FIRE FIGHTING SYSTEM FOR AN EXHAUST DUCT, IN PARTICULAR FOR A COOKING STOVE

Description

[0001] Fire suppression systems are widely used to monitor rooms and buildings, enabling the rapid and targeted application of extinguishing agents to contain and, ideally, extinguish a fire in the event of a blaze. A particular application of such systems is fire suppression via the application of extinguishing agents in exhaust ducts. These can include, for example, exhaust ducts from air conditioning systems, ventilation systems, or exhaust ducts for extracting cooking fumes. Cooking fumes often consist of a mixture of room air, water vapor, and carbon-containing solids and fats carried along by the water vapor.

[0002] For exhaust ducts that only carry air, fire suppression measures are always necessary when the spread of fire through a building needs to be contained, as fire often finds its way through the building via ductwork. With larger duct cross-sections, sealing such ducts using conventional fire protection devices is no longer sufficient. These devices rely on the swelling of intumescent materials, such as expandable graphite, to prevent fire spread by blocking the duct cross-section. While the swelling capacity of these known materials is considerable, it is limited by their design. Revised description pages (fair copy)

[0003] Therefore, for certain cross-sectional diameters in the channels, the use of dispensing devices for extinguishing fluid is advisable, for example in the form of spray mist nozzles.

[0004] In the case of exhaust ducts that carry flammable materials, such as fats, a fire can also develop in the duct itself if deposited fats are ignited.

[0005] US Patent 2013 / 0074823 A1 discloses a cleaning system for cooker exhaust systems, a method for cleaning cooker exhaust air, and a self-cleaning exhaust system. WO 2017 / 032918 A1 discloses a fire suppression system for a ventilation system with an associated method. CN 205245277 U discloses a range hood with an extinguishing device. US Patent 7789165 B1 discloses an industrial fire protection system for oil cookers with an associated method. CN 208145263 U relates to a fire alarm and suppression system for a private kitchen.

[0006] DE 203 00 845 U1 or WO 2018 / 006000 A1 each disclose spray mist nozzles with multiple spray mist outlets aligned at an angle to each other.

[0007] The design of fire suppression systems for exhaust ducts, which consist of a duct comprising an inlet and an outlet separated from the inlet, and define a direction of exhaust airflow from the inlet to the outlet, is complex. It is necessary to reliably and uniformly supply the entire cross-section of the duct, perpendicular to the exhaust direction, with extinguishing fluid, while simultaneously distributing as much extinguishing fluid as possible along the exhaust direction to combat any fires that may already be present there. This requires careful planning of the spacing between any multiple extinguishing agent dispensing devices.Furthermore, the extinguishing agent itself is a limited resource in many applications, particularly on ships, as it is not always possible to use seawater for extinguishing fires. Seawater, due to its salt content, would severely corrode the pipes of a fire suppression system, thus reducing its service life. Additionally, the operating pressure at which the extinguishing agent can be supplied to the extinguishing agent delivery devices is a major factor in the installation costs of the fire suppression system. Higher operating pressure requires greater stability of the installed components and results in higher energy costs for the power supply to the water supply and generators, especially on ships.

[0008] Against this background, there was a need to improve existing fire suppression systems in general, but especially for exhaust ducts assigned to cooking areas.

[0009] The invention was therefore based on the objective of improving a fire-fighting system of the type described above in such a way as to overcome the aforementioned disadvantages as far as possible. In particular, the invention was based on the objective of providing a fire-fighting system for a cooking range exhaust duct that overcomes the aforementioned disadvantages as far as possible.

[0010] The invention solves the underlying problem by installing at least one spray mist nozzle in the fire suppression system, preferably several spray mist nozzles, each having several separate spray mist outlets, wherein the spray mist outlets each have a predetermined K-factor and are aligned at an angle to each other, wherein the spray mist nozzle has a first spray mist outlet that is aligned perpendicularly to the opposite side wall, and two second spray mist outlets that are each aligned at a predetermined angle (β) to the first spray mist outlet.

[0011] Within the scope of the invention, the K-factor is defined as a characteristic value that is determined according to the following equation: K = Q √ p with Q being the volume flow rate in l / min, ρ and p being the static pressure in front of the nozzle in bar.

