FIELD OF INVENTION
Present invention relates to an arrangement and method for heating CO2 gas with improved heating element for straight tube butt welding machine. More, particularly, the invention relates to heating of CO2 gas more efficiently which is used for Gas Metal Arc Welding (GMAW) process to avoid frequent freezing of the said gas causing porosity in the weld. The method reduces porosity and thus improves the quality of the weld.
BACKGROUND OF THE INVENTION AND PRIOR ART
CO2 gas is used in GMAW process in Straight Tube Butt Welding machines for the welding of tube to tube butt joints for manufacturing of boiler components like water wall panels, superheater, reheater and economizer coils. To avoid freezing up of CO2 gas in the regulator, a conventional CO2 heater was being used in Straight Tube Butt STBW machines. But at times, heating using the conventional CO2 heater was not efficient and frequent freeze up problems were happening which was creating porosity in the weld. To eliminate the issue of freeze up and thereby the weld porosity, a modified CO2 gas heating element has been designed.
This modified design of CO2 gas heating element improves the heat transferred to the CO2 gas, thereby eliminating the risk of frequent freeze up and welding issues related to this. This invention improves the quality of welding and also reduces the downtime of the welding machines, thereby increasing productivity.

This invention relates to an improved method of heat transfer to the CO2 gas in the heating element to avoid freeze up of CO2 gas. This invention relates to improved CO2 gas heating method in Straight Tube Butt Welding machines, which reduces welding defects such as porosity, worm holes, multiple porosity, etc. This invention relates to an efficient method of heating any gas which is prone to freezing up.
OBJECT OF THE INVENTION
Therefore, it is an object of the invention to propose an arrangement and method for heating CO2 gas with improved heating element for straight tube butt welding machine, which is capable of transferring more heat to CO2 gas reducing the chance of the said gas getting freezed.
Another object of the invention is to propose an arrangement and method for heating CO2 gas with improved heating element for straight tube butt welding machine, which ensures higher productivity by reducing downtime of the welding machine caused by freezing of CO2 gas in pressure regulators and other compressed gas equipment.
A still another object of the invention is to propose an arrangement and method for heating CO2 gas with improved heating element for straight tube butt welding machine, which is able to improve quality of the weld.

SUMMARY OF THE INVENTION
An improved method for heating CO2 gas in Straight Tube Butt Welding machines. This method improves the weld quality by eliminating porosity issues due to freeze up of CO2 gas in pressure regulators and other compressed gas equipment. In the present invention, the gas heating element is designed such that the CO2 gas remains in contact with the heating element for sufficiently longer duration compared to the conventional heating element, thereby increasing the heat transferred to the CO2 gas. A square threaded groove is made on the outer surface of the heating element forming a spiral path. A hole in the element guides the CO2 gas to the surface from the inside of the heating element. The gas is allowed to pass in a spiral way through the square groove surrounding the heating element to which electrical supply is given, whereas in the conventional design, the CO2 gas passes in a straight path through the inside of the heating element. The longer the gas remains inside the heating element, more the heat transferred to the CO2 gas and less the chance of gas getting freezed up. A bush is provided on the outer surface of the element which guides the CO2 gas and eliminates any risk of CO2 gas leakage. The new design is simple in construction and easy to use. It improves the efficiency of heating of CO2 gas, thus does not allow CO2 gas to get condensed in the regulators and other components. It also improves the weld quality by making sure that sufficient quantity of gas is supplied to the welding torch.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1: shows the existing heating element in CO2 heater for heating CO2 gas. Figure 2: shows the newly designed CO2 heating element with improved heating
efficiency. Figure 3: shows the Copper bush which is soldered to the heating element for
guiding the flow of CO2 gas. Figure 4: shows the arrangement of modified CO2 heater inside CO2 heater in the
gas line.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
In the existing setup, the CO2 heater (1) comprised of a heating element (2) in which the CO2 gas from the CO2 cylinder (12) enters through inlet (3) and passes through the heating element in a straight line, during which the gas gets heated up by the electrical current supplied to the heating element. The heated gas exits through the outlet (4) to the welding torch (13). A square threaded groove (8) is made on the outer surface of the heating element (5) that forms the spiral path (8) of the heating element. The groove is made square of the heating element. The groove is made square to maximize the flow of CO2. The width and depth of the groove are 4 mm and 2 mm respectively and the pitch is 8mm. Also the newly invented heating element (5) has a spiral path (8)

made on its outer surface to increase the time the CO2 gas remains in contact with the heating element. The CO2 gas enters the heating element through inlet hole (3) and is guided to the spiral path through a hole (6). A pressure regulator regulates the pressure of CO2 gas before entering the hole (3). The hole (6) guides the CO2 gas to the surface from the inside of the heating element. The CO2 gas is now forced to take a spiral path surrounding the heating element by means of a Copper bush (9) soldered to the outside surface of the heating element. This Copper bush prevents the CO2 gas from escaping to the atmosphere. The more the time the CO2 gas remains in contact with the heating element, the more will be the heat absorbed by the gas. A hole (7) provided at the end of the spiral path guides the CO2 gas from the outer surface of the heating element to the inner region, from where the gas flows to the torch (13) through the outlet hole (4). The pressure regulator (10) control the flow of CO2 to the torch (13). The heating element is made of brass.

WE CLAIM
1. An arrangement for heating CO2 gas with improved heating element for straight
tube butt welding (STBW) machine, the said arrangement comprising;
a CO2 cylinder (12);
a pressure regulator (10) for regulating the pressure of CO2;
a CO2 heater (1) comprising;
an inlet hole (3) for allowing CO2 gas to enter the heater;
a square threaded groove configured on the outer surface of the heating element (5) forming a spiral path (8) of the heating element;
an outlet hole (4) for allowing heated CO2 gas to exit;
Characterized in that,
a heating element (5) with a spiral path (8) made on the outer surface of the said element (5) is disposed inside the heater when CO2 gas entesr through hole (3) and is guided through a hole (6) to pass in a spiral way through the square threaded groove (8) surrounding the heating element, the said element being connected to an electric supply source wherein a copper bush (9) is soldered to the outside surface of the heating element (5) for forcing the said CO2 gas to take the spiral path so that CO2 gas remains in contact with the heating element for a longer period,
wherein a hole (7) is configured at the end of the spiral path (8) for guiding the heated CO2 gas from the outer surface of the heating element to the inner region for providing sufficient quantity of heated CO2 gas to the welding torch (13) through the outlet hole (4).
2. The arrangement as claimed in claim 1, wherein the heating element is made of
brass.

3. The arrangement as claimed in claim 1, wherein the square threaded groove has the width of 4mm, depth of 2mm and pitch of 8mm.
4. A method for heating CO2 gas with improved heating element for straight tube butt welding comprising;
passing CO2 gas from CO2 cylinder (12) to a heating element (5) having spiral Path, through an inlet hole (3);
guiding the CO2 gas to the spiral path through a hole (6) to allow the said gas to remain in contact with the heating element (5) for a longer period;
forcing the said CO2 gas to traverse the spiral path surrounding the heating element (5) by means of a copper bush (9) soldered to the outside surface of the heating element (5);
Wherein a hole (7) is configured at the end of the spiral path to guide the said heated CO2 gas from the outer surface of the heating element (5) to the inner region to deliver the said gas to a welding torch (13) through the outlet hole (4).