Crater, heating torch using it, and gas pressure welding method

Abstract

A nozzle capable of suppressing overheating of the nozzle during gas pressure welding of pressure welding members and preventing backfire from occurring inside the nozzle is provided. [Solution] The nozzle A2 comprises a nozzle base a with a gas guide path 5 provided inside in the longitudinal direction, a dome portion 4 provided at the tip of the nozzle base a and having an outer shape that is approximately partially spherical, and fire holes 403, 404, 405 provided in a predetermined arrangement that penetrate the inner and outer surfaces of the dome portion 4 and connect to the gas guide path 5.

Description

[Technical Field]

[0001] The present invention relates to a nozzle, a heating torch using the nozzle, and a gas pressure welding method. More specifically, the present invention relates to a nozzle that can prevent overheating of the nozzle during gas pressure welding of pressure welding members, thereby preventing backfires from occurring inside the nozzle. [Background technology]

[0002] In gas pressure welding of press-welded members such as reinforcing bars using combustible gas, a heating torch 90 having a predetermined number of nozzles B is used to heat the press-welded members 91, 92 (see FIG. 11). An example of such a nozzle is the nozzle disclosed in Patent Document 1 proposed by the present applicant. This conventional nozzle has a nut-like tip and a generally flat tip surface 93.

[0003] In order to accurately apply the flame to the pressure-contact members 91, 92, each nozzle B must be set so that its tip surface 93 is at a predetermined distance from the pressure-contact members 91, 92; this distance is usually relatively short, and each nozzle B is heated by the reflected heat of the flame that hits the pressure-contact members 91, 92 and the radiant heat of the heated pressure-contact members 91, 92. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7510225 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as described above, the tip surface 93 of the burner B is approximately flat, and the distances of the tip surface 93 from the pressure contact members 91 and 92 are approximately the same. For this reason, the reflection of the flame that hits the pressure contact members 91 and 92 and the radiant heat of the heated pressure contact members 91 and 92 strongly heat the tip surface 93 of the burner B and the parts connected to it, so that the entire burner B is likely to overheat and reach a considerably high temperature. This caused the combustible gas inside nozzle B to ignite during the welding process, creating a problem of backfire.

[0006] The present invention has been devised in consideration of the above points, and aims to provide a nozzle that can prevent overheating of the nozzle during gas pressure welding of pressure-welded members and prevent backfires from occurring inside the nozzle, as well as a heating torch and gas pressure welding method that use the same. [Means for solving the problem]

[0007] [1] In order to achieve the above object, the present invention provides a crater comprising a crater base having a gas guide path provided inside in the longitudinal direction, a dome portion provided at the tip of the crater base and having an outer shape that is approximately partially spherical, and fire holes in a predetermined arrangement that penetrate the inner and outer surfaces of the dome portion and are connected to the gas guide path.

[0008] The nozzle of the present invention is provided with a nozzle base having a gas guide path provided inside in the longitudinal direction, so that the combustible gas can be supplied by passing the combustible gas through the gas guide path of the nozzle base. Also, the nozzle base is provided with a dome portion having a substantially partially spherical outer shape at the tip, so that the dome portion can be positioned close to the pressure-welded member at a predetermined distance.

[0009] Furthermore, because the dome portion is approximately partially spherical, when the apex is positioned a predetermined distance from the workpiece, the other curved portions extending from the apex to the base of the dome portion gradually become farther away from the workpiece, thereby suppressing or mitigating overheating caused by the reflection of flames that strike the workpiece being heated during gas pressure welding and the radiant heat of the workpiece. This makes it difficult for the combustible gas inside the nozzle to ignite during gas pressure welding, making it possible to prevent backfires.

[0010] [2] The burner of the present invention may be configured to be rotatable in the circumferential direction around the apex of the dome portion and to be fixed at a predetermined position.

[0011] In this case, since the burner can rotate in the circumferential direction centered on the apex of the dome part and can be fixed at a predetermined position even after the burner is attached, the burner holes (or appropriately arranged burner holes) in a predetermined arrangement provided in the dome part can be rotationally moved to adjust the position.

[0012] For example, if the burner holes are at two locations sandwiching the apex of the dome part at a predetermined distance, (1) when the angle formed by the "line connecting the two burner holes" and the "pressure contact surface" is 90°, the heating power with respect to the pressure contact surface is minimized, (2) when the angle formed by the "line connecting the two burner holes" and the "pressure contact surface" is 0°, the heating power with respect to the pressure contact surface is maximized, and (3) when the angle X formed by the "line connecting the two burner holes" and the "pressure contact surface" is 0° < X < 90°, there are three patterns such that the heating power with respect to the pressure contact surface is medium. For (3), continuous adjustment is possible such that the smaller X is, the greater the heating power.

[0013] On this premise, when switching the type of combustible gas, that is, when applying the reducing flame of acetylene gas to the pressure contact surface in (2) and applying the standard flame (neutral flame, oxidizing flame) of natural gas or propane gas (hereinafter referred to as propane gas) near the pressure contact surface instead of to the pressure contact surface in (1) and (3), such adjustment becomes possible.

[0014] Also, when 0° < X < 90°, since the distance from each burner hole to the pressure contact surface changes, the heating power with respect to the pressure contact surface can be adjusted according to the set angle. Thereby, regardless of whether the combustible gas used is acetylene gas or propane gas, the flame can be appropriately adjusted to correspond to steel grades with different resistances to rapid heating and rapid cooling of the pressure contact member.

[0015] In this way, by attaching the burner so that the position (arrangement) of the burner holes becomes an appropriate one among the above (1), (2), and (3), or by rotationally adjusting (adjusting) in the circumferential direction after attachment, gas pressure welding operations for heating the pressure-welded member according to the combustible gas used and the steel grade can be performed.

[0016] [3] The burner of the present invention can also be configured such that, in the burners of [1] and [2] above, the burner holes are substantially round and are provided at two positions sandwiching the apex of the dome portion with a predetermined distance therebetween.

[0017] In this case, since the burner holes are substantially round and are provided at two positions sandwiching the apex of the dome portion with a predetermined distance therebetween, the positions of the respective burner holes can be selectively used in an arrangement where "the flames ejected from the respective burner holes hit the pressure contact surface of the pressure contact member (using acetylene gas)" and an arrangement where "the flames ejected from the respective burner holes do not hit the pressure contact surface of the pressure contact member and the vicinity of the pressure contact surface can be heated (using propane gas)".

[0018] Note that in the arrangement where "the flames ejected from the respective burner holes hit the pressure contact surface of the pressure contact member", the heating power with respect to the pressure contact surface is maximized. Also, in the arrangement where "the flames ejected from the respective burner holes do not hit the pressure contact surface of the pressure contact member and the vicinity of the pressure contact surface can be heated", when the angle formed by the straight line connecting the respective burner holes and the pressure contact surface is 90°, the heating power with respect to the pressure contact surface is minimized.

