Sterilizing device

Abstract

To provide a sterilization device which can prevent sterilization of matter to be treated accommodated in a treatment tank from becoming ununiform.SOLUTION: According to the present invention, a sterilization device which carries out sterilization treatment of matter to be treated comprises: a treatment tank; sterilization water supply means; and ejection means. The treatment tank is configured to accommodate the matter to be treated. The sterilization water supply means is configured to supply sterilization water. The ejection means comprises an upper nozzle and a side nozzle. The upper nozzle is configured to eject the sterilization water from an upper portion of the matter to be treated accommodated in the treatment tank. The side nozzle is configured to eject the sterilization water from a side portion of the matter to be treated accommodated in the treatment tank. The sterilization device further comprises flow rate changing means which can reduce an amount of ejection of the sterilization water from the upper nozzle without reducing an amount of ejection of the sterilization water from the side nozzle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sterilization device used for sterilizing retort foods and the like.

Background Art

[0002] Conventionally, there has been a sterilization device that accommodates an object to be treated in a treatment tank and performs sterilization by ejecting sterilizing water into the treatment tank. For example, Patent Document 1 discloses a heat sterilization device that circulates water in a treatment tank (sterilization tank), heats it with a heat exchanger, and ejects it from a nozzle (jet nozzle) provided in the treatment tank.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, nozzles for ejecting sterilizing water into the treatment tank are preferably installed at the upper part and the side part of the treatment tank in order to effectively sterilize the object to be treated.

[0005] However, when sterilizing water is ejected from a nozzle (upper nozzle) installed at the upper part of the treatment tank, the upper part of the object to be treated is intensively sterilized. Further, when performing sterilization by accommodating a plurality of trays on which the objects to be treated are placed in the treatment tank in multiple stages, the objects to be treated on the uppermost tray are intensively sterilized by the upper nozzle, and there is a risk of adversely affecting the quality of some of the objects to be treated.

[0006] The present invention has been made in view of such circumstances, and provides a sterilization device capable of suppressing non-uniform sterilization of an object to be treated accommodated in a treatment tank.

Means for Solving the Problems

[0007] According to the present invention, there is provided a sterilization apparatus for sterilizing an object to be treated, comprising a treatment tank, a sterilized water supply means, and a jetting means. The treatment tank is configured to accommodate the object to be treated. The sterilized water supply means is configured to supply sterilized water. The jetting means includes an upper nozzle and a side nozzle. The upper nozzle is configured to jet the sterilized water from above the object to be treated accommodated in the treatment tank. The side nozzle is configured to jet the sterilized water from the side of the object to be treated accommodated in the treatment tank. The sterilization apparatus further includes a flow rate changing means capable of reducing the jetting amount of the sterilized water from the upper nozzle without reducing the jetting amount of the sterilized water from the side nozzle.

[0008] According to the present invention, by reducing the jetting amount of the sterilized water from the upper nozzle by the flow rate changing means, it is possible to suppress the concentrated sterilization treatment of the upper part of the object to be treated and suppress the non-uniformity of sterilization.

[0009] Hereinafter, various embodiments of the present invention will be exemplified. The embodiments shown below can be combined with each other.

[0010] Preferably, the jetting means includes an upper line for supplying the sterilized water to the upper nozzle and a side line for supplying the sterilized water to the side nozzle. The flow rate changing means is a valve capable of reducing the flow rate of the sterilized water supplied to the upper nozzle.

[0011] Preferably, a plurality of placement portions for placing the object to be treated are provided in multiple stages in the treatment tank. The upper nozzle is provided above the uppermost placement portion. The side nozzle is provided with a plurality of jet outlets corresponding to the plurality of placement portions.

[0012] Preferably, a water supply means for supplying water into the treatment tank is provided. The sterilized water supply means includes a circulation means and a heating means. The circulation means includes a circulation path and circulates the water in the treatment tank supplied by the water supply means to the ejection means. The heating means supplies heating steam to a heat exchanger provided in the circulation path to heat the water flowing through the circulation path via the heat exchanger, or directly supplies the heating steam to the treatment tank or the circulation path to heat the water ejected from the ejection means. The sterilized water supply means is configured to eject the water heated by the heating means as the sterilized water from the ejection means.

