Lance for fire extinguisher and fire extinguisher comprising such a lance

Abstract

A fire extinguisher nozzle (18) is intended for the projection and foaming of a fluorine-free extinguishing agent. The nozzle defines a flow channel (22) and includes, 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 nozzle to the flow channel, intended to draw air from the outside of the nozzle into the inside of the flow channel, 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 nozzle (36), intended to divide the flow of the extinguishing agent into several distinct jets. To improve the foaming of the extinguishing agent, the downstream nozzle includes at least three arms and the nozzle further includes an upstream nozzle (32), located between the air inlet opening and the foaming sieve.

Description

[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 common to use extinguishers that project an extinguishing agent composed of a mixture of water and a surfactant, which foams during its projection, to extinguish Class A and Class B fires. These fire classes are defined by the NF EN 2 standard. Such an extinguisher generally comprises a body, a flexible hose, and a nozzle. The passage of the extinguishing agent through the nozzle causes it to foam. The performance of fire extinguishers is linked to the suitability of the extinguishing agent for the nozzle, as each extinguishing agent has a varying foaming capacity depending on the nozzle used.

[0003] The surfactant additive used in the extinguishing agent usually contains fluorine, which gives the agent good foaming properties. Since such an extinguishing agent is easy to foam, the design of the associated nozzles is relatively simple, and the resulting extinguishers can be used interchangeably on Class A and Class B fires. These extinguishers are generally satisfactory, but lead to environmental pollution due to the use of fluorine.

[0004] US document 3,388,868 A describes an example of a nozzle that can be used with such an extinguishing agent.

[0005] It is also known to use an extinguishing agent whose surfactant additive does not contain fluorine. However, using such a fluorine-free extinguishing agent with known nozzles is not satisfactory, as these nozzles do not allow for effective foaming of the extinguishing agent. Therefore, the performance of the extinguishers is reduced when using a fluorine-free extinguishing agent.

[0006] To compensate for this reduced performance, BE-A-1028003, which describes the use of a fluorine-free extinguishing agent, proposes two different nozzles, one for extinguishing Class A fires and the other for extinguishing Class B fires. Each nozzle is specifically designed to improve the foaming of the extinguishing agent according to the fire class to be extinguished. Therefore, the performance of extinguishers using these nozzles is reduced, as they cannot be used interchangeably on both Class A and Class B fires.

[0007] 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.

[0008] The invention specifically aims to address this need by proposing a new, more efficient fire extinguisher lance when a fluorine-free agent is used.

[0009] To this end, the invention relates to a fire extinguisher nozzle intended for the projection and foaming of a fluorine-free extinguishing agent, the nozzle defining a flow conduit for the extinguishing agent extending along a principal axis, the nozzle comprising, in the direction of the flow of the extinguishing agent along the principal axis: an injection nozzle comprising at least two injection holes; at least one air inlet opening connecting the outside of the nozzle to the flow duct, the air inlet opening being intended to draw air from the outside of the nozzle into the inside of the flow duct, so as to permit the foaming of the extinguishing agent by mixing with the air; a foaming screen, intended to improve the foaming of the extinguishing agent; and a downstream burster, intended to divide the flow of the extinguishing agent into several separate jets.

[0010] According to the invention, the downstream burster is star-shaped with at least three branches, angularly offset uniformly around the main axis (X), and the lance further includes an upstream burster, located between the air inlet opening and the foaming screen.

[0011] Thanks to the invention, the presence of two nozzles, positioned on either side of the foaming screen, allows for efficient foaming of the extinguishing agent without causing significant pressure losses or backflow of the extinguishing agent through the air inlet openings. Furthermore, the three arms of the downstream nozzle produce a jet of foamed extinguishing agent with characteristics, such as the shape and density of the foam, suitable for extinguishing Class A and B fires.

