Floating additive dose for a water extinguisher

Abstract

The invention relates to a floating dose of additive (1) for a water fire extinguisher, comprising a longitudinal container (2) having an open end (3) provided with an external edge (4), and an external sealing cap for the open end (3) integral with the external edge (4), which floating dose (1) comprises an internal sealing cap (8) which is disposed in the container (2) and which is integral with an internal circumferential shoulder (9) of said container (2).

Description

TECHNICAL FIELD

[0001] The invention falls within the field of fire safety, and more particularly within the field of water fire extinguishers equipped with floating doses of additives. PRIOR ART AND DISADVANTAGES OF PRIOR ART

[0002] As is known, water fire extinguishers include a water tank, a compressed gas cartridge housed in the tank, a spray nozzle, and a control handle that not only operates the compressed gas cartridge to pressurize the extinguisher's water tank - for example, 5 to 6 bars of pressure, and usually up to 15 or 16 bars - but also controls the opening of the spray nozzle.

[0003] To improve the extinguishing properties of water, it is known to add a surfactant-type additive to the water in the tank. This additive allows foam to form when the water is sprayed, increasing the surface area in contact with the burning elements. Examples of such additives include fluorocarbons, which are known to form a film that floats on the surface of the water.

[0004] These additives, however, have the disadvantage of being polluting and make recycling the fire extinguisher more difficult once they are mixed with water. Furthermore, these additives are corrosive, and their direct contact with water during the extinguisher's storage phase can cause deterioration of the extinguisher's tank walls.

[0005] To overcome this drawback, publication EP0461020 proposes introducing a floating dose of additive into the tank. This dose consists of an additive reservoir with an open end sealed by a watertight cap. Thus, during the extinguisher's storage phase—that is, before the compressed gas is released into the water tank prior to use—the additive stored in the floating dose does not come into contact with the water or the walls of the extinguisher tank. When the extinguisher tank is pressurized, the resulting pressure differential causes the cap to rupture, thereby mixing the additive from the floating dose with the water in the tank.

[0006] Also known from publication EP2666519 is a cartridge for a fire extinguisher comprising several reservoirs, each containing an additive, at least two of these reservoirs being separated by a common side wall. Each reservoir further comprises a frangible, airtight cap for closing said reservoir containing the additive.

[0007] Despite their effectiveness, frangible seals are subject to the corrosive effect of the additive and can deteriorate over time, losing their sealing properties and potentially causing the additive to mix unexpectedly with the water in the extinguisher's reservoir. OBJECTIVE OF THE INVENTION

[0008] The invention therefore aims to provide a floating dose of water fire extinguisher additive that is more resistant to corrosion. DESCRIPTION OF THE INVENTION

[0009] To this end, the invention relates to a floating dose of additive for a water extinguisher comprising a water reservoir and means for pressurizing said water reservoir, the floating dose comprising a longitudinal container having an open end provided with a circumferential outer rim, and an outer sealing cap that is watertight and frangible for the open end attached to the circumferential outer rim, which floating dose further comprises an inner sealing cap that is disposed in the container and attached to an internal circumferential shoulder formed in the wall of said container.

[0010] Thanks to its two sealing caps, the floating dose is thus more resistant to corrosion.

