Fire extinguisher lance and fire extinguisher comprising such a lance

Abstract

Lance for fire extinguisher and fire extinguisher comprising such a lance A lance (18) for fire extinguisher is intended for the projection and foaming of a fluorine-free extinguishing agent. The lance defines a flow duct (22) and comprises, in the direction of flow: - an injection nozzle (28) comprising at least two injection holes, - at least one air inlet opening (30) connecting the outside of the lance to the flow duct, intended to suck air from the outside of the lance towards the inside of the flow duct, so as to allow the foaming of the extinguishing agent by mixing with the air, - a foaming screen (34), intended to improve the foaming of the extinguishing agent, - a downstream spark gap (36), intended to divide the flow of the extinguishing agent into several separate jets.To improve the foaming of the extinguishing agent, the downstream spark gap comprises at least three branches and the lance further comprises an upstream spark gap (32), located between the air inlet opening and the foaming screen. Figure for abstract: 4.

Description

Title of the invention: Lance for fire extinguisher and fire extinguisher comprising such a lance

[0001] The present invention relates to a fire extinguisher lance and a fire extinguisher comprising such a lance.

[0002] In the field of fire extinguishers, it is known to use fire extinguishers projecting an extinguishing agent composed of a mixture of water and surfactant additive, which is foamed during its projection, in order to extinguish class A and class B fires, these fire classes being defined by the NF EN 2 standard. Such a fire extinguisher generally comprises a fire extinguisher body, a flexible hose and a lance. The passage of the extinguishing agent in the lance causes it to foam. The performance of the extinguishers is linked to the suitability of the extinguishing agent with the lance, each extinguishing agent having a variable foaming capacity depending on the lance used.

[0003] The surfactant additive used in the extinguishing agent usually comprises fluorine, which gives the extinguishing agent good foaming properties. Since such an extinguishing agent is easy to foam, the design of the associated lances is relatively simple and the extinguishers thus obtained can be used indifferently on class A and class B fires. These extinguishers are generally satisfactory, but lead to environmental pollution linked to the use of fluorine.

[0004] It is also known to use an extinguishing agent whose surfactant additive does not include fluorine. However, the use of such a fluorine-free extinguishing agent with known lances is not satisfactory, because the known lances do not allow effective foaming of the extinguishing agent. The performance of the extinguishers is therefore reduced when they use a fluorine-free extinguishing agent.

[0005] To compensate for this drop in performance, BE-A-1028003, which describes the use of a fluorine-free extinguishing agent, proposes two different lances, intended respectively to extinguish class A fires and class B fires. Each lance is specifically adapted to improve the foaming of the extinguishing agent depending on the class of fire to be extinguished. Thus, the performance of extinguishers using these lances is reduced, since they cannot be used indifferently against class A and class B fires.

[0006] There is therefore a need for a high-performance fire extinguisher using a fluorine-free extinguishing agent and suitable for extinguishing class A and class B fires.

[0007] It is this need that the invention more particularly intends to address by proposing a new, more efficient fire extinguisher lance when a fluorine-free agent is used. used.

[0008] To this end, the invention relates to a fire extinguisher lance intended for the projection and foaming of a fluorine-free fire extinguishing agent, the lance defining a flow conduit for the fire extinguishing agent extending along a main axis, the lance comprising, in the direction of flow of the fire extinguishing agent along the main axis:

[0009] - an injection nozzle comprising at least two injection holes;

[0010] - at least one air inlet opening connecting the exterior of the lance to the conduit flow, the air inlet opening being intended to draw air from the outside of the lance into the inside of the flow conduit, so as to allow the foaming of the extinguishing agent by mixing with the air;

[0011] - a foaming screen, intended to improve the foaming of the extinguishing agent; and

[0012] - a downstream spark gap, intended to divide the flow of the extinguishing agent into several distinct jets.

[0013] According to the invention, the downstream spark gap comprises at least three branches, and the lance further comprises an upstream spark gap, located between the air inlet opening and the foaming screen.

[0014] Thanks to the invention, the presence of two spark gaps, arranged on either side of the foaming screen, allows efficient foaming of the extinguishing agent, without causing significant pressure losses or reflux of the extinguishing agent through the air inlet openings. In addition, the three branches of the downstream spark gap make it possible to obtain a jet of foamed extinguishing agent whose characteristics, such as for example the shape and density of the foam, are suitable for extinguishing class A and B fires.

[0015] According to advantageous, but not obligatory, aspects of the invention, the fire extinguisher lance incorporates one or more of the following characteristics, taken in isolation or in any technically admissible combination:

[0016] - The upstream spark gap and the downstream spark gap comprise the same number of branches and the branches of the downstream spark gap are angularly offset from the branches of the upstream spark gap, around the main axis.

[0017] - The injection holes of the injection nozzle are angularly offset, around the main axis, branches of the upstream spark gap and branches of the downstream spark gap.

