JPH04162399A - Method for supplying plasma operating gas in plasma torch and plasma torch - Google Patents
Method for supplying plasma operating gas in plasma torch and plasma torchInfo
- Publication number
- JPH04162399A JPH04162399A JP2289939A JP28993990A JPH04162399A JP H04162399 A JPH04162399 A JP H04162399A JP 2289939 A JP2289939 A JP 2289939A JP 28993990 A JP28993990 A JP 28993990A JP H04162399 A JPH04162399 A JP H04162399A
- Authority
- JP
- Japan
- Prior art keywords
- working gas
- plasma
- operating gas
- gas supply
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 13
- 230000007423 decrease Effects 0.000 claims description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052721 tungsten Inorganic materials 0.000 abstract description 3
- 239000010937 tungsten Substances 0.000 abstract description 3
- 230000003247 decreasing effect Effects 0.000 abstract 4
- 239000007789 gas Substances 0.000 description 77
- 238000010586 diagram Methods 0.000 description 11
- 229910000831 Steel Inorganic materials 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000005192 partition Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000003139 buffering effect Effects 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
Landscapes
- Plasma Technology (AREA)
- Arc Welding In General (AREA)
- Coating By Spraying Or Casting (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、加熱装置、切断装置、溶射装置等に用いられ
るプラズマ発生装置に関し、さらに詳しくは雰囲気の巻
き込みの少ないプラズマト−チにおけるプラズマ作動ガ
ス供給方法およびプラズマトーチに関するものである。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a plasma generation device used in a heating device, a cutting device, a thermal spraying device, etc., and more specifically to a plasma generation device used in a plasma torch with less atmospheric entrainment. The present invention relates to a gas supply method and a plasma torch.
（従来の技術）
プラズマは清浄で制御性か良く超高温が比較的容易に得
られるエネルギ源として、近年、加熱装置、切断装置、
溶射装置等に広く使用されるようになっている。(Prior art) Plasma is a clean, easily controllable energy source that can reach ultra-high temperatures relatively easily, and has recently been used in heating devices, cutting devices,
It is now widely used in thermal spray equipment, etc.
製鋼プロセスにおいても新たな熱エネルギ源として各プ
ロセスに適用が図られており、例えば、製鋼工場におけ
る連続鋳造設備のタンデイツシュ内の溶鋼をプラズマに
よって加熱し、転炉から連続鋳造設備にいたるまでの温
度低下を補償するものとして、その導入が図られている
ところである。It is being applied to each process as a new thermal energy source in the steelmaking process. For example, plasma is used to heat molten steel in the tundish of continuous casting equipment at a steelmaking factory, and the temperature from the converter to the continuous casting equipment is increased. Efforts are being made to introduce it to compensate for the decline.
（「製鉄研究Ａ 第３３１号（１９８８） ）ところで
、プラズマ発生装置に用いられているプラズマトーチの
概略は第５図に示されるように、中心部に電極５１を配
設し、この電極５１の外周に内部に水冷の循環経路を有
するノズル５２を設け、電極５１とノズル５２の間にプ
ラズマ作動ガス流路５３を形成せしめてなり、このプラ
ズマ作動ガス流路５３からプラズマ作動ガス（以下、単
に作動ガスという）か供給される。("Steel Research A No. 331 (1988))" By the way, as shown in FIG. 5, a plasma torch used in a plasma generator has an electrode 51 disposed in the center. A nozzle 52 having a water-cooled circulation path inside is provided on the outer periphery, and a plasma working gas flow path 53 is formed between the electrode 51 and the nozzle 52. From this plasma working gas flow path 53, plasma working gas (hereinafter simply referred to as (referred to as working gas) is supplied.
（発明か解決しようとする課題）
前述のプラズマトーチを用いてプラズマによって加熱す
るためには、安定的な高出力か必要であり、プラズマト
ーチにおける出力Ｗは次式で表すことかでき、すなわち
、
ｗ＝ｖｒもしくＷ＝ｒ２Ｒ
である。ここて、Ｗ：出力、Ｖ：電圧、１：電流、Ｒ：
抵抗である。(Problems to be Solved by the Invention) In order to heat with plasma using the plasma torch described above, a stable high output is required, and the output W of the plasma torch can be expressed by the following formula, that is, w=vr or W=r2R. Here, W: output, V: voltage, 1: current, R:
It is resistance.
