1. A vegetable sterilization apparatus comprising: a sterilization tank configured to sterilize vegetables 5 by immersing the vegetables in ozone water, wherein a space above the ozone water held in the sterilization tank is made airtight.

2. The vegetable sterilization apparatus according to claim 10 1, comprising: a vegetable treatment tank provided to at least one of a preceding stage and a subsequent stage of the sterilization tank; a first air feed unit configured to feed air to the 15 vegetable treatment tank; and a first arithmetic and control unit configured to set an air pressure inside the vegetable treatment tank higher than an air pressure inside the sterilization tank by using the first air feed unit. 20

3. The vegetable sterilization apparatus according to claim 2, comprising: a second air feed unit configured to feed the air to the sterilization tank; and 25 a second arithmetic and control unit configured to establish a positive pressure in the sterilization tank by using the second air feed unit.

4. The vegetable sterilization apparatus according to claim 30 2 or 3, wherein the vegetable treatment tank is connected to the sterilization tank in such a way as to allow the air inside the vegetable treatment tank to be fed to the sterilization tank. 27

5. The vegetable sterilization apparatus according to any one of claims 1 to 3, comprising: an ozone gas generation unit configured to generate ozone 5 gas; and an ozone gas feed unit configured to feed the ozone gas generated by the ozone gas generation unit to the sterilization tank. 10 6. A method for producing sterilized vegetables comprising: a sterilization step of sterilizing vegetables by immersing the vegetables in ozone water in a sterilization tank in which the ozone water is held and a space above the held ozone water is made airtight; 15 an air feed step of setting an air pressure inside a vegetable treatment tank higher than an air pressure inside the sterilization tank, the vegetable treatment tank being provided to at least one of a preceding stage and a subsequent stage of the sterilization tank; and 20 a transport step of transporting the vegetables between the vegetable treatment tank with the air pressure set higher in the air feed step and the sterilization tank.

DESCRIPTION
TITLE OF INVENTION
VEGETABLE STERILIZATION APPARATUS AND METHOD FOR
PRODUCITION OF STERILIZED VEGETABLES
5 TECHNICAL FIELD
[0001]
The present invention relates to a vegetable
sterilization apparatus and a method for producing sterilized
vegetables.
10 BACKGROUND ART
[0002]
There is a growing demand for cut vegetables in a package
which can be eaten plain or cooked after the package is opened.
The cut vegetables are produced by cutting vegetables harvested
15 in farms. Here, in most cases, stains such as dirt and live
bacteria adhere to the harvested vegetables. For this reason,
after the vegetables harvested in fields are cut, the cut
vegetable products are often prepared by washing the cut
vegetables with a neutral detergent or the like, followed by
20 sterilization using a sodium hypochlorite aqueous solution or
the like.
[0003]
As a method of sterilizing live bacteria that adhere to
the vegetables, the method using the sodium hypochlorite
25 aqueous solution has been known from the viewpoint of its ease
of handling and low cost. The vegetables are sterilized by
being immersed in the sodium hypochlorite aqueous solution for
a predetermined period of time. However, when a chlorine-based
disinfectant such as sodium hypochlorite is used, the smell of
30 chlorine may remain on the vegetables or by-products may be
generated and remain thereon. For this reason, there is a
demand for development of a sterilization method alternative
to the sodium hypochlorite aqueous solution. In this regard,
3
a sterilization method using ozone water which is a
non-chlorine-based disinfectant has been under study. Ozone
has a property that it is quickly decomposed into oxygen by a
reaction with other substances or by a self-decomposition
5 reaction and is therefore less likely to remain on the
sterilized vegetables.
[0004]
In relation to this technique, Patent Literature 1
describes a sterilization treatment using ozone water even with
10 low disinfecting power, the method including washing leaf
vegetables in a specific method before the sterilization
treatment. Then, this literature also discloses that the
sterilization treatment significantly reduces the number of
bacteria remaining on julienned leaf vegetables thus produced,
15 and suppresses the growth of bacteria with time.
CITATION LIST
Patent Literature
[0005]
Patent Literature 1: Japanese Patent No. 4381349
20 SUMMARY OF INVENTION
Technical Problem
[0006]
The sterilization of the vegetables using the ozone water
is carried out, for example, by immersing the vegetables in an
25 ozone water sterilization tank that holds the ozone water. In
addition, a wash tank for washing the vegetables may be provided,
if necessary, at least at a preceding stage or a subsequent stage
of the ozone water sterilization tank. Such a wash tank is a
pre-wash tank or a post-wash tank, for example.
30 [0007]
Ozone gas in the ozone water is easily desorbed from the
ozone water. In this regard, a possible option is to install
a venting hood above the ozone water sterilization tank, to
4
establish a negative pressure in an environment above the ozone
water sterilization tank, and to constantly discharge the
desorbed ozone gas. In this way, the ozone gas is prevented
from being discharged to the outside of this system.
