FR2525739A1 - SPARK IGNITION TYPE TORCH - Google Patents

Abstract

A PIEZO-ELECTRIC ELEMENT 18 HELD IN THE HEAD 6 OF THE TORCH IS PUNCHED BY A PUNCH 19 WHEN THE CUT OXYGEN SUPPLY IS OPENED. THE ANVIL 25 IS CONSTITUTED BY PART OF THE HEAD, FOR EXAMPLE BY A CAP CLOSING THE HOUSING CAVITY OF THE PIEZO-ELECTRIC ELEMENT. APPLICATION TO OXYCUTTING TORCHES.

Description

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  SPARK IGNITION TYPE TORCH

  The invention relates to a spark ignition type torch or torch and, more particularly, to the present invention. in particular, to a torch comprising a head on which can be mounted a spark ignition nozzle and which is provided with a piezoelectric block fixed in position and a corresponding striker. In torches of this kind, a kinetic energy is applied to the firing pin to bring it abruptly into contact

  of percussion with a first contact member of the piezoelectric block

  the other contact member is held at the back.

  Due to this percussion contact, the piezoelectric block generates an electromotive force, which is applied to the front end of the nozzle to produce a spark at that end and to ignite a mixture of flowing combustion gases. by

the end of the nozzle.

  Although it was proposed to use the pressure of

  cutting oxygen as the kinetic energy of actuation of the percussion

  it is also possible to use a mechanical shock or a manual effort, alternatively the present invention covers

any of these cases.

  The Applicant has already proposed spark ignition torches where the rear end of the nozzle served as a percussion support for the piezoelectric block (see FIGS. 1 and 2). The piezoelectric block is represented in (18), a striker. in (19), the

  torch head in (6) and the nozzle in (1) The nozzle (1) is subdivided

  The inner tube (31) is electrically insulated from the outer tube (32) by an insulator or an air gap, with the exception of an inner tube (31) and an outer tube (32).

  end of the nozzle or are provided with spark electrodes.

  those (2, 3) The piezoelectric block (18) is provided with an electrode

  (70) electrically connected to the spark electrode (3) by the

  intermediate the torch head (6), a lock nut (12) and the outer tube (32) Another electrode (71) is connected to the spark electrode (2) via the inner tube

(31).

  The direction of percussion and that of the axis of the nozzle

  in the case of the torch of Fig 1 or are perpendicular to

  2 in each case, the rear portion of the inner tube (31) of the nozzle serves as a percussion support (72) of the piezoelectric block (18) This support (72)

  also serves as an input electrode (43).

  Since the nozzle (1) is replaced by a new nozzle when it is worn, it can be separated from the torch head (6). However, as the power supply part comprises the piezoelectric block (18) and - "input electrode (43), the nozzle (1) is associated with the torch head (6) because the block (18) is part of the head of the light (6) and the electrode (43) is

part of the nozzle (1).

  It follows that the assembly of the parts as well as their

  The machining requires a very high precision.

  conventional cylinders are subject to gas leakage or insulation failure when the inner tube (31) of the nozzle is offset from the outer tube (32) of the nozzle as a result of repeated percussion ( torch of Fig 1), or when the percussion carrier (72) of the inner tube (31) is deformed under

  the effect of the percussion (torch of Fig 2).

  Another problem resides in the fact that the percussion reaction causes a partial separation of the input electrode (43) from the electrode (71) of the piezoelectric block (18), which results in the formation of tiny sparks between these electrodes

  and a drop in energy of the sparks between the electrodes (2, 3).

  Torches of this type are also subject to another problem that arises when the torch is operated for ignition, when the nozzle is removed from the head. In this case, a spark springs between the power supply electrodes and, in the presence of combustible gas, ignites the latter, which may cause ignition or accidental explosion

in the torch head.

  The cause of this accident will be described generally with reference to Figs. 3 and 4. Fig. 3 is a schematic view of the circuit in question when the nozzle is in position, while

  Fig 4 is a diagram of the same circuit when the nozzle is raised.

