JP4231464B2 - Gas burner apparatus and gas pressure welding method using the same - Google Patents

Description

  The present invention relates to a gas burner apparatus and a gas pressure welding method using the gas burner apparatus, and is not particularly limited. In particular, a saturated hydrocarbon fuel gas such as methane, ethane, propane, or butane is used, such as natural gas. The present invention relates to a gas burner device suitable for performing gas pressure welding of a reinforcing bar or the like as a heating source and a gas pressure welding method using the gas burner device.

  Gas pressure welding methods are widely used to join building rebars, thick pipes, railway rails, and the like. In the gas pressure welding method, both end surfaces (for example, rebar end surfaces) to be joined to each other are ground and smoothed if necessary, then both end surfaces are butted together and fixed to a dedicated pressure jig, and the joint direction The butted portion is heated with a flame while being pressurized, and the joining end face is brought into a red hot state without melting, and is compressed and joined so that a bulging portion is formed in the joining portion.

  Conventionally, an oxygen-acetylene flame has been used as a heating source for gas pressure welding. In the pressure welding, a reducing flame is formed under a low oxygen ratio condition and heating is performed for the first time so that a good bonded surface without an oxide film remaining can be obtained on the bonded surface (adhesion surface). After heating the butting part with a reducing flame to form a red-hot contact surface, the worker increases the oxygen ratio and switches the reducing flame to a neutral flame by late heating, and then swings the heating burner left and right to widen it. Further compress while baking. As a result, a gently rounded bulge is formed at the joint, and a good joint is obtained.

  The amount of heat required varies depending on the diameter of the reinforcing bar to be pressed. In conventional gas pressure welding, the opening of the flow control valve attached to the acetylene gas flow path and the oxygen flow path is adjusted as appropriate according to the experience of the operator to obtain an optimal amount of flame (reduction flame, neutral flame). I was trying to be. The valve opening operation based on experience not only increases the burden on the operator but also inevitably causes individual differences. In order to avoid this, many gas pressure welding apparatuses that can automate gas pressure welding according to the diameter of reinforcing bars have been proposed.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 10-166163) prepares a gas flow rate numerical value numerical value program and automatically performs optimum acetylene gas flow rate control and oxygen flow rate control for each rebar diameter based on the program. An automatic gas pressure welding apparatus as described above is described. Specifically, the actual flow rate from the flow rate sensor and the set flow rate of the program are compared, and the valve opening is adjusted by the difference by the valve drive circuit.
JP-A-10-166163

  An automatic gas pressure welding apparatus constructed by using a computer program as described in Patent Document 1 performs flow control of acetylene gas and oxygen using a complicated control program and an advanced control apparatus. It is inevitable that the cost will increase. The acetylene gas flow rate control and the oxygen flow rate control are performed by a proportional circuit and a valve drive drive circuit designed for each, and even though it has a gas flow rate numerical value program by rebar diameter. For each welded bar diameter, it is not always easy to quickly and stably form a flame with an optimal oxygen ratio. The same applies to the switching between the reducing flame at the initial heating and the subsequent neutral flame, and it is difficult to say that it is a highly practical device at the construction site.

  The present invention has been made in view of the circumstances as described above, and without using a complicated control device or control program, simply using mechanical valve means, for each rebar diameter to be pressed, It is an object of the present invention to provide a gas burner device used in a gas pressure welding apparatus that can easily form a flame with an optimum heat quantity corresponding to the flame without changing the oxygen ratio. Another object of the present invention is to provide a gas pressure welding method using the gas burner device. By using the gas burner device according to the present invention, the operator can always perform the optimum gas pressure welding to the reinforcing bars having different diameters by simply operating the mechanical valve means at the construction site. The accompanying individual differences can also be eliminated.

  The present invention provides a gas pressure welding comprising a blow pipe connected to a fuel gas source and an oxygen source, a flow rate control means for controlling the flow rates of fuel gas and oxygen flowing into the blow pipe, and a ring burner disposed at the tip of the blow pipe. A gas burner device used in the apparatus, wherein the flow rate control means is capable of simultaneously switching the flow rate of the fuel gas and the flow rate of oxygen in multiple stages without changing the flow rate ratio of the fuel gas and oxygen; And a second valve means capable of switching an oxygen flow rate located in an oxygen flow path downstream of the first valve means.

