Heat sterilization device, object to be sterilized, and heat sterilization method

Abstract

This heat sterilization apparatus 100 has an accommodation space 1d for accommodating therein an object Rp to be sterilized by heat sterilization with a high-temperature fluid Hth, and includes a sterilization tank 1 to which is supplied a high-temperature fluid Hth for heat sterilizing the object Rp and a cooling water Cw for cooling the object Rp that has been heat sterilized with the high-temperature fluid Hth. The heat sterilization apparatus 100 includes a control unit 12 that performs medium-temperature water heat recovery control to recover heat from the sterilization tank 1 after heat sterilization, using medium-temperature water Htm that has a temperature higher than the cooling water Cw and lower than the high-temperature fluid Hth and that is generated separately from the high-temperature fluid Hth, before cooling the object Rp with the cooling water Cw.

Description

[Technical field]

[0001] The present invention relates to a heat sterilization device, an object to be sterilized, and a heat sterilization method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a heat sterilization device for heat sterilizing an object to be sterilized. For example, this heat sterilization device is disclosed in Japanese Patent Application Laid-Open No. 2000-69948.

[0003] The above-mentioned Japanese Patent Application Laid-Open No. 2000-69948 discloses a cooking sterilization device (heat sterilization device) for heat sterilizing an object to be sterilized (object to be sterilized).

[0004] The cooking sterilization apparatus of JP 2000-69948 A includes a sterilization tank, a hot water tank, a cold water tank, a water supply tank, a spray nozzle, a heat exchanger, and a control device (control unit). The sterilization tank contains objects to be sterilized. The hot water tank is a tank for storing hot water to be sprayed from the spray nozzle. In order to heat sterilize the objects contained in the sterilization tank, the spray nozzle heats the hot water supplied from the hot water tank to a heat sterilization temperature and sprays it into the sterilization tank as jet water (high-temperature fluid). Here, in the cooking sterilization apparatus, after heat sterilization with the high-temperature jet water, the hot water supplied from the hot water tank is cooled by heat exchange with water supplied from the water supply tank in the heat exchanger so that the temperature of the hot water supplied from the hot water tank is lowered to a predetermined temperature. Then, in the cooking sterilization apparatus, the hot water that has been lowered to the predetermined temperature is collected in the hot water tank. Thereafter, in the food sterilization apparatus, cooling water supplied from a cold water tank is sprayed as a jet of water into the sterilization tank in order to cool the heated objects to be sterilized and the sterilization tank after the heat sterilization. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-69948 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the cooking sterilization apparatus of JP 2000-69948 A, the temperature of the high-temperature hot water that has been heated to the sterilization temperature is lowered by heat exchange with low-temperature cold water in the heat exchanger before being collected in the hot water tank. Therefore, the cooking sterilization apparatus of JP 2000-69948 A has a problem that it takes a long time to heat the hot water (high-temperature fluid) to the sterilization temperature during the next sterilization after heat recovery.

[0007] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a heat sterilization device, an object to be sterilized, and a heat sterilization method that can suppress an increase in the time required to raise the temperature of a high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery. [Means for solving the problem]

[0008] A heat sterilization apparatus according to a first aspect of the present invention includes a sterilization tank having an accommodation space for accommodating an object to be sterilized by heat sterilization with a high-temperature fluid, and supplied with a high-temperature fluid for heat sterilizing the object and cooling water for cooling the object that has been heat sterilized by the high-temperature fluid; A medium temperature water tank consisting of a single tank; Before cooling the object to be sterilized with cooling water, The fish were stored in a single medium temperature water tank. A hot fluid is generated separately from the cooling water, and the temperature of the hot fluid is higher than that of the cooling water and lower than that of the hot fluid. The water was stored in a single medium temperature tank. The control unit performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization by using medium-temperature water.

[0009] In the heat sterilization apparatus according to the first aspect of the present invention, as described above, A medium temperature water tank consisting of a single tank; Before cooling the object to be sterilized with cooling water, The fish were stored in a single medium temperature water tank. A hot fluid is generated separately from the cooling water, and the temperature of the hot fluid is higher than that of the cooling water and lower than that of the hot fluid. The water was stored in a single medium temperature tank.A control unit is provided that performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium-temperature water. This allows the temperature of the high-temperature fluid to be prevented from decreasing by recovering heat from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, so that the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery can be prevented from becoming long. In addition, before cooling the sterilization object with cooling water, the sterilization tank after heat sterilization can be cooled with medium-temperature water having a temperature higher than the temperature of the cooling water, so that a sudden temperature change (sudden temperature drop) in the sterilization tank after heat sterilization can be prevented. As a result, the degree of expansion and contraction of the sterilization tank can be reduced, so that, unlike the case where large expansion and contraction are repeated, metal fatigue due to thermal stress can be prevented from increasing, and the durability of the sterilization tank can be prevented from decreasing (shortening of life).

[0010] In the heat sterilization apparatus according to the first aspect, the control unit is preferably configured to perform the medium temperature water heat recovery control in a state where the high temperature fluid after heat sterilization is discharged from the sterilization tank. With this configuration, heat recovery using the high temperature fluid is performed simply by discharging the high temperature fluid, and therefore a dedicated heat exchanger and water tank for heat recovery using the high temperature fluid are not required, and it is possible to suppress an increase in size of the apparatus due to heat recovery using the high temperature fluid.

[0011] In the heat sterilization apparatus according to the first aspect, preferably, before cooling the object to be sterilized with the cooling water, the control unit: A single-tank medium-temperature water tank The medium-temperature water heat recovery control is performed to recover heat from the sterilization tank after heat sterilization using the medium-temperature water supplied from the A single-tank medium-temperature water tank With this configuration, by storing medium-temperature water in the medium-temperature water tank, the medium-temperature water can be easily supplied to the sterilization tank after heat sterilization during heat recovery, and by storing the medium-temperature water used in heat recovery in the medium-temperature water tank without discharging it, the recovered heat can be easily reused.

[0012] In this case, preferably, the control unit is configured to control the medium-temperature water heat recovery control to control the medium-temperature water heat recovery control before the object to be sterilized is heated by the high-temperature fluid. A single-tank medium-temperature water tank The apparatus is configured to perform preheating control to preheat the sterilization tank using the medium-temperature water stored in the sterilization tank. With this configuration, the initial temperature of the sterilization tank at the start of heat sterilization can be increased by preheating the sterilization tank using the medium-temperature water heated by using heat recovery, so that the amount of heat given to the high-temperature fluid when raising the temperature of the high-temperature fluid to the temperature for heat sterilization can be reduced compared to the case where preheating is not performed. In other words, by using the medium-temperature water, the heat recovered can be effectively used for preheating. As a result, when preheating is performed, the thermal energy required in the heat sterilization device can be reduced, and the amount of (high-temperature) steam used to raise the temperature of the high-temperature water can be reduced accordingly.

[0013] In the heat sterilization apparatus configured to perform preheating control for preheating the sterilization tank using medium temperature water, the control unit preferably A single-tank medium-temperature water tank and a first connection path that connects the first and second intermediate temperature water in the sterilization tank after the heat recovery, A single-tank medium-temperature water tank The intermediate temperature water tank is configured to perform control to recover and store intermediate temperature water in the intermediate temperature water tank and control to supply intermediate temperature water to the sterilization tank via the first connection path during preheating. With this configuration, it is possible to easily store intermediate temperature water after heat recovery in the intermediate temperature water tank and supply intermediate temperature water from the intermediate temperature water tank to the sterilization tank during preheating, using the first connection path.

[0014] In the heat sterilization apparatus, the control unit is configured to perform preheating control to preheat the sterilization tank using medium temperature water, preferably, in each of the preheating of the sterilization tank and the heat recovery of the sterilization tank, A single-tank medium-temperature water tankThe apparatus is configured to control the discharge of the medium-temperature water supplied from the sterilization tank toward the object to be sterilized. With this configuration, when the sterilization tank is preheated, the temperature of the medium-temperature water is lowered by applying the discharged medium-temperature water to the object to be sterilized, and the medium-temperature water with the lowered temperature can be applied to the sterilization tank, so that a sudden change in temperature of the low-temperature sterilization tank during preheating can be suppressed. Furthermore, when the heat recovery of the sterilization tank is performed, the temperature of the medium-temperature water is increased by applying the discharged medium-temperature water to the object to be sterilized, and the medium-temperature water with the increased temperature can be applied to the sterilization tank, so that a sudden change in temperature of the high-temperature sterilization tank during heat recovery can be suppressed. As a result, a decrease in the durability of the sterilization tank caused by an increase in thermal stress due to a sudden temperature change can be suppressed in each of the preheating of the sterilization tank and the heat recovery of the sterilization tank.

[0015] The heat sterilization apparatus according to the first aspect preferably further comprises a high-temperature water tank for recovering and storing high-temperature water, which is a high-temperature fluid after heat sterilization stored in the sterilization tank, and a second connection path connecting the sterilization tank and the high-temperature water tank, and the control unit is configured to recover the high-temperature water discharged from the sterilization tank after the heat sterilization of the object to be sterilized into the high-temperature water tank via the second connection path, and then perform medium-temperature water heat recovery control of the sterilization tank. With this configuration, by recovering the high-temperature water in the sterilization tank via the dedicated second connection path connecting the sterilization tank and the high-temperature water tank, it is possible to prevent the heat of the high-temperature water from being taken away after the heat sterilization control, and therefore it is possible to suppress a decrease in the temperature of the high-temperature water recovered in the high-temperature water tank.

[0016] In the heat sterilization apparatus having the above-mentioned medium-temperature water tank, preferably, a heat transfer fluid supply unit that supplies a heat transfer fluid heated by medium-temperature water; A single-tank medium-temperature water tankand a heat exchanger that exchanges heat between the medium-temperature water stored in the heat exchanger and a heat transfer fluid supplied from a heat transfer fluid supply unit, and the control unit is configured to control the supply of the heat transfer fluid, the temperature of which has been increased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank in preheating of the sterilization tank, and to control the supply of the heat transfer fluid, the temperature of which has been decreased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank in heat recovery of the sterilization tank. With this configuration, the preheating temperature can be lowered in preheating of the sterilization tank compared to the case where medium-temperature water is directly supplied to the sterilization tank, and therefore a sudden temperature change in the sterilization tank can be further suppressed.

