EP4249796A1

EP4249796A1 - Lighting apparatus and production method thereof

Info

Publication number: EP4249796A1
Application number: EP23163535.0A
Authority: EP
Inventors: Riccardo Gratton
Original assignee: Cortem SpA
Current assignee: Cortem SpA
Priority date: 2022-03-22
Filing date: 2023-03-22
Publication date: 2023-09-27
Also published as: IT202200005648A1

Abstract

The invention refers to a lighting apparatus (10) comprising at least one lighting body (12), provided with a housing cavity (24) configured to house inside it at least one light source (13), a covering element (17), at least one sealing element (18) and at least one encapsulation element (19). The invention also refers to a method for producing the lighting apparatus (10) according to the invention.

Description

FIELD OF THE INVENTION

The present invention concerns a lighting apparatus advantageously but not exclusively employable in areas where the formation of an explosive atmosphere, consisting of a mixture of air and flammable substances in the form of gases, vapours or fog, is likely to occur occasionally.
The lighting apparatus may be used, preferably and in a non-limiting manner, in industrial areas, construction sites, chemical industry, oil and natural gas extraction industry, petrol stations, offshore industry, marine sector, tankers, naval shipyards, power plants, public rescue services and the like.
The present invention further refers to a method for producing said lighting apparatus.

