MXPA06000065A - Apparatus for rectifing round pipe and tubing - Google Patents

Abstract

Apparatus for reducing the diameter, rounding or straightening of pipe or tubing by rolling comprising a plurality of closely and equally -spaced, long, narrow, parallel-cylindrical rollers arranged in a parallel -cylindrical array through which said pipe or tubing is passed at a constant linear speed, said rollers being skewed to displace their central contact zones radially inwards bringing them into forceful contact with the external surface of said pipe or tubing, and being rotated to cause said central contact zones to describe continuous, parallel, overlapping, helical paths along the external surface of said pipe or tubing and thereby to progressively apply locally to the whole of the external surface of said pipe or tubing a compressive force in excess of the yield strength of its material, causing said pipe or tubing to adopt a set at a smaller diameter.

Description

APPARATUS FOR RECTIFYING ROUND TUBES AND PIPES Description This invention relates to methods and apparatuses for rectifying by reduction the diameter of round tubes or pipes with the side effects of straightening and rounding. More particularly, it relates to such methods and apparatuses that employ a plurality of rollers for this purpose. For a variety of reasons, in the manufacture of tubes and pipes by rolling a tubular form from a flat strip or plate and welding the abutting edges, it is impossible to maintain precise control of the finished diameter. Particularly in larger diameters and where lighter gauge material is used, for example in diameters above 150 millimeters or where the wall thickness is less than 2% of the diameter, pipes and tubing manufactured in this way may not be perfectly round. Some variation in righteousness is also frequently experienced. It is well known that standards for some forms of pipes and pipes prescribe quite liberal tolerances. Many applications exist in which pipes and tubing must meet precise specifications in relation to diameter, roundness, and straightness and a variety of methods have therefore been developed to correct defects in these criteria. Where the diameter of the tubes or pipes has been increased, it is common to pass a cylindrical die of some suitable hard material and have an external diameter somewhat larger than the internal diameter of the tubes or pipe through the lumen of the pipe or tube to stretch it. Where more than a minor correction is required, consecutive steps of increasing diameter dies may be required, internal surfaces of the pipe or tube lumen may require lubrication, cutting of internal surfaces is common and some degree of wall thinning will occur. The process has the advantage of being operable on a continuous basis. In another method, the internal diameter of the pipe or tubes is increased by holding the interior of short lengths under hydraulic pressure to expand it into a female die enclosing. The use of this method is usually confined to short lengths of pipe or tubes and has the disadvantages of slowness and the fact that it can not be operated on a continuous basis. Both methods are well known in the art. When the diameter of pipe or tubes is required to decrease, it is common to roll it down by passing the pipe or tubes through a plurality of concave rollers arranged such that their extended diameters are at a common point and their collective concavities more or less forming a complete circle slightly smaller than the final diameter of pipe or tubes required. Equally separated rollers are supported on arrows parallel to tangents with the surface of the pipe and tubes and are driven in rotation while the pipe or pipes to be re-dimensioned are fed between them and thereby cold-worked to a smaller diameter. Unless the pipe or tubes are stretched over time, some degree of wall thickening will occur. An example of this method is taught in US Pat. No. 5,533,370. This method is intended for use with only pipes or tubes of smaller diameters and the fact that the method includes the provision for final dimensioning being carried out by removing the pipe or rolled tubes through a female dimensioning die is indicative of the control limited working diameter available. Disadvantages of this method are the fact that only relatively small decreases in diameter can be achieved in a single step, usually from the 0.2 to 0.4 mm degree, that what is effectively a cleaning action of the sides of the roller concavities can tear or damaging the external surfaces of the pipe or tubes (an important factor in stainless steel products, and the fact that the method is relatively ineffective in relatively thin wall pipes or tubes, long. The tearing or damage of the external surfaces is particularly pronounced in larger diameter pipes or tubes where the method is normally carried out using only two rollers having deep concavities. Obviously, as suggested in the cited example, the diameter of the pipe or tubes can be reduced by removing it through the female dimensioning die. Where this method is used, the pipe or tube may require lubrication, the external surface of the pipe or tubes is frequently cut by asperities in the die or taken by the die and some wall thickening and elongation may occur. An example of this method is taught in US Pat. No. 4,057,992 in which both internal and external data are used in what is usually a second or third manufacturing operation. Another example of diametral reduction by rolling, in this case described in roll formation, is that taught by US Pat. No. 6,233,991 in which a short length of pipe or tubes is rotatably supported by clamps only at the ends and a plurality of cylindrical rolls. they are carried to hold against the outer surface of the length of the pipe or tubes while rotating, thereby reducing their diameter