WO2010060079A1

WO2010060079A1 - Through-material uv sterilization of surfaces and methods

Info

Publication number: WO2010060079A1
Application number: PCT/US2009/065708
Authority: WO
Inventors: John Mcellen; John Zak
Original assignee: Go-Jo Industries Inc
Current assignee: Go-Jo Industries Inc
Priority date: 2008-11-24
Filing date: 2009-11-24
Publication date: 2010-05-27
Anticipated expiration: 2011-05-24

Abstract

The present invention relates to the introduction of UV sterilizing radiation into an object the surface of which it is desired to sterilize. Relatively low intensity radiation may be provided for a relatively long period of time to kill the microorganisms on that surface. Relatively high intensity radiation may be provided for a short period of time, effectively reducing the microorganisms on the surface as well as the hand of the person touching the surface. The circumstances as to when the intensity is varied is application specific. Since the radiation comes from within the material, the problem presented by surface porosity is greatly mitigated. The combination of source and the composition of the material are selected to limit the UV sterilizing radiation passing through the surface to a level that may be safely viewed by the human eye from a predetermined distance from the surface.

Description

THROUGH-MATERIAL UV STERILIZATION OF SURFACES

AND METHODS

RELATED APPLICATIONS

[0001] This application claims the priority of co-pending provisional Application Serial No. 61/193,404 filed November 24, 2008.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to through-material surface sterilization and methods, using ultraviolet radiation.

[0003] Ultraviolet (UV) radiation has been a known mutagen. Recent studies have shown that specific wavelengths and exposure times of ultraviolet light can kill strains of bacteria in both laboratory cultures and animal tissue. One reference characterizes certain subtypes of the electromagnetic spectrum of ultraviolet light as follows as shown in Table 1.

Table 1

[0004] Different types of microorganisms vary significantly in their resistance to UV irradiation. For example, spores such as anthrax have a "cell wall" (like bacteria) as well as an outer "shell" which must be penetrated by the UV energy. Viruses such as influenza, the common cold, SARS, measles and small pox do not have a cell wall and are about twenty times more susceptible to UV-C radiation than spores. Bacteria with a cell wall such as tuberculosis, even extended drug resistant (XDR) TB, may be ten times more vulnerable to UV-C radiation than anthrax spores. The UV-C "dose" needed to destroy germs is generally expressed as joules (one UV-C watt of energy for one second) per square meter; or the equivalent micro-joules per square centimeter (γj/cm²). Staph may be destroyed at a rate of ninety percent with a dose of 20 joules per square meter, e.g., 90% of staph germs will be destroyed in 20 seconds with only 1 watt of UV-C energy and almost all staph germs will be destroyed in sixty seconds with only 1 watt of UV-C energy.

[0005] Surfaces present a unique problem. While many surfaces may appear smooth to the naked eye, many are quite porous to germs. This porosity is particularly problematical to the irradiation of a surface from a source facing the surface because of shadowing, etc

[0006] Because of safety considerations, sterilization with intense germicidal UV radiation is generally conducted interiorly of closed chambers, and the item having the surface to be sterilized is passed through the chamber. For example, attempts to effect sterilization have included a simple box with a switch which is placed over a mouse and keyboard to be sterilized before the UV source is activated. The Ross U.S. Pat. No. 7,372,044 also describes various configurations of a sanitization box housing. It is also known to provide a substantially light tight box with an inclined motorized drawer and door that opens to allow the withdrawal and use of a device such as a keyboard, and which closes to form an ultraviolet light-tight enclosure during which a rapid sanitizing cycle can be performed on the device. The mechanism and internal germicidal lamp in such systems such as disclosed in the Roberts U.S. Pat. No. 6,458,331 may be activated without touching the device by means of an infrared proximity sensor similar to those used in touchless faucets and towel dispensers commonly seen in public restrooms.