BACKGROUND OF THE INVENTION

Lighting apparatuses are known which comprise a containment body, provided with a housing in which the light source is placed, and with a compartment in which a power supply unit is placed.
This light source is suitable for generating a light beam intended, for example, to illuminate an indoor or outdoor environment, or to provide an alarm signal associated with a malfunction of a machine inside a production plant or the like. The category of such apparatuses includes, for example, headlamps, floodlights and ceiling lamps.
In particular, in lighting apparatuses the use of light sources comprising LEDs is spreading fast, since through them it is possible to obtain, compared to traditional lamps of equal power, advantages such as weight and size reduction, high efficiency with great energy savings, a long life, with consequent reduction in maintenance costs, and immediate switching on.
It is also known that, in the presence of an explosive atmosphere, the electronic components of the apparatuses can cause the triggering of an explosion of the explosive atmosphere that comes into contact with a trigger source in the apparatus. In the case of lighting apparatuses, it is possible to avoid triggering the explosion by encapsulating, i.e. segregating, the trigger source from the explosive atmosphere.
ATEX legislation requires that the lighting apparatuses that include free volumes up to 100 cm³ inside them and that must be encapsulated must pass an immersion test before encapsulation.
In particular, the current tests involve immersing the lighting apparatus, or at least the containment body, under 25 mm of water for one minute. If no bubbles escape during the immersion, the immersion tests are considered passed.
Known solutions provide for sealing the apparatus by means of a first covering element and one or more gaskets, before subjecting it to the immersion tests. Upon passing the tests, they therefore provide to encapsulate the apparatus by means of a second covering element and encapsulating silicone.
By way of example and as represented in fig. 1, the lighting body 50 of a known lighting apparatus comprises a light source 51 with LED 52, a first covering element 53 and a second covering element 54. The first covering element 53 cooperates with a sealing element 55, in particular with a gasket 55a, to ensure the airtight sealing of the lighting body 50. The second covering element 54 cooperates with an encapsulation element 56, in particular with encapsulating silicone 56a, to ensure the encapsulation of the lighting body 50. The covering elements 53, 54 are attached to the lighting body 50 by means of attachment elements 57, in particular screws 57a.
The known solutions therefore have the disadvantage of using a high amount of components, as they require both the two covering elements 53, 54 and specific attachment members for each of them. Furthermore, since it must be provided for the second covering element 54 to be arranged above the first one to completely cover it, to contain the overall sizes, there is little versatility in the production of the lighting apparatuses.
They also have the disadvantage of an increase in cost, overall size and weight of the lighting apparatus due to the greater amount of materials.
Document EP3352230A1 describes a containment structure for a lighting apparatus comprising a transparent plate and a casing, wherein between the casing and the transparent plate there is a gasket partially inserted in a recess and a sealing material which is injected into a passage formed between the plate and the casing after positioning the plate itself. This solution envisages keeping the most part of the gasket outside the casing so as to define a thickness that delimits a space between the casing and the plate, so that the two elements are never in contact with each other.
There is therefore the need to perfect a lighting apparatus, and to devise a production method that can overcome at least one of the disadvantages of the state of the art.
One purpose of the present invention is to produce a sealed and encapsulated lighting apparatus that presents reduced costs with respect to the known solutions but still meets the required sealing requirements.
One purpose is also to produce a lighting apparatus suitable for use in environments with potential risk of explosions, in which the sealing of a housing cavity configured to house a light source inside it, i.e. the potential spark ignition source, can be tested by means of the above-mentioned immersion tests.
Another purpose is to reduce the amount of materials required for sealing and encapsulation and therefore the cost and weight of the apparatus.
A further purpose of the present invention is to develop a new method for producing a lighting apparatus.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterised in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.
In accordance with the above purposes, and to resolve the technical problem disclosed above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a lighting apparatus according to the present invention comprises at least one lighting body provided with a housing cavity configured to house at least one light source inside it.
In accordance with one aspect of the present invention, said at least one lighting body comprises a single covering element of said cavity and respective at least one sealing element and at least one encapsulation element configured to cooperate with said covering element.
In other words, said cavity, and therefore the lighting body, is closed in both a sealed and encapsulated manner by means of said single covering element that cooperates both directly with said lighting body, and with said at least one sealing element and at least one encapsulation element.
In doing so, at least the advantage is obtained that the lighting apparatus, with a single covering element of the lighting body, is suitable to meet the sealing and encapsulation requirements required to allow the lighting apparatus to be used even in areas at potential risk of explosions.
According to embodiments, the covering element is placed at least partly in contact with the lighting body, in particular at an edge of said cavity, in an internal zone with respect to said sealing element.
According to one aspect of the invention, said lighting body comprises an abutment element for positioning said covering element.
According to another aspect of the invention, said abutment element comprises a step retracting in the top of side walls delimiting said cavity, which defines a positioning seat for said covering element such that said covering element is substantially flush with said lighting body. In accordance with the aforementioned purposes, a method for producing a lighting apparatus according to the invention provides to make available a lighting body provided with a housing cavity in which at least one light source is housed.
The method therefore provides to position at least one sealing element on said at least one lighting body, outside said cavity.
The method then provides to position at least one encapsulation element outside said at least one sealing element.
The method further provides to position on said at least one lighting body a single covering element configured to close said cavity and cooperate with both said at least one sealing element and at least one encapsulation element.
Advantageously, the method provides to ensure both the sealing and the encapsulation of said at least one lighting body of the lighting apparatus with a single covering element.
The method may provide, after positioning said at least one sealing element, to position said covering element on said lighting body and to attach it by means of attachment elements. It can therefore provide to carry out the immersion tests required by legislation on explosive atmosphere.
The method may then provide to remove the attachment elements and said covering element and to position said at least one encapsulation element. Finally, it can provide to position said covering element again on said lighting body.
Advantageously, the apparatus according to the invention, or at least the lighting body placed in cooperation with said sealing element and covering element, can be subjected to the immersion tests provided for by legislation on explosive atmosphere, while maintaining a reduced amount of components used, lower cost and lower weight.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

fig. 1 is a sectional view of a detail of a known lighting apparatus;
fig. 2 is a bottom view of a lighting apparatus, according to the present invention;
fig. 3 is a sectional view of a detail of the lighting apparatus of fig. 2 according to section plane III-III;
fig. 4 is a bottom view of a lighting apparatus according to a further embodiment.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.
To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

