JP2006149656A - Sterilizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sterilizer capable of reducing the temperature rise of an electrodeless discharge bulb in the case that the radiation of a microwave is continued exceeding a time required for sterilizing an article to be treated. <P>SOLUTION: In the sterilizer having the electrodeless discharge bulb 2 storing a substance emitting an ultraviolet ray by being irradiated with the microwave and sterilizing the surface to be treated by irradiating the surface to be treated of the article to be treated with the ultraviolet ray emitted from the electrodeless discharge bulb 2, a mercury amalgam 2b supplying a rare gas and a mercury vapor is charged inside the electrodeless discharge bulb 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sterilization apparatus for sterilizing an object to be processed with ultraviolet rays using a microwave generator such as a microwave oven in a general household.

As this type of sterilization apparatus, there is one disclosed in Japanese Patent Application Laid-Open No. 2004-147873. FIG. 6 is a perspective view of the sterilization apparatus disclosed therein.
This includes an electrodeless discharge bulb 20 that contains therein a substance that emits ultraviolet rays when irradiated with microwaves, a valve support 3 that supports the electrodeless discharge bulb 20, and an object to be processed 10. A holding unit 4 that holds the workpiece 10 so that the surface faces the ultraviolet emission surface of the electrodeless discharge bulb 20 and a container 9 made of a material that transmits microwaves but does not transmit ultraviolet rays. Yes. The container 9 is divided into two substantially vessel-like bodies 9a and 9b that are openably and closably connected to each other, and each of the inner bottom portions of the substantially vessel-like bodies 9a and 9b has a valve support 3. Is arranged.
Here, the electrodeless discharge bulb 3 is formed by enclosing a rare gas and mercury in a small-diameter glass tube that transmits at least ultraviolet rays, and emits ultraviolet rays having a wavelength suitable for sterilization to the surroundings by microwaves in a microwave oven. is there.

Then, the workpiece 10 is set in one of the substantially container-like bodies 9a, and in this state, the other substantially container-like body 9b is fitted and joined, and the container 11 composed of both of the substantially vessel-like bodies 9a and 9b is closed. When this is accommodated and installed in a microwave oven, the electrodeless discharge bulb 20 emits ultraviolet rays having a wavelength suitable for sterilization to the surroundings by the microwaves irradiated in the microwave oven, and is covered using the microwave oven. The surface to be processed of the processed object 10, that is, the front side surface and the back side surface of the processed object 10 can be sterilized.
JP 2004-147873 A

However, when the electrodeless discharge bulb 20 is irradiated with microwaves, a discharge occurs in the electrodeless discharge bulb 20, thereby generating plasma. The electrons in the plasma are accelerated by the microwave and collide with neutral atoms and the inner wall, thereby increasing the temperature of the electrodeless discharge bulb 20. In particular, if microwave irradiation continues after the time necessary for sterilization of the workpiece 10, the temperature of the electrodeless discharge bulb 20 may rise unexpectedly. Specifically, when the place to be sterilized is operated for about 10 minutes when the microwave oven is operated on the object to be processed 10 for about 10 minutes, the temperature of the electrodeless discharge bulb 20 supports the valve support 3. In some cases, the temperature rises above the heat resistant temperature.
Therefore, in order to prevent a problem even if the microwave oven is operated for a long time, special measures such as forming the valve support 3 with a ceramic material are required.

  The present invention has been made in view of the above-mentioned reasons, and its problem is to reduce the temperature rise of the electrodeless discharge bulb when the microwave irradiation is continued beyond the time necessary for sterilization of the workpiece. It is to provide a sterilizer that can.

Mercury and mercury amalgam have vapor pressure characteristics as shown in FIG. What is characteristic is
-The vapor pressure of mercury amalgam is lower than that of mercury-There are areas where mercury amalgam exists as a solid at temperatures above room temperature, areas where liquid phases are mixed in solids, and areas where liquids exist.
・ Mercury amalgam has different vapor pressure characteristics in each region.
・ Vapor pressure characteristics can be controlled to some extent by changing the ratio of mercury to mercury amalgam.
Etc.
When mercury amalgam is enclosed in an electrodeless discharge bulb as a source of mercury, the vapor pressure of mercury amalgam is higher than that of mercury even when the temperature of the electrodeless discharge bulb rises due to microwaves and discharges inside the electrodeless discharge bulb. Controlled low. For example, assuming that the electrodeless discharge bulb is started and its temperature reaches 40 ° C., mercury is about 0.8 Pascal, while mercury amalgam has only a vapor pressure of 0.133 Pascal and 1/6. . As a result, compared with an electrodeless discharge bulb in which mercury is enclosed, in an electrodeless discharge bulb in which mercury amalgam is enclosed, collision between electrons and mercury in the plasma is reduced, and an increase in bulb temperature due to collision can be suppressed low.

