FR2527310A1 - PERFECTED NOZZLE WITH SPARK IGNITION - Google Patents

Abstract

TUBULAR SPARK IGNITION NOZZLE CONSISTING OF AN INTERNAL TUBE 1, AN EXTERNAL TUBE 2 AND AN INSULATING BODY 5 FITTED BETWEEN THE TWO, THE FRONT ENDS OF TUBES 1, 2 PROJECTING OUTSIDE BEYOND THE FRONT END OF THE INSULATING BODY, IN THE AXIAL DIRECTION OR OF THE GAS FLOW FROM THE NOZZLE, AN ANNULAR PASSAGE CHANNEL 13 BEING FITTED BETWEEN THE INTERIOR 1 AND EXTERIOR 2 TUBES IN FRONT OF THE INSULATING BODY TO COMMUNICATE WITH THE CHANNELS GAS PASSAGE AXIALS TO THE EXTERIOR PERIPHERY OF THE INTERIOR TUBE. THE INVENTION APPLIES, IN PARTICULAR, TO NOZZLES FOR OXYCUTTING TORCH.

Description

PERFECTED NOZZLE WITH SPARK IGNITION ".

  Invention of Junichi KATAYAMA On behalf of the so-called society: AIR LIQUIDESOCIETE ANONYME FOR

  THE STUDY AND EXPLOITATION OF THE GEORGE CLAUDE PROCESSES.

  The present invention relates to a spark ignition nozzle and in particular to a nozzle which comprises an inner tube and an outer electrically conductive tube whose end ends

  are used as spark electrodes and assembled with inter-

  position of an electrically insulating member with respect to the rear of the electrodes and o the inner tube comprises several axial channels

  groove-shaped gaseous mixture, arranged peripherally

  all around and arranged on the outer peripheral part of

  the front end opposite that of the insulating member.

  Figs 1 and 2 show an example of a conventional nozzle of this type of construction proposed by the applicant (not published). The drawings show the inner tube (1), the outer tube (2), the spark electrodes (3,4) , an electrical insulator (ceramic) (5) and channel-shaped gaseous mixing passages (6)

  inner tube (1) is provided with projections (7), each of which is formed

  two adjacent channels (6, 6) Sparks tend to form

  where the air gap is the smallest.

  a high probability of forming a spark on the conventional nozzle

  Bique between the inner face of the front end (8) of the outer tube (2) and the outer face of the projection (7) of the inner tube (1) Such a spark is shown in (9) for illustration However

  the combustible gas mixture passes through separate channels (6, 6)

  The high probability of spark formation in an area away from the gas discharge zone involves a risk of misfire as the spark is formed at a point where the gaseous mixture is absent (ie term "absent" not before

  not be considered as meaning "totally absent" but as

  to say "at a low concentration") This trend is accentuated

  with the increase of the width T of the projections (7).

  The conventional nozzle has the further disadvantage of having its or-

  insulation (5) in a position far too advanced and consequently

  subject to thermal deterioration. In other words, the frontier

  tale (10) of the insulating member (5) is arranged in front of the part

  (11) of the inner tube (1) and is thus exposed to flames.

  In addition, the distance A from the front end (12) of the outer tube

  (2) at the front (10) of the insulating member is extremely weak, which affects the strength of the member When the front end (12) 1 of the outer tube is heated by the flames and the radiation thermal of the room, the heat is transmitted to the insulating member (5)

  which affects the latter in a prejudicial way since the

tance A is low.

  The present invention has thus been realized to effectively remedy the problems of ignition failure and

  deterioration of the insulating member.

  An object of the present invention is to provide a nozzle

  spark ignition device comprising an inner tube and an outer tube

  electro-conductors, the front ends of which serve

  respectively spark electrodes and are mounted together with the interposition of an electrically insulating member arranged to be at the rear of the electrodes, the inner tube comprising a plurality of axial channels of gaseous mixture passage shaped shaped grooves circumferentially in its outer outer peripheral portion opposite to the insulating member whose front portion is positioned at the rear of the front end of the insulating inner tube and that of the outer tube; an annular channel being formed between the inner tube and the outer tube so as to communicate with the outlets of a plurality of passage channels, so as to be in front of the insulating member and behind the electrodes.

  Other objects and advantages of the present invention

  in the following description o:

  FIG. 1 is an axial sectional view illustrating the example of a conventional nozzle described above, FIG. 2 is a cross-sectional view taken along line II II of FIG. 1; FIG. 3 is a cross-sectional view. axial view of a first embodiment of a nozzle according to the invention, FIG. 4 is a cross-sectional view taken along the axis IV IV of FIG. 3; FIG. 5 is a view in axial section illustrating a second embodiment of a nozzle according to the invention, and, Figs 6 and 7 are views in axial section illustrating

  each a different embodiment of a nozzle according to the invention.

  tion. The construction common to the various embodiments shown in the accompanying drawings will be described first in

referring to Figs 3 to 7.