[0017] In the heat sterilization apparatus according to the first aspect, preferably, a heat transfer fluid supply unit that supplies a heat transfer fluid heated by medium temperature water; A single-tank medium-temperature water tank and a heat exchanger that exchanges heat between the medium-temperature water stored in the heat exchanger and a heat transfer fluid supplied from a heat transfer fluid supply unit, and the control unit is configured to control the supply of the heat transfer fluid, the temperature of which has been increased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank in preheating of the sterilization tank, and to control the supply of the heat transfer fluid, the temperature of which has been decreased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank in heat recovery of the sterilization tank. With this configuration, the circulation paths used in each of the heat sterilization control and the cooling control can be used in common in the heat recovery control, thereby preventing the structure from becoming complicated and large-sized due to an increase in the paths of the heat sterilization device.

[0020] The first aspect of this invention 2 The heat sterilization method according to the above aspect includes the steps of: supplying a high-temperature fluid to a sterilization tank where heat sterilization is performed with the high-temperature fluid to heat sterilize an object to be sterilized in the sterilization tank; recovering heat from the sterilization tank after heat sterilization using medium-temperature water stored in a single-tank medium-temperature water tank, the medium-temperature water having a temperature higher than that of the cooling water and lower than that of the high-temperature fluid, before cooling the object to be sterilized with cooling water, the medium-temperature water being generated separately from the high-temperature fluid and stored in the single-tank medium-temperature water tank; and cooling the object to be sterilized that has been heat sterilized with cooling water after the heat recovery from the sterilization tank.

[0021] The first aspect of this invention 2 In the heat sterilization method according to the aspect, as described above, before cooling the sterilization object with cooling water, the heat recovery step of the sterilization tank after heat sterilization is performed using medium-temperature water, which is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid and is stored in a medium-temperature water tank consisting of a single tank, and which is stored in the medium-temperature water tank consisting of a single tank, and the heat recovery step of cooling the sterilized object with cooling water after the heat recovery from the sterilization tank. As a result, by performing heat recovery from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, it is possible to prevent the temperature of the high-temperature fluid from decreasing, and therefore it is possible to provide a heat sterilization method that can suppress an increase in the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery, and that can suppress a decrease in the durability of the sterilization tank caused by an increase in thermal stress due to a sudden temperature change.

[0022] The above 2 In the heat sterilization method according to the aspect, preferably, the method further comprises a step of preheating the sterilization tank using the medium temperature water heated during heat recovery of the sterilization tank before supplying the high temperature fluid for heat sterilization of the object to be sterilized to the sterilization tank. By configuring in this way, the initial temperature of the sterilization tank at the start of heat sterilization can be increased by preheating the sterilization tank using the medium temperature water heated by using heat recovery, so that the amount of heat given to the high temperature fluid during heating to raise the temperature of the high temperature fluid to the temperature for heat sterilization can be reduced compared to the case where preheating is not performed. In other words, by using the medium temperature water, the heat recovered can be effectively used for preheating. As a result, when preheating is performed, the increase in thermal energy required in the heat sterilization device can be suppressed. Effect of the Invention

[0023] According to the present invention, as described above, it is possible to prevent the time required for raising the temperature of the high-temperature fluid to the heat sterilization temperature from becoming long during the next heat sterilization after heat recovery. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing a heat sterilization device of the present embodiment. [Diagram 2] FIG. 1 is a block diagram showing an overview of using heat recovered in heat recovery for a preheating step of the next heat sterilization control in the heat sterilization control of the heat sterilization device of this embodiment. [Diagram 3] 4 is a graph showing the relationship between time of heat sterilization control by the heat sterilization device of the present embodiment and temperature change in the sterilization tank. [Figure 4] 10 is a graph showing the relationship between time of heat sterilization control by the heat sterilization device of the comparative example and temperature change in the sterilization tank. [Diagram 5] FIG. 2 is a schematic diagram showing the preparation of high-temperature water performed before the carrying-in process of the heat sterilization apparatus of the present embodiment. [Figure 6] FIG. 2 is a schematic diagram showing preparation of medium-temperature water performed before the carrying-in process of the heat sterilization apparatus of the present embodiment. [Figure 7] FIG. 2 is a schematic diagram showing a carrying-in process in the heat sterilization control of the heat sterilization device of the present embodiment. [Figure 8] FIG. 8 is a schematic diagram showing a medium-temperature water injection step in a preheating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the medium-temperature water injection step following the carry-in step shown in FIG. [Figure 9] FIG. 9 is a schematic diagram showing a medium-temperature water circulation step in a preheating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the medium-temperature water circulation step subsequent to the medium-temperature water injection step shown in FIG. 8. [Figure 10] FIG. 10 is a schematic diagram showing a medium-temperature water recovery step in a preheating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the medium-temperature water recovery step subsequent to the medium-temperature water circulation step shown in FIG. [Figure 11] 11 is a schematic diagram showing a high-temperature water injection step of the object heating step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the high-temperature water injection step following the medium-temperature water recovery step shown in FIG. 10. [Figure 12]12 is a schematic diagram showing the temperature increase step and the heat sterilization step of the object heating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the temperature increase step following the high-temperature water injection step shown in FIG. 11. [Figure 13] This is a schematic diagram showing a process of recovering heat by recovering high-temperature water in a high-temperature water tank in the high-temperature hydrothermal recovery process in the heat sterilization control of the heat sterilization device of this embodiment, and shows the high-temperature hydrothermal recovery process following the temperature increase process shown in Figure 12. [Figure 14] 14 is a schematic diagram showing the medium-temperature water injection process of the medium-temperature water heat recovery process in the heat sterilization control of the heat sterilization device of this embodiment, and shows the medium-temperature water injection process following the high-temperature water heat recovery process shown in FIG. 13. [Figure 15] 15 is a schematic diagram showing the medium temperature water circulation step of the medium temperature water heat recovery step in the heat sterilization control of the heat sterilization device of this embodiment, and shows the medium temperature water circulation step subsequent to the medium temperature water injection step shown in FIG. 14. [Figure 16] FIG. 16 is a schematic diagram showing a medium temperature water recovery step of the medium temperature water heat recovery process in the heat sterilization control of the heat sterilization device of this embodiment, and shows the medium temperature water recovery step subsequent to the medium temperature water circulation step shown in FIG. [Figure 17] FIG. 17 is a schematic diagram showing a cooling water injection step of the object cooling step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the cooling water injection step subsequent to the medium-temperature water recovery step shown in FIG. 16. [Figure 18] FIG. 18 is a schematic diagram showing a cooling step of the object cooling step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the cooling step subsequent to the cooling water injection step shown in FIG. 17. [Figure 19] 19 is a schematic diagram showing a cooling water recovery step of the object cooling step in the heat sterilization control of the heat sterilization device of the present embodiment, and is a diagram showing the cooling water recovery step subsequent to the cooling step shown in FIG. 18. [Figure 20] FIG. 2 is a schematic diagram showing a discharge process in the heat sterilization control of the heat sterilization device of the present embodiment. [Figure 21] FIG. 11 is a graph comparing a graph of heat sterilization control by a heat sterilization device of a comparative example with a graph of heat sterilization control by the heat sterilization device of the present embodiment. [Figure 22] 1 is a flowchart showing a heat sterilization method using the heat sterilization device of the present embodiment. [Figure 23] FIG. 11 is a schematic diagram showing a state of an object heating process of a hot water storage type heat sterilization device of a first modified example of this embodiment. [Figure 24] FIG. 11 is a schematic diagram showing a state of an object heating process of a steam-type heat sterilization device according to a second modified example of this embodiment. [Diagram 25] FIG. 13 is a schematic diagram showing a heat sterilization device according to a third modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] The configuration of a heat sterilization apparatus 100 according to this embodiment will be described with reference to Figs. 1 to 22.

[0027] (heat sterilizer) As shown in Fig. 1, the heat sterilization device 100 according to this embodiment is a spray-type device that heats a retort pouch Rp containing food by using high-temperature water Hth to heat and sterilize the food and the retort pouch Rp. The retort pouch Rp containing the food is an example of the "object to be sterilized" in the claims. The high-temperature water Hth is an example of the "high-temperature fluid" in the claims.

[0028] As shown in FIG. 1 , the spray-type heat sterilization device 100 according to this embodiment includes a sterilization tank 1, a spray nozzle 2, a high-temperature water tank 3, a medium-temperature water tank 4, a circulation path 5, a supply path 6, a discharge path 7, a discharge path 8, a supply path 9, a discharge path 10, a heat exchanger 11, and a control unit 12.

[0029] (sterilization tank) The sterilization tank 1 is a sealed container that heat-sterilizes the retort pouch Rp with high-temperature water Hth and cools the heat-sterilized retort pouch Rp with cooling water Cw. Medium-temperature water Htm is supplied to the sterilization tank 1 to preheat the retort pouch Rp and recover heat. Here, the medium-temperature water Htm is water that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth. The preheating and heat recovery using the medium-temperature water Htm will be described in detail later. The sterilization tank 1 includes a loading / unloading door 1a, a temperature sensor 1b, a water level sensor 1c, a storage space 1d, and a storage space 1e.

[0030] The carry-in / out door 1a is a door that is opened and closed by a user when carrying trays Tr on which multiple retort pouches Rp are placed, stacked in multiple layers, into the sterilization tank 1 and when carrying them out of the sterilization tank 1. The temperature sensor 1b is a sensor for measuring the temperature in the sterilization tank 1. The water level sensor 1c is a sensor for measuring the water levels of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw stored in the storage space 1e. The storage space 1d is a space for storing the retort pouches Rp that are to be heat-sterilized with the high-temperature water Hth. The storage space 1e is a space for storing the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw when performing preheating, heat sterilization, heat recovery, and cooling. The storage space 1e is a space below the lowest tray Tr of the stacked trays Tr in the storage space 1d.

[0031] (Spray nozzle) The spray nozzle 2 in the spray-type heat sterilization device 100 according to this embodiment is configured to eject each of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw into the sterilization tank 1. The spray nozzle 2 includes a plurality of injection ports 2a. Each of the plurality of injection ports 2a is arranged in accordance with the position of the trays Tr stacked in a plurality of stages. As a result, each of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw ejected from the spray nozzle 2 is ejected toward the retort pouch Rp placed on the tray Tr. A plurality of spray nozzles 2 configured in this manner are arranged in the sterilization tank 1.

