JP2014226107A - Sterilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilizer capable of lowering the sterilization temperature during the step of sterilization.SOLUTION: A treatment tank 3 accommodates an article 2 to be treated, while storing water up to a preset water level. Circulation means 8 circulates storage water in the treatment tank 3 through a circulation channel 20. Heating means 9 blows steam into the circulation channel 20 for heating the circulation water. Control means controls the heating means 9 such that preset temperature inside the treatment tank 3 is maintained for heat sterilization of the article 2 to be treated. During sterilization, water feed means 4 and water discharge means 5 are controlled to gradually replace storage water in the treatment tank 3, so that the preset temperature can be lowered.

Description

  The present invention relates to a sterilization apparatus used for heat sterilization of retort foods and the like.

  Conventionally, as disclosed in Patent Document 1 below, the processing object (2) is accommodated in the processing tank (1) and water is stored, and the stored water is circulated between the heat exchanger (3). The circulating water is heated with steam in the heat exchanger (3) or cooled with cooling water from the cooling tower (8) to switch the sterilization of the workpiece (2) and subsequent cooling. Sterilizers that can do this are known.

Japanese Patent No. 4229420

  None of the conventional sterilization apparatuses can raise the sterilization temperature but lower it during the sterilization process. As long as the purpose is sterilization, the temperature in the treatment tank may be raised, but not lowered.

  However, in actual cooking, it is preferable if the sterilization temperature can be lowered in the middle of cooking that also serves as sterilization of retort foods, etc., so that it may be changed to medium heat or low heat after first heating with high heat. is there. Thereby, optimal temperature control according to a to-be-processed object is attained, and the improvement of the taste of foodstuffs and a finish can be anticipated. It is also possible to shorten the sterilization time without degrading the taste by setting the temperature change as desired.

  Therefore, the problem to be solved by the present invention is to provide a sterilization apparatus capable of lowering the sterilization temperature during the sterilization process.

  The present invention has been made in order to solve the above-mentioned problems, and the invention according to claim 1 includes a treatment tank in which an object to be treated is accommodated and water is stored up to a set water level, and the inside of the treatment tank. Circulating means for circulating the stored water through a circulation path, heating means for heating the water in the circulation path or the treatment tank, and controlling the heating means to maintain the inside of the treatment tank at a set temperature. Control means for heating and sterilizing the object to be treated, and during the sterilization, a part of the stored water in the treatment tank is replaced, or the circulating water is cooled in the circulation path, and the set temperature is set. It is a sterilizer characterized by including the process to lower.

  According to the first aspect of the present invention, the sterilization temperature can be lowered by replacing part of the stored water in the treatment tank or cooling the circulating water in the circulation path during the sterilization process. Thereby, the optimal temperature control according to a to-be-processed object is attained, for example, the improvement of the taste of foodstuffs and a finish can be anticipated. Furthermore, it is possible to shorten the sterilization time without degrading the taste by setting the temperature change as desired.

  Invention of Claim 2 is equipped with the water supply means to the said processing tank, and the drainage means to the outside of the said processing tank, and it is in the said processing tank by the said water supply means to the water level which does not immerse the said to-be-processed object. When water is stored, the stored water is circulated by the circulation means, and the set temperature is lowered to a target temperature, the water supply means intermittently enters the treatment tank as long as the water level in the treatment tank is less than the upper limit water level. Water is intermittently or continuously drained out of the treatment tank by the drainage means until the water level in the treatment tank exceeds the upper limit water level and falls below the lower limit water level. It is a sterilizer of Claim 1.

  According to invention of Claim 2, based on the water level in a processing tank, the water in a processing tank is gradually submerged without immersing a to-be-processed object by controlling a water supply means and a drainage means to predetermined. It can be replaced to lower the sterilization temperature.

  According to a third aspect of the present invention, when the set temperature is lowered to the target temperature, the water supply flow rate into the treatment tank by the water supply means and the drainage means are set so that the temperature decreasing speed becomes a set speed. The sterilization apparatus according to claim 2, wherein the waste water flow rate to the outside of the treatment tank is adjusted.

  According to the third aspect of the present invention, when the sterilization temperature is lowered, the temperature lowering speed can be adjusted as desired.

  According to a fourth aspect of the present invention, the circulation means circulates the stored water in the treatment tank between the treatment tank and a heat exchanger, and heats the circulation water by the circulation means. A heating means for supplying steam to the heat exchanger, and a cooling means for supplying cooling water to the heat exchanger to cool the circulating water by the circulation means, when lowering the set temperature to a target temperature, The sterilizer according to claim 1, wherein the water stored in the treatment tank is circulated between the heat exchanger while supplying cooling water to the heat exchanger.