[0012] The invention is based on the premise that using spray nozzles with multiple spray outlets allows for a significantly wider distribution of the extinguishing agent within the duct compared to nozzles with only a single spray outlet. Furthermore, the spacing between the spray nozzles can be maximized, resulting in reduced installation effort for the fire suppression system. Additionally, the spray outlets allow the spray pattern to be adapted to the specific structural conditions.

[0013] The invention is advantageously further developed in a first aspect by the fire suppression system comprising a hood arranged on the inlet side of the exhaust duct, in particular associated with the cooking area, for receiving cooking fumes from the cooking area, wherein the inlet side of the duct is fluidly connected to the hood, and wherein a spray mist nozzle is installed in the hood, which has several separate spray mist outlets, each having a predetermined K-factor and oriented at an angle to one another. Within the scope of the invention, the term "hood" is generally understood to mean the component that receives the mixture of substances to be conveyed through the exhaust duct, for example, room air or, in particular, cooking fumes. Such a hood can be open to the side and / or downwards. It can be mounted on the ceiling of a room, hang from the ceiling, or be arranged on a side wall of a room.Under the terms of the invention, a hood also includes receiving openings for the mixture to be conveyed, which are not located vertically above the point of origin of the mixture to be conveyed, but on the same level or below, and which first convey the mixture downwards before it enters the extraction channel.

[0014] According to the invention, the hood has two opposing side walls, and the hood spray nozzle is installed on one of the side walls and configured to emit spray mist towards the opposite side wall. The spray mist outlets of the hood spray nozzle are aligned horizontally and / or parallel to the hood's inlet opening in a plane. This applies particularly to configurations in which the hood's inlet opening points upwards or downwards, for example, above or below a cooking surface.

[0015] According to the invention, the spray nozzle is a hood-type spray nozzle with a first spray outlet oriented perpendicularly to the opposite side wall, and two second spray outlets, each oriented at a predetermined angle to the first spray outlet. This ensures that the first spray nozzle is designed to selectively traverse the cross-section of the duct, while the two second spray outlets can be directed towards the third and fourth side walls of the hood in order to cover the entire opening area of ​​the hood with spray mist, and in particular also the corresponding side walls.

[0016] According to the invention, the K-factor of the first spray outlet is higher than the K-factors of the second spray outlets. This represents a particular advantage recognized by the inventors. Due to the higher K-factor of the first spray outlet, it has a greater throw distance than the second spray outlets. The second spray outlets, in turn, have a finer atomization characteristic. Because the spray outlets are aligned at a predetermined angle to each other, the following effect occurs according to the invention: The fine spray from the second spray outlets is partially carried along by the spray from the first spray outlet, so that, due to the differentiation of the K-factors according to the invention, even finer spray is propelled further towards the second side wall than would be the case if all spray outlets had the same K-factors.This results in a higher fire-fighting effect with the same water requirement.

[0017] In a preferred embodiment, the K-factor of the first spray mist outlet of the hood spray nozzle is in a range of 0.6 to 0.9. More preferably, the K-factor of the first spray mist outlet is three to four times higher than the K-factor of the second spray mist outlets of the hood spray nozzle, wherein the K-factor of the second spray mist outlets of the hood spray nozzle is preferably in a range of 0.15 to 0.25.

[0018] The invention has been described above with reference to a first aspect. In a second aspect, which is both a preferred embodiment of the first aspect and an independent aspect, the invention proposes, in a fire-fighting system of the type described above, that one or more duct spray nozzles are installed in the duct, in particular downstream of the hood, wherein the duct spray nozzle each has several separate spray outlets, each having a predetermined K-factor and oriented at an angle to one another.

[0019] The preferred embodiments and advantages of the fire-fighting system described below according to the second aspect are also preferred embodiments and advantages of the fire-fighting system according to the first aspect, just as the advantages and preferred embodiments of the fire-fighting system according to the first aspect are preferred embodiments and advantages for the second aspect.

[0020] According to the invention, the fire suppression system duct has two opposing side walls, and the duct spray nozzle is installed on one of the side walls and configured to emit spray mist towards the opposite side wall. The spray nozzle in the duct is preferably installed in a vertical side wall.

