JPH09266943A - Operation of sterilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhaust air in a sterilizer within a short time, by raising the temperature of a matter to be sterilized in a sterilizer up to a prescribed level and guiding pressurized air into a sterilizing vessel in a pretreatment process to discharge air in the sterilizing vessel. SOLUTION: A first steam supply valve 5 and a saturated steam supply valve 8 are opened to supply pressurized steam to a sterilizing vessel 1 for warming up at a cool state start. Next, the steam supply valve 8 is closed and an exhaust valve 29 is opened to discharge steam through an exhaust line 22 to make the inside of the vessel 1 to be the atmospheric pressure. Going to a pretreatment process after that, a third steam supply valve 16 is opened to supply steam to a heat exchanger 9 to heat steam in a first steam supply line 3. Air in the vessel 1 is purged out to be eliminated to an exhaust line 18 through the heat exchanger 9 by opening a superheated steam supply valve 7 and the exhaust valve 29 to guide steam in the steam supply line 3 into the vessel 1. This purging and guiding are repeated to perform the sterilizing process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method of operating a sterilizer for sterilizing medical supplies and the like.

[0002]

2. Description of the Related Art For example, a steam sterilizer is a device for hermetically storing an object to be sterilized in a sterilization tank and heating and sterilizing it by sending pressurized steam into the sterilization tank. As a pretreatment step prior to this sterilization step, an operation of preheating the sterilization tank and the object to be sterilized contained therein, a vacuum suction in the sterilization tank, and a few steam supply to the sterilization tank during this vacuum suction The air inside the sterilization tank, including the inside of the object to be sterilized, is removed. The former preheating is to suppress the amount of condensation of the steam sent during the execution of the sterilization process, and the latter exclusion of air causes the steam sent during the execution of the sterilization process to act inside the object to be sterilized to ensure reliable sterilization. It is a journey for.
As a configuration for preheating the object to be sterilized, there is a structure in which a steam jacket for heating is provided on the outer circumference of the sterilization tank, or an electric heater is provided on the outer circumference of the sterilization tank or in the sterilization tank.

In such a sterilizer, preheating during the pretreatment step is due to radiative heat transfer by a steam jacket or an electric heater and heat transfer by natural convection of air in the sterilization tank. Therefore, when sterilizing an object to be sterilized such as patient clothes and surgical gown in a sterilization metal can called a cast for sterilization, it is difficult to sufficiently preheat the inside of the object to be sterilized. Further, as described above, in the pretreatment process, steam is supplied when air is removed, but since the sterilization tank is in a depressurized state, its steam temperature is the saturated steam temperature (for example, , -0.8 kg / cm ² G is about 60 ° C), which is lower than the temperature of the supplied steam. Therefore, the object to be heated is cooled by the steam in the sterilization tank, and it takes a long time to preheat the object to be sterilized. However, if this preheating is not carried out sufficiently, steam will come into contact with the object to be sterilized in a low temperature state in the subsequent sterilization process to condense, and the object to be sterilized in the cast will be in a wet state,
There is a problem that condensed water accumulates in the cast.

Therefore, generally, after the sterilization step, a post-treatment step for drying the material to be sterilized is performed. However, when a large amount of condensed water is generated in this way, a long time is required for the post-treatment step. . Moreover, in the post-treatment process, since it is generally a vacuum drying method in which the air in the sterilization tank is removed by a water-sealed vacuum pump and dried, a long time is required due to leakage of the vacuum line. . That is, in the steam sterilizer, the pretreatment process requires a long time, and shortening the time of the pretreatment process is an important issue for efficient operation of the sterilizer.

[0005]

The problem to be solved by the present invention is to raise the temperature in a short time not only in the sterilization tank but also in the object to be sterilized during the pretreatment process of the sterilizer.
Moreover, it is an object of the present invention to provide a method of operating a sterilizer capable of eliminating air in the sterilization tank in a short time.

[0006]

The present invention has been made to solve the above problems, and the invention according to claim 1 raises the temperature of the object to be sterilized in the sterilization tank to a predetermined temperature. At the same time, after performing a pretreatment process to remove the air in the sterilization tank, the sterilizer performing the sterilization process removes the air by introducing and discharging pressurized steam into the sterilization tank 1 during the pretreatment process. The invention according to claim 2 further comprises: after introducing pressurized steam into the sterilization tank to a predetermined pressure during the pretreatment step,
This pressure is maintained for a certain period of time and then discharged.
Further, the invention according to claim 3 is such that the introduction and discharge of the pressurized steam are repeated a plurality of times during the pretreatment process.

Further, in the invention according to claim 4, when the introduction and the discharge of the pressurized steam are repeated a plurality of times during the pretreatment step, the sterilization tank inside the sterilization tank at the end of the introduction of the pressurized steam each time is introduced. The pressured steam is introduced so that the pressure of the pressurized steam gradually increases, and the invention according to claim 5 is such that the pressure in the sterilization tank is sequentially increased at the end of each discharge of the pressurized steam. The pressurized steam is discharged. In the invention according to claim 6, when the introduction and the discharge of the pressurized steam are repeated a plurality of times, the pressure in the sterilization tank at the end of the introduction of the pressurized steam is sequentially increased, and the pressure of each time is increased. The pressurized steam is introduced and discharged so that the pressure in the sterilization tank at the end of discharging the pressurized steam is gradually increased.

Further, the invention according to claim 7 includes an operation of purging the inside of the sterilization tank with pressurized steam to eliminate air during the pretreatment step.

