JP2018011739A - Steam sterilization device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam sterilization device capable of quickly and surely drying an article to be sterilized after steam sterilization.SOLUTION: A device has a sterilization tank accommodating an article to be sterilized, pressure reducing means for reducing pressure in the sterilization tank, pressure restoring means for restoring pressure in the sterilization tank, steam supplying means for supplying steam to the sterilization tank, drain discharging means for discharging concentrated water of steam from the sterilization tank, air discharging means for discharging air in the sterilization tank to outside by a pressure difference from ambient pressure, and control means for controlling each means. The control means conducts a sterilization process a, an air discharging process b, and drying processes c to g in this order. In drying processes c to g, a blow drying operation g by opening a feed valve after repeating a pressure reduction operation c by the pressure reduction means and a pressure restoring process d by the pressure restoring means.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steam sterilization apparatus that vacuum-drys an object to be sterilized after steam sterilization.

  As is well known, a steam sterilization apparatus is an apparatus that supplies steam into a sterilization tank to sterilize the object to be sterilized, and then depressurizes the sterilization tank to dry the object to be sterilized. Conventionally, for this drying, as disclosed in Patent Document 1 below, continuous vacuum drying in which the inside of the sterilization tank is decompressed and held for a predetermined time, and pulse drying in which decompression and re-pressure by introduction of clean air are repeated are known. ing. Further, as disclosed in Patent Document 2 below, return pressure holding pulse drying that repeats decompression, return pressure by introducing clean air, and holding the return pressure state is also known.

JP 2001-204798 A (paragraph [0030], FIG. 2) JP 2002-95723 A (claim 2, paragraph [0020])

  However, in the prior art, any of continuous vacuum drying, pulse drying, and reverse pressure holding pulse drying is used alone. With only continuous vacuum drying, the temperature of the object to be sterilized cannot be increased by temporary re-pressure during the drying process, and there is room for improvement in promoting the drying of the object to be sterilized. On the other hand, in pulse drying, in particular, pressure retention pulse drying, the temperature of the object to be sterilized can be increased during the pressure retention, and the vacuum pump can be stopped during that time, so that drying can be promoted and running costs can be reduced. On the other hand, if the total drying time is the same as the continuous vacuum drying, the vacuum drying time due to the reduced pressure is substantially shortened only by the reverse pressure holding pulse drying, so that the object to be sterilized can be more reliably dried. desired.

  Then, the subject which this invention tends to solve is providing the steam sterilization apparatus which can dry the to-be-sterilized material after steam sterilization quickly and reliably.

  The present invention has been made to solve the above-mentioned problems. The invention according to claim 1 is directed to a sterilization tank in which an object to be sterilized is stored, and a gas in the sterilization tank is sucked and discharged to the outside. Depressurization means for depressurizing the inside of the sterilization tank, return pressure means for introducing outside air into the depressurized sterilization tank and restoring the pressure in the sterilization tank, steam supply means for supplying steam into the sterilization tank, A drain discharging means for discharging condensed water of steam from the inside of the sterilization tank, an exhaust means for discharging the gas in the sterilization tank to the outside by a differential pressure from the atmospheric pressure, and controlling each means, at least the sterilization A control means for sequentially executing a sterilization process for sterilizing an object to be sterilized in a tank with steam, an exhausting process for discharging steam from the sterilization tank, and a drying process for drying the object to be sterilized in the sterilization tank; Provided in the drying step. A steam sterilization apparatus which performs a blow drying operation by opening a supply valve into the sterilization tank by the decompression means after repeating the decompression operation and the decompression operation by the decompression means. is there.

  According to the first aspect of the present invention, in the drying step after the steam sterilization, after the pressure reducing operation by the pressure reducing means and the pressure returning operation by the pressure returning means are repeated, the air supply valve into the sterilization tank is opened. Perform blow drying operation. That is, after the pulse drying operation that repeats intermittent vacuum drying, the air supply valve is opened and the blow drying operation is performed. By the combination of drying operations, an object to be sterilized after steam sterilization can be quickly and reliably dried.