With reference to figs. 2 to 4, a lighting apparatus 10 according to the present invention comprises a containment structure 11 in which at least one lighting body 12 is positioned.
By way of example and as represented in figs. 2 and 4, the apparatus 10 comprises a lighting body 12. According to examples not represented in the figures, the apparatus 10 may comprise two, three or a series of lighting bodies 12.
The at least one lighting body 12 is provided with a housing cavity 24. The cavity 24 is configured to house at least one light source 13 inside it. The source 13 may comprise one or more lamps, halogen lamps, preferably it is an LED source 14.
For example, the source 13 may comprise one or more arrays of LEDs 14 arranged on a plurality of concentric circumferences (fig. 2), on concentric squares, arrayed on parallel rows (fig. 4), arrayed on oval or polygonal lines or the like.
The lighting body 12 may comprise a support plate 15, on which the source 13 is positioned, and one or more containment side walls 16. The support plate 15 and the one or more side walls 16 define the cavity 24.
Advantageously and as represented in fig. 3, the support plate 15 and the one or more side walls 16 are made as a single body. According to alternative embodiments not represented in the figures, the support plate 15 and the one or more side walls 16 can be made separately and joined by welding, gluing, mechanical attaching and/or the like.
The at least one lighting body 12 can be sealed and encapsulated by means of a single covering element 17. The covering element 17 can be attached to the one or more side walls 16, in particular to the top of the side walls 16.
The lighting body 12 may comprise an abutment element 25 for positioning in place the covering element 17, for example a groove, a step, positioning notches or the like.
By the term "in place" is meant that the covering element 17 is placed on the lighting body 12, so as to cover it by closing the access to the housing cavity 24.
The covering element 17 is in particular placed in contact with the lighting body 12 at least at an edge of the housing cavity 24.
In particular, the abutment element 25 is placed at the top of the one or more side walls 16.
For example and as represented in fig. 3, the abutment element 25 comprises a step 25a retracting in the top of the side walls 16.
The step 25a may define a seat in which the covering element 17 can be positioned, preferably in such a way as to be substantially flush with the lighting body 12.
The covering element 17 may be a panel or a sheet of transparent, translucent, frosted or similar glass or polymeric material, such as glass, Plexiglas or the like, whether frosted or not.
The covering element 17 may have a circular shape, with concentric ring (e.g. in fig. 2, in which the apparatus 10 has a circular shape), but also elliptical, square (e.g. in fig. 4, in which the apparatus 10 has a square shape) or other shapes.
For example and as represented in figs. 2 and 4, the apparatus 10 comprises a covering element 17 for the one lighting body 12. In forms not represented in the figures, for each lighting body 12 it might be provided a corresponding covering element 17, or a single covering element, which alone is adapted to seal and encapsulate a plurality of lighting bodies 12.
The apparatus 10 may be provided with at least one sealing element 18, such as gaskets 18a, silicone strips or the like. The at least one sealing element 18 is adapted to cooperate with the covering element 17 to seal the lighting body 12.
The apparatus 10 may further be provided with at least one encapsulation element 19, such as encapsulating silicone 19a, liquid rubber, an encapsulating paste, gasket elements or the like. The at least one encapsulation element 19 is adapted to cooperate with the covering element 17 to encapsulate the lighting body 12.
The lighting body 12 may be provided with at least a first slot 22, i.e. a special compartment, or channel, for positioning the at least one sealing element 18.
Preferably the at least one sealing element 18 is arranged for the most part inside the at least one first slot 22, wherein by "the most part" is meant that only a minimal part, less than half, preferably less than 30%, for example comprised between 0.5 and 25% of its overall height, even more preferably comprised between 0.5 and 15%, comes out.
This portion that comes out is positioned in use in contact with the covering element 17 and can be deformed by the latter.
The lighting body 12 may further be provided with at least a second slot 23, i.e. a special compartment, or channel for positioning the at least one encapsulation element 19.
For example and with reference to fig. 2, the apparatus 10 may be provided with two sealing elements 18 and two encapsulation elements 19, a sealing element 18 and an encapsulation element 19 being positioned at the inner side wall 16 of the lighting body 12, a sealing element 18 and an encapsulation element 19 being positioned at the outer side wall 16 of the lighting body 12.
With reference to fig. 4, the apparatus 10 is provided with a sealing element 18 and an encapsulation element 19.
The at least one first slot 22 for positioning the at least one sealing element 18 can be positioned towards the cavity 24 with respect to said at least one second slot 23 for positioning the at least one encapsulation element 19, in the sense that the at least one first slot 22 is closer to the cavity 24 than the at least one second slot 23.
The slots 22 and 23 may be positioned on top of the one or more side walls 16. For example, the slots 22 and 23 may be positioned at the abutment element 25.
According to embodiments, the slots 22 and 23 can be positioned at a recessed portion 26 of the abutment element 25, such that the respective edges are not in direct contact with said covering element 17.
The at least one first slot 22 may be positioned outside the cavity, in the sense that it surrounds the, or is surrounded by the, cavity 24.
For example and as represented in fig. 2, two first slots 22 can be provided, of which an outermost slot 22 surrounds the cavity 24 while the innermost slot 22 is surrounded by the cavity 24.
Likewise, the at least one slot 23 may be positioned outside the cavity 24, in the sense that it surrounds the, or is surrounded by the, cavity 24.
The at least one first slot 22 may be positioned between the cavity 24 and the at least one second slot 23 for positioning the at least one encapsulation element 19.
The slots 22 and 23 may surround or be surrounded by the cavity 24 completely. By the term "completely" is meant that the slots 22 and 23 are continuous, in the sense that they surround the, or are surrounded by the, cavity 24 without interruptions.
The at least one sealing element 18 and the at least one encapsulation element 19 may be continuous, so as to fill the aforesaid slots 22, 23 with continuity, i.e. without leaving empty spaces in the slots 22, 23.
The apparatus 10 may comprise attachment elements 20, to attach the covering element 17 to the lighting body 12. The attachment elements 20 may be screws 20a, pins, bolts, spring elements and/or the like.
The lighting body 12 may comprise sealing elements 21, for example sheets 21a with oblong slots on which attachment elements 20, for example screws 20a, may abut, sliding sheets with locking elements or the like.
The production of the lighting apparatus 10 described so far, which corresponds to the method according to the present invention, comprises making available an apparatus 10 comprising at least one lighting body 12 provided with a light source 13.
The method may provide to position, in at least one first positioning slot 22 of the lighting body 12, at least one sealing element 18. It can therefore provide to position the covering element 17 in place.
The covering element 17 can be attached by means of attachment elements 20. The positioning in place must allow the covering element to cooperate with the attachment elements 20.
The method can therefore provide to carry out the immersion tests required by legislation on explosive atmosphere.
The method may then provide to remove the covering element 17 from the seat, by acting on the attachment elements 20, for example by unscrewing screws 20a.
It is therefore provided to insert, in at least one second slot 23 for positioning the lighting body 12, at least one encapsulation element 19. For example, a suitable quantity of encapsulating silicone 19a may be provided in the at least one second slot 23.
The covering element 17 can then be repositioned in place. Advantageously, the apparatus 10 is therefore encapsulated according to legislation.
The covering element 17 can then be attached again by means of the attachment elements 20.
The suitable quantity of the at least one encapsulation element 19 may be such as to fill the at least one second slot 23 and come out to fill part of the space comprised between the covering element 17 and the side wall 16. For example, at the time of positioning the covering element 17, due to the pressure exerted by it, the quantity of the at least one encapsulation element 19 may be such that a layer S1 is formed which comes close to or preferably reaches an outer edge B1 of the abutment element 25, as represented in fig. 3.
Advantageously, on the side towards the source 13, the advance of the at least one encapsulation element 19 can be blocked by the at least one sealing element 18 in cooperation with the covering element 17. It is thus possible to obtain a good encapsulation of the apparatus 10.
For example, the suitable quantity of the at least one encapsulation element 19 may be between 5 and 20% more than the quantity necessary for only completely filling the at least one second slot 23, preferably between 10 and 15%. As a further example, in the case where the encapsulation element 19 is encapsulating silicone or rubber or the like, the suitable quantity may be that required to completely fill the at least one second slot 23 and to form a layer S1 between the covering element 17 and the abutment element 25 comprised between 0.1 and 1.5 mm, preferably between 0.2 and 1 mm, even more preferably between 0.2 and 0.5 mm.
It is clear that modifications and/or additions of parts can be made to the lighting apparatus 10 and to the method as describe heretofore, without departing from the field and scope of the present invention, as defined by the claims.
It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve other equivalent forms of lighting apparatus and method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

