Air purifier

Abstract

An air purifier and methods to sterilize an internal surface of an air purifier. The air purifier includes a removable particulate or gas filter, an air flow generator, a controller for said air flow generator, a first air flow setting with an air filtration air flow speed, and a second air flow setting which correlates with sterilization of an internal surface of the air purifier and/or removable particulate or gas filter. The air flow speed measured at the removable filter at the second air flow setting is from 0.1 to 1.2 cms.sup.1.

Claims

1. An air purifier comprising a removable particulate or gas filter, an air flow generator, a controller for said air flow generator, a first air flow setting with a first air filtration air flow speed, and a second air flow setting which correlates with sterilization of an internal surface of the air purifier and/or removable particulate or gas filter and wherein a second air flow speed measured at the removable filter at the second air flow setting is from 0.1 to 1.2 cms.sup.1 and the second air flow speed prevents micro-organism growth, wherein the processor controls the air flow generator to operate at the second air flow setting when the processor receives input from sensors and determines conditions are conducive to micro-organism growth.

2. The air purifier according to claim 1 wherein the air flow speed measured at the removable filter at the first setting is at least 1.5 cms.sup.1.

3. The air purifier according to claim 1 wherein the air flow speed measured at the removable filter at the second setting is from 1 to 40% the air flow speed generated at the first setting.

4. The air purifier according to claim 1 wherein the air flow speed measured at the removable filter at the second setting is from 1 to 10% the air flow speed generated at the first setting.

5. The air purifier according to claim 1 further comprising a timer for timing a period of time after a previous air filtration ends.

6. The air purifier according to claim 1 comprising a knob or switch for actuating said second air flow setting.

7. A method for sterilizing an internal surface of an air purifier according to claim 1 wherein sterilizing is achieved by generating an air flow correlating with said second air flow setting.

8. The method for sterilizing according to claim 7 wherein the internal surface is a removable filter.

9. A method for preventing microbial growth on an internal surface of a removable gas filter from an air purifier according to claim 1 by activating the air flow generator.

10. The method according to claim 9 wherein said air flow generator is activated after a predetermined period of time since last activation of said air flow generator.

Description

EXAMPLE 1

(1) The following experiment sets out to assess the impact of a low air draft alone on micro-organism viability on a substrate, in this case a particulate filter. No ionisation of the substrate took place.

(2) The micro-organisms used were Staphylococcus aureus and Pseudomonas aeruginosa and the incubation period to generate the biofilm was 5 days.

(3) Results:

(4) TABLE-US-00001 Airflow rate (ms.sup.1) 0.018 0.4 1 Log reduction microbes 0.75 0.52 1.2

(5) A low air draft of 0.018 ms.sup.1 resulted in no reduction of micro-organism growth though this still resulted in some slowing down of growth.

EXAMPLE 2

(6) An air purifier was set up such that a particulate filter was subjected to ionisation as well as a low air draft (1 cms.sup.1). The air draft was for 10 hours and the ionisation for 2 hours with the ionisation step coming first.

(7) Again, the ioniser was set at 5 kV and the test micro-organism (Staphylococcus aureus and Pseudomonas aeruginosa) was allowed to grow for 5 days prior to the test.

(8) The control showed log micro-organism count of 6 while the test score was 2.5.

EXAMPLE 3

(9) An air purifier was set up such that an interior surface of the purifier was subjected to ionisation as well as a low air draft (1 cms.sup.1). The air draft was for 10 hours and the ionisation for 2 hours with the ionisation step coming first.

(10) Again, the ioniser was set at 5 kV and the test micro-organism (Staphylococcus aureus and Pseudomonas aeruginosa) was allowed to grow for 5 days prior to the test.

(11) The control showed 152 colonies of micro-organism while the test score showed 6.