operation temperature probes and light probes can be provided. For example, thermocouples to sense the pre-heat temperature, and fiber optics to sense the light intensity for visual observation. Also, closed circuit television can be employed. It is necessary that a cutting torch operate efficiently in the under water cutting of steel casing and the like, and that its operation is not impeded by obstructions such as mud, scale, cement or rock, etc. It is necessary that pre-heat of sufficient temperature attained in a short length of time. And, it is necessary that the cutting operation be monitored, so that cutting is implemented only when the required pre-heat is attained. The under water cutting torch disclosed herein provides these necessities and is adaptable to many under water situations. A pilot flame is shielded from the intrusion of the surrounding waters, and/or a spark igniter is provided. Pre-heat is attained at high temperature by providing a powdered metal-gas supply. And, the cutting is achieved by discharging pure oxygen, hydrogen fluoride or similar agent, when pre-heat temperature is reached, and all of which is monitored by temperature probes, light probes, and television cameras. A feature of this invention is the controlled positioning of the torch and its controlled drive for continuous cutting operation. The foregoing and various other objects and features of this invention will be apparent and fully understood from the following detailed description of the typical preferred form and application thereof, throughout which description reference is made to the accompanying drawings, in which : Figure 1 is a vertical sectional view taken through a casing, with the apparatus of the present invention positioned therein and showing the process of cutting through the interior wall thereof; Figure 2 is an enlarged cross-sectional view taken as indicated by line 2-2 on Figure 1 and showing the rotating carriage and torch extension cylinder and piston means therefor; Figure 3 is a view taken as indicated by line 3-3 on Figure 1 and showing the torch mounting and its fluid supply connections; Figure 4 is a longitudinal sectional view of the torch taken as indicated by line 4-4 on Figure 1; Figure 5 is a horizontal sectional view taken as indicated by line 5-5 on Figure 1 and showing the centering means for positioning the apparatus within the casing; and Figure 6 is an enlarged cross-sectional view taken as indicated by line 6-6 on Figure 5 and showing a centering means extension cylinder and piston means and its fluid connections. This invention relates primarily to remote under water torch cutting that is effective in cutting steel and non-ferrous materials including rock, coral etc. The method herein disclosed is adapted to cut steel plates and casings and the like, which may be fouled with marine growth and other materials such as rock. This method employs metal powders such as mixtures of magnesium and iron dust that will increase combustion temperatures in the presence of an oxidiser, in order to attain the required pre-heat temperature and cutting temperature in a short length of time. This method involves, generally, a pre-heat flame supplied with a dust admixture of combustible powdered metal or metals and a gas carrier, discharged and ignited in the presence of a cutting agent causing it to burn with intense heat through walls of material such as steel and the like. More particularly, this method involves the under water torch discharge of a dust admixture of combustible powdered metal and a gas carrier for pre-heating the cutting zone to a temperature in the range of 1927° to 2760°C (3500° to 5000°F) followed by the admixture thereto of a calorie increasing cutting agent such as oxygen gas, so as to burn through the metal walls of material such as steel and the like. In accordance with this invention, the calorie increasing agent can vary, a basic cutting agent being pure oxygen, discharged under pressure into the 1927° to 2760°C (3500° to 5000°F) pre-heat flame, when the cutting zone established thereby has reached the required temperature (by observation or otherwise), and so that the steel or other metals combine with the oxygen cutting agent and cutting through the wall thereof. In practice, the caloric output increases within the pre-heat flame and is increased as the steel or other metal wall oxidises and melts away at temperatures up to and exceeding 2760°C (5000°F). A calorie increasing agent for use with or in lieu of pure oxygen is hydrogen floored, discharged under pressure into the 1927° to 2760°C (3500° to 5000°F) pre-heat flame when the cutting zone established thereby has reached the required temperature (by observation or otherwise), and so that the steel as well as non-ferrous materials are melted through. The hydrogen fluoride is known to chemically attack metals and other materials at extremely high temperature in the range of 1927°C (3500°F) and upward, and thereby cut through steel and other metals as well as rust, scale, rock, concrete, coral and mud etc. In practice, the burning of steel with hydrogen fluoride with oxygen results in ferrous and/or ferric fluoride while dissipating the hydrogen, and thereby instantly melting through the aforesaid steel as well as melting through the other said non-ferrous materials. In carrying out this invention, the metallic dust considered and used is basically of two types, flake dust and atomised dust, the latter configuration as stated, while atomised metallic dust is of minute spherical configuration. In practice, the atomised metallic dust is used in carrying out this method or torch cutting steel plates and the like is of 100 to 325 micron (mesh), which is admixed with a