[0018] - The sum of the section of the injection holes is between 5.5 mm2 and 10 mm2, preferably equal to 8 mm2, the section of each injection hole being measured perpendicular to the main axis, and, preferably, the injection nozzle comprises six injection holes.

[0019] - The injection nozzle comprises, upstream of the injection holes, a restriction ex inner, which converges towards the main axis in the direction of flow of the extinguishing agent and which forms a narrowing of the flow duct, and an internal restriction inner, arranged in the center of the flow duct, which diverges from the main axis in the direction of flow of the extinguishing agent and which forms a narrowing of the flow duct. The outer restriction and the inner restriction are configured to accelerate the flow of the extinguishing agent and to converge the flow of the extinguishing agent towards the injection holes and, preferably, the outer restriction has a truncated cone shape and the inner restriction is a cone.

[0020] - Each branch of the downstream spark gap has a tip-shaped section, one of which tip is directed upstream of the flow conduit. Preferably, the tip-shaped section of each branch of the downstream spark gap is an isosceles triangle-shaped section. Preferably, an angle of a main vertex of the tip-shaped section is between 10° and 60°, more preferably equal to 25°.

[0021] - A length, measured along the main axis, between a downstream end of the spark gap downstream and a downstream end of the lance is between 1 mm and 10 mm, preferably equal to 5 mm.

[0022] - A length between the upstream spark gap and the foaming screen is greater than or equal to four times a length between the frothing screen and a downstream end of the downstream spark gap, the lengths being measured along the main axis.

[0023] - From the injection nozzle to the upstream spark gap, the flow conduit has a truncated cone-shaped which converges in the direction of flow of the extinguishing agent, and, from the upstream spark gap to the foaming screen, the flow duct has a truncated cone-shaped which diverges in the direction of flow of the extinguishing agent.

[0024] According to another aspect, the invention also relates to a fire extinguisher comprising a fire extinguisher body, a flexible hose and a lance, the fire extinguisher body comprising a bottle of extinguishing agent. According to the invention, the lance is as mentioned above. In addition, the extinguisher comprises a filter located upstream of the injection nozzle and intended to filter any impurities present in the extinguishing agent, this filter being arranged in the lance or upstream thereof.

[0025] This extinguisher induces the same advantages as those mentioned above concerning the lance of the invention.

[0026] The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a fire extinguisher lance and of a fire extinguisher given solely by way of example and with reference to the appended drawings in which:

[0027] [Fig.l] [Fig.l] is a perspective view of a fire extinguisher according to the invention;

[0028] [Fig.2] [Fig.2] is a perspective view of a lance belonging to the fire extinguisher of [Fig.l], the lance being in accordance with the invention;

[0029] [Fig.3] [Fig.3] is an exploded perspective view of the lance of [Fig.2];

[0030] [Fig.4] [Fig.4] is a longitudinal section of the lance of Figures 2 and 3, according to the plan IV of [Fig.2];

[0031] [Fig.5] [Fig.5] is a cross-section of the lance of Figures 2 to 4, according to the plan V of [Fig.4];

[0032] [Fig.6] [Fig.6] is a view from downstream of the lance of Figures 2 to 5, in the direction of the arrow F6 in [Fig.2];

[0033] [Fig.7] [Fig.7] is a longitudinal section of a nozzle belonging to the lance of the figures 2 to 6, according to plan VII of [Fig.3]; and

[0034] [Fig.8] [Fig.8] is a section similar to [Fig.4], on which the flow of a extinguishing agent through the nozzle is shown.

[0035] A fire extinguisher 10 is shown in [Fig.l]. The extinguisher 10 is a portable fire extinguisher of the water spray extinguisher type with additive, or of the foam extinguisher type. The extinguisher 10 is intended to extinguish class A fires, i.e. dry type fires, in other words fires of solid materials whose combustion forms embers, such as for example wood, and class B fires, i.e. fat type fires, in other words fires involving liquids and liquefiable solids, such as for example hydrocarbons or greases.

[0036] To extinguish class A and B fires, the extinguisher 10 uses an extinguishing agent, in liquid form, composed of a mixture of water and surfactant additive, which is sprayed using a propellant.

[0037] The fire extinguisher 10 comprises a fire extinguisher body 12, a flexible hose 14, a socket 15 equipped with a trigger 16 and a lance 18. The socket 15 is intended to be held by a user to direct the lance 18 towards the base of the flames and to actuate the trigger.

[0038] In a manner known per se, the extinguisher body 12 forms a reservoir which is filled with water and which further comprises a bottle of surfactant additive, which in the example is a fluorine-free surfactant additive. In the example, the extinguishing agent formed from the mixture of water and the surfactant additive is therefore a fluorine-free extinguishing agent.

