Abstract: A method for producing a drill shaft for a wet drill bit includes forming N, where N?1, strip materials into a tubular body where the tubular body is integrally joined at strip edges of the strip materials by N connection welds. At least one strip material of the strip materials is provided with at least one recess before the integral joining of the strip edges.

Abstract: Spiral forming methods can be used to join edges of a rolled material along a spiral joint to form conical and/or cylindrical structures. Alignment of the edges of the rolled material can be controlled in a wrapping direction as the material is being joined along the spiral joint to form the structure. By controlling alignment of the edges of the material as the edges of the material are being joined, small corrections can be made over the course of forming the structure facilitating control over geometric tolerances of the resulting spiral formed structure.

Abstract: A mandrel designed for use in the construction of a custom-sized box includes a common platform on which a plurality of peripheral members is independently mounted. Each peripheral member comprises a disc-shaped base rotatably mounted on the common platform, a tongue slidably mounted within a channel formed in the base, and a vertical upright rotatably mounted at one end of the tongue. To construct a box, an elongated continuous strip of material is helically wrapped around the vertical uprights to form a main box body with a plurality of bands. Cutting mechanisms in each upright are actuated to create slots in the main box body that define flaps used to selectively enclose the open top and bottom ends of the box body. By reconfiguring the vertical uprights in the mandrel, a customized box can be constructed that is dimensioned to receive a consumer product with limited wasted space.

Abstract: An electric cable (10) includes at least one composite reinforcement element (1) including one or more reinforcement element(s) at least partially embedded in an organic matrix. A coating (2) surrounds the composite reinforcing element(s) (1). The coating (2) is sealed all around the composite reinforcing element(s) (1). At least one conducting element (3) surrounds the coating (2), where the thickness of the sealed coating (2) does not exceed 3000 ?m.

Abstract: A container is produced from a single-layered, helically bent sheet metal strip. In the strip's upper or lower border region a first helically running border portion of the strip is bent out via a helically running outwardly bent edge with a curved region toward the outside of the container as a protruding flange. A second helically running border portion is in the lower/upper border region. The border regions each border one another adjacently height-wise and are connected to one another in a fluid-tight manner via a continuous, helically running welded joint. The second border portion runs rectilinearly in the plane of the strip and the welded joint has a first and a second weld seam. The first and second weld seams are applied from the outside and the inside of the container, respectively, and the two weld seams are fused to each other in the weld route thereof.

Abstract: A control system for forming a tapered structure includes a sensor providing feedback for a machine for forming a tapered structure including at least three rolls having at least one bend roll and at least two guide rolls. The guide rolls may include rollette banks having a plurality of rollettes. The machine may also include an adjustment mechanism to position at least one of the rolls, where a diameter of the tapered structure being formed is controlled by relative positions of the rolls. The machine may also include a joining element to join edges of a stock of material together as it is rolled through the rolls to form the tapered structure. The control system may also include a controller to receive feedback from the sensor and to send a control signal based on the feedback to the adjustment mechanism for positioning at least one of the rolls.

Abstract: A heat pipe assembly that includes at least one axial groove heat pipe and at least one porous media heat pipe. The porous media heat pipe may be embedded into a flange of the axial groove heat pipe, or embedded into a wall of the axial groove heat pipe, or embedded into another bore of the axial groove heat pipe. The evaporator of the at least one porous media heat pipe may be located remotely and can accept a high heat flux, while a condenser of the at least one porous media heat pipe is attached to the axial groove heat pipe.

Abstract: The invention relates to a tubular helical support (1) for the radial support of resiliently expanded tubing (27), a process and a device (18) for the production thereof, and a tubing arrangement (26) comprising a helical support (1) according to the invention, the helical support (1) being made of at least one extruded element (2), which is wound to form a plurality of windings (11, 12, 13) and the connection portions (7, 8) of which are connected to one another at least in portions by a connection seam (15), preferably formed as a laser weld seam. To produce a helical support (1) which reliably withstands the compression forces of the tubing (27), can easily be removed from the expanded tubing (27), and is easy and cheap to produce, it is provided in accordance with the invention that at least the interconnected connection surfaces (9, 10) of the connection portions (7, 8) of the extruded element (2) are not transparent to laser beams.

