JP3916778B2 - Gas cutting crater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas cutting crater that cuts by blowing cutting oxygen to a portion while preheating a metal or the like with a preheating flame.
[0002]
[Prior art]
A conventional gas cutting crater will be described with reference to FIGS.
The gas cutting crater B in FIG. 5 has an internal crater 11 having a flow hole 11a for cutting oxygen at the center, an external crater 12 and a preheated oxygen and combustion gas between its inner surface 12n and the outer surface 11g of the internal crater 11. A mixed gas passage 13 is formed and fitted concentrically. The opening end 13a of the passage 13 is connected to the linear outer surface 11gs of the inner crater 11 parallel to the center line O and the linear outer surface 11gs. A tapered outer surface 11gt that narrows as it approaches, a linear inner surface 12ns of the external crater 12 parallel to the linear outer surface 11gs, and a tapered inner surface 12nt that narrows as it approaches the linear inner surface 12ns. Yes.
The linear outer surface 11gs of the inner crater 11 is a bottom surface of the groove 11c formed by the peaks 11b and 11b.
[0003]
Further, the gas cutting crater C in FIG. 7 has an internal crater 21 having a cutting oxygen circulation hole 21a in the center, an external crater 22 and a mixed gas between the inner surface 22n of itself and the outer surface 21g of the internal crater 21. A passage 23 is formed and concentrically fitted, and the open end 23a of the passage 23 is formed by converging the tapered outer surface 21gt of the inner crater 21 and the tapered inner surface 22nt of the outer crater 22 with each other. It is the structure formed by.
In this gas cutting crater, the tapered outer surface 21gt is the bottom surface of the groove 21c formed by the peaks 21b and 21b.
[0004]
[Problems to be solved by the invention]
6 and 8 show the shapes of the preheating flames FB and FC generated by the combustion of the mixed gas ejected from the passages 13 and 23 of the gas cutting craters B and C of FIGS. 5 and 7 and the white cores fb and fc. As shown, the white cores fb and fc of the gas cutting craters B and C are divergent.
For this reason, the following conditions:
Mixed gas: Preheated oxygen + combustion gas (propane gas)
Propane gas consumption: 300 Nl / h
Preheated oxygen consumption: 1050 Nl / h
Cutting oxygen pressure; 3 kg / cm ²
Material to be cut; Height of steel cut gas craters B and C such as SS, SM, etc. with a thickness of 12 mm;
As shown in FIGS. 4B and 4C, the piercing time of the gas cutting crater B is 45 seconds, and the piercing time of the gas cutting crater C is 35 seconds. However, the heating efficiency is low and piercing takes a long time.
[0005]
It is an object of the present invention to provide a gas cutting crater with good preheating flame heating efficiency and a short piercing time.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, there is provided an internal crater having a flow hole for cutting oxygen at a central portion, and an external crater is provided with a mixed gas between an inner surface of itself and an outer surface of the inner crater. In the gas cutting crater that is concentrically fitted to form a passage, the opening end of the passage is formed by a tapered outer surface tapered from the inner crater, and a crest using the tapered outer surface as a bottom surface. a groove, a straight inner surface parallel external crater and the center line is formed by said inner crater external crater tapered inner surface gap is reduced between the tapered outer surface with narrowed toward the straight line inner surface The peak portion of the inner crater is fitted to the linear inner surface of the outer crater .
[0007]
With this means, the white core of the preheating flame is unstenciled, and the degree of concentration is increased and the preheating flame is focused on one point, so that the heating efficiency is improved and the piercing time is shortened. In this configuration, the mixed gas mixed in the passage flows along the groove between the peaks and is ejected to the outside. Further, the mountain portion stabilizes the fitting of the external crater to the internal crater.
[0008]
In the gas cutting crater, the length of the linear inner surface of the external crater is preferably 1 mm or more (claim 2). When the length of the linear inner surface of the external crater is less than 1 mm, the concentration of the preheating flame is lowered. Even if the length of the straight inner surface of the external crater becomes larger than 5 mm, the concentration degree of the preheating flame does not increase greatly. Therefore, in general, the length of the linear inner surface of the external crater is about 5 mm at the maximum.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
In these figures, reference numeral A denotes a gas cutting crater according to the present invention, wherein an internal crater 1 having a cutting oxygen circulation hole 1a at the center, an external crater 2 and an inner surface 2n of itself and an outer surface 1g of the internal crater 1 are shown. A mixed gas passage 3 in which preheated oxygen and combustion gas are mixed is formed between them and concentrically fitted, and the opening end 3a of the passage 3 is tapered to the tapered outer surface 1gt of the inner crater 1 And a straight inner surface 2 ns of the external crater 2 parallel to the center line O and a tapered inner surface 2 nt that narrows toward the linear inner surface 2 ns.
[0011]
The tapered outer surface 1gt of the inner crater 1 is the bottom surface of the groove 1c formed by the peaks 1b and 1b, and the linear inner surface 2ns of the outer crater 2 is fitted to the straight portion of the peak 1b of the inner crater 1. ing. The internal crater 1 is screwed to the base 5, and the internal crater 1 is fitted into the base 5 and integrated with each other. The base 5 is provided with a cutting oxygen port 5a that communicates with the flow hole 1a, a preheated oxygen port 5b that communicates with the passage 3, and a combustion gas port 5c.
[0012]