  According to invention of Claim 4, sterilization temperature can be lowered | hung by cooling the circulating water in a heat exchanger, circulating water between a processing tank and a heat exchanger.

  The invention according to claim 5 is characterized in that when the set temperature is lowered to the target temperature, the flow rate of the circulating water passed through the heat exchanger is adjusted so that the temperature decreasing speed becomes the set speed. Item 5. The sterilizer according to Item 4.

  According to the fifth aspect of the present invention, when the sterilization temperature is lowered, the temperature lowering speed can be adjusted as desired.

  Furthermore, invention of Claim 6 is a sterilizer of any one of Claims 1-5 including the process of lowering | hanging the said preset temperature in multiple steps during the said sterilization.

  According to the invention described in claim 6, since the sterilization temperature can be lowered in a plurality of stages, the optimum temperature control according to the object to be processed can be performed more reliably.

  ADVANTAGE OF THE INVENTION According to this invention, the sterilization apparatus which can reduce sterilization temperature in the middle of a sterilization process is realizable.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows Example 1 of the sterilizer of this invention, and it has shown one part in cross section. It is the schematic which shows an example of the relationship between the process tank internal temperature T during driving | operation of the sterilizer of FIG. 1, and the elapsed time t, and has shown from the water supply process to a part of sterilization process. It is the schematic which shows Example 2 of the sterilizer of this invention, and has shown one part in cross section.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing Example 1 of the sterilizer 1 of the present invention, and a part thereof is shown in cross section. The sterilization apparatus 1 of the present embodiment is an apparatus that cools the workpiece 2 after heat sterilization. The workpiece 2 is not particularly limited, but is typically a food material sealed in a container, such as retort food or canned food.

  The sterilization apparatus 1 of the present embodiment includes a treatment tank 3 in which an object to be treated 2 is accommodated, a water supply means 4 into the treatment tank 3, a drainage means 5 to the outside of the treatment tank 3, and a treatment tank 3 Pressurizing means 6, exhaust means 7 to the outside of the processing tank 3, circulating means 8 for stored water in the processing tank 3, heating means 9 for heating the circulating water, and control means for controlling these means ( (Not shown).

  The treatment tank 3 is a hollow container that accommodates the workpiece 2. The shape of the treatment tank 3 is not particularly limited. In the present embodiment, the treatment tank 3 includes a horizontally disposed cylindrical material, and this cylindrical material has one opening closed and the other opening opened and closed by a door. It is possible. By opening the door, the workpiece 2 can be taken in and out of the processing tank 3, and by closing the door, the opening of the processing tank 3 can be closed airtight. In addition, the to-be-processed object 2 is hold | maintained above the bottom face in the processing tank 3 by mounting on the trolley | bogie.

  The processing tank 3 is provided with a temperature sensor 10 that detects the temperature in the processing tank 3 and a water level detector (not shown) that detects the water level in the processing tank 3.

  The water supply means 4 supplies water into the treatment tank 3 through the water supply path 11. The water supply path 11 is connected to the bottom of the processing tank 3, and a water supply pump 12 and a water supply valve 13 are provided toward the processing tank 3. By opening the water supply valve 13 in a state where the water supply pump 12 is operated, water from the water supply source can be supplied into the processing tank 3 and water can be stored in the processing tank 3. In a present Example, water is stored in the processing tank 3 to the setting water level which does not immerse the to-be-processed object 2 accommodated in the processing tank 3. FIG.

  The drainage means 5 discharges water from the treatment tank 3 through the drainage channel 14. The drainage channel 14 is connected to the bottom of the treatment tank 3, and a drainage valve 15 is provided. By opening the drain valve 15, the water in the treatment tank 3 can be discharged to the outside.

  The pressurizing means 6 supplies pressurized air (in other words, compressed air) into the processing tank 3 through the pressurizing passage 16. By opening the pressurization valve 17 provided in the pressurization path 16, the pressurized air from a pressurized air source can be supplied in the processing tank 3, and the inside of the processing tank 3 can be pressurized to the pressure exceeding atmospheric pressure. .

