EP2037174B1 - Handtool with improved gas combustion - Google Patents

Description

The invention relates to the field of hand tools with gas combustion.

In tools of this type, the combustion of a gas is used to produce flames, which constitute the active element of the tool.

There are many categories of tools of this type. In torches, for example, flames are mainly used to cut or weld. In torches, flames are usually used to heat all kinds of surfaces to work. The documents US-2880793-A and GB-132869-A disclose such torches.

For example, flares are commonly used to heat, and thus glue, the strips used to mark the passages dedicated to pedestrians on the roadway.

These torches are also useful when it comes to retract plastic films by heating them.

Many areas are concerned. By way of example, films of this type are used to wrap pleasure boats when they are stored out of the water, for example for the winter. These films can also be used to wrap and protect civil engineering buildings.

Gas burning hand tools generally include a gas burner as an active or useful part of the tool.

The burner generally comprises an elongated burner body associated on both sides with a gas injection zone and a gas combustion zone.

Some applications of gas combustion tools require high powers, for example of the order of 100 kilowatts; especially when torch type tools are used, but not only.

To increase the usable power of a tool, the size of the body of its burner is usually increased so that a larger quantity of air and gas mixture to be ignited.

The result is heavy and bulky tools, which are tiring to use, especially when they must be held at arm's length. Such tools are also impractical to handle, especially when it comes to reaching cramped work areas, or quite far from the user, who must then work with outstretched arms.

Tools with a titanium burner body have been proposed to overcome the disadvantage of weight. These tools are bulky, and are also very expensive.

The Applicant's objective is to improve the situation.

The invention relates to a burner for a gas-burning hand tool, of the type comprising an elongate burner body, associated on both sides with a gas injection zone and a gas combustion zone, in which the gas injection zone comprises at least one outlet opening protruding flush outside the periphery of the burner body, so that this periphery supports attractively the flow of gas outside the burner body to the combustion zone.

The invention also relates to a gas combustion hand tool equipped with a burner of this type.

The gas flows from the injection zone to the combustion zone along the outer peripheral surface of the burner body. On this path, the gas mixes with the ambient air. The volume of air that can be mixed with the gas is not limited. This results in much smaller dimensions of this burner body, especially since most of the mixture of gas and air no longer circulates through the interior of the burner body. A larger gas flow can be obtained, while maintaining a reasonable size for a burner. The Applicant has thus succeeded in producing tools whose diameter of the burner body is around 30 millimeters, whereas a conventional design would have required, for a comparable power, a diameter of at least 80 millimeters.

• la figure 1 est une vue en perspective d'une lance torche dotée d'un brûleur à gaz selon un premier mode de réalisation de l'invention,
• la figure 2 est une vue en perspective d'une première partie du brûleur de la figure 1,
• la figure 3 est une vue en coupe longitudinale de la partie de brûleur de la figure 2,
• la figure 4 est une vue en perspective d'une seconde partie du brûleur de la figure 1,
• la figure 5 est une vue en coupe longitudinale de la partie de brûleur de la figure 4,
• la figure 6 est une vue en perspective d'un brûleur de gaz selon un second mode de réalisation de l'invention,
• la figure 7 est une vue en perspective d'un brûleur de gaz selon un troisième mode de réalisation de l'invention,
• la figure 8 est une vue en perspective d'une lance torche dotée du brûleur de gaz de la figure 7,
• la figure 9 est une vue en perspective d'un brûleur de gaz selon un quatrième mode de réalisation de l'invention,
• la figure 10 est une vue en coupe longitudinale du brûleur de la figure 9,
• la figure 11 est une vue en perspective d'une première partie du brûleur de la figure 9,
• la figure 12 est une vue en coupe longitudinale de la partie de brûleur de la figure 11,
• la figure 13 est une vue en perspective d'une seconde partie du brûleur de la figure 9,
• la figure 14 est une vue en coupe longitudinale d'un brûleur selon un cinquième mode de réalisation de l'invention,
• la figure 15 est une vue en perspective d'une variante de réalisation d'un injecteur de gaz pour un brûleur selon l'invention, et
• la figure 16 est une vue en coupe longitudinale de l'injecteur de la figure 15.

Other features and advantages of the invention will appear on examining the detailed description below, and the attached drawings in which:

• the figure 1 is a perspective view of a flare gun with a gas burner according to a first embodiment of the invention,
• the figure 2 is a perspective view of a first part of the burner of the figure 1 ,
• the figure 3 is a longitudinal sectional view of the burner portion of the figure 2 ,
• the figure 4 is a perspective view of a second part of the burner of the figure 1 ,
• the figure 5 is a longitudinal sectional view of the burner portion of the figure 4 ,
• the figure 6 is a perspective view of a gas burner according to a second embodiment of the invention,
• the figure 7 is a perspective view of a gas burner according to a third embodiment of the invention,
• the figure 8 is a perspective view of a flare gun with the gas burner of the figure 7 ,
• the figure 9 is a perspective view of a gas burner according to a fourth embodiment of the invention,
• the figure 10 is a longitudinal sectional view of the burner of the figure 9 ,
• the figure 11 is a perspective view of a first part of the burner of the figure 9 ,
• the figure 12 is a longitudinal sectional view of the burner portion of the figure 11 ,
• the figure 13 is a perspective view of a second part of the burner of the figure 9 ,
• the figure 14 is a longitudinal sectional view of a burner according to a fifth embodiment of the invention,
• the figure 15 is a perspective view of an alternative embodiment of a gas injector for a burner according to the invention, and
• the figure 16 is a longitudinal sectional view of the injector of the figure 15 .

The attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.

The figure 1 shows a torch lance 1, as an example of a gas-burning hand tool embodying the invention.

The flare gun 1 essentially comprises a gripping handle 3 and a gas burner 5, connected to each other by a gas circulation tube 7.

The handle 3 can be connected to a source of gas, expanded to the desired operating pressure, by means of a gas connector 9 arranged to receive the end of a flexible hose (not shown) connected to the source gas (not shown).

The handle 3 comprises in particular a handle 11. This handle 11 comprises an upper portion 11a, intended to receive the palm of the hand of a user, and a lower portion 11b, from which projects, downward, a control lever 13, for actuating a gas inlet device (not shown) housed in the handle 3. A device for adjusting the gas flow could also be provided in place of the admission device, or complement of it. The actuating lever 13 is intended to be actuated by the fingers of the user.

The terms "lower" and "upper" refer here to a rest position of the lance 1, as usually maintained by the user, and shown on the figure 1 . The use of these terms does not imply any limitation on the working positions of this spear 1.

The handle 3 is here made in the form of two separate side pieces attached to one another, which facilitates the assembly of the handle 3 and the mounting of the flow control device.

Optionally, the handle 3 further has a gas pressure indicator 15, disposed here on the upper portion 11a of the handle 11.

The handle 3 may also have a guard (not shown) intended to prevent any inadvertent support on the control lever 13.

The gas circulation tube 7 is arranged to withstand high gas pressures, generally between 0 and 7 bar.

The tube 7 here has a fairly large length. The length of the tube 7 may depend on the applications envisaged for the tool. For example, to date, the Applicant plans to market tubes 300 millimeters, 500 millimeters and 700 millimeters in length, so as to cover a wide range of uses. Different lengths may be provided, possibly specific to a particular application.

A large length of the tube 7 allows the user to cover large areas of work with a small clearance of arms or hand, and, in addition, to access remote work areas.

The burner 5 comprises a gas injector 17, disposed here in the vicinity of one of its ends, a main combustion zone 19, disposed at the end of the burner 5 remote from the injector 17, and a burner body 21 elongate, connecting the combustion zone 19 to the injector 17. The combustion zone 19 forms the "useful" or "active" part of the lance 1: the flame resulting from the combustion of the gas is hung in this combustion zone 19.

The circulation of the gas, from the injector 17 to the combustion zone 19, is attractively supported by the burner body 21, outside thereof. The mixing of the gas with the ambient air occurs along the flow on the burner body 21.

The injector 17 is connected in fluid communication with the circulation tube 7.

The gas to be ignited can enter the lance 1 through the connector 9 and circulate inside the tube 7 to reach the injector 17. From there, the gas reaches the combustion zone 19 by mixing with air . The flow rate of the gas could be controlled by the position of the lever 13 with respect to the handle 3.

The injector 17 is arranged so that the gas reaches the combustion zone 19 by circulating on the peripheral surface 25 of the burner body 21. In other words, the burner body 21 is arranged so that a portion of its The peripheral surface 25 extends from or near the injector 17 to the combustion zone 19. While circulating on this peripheral surface 25, the gas mixes with the ambient air so that a mixture air and gas ready to be ignited reaches this combustion zone 19.

The burner body 21 has a first section 27, close to the injector 17, and a second section 29, close to the combustion zone 19, and connected to the first section 27.

In this embodiment, the first section 27 has a general shape of straight cylinder, and the second section 29 has a generally frustoconical shape, the truncated cone being arranged coaxially with the right cylinder.

The dimensions of the right cylinder and the dimensions of the truncated cone are such that they are connected without abrupt change of diameter, so that a surface and continuous gas flow can be obtained from the injector 17 to the combustion zone. 19.

As it flows on the first section 27 and then on the second section 29, the gas sucks in the surrounding air and mixes with it. A mixture of combustion gases and air is thus available at the combustion zone 19.

The burner body 21 has an inflection zone 31, located here at the limit of the first section 27 and the second section 29. This inflection zone 31 is formed in the form of a transition zone between a general shape cylindrical and a generally frustoconical shape. Other achievements, however, are possible.

The inflection zone 31 makes it possible to create a shock wave in the gas flow. This shock wave increases the disturbances in the flow, thus improving the mixing of the gas with the ambient air.

The figure 2 shows an enlargement of the junction of the injector 17 to the circulation tube 7 and the burner body 21.

The injector 17 has a downstream end face 33, close to the first section 27 of the burner body 21, provided with a plurality of gas outlet orifices 35, arranged in the immediate vicinity of the peripheral surface 25 of the body 21. Each of the gas outlet orifices is flush with the peripheral surface 25. Here, this outcropping is made tangentially, but it could, in different embodiments, be done in an inclined manner, for example so as to obtain, at less partially, a flow along a helical path.