[0013] Preferably, a cooling means and a control means are provided. The cooling means cools the water flowing through the circulation path via the heat exchanger by supplying cold water to the heat exchanger, or directly supplies the cold water to the treatment tank or the circulation path to cool the water ejected from the ejection means. The control means is configured to be able to control the flow rate changing means, the heating means, and the cooling means, and is configured to execute a sterilization step and a cooling step. In the sterilization step, the control means heats the water flowing through the circulation path by controlling the heating means to obtain the sterilized water, and circulates the sterilized water into the treatment tank by the circulation means. In the cooling step, the control means cools the water flowing through the circulation path by controlling the cooling means to obtain cooling water, and circulates the cooling water into the treatment tank by the circulation means. The control means controls the flow rate changing means to reduce the ejection amount of the sterilized water from the upper nozzle in the sterilization step compared to the ejection amount of the cooling water from the upper nozzle in the cooling step.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described. Various characteristic matters shown in the following embodiments can be combined with each other. Also, an invention can be established independently for each characteristic.

[0016] 1. Configuration of the sterilization device 1 First, with reference to FIG. 1, the configuration of the sterilization device 1 according to an embodiment of the present invention will be described. The sterilization device 1 of this embodiment is a device for heating and sterilizing the object to be treated 2 and then cooling it. The type of the object to be treated 2 is not particularly limited, but it is preferably used for foods, particularly retort foods.

[0017] As shown in FIG. 1, the sterilization device 1 of this embodiment includes a treatment tank 3, a water supply means 4, a drainage means 5, a pressurization means 6, an exhaust means 7, a heat exchanger 8, a circulation means 9, a steam supply means 10 as a heating means, a cooling means 11, a drain discharge means 12, and a control means 50. Hereinafter, each configuration will be specifically described.

[0018] The treatment tank 3 is a hollow container for accommodating the object to be treated 2. The shape of the treatment tank 3 is not particularly limited, but in this embodiment, it includes a horizontally arranged cylindrical material. One opening of this cylindrical material is closed, and the other opening can be opened and closed by a door. Therefore, by opening the door, the object to be treated 2 can be put in and taken out of the treatment tank 3, and by closing the door, the opening of the treatment tank 3 can be hermetically closed.

[0019] A temperature sensor (not shown) for detecting the temperature inside the treatment tank 3 and a water level detector (not shown) for detecting the water level inside the treatment tank 3 are provided in the treatment tank 3. The configuration of the water level detector is not particularly limited, but for example, it is an electrode type water level detector.

[0020] In this embodiment, a plurality of trays 13 as placement parts for placing the object to be processed 2 are accommodated in the processing tank 3 over a plurality of levels, and the trays 13 are stacked vertically. The object to be processed 2 is arranged on the tray 13 and is subjected to heat sterilization treatment. The tray 13 is a shallow rectangular container that opens upward, and a large number of openings are formed at least on the bottom surface. The upper and lower trays 13 are stacked so that there are gaps on the side surfaces. However, the object to be processed 2 may be placed on the shelf of the processing tank 3 or on a wagon and accommodated in the processing tank 3.

[0021] The water supply means 4 supplies water into the processing tank 3 via the water supply passage 14. The water supply passage 14 is connected to the bottom of the processing tank 3, and a water supply pump 15 and a water supply valve 16 are provided toward the processing tank 3. By opening the water supply valve 16 with the water supply pump 15 operating, water from the water supply source can be supplied into the processing tank 3, and water can be stored in the processing tank 3. In this embodiment, water is stored in the processing tank 3 up to a set water level at which the object to be processed 2 accommodated in the processing tank 3 is not immersed.

