JP2019205377A - Sterilizer - Google Patents

Abstract

To provide a sterilizer to heat an article to be processed by injecting steam into a processing tank, where temperature is easily controlled and temperature unevenness is prevented by agitating the article.SOLUTION: A sterilizer is equipped with a processing tank 2 to house an article to be processed, steam supply means 3 to supply steam into the processing tank 2 and heat the article to be processed, and control means to control the steam supply means 3. The steam supply means 3 includes a steam supply shutoff valve 16 to switch on and off steam supply and a steam supply valve 17 of which the opening is adjustable in series on a steam supply line 14 to the processing tank 2. In a sterilizing step to heat the article to be processed, the steam supply shutoff valve 16 is switched on and off, while the opening of the steam supply valve 17 is fixed. In a heating step followed by the sterilizing step, preferably, the opening of the steam supply valve 17 is gradually reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sterilizer used for heat sterilization of an object to be processed such as retort food, and more particularly to a sterilizer for heating the object to be processed by blowing steam into a processing tank.

  Conventionally, an apparatus disclosed in Patent Document 1 below is known as a sterilization apparatus that heats an object to be processed by blowing steam into a treatment tank. In this apparatus, a sterilization process for injecting steam to an object to be processed (object to be sterilized r) stored in a processing tank (retort 10) and a cooling process for cooling the object to be processed with cooling water are sequentially executed. . In the cooling step, first, the cooling water is sent to the bottom of the treatment tank to the extent that the treatment object is not flooded, the cooling water is heated with the residual heat of the treatment tank, and then the cooling water is sprayed onto the treatment object. At the same time, the object to be treated is gradually cooled by gradually supplying and discharging the cooling water and gradually lowering the water temperature.

JP-A-6-181967 (Claim 1, paragraphs 0021-0031, FIG. 1)

  In the sterilizer, a sterilization step for maintaining the inside of the treatment tank at the sterilization temperature is performed after the temperature raising step for raising the inside of the treatment tank to the sterilization temperature. The temperature adjustment in these processes is performed by controlling the supply of steam into the treatment tank. In the prior art, the opening and closing of the valve (V5L) is switched by on / off control to control the steam supply into the processing tank. However, in the temperature raising process and the sterilization process, there is the following inconvenience only by controlling on / off of a predetermined valve. That is, in order to increase the rate of temperature increase in the temperature increasing step, if the flow rate when the valve is opened is large, overshoot is likely to occur in the sterilizing step. On the other hand, in order to prevent overshoot in the sterilization process, if the flow rate when the valve is opened is small, the temperature increase rate is inferior in the temperature increase process.

  In order to prevent such inconvenience, the following problem remains even when the opening degree of the valve is adjusted using, for example, a proportional control valve. That is, in the sterilizer of the type that supplies steam directly into the treatment tank and heats the object to be treated in the treatment tank, just adjusting the amount of steam supply into the treatment tank by adjusting the opening of the valve, The gas in the treatment tank cannot be stirred. Specifically, as a premise, there is a case where it is desired to pressurize the inside of the treatment tank with compressed air in order to prevent the rupture of a container (such as a retort pouch) due to the expansion of the treatment object while the treatment object is heated. In this case, since steam and air coexist in the treatment tank, temperature unevenness occurs unless the treatment tank is agitated. However, if steam supply control into the treatment tank is performed only by adjusting the opening of the valve, the valve opening changes continuously during the sterilization process, so stirring in the treatment tank by the steam jet when the valve is open is difficult. Become.

  Therefore, the problem to be solved by the present invention is to sterilize the inside of the processing tank with a simple configuration and control in a sterilizer that heats an object to be processed by blowing steam into the processing tank. This is to prevent temperature unevenness.

  The present invention has been made in order to solve the above-mentioned problems, and the invention according to claim 1 is directed to a processing tank in which an object to be processed is stored, and steam to be supplied into the processing tank. A steam supply means for heating, and a control means for controlling the steam supply means, wherein the steam supply means is a steam supply shut-off valve that switches on / off the presence or absence of steam supply to the steam supply path into the treatment tank; In the sterilization step of heating the workpiece to be processed, the opening and closing of the steam supply shut-off valve is switched in a state of fixing the opening of the steam supply valve. The sterilizing apparatus is characterized.

