WO2010139996A1

WO2010139996A1 - Chemical vaporiser for use with a candle

Info

Publication number: WO2010139996A1
Application number: PCT/GB2010/050931
Authority: WO
Inventors: Ron Jones; Roy Price
Original assignee: Vapalight Limited
Priority date: 2009-06-03
Filing date: 2010-06-03
Publication date: 2010-12-09
Also published as: GB0909530D0

Abstract

The invention relates to a chemical vaporiser adapted for use with a candle to vaporise a volatile chemical such as a fragrant chemical or an insecticide such as pyrethrum. The chemical vapouriser comprises a base and a cradle spaced from the base, the cradle being arranged to receive a chemical reservoir. The cradle may have a central aperture through which a flame from the candle can pass. In use with candle having a top and an outer periphery of the top the top the base of the chemical vapouriser is within the outer periphery. As the candle burns the chemical vapouriser moves downward with the top of the candle maintaining the chemical reservoir a constant distance from the flame.

Description

CHEMICAL VAPORISER FOR USE WITH A CANDLE

This invention relates to a chemical vaporiser adapted for use with a candle to vaporise a volatile chemical such as a fragrant chemical or an insecticide such as pyrethrum.

It is known to incorporate insecticides such as pyrethrum and scented oils/chemicals into wax and to use the wax for candles. As the candle burns the scented chemical or pyrethrum is released into the surrounding area. In the case of scented chemicals this produces a pleasing ambience. If an insecticide is used the vaporised insecticide can discourage or kill insects such as mosquitoes.

It has been realised that it is desirable to suppress the number of mosquitoes in or near human habitation in areas of the world that have malaria in order to reduce the number of occasions on which mosquitoes bite humans so reducing the risk of transmission of malaria.

According to a first aspect of the invention there is provided a chemical vaporiser for use with a candle, the chemical vaporiser comprising: a base having an aperture; a cradle adapted to support a reservoir of chemical to be vaporised in use; a spacing portion extending in a first direction from the base and connecting the cradle to the base; and wherein the base has a candle engaging means extending in a second direction generally opposite to the first direction.

In a preferred embodiment the candle engaging means comprises at least one spike. In a more preferred embodiment the candle engaging means comprises two spikes preferably located on opposing sides of the base. Alternative candle engaging means may also be employed such as a screw thread or a pinion arranged to engage the candle.

An advantage of such a chemical vaporiser is that the vaporiser sits on an upper surface of the candle and preferably at least the base is within an outer periphery, allowing the vaporiser to be used on candles having different diameters and having varying outer peripheries. This is a distinct advantage over devices known as candle followers in which a portion of the follower sits over the upper surface and a depending portion of the follower extends around the outer periphery of the candle. With these devices candles of differing diameters require followers of varying diameters adapted to fit to the candle. In contrast in the chemical vapouriser according to the invention the vapouriser can be used with candles of varying diameters.

The candle is preferably of the kind known as a pillar candle in which the candle has relatively wide column. Such candles generally burn so as to form an outer periphery of un-melted wax. A wick is provided at the top of the candle.

The vaporiser may also be used with container candles provided that the base and cradle are sized to fit within a periphery of a top of the candle. In a particularly preferred embodiment the vapouriser may be used in combination with a container candle of the kind having a cylindrical container. Such a container may be fireproof and may provide a shield for the flame of the candle. The container may have a removable lid. The candle may be provided with a pre-moulded recess adapted to receive the base of the chemical vapouriser.

Preferably the base of the vapouriser comprises a circular base having an aperture arranged to pass over a wick of the candle in use. The base may have a width and an outer diameter. Preferably a width of the base may be selected to provide stability to the chemical vaporiser. The width may vary from lmm to 400mm. More preferably the width may vary between lmm and 300mm. It is envisaged that in most preferred embodiments the width may vary between 2mm and 100mm. More preferably the width is from 2mm to 25mm and in a most preferred embodiment the width may be from 5mm to 10mm. The outer diameter of the base may be selected such that the base rests in a pool of melted wax when the vaporiser is in use on a candle. The outer diameter may be from 10mm to 400mm or more preferably from 15mm to 300mm. A preferred diameter is from 20mm to 150mm and a most preferred diameter is from 40mm to 100mm.