[0019] Further, when the angle X formed by the straight line connecting the respective burner holes and the pressure contact surface is 0° < X < 90°, since the distance of each burner hole from the pressure contact surface changes, the heating power with respect to the pressure contact surface can be adjusted according to the set angle. Thereby, the flame can be appropriately adjusted corresponding to steel types having different resistances to rapid heating and rapid cooling of the pressure contact member.

[0020] Also, in the arrangement where "the flames ejected from the respective burner holes do not hit the pressure contact surface of the pressure contact member and the vicinity of the pressure contact surface can be heated", heating using the standard flame of propane gas is possible.

[0021] [4] The burner of the present invention can also be configured such that, in the burners of [1] and [2] above, the burner holes are substantially round and are provided at a total of three positions, namely, one position at the apex of the dome portion and two positions sandwiching the apex with a predetermined distance therebetween.

[0022] In this case, the flame holes are of a substantially round shape and are provided at a total of three locations, namely, one location at the apex of the dome portion and two locations sandwiching the apex with a predetermined distance therebetween. Therefore, the positions of the respective flame holes can be selectively used in an "arrangement in which the flames ejected from each flame hole hit the pressure contact surface of the member to be pressure contacted (when using acetylene gas)" and an "arrangement in which only the flame ejected from the one central flame hole hits the pressure contact surface of the member to be pressure contacted (when using acetylene gas)", and the heat power for heating the pressure contact surface can be properly allocated.

[0023] Note that in the "arrangement in which the flames ejected from each flame hole hit the pressure contact surface of the member to be pressure contacted", the heat power with respect to the pressure contact surface is maximized. Also, with respect to the heat power on the pressure contact surface by the flames ejected from the two flame holes (the two flame holes other than the one at the apex of the dome portion) sandwiching the apex of the dome portion with a predetermined distance therebetween, when the angle formed by the straight line connecting the respective flame holes and the pressure contact surface is 90°, the heat power with respect to the pressure contact surface is minimized.

[0024] Further, when the angle X formed by the straight line connecting the respective flame holes and the pressure contact surface is such that 0° < X < 90°, since the distance of each flame hole from the pressure contact surface changes, the heat power with respect to the pressure contact surface can be adjusted according to the set angle. Thereby, the flame can be properly adjusted in correspondence with steel types having different resistances to rapid heating and rapid cooling of the pressure contact member.

[0025] 〔5〕The burner of the present invention, in the burners of the above 〔1〕 and 〔2〕, may be configured such that the flame holes are of a substantially round shape and are provided at a total of four locations, namely, two locations sandwiching the apex of the dome portion with a predetermined distance therebetween and two locations sandwiching the apex of the dome portion with a predetermined distance therebetween at an angle of 90° in the circumferential direction centered on the apex from the two locations.

[0026] In this case, the fire holes are approximately round in shape and are provided in a total of four locations: two locations on either side of the apex of the dome portion at a specified distance, and two locations on either side of the apex of the dome portion at a 90° angle in the circumferential direction from the two locations, also at a specified distance.Therefore, the positions of the fire holes can be selectively used as follows: "an arrangement in which the flames sprayed from each of the two diagonally positioned fire holes hit the press-welded surface of the pressed-welded parts (acetylene gas is used)"; or "an arrangement in which the flames sprayed from each of the fire holes do not hit the press-welded surface of the pressed-welded parts, and the flames sprayed from the two fire holes on either side of the press-welded surface can heat the area near the press-welded surface (propane gas is used)."

[0027] In addition, when the "arrangement is such that the flames ejected from two diagonally positioned fire holes strike the press-welded surfaces of the press-welded members," the fire power on the press-welded surfaces is maximized. Furthermore, when the angle between the "straight line connecting the two diagonally positioned fire holes" and the pressure contact surface is 45°, the fire power on the pressure contact surface will be minimal.

[0028] Furthermore, in the case of an arrangement in which the flames ejected from each hole do not hit the welded surfaces of the components being welded, and the flames ejected from two holes on either side of the welded surfaces can heat the area around the welded surfaces, the heat intensity on the welded surfaces can be adjusted by changing the arrangement of the holes (the distance of the holes from the welded surfaces). This allows the flame to be adjusted appropriately to accommodate the different steel types of welded components, which have different resistance to rapid heating and cooling.

[0029] In addition, by "arranging the flames from each nozzle so that they do not hit the pressure-welding surface of the workpiece, and by using flames from two nozzles positioned on either side of the pressure-welding surface to heat the area near the pressure-welding surface," heating using a standard propane gas flame is possible.

[0030] [6] The burner of the present invention may be configured such that, in the burner of [1] and [2] above, the fire holes are approximately round and are provided at a total of five locations: one at the apex of the dome portion, two locations on either side of the apex at a predetermined distance, and two locations on either side of the apex of the dome portion at an angle of 90° in the circumferential direction around the apex from the two locations, and at a predetermined distance.

[0031] In this case, the fire holes are approximately round in shape and are provided in a total of five locations: one at the apex of the dome, two on either side of the apex at a specified distance, and two on either side of the apex of the dome at a 90° angle in the circumferential direction from the second location, each at a specified distance.Therefore, the positions of the fire holes can be selectively used in either an "arrangement in which the flames sprayed from the three diagonal fire holes hit the welded surface of the parts being pressed together (acetylene gas is used)" or an "arrangement in which only the flame sprayed from the central fire hole hits the welded surface of the parts being pressed together (acetylene gas is used)", allowing different amounts of heat to be used to heat the welded surface.

[0032] In addition, when the "arrangement is such that the flames ejected from the three diagonally positioned fire holes hit the press-welded surfaces of the press-welded members," the fire power on the press-welded surfaces is maximized. Furthermore, if the angle between the "straight line connecting the three diagonal fire holes" and the pressure contact surface is 45°, the fire power on the pressure contact surface will be minimal.

[0033] In addition, in the case of an arrangement in which only the flame emitted from one central fire hole strikes the welded surface of the pressed parts, the flame power on the welded surface can be adjusted by changing the arrangement of the fire holes (the distance from the welded surface of the fire hole). This allows the flame to be adjusted appropriately to accommodate the different steel types of pressed parts that have different resistance to rapid heating and cooling.

[0034] [7] The burner of the present invention can also be configured such that, in the burners of [1] and [2] above, the fire holes are approximately round in shape and are provided at a total of six locations, two of which sandwich the apex of the dome portion at a predetermined distance, and four of which sandwich each of the two locations at a predetermined distance in a direction perpendicular to the line connecting the two locations when viewed from the longitudinal direction of the burner base.

[0035] In this case, the fire holes are approximately round in shape and are provided in a total of six locations: two locations on either side of the apex of the dome portion at a specified distance, and four locations on either side of these two locations at a specified distance when viewed from the longitudinal direction of the nozzle base, perpendicular to the line connecting these two locations.Therefore, the positions of the fire holes can be selectively used as follows: ``An arrangement in which the flame sprayed from each of the two fire holes that are on either side of the apex of the dome portion at a specified distance hits the press-welded surface of the pressure-welded parts (acetylene gas is used)'', and ``An arrangement in which the flame sprayed from each fire hole does not hit the press-welded surface of the pressure-welded parts, and the flame sprayed from two rows of fire holes each consisting of three locations can heat the area near the press-welded surface on either side of the press-welded surface (propane gas is used).''