[0021] The spray outlets of the duct spray nozzle are preferably aligned in a plane, preferably parallel to the direction of the duct. In a horizontal duct, the spray outlets are therefore aligned in a horizontal plane. However, if the duct is slightly inclined relative to the horizontal, which is frequently encountered in practice, the spray outlets are preferably aligned in a similarly slightly inclined plane.

[0022] In a preferred embodiment, the alignment of the spray nozzles is carried out as follows: Preferably, the channel has a mounting opening in the side wall in which the spray nozzle is to be installed, and the spray nozzle is mounted in the side wall from the outside through the mounting opening. The channel has a first positioning element on an outer side of the side wall, and the channel spray nozzle has a corresponding second positioning element. The first positioning element is positioned relative to the mounting opening such that, when aligned with each other, the two positioning elements result in correct alignment of the plane of the spray outlets relative to the direction of the channel. The positioning elements can, for example, be optical indicators that are aligned in a straight line with each other or that interlock positively.In the latter case, the spray nozzle can preferably only be mounted on the duct if the positioning elements are correctly aligned. Providing these positioning elements reduces the risk of misalignment of the spray nozzle. Visual inspection of the duct interior becomes unnecessary, significantly optimizing both installation effort and quality.

[0023] According to the invention, the spray nozzle is a duct spray nozzle with a first spray outlet oriented perpendicularly to the opposite side wall and two second spray outlets, each oriented at a predetermined angle to the first spray outlet. One of the second spray outlets is directed against the direction of the exhaust airflow, and the other is directed in the direction of the exhaust airflow. The direction of the exhaust airflow is essentially the direction of the duct. Orienting one of the second spray outlets upstream in the duct and the other downstream results in particularly good spray distribution along the duct direction, while the first spray outlet specifically promotes a spray distribution perpendicular to the direction of the exhaust airflow.

[0024] According to a first alternative of the invention, the K-factor of the first and second spray mist outlets of the duct spray mist nozzle is identical and preferably lies in a range of 0.2 to 0.5.

[0025] According to a second alternative of the invention, the K-factor of the first spray mist outlet of the duct spray mist nozzle is higher than the K-factors of the second spray mist outlets of the duct spray mist nozzle, and the sum of the K-factors of the first and second spray mist outlets is in a range of 0.9 to 1.5.

[0026] The advantage of a first spray mist outlet with a higher K-factor is, as described above for the first aspect, a greater throw distance of the spray mist from the first spray mist outlet, which carries along more finely atomized extinguishing agent from the second spray mist outlets in a transverse direction to the channel.

[0027] In a third aspect, the invention relates to a particularly preferred parameterization of the fire suppression system. The advantages and preferred embodiments of the first and second aspects are simultaneously advantages and preferred embodiments of the third aspect; therefore, to avoid repetition, reference is made to the above explanations. The following preferred embodiments of the third aspect are also preferred embodiments of the first and second aspects.

[0028] Preferably the hood has an inlet cross-section in a range of 3 m² to 5 m², and a maximum distance between horizontally opposing side walls in a range of 2 m to 4 m.

[0029] Furthermore, the channel preferably has a flow cross-section in a range of 1 m² to 2 m², and a maximum distance between horizontally opposing side walls in a range of 1 m to 2 m.

[0030] Preferably, the hood spray nozzle and a duct spray nozzle installed adjacent to it have a distance in the direction of the exhaust air flow of a range of 1 m to 3 m.

[0031] Preferably, several duct spray nozzles are installed in the duct and are spaced 9 m to 11 m apart in the direction of the exhaust air flow.

[0032] In a further preferred embodiment, the spray nozzles are fluidly connected to a fire extinguishing fluid supply, wherein the spray nozzles and the fire extinguishing fluid supply are designed for an operating pressure at the spray nozzles in a range of 70 bar or less, preferably in a range of 50 bar to 65 bar.

[0033] Preferably, the channel has a bend, with a channel spray nozzle installed downstream and / or upstream of the bend at a distance of 6 m or less. A bend is understood to be a component that causes a change in the direction of the channel, for example about a vertical or horizontal axis, preferably by 45° or more, and particularly preferably by 90° or more.

