JP7257095B1 - Blowpipe and gas cutting method - Google Patents

Abstract

An object of the present invention is to provide a blowpipe capable of reducing the amount of CO2 generated when an object is fused using combustible gas. A blowpipe according to one aspect of the present invention is a blowpipe for fusing an object using a combustible gas containing hydrogen, the blowpipe being arranged so as to surround a central outlet and the central outlet. A crater having a plurality of peripheral discharge ports, a preheating gas pipe that supplies a mixed gas of combustible gas and preheating oxygen gas to the peripheral discharge port, and a fusing gas pipe that supplies fusing oxygen gas to the central discharge port. a first valve for controlling the flow rate of the mixed gas flowing through the preheating gas pipe; and a second valve for controlling the flow rate of the fusing oxygen gas flowing through the fusing gas pipe, wherein the first valve is provided with at least the mixed gas and a first opening with a second flow rate smaller than the flow rate of the first opening. It is configured to be able to cut off gas. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a blowpipe and a gas fusion cutting method.

A gas fusion cutting method for cutting an object by using a combustible gas is known. In this gas fusion cutting method, a mixed gas in which combustible gas is mixed with oxygen gas is burned, and the object is preheated with the heat. Then, when the object is sufficiently preheated, the oxygen gas for fusing is further supplied, and the object is fused while being oxidized.

As the combustible gas, a combustible gas containing 38% by volume or more and 45% by volume or less of ethylene, the balance being hydrogen and unavoidable impurities has been proposed (see Japanese Patent No. 4848060). It is said that this combustible gas is easy to store, transport, etc., and can contribute to the improvement of the quality of the finished state after gas cutting.

Japanese Patent No. 4848060

There is a strong demand for reduction of CO ₂ gas due to recent environmental problems, and the less the hydrocarbon gas that can be the source of CO ₂ in the combustible gas, the better. However, hydrocarbon gas is a calorie source in the combustible gas, that is, it contributes to thermal power, and reducing this tends to lengthen the time required for fusing. Since the amount of CO ₂ generated is determined by the concentration of hydrocarbon gas contained in the combustible gas times the fusing time, simply reducing the concentration of hydrocarbon gas does not sufficiently reduce the amount of CO ₂ generated.

The present invention has been made based on the above circumstances, and provides a blowpipe capable of reducing the amount of _CO2 generated when an object is fused using a combustible gas, and a gas fusion cutting method using this blowpipe. for the purpose of providing

A blowpipe according to an aspect of the present invention is a blowpipe for blowing an object using a combustible gas containing hydrogen, and comprises a central outlet and a plurality of peripheral edges arranged to surround the central outlet. a preheating gas pipe that supplies a mixed gas of the combustible gas and the preheating oxygen gas to the peripheral outlet; and a fusing gas pipe that supplies the fusing oxygen gas to the central outlet. a first valve for controlling the flow rate of the mixed gas flowing through the preheating gas pipe; and a second valve for controlling the flow rate of the fusing oxygen gas flowing through the fusing gas pipe, wherein the first valve is controllable to at least a first opening that sets the flow rate of the mixed gas as a first flow rate, and a first opening that sets a second flow rate that is less than the flow rate of the first opening, and Two valves are configured to be able to cut off at least the oxygen gas for fusing.

In the blowpipe, the first valve can be controlled between a first opening with a large flow rate of the mixed gas of the combustible gas and the preheating oxygen gas and a second opening with a low flow rate. The flow rate of the mixed gas can be reduced as the second degree of opening. During fusing, it is sufficient to maintain the state in which the object is oxidized by the oxygen gas for fusing, so high calorie is not required in the combustible gas, and even if the amount of hydrocarbon gas is reduced or eliminated, the increase in fusing time is suppressed. can. On the other hand, in the blowpipe, even if the amount of hydrocarbon gas is reduced or set to zero, the flow rate of the mixed gas can be increased by setting the opening to the first opening during preheating, and the calories required for preheating can be secured. An increase in time can also be suppressed. Therefore, by using the blowpipe, it is possible to reduce the hydrocarbon gas concentration while maintaining the fusing time in the amount of CO ₂ generated determined by the hydrocarbon gas concentration x fusing time contained in the combustible gas. A blowpipe can reduce the amount of _CO2 generated.

Preferably, the first valve and the second valve are independently controllable. By making the first valve and the second valve independently controllable in this way, the intensity of the flame can be freely controlled according to the state of fusing, thereby further suppressing an increase in the fusing time.

