Claims:WE CLAIM:
1. An apparatus (100) for correcting ovality in Pipes comprising:
a Bottom Plate 1 to which four rollers are attached for free movement;
Two Front Rollers 2 can rotate about the vertical axis enabling the whole apparatus to turn and move in all the direction on the floor;
Two Rear Rollers 3 are fixed rigidly to the Bottom Plate 1 enabling front and back movement;
A height adjustable Stand 4 welded to the center of the Bottom plate 1;
Two Pillow Block Bearings 7 fastened to a Top Plate 5 which a stepped balancing Rod 6;
One end of the Rod 6 is hard fastened with a C-Clamp 8 to hold a hydraulic Jack 14;
The other end of the Rod 6 is hard fastened to a Counter Weight Block 9 fixed at right angle to the axis of the hydraulic Jack 14;
Characterized in that the Rod 6 contains a Locking Disk 10 that can be locked tightly to a Locking Plate 11 on the Top Plate 5, to arrest the hydraulic Jack 14 at any axis inside a Pipe 17.

2. The apparatus as claimed in claim 1, wherein the weight of the apparatus (100) is supported and balanced evenly with a help of a Thrust bearing 12 fixed at the main stem of the stand (4).

3. The apparatus as claimed in claim 1, wherein the apparatus (100) can be moved from one place to another with the aid of a handle 13 fixed to the Bottom Plate 1.

4. The method of correcting ovality, comprising the steps of:
Measuring the diametrical ovality in different axis at the free end of the pipe and finding the ovality correction axis, which is at right angles to the maximum ovality axis;
Choosing the correct capacity and size of hydraulic jack according to the listed table, and suitably providing correct size C-clamps, top and bottom profile plates, and counter weight blocks;
Placing the hydraulic jack along the axis of ovality correction, and locking its position with the help of locking disk and locking plate arrangement fixed in the rod;
Resting first the base profile plate fitted at the bottom of the hydraulic jack, on the inside diameter of the pipe by using hand rods fitted in the height adjustable stand;
Pressurizing the hydraulic jack, to extend the ram fitted with the top profile plate to make contact with the inside diameter of the pipe;
Expanding the ovality correction axis of the pipe by cold working beyond its elastic limit using the pressurized ram of the hydraulic jack;
Repeating the above-mentioned procedure at any axis of the pipe till the roundness of the pipe comes under fabrication tolerance; and
Depressurizing the jack and retrieving outside the apparatus from inside of the pipe using the handle.
, Description:A DEVICE AND METHOD FOR MULTI-AXIS OVALITY CORRECTION IN PIPES
FIELD OF INVENTION
[001] The invention relates to a device and method for correcting ovality (out of roundness) about any axis of pipes and in particular for correcting ovality in pipes used in Boiler Piping.

BACKGROUND OF THE INVENTION

[002] Power Plants contain Critical piping lines, which carry steam and water at high pressure and temperature. High Alloy Steels that are selected for such piping have to be fabricated with close tolerances without compromising quality. During pipe fabrication, Straight Pipes or Straight Pipes after getting formed into Bends, are subjected to Post Forming Heat Treatment (Normalizing and Tempering) or Post Weld Heat Treatment (Stress Relieving). After heat treatment, pipes with diameter to thickness ratio greater than 15, becomes oval and loses its roundness at the free ends. Also, localised dents can be created on the surface of the pipe due to improper loading or mishandling. These dents can affect the aesthetic appearance of the pipe.

[003] The free end of the pipe should be free from ovality. This ensures a correct edge preparation without affecting the design requirement and also a correct fit with the adjacent pipe to which it is to be welded. Steel Pipes used in Boiler Piping layout are laid after being joined to each other by peripheral welding at the laying site. While welding, the groove faces formed in the pipe end portions must be butted against each other with high accuracy. If the butting accuracy is inadequate, peripheral welding quality may be degraded and efficiency may be lowered due to the increase in man-hours for correction and, in the worst case, the pipes cannot be joined to each other. In order to increase the butting accuracy of groove faces, the roundness in the pipe end portion must be improved, and tight roundness specifications are imposed for improving the quality of the pipes.

[004] The roundness of a pipe can be improved by expanding the pipe by means of cold working at local portions beyond its elastic limit. The principal objective of the pipe expanding process is to correct the difference between the longitudinal diameter and the transverse diameter of the metal pipe. In order to improve the roundness, a portion where the shape is difficult to secure, must be corrected locally.

[005] EP 2538000 A2 to Oellgaard Boerge, et al teaches about an invention, which relates to tooling and a method of using the tooling to deform a flange of a wind turbine tower section to correct any ovality that might otherwise prevent fasteners from passing through apertures of adjacent flanges.

