EP3991805A1 - Foam supply device - Google Patents

Abstract

The invention relates to a foam feeder for ejecting a foaming agent, having a bottom piece for connection to a foaming agent reservoir, and a wall (3) for forming an inner space to guide a foaming agent in a longitudinal axis direction of the foaming agent to an ejection opening (5). Inlet openings (7) connected to the inner space for the foaming agent are provided in the bottom piece. The inlet openings (7) are tapered so that the flow rate of the foaming agent flowing from the foaming agent store into the foaming agent increases. A plurality of air openings (9) are provided in the wall (3) for introducing ambient air into the flow of foam agent. A total length of the foam supplier is between 72 and 85 mm, and a passage area of each of the air holes (9) is between 6.4 mm ² and 40.9 mm ² .

Description

The invention relates to a foam supply device for ejecting a foaming agent, and in particular to a foam pipe for use with a portable fire extinguisher according to the preamble of claim 1, and a fire extinguishing system with such a foam supply device.

General fire extinguishing systems should be usable primarily for extinguishing fires designated as A fire and B fire. A fires are fires involving solids such as wood, while B fires are fires involving liquids such as heptane.

For the former, a longer spraying time and good distribution on the fire object with the foaming agent is required. The latter requires a large initial amount of foam and very good distribution on the fire object 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 it is necessary that the droplet size of the extinguishing foam is dimensioned in such a way that a maximum current of 500 µA can be conducted to a fire extinguisher set up 1 m away from a live metal plate. The size of the metal plate is 1 x 1 m and the applied voltage is 35 kV.

The foam that is suitable for extinguishing must therefore have a certain droplet size that allows the foam to be thrown sufficiently far. to however, large drops will result in excess current being conducted back to the extinguisher. If the droplets are too small, this in turn means that in the event that a burning liquid (eg heptane) is extinguished, the foam will absorb the burning liquid and thereby even spread the fire.

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 when it is windy, the throwing distance is impaired. The wind ensures, for example, that foam that is too light is tolerated and does not reach the site of the fire.

The applicant has already presented a foam tube that achieves excellent results in this respect with known foaming 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 significantly worse results in the flow test or foam formation. If the tube is lengthened to increase the range, the droplets become too large, while reducing the width of the air inlet openings increases the formation of bubbles.

This foam tube is, inter alia, from the publication DE 10 2006 035 349 A1 famous. However, due to legal requirements, such known foaming agents will no longer be permitted by 2025 at the latest, since these foaming agents contain fluorine and fluorine compounds. With alternative, fluorine-free foam agents, the well-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 distance, optimum foam density and reduced electrical power Provide 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 present invention, a foam feeder for ejecting a foaming agent has a bottom piece for connection with a foaming agent reservoir and a wall for forming an inner space for guiding a foaming agent in a longitudinal axis direction of the foaming agent to a discharge port. In this case, two or more inlet openings for the foaming agent, which are connected to the inner space and are tapered, are provided in the base piece. As a result, the flow velocity of the foaming agent flowing from the foaming agent reservoir into the foam supply device increases sharply and becomes turbulent. In addition, air openings are provided in the wall, which are used to introduce ambient air into the flow of foam agent. 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 40.9 mm ² .

The flow of foam agent into the interior of the foam supply device is turbulent due to the significantly higher entry speed compared to the prior art. This results in a good distribution of the foam agent. The distribution of the fluorine-free foam compound is further optimized by the inflow of ambient air through the air openings into the foam compound flow. Surprisingly, the high speed of the foaming agent flow also allows the foaming agent to be thrown at a distance of 4 to 15 m, which is very high compared to the prior art. This value is more than double that of the prior art foam tube. The extraordinarily high throw leads to a significantly increased safety of a user.

Although the total area of the air openings does not exceed a very small area of 40.9 mm ² compared to the known foam pipe, when using fluorine-free foaming agents, surprisingly a foam is formed whose droplet size and density meets the requirements described in the introduction or even even surpassed without an increased amount of air bubbles being formed. In addition, a longer throw distance is possible, which improves a user's safety since he can stay further away from the fire.

Preferably, the passage area of each of the air openings is 7.6 mm ² , 13.9 mm ² , 20.8 mm ² , 35.5 mm ² or 40.9 mm ² .
Measured from the inlet openings in the bottom 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 overall length is preferably 65 mm, 72 mm or 79 mm. Surprisingly, experiments with fluorine-free foaming 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, 55.25 mm or 56.75 mm are particularly preferred here.

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

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 local differences occurring.

In the preferred case of four air openings, values for the width (length in axial length) and the passage area of each of the air openings result from the following table: Width (extension 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

The air openings can advantageously be designed to taper inwards. With such an inverted conical or inverted pyramidal 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 inlet openings is advantageously between two and six. Two or four inlet openings are preferred, depending on the extinguishing tank and extinguishing duration.