[0034] In a particularly preferred embodiment, the aforementioned parameters of the third aspect are jointly realized, achieving a superior efficiency in the use of the extinguishing agent compared to previous systems, with low installation effort and yet undiminished high fire-fighting performance.

[0035] In further preferred embodiments, the spray nozzle(s) are partially or completely made of stainless steel. The use of stainless steel as the nozzle material significantly increases the permissible operating temperature range compared to copper nozzles or copper components known from the prior art. This provides a much higher temperature reserve.

[0036] In another preferred embodiment, the spray mist nozzles are designed as open extinguishing nozzles.

[0037] In a further preferred embodiment, one or more fire parameter sensors are installed on the hood and / or on the duct, wherein the fire suppression system has a triggering device that is directly or indirectly connected to the fire parameter sensors and is configured to start the supply of extinguishing agent to the spray nozzles as soon as the fire parameter sensors detect that a predetermined fire parameter threshold has been reached or exceeded, or that a fire parameter is present. According to the invention, fire parameters include, for example, temperatures, smoke aerosols, electromagnetic radiation from flames, sparks or embers, or combustion gases.

[0038] The invention is described in more detail below with reference to a preferred embodiment and the accompanying figures. These figures show: Figure 1 shows a schematic spatial view of a fire suppression system according to a preferred embodiment, Figures 2a to c show schematic detail views of the fire suppression system according to Figure 1 Figures 3a to g show further schematic detail views of the fire suppression system according to the Figures 1 to 2c Figures 4a-4c show various schematic representations of a spray nozzle according to a preferred embodiment; Figure 5 shows a schematic cross-sectional view through a nozzle insert for the spray nozzle according to Figures 4a-4c Figures 6a-6c show various schematic representations of a basic body of the nozzle insert according to Figure 5 , and Figures 7a-7 show various schematic representations of a swirl body for nozzle use according to the Figures 4a-6c .

[0039] In Figure 1A fire suppression system 100 is shown. The fire suppression system 100 has a hood 3 which is designed to receive mixtures of substances to be conveyed, for example, cooking fumes from a cooking area located under the hood.

[0040] A bend 4 is connected to the hood 3, which deflects the incoming mixture flow by approximately 90° around a horizontal axis and then transfers it into a channel 5, also referred to as an exhaust channel. The channel 5 extends from its hood-side inlet 7 to an outlet 9, where one or more flow generators for forced exhaust can optionally be arranged.

[0041] Channel 5 defines a flow direction A of the exhaust air, which is essentially the same as the orientation of channel 5. The hood 3 has a hood spray nozzle 11. At least one channel spray nozzle 13 is arranged in channel 5 at a distance from the hood spray nozzle 11. In the present embodiment, there are three channel spray nozzles 13.

[0042] Channel 5 has a bend 6 in which the channel's path is deflected by 90° around a vertical axis. The distance from a first channel spray nozzle 13 to the bend 6 is between 4 m and 6 m. A second channel spray nozzle 13 is located on the downstream side of the bend 6, at a distance of between 4 m and 6 m from the bend.

[0043] Further downstream, a third channel spray mist nozzle is arranged at a distance of 9 m to 12 m from the second channel spray mist nozzle 13.

[0044] The channel spray nozzles 13 are preferably mounted in a first side wall 21 of the channel 5 and configured to emit a spray mist towards the opposite second side wall 23 of the channel 5. Details regarding the alignment of the spray nozzles are shown in the following figures.

[0045] As can be seen from the overall view of the Figures 2a to c The hood spray nozzle 11 has several spray mist outlets located in a common plane E2. Plane E2 is parallel to plane E1, which defines the inlet cross-section to the hood 3. The hood spray nozzle 11 is positioned in a first side wall 17 of the hood 3 and is configured to emit spray mist through the spray mist outlets towards the opposite side wall 19, cf. Figure 3a .

[0046] Within channel 5 are the channel spray nozzles 13, one of which is in the Figures 2aand c shown, arranged such that the spray mist outlets are each located in a common plane E 3 parallel to the flow direction A of the exhaust air and thus to the direction of the duct 5. In the case of a horizontal duct 5, the plane E 3 in which the spray mist outlets of the duct spray mist nozzle 13 are located would also be horizontal.