[0032] (High temperature water tank) As shown in FIG. 1, the high-temperature water tank 3 is a tank that collects and stores high-temperature water Hth, which is a high-temperature fluid after heat sterilization stored in the sterilization tank 1. The high-temperature water tank 3 has a hot water storage space capable of storing high-temperature water Hth with a volume equal to the combined volume of the storage space 1e, the circulation path 5, and the supply path 6. The high-temperature water tank 3 includes a temperature sensor 3a and a water level sensor 3b. The temperature sensor 3a is a sensor for measuring the temperature inside the high-temperature water tank 3. The water level sensor 3b is a sensor for measuring the water level of the high-temperature water Hth stored in the hot water storage space.

[0033] (Medium temperature water tank) Here, the medium-temperature water tank 4 in this embodiment is a tank that collects and stores the medium-temperature water Htm stored in the sterilization tank 1 after preheating and after heat recovery. The medium-temperature water tank 4 has a medium-temperature water storage space capable of storing the medium-temperature water Htm with a volume equal to the combined volume of the storage space 1e, the circulation path 5, and the supply path 6. As shown in FIG. 1, the medium-temperature water tank 4 includes a temperature sensor 4a and a water level sensor 4b. The temperature sensor 4a is a sensor for measuring the temperature inside the medium-temperature water tank 4. The water level sensor 4b is a sensor for measuring the water level of the medium-temperature water Htm stored in the medium-temperature water storage space.

[0034] (Circulation route) 1, the circulation path 5 is a path that returns each of the cooling water Cw, high-temperature water Hth, and medium-temperature water Htm discharged from the sterilization tank 1 to the inside of the sterilization tank 1 via a heat exchanger 11. The circulation path 5 includes a discharge pipe 5a, a discharge pipe 5b, an upstream pipe 5c, a downstream pipe 5d, a temperature sensor 5e, a circulation pump 5f, and a flow path switching valve 5g.

[0035] The discharge pipe 5a and the discharge pipe 5b are pipes for discharging the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm stored in the storage space 1e. The upstream pipe 5c connects the heat exchanger 11 to the discharge pipe 5a and the discharge pipe 5b. The downstream pipe 5d connects the heat exchanger 11 to the sterilization tank 1. The circulation pump 5f is a pump for discharging the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm discharged from the sterilization tank 1 and circulating them to the sterilization tank 1. The circulation pump 5f is a pump for returning the high temperature water Hth discharged from the sterilization tank 1 to the high temperature water tank 3. The circulation pump 5f is a pump for returning the medium temperature water Htm discharged from the sterilization tank 1 to the medium temperature water tank 4. The flow path switching valve 5g is a valve for switching the flow paths through which the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm flow.

[0036] (Supply Channel) The supply path 6 is a pipeline branching off from the circulation path 5 to supply high temperature water Hth to the high temperature water tank 3. The supply path 6 is also a pipeline branching off from the circulation path 5 to supply medium temperature water Htm to the medium temperature water tank 4. The supply path 6 includes a common pipeline 6a, branch pipelines 6b, branch pipelines 6c, a flow path switching valve 6d, and a flow path switching valve 6e. The common pipeline 6a is connected to the circulation path 5 and is a common pipeline for the high temperature water tank 3 and the medium temperature water tank 4. The branch pipeline 6b branches off from the common pipeline 6a and is connected to the high temperature water tank 3. The branch pipeline 6c branches off from the common pipeline 6a and is connected to the medium temperature water tank 4.

[0037] (Excretion route) The discharge path 7 is a pipe connecting the high temperature water tank 3 and the discharge path 8 in order to allow the high temperature water Hth in the high temperature water tank 3 to flow into the circulation path 5. The discharge path 7 includes a connecting pipe 7a and a flow path switching valve 7b. The discharge path 8 is a pipe connecting the medium temperature water tank 4 and the circulation path 5 in order to allow the medium temperature water Htm in the medium temperature water tank 4 to flow into the circulation path 5. The discharge path 8 includes a connecting pipe 8a and a flow path switching valve 8b.

[0038] Here, the circulation path 5, the common pipe 6a and the branch pipe 6c of the supply path 6, and the connection pipe 8a of the discharge path 8 are an example of a "first connection path" in the claims, which connects the sterilization tank 1 and the medium-temperature water tank 4 to each other. The circulation path 5, the common pipe 6a and the branch pipe 6b of the supply path 6, and the connection pipe 8a of the discharge path 8 are an example of a "second connection path" in the claims, which connects the sterilization tank 1 and the high-temperature water tank 3 to each other. In addition, cooling water Cw supplied from a cooling water source 200 provided in the factory in which the heat sterilization device 100 is installed flows into the circulation path 5. The cooling water Cw is supplied to a portion of the upstream pipe 5c upstream of the circulation pump 5f.

[0039] (Supply Channel) The supply path 9 is a path that connects the heat exchanger 11 to each of a steam inlet 301 of a boiler facility and a cooling water inlet 401 of a cooling water source provided in a factory in which the heat sterilization apparatus 100 is installed. The supply path 9 includes a common pipe 9a, a connection pipe 9b, a flow path switching valve 9c, and a flow path switching valve 9d.

[0040] (Excretion route) The discharge path 10 is a path that connects the heat exchanger 11 to the steam drain 302 and the cooling water outlet 402, which are provided in the factory in which the heat sterilization apparatus 100 is installed. The discharge path 10 includes a common pipe 10a, a connection pipe 10b, a flow path switching valve 10c, a flow path switching valve 10d, and a steam trap 10e.

[0041] (heat exchanger) 1, the heat exchanger 11 is a member that heats each of the cooling water Cw and the high-temperature water Hth by exchanging heat between each of the cooling water Cw and the high-temperature water Hth flowing through the circulation path 5 and steam flowing in from the steam inlet 301. The heat exchanger 11 is a member that cools the cooling water Cw by exchanging heat between the cooling water Cw flowing through the circulation path 5 and the cooling water flowing in from the cooling water inlet 401.

[0042] (Control unit) The control unit 12 is configured to control the heat sterilization apparatus 100. The control unit 12 includes a CPU (Central Processing Unit), a storage unit such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive), and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit stores a heat sterilization program that controls the loading and unloading of the retort pouch Rp in the heat sterilization apparatus 100, and controls the heat sterilization, cooling, preheating, and heat recovery of the retort pouch Rp.

[0043] The control unit 12 is electrically connected to the temperature sensor 1b, the water level sensor 1c, the temperature sensor 3a, the water level sensor 3b, the temperature sensor 4a, the water level sensor 4b, the temperature sensor 5e, the circulation pump 5f, the flow path switching valve 5g, the flow path switching valve 6d, the flow path switching valve 6e, the flow path switching valve 7b, the flow path switching valve 8b, the flow path switching valve 9c, the flow path switching valve 9d, the flow path switching valve 10c, and the flow path switching valve 10d. The control unit 12 is also electrically connected to not only the above-mentioned sensors, but also flow rate measurement sensors and pressure sensors.

[0044] The control unit 12 controls the loading and unloading of the retort pouch Rp, and controls the thermal sterilization, cooling, preheating, and heat recovery of the retort pouch Rp, based on necessary measurement information from various sensors.

[0045] (Outline of operation control of the heat sterilization device of this embodiment) First, an overview (concept) of the operation control of the heat sterilization device 100 of this embodiment (hereinafter referred to as "heat sterilization control") will be described with reference to FIG.

[0046] As shown in Fig. 2, the heat sterilization control of this embodiment includes a preheating process, an object heating process, a high-temperature water heat recovery process, a medium-temperature water heat recovery process, and an object cooling process as a series of processes. The heat sterilization control of this embodiment reduces the total amount of heat energy required when the heat sterilization control including the series of processes is performed multiple times.

[0047] Specifically, a preheating process is performed before the object heating process to heat the low-temperature sterilization tank 1 and the retort pouch Rp (object to be sterilized). In this preheating process, the amount of heat taken by the sterilization tank 1 from the high-temperature water Hth during the object heating process is reduced, and the retort pouch Rp is more likely to be heated to the heat sterilization temperature Tst by the high-temperature water Hth.

[0048] Here, in the heat sterilization control of this embodiment, as shown in Fig. 2, the medium-temperature water Htm, whose temperature has been increased (to about 90°C) by recovering heat in the medium-temperature water heat recovery process from the high-temperature sterilization tank 1 and the retort pouch Rp (object to be sterilized) after heat sterilization in the first heat sterilization control, is used for preheating in the second heat sterilization control, and the temperature of the medium-temperature water Htm is reduced from about 90°C to about 50°C. Then, the heat recovered in the second heat sterilization control is used for preheating in the third heat sterilization control, and similar use of the recovered heat is repeated from the second time onwards.

[0049] As a result, the thermal energy required for preheating is obtained from the high-temperature sterilization tank 1 and retort pouch Rp (object to be sterilized), which would normally be discharged via the cooling water Cw in the object cooling process. This reduces the total amount of thermal energy required when heat sterilization control including a series of processes is performed multiple times.

[0050] (Details of Heat Sterilization Control in This Embodiment) Hereinafter, with reference to Figs. 3 to 22, details of the heat sterilization control including the preheating step and the medium-temperature water heat recovery step of this embodiment will be described.

[0051] As shown in Fig. 3, the heat sterilization control according to this embodiment is a control that sequentially performs a carry-in process, a preheating process (preheating control), an object heating process (sterilization object heat sterilization control), a high-temperature water heat recovery process (high-temperature water heat recovery control), a medium-temperature water heat recovery process (medium-temperature water heat recovery control), an object cooling process (sterilization object cooling control), and a carry-out process. The preheating process includes each of a medium-temperature water injection process, a medium-temperature water circulation process, and a medium-temperature water recovery process. The object heating process includes each of a high-temperature water injection process, a temperature increase process, and a heat sterilization process. The medium-temperature water heat recovery process includes each of a medium-temperature water injection process, a medium-temperature water circulation process, and a medium-temperature water recovery process. The object cooling process includes each of a cooling water supply process, a cooling process, and a cooling water recovery process.

[0052] In contrast to the heat sterilization control of this embodiment including the above-mentioned steps, the heat sterilization control of the comparative example (corresponding to the conventional example) shown in Fig. 4 performs control related to the retort pouch carry-in and carry-out steps, and control related to the retort pouch heat sterilization step, high-temperature hydrothermal heat recovery step, and cooling step. That is, the heat sterilization device performing the heat sterilization control of this comparative example does not include a medium temperature tank that stores medium temperature water, and does not perform control of preheating and heat recovery using medium temperature water.