  The nozzle of the present invention essentially consists of a structure of the type already described with reference to FIGS. 1 and 2 and further comprises the following devices: (a) the electrical insulating member (5) whose front end (10) is arranged at the rear of the front end (11) of the inner tube (1) and the end end (12) of the outer tube (2) and, (b) an annular channel (13) communicating with the outlets a plurality of channels (6) is provided, this channel being formed between the inner tube (1) and the outer tube (2) and disposed in

  front of the insulating member (5) and behind the spark electrodes

the (3, 4).

  Devices (a) and (b) have certain characteristics

  during operation and certain characteristics

  the following: (i) At any location on the periphery, a

  spark can penetrate between the inner tube (1) and the outer tube

  (2) where the gas mixture invariably lies.

  has a significantly higher probability of infliammation than in the case of the conventional device since the peripherally subdivided gas mixture flows meet in the annular channel (13) mentioned above in (b) and then exit in the form of 'a stream

annular.

  (ii) Flammability is not essentially controlled

  by the width T of the projections mentioned above.

  (iii) Considering the conventional device, the annular channel (13) can be considered simply constituted by a

  moving the insulating member (5) backwards, so by creating

  a space at the place where the front part of the insulating member (5) is arranged in a conventional manner so that this space can serve as an annular channel (13) Se annular channel is thus much easier to

  realize for example that if it is machined by cutting a part in-

  wall of the insulating member (5) in the conventional position

  than. (iv) The front end of the insulating member (5) is 1 at a greater distance from the front of the outer tube (2) than in the conventional device. Furthermore, there is an annular channel (13), that is to say a space at the front of the insulating member (5) The mixture

  low temperature gas which circulates continuously in this space.

  it has a much lower thermal conductivity than the material

  (conductor) of the outer tube (2) The insulating member (5) is therefore doubly

  adequately protected against heat.

  the present invention therefore has the following advantages: the nozzle is of simple construction, it is very easy

  to manufacture and, moreover, its flammability is appreciably improved.

  while providing total protection of the insulating member.

  the embodiments of the present invention will

  now be described below.

  In the first embodiment (see Figs 3 and 4),

  an inner tube (i), an outer tube (2), electrodes

  spark arresters (3, 4), an electrically insulating member (5) made of ceramic or the like, groove-shaped circulation channels (6) for a combustion gas mixture (C 3 H 8 + O 2), a channel ring (13)

  and a cutting oxygen passage channel (14).

  The annular channel (13) comprises a triangular portion -

  rear large diameter and a small diameter front part.

  This embodiment differs from that of Fige 5 and 6 described later in that the front (11) of the inner tube (1) comes

  flush with the front (12) of the tube (2).

  the inner tube (1) and the outer tube (2) are connected

  to a feed (not shown) consisting of a piezo block

  electrical housed in a torch head.

  In the second embodiment (see FIG.

  poured from the first, the front (11) of the inner tube (1) is disposed at the rear of the front (12) of the outer tube (2) and has been provided a

  annular passage channel (13) composed of a rectangular portion

  and a triangular front part.

  Apart from these characteristics, the second form of

  is essentially similar to the first The parties or

  areas designated by the same benchmarks are those of the first

realization.

  In the other embodiments (see FIGS. 6 and 7), each of them has an annular passage channel (13) plus

  simple as in the first or second embodiment Cha-

  that portion or portion shown is designated by the same mark as that of the first embodiment.

PEVEIDICATIONS

  1 1 spark ignition nozzle comprising an integral 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 (2) are electrically conductive, their front ends serving as spark electrodes (3, 4)

  respectively, and are mounted together with an insulating member (5) between

  placed between the two At the back of the electrodes (3, 4), in that the inner tube (1) comprises a plurality of groove-shaped gaseous mixture axial passage channels (6) arranged on the front of its

  outer peripheral part opposite the insulating member (5) and

  placed peripherally all around it, in that the front end of the insulating member (5) is disposed at the rear of the end

  of the inner tube (1) and the end of the outer tube

  (2), and that an annular passage channel (13) communicates

  as with the outputs of the plurality of passage channels (6) is

  arranged between the inner tube (1) and the outer tube (2) and posi-

  at the front of the insulating member (5) and behind the electrodes

with sparks (3, 4).

  2 spark ignition nozzle according to claim 1,

  characterized in that the insulating member (5) is made of ceramic.