A combustible gas inlet for taking in the combustible gas from the outside, an oxygen gas inlet for taking in oxygen gas from the outside, and the combustible gas being supplied from the combustible gas inlet to the preheating gas pipe. a combustible gas pipe, an oxygen gas pipe for supplying the oxygen gas from the oxygen gas inlet to the preheating gas pipe and the fusing gas pipe, and the combustible gas supplied to the preheating gas pipe It is preferable to further include a third valve for controlling the flow rate of gas, and a fourth valve for controlling the flow rate of the oxygen gas supplied to the preheating gas pipe. By constructing the blowpipe in this way, the mixed gas can be adjusted inside the blowpipe, so that the welding operator can easily adjust the flame at hand. Further, if two gas cylinders or gas tanks for oxygen gas and combustible gas are prepared, the blowpipe can be used, so that the fusing equipment as a whole can be constructed simply.

A gas fusion cutting method according to another aspect of the present invention is a gas fusion cutting method for cutting an object using a combustible gas containing hydrogen, wherein the blowpipe of the present invention is used, and the first valve is opened in the first opening. a flame forming step of forming a flame while blocking the oxygen gas for fusing by the second valve; a preheating step of preheating the object with the flame formed in the flame forming step; a flow control step of setting the first valve to the second opening; and a fusing step of fusing the object while supplying the fusing oxygen gas after the preheating step.

In the gas cutting method, the blowpipe of the present invention is used, the flow rate of the mixed gas is increased during preheating, and the flow rate of the mixed gas is decreased during cutting. For this reason, in the amount of CO ₂ generated determined by the hydrocarbon gas concentration contained in the combustible gas x the fusing time, the hydrocarbon gas concentration can be reduced while maintaining the fusing time, so the gas fusing method can be used. can reduce the amount of _CO2 generated.

The combustible gas preferably contains ethylene. By using the combustible gas containing ethylene as described above, the amount of CO ₂ generated can be reduced, and the quality of the finished state after gas fusing can be improved.

The blowpipe of the present invention can reduce the amount of CO ₂ generated when an object is fused using combustible gas. In addition, the gas fusion cutting method of the present invention can reduce the amount of CO ₂ generated by using this blowpipe.

FIG. 1 is a schematic cross-sectional view showing the configuration of a blowpipe according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of piping of the blowpipe of FIG. 3 is a schematic plan view showing the configuration of the tip of the blowpipe of FIG. 1. FIG. FIG. 4 is a flowchart showing a gas fusion cutting method according to one embodiment of the present invention. FIG. 5 is a schematic side view showing the configuration of a blowpipe according to an embodiment different from that of FIG. 1 of the present invention. FIG. 6 is a schematic diagram showing the configuration of the piping of the blowpipe of FIG.

[First embodiment]
Hereinafter, a blowpipe and a gas fusion cutting method according to a first embodiment of the present invention will be described with appropriate reference to the drawings.

[Blowpipe]
A blowpipe 1 shown in FIGS. 1 and 2 is a blowpipe for melting and cutting an object using a combustible gas containing hydrogen. The blowpipe 1 includes a crater 10, a combustible gas inlet 21, an oxygen gas inlet 22, a combustible gas pipe 31, an oxygen gas pipe 32, a preheating gas pipe 33, and a fusing gas pipe. 34 , a first valve 41 , a second valve 42 , a third valve 43 and a fourth valve 44 .

The object is a material that can be fused by flame, in other words, a metal material that is oxidized by being exposed to oxygen at a high temperature. Steel materials, titanium materials, etc. can be mentioned as the above-mentioned object.

<crater>
As shown in FIG. 3, the crater 10 has a central outlet 10a and a plurality of peripheral outlets 10b arranged to surround the central outlet 10a.

Specifically, as shown in FIG. 3, the crater 10 is composed of the tip surfaces of an outer cylinder 11 and an inner cylinder 12 that are coaxially arranged. It is covered with a lid portion 13 . The central discharge port 10 a is formed by the outlet of the inner cylinder 12 , and the plurality of peripheral discharge ports 10 b are formed by through holes formed in the lid portion 13 .

In addition, the inner cylinder 12 constitutes a portion (end portion) of the preheating gas pipe 33 , and the outer cylinder 11 constitutes a portion (end portion) of the fusing gas pipe 34 . That is, as will be described later, the oxygen gas for fusing is discharged from the central discharge port 10a, and the mixed gas is discharged from the peripheral discharge port 10b.