  As described above, the sterilization apparatus according to the first aspect of the present invention has an electrodeless discharge bulb that contains therein a substance that emits ultraviolet rays when irradiated with microwaves. In a sterilizing apparatus for sterilizing a surface to be processed by irradiating the surface to be processed with ultraviolet rays emitted from the object, a mercury amalgam for supplying a rare gas and mercury vapor to the inside of the electrodeless discharge bulb. It is characterized by being enclosed.

  The sterilization apparatus of the invention according to claim 2 is characterized in that the amount of mercury supplied from the mercury amalgam into the electrodeless discharge bulb when the electrodeless discharge bulb is irradiated with microwaves in the electrodeless discharge bulb according to claim 1 Mercury amalgam is enclosed so that it may become 0.133 Pascals-133 Pascals by pressure.

  According to a third aspect of the present invention, there is provided a sterilization apparatus according to the first or second aspect of the present invention, further comprising a start auxiliary valve that generates a discharge when a microwave is irradiated in the vicinity of the electrodeless discharge bulb to emit radiation. A metal film is formed on a part of the inner surface of the auxiliary bulb, and a rare gas of the same type as that enclosed in the electrodeless discharge bulb is enclosed in the starting auxiliary bulb.

  In the first aspect of the invention, the vapor pressure of the mercury amalgam is increased even when the temperature of the electrodeless discharge bulb rises by sealing the rare gas and the mercury amalgam for supplying the mercury vapor inside the electrodeless discharge bulb. Is controlled to be lower than mercury, so that collision between electrons and mercury in the plasma is reduced, and temperature rise of the electrodeless discharge bulb due to collision can be reduced.

  In the invention according to claim 2, when the electrodeless discharge bulb is irradiated with microwaves, the mercury amount supplied from the mercury amalgam into the electrodeless discharge bulb is 0.133 as the electrodeless discharge bulb internal pressure. By enclosing the mercury amalgam so that it becomes Pascal to 133 Pascal, the collision between electrons and mercury in the plasma is reduced more than that of Claim 1, and the temperature rise of the electrodeless discharge bulb due to the collision can be further reduced. It will be a thing.

  In the invention according to claim 3, there is provided a starting auxiliary valve for generating a discharge by emitting a microwave when irradiated with microwaves in the vicinity of the electrodeless discharge bulb, and a part of the inner surface of the auxiliary starting valve. In addition, the starter of the electrodeless discharge bulb can be improved by forming a metal film and enclosing a rare gas of the same type as that enclosed in the electrodeless discharge bulb inside the auxiliary starting bulb.

(First embodiment)
A first embodiment corresponding to claim 1 of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view with a part of the sterilizer cut away, FIG. 2 is a conceptual diagram showing a state in which the sterilizer is accommodated in a microwave generator, and FIG. 3 is a sectional view of an electrodeless discharge bulb.

This sterilization apparatus includes an electrodeless discharge bulb 2 that contains a substance that emits ultraviolet rays when irradiated with microwaves, a valve support 3 that supports the electrodeless discharge bulb 2, and an object to be treated 10. A holding unit 4 that holds the workpiece 10 such that the processing surface faces the ultraviolet emission surface of the electrodeless discharge bulb 2, a container 9 made of a material that transmits microwaves but does not transmit ultraviolet rays, It is configured with.
In addition, the to-be-processed object 10 consists of the nipple tool 10a of the feeding bottle and the fixture 10b which attaches this here.