[0012] According to advantageous, but not mandatory, aspects of the invention, the fire extinguisher nozzle incorporates one or more of the following features, taken individually or in any technically permissible combinations: The upstream and downstream spark gaps have the same number of branches, and the branches of the downstream spark gap are angularly offset from the branches of the upstream spark gap about the main axis. The injection holes of the injection nozzle are angularly offset, about the main axis, from the branches of the upstream and downstream spark gaps. The sum of the cross-sectional areas of the injection holes is between 5.5 mm² and 10 mm², preferably equal to 8 mm², the cross-section of each injection hole being measured perpendicular to the main axis, and preferably, the injection nozzle comprises six injection holes.The injection nozzle includes, upstream of the injection holes, an outer restriction that converges toward the main axis in the direction of the extinguishing agent flow and forms a constriction in the flow channel, and an inner restriction, located at the center of the flow channel, that diverges from the main axis in the direction of the extinguishing agent flow and also forms a constriction in the flow channel. The outer and inner restrictions are configured to accelerate the flow of the extinguishing agent and to direct its flow toward the injection holes. Preferably, the outer restriction is truncated cone-shaped and the inner restriction is cone-shaped. Each branch of the downstream burst has a pointed cross-section, one point of which is directed upstream of the flow channel.Preferably, the pointed cross-section of each branch of the downstream burster is an isosceles triangle. Preferably, an angle of a principal vertex of the pointed cross-section is between 10° and 60°, preferably 25°. A length, measured along the principal axis, between a downstream end of the downstream burster and a downstream end of the nozzle is between 1 mm and 10 mm, preferably 5 mm. A length between the upstream burster and the foaming screen is greater than or equal to four times a length between the foaming screen and a downstream end of the downstream burster, the lengths being measured along the principal axis.From the injection nozzle to the upstream burster, the flow conduit has a frustoconical shape that converges in the direction of the flow of the extinguishing agent, and, from the upstream burster to the foaming sieve, the flow conduit has a frustoconical shape that diverges in the direction of the flow of the extinguishing agent.

[0013] In another aspect, the invention also relates to a fire extinguisher comprising a body, a flexible hose, and a nozzle, the body containing a bottle of extinguishing agent. According to the invention, the nozzle is as described above. Furthermore, the extinguisher includes a filter located upstream of the injection nozzle for filtering out any impurities present in the extinguishing agent, this filter being disposed in or upstream of the nozzle.

[0014] This fire extinguisher provides the same advantages as those mentioned above regarding the lance of the invention.

[0015] The invention will be better understood and other advantages thereof will become more apparent in the light of the following description of an embodiment of a fire extinguisher nozzle and of a fire extinguisher given solely by way of example and made with reference to the accompanying drawings in which: [ Fig. 1 ] There figure 1 is a perspective view of a fire extinguisher according to the invention; [ Fig. 2 ] There figure 2 is a perspective view of a nozzle belonging to the fire extinguisher of the figure 1 , the spear conforming to the invention; Fig. 3 ] There figure 3 is an exploded perspective view of the spear of the figure 2 ; Fig. 4 ] There figure 4 is a longitudinal section of the spear of figures 2 And 3 , according to plan IV of the figure 2 ; Fig. 5 ] There figure 5 is a cross-section of the spear of figures 2 à 4 , according to plan V of the figure 4 ; Fig. 6 ] There figure 6 is a view from downstream of the lance of the figures 2 à 5 , in the direction of arrow F6 at the figure 2 ; Fig. 7 ] There figure 7 is a longitudinal section of a tip belonging to the lance of the figures 2 à 6 , according to plan VII of the figure 3 ; And [ Fig. 8 ] There figure 8 is a similar cut figure 4 , on which the flow of an extinguishing agent through the nozzle is represented.

[0016] A fire extinguisher 10 is shown at the figure 1 The 10 fire extinguisher is a portable fire extinguisher of the water mist type with additive, or of the foam type. The 10 fire extinguisher is intended to extinguish class A fires, i.e., dry fires, in other words, fires of solid materials whose combustion produces embers, such as wood, and class B fires, i.e., grease fires, in other words, fires involving liquids and liquefiable solids, such as hydrocarbons or greases.

[0017] To extinguish class A and B fires, the extinguisher 10 uses a liquid extinguishing agent composed of a mixture of water and surfactant additive, which is sprayed using a propellant.

[0018] The fire extinguisher 10 comprises a fire extinguisher body 12, a flexible hose 14, a socket 15 equipped with a trigger 16 and a nozzle 18. The socket 15 is intended to be grasped by a user to direct the nozzle 18 towards the base of the flames and to operate the trigger.

[0019] As is known, the body of the fire extinguisher 12 forms a reservoir that is filled with water and also includes a bottle of surfactant additive, which in this example is a fluorine-free surfactant. Therefore, in this example, the extinguishing agent formed by the mixture of water and the surfactant additive is a fluorine-free extinguishing agent.

[0020] Preferably, the reservoir of the extinguisher body 12 is designed to hold 6 liters (L) of extinguishing agent, or 9 L of extinguishing agent. When the reservoir is designed to hold 6 L of extinguishing agent, this extinguishing agent is, for example, composed of approximately 5.9 L of water and approximately 0.1 L of fluorine-free surfactant additive.