[0036] In addition, when the arrangement is such that the flames ejected from two fire holes that are spaced a specified distance apart from the apex of the dome hit the press-welded surface of the press-welded member, the fire power on the press-welded surface is maximized. Furthermore, when the angle between the "straight line connecting the two fire holes that sandwich the apex of the dome at a specified distance" and the pressure contact surface is 90°, the fire power on the pressure contact surface will be minimal.

[0037] Furthermore, in the case of an arrangement in which the flames ejected from each hole do not hit the welded surfaces of the pressure-welded parts, and the flames ejected from two rows of three holes each can heat the areas adjacent to the welded surfaces, it is possible to adjust the heat intensity on the welded surfaces by changing the arrangement of the holes (the distance of the holes from the welded surfaces).This makes it possible to adjust the flame appropriately to suit the steel types of pressure-welded parts, which have different resistance to rapid heating and cooling.

[0038] In addition, "an arrangement in which the flames ejected from each nozzle do not hit the press-welded surface of the workpiece, and the flames ejected from two rows of three nozzles each can heat the areas adjacent to the press-welded surface," makes it possible to heat using a standard propane gas flame.

[0039] [8] The nozzle of the present invention can also be configured such that, in the nozzles of [1] and [2] above, the fire holes are approximately slit-shaped and are provided at two locations that sandwich the apex of the dome portion at a predetermined distance from each other and are parallel to each other when viewed from the longitudinal direction of the nozzle base.

[0040] In this case, the fire holes are roughly slit-shaped and are provided in two locations that are parallel to each other and spaced a predetermined distance apart from the apex of the dome portion when viewed from the longitudinal direction of the nozzle base. Therefore, the position of each fire hole can be selectively used in either an "arrangement that allows part of the flame ejected from the center of each fire hole to hit the press-welded surface of the pressed-welded part (acetylene gas is used)" or an "arrangement that prevents the flame ejected from each fire hole from hitting the press-welded surface of the pressed-welded part and can heat two locations near the press-welded surface that are sandwiched between the press-welded surface (propane gas is used)."

[0041] In addition, in the "arrangement in which a part of the flame ejected from the center of each fire hole strikes the press-welded surface of the press-welded member," the fire power on the press-welded surface is maximized. Furthermore, when the angle between each fire hole and the pressure contact surface is 0°, the fire power on the pressure contact surface is minimum.

[0042] Furthermore, in the case of an arrangement in which the flames ejected from each nozzle do not hit the welded surfaces of the pressure-welded parts, and can heat two points near the welded surfaces on either side, it is possible to adjust the heat applied to the welded surfaces by changing the arrangement of the nozzles (the distance from the welded surfaces to the nozzles). This allows the flame to be adjusted appropriately to accommodate the different steel types of pressure-welded parts, which have different resistance to rapid heating and cooling.

[0043] [9] The nozzle of the present invention can be configured such that, in the nozzles of [1] and [2] above, the fire holes are approximately slit-shaped and are provided at three locations in total: one location passing through the apex of the dome portion, and two locations sandwiching the apex at a predetermined distance from each other and parallel to each other when viewed in the longitudinal direction of the nozzle base.

[0044] In this case, the fire holes are roughly slit-shaped and are provided in three locations: one that passes through the apex of the dome portion, and two that are parallel to each other and spaced a specified distance from the apex when viewed along the length of the nozzle base.Therefore, the position of each fire hole can be selectively used in either an ``arrangement in which part of the flame sprayed from the center of each fire hole hits the pressure welding surface of the material to be welded (acetylene gas is used)'' or an ``arrangement in which all of the flame sprayed from the fire hole that passes through the apex of the dome portion hits the pressure welding surface of the material to be welded (acetylene gas is used)'', allowing different amounts of heat to be used to heat the pressure welding surface.

[0045] In addition, in the "arrangement in which all of the flames ejected from the fire holes passing through the apex of the dome portion strike the press-welded surfaces of the members to be press-welded," the fire power on the press-welded surfaces is maximized.

[0046] In addition, except for the "arrangement so that the entire flame ejected from the fire holes passing through the apex of the dome hits the press-welded surface of the workpiece," the heat intensity on the press-welded surface can be adjusted by the arrangement of the fire holes (the distance of the fire holes from the press-welded surface). This allows the flame to be adjusted appropriately to accommodate the different steel types of press-welded workpieces that have different resistance to rapid heating and cooling.

[0047] According to the nozzles [2] to [9] subordinate to the above [1], it is possible to provide a nozzle that can suppress overheating of the nozzle during gas pressure welding of the pressure welding member and prevent backfire from occurring inside the nozzle.

[0048]

[10] In order to achieve the above object, the present invention provides a heating torch comprising: a nozzle base attached to the burner tube and having a gas guide path provided inside in the longitudinal direction; a nozzle provided at the tip of the nozzle base and having a dome portion with an outer shape that is approximately partially spherical; and a nozzle having fire holes in a predetermined arrangement that penetrate the inner and outer surfaces of the dome portion and are connected to the gas guide path.

[0049] The heating torch of the present invention is provided with a nozzle base having a gas guide path provided in the length direction inside the nozzle, so that the combustible gas can be supplied by passing the combustible gas through the gas guide path of the nozzle base. Also, the nozzle base is provided with a dome portion having a substantially partially spherical outer shape at the tip, so that the dome portion can be positioned close to the pressure-welded member at a predetermined distance.

[0050] The dome portion of the nozzle is approximately partially spherical, so when the apex is positioned a predetermined distance from the workpiece, the other curved portions extending from the apex to the base of the dome are gradually moved away from the workpiece, thereby suppressing or mitigating overheating caused by the reflection of flames hitting the workpiece being heated during gas pressure welding or by radiant heat from the workpiece. This makes it possible for the heating torch of the present invention to prevent backfires from occurring inside the nozzle during gas pressure welding.

[0051]

[11] The heating torch of the present invention may be configured as the heating torch of

[10] above, so that it can rotate in the circumferential direction around the apex of the dome portion and can be fixed at a predetermined position.

[0052] In this case, even after the burner is installed, it can be rotated in a circumferential direction around the apex of the dome portion and can be fixed in a predetermined position, so that the position of the predetermined arrangement of fire holes (or appropriately arranged fire holes) provided in the dome portion can be adjusted.

[0053]

[12] In order to achieve the above object, the present invention provides a gas pressure welding method comprising: a nozzle comprising a nozzle base having a gas guide path provided inside in the longitudinal direction, a dome portion having an outer shape of an approximately partially spherical surface provided at the tip of the nozzle base, and fire holes in a predetermined arrangement that penetrate the inner and outer surfaces of the dome portion and connect to the gas guide path, and the method comprises the step of using a heating torch attached to a burner tube to apply flames ejected from the fire holes to the pressure-welded members to heat the pressure-welded members.

