JP4721142B2 - Steam sterilizer - Google Patents

Description

  The present invention relates to a steam sterilization apparatus that performs a steam sterilization process on an object to be sterilized in a sterilization tank.

  In general, sterilization using a steam sterilizer is performed by the following steps. That is, an air evacuation step in which an object to be sterilized is housed in a sterilization tank and the air in the sterilization tank is excluded by a decompression means, a sterilization process in which steam is introduced into the sterilization tank and sterilization is performed, and the decompression means The sterilization operation is performed by a drying step of operating the sterilization object by operating and a return pressure step of returning the inside of the sterilization tank to atmospheric pressure.

  In such a conventional method, when an object to be sterilized composed of a moisture permeable waterproof material is covered with a sterilization bag for packaging (sterilization bag), the object to be sterilized is inflated by rapid decompression, and sterilized. The bag ruptured, causing a problem that bacteria were attached to the object to be sterilized to cause damage.

  As a result of pursuing the cause, the inventors of this application have difficulty in passing the air and steam through the sterilized object, so that the exhaust speed is combined and the expansion is excessive during decompression and the sterilization bag is ruptured. I got the knowledge that it would occur.

JP 2000-199490 A

  The problem to be solved by the present invention is to prevent the sterilization bag from bursting.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The invention according to claim 1 is a sterilization tank for containing an object to be sterilized wrapped in a sterilization bag and containing a moisture permeable waterproof material, Steam supply means for supplying steam for sterilization to the tank, exhaust means for reducing the pressure in the sterilization tank and exhausting the gas in the sterilization tank, return pressure means for returning the pressure in the sterilization tank, and the steam supply Means, controlling the exhaust means and the decompression means to exhaust the air in the sterilization tank, exhausting the air into the sterilization tank, sterilizing the object to be sterilized by steaming, and drying the object to be sterilized In a steam sterilizer equipped with a control means for sequentially performing the drying process,
The exhaust means includes an exhaust speed adjusting means provided with a resistance adjusting member, and is configured to be adjustable to a high exhaust speed and a low exhaust speed at which the reduced pressure exhaust speed is adjusted by the resistance adjusting member. , By repeating the vacuum exhaust in the sterilization tank and steaming into the sterilization tank, the air exclusion step,
In this air exclusion process, when an object to be sterilized containing a moisture permeable waterproof material is accommodated in the sterilization tank, the exhaust means is decompressed and exhausted at the high speed exhaust speed at the time of the first decompression exhaust process, and then the decompression is performed. The exhaust process is characterized in that an adjustment process for reducing the exhaust speed is performed.

According to the first aspect of the present invention, in addition to the effect of preventing the sterilization bag packaging the article to be sterilized in the air exclusion step, the effect of shortening the sterilization operation time can be achieved.

The invention according to claim 2 is a sterilization tank for containing an object to be sterilized wrapped in a sterilization bag and containing a moisture permeable waterproof material, steam supply means for supplying sterilization steam to the sterilization tank, and the sterilization An exhaust means for exhausting the gas in the sterilization tank by depressurizing the inside of the tank, a return pressure means for returning the pressure in the sterilization tank, a steam supply means, the exhaust means, and the return pressure means, and controlling the sterilization In a steam sterilization apparatus comprising an air evacuation process for discharging air in a tank, a sterilization process for steaming into the sterilization tank to sterilize an object to be sterilized, and a control means for sequentially performing a drying process for drying the object to be sterilized,
The exhaust means includes an exhaust speed adjusting means provided with a resistance adjusting member, and is configured to be adjustable to a high exhaust speed and a low exhaust speed at which the reduced pressure exhaust speed is adjusted by the resistance adjusting member. The drying step is repeated by repeating depressurization exhausting the atmospheric pressure below the atmospheric pressure in the sterilization tank and returning pressure by introducing the external air inside the sterilization tank, or introducing the external air while reducing the pressure inside the sterilization tank below the atmospheric pressure. Done
In this drying process, when an object to be sterilized containing a moisture-permeable and waterproof material is accommodated in the sterilization tank, the exhaust means is adjusted to the low exhaust speed for the vacuum exhaust process two to three times from the start of the drying process. The process is performed, and the subsequent evacuation process is characterized by evacuating at the high exhaust speed.

According to invention of Claim 2, in addition to the effect which prevents the burst of the sterilization bag which packages the said to-be-sterilized thing in the said drying process , there exists an effect that sterilization operation time can be shortened.

  According to this invention, the sterilization bag can be prevented from bursting in the air exclusion step or the drying step.

(Embodiment of the apparatus)
Next, an embodiment of the apparatus of the present invention will be described. An embodiment of the device of the present invention is implemented in a steam sterilizer.