[0039] Preferably, the tank of the extinguisher body 12 is designed to accommodate 6 liters (L) of extinguishing agent, or 9L of extinguishing agent. When the tank is designed to accommodate 6L of extinguishing agent, this extinguishing agent is for example composed of approximately 5.9L of water and approximately 0.1L of fluorine-free surfactant additive.

[0040] The extinguisher 10 also comprises a handle 20, provided so that its actuation causes the surfactant additive to mix with the water, thus forming an extinguishing agent, and the propulsion of the extinguishing agent, in liquid form, from the extinguisher body 12 towards the lance 18 via the flexible hose 14.

[0041] Alternatively, the extinguisher body does not include a bottle of surfactant additive, and the surfactant additive is then mixed with the water filling the tank at the time of manufacture of the extinguisher 10.

[0042] In a manner known per se, the extinguisher body 12 may be “permanently pressurized”, that is to say that the water filling the tank is constantly under pressure, or the extinguisher body comprises a propellant cartridge, such as for example CO2, the release of which into the extinguisher body causes the pressure of the tank to rise. When the extinguisher body 12 comprises a propellant cartridge, then actuation of the handle 20 causes the propellant cartridge to be struck.

[0043] The trigger 16, mounted on the socket 15 between the flexible pipe 14 and the lance 18, makes it possible to authorize or interrupt the flow of the extinguishing agent through the lance 18. Upon reaching the lance 18, the extinguishing agent is in liquid form, and its passage through the lance 18 causes it to foam, thus improving its fire extinguishing properties.

[0044] Thus, at the outlet of the lance 18, the extinguishing agent is in the form of a foam, making it possible to effectively extinguish class A and B fires.

[0045] As best seen in Figures 2 to 4, the lance 18 defines a flow conduit 22 for the extinguishing agent. The lance 18 extends along a main axis X. In the remainder of the description, the terms “upstream” and “downstream” are understood relative to the main axis X and refer to the direction of flow of the extinguishing agent inside the flow conduit 22. 18A denotes the upstream end of the lance 18 and 18B the downstream end of the lance.

[0046] In the direction of flow of the extinguishing agent, that is to say from its upstream end 18A to its downstream end 18B, the lance 18 comprises the following elements:

[0047] - a connecting thread 24; - a 26 filter; - an injection nozzle 28; - one or more air inlet openings 30 connecting the exterior of the lance 18 to the interior of the flow duct 22, in the example four air inlet openings; - an upstream spark gap 32; - a foaming sieve 34; and - a downstream spark gap 36.

[0048] The filter 26, the upstream spark gap 32, the foaming screen 34 and the downstream spark gap 36 are each arranged in a plane perpendicular to the main axis X.

[0049] The connecting thread 24 allows the connection of the lance 18 to the socket 15 by screwing. Thus, the socket 15 and the lance 18 are rigidly assembled, so that a user of the fire extinguisher 10 can direct the lance 18 towards a fire by manipulating the socket 15.

[0050] In practice, the connecting thread 24 is arranged, along the main axis X, at level of an intake zone ZI of the flow duct 22.

[0051] The filter 26 is intended to filter any impurities present in the extinguishing agent coming from the extinguisher body 12. The filter 26 is, in the example, a grid with meshes of 1 mm by 1 mm.

[0052] As best seen in [Fig. 5], the injection nozzle 28 has several injection holes 38, in the example six injection holes 38. Advantageously, the sum of the section of the injection holes 38 is between 5.5 mm2 and 10 mm2, preferably equal to 8 mm2, the section of each injection hole being measured perpendicular to the main axis X. In the example, the diameter of each injection hole 38 is equal to 1.3 mm. The center of each injection hole 38 is located at a distance from the main axis X, for example 4.3 mm from the main axis Z. In addition, the injection holes are preferably uniformly distributed over the circumference of a circle perpendicular to the main axis X and centered on the main axis.

[0053] Upstream of the injection holes 38, the injection nozzle 28 forms a narrowing of the cross-section of the flow conduit 22, intended to accelerate the flow of the extinguishing agent. Thus, the injection nozzle 28 forms an acceleration zone Z2, located between the filter 26 and the injection holes 38.

[0054] To form the narrowing of the cross-section of the flow duct 22, the injection nozzle 28 comprises, in the example, an outer restriction 40, which converges towards the main axis X in the direction of flow of the extinguishing agent so as to form a narrowing of the flow duct, and an inner restriction 42, which diverges from the axis X in the direction of flow of the extinguishing agent and which is arranged in the center of the flow duct, at the outer restriction along the axis X. The inner restriction prevents the flow of the extinguishing agent in the central part of the flow duct 22, immediately upstream of the injection holes 38. It also contributes to the acceleration of the flow of the extinguishing agent in the acceleration zone Z2

[0055] The external restriction 40 corresponds in practice to the external peripheral shape of the flow duct 22 at the acceleration zone Z2, and has, in the example, a truncated cone shape with an opening angle a of between 12° and 30°, for example equal to 22°.