In this gas cutting crater A, like the conventional gas cutting craters B and C, combustion gas such as preheated oxygen and propane gas is fed from the preheated oxygen port 5b and the combustion gas port 5c into the passage 3 and mixed. While the gas is ejected to the outside and the preheating flame FA is generated, the cutting oxygen is sent from the cutting oxygen port 5a to the flow hole 1a and ejected to cut the material to be cut.
[0013]
In the case of this gas cutting crater A, the white core fa is not constricted (constricted) as shown in FIG. Improved and focused on one point. For this reason, the heating efficiency of the material to be cut by the preheating flame FA was increased, and as shown in FIG. 4A, a good result was obtained in which the piercing time was shortened to 30 seconds.
[0014]
By the way, the reason why the concentration degree of the preheating flame FA (white core fa) is improved is estimated as follows.
That is, the outer surfaces 1gt, 11gs, and 21gt and the inner surfaces 2ns, 12ns, and 22nt of the inner crater 1 and the outer crater 2 that form the substantially annular passages 3, 13, and 23 form the mixed gas curtain that flows along them. To do.
[0015]
However, in the conventional gas cutting crater B of FIG. 5, the diffusion of the mixed gas (preheating flame) to the center side is suppressed by the gas curtain generated by the linear outer surface 11gt of the inner crater 11. The gas curtain due to the straight inner surface 12 ns is easily broken, and once the gas curtain is broken, the mixed gas is greatly diffused to the outside, so that the concentration of the white core fb is impaired.
[0016]
In addition, in the case of the conventional gas cutting crater C of FIG. 7, it seems that the mixed gas concentrates at one point, but since all the mixed gas flows at a steep angle to increase the internal pressure, The gas curtain formed by the tapered inner surface 22nt of the external crater 22 is easily broken, and as a result, the mixed gas diffuses outward and the concentration of the white core fc is reduced.
[0017]
In contrast, in the gas cutting crater A of the present invention, the outer surface 21gt of the inner crater 1 is tapered to guide the mixed gas to the center side, and the inner surface 2ns of the outer crater 2 is linear. In order to prevent the central pressure of the mixed gas from becoming excessive, the gas curtain formed by the linear inner surface 2 ns of the external crater 2 is less likely to fail and fulfills its function. Accordingly, the outward diffusion of the mixed gas is suppressed, and the white core fa becomes tapered to improve the concentration degree.
[0018]
Regardless of whether the inference is correct or not, the above effect occurs when the length L of the linear inner surface 2 ns of the external crater 2 is 1 mm or more, and hardly occurs when the length L is less than 1 mm. Therefore, in the gas cutting crater A of the present invention, the length L of the linear inner surface 2ns of the gas cutting crater 2 is 1 mm or more. However, since the effect does not increase even if the length L is greater than 5 mm, the length L of the linear inner surface 2 ns is usually in the range of 1 to 5 mm.
[0019]
In the present invention, the shape and number of the peaks 1b (grooves 1c) are arbitrary, and are not limited to those shown in the figure. The cutting conditions (piercing conditions) described above are only for experiments to demonstrate the effects of the present invention. For example, hydrogen, natural gas, or coal gas other than propane gas is used as the combustion gas. It goes without saying that almost the same effect can be expected even under other cutting conditions such as burning at a consumption corresponding to the above.
[0020]
【The invention's effect】
As described above, according to the present invention, the concentration degree of the preheating flame is increased. Therefore, the material to be cut can be efficiently heated with the preheating flame and pierced in a short time.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing an embodiment of a gas cutting crater according to the present invention.
FIG. 2 is a bottom view of the gas cutting crater of FIG. 1 with a cross section of the external crater.
FIG. 3 is a diagram showing a shape of a preheating flame and a white core of the gas cutting crater of FIG. 1;
FIG. 4 is a diagram showing experimental results of piercing.
FIG. 5 is a half sectional view of a conventional gas cutting crater.
6 is a diagram showing the shape of the preheating flame and white core of the gas cutting crater of FIG. 5. FIG.
FIG. 7 is a half sectional view of another conventional gas cutting crater.
8 is a diagram showing the shape of the preheating flame and white core of the gas cutting crater of FIG. 7. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Internal crater 1a Flow hole 1b Mountain part 1c Groove 1g Outer surface 1gt Tapered outer surface 2 External crater 2n Inner surface 2ns Linear inner surface 2nt Tapered inner surface 3 Passage 3a Open end A Gas cutting crater FA Preheating flame fa White core L Linear inner surface Length of

Claims (2)

In the gas cutting crater fitted concentrically with the outer crater forming a passage of mixed gas between the inner surface of the inner crater and the outer surface of the inner crater, in the inner crater having a flow hole for cutting oxygen in the center,
The opening end portion of the passage includes a tapered outer surface tapered from the inner crater, and a groove formed by a crest using the tapered outer surface as a bottom surface,
The center line parallel to the external crater linear inner surface, formed by the tapered inner surface of the outer crater gap is reduced between the inner crater tapered outer surface with narrowed toward the straight line inner surface,
A gas cutting crater, wherein a peak portion of the inner crater is fitted to a linear inner surface of the outer crater.   The gas cutting crater according to claim 1, wherein the length of the linear inner surface of the external crater is 1 mm or more.

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