[0053] In this way, among the above-mentioned multiple steps of the heat sterilization control of the present embodiment, the preheating step and the medium temperature water heat recovery step are configurations that are different from the heat sterilization control of the comparative example. Hereinafter, they will be described in detail.

[0054] <Preparing hot water> First, as shown in FIG. 5, before the carrying-in step, high-temperature water Hth is prepared in advance.

[0055] Specifically, the control unit 12 performs control to form the hot water preparation circuit Ci1 by closing the flow path switching valves 5g, 6e, and 8b, and opening the flow path switching valves 6d and 7b. The control unit 12 performs control to prepare high-temperature water Hth by heating the circulating coolant Cw by heat exchange with steam in the heat exchanger 11 while circulating the coolant Cw supplied from the coolant source 200 through the hot water preparation circuit Ci1 by the circulation pump 5f. Here, the hot water preparation circuit Ci1 has an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, a branch pipe 6b, a connection pipe 7a, and a connection pipe 8a. In the hot water preparation circuit Ci1, the coolant Cw flows in the order of the connection pipe 7a, the connection pipe 8a, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6b.

[0056] <Preparing medium temperature water> Furthermore, as shown in FIG. 6, prior to the carrying-in process, the medium-temperature water Htm is prepared in advance.

[0057] Specifically, after preparing high-temperature water Hth, the control unit 12 closes the flow path switching valves 5g, 6d, and 7b and opens the flow path switching valves 6e and 8b to form the medium-temperature water preparation circuit Ci2. The control unit 12 then circulates the cooling water Cw supplied from the cooling water source 200 through the medium-temperature water preparation circuit Ci2 using the circulation pump 5f, while heating the circulating cooling water Cw through heat exchange with steam in the heat exchanger 11, thereby preparing medium-temperature water Htm (approximately 90°C). Here, the medium-temperature water preparation circuit Ci2 has an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, a branch pipe 6c, and a connection pipe 8a. In the medium-temperature water preparatory circulation path Ci2, the cooling water Cw flows through the connecting pipe 8a, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c in this order.

[0058] <Delivery process> 7, after the medium-temperature water Htm and the high-temperature water Hth are prepared, a carrying-in process is performed. In the carrying-in process, trays Tr on which multiple retort pouches Rp are placed are stacked in multiple layers and carried into the sterilization tank 1 by a user operation.

[0059] <Preheating process> 8, before the heat sterilization of the retort pouch Rp with high-temperature water Hth, the control unit 12 performs control to preheat the sterilization tank 1 and the retort pouch Rp using medium-temperature water Htm supplied from the medium-temperature water tank 4. As a result, the sterilization tank 1 is preheated with the medium-temperature water Htm before the high-temperature water Hth is injected into the sterilization tank 1, thereby suppressing a sudden temperature change Tch1 (see the comparative example in FIG. 4) in the sterilization tank 1.

[0060] Specifically, the control unit 12 performs control to form the medium-temperature water injection path Sp1 by closing the flow path switching valves 6d, 6e, and 7b, and opening the flow path switching valves 5g and 8b. Then, the control unit 12 performs control to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection path Sp1 using the circulation pump 5f (medium-temperature water injection process (see FIG. 3)). Here, the medium-temperature water injection path Sp1 has an upstream pipe 5c, a downstream pipe 5d, and a connecting pipe 8a. In the medium-temperature water injection path Sp1, the medium-temperature water Htm flows in the order of the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

[0061] In this manner, the control unit 12 performs control to supply the medium-temperature water Htm to the sterilization tank 1 through the upstream pipe 5c, the downstream pipe 5d, and the connecting pipe 8a during preheating.

[0062] As shown in Fig. 9, after injecting the medium-temperature water Htm, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby performing control to form the medium-temperature water circulation path Ci3. Then, the control unit 12 performs preheating control by circulating the medium-temperature water Htm to the sterilization tank 1 through the medium-temperature water circulation path Ci3 by the circulation pump 5f without heat exchange in the heat exchanger 11 (medium-temperature water circulation step (see Fig. 3)). Here, the medium-temperature water circulation path Ci3 has a circulation route 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the medium-temperature water circulation path Ci3, the medium-temperature water Htm flows in the order of the discharge pipe 5a and the discharge pipe 5b, the upstream pipe 5c, and the downstream pipe 5d.

[0063] At this time, the control unit 12 performs control to discharge the medium-temperature water Htm supplied from the medium-temperature water tank 4 toward the retort pouch Rp in preheating the sterilization tank 1. Here, in the preheating step, the temperature of the medium-temperature water Htm is lowered to the post-preheating temperature (about 50°C) by applying heat to the sterilization tank 1 and the retort pouch Rp.

[0064] As shown in FIG. 10, the control unit 12 circulates the medium-temperature water Htm for a predetermined time, and then controls the medium-temperature water Htm in the preheated sterilization tank 1 to be recovered and stored in the medium-temperature water tank 4 via the medium-temperature water recovery passage Re1.

[0065] Specifically, the control unit 12 performs control to form the medium-temperature water recovery passage Re1 by closing the flow path switching valves 5g, 6d, 7b, and 8b and opening the flow path switching valve 6e after circulating the medium-temperature water Htm for a predetermined time. Then, the control unit 12 performs recovery control to recover the medium-temperature water Htm to the medium-temperature water tank 4 via the medium-temperature water recovery passage Re1 by the circulation pump 5f (medium-temperature water recovery process (see FIG. 3)). Here, the medium-temperature water recovery passage Re1 has a discharge pipe 5a, a discharge pipe 5b, an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, and a branch pipe 6c. In the medium-temperature water recovery passage Re1, the medium-temperature water Htm flows in the order of the discharge pipe 5a and the discharge pipe 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c.

[0066] Then, the control unit 12 recovers the medium-temperature water Htm in the sterilization tank 1 into the medium-temperature water tank 4 via the medium-temperature water recovery passage Re1, and then performs an object heating step for the retort pouch Rp. At this time, the water level sensor 1c confirms that the medium-temperature water Htm has been discharged from the sterilization tank 1, thereby preventing the temperature of the high-temperature water Hth from being reduced by the medium-temperature water Htm.

[0067] <Object heating process> As shown in FIGS. 11 and 12, the control unit 12 performs control to preheat the retort pouch Rp with the medium-temperature water Htm, and then heat-sterilize the retort pouch Rp using high-temperature water Hth supplied from the high-temperature water bath 3.

[0068] Specifically, as shown in Fig. 11, the control unit 12 performs control to form the hot water injection path Sp2 by closing the flow path switching valves 6d, 6e, and 8b, and opening the flow path switching valves 5g and 7b. Then, the control unit 12 performs control to inject the medium-temperature water Htm in the high-temperature water tank 3 into the sterilization tank 1 via the hot water injection path Sp2 by the circulation pump 5f (high-temperature water injection step (see Fig. 3)). Here, the hot water injection path Sp2 has an upstream pipe 5c, a downstream pipe 5d, a connecting pipe 7a, and a connecting pipe 8a. In the hot water injection path Sp2, the high-temperature water Hth flows in the order of the connecting pipe 7a, the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

[0069] As shown in Fig. 12, after injecting the high-temperature water Hth, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby performing control to form the temperature-raising / heat-sterilizing circulation path Ci4. Then, the control unit 12 performs temperature-raising control to raise the temperature of the high-temperature water Hth to a heat-sterilizing temperature Tst (for example, higher than about 120°C) by heat exchange with steam in the heat exchanger 11, while circulating the high-temperature water Hth to the sterilization tank 1 through the temperature-raising / heat-sterilizing circulation path Ci4 by the circulation pump 5f (temperature-raising step (see Fig. 3)). Here, the temperature-raising / heat-sterilizing circulation path Ci4 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the temperature-raising / heat-sterilization circulation path Ci4, high-temperature water Hth flows through each of the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d in that order. Note that the heat-sterilization temperature Tst being higher than about 120°C is merely an example, and varies depending on the type of object to be heat-sterilized.

[0070] In addition, the control unit 12 heats the high-temperature water Hth up to the heat sterilization temperature Tst, and then circulates the high-temperature water Hth to the sterilization tank 1 through the heating / heat sterilization circulation path Ci4 using the circulation pump 5f, while performing heat sterilization control to maintain the high-temperature water Hth at the heat sterilization temperature Tst by heat exchange with steam in the heat exchanger 11 (heat sterilization process).

[0071] <High-temperature water heat recovery process> As shown in Fig. 13, the control unit 12 performs control for a predetermined time after heat sterilization with high-temperature water Hth to recover and store the high-temperature water Hth in the sterilization tank 1 after heat sterilization in the high-temperature water tank 3 via the hot water recovery passage Re2. The high-temperature hydrothermal recovery process is a process of recovering the high-temperature water Hth in the high-temperature water tank 3 while maintaining the temperature after heat sterilization.

[0072] Specifically, after the heat sterilization by the high-temperature water Hth for a predetermined time, the control unit 12 performs control to form the hot water recovery passage Re2 by closing the flow path switching valves 5g, 6e, 7b, and 8b and opening the flow path switching valve 6d. Then, the control unit 12 performs recovery control to recover the high-temperature water Hth to the high-temperature water tank 3 through the hot water recovery passage Re2 by the circulation pump 5f (high-temperature water heat recovery process (see FIG. 3)). Here, the hot water recovery passage Re2 has the discharge pipe 5a, the discharge pipe 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6b. In the hot water recovery passage Re2, the high-temperature water Hth flows in the order of the discharge pipe 5a and the discharge pipe 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6b.

[0073] Then, the control unit 12 recovers the high-temperature water Hth discharged from the sterilization tank 1 into the high-temperature water tank 3 via the hot water recovery passage Re2, and then performs a medium-temperature water heat recovery process for the sterilization tank 1 and the retort pouch Rp. That is, the control unit 12 controls the medium-temperature water heat recovery process in a state in which the high-temperature water Hth after thermal sterilization is discharged from the sterilization tank 1. At this time, the water level sensor 1c confirms that the high-temperature water Hth has been discharged from the sterilization tank 1, thereby suppressing the temperature of the medium-temperature water Htm from increasing due to the high-temperature water Hth.

[0074] <Medium-temperature water heat recovery process> 14 to 16, before cooling the retort pouch Rp with cooling water Cw, the control unit 12 performs a medium-temperature water heat recovery step of recovering heat from the sterilization tank 1 and the retort pouch Rp using medium-temperature water Htm supplied from the medium-temperature water tank 4. As a result, heat from the sterilization tank 1 is recovered by the medium-temperature water Htm before cooling water Cw is injected into the sterilization tank 1, thereby suppressing a sudden temperature change Tch2 in the sterilization tank 1 (see the comparative example in FIG. 4).