  The exhaust means 7 exhausts the gas from the inside of the processing tank 3 under a pressure exceeding the atmospheric pressure via the exhaust path 18. The exhaust path 18 is connected to the upper part of the processing tank 3 and is provided with an exhaust valve 19. When the exhaust valve 19 is opened while the inside of the processing tank 3 is at a pressure exceeding the atmospheric pressure, the gas in the processing tank 3 is discharged to the outside through the exhaust path 18, and the pressure in the processing tank 3 may be lowered. it can.

  The circulation means 8 includes a circulation path 20 and a circulation pump 21. One end of the circulation path 20 is connected to the bottom of the processing tank 3, and the other end is connected to the nozzle 22 in the processing tank 3. More specifically, the circulation path 20 from the bottom of the treatment tank 3 is connected to a nozzle 22 in the treatment tank 3 via a circulation pump 21. This nozzle 22 is provided in the side part and / or upper part in the processing tank 3, and injects the water from the circulation pump 21 toward the to-be-processed object 2. FIG.

  The heating means 9 heats the circulating water from the circulation means 8. Although the structure of the heating means 9 is not particularly limited, in this embodiment, the heating means 9 is a means for supplying steam into the circulation path 20. Specifically, the heating means 9 of this embodiment supplies steam into the circulation path 20 via the steam supply path 23. A steam supply valve 24 is provided in the steam supply path 23. The inside of the processing tank 3 can be adjusted to a desired temperature by adjusting the opening of the steam supply valve 24 based on the temperature detected by the temperature sensor 10 provided in the processing tank 3.

  The control means is a controller (not shown) that controls each of the means 4 to 9 based on the elapsed time as well as the detection signals of the temperature sensor 10 and the water level detector. Specifically, in addition to the water supply pump 12, the water supply valve 13, the drain valve 15, the pressurizing valve 17, the exhaust valve 19, the circulation pump 21, the steam supply valve 24, the temperature sensor 10 and the water level detector are connected to the controller. Has been. And a controller performs the heat sterilization of the to-be-processed object 2 in the processing tank 3, and subsequent cooling according to a predetermined procedure (program) so that it may mention below. Typically, a water supply process, a transition process, a sterilization process, a cooling process, and a drainage process are sequentially performed.

  FIG. 2 is a schematic diagram showing an example of the relationship between the temperature T in the processing tank and the elapsed time t during operation of the sterilization apparatus 1 of the present embodiment, showing from the water supply step S1 to a part of the sterilization step S3. Yes. In the sterilization step S3, as will be described later, the inside of the processing tank 3 is maintained at a set temperature (sterilization temperature), but the set temperature can be changed midway. In FIG. 2, the sterilization step S3 includes a step of lowering the inside of the processing tank 3 from the first set temperature T1 to the second set temperature T2.

  Hereinafter, each step will be described. Prior to the operation of the sterilizer 1, the workpiece 2 is accommodated in the treatment tank 3, and the door of the treatment tank 3 is closed. In this state, the exhaust valve 19 is opened, the other valves 13, 15, 17, and 24 are closed, and the pumps 12 and 21 are stopped.

(1) Water supply process S1
In the water supply process, water is supplied into the treatment tank 3 by the water supply means 4 to a set water level at which the workpiece 2 in the treatment tank 3 is not immersed, and the water is stored in the treatment tank 3. Specifically, the water supply valve 13 may be opened while the water supply pump 12 is operated. When water is stored in the treatment tank 3 up to the set water level, the water supply valve 13 is closed and the water supply pump 12 is stopped to end the water supply process.

(2) Transition process S2
In the transition step, while circulating water in the treatment tank 3 is circulated by the circulation means 8, the circulation water is heated by the heating means 9, and the temperature in the treatment tank 3 is changed to the sterilization temperature (the sterilization temperature is changed in the sterilization process). In this case, the temperature is the sterilization temperature immediately after the start of the sterilization process, and is increased to the first set temperature T1) in FIG. Specifically, by operating the circulation pump 21, the water from the inner bottom of the treatment tank 3 is returned from the nozzle 22 to the treatment tank 3 through the circulation path 20, so that the water in the treatment tank 3 is recovered. Circulate. At this time, the steam supply valve 24 is opened and the steam is supplied into the circulation path 20 to heat the circulating water. In addition, if the water stored in the treatment tank 3 in the water supply process is supplied to the circulation path 20 in the transition process, and the water level in the treatment tank 3 is lowered, the treatment tank 2 is not immersed in the treatment tank. Water is appropriately supplied into 3.

