EP1684006A2 - Lighting device, in particular for tunnel lighting - Google Patents

Abstract

The fixture has a lamp (4) and a ballast (10) for operating the lamp. A latent heat storage unit (7) containing a phase changing material is integrated in the fixture for protecting the ballast from heat. The storage unit partly and outwardly shields the ballast. The phase changing material is water, paraffin or salt hydrate. The ballast is thermally isolated from the housing of the fixture and is thermally connected with the unit (7).

Description

Technical area

The present invention relates to a luminaire and to its use for lighting tunnels.

State of the art

The term light designates a lighting device with a lamp (light source) and other technical parts, such as a housing, electrical connections for the lamp and other. In the present case, lights are considered, which also include a ballast for the operation of the lamp, so an electrical circuit that is necessary for the operation of the lamp to a power source.

Luminaires are known in various forms, for example for general lighting, lighting of industrial plants or traffic areas. In particular, lights are also used under circumstances that require a lingering for a certain time lighting in the event of a fire. This is especially true for tunnels.

Presentation of the invention

The invention is based on the technical problem of specifying a lamp which is advantageously suitable for use under conditions under which the luminaire must continue to operate in the event of a fire for a certain period of time.

The invention is directed to a luminaire with a lamp and with a ballast for operating the lamp, characterized by a built-in the lamp, a phase change material containing latent heat storage to protect the ballast from heat, which at least partially shields the ballast to the outside,
and their use for lighting a tunnel.

Preferred embodiments are specified in the dependent claims. The individual features embodied in this and in the following description relate both to the luminaire as a device and to its use, without being distinguished in detail here.

The basic idea of the invention is to provide a latent heat accumulator in a luminaire. The latent heat storage device is characterized in that it contains a phase change material (short phase change material, PCM for short) provided for this purpose, that performs a phase transition, for example melts or vaporizes, in a relevant temperature range. In this phase transition, a so-called. Latent energy for the phase transition is required, which does not make itself noticeable as such in a temperature increase. Depending on whether it is a pure material having a phase transition at a fixed phase transition temperature or else a mixture with a phase transition which distributes over a certain temperature range, the phase transition can take place without a temperature change or with a temperature change. In any case, the phase transition "absorbs" the latent energy without it expressing itself in a heat capacity corresponding increase in temperature.

Such latent heat storage, for example, in the form of so-called. Cold cuffs for cooling drinks or heat pad for Warming hands in coat pockets known. In the latter case, however, the latent heat output and non-absorption is used.

In the case of tunnel luminaires and other luminaires intended to function in the event of a fire for a period of time, the energy absorbed by the heat conduction of the enclosure and otherwise supplied from outside must be absorbed to prevent excessive heating, in particular of the ballast. In general, the ballast is the most temperature-sensitive part of a lamp and in case of fire particularly cool. For example, in the event of a fire, a tunnel luminaire should be able to operate for at least one hour at an ambient temperature of 250 ° C. A longer operability at this temperature or a resistance to even higher temperatures is of course only an advantage. Also, lower requirements may exist in other applications. With the latent heat storage, so a specially provided for the purpose of energy absorption by a phase transition material, the ballast in the lamp and, if necessary, the lamp and other lighting parts for a prolonged period of time remain at an operable temperature and continue to work. The energies to be absorbed by phase transition are much larger than the usual heat capacity multiplied by a tolerable temperature rise relative to the required mass of the phase change material. Thus, the invention provides a favorable combination of relatively effective heat protection on the one hand and not oversized size or not oversized weight of the lamp.

Of course, a plurality of ballasts and / or lamps may be provided in the luminaire.

Preferred phase transition materials include water, paraffins, salt hydrates and their eutectic mixtures. Such or other phase change materials should preferably be in thermal, in particular large, connection to the ballast. On the other hand, the ballast should thermally isolated as possible with respect to the housing be so with smallest possible contacts and otherwise an air insulation layer or be mounted on intermediate insulating materials.

Furthermore, the latent heat storage should surround the ballast as possible, d. H. preferably at least 80% of the outer surface of the ballast. This area is meant in the sense of an envelope around the ballast, which can show in a particular case so relatively complicated forms. Preferably, the ballast is completely surrounded by the latent heat storage of mounting connections and lines apart. However, embodiments are also conceivable in which a relatively large latent heat storage is only in partial thermal contact with the ballast, but cools the interior of the lamp as a whole. Such constructions may be simpler and would protect, in addition to the ballast, the lamp and other lighting components to some extent.