[0075] Specifically, as shown in Fig. 14, the control unit 12 performs control to form the medium-temperature water injection passage Sp3 by closing the flow path switching valves 6d, 7b, and 6e and opening the flow path switching valves 5g and 8b. Then, the control unit 12 performs control to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection passage Sp3 by the circulation pump 5f (medium-temperature water injection step (see Fig. 3)). Here, the medium-temperature water injection passage Sp3 has an upstream pipe 5c, a downstream pipe 5d, and a connecting pipe 8a. In the medium-temperature water injection passage Sp3, the medium-temperature water Htm flows in the order of the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

[0076] As shown in FIG. 15, after injecting the medium-temperature water Htm, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby performing control to form the heat recovery circulation path Ci5. Then, the control unit 12 performs medium-temperature water heat recovery control by circulating the medium-temperature water Htm to the sterilization tank 1 through the heat recovery circulation path Ci5 by the circulation pump 5f without heat exchange in the heat exchanger 11 (medium-temperature water circulation step (see FIG. 3)). Here, the heat recovery circulation path Ci5 has a circulation route 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the heat recovery circulation path Ci5, the medium-temperature water Htm flows in the order of the discharge pipe 5a and the discharge pipe 5b, the upstream pipe 5c, and the downstream pipe 5d.

[0077] At this time, the control unit 12 performs control to discharge the medium-temperature water Htm supplied from the medium-temperature water tank 4 toward the retort pouch Rp in the heat recovery of the sterilization tank 1. Here, in the medium-temperature water circulation process, the temperature of the medium-temperature water Htm rises to the post-heat recovery temperature (about 90°C) by removing heat from each of the sterilization tank 1 and the retort pouch Rp.

[0078] As shown in FIG. 16, the control unit 12 circulates the medium-temperature water Htm for a predetermined time, and then controls the medium-temperature water Htm in the sterilization tank 1 after heat recovery to be recovered and stored in the medium-temperature water tank 4 via the medium-temperature water recovery path Re3.

[0079] Specifically, the control unit 12 performs control to form the medium-temperature water recovery passage Re3 by closing the flow path switching valves 5g, 6d, 7b, and 8b and opening the flow path switching valve 6e after circulating the medium-temperature water Htm for a predetermined time. Then, the control unit 12 performs recovery control to recover the medium-temperature water Htm to the medium-temperature water tank 4 via the medium-temperature water recovery passage Re3 by the circulation pump 5f (medium-temperature water recovery process (see FIG. 3)). Here, the medium-temperature water recovery passage Re3 has a discharge pipe 5a, a discharge pipe 5b, an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, and a branch pipe 6c. In the medium-temperature water recovery passage Re3, the medium-temperature water Htm flows in the order of the discharge pipe 5a and the discharge pipe 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c.

[0080] In this way, the control unit 12 performs a medium-temperature water heat recovery step of recovering heat from the sterilization tank 1 after thermal sterilization using the medium-temperature water Htm supplied from the medium-temperature water tank 4 before the step of cooling the object in the retort pouch Rp with the cooling water Cw, and also controls the medium-temperature water Htm used in the medium-temperature water heat recovery step to be stored in the medium-temperature water tank 4. That is, the control unit 12 controls the medium-temperature water Htm in the sterilization tank 1 after heat recovery to be recovered and stored in the medium-temperature water tank 4 via the discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, downstream pipe 5d, common pipe 6a, and branch pipe 6c.

[0081] Then, the control unit 12 recovers the medium-temperature water Htm in the sterilization tank 1 into the medium-temperature water tank 4 via the medium-temperature water recovery passage Re3, and then performs a cooling process for the retort pouch Rp. At this time, the water level sensor 1c confirms that the medium-temperature water Htm has been discharged from the sterilization tank 1, thereby preventing the temperature of the cooling water Cw from increasing due to the medium-temperature water Htm.

[0082] <Object cooling process> As shown in Figures 17 to 19, after heat recovery of the retort pouch Rp by the medium-temperature water Htm, the control unit 12 performs a cooling process to cool the retort pouch Rp and the sterilization tank 1 using cooling water Cw supplied from the cooling water source 200 (see Figure 1).

[0083] Specifically, as shown in Fig. 17, the control unit 12 performs control to form the cooling water injection passage Sp4 by closing the flow path switching valves 6d, 6e, 7b, and 8b and opening the flow path switching valve 5g. Then, the control unit 12 performs control to inject the cooling water Cw supplied from the cooling water source 200 by the circulation pump 5f through the cooling water injection passage Sp4 into the sterilization tank 1 (cooling water injection process (see Fig. 3)). Here, the cooling water injection passage Sp4 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the cooling water injection passage Sp4, the cooling water Cw flows in the order of the upstream pipe 5c, the downstream pipe 5d, the discharge pipe 5a, and the discharge pipe 5b.

[0084] As shown in Fig. 18, after injecting the cooling water Cw, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby forming the cooling circulation path Ci6. The control unit 12 then performs cooling control to cool the cooling water Cw, which has been heated by removing heat from the retort pouch Rp and the sterilization tank 1 through heat exchange with the cooling water in the heat exchanger 11, while circulating the cooling water Cw through the cooling circulation path Ci6 by the circulation pump 5f (cooling step (see Fig. 3)). Here, the cooling circulation path Ci6 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the cooling circulation path Ci6, the cooling water Cw flows through each of the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d in this order.

[0085] 19, the control unit 12 performs control for a predetermined time to recover the cooling water Cw in the sterilization tank 1 after cooling with the cooling water Cw through the cooling water recovery line Re4 using the circulation pump 5f (cooling water recovery step). Here, the cooling water recovery line Re4 has a discharge pipe 5a, a discharge pipe 5b, and an upstream pipe 5c. In the cooling water recovery line Re4, the cooling water Cw flows through each of the discharge pipes 5a and 5b, and then through the upstream pipe 5c, in that order.

[0086] <Export process> In the carrying-out step, as shown in FIG. 20, the cooled retort pouches Rp are carried out from the sterilization tank 1 by the user.

[0087] Then, the next heat sterilization control is performed on the multiple retort pouches Rp. At this time, the control unit 12 performs a preheating process of preheating the sterilization tank 1 using the medium-temperature water Htm heated during the medium-temperature water heat recovery process (medium-temperature water heat recovery control) and stored in the medium-temperature water tank 4, before heating the retort pouches Rp with the high-temperature water Hth. As a result, in the heat sterilization control of this embodiment, the heat taken from the retort pouches Rp and the sterilization tank 1, etc. during the medium-temperature water heat recovery process is utilized, so that the occurrence of heat loss is suppressed. In addition, since only a slight re-heating (for example, about 1 to 2°C) is required during the advance preparation of the medium-temperature water Htm shown in FIG. 6, the amount of heat required for heating the medium-temperature water Htm and the time required for heating the medium-temperature water Htm are suppressed after the first heat sterilization control.

[0088] Such heat sterilization control is performed multiple times a day. Then, the medium-temperature water Htm stored in the medium-temperature water tank 4 is reused and then discharged from the medium-temperature water tank 4. Then, control is performed to store new medium-temperature water Htm in the medium-temperature water tank 4 (see FIG. 6). The timing for replacing such medium-temperature water Htm is once a day or once every few days, and is appropriately set by the user. This suppresses an increase in water usage caused by using the medium-temperature water Htm, compared to the case where medium-temperature water Htm is prepared for each heating control.

[0089] (Comparison between heat sterilization control of a comparative example and heat sterilization control of this embodiment) Fig. 21 shows a graph in which the graph of heat sterilization control of the comparative example (corresponding to the conventional example) shown in Fig. 4 is superimposed on the graph of heat sterilization control of this embodiment shown in Fig. 3. Here, the graph of heat sterilization control of the comparative example is shown by a thick two-dot chain line. Also, the graph of heat sterilization control of this embodiment is shown by a thick solid line.

[0090] Comparing the heat sterilization control of the comparative example with the heat sterilization control of the present embodiment, the operation time of the heat sterilization control of the embodiment increases by time Tlag because the preheating process and the medium temperature water heat recovery process are added.

[0091] However, the time Ui of the temperature rise process of the object heating process in the heat sterilization control of this embodiment is shorter than the time Ue of the temperature rise process of the object heating process in the heat sterilization control of the comparative example. This is because, in the heat sterilization control of this embodiment, the initial temperature of the object heating process is higher than the initial temperature of the object heating process in the heat sterilization control of the comparative example due to the preheating process. Furthermore, the time Di of the object cooling process in the heat sterilization control of this embodiment is shorter than the time De of the object cooling process in the heat sterilization control of the comparative example. This is because, in the heat sterilization control of this embodiment, the initial temperature of the object cooling process is lower than the initial temperature of the object cooling process in the heat sterilization control of the comparative example due to the medium-temperature water heat recovery process.

[0092] Furthermore, by making the temperature raising step time Ui shorter than the temperature raising step time Ue, the amount of steam required to raise the temperature of the high-temperature water Hth is reduced. Furthermore, in advance preparation of the medium-temperature water Htm, the medium-temperature water Htm is heated with steam, but due to reuse of the medium-temperature water Htm and the reduction in the amount of steam required to raise the temperature of the high-temperature water Hth, when heat sterilization control is performed multiple times, the thermal energy required for heat sterilization control is reduced compared to the case where the heat sterilization control of the comparative example is performed multiple times.

[0093] In addition, in the heat sterilization control of this embodiment, since the medium temperature water Htm is injected into the sterilization tank 1 after the carry-in step, the temperature change Ti1 of the sterilization tank 1 after the carry-in step is smaller by the temperature difference Td1 than the temperature change Te1 of the sterilization tank 1 after the carry-in step in the comparative example. Furthermore, in the heat sterilization control, since the medium temperature water Htm is injected into the sterilization tank 1 after the high temperature hydrothermal recovery step, the temperature change Ti2 of the sterilization tank 1 after the high temperature hydrothermal recovery step is smaller by the temperature difference Td2 than the temperature change Te2 of the sterilization tank 1 after the carry-in step in the comparative example. This suppresses abrupt temperature changes in the sterilization tank 1, thereby suppressing expansion and contraction of the sterilization tank 1.