[0011] The floating dose may also include the following optional characteristics, considered individually or in all possible technical combinations: The outer seal, under differential pressure caused by pressurizing the extinguisher tank, forms a concavity in the container which tears when the longitudinal distance between the outer circumferential edge and the bottom of the concavity reaches a determined rupture depth, and in that the minimum distance separating the outer circumferential edge from the inner circumferential shoulder is greater than or equal to the rupture depth of the outer seal.Thus, since the minimum distance between the outer circumferential edge and the inner circumferential shoulder is greater than or equal to the rupture depth of the outer seal, the latter can tear without being hindered by the inner seal. The open end of the container has a circular cross-section with radius r, in that the concavity is shaped like a spherical cap with radius r identical to that of the open end of the container, curvature R, and height h = R + / - (R² < -r² < )½, and the rupture depth is correlated to the radius r of the open end of the container. Therefore, during the manufacture of the floating dose container, the distance between the outer circumferential edge and the inner shoulder can be adjusted according to the radius of the outer opening.The ratio between the radius r of the open end of the container and the distance d between the outer edge and the inner shoulder of the container is less than or equal to 10, preferably less than or equal to 5, and preferably approximately 4.5. The distance d between the outer edge and the inner shoulder of the container is greater than or equal to 4.5 mm. The inner and outer seals are heat-sealed against the circumferential inner shoulder and outer edge, respectively. The floating dose includes a handling keel at one opposite end of the container. Thus, the end of the container sealed by the seals remains underwater in the extinguisher tank. The additive occupies no more than 90% of the total volume of the container.The additive thus occupies a fraction of the container's volume, the remainder of the container's volume being occupied by a compressible gas, which allows the seals to rupture when subjected to differential pressure.

[0012] The invention also relates to a water fire extinguisher comprising a water reservoir and means for pressurizing said reservoir, which fire extinguisher further comprises a floating dose as described above housed in the reservoir, the external cap sealing the open end of the container of said floating dose being immersed in the water of the reservoir.

[0013] The fire extinguisher may also include the following optional features, considered individually or in all possible technical combinations: The differential pressure between the reservoir and the floating dose container after pressurization of said reservoir is at least equal to 4 bars. PRESENTATION OF THE FIGURES

[0014] Other features and advantages of the invention will become clear from the description given below, which is by way of example and not limitation, with reference to the attached figures, among which: [ Fig. 1 ] There figure 1 represents a perspective view of the container for the floating dose of additive. Fig. 2 ] There figure 2 represents a cross-sectional view of the floating dose before it is placed under differential pressure in the extinguisher. Fig. 3 ] There figure 3 represents a cross-sectional view of the floating dose after it has been placed under differential pressure in the extinguisher and before the outer seal ruptures. Fig. 4 ] There figure 4 represents a cross-sectional view of the floating dose after it has been placed under differential pressure in the extinguisher and at the moment the outer seal ruptures. Fig. 5 ] There figure 5 represents a detail of an end portion of the floating dose of the figure 2 . [ Fig. 6 ] There figure 6 represents a detail of an end portion of the floating dose of the figure 3 . [ Fig. 7 ] There figure 7 represents a detail of an end portion of the floating dose of the figure 4 . [ Fig. 8 ] There figure 8 represents a detail of a portion of the end of the floating dose after the rupture of the two lids. DETAILED DESCRIPTION OF THE INVENTION

[0015] It is first clarified that in the figures, the same references designate the same elements regardless of the figure in which they appear and regardless of the form in which those elements are represented. Similarly, if elements are not specifically referenced in one of the figures, their references can easily be found by referring to another figure.

[0016] It is also specified that the figures essentially represent one embodiment of the object of the invention, but that there may be other embodiments which meet the definition of the invention.

[0017] The invention relates to a floating dose of additive 1 for a water fire extinguisher, such additive 11 conventionally comprising fluorocarbons. Such a fire extinguisher conventionally comprises a tubular-shaped tank with dome-shaped ends. One end includes an opening allowing the extinguisher tank to be filled with water, as well as the floating dose of additive 1 to be inserted.

[0018] The reservoir opening is closed by a head to which a pressurized gas cartridge housed within the reservoir is attached, and a dip tube extending the full height of the reservoir. The dip tube passes through the extinguisher head and terminates in a liquid spray nozzle.

[0019] The extinguisher head also includes a means of releasing the gas from the cartridge into the reservoir, typically a striker operated by a manual lever to pierce the gas cartridge. Once the gas is released into the reservoir, the internal pressure rises from atmospheric pressure to a pressure exceeding 4 bar, that is, at least 5 to 6 bar and preferably around 15 or 16 bar.

