I Various systems have been suggested for achieving extinguishing in the event of a fire, as is known, which systems are sufficiently efficient to make it possible to evacuate a building such that injury to persons is prevented.

The water stations with hoses that are installed in hotels and in other frequently visited buildings are normally unsatisfactory, not only because it takes time to connect nozzles, hoses, etc. , and the effect is often unsatisfactory, but also because it is not possible due to aesthetic considerations to arrange the water outlet in the most appropriate manner.

Furthermore, it must also be considered that the water damage that arises as a consequence of extinguishing with water is often considerable.

Sprinkler systems have the advantage of, in a manner of speaking, always being in a state of readiness, but the effect is far too low to be able to guarantee safe evacuation.

Foam extinguishers are efficient, but since the foam is particularly bulky even before it is deployed, such arrangements can be used only to a limited extent, and it cannot be expected that they will be used completely rationally when panic has arisen. This is of major significance due to the short period during which output of foam from a container of limited size can take place. Powder extinguishers are principally associated with the disadvantage of having a very limited radius of action and a very limited time of action.

The aim of the invention, therefore, has been to achieve a simple and cheap arrangement that is efficient enough to make it possible to evacuate a building, means of transport. etc.

The invention has been designed in accordance with the attached claims, in order to achieve this and other aims.

Some embodiments of the invention are shown in the attached drawings for the purpose of example.

Figure 1 thus shows in principle a water pipe with an attached device for the production of foam.

Figure 2 shows a water pipe with an attached extinguishing unit.

Figure 3 constitutes a plan view of a part of a building with a fire extinguishing arrangement according to the invention.

Figure 4 shows a perspective view of a modified arrangement, and Figure 5 constitutes a section through the arrangement according to Figure 4, and finally, Figure 6 constitutes a frontal view of a fixed fire extinguishing unit.

According to the invention, problems of the type described above during the extinguishing of a fire are solved through a compound, which will be referred to as"foam compound", that forms an extinguishing foam when combined with water, and which is maintained until the occasion of use separate from the water, and through the said water, which acts not only in the formation of the foam but also as propellant for it, is placed under pressure. It is also appropriate that the water is obtained from a water pipe of essentially conventional design.

A foam compound is used for the production of extinguishing foam by being mixed with water in predetermined proportions. The foam that is developed in this way has a significantly greater volume than the combined volume of the water and the compound, and it must be realised that it will be possible, by storing only the relatively low volume of foam compound, to achieve a very great volume of foam, since the amount of water is added gradually, at least in buildings that have a fixed water supply installation. One litre of foam compound provides approximately lm3 of foam.

The arrangement in its simplest form according to Figure 1 comprises a water pipe 1, provided with a number of outlets 2 and the stopcocks 3 associated with these. A tube 4 can be connected to each of these outlets, which tube communicates via a second tube 5 with a dosing device 6, which in turn is connected through a tube 7 to a container 8 containing the foam compound.

When the stopcock 3 is opened, water under pressure will flow through the tube 4 towards a spreader nozzle 9 that is connected to the tube. The dosing device 6, however, achieves mixing of the water during its passage through the tube 4 with a specific amount of foam compound, leading to the medium that leaves the relevant nozzle consisting of foam.

It is appropriate in practice to combine the container that contains the foam compound with the dosing device to create a foam extinguisher unit that can be connected in a simple manner to any outlet on the water pipe, and it is further appropriate to construct the dosing device in such a manner that it is controlled directly by the water pressure.

Figure 2 constitutes an example of such a device. The foam extinguishing unit has been given the general reference numeral 10, and it is constituted by a tube 11 that forms at one end an externally directed connection flange 12. A throttle nozzle 13 and a diffusion nozzle 14 are arranged in the tube 11, and the tube demonstrates a thread 15 or similar for the attachment of a spreader nozzle 16 at the opposite end to that of the flange 12. The tube 11 is in communication via a thinner tube 17 with a closed container 18, which contains the foam compound 19. It is appropriate that a hole 20 for air intake, which is normally held closed by a check valve 21, is arranged in the upper part of the container. The nozzles 13 and 14 are designed and arranged relative to each other and to the tube 17 such that they form, in combination with the said tube 17 and the tube 11, an ejector pump, and it will be realised that the water that is held under pressure will, on the opening of the stopcock, achieve not only the dosed mixing of water and foam compound, but also the formation of foam and the output of foam. Naturally, the stopcock 3 should be designed such that it can be rapidly turned to a fully open position, and naturally, known devices can be arranged to achieve instantaneously the desired suction effect through hoses.