  According to the first aspect of the present invention, the steam supply passage into the treatment tank is provided with a steam supply shut-off valve that switches on / off the presence or absence of steam supply and a steam supply valve whose opening degree can be adjusted in series. . And in the sterilization process, with the opening degree of the steam supply valve fixed, by switching the opening and closing of the steam supply shut-off valve, it is possible to stir the processing tank by the steam jet when the steam supply shut-off valve is opened. Thus, temperature unevenness can be prevented. The on / off control of the steam supply shut-off valve is switched by on / off control. By adjusting the steam supply flow rate when the steam supply shut-off valve is opened, the temperature inside the treatment tank can be easily adjusted.

  The invention according to claim 2 sequentially executes a temperature raising step for raising the inside of the treatment tank to the sterilization temperature and a sterilization step for keeping the inside of the treatment tank at the sterilization temperature. The sterilizer according to claim 1, wherein the opening degree of the steam valve is reduced stepwise.

  According to the second aspect of the present invention, in the temperature raising process, the opening degree of the steam supply valve is reduced stepwise to prevent the temperature in the treatment tank from overshooting, and to the sterilization process. Transition can be facilitated.

  Invention of Claim 3 is equipped with the water supply means to the said processing tank, and the drainage means to the outside of the said processing tank, In the cooling process after the said sterilization process, in the state which closed the said steam supply shut-off valve 3. The sterilizer according to claim 1 or 2, wherein water is stored in the treatment tank by the water supply means up to a water level at which the treatment object is immersed, and the treatment object is cooled. It is.

  According to invention of Claim 3, in a cooling process, water can be stored in a processing tank to the water level which immerses a to-be-processed object, and a to-be-processed object can be cooled with a comparatively large amount of water.

  Invention of Claim 4 is further equipped with the circulation means to inject and return the water from the bottom part in the said processing tank to the to-be-processed object in the said processing tank, The water supply to the said processing tank by the said water supply means The sterilizing apparatus according to claim 3, wherein the circulating means is operated when the stored water in the treatment tank becomes a set water level or higher or the temperature of the stored water becomes a set temperature or lower.

  According to the fourth aspect of the invention, the stored water can be circulated by the circulation means, and the object to be treated can be quickly cooled without unevenness. Moreover, when the water supplied to the treatment tank is supplied to the treatment tank, when the stored water in the treatment tank becomes higher than the set water level or the temperature of the stored water becomes lower than the set temperature, the circulation means is operated to perform efficient cooling. Can be planned. If circulation by the circulation means is started on condition that the temperature of the stored water is lower than the set temperature or higher than the water level at such temperature, there is no need to use a circulation pump with a high heat resistant temperature. This cooling system can be eliminated.

  Further, in the cooling process according to the fifth aspect of the present invention, in the cooling step, instead of storing water in the treatment tank up to a water level where the treatment object is immersed, the treatment is performed up to a water level where the treatment object is not immersed. 5. The sterilizer according to claim 4, wherein water is stored in a tank, and the stored water is jetted back to the object to be processed by the circulation means to cool the object to be processed. It is.

  According to the fifth aspect of the present invention, in the cooling step, water is stored in the treatment tank up to a water level at which the treatment object is not immersed, and the stored water is injected onto the treatment object by the circulation means. The processed material can be cooled.

  According to the present invention, in a sterilization apparatus that heats an object to be processed by blowing steam into the treatment tank, the temperature can be easily adjusted with a simple configuration and control, and the treatment tank is stirred to prevent temperature unevenness. can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the sterilizer of one Example 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 a sterilizing apparatus 1 according to an embodiment 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 heats and sterilizes an object to be processed, and is configured to be able to cool the object to be processed after sterilization. The object to be treated is not particularly limited, but is typically a food material sealed in a container such as a retort food or canned food.