したかって、高出力を得るためには、上式から電流と電
圧を大きくすればよいことかわかるが、電流値を大きく
するとジュール熱により電極の消耗量を増大させ電極の
寿命低下を招くことになる。このため、一般には作動ガ
ス中の電気抵抗を大きくして、電流値を小さく抑え、電
圧を大きくとることによって高出力を得ている。Therefore, in order to obtain high output, it can be seen from the above equation that it is necessary to increase the current and voltage, but increasing the current value will increase the amount of electrode wear due to Joule heat and shorten the life of the electrode. Become. For this reason, high output is generally obtained by increasing the electrical resistance in the working gas, keeping the current value low, and increasing the voltage.
ところか、プラズマトーチから噴出される作動ガスは超
高温・超高速であることから雰囲気との流速差か大きい
ため、作動ガスの流れに雰囲気を巻き込むことになり、
このため、劣悪な雰囲気、例えば溶鋼加熱に使用する場
合、雰囲気に存在する金属蒸気、フラックスガス、ダス
ト、酸素などを作動ガスの流れに巻き込むことになる。However, since the working gas ejected from the plasma torch is extremely high temperature and extremely high speed, there is a large flow velocity difference between it and the atmosphere, which causes the atmosphere to be involved in the flow of the working gas.
For this reason, when used in a poor atmosphere, for example for heating molten steel, metal vapor, flux gas, dust, oxygen, etc. present in the atmosphere are involved in the flow of working gas.
したがって、溶鋼への吸収がなく、がっ溶鋼を酸化させ
ないＡｒを、作動ガスに使用していても、金属蒸気、フ
ラックスガス、ダストなとを巻き込むために作動ガス中
のインピーダンス（電気抵抗）を低下させることになり
、電流値を小さく抑えて電圧を大きくして高出力を得る
ことができなくなるという問題がある。Therefore, even if Ar, which is not absorbed into molten steel and does not oxidize molten steel, is used as the working gas, the impedance (electrical resistance) in the working gas is increased because it involves metal vapor, flux gas, dust, etc. Therefore, there is a problem in that it is not possible to suppress the current value to a small value and increase the voltage to obtain high output.
特に、溶鋼面から発生した金属蒸気は、２次アークの発
生を助長するとともに、プラズマアークを移行しやすく
するため、アーク長を大きくしても、トーチ間で金属蒸
気を介して非移行アークか発生するため、電圧を大きく
しにり＜シている。In particular, the metal vapor generated from the molten steel surface promotes the generation of secondary arcs and makes it easier for the plasma arc to transfer. Therefore, even if the arc length is increased, a non-transferred arc may be generated between the torches via the metal vapor. This occurs, so the voltage must be increased.
また、雰囲気中の酸素は電極にタングステンを使用して
いる場合、５００°Ｃ以上でタングステンを急激に酸化
し、酸化タングステンを形成し、この酸化タングステン
は６００°Ｃ程度で激しく昇華し、電極の消耗を速める
ことになる。In addition, when tungsten is used for the electrode, oxygen in the atmosphere rapidly oxidizes the tungsten at temperatures above 500°C, forming tungsten oxide, and this tungsten oxide sublimates violently at about 600°C, forming the electrode. This will accelerate wear and tear.
（課題を解決するための手段）
本発明は上記の問題点を解決するためのプラズマ作動ガ
スと雰囲気との流体剪断抵抗を小さくする方法とその装
置に係わるもので、第１発明は、中心部に電極を配置し
、その外周に複数のプラズマ作動ガス供給流路を配設し
、前記複数の供給流路に作動ガスを供給するに際し、前
記供給流路に対するプラズマ作動ガスの流速を外周に到
るにしたがい低流速となるように供給するプラズマトー
チにおけるプラズマ作動ガス供給方法である。(Means for Solving the Problems) The present invention relates to a method and an apparatus for reducing fluid shear resistance between a plasma working gas and an atmosphere in order to solve the above-mentioned problems. A plurality of plasma working gas supply passages are arranged around the outer periphery of the electrode, and when supplying working gas to the plurality of supply passages, the flow velocity of the plasma working gas with respect to the supply passage is controlled to reach the outer periphery. This is a method of supplying plasma working gas in a plasma torch such that the flow rate decreases as the temperature increases.
第２発明は、中心部に電極を配置し、その外周に複数の
プラズマ作動ガス供給流路を配設したプラズマトーチで
ある。The second invention is a plasma torch in which an electrode is arranged in the center and a plurality of plasma working gas supply channels are arranged around the outer periphery of the electrode.
