GB2334889A

GB2334889A - Killing dust mites in bedding

Info

Publication number: GB2334889A
Application number: GB9905189A
Authority: GB
Inventors: Brian Hill
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-03-05
Filing date: 1999-03-05
Publication date: 1999-09-08
Also published as: GB9905189D0; GB9804704D0

Abstract

An apparatus and method for killing dust mites comprises a cover such as an inflatable bag 6 having an inlet 8 and outlet 10, the bag being adapted to cover a bed or mattress 2 at least partially, and transfer means 14 for introducing a fluid such as air through the bag, the transfer means either heating, cooling, humidifying or dehumidifying the air such that it reaches a temperature and/or humidity outside the range at which dust mites can survive. Preferably the transfer means comprises a fan.

Description

Apparatus and Method for Killing Dust-mites The present invention relates to a method and apparatus for killing dust-mites and has particular, although not exclusive, relevance to the killing of dust-mites in the domestic environment.

The problems which dust-mites pose to humans are well documented. Many years of scientific research have been conducted in relation to dust-mites and the respiratory problems they can cause in humans and the indications are that a single gram of mattress dust may contain up to 5,000 dust-mites. This means that an average mattress or bed could contain anywhere between 10,000 and 2,000,000 dust-mites.

Furthermore the peripheral features of a bed (not only the mattress) such as a pillow a duvet or a blanket could have up to 1% of its own weight being comprised by live or dead dust-mites and their droppings.

Research has shown that a protein which exists in the droppings of dust-mites is the main cause of respiratory problems in humans. The respiratory problems are often associated with an allergic reaction or asthma. These reactions are caused by the protein in the droppings producing an allergen which becomes air-borne and is inhaled by humans. A single dust-mite can produce up to 20 microscopic droppings per day.

When a human being sits or lies down upon a mattress or a pillow etc., this causes a "bellows" effect which creates a cloud of invisible dust thereby allowing the allergen to be inhaled.

Dust-mites tend to live for around 20 to 45 days with the females laying as many as 80 eggs during this period. Dust-mites, however, are not able to drink fluid and therefore must absorb water to survive. They do this by inhabiting humid environments. Further research has shown that dust-mites thrive in environments having a relative humidity ranging from 55% to 85%. Additionally, dust-mites are only able to survive in temperatures of between 15 to 35 "C. This combination of relative humidity and temperature can most readily be found in a domestic environment such as in or around a bed or mattress. When sleeping, humans can sweat up to half a litre of water per night. Much of this water is absorbed into the bedding materials and this provides an ideal environment for dust-mites to thrive.

Various solutions to the problem of removing dust-mites from the human environment have been proposed. One of the most popular and supposedly most effective methods is to apply an aerosol spray to the mattress and bedding. The spray includes a compound which frequently contains the active ingredient S-Bioallethrin and also Bioallethrin. Whilst this is a powerful pesticide, many people are unhappy about the unknown long term effects of application such a pesticide to their sleeping environment. Furthermore many people, particularly asthmatics, are rather unhappy about the inclusion of further chemicals in an environment where they may have to inhale these compounds.

Other less practical solutions are offered to remove dust-mites, such as: steam cleaning of the bedding materials (although this increases the relative humidity): freezing of the bedding materials, which lowering of temperature kills the dust-mites (although it is not clear whether any lavae or eggs are killed or merely go into suspension at such low temperatures): high powered vacuum cleaners (whilst this may well remove a lot of dust-mites and their droppings, they are very tenacious creatures and not all will necessarily be removed). Furthermore, the dust is filtered by the vacuum cleaner, but not necessarily totally effectively, and may be subsequently ejected into the environment of the bedding again: dehumidifiers (these are commonly used to create an environment that is totally alien to dust-mites and can, under certain circumstances, be very effective. Unfortunately, this generally means that there is a need to dehumidify the whole home and this tends to be impractical or expensive).

It is therefore an object of the present invention to provide a method and apparatus for killing dust mites which does not suffer all of the short-comings discussed above. The solution proposed is generally of a more simple and straightforward nature and is cheaper to implement than those systems of the prior art.

Accordingly the present invention provides for apparatus for killing dust-mites comprising: a cover means having a fluid inlet portion and a fluid outlet portion, the cover means adapted to at least partially encapsulate a bed or a mattress containing dust-mites; and fluid transfer means for providing an influx of fluid to the cover means via the inlet portion, the fluid being at a temperature and/or humidity beyond that at which dust-mites can survive, and wherein efflux of the fluid from the cover means occurs via the outlet portion.