It has been found that an unexpected advantage of the vapouriser is that a burn time of the candle is significantly prolonged by use of the vapouriser. It has been found that the burn time may be extended by 25% to 50% of the expected burn time for a given candle. For example a candle having a described burn time of 30 hours has been found to have a burn time of over 40hours when the chemical vapouriser is used. The extension of the burn time has been found to occur with pillar and container candles.

The spacing portion is connected between the base and the cradle and may comprise a single arm. Preferably the spacing portion comprises at least two arms and may in some embodiments comprise three or four or more arms. The or each arm may be vertically orientated. The or each arm may be substantially straight or may be curved or angled.

In one preferred embodiment the outer diameter of the base is smaller than an outer diameter of the cradle. Alternatively the outer diameter of the base may be larger than the outer diameter of the cradle or the base and the cradle may have substantially the same outer diameter. In a preferred embodiment the spacing portion comprises two arms arranged on opposing locations on the base and connected to corresponding opposing locations on the cradle. The arms allow passage of air to the flame of the candle facilitating a steady and even burning of the candle.

In an alternative embodiment the spacing portion may comprise a shielding envelope connected between the base and the cradle. The envelope may be arranged to allow the passage of air to the candle flame but may be arranged to shield the flame from drafts. The shielding envelope may be arranged to be supported on the base and may carry the cradle.

The cradle may comprise a laminar plate. Preferably the laminar plate is provided with an aperture substantially centrally located in the plate. The aperture may be located and the spacing portion arranged such that in use the flame of the candle passes through the aperture.

According to a second aspect of the invention there is provided in combination a chemical vaporiser according to the first aspect of the invention and a reservoir of a chemical to be vaporised.

In one embodiment the reservoir of the chemical to be vaporised comprises a ceramic disc containing a volatile chemical. The ceramic disc may comprise a ceramic formed of a sintered glass. Preferably the ceramic comprises a material having rounded grains.

Preferably the disc may be placed on the laminar plate. In an alternative embodiment the laminar plate may be arranged to positively locate the disc. Alternative forms of reservoir may be utilised. In one embodiment the reservoir may be in the form of an annular ring arranged to be able to sit on the cradle.

In an alternative embodiment the chemical to be vaporised may be provided in a container comprising a compartment containing chemical to be vaporised and a vaporisation chamber. Preferably the container may be arranged to be supported by or to engage with the cradle. The chemical in the compartment may be in a liquid or a solid form. Suitable vaporising means may be provided.

According to a third aspect of the invention there is provided a kit suitable for dispersing insects comprising a candle a chemical vaporiser according to a first aspect of the invention and a reservoir of chemical to be vaporised.

According to a another aspect of the invention A kit suitable for dispersing insects comprising a candle having a top and an outer periphery of the top; a chemical vaporiser having a base with an aperture, the base being arranged and adapted to be supported on the top of the candle in use and entirely within the outer periphery of the top; a cradle adapted to support a reservoir of chemical to be vaporised in use; a spacing portion extending in a first direction from the base and connecting the cradle to the base; and a reservoir of chemical to be vaporised.

In one embodiment the candle may be provided with a pre-moulded recess in the candle. The recess is sized to accept the base of the chemical vapouriser and may improve stability of the chemical vapouriser as the candle burns.

According to a fourth aspect of the invention a method of dispersing insects comprises placing a chemical vaporiser according to the first aspect of the invention onto a candle, locating a reservoir of chemical to be vaporised on the chemical vaporiser and lighting the candle.

Preferably the chemical to be vaporised comprises pyrethrum. Alternatively the chemical to be vaporised may comprise piperonyl butoxide. The chemical to be vapourised may be a composition comprising pyrethrum and piperonyl butoxide. A suitable buffer solution may also be used. The buffer solution may be used to control the evaporation rate of the active ingredient. Other insect repellent chemicals may be used or suitable combinations of chemicals may be used.

