Claims:1. An arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process comprising straight tube butt 5 welding machine (15) for welding tubes (1), wherein the welding machine (15) is having a plurality of welding torches (3) loaded with respective filler wire (17), wherein a gas mixture unit (5) is provided for supplying mixed gas of Argon and Carbon dioxide to the selected torch for the welding of 10 tubes, wherein a plurality of Argon cylinders (10) are provided and outlet of each of the cylinders (10) is connected to a header (9) in flow communication with the mixture unit (5), which is provided in connection with a carbon dioxide cylinder (12).
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2. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1, wherein the two tubes (1) to be welded are clamped in chuck (2) at left hand side and right hand side of said machine (15), wherein 20 torch selection, program of setting parameters, controlling of torch, chuck movement and rotation are controlled by a controlling digital display panel (16) placed adjacent to said machine and connected thereto.
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3. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1 or 2, wherein a plurality of argon cylinders (10) are mounted in a
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stand (11) for manifold and each cylinder outlet is connected to a header (9) through respective connecting hose (8).
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4. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1-3, wherein the outlet of the header (9) is connected to shut off valve (7) and the outlet of the shutoff valve (7) is connected to argon 5 regulator (6).
5. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1-4, wherein 10 CO2 cylinder (12) is kept in another stand (13) and the outlet of CO2 cylinder is connected to the CO2 regulator (14).
6. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection 15 and manual welding process as claimed in claim 1-5, wherein the outlet from argon regulator (6) and the CO2 regulator (14) are connected to the gas mixture unit (5), wherein the outlet of the gas mixture unit (5) is connected to the multiple MIG torches (3) provided in the machine (15) through multiple gas 20 hoses (4).
7. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1-6, wherein 25 the gas mixture unit (5) is having the control nob of both argon and CO2 gas, wherein the nob is adjusted to receive the required mixture of both argon and CO2 gases.
8. The arrangement for uniform gas flow with regulated pressure 30 to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1-7, wherein the manifold header (9) having one opening to fix the shut off
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valve (7), which is attached with regulator (6), outlet of which is having adaptor (107) to connect the gas mixture line.
9. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection 5 and manual welding process as claimed in claim 1-8, wherein multiple openings are provided with studs welded to fix the adaptors (103) for hose connection to cylinders, in which equal number of gas hoses (8) are connected to the header (9) by adaptors (103) and other end of each gas hoses (8) is having 10 adaptor (104) for connecting with the gas cylinders.
10. The arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process as claimed in claim 1-9, wherein the 15 stand (11) is made up of multitude of angles, channels and rods and having the provision to keep four cylinders, wherein a
channel (112) is welded with stand to fix the header firmly, the header is placed on the above channel and fixed with “U” bolt and nut for safe position of header and the lock chain links (113) 20 are provided for the safety of cylinder so as to prevent the cylinders from falling down. , Description:An arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process

FIELD OF INVENTION
[001] The field of the invention is related to an arrangement for 5 uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process.
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BACKGROUND OF THE INVENTION
[002] Steam generators used for power generation have several components like super heaters, re-heaters, economisers and water 15 wall panels. Most of the tube raw materials supplied in length of 10meters by domestic as well as foreign tube suppliers. In re-heater, economisers and super-heater coils have design requirement up to 40 meters length. Hence, in order to get increased length of tubes, “tube to tube butt welding machine” simply known as Straight Tube 20 Butt welding machine (STBW) is employed.
[003] Several materials grades are used in boiler tubes for example carbon steel (Gr A1, Gr C), Low alloy steel (T11, T12 & T23), High alloy steel (T23, T91, T92) and stainless steel (347H, Super304H). 25
[004] During welding, Argon and CO2 gas have been used for shielding purpose in STB machine (as in Figure1). In previous method, only one Argon cylinder and one CO2 cylinder have been
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utilized for shielding purpose. The volume of Argon gas flow is 95% and CO2 flow is 5% and then argon and CO2 gases flow is connected through Gas mixture unit.
[005] The mixed gas flow from the gas mixture unit to the selected torch which are suitable filler wire loaded for the material to be 35 welded.
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[006] Torch selection, program of setting parameters, controlling of torch, chuck movement and rotation are controlled by a controlling digital display panel provided nearby machine.
