EP3009999A1 - Built-in linear smoke detector - Google Patents

Abstract

The invention relates to a smoke detection system comprising: a linear smoke detector for emitting a light beam and for detecting a reflected part of this light beam, this linear detector comprising a shell and passive and active components, and a retro-reflector arranged facing the linear detector to reflect the light beam. According to the invention, the passive and active components comprising at least one light beam emitter and a receiver, are inserted into the shell which is recessed into a wall.

Description

The present invention relates to a linear smoke detector to be disposed in a room, in particular on a wall, for detecting smoke in the event of the beginning of a fire. A linear detector is a beam emitter / receiver, generally infrared, which is reflected on a reflex reflector fixed on a remote wall. The collected beam back is detected and analyzed in order to deduce a presence or not of smoke.

The object of the present invention is a non-intrusive integration of the linear detector.

Another object of the invention is the production of a linear detector of great precision and high efficiency.

The invention also relates to a linear smoke detector difficult to detach when attached to a wall.

• un détecteur linéaire de fumée pour émettre un faisceau lumineux et détecter une partie réfléchie de ce faisceau lumineux, ce détecteur linéaire comprenant une coque et des composants passifs et actifs, et
• un catadioptre disposé face au détecteur linéaire pour réfléchir le faisceau lumineux.

At least one of the above-mentioned objectives is achieved with a smoke detection system comprising:

• a linear smoke detector for emitting a light beam and detecting a reflected portion of said light beam, said linear detector comprising a hull and passive and active components, and
• a retro-reflector arranged facing the linear detector to reflect the light beam.

According to the invention, the passive and active components comprising at least one light beam emitter and a receiver, are inserted into the shell which is recessed into a wall.

With the system according to the invention, it is expected to insert the passive and active components in the shell of the linear detector so that the shell can be almost or completely recessed, only the cover may or may not exceed the wall. This lid can also come flush with the wall.

By active component is meant an electrical component requiring a power supply. In contrast, a passive component is a non-active electrical component. Of course, the shell also includes mechanical parts and optical elements.

A built-in linear detector has the advantage of being difficult to detach from the wall, in particular by an unauthorized person.

Such a linear detector also has the advantage of being very aesthetic, which allows to provide a discreet installation in places with a strong aesthetic character.

• l'émetteur de faisceau lumineux accouplé à un collimateur,
• le récepteur accouplé à une lentille de Fresnel,
• une carte électronique dotée d'un microprocesseur pour la gestion de l'émetteur et du récepteur.

According to an advantageous characteristic of the invention, the linear detector may comprise:

• the light beam emitter coupled to a collimator,
• the receiver coupled to a Fresnel lens,
• an electronic card with a microprocessor for managing the transmitter and the receiver.

The invention is particularly remarkable, but not only, in that to allow embedding, the linear detector is miniaturized by reducing its thickness. The dimensions of the linear detector are now comparable or identical to standard dimensions of built-in electrical devices. In particular, the reduction in thickness is achieved by reducing the focal length on transmission and reception within the linear detector. Advantageously, the transmitter is associated with a transmitter and a low focal length collimator. At the reception, a Fresnel lens is associated with a photodetector (receiver). The components can be advantageously chosen so that the focal lengths are almost identical.

Preferably, the collimator may have a focal length less than or equal to 3.5 cm. Better still, this focal length may be less than or equal to 1.6cm. With such a dimensioning, it is possible to envisage a linear detector of small dimensions that can easily be embedded. This linear detector may have a thickness of substantially 6 cm.

According to an advantageous characteristic of the invention, the collimator may have at its output a divergence of width at half height less than or equal to 8 degrees. A collimator is used because it generally makes it possible to diffuse a beam of parallel rays with a reduced focal length. In smoke detection applications, the linear smoke detector may not be properly secured or may deviate slightly from the axis with time due to wall movements. In this case, having such a divergence of the beam coming out of the linear smoke detector can be considered as an advantage. The bright spot of the light beam thus obtained on the reflex reflector arranged at a distance has a certain width, which ensures permanently at least one overlap between this spot and the reflex reflector.

According to an advantageous characteristic of the invention, the transmitter can be integrated in the collimator so that all the beams of the transmitter are collected by the collimator. In this case, the collimator is a conical block having a cavity at the end of small section. The transmitter is intended to be housed in this cavity and to diffuse through the inside of the collimator. As a result, all the energy of the transmitter is transmitted via the collimator.