[0020] With reference to figures 1, 2 And 5The floating dose 1 housed in the extinguisher reservoir comprises a longitudinal container 2 extending along an axis X and made of a high-density polyethylene polymer material. This container 2 comprises a cylindrical side wall 13, a bottom wall 14 integral with the side wall, and an open end 3 opposite the open end, with a circular cross-section of radius r. The floating dose 1 further comprises a longitudinal handling keel 10 extending from the bottom wall of the container 2, opposite the open end.

[0021] Container 2 is filled with additive 11, and its open end 3 is hermetically sealed by sealing means 5, 8 to prevent any contact between the additive 11 in the floating dose 1 and the water in the extinguisher reservoir. The volume of additive 11 corresponds to a fraction of the total volume of container 2, typically and without limitation between 75% and 85% of the total volume of container 2, preferably around 80% of the total volume of container 2. This volume fraction of the additive may vary depending on the type of container for the floating dose, the essential point being that a fraction of the container's volume remains filled with compressible gas.

[0022] The open end 3 of the floating dose container 2 includes a circumferential outer edge 4 in the shape of a collar. Furthermore, the container 2 includes a circumferential inner shoulder 9 formed in the side wall 14 of the container 2. Thus, the inner radius of the container 2 between the bottom 14 of said container 2 and the inner shoulder 9 is less than the radius r of the open end 3.

[0023] The surface of the inner shoulder 9 and the surface of the outer rim 4 are parallel to each other and perpendicular to the longitudinal axis X of the container 2. The circumferential outer rim 4 is further located at a distance d from the inner shoulder 9.

[0024] According to the invention and with reference to figures 2 And 5The floating dose 1 includes an inner leak-proof lid 8 housed in the container 2 and heat-sealed against the circumferential inner shoulder 9, these two lids 5, 8 forming the means for sealing the open end 3 of the container 2. The floating dose 1 further includes an outer leak-proof lid 5 heat-sealed against the circumferential outer edge 4. The open end 3 of the container 2 is thus hermetically sealed.

[0025] During the assembly of the fire extinguisher, to insert the floating dose 1 into the extinguisher tank, the operator manipulates the dose 1 by the keel 10 so that, once inside the extinguisher tank, the opposite end 3 of the container 2 is submerged in the water within the tank. Furthermore, the keel 10 increases the overall length of the container 2, which prevents the floating dose 1 from inverting within the extinguisher tank: the open end 3, hermetically sealed by the internal 8 and external 5 caps, remains below the free surface of the water in the extinguisher tank.

[0026] The lids 5 and 8 are made – for example, but not limited to – of composite material, comprising a first coating layer of polymer material, for example with a surface density of approximately 40 g / m², an intermediate metallic layer – typically an aluminum strip with a thickness of approximately 60 microns – and optionally an external lacquer to protect the metallic layer with a surface density of approximately 1.5 g / m². The invention is obviously not limited to these materials, nor to these values ​​of surface density and thickness.

[0027] The coating layer is adapted to be heat-sealed to the container 2 of the floating dose 1, either to the outer edge 4 if it is the outer lid 5, or to the inner shoulder 9 if it is the inner lid 8.

[0028] The metallic layer of the outer lid 5 is therefore intended to be in contact with the water in the extinguisher reservoir, while the coating layer of the inner lid 8 is intended to come into contact with the additive 11 contained in the container 2 of the floating dose 1.

[0029] The two inner seals 8 and outer seal 5 are also frangible and are designed to tear open when the extinguisher tank is pressurized. In particular, each of the seals 5 and 8 is designed to tear open as soon as the differential pressure (i.e., the pressure difference between the inside of the floating dose container 1 (container 2) and the inside of the extinguisher tank) exceeds a predetermined value, typically 4 bar.

