Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – With means applying electromagnetic wave energy or...
Reexamination Certificate
2000-12-08
2003-08-12
Mayekar, Kishor (Department: 1753)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
With means applying electromagnetic wave energy or...
C422S186070, C422S024000
Reexamination Certificate
active
06605260
ABSTRACT:
This application is a 35 USC 371 National Stage of PCT/DK99/00214 filed Apr. 16, 1999.
FIELD OF THE INVENTION
The invention relates to an apparatus for sterilizing a member including equipment for surgery or medical examination, such as dental handpieces, endoscopes, or catheters. Furthermore, the invention relates to methods for sterilizing a member.
BACKGROUND OF THE INVENTION
After surgery or medical examination of a patient, the equipment used has to be sterilized so that the equipment does not transport any bacteria or virus from the patient to the next patient. Typically, the equipment is sterilized in an autoclave. The autoclave sterilizes outer surfaces of the equipment by subjecting the equipment to an atmosphere of saturated heated aqueous vapor at 120° C. and at a pressure of 2 atmospheres for 20-30 minutes, or for even longer time periods.
It is a disadvantage of an autoclave that repeated sterilization in the autoclave wears and tears on autoclaved members as most materials used for manufacture of such members show a low resistance to aqueous vapor at high temperatures and pressures. For example, members comprising optical components or components made of rubber or silicon can not be sterilized in an autoclave due to those components having a low resistance to the environment in an autoclave.
It is another disadvantage of sterilization in an autoclave that it often takes several minutes or up to one hour to obtain sterilization. Further, heating members in the autoclave also requires time for cooling the member to room temperature. Typically, surgeons or dentists do not have time to wait for their instruments to be autoclaved, and this means that such instruments are not autoclaved as often as may be desired.
DE 29 04 391 discloses an apparatus for sterilizing, such as dental or medical equipment, by use of a source of ultraviolet light and ozone. Members to be sterilized are positioned on shelves in a box. Ozone circulates within the box by convection generated by a heating arrangement.
DE 34 40 078 discloses an apparatus for sterilizing dental equipment. The equipment is sterilized by ultraviolet light provided in a sterilization housing. The equipment is positioned on a dental tray, the tray being vertically movable, so that the tray with the equipment may be moved vertically up and into the sterilization housing wherein an ultraviolet lamp is positioned.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus that is capable of sterilizing members, such as dental or medical instruments, in a short time, such as shorter than 5 minutes. Thus, users of the members may sterilize members frequently, for example after each individual treatment of a patient.
It is a further object of the present invention to provide a sterilization process that results in a shorter sterilization time than the known processes such as the autoclave sterilization.
It is another object of the present invention to provide an apparatus that is capable of sterilizing members that do not cause wear and tear on members to be sterilized.
These objects are achieved by an apparatus for sterilizing a member which, in a first aspect of the present invention, comprises a housing defining an enclosure therein for receiving and holding the member, and a first source of ultraviolet light for illuminating the member with ultraviolet light and which is positioned in the enclosure.
According to the invention, the sterilization of a member is performed by positioning the member in the enclosure defined by the housing. In the enclosure, the first source of ultraviolet light is positioned for illumination of the member. Wall parts of the enclosure may be shaped to increase the intensity of ultraviolet light illuminating the member to be sterilized. The wall parts may have surfaces that reflect ultraviolet light, whereby the ultraviolet light illuminates the entire surface area of the member.
Micro organisms are killed by ultraviolet light since such light breaks DNA strings in the organism. The killing efficiency of the ultraviolet light depends on its wavelength. It has been found that, preferably, the wavelength of the ultraviolet light ranges from 249 to 259 nm, preferably from 250 to 258 nm or from 251 to 257 nm, or more preferably from 252 to 256 nm or from 253 to 255 nm, and most preferably approximately 253.7 nm.
In a preferred embodiment of the invention, the apparatus may further comprise an ozone source for generating ozone to be brought into contact with surfaces. For example, ozone may contact internal surfaces of a member that are not illuminated by the ultraviolet light, for sterilization of the contacted surfaces.
The apparatus may further comprise a pump connected to the ozone source for generation of a forced ozone flow within the enclosure, and a holding component positioned in the enclosure and adapted to receive and hold the member. Preferably, the holding component is connected to the pump so that the ozone flow passes over internal surfaces of the member. Thus, internal surfaces of the member that are not illuminated by the ultraviolet light for sterilization of the contacted surfaces are sterilized by ozone. The ozone has a chemical structure that is toxic and kills micro organisms within a short time.
The pump forces a flow of atmospheric air or oxygen into the ozone generating source, and after the air or oxygen has passed the ozone generator, the ozone is blown into the enclosure and into internal conduits of the member. The pump may blow atmospheric air or oxygen into the ozone generator or may draw air with ozone from the ozone generator. However, in a preferred embodiment, the pump blows atmospheric air or oxygen into the ozone generator so that ozone does not enter the pump.
When sterilizing a member in the enclosure, the member may be positioned in the enclosure on shelves, hanging on wires, etc. However, in a preferred embodiment of the present invention, the apparatus further comprises holding component positioned in the enclosure and adapted to receive and hold the member. The holding component may be a plate having apertures for receiving the members to be sterilized. In a preferred embodiment, the apertures may be positioned in a pipe stub that fits the member to be sterilized. The member is positioned over the pipe stub. The ozone flows through the stub and into internal conduits of the member. The connection between the ozone generator and the holding component may be provided by plastic tubes, rubber tubes, or steel tubes or any other type of tubes that are able to transport ozone.
The generation of ozone in the ozone source may be provided either by sparking in atmospheric air or by illuminating atmospheric air or oxygen with ultraviolet light. In a preferred embodiment, the apparatus comprises an ozone generator that includes its own source of ultraviolet light for generating ozone. By illumination of oxygen with ultraviolet light, oxygen is transformed into ozone. When passing a flow of atmospheric air or oxygen through the generator, the atmospheric air or oxygen is illuminated with ultraviolet light having a preferred wavelength that is particularly effective in transforming oxygen to ozone. The ozone may then be forced into the enclosure and into the internal parts of the member to be sterilized via the above-mentioned stubs.
For effective transformation of oxygen into ozone, the wavelength of the ultraviolet light preferably ranges from 179 to 189 nm, preferably from 180 to 188 nm, such as from 181 to 187 nm, more preferred from 182 to 186 nm, and even more preferred from 183 to 185 nm. It is presently most preferred that the wavelength is approximately 183.7 nm.
The apparatus may further comprise a heating device for heating the forced flow of ozone, so as to increase the activity of the ozone molecules and thereby provide an improved sterilization of surfaces (such as internal surfaces) of the member to be sterilized. The temperature of the heated flow ranges preferably from 40 to 80° C., more preferred from 50 to 70° C., and
Mayekar Kishor
Wenderoth , Lind & Ponack, L.L.P.
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