The latent heat storage generally requires a container for receiving the phase change material. This container is preferably elastic when, during the phase transition, a volume change occurs to some extent. It may additionally or alternatively also have a compensation volume into which the phase transition material can expand. Especially in the case of phase transitions into the gaseous state of aggregation, however, it is also possible for a purging line, preferably with a pressure relief valve, to be present in order to be able to discharge the gas volumes, which are then generally very large, to the outside. This measure may be combined with the aforesaid, but in general elastic containers and compensating volumes for phase transitions into the liquid state and the discharge lines for phase transitions into the gaseous state will be considered. The pressure relief valve prevents unwanted evaporation in continuous operation of the device without a fire and releases the gas only from a certain pressure, which is to be assumed only in case of fire.

Typical and preferred magnitudes for the suitable phase transition energy in a luminaire according to the invention are in the order of 0.1-5 kWh, more preferably above 0.2 or 0.3 kWh and / or below 3 kWh or 2 kWh or 1 kWh ,

Typical and preferred temperature ranges for the phase transition are between 50 ° C and 120 ° C.

The invention is particularly advantageous in the case of an electronic ballast, in short ECG. ECGs are typically much more sensitive to heat than conventional ballasts with chokes or other non-electronic components. In particular, as a lamp, a fluorescent lamp into consideration, which should be operated for reasons of economy with a ballast, but may also be a high-pressure mercury vapor lamp, high-pressure sodium vapor lamp or low-pressure sodium vapor lamp.

In this case, the luminaire according to the invention can have an electronic ballast mounted essentially within the latent heat accumulator, which is mounted in this form with the latent heat accumulator above the lamp and, if appropriate, a reflector of the lamp, an insulation distance in particular being maintained between the luminaire housing and the latent heat accumulator. In this case, the latent heat storage can have a good thermal contact with a lamp reflector and thus cool the lamp via the reflector (via radiation exchange). Reference is made to the exemplary embodiment for illustration.

Brief description of the drawings

in Figur 1

in einer schematischen Seitenansicht im Ausschnitt und

in Figur 2

schematisch im Querschnitt dargestellt.

This embodiment described below is

in FIG. 1

in a schematic side view in the neck and

in FIG. 2

shown schematically in cross section.

The individual features can also be essential to the invention in other combinations.

Preferred embodiment of the invention

FIG. 1 shows a luminaire 1 according to the invention with a luminaire housing 2. FIG. 1 shows only a section of the ceiling area of the luminaire housing 2, whereas FIG. 2 also shows side walls connecting thereto in cross section. The luminaire housing is closed at the bottom by a disc 3 for light emission.

In the housing 2 and above the disc 3, a fluorescent tube is arranged as a lamp 4, which extends below the vertical center of the lamp housing, in the width direction centric and parallel to the longitudinal direction of the lamp housing 2 elongated. Above the lamp 4 is the vertex of a parabola 5 extending therefrom obliquely downwards from two sides. The parabolic reflector 5 runs up to the transitions between the pane 3 and the side walls of the housing 2. The described parabolic shape lies in the sectional plane of the cross section 2, whereas the reflector 5 otherwise extends in an elongated manner parallel to the longitudinal direction of the housing 2 and to the lamp 4.

At the apex line of the parabolic reflector, a latent heat accumulator 7 is mounted above the spacer pin 6, so that the parabolic reflector can be cooled by the spacer bolts 6 through the latent heat accumulator 7. It is an alternative to the salt hydrate barium hydroxide octahydrate (Ba (OH) ₂ • 8H ₂ O) or the eutectic mixture magnesium nitrate hexahydrate / lithium nitrate (Mg (NO ₃ ) ₂ • 6H ₂ O / Li (NO ₃ ) ) or heat-wax filled vessel, in which an elastic container (not shown separately) is provided. Alternatively, the vessel of the latent heat accumulator may also contain, for example, simple water, with a purge line 8 shown in the figures being added to the overpressure valves 9. The pressure relief valve is usefully at the highest point of the container arranged. This one is also elastically constructed to be frost-proof. Furthermore, compensation volumes of, for example, about 20-30% of the container volume can be provided.

The latent heat accumulator 7 is preferably in one piece and contains in itself a cavity with an electronic ballast 10 of the operation of the lamp 4 via not shown in detail lines. It may be, for example, a square tube with inserted ballast or an elastic sheath around the ballast, the lines are guided through the frontal openings.