carrier of air or oxygen. In practice and for example, approximately .1223 Kg/minute (0.27 pounds/minute) of metal dust is admixed with 0.114 m³/minute (4.06 cubic feet/minute) of cutting agent gas, thereby establishing a ratio of 1.067 Kgm⁻³ (0.0666 lb ft⁻³) cutting agent gas. This ratio varies dependent upon metal dust density and upon the jet or apertures through which the mixture is ejected. Chipped or flaked metal dust is not as reliable as the atomised spherical form thereof, since the latter does not tend to bridge up, and so does not clog passages and/or small openings and apertures. That is, spherical metal dust is free flowing and is most satisfactory under the conditions that prevail herein. The dust size that has given most satisfactory results is 200 micron (.0029 inch dia.) to 325 micron (.0017 inch dia.). This method may also include a preliminary step of providing a pilot flame of combustible gas and an oxidiser; and alternately a spark applied momentarily for ignition. This inventive method resides in the use of powdered metal dust and a gas carrier that supports its combustion for pre-heating, followed by the introduction of an oxidiser to corrosively intensify the cutting action. In practice, the gas carrier for pre-heat is oxygen, providing a combustible dust mixture that burns at a 1927° to 2760°C (3500° to 5000°F) temperature for rapid pre-heating of the zone to be cut. The method hereinabove described includes a preliminary step of ignition by means of a pilot flame or by a spark generator, and in an under water environment the pilot flame is protected by burning it within a chamber and shielded from the surrounding waters. The first pre-heating step is conducted by burning powdered metal mixed as a dust in a carrier gas that supports combustion at 1927° to 2760°C (3500°F to 5000°F) temperature suitable for pre-heating the cutting zone, using a gas such as air or oxygen. And the second cutting step is conducted by adding an oxidiser for corrosive action, such as pure oxygen and entered into the centre of the prevailing pre-heat flame in order to intensify heating and corrosively burn through the wall to be cut and in the presence of the metal dust mixture that is continuously supplied thereto. The second step is continued until the desired cutting operation is completed and the steel piling or plate is severed. The metal powder and gas carrier is supplied under controlled pressure, and is supplemented by adding the gas oxidiser as a cutting agent which intensifies the existent flame and provides the corrosive action necessary to the rapid and continuous cutting action. The additional oxidizer or cutting agent can be a gas mixture of hydrogen fouride, in lieu of oxygen, used separately or in combination with ogygen, to attain a residue free cutting operation. The completed cut is then slag free with no chance for re-welding of the separated wall of steel, thereby eliminating separation problems. Referring now to the drawings, I have shown an apparatus for remote under water torch cutting of steel casing, using the powdered metal pre heat and intensely corrosive cutting flame method hereinabove described. The casing is shown as a vertically disposed tubular member that is round in cross section, having outer and inner walls 10 and 11. The apparatus herein disclosed is designed to be inserted into and lowered in the casing to be cut circumferentially from the interior thereof, as is clearly shown. Accordingly, the apparatus carries a torch T supplied with powdered metal and gases, and under control of means as will now be described. The supply of combustible materials can be carried on and by the apparatus as by means of pressure bottles and canisters, or preferably remotely from the surface of the waters as shown. The torch cutting apparatus as it is disclosed herein is comprised, generally, of a body B, locating means A for positioning the body, and a carriage and drive means C for advancing the torch T relative to the wall surface to be pre heated and then cut or severed. A feature which facilitates insertion and lowering of the apparatus into the casing is a torch positioning means D which is retractile. Another feature which yields to interfering obstructions such as rust and scale and marine growth is a torch guide means E. This apparatus positions the torch T within the casing at a desired level and then drives the torch around the inner wall 11 thereof and in predetermined spaced relation thereto while supplied with the powdered metal dust and the added oxidizing or cutting agent to effect circumferential cutting of the casing on a continued basis. The apparatus of this invention will be described herein as it is adapted to the remote under water cutting of steel casings. Accordingly, the body B is an elongated vertically disposed member adapted to be inserted into and lowered to a determined depth or level within the casing. As shown, the body B is a slender tube that is subsequently centered coaxially within the inner casing wall 11, by the locating means A next described. In practice, the locating means A is at the lower end portion of body B, in which case the carriage and drive means C for carrying the torch T is carried by the body B with the upper end portion of the body accessible for the attachment of gas and hydraulic and electric lines as may be required. As shown, the body B is a tubular cylinder of relatively small diameter suspended by a cable 12 and having a support for the carriage and drive means C, the support being shown as an upwardly facing shoulder 13. The locating means A as shown in Figs. 1, 5 and 6 positions the body B on the central axis of the casing, and is comprised of spaced retractile members extended into