  The invention according to claim 2 is the steam sterilization apparatus according to claim 1, wherein the decompression means is operated during the blow drying operation.

  According to the second aspect of the present invention, when the blow drying operation is performed by opening the air supply valve after the pulse drying operation, the pressure reducing means is operated. Therefore, in the blow drying operation, the air introduced into the sterilization tank by the decompression means convects in the sterilization tank and is discharged by the decompression means, thereby promoting the drying of the object to be sterilized. Moreover, by performing aeration by a blow drying operation after the pulse drying operation, it is possible to reliably dry the object to be dried.

  According to a third aspect of the present invention, in the blow drying operation, the pressure reducing means is continuously operated for a set blow time while the air supply valve is open, and after the blow drying operation, the pressure reducing means is stopped and the pressure reducing means is stopped. The steam sterilization apparatus according to claim 1 or 2, wherein the inside of the sterilization tank is restored to atmospheric pressure by a restoring pressure means.

  According to the third aspect of the present invention, in the blow drying operation, the pressure reducing means is continuously operated for the set blow time while the air supply valve is opened. Meanwhile, the air introduced into the sterilization tank by the return pressure means convects in the sterilization tank and is discharged by the pressure reduction means, thereby promoting the drying of the sterilized object. Moreover, by performing aeration by a blow drying operation after the pulse drying operation, it is possible to reliably dry the object to be dried. Then, after the blow drying operation, the decompression means can be stopped and the inside of the sterilization tank can be decompressed to atmospheric pressure by the decompression means.

  According to a fourth aspect of the present invention, the control means, after repeating the decompression operation and the decompression operation in the drying step, performs a final vacuum operation, and then proceeds to the blow drying operation. In the final vacuum operation, with the air supply valve closed, the sterilization tank is continuously depressurized for a set depressurization time by the depressurization means, or is depressurized to a set depressurization pressure. It is a steam sterilization apparatus given in any 1 paragraph.

  According to the fourth aspect of the invention, after the pulse drying operation, the final vacuum operation is performed, and then the blow drying operation is performed. In the final vacuum operation, it is more reliable than the decompression operation during the pulse drying operation by keeping the sterilization tank decompressed for the set decompression time by the decompression means with the air supply valve closed or by reducing the pressure to the set decompression pressure. Stable vacuum drying can be achieved. By performing such a final vacuum operation after the pulse drying operation and further performing a blow drying operation, the material to be sterilized can be further reliably dried.

  According to a fifth aspect of the present invention, when the pressure reduction operation and the pressure recovery operation are repeated, after the pressure recovery operation, the pressure recovery state is maintained for a set holding time and then the pressure reduction operation is performed. Item 5. The steam sterilizer according to any one of Items 1 to 4.

  According to the fifth aspect of the present invention, in the pulse drying operation, when the decompression operation and the decompression operation are repeated, the decompression operation is started after the decompression operation is held for the set holding time after the decompression operation. That is, the decompression operation, the return pressure operation, and the holding operation after the return pressure are repeated (return pressure holding pulse drying operation). While maintaining the return pressure, the surface temperature of the object to be sterilized can be increased, and the subsequent vacuum drying can be effectively achieved by the decompression operation. Further, in the decompression operation and the holding operation, the decompression means can be stopped (or the output can be reduced), and the running cost of the decompression means (typically, the electricity bill and water bill of the water ring vacuum pump) can be reduced. . In the following description, the pulse drying operation and the return pressure holding pulse drying operation may be simply referred to as pulse drying operation unless otherwise specified.

  The invention according to claim 6 is the steam sterilization according to claim 4, wherein the pressure reduction by the final vacuum operation is lower than the pressure reduction by the pressure reduction operations, the ultimate pressure when viewed in absolute pressure. Device.