[0021] The fire extinguisher 10 also includes a handle 20, designed so that its actuation causes the surfactant additive to mix with water, thus forming an extinguishing agent, and the extinguishing agent to be propelled, in liquid form, from the extinguisher body 12 to the nozzle 18 via the flexible hose 14.

[0022] Alternatively, the extinguisher body does not include a surfactant additive bottle, and the surfactant additive is then mixed with the water filling the reservoir at the time of manufacture of the extinguisher 10.

[0023] As is known, the extinguishing agent body 12 can be "permanently pressurized," meaning that the water filling the reservoir is constantly under pressure, or the extinguishing agent body may contain a propellant cartridge, such as CO2, the release of which into the extinguishing agent body causes the reservoir to pressurize. When the extinguishing agent body 12 contains a propellant cartridge, then actuating the handle 20 causes the propellant cartridge to be punctured.

[0024] The trigger 16, mounted on the socket 15 between the flexible hose 14 and the nozzle 18, allows the flow of the extinguishing agent through the nozzle 18 to be authorized or interrupted. When it arrives in the nozzle 18, the extinguishing agent is in liquid form, and its passage through the nozzle 18 causes it to foam, thus improving its fire-extinguishing properties.

[0025] Thus, at the exit of lance 18, the extinguishing agent is in the form of a foam, allowing to effectively extinguish class A and B fires.

[0026] As more clearly visible on the figures 2 à 4 The nozzle 18 defines a flow conduit 22 for the extinguishing agent. The nozzle 18 extends along a principal axis X. In the following description, the terms "upstream" and "downstream" are understood relative to the principal axis X and refer to the direction of flow of the extinguishing agent inside the flow conduit 22. The upstream end of the nozzle 18 is denoted 18A and the downstream end of the nozzle is denoted 18B.

[0027] In the direction of the flow of the extinguishing agent, i.e. from its upstream end 18A to its downstream end 18B, the nozzle 18 comprises the following elements: a connecting thread 24; a filter 26; an injection nozzle 28; one or more air inlet openings 30 connecting the outside of the lance 18 to the inside of the flow duct 22, in the example four air inlet openings; an upstream burster 32; a foaming screen 34; and a downstream burster 36.

[0028] 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.

[0029] The connecting thread 24 allows the nozzle 18 to be connected to the socket 15 by screwing it in. Thus, the socket 15 and the nozzle 18 are rigidly joined, so that a user of the fire extinguisher 10 can direct the nozzle 18 towards a fire by manipulating the socket 15.

[0030] In practice, the connecting thread 24 is arranged, along the main axis X, at the level of an inlet zone Z1 of the flow conduit 22.

[0031] Filter 26 is intended to filter out any impurities present in the extinguishing agent coming from the extinguishing body 12. Filter 26 is, in this example, a grid with 1 mm by 1 mm mesh.

[0032] As more clearly seen on the figure 5 The injection nozzle 28 has several injection holes 38, in the example six injection holes 38. Advantageously, the sum of the cross-sectional areas of the injection holes 38 is between 5.5 mm² and 10 mm², preferably equal to 8 mm², the cross-section of each injection hole being measured perpendicular to the principal X axis. In the example, the diameter of each injection hole 38 is 1.3 mm. The center of each injection hole 38 is located at a distance from the principal X axis, for example, 4.3 mm from the principal Z axis. Furthermore, the injection holes are preferably uniformly distributed around the circumference of a circle perpendicular to the principal X axis and centered on the principal axis.

[0033] Upstream of the injection holes 38, the injection nozzle 28 forms a narrowing in the cross-section of the flow conduit 22, designed 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.

[0034] To create the constriction in the cross-section of the flow conduit 22, the injection nozzle 28 comprises, in this example, an outer restriction 40, which converges towards the main axis X in the direction of the extinguishing agent flow so as to form a constriction in the flow conduit, and an inner restriction 42, which diverges from the axis X in the direction of the extinguishing agent flow and is located in the center of the flow conduit, at the level of the outer restriction along the axis X. The inner restriction prevents the extinguishing agent from flowing into the central part of the flow conduit 22, immediately upstream of the injection holes 38. It also contributes to accelerating the flow of the extinguishing agent in the acceleration zone Z2.

[0035] The external restriction 40 corresponds in practice to the external peripheral shape of the flow conduit 22 at the level of the acceleration zone Z2, and has, in the example, a truncated cone shape with an opening angle α between 12° and 30°, for example equal to 22°.