Advantageously, the transmitter comprises a LED said LED. This LED can be of the CMS type (surface-mounted component or SMD in English for "surface mounted device") disposed on the electronic board.

Preferably, the reflex reflector is placed on a transparent or translucent support so as to integrate it as much as possible into its environment, typically making it as less visible as possible with respect to the wall on which it is placed. With a built-in linear detector and a discrete reflector, the entire system can be easily installed without being overly intrusive.

The linear detector may comprise in the shell two conical insulators respectively around the emitter and receiver of the linear detector so as to independently isolate the transmit and receive beams in the shell. Each insulator is a conical wall, the weakest section being on the transmitter and receiver side respectively. These two insulators achieve a double isolation between the transmitter and the receiver. Indeed, even if all the beams of the transmitter are collected by the collimator, a tiny part can escape by parasitic reflections and can reach the receiver directly without being reflected by the reflector. The dimensions of these two insulators are compatible with the compactness of the linear detector.

Advantageously, the shell comprises a filter centered on the wavelength of an infrared beam used in smoke detection. This filter is for example a polycarbonate treated with a dye so as to block the visible light.

• La figure 1 est une vue schématique d'un système selon l'invention comprenant un détecteur linéaire encastré face à un catadioptre,
• La figure 2 est une vue schématique très simplifiée d'un catadioptre selon l'invention,
• La figure 3 est une vue schématique très simplifiée de quelques composants internes du détecteur linéaire encastré,
• La figure 4 est une vue schématique simplifiée illustrant la base d'un collimateur,
• Les figures 5a et 5b sont des vues schématiques en perspective et en coupe de la coque, et
• Les figures 6a et 6b illustrent une pièce mécanique intégrant deux isolateurs.

Other advantages and features of the invention will appear on examining the detailed description of an embodiment which is in no way limitative, and the appended drawings, in which:

• The figure 1 is a schematic view of a system according to the invention comprising a linear detector embedded in front of a retro-reflector,
• The figure 2 is a simplified schematic view of a retro-reflector according to the invention,
• The figure 3 is a very simplified schematic view of some internal components of the built-in linear detector,
• The figure 4 is a simplified schematic view illustrating the base of a collimator,
• The Figures 5a and 5b are schematic views in perspective and in section of the hull, and
• The Figures 6a and 6b illustrate a mechanical part incorporating two insulators.

On the figure 1 we see two walls 1 and 2, including two walls of a building, facing each other. These two walls 1 and 2 can constitute two walls of an entrance of a luxury building for which one wishes a maximum discretion. We want the walls to have a beautiful aesthetic appearance. To do this, it provides a least intrusive installation of a smoke detection system according to the invention. This system comprises a linear detector 3 embedded in the wall 1 so that the upper cover of this sensor is flush with the wall 1 or overhangs this wall of negligible thickness, that is to say a thickness that can hardly be perceived at distance, typically less than 8mm.

For those skilled in the art, a linear detector is a device clearly identified and whose function is the emission and reception of a beam of light. The intensity of the light beam received allows determine whether the atmosphere traversed by the light beam comprises smoke or not.

The linear detector 3 according to the invention emits a light beam towards a reflex reflector 4 disposed on the wall 2 opposite.

Advantageously, the reflector 4 is a translucent blade placed on a support 5 made of transparent plastic or with a color identical to the color of the wall 2. figure 2 , we see the reflex reflector 4 inserted into the support 5, the latter being in the form of a box with a central opening 6 at the rear. Preferably, the support 5 is transparent and fixed to the wall by not very visible fixing means such for example translucent glue or screws of the same color as the wall. The reflector 4 is designed and positioned to return any beam of light to the source thereof.

Such a reflex reflector can be carefully placed on a wall in a way that is almost non-intrusive, that is to say that its integration into the environment is not aggressive, it is not very visible.

Similarly, the linear detector is partially or completely embedded in the wall so as to be inconspicuous. The present invention is particularly remarkable in that it incorporates in a thin shell all the passive and active components necessary for the emission and reception of a light beam. Said thickness can be defined as the height of the linear detector, typically the height of the shell, measured along the optical axis (path of the light beam). The fact of minimizing this thickness while maintaining a diameter in standard dimensions, allows easy installation of the linear detector, in particular flush with the wall.