  Preferably, the first valve means includes a fuel gas flow path rotary valve having a plurality of orifices having different opening degrees and an oxygen flow path rotary valve, and the two rotary valves rotate synchronously. The flow ratio of the fuel gas to oxygen passing through the orifice of the rotary valve for the fuel gas flow path and the orifice of the rotary valve for the oxygen flow path is the same for all orifice pairs. It is said that.

  In the gas burner device according to the present invention, in the first valve means, the optimum fuel gas flow rate, oxygen flow rate and flow rate ratio for each rebar diameter obtained from the experience so far are obtained at each rebar diameter. Correspondingly, the opening of the fuel gas channel and the opening of the oxygen channel are set in advance, and they can be switched simultaneously in pairs. Therefore, the operator can obtain the optimum heating condition at the construction site simply by selecting the corresponding flow path in the first valve means corresponding to the diameter of the reinforcing bar to be gas pressure welded. it can.

  In the middle of the work, when the reinforcing bars of different diameters are gas-welded, the ring burner is replaced with one corresponding to the reinforcing bars of the diameters, and the first valve means is operated to change the first corresponding to the diameter. Another flow path in the valve means is selected by operating a dial or the like. Thereby, the optimal fuel gas flow rate and oxygen flow rate corresponding to the reinforcing bar can be obtained at the same flow rate ratio. This operation is simply a valve operation mechanically and is very easy.

  In the initial heating stage, the operator selectively operates the second valve means to reduce the oxygen flow rate so that a reducing flame is formed. At the end of the initial heating stage, the second valve means is selectively operated again to restore the oxygen flow to the neutral flame, and heating is continued. This operation is also very easy because it merely mechanically operates the valve. The second valve means is also of a type having a large number of openings corresponding to the diameter of each reinforcing bar, so that the controllability is further improved.

  The gas burner apparatus used in the gas pressure welding apparatus according to the present invention can be suitably used even when the fuel gas is acetylene gas. However, acetylene gas is expensive, has high risk and requires careful handling, and acetylene flames are prone to backfire, especially in the case of neutral flames used in later heating. For this reason, in gas pressure welding, it has been studied to use a saturated hydrocarbon fuel gas such as compressed natural gas (CNG) instead of acetylene gas. Has gained a lot of knowledge.

  That is, the present inventors conducted an experiment in which the end surfaces of the reinforcing bars were gas-welded with each other particularly using CNG as a saturated hydrocarbon fuel gas, the oxygen ratio of the premixed gas, the shape of the flame, the flame hole load of the crater, By performing various changes, when performing gas pressure welding using a saturated hydrocarbon gas-oxygen flame, the oxygen ratio of the burner flame is set within a range of 0.43 to 0.58, and the burner flame By maintaining the separation distance between the tip and the joint in the previous period until the joint contact, combustion stability and reduction sufficient for pressure welding can be obtained, and bending strength equivalent to that of pressure welding with acetylene flame can be obtained. Knowing that the provided joint can be obtained, a patent application has already been filed (Japanese Patent Application No. 2004-016026). If the oxygen ratio of the heating burner flame is out of the range of 0.43 to 0.58, the oxide film area on the bonding surface becomes large, or the bonding temperature rises excessively, causing burning cracks, etc. Good pressure welding is not possible.

  Therefore, when performing gas pressure welding using a saturated hydrocarbon-based gas-oxygen flame, it is required to strictly maintain the oxygen ratio in the burner flame more than the gas pressure welding in the acetylene flame. As described above, the gas burner apparatus according to the present invention is a mechanically operated first and second valve means, so that a reducing flame having an oxygen ratio as set for a plurality of different reinforcing bar diameters. This is particularly effective in a gas pressure welding apparatus using a saturated hydrocarbon gas as a fuel gas.