  The electrodeless discharge bulb 2 has a substantially cylindrical hollow quartz glass tube 2a sealed at both ends in the longitudinal direction, and a mercury amalgam 2b for supplying argon and mercury vapor sealed therein. . The electrodeless discharge bulb 2 is supported by the bulb support 3 so as to irradiate ultraviolet rays emitted from mercury atoms and the like excited by receiving the electric field energy of the microwave toward the inside of the container 9. Here, a bulb support portion 3 is disposed and fixed on each of the inner bottom portions of both substantially container-like bodies 9 a and 9 b that become the container 9, and two electrodeless discharge bulbs 2 supported by the bulb support portions 3. Are opposed to each other in the vertical direction inside the container 9.

  More specifically, the quartz glass tube 2a of the electrodeless discharge bulb 2 has an inner diameter L of 8 mm, a length H of 20 mm, and a thickness of 1 mm, and the mercury amalgam 2b is made of bismuth-indium-mercury. . Here, the mercury content relative to the mercury amalgam 2b is 12% by weight. On the other hand, the comparative example (conventional one) has the same amount of mercury contained in the mercury amalgam 2b enclosed in the electrodeless discharge bulb 20, and the other configuration is as described above. And the same.

  The bulb support portion 3 is made of a fluorine-based thermosetting resin having a heat resistant temperature of 200 ° C. or higher, and is molded simultaneously with the electrodeless discharge bulb 2 while being supported on the bulb support portion 3. The discharge bulb 2 is supported and fixed.

  The holding portion 4 has a plurality of holding pieces 4a arranged around the valve support portion 3, and each holding piece 4a has an opening 4b for engaging and holding the lower end opening edge portion of the baby bottle fitting 10b. Each opening 4b is opened upward, and the lower end opening edge portion of the fixture 10b is inserted into the opening 4b from above to be engaged and held. In addition, the to-be-processed object 10 is not restricted to a baby bottle and its components, What is necessary is just to sterilize and to be accommodated in the container 9 and held by the holding part 4.

  The container 9 has an oval shape, and both substantially container-like bodies 9a and 9b constituting the container 9 are formed of a material that transmits microwaves but does not transmit ultraviolet rays, for example, fluorine resin. In this case, it is preferable that the substantially container-like body 9b, which is located at least on the upper side and serves as a cover, transmits visible light. Further, it is possible to apply a fluorescent material to at least a part of the inner surface or the outer surface of both of the container bodies 9a and 9b, or to mix a fluorescent substance into the material of the both container bodies 9a and 9b. preferable. A plurality of leg pieces 9a1 protrude from the outer periphery of the bottom of the substantially container-like body 9a which is located on the lower side, and the container 9 is placed and held by each leg piece 9a1.

  Next, the usage method of this sterilizer will be described. A nipple device 10a of a baby bottle that has been previously washed with a detergent or the like is mounted on the mounting device 1b, and the inner peripheral thread surface of the mounting device 10b is inserted into the opening 4b of the holding unit 4 so The tool 10a and the fixture 10b) are placed on the holding portion 4 of the lower substantially container 9a. Then, the upper substantially container-like body 9b is fitted and joined to the lower substantially container-like body 9a, and the container 9 composed of the both substantially container-like bodies 9a and 9b is closed. As a result, the lower electrodeless discharge bulb 2 faces the inner surface of the workpiece 10 and the upper electrodeless discharge bulb 2 faces the outer surface of the workpiece 10.

As described above, with the object to be processed 10 accommodated and held in the container 9, as shown in FIG. 2, the container 9 was a microwave oven 15 (700 W output) that was a microwave generator. ) Is housed on the inner bottom surface 15a, the door 15b is closed, the microwave oven 15 is activated, and the microwave is irradiated toward the container 9.
The microwaves pass through the container 9 (both substantially container-like bodies 9a and 9b), and further pass through the workpiece 10 (nipple tool 10a and fixture 10b) to reach the lower electrodeless discharge bulb 2. At the same time, it passes only through the container 9 (both approximately container-like bodies 9a and 9b) and reaches the upper electrodeless discharge bulb 2 as well.