[0022] The drainage means 5 discharges water from the processing tank 3 via the drainage passage 17. The drainage passage 17 is connected to the bottom of the processing tank 3, and a first drainage valve 18 and a check valve 19 are provided. Also, in this embodiment, a bypass drainage passage 20 is provided in the drainage passage 17 so as to connect the front and rear of the first drainage valve 18, and a second drainage valve 21 and a valve 22 are provided in this bypass drainage passage 20. During the operation of the sterilization device 1, the valve 22 is maintained in an open state.

[0023] With such a configuration, the flow rate during drainage from the processing tank 3 can be adjusted by opening either one or both of the first drainage valve 18 and the second drainage valve 21. In this embodiment, when it is desired to drain water at a relatively low flow rate, only the second drainage valve 21 is opened, and when it is desired to drain water more quickly at a higher flow rate, both the first drainage valve 18 and the second drainage valve 21 are opened.

[0024] The pressurizing means 6 supplies pressurized air (in other words, compressed air) into the treatment tank 3 via the pressurizing passage 23. By opening the pressurizing valve 24 provided in the pressurizing passage 23, the pressurized air from the pressurized air source can be supplied into the treatment tank 3, and the inside of the treatment tank 3 can be pressurized to a pressure exceeding the atmospheric pressure.

[0025] The exhaust means 7 discharges gas from the inside of the treatment tank 3 under a pressure exceeding the atmospheric pressure via the exhaust passage 25. The exhaust passage 25 is connected to the upper part of the treatment tank 3, and an exhaust valve 26 and a check valve 27 are provided in order from the side of the treatment tank 3. When the exhaust valve 26 is opened while the inside of the treatment tank 3 is at a pressure exceeding the atmospheric pressure, the gas inside the treatment tank 3 is discharged to the outside via the exhaust passage 25, and the pressure inside the treatment tank 3 can be reduced.

[0026] The circulation means 9 circulates water (circulating water) between the treatment tank 3 and the heat exchanger 8. The circulation means 9 includes a circulation passage 28 and a circulation pump 29. One end of the circulation passage 28 is connected to the bottom of the treatment tank 3, and the other end is connected to the ejection means 30 inside the treatment tank 3 via the circulation pump 29 and the heat exchanger 8 in order. In the case of the illustrated example, the water supply passage 14 and the circulation passage 28 are common pipes on the side of the bottom of the treatment tank 3.

[0027] The ejection means 30 ejects water (sterilized water, cooling water) from the circulation passage 28 toward the object to be treated 2. The ejection means 30 includes an upper line 30a, a pair of side lines 30b, an upper nozzle 30c, and a pair of side nozzles 30d. The upper line 30a connects the circulation passage 28 and the upper nozzle 30c. The side line 30b connects the circulation passage 28 and the side nozzle 30d. Note that an on-off valve 30e as a flow rate changing means is provided in the upper line 30a, and it is possible to switch between a state of supplying water to the upper nozzle 30c and a state of stopping the supply of water to the upper nozzle 30c. That is, the flow rate of the water supplied to the upper nozzle 30c can be reduced by the on-off valve 30e. Specifically, an automatic valve such as a solenoid valve or an air-driven valve is used as the on-off valve 30e.

[0028] The upper nozzle 30c is provided above the uppermost tray 13a in the treatment tank 3, and is configured to eject sterilized water from above the workpiece 2 accommodated in the treatment tank 3 through a plurality of ejection ports 30c1. Further, the side nozzle 30d is provided on the side of the treatment tank 3, and is configured to eject sterilized water from the side of the workpiece 2 accommodated in the treatment tank 3 through a plurality of ejection ports 30d1. Here, in the present embodiment, the side in the treatment tank 3 refers to the position on the cylindrical material side among the front, rear, left, and right side positions of the trays 13 stacked vertically as shown in FIG. 1. However, it is also possible to provide the side nozzle 30d on the opening side. In the example shown in FIG. 1, a pair of left and right side nozzles 30d are provided, but a configuration in which the sterilized water is ejected from either one of them may be adopted. Even when the treatment tank 3 is not cylindrical, the side nozzle 30d is preferably arranged so that the sterilized water is ejected to the side of the workpiece 2 accommodated in the treatment tank 3.