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  ZO is the resistance of the nozzle, ie the total resistance between the spark electrodes and the input electrodes (between 2 and 4, and between 3 and 5) Z 1 is the resistance between the electrodes

  with spark (2,3) Z 2 is the resistance between the power terminals

  (7, 8) of the torch head (6) Z1 and Z2 can be

  considered as corresponding to an energy discharge gap.

  A power supply is indicated in (109).

  In the assembly of FIG. 3, the voltage V of the power supply

  tation (109) is determined so as to produce a spark between the electrodes (2, 3), taking into account ZO + Z 1 The terminals (4, 7) are connected together, as well as the terminals (5, 8). entehdu, there is no spark between the terminals (4,7)

or (5.8).

  However, ZO resistance no longer exists in the world.

  As a result, a voltage higher than the voltage across the terminals of the electrodes (2, 3) of FIG. 3 is therefore not applied to the voltage drop due to ZO in FIG. terminals (7, 8), which are separated from the terminals (4, 5) In the conventional arrangement, this voltage is greater than the potential difference corresponding to an air gap allowing

  the discharge, and therefore produces a spark between the terminals (7, 8).

  Conventional torches also have another problem, which will be described with reference to FIG. 5. A nozzle (1) comprises an inner tube (31) and an outer tube (32), all of which are electrically conductive. sparks are indicated at (2, 3) and the inlet terminals at (4, 5) The nozzle is attached to a torch head (6) by a clamping nut (12) The chainfine head (6) and the nut (12), both electrically conductive, are connected

  to a first electrode of the piezoelectric block (18).

  The other electrode of the piezoelectric block (18) is

  electrically connected to the rear end of the inner tube (31) by direct contact therewith An electrical insulating member, shown at (10), is disposed between the inner tube (31) and the torch head (6), while that the striker of the block (18) is

represented in (19).

  The striker (19) is brought into percussion contact on the piezoelectric block (18) by a gas pressure to generate

  an electromotive force When the gas supply is inter-

  broken, the firing pin (19) is biased by a spring (22) and a magnet (24) The latter is attracted to a magnetic valve seat (23) to close the valve The block (18) must be provided with a gas channel (50) The rear end of the inner tube

  (31) must also have a similar channel (51).

  In the conventional torch that has been described, the locknut (12) is tightened to maintain the input terminal (5) of

  the rear end of the inner tube (31) in contact with the elec-

  piezoelectric block trode (18) If the nut is not suitable-

  tightness, for example as a result of errors in ratings between the bodies concerned, a faulty contact occurs, which

  that the current no longer passes to the spark electrode (3), to the ex-

  tip of the nozzle, or that very small sparks occur in the contact area These small sparks cause a drop in spark energy to the electrodes (2, 3) or even sparks, which increases even more wear of the surfaces of

contact.

  When, on the contrary, the nut (12) is tightened excessively-

  in order to ensure adequate contact, the piezoelectric block

  (18) or insulation (10) may be damaged.

  The classic torch also has a disadvantage

  additional, namely that the channel (50) makes its structure complex.

  The main object of the present invention is to realize

  a spark ignition type blow torch with an adaptable spark ignition nozzle torch head, that head having a piezoelectric block fixed in position and a corresponding striker, and a percussion holder or anvil for the block

  piezoelectric is part of the torch head.

  Another object of the present invention is to provide a torch where the percussion-supporting member applied to the piezoelectric block is part of the torch head, where the nozzle is provided with spark electrodes at its front end and terminals. entrance at the back, where the torch head is equipped with

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  power supply terminals that can be connected to the input terminals by inserting the nozzle into the torch head, and where the disruptive distance between the power supply terminals is greater than the gap allowing discharge when the nozzle is removed from the torch head. Another object of the present invention is to provide a torch where a piezoelectric block-printed percussion support member is part of the torch head, where an electrical insulating element defines a gas flow channel between a surface inner peripheral of the head and said insulator and is arranged around a helical spring for connecting one of the power supply terminals of the head, made of electrically conductive material, to the nozzle input terminal corresponding to this terminal, and o a

  passageway is formed between the insulating element and the nozzle or in the

  insulating itself to maintain the gas flow channel

  in communication with a gas flow channel provided in the nozzle.