  According to the invention described in claim 6, since the degree of vacuum in the final vacuum operation is higher than the degree of vacuum in each decompression operation in the pulse drying operation (that is, the absolute pressure is lowered), drying by the final vacuum operation is further ensured. Can be aimed at.

  In the seventh aspect of the present invention, the repetition condition of each operation including the decompression operation and the return pressure operation is a lapse of a set time, and each of the operations including the decompression operation and the return pressure operation is performed. The steam sterilization apparatus according to any one of claims 1 to 6, wherein when the end condition is satisfied during the repetition of the operation, the repetition is ended even if any operation is being executed.

  According to the seventh aspect of the present invention, the pulse drying operation is executed for a set time, and when this set time elapses, the pulse drying operation is ended regardless of the operation content being executed. Therefore, it is easy to maintain the total operation time of the steam sterilizer at a predetermined level.

  The invention according to claim 8 is the steam sterilization apparatus according to any one of claims 1 to 7, wherein in the return pressure operation, the air supply valve is maintained in an open state.

  According to the eighth aspect of the present invention, the internal pressure of the sterilization tank can be restored to atmospheric pressure by maintaining the air supply valve in the open state when the pressure is restored in the pulse drying operation.

  The invention according to claim 9 is characterized in that, in the return pressure operation, the supply valve is closed when the inside of the sterilization tank reaches a return pressure target pressure set at less than atmospheric pressure. 9. The steam sterilizer according to any one of 8 above.

  According to the ninth aspect of the present invention, when the return pressure in the pulse drying operation is reached, the supply valve is closed when the return pressure target pressure set at less than atmospheric pressure is reached. By not returning to atmospheric pressure, the load of the next decompression operation is reduced, and the running cost of the decompression means can be reduced.

  The invention described in claim 10 includes a pressure sensor for monitoring the pressure in the sterilization tank, and performs the pressure-reducing operation and the pressure-reducing operation based on the pressure detected by the pressure sensor. It is a steam sterilizer of any one of 1-9.

  According to the invention described in claim 10, the pulse drying operation can be easily and reliably performed by pressure control.

  The invention according to claim 11 is the steam sterilization apparatus according to claim 10, wherein the pressure sensor measures pressure as an absolute pressure.

  According to the eleventh aspect of the present invention, stable and reliable operation with high reproducibility can be performed without being influenced by atmospheric pressure fluctuations by controlling using the absolute pressure sensor.

  According to the steam sterilization apparatus of the present invention, an object to be sterilized after steam sterilization can be quickly and reliably dried.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the steam sterilization apparatus of one Example of this invention, and shows a part in cross section. It is the schematic which shows the 1st pattern of the drying process of the steam sterilizer of FIG. 1, and has shown the relationship between the pressure in a sterilization tank, and elapsed time. It is the schematic which shows the 2nd pattern of the drying process of the steam sterilizer of FIG. 1, and has shown the relationship between the pressure in a sterilization tank, and elapsed time.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a steam sterilization apparatus 1 according to an embodiment of the present invention, and a part thereof is shown in cross section.

  The steam sterilization apparatus 1 according to the present embodiment includes a sterilization tank 2 in which an object to be sterilized is stored, a decompression unit 3 that sucks and discharges the gas in the sterilization tank 2 to the outside, and decompresses the sterilization tank 2. Introducing outside air into the sterilization tank 2 to restore the pressure in the sterilization tank 2, a steam supply means 5 for supplying steam into the sterilization tank 2, and discharging condensed water of steam from the sterilization tank 2 A drain discharging means 6 for discharging the gas in the sterilization tank 2 to the outside by a pressure difference from the atmospheric pressure, and a control means (not shown) for controlling these means 3 to 7.

