DESC:FIELD OF INVENTION
[001] The present subject matter relates to an apparatus for purging gas flow control in straight tube butt welding machine. Particularly, a uniform pressure-based gas flow regulating apparatus, for purging the tubes, to reduce the welding rejection rate due to purging process, and improve productivity.

BACKGROUND/PRIOR ART OF THE INVENTION

[002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[003] Steam generators used for power generation have several components like super heaters, re-heaters, economizers and water wall panels. Most of the tube raw materials supplied in length of 10 meters by domestic as well as foreign tube suppliers. In re-heater, economizers and super-heater coils have design requirement up to 40 meters length. So, in order to get increased length of tubes, “tube to tube butt welding machine” simply known as Straight Tube Butt welding machine (STBW) is used.
[004] 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, Super 304H).
[005] During TIG welding of stainless steel (S304H+S304H) we have been using Argon gas that uses an inert gas purging, which helps to prevent sugaring. Previous method were using two Argon cylinders, for one argon cylinder was connected with TIG torch and another one argon cylinder was used for purging purpose. Torch selection, program of setting parameters, controlling of torch, chuck movement and rotation are controlled by a controlling digital display panel provided nearby machine.
[006] The above process manual purging process required extra manpower for regulating and maintenance of the pressure of purging argon gas and fitting the argon line hose inside every tube. Purging gas flow of Argon cylinder to the torch through outlet from the hose is insufficient sometimes due to the purging gas pressure variation and purity of the Argon cylinder. So that welding defect occurred like gas hole, multiple porosity, lack of fusion, burn through, warm hole etc. Operators know the reason for the defect is that problem in the manual operation of purging argon gas flow cylinder, only after results coming from Real Time Radiography test. Then the manual purging process operation is changed frequently near the waterfall rack and continue the welding process. So that frequent change of manual purging gas flow operation in argon cylinder and rejected welding joint percentage are getting high.
[007] The rejected joints are cut and welded manually by Manual TIG welding process centers. The output of the Manual TIG center is very low when compared with STB machine welding. So that the cost of the repairing of defected joints is more and it also causes a time delay due to handing over the shipping.
[008] Hence it is very essential to increase the productivity and to reduce rejection rate due to purging gas flow problem in Straight Tube Butt welding joints.
OBJECTS OF THE INVENTION
[009] Therefore, an object of the invention is to provide a purging gas flow regulating apparatus that enables uniform and independently controlled purging gas flow in straight tube butt welding machine.
[010] A still further object of the invention is to reduce the welding rejection rate due to purging gas flow problem.
[011] A yet further object of the invention is to reduce the manual operation of purging flow control.
[012] At the outset of the description that follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment and is not intended to be taken restrictively to imply any limitation on the scope of the present invention. These along with other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.

