Apparatus for stimulating flames

Abstract

 The invention relates to an apparatus for simulating a fire, in particular for use in a fireplace and the like, comprising a number of light-emitting diodes (LED's) (2), which can be controlled and varied as regards intensity according to a predetermined programme, in which the emitted light beams can be projected onto a projecting surface (6) via a diffuser, wherein at least one transparent plate (4) is disposed between the LED's and the projecting surface, which plate is provided with a pattern of protrusions (5) on the light exit side thereof, which plate or plates (4) and which LED's (2) are movable with respect to each other during operation.

Description

[0001] The invention relates to an apparatus for simulating a fire, in particular for use in a fireplace and the like, comprising a number of light-emitting diodes (LED's), which can be controlled and varied as regards intensity according to a predetermined programme, in which the emitted light beams can be projected onto a projecting surface via a diffuser.

[0002] An apparatus as described above for simulating candlelight is disclosed in US patent no. 5,924,784. In this known apparatus, a number of LED's are controlled by means of a microprocessor according to a predetermined programme, in such a manner that a fairly random switching sequence of the LED's as well as a variation of the intensity is obtained, so that a fairly natural simulation of candlelight is achieved. According to the aforesaid US patent specification, such an apparatus is also used in fireplaces for simulating the pattern of fire and flames of a natural open fire.

[0003] One drawback of this known apparatus is the fact that the shape, the colour and the height of the flame and the manner of control via a recurring pattern results in a rather unnatural image of flames, in which the recurrence in the pattern is clearly recognizable.

[0004] The object of the invention is to overcome this drawback and to provide an apparatus which produces a very natural simulation of a normally burning wood fire.

[0005] In order to accomplish that objective, the apparatus according to the invention is characterized in that at least one transparent plate is disposed between the LED's and the projection surface, which plate is provided with a pattern of protrusions on the light exit side thereof, which plate or plates and which LED's are movable with respect to each other during operation.

[0006] With the apparatus according to the invention, the LED's are controlled to go on and off according to a predetermined programme, and also their intensity is varied according to this programme. In itself, this already leads to a very variable image of flames, which still looks slightly unnatural, however.

[0007] An improvement can be obtained by projecting the light emitted by the LED's via the transparant plate with protrusions on its light exit side on a projection surface, which can be the rear wall of an open fire-place.

[0008] As a result, the image of flames that is projected onto the projection wall is enlivened to a considerable degree, which effect is further enhanced by moving the transparent plate(s) forward and backward with respect to the LED's. This results in a image of flames which bears great resemblance to the image of flames of a natural wood fire.

[0009] In an advantageous embodiment of the apparatus according to the invention, the transparent plate is a rotatable cylinder, which surrounds the LED's.

[0010] The protrusions that are present on the light exit side of the transparent plate may exhibit various shapes. Thus, they may in the form of round protrusions or protrusions provided with facets, but in practice it has become apparent that especially protrusions having a prismatic shape are quite satisfactory as regards the provision of a lively image of flames.

[0011] One remarkable aspect of the apparatus according to the invention is the fact that in order to obtain an optimally true-to-nature simulation of an open fire, the electronic control of the light sources according to a predetermined programme is combined with the mechanical movement of the plate by means of which the light from the light sources is projected onto the projection surface.

[0012] In another embodiment of the apparatus according to the invention, in order to effect an even further improvement in this regard, a number of reflecting surfaces are arranged on the light exit side of the transparent plate, which surfaces include mutually different angles with each other and which project the exiting light onto the projection surface.

[0013] Preferably, the reflecting surfaces of said embodiment are movably disposed with respect to the LED's and the transparent plate.

[0014] The reflecting surfaces may be formed of a number of strips of a reflecting material, which are arranged on a rotatable shaft.

[0015] According to another advantageous embodiment, the LED's, which have different colours, are arranged in a number of groups. Also the reflecting surfaces may exhibit different colours.

[0016] In this way, an apparatus is obtained by means of which a burning fire can be simulated in a very true-to-nature manner.

[0017] The invention furthermore relates to a fireplace comprising an apparatus for simulating a fire as described above, wherein the LED's are arranged on one or more printed circuit boards extending in the transverse direction of the fireplace, and wherein the transparent plate and the reflecting surfaces are so arranged that the light can be projected onto the rear wall of the fireplace.

[0018] All this leads to a fireplace having a very small overall depth whilst retaining a high-quality fire simulation of fire and flames.

[0019] Another embodiment of the open fire according to the invention is characterized in that a cover plate is disposed above the cylinder-shaped transparent plate, which cover plate limits the height of the flame and which is provided with a template of flame forms on the side that faces towards the rear wall. Such a template enables an even better simulation of the natural form of the flame.

[0020] Another embodiment of the fireplace according to the invention includes programmable means for producing a sound simulating a burning wood fire, with means being present for synchronising the control programme of the LED's and the means for producing the sound.

[0021] The invention will now be explained in more detail with reference to the drawing, which shows two exemplary embodiments of the apparatus according to the invention.

Fig. 1 is a schematic view, not to scale, of a fireplace fitted with an apparatus for simulating a fire according to the invention, comprising LED's and a movable transparent plate disposed above said LED's;

Fig. 2 is a schematic, perspective view of an open fire fitted with an apparatus for simulating a fire according to the invention, in which the LED's are surrounded by a rotatable transparent cylinder comprising prisms.

[0022] In Fig. 1, numeral 1 indicates a printed circuit board on which a number of LED's 2 are arranged. The LED's are mainly amber-coloured, with a few red LED's here and there. The LED's are connected to one or more electronic processors 3, which control the LED's 2 according to a predetermined programme, both in an on/off mode and in an intensity-variation mode.