The injector 17 has a general shape of straight cylinder and a substantially hexagonal outer profile. The outlet orifices 35 are distributed substantially equally over a circle centered on the longitudinal axis of the injector 17, and of radius chosen, slightly greater than the outside diameter of the cylinder forming the first section 27 of the burner body 21. injector 17 and the first section 27 of the burner body 21 are arranged substantially coaxially with respect to each other. This configuration provides a substantially uniform injection on the periphery of the burner body 21.

The figure 3 shows in detail the injector 17.

The injector 17 has an upstream end face 43, remote from the downstream end face 33, intended to receive the end of the circulation tube 7 remote from the handle 3.

The injector 17 has a circulation duct 45 for the gas, open on the upstream end face 43, and connected in fluid communication with the gas outlet orifices 35. Here, the circulation duct 45 of the injector 17 is connected to each of the outlet ports 35, each time by an injection passage 47. In other words, each of the passages injection 47 is connected to the circulation duct 45 of the injector 17, and terminates on the downstream end face 33 of the injector 17 via an outlet orifice 35. The outlet orifices 35 are arranged in an outcrop of the peripheral surface, externally to it.

Here, the injection passages 47 are in the form of straight bores, of circular section, and are arranged substantially parallel to the axis of the first section 27 of the burner body 21. Thus, the combustion gas can be injected substantially parallel to the peripheral surface 25, so as to lick it, in a direction of flow substantially parallel to the direction of extension of the peripheral surface 25. The section of each of the orifices 35 may be modified to adapt the gas flow rate on the surface 25. The distance of each of these orifices 35 to the peripheral surface 25 may also be a function of the gas flow rate envisaged.

In the mounted state, the circulation tube 7 opens into the circulation duct 45 of the injector 17, so that a circulation of gas is ensured from the circulation tube 7 to the outlet orifices 35.

The injector 17 and the tube 7 are arranged substantially coaxially with respect to each other.

The tube 7 and the injector 17 are connected by screwing: the tube 7 has, in the vicinity of its corresponding end, an external thread 49, intended to be received in a tapping 51 formed in the vicinity of the upstream end face 43 of the injector 17. Here, the thread 51 is formed in the circulation duct 45 of the injector 17, and the thread 49 on the periphery of the tube 7.

The injector 17 is in the form of a single piece, in which the conduit 45 and the injection passages 47 are machined. The injector thus has excellent resistance to high gas pressures.

The circulation duct 45 comprises a first section 45a, opening on the upstream end face 43, and a second section 45b, of larger diameter, into which the injection ducts 47 open.

On the figure 4 , the burner 5 is provided, in the vicinity of the end of the body 21 remote from the injector 17, with a hooking device, or driving, flame 81, for fixing the flame to said end of the body of burner 21, and a flame ignition device 83 for initiating the combustion of gas.

On the figure 5 a plurality of gas bypass channels 85 connect the peripheral surface 25 of the burner body 21 to a hollow space 87 formed in the burner body 21. The hollow space 87 is open on a useful end face 89, or flame attachment zone, of the burner body 21, remote from the injector 17, here in a central zone of this end face 89. Each of these bypass channels 85 is open on the peripheral surface 25, and opens into hollow space 87.

The hollow space 87 comprises an annular groove 91 formed in the burner body 21 and into which each of the bypass channels 85 opens.

In operation, a small portion of the mixture of air and gas flowing on the periphery of the burner body 21 passes through the bypass channels and opens into the annular groove 91. This annular groove 91 is the seat of pilot flames, it is to say flames that participate in the attachment of the flame on the useful end face 89. The pilot flames maintain the combustion of the greater part of the mixture, which reaches the useful end face 89 while circulating from outside the second section 29, and along the peripheral surface 25.

The mixture of air and gas that emerges in the annular groove 91 is moved with a very low flow rate, compared to the flow velocity of the gas at the outlet of the orifices 35 of the injector or the end. In addition, the pilot flames are protected inside the hollow space 87. This contributes to the efficient creation of pilot flames.

The peripheral surface 25 of the burner body 21 has, in the vicinity of the bypass channels 85, here of the useful end face 89, a deflection section 93, annular and curved, having a spoon-shaped profile. By this form, the deflection section 93 of the peripheral surface 25 takes a small amount of the gas / mixture circulating on the surface 25 and directs this amount to the bypass channels 85. Most of the gas / mixture exceeds this section of 93 to reach the useful end face 89, where it is ignited, partly due to the pilot flames. Different shapes may be provided for the deflection section 93, which form an obstacle to the flow of the gas, for example an annular shoulder shape.

The flame attachment device 81 comprises at least the bypass channels 85 and the annular groove 91.

The ignition device 83 comprises an ignition electrode 95 whose active end is housed in an enclosure 97, arranged in the hollow space 87, in the vicinity of the bypass channels 85.

The ignition enclosure 97 is in the form of a space delimited by a protective wall 99, and connected in fluid communication with the hollow space 87, so that a small amount of the gas mixture and air present in the hollow space 87 can enter the ignition enclosure 97. The protective wall 99 has a plurality of secondary conduits 101 connecting the hollow space 87 to the enclosure 97, arranged here transversely to the electrode 95. The protective wall 99 furthermore has a flame opening 103, facing the active end of the electrode 95, open in the vicinity of the active end face 89.