  According to the present invention, the operator operates the mechanical valve means at the construction site and simply switches the flow path to obtain the optimum flame state necessary for gas pressure welding even for reinforcing bars having different diameters. And individual differences associated with experience can be easily resolved. Further, since the gas burner device does not require a complicated control program or control device, the gas burner device is inexpensive and rich in work on site.

  In particular, the gas burner apparatus used in the gas pressure welding apparatus according to the present invention can easily and accurately adjust the flow rate ratio between the fuel gas and oxygen. Therefore, in the gas pressure welding apparatus using a saturated hydrocarbon gas as the fuel gas. Effectively used.

  Hereinafter, the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a schematic view of an apparatus for carrying out the gas pressure welding method according to the present invention. FIG. 2 is a cross-sectional view showing an example of the first valve means used therein, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing an example of the second valve means, and FIG. 5 is a cross-sectional view taken along the line VV of FIG.

  In FIG. 1, reference numeral 10 denotes a blow tube, and a ring burner 20 is attached to the tip of the blow tube in a replaceable manner. The blow pipe 10 has a fuel gas inlet 11 and an oxygen inlet 12, and valves 11a and 12a for switching the flow rate ON / OFF are provided. The two valves 11a and 12a are actuated simultaneously by an up and down handle 13, and when the handle 13 is slightly moved from the fully closed state, the valve 11a on the fuel gas flow path side is first opened slightly, and the ring burner Ignition at 20 is possible. By further operating the handle 13 after ignition, the two valves 11a and 12a are fully opened.

  Two fixed jigs 21a and 21b (only one fixed jig 21a is shown in FIG. 1) are attached to the blowing tube 10 at symmetrical positions with the blowing tube 10 in between, and a presser bar 22 opened in a V shape. Is positioned in the axial direction so that is located at the center of the ring burner 20. The gas pressure welding operation can be stably performed by holding the blowing tube 10 in such a manner that the presser bar 22 is pressed against the reinforcing bar at the time of the gas pressure welding operation, particularly at the intended heating.

  A fuel gas inlet 11 of the blow pipe 10 is connected to a fuel gas source (CNG cylinder 1 in the illustrated example), and an oxygen inlet 12 is connected to an oxygen source (oxygen cylinder 2). Below, the connection aspect is demonstrated. CNG is one example of the fuel gas to be used, and acetylene gas and other hydrocarbon fuels can be similarly used as the fuel gas.

  A flow rate control box 30 is located between the blow pipe 10 and each of the cylinders 1 and 2. In the control box 30, CNG adjusted to, for example, 0.3 MPa by the CNG primary pressure reducing valve 3 is supplied to the first gas hose 5. In addition, oxygen adjusted to 0.8 MPa, for example, by the oxygen primary pressure reducing valve 4 passes through the first oxygen hose 6 and flows in. In addition, 5a is a backfire prevention tool.

  The flow control box 30 includes primary pressure indicators 31 and 32 for CNG and oxygen, secondary pressure regulating valves (not shown) for each, and secondary pressure indicators 33 and 34, and CNGs whose pressures are adjusted. A first valve means 40 (see FIGS. 2 and 3) that can change the flow rate of both oxygen in multiple stages without changing the oxygen ratio is housed. In this example, the CNG secondary adjustment pressure is 0.15 MPa, and the oxygen secondary adjustment pressure is 0.6 MPa.

  The first valve means 40 will be described. The first valve means 40 has a casing 41 with a rotating shaft 42. The casing 41 is fixed to the flow rate control box 30 with screws 43, and a dial 35 is fixed to a portion extending to the outside of the rotating shaft. The casing 41 is divided into three parts (41a, 41b, 41c) in the axial direction, and a first recess 44a is formed on the inner surface side of the first member 41a on the left side in the drawing. A first disk 50 that functions as a rotary valve so as to rotate integrally with the rotary shaft 42 is fitted into the first recessed portion 44a.

