A paper tube and a luminaire

Abstract

A housing for elongate luminaires is disclosed, the housing is in the form of a tube extending along a longitudinal direction, its wall thickness is greater than 2.5mm, and it is formed by winding and bonding multiple layers of paper, the multilayer paper comprises at least one inner layer, at least one middle layer and at least one outer layer, and at least one opening is further provided on a side wall of the housing as a light output window of the luminaire. A luminaire comprising said housing is also disclosed.

Description

[0001] A PAPER TUBE AND A LUMINAIRE

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates to a paper tube, and a luminaire with the paper tube as its housing, in particular to an elongate paper luminaire.

[0004] BACKGROUND OF THE INVENTION

[0005] As shown in Figure 3, a manufacturing method of kraft (paper) tube 10 is to spirally wind paper strips 12 (14, 16) on a mandrel 1 for multiple layers, wherein the layers are bonded to each other with adhesive, and after the adhesive is dried, it is taken out from the mandrel and cut to the appropriate size. In order to improve the mechanical strength, the adjacent parts of the spiral paper strips may overlap. In order to ensure a smooth appearance of the paper tube, the adjacent parts of the paper strips within each layer do not overlap, but the paper strips of the adjacent layers are interlaced with each other. The winding style shown in the diagram is carried out simultaneously with multiple layers. Of course, there are other manufacturing methods for paper tubes, such as wrapping paper layer by layer on the mandrel 1, pressing, gluing, and drying.

[0006] Because such kinds of paper tubes are degradable and inexpensive, they are used in a wide range of applications, e.g. as internal structural support for mailing packaging or furniture. For the purpose of the circular economy, it has been proposed to adopt such paper tubes as the housing of the luminaires. However, in practice, there are many technical problems to be solved, such as the fact that paper is known to be flammable. As an electrical product, fire resistance is an important consideration for whether paper tubes can be used in luminaires. The vast majority of paper tubes on the market cannot meet the requirements of fire rating for lighting equipment, and the addition of fireproof materials to paper tubes increases the complexity and cost of manufacturing.

[0007] Chinese National Standard GB7000.1-2015 and the International Electrotechnical Commission Standard IEC 60598-1 : 2014 specify the requirements for the fire-proof rating of lighting equipment. SUMMARY OF THE INVENTION

[0008] The invention is defined by the claims.

[0009] After a large number of experiments, the inventors of the present disclosure found specific paper materials. Paper tubes made of such materials as housing of luminaires can meet the fire-proof requirement of lighting equipment without the need to add additional materials such as fire extinguishant and flame retardants.

[0010] According to examples in accordance with an aspect of the invention, there is provided a housing for an elongate luminaire, wherein the housing is in a tubular shape extending along a longitudinal direction, a wall thickness of the housing is greater than 2.5mm, and the housing is formed by winding and bonding multiple layers of paper, and the multiple layers of paper comprises at least one inner layer, at least one middle layer and at least one outer layer, and at least one opening is further provided on a side wall of the housing as a light output window of the luminaire.

[0011] Taking an elongate luminaire with a length of about one meter as an example, the housing may be generally chosen as a round tube with a diameter of about 40-80mm, or a rectangular tube with edge lengths of 40-80mm in cross-section. In such cases, the wall thickness may be 3 mm. When a rectangular tube is used as a housing, a light output window is opened on one of its sides. The area of this output window can occupy at least 90% of the area of this side.

[0012] The inner, middle and outer layers may be a layer of paper or multiple layers of paper. For example, the outer layer may be made of two layers of paper that staggered overlap each other to ensure a smooth and flat appearance. The middle layer may be made of three or more layers of paper to provide sufficient strength. Similarly, the inner layer may also be made of two staggered overlapping layers of paper because it requires a high surface requirement for the installation of light sources, optics and even driver components.

[0013] In a preferred example, the outer layer comprises kraft paper or ivory board; the middle layer comprises bobbin paper; and the inner layer comprises kraft paper or ivory board.

[0014] In another preferred example, the outer layer comprises kraft paper or ivory board; the middle layer and the inner layer both comprise bobbin paper.

[0015] In yet another preferred example, the outer layer comprises kraft paper or ivory board; the middle layer and the inner layer both comprise kraft paper or ivory board. In some examples, the paper tube that forms the housing comprises 6 layers of bobbin paper and 1 layer of kraft paper or ivory board on the outside, and the total wall thickness is about 3 mm.

[0016] In some other examples, the paper tube that forms the housing comprises 7 layers of kraft paper or ivory board, and the total wall thickness is about 2.6 mm.

[0017] Kraft paper, see GBT22865-2008; (white) ivory board, see GB / T22806-2008; such kinds of paper have a smooth surface and a relatively dense structure. Bobbin paper, see QBT1457-1992, is tough and wear-resistant, has good water resistance, and may resist edge indentation and lathe processing when used. In the examples of the present disclosure, when kraft paper or ivory board is adopted as a layer of the multilayer paper, the specification of the kraft paper or ivory board includes compressive strength at ring crush index of > 8.5 N m / g and grammage range of 150 - 280g / m2; when bobbin paper is adopted as a layer of the multilayer paper, the specification of the bobbin paper includes compressive strength at ring crush index of > 14 N m / g and grammage > 360 g / m2. The test methods of the above specifications may be found in Chinese national standards such as GB / T 451.2-2002 and GB / T 2679.8-2016 or international organization standards such as ISO 15754-2009.

