EP3991805B1 - Foam supply device - Google Patents

Description

The invention relates to a foam feeder for discharging a fluorine-free foam agent, and more particularly to a foam tube for use with a portable fire extinguisher according to the preamble of claim 1, and a fire extinguishing system having such a foam feeder.

General fire extinguishing systems should be used primarily to extinguish fires known as A fires and B fires. Fires involving solids such as wood are referred to as A fires, while fires involving liquids such as heptane are referred to as B fires.

For the former, a longer spray time and good distribution on the fire object with the foam agent is required. For the latter, a high initial amount of foam and very good distribution on the fire object are required so that the fire can be covered with foam very quickly.

In addition, a fire extinguishing system must pass the so-called current test. When extinguishing a fire in an electrical system using a fire extinguisher, according to EN3-7 it is important that the fire extinguisher does not exceed a maximum permissible current value.

For this purpose, it is necessary that the droplet size of the extinguishing foam is dimensioned such that a maximum current intensity of 500 µA can be conducted to a fire extinguisher positioned 1 m away from a live metal plate. The size of the metal plate is 1 × 1 m and the applied voltage is 35 kV.

The foam suitable for extinguishing must therefore have a certain drop size that allows the foam to be thrown sufficiently far. To However, large drops result in a current that exceeds the permissible level being directed back to the fire extinguisher. If the drops are too small, this in turn means that when a burning liquid (e.g. heptane) is extinguished, the foam absorbs the burning liquid and can even cause the fire to spread.

In addition, the foam must have an optimal number of bubbles, otherwise the foam will be too light (i.e. the density of the foam is too low). This means that in unfavorable weather conditions, especially wind, the throwing distance is affected. The wind, for example, ensures that foam that is too light is tolerated and does not reach the fire site.

The applicant has already presented a foam pipe that achieves excellent results in this regard with known foam agents. The foam tube according to the prior art has a length of 65 mm. Air inlet openings through the wall of the foam tube have a width (extension in the axial direction) of 9.75 mm to ensure sufficient air supply for foam formation. If the length of the foam tube is exceeded and/or the width of the air supply openings is reduced, this leads to remarkably deteriorated results in the current test or foam formation. If the pipe is lengthened to increase the throw distance, the drops become too large, while reducing the width of the air inlet openings results in increased bubble formation.

This foam pipe is, among other things, from the publication DE 10 2006 035 349 A1 known. However, due to legal requirements, such known foam agents will no longer be permitted from 2025 at the latest, as these foam agents contain fluorine and fluorine compounds. With alternative, fluorine-free foam agents, the known foam pipe only achieves inadequate extinguishing results and therefore does not pass the current test.

It is the object of the invention to provide an improved foam supply device with a high throw, optimal foam density and reduced electrical power Conductivity of a fluorine-free foam with reduced maintenance.

The object of the invention is achieved by a foam supply device according to claim 1. Advantageous embodiments are carried out according to the dependent claims.

According to the invention, a foam supply device for ejecting a foam agent has a bottom piece for connection to a foam agent storage and a wall for forming an inner space for guiding a foam agent to a discharge opening in a longitudinal axis direction of the foam supply device. Two or more inlet openings for the foam agent, which are connected to the inner space and are designed to taper, are provided in the base piece. As a result, the flow velocity of the foam agent flowing from the foam agent storage into the foam supply device increases sharply and becomes turbulent. In addition, air openings are provided in the wall, which serve to introduce ambient air into the foam agent flow. A total length of the foam tube is between 60 and 85 mm. A passage area of each of the air holes is between 6.4 mm ² and 20.8 mm ² .

Due to the significantly higher entry speed into the interior of the foam supply device compared to the prior art, the foam agent flow is turbulent. This results in a good distribution of the foam agent. By allowing ambient air to flow through the air openings into the foam agent flow, the distribution of the fluorine-free foam agent is further optimized. Due to the high speed of the foam agent flow, a very high throw of the foam agent of 4 to 15 m is surprisingly possible compared to the prior art. This value is more than twice as high as for the foam pipe according to the prior art. The extraordinarily high throwing distance leads to significantly increased user safety.