Further, in the invention described in claim 8, the pressurized steam used in the pretreatment step is superheated steam.

Further, in the invention described in claim 9, when the pressurized steam is discharged during the pretreatment step, the pressurized steam is discharged while being condensed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is applied to a pretreatment process of a sterilizer. This pretreatment step is a step of uniformly raising the temperature of the object to be sterilized to the inside prior to the sterilization step as described above, and excluding air in the sterilization tank including the inside of the object to be sterilized, This is a process for efficiently performing each subsequent process. That is, in the case of a steam sterilizer,
The vapor supplied in the sterilization step is prevented from condensing on the surface of the object to be sterilized as much as possible, a predetermined sterilization effect by the vapor is secured, and the time required for drying after the sterilization step is shortened. Further, in the case of a gas sterilizer, a predetermined sterilization effect by the sterilization gas is secured by maintaining the object to be sterilized and the inside of the sterilization tank at a predetermined temperature.

First, according to the first aspect of the invention, by introducing and discharging pressurized steam into the sterilization tank in the pretreatment process, the sterilization tank and the preheating of the object to be sterilized and the air in the sterilization tank are removed. Exclude and perform. That is, since preheating of the sterilization tank and the object to be sterilized is direct heating by the pressurized steam introduced into the sterilization tank, the pretreatment process in the sterilizer can be shortened. Furthermore, since vapor has a smaller specific gravity than air and a large difference in density between the two, mixing with air is less likely to occur. Therefore, the air in the sterilization tank is pushed out by the pressurized steam and the sterilization tank is filled with steam, whereby the air can be efficiently removed.

Therefore, in the case of the steam sterilizer, the heat of the pressurized steam can be applied to the inside of the object to be sterilized during the sterilization process, and the drying after the sterilization process can be shortened. In this case, the sterilizing gas can be applied to the inside of the object to be sterilized. When introducing the pressurized steam into the sterilization tank, it is preferable to limit the flow rate to a small amount to prevent mixing with the air in the sterilization tank.

Further, the pressurized steam introduced into the sterilization tank can directly preheat the sterilization tank including its pressure resistant door, and at the same time, the object to be sterilized can also be directly preheated. (EN) A sterilizer such as an electric heater that does not require a heating means that makes the sterilizer large and complicated is achieved, and the sterilizer can be made compact and lightweight.

Here, the pressurized steam introduced into the sterilization tank is
The higher the pressure and the higher the temperature, the greater the effect. However, it is determined by the shape and material of the sterilized object and the structure of the sterilizer to which the present invention is applied. For example, when the object to be sterilized is deformed or deteriorated by heating, the pressure and temperature are set relatively low.

Next, in the invention described in claim 2, when the pressurized steam is introduced, it is introduced to a predetermined pressure in the sterilization tank, and this pressure is maintained for a certain period of time and then discharged. By this operation, the saturated steam temperature in the sterilization tank is maintained substantially constant, so that the sterilization tank is preheated to a predetermined temperature during this period. In this case, even if the material to be sterilized is a porous material such as cloth, the pressurized steam easily penetrates into the interior thereof. Therefore, the object to be sterilized is uniformly preheated to the inside thereof. Furthermore, when the inside of the sterilized object is surely preheated, the air inside the sterilized object expands, and this expansion promotes separation from the sterilized object.

Next, in the invention as set forth in claim 3, the pressurized steam is introduced and discharged repeatedly a plurality of times during the pretreatment process so that it remains in the sterilization tank each time the pressurized steam is discharged. Since the air can be eliminated, the final remaining amount of air is extremely small.

Next, in the invention described in claim 4, when the introduction and the discharge of the pressurized steam are repeated a plurality of times in this way, the pressure of the pressurized steam introduced each time is increased successively, The amount of heat retained by the pressurized steam is gradually increased. In this case, since the degree of heating of the object to be sterilized is successively increased each time the pressurized steam is introduced, the object to be sterilized is effectively heated.

Next, in the invention described in claim 5, when the introduction and discharge of the pressurized steam are repeated a plurality of times, the pressure in the sterilization tank at each discharge is successively higher than that at the end of the previous discharge. By setting the pressure, the amount of decrease in the temperature in the sterilization tank is reduced. In this case, when the pressurized steam is discharged, it is possible to suppress the heat radiation from the object to be sterilized to the pressurized steam, which allows the temperature of the object to be sterilized to be increased continuously, so that it is possible to reach the center of the object to be sterilized. The temperature can be raised uniformly.

Next, according to the invention of claim 6,
When the introduction and discharge of pressurized steam are repeated multiple times,
The pressure of the pressurized steam introduced each time is sequentially increased, and the pressure at the end of each evacuation is made higher than the pressure at the end of the previous evacuation, so that the sterilization target object is evacuated each time the pressurized steam is introduced. By gradually increasing the heating degree and reducing the amount of decrease in the saturated steam temperature in the sterilization tank, it is possible to suppress the heat radiation from the object to be sterilized to the pressurized steam and simultaneously increase the temperature of the object to be sterilized. As a result, it is possible to uniformly preheat the center of the object to be sterilized.