[0029] Note that the shape and number of the upper nozzle 30c itself and its ejection port 30d1 are arbitrary, but it is preferably configured so that the sterilized water is evenly ejected onto the upper part of the workpiece 2 accommodated in the treatment tank 3. Also, the shape and number of the side nozzle 30d itself and its ejection port 30d1 are arbitrary, but it is preferably configured so that the sterilized water is evenly ejected to the side of the workpiece 2 accommodated in the treatment tank 3. In particular, it is preferable that the ejection ports 30d1 of the side nozzle 30d are provided for each of the plurality of trays 13. More specifically, it is preferable that each ejection port 30d1 is arranged at a position where the sterilized water can be ejected between the trays 13 arranged vertically.

[0030] The steam supply means 10 supplies heated steam to the heat exchanger 8 to heat the circulating water flowing through the circulation path 28. The steam supply means 10 includes a steam supply path 31 that supplies steam from a boiler to the heat exchanger 8, and a shut-off valve 32 and a steam supply valve 33 are provided in this steam supply path 31. When the steam supply means 10 supplies steam to the heat exchanger 8, the shut-off valve 32 is maintained in an open state, and the opening degree of the steam supply valve 33 is adjusted. By adjusting the opening degree of the steam supply valve 33, the temperature of the circulating water by the circulation means 9, and thus the temperature in the treatment tank 3, can be adjusted as desired. Specifically, based on the detected temperature of the temperature sensor in the treatment tank 3, the opening degree of the steam supply valve 33 is adjusted. In the present embodiment, the circulation means 9 and the steam supply means 10 constitute a sterilized water supply means for ejecting sterilized water into the treatment tank 3.

[0031] The cooling means 11 supplies cold water to the heat exchanger 8 to cool the circulating water flowing through the circulation path 28. The cooling means 11 includes a cooling tower 34, and the water cooled by the cooling tower 34 is supplied to the heat exchanger 8 via a cold water supply path 36 by a water supply pump 35, and the water after passing through the heat exchanger 8 is returned to the cooling tower 34 via a cold water return path 37. In the case of the illustrated example, the cold water supply path 36 and the steam supply path 31 are common pipes on the side of the heat exchanger 8.

[0032] A cold water supply valve 38 is provided in the cold water supply path 36, while a cold water return valve 39 is provided in the cold water return path 37. The confluence of the cold water supply path 36 and the steam supply path 31 is arranged on the downstream side (the heat exchanger 8 side) of the cold water supply valve 38 and the steam supply valve 33. Further, the cold water supply path 36 on the upstream side (the cooling tower 34 side) of the cold water supply valve 38 and the cold water return path 37 on the downstream side (the cooling tower 34 side) of the cold water return valve 39 are connected by a bypass path 40.

[0033] Therefore, when the water supply pump 35 is operated with the cold water supply valve 38 and the cold water return valve 39 open, cold water can be circulated between the cooling tower 34 and the heat exchanger 8. On the other hand, if the cold water supply valve 38 and the cold water return valve 39 are closed, the flow of cold water to the heat exchanger 8 can be stopped. At this time, the water supply pump 35 may be stopped, but the water supply pump 35 may also be operated to prevent the cooling tower 34 from freezing.

[0034] The drain discharging means 12 discharges the condensed water of the steam supplied to the heat exchanger 8 by the steam supply means 10 to the outside. The drain discharging means 12 is provided on the upstream side (the heat exchanger 8 side) of the cold water return valve 39 in the cold water return path 37, and a drain discharge valve 43, a steam trap 44, and a check valve 45 are sequentially provided in a drain discharge path 42 branched from the cold water return path 37. When steam is supplied to the heat exchanger 8, by opening the drain discharge valve 43, the condensed water of the steam can be dropped downward and discharged to the outside.