For the reduction of the thickness, the inventors have been confronted with a significant problem insofar as the linear detector must have optimum efficiency irrespective of its size. Indeed, the internal components of the linear detector must remain very efficient. To reduce the thickness, the solution was to reduce the focal length of the optical components to the emission and reception of the light beam. This solution is concretized advantageously with the combination of components as illustrated on the figure 3 . There is a shell 7 plastic cylindrical with ribs and side pockets as we will see on the figure 5a . This shell has openings on its base or on one side for the passage of power cables and signal transmission. There is an electronic card 8 which is powered by cables from a power supply network via the wall, but it can also be powered by a removable battery disposed in the shell. Very schematically, there is a transmitter 9 for emitting a light beam towards the catadiopter 4 and a receiver 10 for receiving the light beam reflected by the reflector 4.

The transmitter 9 is advantageously a light emitting diode (LED or LED in the English language for Light Emitting Diode) type CMS fixed for example directly on the electronic card 8. The characteristics of this LED can be a wavelength centered at 940 nm , a direct supply current of less than or equal to 2 A, an angular divergence of the emitted flux of width at half height less than or equal to 160 degrees. It may be a diode emitting a diverging beam of light. Advantageously, all the beam coming out of the transmitter 9 is picked up by a collimator 11. The purpose of the collimator 11 is to try to make the constituent beams of said light beam parallel. To do this, the collimator may have a particularly flat base and be placed above the transmitter so as to capture the maximum beams emitted by the transmitter. This collimator can be directly in contact with the transmitter or via a suitable fastening means. In the example of the figure 3 the collimator 11 comprises on its base a recess or box 12 of complementary shape to the shape of the emitter. The function of the box is to receive with or without contact the transmitter when the collimator is placed on the transmitter 9. The box 12 is thus completely cover the transmitter so that the beams leaving the transmitter are captured by the collimator 11. On the figure 4 , we see the base of the collimator 11. It distinguishes the box 12 dug in the collimator and having for example a parallelepiped shape. Other forms may be used in particular to conform to the shape of the transmitter, but not only.

According to the invention, it is possible for example to use a reference collimator LLC05N (from Gaggione®), with a maximum diameter of 32.5 mm; a height of less than 16 mm. The collimator may have as output a divergence of width at half height less than or equal to 8 degrees.

On the front face of the collimator, that is to say the exit face of the light beam 13, there is a convex peripheral zone 14 all around a central zone 15 bulging outwards. The outer face thus has a profile adapted to collimate as much as possible the light beam 13. However, one can choose a collimator having characteristics that do not allow a perfect collimation. Indeed, one may wish to have a slight divergence of the light beam 13 so that the spot of the latter on the opposite wall is large enough to cover at least a portion of the reflector at the time of installation and when both walls undergo a slight shift relative to each other over time. By way of example, it is possible to provide a divergence of the light beam 13 of width at half height less than or equal to 8 degrees.

• diamètre de 32.5 mm,
• distance focale de 14 mm (<16mm),
• épaisseur de 1.55mm,
• des sillons sont définis sur la lentille avec une épaisseur constante et un pas variable ce qui minimise les discontinuités et maximise la transmission lumineuse.

The reflex reflector 4 serves to return a portion of the light beam to the linear detector 3 so that the receiver 10 captures this feedback signal for analysis. The return light beam 16 is first captured by a Fresnel lens 17 whose function is to converge this light beam towards the receiver 10. A Fresnel lens is preferably used because it allows a short focal length for a large diameter. . It is for example a plano-convex lens cut out of concentric annular sections. The cut made in the lens can significantly reduce its weight compared to a standard planoconvex lens and significantly reduce its thickness. In this case, if a plano-convex lens with such a focal length was used, the lens would have the thickness of a half table tennis ball. Advantageously, the focal length of the Fresnel lens is identical or very close to the focal length of the collimator. "Close" means a distance of less than or equal to 50 percent. In any case, the Fresnel lens is also disposed inside the shell which has a reduced thickness, for example 6 cm. The characteristics of the Fresnel lens can be as follows:

• diameter of 32.5 mm,
• focal length of 14 mm (<16mm),
• 1.55mm thick,
• furrows are defined on the lens with a constant thickness and a variable pitch which minimizes discontinuities and maximizes light transmission.