  The sterilizer 1 of the present embodiment includes a treatment tank 2 in which an object to be treated is accommodated, a steam supply means 3 into the treatment tank 2, a water supply means 4 into the treatment tank 2, and the outside of the treatment tank 2. The discharge means 5, the compressed air supply means 6 into the treatment tank 2, the exhaust means 7 to the outside of the treatment tank 2, the vacuum release means 8 in the treatment tank 2, and these means 3 to 8 are controlled. Control means (not shown).

  The processing tank 2 is a hollow container that accommodates an object to be processed. The processing tank 2 is not particularly limited in its shape, but includes a cylindrical material arranged horizontally in this embodiment, 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 object to be processed can be taken in and out of the processing tank 2, and by closing the door, the opening of the processing tank 2 can be closed airtight.

  In the processing tank 2, a pressure sensor 9 that detects a pressure in the processing tank 2, a temperature sensor 10 that detects a temperature in the processing tank 2, and a temperature of an object to be processed accommodated in the processing tank 2 are detected. A product temperature sensor 11 and a water level sensor 12 for detecting the water level in the treatment tank 2 are provided. Moreover, it is preferable that the treatment tank 2 is provided with a bleeder valve 13 for leaking the gas in the treatment tank 2 to the outside during the sterilization process.

  The steam supply means 3 supplies steam into the processing tank 2 through the steam supply path 14. In the present embodiment, a steam supply nozzle 15 is provided in the lower part of the processing tank 2 (lower than the object to be processed), and steam from the steam supply path 14 is passed through the steam supply nozzle 15. Supplied in. The steam supply passage 14 is provided with a steam supply shut-off valve 16 for switching on / off of steam supply and a steam supply valve 17 whose opening degree can be adjusted in series. In the illustrated example, the steam supply passage 14 is provided with the steam supply shutoff valve 16 and the steam supply valve 17 in this order toward the treatment tank 2. And the steam supply cutoff valve 16 may be provided in this order. In any case, the steam from the steam supply source can be supplied into the processing tank 2 by opening the steam supply shutoff valve 16, and the steam supply flow at that time can be changed by the opening of the steam supply valve 17. It is said.

  The water supply means 4 supplies water into the treatment tank 2 through the water supply path 18. In this embodiment, a watering nozzle 19 is provided in the upper part of the processing tank 2 (above the object to be processed), and water from the water supply channel 18 is supplied into the processing tank 2 through the watering nozzle 19. Is done. A water supply valve 20 (21) and a check valve 22 are provided in the water supply passage 18, and water supply into the treatment tank 2 can be controlled by the water supply valve 20 (21).

  It is preferable that the feed water flow rate through the feed water channel 18 is configured to be changeable. In the present embodiment, the feed water flow rate can be changed as follows. In other words, the first water supply valve 20 is provided in the water supply passage 18, and the front and rear of the first water supply valve 20 are connected by the bypass passage 23, and the second water supply valve 21 is provided in the bypass passage 23. The bypass passage 23 is formed by a pipe having a smaller diameter than the water supply passage 18. Accordingly, if the first water supply valve 20 (or both water supply valves 20, 21) is opened, water can be supplied at a relatively large flow rate, and if only the second water supply valve 21 is opened, water can be supplied at a relatively small flow rate. it can.

  In the present embodiment, the first water supply valve 20 is composed of an air drive valve, while the second water supply valve 21 is composed of an electromagnetic valve. Further, depending on the water supply source, a water supply pump is provided in the water supply path 18 upstream of the respective water supply valves 20 and 21, and the water supply pump is operated when the water supply valve 20 (21) is opened.

  The drainage means 5 discharges water from the treatment tank 2 through the drainage channel 24. The drainage channel 24 is connected to the bottom of the treatment tank 2, and a drainage valve 25 and a check valve 26 are provided. By opening the drain valve 25, the water in the treatment tank 2 can be discharged to the outside.