In the hollow space 87, at the outlet of the bypass channels 85, the mixture of air and gas has a very low flow rate. In addition, a very small amount of mixture reaches, through this path, the hollow space 87. Finally, the hollow space 87 is protected from the outside, and in particular from the greater part of the flow of the gas mixture. air. This results in particularly favorable conditions for the ignition of the mixture. The protected configuration of the ignition site of the flame prevents any risk of "blow-molding" of the spark or the flame by the main flow of the gas, which is made, for the most part, from outside. burner. In other words, the ignition device is protected from the main flow of gas, which can be done at high speed, without the risk of blowing the flame. These favorable conditions allow ignition with the help of sparks, so with a low energy input. Easy ignition of the tool, even with high gas flow rates, is thus obtained.

This overcomes a disadvantage frequently encountered in conventional gas combustion tools: these are particularly delicate and difficult to ignite, especially when large gas flow rates are involved.

The hollow space 87 constitutes a zone of ignition and flame control.

The protective wall 99 is made in the form of a protective cap 105, held in the interior space 87 by means of a fixing washer 107. The fixing washer 107 is housed in a fixing groove 109, arranged in the interior space 87. The washer 107 has a central orifice 111, in which the cap 105 is held, by a suitable fit, a bearing against a stop shoulder 112 and a resilient ring 113, housed in an annular groove 114. The washer 107 and the cap 105 are here made in the form of separate parts, but could also be made in one piece, for example to minimize the number of parts of the tool and facilitate assembly.

Here, the burner body is formed of at least two parts: an end piece comprising the bypass passages 85, the bent portion 93, the hollow space 91, screwed onto a main part essentially comprising the first section of the peripheral surface and a frustoconical part of the second.

A mounting sleeve 115 holds the electrode 95 in the cap 105. The mounting sleeve 115 is in the form of a piece of revolution, having a cylindrical surface 117, mounted in a cylindrical orifice 119 of the cap 105.

The sleeve 115 further has a first shoulder 121, intended to bear against an inner end face 123 of the cap 105. The sleeve 115 also provides a thermal insulation function. To this end, the sleeve is made of an electrically insulating material, or dielectric, for example ceramic.

The sleeve 115 also has a second shoulder 125, on which a compression spring 127 is supported. The opposite end of this compression spring 127 rests on the bottom of a longitudinal recess 129 formed inside the body burner 21, here in the second section 29. The spring is further guided by a cylindrical surface 131 provided in the vicinity of the end of the sleeve 115 remote from the active end of the electrode. This central recess 119 here has a stepped structure, or in stages, generally following the frustoconical outer profile of this second section 29.

The electrode 95 is supplied with electric current by a conductor wire 133, connected to a current source not shown, housed here in the handle 3. The lead wire 133 is surrounded by a protective sheath 135. This short conductor wire 133 inside the circulation tube 7, passes through the injector 17, then enters a longitudinal passage 137 passing through the inside of the first section 27 of the burner body 21 ( figure 5 ), along its longitudinal axis, to reach the central recess 129 of the second section 29 of the burner body 21.

The burner body 21 and the injector 17 are screwed one on the other: the downstream end face 33 of the injector 17 has a projection 73 provided with a thread 137 which cooperates with a tapping 141 arranged centrally inside the first section 27 of the burner body 21.

On the figure 6 , the gas burner 143 illustrates a second embodiment of the invention.

The burner 143 comprises an injector 145, similar to the injector 17, and a burner body 147. This burner body 147 comprises a first section 149, in the general shape of a right cylinder, and a second section 151, of general appearance. truncated. This second section 151 externally has a stepped shape, that is to say that the outer peripheral surface 153 of the burner body 147 describes, along the second section 151, successive bearings 154 in the form of coaxial cylindrical portions, of which the diameter increases with the distance to the first section 149.

The successive stages 154 make it possible to control the disturbance of the gas flow so that the flame clings correctly on an active end face 144 of the burner 143, in the vicinity of a combustion zone 155. This staged configuration offers a length total burner 143 and a maximum cone width of the second section 151 smaller than the burner 5 previously described. In other words, the burner 143 has a small footprint, thanks to the stepped configuration of the second section 151.

The burner 143 further comprises a flame attachment device 156 and an ignition device 157 similar to those previously described.

On the figure 7 the gas burner 158 illustrates a third embodiment of the invention.

The burner 158 comprises a gas injector 159, similar to the injector 17 previously described, and a burner body 161 connecting the injector 159 to a combustion zone 163, or active zone.

The burner body 161 comprises a first section 165, close to the injector 159, and a second section 167, connected to the first section 165 and close to the combustion zone 163, this combustion zone 163 being disposed in the vicinity of an active end face 164 of the burner 161 remote from the injector 159.

The first section 165 has a general shape of straight cylinder, while the second section 167 has a general frustoconical shape. The burner body 161 has a general shape of revolution and elongated.

The burner 158 further comprises two protective fins 169 protruding from the burner body 161 radially.

The fins 169 are oppositely disposed with respect to the axis of the burner body 161, thereby protecting half of a plurality of gas injection orifices 171, in the direction of the outside air currents.