5 [0008]
However, while the above-mentioned configuration can
prevent the ozone gas from being leaked to the outside, this
configuration also prompts the ozone gas to be desorbed from
the ozone water since the venting fan encourages the discharge
10 thereof. As a consequence, an amount of the ozone gas used
increases in order to recover a reduction in concentration of
the ozone gas, which leads to a high operating cost.
[0009]
The present invention has been made in view of the
15 aforementioned problems. A problem to be solved by the present
invention is to provide a vegetable sterilization apparatus and
a method for producing sterilized vegetables, which are capable
of suppressing desorption of ozone gas and more reliably
preventing a leakage of the ozone gas to the outside at the same
20 time.
Solution to Problem
[0010]
As a result of earnest studies by the inventors of the
present invention in order to solve the aforementioned problem,
25 the inventors have found out that the problem can be solved by
establishing airtightness of a portion above at least an ozone
water sterilization tank among the ozone water sterilization
tank and other tanks provided as appropriate and annexed
thereto.
30 Advantageous Effects of Invention
[0011]
According to the present invention, it is possible to
provide a vegetable sterilization apparatus and a method for
5
producing sterilized vegetables, which are capable of
suppressing desorption of ozone gas and more reliably
preventing a leakage of the ozone gas to the outside at the same
time.
5 BRIEF DESCRIPTION OF DRAWINGS
[0012]
FIG. 1 is a configuration diagram of a vegetable
sterilization apparatus of a first embodiment.
FIG. 2 shows a sterilization flow to be performed by the
10 vegetable sterilization apparatus of the first embodiment.
FIG. 3 is a configuration diagram of a vegetable
sterilization apparatus of a second embodiment.
FIG. 4 shows a sterilization flow to be performed by the
vegetable sterilization apparatus of the second embodiment.
15 FIG. 5 is a configuration diagram of a vegetable
sterilization apparatus of a third embodiment.
FIG. 6 shows a sterilization flow to be performed by the
vegetable sterilization apparatus of the third embodiment.
FIG. 7 is a configuration diagram of a vegetable
20 sterilization apparatus of a fourth embodiment.
FIG. 8 shows a sterilization flow to be performed by the
vegetable sterilization apparatus of the fourth embodiment.
FIG. 9 is a configuration diagram of a vegetable
sterilization apparatus of a fifth embodiment.
25 FIG. 10 shows a sterilization flow to be performed by the
vegetable sterilization apparatus of the fifth embodiment.
DESCRIPTION OF EMBODIMENTS
[0013]
Hereinafter, embodiments of the present invention will
30 be described with reference to the accompanying drawings.
[0014]
[1. First Embodiment]
FIG. 1 is a configuration diagram of a vegetable
6
sterilization apparatus 100 of a first embodiment. The
vegetable sterilization apparatus 100 is configured to
sterilize vegetables V by using ozone water. Conveyors 50 and
60 are connected to the vegetable sterilization apparatus 100.
5 The vegetables V supplied to the vegetable sterilization
apparatus 100 by the conveyor 50 are sterilized in the vegetable
sterilization apparatus 100, and are then supplied to a
not-illustrated packaging apparatus and the like by the
conveyor 60.
10 [0015]
The vegetable sterilization apparatus 100 includes a
pre-wash tank 2, an ozone water sterilization tank 3, a
post-wash tank 4, and a venting hood 10 disposed above these
tanks. The venting hood 10 is partitioned into three
15 compartments (spaces) 20, 30, and 40 by vertically movable
partition plates 11, 12, 13, and 14. Among these compartments,
the compartment 20 is formed above the pre-wash tank 2, the
compartment 30 is formed above the ozone water sterilization
tank 3, and the compartment 40 is formed above the post-wash
20 tank 4. In this embodiment, it is considered that the
compartment 20 is part of the pre-wash tank 2, the compartment
30 is part of the ozone water sterilization tank 3, and the
compartment 40 is part of the post-wash tank 4.
[0016]
25 Meanwhile, the partition plates 11, 12, 13, and 14 are
usually closed and are to be opened when the vegetables V are
transported between any of the compartments 20, 30, and 40.
Accordingly, the respective compartments 20, 30, and 40 are made
airtight when the partition plates 11, 12, 13, and 14 are closed.
30 [0017]
The vegetable sterilization apparatus 100 is provided
with an arithmetic and control unit 70 which controls the
respective constituent units of the vegetable sterilization
7
apparatus 100. The arithmetic and control unit 70 is connected,
by means of not-illustrated electric signal lines, to a drive
unit (not illustrated) for moving the partition plates 11, 12,
13, and 14 up and down, and to air feed-venting fans 22 and 42.
5 Accordingly, in the vegetable sterilization apparatus 100, the
drive unit (not illustrated) for moving the partition plates
11, 12, 13, and 14 up and down and the air feed-venting fans
22 and 42 are controlled by the arithmetic and control unit 70.
The drive of the air feed-venting fans 22 and 42 are temporarily
10 stopped when any of the partition plates 11, 12, 13, and 14 is
opened. Moreover, although it is not illustrated, the
arithmetic and control unit 70 is also configured to control
transport baskets 2a, 3a, and 4a, the conveyors 50 and 60, and
the like (i.e., to control a sterilization flow).