  The article to be sterilized is not particularly limited, but is typically a medical instrument. The article to be sterilized may be accommodated in a sterilization bag, non-woven fabric, sterilization container, or the like, if desired. The article to be sterilized is placed on a shelf in the sterilization tank 2 or placed on a carriage and accommodated in the sterilization tank 2 together with the carriage.

  The sterilization tank 2 is a hollow container that can withstand pressure reduction and pressurization of the internal space, and is typically formed in a substantially rectangular box shape. The sterilization tank 2 of the present embodiment is provided with a door (not shown) for taking in and out the article to be sterilized on the front side (the front side perpendicular to the paper surface of FIG. 1). However, each door is provided with a front door and a rear door, and one door is used as a carry-in door for putting a material to be sterilized into the sterilization tank 2 and the other door is sterilized after sterilization outside the sterilization tank 2. It is good also as a carrying-out door for taking out an object. In any case, the opening of the sterilization tank 2 can be hermetically closed by closing the door. That is, the gap between the sterilization tank 2 and the door is sealed with packing (not shown).

  In order to warm the inside of the sterilization tank 2 from the outside, a steam jacket 8 is provided on the outer wall of the sterilization tank 2 in this embodiment. Specifically, the steam sterilization apparatus 1 includes an inner can 9 and an outer can 10, and the inner can 9 forms the sterilization tank 2, and a gap between the inner can 9 and the outer can 10 serves as a steam jacket 8. The In the present embodiment, the steam jacket 8 is continuously provided on each of the upper, lower, left and right walls of the sterilization tank 2. Steam is supplied to the steam jacket 8 via a jacket steam supply path (not shown), and the condensed water of the steam is discharged to the outside via a jacket drain discharge path (not shown). By controlling the supply of steam into the steam jacket 8 so as to maintain the inside of the steam jacket 8 at a predetermined pressure, the inside of the sterilization tank 2 can be heated from the outside at a predetermined temperature.

  The decompression means 3 sucks and discharges the gas in the sterilization tank 2 to the outside through the vacuum exhaust path 11. A vacuum valve 12, a water-sealed vacuum pump 13, and a check valve 14 are sequentially provided in the vacuum exhaust path 11 from the sterilization tank 2. Further, a heat exchanger for vapor condensation may be provided in the vacuum exhaust path 11 between the vacuum valve 12 and the vacuum pump 13. By opening the vacuum valve 12 and operating the vacuum pump 13, the gas in the sterilization tank 2 can be sucked and discharged outside, and the inside of the sterilization tank 2 can be decompressed.

  The return pressure means 4 introduces outside air into the sterilization tank 2 under reduced pressure via an air supply path 15. An air filter 16, an air supply valve 17, and a check valve 18 are sequentially provided in the air supply path 15 into the sterilization tank 2. However, the installation order of the air supply valve 17 and the check valve 18 may be switched. When the air supply valve 17 is opened while the inside of the sterilization tank 2 is depressurized, outside air can be introduced into the sterilization tank 2 by the differential pressure, and the inside of the sterilization tank 2 can be restored. At that time, clean air is introduced into the sterilization tank 2 by the air filter 16. If the air supply valve 17 is configured so that the opening degree can be adjusted, the return pressure in the sterilization tank 2 can be gradually increased.

  The steam supply means 5 supplies steam (saturated steam) into the sterilization tank 2 through the steam supply path 19. A steam supply valve 20 is provided in the steam supply path 19. By opening the steam supply valve 20, steam from a steam supply source (not shown) can be supplied into the sterilization tank 2. The presence / absence or amount of steam supplied into the sterilization tank 2 can be changed by controlling the opening / closing or opening of the steam supply valve 20.

  The drain discharge means 6 discharges steam condensed water from the sterilization tank 2 through the drain discharge path 21. In the drain discharge path 21 from the inside of the sterilization tank 2, a steam trap 22 and a check valve 23 are sequentially provided. While supplying steam into the sterilization tank 2 by the steam supply means 5, the condensed water of the steam is discharged out of the sterilization tank 2 by the drain discharge means 6.