  Thus, although the temperature in the processing tank 3 is raised gradually, the to-be-processed object 2 expand | swells by heating, and there exists a possibility that a container (retort pouch etc.) may burst. Therefore, in order to prevent this, the inside of the processing tank 3 is gradually pressurized by the pressurizing means 6 to a pressure exceeding the atmospheric pressure (higher than the saturated vapor pressure corresponding to the temperature in the processing tank). Specifically, by controlling the pressurization valve 17 and the exhaust valve 19, pressurization according to the temperature in the processing tank 3 is performed.

  Thereafter, water circulation by the circulation means 8 is continued until the end of the cooling step. Further, the pressurizing means 6 pressurizes the treatment tank 3 after the temperature in the treatment tank 3 rises to the sterilization temperature, and continues to a pressure higher than the saturated vapor pressure corresponding to the treatment tank temperature until the end of the cooling step. The In addition, when changing sterilization temperature in a sterilization process, the pressure in the processing tank 3 may be fluctuate | varied with it, and you may hold | maintain constant. In the former case, the pressure in the processing tank 3 is changed to a pressure that is higher than the saturated vapor pressure at that temperature by a predetermined pressure in accordance with the temperature change in the processing tank 3. In the latter case, the pressure in the processing tank 3 is kept constant regardless of the temperature change in the processing tank 3, but the holding pressure is always higher than the saturated vapor pressure corresponding to the temperature in the processing tank. Is set. In other words, the inside of the processing tank 3 is maintained at a pressure higher than the saturated steam pressure at the highest sterilization temperature by a predetermined pressure.

(3) Sterilization process S3
In the sterilization step, the temperature in the treatment tank 3 is maintained at a set temperature (sterilization temperature), and the workpiece 2 is heated and sterilized. Specifically, the opening degree of the steam supply valve 24 is adjusted so that the temperature detected by the temperature sensor 10 is maintained at the set temperature while circulating the stored water in the treatment tank 3 by the circulation means 8.

  The set temperature can be raised or lowered during the sterilization process. In this embodiment, as shown in FIG. 2, in the sterilization step, after maintaining the first set time at the first set temperature T1, the temperature is lowered to the second set temperature T2 lower than the first set temperature T1, A step of maintaining the second set time at the second set temperature T2.

  In order to raise the set temperature, the heating means 9 is controlled as in the transition step. On the other hand, the set temperature is lowered by controlling the water supply means 4 and the drainage means 5 so that the stored water in the treatment tank 3 is gradually replaced while the heating by the heating means 9 is stopped.

  Specifically, the water supply valve 13 and the drain valve 15 are controlled to gradually replace the stored water in the treatment tank 3 with new water from the water supply source. However, when the first set temperature T1 is lowered to the second set temperature T2, the processing tank 3 is set so that the temperature decrease speed becomes the set speed, in other words, the temperature decrease curve α in FIG. It is preferable to adjust the water supply flow rate to the inside and the drainage flow rate to the outside of the treatment tank 3.

  That is, if the water supply valve 13 is simply opened, water may be supplied too rapidly into the processing tank 3, or if the drain valve 15 is simply opened, the water may be discharged too rapidly outside the processing tank 3. is there. Therefore, when the set temperature is lowered to the target temperature (when the first set temperature T1 is lowered to the second set temperature T2 in FIG. 2), the water supply valve 13 and the drain valve 15 are opened and closed intermittently, thereby supplying the water supply flow rate and the drainage flow rate. It is good to adjust.

  In the present embodiment, as long as the water level in the treatment tank 3 is less than the upper limit water level, the water supply valve 13 is opened intermittently and the water supply means 4 intermittently supplies water into the treatment tank 3. For example, the water supply valve 13 is repeatedly opened for a predetermined opening time and closed for a predetermined closing time. When the water level in the treatment tank 3 exceeds the upper limit water level, the drain valve 15 is intermittently opened until the water level falls below the lower limit water level, and the drainage means 5 intermittently drains the treatment tank 3. For example, the drain valve 15 is repeatedly opened for a predetermined opening time and closed for a predetermined closing time. In addition, the to-be-processed object 2 is not immersed in the stored water in the processing tank 3 also in an upper limit water level. Further, during this time, it is sufficient for the water supply pump 12 to continue operating, but depending on circumstances, the water supply pump 12 may be started and stopped so as to interlock with the opening and closing of the water supply valve 13.