<Inlet>
The combustible gas inlet 21 is an inlet for taking in the combustible gas from the outside. Also, the oxygen gas inlet 22 is an inlet for taking in oxygen gas from the outside.

<Piping>
The combustible gas pipe 31 supplies the combustible gas from the combustible gas inlet 21 to the preheating gas pipe 33 . That is, the combustible gas pipe 31 is connected to the combustible gas inlet 21 and the preheating gas pipe 33 .

The oxygen gas pipe 32 supplies the oxygen gas from the oxygen gas inlet 22 to the preheating gas pipe 33 and the fusing gas pipe 34 . That is, the oxygen gas pipe 32 is connected to the oxygen gas inlet 22 and the preheating gas pipe 33 , and is also connected to the oxygen gas inlet 22 and the fusing gas pipe 34 . The oxygen gas pipe 32 may be connected from the oxygen gas inlet 22 to the preheating gas pipe 33 and the fusing gas pipe 34 by different pipes, but as shown in FIG. may have been

The preheating gas pipe 33 supplies the mixed gas of the combustible gas and the oxygen gas for preheating to the peripheral discharge port 10b. In the blowpipe 1 , the combustible gas is supplied from the combustible gas pipe 31 . The oxygen gas for preheating is supplied from the oxygen gas pipe 32 . These gases are mixed in the preheating gas pipe 33 and supplied to the peripheral discharge port 10b.

The fusing gas pipe 34 supplies oxygen gas for fusing to the central discharge port 10a. The oxygen gas for fusing is supplied from the oxygen gas pipe 32 .

<First valve>
The first valve 41 is arranged in the preheating gas pipe 33 . More specifically, the arrangement position of the first valve 41 is downstream of the position where the combustible gas pipe 31 and the oxygen gas pipe 32 merge, and upstream of the peripheral discharge port 10b. .

The first valve 41 controls the flow rate of the mixed gas flowing through the preheating gas pipe 33 . The first valve 41 is controllable to at least a first degree of opening that sets the flow rate of the mixed gas as the first flow rate, and a second degree of opening that sets the flow rate of the mixed gas to a second flow rate that is less than the flow rate of the first degree of opening. be.

The first valve 41 may be composed of a switching valve that switches between the first flow rate and the second flow rate, or may be composed of a flow rate variable valve that can steplessly switch the flow rate. When the first valve 41 is configured as a switching valve, it is possible to quickly and stably switch between the first degree of opening and the second degree of opening. On the other hand, when the first valve 41 is configured with a variable flow rate valve, fine adjustment of the first opening and the second opening can be performed according to the type of object and environmental conditions, so the fusing conditions can be optimized. easy to convert.

The lower limit of the ratio (flow ratio) of the flow rate (L/min) at the first opening to the flow rate (L/min) at the second opening is preferably 1.2, more preferably 1.5. On the other hand, the upper limit of the flow rate ratio is preferably 3, more preferably 2.5. If the flow rate ratio is less than the lower limit, the effect of shortening the preheating time of the object may be insufficient. Conversely, if the flow rate ratio exceeds the upper limit, the amount of CO ₂ generated may not be sufficiently reduced.

<Second valve>
The second valve 42 is arranged in the fusing gas pipe 34 .

The second valve 42 controls the flow rate of the fusing oxygen gas flowing through the fusing gas pipe 34 . The second valve 42 is configured to block at least the oxygen gas for fusing. The second valve 42 may be configured by a switching valve that turns ON/OFF the flow of the fusing oxygen gas, but is preferably configured by a flow rate variable valve capable of setting the flow rate to zero. By configuring the second valve 42 as a flow rate variable valve in this way, the flow rate of the oxygen gas for fusing can be adjusted according to the type of object and environmental conditions, so the amount of CO ₂ generated can be easily reduced. .

Preferably, the first valve 41 and the second valve 42 are independently controllable. By making the first valve 41 and the second valve 42 independently controllable in this way, the intensity of the flame can be freely controlled according to the state of the blowout, thereby further suppressing an increase in the blowout time.