15 [0018]
Here, the arithmetic and control unit 70 includes a CPU
(central processing unit), a RAM (random access memory), a ROM
(read only memory), an HDD (hard disk drive), an I/F (interface),
and the like though none of which are illustrated, and is
20 embodied by causing the CPU to execute a given control program
stored in the ROM.
[0019]
The pre-wash tank 2 is configured to wash the vegetables
V supplied thereto with cold water, thereby removing stains such
25 as dirt adhering to the vegetables V transported by the conveyor
50. The cold water is held in the pre-wash tank 2 and the
transport basket 2a is disposed in such a way as to be immersed
in the cold water. Accordingly, the vegetables V supplied by
the conveyor 50 are put in (thrown in) the transport basket 2a
30 in the pre-wash tank 2 in the first place. Then, the vegetables
V in the state of being put in the transport basket 2a are washed
with the cold water by means of vibration and the like of the
transport basket 2a.
8
[0020]
The partition plates 11 and 12 are closed while the
vegetables V are washed in the pre-wash tank 2. In other words,
the pre-wash tank 2 is in an airtight environment during the
5 washing of the vegetables V in the pre-wash tank 2. Then, the
partition plate 11 is moved up and opened when the vegetables
V are transported to the transport basket 2a in the pre-wash
tank 2 by the conveyor 50.
[0021]
10 The transportation from the pre-wash tank 2 to the ozone
water sterilization tank 3 is accomplished by turning the
transport basket 2a clockwise in FIG. 1 around an end portion
of the transport basket 2a. Specifically, by turning this way,
the vegetables V put in the transport basket 2a are transported
15 to the transport basket 3a in the ozone water sterilization tank
3 at the subsequent stage. Then, the partition plate 11 is
closed again after the transportation is completed. Meanwhile,
as with the first partition plate 11, the partition plate 12
is opened when the vegetables V are transported from the
20 transport basket 2a in the pre-wash tank 2 to the transport
basket 3a in the ozone water sterilization tank 3, and is closed
again after the transportation.
[0022]
Above the pre-wash tank 2, there is provided an air
25 feed-venting port 21 for performing air feed to the compartment
20 formed thereabove and venting from the compartment 20. The
air feed-venting fan 22 is connected to the air feed-venting
port 21, and an air pressure (a positive pressure or a negative
pressure) in the space 20 that is made airtight is controlled
30 by driving the air feed-venting fan 22. In the first embodiment,
the venting from the compartment 20 is performed by rotating
a drive motor (not illustrated) in the air feed-venting fan 22
forward so as to establish the negative pressure inside the
9
compartment 20. On the other hand, the air feed to the
compartment 20 is performed by rotating the drive motor backward
so as to establish the positive pressure inside the compartment
20.
5 [0023]
Moreover, an ozone decomposition unit 23 for decomposing
ozone gas contained in the air discharged from the compartment
20 is connected to the air feed-venting fan 22. Although the
details will be described later, ozone gas desorbed from ozone
10 water in the ozone water sterilization tank 3, which is likely
to exist in the compartment 30 adjacent to the compartment 20,
may flow into the compartment 20. This is why the ozone
decomposition unit 23 is provided so as to decompose the ozone
gas in the air discharged from the air feed-venting fan 22, and
15 to discharge the resultant gas to the outside.
[0024]
The ozone water sterilization tank 3 is configured to
sterilize the vegetables V, which have been washed in the
pre-wash tank 2, by using the ozone water. Cold ozone water
20 is held in the ozone water sterilization tank 3. The cold ozone
water is prepared by a not-illustrated ozone water generation
unit. Meanwhile, although the details will be described later,
the space above the held ozone water is made airtight. Moreover,
the transport basket 3a for containing the vegetables V is
25 disposed in the ozone water sterilization tank 3 as with the
pre-wash tank 2. Furthermore, as with the above-mentioned
pre-wash tank 2, the vegetables V are transported to the
post-wash tank 4 by moving the partition plate 13 up and turning
the transport basket 3a.
30 [0025]
As with the compartment 20 formed above the pre-wash tank
2, an airtight environment is also established in the
compartment 30 formed above the ozone water sterilization tank
10
3. However, unlike the compartment 20, the compartment 30 is
not provided with an air feed-venting port or the like for
establishing the positive pressure or the negative pressure
inside the compartment 30.
5 [0026]
The post-wash tank 4 is configured to wash off the ozone
water adhering to the vegetables V, which have been sterilized
in the ozone water sterilization tank 3, by using clean cold
water. As with the pre-wash tank 2, cold water is held in the
10 post-wash tank 4. Moreover, the transport basket 4a for
containing the vegetables V is disposed in the post-wash tank
4 as with the pre-wash tank 2 and the ozone water sterilization
tank 3. Furthermore, the vegetables V are transported to the
conveyor 60 by moving the partition plate 14 up and down and
15 turning the transport basket 4a.