[0023] The light that is emitted by the LED's falls onto a transparent plate 4, which is disposed above said LED's and which is provided with protrusions 5, in the form of prisms in this embodiment, on the exit side thereof. Said protrusions 5 may also have other shapes besides prismatic shapes, they may for example be round or have a round shape provided with facets or any other shape.

[0024] The light beams, which exit the prisms 5 of the transparent plate 4 in broken form, are projected onto the rear wall 6 of a fireplace (schematically indicated). On said rear wall 6, a very true-to-nature imitation of a burning open fire is created, on the one hand because of the fact that the LED's 2 are controlled in a random order according to a predetermined programme, and on the other hand because of the fact that the light from said randomly controlled LED's travels through the transparent plate 4 and the protrusions 5 and falls onto the rear wall 6.

[0025] In order to further enhance the random nature of the light from the LED's, the transparent plate is movably disposed, and it is either moved forward and backward or moved in a specific pattern according to a predetermined programme. This mechanical movement further enhances the random character of the projection of the light onto the rear wall 6 of the fireplace. Since the light of the present apparatus is projected onto the rear wall 6 of the fireplace, the overall depth of the fireplace is less than that of known apparatuses, in which the light is projected to the front through a transparent plate.

[0026] Fig. 2 is a very schematic, perspective cut-away view, not to scale, of an embodiment of a fireplace fitted with an apparatus for simulating a fire according to the invention.

[0027] Numeral 1 again indicates a printed circuit board, on which a number of LED's are arranged in groups. The LED's of this embodiment, too, are mainly amber-coloured, with a few deep red LED's being present in several places.

[0028] The LED's are controlled by microprocessors 3, which turn the LED's on and off according to a predetermined programme, albeit in a very random manner, in which also the intensity and the brightness of the produced light are varied.

[0029] The printed circuit board 1 and the LED's 2 are surrounded by a cylinder 4 of a transparent material, which is externally provided with a large number of protrusions (not shown) in the form of prisms, similar to the plate 4 and the protrusions 5 of Fig. 1.

[0030] The cylinder 4 is mounted on a shaft 8, which is coupled to an electric motor (not shown), which is capable of rotating the cylinder. Disposed above the cylinder 4 is a shaft 9, on which a number of reflecting surfaces 10 are mounted, which shaft is fitted with a (friction) gear 11 which mates with a (friction) gear 12 on the shaft 8 of the cylinder 4.

[0031] In this way, both the cylinder 4 and the shaft 9 with the reflectors attached thereto rotate during operation, as a result of which the light from the LED's 12 is projected onto the rear wall 6 of the fireplace via the cylinder and the reflectors; in order to prevent the flames continuing too far up the rear wall, a plate 13 provided with a template 14 of flame forms is placed between the reflectors 10 and the rear wall.

[0032] This plate 13 intercepts flames that would continue far upwards in the fireplace, whilst the side of the plate 13 that faces towards the rear wall of the fireplace exhibits a pattern of flames, as a result of which the flame forms bear a greater resemblance to the natural flame form.

[0033] Surprisingly, it has become apparent that this relatively simple arrangement makes it possible to simulate a fire in a manner which closely resembles the image of flames of a natural wood fire.

[0034] Sound producing means may be added to the apparatus, which means imitate the sound of burning wood fire, with the sound that is produced by said means being synchronised with the programme that controls the LED's.

[0035] In this way, an apparatus is obtained which not only produces a true-to-nature image of a simulated wood fire, but which also produces sound that fits in with the produced image of flames in an optimally true-to-nature manner.

Claims

1. Apparatus for simulating a fire, in particular for use in a fireplace and the like, comprising a number of light-emitting diodes (LED's), which can be controlled and varied as regards intensity according to a predetermined programme, in which the emitted light beams can be projected onto a projecting surface via a diffuser, characterized in that at least one transparent plate is disposed between the LED's and the projection surface, which plate is provided with a pattern of protrusions on the light exit side thereof, which plate or plates and which LED's are movable with respect to each other during operation.

2. A simulation apparatus according to claim 1, characterized in that the transparent plate is a rotatable cylinder, which surrounds the LED's.

3. A simulation apparatus according to claim 1 or 2, characterized in that said protrusions are in the form of prisms.

4. A simulation apparatus according to claim 1, 2 or 3, characterized in that a number of reflecting surfaces are arranged on the light exit side of the transparent plate, which surfaces include mutually different angles with each other and which project the exiting light onto the projection surface.

5. A simulation apparatus according to claim 4, characterized in that said reflecting surfaces are movably disposed with respect to the LED's and the transparent plate.

6. A simulation apparatus according to claim 5, characterized in that the reflecting surfaces are formed of a number of strips of a reflecting material, which are arranged on a rotatable shaft.

7. A simulation apparatus according to any one or more of the preceding claims, characterized in that the LED's have different colours.

8. A simulation apparatus according to claim 5 or 6, characterized in that the reflecting surfaces have different colours.

9. A fireplace comprising an apparatus for simulating a fire according to any one or more of the preceding claims, characterized in that the LED's are arranged on one or more printed circuit boards extending in the transverse direction of the fireplace, and wherein the transparent plate and the reflecting surfaces are so arranged that the light can be projected onto the rear wall of the fireplace.

10. A fireplace according to claim 9, characterized in that a cover plate is disposed above the cylinder-shaped transparent plate, which cover plate limits the height of the flame and which is provided with a template of flame forms on the side that faces towards the rear wall.

11. A fireplace according to claim 9, characterized in that said fireplace includes programmable means for producing a sound simulating a burning wood fire, with means being present for synchronising the control programme of the LED's and the means for producing the sound.

Drawing