Further, in the invention according to the seventh aspect, air in the sterilization tank is removed by performing an operation of purging the inside of the sterilization tank with pressurized steam during the pretreatment process. In this purging operation, pressurized steam is supplied to the sterilization tank and, at the same time, the exhaust pipe and the like are opened and discharged, so that the air in the sterilization tank is effectively removed. That is, the air inside the sterilization tank is replaced by the pressurized steam, and the difference in specific gravity from the air inside the sterilization tank is used to expel the air so as to push it out. In this case, if the pressurized steam is introduced from above the sterilization tank and the air is discharged from below the sterilization tank, this difference in specific gravity can be effectively utilized. Further, at this time, by using a diffusion means such as a diffuser to uniformly supply the pressurized steam to the entire sterilization tank, the air is uniformly pushed out and the time required is shortened.

Further, in the invention according to claim 8, the pressurized steam introduced into the sterilization tank at the time of executing the pretreatment step is superheated steam. Superheated steam is less likely to condense than saturated steam, and the amount of drain generated is smaller than that of saturated steam.Because droplets are taken in, it adheres to the sterilization object before entering the sterilization process. The temperature can be raised while efficiently removing the remaining water. Therefore, in the pretreatment process, when the introduction and discharge of the pressurized steam are repeated a plurality of times, the water taken into the superheated steam can be discharged to the outside of the sterilization tank every time the superheated steam is discharged. The degree of drying of the sterilized object increases.

As means for obtaining the above-mentioned superheated steam, means for further heating saturated steam or for rapidly reducing pressure is used. For example, when heating saturated steam, when the sterilizer uses steam, it is heated by exchanging heat with steam from a steam generator originally connected to the sterilizer. This method is effective especially in a steam sterilizer because it can use an existing device, but can also be applied to a gas sterilizer that uses steam in a pretreatment step and a humidification step.

It is also possible to improve the dryness by passing steam from a steam generator or the like through a steam separator, and reduce the pressure in this state to turn it into superheated steam.
As a means for reducing the pressure in this case, in addition to using a general pressure reducing valve, when introducing the saturated steam into the sterilization tank, if the pressure in the sterilization tank is set lower than the pressure of the saturated steam, When the saturated steam flows into the sterilization tank, it is rapidly depressurized to become superheated steam.

Further, in the case where an electric heating means is used to heat (or preheat) the inside of the sterilization tank or generate steam as in some sterilizers, a part of the electric heating means or a newly installed electric heating means is used. The saturated steam is heated by means. As the electric heating means, in addition to a general electric heater, a heating means utilizing the principle of induction heating or dielectric heating is included. In addition, even if a steam generator such as a steam sterilizer is used for heating superheated steam, or conversely, even if a sterilizer equipped with electric heating means is used for heating superheated steam. It also includes the case where this steam is used by installing a steam generator.

Further, in the invention as set forth in claim 9, when the pressurized steam is discharged from the sterilization tank, the pressurized steam is condensed and discharged as condensed water while reducing the volume. Efficiently discharge in a short time. Various well-known means can be applied as means for condensing the pressurized steam, but for example, a heat exchanger using water as a cooling medium is used. A well-known vacuum pump can be used as a suction / discharge means for the pressurized steam (including superheated steam).
Since not only pressurized steam but also droplets are discharged from such a sterilizer, a water-sealed vacuum pump or an ejector-type vacuum pump that uses fluid pressure (for example, a jet pump) is used. Is preferred. At this time, a water-sealed vacuum pump is advantageous in terms of the amount of water used, but when a jet pump is used and water is selected as a fluid for operation, it can also be used as a cooling device.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a drawing for explaining a first embodiment of a pressurized steam supply pattern in the method for operating a sterilizer according to the present invention, and FIG. 2 applies the method for operating a sterilizer according to the present invention. It is explanatory drawing which shows an example of a steam sterilizer.

First, an example of a sterilizer to which the present invention is applied will be described with reference to FIG. In FIG. 2, the sterilization tank 1 for accommodating the sterilization object has an entrance / exit for the sterilization object provided with a pressure resistant door (not shown), and the inside of the sterilization tank 1 can be completely sealed by closing the pressure resistant door. .

The sterilization tank 1 is connected to a first steam supply line 3 through which pressurized steam used in a pretreatment process or a sterilization process passes. Here, steam supply refers to supply of steam. To the first steam supply line 3, a steam separator 4, a first steam supply valve 5, and a steam supply pressure adjusting valve 6 for pressure adjustment are sequentially connected from the upstream side in the flow direction of the pressurized steam. Further, on the downstream side of the steam supply pressure adjusting valve 6 in the first steam supply line 3,
The superheated steam supply valve 7 and the saturated steam supply valve 8 are connected in parallel, and a heat exchanger 9 for heating steam is connected downstream thereof. Here, the steam separator 4 is the first steam supply line 3
Is for increasing the dryness of steam from the sterilization tank to efficiently supply heat to the sterilization tank 1, and also suppresses generation of condensed water (drain) in the sterilization tank 1 and the heat exchanger 9. To do. Also,
The flow rate of steam passing through the superheated steam supply valve 7 is set to be smaller than the flow rate of steam passing through the saturated steam supply valve 8.

An air supply line 13 having an air filter 12 at one end is connected to the sterilization tank 1, and an air supply valve 14 is connected in the middle of the air supply line 13.

The heat exchanger 9 is connected to a third steam supply line 15 branched from the first steam supply line 3. The supply of steam is controlled by the opening / closing control of the third steam supply valve 16 connected in the middle of the third steam supply line 15. The steam from the third steam supply line 15 heats the pressurized steam in the first steam supply line 3 in the heat exchanger 9, and then joins to a discharge line 18 described later via the first drain line 17. . A first steam trap 19 is connected in the middle of the first drain line 17, and only the drain is discharged from the discharge line 18.

