ES2660499T3 - Wall mounted visual alarm device - Google Patents

Abstract

A visual alarm device configured to be mounted on a mounting wall and illuminate a parallelepipedic shape with a flash light having a minimum light intensity, the visual alarm device comprising: a housing (1, 3) configured to be mounted on the mounting wall; a plurality of light emitting devices (13) provided in the housing (1, 3); the plurality of light emitting devices (13) consisting of five LEDs substantially mounted in a row on a printed circuit board (15), the outer LEDs of the row being provided in dedicated arms (19) and inclined at an angle of substantially 40º with respect to the mounting wall, when the visual alarm device is mounted on the mounting wall; a reflector body (17) configured to direct the light emitted by the light emitting devices (13) into four predetermined fields partially overlapped by means of individual faceted cavities, the reflector body (17) comprising a central reflector cavity and cavities left and right reflector; These fields comprise: a first field that covers a front wall and a distant floor of the parallelepipedic shape and that is illuminated by the direct light of the three central LEDs and the light reflected by the central cavity; a second field that covers the left side wall of the parallelepipedic form that is illuminated by the direct light of the left side LED and the light reflected from the left cavity; a third field that covers the wall on the right side of the parallelepipedic form that is illuminated by the direct light of the LED on the right side and the light reflected by the right cavity; and a fourth field that covers the area of the near ground around and below the visual alarm device of the parallelepipedic form illuminated solely by reflections from an upper central part of the central reflector cavity.

Description

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DESCRIPTION

Wall mounted visual alarm device

The present invention relates to a visual alarm device (VAD) for informing people within a building about dangerous situations or events.

European standard EN54-23 specifies the requirements, test methods and performance criteria for visual alarm devices in a fixed installation intended to signal a visual warning of a fire between the fire detection and fire alarm system and occupants of a building. The visual alarm devices can be pulsating or intermittent visual alarm devices.

Under this standard, VADs can be classified into three categories, namely ceiling mounted devices, wall mounted devices and an open class category. Each of these categories has specific objectives for light distribution patterns. The devices must guarantee a coverage volume where a required illumination of 0.4 lux or 0.4 lm / m2 is achieved.

The flash speed of a VAD must be between 0.5 Hz and 2 Hz and must emit a red or white flash.

The wall-mounted VAD will be effective in a wide range of applications. The manufacturer shall indicate a mounting height, which is a minimum of 2.4 m, followed by the width of a square room on which the VAD will provide coverage.

Therefore, the specification code with a VAD suitable for a wall application could mark W-2.4-6, that is, mounted at a height of 2.4 m, the VAD will cover a room of 36 m2. Therefore, the VAD will be required to cover the volume below its mounting height. In other words, a wall-mounted Vxy of the Wxy type is needed to illuminate a parallelepiped of a height xy with a basic square area having an edge length and, to achieve a minimum illuminance within this parallelepiped of 0.4 lux .

To meet the requirements of BS EN54-23 and cover a practical room size found in most situations, VADs must have higher light output levels than those generally used in today's market, which leads to a considerable increase in current consumption due to the use of higher output devices or a greater number of less powerful units. Consequently, the design of the light distribution became more relevant.

In order to produce the greatest coverage for a given total light output (or input power), then highly efficient shaping optics are required. A perfect optic would uniformly illuminate the faces of the parallelepiped, however, it should be taken into account that the effective output of a candle in any direction in the parallelepiped increases with the square of the distance, making the conformation optics extremely difficult to design with good effectiveness.

Also, for a cost-effective design, an audio alarm or sound alarm would need to be incorporated in the device. The coverage of this acoustic receiver is dictated mainly by its sound pressure level (SPL) and the level of background noise in a building. In general, a wall-mounted acoustic receiver is expected to have a rating that exceeds 100 dB (A) at 1 m and is suitable for a relatively large coverage area in most applications. This means that in a combined device, if the coverage of the VAD cannot match the coverage of the acoustic receiver in any reasonable measure, then a cost-effective solution cannot be made. It should be noted that the cost of installing alarm devices is often many times greater than the actual unit cost of any additional device. EP 2 858 047 A1 presented before the present application, but published below, shows a main configuration of a visual alarm device comprising a corresponding control circuit to optimize the output of a plurality of LEDs.

US 2014/0268753 discloses an indicator set for a visual life safety alarm that includes a hollow reflector ring, generally truncated, having an angled wall. The reflector ring is mounted in a visual life safety alarm housing at a first end. A first plurality of light devices is mounted in the housing within a first opening of the first end of the reflector ring. The light of the first plurality of light devices is configured to emit in a generally forward direction. A second plurality of light devices is mounted in the housing near the angled wall of the reflector ring, opposite the first plurality of light devices. The light of the second plurality of light devices is configured to be reflected from the angled wall in a generally angled direction from the visual security alarm.