[0027]
As with the compartments 20 and 30, an airtight
environment is also established in the compartment 40 formed
above the post-wash tank 4. Moreover, as with the compartment
20 20, an air feed-venting port 41 for establishing the positive
pressure or the negative pressure in the compartment 40 formed
above the post-wash tank 4 is provided above the post-wash tank
4. The air feed-venting fan 42 is connected to the air
feed-venting port 41. The positive pressure or the negative
25 pressure is established inside the space 40, which is made
airtight, by driving the air feed-venting fan 42. Furthermore,
as with the compartment 20, the air feed-venting fan 42 and an
ozone decomposition unit 43 are connected to the air
feed-venting port 41.
30 [0028]
FIG. 2 shows a sterilization flow (a method for producing
sterilized vegetables) to be performed by the vegetable
sterilization apparatus 100 of the first embodiment. In the
11
vegetable sterilization apparatus 100, the vegetables V are
sterilized while controlling the pressure in each of the
compartment 20 and the compartment 40 either at the positive
pressure or the negative pressure. The respective units in the
5 vegetable sterilization apparatus 100 are controlled by the
arithmetic and control unit 70 shown in FIG. 1. Note that for
the convenience of explanation, the flow shown in FIG. 2
illustrates not only the flow to sterilize the vegetables V but
also a flow to transport the vegetables V and a flow to control
10 the respective units in the vegetable sterilization apparatus
100.
[0029]
First, the arithmetic and control unit 70 opens the
partition plate 11 (step S101). Then, the vegetables V are
15 thrown into the pre-wash tank 2 by the conveyor 50 (step S102).
Hence, the pre-wash of the vegetables V by using the cold water
is started in the pre-wash tank 2. Subsequently, the arithmetic
and control unit 70 closes the partition plate 11 (step S103).
Accordingly, the compartment 20 formed above the pre-wash tank
20 2 is made airtight.
[0030]
Then, the air feed-venting fan 22 provided in the
compartment 20 is rotated backward in this state (step S104,
an air feed step). Thus, the air feed-venting fan 22 feeds the
25 air to the compartment 20 and the positive pressure is
established in the compartment 20. At this time, the vegetables
V are pre-washed in the pre-wash tank 2 in tandem with the air
feed to the compartment 20.
[0031]
30 When the pre-wash is completed, the arithmetic and
control unit 70 opens the partition plate 12 (step S105). Here,
as described above in step S104, the positive pressure is
established in the compartment 20, whereby the air pressure in
12
the compartment 20 is set to a higher air pressure than the air
pressure in the compartment 30 where the air pressure is not
particularly controlled. For this reason, when the partition
plate 12 partitioning these compartments is opened, the air flow
5 is directed from the compartment 20 to the compartment 30.
Accordingly, the ozone gas in the compartment 30 is less likely
to flow into the compartment 20.
[0032]
Then, the arithmetic and control unit 70 transports the
10 vegetables V from the pre-wash tank 2 to the ozone water
sterilization tank 3 (step S106, a transport step). Thereafter,
the arithmetic and control unit 70 closes the partition plate
12 (step S107, a sterilization step). Accordingly, both of the
compartments 20 and 30 are made airtight, and the vegetables
15 V are sterilized by using the ozone water.
[0033]
Then, the air feed-venting fan 22 provided in the
compartment 20 is rotated forward (step S108). Thus, the air
feed-venting fan 22 discharges the air from the compartment 20
20 and the negative pressure is established in the compartment 20.
Moreover, the air feed-venting fan 42 provided in the
compartment 40 formed above the post-wash tank 4 is rotated
backward (step S109, an air feed step). Thus, the air
feed-venting fan 42 feeds the air to the compartment 40 and the
25 positive pressure is established in the compartment 40. The
positive pressure is established to the extent that the air
pressure in the compartment 40 becomes higher than the air
pressure in the compartment 30.
[0034]
30 When the ozone water sterilization is completed, the
arithmetic and control unit 70 opens the partition plate 13
(step S110). As with step S105 mentioned above, the air flow
is directed from the compartment 40 to the compartment 30 in
13
this step S110 as well. Accordingly, the ozone gas in the
compartment 30 is less likely to flow into the compartment 40.
[0035]
Then, the arithmetic and control unit 70 transports the
5 vegetables V from the ozone water sterilization tank 3 to the
post-wash tank 4 (step S111, a transport step). Thus, the
post-wash of the vegetables V is stated in the post-wash tank
4 by using the cold water. Thereafter, the arithmetic and
control unit 70 closes the partition plate 13 (step S112).
10 Accordingly, both of the compartments 30 and 40 are made
airtight.
[0036]
Then, the air feed-venting fan 42 provided in the
compartment 40 is rotated forward in this state (step S113).
15 Thus, the air feed-venting fan 42 discharges the air from the
compartment 40 and the negative pressure is established in the
compartment 40.
[0037]
When the post-wash is completed, the arithmetic and
20 control unit 70 opens the partition plate 14 (step S114). Then,
the arithmetic and control unit 70 transports the vegetables
V from the post-wash tank 4 to the outside (step S115). Thus,
the sterilization treatment of the vegetables V is completed.