Specifically, for example, there is a case in which an interruption occurs due to a cut failure during fusion cutting, and the cutting is resumed from the position at which the cutting failure occurred. In such a case, since the object is not completely cooled, the first valve 41 is kept at the first opening for a certain period of time while supplying the fusing oxygen gas from the second valve 42. The object can be temporarily heated by the amount that has decreased to restore it. If priority is given to minimizing the fusing time, fusing may be performed by supplying oxygen gas for fusing from the second valve 42 while keeping the first valve 41 at the first opening.

<Third valve>
The third valve 43 controls the flow rate of the combustible gas supplied to the preheating gas pipe 33 . The third valve 43 is arranged in the combustible gas pipe 31 . More specifically, the third valve 43 is upstream of the position where the combustible gas pipe 31 joins the preheating gas pipe 33 and downstream of the combustible gas inlet 21 .

By controlling the flow rate of the combustible gas with the third valve 43, the preheating speed of the object is changed, and the fusing time and the amount of CO ₂ generated during preheating are determined. Therefore, it is preferable that the third valve 43 is configured by a flow rate variable valve.

<Fourth valve>
The fourth valve 44 controls the flow rate of the oxygen gas supplied to the preheating gas pipe 33 . The fourth valve 44 is arranged in the oxygen gas pipe 32 . More specifically, the fourth valve 44 is upstream of the position where the oxygen gas pipe 32 joins the preheating gas pipe 33 and downstream of the oxygen gas inlet 22 . The oxygen gas pipe 32 supplies oxygen gas from the oxygen gas inlet 22 to the preheating gas pipe 33 and the fusing gas pipe 34. As shown in FIG. 2, the upstream side thereof is a shared pipe. In this case, it is arranged on a flow path that supplies oxygen gas only to the fusing gas pipe 34 downstream from the branch position from this shared pipe.

By controlling the flow rate of the oxygen gas for preheating with the fourth valve 44, the flame state (combustion state) can be controlled. For this reason, it is preferable that the fourth valve 44 is configured by a flow rate variable valve.

In the blowpipe 1, since the mixed gas can be adjusted inside the blowpipe 1 using the third valve 43 and the fourth valve 44, the welding operator can easily adjust the flame at hand. In addition, since the blowpipe 1 can be used by preparing two gas cylinders or gas tanks for oxygen gas and combustible gas, the entire fusing equipment can be made simple.

<Advantages>
In the blowpipe 1, the first valve 41 can be controlled between a first opening at which the flow rate of the mixed gas of the combustible gas and the preheating oxygen gas is high and a second opening at which the flow rate is low. In some cases, the flow rate of the mixed gas can be reduced as the second degree of opening. During fusing, it is sufficient to maintain the state in which the object is oxidized by the oxygen gas for fusing, so high calorie is not required in the combustible gas, and even if the amount of hydrocarbon gas is reduced or eliminated, the increase in fusing time is suppressed. can. On the other hand, in the blowpipe 1, even if the amount of hydrocarbon gas is reduced or set to zero, the flow rate of the mixed gas can be increased by setting the opening to the first degree during preheating, and the calorie required for preheating can be secured. An increase in preheating time can also be suppressed. Therefore, by using the blowpipe 1, the hydrocarbon gas concentration can be reduced while maintaining the fusing time in the amount of CO ₂ generated determined by the hydrocarbon gas concentration x fusing time contained in the combustible gas. The blowpipe 1 can reduce the amount of CO ₂ generated.

[Gas fusion cutting method]
The gas fusion cutting method shown in FIG. 4 is a gas fusion cutting method for cutting an object by using a combustible gas containing hydrogen. The gas fusion cutting method can be performed using, for example, the blowpipe 1 shown in FIG. The gas fusion cutting method includes a flame forming step S1, a preheating step S2, a flow control step S3, and a fusion cutting step S4.

<Combustible gas>
The combustible gas includes hydrogen as described above. The combustible gas may consist only of hydrogen and unavoidable impurities, but preferably contains hydrocarbons. By including hydrocarbons in the combustible gas, the calorie obtained during combustion increases, and preheating or fusing can be performed in a short period of time.

Examples of the hydrocarbon include methane, ethane, ethylene, propane, propylene, liquefied petroleum gas (LPG), and liquefied natural gas (LNG). As the above hydrocarbon, those having 4 or less carbon atoms are preferable, and ethylene is more preferable. That is, the combustible gas preferably contains ethylene. By using the combustible gas containing ethylene as described above, the amount of CO ₂ generated can be reduced, and the quality of the finished state after gas fusing can be improved.