  The exhaust means 7 derives gas from the sterilization tank 2 under pressure through the exhaust path 24. An exhaust valve 25 and a check valve 26 are sequentially provided in the exhaust path 24 from the inside of the sterilization tank 2. If the exhaust valve 25 is opened while the inside of the sterilization tank 2 is pressurized, the gas in the sterilization tank 2 can be led out to the outside by the differential pressure, and the pressure in the sterilization tank 2 can be lowered. In the illustrated example, the exhaust passage 24 is a common conduit with the drain discharge passage 21 on the upstream side (sterilization tank 2 side).

  The sterilization tank 2 is provided with a pressure sensor 27 that detects the pressure in the sterilization tank 2 and a temperature sensor 28 that detects the temperature in the sterilization tank 2. Although the installation position of the pressure sensor 27 is not particularly limited, for example, it is provided on the upper side portion of the sterilization tank 2 as in the illustrated example. On the other hand, the temperature sensor 28 is provided at a predetermined position in accordance with various standards regarding sterilization. In the example of illustration, it is provided in the exit part from the sterilization tank 2 among the said common pipe lines (common pipe line of the drain discharge path 21 and the exhaust path 24).

  The control means is a controller (not shown) that controls the means 3 to 7 based on the detection signals of the sensors 27 and 28, the elapsed time, and the like. Specifically, the vacuum valve 12, the vacuum pump 13, the air supply valve 17, the steam supply valve 20, the exhaust valve 25, the pressure sensor 27, the temperature sensor 28, and the like are connected to a controller. Then, as described below, the controller performs sterilization of the sterilized material in the sterilization tank 2 and subsequent drying in accordance with a predetermined procedure (program).

Hereinafter, the specific example of the operating method of the steam sterilizer 1 of a present Example is demonstrated.
The steam sterilizer 1 typically executes a preheating process, a pretreatment process, a sterilization process, an exhaust process, and a drying process sequentially. Hereinafter, each step will be described. In the initial state, the air supply valve 17 and the exhaust valve 25 are open, while the other valves 12 and 20 are closed and the vacuum pump 13 is stopped. During or before or after the preheating step, an object to be sterilized is accommodated in the sterilization tank 2, and the door of the sterilization tank 2 is airtightly closed. At that time, the air supply valve 17 and the exhaust valve 25 are also closed.

  In the preheating step, the inside of the sterilization tank 2 is heated. Specifically, steam is supplied into the steam jacket 8 and the inside of the steam jacket 8 is maintained at a predetermined pressure, whereby the inside of the sterilization tank 2 is heated to a predetermined temperature and maintained. The pretreatment process is started after a lapse of a predetermined time from the start of the preheating process, and the content of the preheating process is continuously performed in each subsequent process.

  In the pretreatment process, air is excluded from the sterilization tank 2. Specifically, the inside of the sterilization tank 2 is depressurized by the depressurizing means 3, and at that time, steaming by the steaming means 5 may be accompanied. Further, after the pressure inside the sterilization tank 2 is once reduced by the pressure reducing means 3, the steaming by the steaming means 5 and the pressure reducing by the pressure reducing means 3 may be repeated. When pressurizing the inside of the sterilization tank 2, the steam supply by the steam supply means 5 and the exhaust by the exhaust means 7 may be repeated. In any case, after exhausting air from the inside of the sterilization tank 2, finally, the inside of the sterilization tank 2 is increased to the sterilization pressure by steaming by the steaming means 5. Then, when the temperature detected by the temperature sensor 28 reaches the sterilization temperature or the pressure detected by the pressure sensor 27 reaches the sterilization pressure, the process proceeds to the next step.