Lighting apparatus (10) comprising at least one lighting body (12) provided with a cavity (24) for housing at least one light source (13) inside it, characterized in that it comprises a single covering element (17) which is positioned on said lighting body (12) and cooperates both with said lighting body (12) and with at least one sealing element (18) and at least one encapsulation element (19) to close said cavity (24) in a sealed and encapsulated way.
Lighting apparatus (10) as in claim 1, characterized in that said covering element (17) is placed in contact with said lighting body (12) at least at an edge of said cavity (24).
Lighting apparatus (10) as in claim 1 or 2, characterized in that said at least one lighting body (12) is provided with at least a first slot (22) for positioning the at least one sealing element (18) and with at least a second slot (23) for positioning the at least one encapsulation element (19) and in that said at least one first slot (22) for positioning the at least one sealing element (18) is positioned outside said cavity (24) and between said cavity (24) and said at least one second slot (23) for positioning the at least one encapsulation element (19).
Lighting apparatus (10) as in claim 3, characterized in that said sealing element (18) is arranged for the most part inside said at least one first slot (22).
Lighting apparatus (10) as in any claim hereinbefore, characterized in that said lighting body (12) comprises an abutment element (25) for positioning said covering element (17).
Lighting apparatus (10) as in claim 4, characterized in that said abutment element (25) comprises a step (25a) retracting in the top of side walls (16) delimiting said cavity (24), which defines a positioning seat for said covering element (17) such that said covering element (17) is substantially flush with said lighting body (12).
Lighting apparatus (10) as in claims 3 and 5 or 3 and 6, characterized in that said slots (22, 23) are provided at a recessed portion (26) of said abutment element (25).
Lighting apparatus (10) as in any claim hereinbefore, characterized in that said at least one sealing element (18) is chosen from gaskets (18a) and silicone strips.
Lighting apparatus (10) as in any claim hereinbefore, characterized in that said at least one encapsulation element (19) is selected from encapsulating silicone (19a) and liquid rubber.
Lighting apparatus (10) as in any claim hereinbefore, characterized in that it comprises attachment elements (20), to attach said covering element (17) to said at least one lighting body (12).
Method for producing a lighting apparatus (10) as in any claim 1 to 5, characterized in that it provides to:
- make available a lighting body (12) provided with a cavity (24) for housing at least one light source (13);