The discharge line 18 has an upstream end connected to the sterilization tank 1, and a cooling device 20 connected in the middle thereof. In this embodiment, this cooling device 20 is exemplified as a heat exchanger that uses a cooling liquid as one heat medium, and a cooling liquid supply line 25 equipped with a cooling valve 24 and a drain line 26 are connected in the middle thereof. is there. This drain line 26
May be merged with the discharge line 18.

On the downstream side of the cooling device 20, the discharge line 18 is branched into three systems of a vacuum line 21, an exhaust line 22 and a second drain line 23. Vacuum line 21
A vacuum control valve 27 and a vacuum pump 28 are connected to
An exhaust valve 29 is connected to the exhaust line 22, and a second steam trap 30 is connected to the second drain line 23.

Further, a third drain line 31 extending from the steam separator 4 is connected to the discharge line 18. A third steam trap 33 is inserted in the middle of the third drain line 31. This third drain line 31
Is connected to the discharge line 18 on the downstream side of the discharge line 18 where the vacuum line 21, the exhaust line 22, and the second drain line 23 join again.

Further, in the illustrated embodiment, a controller 40 for controlling the operation of the sterilizer is provided, and the controller 40 detects the operating state of the sterilizer based on a preset procedure. The vacuum pump 28 and each valve are appropriately controlled according to the signal from the means. In the illustrated embodiment, as such a detection means, a pressure detection means 41 for monitoring the pressure in the sterilization tank 1 and a temperature detection means for monitoring the temperature in the sterilization tank 1 based on the temperature of the discharge line 18 are used. 42 is illustrated.

With the above-mentioned structure, after the sterilization object is carried into the sterilization tank 1, the sterilization work is performed according to the following procedure. In the following description, each valve is basically closed unless its operation is specified. Also, sterilization tank 1
The change in internal pressure will be described with reference to FIG.

Here, the pressurized steam introduced into the sterilization tank 1 exerts a greater effect as the pressure becomes higher and the temperature becomes higher, but the present invention is applied in addition to the shape and material of the object to be sterilized. Determined by the structure of the sterilizer. That is, when the object to be sterilized is deformed or deteriorated by heating, the temperature is set relatively low. When applying to an existing sterilizer, the pressure is determined by considering the pressure limit of the sterilizer, but with a general sterilizer, the pressure is about 2.5 kg / cm.
^Since it is ² G, the steam pressure should be about 2.2 kg / cm ² G. On the other hand, when it is applied to a newly manufactured sterilizer instead of being applied to an existing sterilizer, it is not restricted by such a limitation. The same applies to the pressure of saturated steam supplied in the sterilization process. In the following embodiments, superheated steam and saturated steam will be described as being supplied to the same set pressure in the sterilization tank 1. Further, in this embodiment, the pressurized steam introduced into the sterilization tank 1 is heated by the heat exchanger 9 and then,
Since it becomes superheated steam, hereinafter, the pressurized steam heated by the heat exchanger 9 is simply referred to as superheated steam.

The sterilizer of this embodiment has a cold start-up (when the first start-up of the sterilizer of the day or even on the same day,
The sterilization tank 1 is warmed up when the sterilization tank 1 is cold with the passage of time). That is, the first steam supply valve 5 and the saturated steam supply valve 8 are opened, and the pressurized steam from the steam generator is supplied to the sterilization tank 1 through the first steam supply line 3. Here, the sterilizer is assumed to close the pressure resistant door.

From the pressurized steam (saturated steam) flowing through the first steam supply line 3, droplets (saturated water, condensed water, etc.) are removed by the steam separator 4, and the dryness is improved. And
The pressurized steam in the first steam supply line 3 is supplied to the steam supply pressure adjusting valve 6
After adjusting the pressure to a predetermined pressure (for example, 2.2 kg / cm ² G), the sterilization tank 1 and its pressure-proof door are heated from the inside. The pressurized steam that has heated the sterilization tank 1 is discharged from the second drain line 23 as drain. By the above operation, the entire sterilization tank 1 including the pressure resistant door is preheated. At this time, the liquid droplets separated by the steam separator 4 are discharged from the third drain line 31 through the discharge line 18.

After that, the saturated steam supply valve 8 is closed and the exhaust valve 29 is opened to discharge the pressurized steam from the exhaust line 22 so that the sterilization tank 1 is brought to the atmospheric pressure. At this time, the third steam supply valve 16 is opened and steam is supplied from the third steam supply line 15 to the heat exchanger 9 to heat the pressurized steam flowing in the first steam supply line 3 and to sterilize the sterilization tank 1. You may make it supply superheated steam inside. As a result, the amount of drain generated in the sterilization tank 1 can be reduced.

The above warming-up step is preferably executed at the time of cold start, but can be omitted at the time of continuous sterilization work. That is, when the sterilization tank 1 is in a cold state, the condensed amount of the pressurized steam is large after the pretreatment process.

Next, a pretreatment step is performed. In this state, the sterilization tank 1 is warmed up by the introduction of pressurized steam and is heated to a predetermined temperature. Further, saturated steam having a high degree of dryness is supplied to the heat exchanger 9 by the steam separator 4.
In this state, the third steam supply valve 16 is opened to start steam supply from the third steam supply line 15 to the heat exchanger 9. The steam supplied into the heat exchanger 9 is used to heat the pressurized steam (saturated steam) in the first steam supply line 3.