  By the way, instead of intermittently opening the water supply valve 13, as shown by a two-dot chain line in FIG. 1, a bypass water supply path 25 is provided in the water supply path 11 by connecting the front and rear of the water supply valve 13. A bypass water supply valve 26 may be provided in the water supply path 25. The water supply flow rate by opening the bypass water supply valve 26 is set to be smaller than the water supply flow rate by opening the water supply valve 13. Therefore, at the time of water supply for lowering the temperature in the treatment tank, the bypass water supply valve 26 may be opened instead of the water supply valve 13. That is, in the sterilization process, when water is supplied into the processing tank 3 in order to lower the set temperature to the target temperature, the bypass water supply valve 26 is maintained in an open state and continuously into the processing tank 3 at a relatively small flow rate. You just have to supply water.

  Similarly, instead of intermittently opening the drain valve 15, as shown by a two-dot chain line in FIG. 1, the drain path 14 is provided with a bypass drain path 27 by connecting the front and rear of the drain valve 15. A bypass drain valve 28 may be provided in the bypass drain path 27. The drainage flow rate by opening the bypass drainage valve 28 is set to be smaller than the drainage flow rate by opening the drainage valve 15. Therefore, when draining to lower the temperature in the treatment tank, the bypass drain valve 28 may be opened instead of the drain valve 15. That is, in the sterilization process, in order to lower the set temperature to the target temperature, the bypass drain valve 28 is opened until the water level in the treatment tank 3 exceeds the upper limit water level and falls below the lower limit water level by supplying water into the treatment tank 3. The state may be maintained and drained continuously to the outside of the processing tank 3 with a relatively small flow rate.

  Alternatively, instead of providing the bypass water supply valve 26 and the bypass drain valve 28, the water supply valve 13 and the drain valve 15 are configured from valves whose opening degree can be adjusted, and when the temperature in the treatment tank is lowered, the water supply valve 13 Alternatively, the opening degree of the drain valve 15 may be reduced to supply and drain water to the treatment tank 3. Alternatively, the feed water pump 12 may be inverter-controlled to adjust the flow rate.

  In any case, the temperature in the processing tank 3 can be lowered by gradually replacing the stored water in the processing tank 3 during sterilization. In FIG. 2, after the first set temperature T1 can be lowered to the second set temperature T2, the water supply / drainage to the processing tank 3 is stopped, and the second set temperature T2 is maintained for the second set time. What is necessary is just to adjust the opening degree of the steam supply valve 24 based on the temperature in a tank.

  Thus, when desired sterilization is performed, the steam supply valve 24 is closed, the steam supply into the circulation path 20 is stopped, and the sterilization process is terminated. In addition, although the example which lowers 1st preset temperature T1 to 2nd preset temperature T2 is shown in FIG. 2, not only this but preset temperature can be changed suitably in the middle of a sterilization process. For example, in FIG. 2, the set temperature is raised or lowered to a desired temperature before or after the maintaining step at the first set temperature T1, or before or after the maintaining step at the second set temperature T2, and held for a desired time. There may be one or a plurality of steps.

  In particular, a step of lowering the set temperature by a plurality of stages during sterilization may be included. For example, in FIG. 2, the set temperature is lowered by one step, but may be lowered by two steps or by three or more steps. As described above, according to the sterilization apparatus 1 of the present embodiment, the set temperature in the sterilization process is raised or lowered stepwise, and the optimum temperature control according to the workpiece 2 can be performed.

(4) Cooling process In the cooling process, the temperature in the processing tank 3 is gradually replaced by the water supply means 4 and the drainage means 5 while circulating the water in the processing tank 3. Lower. This replacement can also be performed by the same operation as when the set temperature is lowered in the sterilization process.

  When the set time elapses from the start of the cooling process or when the set time elapses after the temperature in the treatment tank 3 (cooling water temperature) falls below the set temperature, the cooling process ends. At this time, the circulation by the circulation means 8 is also stopped, but the pressurization in the treatment tank 3 by the pressure means 6 may be continued until the drainage is completed in the drainage process.

(5) Drainage process In the drainage process, the drainage means 5 drains water from the treatment tank 3. Specifically, water is discharged to the outside by opening the drain valve 15. If the drainage means 5 drains while the inside of the treatment tank 3 is pressurized by the pressurizing means 6, drainage from the treatment tank 3 can be performed quickly. Thereafter, the pressurizing valve 17 is closed, the exhaust valve 19 is opened, the inside of the processing tank 3 is returned to atmospheric pressure, the door of the processing tank 3 is opened, and the workpiece 2 can be taken out from the processing tank 3. it can.

