EP0378461B1 - 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 present invention relates to a steel cutting equipment with cutting oxygen jet and heating ring around said jet.

The cutting nozzles commonly used in the steel industry for flame cutting of large thicknesses hot, 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.

Document FR-A-2,602,309 proposes a new design of injectors for supplying oxygen to the central heating ring and an embodiment in two parts of this cutting nozzle, thus making it possible to optimize the output speeds of the heating gas, while offering the user the advantage of only changing the cutting block in the event of an incident leading to the 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, and a heating ring located between this external ring and the central cutting jet, with a very combustible flame, to obtain a long plume around the cutting jet which, entrained by the latter, partly enters the groove cutting and helping 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 groove, which results, especially in flame cutting. cold, scouring detrimental to the quality of cut.

This is the reason why the document FR-A-2.613.264 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 in the raw cutting groove, which was made by the first jet of oxygen and which is finished with 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 groove associated with two high-pressure cutting oxygen jets made it possible to increase the cutting speed by 20% when cold and 10% when hot, by compared to the most efficient conventional single-jet processes.

• comme la réalisation du conduit de coupe, et en particulier l'usinage de la tuyère de Laval, est un élément déterminant pour obtenir de bonnes performances (largeur de saignée et vitesse de coupe), cette réalisation est délicate et coûteuse, compte tenu de la dimension des buses actuellement commercialisées, et l'invention vise une simplification de cette opération ;
• d'autre part, l'utilisateur du matériel est actuellement obligé de posséder deux types de buses selon qu'il veut privilégier la vitesse de coupe (buse à deux jets de coupe) ou la largeur de saignée (buse à jet de coupe unique), et l'invention vise à réunir ces deux fonctions dans une seule et même buse ;
• enfin, par expérience, la durée de vie d'une buse de coupe est directement liée, dans des conditions normales d'utilisation, à la durée de vie du conduit de coupe. Avec les conceptions actuelles, on est obligé, en cas de chute de performances, quand elles sont observées après nettoyage de la buse, de changer soit le bloc de coupe dans la version à jet unique, soit la buse complète dans la version à deux jets, et l'invention vise à limiter encore les pièces à changer.

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 dimension of the nozzles currently sold, and the invention aims to simplify this operation;
• on the other hand, the user of the equipment 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 a single nozzle;
• finally, by 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 equipment according to the present invention is characterized in that it comprises a nozzle body with two conduits connectable to a cutting oxygen supply conduit, ending in two housings aligned along a diametrical axis, with a means supply of fuel mixture opening at one of the housings, said first housing, and at least a 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 called 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, 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 assembled 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;
• FIG. 7 is a cross-sectional view along line VII-VII of FIG. 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 pipes 4 'and 4' ', and a fuel supply pipe 5.

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

• A la périphérie une pluralité annulaire (huit au dessin) de conduits longitudinaux 21, dits de propreté, partant de la chambre transversale d'alimentation en oxygène de chauffe 16 et débouchant tous au travers d'un épaulement 22 de bloc d'injecteurs 11 ;
• deux conduits longitudinaux dits de préchauffe 23 et 24 alimentés en combustible via un conduit 25 partant de la chambre de combustible 14 et via un petit conduit à injecteur 26 partant de la chambre annulaire en oxygène de chauffe 16 et débouchant tous au travers d'un épaulement 22 du bloc d'injecteurs 11 (cf. figures 1,3, 5 et 8) ;
• une pluralité annulaire (seize au dessin) de conduits dits de chauffe 28 inclinés vers l'extérieur et vers l'aval, alimentés en oxygène par un conduit à injecteur 29 partant de la chambre annulaire d'oxygène de chauffe 15 et par un conduit 30 partant de la chambre annulaire de combustible 14 et débouchant tous au travers de l'épaulement 22 du corps d'injecteurs 11 ;
• intercalées entre certains conduits de la couronne de conduits de chauffe 28 sont agencés (cf. figure 2) une pluralité annulaire de conduits de chauffe carburante 31 raccordés via un conduit 32 à la chambre d'alimentation en combustible 14 et via un conduit 33 à injecteur 34 partant de la chambre d'alimentation en oxygène de chauffe 16. Ces conduits de chauffe carburante 31 sont longitudinaux et, contrairement aux conduits de chauffe 28, qui, inclinés vers l'extérieur, débouchent au travers de l'épaulement amont 22, se prolongent dans une partie aval en forme de noyau 35 du corps d'injecteurs 11 jusqu'à déboucher au travers d'une face frontale terminale 36 de ce corps d'injecteurs 11 ;
• le conduit d'oxygène de coupe 18 se subdivise en deux conduits 37 et 38, dont les axes sont dans un plan diamétral moyen entre les conduits de préchauffe 23 et 24 et débouchant au travers de la face frontale 36.