  The microwaves that have reached both electrodeless discharge bulbs 2 excite mercury atoms inside the electrodeless discharge bulb 2, and ultraviolet rays are emitted from the excited mercury atoms. Ultraviolet rays are emitted to the outside through the quartz glass tube 2a of the electrodeless discharge bulb 2, and are irradiated on each of the inner and outer surfaces of the workpiece 10. In this case, the ultraviolet rays emitted from the exposed ultraviolet emission surface of the lower electrodeless discharge bulb 2 are applied to the inner surface of the workpiece 1 and emitted from the exposed ultraviolet emission surface of the upper electrodeless discharge bulb 2. Ultraviolet rays are applied to the outer surface of the workpiece 1.

  The ultraviolet rays are ultraviolet rays having a sterilizing effect of, for example, 254 nm, and sterilize the inner surface and the outer surface of the workpiece 1. The sterilization apparatus according to this embodiment can be easily sterilized with ultraviolet rays by using a microwave oven 15 in a general household, that is, a device that generates a 2.45 GHz (wavelength 12 cm) micro.

  Here, the process in which ultraviolet rays are emitted from the electrodeless discharge bulb 2 will be described in detail. When the electrodeless discharge bulb 2 is irradiated with microwaves, the electrons inside the electrodeless discharge bulb 2 are accelerated and collide with mercury atoms to ionize them. And if the number of electrons increases to some extent, it becomes possible to sustain discharge by receiving direct energy from microwaves. In the state where the discharge is maintained, the electrons are accelerated by the electric field generated by the microwave and collide with the mercury atoms to ionize or excite the mercury atoms. When the excited mercury atom returns to the ground state, the energy difference is emitted as light. One excitation radiation wavelength of mercury is 254 nm ultraviolet light, and this light has a strong bactericidal action. Since electrons collide with neutral atoms and the inner wall of the hollow quartz glass tube 2a in addition to collision with mercury atoms, the temperature of the hollow quartz glass tube 2a rises.

When the temperature of the electrodeless discharge bulb 2 at this time was measured, it was as follows. Specifically, the temperature for 10 minutes, which is 10 times the rated operation time, was measured on the assumption that the sterilizer was used for more than 1 minute, which is the rated operation time.
As a result, the temperature of the electrodeless discharge bulb 2 enclosing the mercury amalgam 2b was about 80 ° C. after 1 minute, which is the rated operation time of the sterilizer, and the temperature after lighting for 10 minutes was about 200 ° C. On the other hand, the electrodeless discharge bulb 20 as a comparative example (conventional) exceeded 120 ° C. in 1 minute after starting, exceeded 200 ° C. after 3 minutes, and reached 245 ° C. after 10 minutes.

  That is, in the electrodeless discharge bulb 2 in which the mercury amalgam 2b is sealed, the temperature when the operation for 1 minute which is the rated operation time is performed can be lowered by 40 degrees. As these results show, when mercury vapor is supplied into the electrodeless discharge bulb 2 using the mercury amalgam 2b, the vapor pressure of mercury is controlled by the mercury amalgam 2b, so that the temperature rise is suppressed and sterilization is highly safe. A device can be obtained.

  According to this embodiment, the vapor pressure of the mercury amalgam 2b is increased even when the temperature of the electrodeless discharge bulb 2 rises by sealing the rare gas and the mercury amalgam 2b supplying mercury vapor inside the electrodeless discharge bulb 2. Is controlled to be lower than mercury, so that collision between electrons and mercury in the plasma is reduced, and temperature rise of the electrodeless discharge bulb due to collision can be reduced. As a result, a fluorine-based thermosetting resin can be used for the bulb support portion 3 that supports the electrodeless discharge bulb 2, and the container 9 that supports the bulb support portion 3 can be made of polypropylene having a lower heat-resistant temperature. Resin can be used.

  In addition, although the mercury amalgam 2b and argon were demonstrated about the enclosure of the electrodeless discharge bulb 2, the same effect can be acquired even if it uses xenon, krypton, neon etc. instead of argon.

  Next, an application example of this embodiment will be described. This application example corresponds to claim 2 of the present invention. FIG. 4 is a graph showing the relationship between the mercury content contained in the mercury amalgam and the temperature of the electrodeless discharge bulb 2. This is one in which the mercury content of the mercury amalgam 2b enclosed in the electrodeless discharge bulb 2 of the sterilizer described above is reduced, and the other components are described in the first embodiment. Is the same. Specifically, the electrodeless discharge bulb with a mercury content of 3.5% by weight is 2X, the electrodeless discharge bulb with a mercury content of 0.8% by weight is 2Y, and the aforementioned implementation The electrodeless discharge bulb having a mercury content of 12% in the weight ratio described in the form of 2 is 2, and the electrodeless discharge bulb corresponding to the above-described comparative example (only mercury but not amalgam) is 20. .

