EP0378461A1 - Cutting nozzle for iron and steel processing - Google Patents

Abstract

The invention concerns a cutting torch for iron and steel metallurgy which is provided with two oxygen cutting ducts, ending in two housings, for receiving two cutting inserts, or a heating nozzle and a cutting insert. In this manner, there is obtained a torch which may very rapidly be converted into a cutting torch with high heating capacity and single cutting jet, or into a cutting torch with high cutting speed provided with two cutting inserts.

Description

The cutting nozzles commonly used in the iron and steel industry for hot flame cutting of large thicknesses, or cold slitting, are generally in one piece, made of copper, with a central oxygen jet and most of them they have two concentric heating rings with an oxygen jet.

French patent ^No. 86.11.008 proposes a new design of injectors for oxygen supply to the Antifriction central heating and a realization of this two-part cutting nozzle, thereby optimizing the output gas velocities heating, while offering the user the advantage of only changing the cutting block in the event of an incident leading to deterioration of the visible part of the nozzle.

As indicated above, the most commonly used technology in the design of cutting nozzles for very thick layers is the double heating ring concentric with a central oxygen jet with an external ring, with a highly oxidizing flame, allowing to heat the top of the slab to be flame-cut, has a heating ring located between this outer ring and the central cutting jet, with a very combustible flame, to obtain a long plume around the cutting jet which, driven by the latter. partly fits into the cutting groove and helps to heat the middle and bottom part of the groove.

For the oxygen jet, the so-called Laval nozzle is the most commonly used to obtain a high exit speed without bursting of the jet.

However, the use of a single cutting jet at very high speed, therefore at very high pressure, has its limits because it can contribute to causing insufficient heating in the middle part of the bleeding, which results, especially in flame cutting. when cold, scouring detrimental to the quality of cut.

This is the reason why French patent 87.04.523 has proposed a flame-cutting nozzle comprising two jets of cutting oxygen, with between them a central duct for a fuel heating flame, ensuring a resumption of heating. deep into the raw cutting groove, which was made by the first oxygen jet and which is finished by the second oxygen jet. Such a nozzle can be produced in two parts or in one piece in one piece.

It should be noted that the improvement in heating at the bottom of the bleeding associated with two jets of cutting oxygen at high pressure has enabled the cutting speed to be increased by 20% when cold and 10% when hot, compared to the most efficient conventional single-jet processes.

The applicant has set itself the goal of simultaneously solving three problems, namely:
- As the production of the cutting duct, and in particular the machining of the Laval nozzle, is a decisive element for obtaining good performance (width of the groove and cutting speed), this production is delicate and expensive, taking into account the size of the nozzles currently sold, and the invention aims to simplify this operation.
- On the other hand, the user of the material is currently obliged to have two types of nozzles depending on whether he wants to favor the cutting speed (nozzle with two cutting jets) or the bleeding width (nozzle with single cutting jet ), and the invention aims to combine these two functions in one and the same nozzle.
- Finally, from experience, the life of a cutting nozzle is directly linked, under normal conditions of use, to the life of the cutting duct. With current designs, we are obliged, in the event of a drop in performance when they are observed, after cleaning the nozzle, to change either the cutting block in the single-jet version, or the complete nozzle in the two-jet version , and the invention aims to further limit the parts to be changed. The objective is therefore another nozzle design, making it possible to solve the three problems set out above, while preserving, or even improving, the performance of the two processes and ensuring industrial reliability for the equipment.

The cutting nozzle according to the present invention, of the type with cutting oxygen jet and heating ring around said jet, is characterized in that it comprises a nozzle body with two conduits connected to an oxygen supply conduit cutting ending in two housings aligned along a diametrical axis, with a fuel mixture supply means opening at one of said housings, said first housing, said nozzle body being associated with at least one set of three inserts , including two so-called cutting inserts adapted to engage one in the first housing with closure of the outlet of the fuel mixture supply means and communication with the cutting oxygen conduit, the other in the second housing, the third insert being an additional heating nozzle adapted to engage, in place of the first cutting insert, in the first housing with establishment of communication of nozzle heating conduits with the supply means combustible mixture.

Thus, the nozzle can be used in two versions, namely a single jet version associated with a heating nozzle conferring a remarkable surface heating power just before the intervention of the cutting jet while by carrying out a simple removal of the said heating nozzle and by engaging a cutting insert - which is located in front of the cutting jet of the initial cutting insert -, there is produced, practically with the same essential constituents of the nozzle body, a nozzle with two particularly fast acting cutting jets.

