IGNITION DEVICE FOR LANCES

Abstract: An ignition device for lances, such as lances intended for supplying oxygen gas to metallurgical processes, comprising a tubular casing (1) which is intended to be fitted partially onto one end (2) of the lance and the end part (4) of which located distal from the lance carries a striker (5) which includes a pyrotechnical delay (6) that extends into the casing, and a reaction mass (7) which is arranged in the casing and which can be ignited by the striker. The ignition device is particularly characterized by an end stop (9) located in the casing adjacent the reaction mass (7), the end (2) of the lance being intended to be brought into engagement with the end stop when fitting the device.

Description: Ignition Device for Lances. The present invention relates to a lance ignition device, such as lances of the kind which are intended for supplying gaseous oxygen to metallurgical processes, said device including a tubular casing which is intended to be fitted to one end of a lance and which carries a striker equipped with a pyrotechnical delay which extends through the casing, and further including a reaction mass located in the casing and intended for ignition by the striker. Ignition devices essentially of this kind are known to the art. One serious problem with these known devices resides in the prevention of mechanical activation of the reaction mass and of the striker by the lance, and also in ensuring that the reaction mass and the striker will not be dislodged from the casing when fitting the device to the lance. The known devices are also vulnerable in other respects. For instance, the striker or corresponding device is liable to fractural damage or some corresponding damage, resulting in the formation of discontinuities and therewith causing an initiated ignition process to abort. Unless properly controlled, the reinstatement of an aborted ignition sequence can result in uncontrolled ignition of the oxygen gas and therewith constitute a serious safety risk. These problems are, of course, particularly accentuated in such industrial environments as those in which the working tempo is particularly high and the handling of this kind of material is, perhaps, clumsily carried out. The present invention relates to an ignition device which substantially eliminates the above mentioned problems and which, in other respects, is constructed in a particularly suitable manner. The present invention thus relates to an ignition device which is intended for lances, βuch as those intended for supplying oxygen gas to metallurgical processes, and which comprises a hollow tubular casing which is intended to be fitted partially onto one end of the lance and the end part of which remote from the lance carries a striker having a pyrotechnical delay which extends into the casing,and which further comprises a reaction mass which is located in the tubular casing and capable of being ignited by the striker. The inventive ignition device is particularly characterised by an end stop which is mounted in the tubular casing at a location adjacent the reaction mass and against which one end of the lance is intended to be brought. The invention will now be described in more detail with reference to an exemplifying embodiment thererof illustrated in the accompanying drawing, in which: Figure 1 illustrates schematically a first embodiment of an inventive device, where half of the tubular casing has been removed and the device is seen perpendicularly to the direction of its axis. In Figure 1, the reference 1 identifies a substantially tubular and cylindrical casing, which is preferably made of steel. The casing is intended to be fitted partially onto a lance end portion 2, shown in broken lines in Figure 1, the casing having an open end 3 for this purpose. The casing end 4 r which is intended to be distal from the lance 2, carries a striker 5 for ignition of a reaction mass 7 located in the casing, through a pyrotechnical delay 6 extending into the casing. The reference 8 identifies a substantially band-like metal strip which extends from the open end 3 of the casing through which the lance end is inserted and terminates essentially adjacent the reaction mass, at which location a part 9 of the strip or band extends substantially at right angles to the long axis of the casing such as to form an end stop 9. In the case of the illustrated embodiment, the strip 8 extends is attached to the open end 3 of the casing by means of a substantially U-shaped part 10, which embraces an edge part 3* of teh casing at said open 3 thereof. In the case of a preferred embodiment, the metal strip 8 extends from a casing part, e.g. the casing part 10, located adjacent the open casing end, and passes inwardly towards the centre axis of said casing and then substantially along said axis, whereafter the strip is turned substantially transversally to said axis to form an end stop. The striker 5 comprises as a unit an ignition charge 11 and the aforesaid delay 6 and is fastened to the casing with the aid of an end wall piece 12, from which the ignition charge 11 protrudes and through which the delay 6 passes into the casing, said delay preferably extending in a metal tube 13, shown in broken lines in Figure 1, preferably an aluminium tube, 5 therewith to provide mechanical protection for the delay. In the case of the illustrated embodiment, the reaction mass 7 is comprised essentially of metal powder, preferably aluminium powder, and is contained in a container, such as a thin plastic bag 14, which is located adjacent 10. the end 15 of the delay in the casing. The container will preferably be located contiguous with the end 15 of the delay without being attached thereto, the casing having provided therein a protecting and fixating filling material 16, such as cotton 16. 15 The modus oσerandi of the inventive ignition device will be understood in all essentials from the above description of said device. Thus one end 2 of a lance is inserted into the casing end 3, wherewith the metal strip 8 will be sprung to one side to some extent against an inherent spring force, as indicated by the arrows 17, and will hold the ignition device 0 securely subsequent to fitting the device to the lance. The lance cannot be inserted into the casing further than the end stop 9 and cannot therefore be made to push out the striker etc. Because of the springiness of the metal strip, the same ignition device can be used in connection with lances of relatively great diameter interval. In this respect, the inner 5 diameter or like transverse dimension of the casing is such that the casing is able to accommodate a relatively wide range of conventionally occurring lance diameters. The ignition charge is ignited against the striker, whereupon the delay burns into the reaction mass and is able to ignite the protective material and the reaction mass, and in appopriate 0 cases, also the tube through which the delay extends. Combustion takes place while consuming oxygen, and oxygen gas can hence be supplied through the lance. The end 2 of the lance is subsequently ignited, primarily by the reaction 5 mass, and the lance can be kept burning. By using a striker of the aforedescribed kind, fitting is facilitated, the delay is protected and the device is able to withstand rough handling. The reaction mass arrangement also facilitates fitting of the device and contributes to the impact durability thereof. As will be understood from the aforegoing, the inventive arrangement provides a well adapted ignition device which is extremely safe in operation. The invention has been described in the aforegoing with reference to an exemplifying embodiment thereof. It will be understood, however, that other embodiments and minor modifications are conceivable without departing from the scope of the inventive concept. Preferably, the striker is made of a plaBtics material, the delay and tube extending through a plastics jacket 18 and the ignition charge being located outside said jacket. The tubular casing is, of course, not restricted to a circular cross- sectional shape, but may be given some other shape in cross-section. Neither need the metal strip 8 have the form of a band, but may have the form of a wire or some other form. The strip 8 may alBO be attached to the casing in some other manner than through the U-shaped part, e.g. as by welding or adhesive bonding.

