WO2009121753A1

WO2009121753A1 - Spotlight with a louver flange

Info

Publication number: WO2009121753A1
Application number: PCT/EP2009/053435
Authority: WO
Inventors: Flavio Mauro Sangiorgio
Original assignee: FAEL SpA
Current assignee: FAEL SpA
Priority date: 2008-04-03
Filing date: 2009-03-24
Publication date: 2009-10-08
Anticipated expiration: 2010-10-03
Also published as: ITMI20080576A1

Abstract

There is described a spotlight (1) with a louver flange (5) comprising a hollow body (50) with an inner edge (9) which may be sealably coupled with the spotlight (1) free of lens (6), and an outer edge (10) sealably supporting the lens (6). Said spotlight may further includes a spacer (7) with an outer coloured filter (8) which may be fitted on outer edge (10) of the hollow body (50) with lens (6), i.e. downstream of lens (6).

Description

"Spotlight with a louver flange" * * *

DESCRIPTION

The present invention relates to a spotlight with a louver flange. Louver flanges (or simply louvers) for outdoor spotlights are known to be used in order to control the luminous flux and direct it towards the zone to be illuminated, thus limiting the output angles of the light rays that would generate dazzling thus reducing the scattered light as well as the maximum intensity and efficiency. The louver (typically made of welded steel) is usually fitted downstream of the spotlight lens (or glass). If the spotlight is facing upwards, e.g. for illuminating the facades of buildings or monuments, a considerable increase in the lens temperature occurs. The maximum temperatures allowed on the lens are about 260 ⁰C, beyond which breaks occur (especially in case of rainy weather).

Considering the geometrical measures of the spotlight, for over 1,000 watts lamps, fitting traditional louvers generates a thermal state such that temperatures reach unacceptable levels. Considering that the illumination (in particular the one for upward projection) required considerable powers, the 260 ⁰C thermal limitation is rapidly exceeded.

Ceramic glasses are currently used in order to solve the problem, which are however very expensive and fragile.

The situation worsens in the case of applying coloured filters, e.g. made of paste, which become increasingly heated (beyond 300 ⁰C with 1,000 watts lamps) than a transparent lens because of the absorbed light radiation, even if the spotlight is facing downward.

It is therefore the object of the present invention to implement a spotlight with a louver flange which reduces light-scattering and limits the lens heating up, while preserving acceptable performances in terms of optical efficiency (η) and maximum intensity (Imax) of the light source. In accordance with the invention, such an object is achieved by means of a spotlight with a louver flange, characterized in that said flange comprises a hollow body with an inner edge which may be water-tightly coupled with the lens-free spotlight, and an outer edge supporting the watertight lens.

These and other features of the present invention will be made more apparent by the following detailed description of an embodiment thereof, illustrated by way of non- limitative example in the accompanying drawings, in which: figure 1 shows a front view of a spotlight with a louver flange according to the invention; figure 2 shows a section view according to line H-II in figure 1 ; figure 3 shows a section view similar to that in figure 2 with a spacer included. With reference to figures 1 and 2, there is shown a spotlight 1 equipped with a mount 2, a reflecting parabola 3, a light source 4 and a louver flange 5 made of pressed aluminium.

Louver flange 5 consists of a thin hollow body 50 having an inner edge 9 and an outer edge 10. The inner edge 10 of louver 5 has simply been sealably fitted on the outer edge 20 of spotlight 1 from which lens 6 has been removed, which lens has instead been sealably fitted on the outer edge

10 of louver 5.

The watertight volume now also includes the space contained in flange 5. Therefore, the heat produced by lamp 4 dissipates more and lens 6 heats up much less, particularly if the spotlight is directed upward.

The traditional louvers are simply fitted on the outer edge 20 of spotlight 1 including a lens 6, simply aiming at limiting the light-scattering against the above-mentioned disadvantages.

The experimental results (efficiency means the percentage ratio of the flux of spotlight 1 to the flux of lamp 4) obtained by means of a commercially available automatic photogoniometer (LMT model GO- V 1900) are quoted below and are intended to appreciate the differences between the same spotlight 1 (a 1,000 watts LM ONE produced by the present Applicant) equipped with a traditional louver and with a louver flange 5 according to the invention.

Table: efficiency and maximum intensity, the reduction in light-scattering being equal.

Table: temperatures for an upward facing spotlight, i.e. under extreme heat conditions of usage.

In the first Table, we may appreciate an increase in efficiency and, especially, in the maximum intensity which substantially remains equal to the case of louver lack, i.e. the maximum intensity remains constant though decreasing the scattered light.

By analysing the second Table, a considerable temperature drop may be noted, which allows even 2,000 watts spotlights to be used in complete safety.

With a blue-coloured lens (the blue filter creates the worst thermal situation), again with the spotlight facing upward, a temperature of 190 ⁰C is reached with a 1,000 watts spotlight, otherwise exceeding 300 ⁰C. On the other hand, by using 2,000 watts spotlights, we are well beyond 300 ⁰C even with the flange 5 according to the invention.

In figure 3, a spotlight 1 is shown according to the configuration in figure 2, to which a spacer 7 has been added which pulls a coloured filter 8 fitted thereon away from the light source 4, thus reducing the thermal exposure thereof. The space between the lens 6 fitted on louver 5 and the coloured filter 8 is non-sealably ventilated in order to scatter the produced heat. In this embodiment, acceptable temperature values are achieved even by means of 2,000 watts lamps.

Claims

1. A spotlight with a louver flange (5), characterized in that said flange (5) comprises a hollow body (50) with an inner edge (9) which may be water-tightly coupled with the spotlight (1) free of lens (6), and an outer edge (10) supporting the watertight lens (6).

2. A spotlight with a louver flange (5) according to claim 1, characterized in that it includes a spacer (7) with an outer coloured filter (8) which may be fitted on the outer edge (10) of the hollow body (50) with lens (6), i.e. downstream of lens (6).

3. A spotlight with a louver flange (5) according to claim 1 or 2, characterized in that said flange (5) is made of pressed aluminium.