According to a preferred embodiment, the nozzle body comprises two bodies engaged one on the other, namely a body made of injectors with core and injector head with a stepped plurality of grooves for supplying gaseous constituents , (heating oxygen, cutting oxygen, combustible gas), forming an abutment shoulder for an annular body known as heating, with fixing means with determined angular orientation of said annular heating body on said injector body core, said annular heating body incorporating longitudinal heating conduits in alignment with homologous conduits of the injector head, which are connected on the one hand to a conduit opening into a fuel supply groove, on the other hand to a said injector conduit opening into a heating oxygen supply groove, the fuel mixture supply means at the first insert housing forming a chamber transverse supplied with combustible mixture by longitudinal conduits each connected on the one hand to a conduit leading to the fuel supply groove on the other hand to a said injector conduit connected to a groove for supplying heating oxygen. Here we find the realization in two parts, known per se, however adapted to the new function of receiving cutting inserts and / or removable and swappable heaters. Thanks to the transverse chamber for supplying a fuel mixture with a low oxygen content, therefore a high fuel content, it is possible, on the one hand, to complete the supply of the heating nozzle which is carried out in part by a head with an oxygen intake duct known as a cut-out opening into longitudinal nozzle heating ducts, on the other hand supplying a longitudinal fuel mixture with fuel mixture interlayer formed between the two insert housings.

• - la figure 1 est une vue en coupe du corps de buse avec une busette de chauffe et un injecteur de coupe en position non montée ;
• - la figure 2 est une demi-vue partielle analogue à la figure 1, avec décalage angulaire ;
• - la figure 3 est une vue analogue à la figure 1, avec la busette de chauffe et l'injecteur de coupe en position montée ;
• - la figure 4 est une vue frontale selon les flèches III-III de la buse selon la figure 3 ;
• - la figure 5 est une vue en coupe du corps de buse selon la figure 1, équipé de deux injecteurs de coupe ;
• - la figure 6 est une vue frontale selon la direction VI-VI de la figure 5 ;
• - la figure 7 est une vue en coupe transversale selon la ligne VII-VII de la figure 5.
• - les figures 8 et 9 sont des vues de détails à échelle agrandie des figures 5 et 3 respectivement.

The characteristics and advantages of the invention will become apparent from the following description, by way of example, with reference to the accompanying drawings in which:

• - Figure 1 is a sectional view of the nozzle body with a heating nozzle and a cutting injector in the unassembled position;
• - Figure 2 is a partial half-view similar to Figure 1, with angular offset;
• - Figure 3 is a view similar to Figure 1, with the heating nozzle and the cutting injector in the mounted position;
• - Figure 4 is a front view along arrows III-III of the nozzle according to Figure 3;
• - Figure 5 is a sectional view of the nozzle body according to Figure 1, equipped with two cutting injectors;
• - Figure 6 is a front view in the direction VI-VI of Figure 5;
• - Figure 7 is a cross-sectional view along line VII-VII of Figure 5.
• - Figures 8 and 9 are detail views on an enlarged scale of Figures 5 and 3 respectively.

Referring to the accompanying drawings, a cutting nozzle 1 is mounted on a torch body 2 (shown in broken lines) and incorporating an axial cutting oxygen supply duct 3, a heating oxygen supply duct 4 subdivided into two conduits 4 ′ and 4˝, and a fuel supply conduit 5.

The cutting nozzle comprises a central body called a body called injectors 11, on which a so-called heating body 12 is fixed.

