FR2525738A1 - SPARK IGNITION NOZZLE - Google Patents

Abstract

THE SUBJECT OF THE INVENTION IS A NOZZLE WITH SPARK IGNITION. THE NOZZLE CONTAINS AN INTERIOR TUBE 1 AND AN EXTERNAL TUBE 3 ELECTRIC CONDUCTORS, AND AN ELECTRICALLY INSULATING BODY 5. THE TUBE 3 PROJECTS IN FRONT OF THE TUBE 1. THE INNER SURFACE OF THE FRONT END PART OF TUBE 3 AND FRONT END OF THE INNER SURFACE 10 OF THE BODY 5 DEFINE A SKIRT SURFACE 6. THE REAR END 11 OF THE PART OF THE TUBE 3 DEFINING THE SURFACE 6 AND THE FRONT FACE 7 OF THE TUBE 1 CONSTITUTE A PAIR OF ELECTRODES A SPARKS 12, 13. SIDE 7 IS BEHIND THE SIDE 9 WHICH IMPROVES THE RELIABILITY OF IGNITION. APPLICATION TO OXYCUTTING TORCHES.

Description

- 252578

  The present invention relates to a spark-igniting nozzle in which the front end of an inner tube and

  the front end of an outer tube form a pair of electrodes.

  The nozzle of the present invention, although designed to be primarily used on flame cutting torches, may also be used as a nozzle for heating burners (including gas welding burners). This nozzle is equally useful. The choice of the feed gas used with the nozzle is not limiting because different gases can be used depending on the material constituting the outer tube, the length of the skirted surface (that the will be described later) at the front end of the nozzle, the spacing of the electrodes, etc. In order to prevent the projection of flames as in the case of propane burners due to a low rate of combustion, the end the outside tube of the nozzle is generally provided with a skirted surface protruding beyond the front end of the inner tube of the nozzle The diameter and depth of the skirted surface must be r a defined ratio which is a function of the diameter of the supply gas inlet channel and the fluid pressure in

circulation.

  On the other hand, these spark ignition nozzles also include the nozzles whose inner and outer tubes serve as conductors for the spark electrodes In this case, it is necessary to electrically isolate the inner tube from the outer tube by means of a gaseous mixture circulation channel, provided between the two, in order to

  to produce sparks only at the front end of the nozzle.

  The present invention was carried out on the basis of the research carried out on the relative provisions between the skirted surface and the electro-insulating material interposed between the tubes in order to

  fulfill the conditions set out above.

  One of the objects of the present invention is to ensure a good

  ignition by spark taking into account the skirted surface.

  Another object of the invention is to provide a spark ignition nozzle comprising an electrically conductive inner tube and an electrically conductive outer tube, electrically insulated from the preceding one, said outer tube being mounted around the inner tube and protruding forward beyond the inner tube, an electrical insulating member being mounted at least in the front end portion of the outer tube so that its end face is disposed in front of the end face of the inner tube, the inner surface of the inner part of the inner tube the front end of the outer tube and the front end portion of the inner surface of the insulating member defining a skirted surface, the rear end of the front end portion of the outer tube defining the skirted surface and the front side of the inner tube

  constituting a pair of spark electrodes.

  Another object of the invention is also to provide a spark ignition nozzle as above and characterized in that a gas mixture passage channel is provided between the inner tube and the outer tube, the surface interior of the insulating member facing the gas mixture passage channel, the inner tube having a plurality of groove-shaped gaseous mixing passage channels arranged axially in the outer periphery of its

  front end part, and all around it.

  The nozzle of the invention described above can be

  lighted safely, without flames.

  Other objects and advantages of the invention will appear in

  the following description, made with reference to the accompanying drawings in

  FIG. 1 is a partial view in longitudinal section of the end of the nozzle according to a first embodiment. FIG. 2 is a side elevational view of the nozzle, along line II-II of FIG. 1. FIG. 3 is a partial view in longitudinal section of the end of the nozzle according to a second embodiment; FIG. 4 is a side elevational view of the nozzle according to the embodiment of FIG. 3; FIG. a partial view in longitudinal section of the nozzle according to a third embodiment and FIG. 6 is a partial view in longitudinal section of the

  nozzle according to a fourth embodiment.

  The structure common to the four embodiments shown in the accompanying drawings is described with reference to the

Figures I to 6.

  An electroconductive outer tube (3) is mounted on and electrically isolated from an electrically conductive inner tube (1).

  outer tube (3) protrudes forwardly beyond the inner tube (1).

  An electrical insulating member (5) is mounted at least in the front end portion of the outer tube (3) and its end face (9) is disposed in front of the end face (7) of the inner tube (1). of the front end portion of the outer tube (3) and the front end portion of the inner surface (10) of the insulating member (5) define a skirted surface (6). ) of the front end portion of the outer tube defining the skirted surface (6) and the end face (7) of the inner tube (1)

  constitute a pair of spark electrodes (12, 13).