US 2012/0038479 A1 discloses a lighting device that includes a light source. The lighting device is arranged to be mounted on a wall at a mounting height with respect to a floor. The lighting device is arranged, in use, to illuminate a predetermined area of the floor, in which: the mounting height is between 0.4 and 0.8 meters from the floor; and the predetermined area of the ground has a shape

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substantial rectangular. The lighting device is designed as an escape route or panic lighting.

The aim of the present invention is to provide a wall mounted visual alarm device having an improved lighting system.

According to the present invention, the foregoing objective is achieved by a visual alarm device according to claim 1. The dependent claims are directed to different advantageous aspects of the invention.

In the following preferred embodiments of the invention, they will be described with reference to the drawings, which show:

Figure 1 shows an exploded view of a wall mounted VAD; Figure 2 shows in more detail the optical elements of the VAD of Figure 1; and Figure 3 is a perspective view of the VAD of Figure 1.

Preferred embodiments of the invention will be described based on the preceding figures.

Figure 1 shows an exploded view of a combined audio and visual alarm device configured to be mounted on a wall.

This VAD comprises a mounting box 1 and an external horn 3 that together form a housing. The housing of this embodiment further comprises a horn cup or cover 5.

As can be seen in Figure 2 inside the housing, a printed circuit board (pcb) 15 is provided.

A piezoelectric sound element 11 and a plurality of LED 13 are provided within the housing.

Although not shown in Figure 1, the alarm device is configured to connect to a bus with two wires to supply power and control signals to the alarm device. Instead, different bus configurations can be used, for example, those that have dedicated lines for power supply and control signals.

Figure 2 shows in more detail the optical components of the VAD of Figure 1.

The VAD of this example comprises five LEDs 13 in total. Two of them are fixed on raised tabs or arms 19. In addition, a reflector 17 cooperates with the LEDs 13 to guide the light emitted from the LEDs 13 in the desired directions.

The VAD of the preferred embodiment is equipped with five LEDs 13 and the corresponding optics.

As mentioned above, the VAD of Figure 1 and Figure 2 is designed as a wall mounted VAD.

The LEDs 13 in the VAD will be operated in case of an alarm or for testing purposes to emit light in the form of pulses or flashes.

The luminous intensity of the pulsed light is different compared to the intensity of the non-pulsed light due to the behavior of the human eye. The so-called effective intensity Ieff of pulsed light, expressed in candlelight, can be determined with the following equation, the Blondel-Rey equation:

image 1

where "I (t)" is the instantaneous intensity in the candle as a function of time, "a" is the constant of Blondel-Rey and "t2-t1" is the duration of the pulse (seconds).

Normally, the maximum effective intensity value is obtained when t2 and t1 are chosen so that the effective intensity is equal to the instantaneous intensity at t2 and t1.

From the Blondel-Rey equation, it is clear that the effective intensity depends on the duration of the pulse. The average power also depends on the flash speed, which is not examined in the Blondel-Rey equation.

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For rectangular or square pulses, the above equation is reduced to

image2

with steady state intensity I0 and pulse duration At.

An increase in pulse duration leads to an increase in effective intensity. The behavior is not linear.

The Blondel-Rey factor corresponds to the relationship between the effective intensity and the steady state intensity. Describe how much more light intensity in a pulse is needed to reach the steady state intensity of the un pulsed light.

As an example, for a pulse duration of 50 ms, the effective intensity is only about 20% of the steady state intensity. The luminous intensity of the pulse must be five times greater to reach the steady state intensity. Consequently, five times more pulse power is needed.

The average power will always increase with increasing pulse duration, since doubling the pulse duration does not mean doubling the effective intensity or halving the pulse power.

To maximize the efficiency of a wall-mounted VAD, a reflector design has been chosen to closely form a parallelepipedic shape.

The reflector 17 has a characteristically sharp cut for the rays that fall outside the required parallelepipedic illumination fields. The reflector 17 is mounted under a sealed optical cover 5. This cover 5 is a simple transparent optical cover, the shape of which also forms part of a sound horn. This simple cover 5 has only a small optical influence at certain lightning angles. Since the small influence of the cover 5 can be previously compensated by the reflector 17, it does not need to be discussed in detail.

LEDs 13 have been used in the design with 3 LEDs facing forward in a central reflector cavity and 2 LED "arms" mounted in the left and right reflector cavities. The 2 "arms" LED 19 have an angle of +/- 40 degrees using a PCB design that uses the fiberglass material in torsion, so there is no stress fracture.