[0038]
25 As described above, when the partition plate 12 or 13 is
opened, the air pressure in the compartment 20 or 40 is higher
than the air pressure in the compartment 30. Accordingly, when
the partition plate 12 or 13 is opened, the air flow is directed
from the compartment 20 or 40 to the compartment 30. For this
30 reason, the ozone gas in the compartment 30 is less likely to
flow into the compartment 20 or 40, so that the ozone gas is
more likely to stay in the compartment 30. Thus, a partial
pressure of the ozone gas in the compartment 30 is likely to
14
be maintained almost at a constant level, and the partial
pressure of the ozone gas is likely to be maintained almost at
the constant level as well. As a consequence, the desorption
of the ozone gas from the ozone water is suppressed.
5 [0039]
[2. Second Embodiment]
Next, a configuration and a controlling method of a
vegetable sterilization apparatus 200 according to a second
embodiment will be described with reference to FIG. 3 and FIG.
10 4. In the following explanation, different features from the
configuration and the controlling method of the vegetable
sterilization apparatus 100 will be mainly described.
Meanwhile, constituents of the vegetable sterilization
apparatus 200 which are the same as those of the above-described
15 vegetable sterilization apparatus 100 will be denoted by the
same reference signs and detailed description thereof will be
omitted.
[0040]
FIG. 3 is a configuration diagram of the vegetable
20 sterilization apparatus 200 of the second embodiment. An air
feed port 31 and an air feed fan 32 are connected to the vegetable
sterilization apparatus 200 in order to feed the air to the
compartment 30 formed above the ozone water sterilization tank
3 of the vegetable sterilization apparatus 100 mentioned above.
25 The arithmetic and control unit 70 controls the air feed fan
32. The drive of the air feed fan 32 is temporarily stopped
when any of the partition plates 11, 12, 13, and 14 is opened.
[0041]
FIG. 4 shows a sterilization flow to be performed by the
30 vegetable sterilization apparatus 200 of the second embodiment.
In the sterilization flow shown in FIG. 4, the steps which are
the same as those in the above-described sterilization flow
shown in FIG. 2 will be denoted by the same step numbers and
15
detailed description thereof will be omitted.
[0042]
First, the vegetables V are pre-washed and the positive
pressure is established in the compartment 20 (steps S101 to
5 S104) as in the case of the above-described vegetable
sterilization apparatus 100. Subsequently, the arithmetic and
control unit 70 feeds the air to the compartment 30 by driving
the air feed fan 32 (step S201). Thus, the positive pressure
is established in the compartment 30. In this way, the air
10 pressure inside the compartment 30 is elevated and the
desorption of the ozone gas from the ozone water is suppressed.
[0043]
However, the air pressure in the compartment 30 to be
elevated in step S201 is set lower than the air pressure in the
15 compartment 20. Specifically, even when the air is fed to the
compartment 30 in step S201, the air pressure in each of the
compartments 20 and 40 is still higher than the air pressure
in the compartment 30. Accordingly, the air flow when the
partition plate 12 is opened is directed from the compartment
20 20 to the compartment 30 as with step S104 mentioned above.
Since the positive pressure is established in the compartment
30 as described above, the ozone gas is less likely to be desorbed.
Nonetheless, the ozone gas may be desorbed a little. In this
regard, by setting the same air flow as that in step S104
25 mentioned above, the ozone gas inside the compartment 30 is less
likely to flow into the compartment 20, whereby the desorption
of the ozone gas from the ozone water to the compartment 30 is
suppressed more efficiently.
[0044]
30 Thereafter, the vegetables V are sterilized as in the
steps S105 to S115 in the above-described vegetable
sterilization apparatus 100. Here, when the positive pressure
is established in the compartment 40 in step S109, the positive
16
pressure is established in the compartment 40 such that the air
pressure in the compartment 40 becomes higher than the air
pressure in the compartment 30. Thus, the ozone gas inside the
compartment 30 is less likely to flow into the compartment 40,
5 whereby the desorption of the ozone gas from the ozone water
to the compartment 30 is suppressed more efficiently.
[0045]
[3. Third Embodiment]
Next, a configuration and a controlling method of a
10 vegetable sterilization apparatus 300 according to a third
embodiment will be described with reference to FIG. 5 and FIG.
6. In the following explanation, different features from the
configurations and the controlling methods of the vegetable
sterilization apparatuses 100 and 200 will be mainly described.
15 Meanwhile, constituents of the vegetable sterilization
apparatus 300 which are the same as those of the above-described
vegetable sterilization apparatuses 100 and 200 will be denoted
by the same reference signs and detailed description thereof
will be omitted.
20 [0046]
FIG. 5 is a configuration diagram of the vegetable
sterilization apparatus 300 of the third embodiment. In the
vegetable sterilization apparatus 300, the ozone gas is used
instead of the air as the gas to be fed to the compartment 30
25 in the vegetable sterilization apparatus 200 mentioned above.