As the candle burns the chemical vaporiser positions the reservoir of chemical to be vaporised at a distance from the candle flame such that the flame heats the reservoir of chemical and causes the chemical to vaporise. As the candle burns, the flame melts wax around a wick of the candle and forms a pool of liquid wax. The base of the chemical vaporiser rests on an upper surface of the candle and preferably within the pool of liquid wax. As the candle burns down the chemical vaporiser moves with the candle and the cradle is maintained at a substantially constant distance from the flame such that a substantially steady heat is provided to the source of chemical to be vaporised.

The size of the candle and the wick size and material may be varied in order to control the length of time for which the candle burns. The size and material of the wick may also be varied so as to control the heat output of the flame. According to a fifth aspect of the invention there is provided a method of vaporising a fragrant chemical comprising placing a chemical vaporiser according to the first aspect of the invention onto a candle, locating a source of the fragrant chemical to be vaporised on the chemical vaporiser and lighting the candle.

A chemical vaporiser for use with a candle having a top and an outer periphery of the top may comprise: a base arranged and adapted to be supported on the top of the candle in use and entirely within the outer periphery of the top; a cradle; a spacing portion connected between base and the cradle and arranged to space the cradle from the base, wherein the cradle is arranged to support a reservoir of chemical to be vaporised.

The invention will now be further described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a chemical vaporiser in accordance with the invention;

Figure 2 is a cross section of the chemical vaporiser of Figure 1 ;

Figure 3 is a cross section of an alternative embodiment of the invention;

Figure 4 is a perspective view of an embodiment of the invention in use on a candle; Figure 5 is a perspective view of one form of a reservoir of chemical to be vaporised;

Figure 6 is a perspective view of an alternative reservoir of chemical to be vaporised;

Figure 7 is a cross section of the cradle of the invention adapted for use with a reservoir as illustrated in Figure 5 and

Figure 8 is a cross section of a cradle adapted for use with one or more reservoirs as illustrated in Figure 6.

Figure 9 is a cross section of a chemical vapouriser in combination with a cylindrical container.

Figure 1 illustrates a chemical vaporiser 1 in accordance with the first aspect of the invention and comprising a base 2 and a cradle 4 connected to the base 2 by means of a spacing portion 6 which in this embodiment comprises a first arm 8 and a second arm 10. The base 2 is in the form of a ring formed of metal. The ring is relatively narrow in width. The arms 8 and 10 comprise rods angled outwardly and upwardly in a first direction from the base and connected at an upper portion to the cradle 4. The arms 8 and 10 are bent or curved towards a vertical orientation before connection to the cradle.

The base is also provided with two spikes 12 arranged on opposing sides of the base and projecting in a second direction generally opposing the first direction in which the arms 8 and 10 extend. In use the spikes 12 can be inserted into a candle to locate and secure the base to the candle. In this embodiment the cradle comprises a wall 14 having an outer surface 16 to which the arms are connected. A lower portion of the wall 14 is joined to an inwardly extending laminar plate 18 having a centrally located aperture 20. The aperture is sized such that a flame of a candle may pass through the aperture. A size of the aperture may be varied depending on the size of the flame and the heat generated by the flame.

A reservoir of chemical to be vaporised can be located on the cradle. The reservoir may simply be placed on the cradle. In other embodiments the cradle may be adapted to positively locate the reservoir.

Figure 2 is a cross section of the chemical vaporiser of Figure 1 and the arms 8 and 10 can be seen to be joined to the outer surface 16 of the walll4. The laminar plate 22 is integrally formed with the wall 14. It will be understood that the laminar plate may be formed separately and joined to the wall 14.

A cross section of an alternative embodiment of a chemical vaporiser is shown in Figure 3. In this embodiment the base is similar to that of Figure 1. The spacing portion comprises two arms 8 and 10 as before. In this embodiment the cradle simply comprises a laminar plate 22 having an aperture 20. The arms 8 and 10 are connected to an edge 24 of the laminar plate. A width 26 of the plate 22 may be varied so as to be able to support a reservoir of a chemical to be vaporised. The width is preferably around 5mm but the exact width may be varied depending on the size of the reservoir required for the evaporation period.