  An embodiment of the apparatus of the present invention comprises a sterilization tank for containing an object to be sterilized wrapped in a sterilization bag and containing a moisture-permeable waterproof material, steam supply means for supplying sterilization steam to the sterilization tank, Controlling the exhaust means for reducing the pressure in the sterilization tank and exhausting the gas in the sterilization tank, the return pressure means for returning the pressure in the sterilization tank, the steam supply means, the exhaust means, and the return pressure means, An air exhausting process for exhausting air in the sterilization tank by repeatedly performing vacuum exhaust in the sterilization tank and steaming in the sterilization tank, a sterilization process for steaming into the sterilization tank and sterilizing an object to be sterilized, and In a steam sterilization apparatus comprising: a control means for sequentially performing a drying process for drying an object to be sterilized by repeatedly performing a vacuum exhaust in the sterilization tank below the atmospheric pressure and a return pressure by introducing outside air in the sterilization tank; Decompression pumping speed adjusted to high pumping speed and low pumping speed And in the air evacuation step and the drying step, when the sterilized material containing the moisture permeable and waterproof material is accommodated in the sterilization tank, an adjustment step is performed for setting the exhaust means to a low exhaust speed. This is a steam sterilizer characterized by this. Here, “adjustable to high exhaust speed and low exhaust speed” includes adjusting not only in two stages but also in multiple stages or continuously.

  In an embodiment of this apparatus, first, after storing an object to be sterilized in the sterilization tank, the sterilization tank is sealed, and the sterilization tank is operated by depressurizing means, and the sterilization tank is evacuated and supplied. By repeating the steam supply into the sterilization tank by operating the steaming means, an air exhausting step of discharging the air in the sterilization tank to the outside of the tank is performed. Next, a sterilization process is performed in which the steam supply means is operated to supply steam (steaming) into the sterilization tank to sterilize the object to be sterilized. When the sterilization step is completed, the decompression means is operated to reduce the pressure inside the sterilization tank to a pressure lower than the atmospheric pressure, and the decompression means is operated to return the external pressure into the sterilization tank by reintroduction. A drying step is performed to dry the object to be sterilized. In this embodiment, in the air exclusion step and the drying step, by performing an adjustment step of slowing down the exhaust speed by the decompression means, the expansion of the sterilized material can be suppressed, and the expansion of the sterilized material Rupture of the sterilization bag is prevented.

Here, each component in the embodiment of the apparatus will be described. In the following description, the steam is saturated steam, but is not limited to this, and includes steam mixed with air.

  Preferably, the sterilized material is entirely made of a moisture-permeable and waterproof material, but only a part thereof can be made of a moisture-permeable and waterproof material. In addition, the sterilized product is sterilized by being covered with a well-known moisture-permeable sterilization bag for packaging in order to perform sterilization and drying more reliably and to maintain a sterilized state after sterilization for a longer time. This sterilization bag can be referred to as a packaging member.

  The moisture-permeable and waterproof material means a material having a property of allowing gas (vapor) to pass but not liquid (water). And this moisture-permeable waterproof material has the property that gas cannot pass easily. As such a moisture-permeable and waterproof material, a material having many very small holes or a material in which such a microporous film is bonded to a cloth can be used. Alternatively, a non-porous material that does not allow water droplets to pass therethrough but allows water vapor to move, or a coating-type material that performs a strong water-repellent treatment on a high-density fabric can also be used. As such a moisture-permeable and waterproof material, GORE-TEX (registered trademark) is preferably used, but is not limited thereto.

  Here, the reason why the moisture-permeable and waterproof material expands will be described. In the case of moisture-permeable and waterproof material that is difficult to pass gas, when the process of putting steam into the decompression process with steam condensed on the surface or inside, the condensed water boils inside, the volume expands, and the pressure rises . Thus, in the moisture permeable waterproof material, a pressure difference between the inside and the outside is likely to occur, so that a larger pressure difference is generated and expansion is increased.

  The sterilization tank is not limited to a specific structure as long as the sterilization tank has an opening for taking in and out an object to be sterilized and a door for opening and closing the opening. This sterilization tank can be referred to as a sterilization container, a sterilization region, a sterilization chamber, or the like. The sterilization tank is preferably configured to heat the tank wall by a jacket or a pipe to which steam is supplied.

  The steam supply means includes a steam supply line having one end connected to the sterilization tank and the other end connected to a steam generation source such as a boiler, and a steam supply valve provided in the steam supply line. The steam supply valve is an electromagnetic valve that is only opened and closed, but may be an opening degree adjusting valve such as a proportional valve or a motor valve whose opening degree can be adjusted. The steam generation source preferably heats pure water to obtain clean steam.