When the superheated steam supply valve 7 and the exhaust valve 29 are opened, the pressurized steam in the first steam supply line 3 becomes
It flows toward the sterilization tank 1 and is heated in the heat exchanger 9 on the way to become superheated steam. This superheated steam is used in the sterilization tank 1.
When it flows in, it is decompressed and expands, further increasing the degree of superheat. By introducing the pressurized steam as superheated steam into the sterilization tank 1 in this way, the air in the sterilization tank 1 is pushed out toward the discharge line 18 and is removed from the discharge line 18 via the exhaust line 22. In this way, by introducing so-called superheated steam into the sterilization tank 1 and discharging it as it is, so-called purging operation is performed, so that air having a large specific gravity is pushed downward from above by the superheated steam having a small specific gravity,
Excluded from the discharge line 18. At the same time, the heat of the superheated steam itself heats the sterilization tank 1 and the pressure resistant door from the inside, thereby heating the object to be sterilized.

Further, since the air remaining in the sterilized object expands due to the heating of the sterilized object, the separation from the sterilized object is promoted, and the separated air is pushed out by the superheated steam and removed from the discharge line 18. To be done. Since the steam flow rate passing through the superheated steam supply valve 7 is set lower than the steam flow rate passing through the saturated steam supply valve 8 as described above, the superheated steam flowing into the sterilization tank 1 is It is possible to prevent the air remaining inside from being stirred and effectively eliminate the air.

After performing the above purging operation for a certain period of time,
When the exhaust valve 29 is closed, the pressure inside the sterilization tank 1 rises as shown in FIG. 1 with the introduction of superheated steam. The supply of superheated steam is continued until the inside of the sterilization tank 1 reaches a predetermined pressure, and when this pressure is reached, the exhaust valve 29 is opened and the superheated steam is discharged. At the time of this discharge, the air remaining in the sterilization tank 1 is expelled again by being pushed out by the superheated steam. Then, when almost all the superheated steam inside the sterilization tank 1 is discharged and the pressure drops to almost atmospheric pressure, the exhaust valve 2
9 is closed, and superheated steam is introduced and discharged in the same procedure as described above.

By repeating the introduction and discharge of the superheated steam, the air taken into the sterilization tank 1 and the object to be sterilized is eliminated. By repeatedly exhausting and introducing this superheated steam several times, even the air contained in the object to be sterilized is sufficiently removed, and uneven heating of the steam in the subsequent sterilization process is reduced.

In addition, by repeating the introduction and discharge of superheated steam a plurality of times in the pretreatment process, it is possible to discharge the moisture taken into the superheated steam to the outside of the sterilization tank 1 each time the superheated steam is discharged. it can. Therefore, the degree of drying of the object to be sterilized can be increased, and also by this, the action of preheating the inside of the object to be sterilized can be promoted.
In particular, since the superheated steam can be introduced and discharged in this manner only by opening and closing the superheated steam supply valve 7 and the exhaust valve 29, the conventional vacuum suction means for discharging air is unnecessary. become. Further, at the time of discharging the superheated steam in this pretreatment process, the cooling valve 24
Is opened to supply the cooling liquid to the cooling device 20, and the cooling device 20 rapidly condenses the superheated steam flowing into the discharge line 18, thereby shortening the discharging time and improving the efficiency.

Regarding the air elimination operation in the pretreatment step, the sterilizer adopting the method of the present invention and the conventional steam sterilizer using a conventional water-sealed vacuum pump are used in the sterilization tank 1. The time required to remove air to the same level was 7 minutes for the former and 15 minutes for the latter.
In addition, when the time required for the temperature of the center of the sterilized object to reach 150 ° C is measured using the one in which the material to be sterilized such as cloth is stored in the cast, it takes 15 minutes for the former and 3 minutes for the latter. there were. At this time, a superheated steam having a pressure of 2.2 kg / cm ² G and a temperature of 145 ° C. was supplied to the sterilizer employing the method of the present invention.

This means that the pretreatment process can be shortened to 1/2 or less.
Since it is not necessary to separately provide the operation for preheating and the operation for removing air, the pretreatment process can be further shortened, and therefore the sterilization operation itself can be greatly shortened. Further, the heat of the superheated steam supplied during the sterilization process can be reliably transmitted to the object to be sterilized without being obstructed by the residual air. In addition, by making the pretreatment process slightly longer than the above time, the residual rate of air is further reduced, so that the heat of the superheated steam supplied during the sterilization process prevents the remaining air from acting on the object to be sterilized. The entire object to be sterilized can be uniformly heated and sterilized without being heated.

As described above, by introducing the superheated steam into the sterilization tank 1, the air in the sterilization tank 1 is removed by utilizing the difference in specific gravity, and the object to be sterilized is directly heated by preheating. Can be done. Further, due to the heat from the superheated steam, water droplets (condensed water) adhering to the object to be sterilized are taken into the superheated steam as steam and are discharged together with the superheated steam in this state. Moreover, this preheating, like the conventional sterilizer,
Since it does not rely on the heat radiation from the inner wall of the sterilization tank by the steam jacket, it is the direct heating by superheated steam,
The temperature of the object to be sterilized can be efficiently raised before entering the sterilization process. Therefore, the pretreatment process in the sterilizer can be shortened, and in the case of the steam sterilizer, the heat of the superheated steam can be applied to the inside of the object to be sterilized during the sterilization process, and the drying in the post-treatment process can be performed. The time can be shortened.