The combustible gas that can be suitably used in the blowpipe 1 of the present invention and the gas fusion cutting method of the present invention and that can particularly reduce the amount of CO ₂ generated contains more than 0% by volume and less than 18% by volume of ethylene, and the balance is hydrogen. and combustible gases that are inevitable impurities.

The ethylene concentration in the combustible gas is more than 0% by volume as described above, more preferably more than 1% by volume, and even more preferably more than 5% by volume. On the other hand, the ethylene concentration in the combustible gas is less than 18% by volume as described above, more preferably less than 15% by volume, and even more preferably less than 10% by volume. If the ethylene concentration is below the above lower limit, the effect of shortening the preheating time of the object may be insufficient. Conversely, if the ethylene concentration is equal to or higher than the above upper limit, the amount of CO ₂ generated may not be sufficiently reduced.

The upper limit of the concentration of the inevitable impurities is preferably 1.0% by volume, more preferably 0.5% by volume, and even more preferably 0.1% by volume. By making the concentration of the inevitable impurities equal to or lower than the upper limit, the characteristics of the combustible gas are likely to be stabilized. On the other hand, the lower limit of the concentration of the inevitable impurities is not particularly limited and may be 0% by volume. Here, the term "inevitable impurities" includes impurities that are unintentionally contained, as well as impurities that are intentionally added to the extent that the performance of the combustible gas is maintained. Such intentionally added impurities include nitrogen, oxygen, and moisture.

The combustible gas is stored under pressure in a container or tank. The pressure inside the container or tank is preferably lower than the pressure at which the gas enclosed in the container is not liquefied, and from the viewpoint of transportation efficiency, the higher the pressure. Specifically, the lower limit of the pressure inside the container or tank at 35° C. is preferably 1 MPa, more preferably 6 MPa. On the other hand, the upper limit of the pressure is preferably 50 MPa, more preferably 20 MPa. If the pressure is less than the lower limit, efficient transportation of the combustible gas may become difficult. Conversely, if the pressure exceeds the upper limit, ethylene may be liquefied and difficult to handle.

The pressures of the combustible gas and the oxygen gas supplied to the combustible gas inlet 21 and the oxygen gas inlet 22 of the blowpipe 1 are appropriately adjusted by a regulator or the like for the pressure in the container or tank. The lower limit of the pressure ratio of the combustible gas to the pressure of the oxygen gas after this adjustment is preferably 0.5, more preferably 0.75. On the other hand, the upper limit of the pressure ratio is preferably 2, more preferably 1.3. By setting the pressure ratio within the above range, when the first valve 41 of the blowpipe 1 is switched between the first opening and the second opening, the flow rate ratio between the combustible gas and the oxygen gas becomes extremely high. Since change can be suppressed, it is easy to stabilize the flame.

<Flame formation process>
In the flame forming step S1, the first valve 41 of the blowpipe 1 is set to the first degree of opening, and the second valve 42 shuts off oxygen gas for fusing while forming a flame.

At this time, the third valve 43 is used to adjust the flow rate of the combustible gas, and the fourth valve 44 is used to adjust the flow rate of the oxygen gas (oxygen gas for preheating) to adjust the flame to a suitable flame. can be done.

<Preheating process>
In the preheating step S2, the object is preheated by the flame formed in the flame forming step S1.

Specifically, the crater 10 of the blowpipe 1 is brought close to the target to be fused, and the target is heated by the flame. At this time, since the first valve 41 is set to the first degree of opening, the flow rate of the combustible gas is large, and the object can be heated quickly. When the object is sufficiently heated, fusing begins. The point at which the fusing starts is the point at which the preheating step S2 ends.

<Flow rate control process>
In the flow rate control step S3, after the preheating step S2, the first valve 41 is set to the second degree of opening. That is, in this step, the flow rate of combustible gas is reduced. In addition, the flow rate of the preheating oxygen gas is reduced together with the combustible gas.

<Fusing process>
In the fusing step S4, after the preheating step S2, the object is fused while supplying the oxygen gas for fusing.

Oxygen gas for fusing is supplied to the preheated object, which promotes oxidation and promotes fusing.

When the fusion cutting of the object is completed, the supply of oxygen gas for fusion cutting is stopped. If another object or another part of the same object is to be fused, the preheating step S2, the flow rate control step S3 and the fuse cutting step S4 are repeated. On the other hand, if there is nothing else to be fused, the fourth valve 44 and the third valve 43 are closed in this order to extinguish the flame, and the gas fuse method ends.