Although the passage area of each of the air openings does not exceed a very small area of 20.8 mm ² compared to the known foam tube, the use of fluorine-free foam agents surprisingly results in the formation of a foam whose droplet size and density meets the requirements described in the introduction even exceeds this without an increased amount of air bubbles being formed. Additionally, a greater throw distance is possible, improving a user's safety as they can stay further away from the fire.

The passage area of each of the air openings is preferably 7.6 mm ² , 13.9 mm ² , 20.8 mm ² .

Measured from the inlet openings in the base piece to the ejection opening, the total length of the foam supply device can be between 60 and 72 mm or between 72 and 85 mm. This total length is preferably 65 mm, 72 mm or 79 mm. Surprisingly, tests with fluorine-free foam agents have shown that excellent results in terms of droplet formation and throwing distance can be achieved even with comparatively short foam supply devices with a length of 65 mm.

Advantageously, a dimension from an edge of the air opening closest to the ejection opening to the ejection opening in the longitudinal axis direction of the foam supply device can be 40 mm to 60 mm. Values of 42.75 mm, 46.75 mm, 48.25 mm, 49.75 mm, 53.75 mm are particularly preferred here.

In addition, longitudinal ribs which taper in the direction of the ejection opening can advantageously be provided inside the foam supply device between the air openings.

The number of air openings is advantageously two to six. A number of four is preferred. The air openings are advantageously arranged symmetrically to the central axis.

As a result, a uniform consistency of the fluorine-free foam formed is achieved over the entire cross section of the foam supply device, without any local differences occurring.

In the preferred case of four air openings, the values for the width (extension in axial length) and the passage area of each of the air openings result from the following table: Width (extent in axial length (mm) Passage area (mm ² ) 2.00 7.60 3.50 13.90 5.00 20.80 8.00 35.50 9.00 40.90

A width of 8.00 mm and 9.00 mm as well as the corresponding passage areas of 35.50 mm ² and 40.90 mm ² do not fall within the scope of the invention.

The air openings can advantageously be designed to taper inwards. Through such a reverse conical or reverse pyramid-like shape of the air openings in the wall, the air flow entering the inner space can be well channeled and its speed can be adjusted in the desired manner. The values given above are then present on the inner wall of the foam supply device. The passage area corresponds to the projected smallest inner cross-sectional area.

The number of entry openings is advantageously between two and six. Depending on the extinguishing container and extinguishing time, two or four inlet openings are preferred.

The base piece can advantageously be provided with an external thread.

This makes it possible to attach the foam supply device to the foam storage device, which can be designed as a fire extinguisher, or to a part connected to the foam storage device, such as a fire extinguishing gun or a hose. This means that a secure connection can be made using an extinguishing gun or an adapter.

The base piece can advantageously have knobs on a surface facing away from the inner space. The knobs can be used to create a distance between a sieve and the base piece. In a case where a sieve is provided, the sieve can be used to influence the foam quality.

The foam supply device can be designed to be essentially tubular as a foam tube and the inner space can have a substantially circular cross section.

A fire extinguishing system according to the invention has a foam supply device as described above. It also has a tank container that contains a fluorine-free foam agent and a propellant. An adapter or extinguishing gun has a connecting means for connection to the base piece of the foam supply device. A hose is provided to connect the tank container and the adapter or fire gun.

A sieve can be provided between the adapter or the extinguishing gun and the base piece of the foam supply device.

Advantageously, a cross-sectional area of the inner space in the base piece can be made smaller than in the ejection opening. This further optimizes the flow conditions for better foam distribution.

Part of the inlet openings can be closed to divert the foam agent flow at the end of the inlet opening connected to the inner space. The deflection of the foam agent flow creates reinforcement the turbulence and improved turbulence and thus distribution of the foam agent are achieved.

The part of the inlet openings is closed by a section of the wall. Some of the entry openings end in the material of the wall, so that only a significantly smaller passage to the inner space remains. The cross section of the end of the inlet openings, which is designed as a passage and is connected to the inner space, can be essentially semicircular.

To optimize the flow conditions, the inner space can also have several sections with cross-sectional areas of different sizes. Ribs running in the longitudinal direction of the foam supply device can also be provided on the inside of the wall. The ribs can be designed in such a way that their height continuously decreases in the direction of the inlet openings.

Advantageously, the air opening can be essentially rectangular and delimited in a direction transverse to the longitudinal axis of the foam supply device by two of the ribs.

