WO2006010981A1

WO2006010981A1 - Device for extinguishing a fire which has started in particular inside the housing of electrical apparatus

Info

Publication number: WO2006010981A1
Application number: PCT/IB2004/002207
Authority: WO
Inventors: Enrico Vignati; Bruno Vignati; Concezio Cerasi
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-07-01
Filing date: 2004-07-01
Publication date: 2006-02-02
Anticipated expiration: 2007-01-01

Abstract

Device for extinguishing an incipient fire, comprising a container (10; 110) which has, arranged inside it, a switch (20) which can be closed by a pressurised extinguishing fluid (30) introduced inside the said container (10, 110).

Description

DEVICE FOR EXTINGUISHING A FIRE WHICH HAS STARTED IN PARTICULAR INSIDE THE HOUSING OF ELECTRICAL APPARATUS

DESCRIPTION The present invention relates to a device for extinguishing an incipient fire.

It is known in the technical sector relating to the installation of electric power distribution systems that there is a need to provide devices for extinguishing fires of electrical origin which may break out for example inside junction boxes, electric control panels and the like.

It is also known that attempts have been made to prevent the outbreak of a fire both by means of suitable techniques for installing and mounting the systems and apparatus and by the use of suitable fireproof materials.

Although fulfilling their function, these techniques are however unsuitable owing to the high degree of unreliability resulting from numerous variable factors such as: use of materials which are not of optimum quality; overloading of the systems designed for initial requirements different from the actual requirements; routine maintenance which is not regularly performed; modifications of the systems without prior redesigning thereof; poor operation of the components over time; wear and deterioration of the system; lightening strikes.

As a result, a fire breaks out and tends to spread along the electrical network and must therefore be extinguished.

Also known are, for example, devices according to

GB 2,322,449, which are able to detect the variation in pressure inside electrical housing and are associated with extinguishing-gas containers which, upon detection of a variation in pressure following the start of a fire, cause opening of the container and release of the gas in order to put out the incipient fire.

These known devices, however, have numerous drawbacks associated with the fact that: the device must always be added to the existing system with the addition of further components; it intervenes with a certain delay due to the need to heat up the gas containing tube which, being straight, may also be at a distance from the heat source which produces breakage thereof.

In addition to this, there are cases where the presence of an auxiliary electric wire for the return connection to the main switch and/or housing supply is required in order to interrupt the power supply; this results in the need for operation of the main switch in order to interrupt the electric power supply, which operation is often impossible since damage to the switch is the cause of the outbreak of the fire. The technical problem which is posed, therefore, is that of providing a device which is able to extinguish a fire which has started inside electrical systems and provide a solution to the said problems of the prior art, which device can be activated immediately and can interrupt the electric power supply without the need for operations by an external user and without the need for auxiliary means outside the device.

Within the scope of this problem it is furthermore required that this device should have small dimensions and be easy and inexpensive to implement and incorporate both in new components for electrical systems and in electrical systems which already exist.

These results are obtained according to the present invention by a device for extinguishing the outbreak of a fire, comprising a container having, arranged inside it, at least one switch which can be closed by an extinguishing fluid under pressure which is introduced inside the said container. Further details may be obtained from the following description of a non-limiting example of embodiment of the subject of the present invention provided with reference to the accompanying drawings, in which:

Figure 1 shows an exploded view of a first embodiment of the device according to the present invention;

- Figure 2 shows a schematic cross-section along a vertical longitudinal plane of the container according to Fig. 1 in the assembled condition; - Figure 3 shows a front view of the side with switch of the device according to Fig. 1;

Figure 4 shows a top plan view of the side according to Figure 2;

- Figure 5 shows a schematic cross-section along the plane indicated by V-V in Figure 3;

- Figure 6 shows a schematic cross-section along the plane indicated by VI-VI in Figure 4;

- Figure 7 shows a schematic cross-section along the plane indicated by VII-VII in Fig. 4; - Figure 8 shows a perspective view of a second embodiment of the device according to the present invention;

- Figure 9 shows a bottom plan view of the device according to Fig. 8; - Figure 10 shows a schematic cross-section along the plane indicated by X-X in Figure 9;

- Figure 11 shows a schematic cross-section along the plane indicated by XI-XI in Figure 9;

Figure 12 shows a perspective view of an electric distribution panel equipped with the fire- prevention device according to the present invention.