[0007] However, it is impractical to pass many surfaces through such a container. Countless examples can be found in environments such as hospitals and elderly care facilities where the people with compromised immune systems can be found, i.e., the beds, the food trays, the tubing through which patients receive a gas such as oxygen, the handles of doors, the TV controls, and the stands from which IVs are hung cannot be passed through a sanitizing chamber. [0008] With increasing numbers of hospitals, clinics, and dental offices moving to fully computerized patient record systems, the number of computer keyboards in these facilities is steadily increasing. Keyboards contaminated with pathogens have been identified as one of the leading vectors for transmission of infections and viruses from patient to patient in hospitals and clinics. Hand washing policies and regular keyboard cleaning policies have had limited effectiveness in practice. Large medical facilities with hundreds or thousands of computer keyboards have deemed it impractical to manually sanitize them with disinfectant more than once or twice per day, even though they may be used by dozens of contaminated employees in between cleanings. [0009] Typical healthcare keyboards have many users, so cross- contamination from and to patients by users can result in fatal consequences. The colonization rate for computer keyboards with potentially pathogenic microorganisms is greater than that of other user interfaces in a surgical ICU. These objects may form additional reservoirs for the transmission of microorganisms and become vectors for cross-transmission. Recent information indicates that Clostridium difficile (CDIF.) and methicillin-resistant Staphylococcus aureus (MRSA) bacteria are capable of prolonged survival, with growths of the bacteria evident 24 hours after contamination. [0010] Many other examples come readily to mind in environments other than health care, particularly where the surface is handled by many different persons, e.g., the floor selection buttons in elevators, the push buttons of gaming devices, the flat screens used by waitresses in placing orders in restaurants, the push buttons of combination door locks, and the check-in kiosks in airline terminals.

[0011] UV sterilizing radiation can be used safely, but must be limited in intensity where the UV source can be seen with the eye. The intensity of UV radiation drops as a function of the distance from the source and thus one may safely look directly at a UV source if the distance is sufficiently great or the intensity of the source sufficiently small. [0012] The amount of UV sterilizing radiation that is effective for sterilization is the integral of the UV intensity level and the length of time the germs are exposed to such radiation, and thus a relatively low UV intensity may be sufficient where the surface can be exposed for sufficient time. In contrast with current sterilization techniques utilizing conventional topical bacteriacidal or bacteriostatic cleaners as well as hydrogen peroxide vaporization whole room sterilizers which are either ineffective or impractical, continuous low level radiation as contemplated herein will be effective in maintaining the sterility of the surface despite repeated contact with contaminated surfaces.

[0013] The present invention relates to the introduction of UV sterilizing radiation into a material the surface of which it is desired to sterilize - through a process of backlighting or transillumination. It is accordingly an object of the present invention to irradiate the contact surface of an object from within or below the material forming the surface.

[0014] It is a further object to provide relatively low intensity radiation for a relatively long period of time to kill the microorganisms on that surface. Since the radiation may come from within the material, the problem presented by surface porosity is greatly mitigated.

[0015] Another object is to provide relatively high intensity radiation for a short period of time, effectively reducing the microorganisms on the surface as well as the hand of the person or object touching the surface.

[0016] The variation in the intensity of radiation may be controlled differently for different applications of the present invention. [0017] In one or more embodiments, the UV sterilizing radiation may be characterized by a wavelength of from about 100 to about 400 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 122 to about 200 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 100 to about 300 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 122 to about 280 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 185 to about 230 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 230 to about 280 nanometers (nm). In another embodiment, the UV sterilizing radiation may be characterized by a wavelength of from about 280 to about 260 nanometers (nm). [0018] It is important that the combination of source and the composition of the material be selected to limit the UV radiation passing through the surface to a level that may be safely viewed by the human eye from a predetermined distance from the surface, i.e. a distance from which a human is not likely to view the surface, e.g. an inch. Because the radiation is present for an extended period of time, the surface will remain sterile despite repeated handling by the patient and the caregivers.

[0019] Further by way of example, the surface may be sterilized by UV sterilizing radiation introduced into the material in a manner such that the material functions as a light pipe. For example, the rails of a hospital bed, or even the tubing for oxygen where UV sterilizing radiation is transmitted down the solid material. In the case of a solid tube such as a bed rail, the UV-C exits the rail along the length thereof at a controlled intensity. In the case of tubing, the UV sterilizing radiation may exit the solid material internally of and externally of the tubing to sterilize both internal and external surfaces, thus improving the quality of the liquid or gas passed through the tube. High intensity discharge ("HID") and LED sources find particular application in "light pipe" applications, where the amount of radiation permitted to exit the surface is a function of the angles of incidence and the configuration of the surface.