  The exhaust means has a function of exhausting the inside of the sterilization tank under reduced pressure, and includes an exhaust speed adjusting means. Preferably, the exhaust speed adjusting means is connected in parallel to the decompression line having one end connected to the sterilization tank and the other end opened to the atmosphere, a first valve and a decompressor provided in the sterilization line, and the first valve. And a second valve provided in the bypass line. The flow resistance of the bypass line is adjusted by adjusting the opening of the second valve, reducing the diameter of the bypass line, or providing a resistance adjusting member such as an orifice in the bypass line. . As a result, the first valve is opened and the second valve is closed (may be left open) to increase the exhaust speed, and the first valve is closed and the second valve is opened to reduce the low exhaust speed. Realize.

  The low evacuation speed is set to a value that prevents the sterilized bag from rupturing and rupturing the packaging sterilization bag when decompressed exhaust is performed in the air exclusion step and the drying step. This setting can be obtained in advance by experiments. A check valve for preventing a flow from the outside of the sterilization tank to the inside of the sterilization tank can be provided in the decompression line and the bypass line.

As the exhaust speed adjusting means, the bypass line may not be provided. That is, using the first valve as an adjustment valve whose flow resistance can be adjusted, the low exhaust speed is obtained by reducing the opening degree of the first valve in the adjustment step, and the opening degree is increased in the non-adjustment step. Thus, the high exhaust speed is obtained.

  The decompressor is preferably a vacuum pump, but can be a water ejector. The decompressor may be configured to have a heat exchanger for condensing steam on the upstream side of the vacuum pump or water ejector, and further configured to provide a steam ejector on the upstream side of the heat exchanger for condensing. can do.

  The return pressure means includes a return pressure line connected to the sterilization tank and a return pressure valve provided in the return pressure line. The return pressure valve is an electromagnetic valve that is only opened and closed, but can be an opening degree adjusting valve such as a proportional valve or a motor valve whose opening degree can be adjusted. The return pressure line may be provided with a check valve that prevents the flow from the inside of the sterilization tank to the outside of the sterilization tank.

  The control means inputs a signal from a pressure sensor for detecting the pressure in the sterilization tank based on a sterilization program (control procedure) stored in advance, and the steam supply means, the pressure reducing means, and the pressure-reducing means are It is configured to execute the air exclusion process, the sterilization process, the drying process and the like under control.

  The air exclusion process is performed by repeating a reduced pressure exhaust process and a steam supply process. The depressurizing and exhausting step is executed until the detected value by the pressure sensor becomes a first set value lower than the atmospheric pressure by operating the depressurizer, and the steaming step operates the steaming means. Thus, the process is executed until the detection value by the pressure sensor becomes a set value equal to or higher than the atmospheric pressure. The number of repetitions is two or more, and is obtained by experiments in advance.

  In this air exclusion step, the control means controls the exhaust speed adjusting means to control the exhaust speed to be the low exhaust speed when an object to be sterilized containing a moisture permeable waterproof material is accommodated in the sterilization tank. The exhaust speed adjustment process is performed. The adjustment of the exhaust speed is preferably performed when the sterilization bag is wet by a predetermined amount or more.

  The reason is that in the state where the vapor penetrates into the sterilization bag (wet state), if the exhaust speed is increased, the article to be sterilized expands and ruptures the packaging member. Then, the exhaust speed is decreased, and the exhaust speed is not decreased in the decompression exhaust process that is not wet. In this embodiment, at the time of the first decompression exhaust process of the air exclusion process, it is not steamed yet and is not in the wet state, so the exhaust is decompressed at the high exhaust rate, and in the subsequent decompression exhaust process, Evacuate at low exhaust speed. In the initial stage of this air exclusion process, it is determined by experiment whether the decompression process for setting the high exhaust speed is only performed first or the number of times including the next is performed.

  Thus, the total number of sterilization operations can be shortened by limiting the number of times of the low pressure exhaust pressure decompression process in the air exclusion process.

  The sterilization step is performed by supplying steam into the sterilization tank. This steaming is performed so that the temperature in the sterilization tank detected by the pressure sensor is maintained at a temperature suitable for sterilization (second set value) for a predetermined time by operating the steaming means.

The drying process is performed by repeating a reduced pressure exhaust process and a return pressure process. The depressurizing and exhausting step is executed until the pressure in the sterilization tank detected by the pressure sensor is set to be equal to or lower than the atmospheric pressure by operating the depressurizer. By operating the means, it is executed until the pressure detected by the pressure sensor reaches atmospheric pressure. The number of repetitions is set to be greater than that of the air exclusion step and is determined in advance by experiment.

