Combination of an object for protecting and a fire-fighting device, and method for targeted protection

Field of the invention

The invention relates to a combination of an object for protecting and a fire-fighting device, comprising a spray nozzle with an outflow opening, a heat-sensitive element and a curved surface. The invention also relates to a method for targeted protection of an object by means of such a fire-fighting device.

Background of the invention

Fixed fire-fighting devices are known such as sprinklers and spray extinguishing devices with automatically operating sprinkler heads, wherein each sprinkler head is generally provided with a heat-sensitive element, for instance a melting switch, a breakable bulb or a thermally expandable element. The sprinkler heads can be arranged in a ceiling, a wall or a floor. In the case of a fire heat will be transported by means of convection to the heat-sensitive element, after which the element, above a determined temperature, will melt, break or deform. A sealing plug can here be released or a valve can open, whereupon fire-extinguishing material will be sprayed into the space in question, see for instance US 6123153. EP1413333 describes a sprinkling head for fire fighting systems with a curved/parabolic surface for directing radiant heat/IR radiation at a heat-sensitive element. US 1636444 describes a sprinkler system wherein the sprinkler head is automatically closed again once a fire has been extinguished, this in order to prevent unnecessary water damage. These devices and systems are however not suitable, or less suitable, for targeted protection of a specific object.

The spray pattern of a sprinkler head will generally be roughly circular, wherein the fire- extinguishing material is directed within a limited solid angle so that the sprinkler head covers a number of square metres. If a determined spray pattern is desired, a sprinkler head can be provided with an obstructor and/or a deflector which blocks the flow of fire-extinguishing material in a determined direction and/or urges it in a determined direction, see for instance WO02/00302, US3880239, DE19539991, FR2652763, US 2005/0067171, US 6098718,

US 2002/0056763, US 2003/0111237, CA 2327572 and US 2003/0222155. These devices and systems are however not suitable, or less suitable, for targeted spraying of a specific object.

Known fire-fighting devices are therefore not suitable or less suitable for targeted protection of a specific object where targeted surveillance and targeted extinguishing are desired. There is therefore a need for a technical solution for targeted protection of a specific object from fire. The invention has for its object to meet this need.

Summary of the invention

The invention provides for this purpose a combination of an object for protecting and a fire- fighting device, comprising a spray nozzle with an outflow opening, a heat-sensitive element and a curved surface, characterized in that the object for protecting, the heat-sensitive element and the curved surface are placed relative to each other and the curved surface is of a form such that radiant heat from the object for protecting is directed selectively onto the heat- sensitive element by means of the curved surface. Selectively is understood to mean that substantially only radiant heat from the object for protecting is directed onto the heat-sensitive element, while other radiant heat from the environment or other objects will substantially not reach the heat-sensitive element. The heat-sensitive element can for instance be a known melting switch, breakable bulb or thermally expandable element which serves as means for releasing the spray nozzle. If according to a method provided by the invention the object for protecting, the heat-sensitive element and the curved surface are now placed relative to each other and the curved surface is given a form such that radiant heat from the object for protecting is directed selectively onto the heat-sensitive element by means of the curved surface, substantially only radiant heat from the object for protecting will reach the heat- sensitive element. At least one plane section of the curved surface can take substantially the form of a part of a parabola. The curved surface can herein substantially take the form of a part of a paraboloid. The focus of the relevant parabola is here preferably situated at least in the vicinity of the heat-sensitive element, and preferably falls inside it. Radiant heat from the object for protecting can thus be directed well and selectively onto the heat-sensitive element. It will be apparent to a skilled person that, by varying and selecting the mutual placing of the object for protecting, the heat-sensitive element and the fonn of the curved surface, the 'field

of vision' of the heat-sensitive element can be adapted to the position, size and form of the object for protecting. A specific object can thus be guarded in targeted manner.

The object for protecting, the outflow opening and the curved surface can here also be placed relative to each other and the curved surface also be of a form such that fire-extinguishing material leaving the outflow opening is directed selectively onto the object for protecting by means of the curved surface. Fire-extinguishing material leaving the outflow opening will then strike substantially only the object. The object can thus be sprayed with extinguishing material in targeted manner. It will again be apparent to a skilled person that, by varying and selecting the mutual placing of the object for protecting, the outflow opening and the form of the curved surface, the spray pattern of the spray nozzle can be adapted to the position, size and form of the object for protecting. The 'field of vision' of the heat-sensitive element and the spray pattern of the spray nozzle will now substantially overlap each other. This is surprisingly found to be possible. The object can therefore be protected in targeted manner.