[006] US 3353391 A to Russel W Anthony, teaches about an invention, which relates to a method and apparatus for reducing nicks and burrs and for correcting ovality in heat treated internal gears by moving a pair of hardened pinions in mesh at diametrically opposite points with the gear apart to apply sufficient pressure to distort the internal gear beyond its elastic limit.

[007] US 8544311 B2 to Makoto Abe, et al teaches about an invention, which relates to a pipe end shape correcting apparatus capable of improving the roundness without loss of work efficiency and the mechanical damage to a weld bead even in the case where the pipe ends of UOE metal pipes having various outside diameters are worked.

[008] The technical solutions provided in the known arts are not adequate in providing a clear method and/or apparatus that can be used or applied to correct ovality and local dents in pipes during the process of fabrication. There are references to ovality correction in tubes, gears and flanges of wind turbine which cannot be used in the current field of invention.
[009] The problem of ovality in pipes requires a sturdy, movable, safe and multipurpose arrangement, which can deform the pipes by cold working. To reduce ovality at any axis of the pipe is also to be addressed with minimum man power requirement for handling the arrangement. The method of working on the pipes using the arrangement has to be detailed making the operation and process safe, as the cold working on a high alloy steel pipes will require pressure in range of 100 to 500 tons.

OBJECTS OF THE INVENTION

[0010] It is an object of the present invention to propose a device and method for multi-axis ovality correction in pipes.

[0011] Other object of the present invention is to propose a device and method for multi-axis ovality correction in pipes and localize dent at any axis of the free ends or near free ends of pipes used in Boiler Piping, more specifically to pipes with D/t >15 where D is the outside diameter in mm and t is the thickness in mm.

[0012] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes that can be moved from one place to another in the shop floor along with a provision to place and hold the cold working device namely a hydraulic jack at any axis of the pipe and also at the required height from the floor.

[0013] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes wherein the forces from the hydraulic jack are applied to the inner surfaces of the pipes and are directed radially outward.

[0014] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes wherein the points of application of outward force to the pipes are substantially 180 degrees apart with reference to the centre axis of the pipe.
[0015] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes wherein during the application of outward force to the pipes the entire setup is balanced and stays rigid in a safe position.

[0016] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes wherein the outward force applied using the hydraulic jack is transmitted to the inner diameter of the pipe through rigidly fixed profile plates on both top and bottom of the hydraulic jack.

[0017] Yet another objective of the invention is to propose a device for multi-axis ovality correction in pipes wherein the reaction to the outward force applied using the hydraulic jack is transmitted to the floor through the thrust bearing fixed at the main stem of the device.

[0018] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taken into consideration with accompanying drawings in which preferred embodiments of the present subject matter are illustrated.

SUMMARY OF THE INVENTION

[0019] The problem of ovality in pipes is solved using a special fixture arrangement in combination with a hydraulic jack, which can give a direct action by means of cold working on the pipe’s inner diameter at any required axis. The hydraulic jack is fixed to a height adjustable, movable trolley by means of C- Clamps to a stepped rod mounted on two pillow block bearings at the flat top of the trolley. One end of the rod carries a counter weight block to balance the weight of the hydraulic jack mounted on the other end. The components on the apparatus namely the rod, C-Clamp, pillow block bearing and counter weight block can be changed depending on the size of the pipe and capacity of the hydraulic jack required for ovality correction.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0020] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
Fig. 1 is an outline diagram of an embodiment of the device according to the invention in Isometric view.
Fig. 2 schematically show the front view of mounting profile plates and positioning the hydraulic Jack inside the pipe.
Fig. 3 schematically shows an example of ovality correction in Pipes using the device

[0021] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0022] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0023] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.

[0024] The present subject matter relates to a process to recover clean coal with less ash content from high ash coal fines using gravity concentration.

[0025] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

[0026] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope. The present invention will now be described more specifically with reference to the following specification.

[0027] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

[0028] Pipes with D/t >15 (where D is the outside diameter in mm and t is thickness in mm) have a tendency to deform at the free ends during fabrication. Straight Pipes when stored or handled improperly loses its roundness at multiple axis. Repeated heat treatment in straight pipes and bend pipes distorts the ends. Improper loading and storing of pipes can also create localized dents on the surface of the pipes. The unshaped ends create quality problems for carrying out further operations like edge preparation, attachment fit-up and butt welding during pipes fabrication. The requirements for solving the above technical problem with a number of constraints have been overcome by this invention. The device construction and the working methodology are discussed below.