  The first depressurization step performed at the time of transition from the sterilization step to the drying step is preferably connected to the sterilization tank without operating the depressurization means until the inside of the sterilization tank reaches atmospheric pressure. Exhaust is performed by another exhaust line, and the decompression means is activated when atmospheric pressure is reached. With such a configuration, the steam can be effectively discharged. Of course, without providing the exhaust line, the decompression means can be operated from the beginning to discharge the steam. The discharge of steam through the exhaust line can be referred to as an exhaust process, and can be a separate process from the drying process.

  Also in this drying step, the control means controls the exhaust speed adjusting means to control the exhaust speed when the material to be sterilized including the moisture permeable waterproof material is accommodated in the sterilization tank, thereby reducing the exhaust speed. A pumping speed adjustment step is performed to set the speed. The adjustment of the exhaust speed is also preferably performed when the sterilization bag is wet by a predetermined amount or more.

  In this embodiment, since the wet state is improved by repeating the vacuum exhausting process an appropriate number of times, the vacuum exhausting process is performed at a low exhausting speed two to three times from the start of the drying process, and thereafter In the decompression / exhaust step, decompression is performed at the high exhaust rate. In the initial stage of the drying process, the number of times of the pressure reducing process for reducing the exhaust speed is determined by experiments.

  Thus, the total number of sterilization work times can be shortened by limiting the number of times of the vacuum exhausting step at the low exhausting speed in the drying step.

  The present invention is not limited to the embodiment of the apparatus. For example, the embodiment of the apparatus is configured to perform the adjustment step in the air exclusion step and the drying step, but the vacuum exhausting step is repeated in either the air exclusion step or the drying step. In the case of employing an air exclusion process or a drying process that is not performed, the adjustment process can be performed only in the air exclusion process or the drying process in which the vacuum exhaust process is repeatedly performed. Further, the drying step can be configured not to be performed by repeating the reduced pressure exhausting step and the return pressure step, but also by a method of introducing outside air while reducing the pressure. In this case, expansion of the article to be sterilized is suppressed by reducing the pressure reduction speed at the initial stage of pressure reduction.

(Method Embodiment)
Next, Embodiments 1 to 4 of the method realized by the embodiments of the apparatus will be described.

  First, Embodiment 1 of the method is an air exclusion step for discharging air in the sterilization tank containing a material to be sterilized wrapped in a sterilization bag and containing a moisture-permeable waterproof material, and steaming into the sterilization tank In a steam sterilization method that sequentially performs a sterilization process for sterilizing an object to be sterilized and a drying process for drying the object to be sterilized, the reduced pressure exhaust speed of the sterilization tank can be adjusted to a high exhaust speed and a low exhaust speed, and the sterilization The air evacuation process is repeated by repeating the vacuum exhaust in the tank and the steaming into the sterilization tank, and in this air evacuation process, an object to be sterilized including a moisture-permeable and waterproof material is accommodated in the sterilization tank. The steam sterilization method is characterized in that an adjustment step of setting the reduced pressure exhaust speed to the low exhaust speed is performed.

  According to Embodiment 1 of this method, the sterilization bag can be prevented from bursting in the air exclusion step.

In the second embodiment of the method, the air evacuation step of discharging the air in the sterilization tank containing the material to be sterilized wrapped in a sterilization bag and containing a moisture permeable waterproof material, steaming into the sterilization tank In a steam sterilization method that sequentially performs a sterilization process for sterilizing an object to be sterilized and a drying process for drying the object to be sterilized, an air exhausting process for discharging air in the sterilization tank, and steaming the sterilization tank to supply the object to be sterilized In a steam sterilization method in which a sterilization step for sterilization and a drying step for drying an object to be sterilized are sequentially performed, the vacuum exhaust speed of the sterilization tank can be adjusted to a high exhaust speed and a low exhaust speed, and The drying step is performed by repeating the decompression exhaust under the atmospheric pressure and the return pressure due to the introduction of the outside air in the sterilization tank, or by introducing the outside air while reducing the inside of the sterilization tank to the atmospheric pressure or less. ,in front A steam sterilization wherein the adjusting step of the vacuum pumping speed and the low pumping speed.

  According to Embodiment 2 of this method, the sterilization bag can be prevented from bursting in the drying step.

