GB2192337A

GB2192337A - Vapourising device

Info

Publication number: GB2192337A
Application number: GB08716374A
Authority: GB
Inventors: Kenneth William James; Roger Harvey Joiner
Original assignee: Beecham Group PLC
Current assignee: Beecham Group PLC
Priority date: 1986-07-12
Filing date: 1987-07-10
Publication date: 1988-01-13
Also published as: GB8716374D0; GB8617015D0

Abstract

A device for vapourising a volatile substance, comprising a housing with an electrical heating element, a recess being formed in the housing to accommodate a metallic foil receptacle containing a composition comprising the volatile substance uniformly dispersed into a gel or free flowing powder. <IMAGE>

Description

SPECIFICATION Device The present invention relates to a heating device, and in particular to an electrically heated device for vapourising volatile substances such as nasal decongestants.

Electrically heated devices of the above general type are known, and an example is disclosed in UK Patent Application No. 2071497. A disadvantage of this known type of device is that the total quantity of volatile substance which can be absorbed by the cellulose pulp carrier elements is limited, particularlywith respectto high dose, volatile, nasal decongestant inhalant materials based on essential oils or their primary active constituents. This in turn means that the period of time during which effective release of vapour can occur is severely restricted.

This problem has now been solved by constructing a device which can accommodate a metal foil pack containing a volatile substance formulated into a gel orfreeflowing powder.

According to the present invention there is provided a device for vapourising a volatile substance, comprising a housing with an electrical heating element, a recess being formed in the housing to accommodate a metallic foil receptacle containing a composition comprising the volatile substance uniformly dispersed into a gel or free flowing powder.

Preferably, the volatile substance is a nasal decongestant material which acts by inhalation such as an essential oil or the main active constituent of an essential oil, although other volatile substances such as insecticides, pesticides, air fresheners and disinfectants may also be used. Examples of decongestant materials are essential oils, such as eucalyptus, peppermint, thyme or pine oil, or their primary active constituents, such as eucalyptol, menthol orthymol.

The volatile substance is preferably combined with a suspending and gelling agent, such as colloidal silica, and paraffin wax to form a wax/gel type of composition. Alternatively, when the volatile substance is an oil, it may be adsorbed onto colloidal silica powder to produce a free-flowing powder composition.

The proportions of volatile substance and colloidal silica in the composition can vary widely.

When colloidal silica is used to formulate the gel, the amount of colloidal silica may be from about 3 to 7% by weight, preferably 4 to 6%. The preferred amount of paraffin wax is from about 20 to 30% by weight, and the preferred range of volatile substance is from about 50 to 70% by weight.

When colloidal silica is used to formulate the free flowing powder, the amount of silica may be from about 20 to 30% by weight and the amount of volatile substance from about 70 to 80% by weight.

The total weight of the composition in the foil receptacle may be from about 1 to 5 g. This enables high levels of volatile material to be included in a receptacle to give effective release of the material over a long period of time.

The metallic foil receptacle preferably consists of an aluminium foil blister which may be covered by a peel-off top layer of aluminium. The composition in the blister is suitably covered with a non-detachable perforated layer of strong material to prevent the composition from becoming accidentally dislodged from the blister during use. The receptacle will normally be disposable, a fresh receptacle being required for each fresh dose of volatile substance.

The device of the invention preferably includes a hinged lid which covers the recess for the receptacle, the lid having slots formed therein to permit the flow of air by convection during heating of the receptacle. The recess is preferably located immediately above the heating element, and is lined with a metallic or ceramic material to aid rapid and uniform distribution of heat around the receptacle.

A device of the invention is now described by way of example with reference to the accompanying drawings, in which, Figure lisa side elevation, pertly in section, of the device, with its hinged lid in the open position.

Figure 2 is a plan view of the device of Figure 1 with the hinged lid removed, and Figure 3 is a plan view of the device of Figure 1 with the hinged lid covering the recess.

Figure 4 is a perspective view of a further embodiment of the device of the present invention.

Referring to Figures 1 to 3 of the drawings, a device 1 for vapourising a volatile substance comprises a body 2 containing a 5 to 15 Watt thermostatically controlled electrical heating element (not shown) located directly beneath a circular recess 3 formed in the top of the body 2.

Attached to the front of the body 2 is a standard UK 3-pin electrical plug unit 4 containing a 3 amp fuse cartridge and a neon light 5 to indicate that electrical power is switched on. The body 2 and plug unit 4 may both be constructed of rigid plastics material, in conventional manner.