and, if required, returning it to a tapered shape. The method is applicable only to short lengths of pipe or tubes and obviously can not be operated as a continuous process. Relevant to the present invention is US Pat. No. 4,242,894 in which thin-walled metal tubing is formed from a solid blank in an Assel laminate mill. In this case, provision is made to vary the wall thickness of the tubes formed by means of adjusting the radial positions of a plurality of forming rollers. Adjustment is effected by increasing the bias of short arrows before which the forming rollers are rotatably supported, whereby the rollers are moved radially inwardly or outwardly. The ends of short arrows are rotatably supported in suitable bearings accommodated within the ball and cavity joint ball parts, which ball parts move in complementary cavities to allow bias of the arrows. The rollers are short and are provided with shoulders which work in the target from which the tubes are formed. In many tube rolling methods, such as that taught in US Pat. No. 4,827,749, a mandrel is inserted into the lumen of a tube to be rolled and the tube is worked by a plurality of rollers against the mandrel. Applications are also common in which tubing or laminated tubes are made by removing one piece of tubing or tubes within the lumen of another. Where, for example, the pipe or inner tube is made from a polymer material, it is common to temporarily reduce its diameter by passing it between concave rollers or through a die of female dimension in the manner described and, when positioned Inside a larger diameter pipe or tube, expand it by applying internal fluid pressure to make a tight fit inside the pipe or outer tube. Additionally, to ensure a more secure capture of the pipe or inner tube, the pipe or outer tube can subsequently be reduced in diameter using one of the described methods. Where the pipe or tubes both inside and outside are metal, the interior is captured simply by reducing the diameter of the exterior. The object of the present invention is to provide a method and apparatus for reducing the diameter of the pipe or tubes; which can easily be adjusted precisely to produce a precise finished diameter; which can be operated in continuous or discrete lengths of pipe or tubes; which can be self-corrective; which can also provide a straightening effect; which acts without damaging the external surface of the pipe or tubes; which is capable of making a greater degree of reduction in diameter in a single step than other systems; which leaves the tubing or tubes properly round; which can be combined in a multi-stage operation; which act without the need to lubricate the pipe or tubes; and which is effective in treating a full range of diameters in both thin and thick wall pipes or tubes. According to the present invention, the diameter of pipe or tubes is reduced by passing it through a rotating apparatus comprising a support cylinder in which a plurality of cylindrical rollers separated in a closed and equivalent manner are provided, biased, long narrow, parallel, rigid, hard material, which are carried towards support on the external surface of the pipe or tubes as they pass through said apparatus. Said rollers are supported in a cylindrical arrangement with their ends in graduated circles of equal diameters and rotatably supported in suitable bearings provided in the end flanges of said support cylinder, said end flanges being provided with openings to allow entry and exit of the pipe or tubes to be treated. One or both of said end tabs are capable of rotary movement within the ends of said support cylinder, thereby adjusting the degree of bias of said rollers which, although displaced relative to the longitudinal axis of said support cylinder, remain in planes parallel to said longitudinal axis. Said bearings of said rollers are themselves supported in partially spherical bushings which, in turn, are accommodated within complementary cups formed in said end flanges such that said rollers can continue to be rotatably supported in said end flanges such when They are in their biased positions. Said support cylinder is itself supported rotatably in one or more bearings that allow it to rotate about its longitudinal axis, driven by a suitable traction motor. In the operation, the degree of bias of said rollers is adjusted to bring centrally located, narrow contact areas of the rollers to bear against the outer surface of the pipe or tubes with a desired force. As said pipe or tubes pass at a constant speed through said cylindrical roller arrangement, said support cylinder is rotated by its traction motor, causing said contact zones of said rollers to describe continuous, parallel, overlapping trajectories , in the form of a helix, along the external surface of said pipe or tubes, locally applying a compressive force to said pipe or tubes in excess of the yielding force of its material and thereby causing said pipe or tubes to adopt an assembly to a smaller diameter. The passage of said contact areas of said rollers on the outer surface of said pipe or tubes causes the surface to be attractively polished without damage, any lack of roundness of said pipe or tubes being corrected simultaneously and, if said pipe or tubes required straightening , its restriction in correct alignment as it passes through said rollers would effect this. The various aspects of the present invention will be more readily understood by reference to the following description of the preferred embodiments given in connection with the accompanying drawings, in which: the figures la, Ib and l are partial cross-sectional views of said support cylinder showing several positions of one of said cylindrical arrangements of said rollers; Figure 2 is a cross-sectional view of said support cylinder and said pipe or tubes to be treated -If- showing the arrangement of some of said cylindrical arrangements of said rollers in relation to said pipe or tubes to be treated; Figure 3 is a longitudinal cross-sectional view of said support cylinder, its support bearing and said pipe or tubes to be treated, said rollers having been erased for clarity of presentation; Figure 4 is an end view of the components illustrated in Figure 3; Figure 5 is a longitudinal cross-sectional view of support means at one end of one of said rollers; Figure 6 is a side view of the complete apparatus with said pipe or tubes to be treated passing through it; Figure 7 is a longitudinal cross-sectional view of alternative means for supporting said rollers; Figure 8 is an end view of said support cylinder showing calibration detail; Figure 9 is a partial side view of the central part of said roller showing detail of alternative figure formation; Figure 10 is a partial side view of the central part of said roller showing another detail of alternative figure formation; Figure 11 is a side view of a typical assembly of said rollers in cylindrical arrangement with all the support means removed for clarity of presentation; Figure 12 is an end view of the assembly of said rollers illustrated in Figure 11. With reference to Figure 1, the roller 3 is rotatably supported within the support cylinder 1 with its axis placed in the graduated circle 2 and parallel to the axis of said support cylinder. With reference to figure lb, the same roller is shown with its ends biased 15 ° on each side of the previous position. It can be seen that the distance 4 from the center 5 of said support cylinder to the contact area 6 of said roller has been reduced. With reference to Figure 1, said roller is shown with its additional 15 ° skewed ends and distance 4 can be observed by being further shortened. It can be seen from the figures that the bias of said rollers can be used to bring their central contact areas towards forced contact with the outer surface of said pipe or tubes to be treated. Obviously, said rollers can be made solid through their lengths or made with solid and partially hollow ends in their middle parts. With reference to Figures 2, 11 and 12, partial and complete sets of rollers 3 in cylindrical arrangement are illustrated, said rollers being rotatably supported within the support cylinder 1 with their shaft ends placed in graduated circles 2 of equal diameter. The biasing of said rollers has led to the contact areas 6 towards contact with the external surface of the pipe or tubes to be treated 7. In the preferred embodiment, said rollers are made with a minimum practical diameter of equal proportion with a particular application to provide the maximum number of rollers in each said cylindrical arrangement. This normally results in said rollers having a diameter of about 20% of that of the pipe or pipes to be treated, for example, 18 rolls with a diameter of 28 millimeters are used in an arrangement for treating pipe or pipes with a diameter of 150. millimeters With reference to Figure 3, the pipe or tube to be treated 7 is illustrated by passing through openings 8 in end flanges 9, 19 of the support cylinder 1 in the direction shown by the arrow 23. A typical position of the axis of one of said cylindrical roller arrangements is illustrated by dashed line 18, supporting provisions for this roller in end flanges 9, 19 having been cut in the figure. The end flange 19 is fixed at one end of said support cylinder and the end flange 9 is captured at the end of said support cylinder between supports 20., 21 while remaining free to be displaced in a rotating direction to bias said rollers. The support provisions (not shown) for the ends of said rollers are accommodated in the openings 10 provided in said end flanges of the support cylinder. The bearing 15 is placed on or close to a plane passing through the contact areas of said rollers. The mounting flange 12 is provided on the outer outer surface of said support cylinder and attached thereto with suitable fastening means is a radial network 13, the periphery of which is formed on an inner part of a bearing housing 15. The cylindrical pulley 14 is formed on one side of said radial flange positioned towards its periphery. The radial mounting flange 22 is provided with holes 17 for mounting joints (not shown) and its inner periphery is formed towards an elongate extension 16 which incorporates an outer portion of a bearing housing 15. The mounting flange 22 is fixed with fasteners suitable for a support structure (not shown) and the support cylinder 1 is driven in a rotary direction by tensile forces applied to the pulley 14 through a suitable band (not shown). In alternative embodiments, said pulley is replaced with a gear or gear (not shown) and said support cylinder is driven in a rotary direction by tensile forces applied through one or more suitable chains or gear. As the pipe or tubes to be treated pass through the interior of said support cylinder and through said cylindrical roller rotary arrangement (not shown), said contact areas of said rollers pass over the external surface of said pipe or tubes following continuous, parallel, overlapping trajectories, in the form of a helix, a typical one of which is indicated by the arrow 24. It can be easily demonstrated that the energy required to drive said rollers against said pipe or tubes is sufficiently low and, even When said pipe or tubes are being worked hard, it is normally considered less than the energy required by conventional methods. With reference to Figure 4, the end flange 9 is restricted in a rotary direction by struts of adjustable length 33, the inner ends of which are pivotally joined to short arrows 34 formed in the end flange 9 and the outer ends of which are pivotally joined to short arrows 35 formed at the ends of posts 32 fixed