The inner space can advantageously consist of a plurality of sections, whereby the diameter of the adjacent section in the direction of the ejection opening can be made larger, starting from a base section in the area of the base section.

A transition from the base section to a middle section adjacent to it in the direction of the ejection opening can be designed to be beveled, for example by means of a chamfer.

The air opening can advantageously be formed in the wall at an end axially opposite the ejection opening of an ejection opening section located in the area of the ejection opening. There is one on the floor piece directed edge of the air opening at the boundary area between the middle section and the ejection section.

Advantageously, an inner diameter of a base section of the inner space in the base section can be between 5mm and 9mm, a middle section can be between 7mm and 11mm and an ejection opening section in the ejection opening can be between 15mm and 25mm. An opening angle of the inlet opening can be between 55° and 65°.

The number of inlet openings is preferably two or four. The number of inlet openings preferably depends on the size of the extinguishing container, and the number of air openings can also be four. The air openings and/or the inlet openings can be arranged symmetrically to the central axis. The air openings can be provided in the area of the ejection opening section and delimited by the ribs in a direction transverse to the longitudinal axis.

By changing the geometry of the foam supply device, it is advantageously possible to set a foaming number of the foam. In particular, with the foam supply device according to the invention, different types of extinguishing containers with different container sizes, different fluorine-free foam agents, different propellants (CO2 / N2 and its amount) and different types of supply of the propellant into the extinguishing container (e.g. via a gas pipe or the propellant is located in the Extinguishing container (permanent pressure extinguisher) can be used. The values mentioned above regarding throw distance and passing the current test are always achieved.

BRIEF DESCRIPTION OF THE FIGURES

• Fig. 1 eine Ansicht einer als Schaumrohr ausgeführten Ausführungsform der Erfindung;
• Fig. 2 eine Seitenansicht der Ausführungsform mit Blickrichtung auf eine Auswurföffnung;
• Fig. 3 eine Seitenansicht der Ausführungsform mit Blickrichtung auf ein Bodenstück;
• Fig. 4 einen Schnitt entlang der Linie A-A der Fig. 2;
• Fig. 5 einen Schnitt entlang der Linie B-B der Fig. 4;
• Fig. 6 den Schnitt der Fig. 4 mit einer Darstellung der Strömungsverhältnisse in dem Inneren des Schaumrohrs;
• Fig. 7 den Schnitt der Fig. 5 mit einer Darstellung der Strömungsverhältnisse.
• Fig. 8a und b jeweils eine derzeit bevorzugte Ausführungsformen eines Schaumrohrs in schematischer Weise.

Shown in the figures:

• Fig. 1 a view of an embodiment of the invention designed as a foam tube;
• Fig. 2 a side view of the embodiment looking towards an ejection opening;
• Fig. 3 a side view of the embodiment looking towards a base piece;
• Fig. 4 a cut along line AA of the Fig. 2 ;
• Fig. 5 a cut along the line BB of the Fig. 4 ;
• Fig. 6 the cut of the Fig. 4 with a representation of the flow conditions inside the foam tube;
• Fig. 7 the cut of the Fig. 5 with a representation of the flow conditions.
• Fig. 8a and b each a currently preferred embodiment of a foam tube in a schematic manner.

A structure of a foam supply device according to the invention is based on Fig. 1 to 5 described. According to the embodiment shown, the foam supply device is designed as a foam tube.

The foam tube is essentially formed in the shape of a cylinder. At a first end of the foam tube there is a base piece 1 whose diameter is smaller than the diameter of the cylinder. In the area of the base piece 1 there is an external thread 11 for attaching the foam pipe to a fire extinguisher, a hose, a fire extinguishing gun or the like. intended. According to the embodiment, the diameter of the base piece is 16 mm with a length of 10 mm compared to a diameter of the foam tube of 20.5 mm with a total length between 60 and 85 mm.

Two tapered inlet openings 7 are provided in the bottom of the base piece, the tapered ends of which partially end like a blind hole in a wall 3 of the cylinder. The remaining portion of the tapered ends represents a Connection to a base section of an inner space of the cylinder defined within the base piece 1 by a wall 3. The remaining part of the tapered ends is essentially semicircular. The opening angle of the inlet openings 11 is 60° according to the embodiment. The inner diameter of the base piece section is 7 mm.