Figure 4 shows a chemical vapouriser in use on a candle 28 and use of an embodiment of the invention will now be described. The chemical vapouriser is placed on an upper surface 30 the candle 28 such that the base 2 is located around a wick 32 of the candle. The arms 8 and 10 extend upwardly and outwardly from the base to the cradle 4. A reservoir (to be described in more detail below) of a chemical to be vaporised is placed on the cradle. In the embodiment illustrated in Figure 4 the reservoir may be simply placed on the laminar plate 18. It is preferred that the upper surface of the candle is substantially planar and of the kind found in pillar candles rather than being outwardly and downwardly inclined as is usually the case with taper candles.

The base 2 is sized such that the base is entirely within an outer periphery 34 of the candle with which the vaporiser is to be used. Once the vaporiser is positioned over the wick and the reservoir is placed on the cradle the wick 32 is lit and a flame forms which passes through the aperture 20 of the cradle. Heat from the flame is transmitted to the reservoir and heats the chemical to be vaporised so releasing vapour to the atmosphere. As the candle burns wax from the candle melts and forms a pool 36 of melted wax around the wick and over the base 2. The base 2 is close enough to the wick to be within the pool of melted wax and as the candle burns down the chemical dispenser moves with the wick. Thus the cradle is maintained at a constant distance from the flame and a steady heat is transmitted to the reservoir.

As can be seen in Figure 4, the candle is of the type known as a pillar candle having a relatively wide diameter. As the candle burns down a ring 38 of unmelted wax is formed around the periphery of the candle. The base of the chemical vapouriser is narrower than the ring of unmelted wax. The outer diameter of the cradle is also smaller than an internal diameter of the un-melted ring of wax 38 such that the cradle can move downwards as the candle burns without interference with the ring 38 of wax. A reservoir of chemical to be vaporised will now be described in more detail. Figure 5 illustrates a ceramic reservoir 40 shaped in the form of a ring and sized to be supportable by the cradle. The reservoir 40 is annular and has an aperture 42 of the same size as the aperture 20 of the cradle. A height 44 of the reservoir 40 is substantially the same as that of the wall 14 of the cradle. It will be appreciated that the height 44 of the reservoir may be increased and that such a larger reservoir may contain more chemical to be vaporised.

An alternative reservoir 50 is illustrated in Figure 6. In this embodiment the reservoir comprises a disc of ceramic material. The disc 50 has a diameter 52 such that the disc may be placed on the laminar plate 18. A number of discs may be placed ion the laminar plate at the same time or it may be more desirable to only place a single disc at a time on the plate 18. A depth or height of the disc may also be increased in order to increase the capacity of the reservoir.

The reservoirs 40 and 50 described above are made of a ceramic material, and preferably a sintered glass material.

A number of ceramic materials have been investigated for their suitability as the chemical reservoir. Of these a number of sintered ceramics have been found to be particularly effective. Coralith TM C5 available from Fairey Filtration Systems and Alumina A12 from Ceram Tec, have been found to be a suitable ceramics together with traditional sintered glass and to provide suitable retention of chemicals to be vaporised.

These ceramics are alumina glasses or borosilicate glass ceramics. Suitable examples are sintered glasses used in filtering and glasses such as PyrexTM and DuranTM. Other materials may also be suitable. Investigation and experimentation has shown that a suitable ceramic must have a number of characteristics. In particular it has been found that the ceramic should have a grain size that is substantially homogeneous and that finer and coarser grains should be removed from the ceramic material. A grain size in the region of 20 to 400 microns has been used. One suitable ceramic has a grain size in the region of 40 to 80 microns while other suitable ceramics have a grain size between 200 and 400 microns and 200 to 300 microns in particular. Particles between 0.1 and lOOμm may be used depending on the properties of the volatile substance.

It is also advantageous for the ceramic to comprise grains that have rounded edges. This may be achieved by sintering the ceramic as in sintered glass or by otherwise annealing the ceramic.

The ceramic should also have a relatively narrow range of pore diameters and preferred materials have pore diameters in the range of 10 to 100 microns. One particularly suitable material has been found to have pore diameters in the range of 10 to 20 microns while another suitable material has pore diameters in the range 20 to 30 microns.