Each of the fins 169 has, in an area remote from the burner body 161, a support foot 173, formed here in the form of a generally flat piece and disposed transversely to the fin 169.

A foot 173 makes it possible to place the burner 157 on the ground, or on any other flat surface, when the torch 1 is not used, as shown in FIG. figure 8 .

Here, each of the fins 169 is made in the form of two plane plates 175 contiguous to each other, each having a general delta shape, a corner of this delta being bent substantially at right angles to form a part of the foot. 173.

The burner body 161 is made in the form of two pieces placed one against the other, each of these parts comprising two half-fins 175, a half-cylinder forming the first section 165, and a half-cone forming the second section 167. These parts can be made by stamping, then welded or clinched. Such a configuration of the burner makes it possible to house at least some of the elements constituting a flame catching device 177 and an ignition device 178 before fixing the two pieces together. Where appropriate, beads may be provided inside these parts to facilitate the positioning of said elements.

The flame attachment device 177 and the ignition device 178 are here analogous to those previously described. These devices are attached to the end of the burner body 161.

On the figures 9 and 10 a gas burner 179 illustrates a fourth embodiment of the invention.

The burner 179 comprises a gas injector 181, disposed at one end of a burner body 183, which has at its other end a combustion zone 185.

The burner body 183 comprises a first section 187, close to the injector 181, and a second section 189, close to the combustion zone 185.

The first section 187 has a general shape of straight cylinder, while the second section 189 has a generally frustoconical shape.

The Figures 11 and 12 illustrate in detail the injector 181.

The injector 181 comprises a connecting sleeve 191 with an upstream end face 193, arranged to receive the end of the circulation tube 7 remote from the handle 3, a downstream end face 195, close to the body of the burner 183, and a gas flow conduit 197 connecting the upstream end face 193 and the downstream end face 195.

The duct 197 of the sleeve 191 comprises an inlet section 199, opening on the upstream end face 193, and arranged to receive the end of the tube 7.

Here, the inlet section 199 has a tapping 201 arranged to cooperate with a thread (not shown) provided at the end of this tube 7.

The conduit 197 of the sleeve 191 further comprises an outlet section 203, opening on the downstream end face 197, and connected in fluid communication with the inlet section 199.

The injector 181 further comprises an inner core 205 having an upstream end face 207 and a downstream end face 209.

The core 205 is arranged to be housed, at least partially, in the outlet section 203 of the sleeve 191. In particular, the core 205 has a general external appearance homologous to the general appearance of the outlet section 203, but of dimensions, in section, homothetic, so that the outlet section 203 is not closed by the core 205. In other words, the periphery of the core 205 follows the periphery of the outlet section of the conduit 197.

In the vicinity of the downstream end face 195 of the sleeve 191, the core 205 has partitioning elements 213, protruding from the periphery of the core 205 and in contact with the periphery of the outlet section 203. The injector thus has a plurality of gas outlet openings 211, in the form of lights arranged in the vicinity of the end face. downstream 195 of the sleeve 191, between the inside of the sleeve 191 and the outside of the core 205, these slots being separated from each other by the partitioning elements 213. In other words, the gas outlet ports 213 are here under in the form of annular portions disposed in close proximity to the peripheral surface of the burner body. The partitioning elements 213 have an annular portion shape.

The gas outlet orifices 203 are flush with the periphery of the first section 187

More specifically, the outlet section 203 of the duct 197 has a first section 215, close to the cylindrical inlet section 199, which extends towards the downstream end face 195 into a second trunk section 217. cone divergent, itself extending into a third section 219, cylindrical, which ends in a fourth section 221, cylindrical and larger diameter than the third section 219.

The periphery of the core 205 has a cylindrical first section 223 extending towards the downstream end face 195 into a second diverging frustoconical section 225, itself extending into a third, cylindrical and larger diameter section 227, which ends with a fourth section 229, also cylindrical and of larger diameter. The fourth section 229 carries the partition elements 211, which project from this section, radially. In the mounted state, the periphery of the core 205 is slightly offset in the axial direction relative to the periphery of the outlet section 203, towards the downstream end face 195. In other words, the first section 223 of the core 205 begins a little further from the upstream end face 193 of the sleeve 191, and extends a little further than the peer section of the output section 223, and so on for the other sections.

The core 205 is here produced in the form of a monobloc piece, of revolution, and hollow. A through hole 231 opening on the upstream end face 193 of the core 205 is arranged to pass a conductive wire 233 surrounded by a protective sheath 235 to electrically power a flame ignition device 236 (visible on the figure 9 ), similar to that previously described. An annular seal 237 is placed between the through hole 231 and the protective sheath 235.

The core 205 is arranged, in the vicinity of its downstream end face 195, in a cylindrical surface 239 intended to receive the end of the first section 187 of the burner body 183, formed here in the form of a tubular piece.

The burner body 183 has a peripheral surface 240, formed in part by the outer surface of the tubular piece forming the first section 187. In the assembled state, said tubular piece is flush with the section 229 of the outer surface of the core 205. As a result, the gas outlet ports 211 are flush with the peripheral surface 240 of the burner body 183.

The figures 10 and 13 show in detail the combustion zone 185.