[0047] Of the spray mist outlets of the duct spray nozzle 13, a first spray mist outlet is oriented transversely to the flow direction A of the exhaust air, while a second spray mist outlet is oriented against the flow direction, and a further second spray mist outlet is angled in the flow direction relative to the first spray mist outlet. This is described in more detail in the Figures 4a and explained below for the hood spray nozzle 11 and the duct spray nozzles 13.

[0048] In Figure 3a , which shows a top view of the fire suppression system according to Figure 1The dimensions of hood 3 relative to duct 5 are shown. Hood 3 has a cross-section B1 - B2 of approximately 3m² to 5m².

[0049] From the hood 3, it transitions into the channel 5, which has a reduced cross-section, a width B 3 and a height H 1, preferably in the range of 1m 2< to 2m 2< .

[0050] As in Figure 3b As schematically indicated, channel 5 is at least partially inclined at an angle α relative to the horizontal, so that the flow direction A of the exhaust air is not exactly horizontal. The orientation of the spray nozzles preferably takes this into account.

[0051] Figures 3c to 3gFigure 1 illustrates the alignment of the hood spray nozzle 11 with the spray outlets in plane E 2, in a direction essentially towards the opposite second side wall 19. In the hood, a V-shaped separator is arranged, preferably in the direction of the inlet cross-section in plane E 1, as seen from the hood spray nozzle 11.

[0052] After the Figures 1 to 3g In principle, the structure of the fire suppression system and the positioning of the spray mist nozzles 11, 13 were shown; in the following figures, an exemplary preferred structure of the spray mist nozzles 11, 13 themselves is shown.

[0053] In Figure 4a An exemplary spray mist nozzle is shown, which can be used as a hood spray mist nozzle 11 or as a duct spray mist nozzle 13. The spray mist nozzle 11, 13 has a housing 27 into which a first nozzle insert 29a and two second nozzle inserts 29b are inserted.

[0054] In Figure 4bThe spray nozzle 11, 13 is shown in a side view. On the inlet side, the spray nozzle 11, 13 has a sieve body 31. The housing 27 has a thread 33 for installing the spray nozzle. A sealing ring 35 is provided for sealing the housing 27 against the mounting body. The housing has a convexly curved, preferably partially spherical, surface section 37, to which a frustoconical surface section 39 adjoins. Towards the inlet side, the housing 27 has a cylindrical surface section 41. The nozzle inserts are essentially flush with the surface of the housing 27.

[0055] In Figure 4c Figure 1 shows a cross-sectional view through the housing 27 of the spray nozzle 11, 13. The housing 27 has a fire extinguishing fluid inlet 45. On the inside of the fire extinguishing fluid inlet 45 is an internal thread 43 for mounting the filter body 31 (see Figure 2). Figure 1 ) provided.

[0056] The housing has several recesses 47 for receiving a nozzle insert 29a, b each. The recesses 47 each have an internal thread for screwing in the nozzle inserts 29a, b. Furthermore, the nozzle inserts 29a, b are fluid-conductingly connected to the extinguishing fluid inlet 45.

[0057] One of the recesses 47 is aligned coaxially with a mounting direction M defined by the extinguishing fluid insert 45, such that the longitudinal axis L of the nozzle insert 29a to be inserted into the recess 47 is also aligned coaxially with the mounting direction. The remaining recesses 47 are aligned at an angle β to the mounting direction M. The angle β is preferably in a range between 50° and 70°, particularly preferably at 60° or 65°.

[0058] After the Figures 4a-4c The focus on the case shows Figure 5Now, the nozzle insert 29a, b, which is to be inserted into the recesses 47. The nozzle insert 29a, b has a base body 49. A swirl body 51 is inserted into the base body 49 and aligned coaxially with the longitudinal axis L. The swirl body 51 is fixed in the base body 49 by means of a screwed-in retaining ring 53.

[0059] The base body 49 has an external thread 55 for screwing into the respective recess 47. To facilitate screwing in the nozzle insert 29a, b, recesses 57 for attaching a screwing tool are provided on the outlet-side end face of the nozzle insert 29a, b.