positioned engagement with the inner wall 11 of the casing. As shown, there are upper and lower sets of circumferentially spaced radially extensible members in the form of positionable legs 14 projecting from cylinder and piston means 15. There are at least three cylinder and piston means 15 at both the upper and lower positions, carrying the legs 14 horizontally and radially disposed from the center axis of body B. In practice, the cylinder and piston means 15 and legs 14 combinations are alike, preferably identical, and each involves a cylinder 16 carried by the wall of body B, and a piston 17 reciprocable on an axis radial to the axis of body B. The cylinder and piston means 15 is double acting, with the leg 14 connected to the piston 17 and projecting on said radial axis. As shown, fluid lines 18 communicate with opposite closed and/or sealed ends of the cylinder 16 and enter into the tubular body B so as to extend upwardly therefrom and to and above the water surface (not shown) for the control of operating fluid, preferably hydraulic fluid. The control therefor which is not shown, reversably pressures the lines 18 and simultanesouly positions the cylinder and piston means 15, to either extend or retract the same. A feature of the cylinder and piston means 15 is an adjustable stop therefor, show as a screw 19 entering the cylinder 16 to limit extension of piston 17 and leg 14, and with a lock nut 20. The limited extended positions of the legs 14 is shown in Figs. 1 and 5, whereas the retracted position of the piston 17 and leg 14 is shown in Fig. 6. It will be understood that the retracted legs clear obstacles with the casing wall 11. It is also to be understood that the positioning means A can be carried by the upper end portion of body B, so as to be associated with the upper section of casing being severed and removed. The carriage and drive means C for advancing the torch T is shown in Figs. 1 and 2, for advancing the torch around the inner casing wall 11. The carriage and drive means C is comprised of a collar 21 rotatable on the body B and a motor drive 22 to rotate the collar. Adjacent to and above the shoulder 13 on body B there is a concentric bearing cylinder 23 on which the collar 21 is free to rotate, the collar being a cylindrical member with its lower face slideably supported upon the shoulder 13, and with its upper face captured by a ring 24 secured onto the body. The collar 21 is positioned by the collar and ring to rotate at a determined height on the body B and has a driven gear 25 meshed with a drive gear 26 revolved by a motor M. The motor M is preferably a positive displacement type fluid powered motor for speed control by the rate of fluid flow through lines 27 extending therefrom and to and above the water surface (not shown) for adjustable flow of operating fluid, preferably hydraulic fluid. The control means which is not shown, is any state of the art metering device that controls the rate of flow for precise speed operation of motor M and movement of the carriage collar 21. The collar 21 is drive continuously through one complete revolution when cutting off a section of casing. As shown, the motor M is carried by a bracket 28 at the exterior of body B, with the fluid lines 27 accessible as they extend to and above the water surface. The torch positioning means D is shown in Figs. 1, 2 and 3, and like means A hereinabove described is a retractile means for extending the torch T into working position. The torch positioning means D is comprised of a cylinder and piston means 29 carried by the collar 21 and an adjustment means 30 positioned thereby to carry the torch T. As best illustrated in Fig. 2, the cylinder and piston means 29 is carried by and projects radially from one side of the rotating collar 21 and involves a cylinder 31 and piston 32 reciprocal on a horizontally disposed radial axis from the center of rotation. The cylinder and piston means 29 is double acting, with a mounting bar 33 connected to the piston 32 and projecting on said radial axis. As shown, fluid lines 34 communicate with opposite closed and/or sealed ends of the cylinder 31 and extend upwardly therefrom and to and above the water surface (not shown) for control of operating fluid, preferably hydraulic fluid. The control therefor which is not shown, reversably pressures the cylinder and piston means 29, to either extend or retract the same. A feature of the cylinder and piston means 29 is an adjustable stop therefor, shown as a screw 35 entering the cylinder 31 to limit extension of piston 32 and mounting bar 33, and with a lock nut 36. The limited extended position of the mounting bar 33 is shown in Fig. 1, whereas the retracted position of the piston and bar is shown in Fig. 2. It will be understood that the mounting bar 33 is retracted so as to withdraw the torch T from the inner side wall 11 of the casing to clear obstacles when moving therein. The adjustment means 30 for positioning the torch T carries the base of the torch next described, and swivels the torch so that its angular position with respect to wall 11 of the casing can be set as may be required. As shown, the adjustment means 30 is comprised of a clamp 37 adjustably positioned on the mounting bar 33 to move therewith. Since the mounting bar 33 is essentially a piston rod of round configuration and free to turn, there is a rigid guide rod 38 embraced by a bifurcated portion 39 of clamp 37 to maintain an erect and upright position of said clamp that carries the base of the torch T. The swivel of adjustment means 30 for adjusting the torch is best illustrated in Fig.3 and is comprises of a second clamp 40 disposed on a horizontal transverse axis normal to the axis of the mounting bar 33. The