[0036] The internal restriction 42 is in the example a cone whose tip is directed upstream of the flow conduit 22 and whose opening angle β is between 12° and 30°, for example equal to 24°.

[0037] The external restriction 40 and internal restriction 42 together allow the flow of the extinguishing agent to converge towards the injection holes 38. In addition, the progressive decrease 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, because the flow rate of the extinguishing agent is imposed on the one hand by the pressure prevailing in the reservoir of the extinguishing body 12 and on the other hand by the degree of opening of the trigger 16.

[0038] 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 cross-section 44, the internal diameter of which D44 is designed so that the injection holes 38 are tangent to the cylindrical wall 44. In other words, the flow of the extinguishing agent, exiting the injection holes 38, is tangent to the cylindrical wall 44. The flow of the extinguishing agent thus adheres to the cylindrical wall 44, resulting in a hollow cylinder-shaped flow in zone Z3. The internal diameter D44 is preferably between 8 mm and 15 mm, for example, 10 mm.

[0039] The cylindrical zone Z3 extends over a length L3, measured along the principal axis X, of between 8 mm and 16 mm, for example equal to 12 mm. This distance is advantageously chosen to be long enough to allow the formation of a cylindrical jet while remaining short enough to optimize the total length of the lance 18.

[0040] Downstream of the injection nozzle 28, the extinguishing agent flows into a first foaming zone Z4. Air inlet openings 30 are provided at the level of the first foaming zone Z4, so as to connect the outside of the nozzle 18 to the flow duct 22. Through the air inlet openings 30, air located outside the nozzle 18 is drawn into the flow duct 22, this aspiration being driven by the circulation of the extinguishing agent exiting the injection nozzle 28. The air thus drawn in 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 larger than 8 mm.

[0041] This foaming of the extinguishing agent is improved by the cylindrical shape of the flow at the outlet of the injection nozzle 28, because this cylindrical shape of the flow results in a flow having a large surface area of ​​contact with the air entering the flow duct 22 through the air inlet openings 30.

[0042] In the example, the air inlet openings 30 are elongated, with their longest dimension extending parallel to the principal axis X. Advantageously, the air inlet openings 30 do not extend along 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.

[0043] Preferably, the length L4 is between 25 mm and 55 mm, for example equal to 40 mm.

[0044] Preferably, as can be seen on the figure 4 The air inlet openings 30 also extend upstream beyond the first foaming zone Z4, to the cylindrical jet formation 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.

[0045] The upstream burster 32 is located downstream of the first foaming zone Z4. It marks the end of the first foaming zone Z4 and the beginning of a second foaming zone Z5. The distance between the upstream burster 32 and the downstream end of the injection nozzle 28, measured along the principal axis X, therefore corresponds to the length L4 of the first foaming zone Z4.

[0046] The extinguishing agent, flowing out of the first foaming zone Z4, impacts the upstream nozzle 32, causing mechanical mixing of the extinguishing agent. This mechanical mixing promotes foaming of the extinguishing agent as it flows into the second foaming zone Z5, resulting in the formation of smaller bubbles than in the first foaming zone.

[0047] In the example, the upstream burst 32 is a three-pronged star-shaped burst with prongs 32A, 32B, and 32C, uniformly offset angularly, i.e., 120° apart. Alternatively, the upstream burst 32 is a star-shaped burst with a different number of prongs, for example, four or six. Having at least three prongs in the upstream burst 32 is particularly advantageous for optimizing the impact of the extinguishing agent on the burst.

[0048] According to another variant, the upstream spark gap 32 is bar-shaped.

[0049] Advantageously, the length L4', measured along the principal axis X, between the downstream end of the air inlet openings 30 and the upstream burst 32 is sufficiently large to prevent any reflux of the extinguishing agent through the air inlet openings 30. Thus, the impact of the flow of the extinguishing agent against the upstream burst 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.

[0050] At the level of the first foaming zone Z4, the flow conduit 22 has a truncated conical shape converging in the direction of the flow of the extinguishing agent, and the truncated conical shape of this zone has an opening angle γ1 preferably between 0.5° and 2°, for example equal to 1°.

[0051] This truncated conical shape of the flow duct accelerates the flow of the extinguishing agent along the first foaming zone Z4. Compared to a cylindrical flow duct, this truncated conical shape allows the extinguishing agent to strike the upstream burst 32 at a higher speed, thus improving the mechanical mixing of the extinguishing agent and its foaming in the second foaming zone Z5.