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[007] The above process gas flow pressure of Argon cylinder to the torch through outlet from the gas mixture is insufficient sometimes due to the pressure variation and purity of the Argon cylinder. So that welding defect occurred like gas hole, multiple porosity, lack of fusion etc. Operators become aware of the reason for the defect due 10 to problem in the argon cylinder, only after results coming out from Real Time Radiography test. Thereafter, the operator changes the cylinder and continues the welding process. This results in frequent change of argon cylinder and high % ge of rejected welding joint.
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[008] The rejected joints are cut and welded manually by Manual TIG welding process centers. The output of the Manual TIG centre is very low when compared with STB machine welding. This leads to high cost of the repairing of defected joints and time delay of handover to shipping. 20
[009] Following data ob Following data ob Following data ob tained on the study of 6months B tained on the study of 6months B tained on the study of 6months B tained on the study of 6months B tained on the study of 6months B tained on the study of 6months Btained on the study of 6months B tained on the study of 6months Btained on the study of 6months B tained on the study of 6months BEFORE INVENTIONINVENTION INVENTIONINVENTION
Table -1 Rate of rejection in the exiting proce rejection in the exiting proce rejection in the exiting proce 25
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[010] Hence, it is very essential to increase the productivity and eliminate the manual TIG welding process by finding a solution to reduce rejection rate in STB joints owing to the gas flow problem.
OBJECTS OF THE INVENTION 5
[011] The object of the present invention is to provide an arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual 10 welding process which is simple.
[012] Another object of the present invention is to provide an arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and 15
manual welding process which reduces the frequent change of argon cylinders.
[013] Yet another object of the present invention is to provide an 20 arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process which reduces the welding rejection rate due to argon gas flow problem.
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[014] Still another object of the present invention is to design an arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process which reduces the manual TIG welding process steps. 30
SUMMARY OF THE INVENTION
[015] Tubes are loaded on the machine stand or rack. Then through tube feeding system, tubes are passed between two chucks on left 35 side and right side. By using the stopper provided between the
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chucks, tubes are halted in correct position and the chucks are clamped to hold the tubes.
[016] For the welding of the tubes suitable filler wire is loaded and for the shielding purpose argon and CO2 cylinders are provided. 5 Both gases are mixed as argon 95% and CO2 5% through a gas mixture.
[017] The mixed gas flows from the gas mixture unit to the selected torch loaded with suitable filler wire for the material to be welded. 10
[018] Torch selection, program of setting parameters, controlling of torch, chuck movement and rotation are controlled by a controlling digital display panel provided nearby machine.
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[019] The manifold header is having one opening to fix the shut off valve. The shut off valve is attached with one regulator and the outlet of the regulator is having adaptor to connect the gas mixture unit. There are for example: four openings with stud welded to fix the adaptors for hose connection to cylinders. Four gas hoses are 20 connected to the header by adaptors and other end of each gas hoses having adaptor for connecting with gas cylinders.
[020] A stand is provided to hold the header of the manifold. The stand is made up of angles, channels and rods. It is having the 25 provision to keep four cylinders and a channel welded with stand to fix the header firmly. The header is placed on the above channel and fixed with “U” bolt and nut for safe position of header. The lock chain links is provided for the safety of cylinder to prevent the fall down of the cylinder. 30
[021] Now the four argon cylinders are loaded in the manifold. The output of the four cylinders connected to a header through hoses of the each cylinder. A shutoff valve is provided to the outlet of the
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header to open or close the gas flow. A regulator is fitted at the downstream of the shutoff valve so as to control the gas pressure and regulate the gas flow. The gas mixture is connected to the outlet of the argon gas regulator. All the four argon cylinders are placed in the stand. At the same time CO2 gas cylinder is placed in the stand. 5
[022] So that the argon gas pressure constantly without variation in pressure due to four cylinders can be connected at same time. Manifold having one header connected to all four argon cylinders through connecting tubes each separately. If there is any deviation 10 in gas purity or pressure in one cylinder, it is corrected by other cylinders while coming into the header. Frequent change of cylinder is also reduced. So that thread damage of cylinder gets reduced avoiding gas leakage with required pressure maintained in the torch.
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BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[023] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and 20 wherein:-
Figure 1 shows: An arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual 25 welding process in accordance with present invention.
Figure 2 shows: Isometric view of header of the present invention.