[0030] Under the influence of this differential pressure and with reference to figures 3 And 6, the internal 8 and external 5 lids each deform initially into a concavity directed towards the inside of the container 2. In particular, the concavity 6 of the external lid 5 takes the form of a spherical cap of radius r (identical to the radius of the external opening 3 of the container 2), of radius of curvature R, and of height h. The height h is the longitudinal distance between the external circumferential edge 4 of the container 2 and the bottom 7 of the concavity 6. This height h can be expressed according to the formula h = R + / - (R 2< - r 2< ) 1 / 2< .

[0031] With reference to figures 4 And 7 When the height of the concavity 6 of the outer lid 5 reaches a threshold value called the rupture depth hr, the outer lid 5 tears. The inner lid 8 is then subjected to the differential pressure and tears in turn.

[0032] To allow optimal tearing of the outer operculum 5, and so that the tearing of this outer operculum 5 is not hindered by the inner operculum 8, the distance d between the outer circumferential edge 4 and the inner circumferential shoulder 9 is greater than or equal to the rupture depth hr. Now, the height of the concavity 6 of the deformed outer operculum 5 being expressed according to the formula h = R + / - (R 2< - r 2< ) 1 / 2< , the tearing depth is expressed according to the formula hr = R r + / - (Rr 2< - r 2< ) 1 / 2< where R r represents the radius of the spherical cap of height hr . The rupture depth hr is therefore directly correlated to the radius r of the external opening 3 of the container 2, and the distance d separating the external edge 4 from the internal shoulder 9 of the container 2 therefore also depends on the radius r of the external opening 3 of the container 2.

[0033] Typically, to allow optimal tearing of the outer operculum 5, the ratio between the radius r of the open end 3 and the distance d separating the outer edge 4 from the inner shoulder 9 is less than or equal to 10, preferably less than or equal to 5 and again preferably in the order of 4.5.

[0034] Thus, and by way of non-limiting example, for a floating dose 1 whose total length is on the order of 19 cm and whose radius r of the open end is on the order of 45 mm, the distance d separating the outer edge 4 from the inner shoulder 9 is preferably on the order of 10 mm, and greater than 4.5 mm.

[0035] With reference to figures 2 to 7 , and more specifically with reference to figures 5 to 7 , a process for mixing the additive 11 contained in container 2 of the floating dose 1 housed in the extinguisher reservoir with the water from said reservoir will now be described.

[0036] THE figures 2 And5 represent the floating dose 1 when the extinguisher is in storage condition, i.e. the gas cartridge has not released the gas into the reservoir and the pressure in the reservoir remains identical to the pressure in container 2 of the floating dose 1. The two inner 8 and outer 5 seals are therefore in a state of equilibrium, substantially flat and parallel to each other, and hermetically sealing the open end 3 of container 2.

[0037] THE figures 3 And 6 represent the floating dose 1 after the extinguisher tank has been pressurized, but before the inner seal 8 and outer seal 5 have been torn open. Seals 5, 8 are therefore shown here in a non-equilibrium state.

[0038] Pressurizing the extinguisher tank creates a pressure differential between the tank and the floating dose container 1 (container 2). This causes the seals 5 and 8, and in particular the outer seal 5, to deform, forming a spherical concavity 6. For the inner seal 8 and outer seal 5 to deform and eventually rupture, the additive 11 must occupy only a fraction of the volume of container 2, typically around 80%, the remaining volume being filled with gas, which is compressible, unlike the liquid additive 11.

[0039] THE figures 4 And 7represent the floating dose 1 as soon as the apex 7 of the concavity 6 formed by the deformation of the outer seal 5 reaches the rupture depth hr and tears. As described above, to allow optimal tearing of the outer seal 5 without being hindered by the inner seal 8, the rupture depth hr of the outer seal 5 is less than or equal to the longitudinal distance d separating the outer edge 4 from the inner shoulder 9 of the container 2. Similar to the figures 3 And 6 , the internal operculum 8 and external operculum 5 are also represented in a non-equilibrium state.