to the outer end surfaces of said support cylinder. The bias of said rollers is effected by lengthening or shortening said struts, with which the end flange 9 moves in a rotational direction relative to said support cylinder. With reference to figure 5, the roller ends 3 are provided with tapered section 27, the end of which is formed towards the arrow 28. The arrow 28 is rotatably accommodated in the needle bearing 29 which, in turn, fits into the partially spherical hub 26. partially spherical bushing 26 is accommodated within the divided cup 25 which, in turn, is accommodated within the opening 10 provided in the end flange 9. The bearing 29 is captured in the arrow 28 between the support 36 and the cover retention 30, said retaining cap being attached to the end of said arrow by suitable fastener 31. Suitable means (not shown) are provided for the lubrication of said roller support means. Said divided cup is provided with external flange 37 by means of which said divided cup is held in place in opening 10 by suitable joining means (not shown). The openings on either side of said divided cup are adequately relieved to provide the required freedom of movement of the roller 3. The arrow 28 and the needle bearing 29 are made long enough to accommodate the axial displacement of the roller 3 caused by an increase or decrease in its degree of bias. In an alternative embodiment (not shown), the arrow 28 and the needle bearing 29 are positively captured in the partially spherical bushing 26 and the axial displacement of the roller 3 caused by an increase or decrease in its degree of bias is accommodated by axial displacement of the end flange 9 within the end of the support cylinder 1, said end flange being restrained against rotational displacement relative to said support cylinder by tabs, ears or the like (not shown) suitable in a supplementary provision of bonding in the other. With reference to Figure 6, the assembly illustrated in Figures 3 and 4 is mounted on a movable frame 38. Said movable frame is slidably supported by clamps 43, 44 resting on linear bearings 41, 42 moving on rails 39, 40 fixed to the upper surfaces of the fixed frame 45. Tubing or tubes to be treated 7 are illustrated by passing through the support cylinder 1 and its extension is supported on suitable supports (not shown). The pivot shaft 46 is fixed to a lower structural member of said moving frame towards one of its sides and the valve 48 is fixed to a lower structural member of said fixed frame towards the second side of said movable frame. A link 49 connects the operating lever of said valve with said pivot arrow such that, as said movable frame moves along rails 39, said valve is progressively opened, said valve being completely closed at the displacement limit on the left hand side. (as illustrated) of said movable frame. A supply of compressed air at a suitable pressure is connected to said valve through the air line 47 and air is supplied from said valve through the flexible air line 50 to an air motor 51. Said motor air urges the pulley 52 through the reduction transmission case 54, said pulley being connected to the pulley 14 by the web 53 to urge the support cylinder 1 in a rotating direction.

Proper reinforcement is provided, as required, to urge said movable and fixed frames. In operation, as said pipe or tubes pass to said apparatus from a tube-forming mill, friction forces applied through the contact zones of said rollers act to move said movable frame along the rails 39, 40, thereby partially opening the valve 48 and activating the air motor 51 to drive the support cylinder 1 in a rotating direction. Progressive displacement of said movable frame occurs until said air motor has reached an operating speed equal to the forward speed of said pipe or tubes. Further displacement of said movable frame then ceases. If the advance speed of said pipe or tubes is reduced for some reason, the forces generated by said rollers before said pipe or tubes act to move said movable frame back to its resting position, thereby closing the valve 48 somewhat and reducing the speed of operation of the air motor 51 and thereby the speed Rotation of the support cylinder 1. With reference to Figure 7, in an alternative embodiment, the rollers 3 are rotatably supported in needle bearings 56 accommodated in bores 73 provided in supports 58 formed in the ends of mounting yokes 59 Each said mounting yoke is supported on the arrow 64 pivotally supported on the bearing 63 provided in the wall of the support cylinder 1 and held in place by Belleville washers 65, washer 66 and circular clamp 67 or other suitable fastener. The rollers in said cylindrical arrangement are simultaneously biased by force applied through slant rings 60 which are pivotally connected to pivots 61 provided at the ends of said yoke and are held in place by circular clamps 62. Pressure washers 57 are provided. between the ends of the rollers 3 and the inner surfaces of the supports 58. Said support cylinder is increased in diameter as required to accommodate the described arrangement. The described arrangement is obviously suitable for treating only a diameter of pipe or pipes and, in an alternative embodiment (not shown) used to treat different diameters, the outer parts of arrows 64 are suitably threaded to link ball nuts that are driven by one or more stepper motors suitable for simultaneously moving all said rollers racially inwards or outwards. The use of screw and ball nut arrangements in such applications is well known and obvious. With reference to Figure 8, an index mark 68 is provided on the face of the end flange 9 and calibration markings 69 are provided on the end of the support cylinder, said markings facilitating the bias adjustment of said rollers. Obviously, the arrangement described is optionally capable of being reversed.