  The first disk 50 is formed with six holes 51... Extending radially at equal intervals in the circumferential direction, and a portion slightly above the lower end of each hole 51 is on the left side in the drawing of the first disk 50. The first passage 52 is open to the outer surface side which is a surface. The vicinity of the lower end of each hole 51 communicates with a second passage 53 that opens to the inner surface side (right side in the drawing) of the first disk 50. In FIG. 3, four of the six holes 51 are shown as a whole for ease of illustration, and two of them show only the vicinity of the lower end.

  The first member 41a of the casing 41 is formed with one oxygen inflow path 61 connected to the first oxygen hose 6 via a coupler, and the lower end of the oxygen inflow path 61 is formed in the first disk 50. It is an open end 62 that opens to the bottom surface of the first recessed portion 44 a so as to face the rotation path of the first passage 52.

  A spindle 54 is rotatably screwed into each hole 51 formed in the first disk 50, and the tip of the spindle 54 is tapered. The spindle 54 advances and retreats in the hole 51 by rotating, and the degree of opening of the first passage 52 (orifice opening degree) changes depending on the position of the tip.

  Six depressions 55 are provided on the outer side surface (left side surface in the figure) of the first disk 50 at equal intervals in the circumferential direction, and an appropriate pressing member 63 provided on the first member 41a of the casing 41 is provided with The hollow 55 is press-fitted by a spring (not shown).

  The 2nd member 41b of the casing 41 has the oxygen outflow path 65 in the position facing the oxygen inflow path 61 formed in the 1st member 41a. The inflow side open end 66 of the oxygen outflow path 65 is provided at a position facing the open end 62 of the oxygen inflow path 61, and a part of the inflow side open end 66 is rotated by the second passage 53 of the hole 51. It is supposed to be located on the trajectory. The outflow side open end of the oxygen outflow path 65 is open to the outer peripheral portion of the second member 41b, and is connected to the second oxygen hose 8 via the output coupler 7 (see FIG. 1). The second member 41b of the casing 41 further has a CNG outflow path 75, the outflow side open end of which is open to the outer peripheral portion of the second member 61b, and the second gas hose via the output coupler 7. 9 is connected.

  The third member 41c of the casing 41 has substantially the same structure as the first member 41a described above, and has a second recessed portion 44c on the inner surface side. Then, a second disk 50c having the same structure as the first disk 50, which also functions as a rotary valve, is fitted therein so as to rotate in an integrated manner with the rotating shaft 42 in an inverted state. Yes. The second disk 50c has the same structure as the first disk 50, and members having the same functions are denoted by the same reference numerals as those of the first disk 50, and detailed description thereof is omitted.

  The third member 41 c has a CNG inflow passage 71 formed in the same manner as the oxygen inflow passage 61, and its outflow side open end 76 is the same as that of the oxygen inflow passage 61 in the second recessed portion. It opens to the bottom of 44c. In addition, the inflow end opening 76 of the CNG outflow path 75 is provided at a position facing the open end 76 of the CNG inflow path 71, similar to the inflow side open end 66 of the oxygen outflow path 65, and A part of the inflow side open end 76 is positioned on the rotation locus of the second passage 53 of the hole 51.

  When any one of the six holes 51 formed in the first disk 50 is located between the oxygen inflow path 61 and the oxygen outflow path 65, at the same time, the six holes 51 formed in the second disk 50c The position of each flow path is set so that any one of the positions is sandwiched between the CNG inflow path 71 and the CNG outflow path 75. Further, the first disk 50 and the second disk 50c rotate at the same time when the rotary shaft 42 is rotated with the dial 35, and while the rotary shaft 42 rotates 360 degrees, The formed six holes 51 and the six holes 51 formed in the second disk 50c are in a synchronized state, one at a position sandwiched between the oxygen inflow path 61 and the oxygen outflow path 65, and the other They move to positions sandwiched between the CNG inflow path 71 and the CNG outflow path 75, respectively.

