Claims:We claim:
1. A tube bending device for cold bending of tube in multi-dimension with bend to bend distance starts from 0.2 mm, the tube bending device comprising:
a bending former (01) having a radial bending profile (06);
a clamping die (08, 12);
an extending arm (20) on which the clamping die (08, 12) is mounted with a connecting plate (24), the mounted die (08, 12) fixedly engaged with bending former (01);
a hydraulic chuck (28) having a mandrel (27) to hold a straight tube (26), the straight tube (26) reaches to a predefined distance in the radial bending profile (06) of the bending former (01), the straight tube (26) is clamped with the clamping die (08, 12), and the extended arm (20) rotates to predefined position for first plane bending, and the tube 26) is rotated to another plane for bending.

2. The tube bending device as claimed in claim 1, wherein the bending former (01) comprises a top key way (02), a bottom keyway (03), a first mounting hole (04), a lifting hole (05), a radial bending profile (06) and a back support (07).

3. The tube bending device as claimed in claim 1, wherein the bending former (01) has centrally extended arm which has a top key way (02) and the radial bending profile (06).

4. The tube bending device as claimed in claim 1, wherein the clamping die (08, 12) are clockwise die (08) and anti-clockwise die (12).

5. The tube bending device as claimed in claim 1, wherein the clamping die (08, 12) has a mounting hole (09, 13), upper locking key (10, 14) and a tube holding profile (11, 15).

6. The tube bending device as claimed in claim 1, wherein diameter of the tube holding profile (11, 15) is equivalent to diameter of the radial bending profile (06) of the bending former (01).

7. The tube bending device as claimed in claim 1, wherein the extended arm (20) is supported by a base plate (16) and a vertical plate (17), wherein the extended arm (20) has a mounting hole (21) to mount the die (08, 12).

8. The tube bending device as claimed in claim 1, wherein the extended arm (20) rotates to bend the straight tube (26).

9. A method for manufacturing of cold bend tube in multi-dimension with minimum bend to bend distance for interconnection tubes, the method comprising:

inserting a straight tube (26) into bending former (01) upto bend distance with help of mandrel (27) of hydraulic chuck (28);
clamping the inserted straight tube with clamping die (08, 12);
rotating the inserted straight tube (26) to predefined position for first plane bending via extended arm (20);
releasing the clamping and rotating the tube (26) to another plane via the mandrel (27) of hydraulic chuck (28);
clamping again for bending another plane of the tube (26);
repeating the all steps N times to receive the predefined number of bends and number of planes.