  The present invention overcomes all the disadvantages

  conventional torches described above.

  Other objects and advantages of the invention will become apparent

  of the following description with reference to the accompanying drawings

  Figs 1 and 2 are cross-sectional views illustrating prior art blowtorches. Figs 3 and 4 are circuit diagrams illustrating a problem presented by the prior art;

  Fig 5 is a sectional view showing another trawl

  the art of the prior art; Figs. 6 and 7 are sectional views showing an embodiment of the present invention; Figs. 8 and 9 are partial sectional views showing modifications of the embodiment of Figs. 6 and 7; Fig. 10 is a partial sectional view illustrating another embodiment; and Fig. 11 is a partial sectional view showing a

  modification of the embodiment of FIG.

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  It will now proceed to the description of a

  embodiment of the invention with reference to FIG.

  The torch head (6) is provided internally with a -

  insulating member (10) in the form of a frustoconical tube, pressed against the head (6) by a fixing nut (11) A nozzle (1) is

  inserted into the torch head, in contact with the insulating organ

  lant (10), and fixed in position by a locking nut (12) can be seen in (13) a fuel gas port, in (14) an orifice

  preheating oxygen passage and in (15) a pressure port

  The insulating member (10) is provided with holes (16) and (17) communicating respectively with the orifices (13) and

  (14) A piezoelectric block (18) and a firing pin (19) correspond to

  are housed in a cavity (9), that is to say in an enlarged channel (20) for cutting oxygen.

  intermediate support for supporting a compression spring

  (22) and the piezoelectric block (18) The striker (19)

  is pressed against a valve seat (23) by the spring (22).

  A magnet (24) attached to the striker (19) is held in the attraction position against the valve seat (23), which is made of a

  magnetic material A cap (25) provided with an O-ring seal

  around the cheek (26) is screwed into the torch head (6) and comes into contact with a contact member (27) which constitutes one of the electrodes of the block (18). organ

  percussion support, that is to say anvil.

  The casing (casing) of the piezoelectric block (18) is made of an electrical insulating material A tube (29) surrounding a flat electrode (28) which constitutes the other electrode of the block (18) forms an integral part of the casing. to protrude

  it is perpendicular to the block (18).

  A helical spring (30) made of electrically conductive metal is screwed into an inner tube (31) and is therefore attached to the

nozzle (1).

  A clearance is provided between the tube (29) and the periphery

  inside (34) of the head to define the orifice or oxy-light

  cutting gene (15), as well as between the insulating member (10) and the tube (29) The cutting oxygen is fed through a channel (35) surrounding the

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  striker (19), by a channel (36) arranged in the support member

  intermediate (21), then by the aforementioned games.

  It goes without saying that the inner tube (31) is isolated

  electrically of an outer tube (32) by a game or an insulator.

  The inner tube (31), made of conductive metal such as copper for example, electrically connects the coil spring (30) to a spark electrode (2). The outer tube (32), which is also made of copper or a material like conductor, electrically connects the head (6) to a spark electrode (3) by

  through the locking nut (12).

  When the fuel gas and oxygen arrivals are

  open, the pressure of oxygen acts on the firing pin (19).

  When the oxygen pressure reaches a level exceeding the attractive force (Coulomb force) between the magnet (24) and the valve seat (23), the magnet (24) instantly separates from the seat (23). ) As a result of the arrival of the cutting oxygen flow, the

  striker (19) strikes a contact member (37) of the piezo block

  electrical (18), so that the piezoelectric elements of the block (18) generate an electromotive force which is applied to the front end of the nozzle (1) to produce a spark between the electrodes (2, 3) of the tip of the nozzle The spark ignites the combustible gas mixture that is already flowing out of

the end of the nozzle (1).

  The percussion support, that is to say the cap (25), supports the percussion force applied by the striker (19) on

  the block (18) This force does not act directly on the tube

laughing (31) of the buie.