  In the sterilization process, an object to be sterilized in the sterilization tank 2 is sterilized with steam. Specifically, the steam supply means 5 is controlled so that the temperature detected by the temperature sensor 28 maintains the sterilization temperature (typically 121 ° C. or 135 ° C.), and the sterilization tank 2 is maintained by holding the sterilization time. Sterilize the items to be sterilized. Alternatively, an object to be sterilized in the sterilization tank 2 is controlled by controlling the steam supply means 5 and maintaining the sterilization time so that the detected pressure of the pressure sensor 27 maintains the sterilization pressure (saturated steam pressure corresponding to the sterilization temperature). Sterilize. Thereafter, the steaming by the steaming means 5 is stopped and the process proceeds to the next step.

  In the exhaust process, steam is discharged from the sterilization tank 2 under pressure, and the pressure in the sterilization tank 2 is reduced to near atmospheric pressure. Specifically, the exhaust valve 25 is opened and the steam is led out of the sterilization tank 2. When the set exhaust time elapses from the opening of the exhaust valve 25 or when the pressure in the sterilization tank 2 falls to the set exhaust pressure (atmospheric pressure or slightly higher pressure), the exhaust valve 25 is closed and the process proceeds to the next step. .

  In the drying process, an object to be sterilized in the sterilization tank 2 is dried. Specifically, the object to be sterilized in the sterilization tank 2 is dried by operating vacuuming from the sterilization tank 2 by the decompression means 3 and introducing clean air into the sterilization tank 2 by the decompression means 4. Specific drying methods include each pattern described below, and the drying process is performed in any one of the patterns. Then, after the object to be sterilized is dried, the decompression means 3 is stopped, while the decompression means 4 restores the pressure in the sterilization tank 2 to atmospheric pressure, and the series of operations ends. Hereinafter, each pattern of a drying process is demonstrated.

≪First pattern≫
FIG. 2 is a schematic diagram showing a first pattern of the drying process of the steam sterilizer 1, and shows the relationship between the pressure P in the sterilization tank 2 and the elapsed time t. In addition, in FIG. 2, it has illustrated from the last stage of the sterilization process a, and after the sterilization process a, the exhaust process b is made | formed, and drying process cg is made after that. In FIG. 2, P0 represents atmospheric pressure (0 MPaG).

  In the drying step, first, each operation of the decompression operation c by the decompression means 3, the decompression operation d by the decompression means 4, and the holding operation e in the decompressed state is repeated until a predetermined end condition is satisfied (FIG. 2 cf). Here, the end condition is the elapse of a set time (typically, the elapse of the set time from the start of the drying process, that is, the start of the repetition of each operation). And the return pressure operation d and the holding operation e may be set as the end condition.

  In the decompression operation c, the interior of the sterilization tank 2 is decompressed by the decompression means 3 until the decompression target pressure is reached with the air supply valve 17 closed. However, the decompression means 3 may be operated for the set decompression time. Even in this case, the set decompression time is set so that the inside of the sterilization tank 2 is substantially at the decompression target pressure.

  In the return pressure operation d, the inside of the sterilization tank 2 is returned by the return pressure means 4 with the pressure reducing means 3 stopped. Typically, the inside of the sterilization tank 2 is at or near the atmospheric pressure (when the absolute pressure is taken into consideration when the atmospheric pressure outside the sterilization tank 2 is considered, it is usually about 80 to 110 kPaA, but of course the actual atmospheric pressure is restored to the maximum. The pressure is restored to the pressure limit. At this time, the air supply valve 17 may be maintained in an open state, and the inside of the sterilization tank 2 may be returned to atmospheric pressure, or the air supply valve 17 may be closed in the middle of the recovery and the inside of the sterilization tank 2 may be returned to atmospheric pressure. The return pressure may be reduced to a return pressure target pressure below. That is, during the return pressure in the sterilization tank 2 due to the opening of the air supply valve 17, the detected pressure of the pressure sensor 27 is monitored, and when the pressure reaches the return pressure target pressure lower than the atmospheric pressure, the air supply valve 17 is turned off. It may be closed. In the present embodiment, during the pressure-reducing operation d, the vacuum valve 12 is closed and the vacuum pump 13 is stopped. However, in some cases, the number of rotations of the vacuum pump 13 can be reduced with the vacuum valve 12 opened, The opening degree of the vacuum valve 12 may be reduced. Further, during the return pressure operation d, the opening degree of the air supply valve 17 may be adjusted to gradually return the pressure in the sterilization tank 2 (return pressure speed adjustment).