  When the sterilizer configured in this manner is placed in a 1000-watt microwave oven 15 and irradiated with microwaves, the electrodeless discharge valves 2, 20, 2X, and 2Y of the electrodeless discharge valves 2, 20, 2X, and 2Y are the same as those described in the above-described embodiment. The temperature rises. The temperature at this time was as shown in FIG. An example of the electrodeless discharge bulb 2Y will be described. The temperature of the electrodeless discharge bulb 2Y reached 89 ° C. 30 seconds after microwave irradiation, and further 141 ° C. after 60 seconds. In this case, the temperature rise can be reduced more than the electrodeless discharge bulb 2 described in the embodiment.

  Further, when this result was examined, in the electrodeless discharge bulb 20 and the electrodeless discharge bulb 2, the phenomenon that the brightness and the bulb temperature suddenly increased as the temperature of the electrodeless discharge bulb rose (hereinafter this state is referred to as high luminance). Called the discharge mode). This is thought to be due to the fact that the mercury vapor pressure in the electrodeless discharge bulbs 20 and 2 becomes too high due to the chain of temperature rise and mercury vapor pressure increase, resulting in a state close to high pressure discharge.

  Therefore, when the temperature of the electrodeless discharge bulb in this mode was measured, it was about 130 (° C.) for the electrodeless discharge bulb 20 and about 190 (° C.) for the electrodeless discharge bulb 2. Therefore, we made prototype electrodeless discharge bulbs with various mercury contents in the mercury amalgam, measured the temperature of the electrodeless discharge bulb that transitions to the high-intensity discharge mode, and measured the mercury content when the high-intensity discharge mode was started. Vapor pressure was calculated. As a result, it has been found that when the vapor pressure of mercury exceeds 133 Pascal (Pa), the probability that the high-intensity discharge mode appears will increase. Appearance of a high-intensity discharge mode in which the temperature of the electrodeless discharge bulb rises rapidly may cause damage to the handler such as breakage of the sterilizer and burns. Therefore, a highly safe sterilization apparatus can be provided by setting the vapor pressure of mercury to 133 Pascal (Pa) or less.

On the other hand, when the output of the electrodeless discharge bulb 20 is 100%, the amount of ultraviolet rays after 1 minute, which is the rated time, is 160% for the electrodeless discharge bulb 2, 200% for the electrodeless discharge bulb 2X, and electrodeless discharge bulb 2Y. Was able to obtain a UV output of 190%.
Thus, since the temperature of the electrodeless discharge bulb can be reduced and the ultraviolet output can be increased, a safe and highly effective sterilization apparatus can be provided.

  Regarding the lower limit of the vapor pressure of mercury, mercury vapor of 0.133 Pascal or higher, which is a vapor pressure that efficiently emits light having a wavelength suitable for sterilization centered at 254 nm by designing the electrodeless discharge bulb 2. It is desirable to use pressure.

  This is because the amount of mercury supplied from the mercury amalgam into the electrodeless discharge bulb when the electrodeless discharge bulb is irradiated with microwaves is 0.133 Pascals to 133 Pascals in the electrodeless discharge bulb internal pressure, The collision between electrons and mercury in the plasma is reduced, and the temperature rise of the electrodeless discharge bulb due to the collision can be further reduced.

  In particular, in this embodiment, since the temperature of the electrodeless discharge bulb can be suppressed to 150 (° C.) or less, the bulb support portion 3 has durability against ultraviolet rays and has good workability compared to glass. It is possible to use polypropylene (PP) which is inexpensive and has high food safety. By using polypropylene (PP), it is possible to provide a sterilization apparatus that is lightweight and low in cost.