10. The method as claimed in claim 9, wherein the clamping die (08, 12) is available separate for the clockwise bend and the anti clockwise bend, where the bending former (01) is common for both direction bends.
, Description:A BENDING METHODOLOGY TO COLD BEND TUBE MULTI-DIMENSIONALLY WITH MINIMUM BEND TO BEND DISTANCE FOR INTER CONNECTION TUBES IN BURNER PANLES OF STEAM GENERATORS
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to manufacturing multi-plane tube bends for burner panel used in high pressure high temperature steam generator. More particularly the present invention relates to designing of tube bending former for multi-dimensional cold bending of tube when bend to bend distance starting from as low as 0.2 mm. The present invention further relates to method of multi-dimensional bending of tubes to different radius of bend used in burner panels.
BACKGROUND AND PRIOR ART:
[002] In high pressure and high temperature steam generators used for power generation, evaporator panels are connected to burner panel at all the four corners. In constructing of the burner panel, there are 8 individual panels per corner per boiler are connected by multi plane bended tubes. In the manufacturing of the multi plane bend tubes from straight tubes, two bent half tubes are manually joined together by conventional Tungsten Inert Gas Welding (TIG) for required multi-dimensional bend since the bend to bend distance is only 0.2mm and the completed job is confirmed by the use of layout to ensure the correct multi plane angles. There after radiography test and local heat treatment (for welding stress relieving) for Manual TIG joints are to be performed. The radius of bend required are R 45, R 60 and R120 depending upon the shape of the burner panel. The loose bent tubes needs to have a bend to bend distance starting from as low as 0.2 mm as explained above. The burner panel consists of 412 such bends in 172 tubes. The outside diameters of the loose tubes in burner panel are 38.1mm. It is mandatory as per Indian boiler regulations, radiography of the manual TIG joints are to be radiographed if any flaw found repair the flaw which is time consuming and wastage of man power and material. Figure 1 shows one typical bend tube in multiplane. For better clarity view Q, R and S are given in Figure 1(A) for the said bend in Figure 1.
[003] US patent publication US20160023259a1 2016-01-28 with titled “Device for bending profile sections such as tubes”
The invention relates to a device for bending profile sections, comprising at least one bending form centred on a bending axis, provided with a peripheral groove that is interrupted by a cut-out, a stack of clamping jaw counterparts each comprising a cavity for clamping the profile section and having a shape designed to fit into the cut-out of each bending form with the cavity extending in the continuity of the peripheral groove of said bending form, means for the so-called vertical movement of the stack of clamping jaw counterparts which means are designed to move said stack along an axis parallel to the bending axis, a stack of clamping jaws, comprising cavities that complement the cavities of the clamping jaw counterparts, and means for the relative movement of the assembly made up of the bending form(s), the stack of clamping jaw counterparts and the stack of clamping jaws. This patent mentions about tube bending arrangement in single plane which is not relevant.
[004] Another US patent publication US9144835B2 dated 2015-09-29 and titled Tube and tube benders and methods of bending same. In a crossbow-style tube bender, a curved bending mandrel having a channel into which the tube in bent to form the bent tubing length has at least one relief surface forming a localized recess or depression in the surface of the channel. A forming bar or cross bar adapted to cooperate with a bending mandrel has on a first side of the forming bar a least one first pair of forming mandrels configured for a first tubing size, and on a second side of the forming bar has at least one second pair of forming mandrels configured for a second tubing size. The bender has a quick connect-disconnect mechanism permitting quick disconnection from and connection to the forming bar to utilize either the at least one first or at least one second pairs of forming mandrels. This patent mentions about tube bending arrangement in single plane which is not relevant.
[005] Japanese patent publication jp2016182615a dated 2016-10-20 and titled rotational bending method and rotational bending device. To suppress cracking of a bent outer side and decrease of a plate thickness in rotational bending. SOLUTION: A rotational bending method for bending a metal tube 1 by use of a bending metal mold, a wiper, a side booster, a back booster and a core grid, in which the core grid is moved without synchronization of a travel speed of the core grid with a travel speed of a neutral axis M of the metal tube 1 thereby suppressing local stretching of the metal tube 1 in the state that a specific part of the metal tube 1 on a bending outer side does not contact the core grid 2 for a long time, dispersing and averaging decrease of a plate thickness of the metal tube 1, and suppressing a remarkable decrease of the plate thickness such that said decrease occurs cracking on the bending outer side or does not satisfy an intended purpose of a finished article. This patent mentions about tube bending arrangement I to suppress cracking of bent outer side and decrease of plate thickness in single plane which is not relevant.
[006] US patent publication US9314830B2 dated 2016-04-19 titled Bending device. The bending device may comprise: a frame, center die, two sliding dies, and one or more motors. The center die may be positioned at a distal end portion of the frame and may advance towards a proximal end portion of the frame along a first path guide. The first sliding die may be positioned at a left portion of the frame and may advance towards and approximately near the first bent portion of the center die along a second path guide. The second sliding die may be positioned at a right portion of the frame and may advance towards and approximately near the second bent portion of the center die along a third path guide. The motors may actuate the movement of the center die, the first sliding die, and the second sliding die. This patent mentions about tube bending arrangement in single plane which is not relevant.
[007] Japanese patent publication JP5822285B2 dated 2015-11-24 and titled hot three-dimensional bending device. When a bending device (15) grasps the gripping point (24) of a metal tube (W) and moves along a specified movement path in three dimensional space while pulling the metal tube out from the guide rollers (12) in a three-dimensional hot bending device, a product of a specified shape can be obtained as a result of the metal tube (W), heated by a heating device (13), being subjected to a bending moment at the machining point (25) and after being bent, being cooled by a cooling device (14). Since it is not necessary for the guide rollers (12) to extrude the metal tube (W) and the bending device (15) has a metal tube (W)-pulling function, the need for coordinated control of a metal tube (W)-feeding device with the bending device (15) is eliminated. Not only is product machining precision increased but limitation of the length of the product by the capacity of the metal tube (W)-feeding device is eliminated and it is possible to machine long products proportional to the amount of the metal tube (W) pulled out by the bending device (15). This patent mentions about Hot tube bending arrangement which is not relevant.
[008] The above method of manufacturing multi plane bend tubes is time consuming, more man power and expensive since TIG welding is involved. Hence there is a need to find out an alternate method to avoid welding for such a multi plane bend where bend to bend straight distance available is as low as 0.2mm.
OBJECTS OF THE INVENTION:
[009] The principal objective of the present invention is to provide tube bending former for multi-dimensional cold bending of tube with bend to bend distance starting from as low as 0.2 mm eliminating involvement of welding.
[0010] Another object of the present subject matter is to provide a multi-dimensional bending method of bending tubes with size 38.1 mm outside diameter for radius of bend R 45, R60 and R 120 where R is the radius of the bend and the number indicates the dimensions in mm.
[0011] Another object of the present subject matter is to provide cold bend tubes in multi-dimensional plane without heating the tubes.