[0060] The base body 49 has a spray mist outlet 24 / 25 through which the extinguishing fluid entering via the extinguishing fluid inlet 23 exits the spray mist nozzle 1 in the form of a spray mist after passing through the nozzle insert 29a, b. The spray mist is generated by deflecting a first portion T 1 of the entering extinguishing fluid outwards in the direction of arrows T 1 by the swirl body 51 into its circumferential region and towards a wall of the base body 49, in order to then be directed into a vortex upon approaching the spray mist outlet 24 / 25. A second partial flow T 2 passes through the swirl body 51 in its center through a through-opening (see figure). Figures 7a-e ).

[0061] The following refers to the Figures 6a-6cThe main body 49 is discussed further. The main body 49 of the nozzle insert 29a, b has an inlet-side end face 61 and an outlet-side end face 65. A through-opening 63 extends between these two end faces 61, 65, into which the swirl body 51 is received (see figure). Figure 2 ) and which leads into the spray mist outlet 24 / 25. The spray mist outlet 24 / 25 is described in detail in Figure 6c shown.

[0062] Upstream of the spray outlet 24 / 25, the base body 49 has a seat 67 against which the swirl body 51 is supported. The seat 67 transitions into the spray outlet 24 / 25 at a single point. The cross-section at which the seat 67 transitions into the cross-section of the spray outlet 24 / 25 is the so-called inflow cross-section 69. Within the inflow cross-section 69, the spray outlet 24 / 25 has a diameter d. The transition from the seat 67 to the spray outlet 24 / 25 is preferably continuous.

[0063] At its narrowest point, the spray mist outlet 24 / 25 has a minimum flow cross-section 71. The minimum flow cross-section 71 is offset inwards at a depth T from the outlet-side frontal surface 65.

[0064] Downstream of the minimum flow cross-section 71, the spray mist outlet 24 / 25 is widened along a convex curvature and has a diameter d at an outlet cross-section 73 that is larger than the diameter at the minimum flow cross-section 71. The diameter at the minimum flow cross-section 71 is denoted by d min.

[0065] Preferably, the transition from the inflow cross-section 69 to the minimum flow cross-section 71 occurs along a convexly curved surface with a radius of curvature R. More preferably, the transition from the minimum flow cross-section 71 to the outlet cross-section 73 also occurs along a convexly curved surface, in the present embodiment also with the radius of curvature R. Particularly preferably, the convexly curved surface from the inflow cross-section 69 to the outlet cross-section 69 is continuous, i.e., free of kinks. Particularly preferably, the curvature profile is continuous and constant with the same radius of curvature R. The rounded contour of the spray mist outlet 24 / 25, resulting from the convex curvature, produces an unexpectedly significant stabilization of the K-factor of the nozzle insert 29a, b.

[0066] In the Figures 7a-7eThe swirl body 51 for the nozzle insert 29a, b of the present embodiment is described in more detail below. Figure 7a A side view of the swirl body 51 with a partially exposed cross-section is shown first. The swirl body 51 is exposed to a flow of extinguishing fluid on a first, inlet-side end face 75. A first portion T 1 is diverted to the outer circumference of the swirl body 51 by several radially extending grooves 79. This is also shown in Figure 7b shown. A second part T 2 flows without deflection to the outer circumference through a through-opening 81 to a second end face 83 of the swirl body 51. The first partial flow T 1 is, as shown in particular in Figure 7cAs can be clearly seen, the air is conveyed back towards the spray outlet 24 / 25 through several vortex channels 85 arranged eccentrically and radially parallel to the longitudinal axis L. The off-center arrangement of the vortex channels 85 generates a vortex flow in the volume between the swirl body 51 and the base body 49 upstream of the spray outlet. In this free space, the two partial flows T1 and T2 are recombined and expelled together through the spray outlet 24 / 25.

[0067] The vortex channels 85 are preferably all offset by the same offset V to a respective radial.

[0068] As in Figure 7d As can be clearly seen, the swirl channels 85 are inclined at an angle γ relative to the outlet-side, second end face 83 of the swirl body 51. Preferably, the swirl channels 85 or the groove bases of the swirl channels 85 are aligned parallel to a seating surface 77 of the swirl body 51.