[0054] The gas pressure welding method of the present invention uses a nozzle having a nozzle base with a gas guide path provided in the length direction inside the nozzle, so that the combustible gas can be supplied by passing it through the gas guide path in the nozzle base. Furthermore, the nozzle is provided at the tip of the nozzle base and has a dome portion with an outer shape that is approximately partially spherical, so that the dome portion can be positioned close to the workpiece at a predetermined distance.

[0055] The dome portion of the nozzle is approximately partially spherical, so when the apex is positioned a predetermined distance from the workpiece, the other curved portions extending from the apex to the base of the dome are gradually moved away from the workpiece, thereby suppressing or mitigating the reflection of flames that strike the workpiece being heated during gas pressure welding, and the overheating caused by the radiant heat of the workpiece. As a result, the gas pressure welding method of the present invention makes it possible to prevent backfires from occurring inside the nozzle during gas pressure welding.

[0056]

[13] The gas pressure welding method of the present invention may be configured such that, in the gas pressure welding method of

[12] above, the nozzle is rotatable in a circumferential direction around the apex of the dome portion and can be fixed at a predetermined position.

[0057] In this case, even after the burner is installed, it can be rotated in a circumferential direction around the apex of the dome portion and can be fixed in a predetermined position, so that the position of the predetermined arrangement of fire holes (or appropriately arranged fire holes) provided in the dome portion can be adjusted.

[0058]

[14] The gas pressure welding method of the present invention, in the gas pressure welding method of

[13] above, can also include a step of adjusting each of the nozzles in a circumferential direction around the apex to (1) direct all of the flames ejected from each of the nozzles toward the press-welding surface of the pressure-welded parts, or (2) prevent the flames ejected from each of the nozzles from directing toward the press-welding surface and form a heated area of ​​a predetermined width near the press-welding surface, or (3) direct some of the flames ejected from each of the nozzles toward the press-welding surface and other flames toward the press-welding surface, or (4) direct some of the flames ejected from each of the nozzles toward the press-welding surface and other flames toward the press-welding surface, and adjust the heat intensity of each of these to heat the pressure-welded parts.

[0059] In this case, (1) by directing the entire flame jetted from each nozzle onto the pressure-welded surface of the workpiece, it is possible to use the reducing flame of acetylene gas, which is a combustible gas. (2) By preventing the flames ejected from each fire hole from hitting the pressure welding surface and forming a heated area of ​​a specified width near the pressure welding surface, it is possible to use the standard flame of propane gas, which is a flammable gas.

[0060] (3) By directing part of the flame ejected from each nozzle onto the pressure welding surface and directing other flames near the pressure welding surface, it is possible to use it with the reducing flame of acetylene gas, which is a combustible gas. (4) By directing part of the flames ejected from each nozzle onto the pressure-welding surface and directing other flames near the pressure-welding surface, and by making it possible to adjust the intensity of these flames, it is possible to use the reducing flame of acetylene gas, which is a combustible gas. [Effects of the Invention]

[0061] The present invention provides a nozzle that can prevent overheating of the nozzle during gas pressure welding of pressure-welded parts and prevent backfires from occurring inside the nozzle, as well as a heating torch and gas pressure welding method that use the same. [Brief explanation of the drawings]

[0062] [Figure 1] 1A and 1B show an embodiment of a burner according to the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a cross-sectional view. [Figure 2] 1A and 1B show another embodiment of the burner according to the present invention, in which (a) is a perspective view and (b) is a cross-sectional view. [Figure 3] 1A and 1B show a first modified example of a burner according to the present invention, in which (a) is a perspective view and (b) is a cross-sectional view. [Figure 4] 10A and 10B show a second modified example of the burner according to the present invention, in which (a) is a perspective view and (b) is a cross-sectional view. [Figure 5] This is an explanatory diagram showing how to use a fire pit with two and three approximately round fire holes. [Figure 6] This is an explanatory diagram showing how to use a fire pit with four, five, and six approximately round fire holes. [Figure 7] 10A and 10B are explanatory diagrams showing how to use a burner with slit-shaped burners provided at two and three locations. [Figure 8] FIG. 1 is an explanatory diagram showing a reference injection state of a flame from a nozzle according to the present invention. [Figure 9] 1 is a plan view illustrating a heating torch according to the present invention; [Figure 10] 1 is an explanatory view of a main part of a heating torch according to the present invention; [Figure 11] FIG. 10 is an explanatory diagram showing the state of flame ejection from a conventional nozzle, illustrating the distance between the heated press-welded member and the tip surface of the nozzle. DETAILED DESCRIPTION OF THE INVENTION

[0063] 1 to 10, an embodiment of the burner of the present invention will be described in more detail. The nozzle A2 shown in Figure 1 is made of brass and is formed as a single piece by cutting out a block of metal. Note that the nozzles A1, A2, A3, A4, A5, A6, and A7 described below are also shown in Figures 5, 6, and 7, which show the nozzles, and the nozzles are numbered in order.

[0064] The nozzle A2 has a screw portion 1 at its base that has a predetermined diameter for attachment to the mounting tube 83 (see Figure 8) of the heating torch 8, and the screw portion 1 has a slightly flattened cylindrical fitting portion 2 that fits rotatably into the mounting portion 830 of the mounting tube 83.

[0065] The insertion part 2 is provided with a slightly flattened hexagonal column-shaped operating part 3 for rotating the burner A2, and the screw part 1, insertion part 2, and operating part 3 constitute the burner base a. The operating part 3 is provided with a dome part 4 with a roughly hemispherical outer shape, and a gas guide path 5 is provided in the center of the burner base a, penetrating the burner base a and then hollowing out the interior of the dome part 4 in a roughly hemispherical shape (see Figures 1(a) and (b)).

[0066] Dome section 4 is provided with three roughly round fire holes 403, 404, and 405 that connect to gas guide path 5. Of fire holes 403, 404, and 405, fire hole 403 is provided at one vertex (reference number omitted) through which center line c of dome section 4 passes, overlapping center line c. Fire holes 404 and 405 are provided at two locations on either side of the vertex at a specified distance, with a specified opening angle facing outward.

[0067] The opening angle of the fire holes 404 and 405 is determined appropriately and is not particularly limited, but is, for example, about 70° to 80°. This opening angle also applies to the fire holes at similar locations of the other fire holes. Furthermore, this fire hole A2 and the other fire holes may be made of other types of metal, such as iron or copper. Furthermore, rather than being molded as a whole, they may be integrated by combining certain parts.

[0068] Regarding the nozzle A7 shown in FIG. 2, the explanation of the structure common to the nozzle A2 will be simplified, and each of the holes 423, 424, 425 different from the nozzle A2 will be explained in detail. A screw portion 1 is provided at the base of the nozzle A7, and a fitting portion 2 is provided in the screw portion 1.

[0069] The insertion portion 2 is provided with an operating portion 3, which is provided with a dome portion 4. Furthermore, a gas guide path 5 is provided in the center, penetrating the crater base a consisting of the screw portion 1, insertion portion 2, and operating portion 3, forming an approximately hemispherical space inside the dome portion 4 (see Figures 2(a) and (b)).