  When the oxygen supply is interrupted when it is desired to stop using the torch, the spring (22) recalls the striker (19), which allows the magnet (24) to be attracted to the

valve seat (23).

  The spring (30) is intended to provide the electrical connection

  between the inner tube (31) and the flat electrode (28) when

  the nozzle (1) is fixed on the torch head (6).

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  It is also useful to modify the present embodiment as follows: (i) The cap (25) is an integral part of the main body of the torch head (6) and serves as a percussion support.

  (ii) The form of realization in question may be

  either as a manual torch or as an automatic torch.

  It can be modified for use in cutting, welding or machining.

  (iii) The percussion direction on the piezo block

  electrical (18), which is perpendicular to the axis of the nozzle (1), can be inclined or intersect this axis at an appropriate angle

  different, or be parallel to or coincide with that axis.

  (iv) A manual or mechanical force may be exerted instead of the oxygen pressure as the percussion energy of the

block (18).

  (v) The two piezoelectric elements used in the block (18) of Fig. 6 can be replaced by a single element. In other words, the torch of FIG. 6 has the following advantages: The casing (casing) of the piezoelectric block (18) is made of electrical insulating material, and the tube (29) which surrounds the flat electrode (FIG. 28) constituting the second electrode of the block (18), that is to say the power supply terminal (8), is an integral part of the housing and projects thereon perpendicular to the block (18) The insulating tube (29) serves

  ensure a sufficient "disruptive distance".

  The helicoidal spring (30) of electrically conductive metal is screwed into the inner tube (31) and is thus fixed to

  the nozzle (1) The spring (30) corresponds to the input terminal (5).

  It is in contact with the flat electrode (28), that is to say with the power supply terminal (8) The outer tube (32) comprises a portion (33) in contact with the clamping nut (12) and corresponding to the other input terminal (4) The torch head (6) comprises a portion (33 ') in contact with the nut (12) and electrically connected to the contact member or electrode (27) of the block (18) via the cap (25) This part (33 ') corresponds

  at the other power supply terminal (7).

  The inner tube (31) is of course electrically insulated

  outer tube (32) by an insulating material or

  This tube (31) is made of copper or a similar conductive material and electrically connects the terminal (5) to the electrode (3). This is true

  also for the outer tube (32).

  It will now be assumed that the tightening nut (12) is removed to disassemble the nozzle (1) from the torch head (6). The spring (30) attached to the nozzle (1) is disassembled at the same time ( see Fig 7) If the cutting oxygen valve is open at this time, the firing pin (19) is rapidly brought into percussion contact with

  the block (18) under the effect of the pressure of the oxygen, which provokes

  that the creation of an electromotive force by the piezoelectric elements

  However, the large disruptive distance provided by the electrical insulating tube (29) prevents the discharge; the voltage created undergoes self discharge as a result of the internal resistance and the isolation resistance of the output terminal, so that it disappears spontaneously. Therefore, even when fuel gas is released or leaked at the inside of the torch head, the risk of combustion or explosion can be avoided without risk

  On the contrary, the classical assembly in which the

  be (29) is absent implies a risk of combustion or explosion, as already mentioned, since sparks are formed between the flat electrode (28) (i.e. terminal (8)) and a

  part a, b, c, d or similar, identified by a cross (x).

  The spring (30) provides the electrical connection between the inner tube (31) and the flat electrode (28) when the nozzle (1)

  is attached to the torch head (6).

  It is also useful to modify the present embodiment as follows: (i) to apply an insulating coating on certain parts such as a, b, c and d, identified by a (x), which can form an electrode sparkle c 8 tee blowtorch, instead of using

the insulating tube (29).

  (ii) ensuring that the spring (30) remains on the

  c 8 torch when removing the nozzle (1).

  (iii) using a "male" blade (38) and a female blade

  "(39), as shown in Fig 8 or 9, instead of the spring (30), so that one of them serve as an input terminal (5) and

  the other power supply terminal (8).