With reference to Figure 9, in an alternative embodiment, the arrow 3 is provided with a convex, narrow, centrally located portion 70 to allow a more localized force to be provided by said roller to said pipe or tubes to be treated . With reference to Figure 10, in an alternative embodiment, the arrow 3 is provided with a concave portion, centrally located, 72 to allow a more dispersed force to be provided by said roller to said pipe or tubes to be treated. With further reference to Figure 6, said fixed frame is fixed to the floor 74 with suitable fasteners. Where required, said fixed provisions incorporate lifting means (not shown) to accurately align the apparatus with the axis of the pipe or tubes 7 emerging from a pipe forming mill (not shown). Said lifting means can be operated to create a straightening effect of said pipe or tubes. In a first embodiment, said lifting means are manually operated. In an alternative embodiment, sensors (not shown) are used to detect the straightness or otherwise of said pipe or tubes and, as required, one or more stepper motors (not shown) are used to operate said lifting means to correct any deviation of rectitude. A programmable logic controller or other microprocessor-based device is used to process data from said sensors and control the operation, as required, of said stepper motors. In another alternative embodiment (not shown), said fixed frame is fixed permanently to the floor 74 and the mounting flange 22 is supported on linear bearings slidingly sliding on fixed rails to the vertical members of said movable frame, said Linear bearings being displaced by screw and ball nut arrangements driven by one or more stepper motors. Said stepper motors are used to drive said screw and ball nut arrangements to correct any deviation of said pipe or straightness tubes. A programmable logic controller or other microprocessor-based device is used to process data from said sensors and control the operation, as required, of said stepper motors. With reference to Figures 3 and 6, in an alternative embodiment (not shown), the air motor 51 is mounted directly to the cylindrical extension 16 and urges the support cylinder 1 in a rotating direction through one or more bands. , chains or gears linking pulleys, gears or gears formed in the pulley 14 or on the external surface of the support cylinder 1. In this embodiment, said movable frame is redundant and said apparatus is simply fixed to vertical members of said fixed frame . In other alternative embodiments (not shown), said air motor is replaced by another form of traction motor in the form of a hydraulic motor, a stepper motor or another form of controllable speed electric motor. In this arrangement, the speed of advancement of said pipe or tubes is detected by one or more encoders joined to form rollers in said tube-forming mill or in a maneuvering wheel that travels in said pipe or tubes. A programmable logic controller or other microprocessor-based device is employed to process data from said encoders and control the operation, as required, of said traction motor by urging said support cylinder in a rotational direction. In an alternative embodiment (not shown), said apparatus is made in a multi-stage form with two or more of said units operated in tandem such that one or all of the units are used to reduce the diameter of said pipeline or tubes, correct their lack of roundness or straighten it. Said units are optionally operated with a common rotation direction or with alternative units rotating in the opposite direction. It will be appreciated from further inspection of the figures the, lb, le and 2 that the axes of said cylindrical roller arrangements of consecutive units, regardless of their settings, will always be co-linear. At the same time, the speed of advance of said pipe or tubes through consecutive units will be correct regardless of said bias adjustment of said rollers. This is a result of the fact that, as the degree of bias of said rollers increases, which would tend to increase the axial component of the vector triangle representing the speed of advance of said pipe or tubes, the rotating component is automatically decreased in compensation. As a result, said apparatus is very well suited for operation in the form of multiple stages. It should also be noted that the axial forces imparted to said pipe or tubes by operation of said apparatus are high and no other means of propulsion or urging in an axial direction is required to be applied to said pipe or tubes during their passage through said apparatus. In multi-stage arrangements of said apparatus, the axial forces applied thereto to said pipe or tubes are optionally used to carry material through a tube-forming mill positioned upstream of said apparatus and significantly reduce the energy required to drive said apparatus. tube forming mill. Obviously, said apparatus can optionally be used to work on continuous lengths of pipe or tubes being delivered directly from a tube-forming mill or before discrete lengths of pipe or tubes sequentially loaded into said apparatus. With further reference to Figure 4, in an alternative embodiment (not shown), one or more stepper motors mounted on the outer surface of the support cylinder 1 are used to adjust the lengths of the screw and nut arrangements balls (not shown) used in place of the adjustable length struts 33. Sensors are provided to detect the precise corrected diameter of said pipe or tubes and a programmable logic controller or other microprocessor based device is used to process data from said sensors and controlling the operation, as required, of said stepper motors. Energy and control signals are supplied to said stepper motors through slip ring provisions and control signals are optionally transmitted through wireless connections. Means of detection in the form of opposed pairs of rollers attached to the inner ends of linear transducers