This results in a robust and low-cost conventional PCB 15, in which the LEDs can be adjusted without the PCB 15 having to have a special support during the placement of the surface mount component. The 'arms' 19 of the PCB are then folded at an angle slightly larger than that required, so that a permanent angle remains after it has relaxed, but is slightly smaller than the final 40 degrees. This ensures that a small cantilever force will be exerted by twisting the PCB 15 in the final assembly, that is, it will be forced at the correct angle by the moldings.

Note that in the final position in the moldings, the LEDs 13 in the "arms" 19 will raise the origin of the beam above the level of the opaque main horn molding for the acoustic receiver.

The optical concept used by the VAD works by causing the reflector to break the form of parallelepipedic illumination required in 4 semi-superimposed fields. Each field is optimized for uniform illumination in separate parts of the cuboid using the LED or LED 13 in each individual faceted cavity. The combined composite lighting then forms the desired overall shape. The illuminated fields are listed below: The areas of the front wall and the far floor are illuminated by the central cavity of the reflector using the 3 central LEDs using direct and reflected light.

The wall on the left side is illuminated by the "arm" 19 on the left side and the cavity 17 on the left side of the reflector using direct and reflected light.

The wall on the right side is illuminated by the "arm" 19 of LED on the right side and the cavity on the right side of the reflector 17 using direct and reflected light.

The area of the nearby ground, that is, the area around and below the VAD is illuminated only by reflections from the upper central part of the central reflector cavity, raising the origin of the apparent beam above the molding of the main horn.

This design implies that there will be a relatively greater light output or an effective candle level in the superimposed limits of the illuminated fields.

This overlay is designed to occur at the edges of the parallelepiped that have the longest travel lengths of the VAD and, therefore, require relatively higher illumination. Note that the

Higher lighting will occur in the lower corners of the front wall.

Ideally, the reflector 17 would be a dielectric mirror that utilizes plasma coating layers improved and optimized to work in the visual spectrum or at least adapted to the required VAD colors.

5 Alternatively, a low-cost metallized plastic part would be suitable for reflector 17.

The reflector of the embodiment shown is formed by physical deposition of aluminum vapor (PVD) on a 2-part plastic molding. This process evaporates pure aluminum in a vacuum chamber. Although the reflectivity of aluminum is not as good as that of silver at the required operating wavelengths, it is low cost and inherently forms a very thin transparent protective barrier if exposed to the production atmosphere for a long time before adjusting it in a sealed cover molding.

Since the complete VAD using the reflector 17 forms a very efficient parallelepipedic form, this allows the greatest coverage volume for the least amount of power.

The efficiency of the reflector also has a benefit for the LEDs 13 and the drive circuit, since it allows the LEDs 13 to be operated at a shorter pulse duration and a lower peak current that improves the efficiency and reliability of the design. general.

In addition, it also benefits from the fire alarm system that provides the power for the VAD 13, so that more VADs are possible for any fire alarm circuit and the voltage drops in the cables are reduced.

Claims (4)

5 10 fifteen twenty 25 30 35 40 1. A visual alarm device configured to be mounted on a mounting wall and illuminate a parallelepipedic shape with a flash light having a minimum light intensity, the visual alarm device comprising: a housing (1, 3) configured to be mounted on the mounting wall; a plurality of light emitting devices (13) provided in the housing (1, 3); the plurality of light emitting devices (13) consisting of five LEDs substantially mounted in a row on a printed circuit board (15), the outer LEDs of the row being provided in dedicated arms (19) and inclined at an angle of substantially 40 ° with respect to the mounting wall, when the visual alarm device is mounted on the mounting wall; a reflector body (17) configured to direct the light emitted by the light emitting devices (13) into four predetermined fields partially overlapped by means of individual faceted cavities, the reflector body (17) comprising a central reflector cavity and cavities left and right reflector; These fields include: a first field that covers a front wall and a distant floor of the parallelepipedic form and that is illuminated by the direct light of the three central LEDs and the light reflected by the central cavity; a second field that covers the left side wall of the parallelepipedic shape that is illuminated by the direct light of the left side LED and the light reflected from the left cavity; a third field that covers the wall on the right side of the parallelepipedic form that is illuminated by the direct light of the LED on the right side and the light reflected by the right cavity; Y a fourth field that covers the area of the near ground around and below the visual alarm device of the parallelepipedic form illuminated solely by reflections from an upper central part of the central reflector cavity. 2. The visual alarm device according to claim 1, wherein the reflector body comprises a plurality of reflective surfaces that are covered by a metal layer, preferably a layer A1 formed by physical deposition of aluminum vapor. 3. The visual alarm device according to claim 2, wherein the reflector body (17) is a dielectric mirror that utilizes improved plasma coating layers, optimized to operate in the visual spectrum or match the required device colors visual alarm 4. The visual alarm device according to any one of claims 1 to 3, wherein the four fields have respective overlaps at the edges of the parallelepipedic form so that the most intense illumination of all will take place in the lower corners of the wall frontal.