[0070] The dome section 4 is provided with three slit-shaped fire holes 423, 424, and 425 that connect to the gas guide path 5. Of the fire holes 423, 424, and 425, fire hole 423 is provided at one location where the middle part overlaps with the apex through which the center line c of the dome section 4 passes. Fire holes 424 and 425 are provided at two locations on either side of the apex, separated by a predetermined distance, so that they are parallel to each other and open outward at a predetermined angle.

[0071] The burner A8 shown in FIG. 3 is a first modified example of the burner according to the present invention. The description of the structure of the nozzle A8 that is common to the nozzle A2 will be simplified, and the dome portion 4a and each of the fire holes 426, 427, 428, 429 that are different from the nozzle A2 will be described in detail.

[0072] The base of the nozzle A8 is provided with a screw portion 1, which is provided with an insertion portion 2. An operating portion 3 is provided in the insertion portion 2, which is provided with a semi-ellipsoidal dome portion 4a that is longer than the dome portions of the other nozzles, and a gas guide path 5a is provided in the center, penetrating the nozzle base a made up of the screw portion 1, insertion portion 2, and operating portion 3, forming a roughly semi-ellipsoidal space inside the dome portion 4a (see Figures 3(a) and (b)).

[0073] Dome portion 4a is provided with four approximately round fire holes 426, 427, 428, and 429 that are connected to gas guide path 5a. Of fire holes 426, 427, 428, and 429, fire holes 426 and 427 are provided at two locations on either side of the apex of dome portion 4a, where the center line c passes, at a predetermined distance, and fire holes 428 and 429 are provided at two locations on either side of the apex of the dome portion, at an angle of 90° in the circumferential direction from the two locations, with the apex as the center, and each opening at a predetermined angle outward.

[0074] Compared to the nozzle A2, the shape of the dome portion 4a of the nozzle A8 is higher (longer) than the dome portion 4, and since the distance from the member to be pressure-welded is usually set to a fixed distance, the base of the dome portion 4a is farther away from the member to be pressure-welded, which is expected to further enhance the effect of preventing backfire during the pressure-welding work described below.

[0075] The burner A9 shown in FIG. 4 is a second modified example of the burner according to the present invention. The description of the structure of the nozzle A9 that is common to the nozzle A2 will be simplified, and the dome portion 4b and each of the fire holes 430, 431, 432, which are different from the nozzle A2, will be described in detail.

[0076] The base of the nozzle A9 is provided with a screw portion 1, and the screw portion 1 is provided with an insertion portion 2. The insertion portion 2 is provided with an operating portion 3, and the operating portion 3 is provided with a dome portion 4b that is substantially the same as that of the nozzle A2, and further, in the center, a gas guide path 5b is provided that penetrates the nozzle base a made up of the screw portion 1, insertion portion 2, and operating portion 3, and forms a substantially conical space 400 inside the nozzle base a that narrows at the top (see Figures 4(a) and (b)).

[0077] Dome portion 4b is provided with three approximately round fire holes 430, 431, and 432 connected to gas guide path 5b. Of fire holes 430, 431, and 432, fire hole 430 is formed with a slightly larger diameter than the other fire holes 431 and 432.

[0078] Fire vent 430 is located at one vertex through which the center line c of dome portion 4b passes, overlapping center line c, and is connected to the upper end of space 400. Fire vents 431 and 432 are located at two locations on either side of fire vent 430, which passes through the vertex, at a specified distance, and are opened outward at a specified angle, and are connected to the upper end of space 400 (see Figure 4(b)).

[0079] In addition to having the effect of preventing backfire during the pressure welding work described below, the nozzle A9 has an approximately conical space 400, which strengthens the flame injection force from the fire holes 430, 431, and 432, and is expected to result in more efficient heating (shortened heating time).

[0080] Here, the burners A1, A3, A4, A5, and A6 other than the burners A2, A7, A8, and A9 shown in FIGS. 1 to 3 will be briefly described. Craters A1, A3, A4, and A5 are a group of approximately round vents, similar to crane A2, and crane A6 is a group of slit vents, similar to crane A7. Note that the "approximately round shape" in this invention is not limited to a circle, but also includes, for example, an ellipse, a polygon, an irregular shape, etc.

[0081] 5(a) and (b), the burner A1 has the same screw part 1, insertion part 2, operating part 3 as the burner A2, as well as a dome part 4 and a gas guide path 5. The fire holes 401 and 402 are roughly round in shape and are provided at two points on either side of the apex of the dome part 4 at a predetermined distance, both opening outward at a predetermined angle. Moreover, the crater A2 shown in FIGS. 5(c) and 5(d) is the same as the crater A2 shown in FIG.

[0082] 6(e) and (f), the burner A3 has the same screw part 1, insertion part 2, operation part 3 as the burner A2, as well as a dome part 4 and a gas guide path 5. The four fire holes 406, 407, 408, and 409 provided in the dome part 4 are approximately round in shape.

[0083] Of these, fire holes 406 and 407 are provided at two locations on either side of the apex of dome section 4 at a predetermined distance, and fire holes 408 and 409 are provided at two locations on either side of the apex of dome section 4 at a predetermined distance, at an angle of 90° in the circumferential direction from these two locations, with the apex as the center, and both opening at a predetermined angle outward.

[0084] The nozzle A4 shown in FIGS. 6(g) and 6(h) has the same screw part 1, insertion part 2, operation part 3, dome part 4, and gas guide path 5 as the nozzle A2. The five fire holes 410, 411, 412, 413, and 414 provided in the dome portion 4 are approximately round in shape.

[0085] Of these, fire vent 410 is provided at one location at the apex of dome section 4. Fire vents 411 and 412 are provided at two locations on either side of this apex at a specified distance, and fire vents 413 and 414 are provided at two locations on either side of the apex of dome section 4 at a specified distance, at an angle of 90° in the circumferential direction from the above two locations, with the apex as the center, and both opening outward at a specified angle.

[0086] The nozzle A5 shown in FIGS. 6(i) and 6(j) has the same screw part 1, insertion part 2, operation part 3, dome part 4, and gas guide path 5 as the nozzle A2. The six fire holes 415, 416, 417, 418, 419, and 420 provided in the dome portion 4 are approximately round in shape.

[0087] Of these, fire holes 415 and 416 are provided at two locations on either side of the apex of dome portion 4 at a predetermined distance, fire holes 417 and 418 are provided at two locations on either side of the diameter line of dome portion 4 in a direction parallel to the diameter line of dome portion 4 at a predetermined distance, and fire holes 419 and 420 are both provided at a predetermined opening angle outward so that they form two rows parallel to the diameter line consisting of the three fire holes, passing through fire holes 415 and 417 and fire holes 416 and 418 respectively.

[0088] 7(a) and (b), the burner A6 has the same screw portion 1, insertion portion 2, operating portion 3 as the burner A7, as well as the dome portion 4 and gas guide path 5. The two slit-shaped fire holes 421 and 422 are provided on the dome portion 4. The fire holes 421 and 422 are provided at two locations on either side of the apex of the dome portion 4, a predetermined distance apart, in parallel, and at a predetermined angle outward. 2. The nozzle A7 shown in FIGS. 7(c) and 7(d) is the same as the nozzle A7 shown in FIG.