THE DRAWINGS

[0020] Fig. 1 is an elevation of a section of a flat contact surface; [0021] Fig. 2 is an elevation showing an elevator call device. [0022] Fig. 3 is an side elevation in partial section showing the movement of the actuator relative to the source.

[0023] Fig. 4 is a plan view in partial section of a corner of keypad. [0024] Fig 5 is a schematic illustration of the existence of an UV field at an elevation limited by the use of baffles which exposes more of the edge of the individual key to the radiation when the key is depressed. [0025] Fig. 6 is an exploded pictorial view of a quick connect sterilizing cart handle.

THE DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0026] The present invention will be described infra in connection with exemplary uses as an elevator call switch, a keyboard and a cart handle. In its broadest sense, however, the invention effects the reduction of microorganisms on the surface of an object by UV sterilizing radiation transmitted outwardly through the material of the object as contrasted with irradiation of the surface from the front thereof.

[0027] With reference to Fig. 1 , a flat plate 10 of UV transmitting material 12 may be provided with a rear layer 14 of UV absorbing material and may be provided with a front layer 16 of UV scattering material. The size of the plate will vary with the application, e.g. food trays or table tops in a hospital environment. [0028] The radiation transmitting material may be any suitable material such as glass, quartz, plastic, acrylic, polycarbonate or polymers, e..g., Teflon FEP, a copolymer of tetrafluorethylene and hexafluoropropylene available from Dupont Company.

[0029] The radiation absorbing material on the back side of the plate may be used for safety reasons to prevent the forward reflection of UV radiation. The scattering layer provides a more uniform level of radiation across the surface of the material.

[0030] UV sterilizing radiation may be caused to pass through the material from above, beneath and/or from the sides thereof, e.g., a series of spaced apart LEDs located on the peripheral edges thereof and/or in an array beneath the top, to present a near uniform intensity over the entire surface. Shielding in the form of an UV adsorbing or reflecting material may be used on the peripheral edges or other radiation hot spots. Alternatively to such edge lighting, the material may be backlit. [0031] The radiation scattering material may be any material that diffuses the UV sterilizing radiation that passes through the surface of the material. Multilayer material and/or thin film coatings may also be used. Diffusion may be accomplished by etching the surface of the object or the object may be coated with UV transmitting thin films which disperse the radiation at flat angles thereby reducing the intensity of the UV-C energy at direct viewing angles. [0032] The UV sterilizing radiation may be provided by any suitable conventional source 18 such as lasers, fluorescent, LED, electro-luminescent, high intensity devices ("HIDs") or other commercially available lamp types. The source may be AC or DC powered and use conventional sockets and auxiliary equipment such as electronic ballasts. The radiation may be introduced into the plate 10 from the edges thereof, i.e. sides, top and/or bottom, e.g. UVC light emitting diodes ("LED's") may be embedded within the plate 10. As earlier indicated, the material may also be backlit.

Elevator Call Switch.

[0033] With reference to the figures where like numerals have been used for like elements, Fig. 2 is a pictorial representation of a prior art fixture used for calling/signaling an elevator car. The fixture is generally mounted in a vertical wall 20 and contains two adjacent flat plates or actuators 22. The actuator plate may be surface mounted, recessed or protrude from the surface of the fixture. Pressure on the plate with the desired arrow 22 makes an electrical contact which may illuminate an indicator bulb within the fixture (not shown) providing a visual signal that the elevator car has been called. The arrow material is usually translucent to permit clear viewing of the signal.

[0034] Fig. 3 shows the movement of the actuator plate 22 to the left or rear when pressed. The movement of the plate 22 to the rear may be conventionally detected to cause the source 18 to turn on and thus to supply a timed burst of UV energy. Alternatively, the source may remain on and the amount of UV energy entering the actuator 22 controlled by the position of the plate 22, i.e., in the position shown in solid lines, the area of the edge not shielded by the wall 20 is smaller than the area exposed to the source when the actuator 22 is moved to the rear position shown in dashed lines. This permits constant low level UV irridation of the outwardly facing surface of the actuator 22 at a level which, given sufficient time (e.g. 30 minutes) between uses of the actuator, will destroy any microorganisms left thereon. The low level radiation is also sufficient to destroy germs not transmitted by contact, i.e., in liquid droplets resulting from a cough or a sneeze.