Adjacent to the base portion in the longitudinal axis direction of the cylinder, a center portion is provided, the diameter of which is 9 mm and a length of 6.75 mm.

Adjacent to the middle section, the wall 3 defines an ejection section and an ejection opening 5 in the longitudinal axis direction of the cylinder on the base section. In an area of the ejection section adjacent to the base section, four air inlet openings 9 are provided in the wall 3, through which ambient air can enter the foam tube . The inner diameter of the ejection section is 19 mm.

In the area of the middle section, the outer diameter of the foam tube is 20.5 mm while the outer diameter of the foam tube in the area of the ejection section is 22 mm.

The width b1 (corresponds to an extension in the direction of the longitudinal axis of the foam tube) of the air inlet openings 9 is between 2 and 9 mm. An inlet area of each of the air inlet openings 9 for the air is between 7.6 mm ² and 20.8 mm ² . According to a currently preferred embodiment, which consists of Fig. 8a As can be seen, the entry area of each of the air inlet openings 9 is 13.9 mm ² . The width bl is 3.5 mm. However, it should be noted that due to manufacturing tolerances, deviations of approximately 10% from these values may occur.

In the circumferential direction, the air inlet openings 9 are delimited by longitudinal ribs 13. The longitudinal ribs 13 are provided on the inner wall of the ejection section and have a width of 3.9 mm. The height of the longitudinal ribs 13 at its end adjacent to the middle section is dimensioned such that there is a uniform transition from the wall of the middle section to the longitudinal ribs 13, while the transition to the area of the ejection space next to the longitudinal ribs takes place suddenly. The longitudinal ribs 13 are designed to taper towards the ejection opening and merge into the wall 3 in a front area of the ejection space. Due to the longitudinal ribs 13, the passage surface of each air opening 9 has a trapezoidal shape in a top view. This is for example from the Fig. 1 visible.

The functionality of the foam tube is determined by the 6 and 7 visible.

After appropriate activation, a foam agent flows from a foam agent reservoir, which can be designed as a fire extinguisher, for example, into the foam pipe connected to it via the external thread. In the Figs. 6 and 7 This foam agent stream is marked by solid arrows.

After passing through the tapered inlet openings 7 in the base piece 1, the foam agent flow is strongly swirled as it enters the base piece section through the openings, which are reduced to the essentially semicircular shape, and then in the form of a turbulent flow through the base piece section and the middle section into the ejection section to stream. In the ejection section, ambient air is sucked into the ejection section via the air inlet openings 9 by the flow of the foam agent and mixed with the foam agent flow. The ambient air is in Figs. 6 and 7 shown by dashed arrows. An optimized mixture of air and foam agent is created, which is ejected through the ejection opening 5.

The Figures 8a and 8b each show a foam pipe, not to scale. At the in Fig. 8a shown and not according to the invention, a total length I of the foam tube is 79 mm. The width b1 of the air supply openings 9 is 3.5 mm, which results in a passage area of 13.9 mm ² for each air opening. The length IA from the edge of the air supply opening 9 directed towards the ejection opening 5 to the ejection opening 5 is 55.25 mm. It is noted that the total length I of the foam tube, the width b1 of the air supply openings as well as the length IA are measured from the edge of the air supply opening facing the ejection opening to the ejection opening parallel to the axis of the foam tube.

In the in the Fig. 8b The foam tube according to the invention shown as an example has a total length of 65 mm and the width b1 of the air supply openings is 2 mm. The figure here is not to scale, but rather schematic like the other figures. Therefore, other dimensions cannot be inferred from the representation of the width b1 in the figure.

In addition, a length IA from the edge of the air supply opening 9 directed towards the ejection opening 5 to the ejection opening 5 is 42.75 mm. Here too, the total length I of the foam tube, the width b1 of the air supply openings as well as the length IA are measured from the edge of the air supply opening directed towards the ejection opening to the ejection opening parallel to the axis of the foam tube.

In the in the Fig. 8b In the example shown, the base piece is provided with knobs 17, which create a distance from a sieve that can be used as a pressure reducer. In addition, the sieve can influence the foam formation in the desired way. Both examples also show an area 15 that has no technical significance but is intended for attaching a company logo, etc.