Arrangements of the type described here can be so designed that they can produce continuous pathways or carpets of foam, and such an design is shown in Figure 3, intended for, for example, passage from a hotel room to a lift or similar.

In this connection, 24 denotes hotel rooms and 25 denotes corridors leading to a lift 26. By laying down a water pipe 1 according to Figure 3 and by attaching to several of the outputs from this pipe foam extinguishing units 10 with spreader nozzles oriented according to a system determined in advance, it is possible when the units are activated to achieve continuous carpets of foam 27, on which the hotel guests can advance to reach the lift 26.

Naturally, it is possible to automate the procedure of extinguishing the fire to a high degree by, for example, allowing a fire alarm to initiate the procedure for extinguishing the fire a short time after the actual alarm has been given.

In order to exploit the available amount of foam compound, arrangements can be made in order to interrupt the process after a predetermined period and subsequently resume it, either automatically after a predetermined period or following manual influence.

It is also possible to design the foam extinguishing units 28, according to Figure 4, in such a manner that they normally adopt a position of preparedness, from which they very rapidly can be brought into an operational position. In the design shown, a number of such foam extinguishing units 28 each hang from a thread 29, attached for example to the ceiling directly above an outlet 2 in a water pipe 1. The foam extinguishing units in this way demonstrate control sections 31a, 31b that maintain them in a straddle position above the pipe 1. The container 32 for each of the units can thus be positioned under the pipe 1 and a tube 33 can be placed in connection through a thinner tube 34 with the container 32 in essentially the same manner as the tube 17 in Figure 2, and the tube 33 can thus via a bent section open out above the relevant outlet 2. The outlet can, in this way, demonstrate a valve seating 35, and a valve body 36 can interact in a sealing manner with the valve seating 35 through the effect of the water pressure, appropriately supported by a spring 37. A release rod 38 for the foam extinguishing unit is so arranged that when the foam extinguishing unit is allowed to fall, through the cutting, for example, of the thread 29, it rapidly opens the valve 36 and in this way initiates the extinguishing procedure. In the design shown, a calibrated ball 39 suspended in the tube 33 is intended to provide the negative pressure that ensures that an amount of foam proportional to the amount of flowing water is added to the water for the production of foam.

Naturally, the water pipe 1 does not need to be stationary, and a hose fed by a motor-driven pump can be envisaged, which pipe demonstrates a number of outputs or, where relevant, preinstalled extinguishing units according to the invention. Naturally it is also possible to connect, for example, a high-pressure pump for the purposes of increasing the pressure. A mobile arrangement can thus be combined with a fixed arrangement, for example, of the type described above, and interaction between fire extinguishing arrangements that are present on the site and mobile arrangements brought into place by, for example, the fire service, can thus arise, resulting in a particularly efficient fire extinguishing process.

It can be mentioned as an example that 200 litres of foam per minute have been achieved at a working pressure of 2.5 kg, and approximately 500 litres per minute at a pressure of 6 kg.

Using a container with a volume of 3 litres, a period of action of approximately 15 minutes is achieved at a working pressure of 2.5 kg, which can be compared to the period of action of approximately 20-30 seconds offered by a powder extinguisher. At the same time, a distance of action of 4-5 metres is obtained, while it is necessary to approach essentially right up to the fire when using a powder extinguisher.

The fire extinguishing unit in the embodiment shown in Figure 6 has the form of a cabinet 40 that demonstrates on its front surface an opening 41 through which a length of hose 42 designed for the intended use can be inserted and removed. The venturi tube 17 that is used for withdrawal by suction of the foam compound from the exchangeable container 18 is terminated at its lower end by a strainer or a filter 43, and the supply of water takes place through a throttle valve 44, which is connected to the actual ejector, and which is calibrated according to the dimension of the hose that is being used in the particular situation. The spreader nozzle 45 is located readily available in the upper, open part of the cabinet. The fire extinguishing operation is produced by means of a stopcock 46, the control lever of which is located easily accessible on the front surface of the cabinet.