The injector body 11 comprises an upstream part 13 of generally frustoconical shape adapted to engage in the torch body 2 and having three axially stepped grooves 14, 15, 16, one of which 14, comes opposite the outlet of fuel supply duct 5, thus forming an annular fuel distribution chamber 14, and the other two 15 and 16 of which come opposite the outlets respectively for the ducts 4 ′ and 4˝ for supplying heating oxygen, thus forming two annular distribution chambers for heating oxygen 15 and 16 arranged axially on either side of the fuel chamber 14. A large axial duct 18 presents itself opposite the outlet of the cutting oxygen conduit 3, while there are, from the periphery inward;
- At the periphery an annular plurality (eight in the drawing) of longitudinal conduits 21, called cleanliness, starting from the transverse chamber for supplying heating oxygen 16 and all emerging through a shoulder 22 of injector block 11 ;
- two longitudinal conduits known as preheating 23 and 24 supplied with fuel via a conduit 25 starting from the fuel chamber 14 and via a small injector conduit 26 starting from the annular heating oxygen chamber 16 and all opening out through a shoulder 22 of the injector block 11 (cf. FIGS. 1, 3, 5 and 8);
- An annular plurality (sixteen in the drawing) of so-called heating conduits 28 inclined outward and downstream, supplied with oxygen by an injector conduit 29 starting from the annular heating oxygen chamber 15 and by a conduit 30 starting from the annular fuel chamber 14 and all opening out through the shoulder 22 of the injector body 11;
- interposed between certain conduits of the ring of heating conduits 28 are arranged (cf. FIG. 2) an annular plurality of fuel heating conduits 31 connected via a conduit 32 to the fuel supply chamber 14 and via a conduit 33 to injector 34 starting from the heating oxygen supply chamber 16. These fuel heating conduits 31 are longitudinal and, unlike the heating conduits 28, which, inclined towards the outside, open out through the upstream shoulder 22, extend in a downstream part in the form of a core 35 of the injector body 11 until opening out through a terminal end face 36 of this injector body 11;
the cutting oxygen pipe 18 is subdivided into two pipes 37 and 38, the axes of which are in a mean diametrical plane between the preheating pipes 23 and 24 and opening out through the front face 36.

The heating body 12 is in the form of an annular part with, on the upstream side, an internal face 41 slidably mounted on the external face 42 of the core 35 of the injector body 11 until it abuts against the shoulder 22 of this injector body 11, with a predetermined orientation by means of pins 43 relative to the injector body 11, and by virtue of a key 44 relative to the torch body 2. On the downstream side, the heater body 12 closes in a solid piece 61 beyond a cut annular face 62 whose most flared diameter is located at a short distance from the front face 36 of the injector block 11, so as to form a circular transverse groove 55 in which open the fuel heating pipes 31.

This heating corpos 12 has a radially outward collar 45 in which are formed longitudinal conduits 46 in exact extension of the cleanliness conduits 21 of the injector body 11 and opening at 47. Likewise, two longitudinal preheating conduits 48 and 49 are in exact extension of the two preheating pipes 23 and 24 of the injector body 11 to open at 50 and 51 through the front transverse face 52 of the heating body 12. Also heating pipes 53 inclined towards the downstream and towards the center, arise upstream in exact look - not visible in the drawings - of the outlet of the heating conduits 28 of the injector body 11, to emerge at 54 through the transverse face 52 of the heater body 12 The heating body 12 also has two large longitudinal perforations 56 and 57 which are presented axially in the extension of the cutting oxygen conduits 37 and 38.

These perforations 56 and 57 as well as a flared end portion 58 and 59 of the conduits 37 and 38 serve as housings for a cutting insert 63, a second cutting insert 64 or an insert forming a heating nozzle 65.

The cutting insert 63, or 64, has a wide duct 66 with convergent-divergent nozzle 67. It has on its external face a thread 68 adapted to cooperate with a thread 59 of the housing at 58 and 59 and an annular plurality of millings longitudinal 69. In the mounted position (Figures 3 and 5), a cutting insert 63 (Figure 3) or 63-64 (Figure 5) is fully screwed into a housing (57-59) and / or (56- 58), the axial duct 66 being supplied with cutting oxygen by the duct 38 (FIG. 3) by the ducts 38 and 37 (FIG. 5), while the countersinks 69 form, with the wall of the housings 56 or 57, an annular ring of conduits 69 around the axial conduit 66, connected upstream to the fuel mixing chamber formed by the circular groove 55 itself supplied by the conduits 31.

A heating nozzle 65 has a head 70 with a gasket 71 with an axial duct 72 opening radially through conduits 73 in a groove 74 forming, in the mounted position, an oxygen dispensing chamber 74 (called cutting chamber which is here used in heating oxygen for a ring of longitudinal conduits 75, of increasing diameter until opening at 76. The heating nozzle 65 has an annular narrowing 77 at the location of the transverse groove 55 and at this level are provided with radial perforations 78, so that a downstream part 75 ′ of the conduits 75 is supplied with a combustible mixture.

It is noted that between the housings 56 and 57 of the annular heating body 12 is made a groove 80 which forms an additional heating duct with fuel effect particularly useful when the nozzle is equipped with two inserts forming two cutting jets intervening successively, the intermediate heating thus produced ensuring a resumption of heating in a medium or bottom zone of the groove outlined by the first cutting jet 64.

We note that in both cases, the pre-cut heating is reinforced at 50 and 51 which represents the leading edge of the future cut.