  Further, Embodiment 3 of the method is an air exhausting process for discharging air in the sterilization tank containing a material to be sterilized wrapped in a sterilization bag and containing a moisture-permeable waterproof material, and steaming into the sterilization tank In a steam sterilization method that sequentially performs a sterilization process for sterilizing an object to be sterilized and a drying process for drying the object to be sterilized, the reduced pressure exhaust speed of the sterilization tank can be adjusted to a high exhaust speed and a low exhaust speed, and the sterilization The vacuum exhaust in the tank and the steam supply to the sterilization tank are repeated to perform the air exclusion step, and the vacuum exhaust below the atmospheric pressure in the sterilization tank and the return pressure by introducing the outside air in the sterilization tank are repeated. Alternatively, the drying step is performed by introducing outside air while reducing the inside of the sterilization tank below atmospheric pressure. In the air exclusion step and the drying step, an object to be sterilized including a moisture-permeable waterproof material is sterilized. Fit in the tank When a steam sterilization wherein the adjusting step of said vacuum pumping speed the low pumping speed.

  According to Embodiment 3 of this method, the sterilization bag can be prevented from rupturing in the air exclusion step and the drying step.

  Further, the fourth embodiment of the method is characterized in that, in the first to third embodiments of the method, the adjustment step is performed in a part of the step, that is, the air exclusion step and / or the drying step. Sterilization method.

  According to Embodiment 4 of this method, the sterilization operation (sterilization operation) time from the air exclusion process to the drying process can be shortened.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. First, a first embodiment of a steam sterilizer to which the present invention is applied will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of the first embodiment, and FIG. 2 is a diagram illustrating a pressure change in the sterilization tank 2 due to a sterilization operation. In FIG. 2, the solid line indicates a conventional example in which the reduced pressure exhaust speed is not adjusted, and the broken line indicates the first embodiment.

  The steam sterilization apparatus shown in FIG. 1 includes a sterilization tank 2 for storing an object 1 to be sterilized, steam supply means 3 for supplying sterilization steam to the sterilization tank 2, and the sterilization tank 2 by depressurizing the sterilization tank. First exhaust means 4 for exhausting the gas in the tank 2, return pressure means 5 for returning the pressure in the sterilization tank 2 to atmospheric pressure, the steam supply means 3, the first exhaust means 4 and the return pressure means 5 The main part is provided with a controller 6 as a control means for controlling the steam supply means 3, the first exhaust means 4 and the return pressure means 5 to execute a sterilization program.

The sterilization program is a program for sequentially performing a preparation process, a preheating process, an air exclusion process, a sterilization process, and a drying process when the apparatus is cold-started. The air exclusion step is a step of discharging air in the sterilization tank 1, the sterilization step is a step of sterilizing an object to be sterilized by steaming into the sterilization tank 1, and the drying step is performed. This is a step of drying the sterilized product 1.

  Here, each component of the steam sterilizer will be described. The object to be sterilized 1 is an object to be sterilized made of a moisture-permeable and waterproof material, and is entirely covered (packed) with a bag 7 as a sterilization bag for packaging and sterilized. Gore-Tex (registered trademark) is used as the moisture-permeable and waterproof material.

  The bag 7 is composed of paper on one side and a transparent film on the other side, and is provided with an opening (not shown) that allows the article to be sterilized 1 to be taken in and out and sealed. In this embodiment, the bag 7 employs a sterilization bag (made by Hogi), but is not limited thereto.

  The sterilization tank 2 has an opening (not shown) through which the article to be sterilized 1 is put in and out, and a door (not shown) that opens and closes the opening so as to be able to be sealed. Further, the sterilization tank 2 has a well-known jacket structure, and is configured to heat or keep the sterilization tank 2 wall and the object to be sterilized 1 contained therein by introducing steam into the jacket. is doing.

  The steam supply means 3 has one end connected to the sterilization tank 2 and the other end connected to a reboiler (not shown) for generating clean steam, and a steam supply valve provided in the steam supply line 8. 9. The steam supply valve 9 is an opening adjustment valve whose opening can be adjusted.

  The first exhaust means 4 has a function of exhausting the inside of the sterilization tank 2 under reduced pressure, and includes exhaust speed adjusting means for adjusting the reduced pressure exhaust speed. This exhaust speed adjusting means includes a decompression line 10 having one end connected to the sterilization tank 2 and the other end open to the atmosphere, a first valve 11 provided in series in the sterilization line 10 and a water seal type as a decompressor. The vacuum pump 12 includes a bypass line 13 connected in parallel with the first valve 11 and a second valve 14 provided in the bypass line 13. The flow resistance of the bypass line 13 is set in advance by adjusting the opening of the second valve 14. That is, the first valve 11 is opened and the second valve 14 is closed, so that the high exhaust speed A (for example, 120 to 180 kPa / min) is established, the first valve 11 is closed, and the second valve 14 is opened. Thus, a low pumping speed B (for example, 60 to 80 kPa / min) is obtained.