Very preferably, the fluid is ambient air. Preferably the fluid is heated to above 35"C, and very preferably to substantially above this temperature, in particular to above about 65"C and preferably to about 80"C to 90"C or higher. It will be appreciated that the temperature alone should be enough to kill dust-mites, but a high temperature is also likely to reduce substantially the ambient humidity.

By using such apparatus it is possible to totally localise the killing of dust-mites to the area of the bed or mattress. It is expected that the region of the bed or mattress near the surface, in particular, will be treated, and the dust-mites tend to inhabit this region.

Preferably the fluid transfer means comprises a fan for forcing fluid into the cover means and resulting in an excess pressure, i.e. above atmospheric pressure, in the cover means. Also the transfer means may be external of the cover means.

Additionally the cover means may comprise an inflatable member and can be formed from sheet material which may be heat resistant. Additionally the cover means may be at least partially elastic and can be formed with an elastic band around the peripheral portion thereof.

Additionally or alternatively, the cover means may be adapted to totally encapsulate a bed or mattress.

According to a further aspect of the present invention there is a provided a method of killing dust-mites present in a bed or mattress comprising: at least partially encapsulating the bed or mattress with a cover means having a fluid inlet portion and a fluid outlet portion; permitting influx of fluid to the cover means, via the inlet portion thereof, and efflux of fluid from the cover means, via the outlet portion thereof, and; maintaining the temperature and/or the humidity of the fluid within the cover means beyond that at which dust-mites can survive, at least for a predetermined period of time. This method also provides for localised killing of dust-mites which is particularly advantageous as compared with the prior art.

Preferably influx of fluid to the cover means is via a fluid transfer means and the fluid transfer means may heat the fluid.

Advantageously the predetermined period of time may be between 1 and 120 minutes and is preferably at least about 50 minutes, and preferably between about 50 minutes and 100 minutes.

The present invention will now be described, by way of example only, and with reference to the accompanying drawings of which: Figure 1 shows a perspective view of an embodiment of the present invention; Figure 2 shows a side view of the embodiment of figure 1; Figure 3 shows a perspective view of an alternative embodiment to that of Figures 1 and 2, and; Figure 4 shows a schematic diagram for the control system associated with the fluid transfer means of the present invention.

Referring now particularly to Figures 1 and 2 it can be seen that a bed 2 which is integrally formed with a mattress at its upper region 4 has been partially encapsulated by a cover means, in this example a fabric cover 6. It can be seen that only the upper region 4 of bed 2 has been totally encapsulated by the fabric cover 6 as this is where the majority of dust-mites within the bed 2 will inhabit.

The fabric cover 6 is formed from a heat resistant material such as HYPALON (Trade Mark) rip-stop nylon, this is necessary due to the elevated temperature which will be used to kill the dust mites, as will be described herebelow. Other materials having appropriate thermal insulating properties may be used as an alternative.

The fabric cover 6 includes a fluid inlet portion, in this example connector piece 8 and a fluid outlet portion, here a 50 micron filter 10. In use of the fabric cover 6, fluid entering the connector piece 8 will increase the pressure within the environment inside the fabric cover 6 and therefore this should be able to inflate. This means that it is advisable for the fabric cover 6 to have a sufficient internal volume to be able to inflate under applied pressure. Those skilled in the art will appreciate that the principles involved here are akin to those used with hot air balloons and the like and so further reference thereto will not be made herein.

As is shown in Figure 1, the fabric cover 6 may have attached to a region thereof a dowel member 12 which can be used for assistance for encapsulation of the bed 2 by the fabric cover 6. The dowel member 12 extends along the entire width of one end of the fabric cover 6 so that the encapsulation operation is eased. Essentially the dowel 12 helps to be able to pull the cover 6 over the bed 2.

It can be seen that the fabric cover 6 includes a plurality of grab members 18 for further assisting in at least partially encapsulating the bed 2.

Also shown in Figure 1 is the fluid transfer means, in this example a fan blower 14 which is employed for providing an influx of fluid into the environment of the fabric cover 6 via the connector piece 8. The fan blower is powered by a conventional mains 240 volt ac power source and blows fluid, in this example air, via a hose member 16 and the connector piece 8.

