Claims:WE CLAIM:
1. A device (10) to ensurecenter alignment of tubes to be welded autogenously from internal diametercomprising of
A custom designed plate (2) for aligning said tubes;
A small plate (3) moving in linear direction and perpendicular to said custom designed plate (2);
Fastening means to fasten said small plate (3) to said custom designed plate (2) perpendicularly; and
Measuring scale (7) engraved on said custom designed plate (2) for measurement.

2. The device (10) as claimed in claim 1 wherein said small plate (3) is also custom designed with a small sharp edge measuring to the displacement on the scale.

3. The device (10) as claimed in claim 1, wherein the components of said device (10) are moved in perpendicular direction so that the zero reference of measurement will be held as the difference between the outer diameter sizes of the circular section of Internal TIG welding system and measuring tube.
, Description:FIELD OF THE INVENTION
[001] The present invention generally relates to a device for alignment of the tubes. The present invention in particular relates to a device to ensure center alignment of the tubes to be welded autogenously from internal diameter.
BACKGROUND OF THE INVENTION
[002] Header to stub welding is one of the important sub process in boiler manufacturing and requires structural integrity. At present, after edge preparation, the joints are welded using different processes but there are instances where the penetration is not complete. This is one of the reasons where the structural integrity of weld gets affected and leakages are also reported. There exists no uniformity in the occurrence of this defect and hence it is not possible to be corrected using parameter selection.
[003] As an alternate solution to ensure root fusion, it was proposed to fuse the root internally using autogenous TIG process. This will ensure complete penetration so that the combination of both internal and external welding of the stubs will give good quality weld joints. Different design configurations are considered for implementation with and ID range of 25 mm till 60 mm. The height of the stubs range from 100 mm till 235 mm. However, during implementation it was found that the alignment of the torch inside the stub cannot be referenced visually or otherwise. This will seriously impact the fusion of the joints as the weld is autogenous and the penetration will be affected if the alignment is different. The typical stub dimensions used in supercritical boilers is used for implementation with different materials used in headers and their characteristics (in terms of process, consumables, preheating temperatures, edge preparation style, thickness, ID and OD combinations, stub height) were considered for implementation. Hence, to ensure that the torch is aligned centrally inside the stub, this instrumental arrangement is proposed in the present invention.

[004] EP0420663 B2 describes an invention directed to a surveying process and apparatus for carrying out the process. In particular the inspection process is directed to taking alignment measurements of a rotary kiln, including use of the method with a hot, operating kiln.

[005] US5148238 A describes another invention related to kiln and is used to identify the location of the rotational center line of a long, cylindrical body having a number of support bearings spaced along its length, is determined during the rotation of the body.

[006] CN104330077 A provides a method relating to a combined measuring method based on a two-point center-alignment model and belongs to the technical field of engineering measurement. By means of the two-point center alignment coordinate system transfer model, coordinate systems of the laser tracker and the gyro theodolite are integrated so that the true north orientation of the model launching vehicle is directly measured and obtained under the coordinate system of the laser tracker.

[007] US7446328 B2 provides a combination of medical and engineering requirements of measurement of different positioning requirements that includes multiple external measurements. The alignment system includes multiple external measurement devices which obtain position measurements of components of the radiation therapy system which are movable and/or are subject to flex or other positional variations.

[008] CN103170904 A describes an invention he invention discloses a cylinder hole center alignment device of a honing machine. The cylinder hole center alignment device of the honing machine comprises an extended rod which is fixed with a honing head clamping handle on the same shaft. A columned measuring head is fixed at the free end head of the extended rod, and the columned measuring head and the free end head are on the same shaft. A gap which penetrates along the diameter of circumference of the measuring head to a side wall of the other side of the measuring head is formed in a side wall of one side of the measuring head. A plurality of through holes which penetrate through the gap to the side wall of the other side of the measuring head are formed in the position of the gap on the side wall of the measuring head. A screw hole which is vertical to the gap is formed in the side wall of the measuring head. Connecting rods of leveraged tables penetrate through the through holes and are fixed in the through holes through bolts in fastening screw holes. According to the cylinder hole center alignment device of the honing machine, the connecting rods of leveraged tables penetrate through the through holes to enable the measuring head at the position of the gap to clamp up and down through the bolts in the fastening screw holes, and thus the connecting rods are fixed in the through holes, and the fact that the leveraged tables and extended rod are fixed together in rigidity. Direct alignment of cylinder holecenter can be completed quickly and is more accurate than indirect positioning. However, these cannot be used for welding of tubes as they provide no access or provision for executing this principle of working.