Accordingly, unlike the vegetable sterilization apparatus 200
mentioned above, the vegetable sterilization apparatus 300 is
provided with an ozone gas generation unit 35 which generates
ozone from the air that contains oxygen. In addition, the
30 vegetable sterilization apparatus 300 is provided with an ozone
gas feed fan 36 in order to feed the ozone gas generated by the
ozone gas generation unit 35 to the compartment 30. The
arithmetic and control unit 70 controls the ozone gas feed fan
17
36.
[0047]
FIG. 6 shows a sterilization flow to be performed by the
vegetable sterilization apparatus 300 of the third embodiment.
5 In the sterilization flow shown in FIG. 6, the steps which are
the same as those in the above-described sterilization flow
shown in FIG. 2 will be denoted by the same step numbers and
detailed description thereof will be omitted.
[0048]
10 First, the arithmetic and control unit 70 feeds the ozone
gas to the compartment 30 formed above the ozone water
sterilization tank 3, by controlling the ozone gas feed fan 36
(step S301). By feeding the ozone gas instead of the air, the
partial pressure of the ozone gas in the compartment 30 is
15 elevated. Thus, the desorption of the ozone gas from the ozone
water is suppressed more effectively.
[0049]
Meanwhile, in this embodiment, the amount of the ozone
gas to be fed to the compartment 30 is set to such an amount
20 with which the air pressure inside the compartment 30 becomes
lower than the air pressure in the compartment 20 where the
positive pressure is established in step S104, and lower than
the air pressure in the compartment 40 where the positive
pressure is established in step S109. In this way, the
25 desorption of the ozone gas is sufficiently suppressed as
described above.
[0050]
Thereafter, the vegetables V are sterilized as with the
sterilization flow (steps S101 to S115) in the above-described
30 vegetable sterilization apparatus 100.
[0051]
In the third embodiment, the ozone gas is fed to the
compartment 30. Accordingly, the vegetables V transported
18
from the pre-wash tank 2 and the vegetables V washed in the
transport basket 3a and transported to the post-wash tank 4 come
into contact with the high-concentration ozone gas in the
compartment 30. For this reason, this embodiment can exert a
5 sterilization effect attributed to the contact with the
high-concentration ozone gas in addition to the sterilization
with the ozone water in the ozone water sterilization tank 3.
[0052]
[4. Fourth Embodiment]
10 Next, a configuration and a controlling method of a
vegetable sterilization apparatus 400 according to a fourth
embodiment will be described with reference to FIG. 7 and FIG.
8. In the following explanation, different features from the
configurations and the controlling methods of the vegetable
15 sterilization apparatuses 100 to 300 will be mainly described.
Meanwhile, constituents of the vegetable sterilization
apparatus 400 which are the same as those of the above-described
vegetable sterilization apparatuses 100 to 300 will be denoted
by the same reference signs and detailed description thereof
20 will be omitted.
[0053]
FIG. 7 is a configuration diagram of the vegetable
sterilization apparatus 400 of the fourth embodiment. In the
vegetable sterilization apparatus 400, the air (which may
25 contain the ozone gas as appropriate) is transferred among the
compartment 20, the compartment 30, and the compartment 40. For
this reason, besides the air feed-venting fans 22 and 42 in the
above-described vegetable sterilization apparatus 100 and the
air feed fan 32, the vegetable sterilization apparatus 400 is
30 provided with dampers 51 and 52 for taking in the outside air.
Moreover, these constituents are connected so as to be capable
of performing the air feed and venting in a different manner
from that by the above-described vegetable sterilization
19
apparatus 100 and the like. The arithmetic and control unit
70 controls these constituents.
[0054]
FIG. 8 shows a sterilization flow to be performed by the
5 vegetable sterilization apparatus 400 of the fourth embodiment.
In the sterilization flow shown in FIG. 8, the steps which are
the same as those in the above-described sterilization flow
shown in FIG. 2 will be denoted by the same step numbers and
detailed description thereof will be omitted.
10 [0055]
First, the arithmetic and control unit 70 opens the damper
51 and drives the air feed fan 32 (step S401). Thus, the outside
air is fed to the compartment 30 and the positive pressure is
established in the compartment 30. Subsequently, steps S101
15 to S107 are executed as in the case of the above-described
vegetable sterilization apparatus 100.
[0056]
After the partition plate 12 is closed and the
compartments 20 and 30 are made airtight in step S107, the
20 arithmetic and control unit 70 closes the damper 51 and rotates
the air feed-venting fan 22 forward (step S402). Thus, the air
is discharged from the compartment 20. In addition, since the
air feed fan 32 is driven at this time, the air discharged from
the compartment 20 is fed to the compartment 30. Here, the ozone
25 gas inside the compartment 30 may flow into the compartment 20
as mentioned previously. For this reason, the ozone gas inside
the compartment 20 may be fed to the compartment 30 by the air
feed-venting fan 22 and the air feed fan 32. Thus, the positive
pressure is established in the compartment 30 and the partial
30 pressure of the ozone gas in the compartment 30 is elevated,
whereby the desorption of the ozone gas from the ozone water
is suppressed more effectively.