Overall porosity of the ceramic varies with the pore size distribution. It is desirable that the overall porosity is selected such that the burn off time of the volatile chemical is prolonged. If the burn off is too rapid then the volatile chemical is dispersed too quickly. The burn off period increases with the porosity so in general a higher porosity ceramic will increase the burn off period. The exact preferred porosity may vary with the volatile chemical and carrier oil utilised. Porosity values from 10% to 80% have been used depending on the chemical and carrier oil. In general though a porosity in the region of 20 to 50% has been found to provide suitable burn off periods and a particularly desired range is 30 to 40% porosity. Sintered glass having an overall porosity of around 35% by volume may be formed from a thermal, shock-resistant borosilicate glass such as Pyrex or Duran.

Preferably the material of the chemical carrying element is non reactive with the chemical to be vaporised.

The chemical to be vaporised may comprise pyrethrum. Alternatively or in addition the chemical may comprise piperonyl butoxide. A suitable buffer solution may also be used to control the evaporation rates. It is envisaged that other insect repellent chemicals can be used in addition or in combination.

Figures 7 and 8 are cross sections of alternative forms of laminar plate. In Figure 7 the laminar plate of the cradle has an internal wall 70 extending around the aperture 20 in the plate 18. The internal wall acts with the wall 14 to positively locate a reservoir in the form of an annular ring on the cradle.

In Figure 8 the laminar plate is provided with recesses 80 arranged to receive a portion of the reservoirs in the form of discs 50.

As has been described above the chemical vaporiser can be used with candles of different sizes since the base sits on an upper surface and within an outer periphery of the candle. The base of the vaporiser moves with the candle maintaining the reservoir of chemical to be vaporised at a constant distance from the flame and providing a steady vaporisation of the chemical throughout the burning period of the candle or until all the chemical in the reservoir has been vaporised. Figure 9 is a cross section of a chemical vapouriser in combination with a cylindrical container. In this embodiment a candle 90 is provided in a container 92. A wick 94 extends from a base 96 of the container. In this embodiment the container is fireproof or fire resistant. A chemical vapouriser 98 is placed on a top 100 of the candle. A base 102 of the chemical vapouriser 98 rests on the top of the candle and melted wax 104 flows over the base 102. Two arms 106 extend upwards from the base on either side of the base. In this case the arms have a first portion 108 angled upwardly and outwardly and a second upwardly extending portion 110 that connects to a cradle 112. The cradle and the arms are dimensioned so as to fit with in the cylindrical container. The cradle has an inwardly extending laminar surface 114 and a central aperture 116 through which a flame of the candle can extend. A chemical reservoir as previously described can be placed on the laminar surface and is can be in the form of an annular disc.

As the candle burns the top 100 of the candle moves down the container and the base 102 of the chemical vapouriser moves downward with the candle. The arms and cradle fit within the container and can slide down within the container so that the chemical reservoir is maintained at a constant distance from the flame. The container 92 stabilises any lateral movement of the chemical vapouriser and it has been found that the provision of a candle engaging means such as spikes or pinions is not necessary in this embodiment. Additionally it has been found that the burn time of a candle in a container is significantly prolonged with the addition of the chemical vapouriser, so providing an improvement in the efficiency of the candle. For example a candle described as having a burn time of 25 to 30 hours has been found to burn for a period of 40 hours or more. As described above the chemical reservoir can contain an active ingredient that dispels insects and in particular mosquitoes and may also, or alternatively, comprise an active ingredient that is an insecticide. It is believed that this embodiment is particularly suited to use in an evening since the container is at least fire resistant should the container and candle be knocked over the flame is unlikely to set light to objects. Additionally the flame is protected from draughts and so will burn steadily.

It has been found that the described chemical vaporisers are particularly effective at dispensing vaporised pyrethrum into the atmosphere. The vaporised pyrethrum is efficacious at dispelling and killing mosquitoes. Accordingly the vaporiser may be used with a reservoir containing pyrethrum as a means of discouraging the presence of mosquitoes and so reducing the number of occurrences of mosquito bites. This is of particular interest in countries in which malaria is a problem. The vaporiser is readily used with candles of a number of different sizes and may ensure that mosquitoes are dispelled through the night hours. The size of candle may be selected depending on the size of the room and the length of time for which it is desired that the candle burns. Thus the vaporiser provided a cheap and effective means of discouraging mosquitoes that can be readily used in locations in which electricity is not readily available.