  As described above, according to the sterilization apparatus 1 of the present embodiment, not only the sterilization temperature can be raised as desired during the sterilization process, but also the sterilization temperature can be lowered as desired. Therefore, optimum temperature control according to the workpiece 2 is possible. In particular, in accordance with the object 2 to be processed, an operation can be performed in which sterilization is performed at a high temperature in the initial stage of sterilization and then the sterilization temperature is lowered. In other words, by lowering the sterilization temperature in the middle, it is possible to perform heating processing as if it was first heated with a high flame and then changed to a medium or low flame. Thereby, the improvement of the taste of a foodstuff and a finish can be expected. Also, for example, sterilization, which conventionally required X minutes at 80 ° C., reduces the taste while shortening the sterilization time, such as Y minutes at 100 ° C. and Z minutes at 80 ° C. (X> Y + Z). It becomes possible to cook without.

  FIG. 3 is a schematic view showing Example 2 of the sterilizer 1 of the present invention, and a part thereof is shown in cross section. The sterilizer 1 of the second embodiment is basically the same as the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the circulating water is heated by injecting steam into the circulation path 20, while the cooling of the circulating water is performed by supplying and draining water into the treatment tank 3. In the second embodiment, the circulation path is heated. 20, a heat exchanger 29 is provided, and the circulating water is heated by indirectly exchanging the circulating water and steam in the heat exchanger 29, while the circulating water is cooled in the heat exchanger 29. And indirect heat exchange.

  The sterilization apparatus 1 according to the second embodiment includes a treatment tank 3 in which an object to be treated 2 is accommodated, water supply means 4 into the treatment tank 3, drainage means 5 to the outside of the treatment tank 3, and inside the treatment tank 3. Pressurizing means 6, exhaust means 7 to the outside of the treatment tank 3, circulation means 8 for circulating water between the treatment tank 3 and the heat exchanger 29, and heating the circulating water by the circulation means 8 Heating means 9 for supplying steam to the heat exchanger 29, cooling means 30 for supplying cooling water to the heat exchanger 29 in order to cool the circulating water by the circulating means 8, and steam condensed water (drain) by the heating means 9 ) And a control means (not shown) for controlling these means. Among them, the treatment tank 3, the water supply means 4, the drainage means 5, the pressurization means 6, and the exhaust means 7 are the same as those in the first embodiment, and thus the description thereof is omitted.

  The heat exchanger 29 circulates water between the treatment tank 3 and indirectly heat-exchanges the circulating water and steam or cooling water. That is, in the heat exchanger 29, water from the treatment tank 3 is passed by the circulation means 8 and steam is passed from the heating means 9 to heat the circulating water or to cool the circulating water. Cooling water is passed from the cooling means 30.

  The circulation means 8 circulates water between the treatment tank 3 and the heat exchanger 29. The circulation means 8 includes a circulation path 20 and a circulation pump 21. One end of the circulation path 20 is connected to the bottom of the treatment tank 3, and the circulation path 20 from the bottom of the treatment tank 3 sequentially passes through the circulation pump 21 and the heat exchanger 29, and the other end is the treatment tank 3. It is connected to the inner nozzle 22.

  The circulation means 8 is preferably capable of adjusting the flow rate of the circulating water passing through the heat exchanger 29. For this purpose, the circulation pump 21 may be inverter-controlled, or a valve may be provided in the circulation path 20 to adjust the opening thereof. In this embodiment, the circulation path 20 is provided before and after the heat exchanger 29. A bypass path 32 is provided so as to be connected, and a three-way valve 33 is provided at a branch portion between the circulation path 20 and the bypass path 32. By controlling the three-way valve 33, the circulating water from the circulation pump 21 is returned to the treatment tank 3 through the heat exchanger 29, or is returned to the treatment tank 3 through the bypass path 32 without passing through the heat exchanger 29. The distribution ratio is adjustable.

  The heating means 9 supplies steam to the heat exchanger 29 to heat the circulating water by the circulation means 8. The heating means 9 includes a steam supply path 23 that supplies steam from the boiler to the heat exchanger 29, and a steam supply valve 24 is provided in the steam supply path 23. During the circulation by the circulation means 8, the temperature in the treatment tank 3 can be adjusted as desired by adjusting the opening of the steam supply valve 24 based on the temperature detected by the temperature sensor 10.