The burner body 183 has an active end face 241, remote from the injector 181. The combustion zone 185 comprises a hollow space 243, formed in the burner body 183 and open on the active end face 241. A plurality of branch conduits 245 connect the peripheral surface 240 of the burner body 183 to the hollow space 243, so that at least a small portion of the gas propelled by the injector 181 and circulating on peripheral surface 240 is found in hollow space 243. Most of the mixture of air and gas flows through the outside of burner body 183 to reach the active end face 241 Each of the bypass ducts 245 extends first parallel to the longitudinal axis of the first cylindrical section 187 and then deflects to reach the hollow space 243.

The bypass ducts 245 are thus formed at the same level of the peripheral surface 240, in the extension thereof, so that a small amount of the mixture of air and gas enters directly.

The bypass ducts 245 are created by providing free spaces, in the vicinity of the end of the first section 187, between the peripheral surface 240 and an envelope surface 247 surrounding this end of the first section 187. Here, the surface 247 has a cylindrical shape, of diameter substantially larger than the diameter of the first section 187.

In this configuration, the proportion of air and gas mixture taken from the main flow on the peripheral surface 240 depends largely on the height of the bypass pipes 245, which can therefore be adapted according to the ignition.

In the vicinity of the end of the first section 187, partitioning elements 249 are housed in the space left free between the peripheral surface 240 and the envelope surface 247, so as to delimit the ducts. 245. The partition elements 249 protrude radially from the envelope surface 247 and come into contact with the peripheral surface 240.

Here, an end piece 251 is attached to the vicinity of the end of the first section 187. In other words, the burner body 183 here comprises at least two distinct parts, which are attached to one another.

The end piece 251 has a peripheral surface 253, which forms the peripheral surface 240 of the second section 189 of the burner body 183. This peripheral surface 253 has a generally frustoconical shape.

The end piece 251 comprises a holding portion 255, annular and disposed on the central axis of this end piece 251. The holding portion 255 is open on the hollow space 243, and is arranged to receive a holding sleeve 257 An ignition electrode 259 is axially housed in the holding sleeve 257. This electrode 259 is connected to the lead wire 233.

A plurality of junction ports 261 are formed in the end piece 241, so as to connect the bypass ducts 245 to the hollow space 243. Each of the junction ports 261 extends substantially parallel to the longitudinal axis In operation, the end of these junction ports 261 located in the hollow space 243 are the seat of pilot flames. These ends are arranged around the ignition device 236, which is located in a central zone of the hollow space. Here, these ends of the junction ports 261 are distributed substantially evenly over a circle centered on the ignition device 236. The junction ports 261 form part of at least one flame attachment device 262.

The pilot flames are created in a favorable place, where the flow velocity of the gas at the outlet of the orifices 261 is small: this improves the ignition possibilities of the gas. These pilot flames light the main flow of the mixture of air and gas, flowing from the outside, whose flow rate, greater, would not otherwise allow the attachment of the flame on the active end face 241 .

The peripheral surface 253 of the end piece 251 comprises a first section 263, close to the first section 187 of the frustoconical burner body 183, opening towards the active end face 241. The peripheral surface 253 of the part end 251 ends in a second frustoconical section 265, closing towards the active end face 241. This second section 265 of the end piece 251 ends practically on the hollow space 243. A joining section 267, annular, transverse to the longitudinal axis of the burner body 183 connects the first 263 and second 265 sections of the end piece 251.

On the figure 14 , the burner 269 illustrates a fifth embodiment of the invention.

The burner 269 comprises a gas injector 271 similar to the injector 181 previously described, a burner body 273, connecting the injector 271 to an active end face 275 located in a combustion zone 276.

The burner body 273 comprises a peripheral surface 274 having a first generally cylindrical section 277 and a second generally frustoconical section 279 opening towards the active end face 275.

The burner body here comprises a main piece 281, tubular, on which is fitted an end piece 283, at its end remote from the injector 271. The first section 277 of the peripheral surface 274 is formed by a peripheral surface portion of the main piece 281, while the second section 279 is formed by a portion of the peripheral surface of the end piece 283. The burner body comprises a hollow space 285 open on the active end face 275. The hollow space 285 has a cylindrical shape, and is disposed along the longitudinal axis of the burner body 269.

The fitting of the end piece 283 on the main piece 281 is performed here without sparing any game other than the clearance required for assembly. The gas flowing on the peripheral surface 270 can not reach the hollow space 285 other than by taking the periphery of the second section 279.

A connecting duct 287 formed in the end piece 283 connects the hollow space 285 to the internal space 289 of the main piece 281, which is tubular here.

A plurality of exhaust ports 291 connects the first section 270 to the interior space 289 of the main part 281. The exhaust ports 291 are distributed around the circumference of the first portion 270, substantially closer to the injector 271 only the active end face 275.

An ignition device 293, similar to that of the previous embodiment, is housed in a holding plug 295 closing a downstream end face 297 of the core 297 of the injector 271. The active end of the electrode 26 ignition 299 being disposed in the interior space 289 of the main room.

The exhaust ports 291 are arranged in the vicinity of the ignition device 293.

In the interior space 289 circulates a quantity of mixture of combustion gas and unburned air.

The ignition system is protected from the outside environment.

The attachment of the flames on the active end face 275 is achieved by the disturbances, or turbulence, which are created at the end of the second frustoconical section 279.