SUMMARY OF THE INVENTION:
[0012] The subject matter disclosed herein relates to a bending formers and clamping dies with extension arm, designed and manufactured for tube bending machine to cold bend the straight tube at multi-dimensional angle with minimum bend to bend distance, to produce multi-dimensionally bended tube of outside diameter 38.1 mm irrespective of tube thickness with radius of bend R45, R60 and R120. Manufacturing of multi-dimensionally bended tube without joining two pre bended tubes. Bending of straight tube with marked bending line is done with a pre-positioned bending former and clamping die with extension arm in tube bending machine to produce multi-dimensional bend. The bending is controlled with the bending parameters fed into the machine to produce smooth bend and the multi-dimensional angle of bend is controlled by the rotation of machine hydraulic collet. Specially machined bending former with integral features, clamping die and extended arm which are connected to the tube bending machine. The hydraulic chuck with mandrel inserted into the tube which is to be bend and travels to the required distance in the bending former and clamped with clamping die whereas the extended arm rotates to the required position for first plane bending and the clamping is released to rotate the work piece to the another plane and clamped again for bending in the another plane. And the operation is continued depending upon the number of bends and number of planes required. The clamping die is available separately for clock-wise bend and anti-clockwise bend whereas the bending former is common for both direction of bending. Thus , with as low as 0.2 mm bend to bend distance multi-plane bending carried out for any radius of the bend and saving man power, material and cost.
[0013] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] 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, the left-most digit(s) of 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 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:
[0015] Fig. 1 illustrates isometric view of the one of the bended tube in multi-dimensional angle with minimum bend to bend distance;
[0016] Fig. 1 (A) illustrates Front, Top, and Side view of the bended tube shown in figure 1;
[0017] Fig. 2 illustrates structure of designed bending former, in accordance with an embodiment of the present subject;
[0018] Fig. 3 illustrates structure of clockwise clamping die, in accordance with an embodiment of the present subject;
[0019] Fig. 4 illustrates structure of anti-clockwise clamping die, in accordance with an embodiment of the present subject;
[0020] Fig 5 illustrates structure of extension arm, in accordance with an embodiment of the present subject;
[0021] Fig. 6 illustrates clamping die either clockwise or anti-clockwise and bending Former arrangement in bending machine, in accordance with an embodiment of the present subject; and
[0022] Fig. 7 illustrates bending arrangement used in bending the tube with present bending former and die, in accordance with an embodiment of the present subject.
[0023] 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.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0024] The subject matter disclosed herein relates to a bending formers and clamping dies with extension arm, designed and manufactured for tube bending machine to cold bend the straight tube at multi-dimensional angle with minimum bend to bend distance, to produce multi-dimensionally bended tube of outside diameter 38.1 mm irrespective of tube thickness with radius of bend R45, R60 and R120. Manufacturing of multi-dimensionally bended tube without joining two pre bended tubes. Bending of straight tube with marked bending line is done with a pre-positioned bending former and clamping die with extension arm in tube bending machine to produce multi-dimensional bend. The bending is controlled with the bending parameters fed into the machine to produce smooth bend and the multi-dimensional angle of bend is controlled by the rotation of machine hydraulic collet. Specially machined bending former with integral features, clamping die and extended arm which are connected to the tube bending machine. The hydraulic chuck with mandrel inserted into the tube which is to be bend and travels to the required distance in the bending former and clamped with clamping die whereas the extended arm rotates to the required position for first plane bending and the clamping is released to rotate the work piece to the another plane and clamped again for bending in the another plane. And the operation is continued depending upon the number of bends and number of planes required. The clamping die is available separately for clock-wise bend and anti-clockwise bend whereas the bending former is common for both direction of bending. Thus , with as low as 0.2 mm bend to bend distance multi-plane bending carried out for any radius of the bend and saving man power, material and cost.
[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 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.
[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.