  In the structure described above, the sparks are produced at a location in front of the exit of the gaseous mixture, i.e., forward of the front face (7) of the inner tube so that the gaseous mixture can ignite more safely than? O when sparks are produced in a location exactly coincident with the front (7) or rear (inward)

of it.

  The insulating member (5) which is essential for limiting the location of spark formation only at the end of the nozzle, as indicated above, is suitably arranged so as to cause the formation of sparks in advance of As a result, the structure is simple and convenient to perform. The present invention therefore has the advantage of being able to ensure a

  adequate ignition using a simple structure.

  A first embodiment of the invention will now be described with reference to FIGS. 1 and 2. The provisions of the common structure already described will not be repeated in this way.

description.

  The inner tube (1) and the outer tube (3) are both made of copper. A mixture of propane gas and preheating oxygen is passed through an annular passage channel (4) provided between the tubes (1) and (3) The electrical insulating member (5) is made of ceramic The inner surface (10) of the insulating member (5) faces a portion of the channel (4) constituted by a plurality of grooves (14) formed by machining on the outer periphery of the inner tube (1), and in the axial direction of said tube (1) The grooves (14) are arranged at intervals

  equal on the periphery of the tube (1).

  Although the inner surface (10) of the insulating member and the skirted surface (6) have been shown flush with each other, it is possible to move them relative to one another ,

  inward or outward, radially.

  It is preferable to use a piezoelectric block as a power supply, but it has not been shown although the energy of high pressure cutting oxygen can be used to control the piezoelectric block, alternatively, a mechanical or manual percussion force or a compressive force can also be used. The piezoelectric block can be mounted in the torch or torch head or in the nozzle. In addition to the piezoelectric block, it is also possible to use a battery or power supply

network.

  A second embodiment will now be described in

referring to Figs 3 and 4.

  Several gas mixture passage channels (4) pass through the inner tube (1) over its entire length The insulating member (5) is interposed between the inner tube (1) and the outer tube (3), on

  the whole extent on which these two organs are opposite.

  A third embodiment will now be described with reference to FIG. 5 An annular gaseous mixing channel (4) is formed between the inner tube (1) and the outer tube (3), as in the case of the first embodiment of the invention. embodiment, but the front face of the channel (4) is closed by the insulating member (5). Several gas mixture passage channels (15) communicating with the annular channel (4),

  extend through the front end portion of the inner tube (1).

  FIG. 6 represents a fourth embodiment. The inner tube (1) is subdivided into two tubes, one external (17) and the other internal (16). The inner inner tube (16) and the outer inner tube (17). ) are assembled and an annular gaseous gas passage channel (18) is provided therebetween, except at their front end portions. A plurality of groove-shaped gaseous mixing passageways (19) communicating with the annular groove ( 18) are provided on the outer periphery of the front end portion of the tube

  internal interior (16), in the direction of the axis of said tube (16).

Claims (4)

  1 spark ignition nozzle comprising an inner tube, an outer tube and an electrically insulating member and a gas channel provided between these tubes, characterized in that the inner tube (1) and the outer tube (3) are electrically conductive and electrically insulated from each other, said outer tube (3) being mounted around the inner tube (1) and protruding forwardly beyond the inner tube (1), the insulating member ( 5) being mounted at least in the front end portion of the outer tube (3) so that its end face (9) is disposed in front of the end face (7) of the inner tube (1), the inner surface of the front end portion of the outer tube (3) and the front end portion of the inner surface (10) of the insulating member (5) defining a skirted surface (6), the rear end (11) of the front end portion of the outer tube defining the skirted surface ( 6) and the end face (7) of the inner tube (1) constituting a pair of electrodes to sparks (12, 13).   2 spark ignition nozzle according to claim 1, characterized in that a gaseous mixing passage (4) is provided between the inner tube (1) and the outer tube (3), and that the inner surface (10) of the insulating member (5) faces the gaseous mixing passage (4), the inner tube (1) comprising a plurality of groove-shaped gaseous mixing passages (14) arranged at the outer periphery of the front end portion   of this tube and in the axial direction thereof.   3 spark ignition nozzle according to claim 1, characterized in that the inner tube (1) comprises a plurality of gas mixture passage channels (15) extending at least through its front end part.   A spark ignition nozzle according to claim 1, wherein the inner tube (1) comprises two inner and outer tubes (16, 17) assembled to form a gas passage mixing channel (18) therebetween, and in that the inner inner tube (16) has a plurality of groove-like gas passage passages (19) on the outer periphery of the front end portion and   in the direction of the axis of said tube 16.   Spark ignition nozzle according to any one of   Claims 1 to 4, characterized in that the insulator (5) is ceramic.