Abstract: In a method for producing welded helical seam tubes having optimized tube geometry a metal strip is helically formed into an open seam tube by means of a forming unit and the converging strip edges are welded together, wherein an actual diameter determined on the welded tube is compared with a specific target diameter and a possible deviation lying outside a tolerance threshold is used to correct the actual tube diameter, wherein the strip edges are completely welded in a two stage step, including tack welding as a first step immediately after the shaping to form an open seam tube and thereafter final welding as a second step. The tube diameter is measured after the complete shaping to form an open seam tube and before the final welding. For this purpose, the diameter measuring device is arranged in such a way that either the completely shaped open seam tube or the only tack-welded tube is measured.

Abstract: Cylindrical screens and screen assemblies for use with perforated base pipe or casing for sand control in wellbores have generally longitudinally extending slots punched in the screen. The outer surface of the screen material is deformed below the inner surface causing apertures to form along the longitudinal edges of the slot. The slots are generally longitudinally aligned with the longitudinal axis of the cylindrical screens whether butt-welded or spiral-rolled and welded by determining the angle at which the slots need to be punched to result in such alignment. End caps which connect between the screen and the casing extend over the ends of the cylindrical screen and are welded thereto to minimize sand entry. At least one of the end caps may include an expansion joint to permit relative expansion and contraction between the screen and the casing particularly when used in thermal recovery operations.

Abstract: A separator with a helix assembly that includes a plurality of segments disposed end to end and forming an intermediate casing. Each of the segments has a tubular portion with a first circumferential edge and a second circumferential edge and a helical portion extending from the second circumferential edge. The tubular portions of the segments form an intermediate casing, while the helical portions of the segments form a spiral helix. The helix assembly further includes an inner casing concentrically disposed within the intermediate casing and coupled to the spiral helix.

Abstract: A method for forming a wave form for a stent. The wave form includes a plurality of substantially straight portions and a plurality of curved portions. Each curved portion connects adjacent substantially straight portions. The method includes feeding a formable material between a first die and a second die, the first die having a protruding surface in the shape of the wave form, and the second die having a recessed surface in the shape of the wave form complementing the protruding surface of the first die, pressing the formable material with the protruding surface of the first die into contact with the recessed surface of the second die, and shearing the wave form from the formable material with shearing forces created by the pressing.

Abstract: An apparatus for applying a helical cladding bead to the interior surface of a pipe elbow has a rotor mounted to an elbow carriage so as to be rotatable about a primary axis. The elbow carriage is longitudinally movable parallel to the rotor's rotational axis. A radially-movable elbow collar is mounted to the rotor, and has means for mounting a first end of a pipe elbow. The second end of the elbow passes through a stationary frame with centering means for keeping the elbow's curved centerline tangential to the primary axis. A weld arm, extending from a weld arm carriage into the second end of the elbow, is sinuously configured so that it will not interfere with the elbow. The weld arm is rotatable about the primary axis in coordination with the rotor. A weld head is mounted at the extending end of the weld arm so as to remain spatially fixed regardless of rotation of the weld arm.

Abstract: An apparatus for applying a helical cladding bead to the interior surface of a pipe elbow has a rotor mounted to an elbow carriage so as to be rotatable about a primary axis. The elbow carriage is longitudinally movable parallel to the rotor's rotational axis. A radially-movable elbow collar is mounted to the rotor, and has means for mounting a first end of a pipe elbow. The second end of the elbow passes through a stationary frame with centering means for keeping the elbow's curved centerline tangential to the primary axis. A weld arm, extending from a weld arm carriage into the second end of the elbow, is sinuously configured so that it will not interfere with the elbow. The weld arm is rotatable about the primary axis in coordination with the rotor. A weld head is mounted at the extending end of the weld arm so as to remain spatially fixed regardless of rotation of the weld arm.

Abstract: A tube, which is especially employed for making the main frame tube of a bicycle, is fabricated by means of a 6-4Ti alloy sheet being fed to the forming mold with a feed device, being cold-rolled with the stamping block, winding the circumferential side of the forming mold as a tube blank with a spiral clearance extending along the tube blank, and welding the tube blank at the spiral clearance as a seam of the finished tube. In this way, the fabricated tube has an advantage of providing a high strength to resist being deformed easily.