By the operations described above, the exhaust treatment for preheating the object to be sterilized and the inside of the sterilization tank 1 and eliminating the air inside the sterilization tank 1 is completed, and in the sterilization step of the next step, it is replaced with superheated steam and saturated. Introduce pressurized steam in the state. This switching is performed by supplying superheated steam at the start of the sterilization process following the pretreatment process and closing the superheated steam supply valve 7 at a stage where the pressure in the sterilization tank 1 is slightly lower than the set pressure in the sterilization process. This is done by opening the steam supply valve 8. By this switching, the time for raising the steam temperature in the sterilization tank 1 to a predetermined sterilization temperature can be shortened. At this time, the supply of steam to the heat exchanger 9 is stopped by closing the third steam supply valve 16. In the present invention, if the superheated steam in the sterilization tank 1 is discharged at the end of the pretreatment process,
The supply of saturated steam can be started, and in the special case where superheated steam is used for sterilization, the superheated steam is supplied as it is without switching to the supply of saturated steam.

By the above operation, when the temperature in the sterilization tank 1 by the temperature detecting means 42 reaches the saturated vapor temperature corresponding to the set pressure, the sterilization time starts to be measured, and this state is set to the time required for the sterilization process. Hold. In this sterilization process,
Since the material to be sterilized is sufficiently heated in the above-mentioned pretreatment process, saturated steam (pressurized steam) supplied from the first steam supply line 3 is not condensed in contact with the surface of the material to be sterilized. In addition, the generation of water drops is prevented. Therefore, the heat of the steam can be applied to the inside of the object to be sterilized, and the sterilization effect is ensured.

In the post-treatment step following the sterilization step, the saturated steam supply valve 8 is closed to stop the supply of saturated steam (pressurized steam) to the sterilization tank 1, the cooling device 20 is operated, and the vacuum pump is operated. 28 is activated. Then, the exhaust valve 29 is opened to discharge the saturated steam in the sterilization tank 1. At this time, the saturated vapor is rapidly condensed by the cooling device 20 and its volume is greatly reduced, so that the saturated vapor is efficiently and immediately discharged from the exhaust line 22.

When the pressure in the sterilization tank 1 approaches the atmospheric pressure, the exhaust valve 29 is closed and the vacuum control valve 27 is opened. Then, the saturated vapor remaining in the sterilization tank 1 is vacuum pump 28.
It is further discharged by vacuum suction of the sterilization tank 1 at this time.
The drain generated inside is also removed by suction. Further, by the action of the cooling device 20, the steam (including superheated steam) from the sterilization tank 1 is discharged while being condensed. In this post-treatment process, as described above, water droplets are prevented from adhering to the sterilization target in the sterilization process, and the sterilization target is less wetted, so that the post-treatment process can be shortened.

The above-mentioned supply state of the pressurized steam is detected by the control device 40 based on the signals from the pressure detecting means 41 and the temperature detecting means 42 provided in the sterilizer as described above. It is also possible to separately detect by attaching a detecting means to the supply pipe of superheated steam. Then, each valve and the vacuum pump 28 are controlled so that a predetermined supply state is achieved based on the detection result. In addition, after introducing pressurized steam into the sterilization tank 1, the time to maintain this state is
It is set by attaching an appropriate timer means (not shown) to the control device 40 or by incorporating it in the control device 40 itself.

When the above post-treatment process is completed, the air supply valve 1
4 is opened to allow the sterilization tank 1 to communicate with the outside through the air filter 12 so as to have the same pressure as the atmospheric pressure. Then, the pressure resistant door of the sterilization tank 1 is opened to take out the object to be sterilized, and the whole process is completed.
As described above, by reliably preheating the sterilized object, the pretreatment process can be shortened, and since the adhesion of water droplets in the post process can be prevented, the drying process can be shortened as a whole. The series of sterilization work can be shortened. Here, when the operation of the sterilizer is continued, the operations after the pretreatment step are repeated, but when the operation of the sterilizer is terminated at this point, the first steam feeding valve 5 and the third steam feeding valve Close each valve, such as 16.

In the above description, all the pressures of the superheated steam introduced into the sterilization tank 1 during the pretreatment process are discharged when they reach the same predetermined pressure, but as shown by the two-dot chain line in FIG. After introducing the superheated steam to a predetermined pressure, the predetermined pressure may be maintained for a certain period of time.
The superheated steam surely and evenly penetrates into the object to be sterilized (particularly in the case of a porous object to be sterilized such as cloth), so that the temperature inside the object to be sterilized can be raised. Also, the air remaining inside the object to be sterilized can be reliably removed.

Further, as shown in FIG. 3, when the introduction and discharge of superheated steam are repeated a plurality of times in the pretreatment process, the pressure in the sterilization tank 1 is adjusted to the value at the end of the previous exhaustion when the superheated steam is exhausted. The pressure should be gradually higher than the pressure. As a result, the amount of decrease in the temperature in the sterilization tank 1 can be reduced, the heat radiation from the object to be sterilized to the superheated steam can be suppressed, and the temperature of the object to be sterilized can be continuously increased. The temperature can be raised. That is, when discharging is performed until the pressure in the sterilization tank 1 becomes atmospheric pressure, the inside of the sterilization tank 1 communicates with the atmosphere through the discharge line 18, so that the steam temperature in the sterilization tank 1 becomes
The temperature will drop to the saturated steam temperature at atmospheric pressure (approximately 100 ° C). Therefore, even if the surface temperature of the object to be sterilized is increased by superheated steam, it will be lowered to the saturated steam temperature again (the saturated steam temperature of ² kg / cm ² G is
About 133 ℃). Since the temperature change inside the object to be sterilized occurs after the surface temperature, when the surface side is cooled in this way, the degree of increase in the internal temperature does not increase. Therefore, as shown in FIG. 3, when discharging the superheated steam for the first time, the superheated steam is not discharged to the atmospheric pressure, is interrupted at a pressure slightly higher than that, and the next superheated steam is immediately introduced. At the time of exhausting the superheated steam, the pressure in the sterilization tank 1 is set to be successively higher than the pressure at the end of the previous exhaust. As a result, the surface temperature of the object to be sterilized, as shown by the dotted line in FIG.
Although the temperature rises and falls almost in synchronism with a slight delay after the discharge operation, the temperature of the center of the object to be sterilized is a slope formed by the pressure at the end of exhaust of superheated steam, as shown by the chain double-dashed line in Fig. 3. And it keeps rising without lowering. Therefore, it is possible to reliably raise the temperature up to the central portion of the object to be sterilized, where the temperature hardly rises.