In addition to use with a chemical such as pyrethrum the vaporiser may also be used with fragrant oils that provide a pleasing ambience when vaporised.

Claims

1. A chemical vaporiser for use with a candle, the chemical vaporiser comprising: a base having an aperture; a cradle adapted to support a reservoir of chemical to be vaporised in use; a spacing portion extending in a first direction from the base and connecting the cradle to the base; and wherein the base has a candle engaging means extending in a second direction generally opposite to the first direction.

2. A chemical vapouriser according to claim 1 in which the candle engaging means comprises at least one spike and preferably two spikes located on opposing sides of the base.

3. A chemical vapouriser according to claim 1 or claim 2 in which the base has an outer diameter from 20mm to 150mm.

4. A chemical vapouriser according to any one of claims 1 to 3 in which the base has a width of from 2mm to 25mm.

5. A chemical vapouriser according to any preceding claim in which the spacing portion comprises two arms arranged on opposing locations on the base and connected to corresponding opposing locations on the cradle.

6. A chemical vapouriser according to any one of claim 1 to 4 in which the spacing portion comprises a shielding envelope.

7. A chemical vapouriser according to any preceding claim wherein the cradle comprises a laminar plate preferably provided with a central aperture.

8. In combination a chemical vaporiser according to any one of claim 1 to 7 and a reservoir of a chemical to be vaporised.

9. A combination according to claim 8 in which the reservoir of chemical to be vapourised comprises a ceramic disc containing a volatile chemical and preferably the volatile chemical comprises pyrethrum.

10. A combination according to claim 9 in which the laminar plate is formed to positively locate the reservoir.

11. A kit suitable for dispersing insects comprising a candle having a top and an outer periphery of the top; a chemical vaporiser having: a base with an aperture, the base being arranged and adapted to be supported on the top of the candle in use and entirely within the outer periphery of the top; a cradle adapted to support a reservoir of chemical to be vaporised in use; a spacing portion extending in a first direction from the base and connecting the cradle to the base; and a reservoir of chemical to be vaporised.

12. A kit according to claim 11 in which the chemical to be vapourised comprises at least one of pyrethrum and piperonyl butoxide as an active ingredient.

13. A kit according to claim 11 or 12 wherein the chemical to be vapourised comprises a buffer solution to control an evaporation rate of an active ingredient.

14. A kit according to any one of claims 11 to 13 in which the candle is provided in a cylindrical container and the chemical vapouriser is sized to fit within the cylindrical container.

15. A method of dispersing insects comprising placing a chemical vaporiser according to any one of claims 1 to 7 onto a candle, locating a reservoir of chemical to be vaporised on the chemical vaporiser and lighting the candle.

16. A method of dispersing insects according to claim 15 wherein the chemical vapouriser moves with an upper surface of the candle as the candle burns such that the cradle is maintained at a substantially constant distance from the flame.

17. A method of dispersing insects according to claim 16 wherein the chemical to be vapourised comprises at least one of pyrethrum and piper onyl butoxide.

18. A method of vaporising a fragrant chemical comprising placing a chemical vaporiser according to any one of claims 1 to 7 onto a candle, locating a source of the fragrant chemical to be vaporised on the chemical vaporiser and lighting the candle.

19 A method of dispersing insects comprising placing a chemical vaporiser on a candle having a top and an outer periphery of the top, the chemical vapouriser comprising; a base arranged and adapted to be supported on the top of the candle in use and entirely within the outer periphery of the top; a cradle; a spacing portion connected between base and the cradle and arranged to space the cradle from the base, wherein the cradle is arranged to support a reservoir of chemical to be vaporised onto a candle, the method further comprising locating a reservoir of chemical to be vaporised on the chemical vaporiser and lighting the candle.

20. A method according to claim 19 wherein the candle is in a cylindrical container.