The invention has the function in the form of this embodiment, a heating of the lamp 1 in the event of a fire in a tunnel by a phase transition in the latent heat storage 7 for a period of at least 1 h of the electronic ballast 10 and thus prevent its functioning over the said hour sure. The lamp 4 and the reflector 5 are significantly less sensitive to heat and must not be included in this protection. Thus, in an emergency for a certain time a lighting of the tunnel can be ensured, which is especially after the recent experience with severe tunnel gaps in tunnels of great importance.

The function of the invention will be illustrated by a few numerical examples. The surface of the luminaire 1 can typically be 2 m ² . Assuming an internal air insulation distance of 30 mm and a temperature difference of 200 ° C, the result is a heat input of 490 watts. If, with soot-blackened pane 3, a small light emission and thus an almost complete coupling in of the internal thermal power of the lamp 4 and of the ballast 10 are assumed, then about 60 watts (assuming a 54-watt lamp) are added. So 0.55 kWh have to be buffered.

If you allow a temperature increase, for example, from 50 ° C normal operating temperature to 120 ° C maximum operating temperature, so you would need the heat capacity of, for example, about 75 kg of copper or 61 kg of iron. However, because of the phase transition at 100 ° C, only about 730 g of water would be needed, thereby ensuring a temperature limit of 100 ° C. Here, the latent heat accumulator 7, as shown in the figures, be equipped with a blow-out and to prevent inadvertent evaporation in normal operation a pressure relief valve 9. The large volumes of water vapor produced do not make sense with compensating volumes.

Heat paraffin has a usable phase transition from the solid to the liquid state and is thereby frost-proof and maintenance-free, since it does not evaporate. A pressure relief valve and a blow-off line are therefore not necessary. It is also non-toxic, chemically inert, non-hazardous to water and has a flash point of about 300 ° C. It would require about 6.5 kg of heat with a melting point of 90 ° C or 7.3 kg with a melting temperature of 100 ° C, so compared to water significantly larger masses.

Also the mentioned salt hydrates barium hydroxide octahydrate and the eutectic mixture magnesium nitrate hexanitrate / lithium hydrate are considered. In this case, about 5.8 or about 7.9 kg are required. However, these materials are corrosive and should therefore not escape, but remain held in equalization volumes or elastic containers.

Claims (15)

Light (1)
with a lamp (4)
and with a ballast (10) for operating the lamp (4),
characterized by a in the lamp (1), a phase change material containing latent heat storage (7) for protecting the ballast (10) from heat, which at least partially shields the ballast (10) to the outside. Luminaire (1) according to claim 1, wherein the phase change material is water, a paraffin, a salt hydrate or a eutectic salt hydrate mixture. Luminaire (1) according to claim 1 or 2, wherein the ballast (10) relative to a housing (2) of the lamp (1) is thermally insulated. Luminaire (1) according to one of the preceding claims with a thermal connection between the ballast (10) and the latent heat storage (7). Luminaire (1) according to one of the preceding claims, in which the latent heat accumulator (7) at least encloses the ballast (10) in a proportion of 80% of the outer surface of the ballast. Luminaire (1) according to one of the preceding claims, in which the latent heat store (7) contains the phase change material in an elastic container. Luminaire (1) according to one of the preceding claims, wherein the latent heat accumulator (7) has a compensation volume in a container for the Phase change material for compensating for volume changes in the phase transition. Luminaire (1) according to one of the preceding claims, in which the latent heat accumulator (7) has a blow-off line (8) for blowing out vapor arising during the phase transition, preferably with a pressure relief valve (9). Luminaire (1) according to one of the preceding claims, in which the total phase transition energy of the phase change material is between 0.1 kWh and 5 kWh. Luminaire (1) according to one of the preceding claims, in which the phase transition takes place in a temperature range between 50 ° C and 120 ° C. Luminaire (1) according to one of the preceding claims, in which the ballast is an electronic ballast (10). Luminaire (1) according to one of the preceding claims, in which the ballast (10) is mounted in the latent heat accumulator (7) above the lamp (4) and, if present, a reflector (5) of the lamp (4), between the Lamp (4) and optionally the reflector (5) and the latent heat storage (7) an isolation distance is maintained. Luminaire (1) according to one of the preceding claims, in which the lamp is a fluorescent lamp (4). Luminaire (1) according to one of the preceding claims, wherein the latent heat accumulator (7) has a good thermal contact with a reflector of the lamp (4) and thus can cool the lamp. Use of a luminaire (1) according to one of the preceding claims for illuminating a tunnel.

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