On the Figures 15 and 16 , a gas injector 300 is shown as an alternative embodiment of the previously described injectors.

The injector 300 consists mainly of a female part 301 and a male part 303, housed in the female part 301.

The female part 301 comprises a receiving space 305, into which a gas inlet conduit 307 opens. The receiving space 305 comprises, at its opening on the outside, a chamfered edge 309 disposed opposite a substantially frustoconical portion 311 of an outer surface 313 of the male portion 303.

The male part 303 has a cylindrical fixing section 315, provided with a thread 317 adapted to cooperate with a tapping 319 provided in the female part 301.

The angle of the chamfered edge 309 is substantially equal to the apex angle of the frustoconical portion 311, so that an annular gas outlet port 321 is thus obtained.

The burners described above allow the use of high gas flow rates, corresponding to significant useful working power, without the disadvantage of a large footprint. This advantage is largely related to the circulation of the combustion gas supported by the outer periphery of these burners. When the circulation of the gas is inside a burner body, as is the case in conventional burners, the increase of the gas flow, and consequently also the amount of air to mixing, leads to the increase of the internal section of the burner body. Here, even in the presence of large gas flows, the gas mixes adequately with the surrounding air, so that the mixture can easily be ignited. Circulation and mixing of the gas is done on the outside of the burner, it is possible to obtain tools with a small footprint.

The outer surface, or, more generally, the length of the gas path outside the burner, can be increased or decreased, depending on the desired characteristics for the mixture of air and gas, and possibly the attachment of flame.

The burners described provide particularly efficient ignition and flame control, particularly with respect to conventional burners. This advantage results in part from the situation of the ignition and control devices inside the burner body, in an area where the flow of gas is disturbed, and at the same time protected from the main flow which tends to extinguish, or blow, the flames.

Indeed, the gas velocity at the injector outlet can be very high, but this speed is considerably reduced or very low when the gas enters the enclosure protected. This is due, in particular to the disturbances of the flow in this zone.

This arrangement of the ignition and the control inside the burner body is allowed by the external circulation of the gas: it is because the greater part of the mixture of air and gas reaches the active end of the gas. the tool from outside of it that sufficient space is released inside the burner.

The invention is not limited to the burners of the previously described embodiments.

The burners described have peripheries of revolution. However, surfaces of all shapes, for example flat, are suitable for the implementation of the invention. An important feature is that the gas injection takes place flush with the peripheral surface, so that adequate, surface-flow, high flow gas flow can be obtained.

The described injectors have gas outlet orifices of circular section, or partially annular, or a single annular orifice. Other configurations may be envisaged, in particular the presence of a single outlet orifice. The orifices can be made according to different techniques, by milling, broaching, or drilling.

Second peripheral surface sections of the frustoconical burner body have been described. This shape makes it possible both to house the ignition and flame control devices internally and to obtain an active surface adapted to the desired use of the tool. However, different geometries can be envisaged, for example in depending on the use or the shape of the desired flame, or the gas flow.

Whenever the periphery of the burner body has a sectional change from a cylindrical shape to a frusto-conical shape, an inflection zone is created, which improves the mixing between the flue gas and the surrounding air, by generation of a shock wave.

In the burners described, most of the gas and air mixture flows to the combustion zone from outside the tool exclusively. In very specific conditions, it could however be expected that a portion of this flow is in an internal portion of the tool, especially when it does not affect the overall size of the tool or the flow involved .

As described, the burners have a slow extinguishing, in the sense that a release of the gas control lever results in a complete extinction of the flames delayed by a few seconds (for example, 5 seconds). This allows the tool to be re-ignited by simply operating the lever, without having to actuate the flame ignition device. This makes the tool more tolerant to untimely release of the lever. However, when rapid extinguishing is desired, for example for safety reasons, a stop device may be provided to stop suddenly the flow of gas inside the tool, concomitantly with the release of the lever of ordered.

The burner according to the invention is not limited to its use in the torch 1 described here by way of example only, but applies to all types of hand tools gas combustion.

Claims (27)