[0040] Once the outer lid 5 is torn, the inner lid 8 is then fully subjected to the differential pressure and tears in turn ( figure 8). With the open end 3 of the container 2 immersed in the water in the extinguisher reservoir, water is drawn into the container 2 through its open end 3 through the tears 12, 15 of the outer lid 5 and the inner lid 8, and the additive 11 contained in the floating dose 1 is mixed very rapidly with the water in the extinguisher.

[0041] The floating dose 1 according to the invention is therefore insensitive to the risk of loss of sealing under zero differential pressure, while retaining the ability to open systematically by tearing of the seals 5, 8 under a sufficient differential pressure, for example greater than 4 bars.

[0042] The embodiment described above is not limiting, and modifications may be made to it without departing from the scope of the invention. By way of example, the distance d between the outer circumferential edge 5 and the inner circumferential shoulder 9 may be less than the rupture depth hr of the outer seal 5. In this specific case, it might be necessary to provide sufficient differential pressure—typically greater than 15 or 16 bar—to ensure that the tearing of the outer seal 5 is not hindered by the presence of the inner seal 8.

Claims

1. A floating additive dose (1) for a water extinguisher comprising a water tank and means for pressurizing said water tank, the floating dose (1) comprising a longitudinal container (2) having an open end (3) provided with a circumferential outer edge (4), and sealing means of said open end (3) having an outer leaktight and frangible sealing membrane (5) of the open end (3) secured to the circumferential outer edge (4), characterized in that the sealing means further comprise an inner leaktight and frangible sealing membrane (8) which is arranged in the container (2) and which is secured to a circumferential inner shoulder (9) formed in the wall of said container (2).

2. The floating dose according to the preceding claim, characterized in that the outer membrane (5), under a differential pressure caused by the pressurization of the extinguisher tank, forms a concavity (6) in the container which tears when the longitudinal distance (h) between the circumferential outer edge (4) and the bottom of the concavity (7) reaches a determined rupture depth (hr), and in that the minimum distance (d) separating the circumferential outer edge (5) from the circumferential inner shoulder (9) is greater than or equal to the rupture depth (hr) of the outer membrane (5).

3. The floating dose (1) according to the preceding claim, characterized in that the open end (3) of the container (2) has a circular cross-sectional shape of radius r, in that the concavity (6) has the shape of a spherical cap of radius r identical to that of the open end (3) of the container (2), of curvature R and of height h = R + / - (R2 - r2 )1 / 2, and in that the rupture depth (hr) is correlated to the radius r of the open end (3) of the container (2).

4. The floating dose (1) according to the preceding claim, characterized in that the ratio between the radius r of the open end (3) of the container (2) and the distance d between the outer edge (4) and the inner shoulder (9) of the container (2) is less than or equal to 10, preferentially less than or equal to 5, and more preferentially of the order of 4.5.

5. The floating dose (1) according to any one of the preceding claims, characterized in that the distance d between the outer edge (4) and the inner shoulder (9) of the container (2) is greater than or equal to 4.5 mm.

6. The floating dose (1) according to any one of claims 1 to 5, characterized in that the inner membrane (8) and the outer member (5) are heat-sealed against the circumferential inner shoulder (9) and the circumferential outer edge (4), respectively.

7. The floating dose (1) according to any one of the preceding claims, characterized in that it comprises a handling keel (10) provided at an opposite end of the container (2).

8. The floating dose (1) according to any one of the preceding claims, characterized in that the additive (11) at most 90% of the total volume of the container (2).

9. A water extinguisher comprising a water tank and means for pressurizing said tank, characterized in that it further comprises a floating dose (1) according to any one of the preceding claims housed in the tank, and in that the outer membrane (5) is immersed in the water of the tank.

10. The extinguisher according to the preceding claim, characterized in that the differential pressure between the tank and the container (2) of the floating dose (1) after pressurizing said tank is at least equal to 4 bars.

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