[0056] The internal restriction 42 is in the example a cone whose point is directed upstream of the flow conduit 22 and whose opening angle [3 is between 12° and 30°, for example equal to 24°.

[0057] The outer 40 and inner 42 restrictions together allow the flow of extinguishing agent to converge towards the injection holes 38. Furthermore, the progressive reduction in the cross-section of the flow conduit 22 caused by the restrictions 40 and 42 leads to an acceleration of the flow of the extinguishing agent, since the flow rate of the extinguishing agent is imposed on the one hand by the pressure prevailing in the tank of the extinguisher body 12 and on the other hand by the degree of opening of the trigger 16.

[0058] Downstream of the injection holes 38, the injection nozzle 28 forms a cylindrical jet-forming zone Z3. In practice, the injection nozzle comprises a cylindrical wall with a circular section 44, the internal diameter D44 of which is provided so that the injection holes 38 are tangent to the cylindrical wall 44. In other words, the flow of the extinguishing agent, on leaving the injection holes 38, is tangent to the cylindrical wall 44. The flow of the extinguishing agent thus adheres to the cylindrical wall 44, which leads to obtaining, in the zone Z3, a flow in the form of a hollow cylinder. The internal diameter D44 is preferably between 8 mm and 15 mm, for example equal to 10 mm.

[0059] The cylindrical zone Z3 extends over a length L3, measured along the main axis X, between 8 mm and 16 mm, for example equal to 12 mm. This distance is advantageously chosen to be sufficiently long to allow the formation of a cylindrical jet while remaining sufficiently short to optimize the total length of the lance 18.

[0060] Downstream of the injection nozzle 28, the flow of the extinguishing agent opens into a first foaming zone Z4. The air inlet openings 30 are provided at the first foaming zone Z4, so as to connect the outside of the lance 18 to the flow duct 22. By means of the air inlet openings 30, air located outside the lance 18 is sucked into the inside of the flow duct 22, this suction being driven by the circulation of the extinguishing agent leaving the injection nozzle 28. The air thus sucked is then mixed with the extinguishing agent, which causes the latter to foam. Thus, throughout its flow along the first foaming zone Z4, the extinguishing agent foams progressively and generates, in practice, large bubbles, for example bubbles of a larger dimension greater than 8 mm.

[0061] This foaming of the extinguishing agent is improved by the cylindrical shape of the flow leaving the injection nozzle 28, because this cylindrical shape of the flow results in a flow having a large contact surface with the air entering the flow conduit 22 through the air inlet openings 30.

[0062] In the example, the air inlet openings 30 are elongated in shape, the largest dimension of which extends parallel to the main axis X. Advantageously, the air inlet openings 30 do not extend over the entire length L4 of the first foaming zone Z4. In the example, the air inlet openings 30 extend over approximately 40% of the length L4 of the first foaming zone Z4.

[0063] Preferably, the length L4 is between 25 mm and 55 mm, for example equal to 40 mm.

[0064] Preferably, as can be seen in [Fig. 4], the air inlet openings 30 also extend upstream beyond the first foaming zone Z4, as far as the cylindrical jet-forming zone Z3. Thus, the air inlet openings 30 are partially located around the cylindrical wall 44 of the injection nozzle 28, along the main axis X.

[0065] The upstream spark gap 32 is arranged downstream of the first foaming zone Z4. It formalizes the end of the first foaming zone Z4 and the start of a second foaming zone Z5. The distance separating the upstream spark gap 32 and the downstream end of the injection nozzle 28, measured along the main axis X, therefore corresponds to the length L4 of the first foaming zone Z4.

[0066] The extinguishing agent, which flows out of the first foaming zone Z4, impacts the upstream spark gap 32, which causes mechanical mixing of the extinguishing agent. This mechanical mixing promotes the foaming of the extinguishing agent during its flow into the second foaming zone Z5, and causes the appearance of bubbles of smaller size than in the first foaming zone.

[0067] In the example, the upstream spark gap 32 is a star-shaped spark gap with three branches 32A, 32B and 32C, angularly offset uniformly, i.e. angularly offset by 120° from each other. Alternatively, the upstream spark gap 32 is a star-shaped spark gap with a different number of branches, for example four branches or six branches. The fact that the upstream spark gap 32 comprises at least three branches is particularly advantageous for optimizing the impact of the extinguishing agent against the spark gap.

[0068] According to another variant, the upstream spark gap 32 is in the form of a bar.

[0069] Advantageously, the length L4', measured along the main axis X, between the downstream end of the air inlet openings 30 and the upstream spark gap 32 is sufficiently large to prevent any backflow of the extinguishing agent through the air inlet openings 30. Thus, the impact of the flow of the extinguishing agent against the upstream spark gap 32 does not cause any leakage of extinguishing agent through the air inlet openings 30. In the example, the length L4' is approximately equal to 24 mm.