  The low exhaust speed is set to such a value that the sterilized material expands and does not rupture the bag 7 when vacuum exhaust is performed in the air exclusion process and the drying process. The setting of the low exhaust speed is determined in advance by experiments. The decompression line 10 and the bypass line 13 are provided with a check valve (not shown) for preventing the flow from the outside of the sterilization tank 2 to the inside of the sterilization tank 2.

  The sterilization tank 2 is provided with a second exhaust means 15. The second exhaust means 15 includes an exhaust line 16 having one end connected to the bottom of the sterilization tank 2 and the other end connected to the decompression line 10, and a third valve 17 provided in the exhaust line 16. Is done. The exhaust line 16 functions as a steam discharge line for discharging the high-pressure steam and drain in the sterilization tank 2 to the outside of the tank after the sterilization step.

  The return pressure means 5 includes a return pressure line 18 connected to the sterilization tank 2, a return pressure valve 19 provided in the return pressure line 18, a sterilization filter 20, and the inside of the sterilization tank 2 to the outside of the sterilization tank 2. And a check valve 21 for preventing the flow of the gas.

The controller 6 inputs a signal from a pressure sensor 22 for detecting the pressure in the sterilization tank 2 based on the sterilization program, and supplies the steam supply means 3, the first exhaust means 4 and the return pressure means. 5 is executed to execute the air exclusion process, the sterilization process, the drying process, and the like.

  The air exclusion process is performed by repeating a reduced pressure exhaust process and a steam supply process. In the depressurizing and evacuating step, the first valve 11 is opened, the second valve 14 is closed, and the vacuum pump 12 is operated, so that a detected value by the pressure sensor is a first set value P1 (lower than atmospheric pressure) ( As an example, the process is executed until 50 kPa). In the steaming step, the first valve 11 and the second valve 14 are closed and the steaming means 3 is operated to steam into the sterilization tank 2, and the detected value by the pressure sensor 22 is It is executed until atmospheric pressure is reached. The number of repetitions is 3 in this embodiment.

  In this air evacuation step, the controller 6 controls the exhaust speed adjustment means, that is, exhausts the first valve 11 and the second valve 14 closed to set the exhaust speed to the low exhaust speed B. The speed adjustment process is performed. This adjustment process is performed when the inside of the bag 7 is wet. Specifically, in the first decompression exhaust step of the air exclusion step, decompression exhaust is performed at the high exhaust rate A, and the second and third decompression exhaust steps are decompressed at the low exhaust rate B. It is configured to do.

  The sterilization step is performed by supplying steam into the sterilization tank 2. In this steam supply, by operating the steam supply means 3, the pressure in the sterilization tank 2 detected by the pressure sensor 22 is maintained at a pressure suitable for sterilization (second set value P2) for a predetermined time. To be done.

  The drying process is performed by repeating a reduced pressure exhaust process and a return pressure process. In the reduced pressure exhaust process, as in the air exhaust process, the first valve 11 is opened and the second valve 14 is closed at a high exhaust speed, and the first valve 11 is closed at a low exhaust speed, and the second valve 14 is closed. This is done by opening the valve 14 and operating the vacuum pump 12. This pressure reduction is executed until the pressure in the sterilization tank 2 detected by the pressure sensor 22 reaches a set value lower than the atmospheric pressure (in the first embodiment, the first set value P1). The return pressure step is executed until the pressure detected by the pressure sensor 22 reaches atmospheric pressure by operating the return pressure means 5. The number of repetitions is set to 2 in this embodiment.

  In the first vacuum exhausting step performed at the time of transition from the sterilization step to the drying step, exhaust is performed using the second exhaust unit until the atmospheric pressure is reached, and when the atmospheric pressure is reached, exhaust is performed using the first exhaust unit 4. It is configured as follows.

  And also in this drying process, the said controller 6 controls the said exhaust speed adjustment means, and performs the exhaust speed adjustment process which makes an exhaust speed the said low exhaust speed B. FIG. The adjustment of the exhaust speed is also performed when the bag 7 is wet by a predetermined amount or more. In this embodiment, the vacuum exhaust process is performed at the low exhaust speed B three times from the start of the drying process, and the subsequent vacuum exhaust process is configured to perform the vacuum exhaust at the high exhaust speed B.

  The operation of the first embodiment having the above configuration will be described. After carrying in the sterilization tank 2 the article to be sterilized 1 which is entirely packaged in the bag 7, sterilization work (sterilization operation) is performed according to the following steps.

(Preparation process)
First, since the sterilization tank 2 itself is cold at the time of cold start or the like, the sterilization tank 1 itself is preheated as a preparation step. That is, the sterilization tank 1 is preheated by steaming the jacket through the steaming line 7 and a steaming line (not shown) for normal steam.