[0035] This structure also provides an increased level of UV during the periods when the actuator 22 is depressed which will materially reduce microorganisms being applied to the actuator 22 by the current user and remaining on the finger of the current user. The depressing of the actuator 22 may latch the actuator 22 in the rear position for a predetermined period of time sufficient to destroy a predetermined percentage of germs. Where, e.g., the approximate dimension of an actuator plate 22 is 24" square inches (in²), the UV- C energy required to kill 90% of methycillin resistant staph aureus germs ("MRSA") is 20 joules per square meter ("J/M²"). With one watt of UV-C energy transmitted through quartz material, recessing the plate for less than two seconds will destroy approximately 90% of the germs on the surface and on the finger of the operator while the plate 22 is depressed. In an alternative embodiment, the plate may be latched in the rear position for a brief period of time and the burst of high intensity radiation may be delayed until after the finger is removed from the surface.

[0036] Recessing of the device within the wall may be used to control the angle at which radiation enters and leaves the plate 22. The amount of UV energy and the effectiveness of the scattering layer both contribute to the area forward of the actuator 22 where the radiation level reaches the safety limit, e.g. limiting eye exposure to less than zero point four (0.4) microwatts per square centimeter UV-C at a distance beyond three feet from the actuator. [0037] Generally, the invention provides a self sanitizing activator comprising a housing adapted to be supported proximate to an opening in a surface so that the opening provides access to the interior of said housing ; a substantially flat actuator carried by said housing adjacent the opening, said actuator having a contact surface and conveying light at UV sterilizing wavelengths, being movable by pressural contact from a forward position adjacent the opening to a rear position recessed from the opening, and being biased toward said first position; and a source of UV sterilizing radiation carried interiorally of said housing for introducing a first lower amount of radiation into said actuator when in said forward position and a second higher amount of radiation into said actuator when in said rear position., The intensity of the UV sterilizing radiation passing outwardly through the surface of said actuator is at a first lower level when said actuator is in said first forward position and at a second higher level when said actuator is in said second recessed position. Thereby, any microorganisms on said surface are exposed to microorganism destroying UV radiation. Furthermore, the object making pressural contact is also exposed to UV sterilizing radiation. The pressural contact may be made by a human hand, or other human or animal body part.

Keyboard

[0038] Keyboards are omnipresent in today's computer controlled society. Beyond the hospital setting discussed supra, there are several other environments in which computer keyboards or other such equipment are shared by multiple users, thereby facilitating the transfer of germs from one person to another, e.g., internet cafes and public libraries. Keyboards have myriad other uses such as typewriters, vending machines, security pads, gasoline pumps, touch screens, etc., etc. Therefore, the present invention provides a self sanitizing keyboard comprising a housing having mounting surface and a plurality of keys mounted on said mounting surface for effecting a electronic control function when a contact surface thereof is contacted by an object; and a source of UV sterilizing radiation carried by said housing for introducing UV sterilizing radiation into each of said plurality of keys when the surface thereof is contacted, each of said plurality of keys passing a portion of any UV sterilizing radiation introduced by said source outwardly through said surface to irradiate any microorganism on said surface.

[0039] It is desirable to expose the surface of each key to a low level of radiation sufficient to kill microorganisms over a relatively long period of time, e.g. 90% of staph in one hour. It is also desirable to expose the surface of every key to a higher level of radiation with every keystroke.

[0040] Referring to the embodiment of Fig. 4, the keyboard may have a housing 24 internally absorptive of UV with plural sources 26 disposed therein so as to provide UV sterilizing radiation at a particular elevation. As shown in Fig. 5, the individual keys 28 are biased up and depressed when contacted by a finger. In the up position, the exposure of the UV receiving material is more limited than when the key is depressed. Thus, each key will receive a relatively low amount of radiation through the lateral side thereof when not depressed and a relatively high amount of radiation through the lateral side thereof when depressed.

Cart Handles

[0041] Carts have many applications that require the use thereof by many different people over a period of time. Carts are populated with specific supplies and equipment in medical environments for use in specific circumstances. Carts are used by grocery shoppers in supermarkets and the big box retailers. Typically, such carts have a horizontal handle grabbed by the user, who handles many items intermittently with his use, and who then relinquishes the cart to another user. [0042] The present invention provides an improved cart wherein the handle includes a rigid UV diffusing envelope, e.g. a pipe, and an UV emitting light source carried within. In a wheeled cart having a generally horizontal handle adapted to receive the human hand in moving the cart, the present invention provides an improvement wherein the handle comprises a rigid UV diffusing envelope and an UV sterilizing radiation emitting light source carried internally of said envelope.