In the flow shown in FIG. 4, the fusing step S4 is started after the flow rate control step S3, but it is also possible to perform the flow rate control step S3 after the fusing step S4 is started. In this case, it is preferable to perform the flow rate control step S3 immediately after starting the fusing step S4.

<Advantages>
In the gas fusion cutting method, the blowpipe 1 of the present invention is used, the flow rate of the mixed gas is increased during preheating, and the flow rate of the mixed gas is decreased during fusion cutting. For this reason, in the amount of CO ₂ generated determined by the hydrocarbon gas concentration contained in the combustible gas x the fusing time, the hydrocarbon gas concentration can be reduced while maintaining the fusing time, so the gas fusing method can be used. can reduce the amount of _CO2 generated.

[Second embodiment]
Hereinafter, a blowpipe and a gas fusion cutting method according to a second embodiment of the present invention will be described with appropriate reference to the drawings.

[Blowpipe]
The blowpipe 2 shown in FIGS. 5 and 6 is a blowpipe for fusing an object using combustible gas containing hydrogen, and includes a central discharge port 10a and a plurality of blowpipes arranged so as to surround the central discharge port 10a. A crater 10 having a peripheral outlet 10b, a preheating gas pipe 33 for supplying a mixed gas of the combustible gas and preheating oxygen gas to the peripheral outlet 10b, and a fusing oxygen gas to the central outlet 10a. a first valve 45 for controlling the flow rate of the mixed gas flowing through the fusing gas pipe 34, the preheating gas pipe 33, and a second valve 42 for controlling the flow rate of the fusing oxygen gas flowing through the fusing gas pipe 34. The first valve 45 has a first opening that sets the flow rate of at least the mixed gas as a first flow rate, and a second opening that sets a second flow rate that is less than the flow rate of the first opening. , and the second valve 42 is configured to be able to shut off at least the oxygen gas for fusing.

The blowpipe 2 includes a combustible gas inlet 21 for taking in the combustible gas from the outside and an oxygen gas inlet 22 for taking in oxygen gas from the outside. a combustible gas pipe 31 connected to the pipe 33; oxygen connected to the oxygen gas inlet 22 and the preheating gas pipe 33 and also connected to the oxygen gas inlet 22 and the fusing gas pipe 34; A gas pipe 32 is further provided. Further, the blowpipe 2 includes a third valve 43 for controlling the flow rate of the combustible gas supplied to the preheating gas pipe 33, and a fourth valve 43 for controlling the flow rate of the oxygen gas supplied to the preheating gas pipe 33. and a valve 44 .

The blowpipe 2 can be configured in the same manner as the blowpipe 1 of the first embodiment except for the first valve 45, so the same reference numerals are given and detailed description thereof will be omitted.

<First valve>
The first valve 45, as shown in FIG. 5, comprises a pair of toggle valves 45a and a lever 45b for operating the toggle valves 45a.

As shown in FIG. 6, the pair of toggle valves 45a are arranged in the combustible gas pipe 31 and the oxygen gas pipe 32, respectively. The toggle valve 45a controls the flow rate of gas flowing through the toggle valve 45a by means of a toggle switch. Specifically, when the toggle switch is not pressed, the gas flow rate is kept low, and when the toggle switch is pressed, the gas flow rate is increased. The toggle valve 45a is configured so that the gas flow rate is kept low when the toggle switch is not touched. That is, the toggle valve 45a increases the gas flow rate only when the toggle switch is pressed.

The lever 45b controls toggle switches of a pair of toggle valves 45a. The lever 45b is provided outside the combustible gas pipe 31 and the oxygen gas pipe 32, and by tilting it toward the combustible gas pipe 31 and the oxygen gas pipe 32, the toggle switches of the pair of toggle valves 45a are turned on. It is configured so that it can be pressed simultaneously. Also, when the lever 45b is not touched, the lever 45b is kept at a position where the toggle switch is not pushed.

Since the first valve 45 is configured in this way, when the lever 45b is pushed, the first valve 45 is opened to the first degree of opening, increasing the gas flow rate. On the other hand, when the lever 45b is released, the first valve 45 is instantly set to the second opening, and the flow rate of the gas returns to the original flow rate, which is the second flow rate smaller than the flow rate of the first opening.