  The compressed air supply means 6 supplies compressed air into the treatment tank 2 through the compressed air passage 27 (28). In the present embodiment, the first compressed air passage 27 from the compressed air supply source is connected to the upper part of the processing tank 2 via the compressed air shutoff valve 29, the first compressed air valve 30 and the check valve 31. In addition, a second compressed air passage 28 is provided between the compressed air shut-off valve 29 and the first compressed air valve 30 in the first compressed air passage 27, and the second compressed air passage 28 is The steam supply passage 14 (the conduit on the treatment tank 2 side of the steam supply cutoff valve 16 and the steam supply valve 17) is connected via the second compressed air valve 32 and the check valve 33.

  The second compressed air passage 28 is formed by a pipe having a smaller diameter than the first compressed air passage 27. Therefore, the flow rate through the second compressed air passage 28 is set to be smaller than the flow rate through the first compressed air passage 27. With the compressed air shut-off valve 29 opened, the first compressed air valve 30 and / or the second compressed air valve 32 is opened, so that compressed air from the compressed air source is supplied into the processing tank 2 and the atmospheric pressure. The inside of the treatment tank 2 can be pressurized to a pressure exceeding. In the present embodiment, the first compressed air valve 30 is composed of an air drive valve, while the second compressed air valve 32 is composed of an electromagnetic valve.

  The exhaust means 7 discharges the gas from the inside of the processing tank 2 under a pressure exceeding the atmospheric pressure via the exhaust path 34. The exhaust path 34 is connected to the upper part of the processing tank 2 and is provided with an exhaust valve 35. In the illustrated example, the exhaust passage 34 is a common conduit with the first compressed air passage 27 (the conduit closer to the treatment tank 2 than the first compressed air valve 30 and the check valve 31) on the treatment tank 2 side. . If the exhaust valve 35 is opened while the inside of the processing tank 2 is at a pressure exceeding the atmospheric pressure, the gas in the processing tank 2 is discharged to the outside through the exhaust path 34, and the pressure in the processing tank 2 may be lowered. it can.

  The vacuum release means 8 introduces outside air into the treatment tank 2 under a pressure lower than atmospheric pressure via the air supply path 36. The air supply path 36 is connected to the upper part of the processing tank 2 and is provided with a vacuum release valve 37. In the illustrated example, the air supply path 36 includes a first compressed air path 27 (a pipe line closer to the processing tank 2 than the first compressed air valve 30 and the check valve 31) and an exhaust path 34 (exhaust valve) on the processing tank 2 side. 35) and a common pipe line on the processing tank 2 side. When the vacuum release valve 37 is opened while the inside of the processing tank 2 is at a pressure lower than the atmospheric pressure, outside air is introduced into the processing tank 2 through the air supply path 36 and the pressure in the processing tank 2 is reduced to atmospheric pressure. Can be returned.

  As indicated by a two-dot chain line in FIG. 1, the sterilizer 1 may further include a circulation means 38 as desired. The circulation means 38 is means for circulating the water in the treatment tank 2. In the illustrated example, the lower part and the upper part of the treatment tank 2 are connected by a circulation path 39, and a circulation pump 40 and a pump circulation valve 41 are provided in the circulation path 39. In the illustrated example, the upstream side of the circulation path 39 (the pipeline on the treatment tank 2 side relative to the circulation pump 40) is a common pipeline with the drainage path 24 upstream of the drainage valve 25.

  The control means is a controller (not shown) for controlling the means 3 to 8 based on the elapsed time in addition to the detection signals of the sensors 9 to 12. Specifically, the bleeder valve 13, the steam supply cutoff valve 16, the steam supply valve 17, the first water supply valve 20, the second water supply valve 21, the drain valve 25, the compressed air cutoff valve 29, the first compressed air valve 30, the first In addition to the two-compressed air valve 32, the exhaust valve 35, and the vacuum release valve 37, the pressure sensor 9, the temperature sensor 10, the product temperature sensor 11, the water level sensor 12, and the like are connected to a controller. When the sterilizer 1 includes the circulation means 38, the controller is further connected to the circulation pump 40 and the pump circulation valve 41. And a controller performs heat sterilization of the to-be-processed object in the processing tank 2, and subsequent cooling according to a predetermined | prescribed procedure (program) so that it may describe below.

