CN1194585A - Method for disinfecting the air - Google Patents

Abstract

This invention discloses a method for disinfecting air and killing airborne bacteria by generating disinfectant compound particles using a heated core. The invention particularly relates to a method for generating compound particles known to kill airborne bacteria when dispersed in the air as small particles, which are indirectly generated by heating a core at or near the top. The diols included in the composition are selected from propylene glycol, dipropylene glycol, triethylene glycol, and mixtures thereof.

Description

Methods of Disinfecting the Air

The present invention relates to a method for disinfecting air and killing airborne bacteria using a heated wick to generate particles of disinfecting compounds. In particular, the invention relates to a method of producing particles of compounds known to kill airborne bacteria when dispersed in the air in the form of small particles produced indirectly by heating the wick at or near the top.

The use of indirect heat has been known for a long time as a method of producing fumigating compounds for insecticide materials. Examples of such compositions and methods are disclosed in U.S. Patent 4,745,705. This patent discloses a method of delivering insecticide using a porous absorbent wick by immersing the wick in a solution of insecticide and heating it indirectly overhead to evaporate the adsorbed solution into the atmosphere. This patent does not disclose that the insecticide is dispersed in the air as particles.

In addition, there are many patents disclosing the use of porous cores as means for delivering insecticides. These patents include: US5095647, US4663315, US5038394 and US5290546. None of these patents disclose that these devices can be used to generate air disinfectant particles.

Certain glycol compounds are also known to provide some air cleaning benefits when sprayed into the air. Effective amounts of these materials have been found to generally be about 5% or more active diol (US EPA Document September 3, 1980).

The present invention relates to a method of disinfecting air comprising: immersing a portion of a porous core in a liquid disinfecting composition and indirectly heating the top of the core to generate into the air particles of said active disinfectant, at least 90% of which are The particles produced have a particle size no greater than 10 microns.

Accompanying drawing is the schematic diagram of the device used in the method of the present invention.

As noted above, it is known that certain air disinfectants or air cleaners must be present in the air in some form in order for them to be active. Applicants believe that the agent must be in particulate form and/or attach itself to particles already in the air, such as dust particles, in order to be active. Thus any such air sanitizing or sanitizing agent which can be formulated in a particular form by the heating core generator can be used in the method of the present invention. However, it is preferred to use certain diol compounds when these materials can rapidly produce particles that form an aerosol suspension in air at temperatures safe for use in small consumer appliances. Preferred glycol materials are propylene glycol, dipropylene glycol, triethylene glycol and mixtures thereof. The most preferred compound of these diol materials is dipropylene glycol.

Since many air cleaning active materials are water soluble, the diluent used in the method of the present invention is most preferably water. Other diluents, solvents and co-solvents may also be used, however we believe that highly volatile hydrocarbon solvents reduce the efficacy of the process of the invention and should in principle be avoided. Additionally, other volatile materials such as fragrances should also be avoided or used in small amounts, usually less than 15% of the total formulation. Formulations used in the methods of the present invention are preferably substantially fragrance-free.

The specific concentration of active material in the concentrate contained in the package suitable for the method of the present invention may vary from as little as 5% to as high as 100% active material. Minor amounts of fragrances or fragrances may also be included in this regard without adversely affecting the air cleaning action of the active ingredients. Conversely, the amount of diluent present varies with the amount of active material from 0% at 100% active material to about 95% at about 5% active material. Preferred diluent materials are solvents for the active material. For glycols, the preferred diluent is water.

Turning now to a schematic illustration of the present invention, the present invention comprises a housing or case 10 which includes an opening 20 in the top surface. Located around the opening 20 is a heating element 30 . This element may be any conventional heating element such as a ring heater, a wire wound heater or one or more PTC (Positive Temperature Coefficient) heaters. The detailed type of heating element is not critical to the invention. It is sufficient that the heating element is capable of heating the top of the core 40 to a temperature in the range of about 50-120°C. The heating element 30 is connected by conductors 70 to a power source, which may be a battery pack or a household socket.

