GB2563248A

GB2563248A - Visual effect device

Info

Publication number: GB2563248A
Application number: GB1709078.8A
Authority: GB
Inventors: James Turner Mark
Original assignee: Mtfx Ltd
Current assignee: Mtfx Ltd
Priority date: 2017-06-07
Filing date: 2017-06-07
Publication date: 2018-12-12
Also published as: GB201709078D0; GB2577460A; WO2018224435A1; GB202000140D0

Abstract

A visual effect device, especially for using pyrotechnics for producing the effect of falling snow/ash, where the device includes a holder for holding a sublimable solid for heating, a powered heater for heating the sublimable solid to a particular temperature and a connector for supplying power to the heater. The device may also include a controllable fan. The sublimable solid may be metaldehyde or hexamethylenetetramine.

Description

Visual Effect Device

The present invention relates to visual effect devices especially for generating a falling snow and/or ash visual effect. The invention also relates to methods for generating a visual effect, especially a snow and/or ash visual effect, using such devices.

It is known to produce a visual/special effect, useful for film and television and live events, of falling snow or ash using pyrotechnics containing the solid fuel metaldehyde. In such pyrotechnics, the metaldehyde does not burn completely. Instead, the flame of the pyrotechnic heats metaldehyde and produces particulates by a process of sublimation. Such pyrotechnics are often known as snow candles. GB-A-2,502,459 discloses a pyrotechnic device especially as an indoor firework with a tablet including metaldehyde, hexamethylenetetramine, or an oxime and a material (e.g. iron etc) which produces sparks during combustion. GB-A-2,153,809 discloses a pyrotechnic composition for the production of flashes of light with metaldehyde and hexamethylenetetramine which burns without smoke and which deflagrates in the manner of a lightning flash. GB-A-1,405,230 discloses a decorative candle composed of metaldehyde as the fuel and a metal compound as colourant. The aim of the invention is complete and even combustion. JP-A-H101 684 81 discloses a special effect candle with sparkler effect using a mixture of magnesium and metaldehyde. CN-A-105 175 200 discloses a pyrotechnic composition for calligraphy, the composition comprising metaldehyde with ammonium perchlorate, colourant (copper chloride) and binder.

However, a problem with such known methods is that the production of the falling snow/ash visual effect is difficult to control, both the volume of the effect, turning the effect on and off and directing the effect. Furthermore, for many productions, a large number of pyrotechnics are required to give a convincing effect. This can lead to stocking problems and the safety issues of stocking large numbers of pyrotechnics. Furthermore, pyrotechnics generate smoke, occasionally in large quantities, which may be slow to disperse and may adversely affect the visual effect during production.

There is, therefore, a need for a more controllable and convenient means of providing such visual effects.

It is an aim of the present invention to address this need.

The present invention accordingly provides, in a first aspect, a visual effect device, the device comprising a holder, the holder being adapted to hold a sublimable solid for heating, a powered heater for heating the sublimable solid to a temperature in a predetermined range, and a connector for supplying power to the heater.

Preferably, the device is for generating a snow and/or ash visual effect, preferably a falling snow and/or ash visual effect using the sublimable solid.

The device may be arranged so that the sublimable solid may be pressed against a hot surface of the heater during heating. This may be achieved by the device being arranged so that the holder (containing, in use, the sublimable solid) may be pressed against the hot surface during heating. This is advantageous because it improves thermal contact between the heater (and specifically the heatable surface of the heater) and the holder and/or between the heater and the sublimable solid, in use, thereby improving the control and efficiency of the generation of the visual effect. It is thought, without wishing to be bound, that pressing the sublimable solid towards the heater improves thermal contact by overcoming the insulating effect resulting from a barrier of sublimed gas between the hot surface and the bulk of the sublimable solid.

The holder and/or sublimable solid may be pressed against the heated surface of the heater by a pressing mechanism. The pressing mechanism may comprise a weight or a resilient mechanism. Preferably, such a resilient mechanism comprises a spring, optionally a leaf spring.

In some embodiments, the device may further comprise a casing and/or may further comprise a gas inlet for flowing gas over the sublimable solid, in use. Usually, the gas inlet will allow gas to flow to the holder. Controlled gas flow enables further control over the sublimation process thereby allowing more control over the visual effect.

In use, the sublimed vapour/gas from the sublimable solid may flow from the device thereby allowing the device to generate the effect of falling snow/ash.

The powered heater may comprise a hot gas blower for supplying heated gas to the sublimable solids/holder or to the gas inlet, if present. The hot gas blower preferably comprises a controllable hot gas blower to supply gas at a controllable temperature and/or controllable flow rate.