[0057]
20
Next, the arithmetic and control unit 70 opens the damper
52 after stopping the air feed-venting fan 22 and the air feed
fan 32, and rotates the air feed-venting fan 42 backward (step
S403). Thus, the outside air is fed to the compartment 40 and
5 the positive pressure is established in the compartment 40. The
positive pressure is established to the extent that the air
pressure in the compartment 40 becomes higher than the air
pressure in the compartment 30. Thereafter, steps S110 to S112
are executed as in the case of the above-described vegetable
10 sterilization apparatus 100.
[0058]
Subsequently, the arithmetic and control unit 70 closes
the damper 52, and drives the air feed fan 32 and rotates the
air feed-venting fan 42 forward (step S404). Thus, the air is
15 discharged from the compartment 40, and the discharged air is
fed to the compartment 30. Here, as with the above-described
compartment 20, the ozone gas may also flow from the compartment
30 into the compartment 40. For this reason, by feeding the
discharged air from the compartment 40 to the compartment 30,
20 the partial pressure of the ozone gas in the compartment 30 is
elevated, whereby the desorption of the ozone gas from the ozone
water is suppressed.
[0059]
Thereafter, steps S114 and S115 are executed as in the
25 case of the above-described vegetable sterilization apparatus
100, and the sterilization of the vegetables V is thus
completed.
[0060]
[5. Fifth Embodiment]
30 Next, a configuration and a controlling method of a
vegetable sterilization apparatus 500 according to a fifth
embodiment will be described with reference to FIG. 9 and FIG.
10. In the following explanation, different features from the
21
configurations and the controlling methods of the vegetable
sterilization apparatuses 100 to 400 will be mainly described.
Meanwhile, constituents of the vegetable sterilization
apparatus 500 which are the same as those of the above-described
5 vegetable sterilization apparatuses 100 to 400 will be denoted
by the same reference signs and detailed description thereof
will be omitted.
[0061]
FIG. 9 is a configuration diagram of the vegetable
10 sterilization apparatus 500 of the fifth embodiment. The
apparatus configuration of the vegetable sterilization
apparatus 500 is basically the same as that of the vegetable
sterilization apparatus 400 described with reference to FIG.
7 and the like. However, the vegetable sterilization apparatus
15 500 is provided with the ozone gas generation unit 35 described
above in conjunction with the vegetable sterilization apparatus
300. Accordingly, the vegetable sterilization apparatus 500
corresponds to the configuration of the above-described
vegetable sterilization apparatus 400, which is provided with
20 the ozone gas generation unit 35 of the above-described
vegetable sterilization apparatus 300.
[0062]
FIG. 10 shows a sterilization flow to be performed by the
vegetable sterilization apparatus 500 of the fifth embodiment.
25 In the sterilization flow shown in FIG. 10, the steps which are
the same as those in the above-described sterilization flow will
be denoted by the same step numbers and detailed description
thereof will be omitted.
[0063]
30 First, as with the aforementioned step S301, the
arithmetic and control unit 70 feeds the ozone gas to the
compartment 30 (step S301). Subsequently, steps S101 to S103
are executed as in the case of the above-described vegetable
22
sterilization apparatus 100.
[0064]
Then, the arithmetic and control unit 70 opens the damper
51 and rotates the air feed-venting fan 22 backward (step S501,
5 an air feed step). Thus, the outside air is fed to the
compartment 20 through the damper 51 and the positive pressure
is established in the compartment 20. The positive pressure
is established to the extent that the air pressure in the
compartment 20 becomes higher than the air pressure in the
10 compartment 30. In this way, when the partition plate 12 is
opened in the step S105 mentioned later, the ozone gas that may
exist in the compartment 30 is kept from flowing into the
compartment 20. Accordingly, the desorption of the ozone gas
from the ozone water is effectively suppressed.
15 [0065]
Thereafter, the above-described steps S105 to S107, S402,
S403, S110 to S112, S404, S114, and S115 are executed in this
order. Hence, the sterilization of the vegetables V is
completed.
20 [0066]
[6. Modified Examples]
The vegetable sterilization apparatus and the method for
producing vegetables of the present invention have been
described by citing five embodiments. However, the vegetable
25 sterilization apparatus and the method for producing vegetables
of the present invention are not limited only to the
above-described embodiments. In this context, any one or more
of the above-described embodiments may be carried out in
combination, and any of the embodiments may also be carried out
30 while applying appropriate modifications thereto.
[0067]
For example, in each of the above-described embodiments,
the pre-wash tank 2, the ozone water sterilization tank 3, and
23
the post-wash tank 4 are integrally provided, and the
compartments 20, 30, and 40 are formed by partitioning the space
inside the single venting hood 10 with the partition plates 12
and 13. However, the vegetable sterilization apparatus of the
5 present invention is not limited to the above-mentioned
configuration. For example, the pre-wash tank 2, the ozone
water sterilization tank 3, and the post-wash tank 4 may be built
separately and connected to one other with pipes that can
transport the vegetables V. This configuration is also capable
10 of more reliably preventing the ozone gas from leaking out and
achieving the effect of the present invention.