[0052] At the level of the second foaming zone Z5, the flow conduit 22 has a frustoconical shape diverging in the direction of the flow of the extinguishing agent, and the frustoconical shape of this zone has an opening angle γ2 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 conduit.

[0053] During foaming, the volume of the extinguishing agent tends to increase, but this increase is constrained by the dimensions of the flow duct 22. Thus, when the extinguishing agent is prevented from expanding, its density increases, meaning it is compressed. The diverging truncated cone shape of the second foaming zone Z5 is particularly advantageous for precisely controlling the density of the extinguishing agent foam, as it allows for a controlled increase in foam volume and the achievement of optimal foam density, while limiting pressure losses in the flow of the extinguishing agent foam.

[0054] In addition, the divergent shape of the second foaming zone Z5 tends to slow the flow of extinguishing agent, which promotes the appearance of a denser foam.

[0055] The cumulative effect of the mechanical mixing caused by the upstream burster 32, by the slowing 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 about equal to 5 mm.

[0056] The combined effect of the truncated conical shapes of the foaming zones Z4 and Z5, accelerating and then slowing down the flow of the extinguishing agent, therefore optimizes the formation of foam from the extinguishing agent.

[0057] The second foaming zone Z5 extends over a length L5 between 15 mm and 30 mm, for example equal to 20 mm.

[0058] The foaming screen 34 is located downstream of the second foaming zone Z5. It marks the end of the second foaming zone Z5 and the beginning of a third foaming zone Z6.

[0059] The foaming sieve 34 is for example a grid whose mesh size is between 1 mm by 1 mm and 5 mm by 5 mm, preferably equal to 1.5 mm by 1.5 mm.

[0060] Preferably, the foaming sieve 34 is made from a wire with a diameter of approximately 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.

[0061] Passing the extinguishing agent foam through the foaming sieve 34 reduces the size of the foam bubbles and increases their density. Thus, at the outlet of the foaming sieve 34, the largest dimension of the bubbles is, for example, approximately 2 mm.

[0062] At the third foaming zone Z6, the flow duct 22 has a frustoconical shape that extends the frustoconical shape of the second foaming zone Z5, with the same opening angle γ2. The flow duct therefore has a cross-section that gradually increases along the third foaming zone Z6, also allowing control of the foam volume increase and the achievement of an optimal foam density.

[0063] The third foaming zone Z6 extends over a length L6 between 5 mm and 12 mm, for example equal to 8.5 mm.

[0064] The downstream burster 36 is located downstream of the third foaming zone Z6. It marks the end of the third foaming zone Z6 and the beginning of a jet shaping zone Z7. The distance between the downstream end of the downstream burster 36 and the foaming screen 34, measured along the principal axis X, therefore corresponds to the length L6 of the third foaming zone Z6.

[0065] 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 positioned, along the X-axis, closer to the downstream nozzle 36 than to the upstream nozzle 32. Moving the foaming screen 34 further from the upstream nozzle 32 is useful for obtaining satisfactory foaming of the extinguishing agent, and conversely, moving the foaming screen closer to the downstream nozzle 36 is useful for reducing the overall length of the nozzle 18.

[0066] 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 or six branches.

[0067] The jet shaping zone Z7 extends from the downstream end of the downstream burster 36 to the downstream end of the flow conduit 22, i.e. to the downstream end 18B of the nozzle 18. The jet shaping zone Z7 extends over a length L7 of between 1 mm and 10 mm, preferably equal to 5 mm.

[0068] The extinguishing agent foam, flowing out of the third foaming zone Z6 and into the jet shaping zone Z7, impacts the downstream nozzle 36, thus separating it into three distinct jets, each jet flowing between two adjacent branches of the downstream nozzle. In other words, the downstream nozzle 36 is designed to divide the flow of the extinguishing agent into several separate jets.

[0069] Advantageously, this separation of the flow into three distinct jets is facilitated by the shape of the branches 36A, 36B, 36C of the downstream spark gap 36. Indeed, as more clearly seen at the figure 7 Each branch of the downstream bursting device 36 has an isosceles triangular cross-section, with a principal vertex 36D directed upstream of the flow conduit 22 and a base directed downstream of the flow conduit. The angle θ of the principal vertex 36D is between 10° and 60° and is preferably equal to 25°.