clamp 40 adjustably rotates on a pin in the form of a bolt 41 with a nut 42 which tightens the second clamp onto the first mentioned clamp 37. A typical angle of adjustment when cutting inside vertically disposed casing is approximately 15° as shown in Fig. 1. The torch T which is unique with this invention is provided to handle at least two and preferably four separate fluid supplies, in order to practice the powdered metal pre heat and intensified flamecutting method hereinabove described. Accordingly, there are two basic and preferably four fluid supply lines 51 - 54, all accessably extending to and above the water surface and connected to fluid supplies as will now be described. Line 51 is connected to a pressure and rate of flow regulated supply means of metal dust admixed with a gas carrier of oxidiser as hereinabove described to establish a pre-heat flame at 1927° to 2760°C (3500° to 5000°F). And, line 53 is connected to a pressure and rate of flow regulated supply of the cutting agent such as oxygen, or hydrogen flouride, or a mixture of the two, as hereinabove described to be added to the above mentioned preheat flame so as to intensify the metal-oxidizer flame and thereby establish a corrosive burning and/or melting through of the steel casing, or other metal and materials that may be invovled. The cutting agent is introduced at a fixed point in the center of the preheat flame for an effective cutting effect. The third fluid supply line 52 is provided to supply a combustible compressed gas and oxidizer to a pilot means F. And, the fourth fluid supply line 54 is provided to supply a displacement gas such as compressed air to exclude and/or purge surrounding waters from the aforesaid pilot flame F. The torch T is comprised of a manifold base 55 and a multi jet nozzle 56. The base 55 is secured to the clamp 40 of the torch mounting D and is coupled to the fluid lines 51, 52 and 53, the base having concentric inner and outer forwardly facing channels 61 and 62 in open communicatior with the lines 51 and 52 respectivley, and having a center port 63 in open communication with the line 53. The base 55 and nozzle 56 have interface engagement where the channels 61 and 62 and port 63 open forwardly, there being jet passages 71, 72 and 73 through the nozzle to open at the front discharge end thereof. The supporting pilot flame is established by outer circumferentially spaced series of jet passages 72 in open communication with the outer channel 62. The high temperature preheat flame is established by an inner circumferentially spaced series of jet passages 71 in open communication with the inner channel 61. And, the ultimate cutting flame is established by a central jet passage 73 in open communication with the port 63. The arrangement of manifold channels and jet passages is clearly illustrated in Figs 3 and 4, whereby three distinct flames emanate from the nozzle 56; (1) a pilot flame, (2) a preheat flame, and (3) a cutting flame. In carrying out this invention, the pilot flame (1) is maintained continuously so as to ignite the preheat flame (2) when required, and the preheat flame is then maintained until the cutting zone is conditioned for cutting. The cutting flame (3) is then established by adding the cuting agent so as to made the continuous cut as it is shown started in Fig. 1. The torch guide means E and pilot means F operate together to protect the nozzle 56 by shielding the discharge of gases and admixtures hereinabove described. As shown in Figs. 1 and 4, a retractile shield 75 of means F slides over the nozzle 56 so as to be extended radially by a spring 76, and stopped by a ring 77. A key pin 78 engages a slot 79 in the shield to prevent its rotation, the shield being a forwardly open tube extending from the discharge end of the nozzle 56. In order to prevent encroachment of surrounding waters, the extending portion of shield 75 carries a manifold 80 that is coupled to the said fourth fluid supply line 54 to supply the displacement gas such as air, and thereby purge the flame chamber formed thereby ahead of the nozzle. The guide means E is shown comprised of a follower 82 in the form of a wheel that rides on the inner wall 11 of the casing, so as to pass over any obstructions such as scale and marine growth. The angular position of the follower 82 is adjusted by a clamp 83 having a bolt spaced from and parallel to bolt 41 of adjustment means 30, and set by a nut (not shown). The shield 75 retracts on nozzle 56 when the wheel follower 82 passes over inner diameter obstructions, while maintaining a determined spaced relation to said inner wall 11 and any debris theron. A spark generating means 90 shown in the form of a plug is exposed through the shield and to the flame chamber within the shield and is powered through an electric cable 91 from above the water surface, to ignite the pre heat flame and/or the pilot flame. From the foregoing it will be understood how the torch cutting method of this invention is performed, and particularly the manner in which it is performed remotely and under water. The apparatus disclosed herein is especially adapted to cut from the interior of casing and the like, and is operated entirely remote and above the water surface to supply gas, gas admixture with metal powders, and fluid and electric power sources. A pilot flame and/or spark ignition means is provided for initiating the preheat flame, said preheat flame being a high heat powdered metal and gas flame for rapid conditioning of the cutting zone, and to which the cutting agent is added for cutting. Having described only the typical preferred forms of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art as set forth within the limits of the following claims.

