SE541103C2 - ILLUMINATOR - Google Patents

Abstract

The invention relates to a device (7a-b) for illuminating particles in the air in a drawing space (1). The device has a line laser (7b) which emits light in a narrow light layer. Air in the drawing room is drawn out of the room through a perforated wall (8) and the device (7a-b) for lighting emits a light layer which extends parallel to and immediately adjacent to the front of the perforated wall. The light in the narrow light layer is directed straight downwards. The particle flow through the perforations gives an indication of the particle density in the immediate area and the particle lighting gives an increased visual contrast effect so that an operator gets an indication of the particle density.

Description

Lighting device The present invention relates to a lighting device according to the preamble of the independent claim.

In particular, it relates to such a lighting device intended to illuminate particles in the air.

Background of the Invention The particle concentration in the air varies greatly and should in many contexts be controlled and elevated particle concentrations may be inappropriate or directly dangerous. Substances in particulate form can, if sufficient, have toxic effects, cause allergies or even become flammable or explosive, so a simple visual indication of particle density would be desirable. Expensive particle density meters are available, but a simpler solution would be advantageous.

An object of the invention is therefore to provide a lighting device which gives a visual indication of particle density in the air.

These and other objects are achieved by a lighting device according to the characterizing parts of the independent claim.

Summary of the invention The invention relates to a device 7a-b for illuminating particles in the air in a drawing room 1.

The device comprises at least one line laser 7b which emits light in a narrow light layer. Air in the drawing space is drawn out of the space through at least one perforated wall 8 and the device 7a-b for lighting emits a light layer which extends substantially parallel to and immediately adjacent the front of the perforated wall. The light in the narrow light layer is directed straight down.

The particle flow through the perforations gives an indication of the particle density in the immediate area and the particle lighting advantageously gives an increased visual contrast effect so that an operator gets an indication of the particle density.

In advantageous embodiments, the particle lighting emits light that is short-wave or has a color that is complementary to the color of the prevailing other lighting.

Brief description of the figures Fig. 1 shows a drawing room with particle lighting according to a first embodiment Fig. 2 shows part of the first embodiment in greater detail Fig. 3 shows a second embodiment of the particle lighting Fig. 4 shows a third embodiment of the particle lighting Fig. 5 shows a fourth embodiment of the particle lighting Fig. 6 shows a fifth embodiment of the particle lighting Description of preferred embodiments A drawing room 1 is a device similar to a drawing cabinet, but so large that an operator can work inside the drawing room. Traction is used in the handling of dangerous, contagious or irritating substances that emit gases or particles that must be removed from the operator. An air stream is continuously moving through the drawing space to remove particles and gases. In order to make it clear to an operator that particles are indeed removed and for the operator to be able to take action if the particle concentrations are raised above an acceptable level, it may be advantageous to locally illuminate the particles in the particle flow. Even what from a more common perspective would be perceived as clean air that is apparently completely free of particles, contains particles and is suitably illuminated, these can be seen with the naked eye.

Fig. 1 shows a drawing room 1 with particle lighting 7a according to a first embodiment. The drawing space consists of a rectangular block-shaped space which is divided into two parts by an inner wall 8. The larger part of the drawing space 1 consists of an operator space 2 and the smaller part consists of a fan and filter space 3. In the fan and filter space 3 there is often a fan and filters are provided, where the fan draws air through perforations 5 in the inner wall, further through a filter and the purified air is then discharged through a rear wall 9 which is also provided with perforations.

Air is drawn through a front perforated outer wall 10 into the operator space and the air then moves through the operator space towards the inner wall, so that there is a constant air exchange and a continuous air movement in the space. The purpose of this is that any contaminated air is quickly replaced and sucked away from the operator.

In the fan and filter space 3 there is a set of lamps 7a with reflectors arranged and the light from these is directed towards the inner wall. The part of the light from the lamps which reaches the perforations 5 in the inner wall illuminates particles in the perforations and also illuminates particles in the operator space in the immediate vicinity of the perforations. The lamps are directed obliquely downwards, so that the particles are illuminated strongly while the operator is not hit by any major proportion of the light. This makes the particles appear with a high contrast effect. The flow of particles through the perforations is much higher than in the rest of the traction space, so lighting with light rays extending through the perforations provides a particularly visually clear illustration of the particle flow.

Fig. 2 shows part of the first embodiment in greater detail and here only a lamp 7a with a reflector is illustrated and part of the inner wall with the perforations the light from the lamp reaches. In the figure, particles in the air in the operator's space and inside the perforations have been illustrated as dots.

The concentration of particles is normally not higher in the interior of the perforations or in the light beam, but by illuminating the particles in the light beam, particles are visible that would otherwise have been invisible to the naked eye. The figure clearly illustrates how the area around the perforations is perceived to the naked eye, with a seemingly higher concentration of particles inside the perforation and along the light beam extending out of the perforation. If these, what appears from the operator's point of view, clouds of particles shaped as the beam extends through the perforation disappear, this is a clear warning that the air flow has been reduced or stopped. This may indicate that a fan has stopped or that a filter has been inserted. If the ray-shaped particle clouds instead become denser, it is an indication that particles have swirled up from some source and this may give an indication that the handling should take place more carefully.