  Typically, the sterilization apparatus 1 of the present embodiment sequentially executes a temperature raising process, a sterilization process, and a cooling process. During the operation of the sterilizer 1, the bleeder valve 13, the steam supply cutoff valve 16, the steam supply valve 17, the first water supply valve 20, the second water supply valve 21, the compressed air cutoff valve 29, among the above-described valves, The first compressed air valve 30 and the second compressed air valve 32 are closed, and the drain valve 25, the exhaust valve 35, and the vacuum release valve 37 are opened. Prior to the start of operation, an object to be processed is accommodated in the processing tank 2, and the door of the processing tank 2 is closed in an airtight manner. When the start of operation is instructed, for example, when a predetermined start button is pressed, the controller closes the drain valve 25, the exhaust valve 35, and the vacuum release valve 37, and starts a series of steps. Hereinafter, each step will be described.

≪Temperature raising process≫
In the temperature raising step, the temperature in the treatment tank 2 is raised to the sterilization temperature. For this purpose, the steam supply shutoff valve 16 and the steam supply valve 17 are opened to supply steam into the treatment tank 2. At this time, it is preferable to perform on / off control of the steam supply shutoff valve 16 so that the temperature in the processing tank 2 rises at a set speed. Specifically, the temperature in the processing tank 2 is raised to a predetermined value according to the elapsed time, but the steam supply shutoff valve 16 is turned on and off so that it falls within the range between the upper limit temperature and the lower limit temperature of the target temperature at each time point. It is preferable to control. That is, when the temperature exceeds the upper limit temperature, the steam supply shutoff valve 16 is closed, while when the temperature falls below the lower limit temperature, the steam supply shutoff valve 16 is opened. And the inside of the processing tank 2 is heated up to the sterilization temperature range by gradually raising the upper limit temperature and the lower limit temperature. While having the steam supply valve 17 whose opening degree can be adjusted, the fluid in the treatment tank 2 can be stirred as described later by darely controlling the steam supply shutoff valve 16 on and off.

  In the temperature raising step, it is preferable to reduce the opening of the steam supply valve 17 stepwise. To give specific examples, from the low temperature range at the start of operation to the high temperature range of the sterilization temperature, the low temperature range (less than the first switching temperature), the medium temperature range (above the first switching temperature and less than the second switching temperature) and the high temperature range ( The opening of the steam supply valve 17 is, for example, an opening degree of 100% (fully open) in the low temperature range, an opening degree of 60% in the intermediate temperature range, an opening degree of 40% in the high temperature range, for example. It is better to make it smaller step by step. Thereby, it can prevent that the temperature in the processing tank 2 goes over the sterilization temperature (overshoot), and can shift to a sterilization process smoothly. That is, the boundary temperature (second switching temperature) between the intermediate temperature range and the high temperature range is set to be lower than the sterilization temperature, and the opening degree of the steam supply valve 17 is relatively small in the high temperature range including the sterilization temperature. Since it is set, it is possible to easily shift to the sterilization process after the sterilization temperature is reached (maintained at the sterilization temperature).

  In the temperature raising step, as the inside of the treatment tank 2 is heated, the compressed air supply means 6 is preferably pressurized to a pressure exceeding the atmospheric pressure (higher than the saturated vapor pressure corresponding to the temperature inside the treatment tank). At this time, the supply of compressed air into the treatment tank 2 is preferably performed through the second compressed air passage 28 and the steam supply passage 14 by opening the second compressed air valve 32. By mixing the compressed air into the steam generated by the steam supply passage 14, the compressed air can be preheated and supplied into the treatment tank 2.

  In the temperature raising step, the second compressed air valve 32 and the exhaust valve 35 are controlled so that pressurization according to the temperature in the processing tank 2 is performed. Such pressurization in the treatment tank 2 is continued until the end of the cooling step even after the treatment tank 2 is raised to the sterilization temperature. Meanwhile, the compressed air shut-off valve 29 is maintained in an open state, and the opening and closing of the compressed air valve 30 (32) and the exhaust valve 35 are controlled.