SUMMARY OF THE INVENTION
[013] This summary is provided to introduce the concepts related to purging gas flow control apparatus for straight tube butt welding machine. More specifically, a apparatus capable of regulating gas pressure for tubes purging in straight tube butt welding machine (STBW) machine. Particularly, a uniform pressure-based gas flow regulating apparatus capable of reducing the rejection rates due to fluctuation in purging gas flow and improve productivity.
[014] The apparatus (10) for controlling the flow of an inert gas within the purging gas line (5), the apparatus comprises,
? a flow meter (10a),
? A knob (10b),
? A control unit comprising a transceiver
? A digital display control panel (11) of a straight tube butt welding machine (STBW),
[015] Wherein, the control unit accommodating the transceiver, configured for wireless communication between the knob (10b) and digital display control panel (11). Further the digital display control panel/ board configured for controlling the operations of straight tube butt welding machine (STBW) and remotely supplying a pressure controlled inert gas for purging the tubes (9, 12). The apparatus provides reduction in the rejection rate due to purging gas flow and reduce argon gas wastages, decreases the percentage of repair.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[016] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein: -
[017] The figure-1 shows controlling the consistent supply of the purging gas flow in straight tube butt welding machine (STBW) for root welding of the tubes (9,12) via a flow meter configured within the purging gas line.
[018] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily 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.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[019] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[020] While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiments 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 alternatives falling within the scope of the disclosure.
[021] 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, or 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.
[022] The present invention provides an apparatus for supplying consistent inert gas flow for tubes purging in a straight tube butt welding machine (STBW), wherein straight tube butt welding machine is used for root welding of the tubes. The existing arts lacks providing a consistent flow of the inert gas with required pressure in order to perform purging of the tubes, to remove an oxygen, water vapor, and other gases that can contaminate the weld, ensuring a cleaner, stronger, and more corrosion-resistant joint.
[023] Figure 1 depicts a setup for root welding of tubes (9, 12) held in a straight tube butt welding machine, an inert gas is supplied from a source (1) via a regulator (2), from the regulator (2) said gas line is divided into three, wherein first gas line (3) is configured for supplying gas directly to the mixing chamber (6), supplying mixed gas for Machine inert gas (MIG) based welding. The second gas line (4) is connected to the Tungsten Inert Gas (TIG) torch, supplying the inert gas for TIG based welding. The third gas line (5) i.e. purging gas line is connected to the second tube (12) configured for supplying the inert gas for purging the tubes (9,12) via an apparatus (10). Wherein the apparatus is in wireless communication with the digital display control board (11). In the practical scenarios, the third gas line (5) usually placed at least 500 meters distance from the welding machine, due to which the gas pressure in the purging gas line (5) fluctuates. In the present invention we are providing an apparatus (10) for controlling the purging gas flow within the purging gas line (5).
[024] An apparatus for controlling the flow of an inert gas to the tubes (9, 12), comprises a flow meter (10a), knob (10b), A control unit comprising a transceiver and a digital display control panel (11) of a straight tube butt welding machine (STBW). Wherein, the control unit accommodating the transceiver, configured for wireless communication between the knob and digital display control panel (11).
[025] The knob (10b) in communication with the control unit, control and maintains the consistent flow and pressure of the inert gas supplying inside the purging gas line.
[026] The purging gas line (5) is connected directly to the second tube (12) for supplying inert gas.
[027] The apparatus (10) is accommodated within the purging gas line (5).
[028] The purging gas line (5) connected to a inert gas source (1) via a regulator (2) for supplying purging gas directly to a second tube (12). The flow meter (10a) configured to display gas flow pressure within the purging gas line (5).
[029] The digital display control panel/ board (11) controls the knob (10b) wirelessly through the control unit.
[030] The control unit configured to the knob (10b) receives signal from the digital display control panel for controlling the inert gas supply within the purging gas line. Wherein, the purging gas also referred as the inert gas in the present disclosure is selected from an argon gas.
[031] The digital display control panel (11) configured to send start/ stop signal to the knob (10b) through the control unit.
[032] The control unit configured to the knob (10b), start or stops the inert gas flow according to the received signal from digital display control panel (11).
[033] In another embodiment of the invention, wherein the control unit may comprise a micro controller, a transceiver, an antenna and a battery as power source.
[034] In an embodiment of the invention, the apparatus supplies the purging gas with rate ranging from 15-20 Litre per minute (LPM).
[035] In an embodiment of the invention, an apparatus (10) for controlling the flow of purging gas within the purging gas line (5), comprising:
? a flow meter (10a),
? a knob (10b),
? a control unit comprising a transceiver,
? a digital display control panel (11) of a straight tube butt welding machine (STBW),
wherein, the apparatus (10) accommodated within the purging gas line (5),
wherein, the control unit accommodating the transceiver, configured for wireless communication between the knob (10b) and digital display control panel (11).
[036] In an embodiment of the invention, the knob (10b) in communication with the control unit, controls and maintains the consistent flow and pressure of the purging gas supplied inside the purging gas line (5).
[037] In an embodiment of the invention, the purging gas line (5) connected to a gas source (1) via a regulator (2) configured for supplying purging gas directly to a second tube (12).
[038] In an embodiment of the invention, the flow meter (10a) configured to display gas flow pressure within the purging gas line (5).
[039] In an embodiment of the invention, the digital display control panel (11) controls the knob (10b) wirelessly through the control unit.
[040] In an embodiment of the invention, the control unit configured to the knob (10b) receives signal from the digital display control panel (11) for controlling the purging gas supply within the purging gas line (5).
[041] In an embodiment of the invention, the purging gas is selected from an inert gas including argon gas.
[042] In an embodiment of the invention, the digital display control panel (11) configured to send start/ stop signal to the knob (10b) through the control unit.
[043] In an embodiment of the invention, the digital display control panel (11) further configured to control straight tube butt welding machine (STBW) machine’s operations including torch selection, program of setting parameters, torch, chuck movement and rotation.
EXPERIMENT AND RESULT
[044] Furthermore, the figure (5) depicts a straight tube butt welding machine (STBW) machine, wherein tubes (9,12) are loaded on the machine stand or rack. Then through tube feeding system, tubes are provided, and the chucks are clamped to hold the tubes. Wherein, tubes (9,12) are halted in correct position using stopper provided between the chucks. For the purpose of welding the tubes suitable filler wire can be loaded.
[045] In a straight tube butt welding machine as shown in figure 1, an inert gas is supplied from a source (1) via a regulator (2), from the regulator (2) said gas line is divided into three, wherein first gas line () is configured for supplying gas directly to the mixing chamber (6), supplying mixed gas for Machine inert gas (MIG) based welding. The second gas line () is connected to the Tungsten Inert Gas (TIG) torch, supplying the inert gas for TIG based welding. The third gas line (5) i.e. purging gas line is connected to the second tube (12) configured for supplying the inert gas for purging the tubes (9,12) via an apparatus (10). Wherein the apparatus is in wireless communication with the digital display control board (11).
[046] According to an embodiment of the invention, the digital display control panel, configured for controlling the torch selection, program of setting parameters, chuck movement and rotation.
[047] The digital display control panel is in wireless communication with communication with a knob (10b), is positioned proximate to a flow meter (10a) as shown in figure (1). The stand and lock chain links are provided for the safety of argon cylinder (1).
[048] The knobs (10b) is controlled by digital display control panel/ board (11), which regulates flow of inert gas with required gas pressure rate ranges from 15 LPM to 20 LPM. The inert gas is supplied to the purging gas line (5) which is connected to the second tube (12) and its flow is controlled using an apparatus (10) based on the wireless communication with digital display control board (11).
[049] After completion of tubes welding, all joints are checked through Real Time Radiography test. Said test helps to identify rejected pieces that are not up to the task, then these rejected tubes are kept separately and sent to repair centre i.e. Manual TIG welding centre.
[050] Then 3 months reports of rejection rate is collected. After providing the Purging gas flow process unit for TIG welding butt joints, the rejection rate is reduced as can be seen below.
TEST RESULT
• Table 1 represent the plurality of tubes with varying length are welded, wherein the range of purging gas supply is controlled according to the requirement.
Tube Diameter to thick ness Tube length Material Range (LPM)
44.5X7.1 2000 mm to 3000 mm S304H 10 – 12
44.5X7.1 3000 mm to 6000 mm S304H 12 – 15
44.5X7.1 6000 mm to 12000 mm S304H 15 – 20
50.8x8.6 2000 mm to 12000 mm S304H 20