Claims: A method for cutting through metal walls and the like under water, and including: a first step of pre-heating a cutting zone on the wall (10,11) with a pre-heat flame at a caloric output to attain a pre-heat temperature in said cutting zone, and a second step of adding a calorie increasing cutting agent into the pre-heat flame to increase the caloric output of the pre-heat flame characterised by pre-heating the cutting zone on the wall (10,11) with a pre-heat flame comprising metal dust in a carrier of oxidising gas, and by causing the calorie increasing cutting agent to burn the metal dust at increased temperature together with the metal wall (10,11) of the cutting zone and burning therethrough. A method of cutting by burning through metal walls underwater as set forth in claim 1, characterised in that the metal dust includes any one or combination of the metals, magnesium, iron and aluminium, in powdered form carried by said oxidising gas. A method of cutting by burning through metal walls underwater as set forth in claim 1, or claim 2, characterised in that the calorie increasing cutting agent is oxygen, or hydrogen fluoride or a mixture thereof. A method of cutting by burning through metal walls underwater as set forth in claims 1-3, characterised in that the pre-heat flame temperature is in the range of 1927° to 2760°C (3500° to 5000°F). A method of cutting by burning through metal walls underwater as set forth in any one of claims 1-4, characterised in that the second step burning is in excess of 2760°C (5000°F). A method of cutting by burning through metal walls underwater as set forth in any one of claims 1-5, characterised in that the metal dust is powder of flake configuration. A method of cutting by burning through metal walls underwater as set forth in any one of claims 1-5, characterised in that the metal dust is powder of atomised spherical configuration. A method of cutting by burning through metal walls underwater as set forth in any one of claims 1-7, characterised in that the metal dust is of 100 to 300 micron (mesh). Apparatus for carrying out the method set forth in claim 1 including : a nozzle (56) having at least two fluid connections (51)(53) thereto, characterised in that the nozzle (56) has a first connection (51) for a metal powder admixed with a gas oxidiser and a second connection (53) for a gas cutting agent, and having a jet passage (71) (73) for each of said connections and opening at a front discharge end of the nozzle (56), a means (A) locating the discharge end of the nozzle in spaced relation to the metal wall (10) (11) to be cut, a means supplying the metal powder and gas oxidiser mixture to the first connection (51) to discharge from said jet passage (71) therefor and for ignition to establish a high temperature pre-heat flame at a cutting zone of the metal wall (10)(11), and a means supplying the gas cutting agent to the second connection (53) to discharge from said jet passage (73) therefor to intensify the aforesaid pre-heat flame and thereby cut through the metal wall (10)(11) by burning and melting. Apparatus as claimed in claim 9, characterised in that there is a drive means (c) for advancing the nozzle over the metal wall (10)(11). Apparatus as claimed in claim 10, characterised in that said drive means (c) comprises a positive displacement fluid powered motor (m) responsive to a rate of flow metering device for the precise speed advancement of the nozzle (56) over the metal wall (10)(11). Apparatus as claimed in claims 9, 10 and 11, characterised in that the nozzle (56) has a circumferentially spaced series of jet passages (71) for discharge of the metal powder and oxidiser admixture from the first connection (51) thereto, and has a central jet passage (73) for discharge of the gas cutting agent from the second connection thereto (53). Apparatus as claimed in claims 9-12, characterised in that the means (A) locating the discharge end of the nozzle (56) is comprised of retractile members (14)(15) extended into positioned engagement with the metal wall (10)(11) to hold the nozzle (56) in said spaced relation to the metal wall to be cut. Apparatus as claimed in claims 9-13, characterised in that the means supplying the metal powder and gas oxidiser is a pressure and rate of flow means supplying a mixture of metal powder in the range of 100 to 325 micron (mesh) and in a ratio of