≪Sterilization process≫
In the sterilization process, the temperature in the processing tank 2 is maintained at the sterilization temperature, and the object to be processed is heated and sterilized. Here, on / off control of the steam supply shutoff valve 16 is performed so that the temperature in the treatment tank 2 maintains the sterilization temperature. For example, regarding the sterilization temperature, an upper limit temperature and a lower limit temperature are set (that is, a sterilization temperature range is set), and when the temperature exceeds the upper limit temperature, the steam supply shutoff valve 16 is closed. 16 is opened and the inside of the treatment tank 2 is maintained in the sterilization temperature range. During this time, the opening degree of the steam supply valve 17 is maintained constant (the opening degree in the high temperature region of the temperature raising process).

  In the sterilization step, the fluid in the processing tank 2 can be stirred by switching the opening and closing of the steam supply shutoff valve 16 in a state where the opening of the steam supply valve 17 is fixed. Temperature unevenness can be prevented. In other words, if the sterilization temperature is maintained only by adjusting the opening degree of the proportional control valve, if the opening degree of the proportional control valve is continuously and minutely adjusted, the fluid in the treatment tank 2 can be agitated. However, the fluid in the processing tank 2 can be agitated by the steam jet when the steam supply shutoff valve 16 is opened by controlling on / off of the steam supply shutoff valve 16 as in this embodiment. .

  Further, in the sterilization step, an air flow may be generated in the processing tank 2 by opening the bleeder valve 13 and gradually letting the gas in the processing tank 2 to the outside. Also by this, the gas in the processing tank 2 can be flowed, and temperature nonuniformity can be prevented. The bleeder valve 13 can be opened not only in the sterilization process but also in the temperature raising process described above.

  When the inside of the treatment tank 2 is at or above the sterilization temperature and the sterilization time has elapsed, the steam supply shutoff valve 16 and the steam supply valve 17 are closed to stop the steaming into the treatment tank 2 and the sterilization process is terminated. In the sterilization process, the sterilization temperature may be changed stepwise. For example, after holding the first sterilization time at the first sterilization temperature, the temperature is raised (or lowered) to the second sterilization temperature higher (or lower) than the first sterilization temperature, and held at the second sterilization temperature. May be. The temperature increase in the processing tank 2 can be performed by the same operation as the above-described temperature increasing process, and the temperature decrease in the processing tank 2 can be performed by the same operation as the cooling process described later.

≪Cooling process≫
In the cooling process, water is supplied into the treatment tank 2 by the water supply means 4 to cool the object to be treated in the treatment tank 2. Immediately after the start of the cooling step, it is preferable to open the second water supply valve 21 and supply water into the treatment tank 2 at a relatively small flow rate so that the pressure and temperature in the treatment tank 2 do not drop rapidly. Thereafter, if the set condition is satisfied (for example, when a predetermined time elapses or the temperature, pressure, or water level in the processing tank 2 becomes predetermined), the first water supply valve 20 is used instead of (or in addition to) the second water supply valve 21. The water can be supplied at a relatively large flow rate. Similarly, immediately after the start of cooling, not the second compressed air valve 32 but the first compressed air valve 30 is opened, so that a rapid pressure drop in the processing tank 2 can be prevented. Also in this case, the control may be switched to the control of the second compressed air valve 32 thereafter.

  Water from the water supply path 18 is sprinkled from the sprinkling nozzle 19 in the upper part of the treatment tank 2 to the object to be treated, thereby cooling the object to be treated. As the cooling process, the following cooling operations are selected and can be performed. However, the second cooling operation and the third cooling operation can be performed when the sterilizer 1 includes the circulation means 38. Which cooling operation is performed is set in the controller in advance. In this setting, as shown in the following (a) to (c), any one of the cooling operations can be selected and set to be executable. In addition, as shown in the following (d), the cooling operations are combined. It can be set to be executable sequentially. That is, it is preferable that the controller can set which cooling operation is executed in which order among the first cooling operation, the second cooling operation, and the third cooling operation. Thus, for example, (1) the first cooling operation is performed after the second cooling operation is performed, (2) only the third cooling operation is performed, or (3) the third cooling operation is performed after the first cooling operation is performed. When the operation is performed a plurality of times, the cooling process can be executed with various contents.