Abstract: A system and method of forming a continuous strip from a plurality of strips, each strip having a leading end and a trailing end. Embodiments can include a forming apparatus that chamfers at least one of the leading and trailing ends of each strip. The chamfered trailing ends may then be positioned against chamfered leading ends of successive ones of the plurality of strips. Once a leading end and a trailing end are positioned against one another, a first welding apparatus may weld on a first side, from above, the trailing and leading ends positioned against each other to form weld joints. Once at least two strips have been welded together, the strips can constitute the continuous strip. An inverting apparatus can then invert the continuous strip and weld joints. The inversion of the weld joints can be done so as not to create a reverse bend in the continuous strip. A second welding apparatus can then weld on a second side opposite the first side, from above, the inverted weld joints to form weld junctions.

Abstract: A filter element (1) wound from a plurality of filter layers in which the circumferential contour (5, 5?) of a cross-sectional area (4) of the filter element (1) has at least one circumferential contour section (5?) undercutting the envelope contour (6, 6?) of the cross-sectional filter element area (4).

Abstract: The invention relates to a device (1) for cutting or welding tubes (3) or similar workpieces, said device comprising a guiding mechanism which is used to control the cutting or welding torch (17) along a pre-determined line and is provided with a stand-type portal (7). Said portal comprises a through opening (8) into which the workpiece (3) to be machined can be guided in the axial direction. A rotary part (14) can be rotated about the axis of the through opening (8) in a motor-driven manner, guiding a holding arm (16) therewith, which carries the cutting or welding torch (17) on the free end thereof. Said holding arm (16) is fixed to the rotary part (14) and embodied in such a way that the cutting or welding torch (17) moves radially in relation to the axis of the through opening (8) and can be brought into various angular positions in relation to the surface of the workpiece (3).

Abstract: An apparatus for filtering well fluids and method of manufacture is disclosed. The apparatus comprises an inner support, a filter spirally wrapped around the inner support, and an outer support wrapped around the filter enclosing the filter between the inner and outer supports. The filter has longitudinal edges which overlap and the filter is held in place by friction with the inner and outer supports. The method of manufacturing the apparatus comprises continuously and simultaneously wrapping a filter and outer support around an inner support and disposing the filter between the outer and inner supports.

Abstract: A portable apparatus for forming pipe from helical convulsions of elongated sheet metal. A decoiler, rolling portion and pivot are mounted on a trailer, with a rigid frame extending from pivot and being laterally pivotable at the pivot in relation to the trailer. A forming head, cutoff saw, and dump table are mounted on the frame and pivotable therewith so that various diameters of pipe can be formed.

Abstract: Connecting ends on a hose piece comprising several metal layers, in particular a strip wound metal hose piece, are produced by fixing the overlapping metal layers of a hose of larger length or of an endless hose in the region of the point of separation through welding and subsequently cutting off the hose piece from the longer hose or the endless hose. For simple and inexpensive fixing of the metal layers in the region of the point of separation, a welding seam is generated which extends through at least part of the periphery of the hose or about its entire periphery, using roller seam welding. The hose piece can subsequently be separated along the welding seam obtained in this manner, e.g. along its central line, thereby ensuring permanent and reliable fixing of the metal layers in the region of the connecting end.

Abstract: A ribbon of color A metal is combined with a thin layer of soldering alloy, bent and soldered to form a tube, it is then filled with a core of color B metal. The compound is then drawn and/or laminated until it is transformed into a long ribbon or into a wire, externally of color A and internally of color B. The filled ribbon or wire is wrapped like a solenoid around a deformable support, like a metal mesh and stamped into the desired shape. The resulting two faced element is then ground in order to remove, all along a strip and following a line or in dots, the superficial part of color A until the core of color B is revealed. The bi-colored long element is then treated like a single body and allows the realization of precious bi-colored ornamental items.

Abstract: The present invention provides a high strength ?+? titanium alloy pipe not requiring a large amount of cutting and enabling full use to be made of the features of titanium alloy of light weight and high strength and a method for production of the same. Specifically, a high strength ?+? titanium alloy pipe having an outside diameter of at least 150 mm and a wall thickness of at least 6 mm, the ?+? titanium alloy pipe characterized by having a welded seam running in the longitudinal direction of pipe at one location and by having a ratio of the minimum wall thickness to the maximum wall thickness of the portions excluding the weld zone of 0.95 to 0.99. Also, a method of production of a high strength ?+? titanium alloy pipe comprising cold forming a high strength ?+? titanium alloy plate of a wall thickness of at least 6 mm into a tubular shape by the U-O method or press-bending method and welding together the abutted plate edges.