[0094] (heat sterilization method) A heat sterilization method performed in the above-mentioned heat sterilization apparatus 100 will be described with reference to Figures 7, 9, 12, 15, 18, 20 and 22. The heat sterilization method is a method executed by the control unit 12 based on a heat sterilization program.

[0095] Here, high temperature water Hth and medium temperature water Htm are prepared before the preheating process of step S1 shown in Fig. 22. Here, in the following explanation, it is assumed that the medium temperature water Htm is heated during the above-mentioned medium temperature water heat recovery process (medium temperature water heat recovery control) and stored in the medium temperature water tank 4. Then, a carrying-in process is performed in which trays Tr on which multiple retort pouches Rp are placed are carried into the sterilization tank 1 by a user in a state where they are stacked in multiple layers (see Fig. 7).

[0096] In step S1 shown in Fig. 22, a preheating step is performed after the carrying-in step. The preheating step is a step in which the sterilization tank 1 is preheated using medium-temperature water Htm heated during heat recovery from the sterilization tank 1 before high-temperature water Hth for heat-sterilizing the retort pouch Rp is supplied to the sterilization tank 1 (see Fig. 9).

[0097] In step S2, an object heating step is performed. The object heating step is a step of supplying high-temperature water Hth to a sterilization tank 1 for performing heat sterilization with high-temperature water Hth to heat sterilize the retort pouch Rp in the sterilization tank 1 (see FIG. 12).

[0098] In step S3, a high-temperature hydrothermal recovery process is performed. The high-temperature hydrothermal recovery process is a process in which, after heat sterilization using high-temperature water Hth, the high-temperature water Hth in the sterilization tank 1 after heat sterilization is recovered and stored in the high-temperature water tank 3 via the hot water recovery passage Re2 (see FIG. 13).

[0099] In step S4, a medium-temperature water heat recovery process is performed. The medium-temperature water heat recovery process is a process for recovering heat from the sterilization tank 1 after thermal sterilization, using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth, before cooling the retort pouch Rp with the cooling water Cw (see FIG. 15).

[0100] In step S5, an object cooling step is performed. The object cooling step is a step of cooling the heat-sterilized retort pouch Rp with cooling water Cw after heat recovery in the sterilization tank 1 (see FIG. 18). Then, after step S5, the heat sterilization method ends.

[0101] Here, after the thermal sterilization method is completed, a carry-out step is performed in which the cooled retort pouch Rp is carried out from the sterilization tank 1 by a user (see FIG. 20).

[0102] (retort pouch) The retort pouch Rp produced by such a heat sterilization bath method is subjected to heat sterilization treatment by a heat sterilization device 100.

[0103] Specifically, the retort pouch Rp (object to be sterilized) is subjected to heat sterilization treatment by a heat sterilization device 100 having a storage space 1d for storing the retort pouch Rp (object to be sterilized) therein to be heat sterilized with high-temperature water Hth (high-temperature fluid), a sterilization tank 1 to which high-temperature water Hth (high-temperature fluid) for heat sterilizing the retort pouch Rp (object to be sterilized) and cooling water Cw for cooling the retort pouch Rp (object to be sterilized) heat sterilized with the high-temperature water Hth (high-temperature fluid) are supplied, and a control unit 12 for performing medium-temperature water heat recovery control for recovering heat from the sterilization tank 1 after heat sterilization using medium-temperature water Htm that is generated separately from the high-temperature water Hth (high-temperature fluid) and has a temperature higher than the cooling water Cw and lower than the temperature of the high-temperature water Hth (high-temperature fluid) before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw.

[0104] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0105] In this embodiment, as described above, the heat sterilization apparatus 100 includes a control unit 12 that performs a medium-temperature water heat recovery process (medium-temperature water heat recovery control) to recover heat from the sterilization tank 1 after the object heating process (heat sterilization control) using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. As a result, by performing heat recovery from the sterilization tank 1 after heat sterilization using the medium-temperature water Htm generated separately from the high-temperature water Hth, it is possible to prevent the temperature of the high-temperature water Hth from decreasing, and therefore it is possible to suppress an increase in the time required to raise the temperature of the high-temperature water Hth to the heat sterilization temperature Tst during the next heat sterilization after the heat recovery. Furthermore, since the sterilization tank 1 after the object heating step (heat sterilization control) can be cooled with medium-temperature water Htm having a higher temperature than the cooling water Cw before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, a sudden change in temperature (sudden temperature drop) in the sterilization tank 1 after the object heating step (heat sterilization control) can be suppressed. As a result, the degree of expansion and contraction of the sterilization tank 1 can be reduced, and unlike the case where large expansion and contraction are repeated, an increase in metal fatigue due to thermal stress can be suppressed, and a decrease in the durability of the sterilization tank 1 (shortening of its lifespan) can be suppressed.

[0106] Furthermore, in this embodiment, as described above, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, the control unit 12 performs a medium-temperature water heat recovery process (medium-temperature water heat recovery control) to recover heat from the sterilization tank 1 after the object heating process (heat sterilization control) using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth. This allows the heat loss of the heat given to the retort pouch Rp and the sterilization tank 1 during the object heating process (heat sterilization control) to be suppressed by recovering the heat from the sterilization tank 1 after the object heating process (heat sterilization control) using the medium-temperature water Htm in the medium-temperature water heat recovery process (medium-temperature water heat recovery control).

[0107] Furthermore, in this embodiment, as described above, the control unit 12 performs the medium temperature water heat recovery step (medium temperature water heat recovery control) in a state in which the high temperature water Hth after thermal sterilization is discharged from the sterilization tank 1. As a result, heat recovery using the high temperature water Hth is performed simply by discharging the high temperature water Hth, and therefore a dedicated heat exchanger and water supply tank for heat recovery using the high temperature water Hth are not required, and therefore it is possible to suppress an increase in size of the device due to heat recovery using the high temperature water Hth.

[0108] In this embodiment, as described above, the heat sterilization device 100 includes the medium-temperature water tank 4 in which the medium-temperature water Htm is stored. The control unit 12 is configured to perform a medium-temperature water heat recovery step (medium-temperature water heat recovery control) of recovering heat from the sterilization tank 1 after heat sterilization using the medium-temperature water Htm supplied from the medium-temperature water tank 4 before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, and to store the medium-temperature water Htm used in the medium-temperature water heat recovery step (medium-temperature water heat recovery control) in the medium-temperature water tank 4. Thus, by storing the medium-temperature water Htm in the medium-temperature water tank 4, the medium-temperature water Htm can be easily supplied to the sterilization tank 1 after heat sterilization during heat recovery, and by storing the medium-temperature water Htm used for heat recovery in the medium-temperature water tank 4 without discharging it, the recovered heat can be easily reused.

[0109] In this embodiment, as described above, the control unit 12 performs a preheating step (preheating control) of preheating the sterilization tank 1 using the medium-temperature water Htm heated during the medium-temperature water heat recovery step (medium-temperature water heat recovery control) and stored in the medium-temperature water tank 4 before heating the retort pouch Rp (object to be sterilized) with the high-temperature water Hth. As a result, the initial temperature of the sterilization tank 1 at the start of the object heating step (heat sterilization control) can be increased by preheating the sterilization tank 1 using the heated medium-temperature water Htm used for heat recovery, so that the amount of heat given to the high-temperature water Hth during the temperature increase to increase the temperature of the high-temperature water Hth to the temperature at which the object heating step (heat sterilization control) is performed can be reduced compared to the case where preheating is not performed. That is, by using the medium-temperature water Htm, the heat recovered can be effectively used for preheating. As a result, when preheating is performed, the increase in thermal energy required in the heat sterilization device 100 can be reduced, and the amount of (high-temperature) steam used to increase the temperature of the high-temperature water Hth can be reduced accordingly.

[0110] In this embodiment, as described above, the heat sterilization device 100 includes the circulation path 5, the common pipe 6a, the branch pipe 6c, and the connection pipe 8a (first connection path) that connect the sterilization tank 1 and the medium-temperature water tank 4 to each other. The control unit 12 controls the recovery and storage of the medium-temperature water Htm in the sterilization tank 1 after heat recovery in the medium-temperature water tank 4 via the discharge pipe 5a, the discharge pipe 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c (first connection path), and controls the supply of the medium-temperature water Htm to the sterilization tank 1 via the upstream pipe 5c, the downstream pipe 5d, and the connection pipe 8a (first connection path) during preheating. This makes it possible to easily store the medium-temperature water Htm after heat recovery in the medium-temperature water tank 4, and to supply the medium-temperature water Htm during preheating from the medium-temperature water tank 4 to the sterilization tank 1, using the common pipe 6a and the branch pipe 6c (first connection path).

[0111] In this embodiment, as described above, the control unit 12 controls the medium-temperature water Htm supplied from the medium-temperature water tank 4 to be discharged toward the retort pouch Rp (object to be sterilized) during preheating of the sterilization tank 1 and heat recovery of the sterilization tank 1. As a result, when the low-temperature sterilization tank 1 is preheated, the discharged medium-temperature water Htm hits the retort pouch Rp (object to be sterilized) to lower the temperature of the medium-temperature water Htm, and the medium-temperature water Htm with the lowered temperature can be applied to the sterilization tank 1, so that a sudden change in temperature of the sterilization tank 1 can be suppressed. Also, when the heat recovery of the sterilization tank 1 is performed, the discharged medium-temperature water Htm hits the retort pouch Rp (object to be sterilized) to raise the temperature of the medium-temperature water Htm, and the high-temperature sterilization tank 1 during heat recovery can be applied with the medium-temperature water Htm with the increased temperature, so that a sudden change in temperature of the sterilization tank 1 can be suppressed. As a result, in each of preheating the sterilization tank 1 and heat recovery of the sterilization tank 1, the decrease in durability of the sterilization tank 1 caused by an increase in thermal stress due to a sudden temperature change can be further suppressed.

[0112] Furthermore, in this embodiment, as described above, the heat sterilization apparatus 100 includes a high-temperature water tank 3 that collects and stores high-temperature water Hth, which is high-temperature water Hth stored in the sterilization tank 1 after the object heating step (heat sterilization control). The heat sterilization apparatus 100 includes a common pipe line 6a and a branch pipe line 6b (second connection path) that connect the sterilization tank 1 and the high-temperature water tank 3 to each other. The control unit 12 collects the high-temperature water Hth discharged from the sterilization tank 1 after the object heating step (heat sterilization control) of the retort pouch Rp (sterilization object) is completed into the high-temperature water tank 3 via the common pipe line 6a and the branch pipe line 6b (second connection path), and then performs a medium-temperature water heat recovery step (medium-temperature water heat recovery control) of the sterilization tank 1. As a result, by recovering the high-temperature water Hth in the sterilization tank 1 through a dedicated common pipeline 6a and a branch pipeline 6b (second connection path) that connect the sterilization tank 1 and the high-temperature water tank 3 to each other, it is possible to prevent the heat of the high-temperature water Hth from being lost after the object heating process (heat sterilization control), and therefore it is possible to suppress a decrease in the temperature of the high-temperature water Hth recovered in the high-temperature water tank 3.