Further, as shown in FIG. 3, when the introduction and discharge of superheated steam are repeated a plurality of times in the pretreatment process, the pressure of the superheated steam introduced each time is increased successively to retain the superheated steam. The amount of heat may be increased sequentially. In this case, the degree of heating to the sterilized object increases with each introduction of superheated steam, so that the temperature of the sterilized object can be raised effectively, and the time from the start to the end of each introduction can be increased. Since it can be shortened, the time of the pretreatment process can be shortened as a whole.

As described above, according to the present invention, the pretreatment process can be shortened, and in the case of the steam sterilizer, the steam during the sterilization process can be applied to the inside of the object to be sterilized. The drying time in the post-treatment process can be shortened,
In the case of a gas sterilizer, the sterilizing gas can be applied to the inside of the object to be sterilized during the sterilization process.

Further, as described above, according to the present invention, a heating means such as a steam jacket is not necessary for preheating the sterilized object in the pretreatment step. However,
From the standpoint of thermal efficiency, it is preferable to prevent heat dissipation from the sterilization tank 1 after preheating and maintain the temperature during standby after the warm-up step or during post-treatment step after the sterilization step. Therefore, in the sterilizer shown in FIG. 2, the heating heat transfer tube 2 for maintaining the temperature is provided. The heating heat transfer tube 2 (hereinafter, simply referred to as a heating tube) 2 does not need to preheat the sterilization tank 1 or the object to be sterilized unlike the conventional sterilizer, and maintains the temperature of the sterilization tank as described above. Since the purpose is (heat retention), sterilization tank 1
It does not have to be as bulky and bulky as an all around steam jacket. It will be specifically described below with reference to FIG.

The heating tube 2 is arranged so as to surround the sterilization tank 1. The upstream end of this heating pipe 2 is
A second steam supply line 10 branching from the downstream of the steam supply pressure adjusting valve 6 in the first steam supply line 3 is connected. A second steam supply valve 11 is connected in the middle of the second steam supply line 10. Furthermore, the downstream end of the heating pipe 2 is further connected to a fourth drain line 32 that joins the discharge line 18. A fourth steam trap 34 is inserted in the middle of the fourth drain line 32. The connection point of the fourth drain line 32 to the discharge line 18 is the vacuum line 21, the exhaust line 22, and the second drain line 23.
Is on the downstream side of the discharge line 18 where they joined again. The supply of steam to the heating pipe 2 is performed through the second steam supply line 10 by opening the second steam supply valve 11 during the warm-up stroke during the cold start. After flowing through the heating pipe 2 to heat the sterilization tank 1, it is discharged from the fourth drain line 32 as drain. Then, even after this warming stroke, the second steam feeding valve 11 is opened as it is to maintain the state in which the steam is circulated in the heating pipe 2, and as a heat retaining means for maintaining the sterilization tank 1 at a predetermined temperature. Make it work.

Needless to say, the operation method described above can be applied to not only the sterilizer shown in FIG. 2 but also a general sterilizer equipped with a steam jacket. When applied to a sterilizer equipped with such a steam jacket, steam supply to the steam jacket may be performed in the same manner as the heating pipe 2 in the sterilizer shown in FIG. That is, during the warm-up process such as cold start, steam is supplied to the steam jacket simultaneously with the sterilization tank 1. Then, even after this warming-up step, the state where steam is circulated in the steam jacket is maintained as it is, and the sterilization tank is maintained at a predetermined temperature. Since the steam jacket in this case functions not as a heating means for preheating the object to be sterilized but as a heat retaining means for maintaining the temperature of the sterilization tank, the amount of steam to be supplied is significantly reduced.

[0064]

As described above, according to the first aspect of the present invention, since the sterilization tank and the object to be sterilized can be directly heated by the pressurized steam, preheating of these can be performed in a short time. In addition, the difference in specific gravity between steam and air can be used to remove the air by pushing it out with pressurized steam, so that the air can be efficiently removed in a short time.
Furthermore, the heat of the pressurized steam expands the air in the sterilization tank, which promotes the removal of air and the separation of air from the object to be sterilized. it can. Therefore, according to the invention described in claim 1, the time of the pretreatment process can be shortened, and furthermore, the sterilization process can be surely preheated and the air in the sterilization process can be reliably removed. The sterilization effect in can be enhanced.

Further, according to the invention of claim 1,
With the pressurized steam introduced into the sterilization tank, the sterilization tank can be directly preheated including its pressure resistant door, and at the same time, the object to be sterilized can also be directly preheated. A heating means that makes the structure of the sterilizer large and complicated is not required, and the size and weight of the sterilizer can be reduced.