[0070] At the level of the first foaming zone Z4, the flow conduit 22 has a frustoconical shape converging in the direction of flow of the extinguishing agent, and the frustoconical shape of this zone has an opening angle yl preferably between 0.5° and 2°, for example equal to 1°.

[0071] This truncated cone shape of the flow duct makes it possible to accelerate the flow of the extinguishing agent along the first foaming zone Z4. In comparison with a cylindrical flow duct, this truncated cone shape therefore allows the extinguishing agent to strike the upstream spark gap 32 with a greater speed, thus improving the mechanical mixing of the extinguishing agent and its foaming in the second foaming zone Z5.

[0072] At the level of the second foaming zone Z5, the flow duct 22 has a frustoconical shape diverging in the direction of flow of the extinguishing agent, and the frustoconical shape of this zone has an opening angle y2 preferably between 8° and 18°, for example equal to 13°. This frustoconical shape results in a progressive increase in the cross-section of the flow duct.

[0073] When foaming, the volume of the extinguishing agent tends to increase, but this increase in volume is constrained by the dimensions of the flow conduit 22. Thus, when the extinguishing agent is prevented from increasing in volume, then its density increases, i.e. it is compressed. The divergent truncated cone shape of the second foaming zone Z5 is particularly advantageous for precisely controlling the density of the extinguishing agent foam, because it allows a controlled increase in volume of the foam and the obtaining of an optimal foam density, while limiting the pressure losses of the flow of the extinguishing agent foam.

[0074] Furthermore, the divergent shape of the second foaming zone Z5 tends to slow down the flow of extinguishing agent, which promotes the appearance of a denser foam.

[0075] The cumulative effect of the mechanical mixing caused by the upstream spark gap 32, by the slowing down of the flow of the extinguishing agent and by the increase in the density of the extinguishing agent foam, makes it possible to obtain bubbles of smaller size than in the first foaming zone Z4, for example bubbles whose largest dimension is approximately equal to 5 mm.

[0076] The combined effect of the truncated cone shapes of the foaming zones Z4 and Z5, accelerating then slowing down the flow of the extinguishing agent, therefore makes it possible to optimize the formation of foam of the extinguishing agent.

[0077] The second foaming zone Z5 extends over a length L5 of between 15 mm and 30 mm, for example equal to 20 mm.

[0078] The foaming sieve 34 is located downstream of the second foaming zone Z5. It formalizes the end of the second foaming zone Z5 and the start of a third foaming zone Z6.

[0079] The foaming sieve 34 is for example a grid whose meshes are between 1 mm by 1 mm and 5 mm by 5 mm, preferably equal to 1.5 mm by 1.5 mm.

[0080] Preferably, the foaming sieve 34 is made from a wire with a diameter approximately equal to 0.5 mm, resulting in a sieve whose openings represent between 40% and 70% of the total surface area, preferably 55% of the total surface area.

[0081] The passage of the extinguishing agent foam through the foaming screen 34 reduces the size of the foam bubbles and increases their density. Thus, at the outlet of the foaming screen 34, the largest dimension of the bubbles is for example approximately equal to 2 mm.

[0082] At the third foaming zone Z6, the flow duct 22 has a truncated cone shape extending the truncated cone shape of the second foaming zone Z5, with the same opening angle y2. The flow duct therefore has a section that increases progressively along the third foaming zone Z6, also making it possible to control the increase in volume of the foam and obtain an optimal foam density.

[0083] The third foaming zone Z6 extends over a length L6 of between 5 mm and 12 mm, for example equal to 8.5 mm.

[0084] The downstream spark gap 36 is arranged downstream of the third foaming zone Z6. It formalizes the end of the third foaming zone Z6 and the start of a jet shaping zone Z7. The distance separating the downstream end of the downstream spark gap 36 and the foaming screen 34, measured along the main axis X, therefore corresponds to the length L6 of the third foaming zone Z6.

[0085] Advantageously, the length L5 is greater than or equal to four times the length L6, preferably approximately equal to four times the length L6. In other words, the foaming screen 34 is arranged, along the axis X, closer to the downstream spark gap 36 than to the upstream spark gap 32. Moving the foaming screen 34 away from the upstream spark gap 32 is useful for obtaining satisfactory foaming of the extinguishing agent, and conversely, moving the foaming screen closer to the downstream spark gap 36 is useful for reducing the total length of the lance 18.

[0086] In the example, the downstream spark gap 36 is a star-shaped spark gap with three branches 36A, 36B, 36C, angularly offset uniformly, i.e. angularly offset by 120° from each other. Alternatively, the downstream spark gap 36 is a star-shaped spark gap with a different number of branches, for example four branches or six branches.

[0087] The jet shaping zone Z7 extends from the downstream end of the downstream spark gap 36 to the downstream end of the flow conduit 22, i.e. to the downstream end 18B of the lance 18. The jet shaping zone Z7 extends over a length L7 of between 1 mm and 10 mm, preferably equal to 5 mm.