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

This allows the foam supply device to be attached to the foam storage medium, which can be designed as a fire extinguisher, or to a part connected to the foam storage medium, such as a fire pistol or a hose. In this way, a secure connection can be established with an extinguishing pistol or an adapter.

Advantageously, the bottom piece can have knobs on a surface facing away from the inner space. The nubs can be used to create a distance between a sieve and the bottom piece. In a case where a screen is provided, the foam quality can be influenced by the screen.

The foam supply device can be configured as a substantially tubular foam pipe 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 containing a fluorine-free foam concentrate and a propellant. An adapter or extinguishing pistol has a connection 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 extinguishing gun.

A screen can be provided between the adapter or the extinguishing pistol 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. As a result, the flow conditions are further optimized in terms of better foam agent distribution.

Part of the inlet openings can be closed off at the end of the inlet opening connected to the inner space in order to deflect the foaming agent flow. By deflecting the foaming agent flow, the turbulence is increased and the swirling and thus distribution of the foaming agent is improved.

In this case, the part of the inlet openings is closed by a section of the wall. A part of the inlet openings ends in the material of the wall, so that only a much smaller passage to the inner space remains. The cross section of the end of the inlet openings designed as a passage connected to the inner space can be essentially semicircular.

In order 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 decreases continuously in the direction of the inlet openings.

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

Advantageously, the inner space can consist of a large number of sections, in which case, starting from a base piece section in the region of the base piece, the diameter of the respectively adjoining section can be made larger in the direction of the ejection opening.

A transition from the base piece section to a central section adjoining this in the direction of the ejection opening can be designed to be beveled, e.g. by means of a chamfer.

Advantageously, the air opening can be formed in the wall at an end of an ejection opening section lying in the area of the ejection opening that is axially opposite to the ejection opening. In this case, an edge of the air opening directed towards the bottom piece lies at the boundary area between the middle section and the ejection section.

Advantageously, an inner diameter of a bottom piece portion of the inner space at the bottom piece may be between 5mm and 9mm, a middle section between 7mm and 11mm, and an ejection opening section at the ejection opening 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 can be 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 adjust 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 foaming agents, different propellants (CO2 / N2 and its amount) and different ways of supplying the propellant to the extinguishing container (e.g. via a gas pipe or the propellant is in the Extinguishing containers (permanent pressure extinguishers)) are used. The values mentioned above in terms of 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.

In the figures shows:

• 1 a view of an embodiment of the invention designed as a foam pipe;
• 2 a side view of the embodiment looking towards an ejection opening;
• 3 a side view of the embodiment looking towards a base piece;
• 4 a cut along line AA of 2 ;
• figure 5 a cut along the line BB of the 4 ;
• 6 the cut of the 4 with a representation of the flow conditions in the interior of the foam pipe;
• 7 the cut of the figure 5 with a representation of the flow conditions.
• Figure 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 the Figures 1 to 5 described. According to the illustrated embodiment, the foam supply device is designed as a foam tube.

The foam tube is formed substantially in the shape of a cylinder. At a first end of the foam pipe there is a bottom piece 1, the diameter of which 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 tube to a fire extinguisher, a hose, a fire extinguisher or the like. intended. According to the embodiment, the diameter of the bottom 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 of between 60 and 85 mm.

Two tapering inlet openings 7 are provided in the base of the base piece, the tapered ends of which partially end like a blind hole in a wall 3 of the cylinder. The remaining part of the tapered ends connects with a bottom portion of an inner space of the cylinder defined inside the bottom 1 by a wall 3 . The remaining portion of the tapered ends is formed into a generally semi-circular shape. Of the According to the embodiment, the opening angle of the inlet openings 11 is 60°. The inner diameter of the bottom piece section is 7 mm.

Adjacent to the bottom piece portion, in the longitudinal axis direction of the cylinder, there is provided a central portion whose diameter is 9 mm by a length of 6.75 mm.

Adjoining the middle section, the wall 3 defines an ejection section and an ejection opening 5 in the longitudinal axis direction of the cylinder at the head section. In an area of the ejection section bordering on the head 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 pipe is 20.5 mm, while the outer diameter of the foam pipe 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. A total entry area of the air entry openings 9 for the air is between 7.6 mm ² and 40.9 mm ² . According to a presently preferred embodiment, which is known from Figure 8a As can be seen, the total entry area of the air entry openings 9 is 13.9 mm ² . The width bl amounts to 3.5 mm. It should be noted, however, that deviations from these values of approx. 10% can occur due to manufacturing tolerances.