arranged radially are used to measure the finished diameter of said pipe or tubes emerging from said apparatus, said rollers being urged into contact with said pipeline or tubes by suitable springs. In a second embodiment, detection means in the form of a laser micrometer are used to measure the finished diameter of said pipe or tubes emerging from said apparatus. In a third embodiment, detection means in the form of opposite pairs of proximity sensors, each sensor measuring the space between its reference surface and the external surface of said pipe or tubes are used to measure the finished diameter of said pipeline or tubes emerging from said apparatus. With further reference to Figure 3, it will be readily appreciated that the support cylinder 1 with its said roller array can be made to be easily detectable from the radial network 13 through the use of quick release links (not shown) and replacing said support cylinder with its said roller arrangement installed in place to accommodate said pipe or tubes of a different diameter. The rolling process carried out by said apparatus provides precise control of the external diameter of pipe or tubes; does not require lubrication of said external surface of said pipe or tubes; it requires only low energy for its operation; leaves said external surface of said pipe or tubes polished and easily refined; is not limited by the diameter, length or wall thickness of said pipe or tubes; it can be operated with a higher linear velocity of said pipe or tubes than the output speed of a tube-forming mill and the two thus can be operated together; it can be carried out by multiple said rolling units operated in tandem; exerts a rounding and straightening effect before said pipe or tubes; it can be operated under automatic control; it can be used with continuous lengths of said pipe or tubes or with discrete lengths; and provides a greater reduction of external diameter of said pipe or tubes per step than conventional rolling processes.

Claims (56)

1. CLAIMS 1. Apparatus for reducing the diameter, rounding or straightening pipe or tubes by rolling, comprising: (a) a plurality of parallel, cylindrical, narrow, long rolls, spaced close and equidistant, in a parallel cylindrical arrangement, said supported rolls rotating in bearing means provided in end flanges of a support cylinder, the ends of said rollers being placed in graduated circles of equal diameter, said bearings being supported in partially spherical bushings allowing angular displacement of the ends of said rollers in relation to said end tabs, and one or both of said end tabs being rotatably movable to each other in said support cylinder; and (b) openings in said end flanges allowing said pipe or tubes to continuously advance through said rollers in a coaxial path with the axis of said cylindrical arrangement; and (c) means for adjusting the relative positions of the end tabs in said support cylinder to biasly displace said rollers to thereby move said central contact areas radially inward toward forced contact with the external surface of said pipe. or tubes; and (d) bearing means for rotatably supporting said support cylinder; and (e) pulling means for driving said support cylinder in a rotating direction, thereby causing said central contact zones of said rollers to pass over and work against the external surface of said pipe or tubes advancing continuously; and (f) detection means for detecting the linear velocity of said advancing pipe or tubes, the straightness of said pipe or tubes, the speed of rotation of said supporting cylinder and the finished diameter of said pipe or tubes, - and ( g) control means for controlling the speed of rotation of said rollers in relation to the speed of advance of said pipe or tubes, the height of said support means and said bias adjustment of said rollers; and (h) support means for supporting said support cylinder, said end flanges, said rollers, said adjusting means, said bearing means, and said traction means such that said axis of said cylindrical arrangement of said rollers is maintained co-linear with said axis of said pipe or advancing tubes. An apparatus according to claim 1, wherein said rollers are made of a strong, hard material, and they become completely solid or solid at their ends and voids through their central parts. An apparatus according to claim 1, wherein two or more of said cylindrical arrangements of said rollers are arranged and operated in tandem to treat said length of advancing pipe or tubes. 4. An apparatus according to claim 3, wherein said cylindrical arrangements of said rollers alternately rotate in opposite directions. An apparatus according to claim 1, wherein said traction means for driving said support cylinder in a rotating direction take the form of an air motor driving through a band, chain, or gear. An apparatus according to claim 1, wherein said traction means for driving said support cylinder in a rotating direction takes the form of a hydraulic motor driving through a band, chain, or gear. An apparatus according to claim 1, wherein said traction means for driving said support cylinder in a rotating direction take the form of a stepper motor or other form of controllable speed electric motor driving through a band, chain, or gear. An apparatus according to claim 1, wherein said central contact zones of said rollers work against the external surface of said pipe or tubes advancing continuously in a series of continuous contact paths, parallel, overlapping, in the form of a helix. 9. An apparatus according to claim 1, wherein the energy required to treat said pipe or tubes is significantly less than that required for conventional tube rolling processes. An apparatus according to claim 1, wherein the relative positions of said end flanges with each other are adjusted by means of one or more struts of adjustable length, the two ends of each of which are pivotally fixed respectively to said end flange and said support cylinder. 