[0089] (action) Next, the operation of the nozzles A1, A2, A3, A4, A5, A6, and A7 will be described with reference to FIGS.

[0090] First, the heating torch 8 according to the present invention will be described with reference to FIGS. The heating torch 8 incorporating the nozzle A1 is a heating torch for gas pressure welding. The heating torch 8 has a gas inlet pipe 80 for introducing a combustible gas. A combustible gas supply pipe and an oxygen supply pipe (both not shown) having valves (not shown) are connected to the base of the gas inlet pipe 80 so that they can merge.

[0091] A U-shaped branch pipe 81 is connected to the tip of the gas inlet pipe 80, and burner pipes 82, 82, which are branch horizontal pipes, are connected to both ends of the branch pipe 81 in opposing directions. The center lines of the gas inlet pipe 80, the branch pipe 81, and the burner pipes 82, 82 are on the same plane (normally on a horizontal plane when installed).

[0092] Each of the burner tubes 82 has four nozzles A1 on the inside thereof, for a total of eight nozzles A1, which are screwed into a threaded mounting pipe 83. In this embodiment, the number of nozzles A1 is four for each burner tube 82, but this is not limited to this, and if the diameters of the pressure contact members 7a, 7b are large, a larger number can be set.

[0093] Each nozzle A1 is positioned inward (toward the center on the same plane), i.e., between the burner tubes 82, 82, and faces the press-welded members 7a, 7b (see Figures 9 and 10), and is set so that its center line is at approximately the same height as the center line of the burner tubes 82, 82 (see Figure 10).

[0094] In addition, the fire holes 401, 402 (reference numbers omitted in Figure 10) are positioned at the same height as the pressure contact surfaces 70 of the pressure contact members 7a, 7b, and above and below the fire nozzles A1 at the ends of the tips and bases of the burner tubes 82, 82, fire nozzles A1 that heat areas slightly away in the vertical direction from the pressure contact surfaces 70 of the pressure contact members 7a, 7b are angled slightly above and below the horizontal and are attached to the mounting part 830 of the mounting tube 83, facing inward like the horizontal fire nozzles A1.

[0095] This allows combustible gas to be supplied from the combustible gas supply pipe and the oxygen supply pipe to each nozzle A1 fixed to the mounting pipe 83. The combustible gas mixed with oxygen (hereinafter referred to as combustible gas) is accelerated and mixed by the spiral bodies 84 built into both ends of the branch pipe 81, supplied to each nozzle A1, and sprayed from the fire holes 401, 402 toward the press contact members 7a, 7b.

[0096] The combustible gas is then ignited, and flames are sprayed from each nozzle A1 at the same height as the burner tube 82 onto the press-contact surfaces 70 of the press-contact members 7a, 7b, and from each nozzle A1 inclined in the vertical direction, flames are sprayed toward an area slightly away from the press-contact surfaces 70 of the press-contact members 7a, 7b, thereby heating and pressing the press-contact members 7a, 7b.

[0097] The nozzle A1 used above has a dome portion 4 with an approximately partially spherical outer shape at the tip of the nozzle base a, so that the dome portion 4 can be positioned at a predetermined distance close to the pressure contact members 7a and 7b.

[0098] Since the dome portion 4 is approximately partially spherical (hemispherical), when the nozzle A1 is positioned at a predetermined distance for heating as shown in Figures 8(a), (b), and (c), the other curved portions continuing from the apex closest to the pressure contact members 7a and 7b toward the base of the dome portion become gradually farther away from the pressure contact members 7a and 7b.

[0099] This suppresses or mitigates the reflection of flames that strike the heated pressure welding members 7a, 7b during gas pressure welding and the overheating of the nozzle A1 due to the radiant heat of the heated pressure welding members 7a, 7b, compared to a conventional nozzle with a flat tip (see Figure 11).As a result, ignition of the combustible gas inside the nozzle A1 during gas pressure welding is less likely to occur, making it possible to prevent backfires.

[0100] In addition, although Figures 9 and 10 explain the basic setting and usage of the heating torch 8 using only the nozzle A1, it is also possible to use nozzles A1 to A9 individually or in combination with multiple types and carry out the method described in Figures 5 to 8.

[0101] Please refer to Figures 5(a) and (b). The nozzle A1 has fire holes 401, 402, and can be used in the following manner: (1) By preventing the flames of the fire holes 401, 402 from hitting the pressing surfaces 70 of the pressing members 7a, 7b, and by heating the vicinity of the pressing surfaces 70 to a degree that allows pressing, for example, the nozzle A1 can be used with a standard flame of propane gas, a flammable gas (see flames f2, f3 in Figures 5(a) and 8(b)).

[0102] Then, from this state, if the nozzle A1 is rotated 90° clockwise in the figure and the positions of the nozzles 401 and 402 in use mode (2) are changed so that the flames strike the pressure contact surface 70, it can be used with the reducing flame of acetylene gas, which is a combustible gas (see flame f1 in Figures 5(b) and 8(a)). The nozzle A1 can be selectively used by switching between these two patterns.

[0103] By rotating the nozzle A1 as described above, the distance of each of the fire holes 401, 402 from the pressure welding surface 70 changes, and the heat intensity on the pressure welding surface 70 can be adjusted by the angle of rotation. This makes it possible to appropriately adjust the flame according to the type of steel used, which has different resistance to rapid heating and cooling, regardless of whether the combustible gas used is acetylene gas or propane gas.

[0104] See Figures 5(c) and (d). The nozzle A2 has holes 403, 404, and 405, and can be used in the following manner: (1) the flame of the central hole 403 of the holes 403, 404, and 405 is directed toward the press-contact surface 70 of the press-contact members 7a and 7b, and the flames of the other holes 404 and 405 are directed toward the vicinity of the press-contact surface 70. In this case, it can be used with the reducing flame of acetylene gas, which is a combustible gas (see flames f1, f2, and f3 in Figures 5(c) and 8(c)).

[0105] Then, from this state, if the nozzle A2 is rotated 90° clockwise in the figure, and the positions of the nozzles 403, 404, and 405 are all set so that the flames hit the pressure contact surface 70 in use mode (2), it can be used with the reducing flame of acetylene gas, which is a combustible gas (see flame f1 in Figure 5(d) and Figure 8(a)). The nozzle A2 can be used selectively by switching between these two patterns.

[0106] Furthermore, by switching from nozzle A2 in Figure 5(d) to nozzle A2 shown in Figure 5(c), the number of flames heating the pressure welding surface 70 is reduced from three to one (f1), so the heat applied to the pressure welding surface 70 when using acetylene gas can be reduced.

[0107] In addition, the nozzle to be used may be changed depending on the steel type of the pressure welding members 7a and 7b to be welded. The steel types of pressure welding members are generally "SD345", "SD390", and "SD490" according to JIS regulations. Each has different strength (hardness), and when compared, SD345 <SD390<SD490となる。

[0108] However, as strength increases, resistance to rapid heating and cooling decreases, with the order SD345 > SD390 > SD490. In other words, if the steel type of the pressure welding parts 7a and 7b is "SD490," resistance to rapid heating and cooling is low, so for example, nozzle A1 is used in the configuration shown in Figure 5(a) and pressure welding is performed using a standard propane gas flame.