（作用）
本発明者等は作動ガスによる雰囲気の巻き込み状況がノ
ズルと電極の位置関係でとのように変化するか数値解析
を行い、雰囲気の巻き込みやすさの判定基準として、乱
流エネルギを用いて検討した。すなわち、乱流エネルギ
の大きい流れほど、小さな渦を流れの中に多く保有して
おり、雰囲気を巻き込みやすいと言える。数値解析結果
を第４図に示す。第４図は作動ガスの供給における乱流
エネルギ（速度変動成分の平均値）分布を示し、（ａ）
は従来法（作動ガス供給流路−個’） 、（ｂ）は作動
ガス供給流路二個のものである。なお、図は中心線を挟
んで上下対象のため、下部は省略しである。また、（ｂ
）（供給流路二個のもの）については、外側の作動ガス
供給流路からの作動ガスの供給速度は内側からの供給速
度の１／２である。(Function) The inventors conducted a numerical analysis to determine whether the entrainment of the atmosphere by the working gas changes depending on the positional relationship between the nozzle and the electrode, and used turbulence energy as a criterion for determining the ease of entrainment of the atmosphere. I considered it. In other words, it can be said that the higher the turbulence energy, the more small vortices the flow has, and the more likely it is to entrain the atmosphere. Figure 4 shows the numerical analysis results. Figure 4 shows the turbulence energy (average value of speed fluctuation components) distribution in the supply of working gas, (a)
is the conventional method (one working gas supply channel), and (b) is the one with two working gas supply channels. Note that the lower part is omitted because the figure is vertically symmetrical across the center line. Also, (b
) (with two supply passages), the supply rate of working gas from the outer working gas supply passage is 1/2 of the supply rate from the inside.
第４図から明らかなように、（ｂ）の乱流エネルギ分布
のピークは（ａ）のそれよりも低くなっている。このこ
とは、外側の作動ガス供給流路からの作動ガスの供給速
度を小さくして雰囲気との相対速度を小さくすることが
、乱流エネルギを小さく抑え、雰囲気の巻き込みを抑制
する緩衝作用を持つことを示している。As is clear from FIG. 4, the peak of the turbulent energy distribution in (b) is lower than that in (a). This means that reducing the supply speed of the working gas from the outer working gas supply channel to reduce the relative velocity with the atmosphere has a buffering effect that suppresses turbulence energy and suppresses the entrainment of the atmosphere. It is shown that.
したかって、プラズマトーチに複数の作動ガス供給流路
を設けて、作動ガスを複数層にして供給する方法は、外
側の作動ガス供給流路から供給する作動ガスが雰囲気と
の緩衝作用を持つことになり、作動ガスの供給による雰
囲気の巻き込みを軽減することができ、かつ、内側の作
動ガス供給流路から供給される作動ガスはより安定した
流れとなる。なお、作動ガス供給流路からの作動ガスの
供給速度は、雰囲気の巻き込みを抑制する緩衝作用を持
たせるために、内側から外側に到るにしたがい、低速度
にする必要がある。Therefore, the method of providing a plurality of working gas supply channels in a plasma torch and supplying working gas in multiple layers requires that the working gas supplied from the outer working gas supply channels have a buffering effect with the atmosphere. Therefore, the entrainment of the atmosphere due to the supply of the working gas can be reduced, and the working gas supplied from the inner working gas supply channel has a more stable flow. Note that the supply speed of the working gas from the working gas supply channel needs to be lowered from the inside to the outside in order to provide a buffering effect that suppresses the entrainment of the atmosphere.
（実施例） 以下に本発明の実施例について説明する。(Example) Examples of the present invention will be described below.
第１図は本発明に係わるプラズマト−チの概略図を示す
。図中Ｉは電極、２はノズル、３は隔壁、４は第１の作
動ガス供給流路、５は第２の作動ガス供給流路、６は作
動ガス供給流路、７は速度調節器を示す。ノズル２と電
極Ｉの間に隔壁３を設け、この隔壁３て第１の作動ガス
供給流路４と第２の作動ガス供給流路５を分離する。第
１の作動ガス供給流路４と第２の作動ガス供給流路５は
速度調節器７を介して作動ガス供給路６に接続されてい
る。なお、ノズル２の冷却は第５図に示す方法と同様に
循環冷却水で行っている。FIG. 1 shows a schematic diagram of a plasma torch according to the present invention. In the figure, I is an electrode, 2 is a nozzle, 3 is a partition, 4 is a first working gas supply channel, 5 is a second working gas supply channel, 6 is a working gas supply channel, and 7 is a speed regulator. show. A partition wall 3 is provided between the nozzle 2 and the electrode I, and the partition wall 3 separates the first working gas supply channel 4 and the second working gas supply channel 5. The first working gas supply passage 4 and the second working gas supply passage 5 are connected to a working gas supply passage 6 via a speed regulator 7 . Note that the nozzle 2 is cooled using circulating cooling water in the same manner as shown in FIG.