[0043] As shown in Fig. 6, one embodiment of a handle may comprise a pipe 30 into which is inserted a fluorescent light 32. The pipe 30 must be sufficiently rigid to control the cart and to protect the light when the cart is in use. It must also diffuse the UV from the light 32 that passes through the walls thereof to radiate microorganisms on the handle surface. Teflon (FEP), either as the handle material or as a coating for another suitable UV transparent material may be used.

[0044] With continued reference to Fig. 6, the ends of the handle 34, 36 may contain the sockets for the light 32 and one end may in addition include a rechargeable battery pack 38 to power the light 32. The ends 34, 36 may also be adapted for a conventional quick-release attachment to a fitting 40 on the cart 42 so that the handles may be periodically removed from the cart to recharge the battery.

[0045] For maximum effectiveness, it is desirable that the radiation be a high level when the cart is not in use so that the handle will be sterile when approached by a user. However, for safety reasons, it is desirable that the UV-C energy be a low level when a user is sufficiently close to risk injury by prolonged contact. Thus, the cart may also be provided with one or more strategically placed motion sensors 44 that detect either the proximity of potential users and/or the movement of the cart to reduce the UV intensity. In addition, the application of pressure on the handle 39 by a user may be used to restrict the amount of radiation applied to the handle. The adapting of conventional electronic control circuits for these purposes is well within the level of skill in the art and such circuits have accordingly been omitted from the drawings.

Tubing

[0046] The present invention further provides the radiation transmitting material may be any suitable material such as glass, quartz, plastic, acrylic, polycarbonate or polymers, e.g., Teflon FEP, a copolymer of tetrafluorethylene and hexafluoropropylene available from Dupont Company. [0047] A method is therefore provided for reducing microorganisms in providing gas to a patient compromising the steps of (a) providing a tube adapted to be connected to a source of gas and to a device for administering the gas to a patient; (b) applying UV-C energy to the interior of the UV-C transmitting walls of the tube at a level sufficient to provide UV-C radiation both internally and externally of the tube sufficient (i) to destroy microorganisms that may have been placed on the external surfaces of the tube by the handling of the tube by hospital personnel and (ii) to destroy microorganisms on the internal surface of the tube that may have been placed there by the flow of contaminated gas. [0048] In any of the above embodiments, and other embodiments similar thereto, the present invention provides a method of reducing the microorganisms on a contact surface comprising the steps of (a) providing a solid object having a contact surface that may contain microorganisms thereon and (b) passing UV sterilizing radiation through a portion of the object to exit through the contact surface with sufficient intensity and duration to reduce the microorganisms thereon. The contact surface may be adapted to be touched by humans or other animals, and there may therefore be a risk of the subsequent transfer of the microorganisms to other humans who may thereafter touch the contact surface. [0049] While the foregoing is a description of preferred embodiments of the invention, many variations and modifications will naturally occur to those of skill in this art from a perusal thereof. The invention is therefore not to be limited to the embodiment disclosed, but defined only by the claims when accorded a full range of equivalents.

Claims

CLAIMS What is claimed is:

1. The method of reducing the microorganisms on a contact surface comprising the steps of:

(a) providing a solid object having a contact surface,

(b) passing UV sterilizing radiation through a portion of the object to exit through the contact surface with sufficient intensity and duration to reduce the microorganisms thereon.

2. The method of Claim 1 , wherein the UV-sterilizing radiation is UV-C radiation.

3. The method of Claim 1 , wherein the UV-sterilizing radiation is far UV radiation.

4. The method of Claim 1 , wherein the UV-sterilizing radiation is characterized by a wavelength of from about 100 to about 400 nm.

5. The method of Claim 1 , wherein the UV-sterilizing radiation is characterized by a wavelength of from about 185 to about 230 nm.

6. The method of Claim 1 , wherein the UV-sterilizing radiation is characterized by a wavelength of from about 230 to about 280 nm.

7. The method of Claim 1 wherein the object is a substantially flat plate having edges and wherein the radiation is introduced into the object through an edge.