• Table 2 represent the data obtained by 3 months study. which describes the Rejection percentage before application of the apparatus (10):

MONTH WELDED OK REPAIR LF GH BT MP WH % Repair
April 750 675 77 12 15 18 20 12 10.26
May 790 719 71 9 20 15 17 10 8.98
June 780 694 88 12 18 18 20 20 11.28
TOTAL 2320 2088 236 39 53 51 57 42 10.17

• Table 3 represent data obtained after 3 months study, where lower rejection percentages can be observed.
(Rejection % After)
MONTH WELDED OK REPAIR LF GH BT MP WH % Repair
July 1250 1178 72 11 17 16 16 12 5.76
Aug 1450 1368 82 13 20 18 17 14 5.65
Sep 1540 1449 89 18 22 19 15 15 5.77
TOTAL 4240 3995 243 42 59 53 48 41 5.72

ADVANTAGES OF INVENTION
[051] The present apparatus provides following advantages:
? Reduces the rejection due to purging process.
? Reduce argon gas wastages.
? Less percentage of repair.
[052] 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 by devising various systems 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 further 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.
[053] 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.

,CLAIMS:We Claim
1. An apparatus (10) for controlling flow of purging gas within a purging gas line (5), comprising:
a flow meter (10a);
a knob (10b);
a control unit comprising a transceiver;
a digital display control panel (11) of a straight tube butt welding machine (STBW);
wherein, the apparatus (10) accommodated within the purging gas line (5),
wherein, the control unit accommodating the transceiver, configured for wireless communication between the knob (10b) and digital display control panel (11).
2. The apparatus (10) as claimed in claim 1, wherein the knob in communication with the control unit, controls and maintains the consistent flow and pressure of the purging gas supplied inside the purging gas line (5).
3. The apparatus (10) as claimed in claim 1, wherein the purging gas line (5) connected to a gas source (1) via a regulator (2) configured for supplying purging gas directly to a second tube (12).
4. The apparatus (10) as claimed in claim 1, wherein the flow meter (10a) configured to display gas flow pressure within the purging gas line (5).
5. The apparatus (10) as claimed in claim 1, wherein the digital display control panel (11) controls the knob (10b) wirelessly through the control unit.
6. The apparatus (10) as claimed in claim 5, wherein the control unit operates knob (10b) relying on a signal from the digital display control panel (11) for controlling purging gas supply within the purging gas line (5).
7. The apparatus (10) as claimed in claim 1, wherein the purging gas is selected from an inert gas including argon gas.
8. The apparatus (10) as claimed in claim 5, wherein the digital display control panel (11) configured to send start/ stop signal to the knob (10b) through the control unit.
9. The apparatus (10) as claimed in claim 1, wherein the apparatus controls the purging gas flow within the purging gas line (5) at a rate ranging from 15-20 Litre per minute (LPM).
10. The apparatus (10) as claimed in claim 1, wherein the digital display control panel (11) configured to control straight tube butt welding machine (STBW) machine’s operations including torch selection, program of setting parameters, torch, chuck movement and rotation.