Abstract: Method and apparatus for the manufacture of large-diameter, elongated, generally conical members in a continuous operation.

Abstract: A ribbon of colour A metal is combined with a thin layer of soldering alloy, bent and soldered to form a tube, it is then filled with a core of colour B metal. The compound is then drawn and/or laminated until it is transformed into a long ribbon or into a wire, externally of colour A and internally of colour B. The filled ribbon or wire is wrapped like a solenoid around a deformable support, like a metal mesh and stamped into the desired shape. The resulting two faced element is then ground in order to remove, all along a strip and following a line or in dots, the superficial part of colour A until the core of colour B is revealed. The bi-coloured long element is then treated like a single body and allows the realisation of precious bi-coloured ornamental items.

Abstract: An apparatus and method of manufacturing a wellscreen for subterranean use in oil, gas, and water wells, incorporating numerous automated processes, whereby layers of mesh are continuously sintered to a perforated strip, formed into a tube, placed over a perforated base pipe, and sealed with end rings.

Abstract: A cylindrical helical seamed metal tube wherein the seam thereof is at an angle of between 1 and 25 degrees with respect to the axis of the tube. A method of making the tube comprises the steps of continuously feeding the metal strip into a tubing former to form the metal strip into a helical tube with the leading and trailing edges juxtaposed, the feeding such that the strip longitudinal axis is at a substantially constant acute angle with respect to the tube longitudinal axis of between 1 and 25 degrees. After the tube is substantially formed, applying pressure on at least the leading edge, leading portion, trailing edge and trailing portion in the direction of the cylindrical wall such that same substantially conform to the cylindrical wall. The juxtaposed leading and trailing edges are fused together to form a fused seam, and maintained in a juxtaposed position until the seam cools sufficiently to maintain the juxtaposed position. An apparatus for making the tube is also provided.

Abstract: A cylindrical helical seamed metal tube wherein the seam thereof is at an angle of between 1 and 25 degrees with respect to the axis of the tube. A method of making the tube comprises the steps of continuously feeding the metal strip into a tubing former to form the metal strip into a helical tube with the leading and trailing edges juxtaposed, the feeding such that the strip longitudinal axis is at a substantially constant acute angle with respect to the tube longitudinal axis of between 1 and 25 degrees. After the tube is substantially formed, applying pressure on at least the leading edge, leading portion, trailing edge and trailing portion in the direction of the cylindrical wall such that same substantially conform to the cylindrical wall. The juxtaposed leading and trailing edges are fused together to form a fused seam, and maintained in a juxtaposed position until the seam cools sufficiently to maintain the juxtaposed position. An apparatus for making the tube is also provided.

Abstract: Method for the fabrication of cones of sheet material where the blank includes two curved edges that are circular and have the radius R and r respectively and a common center C. The blank further has two straight lateral edges which are angled in relation to the circular edges. An angle .alpha. between the radius, through a corner and a first straight edge is as great as an angle .beta. between the radius through a second straight edge. A frustum of a cone is obtained from the blank after rolling the cone such that the lateral edges have been united to make a joint that runs helically around the cone.

Abstract: A helical weld servo controller for controlling the diameter of helically formed welded pipes adjusts the auxiliary hold down wheel position and the helix angle based on information provided by transducers regarding outgoing pipe diameter and by a laser vision device which generates weld gap and offset information.

Abstract: Disclosed is a composite overhead cable structure having high seal properties, comprising a metallic pipe, at least one layer of stranded metallic elongated conductor surrounding the outer periphery of the pipe, and an optical fiber cable disposed within and extending throughout the length of the pipe, wherein the metallic pipe comprises at least two metallic pipe sections which are arranged in alignment and connected at their respective confronting terminals having contours complementary to each other and wherein the metallic pipe has a specific structure of connection between the mutually adjacent pipe sections, such that a longitudinal through-weld extends along the entire length of the metallic pipe and such that a connecting turning weld extends between first and second different points on the longitudinal through-weld of the metallic pipe so as to turn around the axis of said metallic pipe, the first and second points being positioned at a distance which satisfies a specific relationship.