[0113] Furthermore, in this embodiment, as described above, the heat sterilization apparatus 100 includes a circulation path 5 including a circulation pump 5f that discharges each of the cooling water Cw, high temperature water Hth, and medium temperature water Htm discharged from the sterilization tank 1 and circulates them to the sterilization tank 1. The control unit 12 performs a medium temperature water heat recovery step (medium temperature water heat recovery control) by circulating the medium temperature water Htm to the sterilization tank 1 via the circulation path 5 using the circulation pump 5f. This allows the circulation path 5 used in each of the object heating step (heat sterilization control) and the object cooling step (cooling control) to be commonly used in the medium temperature water heat recovery step (medium temperature water heat recovery control), thereby making it possible to suppress the structure from becoming complicated and large due to an increase in the number of paths in the heat sterilization apparatus 100.

[0114] Furthermore, in this embodiment, as described above, the retort pouch Rp (object to be sterilized) is heat sterilized by a heat sterilization device 100 having an accommodation space 1d for accommodating the retort pouch Rp (object to be sterilized) to be heat sterilized with high-temperature water Hth, a sterilization tank 1 to which high-temperature water Hth for performing an object heating step (heat sterilization control) on the object to be sterilized and cooling water Cw for cooling the retort pouch Rp (object to be sterilized) that has been subjected to the object heating step (heat sterilization control) with the high-temperature water Hth is supplied, and a control unit 12 for performing a medium-temperature water heat recovery step (medium-temperature water heat recovery control) for recovering heat from the sterilization tank 1 after the object heating step (heat sterilization control) using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than the cooling water Cw and lower than the temperature of the high-temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. As a result, by performing heat recovery in the sterilization tank 1 after heat sterilization using the medium temperature water Htm generated separately from the high temperature water Hth, it is possible to prevent the temperature of the high temperature water Hth from decreasing, and therefore it is possible to prevent the time required to raise the temperature of the high temperature water Hth to the heat sterilization temperature Tst during the next heat sterilization after heat recovery from being lengthened, and it is possible to provide a retort pouch Rp (object to be sterilized) that has been heat sterilized by the heat sterilization apparatus 100 that can prevent a decrease in durability of the sterilization tank 1 due to an increase in thermal stress caused by a sudden temperature change.

[0115] In addition, in this embodiment, as described above, the heat sterilization method includes step S4 of recovering heat from the sterilization tank 1 after the object heating step (heat sterilization control) using intermediate temperature water Htm generated separately from the high temperature water Hth, which has a temperature higher than that of the cooling water Cw and lower than that of the high temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. This makes it possible to prevent the temperature of the high temperature water Hth from decreasing by recovering heat from the sterilization tank 1 after heat sterilization using intermediate temperature water Htm generated separately from the high temperature water Hth, so that it is possible to provide a heat sterilization method that can prevent the time required to heat the high temperature water Hth to the heat sterilization temperature Tst from becoming long during the next heat sterilization after heat recovery and that can prevent a decrease in the durability of the sterilization tank 1 caused by an increase in thermal stress due to a sudden temperature change.

[0116] In addition, in this embodiment, as described above, the heat sterilization method includes a step S1 of preheating the sterilization tank 1 using the medium-temperature water Htm heated during heat recovery of the sterilization tank 1 before supplying the high-temperature water Hth for performing the object heating step (heat sterilization control) of the retort pouch Rp (sterilization object) to the sterilization tank 1. By preheating the sterilization tank 1, the initial temperature of the sterilization tank 1 at the start of the object heating step (heat sterilization control) can be increased, so that the amount of heat given to the high-temperature water Hth during the temperature increase to increase the temperature of the high-temperature water Hth to the temperature for performing the object heating step (heat sterilization control) can be reduced compared to the case where preheating is not performed. In addition, by using the medium-temperature water Htm after the medium-temperature water heat recovery step (medium-temperature water heat recovery control) to preheat the sterilization tank 1, the heat of the sterilization tank 1 and the retort pouch Rp (sterilization object) after the object heating step (heat sterilization control) can be used to increase the temperature of the medium-temperature water Htm to the preheating temperature. As a result, in preheating the sterilization tank 1 with the medium-temperature water Htm after the medium-temperature water heat recovery process (medium-temperature water heat recovery control), the thermal energy required in the heat sterilization apparatus 100 due to the preheating can be reduced, and the amount of (high-temperature) steam used to raise the temperature of the high-temperature water Hth can be reduced accordingly.

[0117] Furthermore, in this embodiment, as described above, in the preheating step, the control unit 12 closes the flow path switching valves 6d, 6e, and 7b and opens the flow path switching valves 5g and 8b to form the medium-temperature water injection path Sp1, and then controls the circulation pump 5f to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection path Sp1. This makes it possible to inject the medium-temperature water Htm from the medium-temperature water tank 4 into the sterilization tank 1 without using a pump other than the circulation pump 5f.

[0118] Furthermore, in this embodiment, as described above, in the preheating step, the control unit 12 closes the flow path switching valves 5g, 6d, 7b, and 8b and opens the flow path switching valve 6e to form the medium temperature water recovery passage Re1, and then performs recovery control to recover the medium temperature water Htm into the medium temperature water tank 4 via the medium temperature water recovery passage Re1 using the circulation pump 5f. This makes it possible to recover the medium temperature water Htm from the sterilization tank 1 to the medium temperature water tank 4 without using a pump other than the circulation pump 5f.

[0119] Furthermore, in this embodiment, as described above, in the medium-temperature water heat recovery step, the control unit 12 closes the flow path switching valves 6d, 7b, and 6e and opens the flow path switching valves 5g and 8b to form the medium-temperature water injection path Sp3, and then controls the circulation pump 5f to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection path Sp3. This makes it possible to inject the medium-temperature water Htm from the medium-temperature water tank 4 into the sterilization tank 1 without using a pump other than the circulation pump 5f.

[0120] Furthermore, in this embodiment, as described above, in the medium temperature water heat recovery step, the control unit 12 closes the flow path switching valves 5g, 6d, 7b, and 8b and opens the flow path switching valve 6e to form the medium temperature water recovery passage Re3, and then performs recovery control to recover the medium temperature water Htm through the medium temperature water recovery passage Re3 into the medium temperature water tank 4 using the circulation pump 5f. This makes it possible to recover the medium temperature water Htm from the sterilization tank 1 to the medium temperature water tank 4 without using a pump other than the circulation pump 5f.

[0121] In this embodiment, the supply path 6 is a pipe branching off from the circulation path 5 and supplying high-temperature water Hth to the high-temperature water tank 3. The supply path 6 is a pipe branching off from the circulation path 5 and supplying medium-temperature water Htm to the medium-temperature water tank 4. The supply path 6 includes a common pipe 6a. The common pipe 6a is connected to the circulation path 5 and is a common pipe for the high-temperature water tank 3 and the medium-temperature water tank 4. As a result, when the sterilization tank 1 is preheated with the medium-temperature water Htm, the medium-temperature water Htm flows through the common pipe 6a, so that not only the sterilization tank 1 but also the common pipe 6a is preheated by the medium-temperature water Htm. Therefore, compared to a case where the piping connecting the sterilization tank 1 to the high-temperature water tank 3 and the medium-temperature water tank 4 is not shared, the common pipe 6a is also preheated when the high-temperature water Hth is supplied to the sterilization tank 1 after the sterilization tank 1 is preheated, so that a sudden temperature rise can be suppressed not only in the sterilization tank 1 but also in the common pipe 6a. As a result, the risk of cracks occurring due to stress caused by a sudden temperature rise can be reduced not only in the sterilization tank 1 but also in the common pipe 6a. In addition, when recovering heat from the sterilization tank 1 using the medium temperature water Htm, the medium temperature water Htm flows through the common pipe 6a heated by the high temperature water Hth when recovering the high temperature water Hth in the sterilization tank 1 to the high temperature water tank 3, so that not only the heat of the sterilization tank 1 but also the heat of the common pipe 6a heated by the high temperature water Hth is recovered by the medium temperature water Htm. As a result, the heat of the common pipe 6a heated by the high temperature water Hth can also be recovered, so the temperature of the medium temperature water Htm used to preheat the sterilization tank 1 next time can be made higher compared to when the common pipe 6a is not used.

[0122] In this embodiment, as described above, the medium-temperature water tank 4 is a tank that collects and stores the medium-temperature water Htm after preheating and heat recovery stored in the sterilization tank 1. This allows the medium-temperature water Htm to be preheated to be stored by collecting the medium-temperature water Htm after heat recovery, and allows the medium-temperature water Htm to be stored to be heat recovered by collecting the medium-temperature water Htm after preheating. This allows the supply source of the medium-temperature water Htm to the sterilization tank 1 and the destination of the medium-temperature water Htm recovered from the sterilization tank 1 to be the single medium-temperature water tank 4, making it possible to realize a heat sterilization device 100 that performs heat recovery and preheating with a simple configuration.

[0123] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

[0124] For example, in the above embodiment, the heat sterilization apparatus 100 is an example of a spray type apparatus equipped with the spray nozzle 2, but the present invention is not limited to this. In the present invention, the heat sterilization apparatus may be a hot water storage type apparatus that performs preheating and heat recovery using medium temperature water, or a steam type apparatus that uses steam as a high-temperature fluid.

[0125] For example, in a hot water storage type heat sterilization device 500 of a first modified example as shown in Fig. 23, the following heat sterilization control is performed. That is, after the retort pouch Rp (sterilization object) is heat sterilized by high-temperature water Hth (high-temperature fluid) in the object heating step, the control unit 512 recovers the high-temperature water Hth (high-temperature fluid) discharged from the sterilization tank 1 into the high-temperature water tank 503, and then performs medium-temperature water heat recovery control to recover the heat of the sterilization tank 1 after heat sterilization, using medium-temperature water Htm generated separately from the high-temperature water Hth (high-temperature fluid).