[0035] The control means 50 controls each of the above-described means based on detection signals from temperature sensors, water level detectors, elapsed time, and the like. Specifically, the control means 50 controls the water supply pump 15, the water supply valve 16, the first drain valve 18, the second drain valve 21, the pressure valve 24, the exhaust valve 26, the circulation pump 29, the on-off valve 30e, the shut-off valve 32, the steam supply valve 33, the cooling tower 34, the water supply pump 35, the cold water supply valve 38, the cold water return valve 39, and the drain discharge valve 43. Further, temperature sensors, water level detectors, and the like are connected to the control means 50. As will be described later, the control means 50 performs heat sterilization of the object to be treated 2 in the treatment tank 3 and subsequent cooling according to a predetermined procedure (program).

[0036] Note that the control means 50 configured as described above can be specifically configured by, for example, an information processing device including a CPU, a memory (e.g., flash memory), an input unit, and an output unit. Then, the processing by each of the above-described components of the control means 50 configured by the information processing device is performed by the CPU reading and executing a program stored in the memory. As the information processing device, for example, a personal computer, a PLC (programmable logic controller), or a microcomputer is used. However, some functions of the control means 50 may be configured to be executed on the cloud connected by any communication means.

[0037] 2. Operation of the sterilization device 1 The control means 50 controls various valves according to a predetermined procedure (program) to perform heat sterilization of the object to be treated 2 in the treatment tank 3 and subsequent cooling. Specifically, in a state where the object to be treated 2 is accommodated in the treatment tank 3, the control means 50 sequentially executes a water supply process into the treatment tank 3, a transition process of raising the temperature in the treatment tank 3 to the sterilization temperature, a sterilization process of heat sterilizing the object to be treated 2, a cooling process of cooling the object to be treated 2 after heat sterilization, and a drainage process from the treatment tank 3.

[0038] <Water supply process> In the water supply process, the control means 50 supplies water into the treatment tank 3 by the water supply means 4 and stores water up to the set water level in the treatment tank 3. That the water has been stored up to the set water level in the treatment tank 3 can be detected by the water level detector. The set water level is a water level at which none of the objects to be treated 2 in the treatment tank 3 is submerged, and preferably a lower water level at which none of the objects to be treated 2 in the treatment tank 3 is immersed.

[0039] <Transition process> In the transition process, the control means 50 drives the circulation pump 29 of the circulation means 9, circulates water between the treatment tank 3 and the heat exchanger 8, and heats the circulated water by the steam supply means 10 in the heat exchanger 8 to raise the temperature in the treatment tank 3. When the transition time has elapsed since the start of the transition process or when the temperature in the treatment tank 3 has risen to the sterilization temperature, the transition process is terminated.

[0040] Incidentally, immediately after the start of the circulation pump 29, since the water from the circulation pump 29 accumulates in the circulation path 28 and the tray 13, the water level in the treatment tank 3 decreases. Therefore, if water is not appropriately replenished into the treatment tank 3, the stored water in the treatment tank 3 may become insufficient, and there is a risk of air entrainment into the circulation pump 29. Thus, the water level in the treatment tank 3 is monitored by a water level detector, and when the water level in the treatment tank 3 falls below the lower limit water level, water is supplied into the treatment tank 3 by the water supply means 4 until the set water level is reached. In addition, even if such water supply control is performed, immediately after the start of the circulation pump 29, the replenishment of water into the treatment tank 3 may not catch up, the water level in the treatment tank 3 may drop too much, and there is a risk of air entrainment into the circulation pump 29. Therefore, in the present embodiment, when the circulation pump 29 is started, the circulation pump 29 is operated intermittently or the flow rate of the circulating water is gradually increased.