  (A) In the first cooling operation, water is supplied into the treatment tank 2 by the water supply means 4 up to the water level at which the workpiece is immersed. Here, water is stored in the treatment tank 2 by the water supply means 4 until the object to be cooled is completely submerged. Then, after the set cooling time has elapsed, the water in the treatment tank 2 is discharged to the outside by the drainage means 5. When the circulation means 38 is provided, the circulation means 38 is preferably operated.

  (B) In the second cooling operation, water is circulated by the circulation means 38 for a set circulation time in a state where water is supplied into the treatment tank 2 by the water supply means 4 to a water level at which the workpiece is not immersed. By cooling the stored water at the bottom of the treatment tank 2 back to the treatment object by the circulation means 38, the treatment object can be cooled. Thereafter, water is discharged out of the treatment tank 2 by the drainage means 5. And preferably, such an operation (water supply into the treatment tank 2, circulation of stored water, set of drainage of stored water) is repeated a set number of times.

  (C) In the third cooling operation, water is circulated by the circulation means 38 in a state where water is supplied into the treatment tank 2 by the water supply means 4 to a water level at which the workpiece is not immersed. During the circulation, the water supply means 4 and the drainage means 5 are controlled, and the water in the treatment tank 2 is gradually replaced to cool the circulating water. At this time, the water supply valve 20 (21) and the drain valve 25 are intermittently opened and closed so that the temperature decreasing speed becomes the set speed, and the water supply flow rate into the treatment tank 2 and the waste water flow rate outside the treatment tank 2 are adjusted. It is preferable to adjust. In addition, it is preferable that the water supply into the processing tank 2 is performed at a relatively small flow rate by opening the second water supply valve 21. Alternatively, the drain valve 25 may be intermittently controlled to open and close while the second water supply valve 21 is kept open and water is continuously supplied into the treatment tank 2 at a relatively small flow rate.

  (D) You may combine each cooling operation, such as combining the 2nd cooling operation and 3rd cooling operation which were mentioned above (for example, performing a 3rd cooling operation after performing a 2nd cooling operation in multiple times).

  In any case, when the cooling process is performed for a predetermined time or when the temperature in the processing tank 2 or the product temperature of the object to be cooled falls to the predetermined temperature, the water supply to the processing tank 2 is stopped and the drainage means 5 Thus, the water in the treatment tank 2 is discharged, and the cooling process is completed. At this time, pressurization in the processing tank 2 by the compressed air supply means 6 is also stopped. Then, after opening the exhaust valve 35 and releasing the pressurization in the processing tank 2, the vacuum release valve 37 is further opened to make sure that the inside of the processing tank 2 is at atmospheric pressure. Thereby, the door of the processing tank 2 can be opened and an object to be processed can be taken out from the processing tank 2.

  By the way, in the first cooling operation, water is stored in the processing tank 2 to a predetermined full water level, and the object to be processed is cooled in a state where the object to be processed is submerged. At this time, when the sterilizer 1 includes the circulation means 38, it is preferable to operate the circulation means 38 as described above. However, the start of the operation of the circulation means 38 does not necessarily have to wait until the full water level. That is, during the water supply to the processing tank 2 by the water supply means 4, the circulating means 38 may be operated when the stored water in the processing tank 2 becomes higher than the set water level or the temperature of the stored water becomes lower than the set temperature. .

  Even when the water supply means 4 supplies water into the treatment tank 2 and before the final water level is reached, if the stored water in the treatment tank 2 becomes higher than the set water level or the temperature of the stored water becomes lower than the set temperature, the circulation By operating the means 38, rapid cooling can be achieved. Moreover, if the circulation by the circulation means 38 is started on the condition that the temperature of the stored water is lower than the set temperature (for example, 80 ° C.) or higher than the water level at which such temperature is reached, the circulation pump having a high heat resistance temperature. 40 (that is, the standard circulation pump 40 can be used instead of the hot water specification), and the cooling system of the circulation pump 40 (cooling configuration of the mechanical seal portion) can be dispensed with.