[0070] During their flow through the jet conformation zone Z7, the three extinguishing agent foam jets tend to diverge, moving away from the principal axis X. Let φ be the angle formed between the principal direction of an extinguishing agent foam jet and the principal axis X, that is, the divergence angle of an extinguishing agent foam jet with respect to the principal axis. This divergence of the jets is primarily due to the shape of the branches of the downstream nozzle 36 and continues beyond the jet conformation zone Z7, that is, beyond the nozzle 18.

[0071] For the sake of clarity, only one of the three jets is shown on the figure 8 at the outlet of lance 18, corresponding to the jet flowing in the plane of the figure.

[0072] The angle θ of the main apex 36D of the branches 36A, 36B, 36C of the downstream burster 36 and the length L7 of the jet conformation zone Z7 are defined as a function of each other, since 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 θ and the length L7, expressed in mm⁻¹, is between 3 and 11, preferably equal to 5. Such a ratio θ / L7 is particularly advantageous for obtaining an optimal divergence angle φ, preferably between 10° and 25°, preferably equal to 15°.

[0073] With such a divergence angle φ, the three jets exiting the nozzle 18 are sufficiently concentrated to effectively target a fire and sufficiently divergent to significantly reduce their electrical conductivity. Indeed, the smaller the divergence angle φ, the more concentrated the three jets of extinguishing agent exiting the nozzle become, approaching a cylindrical flow, which promotes the conduction of an electric current when the jets are directed towards a live object. Conversely, when the divergence angle φ is large, the electrical conductivity of the extinguishing agent jets is reduced.

[0074] Furthermore, it is particularly interesting that at the outlet of nozzle 18, the extinguishing agent flow 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 simple flow to direct towards a fire, in comparison, for example, with a flow not divided into several jets, whose electrical conductivity would be too high, or with a flow divided into two jets, whose electrical conductivity would be satisfactory but with which it would be complex to direct towards a fire.

[0075] 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.

[0076] As more clearly seen on the figure 6 In the diagram, where the foaming sieve 34 is not shown for clarity, the arms 32A, 32B, and 32C of the upstream sputter 32 are angularly offset from the arms 36A, 36B, and 36C of the downstream sputter 36 around the principal axis X, that is, when considered relative to a plane perpendicular to the principal axis X. In other words, the upstream and downstream sputters have different orientations. In this example, since each sputter has three arms, the arms of the upstream sputter are offset by an angle Ω1 of 60° relative to the arms of the downstream sputter. This offset is particularly advantageous for improving the foaming of the extinguishing agent, as it results in a more homogeneous foam with fewer variations in density and bubble size.

[0077] Furthermore, and particularly advantageously, 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 principal axis X, that is, when considered relative to a plane perpendicular to the principal 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 uniformly, 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, the injection holes 38 are offset by an angle Ω2 of 30° with respect 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 offset also helps to improve the foaming of the extinguishing agent by promoting the homogeneity of the foam obtained.

[0078] As more clearly seen on the figure 3 The spear 18 is, in practice, an assembly of several parts, including: a filter holder 46, on which is provided the connection thread 24, the injection nozzle 28, a lance body 48, which includes the upstream burster 32 and in which are provided the air inlet openings 30, and a nozzle 50, which includes the downstream burster 36.

[0079] 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 tightly between the filter holder and the nozzle, and the foaming screen 34 is held tightly between the lance body and the nozzle.

[0080] The 50 mm tip is shown alone at the figure 7 .

[0081] Alternatively, lance 18 is monobloc, that is to say made in one piece.

[0082] Preferably, lance 18 is made of a polymer material, such as polyolefins, polyamide, ABS or acetal.

[0083] There figure 8This diagram schematically illustrates the flow of the foaming agent along the flow duct 22, representing its progressive foaming by a varying point density. In practice, at zones Z1 and Z2, the extinguishing agent is liquid and does not foam, and the flow duct 22 is completely filled with extinguishing agent. At the cylindrical zone Z3, the extinguishing agent foams slightly and forms a hollow cylindrical jet that does not completely fill the flow duct 22. The foaming of the extinguishing agent continues in zone Z4, corresponding to the air intake through the air inlet openings 30, schematically represented by two arrows F, and the mixing of the air with the extinguishing agent. In this zone, the resulting bubbles are large. In zone Z5, after the passage of the upstream burster 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 distinct jets by means of the downstream burster 36.

[0084] 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 ability of the extinguisher 10 to effectively extinguish class A and class B fires.