[0069] Furthermore, how Figure 7e The preceding figures show that the swirl channels 85 with a width B are provided in the swirl body 51 and are additionally pivoted by an angle δ relative to the longitudinal axis L. The preceding figures illustrate a high-pressure spray nozzle 1 with a total of three nozzle inserts 29a, b, based on the above embodiment. The invention also encompasses spray nozzles having a different number of nozzle inserts, for example, five, seven, or more nozzle inserts, in which either each nozzle insert is aligned coaxially to the mounting direction M, or in which all nozzle inserts are aligned at an angle β to the mounting direction M, or in which one or more recesses 47 are not provided with a nozzle insert 29a, b or are closed with a blanking plug or similar sealing element. Reference symbol list:

[0070] 100 Firefighting system 3 Hood 4 Bend 5 Channel 6 Bend 7 Inlet side 9 Outlet side 11 Hood spray mist nozzle 13 Channel spray mist nozzle 14 Temperature sensor 15 Separator 17 Side wall, hood 19 Side wall, hood 21 Side wall, channel 23 Side wall, channel 24 First spray mist outlet 25 Second spray mist outlet E1, E2, E3 Plane A Flow direction Exhaust air B Width, vortex channel d at Inlet cross-section d min Minimum flow cross-section d out Outlet cross-section L Longitudinal direction M Mounting direction, spray mist nozzle T1, T2 Partial flow, extinguishing fluid T Depth, minimum flow cross-section V Offset, vortex channel α Angle of inclination, channel β Angle, spray mist outlet g-angle, spinal canal; δ-angle, spinal canal 27 Housing 29a,b Nozzle insert 31 Filter body 33 Thread 35 Sealing ring 37 Partially spherical surface section 39 Fructed conical surface section 41 Cylindrical section 43 Internal thread 45 Extinguishing fluid inlet 47 Recess for nozzle insert 48 Internal thread, nozzle insert 49 Base body 51 Swirl body 53 Retaining ring 55 External thread 57 Recess 59 Internal thread 61 Inlet-side end face, base body 63 Through-opening 65 Outlet-side end face, base body 67 Seat surface, base body 69 Inflow cross-section 71 Minimum flow cross-section 73 Outlet cross-section 75 First end face, swirl body 77 Seat surface, swirl body 79 Groove 81 Through-opening, swirl body 83 Second end face, swirl body 85 Vortex canal

Claims

1. A firefighting system (100) for an extractor duct (5), in particular of a cooking area, the firefighting system (100) having a duct (5) which has two opposite side walls (21, 23) and an inlet side (7) and an outlet side (9), which is spaced apart from the inlet side (7), and defines a direction (A) of the extracted air flow from the inlet side (7) to the outlet side (9), and a hood (3), which has two opposite side walls (17, 19) and is arranged on the inlet side of the extractor duct, in particular assigned to the cooking area for receiving cooking fumes from the cooking area, wherein the inlet side (7) of the duct (5) is in fluid communication with the hood (3), wherein at least one spray mist nozzle is installed in the firefighting system (100), characterized in that - said at least one spray mist nozzle (11, 13) is installed on a side wall (17, 19; 21, 23) of the hood (3) - as hood spray mist nozzle (11) - or of the duct (5) - as a duct spray mist nozzle (13) -, - the spray mist nozzle (11, 13) respectively having a plurality of separate spray mist outlets (24, 25), wherein the spray mist outlets (24, 25) each have a predetermined K-factor and are oriented at an angle (β) to one another, - wherein the spray mist nozzle (11, 13) has a first spray mist outlet (24), which is oriented perpendicularly to the opposite side wall (19), and two second spray mist outlets (25), which are each oriented at a predetermined angle (β) to the first spray mist outlet (24), - wherein the spray mist outlets (24, 25) of the hood spray mist nozzle (11) are oriented in a plane (E2) horizontally und / or parallel to the inlet opening of the hood (3), and the spray mist outlets (24, 25) of the duct spray mist nozzle (13) are oriented in a plane (E3), preferably parallel to the direction (A) of the duct, wherein one of the second spray mist outlets (25) is directed counter to the direction (A) of the extracted air flow and the other of the second spray mist outlets (25) is directed in the direction (A) of the extracted air flow, - wherein the K-factor of the first spray mist outlet (24) of the hood spray mist nozzle (11) is higher than the K-factors of the second spray mist outlets (25), wherein the sum of the K-factors lies in a range from 0,9 to 1,5, - wherein the K-factor of the first and second spray mist outlets (24, 25) of the duct spray mist nozzle (13) is respectively identical and lies in a range from 0,2 to 0,5; or - wherein the K-factor of the first spray mist outlet (24) of the duct spray mist nozzle (13) is higher than the K-factors of the second spray mist outlets (25) of the duct spray mist nozzle (13), wherein the sum of the K-factors lies in a range from 0,9 to 1,5.

