Automatic Residual Toxicity-free Hygienic Unit
Conforming to HACCP Concept

UV-OZONE INDOOR STERILIZING/DEODORIZING

Introduction

Enlightened by the HACCEP system, the recent hygienic management technique in food processing plants or kitchens has achieved an advanced level. Notwithstanding this fact, there seems to be no end to accidents arising from microorganisms, and damages due to such accidents are going on increasing along with the expansion of production scale.
In the field of food processing, if you neglect the hygienic management in the intermediate process, there cannot be any such magic as to solve the issue of microbial contamination or deterioration in quality once for all at the final phase of production.
HACCEP, therefore, requires the assurance of food safety through process analysis, implementation of the priority management focused on vital matters and also the thorough antimicrobial practices in as many processes as possible.
The three leading players of the antimicrobial methods are

Cleanliness (Cleaning)
Low-temperature Management
Sterilizing .

Complying well with the aimed requirements of HACCP, the indoor sterilizing/deodorizing unit utilizing ultraviolet radiation and ozone is automatic and easy to handle.

standard type BIO-CLEAN "BC110W" equipped on a ceiling downward	MINI BIO-CLEAN "OZ51N"for personal use.

Generation of Ozone and Ultraviolet Radiation

The unit takes advantage of ultraviolet radiation and ozone.
Its structure, as shown in Fig. 1, is extremely simple with just the UV lamp and fan accommodated in a stainless steel box.
There are two types of lamp available, one that irradiates the 185nm wavelength line to generate ozone (Ozone Lamp) and the other that irradiates only the line of 254nm wavelength called Sterilizing Radiation (Ozoneless Lamp).
The 254nm wavelength line is used not only for sterilizing but also for activation of ozone.
The 185nm wavelength, on the other hand, can dissolve oxygen but not nitrogen gas.
Based on this principle, the ozone created by UV, unlike those by the silent electric discharge, is clean containing no nitrogen oxides which is harmful to health.
This unit employs ozone as its main player to sterilize and remove a bad odor indoors.

Sterilizing and Deodorizing Mechanism

The UV radiation imparts a strong sterilizing power but only goes straight ahead as it is a sort of light.
So, it is not effective indoors where there are many shields such as machines and equipment, while the gaseous ozone can spread to every corner of room.
A gas of low concentration has a nature to diffuse uniformly into whole space.

Table 1. Effect of Ozone and Its Relation with Concentration

Concentration(ppm)	Effect and Safety
0.02 ---0.05	Criticality with Smell of OzoneCritical sense of smell differs in individuals. As it is lower than the more strict standard safety value of 0.05, ozone is surely safe without any smell. Sense of smell can be an inexpensive monitor for safety.
0.1 or less	Concentration with which 8-hour/day labor is permitted.(Standard values differ among countries. Japan also will revise her standard to 0.05 or less) Deodorizing by the masking effect. Antimicrobial effect in case of a long-term operation for six months. (Concentration: 0.05 up to 0.18ppm)
0.5 ---2.0	Sterilizing/deodorizing effect in a medium term (weeks) operation. Cockroach repellent action. Harmful to human health, not permitted for use when anybody is present.
40	Effects similar to formalin gas fumigation or HIBITANE (Chlorhexidine) spray are attained in a short-term (hours) operation. In-house gas sterilizing of aseptic hospital ward. Unlike formalin, ozone can be exhausted out within one hour after use

Just imagine cigarette smoke, which first goes up to the ceiling with a thread of smoke but next moment it spreads over slowly in the room.
As time goes by, it glazes all over the room. Ozone also behaves like that when its concentration is in the ppm order.
Ozone has a strong oxidizing and sterilizing power, which is promoted in joint use with UV. There is an appropriate concentration and applicable time with which ozone can work giving a proper effect.
Table 1 shows the concentration of ozone and the relation with its effects.
The thicker the concentration, the more effects can be obtained.
However, ozone is harmful to human health like heat and sterilizers like chlorine.
For details see other data. According to the labor hygienic guideline, the ozone concentration under the circumstance of 8-hour labor is regulated to be 0.1ppm or less.

General Description of a Equipment

The UV/Ozone unit is available of two types, the large-scaled model for business use and the small one for personal use.
The former is used with an ozone concentration of 0.5ppm or more indoors and the latter of 0.1ppm or less.
The large model, therefore, cannot be used when workers are there.
As you see in Fig. 1, the large model has such a structure that you set the ozone lamp and ozonefree lamp to the unit body, turn them on at night when nobody is present and then spurt out ozone in the room.
The outlet concentration of ozone is in the order of 50 to 60ppm depending on the models.

In the daytime when workers are present, the unit, switched from the ozonefree lamp, suctions and sterilize air in the unit.
You can control switching of the lamp with timer and set operation time freely.
As for the small model, only the ozone lamp is set.
As a 24-hour continuous operation is standardized, the outlet ozone concentration is set low at 0.2 to 1ppm, so that the indoor concentration may not exceed 0.1ppm.
As the life of UV lamp becomes shorter as the surrounding temperature goes down, it is not good to use the lamp below the room temperature of 10 degree or less.
It is also suggested that you should not blink the lamp frequently because blinking once shortens its life about eight hours.

Ozone Concentration, Contact Time and Measurement

The effects of ozone are influenced by humidity and temperature.
The higher they are, the more effects you obtain.
UV also works to activate ozone and enhance its effect. The most important conditions to utilize ozone are the concentration and contact time of ozone.
It is said that water purification requires a 0.4ppm or more concentration of ozone and its contact time of four minutes or more.
In a gaseous phase, however, conditions are far more complicated and extensive (See Table 1).
For the large model for business use, the indoor concentration of ozone is targeted at 0.5 to 2ppm in consideration of easy and effective use.
The contact time to bring effects with this concentration is counted on a weekly basis.
However, once the indoor floating germs are reduced, the indoor space is kept clean all the way after then.
Disinfection by the ozone which has a high concentration of 60 to 80mg/m3 is so effective equivalent to the formalin gas fumigation or HIBITANE(Chlorhexidine) spray that ozone is used for disinfection of germ-free hospital rooms.
Shown in Table 2 is the comparison result of disinfection power between ozone gas and formalin gas.
Although details are unknown to us about how the filter under mat-pad is composed, ozone gas proves to be inferior to formalin gas in permeability of its disinfection power.
It tells that ozone gas should be used as a surface sterilizing agent.
Ozone concentration indoors is determined by the volumetric capacity of the room, the unit model and the number of installed unit.
The number of installed unit is influenced also by ventilation of the room.
That is why the ozone concentration indoors has to be measured.
Fortunately, in order to measure the targeted concentration of 0.5 to 2ppm and the concentration of 0.1ppm or less for the purpose of safety assurance, there are inexpensive measuring instruments with gas detecting tube available in the market at a price of 20 thousand yen or lower.
The dissolution time of ozone in the air is rather long.
They say that it is about 15 hours when the air is dry or the concentration is reduced to half.
However, the indoor ozone of a concentration ranging from 0.5 to 2ppm is driven out by a ventilation fan in 30 minutes.
Ozone goes back to oxygen by dissolution.

Conclusion

It is said that 90% of deterioration or decay of food is attributed to the secondary infection by germs floating in the air.
The ozone indoor sterilizing/deodorizing unit presents a great effect to control the floating germs.
Furthermore, the unit can be operated automatically, unattended for a long time.
If you add it as a means to support your cleaning management, it will surely bring about immeasurable effects.
A satisfactory management of the ozone concentration is most important for you to succeed in maximizing the effect.