Abstract: A method is described for manufacturing helically formed pipe from strip material. One side of the strip material is formed to provide a first side flange that projects substantially 90.degree. relative to the plane of the strip. The opposite side of the strip is formed with a channel that includes a second side flange that also projects substantially 90.degree. relative to the plane of the strip but in the opposite direction from the first side flange. The strip material is then helically coiled while the first and second side flanges are moved into abutting contact. Pressure is then applied radially of the pipe axis, forcing the contacting edges of the flanges together while the flanges are welded, thus forming a rib with a helical weld seam located at or near the line of neutral forces in the rib.

Abstract: Railroad tank cars are provided with spirally wound cylindrical tanks spanning and supported on wheeled trucks with a continuous weld extending the full length of the tank. A steel plate ribbon or strip is spirally wound in the form of a right circular cylinder with a continuous weld bonding the edges of the strip in abutted relation to provide the tank side wall. The open ends of the resulting cylinder tube are closed by welded-on end caps and suitable openings are provided in the tube for manways, vents, valves and the like. A heating coil may be provided on the inside or outside of the tank in intimate contact with the spirally wound ribbon and conventional insulation and jacketing may be provided around the tank. Drop center and center sump tank are provided by cutting the spirally wound tube along a diagonal plane, rotating adjoining sections 180.degree.

Abstract: An apparatus for fabricating multi-layer spiral tubes including first drive means for performing rotation of an inner cylinder around which a web is to be wrapped spirally a slide base moveable along the longitudinal direction of the inner cylinder, the slide base being disposed on a bed so as to be slidable along the longitudinal direction of the inner cylinder, a plurality of pairs of cradles mounted on the slide base for placing the inner cylinder thereon, first depressing rolls for wrapping the web, second depressing rolls for constraining a weld portion of the web, an automatic gap detector for detecting a gap between adjacent edge portions of the wrapped web, an automatic welding machine for welding edge portions of the wrapped web, an automatic grinding machine for grinding excess metal of welding, an automatic defect hunter for detecting defects in the weld portion, a web feed table for feeding the web, second drive means for moving the web feed table, and a central control unit is provided and couple

Abstract: A method of manufacturing a cylindrical billet having a predetermined length useable as raw material for producing a pipe. This method is practiced by way of the steps of drawing a cast slab from a casting mold on a continuous casting stand, spirally winding or cylindrically bending it around a rotating mandrel, joining together both end faces of the wound or bent cast slab to a cylindrical body and cutting it to a predetermined length. Two or more cast slabs may be used for forming the cylindrical body. Two rectangular cast slabs may be used as starting material which are subjected to roll forming and thereafter are cut to the predetermined length. They are then press worked to form a recess having a semi-circular cross-sectional configuration whereby a cylindrical body is constituted by assembly thereof in a superimposed relation.

Abstract: A structural vessel includes helically curved inner and outer spaced strips of material each having a plurality of helical turns, with contiguous edges of each two successive turns of the inner and outer strips being seamed together, and a helically curved structural beam disposed between the strips and secured thereto along their turns. A floatable work housing is provided for vessel fabrication, the housing having a sealed opening through which the completed portion of the vessel progressively extends and is floated on a body of water to avoid a need for external supports and bearings.

Abstract: In the manufacturing of a spiral pipe, there is first determined a maximum curvature which should be imparted to a strip of pipe forming material in order that a desired residual moment will be imparted to the finished pipe after the strip bent to the maximum curvature is allowed to spring back from the bent condition, which maximum curvature is determined based on the thickness, Young's modulus and yield stress of the strip, the desired curvature of the finished pipe, and the residual moment to be imparted to the finished pipe. By adjusting the position of three rows of forming rolls positioned at the apexes of a triangle, the flat strip is continuously bent into a spiral that has the thus determined maximum curvature.

Abstract: A spirally fluted metallic heat transfer tube is disclosed wherein the finished tube has improved heat transfer performance through the provision of a predetermined number range of multiple start continuous helical flutes formed along its longitudinal length, the flutes having specific helix angle relation and flute height to tube hydraulic diameter ratio so as to establish a ratio of thermal diffusivity to momentum diffusivity greater than 1.

Abstract: A method of and device for producing multi-layer pipes by helically winding a plurality of bands loosely arranged one above the other, which are individually withdrawn from a supply, straightened out, trimmed, and in the form of a band loop are conveyed to the forming station at the respective angle of lead-in corresponding to the respective pipe diameter, whereupon the layers are together welded to form a pipe strand which is subsequently cut into individual pipes. All bands are supplied and advanced independently of the irregularities of the respective longitudinal band edge shape in steadily straight lead-in directions, and all band edges are machined together to a possible maximum width in coordination with each other whereupon the bands are driven together while the welding gap is controlled in conformity with their band edge shape merely by pivoting the pipe.