  The cooling means 30 supplies cooling water to the heat exchanger 29 to cool the circulating water by the circulation means 8. The cooling means 30 includes a cooling tower 34, and the water cooled by the cooling tower 34 is supplied to the heat exchanger 29 via the cooling water feed path 36 by the water pump 35, and the water after passing through the heat exchanger 29. Is returned to the cooling tower 34 via the cooling water return path 37. In the case of the illustrated example, the cooling water feed path 36 and the steam supply path 23 are a common pipe line on the heat exchanger 29 side.

  The cooling water feed path 36 is provided with a cooling water feed valve 38, while the cooling water return path 37 is provided with a cooling water return valve 39. The junction between the cooling water feed path 36 and the steam supply path 23 is arranged downstream (on the heat exchanger 29 side) from the cooling water feed valve 38 and the steam supply valve 24.

  When the water supply pump 35 is operated with the cooling water feed valve 38 and the cooling water return valve 39 opened, the cooling water can be circulated between the cooling tower 34 and the heat exchanger 29. On the other hand, if the cooling water feed valve 38 and the cooling water return valve 39 are closed, the flow of the cooling water to the heat exchanger 29 can be stopped.

  The drain discharge means 31 discharges the condensed water of the steam supplied to the heat exchanger 29 by the heating means 9 to the outside. The drain discharge means 31 is provided on the upstream side (heat exchanger side) of the cooling water return valve 39 in the cooling water return path 37, and is connected to a drain discharge path 40 branched from the cooling water return path 37. The steam trap 42 and the check valve 43 are provided in order. When the steam is supplied to the heat exchanger 29, the condensate of the steam can be discharged to the outside by opening the drain discharge valve 41.

  The operation method of this embodiment is basically the same as that of the first embodiment, but differs in the method of heating and cooling the circulating water. Heating of the circulating water in the transition process and the sterilization process is performed by the heating means 9 in the heat exchanger 29. Specifically, by operating the circulation pump 21, the water from the inner bottom of the processing tank 3 is returned from the nozzle 22 into the processing tank 3 through the heat exchanger 29, thereby exchanging heat with the processing tank 3. Water is circulated to and from the vessel 29. At this time, all the water from the circulation pump 21 may be returned to the treatment tank 3 through the heat exchanger 29. During this circulation, the steam supply valve 24 is opened to supply steam to the heat exchanger 29. Thereby, in the heat exchanger 29, circulating water and steam are heat-exchanged, and heating of circulating water can be aimed at. By adjusting the opening degree of the steam supply valve 24 based on the temperature detected by the temperature sensor 10, the temperature in the processing tank 3 can be adjusted. The cooling water feed valve 38 and the cooling water return valve 39 are closed, and the drain discharge valve 41 is opened. By opening the drain discharge valve 41, the condensed water of the steam is discharged through the steam trap 42.

  Cooling of the circulating water in the sterilization process or the cooling process is performed by the cooling means 30 in the heat exchanger 29. Specifically, by operating the circulation pump 21, the water from the inner bottom of the processing tank 3 is returned from the nozzle 22 into the processing tank 3 through the heat exchanger 29, thereby exchanging heat with the processing tank 3. Water is circulated to and from the vessel 29. In addition, the cooling water may be circulated through the heat exchanger 29 by operating the cooling tower 34 and the water pump 35 with the cooling water feed valve 38 and the cooling water return valve 39 opened. At this time, the steam supply valve 24 and the drain discharge valve 41 are closed.

  When the temperature in the treatment tank 3 is lowered, it is preferable to adjust the flow rate of the circulating water passed through the heat exchanger 29 so that the temperature lowering speed becomes the set speed. Specifically, the opening degree of the three-way valve 33 may be adjusted so that the temperature decreases at a set speed while monitoring the temperature detected by the temperature sensor 10. When the set temperature falls to the target temperature, the entire amount of circulating water from the circulation pump 21 is passed through the heat exchanger 29, while steam is again supplied to the heat exchanger 29 by the heating means 9, and the steam supply valve 24 is opened. The temperature in the processing tank 3 may be maintained by adjusting the degree. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  The sterilization apparatus 1 of the present invention is not limited to the configuration of each of the above embodiments, and can be changed as appropriate. In particular, during the sterilization of the object 2 to be processed, if a part of the stored water in the treatment tank 3 is replaced or the circulating water is cooled in the circulation path 20 to include a step of lowering the sterilization temperature, the other configurations are as follows. It can be changed as appropriate.