Claims: Claims 1. An ignition device for lances, such as lances intended for supplying oxygen gas to metallurgical processes, comprising a tubular casing which is intended to be fitted partially onto one end of a lance and with which the end part that is to face away from the lance carries a striker which has a pyrotechnical delay which extends into the casing, and a reaction mass which is located in the casing and ignitable by said striker, c h a r a c t e r i z e d i n t h a t provided in the casing (1) at a location adjacent the reaction mass (7) is an end stop (9) against which one end (2) of the lance is intended to be brought. 2. A device according to claim 1, c h a r a c t e r i z e d i n t h a t the end stop (9) is formed by a substantially strip-like metal element (8) which has a given springiness and which extends from the open end (3) of the casing (1) into which the lance is intended to be inserted and terminates essentially adjacent the reaction masB (7), and in that the end stop (9) is formed by a part (9) of the strip-like metal element (8) which extends transversally to the direction of the axis of the casing (1) . 3. A device according to claim 2, c h a r a c t e r i z e d i n t h a t the strip-like element (8) is attached to the open end (3) of the casing (1) by means of a substantially U-shaped part (10) which embraces an edge part (3*) of the casing at said open end. 4. A device according to claim 2 or 3, c h a r a c t e r i z e d i n t h a t the strip-like element extends from a part thereof located at the edge of the open casing end (3) inwardly towards the centre axis of the casing and then substantially along said axis and then substantially transversally to said axis such as to form the end stop (9 ) . 5. A device according to claim 1, 2, 3, or 4, c h a r a c ¬ t e r i z e d i n t h a t the striker (5) includes as a unit an ignition charge (11) and said delay (6), and in that the striker (5) is secured in the casing by means of an end wall piece (12) from which the ignition charge (11) protrudes and through which the pyrotechnical delay extends into the casing, said delay preferably extending through a metallic tube (13), preferably an aluminium tube (13). 6. A device according to claim 1, 2 , 3, 4 or 5, c h a r a c - z e d i n t h a t the reaction mass (7), preferably in the form of a metal powder, is contained in a thin plastics container (14), such as a bag (14), which is located adjacent the end (15) of the delay (6) in the casing. 7. A device according to claim 6, c h a r a c t e r i z e d i n t h a t the container (14) is placed contiguous with the delay end (15) without being attached thereto, and in that protective and fixating filling material (16), such aβ cotton wool, is arrranged in the casing. 8. A device according to any one of the preceding claims, c h a r a c t e r i z e d i n t h a t the inner diameter or like dimension of the casing is such as to be able to accommodate a relatively wide range of conventionally occurring lance diameters, the aforesaid springiness of the strip-like element assisting in the adaptation of the device to the diameter of the lance.

Inventors: LARSSON ARNE, LARSSON, ARNE
Applicants: OXY TUBEN AB, OXY-TUBEN AB
Application year: 1988
Main classification: E21B7
IPC codes: E21B7, F27D23