Whether or not the powered heater comprises a hot gas blower, it is advantageous if the device further comprises a fan for supplying gas over the sublimable solid, (e.g. to the holder) or into the gas inlet, if present. The fan is preferably a controllable fan to supply gas at a predetermined flow rate. This is beneficial because it allows for greater control of the visual effect.

Preferably, the powered heater is an electrical heater. In the alternative, the powered heater may be gas-powered.

The heating effect provided by the heater will usually be due to thermal conduction and may be at least be partly radiative or convective. Thermal conduction heating may be between a hot surface of the heater and the holder/sublimable solid. Convective heating may include heating by blowing hot air over the holder/sublimable solid.

The heater may comprise at least one hotplate having one or, possibly, two hot surfaces. A hotplate having two heatable surfaces may be in the form of a heater with a heatable blade, both sides of which are heatable. The device may include a part for receiving and holding the heater (i.e. a heater seat) and/or may include a part allowing insertion or connection of the heater (i.e. a heater port for receiving the heater).

The predetermined temperature range depends upon the nature of the sublimable solid, the atmospheric conditions (e.g. air temperature, air pressure and wind speed, especially when outside) and will usually be in the range 105°C to 350°C (or 103°C to 353°C), preferably 120°C to 320°C (or 119°C to 323°C, more preferably 130°C to 300°C (or 129°C to 302°C), most preferably 140°C to 290°C (or 139°C to 292°C).

In use, the device will further comprise the sublimable solid. Usually, the sublimable solid will comprise one or more shaped blocks. The shaped blocks may be in the shape of a pellet, a block with one or more peripheral cut-outs and/or a block with one or more holes. The blocks may be hollow solids having a central hole and a periphery that in cross-section may be circular, polygonal and/or crenallated, scalloped or with cut-outs. Holes in the shaped blocks may be (in plan/cross-section) circular, star shaped (with 3, 4, 5, 6, 7, 8, 9, 10 arms), cross-shaped, scalloped or crenallated. The advantage of using shaped blocks is to further control the sublimation process, especially over time of heating.

The sublimable solid may comprise metaldehyde, hexamethylenetetramine, other sublimable compositions and/or a mixture thereof.

The casing of the device, if present, may be generally cylindrical.

The device may further comprise one or more fixings to fix a lanyard to the device, usually to the casing if present. This is advantageous because fixings enable the device to be swung or spun on a lanyard, generating relative air-flow over the outlet and producing various visual effects of falling snow and/or ash as the solid sublimes.

Preferably, the device is substantially portable, more preferably hand portable.

Use of the device with a sublimable solid enables a visual effect of falling snow and/or ash to be produced.

Thus, in a second aspect, the present invention provides, a method for generating a visual effect, the method comprising, providing a device according to the first aspect, placing a sublimable solid in the holder of the device, and supplying power to the heater thereby heating the sublimable solid to a temperature in the predetermined range.

The method may further comprise pressing the sublimable solid and/or holder against a heated surface of the heater during heating of the sublimable solid, thereby improving thermal contact.

Preferably, the device comprises a gas inlet and the method further comprises supplying flowing gas to sublimable solid/holder and/or into the gas inlet, if present.

Preferred and advantages features of the first aspect, as described above, are also preferred and advantageous of the second aspect.

Embodiments of the present invention will now be described with reference to the following figures, in which:

Figure 1 is perspective view of an embodiment of a visual effect device according to the invention.

Figure 2(a) is a partially exploded perspective view and (b) a top plan view of a second embodiment of a visual effect device according to the invention.

Figure 3 is a schematic partial cross-sectional view of a third embodiment of a visual effect device according to the invention.

Figure 4(a) is a schematic perspective view of a fourth embodiment of a visual effect device according to the invention; and (b) is a schematic top plan view of the device.

Figure 5(a) to (i) are schematic plan views of shapes of blocks of sublimable solids for use in the device of Figure 3, Figure or Figure 2.

Figure 1 illustrates a device 2 according to an embodiment of the invention for producing a visual effect. The device 2 comprises a generally squat hollow cylindrical casing 4, a base plate 6 and an outlet 9 in the form of the open top of the hollow of the casing 4. The hollow part of the casing 4 provides holder 10 for receiving and holding a sublimable solid composed of, for example, metaldehyde or hexamethylenetetramine (not shown in Figure 1).

The base plate 6 incorporates a heater (not shown in Figure 1) in the form of a hotplate extending substantially over the base area of the holder 10. Power to the hotplate heater is supplied through heater power supply 8. The heater controllably heats the holder 10 and thus the sublimable solid (in use) to a sufficient temperature for the solid to sublime. The sufficient temperature depends on the nature of the solid, atmospheric conditions (for example air pressure and wind speed when outside) and the type of effect required. Generally, the temperature range is around 105 °C to 320 °C. The subliming solid flows from the outlet 9 and gives the effect of falling snow or ash.