Above the recess 3 is located a lid 6, hinged at 7 to the body 2 and formed with parallel slots 9 to permit air convection, and a locking latch 8 which cooperates with a niche 8a formed in the top ofthe body 2. The recess 3, which is lined with ceramic material 10, has an inclined sidewall 11 with equally spaced slots 12 formed therein around its circumference, the purpose of which is to aid air convection.

In use, an aluminium foil blister containing a composition of volatile substance and colloidal silica is placed in the recess 3, and the hinged lid 6 is then closed over the recess 3 to keep the blister securely in place. The plug unit 4 is inserted into a standard electrical socket in a domestic electrical supply (240V -- 13 amp A.C. in the U.K.) causing the heating element to heat the blister to a temperature of from about 60 to 1 500C and the volatile substance to begin vapourising. The slots of 9 and 12 help to create air convection currents, which distribute the vapours around the room where the device is located. The colloidal silica, being inert, remains in the blister and is largely unaffected by the heat.

Because of the possibility of formulating a large dose for the blister, containing a high concentration of volatile material, effective release of the material can be obtained over a long period of time, such as overnight, or throughout the entire day.

The efficient convection of air, carrying the volatile material, may be enhanced by providing additional slots (not shown) in the bottom 13 of the body 2, which communicate with slots 12 at the top.

These additional slots draw in cold air from beneath the device to replace the hot air which is convected upwardly.

Figure 4 shows a second embodiment of the invention. In this embodiment wall 14 is formed with parallel slots 15 to enhance air convection. A neon light 5 is located on wall 14.

Suitable compositions for use in the metallic foil blister are now described in the following Examples: Example 1 A decongestant gel composition was made with the following ingredients: % w/w Eucalyptol 75 Hard Paraffin Wax 20 Colloidal silica 5 100 The hard paraffin wax was first melted, and eucalyptol was gradually added to the molten wax with low shear mixing. Heating was continued until a single phase was obtained. Colloidal silica was then added with high shear mixing until a gel was produced which could be pumped directly into aluminium foil blisters. The amount of composition in each blister was 3.5 g. At room temperature, the composition is in the form of a soft, plastic semisolid, with a sufficiently high shear yield to make it immobile in the foil blister. When heated in the device of the invention, the composition evolves decongestant vapour and, as the oil content decreases, the composition shrinks into a hard wax that remains solid at the working temperature by virtue of the silica content.

A decongestant powder formulation was made with the following ingredients.

% wlw Eucalyptol 75 Colloidal Silica 25 100 Part of the colloidal silica was placed in a powder blender, and a corresponding fraction of eucalyptol was added slowly in stages, separated by a period of blending. This caused a decrease in the bulk volume of the powder, permitting further portions of silica and eucalpytol to be added until ail material had been added. The resulting free-flowing powder was added directly to the blisters, each blister containing about 2.5 g of the composition.

Claims

1. A device for vapourising a volatile substance, comprising a housing with an electrical heating element, a recess being formed in the housing to accommodate a metallic foil receptacle containing a composition comprising the volatile substance uniformly dispersed into a gel orfree4lowing powder.

2. A device according to claim 1, wherein the volatile substance is a nasal decongestant, insecticide, pesticide, air freshener or disinfectant.

3. A device according to claim 1 or 2 wherein the volatile substance is combined with a suspending agent and a gelling agent to form a wax/gel.

4. A device according to claim 3 wherein the suspending agent is colloidal silica and the gelling agent is paraffin wax.

5. A device according to claim 4 wherein the composition comprises from 3 to 7% colloidal silica, 20 to 30% paraffin wax and 50 to 70% volatile substance by weight.

6. A device according to claim 1 or 2, wherein the volatile substance is adsorbed onto colloidal silica powder to produce a free-flowing powder.

7. A device according to claim 6, wherein the composition comprises from 20 to 30% colloidal silica and 70 to 80% volatile substance by weight.

8. A device according to any one of claims 1 to 7, wherein the volatile substance is a nasal decongestant.

9. A device according to any one of claims 1 to 8, comprising a housing with a hinged lid which covers a recess for the foil receptacle, the lid having slots formed therein to prevent the flow of air by convection during heating of the element.

10. A metallic foil receptacle comprising an aluminium foil blister covered by a peel-off top layer of aluminium containing a composition comprising the volatile substance uniformly dispersed into a gel or free-flowing powder and which is protected by a non-detachable perforated layer of material.

11. A metallic foil receptacle according to claim 9, wherein the weight of the composition is in an amount from about 1 to 5 g.

12. A device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.