  The positions of the spindles 54, 54 of each pair of holes 51, 51 are adjusted by screw rotation so that the respective opening (orifice opening) can be obtained so that CNG and oxygen with a desired flow rate ratio can be obtained. Set. Further, the positions of the spindles 54 and 54 are adjusted so that the total flow rates are different in the holes 51 and 51 that form the six orifice pairs while maintaining the same flow rate ratio. By setting in this way, the operator can switch the flow rates of CNG and oxygen with different flow rates in six stages while the oxygen ratio is the same by simply rotating the dial 35 to a predetermined position.

  In actual gas pressure welding, the spindle positions (orifice opening degrees) of the six holes 51 to be paired are set in advance so that flow rates corresponding to six types of reinforcing bar diameters can be obtained, and as shown in FIG. The operation of the operator is further simplified by providing the dial 35 with a corresponding reinforcing bar diameter display (for example, P8, P12, P14...).

  The oxygen and CNG selected for the appropriate oxygen ratio and flow rate in the flow rate control box 30 as described above flow into the blow pipe 10 through the second oxygen hose 8 and the second CNG hose 9. In the burner device of the present invention, the second valve means 100 is disposed in the second oxygen hose 8 as means for switching the burner flame between the reducing flame and the neutral flame.

  As shown in FIGS. 4 and 5, the second valve means 100 has a support shaft 102 fixedly erected on a base material 101, and 6 is arranged on the support shaft 102 at equal intervals in the circumferential direction. A dial member 104 having two screw holes 103 is inserted while being urged outward (right side in the figure) by a spring 105. Two through holes 106 are formed in the dial member 104 so as to face each other, and a ball 107 enters the through hole 106 while being biased by a spring. The support shaft 102 is provided with six concave grooves 108 extending in the axial direction so that the balls 107 urged by the springs enter the concave grooves 108.

  An oblique groove 109 having a predetermined length is cut at the distal end side of the support shaft 102, and a handle 111 having a rod tip screw 110 having the distal end inserted into the oblique groove 109 is inserted into the distal end of the support shaft 102. . A thrust bearing 112 is interposed between the back surface of the handle 111 and the surface of the dial member 104. In addition, rod tip screws 113 are screwed into the six screw holes 103 formed in the dial member 104, and the tip positions of the rod tip screws 113 are adjusted according to the screwing amount.

  A valve main body 120 is fixed to the base material 101, a second oxygen hose 8 is connected to one end 121 thereof, and a third oxygen hose 8 a is connected to the other end 122. In the third oxygen hose 8 a, the blow tube 10 is connected to the oxygen inlet 12. A valve seat 125 is provided between the oxygen inflow portion 123 and the oxygen outflow portion 124 of the valve body 120, and a spindle 130 having a tapered tip is inserted therein.

  The spindle 130 has a flange 131, and a spring 132 is interposed between the valve seat 125 and the flange 131, so that the spindle 130 is always urged outward, that is, in a direction in which the valve is opened. The flange 131 is in contact with the base body 101 of the valve main body 120 so that the valve is positioned in the valve opening direction, and the other end of the spindle 130 does not jump from the base body 101 of the valve main body 120 when positioned on the outermost side. The length is set. Further, both positions are set so that the shaft center line of the spindle 130 and the shaft center lines of the rod end screw 113 screwed into the six screw holes 103 formed in the dial member 104 can be at the same position. Has been.

  In the above configuration, when the operator rotates the dial member 104, the ball 107 enters one of the six concave grooves 108 formed in the support shaft 102 and extending in the axial direction. Positioned temporarily. The position is a position where the axial center line of the spindle 130 described above coincides with the axial center line of any of the rod end screws 113 screwed into the six screw holes 103 formed in the dial member 104. Then, when the operator further rotates the dial member 104 against the urging force, it becomes possible for all of the six rod end screws 113 to take positions that coincide with the axis of the pindle 130.

  When the handle 111 is rotated at any positioning position, the handle 111 moves inward (left side in the drawing) along the locus of the oblique groove 109, and the movement is transmitted to the dial member 104 via the thrust bearing 112. . As a result, the dial member 104 is also moved inward (left side in the figure), and by this movement, the tip of the rod end screw 113 comes into contact with the other end of the spindle 130, and the valve closes the spindle 130 (leftward in the figure). ).