作動ガスの供給にあたっては、作動ガス供給流路６から
の作動ガスを速度調節器７で第１の作動ガス供給流路４
と第２の作動ガス供給流路５の二つに分け、かつ、それ
ぞれの供給速度に調節して、第１の作動ガス供給流路４
と第２の作動ガス供給流路５から供給する。When supplying the working gas, the working gas from the working gas supply passage 6 is transferred to the first working gas supply passage 4 using the speed regulator 7.
and the second working gas supply channel 5, and adjust the supply speed of each to the first working gas supply channel 4.
and is supplied from the second working gas supply channel 5.
つぎに、このプラズマト−チにおける供給作動ガスによ
る雰囲気の巻き込み状態について説明する。雰囲気の巻
き込み状態は作動ガスの雰囲気への拡散状態を数値解析
することによって求めた。Next, the state of the atmosphere being drawn in by the supplied working gas in this plasma torch will be explained. The entrainment state of the atmosphere was determined by numerically analyzing the state of diffusion of the working gas into the atmosphere.
作動ガスにはＡｒを用い、雰囲気のＡｒ濃度は０％とし
た。解析結果を第２図に示す。第２図は作動ガスの濃度
分布を示し、（ａ）は従来法（作動ガス供給流路−個）
、（ｂ）は本発明法によるものである。なお、図は中
心線を挟んで上下対象のため、下部は省略しである。ま
た、本発明法については、第２の作動ガス供給速度は第
１の作動ガス供給速度の１／２である。Ar was used as the working gas, and the Ar concentration in the atmosphere was 0%. The analysis results are shown in Figure 2. Figure 2 shows the concentration distribution of the working gas, and (a) is the conventional method (working gas supply channel - pieces).
, (b) are obtained by the method of the present invention. Note that the lower part is omitted because the figure is vertically symmetrical across the center line. Further, in the method of the present invention, the second working gas supply rate is 1/2 of the first working gas supply rate.
第２図から明らかなように、本発明法（ｂ）のＡｒの雰
囲気への拡散濃度は従来法（ａ）のそれよりも高（なっ
ている。一方、ノズル中心部のＡｒ濃度は従来法（ａ）
のそれよりも高く安定している。すなわち、本発明法の
方が従来法よりも雰囲気の巻き込みが少ないことを示し
ている。As is clear from Fig. 2, the concentration of Ar diffused into the atmosphere in method (b) of the present invention is higher than that in conventional method (a).On the other hand, the Ar concentration in the center of the nozzle is lower than that in the conventional method. (a)
It is higher and more stable than that of . In other words, it is shown that the method of the present invention causes less atmospheric entrainment than the conventional method.
作動ガスにＡｒを用いた溶鋼加熱の実操業では、雰囲気
の巻き込みが少ないため、電流値を小さく抑えた高出力
操業か可能で、ジュール熱による電極の消耗も最小限に
することがてきた。In the actual operation of heating molten steel using Ar as the working gas, there is little entrainment of the atmosphere, so high output operation with a low current value is possible, and wear on the electrodes due to Joule heat has been minimized.
第３図に変形実施例のプラズマトーチの概略図を示す。FIG. 3 shows a schematic diagram of a plasma torch of a modified embodiment.
第３図は隔壁３をノズル２の先端より引っ込めたもので
、こうすることによって、第２の作動ガス供給流路５か
ら供給される作動ガスの流れがノズル２の先端により内
側に向けられ、作動ガスの持つ圧力の解放方向は内向き
となり、雰囲気の巻き込みをさらに軽減することかでき
る。In FIG. 3, the partition wall 3 is retracted from the tip of the nozzle 2. By doing so, the flow of the working gas supplied from the second working gas supply channel 5 is directed inward by the tip of the nozzle 2. The release direction of the pressure of the working gas is inward, making it possible to further reduce the entrainment of the atmosphere.