[0018] In some examples, at least one inner layer and / or at least one outer layer further comprises a metal foil layer, such as aluminum foil.

[0019] It’s beneficial to have aluminum foil on the inner layer for the opening of a light window on the side wall of the housing. Pure paper tube is formed from cellulose fiber material. When cutting, especially when cutting from the outside to the inside, the blade will inevitably pull out the fibers on the inner edge of the paper tube wall, resulting in a brushed burr on the edge of the cutting surface. Aluminum foil does not contain fibers, and when cutting this opening to create a light output window, the blade may leave a neat cutting edge at the foil layer, resulting in a smooth edge of the opening.

[0020] It’s beneficial to have aluminum foil on the outer layer for fireproofing and waterproofing. Metals conduct heat quickly and are not prone to fire. It is also difficult for moisture to penetrate through the metal foil into the inside of the housing.

[0021] In an exemplary manufacturing process, the aluminum foil layer may be attached to the surface of the corresponding paper layer. Once the paper tube is wound and formed, this foil layer may be located on the outermost or innermost surface, or it may be located on a second layer from the outer (or inner) layer. When the foil layer is on the outermost, the paper tube has a metallic appearance, and when it is placed on the second layer from the outside, the paper tube still has the natural color of the paper. In other manufacturing processes, a segment of aluminum foil may be connected to the end of a paper strip before winding, and then the paper strip with aluminum foil is wound according to the ordinary process, so that the innermost or outermost layer of the paper roll is the aluminum foil.

[0022] According to examples in accordance with another aspect, the present disclosure seeks to provide a luminaire comprising the aforementioned housing; a light source part and an optical component are provided within the housing.

[0023] Preferably, the light source part component comprises a plurality of LED chips arranged on a strip-shaped substrate; the optical component comprises a reflector and a diffuser; wherein the reflector is arranged around a bottom side and two sides of the light source part to form an optical chamber; the diffuser is arranged over the light source part and covers the opening on the side wall of the housing.

[0024] The paper tubes disclosed in this disclosure are made of paper of specific specifications, and the housing of the luminaires made from such paper tubes does not require additional flame retardants. The luminaires made with such housing meet the fire rating specifications of lighting equipment.

[0025] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0028] Fig. 1 illustrates the appearance of a housing of present disclosure;

[0029] Fig. 2 illustrates the (partial) appearance of a luminaire of present disclosure; and

[0030] Fig. 3 illustrates the paper tube fabrication method of prior art.

[0031] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The invention will be described with reference to the Figures.

[0033] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0034] Fig. 1 shows a luminaire housing 10 made with a paper tube according to the present disclosure. It extends in the direction along the longitudinal axis X, and its side wall is provided with an opening 11.

[0035] With reference to Fig. 2, a light source part 21 is installed in the housing 10, and a reflector 26 folded from reflective paper may be arranged around the light source part. The light source part 21 comprises a strip-shaped substrate 22 and a plurality of LED chips 24 mounted on the substrate. The opening 11 on the side wall of the housing 10 is the light output window of the luminaire. A diffuser (not shown) may also be set at the light output window to improve the uniformity of the light output of the luminaire. End caps (not shown) may also be arranged at both ends of the housing 10, and the ends of this paper tube are thus closed.

[0036] The multilayer paper constituting the paper tube may be divided into inner layer 12, middle layer 14 and outer layer 16 (see reference signs in Fig. 3). Each of these layers may include one or several layers of paper. The paper used for each layer may include kraft paper, ivory board or bobbin paper. Among them, kraft paper and ivory board have smooth surfaces and are suitable for use on the inner and outer surfaces of paper tubes; the bobbin paper has a strong structure, and because it is made of recycled pulp, it is inexpensive and suitable for use in the inner tube of the paper tube. However, such a configuration is not absolute, it may also be that all layers of the entire paper tube are made of kraft paper or ivory board, or all layers are made of bobbin paper; and it is also possible to use only kraft paper or ivory board for the outer layer, and bobbin paper for other layers.