  In each of FIGS. 8 and 9, an insulating tube (29) creates the necessary disruptive distance. However, in FIG. 9, the "male" shield (38) can be made in the form of a thin rod in order to be widely spaced apart. surrounding areas, such as for example the marked portions (x) a, b, c and d (Fig 7), which can form a spark electrode, and constitute the necessary disruptive distance in the form of a separation in the space to

the place of the tube (29).

  (iv) The power supply (109) is not limited to just one piezoelectric block; a battery or power supply

  the electricity network is also possible.

  In other words, the present invention has the

following features -

  Referring again to Fig. 6, a cutting oxygen passage channel (40) is provided between the insulating tube (29) and the inner peripheral surface (34) of the torch head (6). , surface that defines the oxygen port

cutting (15).

  The helical spring (30) of conductive metal is screwed into the inner tube (31) and is subsequently attached to the nozzle (1). This coil spring (30) connects the input terminal (5) of the rear end of the inner tube (31) to the flat electrode (28)

  which serves as a power supply terminal (8).

  There is clearance between the rear end of the nozzle (1) and the front end of the insulating tube (29) to form a gas passage (42). The cutting oxygen, which passes into the gas channel (40). ) through the channel (35) located around the striker (19) and through the channel (36) formed in the intermediate support member (21), reaches a channel (41) provided in the inner tube (31) by the intermediate the passage (42) and the existing space in the spring (30) The inner tube (31) is electrically insulated from the outer tube (32) by electro-insulating members (44, 45) and a

  gas mixture passage channel (46) which forms a spacing.

  FIG. 10 shows another embodiment of the invention where the striking direction of a striker (19) on a piezoelectric block (18) coincides with the direction of the axis of the nozzle (1), the block (18) resting on an inner shoulder of the torch head Except for this feature, the embodiment in question has the same construction as the

first form.

  Fig. 11 shows a modification similar to the embodiment of Fig. 10, except that the coil spring (30)

  is attached to the piezoelectric block (18).

  The embodiments of Figs 10 and 11 may also be modified as follows: (i) a percussion or

  mechanical or manual compression instead of oxygen pressure

  gene as the actuation energy of the piezoelectric block (18),

  (ii) a battery or the electrical network may be used

  in place of the piezoelectric block (18), (iii) the torch can be manual or automatic and

  be used for cutting, welding and machining.

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Claims (6)

  1 spark ignition type torch, including   a torch head (6) on which a spark ignition nozzle (1) can be mounted, said head (6) being provided with a piezoelectric block (18) fixed in position and a corresponding striker. (19), characterized in that the anvil (25) for the block   piezoelectric (18) is part of the torch head (6).   Torch according to claim 1, characterized in that the anvil is a cap (25) closing a cavity (9) which   receives the piezoelectric block (18).   Torch according to claim 1, characterized in that   that the nozzle (1) is provided with spark electrodes (2, 3) to the   front end and input terminals (4, 5) at the rear, the torch head (6) being provided with power supply terminals (7, 8) connectable to the input terminals (4, 5). ) by introducing the nozzle (1) into the torch head (6), the disruptive distance   between the power supply electrodes (7, 8) being greater than   than the air gap allowing a discharge when the nozzle (1) is   removed from the torch head (6).   4 torch according to claim 3, characterized in   the disruptive distance is ensured by an electro-   insulating. Torch according to claim 3, characterized in that the disruptive distance is ensured by a separation in space.   Torch according to claim 3, characterized in that   an electro-insulating member (29) defining a pass channel   gas gap (40) between itself and an inner peripheral surface   (34) of the torch head (6) is provided around a coil spring   coldal connector (30) for connecting one of the power supply terminals   the head (8) of the torch head (6) in electroconductive   at the inlet terminal (5) of the nozzle (1) corresponding to this terminal (8), and in that a passage (42) is formed between the insulating member (29) and the nozzle (1). ) or in the insulating member (29) itself to keep the gas channel (40) in communication   with a gas channel (41) provided in the nozzle (1).   Torch according to claim 6, characterized in that   the helical connecting spring (30) is attached to the nozzle (1).   O torch according to claim 7, characterized in that   that the coil spring (30) is attached to an integral tube (31) of the nozzle (1).