Fig. 3 shows a second embodiment of the particle lighting, where the light sources 7b behind each perforation are lasers. The lasers are symbolically illustrated as electrical components and any necessary optics are not shown, all just to simplify understanding. The lasers are in practice components of a circuit board and the circuit board extends over the right side of the inner wall.

The circuit board has openings where the perforations are located and suitably the lasers are placed on narrow tongues which extend a bit into these openings. The light from each laser is directed obliquely downwards, in order to achieve the maximum contrast effect for the particles in the air in the same way as in the first embodiment.

Light that hits small particles is scattered and the scattering effect tends to be higher for short-wave light than for long-wave light. Blue and green light therefore gives a better contrast effect than red and orange and red light. The particle cloud therefore appears clearer with blue or green light and it is easier to achieve with lasers than with filament lamps.

Fig. 4 shows a third embodiment of the particle lighting, where the light source consists of a single laser 7b per row with perforations whose light is divided into beams with beam splitters 11. Behind each perforation a beam splitter is arranged. The laser is symbolically illustrated as an electrical component and the beam parts with symbols for optical components. In practice, the light can be conducted with light guides over a flat disk corresponding to the electrical circuit board in the second embodiment and the beam parts are designed in a much more cost-effective manner than the glass cubes as the symbols are illustrated.

Fig. 5 shows a fourth embodiment of the particle lighting, where the lighting elements in the same way as in the second embodiment consist of a set of lasers 7b. However, the lasers in the fourth embodiment are arranged on the front side of the inner wall 8, i.e. the side facing the operator space. The lasers are located just above each perforation and are directed obliquely downwards. This causes the laser beam to extend obliquely down through part of the extension of each perforation, while the interior of the perforation is unlit.

In practice, the lasers are suitably placed on a circuit board which covers the same surface as the inner wall and is provided with openings which match the perforations. The circuit board can then be cast into the inner wall so that the lasers end up in the respective perforation and the perforations themselves then function as dimmers so that no stray light from the lasers dazzles the operator without a high contrast effect.

Fig. 6 shows a fifth embodiment of the particle illumination, where the illumination element in the same way as in the third embodiment consists of a single laser 7b per row with perforations.

Alternatively, the lighting element may be a single line laser 7b. The laser is arranged on the front side of the inner wall 8 and is directed straight downwards along and immediately in front of the inner wall, so that the area in front of a whole row of perforations is illuminated. The figure illustrates how the cloud of particles extends from the laser in an elongated space parallel to the inner wall.

In the fifth embodiment, a photodetector 12 is also provided which is directed so that it primarily detects light scattered from particles in the light beam from the laser 7b. The photodetector therefore provides a measured value of the particle density in the light beam. The stream of new particles that are sucked into the perforations and then replaced by new particles on their way out gives a fluctuating signal from the photodetector which reflects the particle flow per unit time. The light from the laser can be visible to give an immediate visual indication to the operator, but with the photodetector the light can also be invisible and only detected by the photodetector. This eliminates the glare effect that the operator could otherwise be exposed to, but especially with a straight downward light beam, this effect is small. Measured values from the photodetector can then give a signal that acts as a complement to the visual effect.

The systems for lighting particles in the air are used in the described embodiments in a drawing room, but quite obviously the particle lighting can be used in many other contexts. Examples of applications are clean rooms, where the particle concentration must be kept low and it is important that an operator receives a visual indication that the particle concentration has been raised, this with an otherwise completely passive system without sensors or software for evaluating measured values from particle sensors. Still other examples of applications are smoking rooms, facilities for storage and handling of powdered foods such as flour, icing sugar and the like which can be explosive due to high particle concentrations, next to incineration plants where combustion should take place soot-free while an increased concentration of soot particles in the air indicates suboptimal combustion. .

The visual contrast effect is greater if the light beam is directed so that it does not hit the operator and if the beam extends over an area that is otherwise not illuminated or at least not heavily illuminated. The light from the particle lighting gives a greater scattering from particles with short-wave light, but if other lighting happens to be colored, it may be appropriate if the light from the particle lighting is complementary to other colored lighting, even if this means that the light from the particle lighting is long-wave. Normally it is suitable that the particle illumination extends through air portions where the particle concentration is elevated or where the particle flow is higher than in the surroundings. Typical examples are smoke extraction or openings for the transfer of coal, flour or other dusty substances.

In the described embodiments, the particle lighting with lamps and lasers is exemplified, but obviously any type of lighting element can be used, such as LEDs.

Claims (4)

A device (7a-b) for illuminating particles in the air in a drawing space (1), comprising at least one line laser (7b) arranged to emit light in a narrow light layer, where air in the drawing space is drawn out of the room through at least one perforated wall (8) and wherein the device (7a-b) for illumination is arranged to emit a light layer extending substantially parallel to and immediately adjacent the front of the perforated wall, characterized in that the light in the narrow light layer is directed straight downwards. A device (7a-b) for illuminating particles according to claim 1, characterized in that the light in the narrow light layer is shorter-wave than yellow light. A device (7a-b) for illuminating particles according to claim 2, characterized in that the light in the narrow light layer is shorter-wave than green light. A device (7a-b) for illuminating particles according to any one of claims 1-3, characterized in that the light in the narrow light layer has a color which is complementary to the color of the prevailing other lighting.