11. An apparatus according to claim 10, wherein the length of said strut is manually adjusted by means of screwing a threaded male part into a threaded female part and closing the adjusted length with a locking nut. 12. An apparatus according to claim 10, wherein the length of said strut is adjusted through the use of a screw and ball nut arrangement driven by a stepper motor. 13. An apparatus according to claim 1, wherein energy and control signals are transmitted to devices supported on the movable parts of said apparatus through slip ring means. 14. An apparatus according to claim 1, wherein control signals are transmitted to devices supported on the movable parts of said apparatus through wireless means. 15. An apparatus according to claim 1, wherein said support means comprises a movable frame slidably supported on linear bearings moving on fixed rails to a fixed frame, said movable frame being displaced in a linear direction by the combined forces generated by the action of said rollers and by the linear movement of said pipe or tubes, detection means being provided between the two said frames to detect the linear displacement of said movable frame and thereby to regulate the speed of operation of said traction means. 16. An apparatus according to claim 5, wherein the speed of operation of said air motor is controlled by control means in the form of a pneumatic valve actuated by displacement of said movable frame relative to said fixed frame. An apparatus according to claim 1, wherein said support means are adjusted in height to maintain said axis of said cylindrical arrangement of said rollers co-linear with the axis of said advancing pipe or tubes. 18. An apparatus according to claim 17, wherein said support means are raised or lowered by means of manually operated screw jacks. 19. An apparatus according to claim 17, wherein said support means are raised or lowered by lifting means incorporating screw and ball nut arrangements and operated by stepper motors. An apparatus according to claim 18, wherein said detecting means is used to detect the straightness of said advancing pipe or tubes and said control means is used to control the operation of said stepper motors to adjust the height of said support means. 21. An apparatus according to claim 1, wherein said support means takes the form of only a fixed frame and said support cylinder, said end flanges, said rollers, said adjustment means, said bearing means, and said traction means are movably supported on linear bearings traveling on vertically arranged rails which allow said axis of said cylindrical arrangement of said rollers to be kept co-linear with said axis of said advancing pipe or tubes. 22. An apparatus according to claim 21, wherein the position of said linear bearings in said vertical rails is adjusted by screw and ball nut arrangements driven by stepper motors controlled by said control means. 23. An apparatus according to claim 1, wherein said detecting means includes one or more encoders driven by forming rollers in said tube-forming mill or by a maneuvering wheel moving in said tubing or tubes. 24. An apparatus according to claim 1, wherein said detection means includes measuring means for measuring the finished diameter of said pipe or tubes emerging from said apparatus. 25. An apparatus according to claim 24, wherein said sensing means takes the form of opposed pairs of rollers attached to the inner ends of radially arranged linear transducers, said rollers being urged into contact with said tubing or tubes by springs. . 26. An apparatus according to claim 24, wherein said detection means takes the form of a laser micrometer. 27. An apparatus according to claim 24, wherein said detection means takes the form of opposite pairs of proximity sensors, each said sensor measuring the free space between its reference face and the external surface of said pipe or tubes. . 28. An apparatus according to claim 1, wherein said rollers in said arrangement are all made with equal external diameters approximately 20 percent of that of said pipe or tubes to be treated. 29. An apparatus according to claim 1, in which said rollers in said arrangement are made in sets with equal external diameters in the range of 10 percent to 40 percent of that of said pipe or tubes to be treated. 30. An apparatus according to claim 1, wherein said bearing means are placed as close as possible to a plane passing through said contact areas of said rollers. An apparatus according to claim 1, wherein said bearing means is accommodated in a bearing housing of which an outer part is formed on the inner surface of a cylindrical extension formed in a radial mounting flange and a part Inside is formed on the outer surface of a radial network fixed to the external surface of said support cylinder. 32. An apparatus according to claim 31, wherein a pulley in the form of a cylindrical extension is formed around the outer circumference of said radial network. 33. An apparatus according to claim 32, wherein said pulley is removed and replaced by a gear adapted to drive said apparatus by means of a chain, or a gear adapted to drive said apparatus by means of gears. 34. An apparatus according to claim 1, wherein said rollers are provided at each end with short arrows, said arrows being rotatably supported on bearing means provided on said end flanges of said support cylinder, the axial lengths of said short arrows and said bearing means being made sufficiently long to accommodate the axial displacement caused by bias of said rollers. 35. An apparatus according to claim 1, wherein said rollers are each rotatably supported on individual yokes, each said yoke being pivotally mounted on an arrow passing radially outwardly through a bearing provided in said support cylinder, said yokes being displaced in a biased manner by force applied through bias rings joined pivotally to said yokes at their ends. 36. An apparatus according to claim 35, wherein the outer parts of said arrows of said yokes are screwed to link ball nuts, said ball nuts being driven by one or more stepper motors to radially move said yokes inward or outward. 