(Preheating process)
Next, in the preheating step, the object to be sterilized 1 in the sterilization tank 2 is heated to a predetermined temperature. That is, after the object to be sterilized is accommodated in the sterilization tank 2, the object to be sterilized in the sterilization tank 2 is preheated by steaming the jacket in the same manner as in the preparation step. Then, when the article to be sterilized is heated to a predetermined temperature, this preheating process is terminated, and then the air exclusion process is executed. This preheating step can be omitted.

(Air exclusion process)
In the air exclusion process, as shown in FIG. 2, the set of the vacuum exhaust process and the steam supply process is repeated three times. In the first decompression and evacuation step, the third valve 17 is opened, the first valve 11 is opened, the second valve 14 is closed, the vacuum pump 12 is operated, and the high pumping speed A is reached. Then, the air in the sterilization tank 2 is discharged from the decompression line 10. This decompression exhaust process is performed until the detected value by the pressure sensor 22 reaches the first set value P1 lower than the atmospheric pressure.

  In this first decompression exhaust process, the steam supply process has not yet been performed, so the inside of the bag 7 is not in a wet state due to steam. There is little expansion and the bag 7 is not ruptured.

  Subsequently, a steaming process is performed. In this steaming process, the first valve 11, the second valve 14 and the third valve 17 are closed, the steaming valve 9 is opened for a short time, and the steaming process is performed from the steaming line 8 to the sterilization tank. This is done by introducing clean steam into 2. This steaming process is performed until the pressure detected by the pressure sensor 22 reaches atmospheric pressure.

  In the second decompression exhaust process, the adjustment process is performed. That is, the first valve 11 is closed, the second valve 14 is opened, and the vacuum pump 12 is operated. Then, the gas in the sterilization tank 2 is exhausted under reduced pressure through the bypass line 13 having a large flow resistance. As a result, exhaust is performed at the low exhaust speed B. In this state, as shown by the broken line in FIG. 2, the pressure drop is gradual.

  As described above, since the low pressure exhaust speed B is used to reduce the pressure, the expansion of the article to be sterilized 1 is suppressed even when the bag 7 is in a wet state, and the bag 7 can be prevented from being ruptured.

  Next, after the steaming process is performed in the same manner, a third vacuum exhaust process is performed. In the decompression exhaust process, the adjustment process is performed as in the second time, and exhaust at the low exhaust speed is performed.

  As described above, the time required for the air removal process can be shortened by making the adjustment process a part of the air removal process, that is, by limiting the number of times of decompression exhausting at the low exhaust speed B. . As a result, the sterilization time can be shortened.

(Sterilization process)
After sufficiently removing the air in the sterilization tank 2, the first valve 11, the second valve 14 and the third valve 15 are closed, the steam supply valve 9 is opened, and the steam supply line 8 is passed through. The inside of the sterilization tank 2 is filled with high-temperature and high-pressure clean steam. Then, the steam supply valve 9 is controlled, and the sterilization tank 2 holds the set sterilization temperature (second set value pressure P2) for a predetermined time to perform the sterilization process. In this sterilization process, high-temperature steam passes through the bag 7 to sterilize the article 1 to be sterilized.

(Drying process)
When the sterilization process is finished, the steam supply valve 9 is closed to stop the steam supply into the sterilization tank 2, the third valve 17 is opened, and the steam in the sterilization tank 2 is discharged from the exhaust line 16. After the pressure in the sterilization tank 2 is lowered to near atmospheric pressure, the drying process is started.

  In this drying process, the reduced pressure exhaust process and the return pressure process are repeated. The decompression / exhaust process is performed in the same manner as the air exhaust process. However, since the inside of the bag 7 is wet during the first to third decompression / exhaust processes, the adjustment process is performed. That is, the first valve 11 is closed, the second valve 14 is opened, the vacuum pump 12 is operated, and the inside of the sterilization tank 1 is evacuated and exhausted at the low exhaust speed B through the bypass line 13. The moisture of the article to be sterilized 1 is excluded. This decompression exhaust process is performed until the detected value by the pressure sensor 22 reaches the first set value P1 lower than the atmospheric pressure.

  As described above, since the exhaust is performed under reduced pressure at the low exhaust speed B, the expansion of the article to be sterilized 1 is suppressed even when the bag 7 is in a wet state, and the bag 7 can be prevented from being ruptured.

  The return pressure step after the decompression and exhaust step is performed by opening the return pressure valve 19 for a short time and introducing clean air into the sterilization tank 2 through the filter 20. This return pressure process ends when the detected value of the pressure sensor 22 reaches atmospheric pressure.