[0109] Furthermore, if the steel type of the pressure welding members 7a and 7b is "SD390," which has a medium resistance to rapid heating and cooling, then the pressure welding work can be performed using, for example, nozzle A3, in the configuration shown in Figure 6(e) below, which allows for a slightly stronger fire, and a standard propane gas flame.

[0110] Furthermore, if the steel type of the pressure welding members 7a and 7b is "SD345," it has high resistance to rapid heating and cooling, so that by using, for example, nozzle A2, the configuration shown in Figure 5(d) can be used to increase the heat, and the pressure welding work can be performed using the reducing flame of acetylene gas.

[0111] In this way, even when acetylene gas is used as the combustible gas, it is possible to adjust the heat on the press-contact surface 70 in the same way as when propane gas is used. This makes it possible to appropriately adjust the flame to accommodate the steel types of the press-contact members 7a, 7b, which have different resistance to rapid heating and cooling.

[0112] See Figures 6(e) and (f). Nozzle A3 has fire holes 406, 407, 408, and 409, and can be used in the following manner: (1) Of the fire holes 406, 407, 408, and 409, fire holes 407, 408 and 409 are arranged parallel to the pressure contact surface 70 so that the flame does not hit the pressure contact surface 70 of the pressure contact members 7a and 7b, and the vicinity of the pressure contact surface 70 can be heated within a predetermined width by fire holes 407, 408 and fire holes 406, 409, and this can be used with a standard flame for propane gas, a flammable gas (see flames f2 and f3 in Figure 6(e) and Figure 8(b)).

[0113] Then, from this state, if the nozzle A3 is rotated 45° clockwise in the figure to position each of the nozzles 406, 407 so that the flame hits the pressure contact surface 70, and the nozzles 408, 409 are positioned above and below the pressure contact surface 70 at a predetermined interval (a predetermined distance), so that the vicinity of the pressure contact surface 70 can be heated by the nozzles 408, 409 over a predetermined width, it can be used with the reducing flame of acetylene gas, a combustible gas (see flames f1, f2, f3 in Figure 6(f) and Figure 8(c)). The nozzle A3 can be used selectively by switching between these two patterns.

[0114] By rotating the nozzle A3 as described above, the distance of each of the fire holes 406, 407, 408, and 409 from the pressure welding surface 70 changes, so that the flame power on the pressure welding surface 70 can be adjusted by the angle of rotation. This makes it possible to appropriately adjust the flame according to the type of steel used, which has different resistance to rapid heating and cooling, regardless of whether the combustible gas used is acetylene gas or propane gas.

[0115] Furthermore, while the nozzles A1 and A2 require a 90° rotation to switch between the effective positions shown in Figures 5(a), (b), (c), and (d), the nozzle A3 only requires a 45° rotation. This reduces the effort required to adjust the nozzle arrangement when installing the nozzle A3. In particular, when the nozzles are screwed into the burner, adjustments cannot be made after installation, so there is an advantage in that adjustments to the rotation (angle) are easy to make during installation. The same applies to the nozzle A4, which will be described later.

[0116] See Figures 6(g) and (h).

[0117] The nozzle A4 has holes 410, 411, 412, 413, and 414, and can be used in the following manner: (1) The flame of the central hole 410 of the holes 410, 411, 412, 413, and 414 is directed toward the pressure contact surface 70 of the pressure contact members 7a and 7b, and the other holes 411, 414 and holes 412 and 413 are positioned parallel to the pressure contact surface 70, so that the vicinity of the pressure contact surface 70 can be heated within a specified width. This makes it possible to use the nozzle A4 with the reducing flame of acetylene gas, which is a combustible gas (see flames f1, f2, and f3 in Figure 6(g) and Figure 8(c)).

[0118] Then, from this state, if the nozzle A4 is rotated 45° clockwise in the figure, and the positions of the nozzles 410, 411, and 412 are all adjusted so that the flames hit the pressure contact surface 70, and the nozzles 413 and 414 are positioned above and below the pressure contact surface 70 at a predetermined interval, so that the vicinity of the pressure contact surface 70 can be heated by the nozzles 413 and 414 over a predetermined width, it can be used with the reducing flame of acetylene gas, a combustible gas (see flames f1, f2, and f3 in Figure 6(h) and Figure 8(c)). The nozzle A4 can be used selectively by switching between these two patterns.

[0119] Furthermore, by switching from nozzle A4 in Fig. 6(h) to nozzle A4 in Fig. 6(g), the number of flames on the pressure welding surface 70 decreases from three to one, so that the heat power on the pressure welding surface 70 when acetylene gas is used can be reduced, and even when acetylene gas is used as the combustible gas, it is possible to adjust the heat power on the pressure welding surface 70. This makes it possible to appropriately adjust the flame to accommodate the steel types of the pressure welding members 7a, 7b, which have different resistances to rapid heating and cooling.

[0120] See Figures 6(i) and (j). The nozzle A5 has holes 415, 416, 417, 418, 419, and 420, and can be used in the following manner: (1) Of the holes 415, 416, 417, 418, 419, and 420, the middle hole 415, 416 is arranged parallel to the pressure contact surface 70 so as to overlap it, and the other holes 417, 418 and holes 419, 420 are arranged above and below the pressure contact surface 70 at a specified interval so as not to come into contact with the pressure contact surface 70, so that the area near the pressure contact surface 70 can be heated over a specified width, making it possible to use the nozzle A5 with the reducing flame of acetylene gas, a combustible gas (see flames f1, f2, and f3 in Figure 6(i) and Figure 8(c)).

[0121] Then, from this state, by rotating nozzle A5 clockwise by 90° in the figure, use mode (2) positions each of the nozzles 415, 417, 419 and each of the nozzles 416, 418, 420 above and below the pressure contact surface 70 at a predetermined interval, allowing the vicinity of the pressure contact surface 70 to be heated over a predetermined width, making it possible to use nozzle A5 with a standard flame for propane gas, a flammable gas (see flames f2 and f3 in Figure 6(j) and Figure 8(b)). Nozzle A5 can be used selectively by switching between these two patterns.

[0122] Please refer to Figures 7(a) and (b). The nozzle A6 has fire holes 421, 422, and can be used in the following manner: (1) By preventing the flames of the slit-shaped fire holes 421, 422 from hitting the pressure contact surfaces 70 of the pressure contact members 7a, 7b and enabling the vicinity of the pressure contact surfaces 70 to be heated, the nozzle A6 can be used with a standard flame of propane gas, which is a flammable gas (see flames f2, f3 in Figures 7(a) and 8(b)).

[0123] Then, from this state, if the nozzle A6 is rotated 90° counterclockwise in the figure to position each of the nozzles 421, 422 in use mode (2) so that part of the middle of the flame hits the pressure contact surface 70 and the vicinity of the pressure contact surface 70 can be heated on both longitudinal sides of the nozzles 421, 422, it can be used with the reducing flame of acetylene gas, a combustible gas (see Figure 7(b); the flame widens vertically in Figure 8(a)). The nozzle A6 can be used selectively by switching between these two patterns.