[0088] The extinguishing agent foam, which flows out of the third foaming zone Z6 and enters the jet shaping zone Z7, impacts the downstream spark gap 36, and is thus separated into three distinct jets, each jet flowing between two adjacent branches of the downstream spark gap. In other words, the downstream spark gap 36 is intended to divide the flow of the extinguishing agent into several distinct jets.

[0089] Advantageously, this separation of the flow into three distinct jets is favored by the shape of the branches 36A, 36B, 36C of the downstream spark gap 36. Indeed, as better seen in [Fig.7], each branch of the downstream spark gap 36 has a cross-section in the shape of an isosceles triangle, a main vertex 36D of which is directed upstream of the flow conduit 22 and the base of which is directed downstream of the flow conduit. The angle 0 of the main vertex 36D is between 10° and 60° and is preferably equal to 25°.

[0090] During their flow in the jet shaping zone Z7, the three jets of extinguishing agent foam tend to diverge, moving away from the main axis X. We note q> the angle formed between the main direction of a jet of extinguishing agent foam and the main axis X, that is to say the angle of divergence of a jet of extinguishing agent foam with respect to the main axis. This divergence of the jets is notably due to the shape of the branches of the downstream spark gap 36, and continues at the outlet of the jet shaping zone Z7, that is to say at the outlet of the lance 18.

[0091] For the sake of clarity, only one of the three jets is shown in [Fig.8] at the outlet of the lance 18, corresponding to the jet flowing in the plane of the figure.

[0092] The angle 0 of the main vertex 36D of the branches 36A, 36B, 36C of the downstream spark gap 36 and the length L7 of the jet shaping zone Z7 are defined as a function of each other, because these two parameters influence the flow of the extinguishing agent foam at the outlet of the flow duct 22, and more particularly the shape of each of the three jets, as well as the degree of divergence of each of these three jets with respect to the main axis X. Advantageously, the ratio between the angle 0 and the length L7, expressed in mm^1, is between 3 and 11, preferably equal to 5. Such a ratio 0 / L7 is particularly advantageous for obtaining an optimal divergence angle q>, preferably between 10° and 25°, preferably equal to 15°.

[0093] With such a divergence angle q>, the three jets obtained at the outlet of the lance 18 are sufficiently narrowed to allow a fire to be aimed effectively and are sufficiently divergent to significantly reduce the electrical conductivity of the jets. Indeed, the lower the divergence angle q>, the more the three jets of extinguishing agent at the outlet of the lance are narrowed, being close to a cylindrical flow, which promotes the conduction of an electric current in the case where the jets are directed towards a live object. Conversely, when the divergence angle q> is high, the electrical conductivity of the jets of extinguishing agent is reduced.

[0094] Furthermore, it is particularly interesting that at the outlet of the lance 18, the flow of the extinguishing agent is divided into three or more jets, because such a division into multiple jets makes it possible to reduce the conductivity of the flow while maintaining a flow that is simple to direct towards a fire, in comparison, for example, with a flow not divided into several jets, the electrical conductivity of which would be too high, or with a flow divided into two jets, the electrical conductivity of which would be satisfactory but with which it would be complex to direct towards a fire.

[0095] Advantageously, the upstream spark gap 32 and the downstream spark gap 36 have the same number of branches, that is, in the example, three branches. Preferably, regardless of the number of branches of the upstream and downstream spark gaps, both spark gaps have the same number of branches.

[0096] As best seen in [Fig. 6], in which the foaming screen 34 is not shown for the sake of clarity, the branches 32A, 32B, 32C of the upstream spark gap 32 are angularly offset from the branches 36A, 36B, 36C of the downstream spark gap 36 around the main axis X, i.e. when considered relative to a plane perpendicular to the main axis X. In other words, the upstream and downstream spark gaps have different orientations. In the example, since each spark gap has three branches, then the branches of the upstream spark gap are offset by an angle Q1 equal to 60° relative to the branches of the downstream spark gap. This offset is particularly advantageous for improving the foaming of the extinguishing agent, since it makes it possible to obtain a more homogeneous foam, exhibiting fewer variations in density and bubble size.

[0097] Furthermore, in a particularly advantageous manner, the injection holes 38 of the injection nozzle 28 are also angularly offset from the branches of the upstream 32 and downstream 36 spark gaps around the main axis X, that is to say when considered relative to a plane perpendicular to the main axis X. Advantageously, since the injection holes 38 are uniformly distributed and since the branches of each spark gap are angularly offset from each other in a uniform manner, then the angular offset between the injection holes 38 and the branches of the upstream and downstream spark gaps is regular. In the example, since the injection nozzle comprises six injection holes, then the injection holes 38 are offset by an angle Q2 equal to 30° relative to the branches of the upstream and downstream spark gaps. The injection holes are therefore not aligned with the branches of the spark gaps.This shift also helps improve the foaming of the extinguishing agent by promoting the homogeneity of the foam obtained.