As shown, the fire-prevention device for electrical systems and the like according to the present invention comprises a sealed container 10, at least two sides 11, 12, which have an associated one¬ way valve lla, 12a respectively able to allow supplying of a fluid under pressure 30 and discharging of the air so as to allow entry of the fluid.

Said fluid is suitably formed by an extinguishing agent able to counteract the outbreak of a fire and extinguish the fire once it has started.

One 11 of the two sides of the container is also provided with an electric switch 20 formed by an insulating base 21, which in the example is incorporated in and coincides with the side 11 of the container which has, arranged inside it, two electric contacts 22 which are accessible from the outside, for the connection of respective electric wires Ia and Ib.

Said contacts 22 also have a conducting surface 22a which is exposed towards the inside of the container and is able to come into contact with a respective pin 23a projecting from a flat member 23 forming the closing element of the switch.

In greater detail the said flat member 23 is constrained to the first end of at least one spring 25, the other end of which is fixed to the insulating base of the switch 20 so that, in the rest condition, the spring 25 pushes against the flat member 23 so as to open the switch. The flat member 23 is also associated with an insulating element 23b, for example of the 0-ring type perimetrally arranged around the said flat member (Fig. 5) .

The operating principle of the device is as follows: - the extinguishing fluid 50 is introduced inside the container 10 via the valve 12a until the predetermined operating pressure is reached; once said pressure is reached, the fluid 50 pushes against the flat member 23, overcoming the opposing force of the spring 25 and causing closure of the contact;

- the two terminals 22 which are accessible from the outside are connected (Fig. 12) to the respective wires Ia, Ib for connection to the electric power supply (not shown) of the box and to the input of the electric circuit contained inside a mounting/junction box 3 ;

- should a fire break out inside the box or should the conditions favouring the outbreak of a fire exist, the rapid increase in heat would cause opening of the container, resulting in the pressurised release of the extinguishing fluid precisely in the possible outbreak zone; - at the same time the drop in internal pressure is such that the pushing action of the spring 25 on the flat member 23 is no longer opposed, causing opening of the switch which interrupts in this way the power supply to the electric control panel; - thereby eliminating the cause of the outbreak.

Figs. 8 to 11 show a second example of embodiment of the device according to the invention.

In this configuration it is envisaged that the surface 110c of the container 110 which during use is situated in position opposite and above the possible fire source - represented by way of example in Fig. 12 as an electric control panel - is provided with openings 113 in the bottom side so as to connect the external environment with the inside of the container 110 containing an air chamber 150 perimetrally retained by two half-shells 110a, 110b of the container 110.

The air chamber also has an inlet mouth 151 connected to a one-way valve 11a for supplying the extinguishing fluid 50 which is introduced under pressure inside the said air chamber.

The switch 20, entirely similar to that described above, is in this case also arranged on one side of the container 110.

In this configuration, the introduction of the extinguishing fluid 50 inside the air chamber 150 causes expansion of said chamber which, swelling, occupies the available volume inside the container, coming into contact with the flat member 23 of the switch 20 which closes under the corresponding thrusting force.

The version described above has certain advantages associated with the fact that the thickness of the air chamber may be substantially less than that of the container 10, resulting in a notable increase in the speed of response of the device to the possible outbreak of a fire; this speed is furthermore increased by the presence of the openings 113 which allow a direct contact between heat source/flame and the balloon itself, accelerating breakage thereof and therefore extinguishing/elimination of the cause of the incipient fire.

Conveniently the geometry of the container 10,110 may assume the most varied forms and dimensions in relation to the final location of the said device, as for example illustrated in Fig. 12 where the device is applied to an electric wiring box 3 in a position above it, so that it is acted on by the heat/flame, and along the whole length and depth of the said box with which the device may be associated subsequently, in the case of ready existing boxes, or incorporated therein at the time of production.

In any case, the device according to the invention is able to cover a surface of suitable area arranged above the electrical apparatus which may become the source of a possible outbreak of fire.

It is considered moreover within the scope of the person skilled in the art to envisage means and arrangements for replacing the entire device and/or for replenishing the fluid in the case of use or a drop in the internal pressure.