8. The method of Claim 1 wherein the contact surface is substantially flat and wherein the radiation is introduced into the object at an acute angle to the surface.

9. The method of Claim 1 wherein the surface is coated with a thin film of UV-C transmitting electro-optical material.

10. The method of Claim 1 wherein the surface has an optical control layer thereon to vary the amount of the radiation passing through the surface.

11. The method of Claim 1 wherein the intensity of UV sterilizing irradiation at a predetermined distance from the surface does not exceed a predetermined threshold.

12. The method of Claim 1 , wherein the contact surface is adapted to be touched by humans.

13. The method of Claim 12, wherein the intensity of the radiation passing through the surface is a function of the contact with the surface by a human.

14. The method of Claim 12 wherein the amount of the radiation passing through the surface is a function of the movement of the surface in response to contact by a human.

15. The method of Claim 1 wherein the object has a layer of radiation absorbing material substantially covering surfaces other than the contact surface.

16. The method of Claim 1 wherein the object is a control mechanism for an elevator.

17. The method of Claim 1 wherein the object is a computer keyboard.

18. The method of Claim 1 wherein the object is a food tray.

19. The method of Claim 1 wherein the object is a control for a vending machine.

20. The method of Claim 1 wherein the object is the handle of a cart.

21. A self sanitizing activator comprising: a housing adapted to be supported proximate to an opening in a surface so that the opening provides access to the interior of said housing ; a substantially flat actuator carried by said housing adjacent the opening, said actuator having a contact surface and conveying light at UV sterilizing wavelengths, being movable by pressural contact from a forward position adjacent the opening to a rear position recessed from the opening, and being biased toward said first position; and a source of UV sterilizing radiation carried interiorally of said housing for introducing a first lower amount of radiation into said actuator when in said forward position and a second higher amount of radiation into said actuator when in said rear position, so that the intensity of the UV sterilizing radiation passing outwardly through the surface of said actuator is at a first lower level when said actuator is in said first forward position and at a second higher level when said actuator is in said second recessed position to thereby expose any microorganisms on said surface and any object in contact with said surface to microorganism destroying UV radiation.

22. The activator of Claim 21 wherein the rear portion of said actuator is UV absorbing.

23. The activator of Claim 21 wherein the forward facing portion of said surface scatters the UV radiation which would otherwise pass directly therethrough.

24. The activator of Claim 21 wherein the UV source is a LED.

25. A self sanitizing keyboard comprising: a housing having mounting surface and a plurality of keys mounted on said mounting surface for effecting a electronic control function when a contact surface thereof is contacted by an object; and a source of UV sterilizing radiation carried by said housing for introducing UV sterilizing radiation into each of said plurality of keys when the surface thereof is contacted, each of said plurality of keys passing a portion of any UV sterilizing radiation introduced by said source outwardly through said surface to irradiate any microorganism on said surface.

26. The keyboard of Claim 25 wherein said source introduces a reduced level of UV energy into said plurality of keys when said surface is not in contact with a human finger to thereby expose any microorganisms on said surface to a lower level of microorganism destroying UV radiation.

27. In a wheeled cart having a generally horizontal handle adapted to receive the human hand in moving the cart, the improvement wherein the handle comprises a rigid UV-C diffusing envelope and an UV-C emitting light source carried internally of said envelope.

28. The cart of Claim 27 wherein said handle is battery powered and manually removable from the cart for charging of the battery.

29. The cart of Claim 27 wherein said source is operable at a variable intensity and including a sensor of movement proximate to the cart for reducing the intensity level.

30. The cart of Claim 27 wherein said source is operable at a variable intensity and including a sensor of movement of the cart for reducing the intensity level.

31. The cart of Claim 27 wherein said source is operable at a variable intensity and means for reducing the intensity level when said handle is grasped.

32. A method of reducing microorganisms in providing gas to a patient compromising the steps of:

(a) providing a tube adapted to be connected to a source of gas and to a device for administering the gas to a patient;

(b) applying UV-C energy to the interior of the UV-C transmitting walls of the tube at a level sufficient to provide UV-C radiation both internally and externally of the tube sufficient (i) to destroy microorganisms that may have been placed on the external surfaces of the tube by the handling of the tube by hospital personnel and (ii) to destroy microorganisms on the internal surface of the tube that may have been placed there by the flow of contaminated gas.