1. Burner (5, 143, 158, 179, 269) for a gas burning hand tool (1), of the type comprising an elongated burner body (21, 147, 161, 183, 273), associated at opposite ends of the burner body with a gas injection zone (17, 145, 159, 181, 271) and a gas combustion zone (19, 155, 163, 185, 276), characterised in that the gas injection zone (17, 145, 159, 181, 271) comprises at least one outlet orifice (35, 171, 211, 309) terminating flush with the outside of the periphery (25, 153, 240, 270) of the burner body (21, 147, 161, 183, 273), so that this periphery (25, 153, 240, 270) attractively supports the circulation of the gas on the outside of the burner body (21, 147, 161, 183, 273) towards the combustion zone (19, 155, 163, 185, 276).
2. Burner according to claim 1, wherein said periphery (25, 153, 240, 270) comprises an at least partially cylindrical first longitudinal section (27, 149, 165, 187, 277) close to the injection zone (17, 145, 159, 181, 271).
3. Burner according to one of claims 1 and 2, wherein said periphery (25, 153, 240, 270) comprises an at least partially truncated conical second longitudinal section (29, 151, 167, 189, 279) close to the combustion zone (19, 155, 163, 185, 276).
4. Burner according to claim 3, wherein the second section (151) has a stepped structure.
5. Burner according to one of the preceding claims wherein the gas injection zone (17, 145, 159, 181, 271) has a plurality of outlet orifices (35, 171, 211), each of the outlet orifices (35, 171, 211) terminating flush on the outside of the periphery (25, 153, 240, 270) of the burner body (21, 147, 161, 183, 273).
6. Burner according to one of the preceding claims, wherein the outlet orifice (35, 171, 211, 309) terminates in a gas injection channel (45; 47, 197), said channel (35, 171, 211, 309) extending parallel to the external periphery (25, 153, 240, 270) of the burner body (21, 147, 161, 183, 273) at least in the vicinity of said orifice (35, 171, 211, 309).
7. Burner according to one of the preceding claims, wherein the injection zone (17, 145, 159, 181, 271) has a plurality of outlet orifices (35, 171, 211) distributed around the peripheral surface.
8. Burner according to one of the preceding claims, wherein the injection zone (181) comprises at least one at least partly annular outlet orifice (211, 309), surrounding at least partly the periphery (183) of the burner body (183).
9. Burner according to one of the preceding claims, wherein the gas combustion zone (19, 155, 163, 185, 276) has a flame capture zone (89, 144, 161, 241, 275) situated in the vicinity of the end of the burner.
10. Burner according to claim 9, wherein the periphery (25, 153, 240, 270) of the burner body (21, 147, 161, 183, 273) attractively supports a main gas circulation on the outside of the burner body (21, 147, 161, 183, 273) as far as the flame capture zone.
11. Burner according to one of claims 9 and 10, wherein the combustion zone (19, 155, 163, 185, 276) further has a flame control device (81, 156, 177, 262) disposed in an internal zone (87, 243) of the burner body (21, 147, 161, 183, 273), open at the flame capture zone (89, 144, 161, 241, 275).
12. Burner according to claim 1, comprising at least one branch passage (85, 245) arranged so as to guide a secondary gas circulation from outside the periphery (25, 153, 240) of the burner body (21, 147, 161, 183) to said internal zone (87, 91, 243) of the burner body (21, 147, 161, 183), in the proximity of the flame control device (81, 156, 177, 262).
13. Burner according to claim 12, wherein the flame capture device (81, 156, 177, 262) comprises at least one gas flow orifice (85, 261) in fluid communication with the branch passage (85, 245), said flow orifice being arranged in the proximity of the flame capture zone (89, 144, 161, 241).
14. Burner according to claim 13, comprising a plurality of gas flow orifices (85, 261), distributed in a manner corresponding to the opening of the internal zone (87, 91, 243) on the flame capture zone (89, 144, 161, 241).
15. Burner according to one of claims 9 to 14, wherein the flame capture zone (89, 144, 161, 241, 275) comprises an end face of the burner body (21, 147, 161, 183, 273).
16. Burner according to one of the preceding claims, further comprising a flame lighting device (83, 157, 178, 236, 293) disposed in an internal zone (87, 91, 243) of the burner body (21, 147, 161, 183, 273).
17. Burner according to claim 16, wherein the flame lighting device (83, 157, 178, 236, 293) comprises a protected site (243) in the internal space (87, 91, 243), in fluid communication with the internal space (87, 91, 243).
18. Burner according to one of claims 16 and 17 in combination with claim 9, wherein the internal zone (87, 91, 243) accommodating the flame lighting device (83, 157, 178, 236, 293) is open on the flame capture zone (89, 144, 161, 241, 275).
19. Burner according to claim 18, comprising at least one branch passage (85, 245) for guiding a secondary circulation of gas from the periphery (25, 240) of the burner body (21, 183) to the internal zone (87, 243) of the burner body (21, 183), in the vicinity of the flame lighting device (83, 236).
20. Burner according to one of the preceding claims and dependent on one of claims 12 and 19, wherein the periphery (25) of the burner body (21) has in the vicinity of the branch passage (85) a deviation portion (93) designed so as to remove a part of the peripheral gas flow and guide this part of the flow towards the branch passage (85).
21. Burner according to claim 20, wherein the deviation portion (93) has an annular shape.
22. Burner according to one of claims 17 and 18 in combination with claim 9, wherein the flame lighting device (293) is remote from the flame capture zone (275), and wherein a circulation channel (289) for combustion gas connects the flame capture zone (275) in the vicinity of the flame lighting device (293).
23. Burner according to one of the preceding claims, wherein the periphery (25) of the burner body (21) has a zone of inflection (31), between the injection zone (17) and the combustion zone (19).
24. Burner according to claim 23 dependent on one of claims 12 and 19, wherein the branch passage (245) extends a first section (187) of the burner body (183), and is open in the vicinity of the zone of inflection (31).
25. Burner according to one of the preceding claims, having at least one protective flange (169) projecting outside the periphery of the burner body (161), and extending from the injection zone (159) to the vicinity of the combustion zone (163).
26. Gas burning hand tool comprising a burner according to one of the preceding claims.
27. Hand tool according to claim 26, further comprising a gripping handle (3) carrying a gas control lever (13), and a gas transporting tube (7) connecting the gripping handle (3) to the burner.

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