- position at least one sealing element (18) on said at least one lighting body (12), outside said cavity (24);

- position at least an encapsulation element (19) outside said at least one sealing element (18);

- position on said at least one lighting body (12) a single covering element (17) which closes said cavity (24) and cooperates with both said at least one sealing element (18) and at least one encapsulation element (19).
Method as in claim 11, characterized in that it provides, after positioning said at least one sealing element (18), to position said covering element (17) on said lighting body (12) and to attach it by means of attachment elements (20); and subsequently
- to carry out immersion tests required by legislation on explosive atmosphere; and subsequently

- to remove said covering element (17) before said positioning of said at least one encapsulation element (19).
Method as in any claim 11 to 12, characterized in that it provides that said at least one sealing element (18) is positioned in at least one first positioning slot (22) comprised in the lighting body (12) and in that said at least one encapsulation element (19) is positioned in at least one second positioning slot (23) comprised in the lighting body (12).
Method as in claim 13, characterized in that it provides that the suitable quantity of the at least one encapsulation element (19) is such as to fill the at least one second slot (23) and come out in order to fill part of the space comprised between the covering element (17) and the lighting body (12) and in that the advance of the at least one encapsulation element (19) on the side towards said source (13) is blocked by said at least one sealing element (18) in cooperation with the covering element (17).
Method as in any claim 11 to 14, characterized in that it provides that the suitable quantity of said at least one encapsulation element (19) is calculated as the quantity required to completely fill said at least one second slot (23) and to form a layer (S1) between the covering element (17) and the lighting body (12) comprised between 0.1 and 1.5 mm.