  The moving distance in the axial direction of the dial member 104 is regulated by the effective length in the axial direction of the oblique groove 109, and the oblique groove 109 has a horizontal end (not shown) at the end portion, When the tip of 110 enters the horizontal groove, the movement of the dial member 104 (and the handle 111) in the axial direction stops. Further, depending on how far the tips of the six rod tip screws 113 are initially advanced toward the spindle 130, the opening degree of the spindle 130 when the dial member 104 has advanced by the same distance is determined as each rod tip screw 113. Can be changed every time.

  As described above, the first valve means 40 rotates the dial 35 to supply oxygen and CNG at six different flow rates to the second oxygen hose 8 while maintaining the same oxygen ratio (flow rate ratio). And poured into the second CNG hose 9. The six rod end screws 113 of the second valve means 100 correspond to the six stages of oxygen flow rate of the first valve means 40, respectively, and when the spindle 130 is in the most closed position, the oxygen flow rate becomes 0.8. The delivery amount of the tip of each rod tip screw 113 is set so as to narrow down to the extent. Then, as shown in FIG. 1, the dial member 104 displays the corresponding reinforcing bar diameter (for example, P8, P12, P14 ..) has been made.

  At the time of gas pressure welding, a ring burner 20 corresponding to the diameter of the reinforcing bar to be pressure welded is selected and attached to the blow tube 10. Accordingly, the dial 35 of the first valve means 40 is rotated and set, for example, at the position P12. At the same time, the dial member 104 of the second valve means 100 is rotated and set to the corresponding position P12, and the handle 111 is operated to place the spindle 130 in the position where the flow path is narrowed (advanced position).

  After the fixed jigs 21a and 21b are set at appropriate positions, the pressure reducing valves 3 and 4 are adjusted, and oxygen and CNG reduced to a predetermined pressure are sent into the control box 30. The handle 13 is slightly opened and a small amount of CNG is sent to the ring burner 20 to ignite. After the flame is stabilized, the handle 13 is fully opened. Thereby, for example, oxygen and CNG having a flow rate corresponding to the diameter of the reinforcing bar of P12 are sent to the ring burner 20 at an oxygen ratio set in advance by the first valve means 40.

  On the way, oxygen passes through the second valve means 100. Therefore, since the oxygen flow rate is reduced, the flame in the ring burner 20 becomes a reducing flame. A so-called initial heating proceeds while the joining surface of the reinforcing bars held in a posture in which the tips are brought into contact with each other by a conventionally known pressure welding apparatus is heated by the reducing flame described above. When the initial heating is completed, the operator operates (rotates) the handle 111 of the second valve means 100 to bring the spindle 130 to the most open position. Thereby, the oxygen flow rate returns to the flow rate set in advance by the first valve means 40, and the flame becomes a neutral flame. Hereinafter, heating with a neutral flame is continued until pressure welding is obtained. If necessary, the two fixing jigs 21a and 21b described above are retracted to release the contact with the reinforcing bars, and then baking is performed.

  In the course of work, when it is necessary to perform pressure welding of reinforcing bars having different diameters (for example, P14 reinforcing bars), the operator replaces the ring burner 20 with one adapted to P14, and the first valve means 40. The dial 35 and the dial member 104 of the second valve means 100 are both rotated to the position P14. Thereby, the flow rate of CNG and oxygen optimum for the rebar diameter of P14 can be obtained without changing the oxygen ratio. In this state, by operating the second valve means 100 handle 111 in the same manner as described above, the P14 rebar is also subjected to initial heating with a reducing flame and subsequent heating with a neutral flame. Can do.

  These operations are merely an operation in which the operator manually switches the mechanical valve means. The operation itself is very simple, and the gas burner device itself can be manufactured at low cost. In addition, since the flow rate of fuel gas (CNG in the above example is the same as acetylene gas as described above) and oxygen is set according to the preset opening of the spindle, the total flow rate and the flow rate ratio are set. Can be carried out easily and precisely.