[0027] Fig. 2 illustrates structure of designed bending former, in accordance with an embodiment of the present subject. The bending former 01 is prepared in a single 140mm thickness plate. The bending former 01 has diameter about 300mm. The bending former 01 has vertically extended portion from the middle to define the locking and bending profile. The bending former 01 has a top key way 02, a bottom keyway 03, a first mounting hole 04, a lifting hole 05, a radial bending profile 06 and a back support 07. The top key way 02 is a horizontal slit cut to receive a vertical part of a die. The bottom key way 03 is also a horizontal rectangular slit cut on circular base plate 01 along diameter of the bending former 01. The vertical extended portion is in middle of the bending former 01. The top key way 02 and the bottom key way 03 are in same angle and in same direction in reference to the base circular plate of the bending former 01. The first mounting hole 04 is used to mount the bending former 01 on a lifting machine (which is not shown in the figure). A person skilled in the art is well aware about the lifting machine in the bending of tubes. The lifting hole 05 works in tandem with the lifting machine to lift the bending former 01. The bending former is lifted with the help of the lifting hole 05. On the vertical extending profile has a radial bending profile 06 which is semi circular. Further, the diameter of the radial bending profile 06 matches with the diameter of straight tubes which are to be bent. Therefore, the bending former 01 can be changed for changing the diameter of the straight tubes. Accordingly, the bending former 01 of the bending machine can be changed based on the diameter of the straight tube which is easy and fast due to mounting with fasteners on the mounting holes. The radial bending profile 06 is below the top key way 02. The top key way 2 is provided at the upper surface of the vertical extending profile. The top key way 02 and the bottom key way 03 are used to fix the bending former 01 with an extending arm, which is explained in detail in figure 5 and 6. The bottom key way 03 has more width are compared to the top key way 02.
[0028] Fig. 3 illustrates structure of clockwise clamping die, in accordance with an embodiment of the present subject. The clockwise clamping die 08 is prepared by high thickness plate. The clockwise clamping die 08 has a mounting hole 09, first upper locking key 10, and a tube holding profile 11. The first upper locking key 10 engages with the top key way 02 to fix the position and restrict rotation of the die in tandem with the straight tube. The lower portion of the clockwise clamping die 08 engages with the bottom key way 03. By the engagement of the first upper locking key 10 and lower portion of the clockwise clamping die 08 with the top key way 02 and the bottom key way 03, respectively fixes the die with the bending former 01. The tube holding profile 11 matches with the radial bending profile 06 of the bending former 01. The diameter of the tube holding profile 11 depends on the diameter of the bending former 01. The mounting hole 09 mounts the clockwise clamping die 08 on extending profile as shown in figure 5 and figure 6.
[0029] Fig. 5 illustrates structure of anti-clockwise clamping die, in accordance with an embodiment of the present subject. The anti-clockwise clamping die 12 is made of high thickness plate. The anti-clockwise clamping die 12 has a mounting hole 13, upper locking key 14, and a tube holding profile 15. The anti-clockwise clamping die is connected with the extending arm as shown in figure 5 and 6 at one end and other end which has locking key and tube holding profile is engaged with the bending former. The upper locking key 14 engages with the top key way 02 to fix the position and restrict rotation of the die in tandem with the straight tube. The lower portion of the anti-clockwise clamping die 12 engages with the bottom key way 03. By the engagement of the upper locking key 14 and lower portion of the clockwise clamping die 12 with the top key way 02 and the bottom key way 03, respectively, fixes the anti-clockwise die 12 with the bending former 01. The tube holding profile 15 matches with the radial bending profile 06 of the bending former 01. The diameter of the tube holding profile 15 depends on the diameter of the bending former 01. The mounting hole 13 mounts the anti clockwise clamping die 12 on extending profile as shown in figure 5 and figure 6.
[0030] Fig 5 illustrates structure of extended arm, in accordance with an embodiment of the present subject. The extended arm or sub assembly is made of heavy metal plates. The sub assembly has an extended arm. The sub assembly is made by fillet welding 22. The sub assembly has a base plate 16, a vertical plate 17, and extended arm 20. The base plate is machined with key 19 at the bottom and drilled with mounting hole 18. The sub assembly is positioned on bending machine with the help of the key 19. The key 19 of the sub assembly engages with the bending machine for movement of the bending former 01. The extended arm 20 is supported by the base plate 16 and the vertical plate 17. The extended arm 20 is drilled with a hole 21 at the end of the extended arm at the top. The hole 21 is used to mount the clamping die with the extended arm 20. As shown in figure 3, and 4, the mounting hole 09 and 13 of the dies 08, 12 fixes with the hole 21 of the extended arm 20 with fasteners to fix the die.