Core 40 may be made from any conventional material for such cores. Suitable materials include porous ceramic cores and the like. Suitable core materials are disclosed in US4663315, the disclosure of which is incorporated by reference. Preferred core materials are ceramic, polyester, compressed wood, sintered polypropylene and polyethylene, and carbon fiber.

The core 40 is placed at the opening of the case 50 . Preferably, the wick 40 is placed at the opening of the tank 50 in a sealed form so that the liquid air cleaning material 60 in the tank 50 cannot be easily discharged. The manner in which the core 40 is sealed at the opening of the tank 50 is conventional and does not form part of the present invention.

Surprisingly, evaporative devices of the type described above produce air cleaner particles in a range in which these known cleaner materials are active. It has been observed that more than 90% of the particles produced by the above devices have a particle size in the range of about 0.16-5 microns. Air cleaner materials are very effective in this particle size range.

The method of the present invention will now be demonstrated by the following examples, which are given for the purpose of illustration only and not by way of limitation.

Example 1

Prepare the following recipes:

Component % by weight

Dipropylene glycol 90

Spices (TBA73299) 10

45 g of the above formulation was placed in a bottle with a ceramic core having an average pore size of 0.7 microns. The vial and core combination was then placed in an electric heating unit to heat the top of the core to a temperature of approximately 100°C. The apparatus was placed in a room with temperature and humidity controlled at 22°C and 40% RH. The room was equipped with a Met One # 200 clean room particle counter and a pair of Mattson-Garvin 220 slotted agar impactors to determine the number of bacterial populations over time. About 24 hours later, an airborne bacterium, micrococcus lutens lysodiekticus, was introduced into the room. The total number of particles and the relative size of the particles are determined. The decrease in the number of bacterial populations over this time period was also determined. A control room without any particle-generating devices also had a decrease in the measured bacterial population. The above device produced 6.39 million particles after a period of 24 hours. The weight loss of the formulation in the bottle was 1.67 g over the above time. In the table below, 10-15 refers to 10-15 minutes from introducing bacteria into the room. The bacterial populations were as follows:

        0-5 10-15 20-25 30-35 40-45 50-55

Example 1 1 0 0 0 0 0 0

Comparative example 293 183 146 113 77 44

It is clear that the method reduces the number of airborne bacteria after only a short period of time.

Example 2:

The procedure of Example 1 was repeated, except that the following recipe was used:

Component % by weight

Triethylene glycol 10

Deionized water 90

The number of particles produced over 24 hours was 3.1 million with a weight loss of 0.98 g. The following results were observed.

      0-5 10-15 20-25 30-35 40-45 50-55

Example 2 28 10 5 5 2 4

Comparative example 322 256 161 134 110 77

There was a significant reduction in the number of airborne bacteria that were still present.

The method of the present invention is used to reduce the number of airborne bacteria present in an indoor environment. Since certain bacteria are known to cause disease, the spread of certain infectious diseases can be minimized using the methods of the present invention.

Claims (10)

1. the method for a disinfecting air, comprise and heat the porous core indirectly, this core has a near top and that is arranged in the thermal source and immerses the bottom of liquid disinfection compositions, the top of core has the granule that enough temperature produce described sanitizing composition like this, then with these Dispersion of Particles in air, wherein the particle size that has of at least 90% the granule that produces is no more than 5 microns.

2. the process of claim 1 wherein core is heated to temperature in about 50-120 ℃ of scope.

3. the process of claim 1 wherein that the liquid disinfection compositions comprises that a kind of glycol is as active disinfectant.

4. the method for claim 3, wherein glycol is selected from: propylene glycol, dipropylene glycol, 2,2'-ethylenedioxybis(ethanol). and composition thereof.

5. the method for claim 3, wherein the liquid disinfection compositions comprises that water is as diluent.

6. the method for claim 3, wherein the liquid disinfection compositions contains the water of two pure and mild about 95-0% of about 5-100%.

7. the method for claim 6, wherein glycol is a dipropylene glycol.

8. the method for claim 7, wherein the liquid disinfection compositions contains the dipropylene glycol of about 10-100% and the about water of 0-90%.

9. the method for claim 3, wherein compositions also comprises and is less than 15% spice.

10. the method for claim 3, wherein compositions does not contain spice substantially.