  In the above apparatus, the first valve means 40 uses the first disk 50 and the second disk 50c having the six holes 51 so that the six types of reinforcing bar diameters can be quickly handled. The number of the holes 51 to be set is a design matter that is appropriately set according to the type of reinforcing bar diameter that requires gas pressure welding. Naturally, the number of rod end screws 113 of the second valve member 100 also changes accordingly.

  Further, the casing 41 is composed of three members 41a, 41b, and 41c, and the second member 41b is formed with the outflow passages 65 and 75 for both oxygen and CNG, but this reduces the overall size. For this reason, the casing 41 may be constituted by four members, and the oxygen outflow passage 65 and the CNG outflow passage 75 may be formed in each casing member. Furthermore, as described above, when using acetylene gas as the fuel gas, it goes without saying that the same burner device can be used as it is.

  In the gas burner apparatus according to the present invention, since the flow rate setting of the fuel gas (CNG) and oxygen depends on the preset opening of the spindle, the setting of the total flow rate and the flow rate ratio can be easily and precisely performed. It is particularly effective to use the gas burner device according to the present invention in a gas pressure welding method using a saturated hydrocarbon gas as a fuel gas as described in Japanese Patent Application No. 2004-016026 already filed by the present inventors. Become.

The schematic diagram of the apparatus for enforcing the gas pressure welding method by this invention. Sectional drawing which shows an example of the 1st valve | bulb means used with the apparatus of FIG. Sectional drawing by the III-III line of FIG. Sectional drawing which shows an example of the 2nd valve means used with the apparatus of FIG. Sectional drawing by the VV line | wire of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Blow pipe, 20 ... Ring burner, 21 ... Fixed jig, 22 ... Holding rod, 30 ... Control box, 31-34 ... Pressure indicator, 35 ... Dial, 40 ... First valve means, 42 ... Rotating shaft, 41 ... Casing 50 ... first disc 50c ... second disc 51 ... hole 54 ... spindle 61 ... oxygen inflow path 65 ... oxygen outflow path 71 ... CNG inflow path 75 ... CNG outflow path 100 ... second Valve means, 102 ... spindle, 103 ... screw hole, 104 ... dial member, 108 ... concave groove extending in the axial direction of the spindle, 109 ... diagonal groove, 110 ... rod end screw, 111 ... handle, 112 ... thrust bearing, 113 ... Rod end screw, 120 ... Valve body, 125 ... Valve seat, 130 ... Spindle, 132 ... Spring

Claims (4)

A gas used in a gas pressure welding apparatus comprising a blow pipe connected to a fuel gas source and an oxygen source, a flow rate control means for controlling the flow rates of fuel gas and oxygen flowing into the blow pipe, and a ring burner disposed at the tip of the blow pipe A burner device,
The flow rate control means includes a first valve means capable of simultaneously switching the flow rate of the fuel gas and the flow rate of oxygen without changing the flow rate ratio between the fuel gas and oxygen, and an oxygen flow downstream from the first valve means. A gas burner device comprising: a second valve means that is located in the path and can switch an oxygen flow rate.   The first valve means includes a fuel gas flow path rotary valve having a plurality of orifices with different opening degrees and an oxygen flow path rotary valve so that the two rotary valves rotate in synchronization. The flow rate ratio of fuel gas to oxygen passing through the orifice of the rotary valve for the fuel gas flow path and the orifice of the rotary valve for the oxygen flow path is the same for all orifice pairs. The gas burner device according to claim 1, wherein   A gas pressure welding method for a reinforcing bar or the like using the gas burner device according to claim 1 or 2, wherein the first valve means is switched so as to obtain fuel gas and oxygen at a flow rate suitable for the size of the reinforcing bar or the like to be pressed. When the previous heating stage is completed by switching the oxygen flow rate ratio of the second valve means so that a reducing flame can be obtained from the ring burner in the previous heating stage until the joints are brought together. In the gas pressure welding method, the subsequent heating is performed by switching the oxygen flow rate ratio of the second valve means so as to obtain a neutral flame.   The gas pressure welding method according to claim 3, wherein the fuel gas is acetylene gas or saturated hydrocarbon gas.

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