[0031] Fig. 6 illustrates clamping die either clockwise or anti-clockwise and bending Former arrangement in bending machine, in accordance with an embodiment of the present subject. The bending former 01 is connected with the either of the clamping die 8 or 12 by placing a connecting plate 24 at the top and fastened with bolts and nuts 23. In turn the clamping die having upper locking key 10 inserted into the top key way 02 and the bottom width of the clamping die which enter into the bottom keyway 03 of the bending former 01 to ensure the proper positioning and strength to clamping die during bending. Once the die is fixed with the extended arm 20 of the sub assembly, the die 8 or 12 engages with the bending former 01 for bending the straight tubes.
[0032] Fig. 7 illustrates bending arrangement used in bending the tube with present bending former and die, in accordance with an embodiment of the present subject. Figure 7 shows a hydraulic chuck 28 of the bending machine (which is not shown in the figures) having a mandrel 27 to hold a work piece which is straight tube 26. The straight tube 26 travels to reach the radial bending profile 06 of the bending former 01 which is taken to ending machine bed through lifting hole 05 and is mounted on the machine bed (not shown) through mounting hole 04 by using former bolts 25. The bending former 01 gets locked with anti-clockwise clamping die 12. The extended arm 20 is positioned using the bottom key 19 inserted in the key way of the machine bending arm (which is not shown in the figures) and is then tightened to the bending machine arm (not shown) by means of fasteners through plurality of mounting hole 18 present on the sub assembly as shown in figure 5.
[0033] The hydraulic chuck 28 with the mandrel 27 inserted into the tube 26 which is to be bend and travels to the required distance in the bending former 01 and clamped with clamping die 08 or 12 whereas the extended arm 20 rotates to the required position for first plane bending and the clamping is released to rotate the work piece to the another plane and clamped again for bending in the another plane. And the operation is continued depending upon the number of bends and number of planes required. The clamping die is available separately for clock-wise bend and anti-clockwise bend whereas the bending former is common for both direction of bending.
[0034] Once all the arrangement is completed, the bending machine arm 27 rotates in the anti-clockwise direction depending upon the degree of bend required in one plane and the anti-clockwise clamping die 12 retards back after stage 1 bending and the one plane bended work piece, i.e., straight tube 26 is rotated according to the required another plane and angle and is locked again by anti-clockwise clamping die 12. Now, the bending machine arm is rotated to the desired position. The bending activity said above is repeated in the same fashion depending upon the number of bends required in the same work piece (26). The same operation is repeated for clockwise bending tubes with the use clock-wise clamping die 08. Thus, the multi plane bending of the tubes is carried out without involving welding and without the constraint of bend to bend distance.
[0035] Further, the present subject matter explains a method for manufacturing of cold bend tube in multi-dimension with minimum bend to bend distance for interconnection tubes. In the present method inserting a straight tube 26 into bending former 01 upto bend distance with help of mandrel 27 of hydraulic chuck 28. Clamping the inserted straight tube with clamping die 08, 12 and rotating the inserted straight tube 26 to predefined position for first plane bending via extended arm 20. Once one plane is bent, releasing the clamped tube and rotating the tube 26 to another plane via the mandrel 27 of hydraulic chuck 28 rotation. After rotation, clamping again the tube 26 for bending another plane of the tube 26 and repeating the all above steps N times to receive the predefined number of bends and number of planes.
[0036] The present subject matter relates to bending formers and clamping dies with extension arm, designed and manufactured for tube bending machine to cold bend the straight tube at multi-dimensional angle with minimum bend to bend distance, to produce multi-dimensionally bended tube of outside diameter 38.1 mm irrespective of tube thickness with radius of bend R45, R60 and R120. Manufacturing of multi-dimensionally bended tube without joining two pre bended tubes. Bending of straight tube with marked bending line is done with a pre-positioned bending former and clamping die with extension arm in tube bending machine to produce multi-dimensional bend. The bending is controlled with the bending parameters fed into the machine to produce smooth bend and the multi-dimensional angle of bend is controlled by the rotation of machine hydraulic collet. Specially machined bending former with integral features, clamping die and extended arm which are connected to the tube bending machine. The hydraulic chuck with mandrel inserted into the tube which is to be bend and travels to the required distance in the bending former and clamped with clamping die whereas the extended arm rotates to the required position for first plane bending and the clamping is released to rotate the work piece to the another plane and clamped again for bending in the another plane. And the operation is continued depending upon the number of bends and number of planes required. The clamping die is available separately for clock-wise bend and anti-clockwise bend whereas the bending former is common for both direction of bending. Thus , with as low as 0.2 mm bend to bend distance multi-plane bending carried out for any radius of the bend and saving man power, material and cost.
[0037] 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.