JPS6058874B2 - Sterilization method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sterilization method capable of processing large quantities of objects to be processed, such as food containers.

Conventionally, irradiation with a germicidal lamp has been used as one of the simple methods for sterilizing fungi.

Conventional germicidal lamps usually have a power consumption of about several tens of watts, and special types have a power consumption of about 200 watts.

However, when the power is about 200 watts, the length of the germicidal lamp becomes about 2 meters long, and the amount of germicidal radiation per unit arc length does not particularly increase significantly. By the way, there are many types of fungi, and for example, in the case of fungi that absorb light well, such as black mold, only the black mold on the surface is sterilized, and the ones that overlap and are located below the black mold on the surface are sterilized. Very difficult to sterilize.

Therefore, conventional germicidal lamps have drawbacks such as long sterilization times and low sterilization rates for bacteria that absorb light well, such as black mold, making them not a very good sterilization method. There is. Generally, the ultraviolet sterilizing effect of a germicidal lamp is given by the following formula.

N0, = e-0 1 ■ lo, e-αx x = β, No,, L Where, No: Number of bacteria before UV irradiation N: Number of bacteria after UV irradiation Q: Constant specific to bacteria 1 : Intensity of ultraviolet rays in the wavelength range effective for sterilization 10: Intensity of the above ultraviolet rays irradiated to the surface layer of bacteria: Irradiation time α: The above ultraviolet absorption coefficient β of bacteria: Constant L: Depth from the surface of the bacterial layer Well, there it is.

Therefore, from these equations, it can be seen that in order to effectively perform sterilization, the value of 1. should be increased. α, β
is a constant specific to bacteria, so in the end, either increase 1 or
Or make it bigger. With conventional germicidal lamps,
10 Therefore, since J1 was also small, it had to be made larger, but even so, in the case of black mold, etc., only the surface layer could be sterilized, and the sterilization rate was low. Furthermore, when sterilizing objects to be processed such as food containers and wrapping paper, a high sterilization rate is required, but in the unlikely event that a lamp or the like breaks during sterilization, fragments may be generated. should not be allowed to adhere to the workpiece.

Therefore, the purpose of the present invention is to provide a sterilization method that can safely and in large quantities treat objects such as food containers and wrapping paper with a high sterilization rate. The purpose is to sterilize fungi on the surfaces of the objects by emitting light from a flash discharge lamp and irradiating the objects through the quartz wall as they move sequentially and reach a sterilization station. Flash discharge lamps themselves are already widely used in industry, but these flash discharge lamps contain rare gases as light emitting components, and their instantaneous light output is 104 to 1 times that of germicidal lamps.
Since it has 0.7 times the strength, suitable results can be expected for use in the present invention.

According to experiments, at an irradiation distance of 10 cm, 10 per cc
A sample containing three cultivated black molds was placed, and a conventional germicidal lamp with an arc length of 30 cm, a voltage of 30 V, a current of 0.8 A, and a bulb inner diameter of 1.2 cm was designed and irradiated continuously. As a type of flash discharge lamp, arc length 30cm, bulb inner diameter 1.2cm, pulse width 1m●S
ec. ．． (time width at a height of 112 of the peak peak value of the pulse: 11 wrinkle height), when flash light irradiation is performed under the conditions of 200 joules of light emission energy and 5 light emissions per second, the former has 1 The number of bacteria on the back of the fish was 1, and the number of bacteria on the latter was 8 seconds later, and the sterilization rate was 99% for the former and 99.999% for the latter. In terms of the number of remaining bacteria, when using a flash discharge lamp, the number of bacteria remaining is -± compared to when using a germicidal lamp.In other words, when using a flash discharge lamp, the number of bacteria remaining is
It can be seen that a high sterilization rate can be obtained in a short time.

Next, the results of a sterilization experiment in a higher emission energy range will be explained.

The samples and flash discharge lamps used were the same as above, but the number of flash discharge lamps was increased, the irradiation distance was set to 25 cm, and the luminous energy of one shot was varied to 600, 900, and 1350 joules. A quartz wall was then interposed between the sample and the flash discharge lamp. Figure 1 shows the relationship between the sterilization rate of 103 black molds and the number of times they emit light. Here, the broken line A is the characteristic distance at 1350 joules, the broken line B is the characteristic distance at 900 joules, and the broken line C is the characteristic distance at 600 joules. is 135
04 joules once, 900 joules 3 times, 60 joules
At 0 joules, it is only necessary to emit light seven times, and it can be said that instantaneous irradiation with higher energy has higher sterilization efficiency, but in any case, a high sterilization rate can be obtained in a short time.

The same experiment was conducted without the quartz wall, but the results were almost the same, confirming that the quartz wall absorbs almost no ultraviolet light. Next, FIG. 2 is an explanatory view of a method for sterilizing objects to be processed in a deep-bottomed container. The objects to be processed 1 are sequentially conveyed to a sterilization station by a belt conveyor 2 that moves continuously or intermittently.

The irradiation lamp 3 can be moved up and down at the sterilization station when the conveyor 2 is in intermittent motion, and can be moved forward in synchronization with the conveyor 2 in addition to the up and down movement when it is in continuous motion. The irradiation lamp 3 has a quartz wall 4 that can be inserted into the container.
is attached, and a flash discharge lamp 5 consisting of a U-shaped bulb xenon flash lamp emits light inside it. When a detector (not shown) detects that the object 1 to be processed has been transported to the sterilization station by the conveyor 2, the irradiation lamp 3 descends and emits light inside the container to sterilize the object. However, the object to be treated 1 may be raised to receive the flash discharge lamp 5 inside the container. When the object 1 to be treated is a flat wrapping paper or a shallow container, an irradiation lamp 3 is constituted by a straight tube-shaped flash discharge lamp 5 and a flat quartz wall 4, and this is attached to the object 1 to be treated. They are brought close together and emitted light to sterilize them. As described above, the present invention uses a flash discharge lamp with a significantly high instantaneous light output in place of the conventional germicidal lamp, so the sterilization rate is extremely high.
Furthermore, since the irradiation is applied to the object to be processed through the quartz wall, even if the 10,000-lamp is damaged, fragments of the lamp will not be attached to the object to be processed. Suitable for sterilization.

Since quartz walls do not absorb ultraviolet rays like Pyrex glass or ordinary glass, the presence of quartz walls does not cause problems such as loss of output. Furthermore, since the objects to be processed are sequentially conveyed to the sterilization station by a conveyor or the like and are continuously processed at the station, there is an advantage that a large amount of objects to be processed can be efficiently sterilized. Brief Description of the Drawings Fig. 1 is an explanatory diagram of data, and Fig. 2 is an explanatory diagram of a sterilization method.

1...Object to be treated, 3...Irradiation lamp, 4
...Quartz wall, 5...Flash discharge lamp.

Claims (1)

[Claims] 1 A flash discharge lamp containing a rare gas as a luminescent component is made to emit light,
A sterilization method characterized by irradiating the light emitted through a quartz wall to objects to be treated that have moved sequentially and reached a sterilization station to sterilize fungi on the surface of the objects to be treated.