It is therefore obvious how, with the device according to the invention, it is possible to achieve an improved and automatic capacity for eliminating the cause of outbreak of a fire, as well as an increased possibility of extinguishing a fire, said device moreover being able to be applied in any easy and low- cost manner to any type of apparatus, system or the like in which the possibility of a fire breaking out is envisaged. It is envisaged, moreover, that the device may be associated with means for visually signalling that action has been taken, which means are visible on the outside so as to allow the user to identify rapidly the deactivated zone; said means may be of the electric and/or mechanical type.

Claims

1. Device for extinguishing the outbreak of a fire, characterized in that it comprises a container (10; 110) which has, arranged inside it, at least one switch (20) which can be closed by an extinguishing fluid (50) under pressure, introduced inside the said container (10;110) .

2. Device according to Claim 1, characterized in that said container comprises at least one one-way valve (11,12) for introducing the fluid (50) inside the said container.

3. Device according to Claim 1, characterized in that said container (10;110) is made of thermoplastic material .

4. Device according to Claim 1, characterized in that said container (10,-110) has a low melting point.

5. Device according to Claim 3, characterized in that said switch (20) comprises an insulating body

(21) .

6. Device according to Claim 5, characterized in that said insulating body (21) is incorporated in one of the surfaces of the container.

7. Device according to Claim 3, characterized in that said switch comprises two contacts (22) which are accessible from the outside.

8. Device according to Claim 1, characterized in that said contacts (22) also have a conducting surface (22a) which is exposed towards the inside of the container (10;110) and is able to come into contact with respective means of the closing element (23) of the switch.

9. Device according to Claim 1, characterized in that the closing element of said switch consists of a flat member (23) comprising at least one pin (23a) projecting towards the contacts (22) against which it may be brought to bear.

10. Device according to Claim I₇ characterized in that said closing element can be actuated against the opposing action of at least one spring (25) arranged between the flat member (23) and the insulating body (21) .

11. Device according to Claim I₇ characterized in that said switch (20) is normally open.

12. Device according to Claim 1, characterized in that said flat member (23) is associated with an insulating element (23b) perimetrally arranged around the edge of the said flat member.

13. Device according to Claim 1, characterized in that said container (110) comprises an air chamber (150) inside it.

14. Device according to Claim 13, characterized in that said air chamber (150) is perimetrally constrained to the sides of the container (110) .

15. Device according to Claim 13, characterized in that said air chamber (150) is made of elastically deformable material .

16. Device according to Claim 13, characterized in that said air chamber (150) is made of thermoplastic material .

17. Device according to Claim 13, characterized in that said air chamber (150) is made of material with a low melting point.

18. Device according to Claim 13, characterized in that said air chamber (150) has at least one entry hole connected to a one-way supply valve.

19. Device according to Claim 13, characterized in that an extinguishing fluid under pressure (50) ^' is introduced inside said air chamber (150) .

20. Device according to Claim 12, characterized in that the deformation of the air chamber (150) following pressurised filling causes closing of the switch (20) .

21. Device according to Claim 12, characterized in that at least one surface (110c) of the container (110) has openings (113) for connecting the external environment with the air chamber.

22. Box containing electric devices (4) , characterized in that it comprises inside it a device for extinguishing the outbreak of fires according to Claim 1.

23. Box according to Claim 22, characterized in that said device is arranged above the electric devices.

24. Box according to Claim 22, characterized in that said device extends over at least two dimensions of the said box.

25. Box according to Claim 24, characterized in that at least one of said dimensions is the depthwise dimension.

26. Box according to Claim 22, characterized in that it is an electric junction box.

27. Box according to Claim 22, characterized in that it is an electric wiring box.

28. Box according to Claim 22, characterized in that the devices are supplied by means of a lead (2) connected to one of the two contacts of the switch (20) .

29. Box according to Claim 22, characterized in that the other of the two contacts of the switch (20) is connected to the mains power supply by means of an associated lead (1) .

30. Box according to Claim 22, characterized in that it comprises means for visually signalling deactivation of the said box, which are visible from the outside.

31. Box according to Claim 22, characterized in that said signalling means are of the electric type.

32. Box according to Claim 22, characterized in that said signalling means are of the mechanical type.