In an alternative, the heater may be in the form of types of heating element other than a hotplate located in the base plate and/or in the casing 4. The heater may be electrical or may be gas-powered (in which case the heater power supply 8 may be a flammable gas inlet). The heating effect will usually be due to thermal conduction between the hotplate (or other heater surface) and the holder/sublimable solid and may be at least be partly radiative or convective (that mat be enhanced, for example, by blowing hot air over the holder/sublimable solid).

The device 2 has fixings 11 for fixing lanyards (not shown) to the device 2. Such fixings 11 and lanyards enable the device to be swung or spun generating relative air-flow over the outlet 9 and producing various visual effects of falling snow or ash as the solid sublimes.

Figure 2 illustrates in partially exploded perspective view (a) and top plan view (b), a device 12 according to another embodiment of the invention for producing a visual effect. The device 12 comprises a generally elongate hollow cylindrical casing 14, a heater seat 16 inside the casing 14 and an outlet 19 in the form of the open top of the hollow in the casing 14. The hollow part of the casing 14 provides holder 20 for receiving and holding a sublimable solid of, for example, metaldehyde or hexamethylenetetramine (not shown).

The heater seat 16 has a heater port 17 in the base for receiving the blade 24 of an electrical blade heater 22. Power to the blade heater 22 is supplied through heater power supply 18. The heater 22 controllably heats the holder 20 and thus the sublimable solid (in use) to a sufficient temperature for the solid to sublime. The sufficient temperature depends on the nature of the solid, atmospheric conditions (for example air pressure and wind speed when outside) and the type of effect required. Generally, the temperature range is 120 °C to 320 °C. The subliming solid flows from the outlet 19 and gives the effect of falling snow or ash.

The device 12 has a gas inlet 26 for supplying flowing gas (usually air) to the holder and thus over the sublimable solid. This enables the use of a controlled air flow to further control the properties of the sublimable solid as it sublimes. Gas may be supplied using a fan (not shown), preferably a controllable fan, connected to the gas inlet 26. The fan may provide air/gas at ambient temperature or may provide heated air/gas depending on the intended use of the device 12.

The sublimable solid when inserted in the holder 20 may be pressed against the heated surface by a pressing mechanism (not shown in Figure 2) that may be a resilient mechanism (for example, a spring) or a weight (for example, an elongate weight) arranged to be inserted in the holder on the sublimable solid.

As in the embodiment shown in Figure 1, as an alternative, the heater may be in the form of types of heating element other than a blade heater located in the heater seat 16 and/or in the casing 14. The heater may thus be electrical or may be gas-powered. The heating effect will usually be due to thermal conduction between the hotplate (or other heater) and the holder/sublimable solid and may be at least be partly radiative or convective (for example by air over the holder/sublimable solid as discussed above in relation to gas inlet 26, the air being heated).

The properties of the solid as it sublimes may be affected by the geometry of the sublimable solid. Often, the sublimable solid will be in the form of multiple (i.e. two or more) pellets. Alternatively, the sublimable solid may be in the form of one or more shaped blocks, shaped so as to control the sublimation process.

Figure 3 illustrates in perspective view a third embodiment of a visual effect device according to the present invention. The device 32 comprises a heater 42 in the form of a hotplate having a heater power supply 38 and a heatable surface 44. Sublimable solid in the form of pellets 52 are contained in a holder 40 on the heatable surface 44. A leaf spring 46 is so mounted on the heater 42 using a spring mount 48 and mounting bolt 50 that it exerts a force that presses the holder 40 (and hence sublimable solid pellets 52) against the heatable surface improving thermal contact, in use.

Figure 4 (a) and (b) are schematic perspective and top plan views respectively of a fourth embodiment of a visual effect device according to the invention. The device 62 comprises a generally cylindrical hollow casing 64 inside of which is mounted a holder 72 by holder mounts 74 fixed to the casing 64. The holder contains pellets 76 of sublimable solid, for example, metaldehyde or hexamethylenetetramine. There is, in this device 62, no hotplate heater, instead a hot air blower 68 with power supply 70, provides flowing heated air into the device 62 through air/gas inlet 66 and hence over the holder 72 and pellets 76. The hot air blower 68 is controllable so that the temperature and flow rate of the hot air may be controlled.

Figure 5 illustrates in plan view (and this would also be the sectional view of these blocks) some possible shaped blocks 101, 201. Generally, the blocks may be a hollow solids having a generally central hole 116, 204 and a periphery that may be circular, polygonal, star-shaped and/or crenallated, scalloped or with cut-outs.