Figure 3 shows: Stand provided for manifold device according to present invention. 30
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF PREFERRED EMBODIMENTS
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[024] The present invention is directed to a technology relating to an arrangement for uniform gas flow with regulated pressure to straight tube butt welding machine to reduce the rejection and manual welding process. Now, reference may be made to Figure 1 showing the manifold provided for the argon gas cylinders to the Straight tube 5 butt welding machine (15). The two tubes (1) to be welded are clamped in chuck (2) at left side and right side as shown in the figure 1. After clamping the tubes are butted together. Machine (15) having welding torches (3) three in number in this particular embodiment, so that the suitable torch is selected where the required filler wire 10 (17) is loaded.
[025] The mixed gas flows from the gas mixture unit (5) to the selected torch loaded with suitable filler wire (17) for the material to be welded. 15
[026] Torch selection, program of setting parameters, controlling of torch, chuck movement and rotation are controlled by a controlling digital display panel (16) placed nearby said machine and connected thereto. 20
[027] For shielding purpose, Argon gas and CO2 gas are used. A plurality of argon cylinders (10) are mounted in a stand (11) for manifold. Each cylinder outlet is connected to a header (9) through respective connecting hose (8). One CO2 cylinder (12) is kept in 25 another stand (13). The outlet of CO2 cylinder is connected to the CO2 regulator (14). As well as the outlet of the header (9) is connected to shut off valve (7) and the outlet of the shutoff valve (7) is connected to argon regulator (6). The outlet from argon regulator (6) and the CO2 regulator (14) are connected to the gas mixture unit 30 (5). The outlet of the gas mixture unit (5) is connected to the multiple MIG torches (3) provided in the machine (15) through gas hoses (4) as shown in the Figure 1.
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[028] The shutoff valve (7) is opened and the required flow is adjusted through argon regulator (6) as well as CO2 cylinder (12) is opened with adjustment of the required flow through CO2 regulator (14). Now, the gas mixture unit (5) is having the control nob of both argon and CO2 gas. Then the nob is adjusted to get the required 5 mixture of both argon and CO2 gases.
[029] Now the setup is ready to start welding and after completion of welding of full circuit, all joints are checked through Real Time Radiography test. So that in case there is any rejection, the rejected 10
tubes are kept separately and sent to repair centre i.e. Manual TIG welding centre.
[030] Now, reference may be made to figure 2 illustrating the 15 manifold header (9) having one opening to fix the shut off valve (7). The shut off valve is attached with regulator (6), outlet of which is having adaptor (107) to connect the gas mixture line. Multiple openings are provided with studs welded to fix the adaptors (103) for hose connection to cylinders as shown in the figure 2. Equal number 20 of gas hoses (8) are connected to the header (9) by adaptors (103) and other end of each gas hoses (8) is having adaptor (104) for connecting with the gas cylinders.
[031] Further, referring to figure 3 regarding a stand provided to 25 hold the header of said manifold. The stand (11) is made up of multitude of angles, channels and rods as shown in figure 3. It is having the provision to keep four cylinders, wherein a channel (112) is welded with stand to fix the header firmly as shown in the figure. The header is placed on the above channel and fixed with “U” bolt 30 and nut for safe position of header. The lock chain links (113) are provided for the safety of cylinder so as to prevent the cylinders from falling down.
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[032] Now the machine is ready to start welding and after completion of welding of full circuit, all joints are checked through Real Time Radiography test. So that in case there is any rejection,
the rejected tubes are kept separately and supplied to repair centre 5 i.e. Manual TIG welding centre.
[033] Then 6 months reports of rejection rate is collected. After providing this manifold system for argon cylinder of shielding gas, the rejection rate is reduced as shown in the below data. 10
[034] Following data Following data has been has been has been obtain ed duringduring the study of the study of the study of the study of 6months : following present invention
Table-2 Rate of rejection in the modified process 15
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[035] From the above, it is evident that the %ge of repair is less as compared to the prior art depicted in Table-1. Thus, the claimed invention is proved to be more efficient than the known art.
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[036] The advantages of present invention can be listed hereinunder:-
- Reduces the rejection and manual welding process
- Reduces the frequent change of argon cylinders 30
- Less %ge of repair
- Efficient
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- Thread damage of cylinder gets reduced avoiding gas leakage with required pressure maintained in the torch.
[037] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., 5 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 10 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 15 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 particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even 20 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 25 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, 30 typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues 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
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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 5 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 10 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 15 example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[038] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. 20 Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-