[0098] As best seen in [Fig.3], the lance 18 is in practice an assembly of several parts, comprising:

[0099] - a filter holder 46, on which the connecting thread 24 is provided, - the injection nozzle 28, - a lance body 48, which includes the upstream spark gap 32 and in which the air inlet openings 30 are provided, and - a tip 50, which includes the downstream spark gap 36.

[0100] The filter holder 46, the lance body 48 and the nozzle 50 are screwed together and the injection nozzle 28 is held in place by clamping between the filter holder and the lance body. The filter 26 is held clamped between the filter holder and the nozzle and the foaming screen 34 is held clamped between the lance body and the nozzle.

[0101] The tip 50 is shown alone in [Fig.7].

[0102] Alternatively, the lance 18 is monobloc, that is to say made in a single piece.

[0103] Preferably, the lance 18 is made of a polymer material, such as for example polyolefins, polyamide, ABS or acetal.

[0104] [Fig.8] schematically illustrates the flow of the foaming agent along the flow duct 22, representing its progressive foaming by a variable point density. In practice, at the level of zones Z1 and Z2, the extinguishing agent is liquid and does not foam, and the flow duct 22 is entirely filled with extinguishing agent. At the level of the cylindrical zone Z3, the extinguishing agent foams slightly and forms a hollow cylindrical jet not entirely filling the flow duct 22. The foaming of the extinguishing agent continues in the zone Z4, corresponding to the entry of air through the air inlet openings 30, shown diagrammatically by two arrows F and to the mixing of the air with the extinguishing agent. In this zone, the bubbles obtained are large. In zone Z5, after passing the upstream spark gap 32, foaming continues, with smaller bubbles.In zone Z6, after passing through the foaming screen 34, the bubbles decrease in size again. Zone Z7 then forms the jet exiting the lance 18, separating the flow into three separate jets using the downstream spark gap 36.

[0105] The lance 18 is particularly advantageous because it allows the use of a fluorine-free extinguishing agent without loss of performance, i.e. without reducing the capacity of the extinguisher 10 to effectively extinguish class A and class B fires.

[0106] In particular, the presence of two spark gaps arranged on either side of the foaming screen is particularly effective in obtaining both effective foaming of the extinguishing agent and a shape of the flow at the outlet of the lance giving the extinguisher 10 good extinguishing performance. This foaming is optimized by the positioning inside the flow duct 22 of the upstream 32 and downstream 36 spark gaps and the foaming screen 34, by the shape of the flow duct, in particular at the foaming zones Z4 and Z5, and by the angular offset of the injection holes 38 and the upstream and downstream spark gaps. The shape of the flow at the outlet of the lance is further improved by the triangular section of the branches 36A, 36B, 36C of the downstream spark gap 36 and by the length L7 between the downstream end of the downstream spark gap and the downstream end 18B of the lance 18.The fact that the flow at the outlet of the lance comprises three distinct jets, or more when the downstream extinguisher 36 comprises a number of branches greater than three, makes it easier for a responder to aim a fire while reducing the electrical conductivity of the flow, thus reducing the risks of electrocution of the responder.

[0107] For example, the extinguisher 10 equipped with the lance 18 can extinguish class B fires up to a type 233B fire source as defined by the NF EN 3-7 standard. A type 233B fire source corresponds to a fire started in a round container with a diameter equal to 3 m, filled with a 2 cm layer of liquid heptane placed on a 1 cm layer of water.

[0108] In addition, the extinguisher 10 equipped with the lance 18 can extinguish class A fires up to a type 55A fire as defined by the NF EN 3-1 standard. A type 55A fire corresponds to a parallelepiped-shaped fire of pine logs measuring 5.5 m x 0.55 m x 0.50 m.

[0109] When the extinguisher 10 is used in the context of a so-called “dielectric” test, as defined by the NF EN 3-7 standard, consisting of placing the lance 18 at a distance of one meter from a square plate of 1m x 1m brought to an electrical potential of 35kV, then actuating the handle 20 and the trigger 16 so as to completely empty the extinguisher against the plate, while measuring the electric current flowing between the extinguisher and the earth via the lance, then the measured current is less than 0.5 mA.

[0110] Alternatively, the lance 18 does not include a connecting thread 24, and is assembled with the socket 15 by other means, for example by crimping or by heat welding.

[0111] Alternatively, the filter 26 is not located in the lance 18, but in the socket 15, in the flexible pipe 14 or in the extinguisher body 12.

[0112] Alternatively, the injection nozzle 28 comprises a number of injection holes 38 other than six, for example three injection holes.