Further, according to the invention described in claim 2,
When the pressurized steam is introduced during the pretreatment process, the pressurized steam is introduced into the sterilization tank up to a predetermined pressure, and the pressure is maintained for a certain period of time and then discharged, so that the pressurized steam is discharged to the object to be sterilized (especially for cloth or the like). For example, in the case of a porous material), it penetrates evenly and surely into the inside of the sterilization tank.
Also, the air in the object to be sterilized can be separated while expanding.

Further, according to the invention described in claim 3, the amount of residual air in the sterilization tank is reduced to a very low level by repeating the introduction and discharge of the pressurized steam a plurality of times during the pretreatment process. it can.

Further, according to the invention as set forth in claim 4, the pressure of the pressurized steam introduced each time is successively increased to sequentially increase the retained heat amount of the pressurized steam. In addition, the degree of heating to the sterilized object can be increased sequentially, the temperature of the sterilized object can be effectively raised, and the time from the start to the end of each introduction can be shortened, so the time of the pretreatment process as a whole can be shortened. .

Further, according to the invention described in claim 5, when the introduction and discharge of the pressurized steam are repeated a plurality of times in this way, the pressure at the end of each exhaust is higher than that at the end of the previous exhaust. By reducing the saturated steam temperature in the sterilization tank, the heat radiation from the object to be sterilized to the pressurized steam can be suppressed, and the temperature of the object to be sterilized can be continuously increased. Can even preheat up to the part.

In addition, according to the invention of claim 6,
When the introduction and discharge of pressurized steam are repeated multiple times,
The pressure of the pressurized steam introduced each time is sequentially increased, and the pressure at the end of each evacuation is made higher than the pressure at the end of the previous evacuation, so that the sterilization target object is evacuated each time the pressurized steam is introduced. By gradually increasing the heating degree and reducing the amount of decrease in the saturated steam temperature in the sterilization tank, it is possible to suppress the heat radiation from the object to be sterilized to the pressurized steam and simultaneously increase the temperature of the object to be sterilized. As a result, it is possible to uniformly preheat the center of the object to be sterilized.

Further, according to the invention described in claim 7, the air can be eliminated in a short time by adding the operation of eliminating the air by purging the sterilization tank with pressurized steam during the pretreatment step.

Further, according to the invention of claim 8,
When superheated steam is used as the pressurized steam, the amount of heat of the steam is increased, so that preheating can be effectively performed, and the difference in specific gravity with air becomes large, and air can be effectively removed. Further, by using the superheated steam, it is possible to suppress the condensation in the sterilization tank, take in the water adhering to the object to be sterilized into the superheated steam, and efficiently remove the water to raise the temperature. In addition, since water can be discharged outside the sterilization tank while being taken into the superheated steam, the degree of drying of the sterilized object can be increased.

Further, according to the invention of claim 9,
When the pressurized steam is discharged from the sterilization tank, the pressurized steam is condensed and discharged as condensed water while reducing the volume, whereby it can be efficiently discharged from the sterilization tank in a short time.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of a pressurized steam supply pattern in a method of operating a sterilizer according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a steam sterilizer to which the method for operating a sterilizer according to the present invention is applied.

FIG. 3 is a diagram for explaining a second embodiment of a pressurized steam supply pattern in the sterilizer operation method according to the present invention.

[Explanation of symbols]

 1 sterilization tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Takahashi 7 Horie-cho, Matsuyama-shi, Ehime Prefecture Miura Laboratory Co., Ltd.

Claims (9)

[Claims] 1. A sterilizer for performing a sterilization step after performing a pretreatment step of raising the temperature of an object to be sterilized in the sterilization tank 1 to a predetermined temperature and removing air in the sterilization tank 1. A method of operating a sterilizer, characterized in that a pressurized steam is introduced into and discharged from the sterilization tank 1 during a treatment process to remove air. 2. The pre-treatment process, wherein after introducing pressurized steam into the sterilization tank 1 to a predetermined pressure, this pressure is maintained for a certain period of time and then discharged.
The method for operating the sterilizer according to. 3. The method of operating a sterilizer according to claim 1, wherein introduction and discharge of pressurized steam are repeated a plurality of times during the pretreatment process. 4. When the introduction and discharge of pressurized steam are repeated a plurality of times during the pretreatment process, the pressure in the sterilization tank 1 is sequentially increased at the end of each introduction of pressurized steam. The method for operating the sterilizer according to claim 3, wherein 5. The pressure in the sterilization tank 1 is sequentially increased at the end of each discharge of the pressurized steam when the pressurized steam is repeatedly introduced and discharged a plurality of times during the pretreatment process. The method for operating the sterilizer according to claim 3, wherein 6. The pressure in the sterilization tank 1 at the end of each introduction of the pressurized steam is sequentially increased when the pressurized steam is repeatedly introduced and discharged a plurality of times during the pretreatment step, and The operating method of the sterilizer according to claim 3, wherein the pressure in the sterilization tank 1 at the end of each discharge of the pressurized steam is sequentially increased. 7. The operation according to claim 1, wherein the pretreatment step includes an operation of purging the sterilization tank 1 with pressurized steam to remove air. How to operate the sterilizer. 8. The method for operating a sterilizer according to claim 1, wherein the pressurized steam used in the pretreatment step is superheated steam. 9. The sterilizer according to claim 1, wherein when the pressurized steam is discharged during the pretreatment process, the pressurized steam is discharged while being condensed. how to drive.