The air inlet openings 9 are delimited by longitudinal ribs 13 in the circumferential direction. 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 their end adjacent to the middle section is such that there is a smooth transition from the wall of the middle section to the longitudinal ribs 13, while the transition to the area of the ejection chamber next to the Longitudinal ribs occurs abruptly. The longitudinal ribs 13 taper towards the ejection opening and merge into the wall 3 in a front area of the ejection chamber. Due to the longitudinal ribs 13, the passage surface of each air hole 9 has a trapezoidal shape in a plan view. This is eg from the 1 apparent.

The functioning of the foam tube is from the Figures 6 and 7 apparent.

After a corresponding activation, a foaming agent flows from a foaming 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 Figures 6 and 7 this foam agent flow is marked by continuous arrows.

After passing through the tapering inlet openings 7 in the head piece 1, the foam agent flow is strongly swirled on entering the head piece section through the openings reduced to the essentially semi-circular shape, and then in the form of a turbulent flow through the head 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 and mixed with the foaming agent flow by the flow of the foaming agent. The ambient air is in Figures 6 and 7 represented by dashed arrows. This creates an optimized mixture of air and foam agent, which is ejected through the ejection opening 5.

the figs 8a and 8b each show a foam pipe according to a presently preferred embodiment, not to scale. In the in the Figure 8a foam tube shown, the total length I of the foam tube is 79 mm. The width bl 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 pointed out that the total length I of the foam pipe, the width bl of the air supply openings as well as the length IA from the to the Ejection opening directed edge of the air supply opening to the ejection opening parallel to the axis of the foam pipe.

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

In addition, a length IA from the edge of the air supply opening 9 directed to 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 bl of the air supply openings and the length IA from the edge of the air supply opening directed towards the ejection opening to the ejection opening are measured parallel to the axis of the foam tube.

In the in the Figure 8b example shown, the bottom piece is provided with knobs 17 that create a distance to a screen that can be used as a pressure reducer. In addition, the screen can influence the formation of foam in a desired manner. Both examples also show an area 15 that has no technical significance, but is provided for attaching a company logo, etc.

With both foam tubes, excellent values were measured in tests with various extinguishing containers (portable fire extinguishers with between 7.2 and 8.2 l content and so-called trolleys with between 25 and 200 l content) in the aforementioned current test. 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 from approx. 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 tubes with four inlet openings, since Such fire extinguishers are mainly used in commercial and industrial areas, where greater throw distances may be required in the event of a fire.

Claims (15)

Foam supply device for ejecting a foaming agent
a base piece (1) for connection to a foam compound reservoir,
a wall (3) for forming an inner space for guiding a foaming agent to a discharge opening (5) in a longitudinal axis direction of the foaming device, wherein inlet openings (7) for the foaming agent connected to the inner space are provided in the base piece (1),
whereby
the inlet openings (7) are designed to be tapered, so that the flow rate of the foaming agent flowing from the foaming agent storage device into the foaming agent increases, and wherein
in the wall (3) a plurality of air openings (9) for introducing ambient air into the flow of foaming agent is provided, 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 between 60 and 85 mm,
characterized in that
a passage area of each of the air openings (9) is between 6.4 mm ² and 40.9 mm ² . Foam delivery device according to claim 1, wherein
the passage area of each of the air openings (9) is 7.6 mm ² or 13.9 mm ² or 20.8 mm ² or 35.5 mm ² or 40.9 mm ² . Foam delivery device according to claim 1 or 2, 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 between 60 and 72 mm or between 72 and 85 mm. Foam delivery 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. Foam delivery device according to any one of claims 1 to 4, wherein
a dimension (IA) 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 supplier is 40 mm to 60 mm. Foam delivery device according to claim 5, wherein
the dimension (IA) 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 or 55.25 mm or 56.75 mm. Foam delivery device according to any one of claims 1 to 6, wherein
inside the foam supply device between the air openings (9) longitudinal ribs (13) are provided, which extend tapering in the direction of the ejection opening (5). Foam delivery 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 to the central axis, the number of air openings preferably being four. Foam supply device according to one of Claims 1 to 8, in which the air openings (9) are designed to taper inwards. Foam delivery 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. Foam delivery device according to any one of claims 1 to 10, wherein
the bottom piece (1) is provided with an external thread (11). Foam delivery device according to any one of claims 1 to 11, wherein
the bottom piece (1) has knobs (17) on a surface facing away from the inner space. Foam delivery device according to any one of claims 1 to 12, wherein
the foam supply device is essentially tubular as a foam tube and the inner space has an essentially circular cross-section. A fire extinguishing system comprising a foam supply device according to any one of claims 1 to 13, and comprising
a tank containing a fluorine-free foam concentrate and a propellant,
an adapter or an extinguishing pistol with a connection means for connection to the base piece 1 of the foam supply device, and
a hose connecting the tank container and the adapter or the extinguishing pistol. Fire extinguishing system according to claim 14, wherein a screen is provided between the adapter or the extinguishing pistol and the base piece (1) of the foam supply device.

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