[009] There are also alignment gauges that could be used for automotive applications. Patents relating to US2586194 A, US1564654 A, US2664643 A, US3057074 A, EP0085253 A1, and US4574489 A are some examples of IPRs which relate to alignment requirements but all take into consideration of external reference or alignment. The requirement to address internal alignment is left unaddressed.

[0010] To summarize the prior art, the inventions pertaining to the measuring instruments or devices are highly specific in nature and there exists no direct or indirect measurement device which can consider measurement of deviation in internal alignment of welded tubes.

[0011] It is asserted that there exists no similar patent or published article in the area of measuring devices which can deal with the requirement of ensuring internal alignment of welded tubes with the welding machine.

[0012] Hence, to ensure that the torch is aligned centrally inside the stub, the present invention is presented.
OBJECTS OF THE INVENTION
[0013] It is therefore an object of the invention to design and develop a device to ensure position, alignment of the Internal welding machine with the centerline of the stubs to maintain uniform weld penetration on root side of the stub.

[0014] Another object of the present invention is to design and develop a device to ensure root fusion, through fusing the root internally using autogenous TIG process.

SUMMARY OF THE INVENTION

[0015] The invention will cater to the requirements of ensuring alignment of tubes during internal welding. The device according to the present invention will help the operator to ensure alignment without having access to the internal part of the stubs. Presently, the alignment is presumed and not verified by any measurement or device. Since root penetration and integrity are of topmost priority, this device will help us to ensure the alignment by means of measurement. The device is easy to scale and is flexible in design to suit difference geometrical sizes of the jobs.
BRIEF DESCRIPTIONS OF THE ACCOMPANYING DRAWINGS
[0016] Figure 1 shows the description of arrangement of different components involved in the invention.

DETAIL DESCRIPTION OF THE INVENTION
[0017] The present invention will be described in detail below with reference to an embodiment as shown in the drawing.

[0018] The present invention relates a device which measures the deviation of the alignment of the welded stubs with the internal TIG welding machine. The principle is to be ensuring alignment externally between two tubes by providing arrangements in such a way that any deviation will be the measure of deviation from the center line of the alignment.

[0019] The internal TIG welding machine is mounted to the stub to be welded using a mandrel which holds on the stub with its internal diameter. This is the working part of the machine and is indicated as 1 in the Figure.

[0020] The measuring part of the system consists of two plates differentiated as 2 and 3 in the diagram. The plates are to be customized to match the contour of the header to stub joints. Hence, they are made suitable to match the outer diameter, header profile in a generic fasion. The plates (2 & 3) are custom designed to suit the measurement requirements and the arrangement consisting of both 2 and 3 can be moved independently of the system along the x axis. The bigger plate (2) consists of a section which is engraved with a scale, a hole for fastening the plate with the other using fastening means such as nut and bolt, and a couple of positioning grooves for holding the smaller plates in perpendicularity. This will be placed in contact with the TIG welding machine so that it is held firmly along the side wall (4) and acts as a reference against with the tube position is to be aligned. (3) Represents the movable arm of the measuring device whose movement can be referred against the scale (7). If both the surfaces of (2) and (3) of the contact match, then the alignment is accurate for the welding torch to rotate inside the stub. If there exists any difference, then the difference in alignment is equal to the value stated in the measuring scale (7) from the reference value. The movable arm (3) is aligned perpendicular to larger plate (2) using a guideline (5) and is positioned using nut and bolt mechanism using the provision (6) in the smaller scale.

[0021] The advantage is ease of operation, ability to address any structural types for checking alignment and quicker measuring time.