（発明の効果）
以上説明したように本発明は、作動ガスの供給による雰
囲気の巻き込みを軽減するために、複数の作動ガスの供
給流路を設けたプラズマトーチを用いて、作動ガスを多
層にして供給し、外側の作動ガスの供給速度を内側の作
動ガスの供給速度よりも小さ（して供給する方法である
。このプラズマトーチを用いて作動ガスを供給すること
によって、金属蒸気、フラックスガス、ダスト、酸素な
どの作動ガスおよび電極に悪影響を及ぼす雰囲気におい
ても、電流値を小さく抑えて高出力を得ることができ、
かつ電極の消耗も最小限にすることかできる。(Effects of the Invention) As explained above, the present invention uses a plasma torch provided with a plurality of working gas supply channels to spread the working gas in multiple layers in order to reduce the entrainment of the atmosphere due to the supply of the working gas. In this method, the working gas on the outside is supplied at a lower speed than the working gas on the inside.By supplying the working gas using this plasma torch, metal vapor, flux gas, etc. Even in atmospheres that adversely affect working gases and electrodes such as dust, oxygen, etc., the current value can be kept low and high output can be obtained.
Moreover, the consumption of electrodes can also be minimized.
第１図は本発明に係わるプラズマトーチの概略図を示す
。
第２図（ａ）は従来法の、（ｂ）は本発明方の作動ガス
の濃度分布を示す図である。
第３図は変形実施例のプラズマ）・−チの概略図を示す
図である。
第４図（ａ）は従来法の、（ｂ）は作動ガス供給流路二
個のものの乱流エネルギ分布を示す図である第５図は従
来技術のプラズマト−チの概略図を示す図である。
ｌ・電極、２ ノズル、３−隔壁、４−第１の作動ガス
供給流路、５−第２の作動ガス供給流路、６・−作動ガ
ス供給流路、７−速度調節器、５１電極、５２−ノズル
、５３．プラズマ作動ガス流路。
特許出願人 株式会社 神戸製鋼所
代 理 人 弁理士 金丸 章−FIG. 1 shows a schematic diagram of a plasma torch according to the invention. FIG. 2(a) is a diagram showing the concentration distribution of the working gas in the conventional method, and FIG. 2(b) is a diagram showing the concentration distribution of the working gas in the method of the present invention. FIG. 3 is a diagram showing a schematic diagram of a plasma of a modified embodiment. FIG. 4(a) is a diagram showing the turbulent energy distribution of the conventional method, and FIG. 4(b) is a diagram showing the turbulent energy distribution of the two working gas supply channels.FIG. 5 is a diagram showing a schematic diagram of the conventional plasma torch. It is. l-electrode, 2-nozzle, 3-partition wall, 4-first working gas supply channel, 5-second working gas supply channel, 6-working gas supply channel, 7-speed regulator, 51 electrode , 52-nozzle, 53. Plasma working gas flow path. Patent applicant: Kobe Steel, Ltd. Representative Patent attorney: Akira Kanemaru
Claims (2)
マ作動ガス供給流路を配設し、前記複数の供給流路に作
動ガスを供給するに際し、前記供給流路に対するプラズ
マ作動ガスの流速を外周に到るにしたがい低流速となる
ように供給することを特徴とするプラズマトーチにおけ
るプラズマ作動ガス供給方法。(1) An electrode is arranged in the center, a plurality of plasma working gas supply channels are arranged around the outer periphery, and when supplying working gas to the plurality of supply channels, the plasma working gas is supplied to the supply channels. A method for supplying plasma working gas in a plasma torch, characterized in that the flow velocity is supplied so that the flow velocity decreases toward the outer periphery.
マ作動ガス供給流路を配設したことを特徴とするプラズ
マトーチ。(2) A plasma torch characterized in that an electrode is arranged in the center and a plurality of plasma working gas supply channels are arranged around the outer periphery of the electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2289939A JP2857247B2 (en) | 1990-10-25 | 1990-10-25 | Plasma working gas supply method in plasma torch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2289939A JP2857247B2 (en) | 1990-10-25 | 1990-10-25 | Plasma working gas supply method in plasma torch |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04162399A true JPH04162399A (en) | 1992-06-05 |
| JP2857247B2 JP2857247B2 (en) | 1999-02-17 |
Family
ID=17749701
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2289939A Expired - Fee Related JP2857247B2 (en) | 1990-10-25 | 1990-10-25 | Plasma working gas supply method in plasma torch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2857247B2 (en) |
-
1990
- 1990-10-25 JP JP2289939A patent/JP2857247B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2857247B2 (en) | 1999-02-17 |
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