[0085] In particular, the presence of two nozzles positioned on either side of the foaming screen is especially effective in achieving both efficient foaming of the extinguishing agent and a flow pattern at the nozzle outlet that gives the extinguisher 10 good extinguishing performance. This foaming is optimized by the positioning within the flow channel 22 of the upstream nozzles 32 and downstream nozzles 36 and of the foaming screen 34, by the shape of the flow channel, particularly at the foaming zones Z4 and Z5, and by the angular offset of the injection holes 38 and the upstream and downstream nozzles. The shape of the flow exiting the nozzle is further improved by the triangular section of the branches 36A, 36B, 36C of the downstream burster 36 and by the length L7 between the downstream end of the downstream burster and the downstream end 18B of the nozzle 18.The fact that the flow exiting the nozzle comprises three distinct jets, or more when the downstream extinguisher 36 comprises more than three branches, facilitates aiming at a fire by an responder while reducing the electrical conductivity of the flow, thus reducing the risk of electrocution of the responder.

[0086] For example, the 10 fire extinguisher equipped with the 18 nozzle can extinguish class B fires up to a type 233B fire as defined by the NF EN 3-7 standard. A type 233B fire corresponds to a fire started in a round container with a diameter of 3 m, filled with a 2 cm layer of liquid heptane placed on a 1 cm layer of water.

[0087] Furthermore, the 10 fire extinguisher equipped with the 18 nozzle allows for the extinguishing of 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 × 0.55 m × 0.50 m.

[0088] When the fire extinguisher 10 is used in the context of a so-called "dielectric" test, as defined by the standard NF EN 3-7, consisting of placing the nozzle 18 at a distance of one meter from a 1m × 1m square plate brought to an electrical potential of 35kV, then actuating the handle 20 and the trigger 16 so as to completely empty the fire extinguisher against the plate, while measuring the electric current flowing between the fire extinguisher and the earth via the nozzle, then the measured current is less than 0.5 mA.

[0089] 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.

[0090] Alternatively, the filter 26 is not located in the lance 18, but in the socket 15, in the flexible hose 14 or in the extinguisher body 12.

[0091] Alternatively, the injection nozzle 28 includes a number of injection holes 38 other than six, for example three injection holes.

[0092] Preferably, and regardless of the number of injection holes 38, the injection holes are angularly offset from the branches of the upstream and downstream bursts in a regular manner. Advantageously, regardless of the number of injection holes 38, the sum of the cross-sectional areas of the injection holes is between 5.5 mm² and 10 mm², preferably equal to 8 mm².

[0093] Alternatively, the branches of the downstream burster 36 are not triangular in cross-section, but have another pointed cross-section, comprising a point directed upstream of the flow conduit 22 and a base directed downstream of the flow conduit.

[0094] As can be seen from the above, a burster, such as the upstream burster 32 or the downstream burster 36, differs structurally and functionally from a foaming screen, such as the foaming screen 34, for several reasons.

[0095] First, a foam sieve is generally formed by a grid or another structure with a fine mesh. In a typical example, where the foam sieve has a diameter of 27 mm and a mesh size of 1.5 mm by 1.5 mm, the sieve has approximately 200 openings. A flow passing through a foam sieve therefore passes through the multiple openings of the grid, which prevents the passage of large air bubbles and thus reduces the size of the bubbles in the extinguishing agent foam. Indeed, the maximum bubble size exiting the foam sieve is of the same order of magnitude as the mesh size. In other words, a foam sieve filters out large air bubbles. The role of the foam sieve 34 is therefore to improve the quality of the extinguishing agent foam by reducing the size of the foam bubbles and increasing their density.Furthermore, the large number of openings in the foaming screen makes it impossible to distinguish jets that are clearly distinct from one another after the flow has passed through the foaming screen.

[0096] Conversely, a nozzle presents few obstacles to the flow of the jet. In the preceding preferential example, the upstream and downstream nozzles each have three branches. Therefore, a nozzle does not filter air bubbles from the extinguishing agent foam flowing along the flow duct 22. Instead, a nozzle constitutes a localized obstacle, not present across the entire cross-section of the flow duct, against which the flow of extinguishing agent foam bursts, or impacts. This impact locally disrupts the flow of the extinguishing agent foam. Specifically, this impact separates the flow into several distinct jets, each jet passing between two adjacent branches of the nozzle.

[0097] In lance 18 described previously, the consequences of the impact of the flow on one of the upstream or downstream bursters differ depending on which burster is impacted.