[0041] After the completion of the transfer process, in order to prevent the object to be treated 2 from expanding due to heating and the packaging (such as a retort pouch) from bursting, the pressurizing means 6 and the exhaust means 7 are controlled so that pressurization is performed according to the temperature in the treatment tank 3. Thereafter, the circulation of water by the circulation means 9 and the pressurization in the treatment tank 3 are continued until the end of the cooling process.

[0042] <Sterilization process> In the sterilization process, the control means 50 controls the supply of steam to the heat exchanger 8 by the steam supply means 10 while circulating water between the treatment tank 3 and the heat exchanger 8 by the circulation means 9, thereby heating the circulating water to make it sterilization water, and thus maintaining the inside of the treatment tank 3 at the sterilization temperature and heating the object to be treated 2 in the treatment tank 3 to sterilize it.

[0043] Incidentally, in the sterilization process, the control means 50 closes the on-off valve 30e provided in the upper line 30a so that the sterilization water from the circulation path 28 does not spout from the upper nozzle 30c. That is, in the sterilization process, the control means 50 causes the sterilization water to spout only from the side nozzle 30d via the side line 30b. Thereby, it is possible to avoid the concentrated spouting of the sterilization water onto the object to be treated 2 placed on the uppermost tray 13a. However, the control means 50 may perform control to close the on-off valve 30e at the stage of the transfer process.

[0044] When the inside of the treatment tank 3 reaches the sterilization temperature and the sterilization time has elapsed, the steam supply to the heat exchanger 8 by the steam supply means 10 is stopped, and the sterilization process ends. As described above, in the sterilization process, the pressurizing means 6 and the exhaust means 7 are controlled to maintain the inside of the treatment tank 3 at a set pressure exceeding atmospheric pressure (slightly higher than the saturated steam pressure corresponding to the temperature inside the treatment tank).

[0045] <Cooling process> In the cooling process, the control means 50 cools the circulating water to cooling water by passing cold water through the heat exchanger 8 by the cooling means 11 while circulating water between the treatment tank 3 and the heat exchanger 8 by the circulation means 9, thereby cooling the object to be treated 2 inside the treatment tank 3. In the cooling process, the control means 50 opens the on-off valve 30e to eject the cooling water from the circulation path 28 from both the upper nozzle 30c and the side nozzle 30d through the upper line 30a and the side line 30b.

[0046] When the cooling time has elapsed since the start of the cooling process, or when the temperature inside the treatment tank 3 drops below the cooling temperature, or when a predetermined time has elapsed after dropping below the cooling temperature, the supply of cold water to the heat exchanger 8 by the cooling means 11 is stopped, and the cooling process ends.

[0047] <Drainage process> In the drainage process, drainage is performed from the inside of the treatment tank 3 by the drainage means 5. At this time, with the inside of the treatment tank 3 pressurized by the pressurizing means 6, by opening the first drain valve 18 and the second drain valve 21, water can be quickly discharged from the inside of the treatment tank 3 to the outside. Then, while closing the pressure valve 24 and opening the exhaust valve 26 to return the inside of the treatment tank 3 to atmospheric pressure, the door of the treatment tank 3 can be opened to take out the object to be treated 2 from the inside of the treatment tank 3.

[0048] 3. Operational effects As described above, in the sterilization apparatus 1 of the present embodiment, the on-off valve 30e is provided on the upper line 30a through which the ejection means 30 supplies water to the upper nozzle 30c. Thus, by closing the on-off valve 30e under the control of the control means 50, it is possible to reduce the amount of water ejected from the upper nozzle 30c without reducing the amount of water ejected from the side nozzles 30d. As a specific operation, by closing the on-off valve 30e, it is possible to prevent the sterilizing water from being ejected from the upper nozzle 30c in the sterilization process, and it is possible to avoid the concentrated ejection of the sterilizing water onto the object to be processed 2 placed on the uppermost tray 13a. Thereby, it is possible to prevent quality deterioration of the object to be processed 2 placed on the uppermost tray 13a due to overheating.