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. Figures 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 emerging through the shoulder 22 of the injector body 11;
• interposed between certain conduits of the crown 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 with 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, are 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 body 12 has a radially outward flange 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. A piece of cutting equipment for the steel industry having a jet of cutting oxygen and a heating collar around said jet, characterised in that it comprises a nozzle body (11) with two conduits (37, 38) that can be connected to a conduit supplying cutting oxygen (3) and ending in two recesses (56, 57) aligned along a diametral axis, with a means (14, 55) for supplying a fuel mixture leading out into the region of one of the recesses (56) known as the first recess, and at least one set of three inserts (63, 64, 65), two of which inserts, described as cutting inserts (63, 64), being designed to engage, one in the first recess, blocking the outlet of the means for supplying a fuel mixture and communicating with the cutting oxygen conduit, the other in the second recess (57), the third insert being an additional heating nozzle (65) designed to engage, in place of the first cutting insert, in the first recess and establish a communication between the nozzle heating conduits (75) and the means for supplying a fuel mixture.
2. A piece of cutting equipment according to Claim 1, characterised in that the heating nozzle (65) comprises a head (70) with an inlet conduit for cutting oxygen (72, 73) communicating with the nozzle heating conduits.
3. A piece of cutting equipment according to Claim 1 or 2, characterised in that the nozzle body (11) comprises two bodies engaged one on top of the other, namely an injector body (11) having a core and injector head with a plurality of stepped channels supplying gaseous constituents, namely heating oxygen, cutting oxygen, fuel gas, forming an abutment shoulder (22) for an annular body described as a heating body (12), with fastening means (43) determining a given angular orientation of the annular heating body to the core of the injector body, the annular heating body incorporating aligned longitudinal heating conduits in alignment with homologous conduits of the injector head, which are connected on the one hand to a conduit leading into a fuel supply channel (14), and on the other hand to what is known as an injector conduit leading into a supply channel for heating oxygen (16), the means for supplying a fuel mixture for the heating nozzle (65) forming a transverse chamber (55) supplied by longitudinal conduits for supplying a fuel mixture, each one connected on the one hand to a conduit leading to the fuel supply channel and on the other hand to what is known as an injector conduit connected with the channel (16) supplying what is known as cutting oxygen, used here as heating oxygen.
4. A piece of equipment according to Claim 3, characterised in that the annular heating body extends axially beyond the core with a solid end portion having two passages forming end portions of the insert recesses (56, 57), the front end face of the core being a short distance away from the inner base of the solid end portion of the annular heating body, so as to form a transverse annular channel (55) forming the chamber supplying a fuel mixture, into which lead the conduits supplying a fuel mixture, extending longitudinally (31).
5. A piece of equipment according to Claim 4, characterised in that the longitudinally extending supply conduits leading into the transverse channel (55) between the front face of the core and the bottom of the solid end portion of the annular heating body are arranged exclusively within the core of the injector body (11).
6. A piece of equipment according to one of Claims 1 to 5, characterised in that the cutting inserts (63, 64) and the heating nozzle (65) have on one portion of their axial length a thread cooperating with a corresponding internal screw thread of a recess.
7. A piece of equipment according to Claim 6, characterised in that the internal screw threads are formed in the recess conduits (58, 59) of the core of the injector body (11).
8. A piece of equipment according to one of Claims 1 to 7, characterised in that a cutting insert (63, 64) has a longitudinal convergent/divergent-type oxygen conduit (67).
9. A piece of equipment according to Claim 8, characterised in that a cutting insert (63, 64) has, over an axial length at one end, an annular collar of peripheral grooves (69).
10. A piece of equipment according to one of Claims 1 to 9, characterised by a set of cutting inserts (63, 64) having identical outer mounting configurations and inner passages for cutting oxygen, with different diameters.
11. A piece of equipment according to one of Claims 6 or 7, characterised in that the heating nozzle (65) has, beyond the mounting thread, an extension with a head of smaller section (70) having an O-ring seal (71) and an axial conduit (72) leading into radial conduits (73).
12. A piece of equipment according to one of Claims 1 to 7 and 11, characterised in that the heating nozzle (65) comprises at an intermediate level a narrowing of outer diameter (77) with the radial conduits (78) each leading into a longitudinal nozzle conduit (75).
13. A piece of equipment according to one of Claims 4 to 12, characterised in that an interposed longitudinal conduit (80) is provided between the two insert recesses (56, 57) of the solid end portion of the annular heating body, said conduit originating in the region of the transverse supply chamber.
14. A piece of equipment according to one of Claims 1 to 13, characterised in that the annular heating body (12) has an radially external extension of the injector head (11) of the injector body, with longitudinal conduits aligned across said extensions and leading, in the injector head, into a channel for supplying heating oxygen (16).

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