[0098] More specifically, after impacting the upstream burster 32, the flow of extinguishing agent foam does not remain in the form of three distinct jets, in particular because these jets come to strike the nozzle body 48. In other words, the flow is constrained, because it is held in the nozzle body 48. The three jets formed by the upstream burster 32 are therefore caused to strike the nozzle body and to collide with each other, and thus to mix in the second foaming zone Z5, which leads to a mechanical mixing of the flow, promoting its foaming.

[0099] On the contrary, after impacting the downstream nozzle 36, the flow of extinguishing agent foam remains in the form of several distinct jets, in the example three distinct jets, because the downstream nozzle 36 is located near the downstream end of the flow conduit 22. In other words, after impacting the downstream nozzle 36, the flow of extinguishing agent foam continues out of the nozzle 18, and is therefore not constrained by the nozzle body 48.

[0100] The specific combination of the upstream nozzle 32, the foaming screen 34, and the downstream nozzle 36, in that order, is particularly advantageous for obtaining a flow of extinguishing agent foam from the nozzle 18 with optimal density and homogeneity, and a highly optimized jet shape. This flow is thus particularly well-suited for extinguishing Class A and B fires, while also offering good performance in dielectric tests. These advantages stem primarily from the synergy between these three elements, each of which modifies the extinguishing agent foam flow differently to improve its properties.

[0101] Any feature described for an embodiment or variant in the foregoing may be implemented for the other embodiments and variants described above, provided that it is technically feasible.

Claims

1. Lance (18) for fire extinguisher (10), intended for projecting and foaming a fluorine-free extinguishing agent, the lance defining a flow duct (22) for 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 designed to draw air from the outside of the lance into the flow duct, so as to allow the extinguishing agent to be foamed by mixing with the air; - a foaming screen (34) intended to improve the foaming of the extinguishing agent; and - a downstream diffuser (36), designed to divide the flow of extinguishing agent into several separate jets, such that - the downstream diffuser (36) is star-shaped with at least three arms (36A, 36B, 36C), uniformly angularly offset about the main axis (X), and - the lance (18) also comprises an upstream diffuser (32), located between the air inlet opening (30) and the foaming screen (34).

2. Lance (18) according to claim 1, in which the upstream diffuser (32) and the downstream diffuser (36) comprise the same number of arms and in which the arms (36A, 36B, 36C) of the downstream diffuser are angularly offset from the arms (32A, 32B, 32C) of the upstream diffuser, about 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, about the main axis (X), from the arms (32A, 32B, 32C) of the upstream diffuser (32) and from the arms (36A, 36B, 36C) of the downstream diffuser (34).

4. Lance (18) according to any one of the preceding claims, wherein the total cross-sectional area of the injection holes (38) is between 5.5 mm2 and 10 mm2, preferably equal to 8 mm2, the cross-sectional area of each injection hole being measured perpendicular to the main axis (X), and wherein, preferably, the injection nozzle (28) comprises six injection holes (38).

5. Lance (18) according to any one of the preceding claims, in which the injection nozzle (28) comprises, upstream of the injection holes (38): - an external 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 internal restriction (42), arranged in the centre 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 cause the flow of the extinguishing agent to converge towards the injection holes (38), and wherein, preferably, the outer restriction is in the form of a truncated cone and the inner restriction is conical.

6. A lance (18) according to any one of the preceding claims, wherein each arm (36A, 36B, 36C) of the downstream diffuser (36) has a tip-shaped section, a tip of which is directed upstream of the flow duct (22), wherein, preferably, the tip-shaped section of each arm of the downstream diffuser is an isosceles triangle-shaped section, and wherein, preferably, an angle (θ) 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 diffuser (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 one of the preceding claims, wherein a length (L5) between the upstream diffuser (32) and the foaming screen (34) is greater than or equal to four times a length (L6) between the foaming screen and a downstream end of the downstream diffuser (36), the lengths being measured along the main axis (X).

9. Lance (18) according to any one of the preceding claims, wherein, from the injection nozzle (28) to the upstream diffuser (32), the flow duct (22) has a truncated-conical shape converging in the direction of flow of the extinguishing agent, and wherein, from the upstream diffuser (32) to the foaming screen (34), the flow duct has a truncated-conical shape diverging in the direction of flow of the extinguishing agent.

10. Lance (18) according to any one of the preceding claims, wherein the downstream diffuser (36) is star-shaped with three arms, four arms or six arms.

11. Fire extinguisher (10) comprising an extinguisher body (12), a flexible hose (14) and a nozzle (18), the extinguisher body comprising a bottle of extinguishing agent, characterised 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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