Excellent values were measured with both foam pipes in tests with different extinguishing containers (hand-held fire extinguishers with a capacity of between 7.2 and 8.2 liters and so-called trolleys with a capacity of between 25 and 200 liters) in the current test mentioned at the beginning. The current transmitted to the fire extinguisher was between 80 and 150 µA. In addition, a foam with excellent density was formed, which can be thrown approximately 4 to 12 m without changing its composition.

When using trolleys as fire extinguishers, it has been found that it is particularly advantageous to use foam pipes with four inlet openings, since such fire extinguishers are primarily used in commercial and industrial areas, where greater throwing distances may be required in the event of a fire.

Claims (15)

1. A foam supply device for ejecting a fluorine-free foaming agent comprising

   a bottom piece (1) for connection to a foam agent reservoir,

   a wall (3) for forming an inner space for guiding a foam agent in a longitudinal axis direction of the foam supply device to a discharge opening (5), wherein inlet openings (7) for the foam agent connected to the inner space are provided in the bottom piece (1),

   wherein

   the inlet openings (7) are tapered so that the flow velocity of the foam medium flowing from the foam medium reservoir into the foam supply device increases and wherein

   a plurality of air openings (9) is provided in the wall (3) for introducing ambient air into the foam medium flow, wherein

   measured from the inlet openings (7) in the bottom piece (1) to the ejection opening (5), an total length of the foam supply device is between 60 and 85 mm,

   characterised in that

   a passage area of each of the air openings (9) is between 6.4 mm² and 20.8 mm².
2. The foam supply device according to claim 1, wherein
   the passage area of each of the air openings (9) is 7.6 mm² or 13.9 mm² or 20.8 mm².
3. The foam supply device according to claim 1 or 2, wherein
   measured from the inlet openings (7) in the bottom piece (1) to the ejection opening (5), the total length of the foam supply device is between 60 and 72 mm or between 72 and 85 mm.
4. The foam supply device according to claim 3, wherein
   measured from the inlet openings (7) in the base piece (1) to the ejection opening (5), the total length of the foam supply device is 65 mm or 72 mm or 79 mm.
5. The foam supply device according to any one of claims 1 to 4, wherein
   a dimension (lA) from an edge of the air opening (9) closest to the ejection opening (5) to the ejection opening (5) in the longitudinal axis direction of the foam supply device is 40 mm to 60 mm.
6. The foam supply device according to claim 5, wherein
   the dimension (lA) from the edge of an air opening (9) closest to the ejection opening (5) to the ejection opening (5) in the longitudinal axis direction of the foam supply device is 42.75 mm or 46.75 mm or 48.25 mm or 49.75 mm or 53.75 mm.
7. The foam supply device according to any one of claims 1 to 6, wherein
   longitudinal ribs (13) are provided in the interior of the foam supply device between the air openings (9), which ribs extend in a tapering manner in the direction of the ejection opening (5).
8. The foam supply device according to any one of claims 1 to 7, wherein
   the number of air openings (9) is two to six, and the air openings (9) are arranged symmetrically with respect to the central axis, the number of air openings preferably being four.
9. The foam supply device according to any one of claims 1 to 8, wherein the air openings (9) are designed to taper inwards.
10. The foam supply device according to any one of claims 1 to 9, wherein
    the number of inlet openings (7) is between two and six, the number of inlet openings (7) preferably being two or four.
11. The foam supply device according to any one of claims 1 to 10, wherein
    the bottom piece (1) is provided with an external thread (11).
12. The foam supply device according to any one of claims 1 to 11, wherein
    the bottom piece (1) has protrusions (17) on a surface facing away from the inner space.
13. The foam supply device according to any one of claims 1 to 12, wherein
    the foam supply device is substantially tubular as a foam pipe and the inner space has a substantially circular cross-section.
14. A fire extinguishing system comprising a foam supply device according to any one of claims 1 to 13, and comprising

    a tank container holding a fluorine-free foam agent and a propellant,

    an adapter or an extinguishing gun with a connecting means for connection to the bottom piece (1) of the foam supply device, and

    a hose connecting the tank container and the adapter or extinguishing gun.
15. The fire extinguishing system according to claim 14, wherein a screen is provided between the adapter or extinguishing gun and the bottom piece (1) of the foam supply device.

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