2. The firefighting system (100) as claimed in claim 1, wherein the K-factor of the first spray mist outlet (24) of the hood spray mist nozzle (11) lies in a range from 0.6 to 0.9, and / or wherein the K-factor of the first spray mist outlet (24) is three to four times as high as the K-factor of the second spray mist outlets (25) of the hood spray mist nozzle (11), and wherein preferably the K-factor of the second spray mist outlets (25) of the hood spray mist nozzle (11) lies in a range from 0.15 to 0.25.

3. The firefighting system (100) as claimed in one of the preceding claims, wherein one or more duct spray mist nozzles (13) are installed in the duct (5).

4. The firefighting system (100) as claimed in claim 3, wherein the spray mist nozzle is mounted on the duct from the outside through a mounting opening in the side wall, and the duct has a first positioning element on an outer side of the side wall, on which the duct spray mist nozzle is mounted, and wherein the duct spray mist nozzle has a corresponding second positioning element, wherein the first positioning element is positioned in such a way relative to the mounting opening that the two positioning elements, when they are aligned with one another, bring about a correct orientation of the plane (E3) of the spray mist outlets relative to the direction (A) of the duct.

5. The firefighting system (100) as claimed in one of the preceding claims, wherein the hood (3) has an inlet cross-sectional area in a range from 3 m2 to 5 m2 and a maximum spacing of horizontally opposite side walls (17, 19) in a range from 2 m to 4 m.

6. The firefighting system (100) as claimed in one of the preceding claims, wherein the duct (5) has a flow area in a range from 1 m2 to 2 m2 and has a maximum spacing of horizontally opposite side walls (21, 23) in a range from 1 m to 2 m.

7. The firefighting system (100) as claimed in one of the preceding claims, wherein the hood spray mist nozzle (11) and a duct spray mist nozzle (13) installed adjacent thereto have a spacing in a range from 1 m to 3 m in the direction (A) of the extracted air flow.

8. The firefighting system (100) as claimed in one of the preceding claims, wherein a plurality of duct spray mist nozzles (13) are installed in the duct (5) and are mutually spaced in a range from 9 m to 11 m from one another in the direction (A) of the extracted air flow.

9. The firefighting system (100) as claimed in one of the preceding claims, wherein the spray mist nozzles (11, 13) are fluidically connected to an extinguishing fluid supply, wherein the spray mist nozzles (11, 13) and the extinguishing fluid supply are designed for an operating pressure at the spray mist nozzles (11, 13) in a range of 70 bar or less, preferably in a range from 50 bar to 65 bar.

10. The firefighting system (100) as claimed in one of the preceding claims, wherein the duct (5) has an elbow (4, 6), and wherein a duct spray mist nozzle is installed downstream and / or upstream of the elbow (4, 6) and has a spacing in a range of 6 m or less from the elbow (4, 6).

11. The firefighting system (100) as claimed in one of the preceding claims, wherein the spray mist nozzle or spray mist nozzles (11, 13) is / are formed partially or entirely from stainless steel.

12. The firefighting system (100) as claimed in one of the preceding claims, wherein the spray mist nozzles (11, 13) are in the form of open extinguishing nozzles.

13. The firefighting system (100) as claimed in one of the preceding claims, wherein one or more fire characteristic sensors (14) are installed at the hood (3) and / or at the duct (5), and wherein the firefighting system (100) has a triggering device that is connected to the fire characteristic sensors (14) indirectly or directly in a signal-conducting manner and is designed to start the feed of extinguishing agent to the spray mist nozzles (11, 13) as soon as the fire characteristic sensors (14) sense the reaching or exceeding of a predetermined fire characteristic threshold or the existence of a fire characteristic.