On the electronic card 8 there is also a microprocessor 20 for managing the transmitter, the receiver and other active components of the linear detector.

Preferably, to isolate the light beams on transmission and reception, there are two insulators 18 and 19 of conical shape respectively around the transmitter 9 and the receiver 10. Each insulator is flared towards the exit of the hull. Both insulators can be connected together to form a single component. They can be black in color and plastic. The height of each isolator may be determined to be equal to or slightly greater than the focal length of the collimator or Fresnel lens.

At the outlet of the shell 7 there is a filter 21 for passing the operating light beam of the linear detector and blocking the ambient light. For example, the light beam 13 (and 16) is an infrared signal that can pass through the filter 21 in both directions.

The shell 7 is illustrated on the Figures 5a and 5b in more detail. There are many notches and protuberances for fixing the shell in the wall and for fixing internal components in the shell. The overall outer shape is identical to a standard shell type hull form for electrical equipment such as switch or socket. The shell has an upper flange 22 intended to serve as a stop against the outer face of the wall. On the figure 5b , we see a sectional view of the shell 7 with the inscription of the dimensions such as the height of 6cm and the diameter of about 10cm. The diameter of the rim is about 11cm.

On the figure 6a , we see in detail a mechanical part 23 plastic to insert into the shell. This mechanical part is represented in a radial section on the figure 6b . It comprises the two insulators 18 and 19 and fastening means for a highly accurate arrangement within the shell 7. The mechanical part 23 and shaped to receive the Fresnel lens and the collimator in the insulators. Shims are provided for the Fresnel lens to be at a predetermined distance from the receiver. The filter 21 is intended to be fixed on the mechanical part 23 by means of clips.

Of course, the invention is not limited to the examples that have just been described and many adjustments can be made to these examples without departing from the scope of the invention. In the example described, there is a transmitter and a receiver, but we can consider one or more transmitter (s) associated with one or more receiver (s).

The receiver is disposed on the same electronic card as the transmitter, but it can also be arranged on a different electronic card, not necessarily next to or on the same plane as the transmitter.

The dimensions indicated in the figures are given for information only. Other dimensions can be envisaged.

The linear detector according to the invention can work with any type of reflex reflector technically designed to send light back to the transmitter. Preferably this reflector is still transparent or translucent so as to remain difficult to detect by malicious people.

Ideally, an infrared beam is used, but other wavelengths may be considered. The filter placed on the shell must be adapted to the wavelength used.

Claims (11)

Smoke detection system comprising: a linear smoke detector for emitting a light beam and for detecting a reflected part of this light beam, this linear detector comprising a shell and passive and active components, and a retro-reflector arranged facing the linear detector to reflect the light beam,
characterized in that the passive and active components comprising at least one light beam emitter and a receiver are inserted into the shell which is recessed into a wall. System according to claim 1, characterized in that the linear detector comprises: said light beam emitter coupled to a collimator, said receiver coupled to a Fresnel lens, an electronic card equipped with a microprocessor for managing the transmitter and the receiver. System according to claim 1 or 2, characterized in that the collimator has a focal length less than or equal to 3.5 cm. System according to claim 3, characterized in that the focal length is less than or equal to 1.6 cm. System according to any one of Claims 2 to 4, characterized in that the collimator has at its output a divergence of width at half height less than or equal to 8 degrees. System according to any one of claims 2 to 5, characterized in that the transmitter is integrated in the collimator so that all the beams of the transmitter are collected by the collimator. System according to any one of claims 2 to 6, characterized in that the transmitter comprises a LED said LED. System according to any one of the preceding claims, characterized in that the linear detector has a thickness of substantially 6 cm. System according to any one of the preceding claims, characterized in that the retro-reflector is placed on a transparent or translucent support. System according to any one of the preceding claims, characterized in that the linear detector comprises in the shell two conical insulators respectively around a transmitter and a receiver of the linear detector so as to isolate the transmit and receive beams. in the hull. System according to any one of the preceding claims, characterized in that the shell comprises a filter centered on the wavelength of an infrared beam used in smoke detection.

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