[0068]
Note that when the pre-wash tank 2, the ozone water
sterilization tank 3, and the post-wash tank 4 are built
15 separately, the compartment 20 can be considered as the space
inside the pre-wash tank 2, the compartment 30 can be considered
as the space inside the ozone water sterilization tank 3, and
the compartment 40 can be considered as the space inside the
post-wash tank 4, respectively.
20 [0069]
Meanwhile, as explained in the respective embodiments
described above, it is preferable to establish the positive
pressure and the negative pressure in the compartments 20, 30,
and 40, for example. Moreover, among these compartments, it
25 is preferable to set the air pressure in the compartment 30 lower
than the air pressures in the compartments 20 and 40. However,
although the above-mentioned aspects are preferable, the air
pressures in the respective tanks in the vegetable
sterilization apparatus of the present invention may be set
30 arbitrarily as long as a portion above the ozone water
sterilization tank 3 is made airtight.
[0070]
In the meantime, while a qualitative operation is carried
24
out in each of the above-described embodiments, a quantitative
operation depending on the air pressures in the respective tanks
may be carried out by providing air pressure sensors to the
respective tanks and the like, for example.
5 [0071]
Furthermore, the configurations of the tanks of the
vegetable sterilization apparatus are not limited to the
illustrated examples. So far as the ozone water sterilization
tank to perform sterilization by using the ozone water is
10 provided, the configurations of other tanks are arbitrary. In
the meantime, as for the aspect of forming the compartments 20,
30, and 40 by partitioning the inside of the single venting hood
10, the present invention is not limited to the aspect of using
the partition plates 11, 12, 13, and 14. For example, double
15 doors are applicable thereto.
[0072]
Still further, the above-described sterilization flows
may be carried out with any of the steps replaced or deleted
as appropriate.
20 Reference Signs List
[0073]
2 pre-wash tank (vegetable treatment tank)
3 ozone water sterilization tank (sterilization tank)
4 post-wash tank (vegetable treatment tank)
25 10 venting hood (sterilization tank, vegetable treatment
tank)
11 partition plate (vegetable treatment tank)
12 partition plate (sterilization tank, vegetable treatment
tank)
30 13 partition plate (sterilization tank, vegetable treatment
tank)
14 partition plate (vegetable treatment tank)
22 air feed-venting fan (first air feed unit)
25
32 air feed fan (second air feed unit)
35 ozone gas generation unit
36 ozone gas feed fan (ozone gas feed unit)
42 air feed-venting fan (first air feed unit)
5 50 arithmetic and control unit (first arithmetic and control
unit, second arithmetic and control unit)
51 damper
52 damper
100 vegetable sterilization apparatus
10 200 vegetable sterilization apparatus
300 vegetable sterilization apparatus
400 vegetable sterilization apparatus
500 vegetable sterilization apparatus

WE CLAIM:
1. A vegetable sterilization apparatus comprising:
a sterilization tank configured to sterilize vegetables
5 by immersing the vegetables in ozone water, wherein
a space above the ozone water held in the sterilization
tank is made airtight.
2. The vegetable sterilization apparatus according to claim
10 1, comprising:
a vegetable treatment tank provided to at least one of
a preceding stage and a subsequent stage of the sterilization
tank;
a first air feed unit configured to feed air to the
15 vegetable treatment tank; and
a first arithmetic and control unit configured to set an
air pressure inside the vegetable treatment tank higher than
an air pressure inside the sterilization tank by using the first
air feed unit.
20
3. The vegetable sterilization apparatus according to claim
2, comprising:
a second air feed unit configured to feed the air to the
sterilization tank; and
25 a second arithmetic and control unit configured to
establish a positive pressure in the sterilization tank by using
the second air feed unit.
4. The vegetable sterilization apparatus according to claim
30 2 or 3, wherein the vegetable treatment tank is connected to
the sterilization tank in such a way as to allow the air inside
the vegetable treatment tank to be fed to the sterilization
tank.
27
5. The vegetable sterilization apparatus according to any
one of claims 1 to 3, comprising:
an ozone gas generation unit configured to generate ozone
5 gas; and
an ozone gas feed unit configured to feed the ozone gas
generated by the ozone gas generation unit to the sterilization
tank.
10 6. A method for producing sterilized vegetables comprising:
a sterilization step of sterilizing vegetables by
immersing the vegetables in ozone water in a sterilization tank
in which the ozone water is held and a space above the held ozone
water is made airtight;
15 an air feed step of setting an air pressure inside a
vegetable treatment tank higher than an air pressure inside the
sterilization tank, the vegetable treatment tank being provided
to at least one of a preceding stage and a subsequent stage of
the sterilization tank; and
20 a transport step of transporting the vegetables between
the vegetable treatment tank with the air pressure set higher
in the air feed step and the sterilization tank.