  For example, it can be applied to a so-called hot water storage type sterilizer. In that case, in the treatment tank 3, the workpiece 2 is submerged in hot water for sterilization. During the sterilization, in order to lower the set temperature, the storage in the treatment tank 3 is performed as in the first embodiment. Whether the water is gradually replaced (however, in this case, the object to be treated 2 is submerged in the stored water in the treatment tank 3 even at the lower limit water level), or heat exchange with the treatment tank 3 as in the second embodiment. Cooling with cooling water in the heat exchanger 29 may be performed while water is circulated between the units 29.

  Even when the water is circulated between the treatment tank 3 and the heat exchanger 29 as in the sterilization apparatus 1 of the second embodiment, when the temperature in the treatment tank 3 is lowered, the heat exchanger 29 In addition to passing cooling water through, the water stored in the treatment tank 3 may be replaced in the same manner as in the first embodiment.

  In each of the above embodiments, the heating means 9 heated the circulating water in the circulation path 20, but depending on the case, the stored water in the processing tank 3 may be injected by injecting steam into the stored water in the processing tank 3. May be heated. Further, in each of the above embodiments, the heating means 9 is constituted by a steam supply means, but it may be constituted by an electric heater or the like depending on circumstances.

  In the second embodiment, the three-way valve 33 is controlled in order to adjust the flow rate of the circulating water passing through the heat exchanger 29. However, instead of the three-way valve 33 being installed, the circulation path 20 and / or the bypass path 32 is used. Of these, a valve may be provided between the bifurcation part and the junction part, and the opening degree of the valve may be adjusted. Alternatively, instead of adjusting the flow rate of the circulating water passing through the heat exchanger 29, the temperature decreasing rate in the treatment tank 3 may be adjusted by adjusting the flow rate of the cooling water passing through the heat exchanger 29 in some cases. Also good.

  Furthermore, in the said Example 2, the cooling means 30 is good also as a cold water manufacturing apparatus (chiller) using a refrigerator instead of the cooling tower 34. FIG. In that case, the cold water may be recycled or disposable.

DESCRIPTION OF SYMBOLS 1 Sterilizer 2 To-be-processed object 3 Processing tank 4 Water supply means 5 Drainage means 6 Pressurization means 7 Exhaust means 8 Circulation means 9 Heating means 10 Temperature sensor 20 Circulation path 29 Heat exchanger 30 Cooling means 31 Drain discharge means 32 Bypass path 33 Three-way valve

Claims (6)

A treatment tank in which the object to be treated is stored and water is stored to the set water level;
A circulation means for circulating the stored water in the treatment tank through a circulation path;
Heating means for heating water in the circulation path or the treatment tank;
Control means for controlling the heating means so as to maintain the inside of the treatment tank at a set temperature, and heating and sterilizing the object to be treated,
During the sterilization, the sterilizer includes a step of lowering the set temperature by replacing a part of the stored water in the treatment tank or cooling the circulating water in the circulation path. Water supply means into the treatment tank, and drainage means to the outside of the treatment tank,
Up to a water level where the workpiece is not immersed, water is stored in the treatment tank by the water supply means, and the stored water is circulated by the circulation means.
When lowering the set temperature to the target temperature, as long as the water level in the treatment tank is less than the upper limit water level, water is intermittently or continuously supplied into the treatment tank by the water supply means, while the water level in the treatment tank is The sterilizer according to claim 1, wherein when the water level exceeds the upper limit water level, the water is intermittently or continuously discharged outside the treatment tank by the drainage means until the water level falls below the lower limit water level. When the set temperature is lowered to the target temperature, the water supply flow rate into the treatment tank by the water supply means and the waste water flow rate to the outside of the treatment tank by the drainage means are set so that the temperature decrease rate becomes a set speed. The sterilizer according to claim 2, wherein the sterilizer is adjusted. The circulation means circulates the stored water in the treatment tank between the treatment tank and a heat exchanger,
Heating means for supplying steam to the heat exchanger in order to heat the circulating water by the circulation means;
A cooling means for supplying cooling water to the heat exchanger in order to cool the circulating water by the circulation means,
The stored water in the treatment tank is circulated between the heat exchanger and cooling water is supplied to the heat exchanger when the set temperature is lowered to a target temperature. Sterilization equipment. The sterilizer according to claim 4, wherein when the set temperature is lowered to a target temperature, a flow rate of circulating water that is passed through the heat exchanger is adjusted so that a temperature decrease rate becomes a set rate. The sterilizer according to any one of claims 1 to 5, further comprising a step of lowering the set temperature in a plurality of stages during the sterilization.

Images