Abstract: A thin perforate, helically wound welded edge tubing is used as a filter core for a roving wound filter. The slightly roughened external edges of the spirally formed welded joint greatly adds to the ability of securing the fiber roving to the tube and prevents relative slippage therebetween. Also, the invention comprehends an apparatus for, and a method of making the helically seamed tube by first drawing a sheet metal from a supply and raising two lateral edges thereof to form flanges. The material can be guided in a helical path by engaging the inside of the flanges so that the trailing edge abuts the leading edge. The abutted edges are heated so that the flanges themselves provide the filler for a weld on the exterior surface thereof. Drive rollers are provided to move the welded tube from the welding area and to torque the tube to prevent edge separation prior to the cooling of the weld.

Abstract: A method of joining the stripped ends of electrical wires and screw-on connectors for performing the method. The method includes bunching the stripped ends of wire, inserting the bunched wires into a distortable relatively nonexpandable wire retainer having an inwardly tapered thread, rotating the wires and wire retainer relative to one another to feed the bunched wires into the wire retainer, applying torque to the bunched wires and the wire retainer to cause the wire retainer to compress the wires into contact with one another and form a thread thereon, supporting the wire retainer during application of the torque in a manner which permits the wire retainer to freely distort without substantial expansion to thereby accommodate the wires as the wires are forced into the small end of the tapered thread, and covering the wire retainer and retained wire with an insulator. A screw-on wire connector which includes an insulating cap with a bore open at one end for the reception of the stripped ends of the wires.

Abstract: Tapered spiral tube in continuous lengths is fabricated with an alternating increasing and decreasing diameter, the length being severed at the locus of change. The taper may be straight, convex or concave, the tube being produced from strip-stock which is squeezed between biassing rollers whereby one or other edge is thinned, and as a consequence lengthened and convexly curved. The entire fabricating process is automatic, being predetermined by templet means and monitored by feed-back measures felt by the tube while being fabricated.

Abstract: Method and apparatus for producing a large diameter storage tank from strip metal. The strip is fed to a support assembly arranged circularly on a base and which supports the strip vertically in a helical path. The upper edge of the strip is bent into a right-angled bend which is aligned with the unbent lower edge of the helical turn immediately thereabove. The two aligned edges are welded together. The right-angled bend produces a helical outwardly extending structural fin on the outside of the storage tank.

Abstract: In winding a continuous strip of sheet metal having chamfered edges into a helical seam pipe, the chamfered edges define an inside seam and an outside seam in the pipe. Initially, after forming the pipe, a tack weld is formed in the outside seam and then a finish weld is provided in the inside seam. Next, the pipe is cut into lengths and finally a finish weld is made in the previously tack welded outside seam. The cross sectional area of the inside seam is kept to a minimum and though different thicknesses of strip can be used for forming the pipe, the cross sectional area of the inside seam is maintained a constant over the range of strip thicknesses used to assure that the inside seam is finish welded in as short a time as possible with the pipe moving axially at the highest possible speed.

Abstract: In forming a metal plate or the like into a helical seam pipe, the plate is deformed by bending rolls each made up of individual forming rolls. The forming rolls are exposed to shearing forces if the plate varies its direction of travel toward the forming rolls. To prevent the continued presence of shearing forces, the forming rolls are pivotally mounted on a support which is displaceably guided within a holder and an adjusting mechanism is connected to the support and the forming rolls to adjust the setting angle of the forming rolls in accordance with the direction of travel of the plate toward the forming rolls.

Abstract: Heat transfer tubes are provided internally with extended surfaces to improve heat transfer between a fluid within the tube and a fluid outside of and in contact with the tube. A flat sheet of metal is provided with extended surfaces which are welded to one side of the sheet, so that a tube with internal extended surfaces can be formed by bending the sheet so that it envelopes the surfaces and welding sides of the sheets together.

Abstract: A method of producing a corrugated flexible tube wherein a corrugated profiled strip having multiple corrugations is wound in a helical path such that its edges overlap and then the overlapped edges are tight welded together, preferably by electrical resistance welding, such that every welded corrugation of the resultant corrugated flexible tube is followed by at least one unwelded corrugation.