(Second Embodiment)
A second embodiment corresponding to claim 3 of the present invention will be described with reference to FIG. FIG. 5 is a perspective view in which a part of the sterilizing apparatus conceptually illustrated is cut out. This is provided with a starting auxiliary bulb 30 that emits radiation and emits radiation when irradiated with microwaves in the vicinity of the electrodeless discharge bulb 2 of the sterilization apparatus in the first embodiment. Other components are the same as those described in the first embodiment.

  The starting auxiliary bulb 30 has the same shape as the electrodeless discharge bulb 2 and is provided in contact with the electrodeless discharge bulb 2. The start assist valve 30 emits radiation and emits radiation when irradiated with microwaves. A metal film is formed on a part of the inner surface of the start assist valve 30 and the start assist valve 30 The same kind of rare gas as that enclosed in the electrodeless discharge bulb 2 is enclosed.

  More specifically, a clean metal film of barium is formed on the inner surface of the auxiliary start valve 30, and argon is sealed in 1330 pascals (Pa). Since the start assist valve 30 is configured in this way, impurities are reduced in the discharge space due to the getter action of the barium metal film, and in addition, the barium metal film is heated by the microwave, so that barium having a small work function is generated in the discharge space. To emit electrons. For this reason, the initial electrons necessary for starting the discharge are sufficiently supplied, and the starting becomes easy.

  The electrodeless discharge bulb 2 has the same configuration as that described in the first embodiment. Since the electrodeless discharge bulb 2 contains the mercury amalgam 2b, the vapor pressure is lower than that of the mercury-filled mercury described in the comparative example. For this reason, the temperature of the electrodeless discharge bulb 2 before starting (room temperature) is difficult to start because the number of evaporated mercury particles is small. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  When the sterilizer configured in this way is placed inside the microwave oven 15 and irradiated with microwaves, the start assist valve 30 is first started. The starting auxiliary bulb 30 is filled with the same kind of rare gas as the electrodeless discharge bulb 2, here argon, and the electrodeless discharge bulb 2 is irradiated with light emission of argon. Since the argon in the electrodeless discharge bulb 2 can easily obtain the energy required for ionization and excitation from the emission of argon from the starting auxiliary valve 30, dielectric breakdown occurs, and finally the discharge of the electrodeless discharge bulb 2 is discharged. Be started. As a result, the electrodeless discharge bulb 2 can be reliably started, and a highly reliable sterilization apparatus can be provided.

It is a figure which concerns on the 1st Embodiment of this invention, and is the perspective view which notched some sterilizers. It is a conceptual diagram which shows the state which accommodated the same sterilizer in the microwave generator. It is sectional drawing of an electrodeless discharge bulb same as the above. It is a figure which shows the application example of a sterilizer same as the above, and is a figure which shows the relationship between the content rate of the mercury contained in mercury amalgam, and the temperature of an electrodeless discharge bulb. It is the figure which concerns on the 2nd Embodiment of this invention, and is the perspective view which notched a part of the sterilizer conceptually illustrated. It is the perspective view which notched a part of sterilizer based on a prior art example. It is a vapor pressure characteristic figure of mercury and mercury amalgam.

Explanation of symbols

2 Electrodeless discharge bulb 2a Quartz glass tube 2b Mercury amalgam 30 Auxiliary start valve 3 Valve support 4 Holding unit 9 Container 10 Object 15 Microwave oven

Claims (3)

It has an electrodeless discharge bulb that contains a substance that emits ultraviolet rays when irradiated with microwaves, and the surface to be treated is irradiated with ultraviolet rays emitted from the electrodeless discharge bulb. A sterilizing apparatus for sterilizing a processing surface, wherein a rare gas and mercury amalgam for supplying mercury vapor are enclosed in the electrodeless discharge bulb. Mercury amalgam such that when the electrodeless discharge bulb is irradiated with microwaves, the amount of mercury supplied from the mercury amalgam into the electrodeless discharge bulb is 0.133 Pascals to 133 Pascals at the electrodeless discharge bulb internal pressure. The sterilizer according to claim 1, wherein A start auxiliary valve that emits radiation when a microwave is irradiated in the vicinity of the electrodeless discharge bulb is provided, and a metal film is formed on a part of the inner surface of the start auxiliary valve and the start auxiliary valve The sterilizer according to claim 1 or 2, wherein a rare gas of the same type as that enclosed in the electrodeless discharge bulb is enclosed in the inside of the container.

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