substantially 1.067 Kgm⁻³ (0.0666 lb ft⁻³) of gas oxidiser. Apparatus as claimed in claims 10-14, characterised in that the means supplying the gas cutting agent is a pressure and rate of flow means. Apparatus as claimed in claims 10-15 and including : a third connection (52) for a combustible gas and oxidiser, and having a jet passage (72) for said connection (52) and opening at the front end of the nozzle, and means for supplying the combustible gas and oxidiser to the third connection (52) to discharge from said jet passage therefor for ignition to establish a pilot flame for ignition of the high temperature pre-heat flame. Apparatus as claimed in claim 16, characterised in that the nozzle (56) has at least two concentric circumferentially spaced series of jet passages (71)(72), one for discharge of the metal powder and oxidiser admixture from the first connection (51) thereto and the other for discharge of the combustible gas and oxidiser from the third connection (52) thereto, and has a central jet passage (73) for discharge of the gas cutting agent from the second connection (53) thereto. Apparatus as claimed in any one of the preceding claims 9-17 for cutting tubular metal casing walls, characterised by a body (B) for insertion into the tubular metal casing (10)(11) and having a central axis, a carriage and drive means (C) for revolvement around the central axis of the body (B) and within the tubular metal casing wall (10)(11), said nozzle (56) being supported by and disposed radially from the central axis of the body (B) and carriage, and means (A) locating the central axis of the body concentric with respect to the centre axis of the tubular metal casing and with the discharge end of the nozzle (56) in spaced relation to an inner diameter wall (11) of the tubular metal casing. Apparatus as claimed in claim 18, characterised by means (12) for suspending the body (B) within the tubular metal casing (10)(11). Apparatus as claimed in claims 18 and 19, characterised in that the carriage is in the form of a collar (21) free to rotate on the body (B) and the drive means (C) is a motor (M) that revolves the collar. Apparatus as claimed in claims 18, 19 and 20, characterised in that a means (D) for locating the discharge end of the nozzle extends the nozzle (56) from the carriage (21) and drive means (C) and into a predetermined position when the means (A) locating the central axis of the body (B) is operated to centre the same. Apparatus as claimed in claim 21, characterised in that the means (D) for locating the discharge end of the nozzle is a cylinder and piston means (29) disposed on an axis radial to the central axis of the body (B) and carriage (21). Apparatus as claimed in any one of claims 9 to 22, characterised by a shield (75) which surrounds and extends from the front end of the nozzle (56) to form a flame chamber separated from surrounding waters. Apparatus as claimed in claim 23, characterised in that said shield (75) is retractable and is biased into spaced relation to the inner diameter wall (11) of the tubular metal casing (10)(11) by spring means (76) limited by a stop (77). Apparatus as claimed in claim 24, characterised in that the said shield (75) is provided with a wheel follower (82) engageable with the inner diameter wall (11) of the tubular metal casing (10)(11). Apparatus as claimed in claims 23, 24 and 25, characterised in that the shield (75) has a fourth fluid connection (54) and at least one jet opening (80) into the flame chamber to purge the chamber with air from means supplying the same thereto. Apparatus as claimed in claims 18-26, characterised in that the means (A) for locating the central axis of the body (B) concentric with respect to the centre axis of the tubular metal casing (10)(11) comprises longitudinally spaced sets of retractile radially disposed legs (14) extended to by means (16) into positioned engagement with the inner diameter wall (11) of the tubular metal casing (10)(11). Apparatus as claimed in claim 27, characterised in that each set of legs (14) includes three retractile and radially disposed legs (14) extended by cylinder and piston means (16) into positioned engagement with the inner diameter wall (11) of the tubular metal casing (10)(11).

Inventors: DASPIT, RONALD A.
Applicants: DASPIT, RONALD A.
Application year: 1988
Main classification: B23K7
IPC codes: B23K7, F23D14