  When the circulation by the circulating means 38 is started on the condition that the stored water in the treatment tank 2 becomes equal to or higher than the set water level, the set water level is set in accordance with the amount of work to be processed in the treatment tank 2. It may be changeable. Specifically, the input weight of the object to be processed into the processing tank 2 may be measured with a load cell or the like, and the set water level for starting circulation may be changed based on the measured weight. If there is little quantity of a to-be-processed object, the circulation will be started from a comparatively low water level, and cooling according to a processing amount will be attained. Further, the final full water level may be changeable in accordance with the amount of work to be processed into the treatment tank 2.

  The sterilization apparatus 1 of the present invention is not limited to the configuration (including control) of the above embodiment, and can be changed as appropriate. In particular, (a) a treatment tank 2 in which the object to be treated is accommodated, a steam supply means 3 for supplying steam to the treatment tank 2 to heat the object to be treated, and a control means for controlling the steam supply means 3 (B) The steam supply means 3 includes a steam supply shut-off valve 16 that switches on / off the presence / absence of steam supply to the steam supply path 14 into the treatment tank 2, and a steam supply valve 17 whose opening degree can be adjusted. (C) In the sterilization step of heating the object to be processed, the other configuration is appropriately determined if the opening / closing of the steam supply shutoff valve 16 is switched with the opening degree of the steam supply valve 17 fixed. It can be changed.

DESCRIPTION OF SYMBOLS 1 Sterilizer 2 Processing tank 3 Steam supply means 4 Water supply means 5 Drainage means 6 Compressed air supply means 7 Exhaust means 8 Vacuum release means 9 Pressure sensor 10 Temperature sensor 11 Product temperature sensor 12 Water level sensor 13 Breeder valve 14 Steam supply path 15 Supply Steam nozzle 16 Steam supply shutoff valve 17 Steam supply valve 18 Water supply path 19 Water spray nozzle 20 First water supply valve 21 Second water supply valve 22 Check valve 23 Bypass path 24 Drainage path 25 Drainage valve 26 Check valve 27 First compressed air path 28 Second compressed air passage 29 Compressed air shut-off valve 30 First compressed air valve 31 Check valve 32 Second compressed air valve 33 Check valve 34 Exhaust passage 35 Exhaust valve 36 Supply air passage 37 Vacuum release valve 38 Circulating means 39 Circulation Path 40 Circulation pump 41 Pump circulation valve

Claims (5)

A treatment tank in which the object to be treated is stored, steam supply means for supplying steam into the treatment tank to heat the object to be treated, and control means for controlling the steam supply means,
The steaming means includes a steaming shutoff valve that switches on / off the presence or absence of steaming in a steaming path into the treatment tank, and a steaming valve whose opening degree can be adjusted in series.
In the sterilization step of heating the object to be treated, the sterilization apparatus is configured to switch between opening and closing of the steam supply shutoff valve in a state where the opening of the steam supply valve is fixed. A temperature raising step for raising the inside of the treatment tank to the sterilization temperature, and a sterilization step for keeping the inside of the treatment tank at the sterilization temperature are sequentially performed.
The sterilizer according to claim 1, wherein in the temperature raising step, the opening degree of the steam supply valve is reduced stepwise. Water supply means into the treatment tank, and drainage means to the outside of the treatment tank,
In the cooling step after the sterilization step, water is stored in the treatment tank by the water supply means up to a water level in which the treatment object is immersed with the steam supply shut-off valve closed, and the treatment object is cooled. The sterilizing apparatus according to claim 1 or 2, wherein: Circulating means for injecting water from the bottom in the treatment tank back to the object to be treated in the treatment tank is further provided.
During the water supply to the treatment tank by the water supply means, the circulating means is activated when the stored water in the treatment tank is equal to or higher than a set water level or the temperature of the stored water is equal to or lower than a set temperature. The sterilizer according to claim 3. In the cooling step, instead of storing water in the treatment tank up to a water level where the treatment object is immersed, water is stored in the treatment tank up to a water level where the treatment object is not immersed, and the storage is performed. The sterilization apparatus according to claim 4, wherein the processing object is cooled by spraying water back to the processing object by the circulation means.

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