Figure 5, (a) to (f) show blocks 101 that may be suitable for the device 12 illustrated in Figure 2 with a central hole 116 so they may be received on the heater seat 16. Figure 3(a), (b), (c) and (e) have one or more peripheral cut-outs 104 to allow improved air/gas flow from the gas inlet in the device over the sublimable solid 102.

Figure 5, (g) to (i) show blocks 201 that may be suitable for the device 2 illustrated in Figure 1. Figure 5(g), (h), and (i) have generally central holes 204 of various shapes (cross (g), scalloped square (h) and 8-pointed star (i)) to allow more controllable and efficient sublimation with time of the sublimable solid 202.

Reference Numerals 2 device 4 casing 6 base plate 8 heater power supply 9 outlet 10 holder 11 fixing 12 device 14 casing 16 heater seat 17 heater port 18 heater power supply 19 outlet 20 holder 22 blade heater 24 blade hotplate 26 gas inlet 32 device 38 heater power supply 40 holder 42 heater 44 heatable surface 46 leaf spring 48 spring mount 50 mounting bolt 52 pellets of sublimable solid 62 device 64 casing 66 air inlet 68 hot air blower 70 hot air blower power supply 72 holder 74 holder mount 76 pellets of sublimable solid 101 shaped block of sublimable solid 102 sublimable solid 104 peripheral cut out 116 hole in block 201 shaped block of sublimable solid 202 sublimable solid 204 hole in block

Claims

1. A visual effect device, the device comprising a holder, the holder being adapted to hold a sublimable solid for heating, a powered heater for heating the sublimable solid to a temperature in a predetermined range, and a connector for supplying power to the heater.

2. A device as claimed in claim 1, wherein the device is for generating a snow/ash visual effect, preferably a falling snow/ash visual effect.

3. A device as claimed in either claim 1 or claim 2, wherein the device is arranged so that the sublimable solid may be pressed against a heated surface of the heater during heating.

4. A device as claimed in claim 3, wherein the device is arranged so that the holder may be pressed against a heated surface of the heater during heating.

5. A device as claimed in claim 3 or claim 4, wherein holder and/or sublimable solid may be pressed against the heated surface of the heater by a pressing mechanism.

6. A device as claimed in claim 5, wherein the pressing mechanism comprises a weight or a resilient mechanism.

7. A device as claimed in claim 6, wherein the resilient mechanism comprises a spring, optionally a leaf spring.

8. A device as claimed in any one of the preceding claims, further comprising a casing.

9. A device as claimed in any one of the preceding claims, further comprising a gas inlet for flowing gas over the sublimable solid, in use.

10. A device as claimed in claim 9, wherein the powered heater comprises a hot gas blower for supplying heated gas to the gas inlet, preferably a controllable hot gas blower to supply gas at a controllable temperature and/or controllable flow rate.

11. A device as claimed in either claim 9 or claim 10, further comprising a fan for supplying gas to the gas inlet, preferably a controllable fan to supply gas at a controllable flow rate.

12. A device as claimed in any one of the preceding claims, wherein the powered heater is an electrical heater.

13. A device as claimed in any one of the preceding claims, wherein the heater comprises a at least one hotplate.

14. A device as claimed in any one of the preceding claims, wherein the predetermined temperature range is 105°C to 350°C, preferably 120°C to 320°C, more preferably 130°C to 300°C, most preferably 140°C to 290°C.

15. A device as claimed in any one ol the preceding claims, further comprising sublimable solid in the holder.

16. A device as claimed in claim 15, wherein the sublimable solid comprises one or more shaped blocks.

17. A device as claimed in claim 16, wherein the shaped block is in the shape of a pellet, a block with one or more peripheral cut-outs and/or a block with one or more holes.

18. A device as claimed in any one of the preceding claims, wherein the sublimable solid comprises metaldehyde, hexamethylenetetramine, other sublimable compositions and/or a mixture thereof.

19. A device as claimed in any one of the preceding claims, further comprising one or more fixings to fix a lanyard to the device.

20. A device as claimed in any one of the preceding claims, wherein the device is substantially portable, preferably hand portable.

21. A method for generating a visual effect, the method comprising, providing a device as claimed in any one of the preceding claims, placing a sublimable solid in the holder of the device, and supplying power to the heater thereby heating the sublimable solid to a temperature in the predetermined range.

22. A method as claimed in claim 20, the method further comprising pressing the sublimable solid and/or holder against a heated surface of the heater during heating of the sublimable solid.

23. A method as claimed in either claim 20 or claim 21, wherein the method further comprises supplying flowing gas so that it passes over the sublimable solid.

24. A method as claimed in claim 22, wherein the device comprises a gas inlet for the supply of flowing gas.