[0049] On the other hand, in the cooling process, by opening the on-off valve 30e under the control of the control means 50, it is possible to eject the cooling water from both the upper nozzle 30c and the side nozzles 30d. Thereby, it is possible to efficiently cool the object to be processed 2, and for example, even when some of the nozzles are blocked, it is possible to avoid insufficient cooling.

[0050] 4. Modification Note that the present invention can also be implemented in the following aspects.

[0051] In the above embodiment, the sterilization apparatus 1 includes the heat exchanger 8, and the steam supply means 10 is configured to heat the circulating water flowing through the circulation path 28 via the heat exchanger 8. However, the heat exchanger 8 is not an essential component in the present invention. That is, as shown in FIG. 2, it is also possible to connect the steam supply path 31 of the steam supply means 10 to the circulation path 28 and directly supply steam to the circulation path 28 to heat the circulating water, that is, the water ejected from the ejection means 30.

[0052] Incidentally, at this time, it is preferable that the cooling means 11 is configured to connect a cold water feed path 36 to the primary side of the water feed pump 15 in the water feed path 14 of the water supply means 4 and directly supply the cold water generated by a chiller or the like to the treatment tank 3 or the circulation path 28 via the water feed path 14. That is, in this case, the cooling means 11 cools the water ejected from the ejection means 30 via the circulation path 28 by directly supplying the cold water to the treatment tank 3 or the circulation path 28. And in this case, in order to switch the supply of the normal temperature water and the supply of the cold water by the water supply means 4, it is preferable to provide a cold water valve 46 upstream of the connection position of the cold water feed path 36 and provide a normal temperature water valve 47 on the water feed path 14 side. However, as shown in FIG. 3, it is also possible to connect the cold water feed path 36 of the cooling means 11 to the circulation path 28 and cool the circulating water by supplying the cold water to the circulation path 28. In this case, a cold water valve 46 and a cold water feed valve 38 are installed in the cold water feed path 36.

[0053] Also, although not shown, it is also possible to connect the steam supply path 31 of the steam supply means 10 to the bottom of the treatment tank 3 and heat the water ejected from the ejection means 30 by supplying steam to the bottom of the treatment tank 3.

[0054] In the above embodiment, the steam supply means 10 that supplies steam to the heat exchanger 8 is used as the heating means for heating the water flowing through the circulation path 28. However, it is also possible to use a heat source other than steam as the heating means for heating the water flowing through the circulation path 28.

[0055] In the above-described embodiment, an on-off valve 30e was provided in the upper line 30a as a flow rate changing means for reducing the ejection amount of the sterilizing water from the upper nozzle 30c, and in the sterilization process, no sterilizing water was ejected from the upper nozzle 30c. However, as a flow rate changing means, it is also possible to provide a throttle valve instead of the on-off valve 30e in the upper line 30a, and to reduce the flow rate of the water supplied to the upper nozzle 30c by narrowing the opening degree of the throttle valve. Further, as a flow rate changing means, a three-way valve may be provided at the branch position of the upper line 30a and the side line 30b, and the flow rate of the water supplied to the upper nozzle 30c may be reduced by adjusting the ratio of the water supplied from the circulation path 28 to the upper nozzle 30c.

[0056] In the above-described embodiment, by driving the circulation pump 29 installed in the circulation path 28, sterilizing water or cooling water was ejected from the upper nozzle 30c and the side nozzle 30d via the upper line 30a and the side line 30b connected to the circulation path 28. However, for example, it is also possible to provide two circulation paths, a first circulation path for ejecting sterilizing water or cooling water from the upper nozzle 30c and a second circulation path for ejecting water from the side nozzle 30d, and to drive the circulation pumps provided in each circulation path to eject sterilizing water or cooling water from the upper nozzle 30c and the side nozzle 30d. In this case, even if no valve is provided in the first circulation path, by using the circulation pump provided in the first circulation path as a flow rate changing means and switching the drive of the circulation pump, it is possible to reduce the ejection amount of the sterilizing water from the upper nozzle 30c.