[0126] Here, in the hot water storage type heat sterilization device 500, high temperature water Hth (high temperature fluid) is not used for heat sterilization, but after recovering high temperature water Hth in the high temperature water tank 503, the medium temperature water Htm in the medium temperature water tank 4 is circulated to the sterilization tank 1, thereby making it possible to recover heat from the sterilization tank 1 after heat sterilization, and therefore it is possible to prevent the temperature of the high temperature water Hth from decreasing.

[0127] Also, for example, in a steam-type heat sterilization device 600 of a second modified example as shown in Fig. 24, the following heat sterilization control is performed. That is, after the control unit 612 heats and sterilizes the retort pouch Rp (sterilization object) with high-temperature steam Vah (high-temperature fluid) in the object heating step, it performs medium-temperature water heat recovery control to recover heat from the sterilization tank 1 after heat sterilization, using medium-temperature water Htm generated separately from the high-temperature steam Vah (high-temperature fluid).

[0128] Here, the steam-type heat sterilization apparatus 600 uses steam Vah (high-temperature fluid) for heat sterilization instead of high-temperature water, so heat recovery using high-temperature water cannot be performed. However, with the above-mentioned configuration of the second modified example of this embodiment, by performing medium-temperature water heat recovery control, the steam-type heat sterilization apparatus 600 can also recover heat from the sterilization tank 1 after heat sterilization.

[0129] In the above embodiment, the heat sterilization apparatus 100 is provided with both the high temperature water tank 3 and the medium temperature water tank 4, but the present invention is not limited to this. In the present invention, the heat sterilization apparatus only needs to include the medium temperature water tank, and does not necessarily need to include the hot water tank.

[0130] In the above embodiment, the heat sterilization device 100 is an apparatus for heat sterilizing the retort pouch Rp containing food by using high-temperature water Hth, but the present invention is not limited to this. In the present invention, the heat sterilization device may be an apparatus for heat sterilizing other products such as canned goods.

[0131] In the above embodiment, the control unit 12 is configured to directly use the medium-temperature water Htm supplied from the medium-temperature water tank 4 to preheat the sterilization tank 1 and the retort pouch Rp and to recover heat, but the present invention is not limited to this. That is, the heat sterilization device may have a modified configuration in which medium-temperature water is indirectly used as follows.

[0132] Specifically, as in a third modified example shown in Fig. 25, the heat sterilization apparatus 700 includes a heat transfer fluid supply unit 713 that supplies a heat transfer fluid Htf heated by medium-temperature water Htm. The heat sterilization apparatus 700 includes a heat exchanger 714 that exchanges heat between the medium-temperature water Htm stored in the medium-temperature water tank 704 and the heat transfer fluid Htf supplied from the heat transfer fluid supply unit 713. In preheating the sterilization tank 1, the control unit 12 controls the supply of the heat transfer fluid Htf whose temperature has been increased by heat exchange with the medium-temperature water Htm in the heat exchanger 714 to the sterilization tank 1, and in heat recovery of the sterilization tank 1, controls the supply of the heat transfer fluid Htf whose temperature has been reduced by heat exchange with the medium-temperature water Htm in the heat exchanger 714 to the sterilization tank 1.

[0133] As a result, in preheating the sterilization tank 1, the heat transfer fluid Htf and the medium-temperature water Htm are heated by heat exchange in the heat exchanger 714, and the heat transfer fluid Htf can be supplied to the sterilization tank 1 while gradually increasing the temperature of the heat transfer fluid Htf. Therefore, the temperature of the sterilization tank 1 can be gradually increased to the preheating temperature by the heat transfer fluid Htf while suppressing the temperature difference with the sterilization tank 1. As a result, a sudden change in temperature of the sterilization tank 1 can be further suppressed. In addition, by recovering heat by heat exchange between the heat transfer fluid Htf and the medium-temperature water Htm in the heat exchanger 714, the heat transfer fluid Htf can be supplied to the sterilization tank 1 while gradually decreasing the temperature of the heat transfer fluid Htf. Therefore, the temperature difference with the sterilization tank 1 can be suppressed, and the sterilization tank 1 can be gradually lowered to the post-heat recovery temperature (pre-cooling temperature) by the heat transfer fluid Htf. As a result, a sudden change in temperature of the sterilization tank 1 can be further suppressed.

[0134] 25, a medium-temperature water tank 704 is connected to a heat exchanger 714. That is, the medium-temperature water tank 704 includes an inlet pipe 704c, a supply pipe 704d, a flow path switching valve 704e, and a flow path switching valve 704f.

[0135] Furthermore, in the above embodiment, an example has been shown in which the control unit 12 performs both control of recovering and storing the medium-temperature water Htm in the sterilization tank 1 after preheating in the medium-temperature water tank 4, and control of recovering and storing the medium-temperature water Htm in the sterilization tank 1 after heat recovery in the medium-temperature water tank 4, but the present invention is not limited to this. In the present invention, it is sufficient that the control unit performs at least one of control of recovering and storing the medium-temperature water in the sterilization tank after preheating in the medium-temperature water tank, and control of recovering and storing the medium-temperature water in the sterilization tank after heat recovery in the medium-temperature water tank.

[0136] In the above embodiment, for convenience of explanation, the control process of the control unit 12 is described using a flow-driven flowchart in which the process is performed in order according to the process flow, but the present invention is not limited to this. In the present invention, the control process of the control unit may be performed by an event-driven process in which the process is performed on an event-by-event basis. In this case, the control process may be performed completely event-driven, or may be performed in a combination of event-driven and flow-driven. [Explanation of symbols]

[0137] 1 Sterilization tank 1d Containment space 3, 503 High temperature water tank 4. 704 Medium temperature water tank 5 Circulation route (first connection route, second connection route) 5a Discharge pipe (first connection path, second connection path) 5b Discharge pipe (first connection path, second connection path) 5c Upstream pipeline (first connection path, second connection path) 5d Downstream pipe 5d (first connection path, second connection path) 5f Circulation Pump 6a Common pipe (first connection path, second connection path) 6b Branch pipeline (second connection route) 6c Branch pipeline (first connection route) 11 Heat exchanger 12, 612 Control section 100, 500, 600, 700 Heat sterilizer 713 Heat transfer fluid supply section 714 Heat exchanger CW cooling water Htf Heat Transfer Fluid Hth high temperature water Htm medium temperature water Rp retort pouch (for sterilization)

Claims

1. A sterilization tank having an accommodation space for accommodating an object to be sterilized by heat sterilization using a high-temperature fluid, and supplied with the high-temperature fluid for heat sterilizing the object and cooling water for cooling the object that has been heat sterilized by the high-temperature fluid; A medium temperature water tank consisting of a single tank; and a control unit that performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization, using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid and that is stored in the medium-temperature water tank consisting of the single tank before the object to be sterilized is cooled by the cooling water.

2. The heat sterilization device according to claim 1 , wherein the control unit is configured to perform the medium-temperature water heat recovery control in a state in which the high-temperature fluid after heat sterilization is discharged from the sterilization tank.

3. The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization, using the medium-temperature water supplied from the medium-temperature water tank consisting of the single tank, before cooling of the object to be sterilized by the cooling water, and to store the medium-temperature water used in the medium-temperature water heat recovery control in the medium-temperature water tank consisting of the single tank.

4. The heat sterilization apparatus according to claim 3, wherein the control unit is configured to perform preheating control to preheat the sterilization tank using the medium-temperature water heated during the medium-temperature water heat recovery control and stored in the medium-temperature water tank consisting of a single tank, before heating of the object to be sterilized by the high-temperature fluid.

5. A first connection path is provided to connect the sterilization tank and the medium-temperature water tank consisting of a single tank to each other, The heat sterilization apparatus according to claim 4, wherein the control unit is configured to perform control to recover and store the medium-temperature water in the sterilization tank after heat recovery in the medium-temperature water tank consisting of the single tank via the first connection path, and to perform control to supply the medium-temperature water to the sterilization tank via the first connection path during preheating.

6. The heat sterilization device according to claim 4, wherein the control unit is configured to control the release of the medium-temperature water supplied from the medium-temperature water tank consisting of the single tank toward the object to be sterilized during each of preheating of the sterilization tank and heat recovery of the sterilization tank.

7. a high-temperature water tank for collecting and storing the high-temperature water, which is the high-temperature fluid after heat sterilization stored in the sterilization tank; A second connection path connecting the sterilization tank and the high-temperature water tank to each other is further provided. The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control of the sterilization tank after the high-temperature water discharged from the sterilization tank upon completion of heat sterilization of the object to be sterilized is recovered into the high-temperature water tank via the second connection path.

8. a heat transfer fluid supply unit that supplies a heat transfer fluid heated by the medium-temperature water; a heat exchanger that performs heat exchange between the medium-temperature water stored in the medium-temperature water tank consisting of a single tank and the heat transfer fluid supplied from the heat transfer fluid supply unit, The heating and sterilizing apparatus according to claim 3, wherein the control unit is configured to control the supply of the heat transfer fluid, the temperature of which has been increased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank during preheating of the sterilization tank, and to control the supply of the heat transfer fluid, the temperature of which has been decreased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank during heat recovery of the sterilization tank.

9. The cooling water, the high-temperature fluid, and the medium-temperature water discharged from the sterilization tank are discharged through a circulation path including a circulation pump for circulating the cooling water, the high-temperature fluid, and the medium-temperature water to the sterilization tank, The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control by circulating the medium-temperature water to the sterilization tank through the circulation path using the circulation pump.

10. A step of supplying a high-temperature fluid to a sterilization tank in which heat sterilization is performed using the high-temperature fluid, and heat sterilizing an object to be sterilized in the sterilization tank; Before cooling the object to be sterilized with cooling water, heat recovery from the sterilization tank after thermal sterilization is performed using medium-temperature water stored in a medium-temperature water tank consisting of a single tank, the medium-temperature water having a temperature higher than that of the cooling water and lower than that of the high-temperature fluid, the medium-temperature water being generated separately from the high-temperature fluid and stored in the medium-temperature water tank consisting of a single tank; The heat sterilization method includes a step of cooling the heat-sterilized object to be sterilized with the cooling water after heat recovery of the sterilization tank.

11. The heat sterilization method according to claim 10, further comprising a step of preheating the sterilization tank using the medium temperature water heated during the heat recovery of the sterilization tank before the high temperature fluid for heat sterilizing the object to be sterilized is supplied to the sterilization tank.

Images