Although it is possible to provide one toggle valve 45a in the preheating gas pipe 33 for similar control, the flow rate of the mixed gas after mixing the combustible gas and oxygen is controlled. In this case, when the flow rate is switched from the first degree of opening to the second degree of opening, the mixed gas may flow backward due to an increase in resistance, and may enter the combustible gas pipe 31 and the oxygen gas pipe 32 . Then, the mixture ratio of the combustible gas and oxygen may deviate from the desired value due to the influence of the backflowing mixed gas. Therefore, it is preferable to arrange the toggle valve 45a in the combustible gas pipe 31 and the oxygen gas pipe 32, respectively, as in the present embodiment.

[Gas fusion cutting method]
The gas fusion cutting method using the blowpipe 2 is a gas fusion cutting method for cutting an object by using a combustible gas containing hydrogen. A flame forming step of forming a flame while shutting off the oxygen gas for fusing; a preheating step of preheating the object with the flame formed in the flame forming step; and a fusing step of fusing the object while supplying the fusing oxygen gas after the preheating step.

Each step is the same as the corresponding step of the gas fusion cutting method of the first embodiment, so detailed description is omitted.

[advantage]
In the blowpipe 2, since the first valve 45 is composed of a pair of toggle valves 45a and a lever 45b for operating the toggle valves 45a, it can be easily operated at hand. In addition, since the tip 10 is less likely to vibrate due to the operation of the first valve 45, it is possible to smoothly transition from preheating to fusing work. In addition, since the number of parts is small, the blowpipe 2 is unlikely to become heavy, so that it is possible to prevent a reduction in work efficiency of the fusing work using the blowpipe 2 .

[Other embodiments]
The above embodiments do not limit the configuration of the present invention. Therefore, in the above embodiment, the components of each part of the above embodiment can be omitted, replaced, or added based on the description of the present specification and common general technical knowledge, and all of them are interpreted as belonging to the scope of the present invention. should.

In the above embodiment, the blowpipe has a combustible gas inlet and an oxygen gas inlet, and the combustible gas and the oxygen gas are mixed inside the blowpipe. Alternatively, the mixed gas may be supplied to a blowpipe. In this case, the blowpipe is provided with a mixed gas inlet instead of the combustible gas inlet.

In this case, the combustible gas piping and the oxygen gas piping are omitted, and the mixed gas is directly supplied to the preheating gas piping, and the oxygen gas is directly supplied to the fusing gas piping. Also, the third valve and the fourth valve are omitted. That is, the flow rates of combustible gas and oxygen gas are controlled outside the blowpipe.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

As the combustible gas, four types of combustible gas containing ethylene and the balance being hydrogen and inevitable impurities were prepared with different ethylene concentrations (No. 1 to No. 4 in Table 1).

A steel plate having a thickness of 25 mm was prepared as an object to be fused.

Using each of the above-mentioned four types of combustible gases, the steel plate is preheated with the combustible gas fixed at 8 L / min, the oxygen gas for preheating is preheated at the flow rate shown in Table 1, and then 50 L / min. Fusing was performed by further adding oxygen gas for fusing.

The preheating time and the maximum cutting speed during this cutting were measured. The results are shown in the column of "Fixed at 8 L/min" in Table 1. The maximum fusing speed is a speed obtained by the following procedure. First, a blowpipe is attached to a traveling cart that can be set at any speed. A steel plate having a thickness of 25 mm is welded while the traveling truck is traveling at a constant speed. When the speed of the traveling carriage is low, melted pieces are cut off from the steel plate. From this low speed state, the speed of the traveling carriage is gradually increased to repeat fusing, eventually reaching a speed at which the fusing pieces cannot be cut off. At this time, the maximum value of the speed of the traveling carriage that is capable of fusing is defined as the maximum fusing speed.

The _CO2 index was calculated from the results in Table 1. Here, the " _CO2 index" is an amount calculated by ethylene concentration x flow rate of combustible gas x preheating time, and is an index representing the total amount of C supplied during preheating. Table 1 shows the results.

From the results in Table 1, the maximum fusing speed has relatively low dependence on the ethylene concentration of the combustible gas, while the preheating time significantly increases when the ethylene concentration drops below 40%. Therefore, even if the concentration of ethylene in the combustible gas is reduced to 10%, the amount of CO ₂ emitted increases rather than when the concentration of ethylene is 40%.