37. An apparatus according to claim 1, wherein an index mark and complementary calibration marks are provided one of the ends of said end flanges and the other end of said support cylinder to facilitate the bias adjustment of said rollers. 38. An apparatus according to claim 1, wherein said rollers are provided with a centrally located, narrow convex part, to allow the application of a more localized force to said pipe or tubes. 39. An apparatus according to claim 1, wherein said rollers are provided with a concave portion centrally located to allow the application of a more dispersed force to said tubing or tubes. 40. An apparatus according to claim 1, wherein said support cylinder with its said roller array is fixed to said support means with quick release links and easily separated from said support means and replaced by another said support cylinder with its said roller arrangement adapted to treat pipe or pipes of a different diameter. 41. A method for reducing the diameter, rounding or straightening pipe or tubes by a rolling process comprising the following steps: (a) passing said pipe or tubes in continuous advance at a constant linear velocity through a plurality of rollers. parallel cylindrical, closely spaced and equidistant, long, narrow, arranged in a cylindrical arrangement parallel to the axis of said pipe or tubes maintained co-linear with that of said cylindrical roller arrangementsaid rollers being rotatably supported on supporting means and simultaneously capable of being biased to move their central contact areas radially inwardly; and (b) biasing said rollers to bring their central contact areas towards controlled forced contact with the external surface of said pipe or tubes; Y (c) rotating said cylindrical arrangement of said rollers at a controlled speed, thereby causing said central contact zones of said rollers to pass over and work in a laminated manner before the external surface of said pipe or tubes advancing continuously; and (d) detecting the linear velocity of said advancing pipe or tubes, the straightness of said pipe or tubes, the rotation speed of said cylindrical arrangement of said rollers and the finished diameter of said pipe or tubes; and (e) controlling said speed of rotation of said rollers in relation to the speed of advancement of said pipe or tubes; and (f) controlling the degree of bias of said rollers to regulate the finished diameter of said pipe or tubes. 42. A method according to claim 41, wherein said pipe or tubes are not internally supported by mandrels or the like during said rolling process. 43. A method according to claim 41, wherein the speed of rotation of said rollers is regulated to accommodate combinations of linear feed rate of said pipe or tubes and degrees of bias of said rollers. 44. A method according to claim 41, wherein said rolling process is applied to continuous lengths of said pipe or tubes or to discrete lengths of pipe or tubes. 45. A method according to claim 41, wherein said central contact zones of said rollers describe continuous, parallel, overlapping paths, in the form of a helix, along the external surface of said pipe or tubes and locally, they apply to the external surface of said pipe or tubes a compressive force in excess of the yielding force of their material, thereby causing said pipe or tubes to adopt a configuration with a smaller diameter. 46. A method according to claim 41, wherein the passage of said central contact areas of said rollers on the outer surface of said pipe or tubes corrects any lack of roundness of said pipe or tubes and causes its outer surface be polished. 47. A method according to claim 41, wherein said speed of rotation of said rollers, said height of said support means and said degree of bias of said rollers are detected by detection means. 48. A method according to claim 41, wherein said speed of rotation of said rollers, feed rate of said pipe or tubes, said height of said support means and said degree of bias of said rollers are controlled manually. 49. A method according to claim 41, wherein said speed of rotation of said rollers, said height of said support means and said degree of bias of said rollers are automatically controlled by control means accepting inputs of said detection means. 50. A method according to claim 41, wherein multiple units of said cylindrical arrangements of said rollers are used in tandem, said multiple units all rotating in the same direction or alternatively said units rotating in the opposite direction. 51. A method according to claim 41, wherein said rolling process is not limited by the diameter, wall thickness or length of said pipe or tubes. 52. A method according to claim 41, in which it produces in each step a greater reduction in the diameter of said pipe or tubes than that achieved by conventional methods. 53. A method according to claim 41, wherein the external surface of said pipe or tubes does not require lubrication during said rolling process. 54. A method according to claim 41, wherein it can be incorporated in a tube-forming mill to provide an immediate post-fabrication treatment of said pipe or tubes. 55. A method according to claim 41, wherein said cylindrical arrangement of said rollers is fixed to said support means with quick release attachment means and is easily separated from said support means and replaced by another said cylindrical arrangement of said rollers adapted to treat pipe or tubes of a different diameter. 56. A method according to claim 41, wherein the energy required to operate said rolling process is significantly less than that required in conventional rolling processes.