[0113] Preferably, and regardless of the number of injection holes 38, the injection holes are angularly offset from the branches of the upstream and downstream spark gaps in a regular manner. Advantageously, regardless of the number of injection holes 38, the sum of the section of the injection holes is between 5.5 mm2 and 10 mm2, preferably equal to 8 mm2

[0114] Alternatively, the branches of the downstream spark gap 36 are not triangular in section, but have another point-shaped section, comprising a point directed upstream of the flow conduit 22 and a base directed downstream of the flow conduit.

[0115] Any feature described for one embodiment or variation in the foregoing may be implemented for the other embodiments and variations described above, as long as technically feasible.

Claims

Claims

1. Lance (18) for a fire extinguisher (10), intended for the projection and foaming of a fluorine-free extinguishing agent, the lance defining a flow duct (22) of the extinguishing agent extending along a main axis (X), the lance comprising, in the direction of flow of the extinguishing agent along the main axis: - an injection nozzle (28) comprising at least two injection holes (38); - at least one air inlet opening (30) connecting the outside of the lance (18) to the flow duct (22), the air inlet opening being intended to suck air from the outside of the lance towards the inside of the flow duct, so as to allow the foaming of the extinguishing agent by mixing with the air; - a foaming sieve (34), intended to improve the foaming of the extinguishing agent;and - a downstream spark gap (36), intended to divide the flow of the extinguishing agent into several separate jets, characterized in that - the downstream spark gap (36) comprises at least three branches (36A, 36B, 36C), and - the lance (18) further comprises an upstream spark gap (32), located between the air inlet opening (30) and the foaming screen (34).;

2. Lance (18) according to claim 1, in which the upstream spark gap (32) and the downstream spark gap (36) comprise the same number of branches and in which the branches (36A, 36B, 36C) of the downstream spark gap are angularly offset from the branches (32A, 32B, 32C) of the upstream spark gap, around the main axis (X).

3. Lance (18) according to claim 2, in which the injection holes (38) of the injection nozzle (28) are angularly offset, around the main axis (X), of the branches (32A, 32B, 32C) of the upstream spark gap (32) and of the branches (36A, 36B, 36C) of the downstream spark gap (34).

4. A lance (18) according to any preceding claim, in in which the sum of the section of the injection holes (38) is between 5.5 mm2 and 10 mm2, preferably equal to 8 mm2, the section of each injection hole being measured perpendicular to the main axis (X), and in which, preferably, the injection nozzle (28) comprises six injection holes (38).

5. Lance (18) according to any one of the preceding claims, wherein the injection nozzle (28) comprises, upstream of the injection holes (38): - an outer restriction (40), which converges towards the main axis (X) in the direction of flow of the extinguishing agent and which forms a narrowing of the flow duct (22), and - an inner restriction (42), arranged in the center of the flow duct (22), which diverges from the main axis (X) in the direction of flow of the extinguishing agent and which forms a narrowing of the flow duct (22), wherein the outer restriction (40) and the inner restriction (42) are configured to accelerate the flow of the extinguishing agent and to converge the flow of the extinguishing agent towards the injection holes (38) and wherein, preferably, the outer restriction has a truncated cone shape and the inner restriction is a cone.

6. Lance (18) according to any one of the preceding claims, wherein each branch (36A, 36B, 36C) of the downstream spark gap (36) has a tip-shaped section, one tip of which is directed upstream of the flow conduit (22), wherein, preferably, the tip-shaped section of each branch of the downstream spark gap is an isosceles triangle-shaped section, and wherein, preferably, an angle (0) of a main vertex (36D) of the tip-shaped section is between 10° and 60°, more preferably equal to 25°.

7. Lance (18) according to any one of the preceding claims, in which a length (L7), measured along the main axis (X), between a downstream end of the downstream spark gap (36) and a downstream end (18A) of the lance (18) is between 1 mm and 10 mm, preferably equal to 5 mm.

8. A lance (18) according to any preceding claim, wherein a length (L5) between the upstream spark gap (32) and the screen foaming (34) is greater than or equal to four times a length (L6) between the foaming screen and a downstream end of the downstream spark gap (36), the lengths being measured along the main axis (X).

9. A lance (18) according to any preceding claim, wherein, from the injection nozzle (28) to the upstream spark gap (32), the flow conduit (22) has a frustoconical shape which converges in the direction of flow of the extinguishing agent, and wherein, from the upstream spark gap (32) to the foaming screen (34), the flow conduit has a frustoconical shape which diverges in the direction of flow of the extinguishing agent.

10. Fire extinguisher (10) comprising a fire extinguisher body (12), a flexible hose (14) and a lance (18), the fire extinguisher body comprising a bottle of extinguishing agent, characterized in that the lance (18) is according to any one of the preceding claims, and in that the fire extinguisher (10) comprises a filter (26) located upstream of the injection nozzle (28) and intended to filter any impurities present in the extinguishing agent, this filter being arranged in the lance (18) or upstream thereof.

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