Explanation of Signs

[0057] 1: Sterilizing device 2: Object to be treated 3: Treatment tank 4: Water supply means 5: Drainage means 6: Pressurizing means 7: Exhaust means 8: Heat exchanger 9: Circulation means 10: Steam supply means 11: Cooling means 12: Drain discharge means 13: Tray 13a: Topmost tray 14: Water supply line 15: Water supply pump 16: Water supply valve 17: Drainage path 18: First drain valve 19: Check valve 20: Bypass drainage path 21: Second drain valve 22: Valve 23: Pressurization path 24: Pressurization valve 25: Exhaust path 26: Exhaust valve 27: Check valve 28: Circulation path 29: Circulation pump 30: Jetting means 30a: Upper line 30b: Side line 30c: Upper nozzle 30c1: Jet outlet 30d: Side nozzle 30d1: Jet outlet 30e: On-off valve 31: Steam supply line 32: Shut-off valve 33: Steam supply valve 34: Cooling tower 35: Water supply pump 36: Cold water supply path 37: Cold water return path 38: Cold water supply valve 39: Cold water return valve 40: Bypass path 42: Drain discharge path 43: Drain discharge valve 44: Steam trap 45: Check valve 46: Cold water valve 47: Normal temperature water valve 50: Control means

Claims

【Claim 1】 A sterilization device for sterilizing an object to be treated, comprising: a treatment tank, a water supply means, a sterilized water supply means, a jetting means, and a cooling means; the treatment tank is configured to accommodate the object to be treated; the water supply means is configured to supply water into the treatment tank; the sterilized water supply means includes a circulation means and a heating means; the circulation means includes a circulation path and circulates the water in the treatment tank supplied by the water supply means to the jetting means; the heating means is configured to heat the water flowing through the circulation path via the heat exchanger by supplying heating steam to the heat exchanger provided in the circulation path, or to directly supply the heating steam to the treatment tank or the circulation path to heat the water jetted from the jetting means; the sterilized water supply means is configured to jet the water heated by the heating means as sterilized water from the jetting means; the jetting means includes an upper nozzle and a side nozzle; the upper nozzle is configured to jet the sterilized water from above the object to be treated accommodated in the treatment tank; the side nozzle is configured to jet the sterilized water from the side of the object to be treated accommodated in the treatment tank; the cooling means is configured to cool the water flowing through the circulation path via the heat exchanger by supplying cold water to the heat exchanger, or to directly supply the cold water to the treatment tank or the circulation path to cool the water jetted from the jetting means; further comprising a flow rate changing means and a control means; the flow rate changing means is capable of reducing the jetting amount of the sterilized water from the upper nozzle without reducing the jetting amount of the sterilized water from the side nozzle; the control means is configured to be able to control the flow rate changing means, the heating means and the cooling means, and is configured to execute a sterilization step and a cooling step; in the sterilization step, the control means controls the heating means to heat the water flowing through the circulation path to be the sterilized water, and circulates the sterilized water into the treatment tank by the circulation means; in the cooling step, the control means controls the cooling means to cool the water flowing through the circulation path to be cooling water, and circulates the cooling water into the treatment tank by the circulation means. The sterilization device, wherein the control means controls the flow rate changing means to reduce the ejection amount of the sterilizing water from the upper nozzle in the sterilization step to be lower than the ejection amount of the cooling water from the upper nozzle in the cooling step. **Claim 2** The sterilization device according to claim 1, wherein the ejection means includes an upper line for supplying the sterilizing water to the upper nozzle and a side line for supplying the sterilizing water to the side nozzle. The sterilization device, wherein the flow rate changing means is a valve capable of reducing the flow rate of the sterilizing water supplied to the upper nozzle. **Claim 3** The sterilization device according to claim 1 or claim 2, wherein a plurality of placement portions for placing the object to be treated are provided in multiple stages in the treatment tank, the upper nozzle is provided above the uppermost placement portion, and the side nozzle is provided with a plurality of ejection ports corresponding to the plurality of placement portions.

Images