  When the return-pressure process after the third decompression-exhaust process is completed, the decompression-exhaust process at the high exhaust speed A similar to the conventional one is performed. That is, the first valve 11 is opened, the second valve 14 is closed, and the vacuum pump 12 is operated, so that the inside of the sterilization tank 2 is evacuated at a high pumping speed A. In the third and subsequent decompression and evacuation processes, the wet state in the bag 7 is reduced by the drying process. Therefore, the sterilized object 1 expands even when the evacuation is performed at the high pumping speed, and the bag 7 Will not burst.

  Thus, the time required for the drying process can be shortened by making the adjustment process a part of the drying process, that is, by limiting the number of times of performing vacuum exhaust at the low exhaust speed B. As a result, the sterilization time can be shortened.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and only different configurations will be described.

  The difference is the configuration of the exhaust speed adjusting means, and the second embodiment is configured such that the bypass line 13 of the first embodiment is not provided. That is, when the adjustment process is performed using the first valve 11 as an adjustment valve whose flow resistance can be adjusted, the low exhaust speed B is obtained by reducing the opening of the first valve 11, and the adjustment is performed. When the process is not carried out, the high exhaust speed A is obtained by increasing the opening of the first valve 11. The exhaust speed is adjusted by the controller 6.

  The present invention is not limited to the first embodiment and the second embodiment. For example, the adjustment process can be configured to perform only one of the air exclusion process and the drying process. Moreover, the said adjustment process can be comprised so that it may implement in all the processes of the said air exclusion process or the said drying process. In this case, there is a disadvantage that the sterilization operation time becomes long. Further, the exhaust speed by the first exhaust means can be a plurality of stages or stepless.

It is a schematic block diagram of Example 1 of this invention. It is a time (horizontal axis) -pressure (vertical axis) characteristic diagram showing the operation of the first embodiment. It is a schematic block diagram of Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Object to be sterilized 2 Sterilization tank 3 Steaming means 4 First exhaust means 5 Pressure-reducing means 6 Controller (control means)
7 bags (sterilization bags)

Claims (2)

A sterilization tank that wraps in a sterilization bag and accommodates an object to be sterilized including a moisture-permeable waterproof material, a steam supply means that supplies steam for sterilization to the sterilization tank, and the sterilization tank by depressurizing the sterilization tank An exhaust means for exhausting the gas in the interior, a return pressure means for returning the pressure in the sterilization tank, an air exhaust means for controlling the steam supply means, the exhaust means and the return pressure means to discharge the air in the sterilization tank In a steam sterilization apparatus comprising a control means for sequentially performing a process, a sterilization process for steaming into the sterilization tank to sterilize an object to be sterilized, and a drying process for drying the object to be sterilized,
The exhaust means includes an exhaust speed adjusting means provided with a resistance adjusting member, and is configured to be adjustable to a high exhaust speed and a low exhaust speed at which the reduced pressure exhaust speed is adjusted by the resistance adjusting member. , By repeating the vacuum exhaust in the sterilization tank and steaming into the sterilization tank, the air exclusion step,
In this air evacuation step, when an object to be sterilized containing a moisture permeable and waterproof material is accommodated in the sterilization tank, the evacuation means is evacuated at the high evacuation speed during the first evacuation step, and then the evacuation step In the exhaust process, the steam sterilization apparatus is characterized in that an adjustment process for reducing the exhaust speed is performed. A sterilization tank that wraps in a sterilization bag and accommodates an object to be sterilized including a moisture-permeable waterproof material, a steam supply means that supplies steam for sterilization to the sterilization tank, and the sterilization tank by depressurizing the sterilization tank An exhaust means for exhausting the gas in the interior, a return pressure means for returning the pressure in the sterilization tank, an air exhaust means for controlling the steam supply means, the exhaust means and the return pressure means to discharge the air in the sterilization tank In a steam sterilization apparatus comprising a control means for sequentially performing a process, a sterilization process for steaming into the sterilization tank to sterilize an object to be sterilized, and a drying process for drying the object to be sterilized,
The exhaust means includes an exhaust speed adjusting means provided with a resistance adjusting member, and is configured to be adjustable to a high exhaust speed and a low exhaust speed at which the reduced pressure exhaust speed is adjusted by the resistance adjusting member. The drying step is repeated by repeating depressurization exhausting the atmospheric pressure below the atmospheric pressure in the sterilization tank and returning pressure by introducing the external air inside the sterilization tank, or introducing the external air while reducing the pressure inside the sterilization tank below the atmospheric pressure. Done
In this drying process, when an object to be sterilized containing a moisture-permeable and waterproof material is accommodated in the sterilization tank, the exhaust means is adjusted to the low exhaust speed for the vacuum exhaust process two to three times from the start of the drying process. A steam sterilization apparatus characterized in that a process is performed, and a subsequent vacuum exhaust process performs vacuum exhaust at the high exhaust speed.

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