Next, according to the gas fusion cutting method of the present invention, each of the four types of combustible gases was used for fusion cutting. At this time, in the preheating process, the combustible gas and the oxygen gas for preheating are kept at the same flow rate ratio, and the preheating time is set to No. The first opening was set to the same flow rate of 7 seconds as in 4 (40% ethylene concentration). The set flow rate, preheating time, and _CO2 index of each combustible gas are shown in Table 1 in the column of "When the preheating process of the present invention is used." In addition, since the flow rate of the oxygen gas for fusing is the same as "when fixed at 8 L / min", the maximum fusing speed is also the same as "when fixed at 8 L / min", and the description is omitted in Table 1. there is

As can be seen from Table 1, by using the gas fusion cutting method of the present invention, the preheating time can be shortened and the amount of CO ₂ generated can be reduced. Among them, No. 1 containing more than 0% by volume and less than 18% by volume of ethylene, the balance being hydrogen and unavoidable impurities. When the combustible gas No. 1 is used, the amount of CO ₂ generated is 1/2 in the same preheating time as compared with the combustible gas with an ethylene concentration of 40%. From this, it can be seen that a combustible gas containing more than 0% by volume and less than 18% by volume of ethylene, with the balance being hydrogen and unavoidable impurities, is particularly effective in reducing the amount of CO ₂ generated.

As described above, the blowpipe of the present invention can reduce the amount of CO ₂ generated when an object is fused using combustible gas. In addition, the gas fusion cutting method of the present invention can reduce the amount of CO ₂ generated by using this blowpipe. Furthermore, the combustible gas of the present invention can reduce the amount of CO ₂ generated by using it in the blowpipe and the gas fusion cutting method.

1, 2 Blowpipe 10 Crater port 10a Central discharge port 10b Peripheral discharge port 11 Outer cylinder 12 Inner cylinder 13 Lid part 21 Combustible gas inlet 22 Oxygen gas inlet 31 Combustible gas pipe 32 Oxygen gas pipe 33 Preheating gas pipe 34 Fusing gas pipe 41 First valve 42 Second valve 43 Third valve 44 Fourth valve 45 First valve 45a Toggle valve 45b Lever

Claims (5)

A blowpipe for fusing an object using a combustible gas containing hydrogen,
a crater having a central outlet and a plurality of peripheral outlets arranged to surround the central outlet;
a preheating gas pipe for supplying the mixed gas of the combustible gas and the preheating oxygen gas to the peripheral outlet;
a fusing gas pipe that supplies oxygen gas for fusing to the central discharge port;
a first valve for controlling the flow rate of the mixed gas flowing through the preheating gas pipe;
a second valve for controlling the flow rate of the fusing oxygen gas flowing through the fusing gas pipe,
The first valve is controllable to at least a first degree of opening in which the flow rate of the mixed gas is a first flow rate and a second degree of opening in which a second flow rate is less than the flow rate of the first opening degree. can be,
The second valve is configured to be able to cut off at least the oxygen gas for fusing ,
A blowpipe in which the flow rate of the oxygen gas for preheating as well as the combustible gas is reduced by setting the first valve to the second opening degree. 2. The blowpipe of claim 1, wherein said first valve and said second valve are independently controllable. a combustible gas inlet for taking in the combustible gas from the outside;
an oxygen gas inlet for taking in oxygen gas from the outside;
a combustible gas pipe that supplies the combustible gas from the combustible gas inlet to the preheating gas pipe;
an oxygen gas pipe that supplies the oxygen gas from the oxygen gas inlet to the preheating gas pipe and the fusing gas pipe;
a third valve for controlling the flow rate of the combustible gas supplied to the preheating gas pipe;
3. The blowpipe according to claim 1, further comprising a fourth valve that controls the flow rate of the oxygen gas supplied to the preheating gas pipe. A gas fusing method for fusing an object using a combustible gas containing hydrogen,
Using the blowpipe according to claim 1,
a flame forming step of forming a flame while setting the first valve to the first opening degree and blocking the oxygen gas for fusing by the second valve;
a preheating step of preheating the object with the flame formed in the flame forming step;
a flow rate control step of setting the first valve to the second degree of opening after the preheating step;
A gas fusion cutting method comprising: a fusion cutting step of fusion cutting the object while supplying the oxygen gas for fusion cutting after the preheating step. 5. The gas cutting method according to claim 4, wherein the combustible gas contains ethylene.

Images