[0124] Regardless of whether the combustible gas used is acetylene gas or propane gas, the flame power can be adjusted to accommodate the steel types of the pressure-welded parts, which have different resistance to rapid heating and cooling, in a manner similar to that of the nozzle A1.

[0125] See Figures 7(c) and (d). The nozzle A7 has fire holes 423, 424, and 425, and can be used in the following manner: (1) By directing the flame of the central fire hole 423 of the fire holes 423, 424, and 425 toward the pressure contact surface 70 of the pressure contact members 7a and 7b, and by using the flames of the other fire holes 424 and 425 to heat the vicinity of the pressure contact surface 70 within a predetermined width, the nozzle A7 can be used with the reducing flame of acetylene gas, which is a combustible gas (see Figures 7(c) and 8(c)).

[0126] Then, from this state, if the nozzle A7 is rotated 90° counterclockwise in the figure, and the positions of the nozzles 423, 424, 425 in use mode (2) are all positioned so that part of the middle part of the flame hits the pressure contact surface 70, and the vicinity of the pressure contact surface 70 can be heated, it can be used with the reducing flame of acetylene gas, which is a combustible gas (see Figure 7(d); the flame becomes wider vertically in Figure 8(a)). The nozzle A7 can be used selectively by switching between these two patterns.

[0127] Furthermore, by switching the nozzle A7 shown in Figures 7(c) and (d), in Figure 7(c), one slit-shaped flame hole 423 is positioned in the length direction relative to the pressure contact surface 70, and two fire holes 424 and 425 are positioned a predetermined distance away near the pressure contact surface 70, while in Figure 7(d), the middle parts of the fire holes 423, 424, and 425 are positioned in three places relative to the pressure contact surface 70, and both ends of the fire holes 423, 424, and 425 in the length direction are positioned near the pressure contact surface 70, making it possible to adjust the heat used to heat the pressure contact surfaces 70 of the pressure contact members 7a and 7b and their vicinity.

[0128] Furthermore, by switching from nozzle A7 in FIG. 7(d) to nozzle A7 shown in FIG. 7(c), the flames on the pressure contact surface 70 change from three short flames to one long flame, so that the flame power on the pressure contact surface 70 when using acetylene gas can be increased from minimum to maximum.

[0129] In this way, even when acetylene gas is used as the combustible gas, it is possible to adjust the flame intensity on the press-fit surfaces 70. This allows the flame to be adjusted appropriately to accommodate the steel types of the press-fit members 7a, 7b, which have different resistance to rapid heating and cooling.

[0130] As described above, the present invention can prevent overheating of the nozzles A1 to A7 during gas pressure welding of the pressure welding members 7a, 7b, and can prevent backfires from occurring inside the nozzles.

[0131] Furthermore, the positions of the fire holes relative to the pressure contact surfaces 70 of the pressure contact members 7a, 7b can be adjusted depending on the type of combustible gas, such as acetylene gas or propane gas, used at the work site. Furthermore, when the type of steel of the pressure contact members 7a, 7b is changed, for example, it is possible to provide nozzles A1 to A9 that can appropriately respond by adjusting the heat applied to the pressure contact surfaces 70 when heating the pressure contact surfaces 70 or their vicinity, depending on the characteristics of the type of steel.

[0132] The terms and expressions used in the present specification and claims are merely for explanatory purposes and are not limiting in any way, and are not intended to exclude terms and expressions equivalent to the features described in the present specification and claims and parts thereof. It goes without saying that various modifications are possible within the scope of the technical idea of ​​the present invention. [Explanation of symbols]

[0133] A2 crater a Crater base 1 Screw part 2 Inset part 3 Control section 4 Dome section 5 Gas taxiway 403, 404, 405 fire pit c Center line A7 Crater a Crater base 1 Screw part 2 Inset part 3 Control section 4 Dome section 5 Gas taxiway 423, 424, 425 fire pit A8 Crater a Crater base 1 Screw part 1 2 Inset part 2 3 Operation section 3 4a Dome section 426, 427, 428, 429 fire pit 5a Gas taxiway A9 Crater 430, 431, 432 fire pit 4b Dome section 400 space 5b Gas guideway A1 Crater 401, 402 fire pit A3 Crater 406, 407, 408, 409 fire pit A4 Crater 410, 411, 412, 413, 414 fire pit A5 Crater 415, 416, 417, 418, 419, 420 fire pit A6 Crater 421, 422 fire pit 8 Heating Torch 80 Gas 81 Branch Pipe 82 Burner tube 83 Mounting pipe 830 Mounting part

Claims

1. a crater base having a gas guide path provided therein in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The fire holes are approximately round in shape and are provided at three locations in total: one at the apex of the dome and two on either side of the apex at a predetermined distance. crater.

2. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The dome portion is rotatable in a circumferential direction around the apex thereof and is fixable at a predetermined position; The fire holes are approximately round in shape and are provided at three locations in total: one at the apex of the dome and two on either side of the apex at a predetermined distance. crater.

3. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The fire holes are approximately round and are provided at five locations in total: one at the apex of the dome, two on either side of the apex at a predetermined distance, and two on either side of the apex of the dome at a 90° angle in the circumferential direction from the first two locations, with the apex as the center. crater.

4. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The dome portion is rotatable in a circumferential direction around the apex thereof and is fixable at a predetermined position; The fire holes are approximately round and are provided at five locations in total: one at the apex of the dome, two on either side of the apex at a predetermined distance, and two on either side of the apex of the dome at a 90° angle in the circumferential direction from the first two locations, with the apex as the center. crater.

5. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The fire holes are approximately slit-shaped and are provided at two locations parallel to each other and spaced a predetermined distance apart from the apex of the dome portion when viewed in the longitudinal direction of the fire nozzle base. crater.

6. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The dome portion is rotatable in a circumferential direction around the apex thereof and is fixable at a predetermined position; The fire holes are approximately slit-shaped and are provided at two locations parallel to each other and spaced a predetermined distance apart from the apex of the dome portion when viewed in the longitudinal direction of the fire nozzle base. crater.

7. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The fire holes are approximately slit-shaped and are provided at three locations in total: one that passes through the apex of the dome portion, and two that are parallel to each other and spaced a predetermined distance apart from the apex when viewed in the longitudinal direction of the fire nozzle base. crater.

8. A crater base having a gas guide path provided inside in the longitudinal direction; a dome portion having an approximately partially spherical outer shape provided at the tip of the crater base; and a predetermined arrangement of fire holes provided through the inner and outer surfaces of the dome portion and connected to the gas guide path, The dome portion is rotatable in a circumferential direction around the apex thereof and is fixable at a predetermined position; The fire holes are approximately slit-shaped and are provided at three locations in total: one that passes through the apex of the dome portion, and two that are parallel to each other and spaced a predetermined distance apart from the apex when viewed in the longitudinal direction of the fire nozzle base. crater.

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