[0037] It should be noted that the paper specification that may make the paper tube meet the fire-proofing requirements of lighting products are: the compressive strength at ring crush index of kraft paper or ivory board > 8.5 N m / g and grammage range of 150 - 280g / m2; the compressive strength at ring crush index of bobbin paper > 14 N m / g and grammage > 360 g / m2. Tables 1 and 2 below illustrate the composition of kraft paper or ivory board (collectively referred to as kraft / ivory board) and bobbin paper. The layers of paper that make up the paper tube are coated with glue and dried. An example of the composition of glue is shown in Table 3. The specifications of some bobbin paper and kraft / ivory board are shown in Table 4 and Table 5, and according to the above requirements, the paper tube with sufficient fire resistance involved in the production of suitable paper products may be selected as the housing of the luminaire. Table 1 : Kraft / ivory board composition

[0038] Table 2: Composition of bobbin paper

[0039] Table 3: Glue composition Table 4: Specifications of bobbin paper above grade B

[0040] Table 5: Kraft / ivory board specifications

[0041] In a specific embodiment, the length of the elongate luminaire is about one meter, and its housing is selected from a round paper tube with a diameter of about 60mm. In an alternative embodiment, the housing is a rectangular paper tube with a cross-sectional side length of about 60 mm. The corresponding paper tube is made of 6 layers of bobbin paper and 1 layer of kraft / ivory board on the outside, with a total wall thickness of about 3 mm. In an alternative embodiment, the paper tube is wound with 7 layers of kraft / ivory board, and the total wall thickness is about 2.6 mm.

[0042] Kraft / ivory board uses kraft pulp (sulfate pulp), which is treated with sodium sulfide in the production process, so the sulfur content is high. Bobbin paper is manufactured from recycled paper, let alone that it is also high in sulfur. In the luminaires made of these materials, when the temperature rises after it’s lit up, microscale amount of sulfide will vaporize, and react with the silver electrodes or reflective layer of the LED in the light source, making them blackened, resulting in the loss of LED light efficiency and even shortening the service life of the luminaire. For this reason, a certain baking process may be used to make the sulfide be volatilized somehow first. Then, in the normal use of the luminaire, the amount of sulfide volatilized will be significantly reduced, so as to achieve the purpose of prolonging the life of the product. Particularly, the paper tube may be cut to the required length after it has been formed, and then placed in baking equipment such as an oven. After being baked at a temperature of about 80 °C for 2-4 hours, the paper tube is then opened a light output window and finally proceeded with trimming, drilling and installing other components.

[0043] Metal foil may also be added to the paper tube to further improve its mechanical properties and fire / water resistance. Aluminum foil, for example, may be covered on the inner and outer surfaces of the paper tube, or embedded in the multiple layers of paper underneath the surface. In particular production, aluminum foil may be attached to the surface of the paper, or attached to the end of the paper, and then it may be pressed, glued, and dried on a mandrel in the way of normal paper winding or wrapping.

[0044] When the metal foil is placed on the outer surface of the paper tube, it may give the luminaire a metallic appearance.

[0045] When the metal foil is located on the inner surface of the paper tube, it is helpful for opening a neat light output window with smooth edge(s).

[0046] When the metal foil is embedded in the paper tube interlayer, it not only maintains the natural color of the paper tube, but also increases the performance of preventing water or water vapor penetration, and its extremely high thermal conductivity is beneficial for improving the fireproof rating of the paper tube.

[0047] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0048] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0049] If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to". If the term "arrangement" is used in the claims or description, it is noted the term "arrangement" is intended to be equivalent to the term "system", and vice versa. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A housing (10) for an elongate luminaire, wherein the housing is in a tubular shape extending along a longitudinal direction (X), a wall thickness of the housing is greater than 2.5mm, and the housing is formed by winding and bonding multiple layers of paper, and the multiple layers of paper comprises at least one inner layer (12), at least one middle layer (14) and at least one outer layer (16), and at least one opening is further provided on a side wall of the housing as a light output window of the luminaire.

2. The housing (10) of claim 1, wherein the outer layer (16) comprises kraft paper or ivory board.

3. The housing (10) of claim 2, wherein the middle layer (14) comprises bobbin paper.

4. The housing (10) of claim 3, wherein the inner layer (12) comprises kraft paper or ivory board.

5. The housing (10) of claim 2, wherein both the middle layer (14) and the inner layer (12) both comprise bobbin paper.

6. The housing (10) of claim 2, wherein both the middle layer (14) and the inner layer (12) both comprise kraft paper or ivory board.

7. The housing (10) of any one of claims 2 to 6, wherein when adopting kraft paper or ivory board as a layer of the multiple layers of paper, the specification of this kraft paper or ivory board includes compressive strength at ring crush index of > 8.5 N m / g and grammage range from 150 to 280g / m2; when bobbin paper is adopted as a layer of the multiple layers of paper, the specification of the bobbin paper includes compressive strength at ring crush index of > 14 N m / g and grammage > 360 g / m2.

8. The housing (10) of claim 1, wherein at least one inner layer (12) and / or at least one outer layer (16) further comprises a metal foil layer.

9. A luminaire, comprising the housing (10) as claimed in any one of claims 1 to 8; a light source part (21) and an optical component are provided within the housing.

10. The luminaire of claim 9, wherein the light source part (21) comprises a plurality of LED chips (24) mounted on a strip-shaped substrate (22); the optical component comprises a reflector (26) and a diffuser; wherein, the reflector (26) is arranged around a bottom side and two sides of the light source part (21) to form an optical chamber; the diffuser is arranged over the light source part (21) and covers the opening on the side wall of the housing.

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