On the other hand, it is noted that the cutting jet 63 which occurs either on a one-off basis after the heating nozzle (FIG. 3) or after the roughing out of the groove made by the cutting jet 64 (FIG. 5) sees its action reinforced by an annular ring of flames 69 supplied with a mixture also with a fuel effect.

The annular ring of oxygen jets opening at the outlet 47 of the conduits 46 at the level of the nozzle fixing nut, has the role of preventing any definitive connection between nozzle and nut which usually can result from metal projections in fusion. The oxygen delivered to this location ensures instant burning, or at least a repelling action, of the splashes of molten metal.

Claims (14)

1. - Steel cutting nozzle with cutting oxygen jet and heating ring around said jet, characterized in that it comprises a nozzle body with two conduits connected to a cutting oxygen supply conduit ending in two housings aligned along a diametrical axis, with a fuel mixture supply means opening at one of said housings, said first housing, said nozzle body being associated with at least one set of three inserts, including two so-called inserts of cutting adapted to engage, one in the first housing with closure of the outlet of the fuel mixture supply means, and communication with the cutting oxygen conduit, the other in the second housing, the third insert being an additional heating nozzle adapted to engage in place of the first cutting insert, in the first housing with establishment of communication of nozzle heating ducts with the supply means tion in combustible mixture. 2. - Cutting nozzle according to claim 1, characterized in that the heating nozzle comprises a head with a cutting oxygen intake duct opening into the said nozzle heating pipes. 3. - cutting nozzle according to claim 1 or 2, characterized in that the nozzle body compresses two bodies engaged one on the other, namely a body of injectors with a core and injector head with a stepped plurality of grooves for supplying gaseous constituents, namely heating oxygen, cutting oxygen, combustible gas, forming an abutment shoulder for an annular body known as heating, with fixing means with determined angular orientation of said annular body heating on said injector body core, said annular heating body incorporating aligned longitudinal heating ducts in alignment with homologous ducts of the injector head, which are connected on the one hand to a duct opening into a groove d fuel supply, on the other hand to a so-called injector conduit opening into a heating oxygen supply groove, the means for supplying combustible mixture to the nozzle heater forming a transverse chamber connected by longitudinal supply pipes for combustible mixture each connected on the one hand to a pipe leading to the supply groove in fuel, on the other hand, to a so-called injector conduit connected to a so-called cutting oxygen supply groove, used here for heating oxygen. 4. - Cutting nozzle according to claim 3, characterized in that the annular heating body extends axially beyond the core with a massive end part having two passages forming end parts of the insert housings, the end face of the core being at a short distance from the interior bottom of the massive end part of the annular heating body, so as to form a transverse annular groove forming said fuel mixture supply chamber, into which open the fuel mixture supply conduits with extension longitudinal. 5. - Cutting nozzle according to claim 4, characterized in that the ducts with longitudinal supply extension opening into the transverse groove between the front face of the core and the bottom of the massive end part of the annular heating body are formed exclusively in the core of the injector body. 6. - Cutting nozzle according to any one of claims 1 to 5, characterized in that the cutting inserts and the heating nozzle have over a part of their axial length a thread cooperating with a corresponding thread of a housing. 7. - cutting nozzle according to claim 6, characterized in that the threads are formed in the conduits-housing the core of the injector body. 8. - Cutting nozzle according to any one of claims 1 to 7, characterized in that a cutting insert has a longitudinal oxygen cutting duct convergent-divergent. 9. - Cutting nozzle according to claim 8, characterized in that a cutting insert has an annular ring of peripheral grooves over a terminal axial length. 10. - Cutting nozzle according to any one of claims 1 to 9, characterized by a set of cutting inserts having identical external mounting configurations and internal oxygen cutting passages of different diameter. 11. - Cutting nozzle according to any one of claims 1 to 7, characterized in that the heating nozzle has, beyond the mounting thread, an extension with reduced section head with seal sealing ring and an axial duct opening into radial conduits. 12. - Cutting nozzle according to any one of claims 1 to 7 and 11, characterized in that the heating nozzle comprises at an intermediate level a narrowing of external diameter with the radial conduits each opening into a longitudinal nozzle conduit. 13. - Cutting nozzle according to any one of claims 1 to 12, characterized in that an intermediate longitudinal duct is formed between the two insert housings of the massive end part of the annular heating body, said duct taking birth at the transverse feed chamber. 14. - Cutting nozzle according to any one of claims 1 to 13, characterized in that the annular heating body has a radially outer extension bearing on a radially outer extension of the injector head of the injector body, with longitudinal conduits aligned through said extensions and opening into the injector head into a groove for supplying heating oxygen.

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