While those skilled in the art will appreciate that other forms of fluid such as other gases or liquids can be used in the present invention, air is one of the most convenient fluids. Furthermore, although the fluid may be preheated and/or dehumidified before entering the fabric cover 6, it is convenient if the fan blower 14 also includes an electric heating element so that the fluid may be heated thereby. In this way a controlled source of fluid both in terms of the volume flowing into the fabric cover 6 and the temperature and/or humidity thereof may be readily controlled. In this example, therefore, the fan blower 14 also includes an electric heating element (not shown) for heating the air which is urged through the hose member 16.

The fan blower 14 may, as an alternative, or in addition, to including a heating element, may include a cooling element to reduce the temperature of air passing thereby. It may also include a dehumidifying element as is commonly known in the art.

This will serve to cause relative dehumidification of air blown thereby.

The operation of the device described above is as follows. When the fabric cover 6 has been draped over the bed 2 and at least partially encapsulates it, the cover 6, is be inflated by operation of the fan blower 14. As has been discussed above, the fan blower 14 is arranged to provide a source of air under pressure to inflate the fabric cover 6 via the connector piece 8. This influx of air is further arranged to be either dehumidified with respect to the air in the environment and/or to be heated relative thereto. If the air from the fan blower 14 is dehumidified it should be in a range from 0 to 55% or above 85%. If the air is to be heated it should be above 35 "C. As an alternative, it is possible for the air to be cooled as opposed to heated in which case it should be below 15 "C. All of the above ranges are such as to be beyond that survivable by dust-mites. The apparatus is arranged to provide an environment within the cover 6 in which the required temperature and/or humidity parameters are achieved for a predetermined period of time.

Air which has been conditioned in accordance with the above requirements will then circulate around the upper regions 4 of the bed 2 permeating the fabric of the bed thereby killing dust-mites. Preferably there is some way for the air to escape the fabric cover 6 other than via the body of the mattress and this is achieved via the filter 10. Once the fabric cover 6 has been fully inflated then any excess air will generally exit via the filter 10. The filter 10 is arranged to prevent particles escaping which have a size greater than 50 microns and this prevents dust-mites or their droppings from exiting the filter 10.

In the example shown in Figures 1 and 2, the fabric cover 6 does not fully encapsulate the bed 2. This is simply a matter of choice. So long as that region of the bed 2 in which dust-mites exist and are to be killed is encapsulated, then it is believed that the entire bed itself does not necessarily need to be completely encapsulated. This is, however, an option although it is not shown in the attached drawings. Those skilled in the art will appreciate that the present invention will work with equal efficiency if the entire bed 2 is totally encapsulated by the fabric cover 6. The examples shown however include a region 20 of the fabric cover 6 which is elastic. This thereby permits the fabric cover 6 to effectively form an air-tight seal around that region of the bed 2 in which it is in contact. Any known manner of forming the region 20 to the elastic will suffice. For example, a resilient elastic material such as a rubber band or the like may be stitched or inserted into the lower periphery of the fabric cover 6.

By now referring also to Figure 3 it can be seen how an alternative embodiment of that of Figures 1 and 2 includes an alternative form of at least partially encapsulating the bed 2. A lower portion 22 of the fabric cover 6 is arranged to have a hook and loop fastener around its periphery. In this way it may be simply push-fitted against an upper region of a mattress or a duvet, or the like.

Those skilled in the art will appreciate that the overriding requirement for at least partial encapsulation of the bed 2 by the cover member 6, is that the cover member 6 form a sufficiently air-tight seal around the bed 2 to maintain within the cover 6 a body of heated air, etc., from the blower 14. Thus any known method of achieving this purpose will suffice.

Referring now to Figure 4 it can be seen that the fan blower 14 is powered from an AC power source 24. The fan blower 14 includes two sensors, a first temperature sensor 26 and a second pressure sensor 28 which are constituted as probes which are held within fabric cover 6. The probes pass through the hose member 16. In use of the fan blower 14, if an excess of temperature being either too high or too low is detected by temperature sensor 26 and/or an excess of pressure within the inflated fabric cover 6 is detected by pressure sensor 28, then the fan blower 14 may be disabled.

Alternatively it may simply blow air which is then untreated in terms of its temperature or at a lower pressure.

For an effective treatment in accordance with the present invention, it is preferable for the fan blower to be operable for anything up to two to two and a half hours but preferably in the region of one hour. It has been found particularly advantageous for the fan blower to operate between 50 and 100 minutes at both an elevated or reduced temperature and at a relative humidity which is beyond the survival range of dust-mites. In this way, it can be ensured that effective killing of a large percentage of dust-mites within the bed too is achieved.