Short description of the figures

The invention is elucidated hereinbelow with reference to the figures, in which: figure 1 shows a longitudinal section of a first spray nozzle forming part of a first exemplary embodiment of a combination according to the invention; figure 2 shows a longitudinal section of a second spray nozzle forming part of a second exemplary embodiment of a combination according to the invention; and figure 3 shows schematically the 'field of vision' and the spray pattern associated with the first exemplary embodiment.

Exemplary embodiments of a spray nozzle and a method according to the invention

A first spray nozzle (1), see figure 1, comprises an outflow opening (10) for fire-extinguishing material and is provided with a heat-sensitive element (1 1), in this case a normal glass bulb filled with a thermally expandable medium. Heat-sensitive element (11) serves as release means for spray nozzle (1) and holds in place a sealing plug (13) sealing outflow opening (10). The heat-sensitive element can optionally also be placed elsewhere, clear of the spray

nozzle. The first spray nozzle (1) can for instance be mounted on a wall and connected by means of an inlet opening (15) to a conduit (not shown) for the supply of extinguishing material, or for instance be mounted on a stand-alone fire extinguisher. Spray nozzle (1) is also provided with a curved surface (12) of a form and placed relative to heat-sensitive element (11) such that radiant heat incident upon curved surface (12) from a first solid angle (3), see figure 3, is directed for at least the greater part at heat-sensitive element (11). The curved surface can optionally also be placed elsewhere, clear of the spray nozzle. According to a usual definition, a solid angle is a part of the space formed by a point and a (randomly formed) surface in space, wherein in the present case the point lies at the position of the spray nozzle. Curved surface (12) has in this case the form of a part of a paraboloid and heat-sensitive element (11) is placed in the focus thereof. More generally, the form and the placing of the curved surface can be adapted to a desired orientation, size and form of the first solid angle, and a desired 'field of vision' of the heat-sensitive element can hereby be obtained, adapted to the position, size and form of the object for protecting.

Curved surface (12) is also of a form and placed relative to outflow opening (10) such that fire- extinguishing material leaving outflow opening (10) is directed for at least a significant part within a second solid angle (4) by means of curved surface (12), see figure 3. More generally, the form and the placing of the curved surface can once again be adapted to a desired orientation, size and form of the second solid angle, and a desired spray pattern of the spray nozzle can hereby be obtained, adapted to the position, size and form of the object for protecting.

Curved surface (12) is also of a form and placed such that the first solid angle (3) and the second solid angle (4) coincide to a significant extent. This is surprisingly found to be possible, so that the same surface can be used to direct the radiant heat and to direct the fire- extinguishing material. If an object for protecting (5), see figure 3, is now located within the first solid angle (3) and the second solid angle (4), radiant heat from the object for protecting (5) will be concentrated on heat-sensitive element (11). In the case of fire or heating of the object for protecting (5) the heat-sensitive element (11) will be heated and, above a determined temperature, break. Sealing plug (13) is herein released, whereupon fire-extinguishing material leaving outflow opening (10) will be directed substantially onto the object for protecting (5) by

means of curved surface (12). The object for protecting (5) can thus be protected in targeted manner and sprayed with extinguishing material in targeted manner.

A second spray nozzle (2) according to the invention, see figure 2, likewise comprises an outflow opening (10) for fire-extinguishing material and is likewise provided with a heat- sensitive element (11). Second spray nozzle (2) is again provided with a curved surface (12) so that radiant heat is directed onto heat-sensitive element (11) from a determined solid angle. Here however, outflow opening (10) is closed by a closing valve (14) which is opened when heat-sensitive element (11) breaks and then allows passage of extinguishing material to an outlet (16). An object for protecting can thus be protected in targeted manner and, albeit in less targeted manner, be sprayed with extinguishing material, in the given example directly from outlet (16). The outlet can here optionally also form part of for instance a stand-alone spray nozzle.

It will be apparent that the invention is by no means limited to the given exemplary embodiments, but that many more variants are possible within the scope of the invention.