[0029] Fig. 1 shows the isometric view of the device in which the whole setup stands on a Bottom Plate 1 to which four rollers are attached for free movement. Two Front Rollers 2 can rotate about the vertical axis enabling the whole device to turn and move in all the direction on the floor. Two Rear Rollers 3 are fixed rigidly to the Bottom Plate 1 enabling front and back movement. A height adjustable Stand 4 is welded, by shielded metal arc welding (SMAW) but is not limited to it, to the center of the Bottom plate 1, which on manual rotation of a set of hand rods (20) adjusts the height of the device up and down to the required height of working. Two Pillow Block Bearings7 which are fastened to a Top Plate 5 which carries a stepped balancing Rod 6. The two ends of the Rod 6 are square threaded. One end of the Rod 6 is hard fastened, using SMAW process, with C-Clamp 8 to hold a hydraulic Jack 14 (not shown in the figure). The C-Clamp 8 has two eyes on either sides, through which M20 bolt (2 sets) and nut is used and hand fastened and tightened for holding the Jack 14. The special C-Clamp 8 gives maximum contact area to carry the heavy weight (100-400 kg) hydraulic Jack 14 firmly. The other end of the Rod 6 is welded to a Counter Weight Block 9 using SMAW process. The Counter Weight Block 9 fixed at right angle to the axis of the hydraulic Jack 14. The Weight of the counter weight block 9 depends on the weight of the jack 14 used on the other side. It ranges from 200 Kg to 300 Kg.

[0030] To arrest the hydraulic Jack 14 at any axis inside a Pipe 17 (whose ovality correction is needed), the Rod 6 contains a Locking Disk 10 that can be locked tightly to a Locking Plate 11 on the Top Plate 5. The Locking Disk 10 has holes pitched at every 30 degree from the center of the disk. Using a Lock Nut in the Locking Disk 10 and Locking Plate 11 arrangement, the Rod 6 is arrested at the required angle for ovality correction. The device weight is supported and balanced evenly with a help of a Thrust bearing 12 fixed at the main stem of the trolley. The entire device can be moved from one place to another with the aid of a handle 13 fixed using SMAW process to the Bottom Plate 1.

[0031] Fig. 2 shows the front view of hydraulic jack placed inside the pipe 17 for ovality correction. The key point during ovality correction is finding the axis of ovality or the axis where maximum distortion has happened. The hydraulic Jack 14 is placed exactly at right angles to the axis of ovality. The Ram of hydraulic Jack 14 makes contact with the inner diameter of the Pipe 17 through a Top Profile Plate 15 and the bottom of the Jack through a Bottom Profile Plate 16. The Profile Plates 15 and 16, can be changed according to the size of the hydraulic Jack 14.

[0032] Fig. 3 show the entire working device with a view of jack placement inside the pipe. Preliminary precautions that are to be ensured before operation of the device are as follows: The Jack 14 and the Block 9 to be kept fixed in still position by securing the Locking Plate 11, all the bolts and nuts are to be tightened firmly, the profile plates 15, 16 are to be tight fitted with the hydraulic Jack 14, the trolley to be placed in a flat surface with the Pipe 17 face opposite to each other, the pipe should be placed flat on the floor with proper wooden packing at the bottom. Proper personal protective equipment to be worn by the worker employed.

[0033] Initially, the pipe is placed in a well-balanced position on the floor. It is then checked for diametrical ovality at its ends in at least four different axes. The maximum ovality axis has to be decided and the ovality correction axis should be marked at right angles on the pipe. The device is the then brought closer to the pipe and positioned using handle 13. The hydraulic Jack 14 is then rotated and made parallel to the ovality correction axis. The Bottom Profile Plate 16 is made to rest on the inner surface of the pipe on one end of the ovality correction axis. The height is adjusted accordingly by rotating the hand rod (20) in Stand 4. The Locking Disk 10 and the Locking Plate 11 are locked in position using a Lock Nut. The hydraulic Jack 14 is then pressurized and the cylinder ram along with the Top Profile Plate 15 makes contact with the other end of the ovality correction axis of the pipe. Meanwhile, the whole device gets aligned automatically as the Rollers 2, 3 are free moving. The hydraulic pressure is further increased to cold work on the pipe to bring back the roundness within fabrication limits. The whole process is repeated in different axes until near roundness is achieved as per the quality standards followed. After de-pressurizing the hydraulic jack 14, the whole setup is then retrieved backwards.

[0034] The same procedure is flowed for dent correction in pipes. Surface dents are primarily visually identified. The size of the dent namely the length and depth are first measured using a straight edge and a measuring tape. The same device can be used for correcting dents at the near ends of the pipes. The length of the Rod 6 determines the extent up to which the Jack can be inserted inside the pipe. To balance the whole device, counter weight blocks are suitable chosen. The hydraulic jack is positioned at the dent location and pressurized to correct localized dents at any axis.

[0035] Although embodiments for the present subject matter have been described in language specific to package features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/device of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

[0036] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

[0037] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

[0038] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.