In a particular preferred embodiment the air is heated to achieve an air temperature within the cover in excess of 60 , and preferably in excess of 80"C, and more preferably it is held in the range from about 80"C to 90 C. At such an elevated temperature it is not necessary to dehumidify the ambient, incoming air.

The present invention has been found to be particularly effective because bedding and household materials such as cotton, wool, kapok and bedding-foam do not deteriorate at the elevated or reduced temperatures or relative humidity described hereabove. In fact they are capable of withstanding far higher limits than have been proposed herein.

It will be understood that the bed 2 may or may not include a mattress as such.

If the bed does include a mattress, this need not be integral with the bed, but may be a separate article.

Those skilled in the art will appreciate that the fluid transfer means, in the ak ove example a fan blower 14, may be formed integrally with the fabric cover 6 or may even be formed within the fabric cover 6. There is no compulsion for the fluid transfer means to be a separate element external of the fabric cover 6.

In the event of the fan blower 14 conditioning the fluid blown thereby only by way of its humidity as opposed to its temperature, then the fabric cover 6 need not be heat-resistant.

Those skilled in the art will appreciate that, by suitable choice of the material from which the fabric cover 6 is made, it can be possible to dispense with the filter 10.

This is because the material of the fabric cover 6 can itself act as a filter if the weave of the material is sufficiently fine.

Claims

CLAIMS: 1. Apparatus for killing dust-mites comprising: a cover means having a fluid inlet portion and a fluid outlet portion, the cover means adapted to at least partially encapsulate a bed or a mattress containing dust-mites and fluid transfer means for providing an influx of fluid to the cover means via the inlet portion, the fluid being at a temperature and/or humidity beyond that at which dust-mites can survive, and wherein efflux of the fluid from the cover means occurs via the outlet portion.
2. Apparatus according to claim 1 wherein the fluid transfer means is external of the cover means.
3. Apparatus according to claim 1 or claim 2 wherein the fluid transfer means heats the fluid.
4. Apparatus according to any one of the preceding claims wherein the fluid transfer means comprises a fan for forcing fluid into the cover means.
5. Apparatus according to any one of the preceding claims wherein the fluid comprises air.
6. Apparatus according to any one of the preceding claims wherein the cover means comprises an inflatable member.
7. Apparatus according to claim 6 wherein the inflatable member is formed from sheet material.
8. Apparatus according to any one of the preceding claims wherein the cover means is at least partially elastic.
9. Apparatus according to claim 9 wherein the cover means includes an elastic band around a peripheral portion thereof.
10. Apparatus according to any one of the preceding claims wherein the cover means is adapted to totally encapsulate a bed or mattress.
11. Apparatus according to any one of the preceding claims wherein a build-up of pressure within the cover means due to the fluid transfer means occurs.
12. Apparatus substantially as hereinbefore described and with reference to the accompanying drawings.
13. A method of killing dust-mites present in a bed or mattress comprising: at least partially encapsulating the bed or mattress with a cover means having a fluid inlet portion and a fluid outlet portion; permitting influx of fluid to the cover means, via the inlet portion thereof, and efflux of fluid from the cover means, via the outlet portion thereof, and; maintaining the temperature and/or the humidity of the fluid within the cover means beyond that at which dust-mites can survive, at least for a predetermined period of time.
14. A method according to claim 13 wherein influx of fluid to the cover means is via a fluid transfer means.
15. A method according to claim 14 wherein the fluid transfer means heats the fluid.
16. A method according to any one of claims 13-15 wherein the predetermined period of time is between 1 and 120 minutes.
17. A method according to claim 16 wherein the predetermined period of time is between 50 and 100 minutes.
18. A method according to claim 13 wherein the temperature is less than 15 "C or greater than 35 "C.
19. A method according to claim 13 wherein the humidity is less than 55% or greater than 85%
20. A method according to any one of claims 13 to 17, wherein the temperature is greater than about 60"C.
21. A method according to claim 20, wherein the temperature is greater than about 80"C.
22. A method as claimed in claim 21, wherein the temperature is from about 80C to about 90"C.
23. A method according to any one of claims 13 to 22, wherein the fluid is air.
24. A method as claimed in claim 23, wherein the incoming air is not treated to remove its water content.
25. A method of killing dust-mites substantially as hereinbefore described and with reference to the accompanying drawings.