  In the holding operation e, the return pressure state by the return pressure operation d is held for a set holding time (for example, 1 to 5 minutes). In the return pressure operation d, when the air supply valve 17 is maintained in the open state, after the pressure inside the sterilization tank 2 is returned to the atmospheric pressure by the return pressure operation d, the air supply valve 17 is kept open and the atmospheric pressure is set as the holding operation e. It is only necessary to hold for the set holding time. Alternatively, in the return pressure operation d, when the supply valve 17 is closed due to the return pressure target pressure set at less than atmospheric pressure, the supply valve 17 is set as the holding operation e while the supply valve 17 is closed. It is only necessary to hold the set holding time after closing.

  Thereafter, the operation returns to the decompression operation c and the same operation may be repeated. That is, the decompression operation c, the decompression operation d, and the holding operation e may be repeated until a predetermined end condition is satisfied (here, the set time has elapsed) (reference characters cf in FIG. 2). However, during this repetition, the holding operation e can be omitted in some cases. In that case, the decompression operation c and the decompression operation d are repeated. That is, in the return pressure operation d, after the inside of the sterilization tank 2 is returned to the desired pressure, the next pressure reduction operation c is executed without maintaining the return pressure state.

  The repetition of each operation including the decompression operation c and the decompression operation d is referred to as a pulse drying operation. At that time, the case where the holding operation e is included is particularly distinguished from the case where the holding operation e is not included. In the pulse drying operations c to f, the pressure reduction target pressures (or the set pressure reduction times) of the pressure reduction operations c are typically the same as each other, but may be different depending on circumstances. Similarly, in the pulse drying operations c to f, the return pressure target pressures of the return pressure operations d and the set holding times of the holding operations e are typically the same as each other, but may differ depending on the case. Also good.

  As described above, in this embodiment, the pulse drying operations c to f are executed for a set time. When the set time elapses during the pulse drying operations c to f, the pulse drying operations c to f are performed regardless of the operation contents being executed. It is good to end f. That is, when the set time elapses, it is preferable to stop the pulse drying operations c to f and stop the execution of any of the decompression operation c, the decompression operation d, and the holding operation e. At that time, the operation being executed when the set time elapses (for example, the pressure reducing operation if the pressure reducing operation c is in progress) may be terminated immediately during the execution, or only the operation being executed is completed before the next blow. You may transfer to the drying operation g. In any case, when the set time elapses during the pulse drying operations c to f, the total operation time of the steam sterilizer 1 is reduced by ending the pulse drying operations c to f regardless of the operation content being executed. Easy to maintain in place.

  According to such pulse drying operations c to f, the object to be sterilized can be dried by repeating the decompression in the sterilization tank 2 and the return pressure by introducing clean air. Further, in the return pressure operation d and the holding operation e, by introducing air into the sterilization tank 2, the heating from the steam jacket 8 to the object to be sterilized is promoted, and the surface temperature of the object to be sterilized can be increased. Therefore, it is possible to effectively achieve vacuum drying by the subsequent decompression operation c. Further, in the decompression operation d and the holding operation e, the decompression means 3 is stopped (or the output is reduced), thereby reducing the running cost of the decompression means 3 (the electricity bill and the water bill for the water-sealed vacuum pump 13). be able to.

  After completing the pulse drying operations c to f, the air supply valve 17 is opened to perform the blow drying operation g. In the blow drying operation g, typically, the pressure reducing means 3 is continuously operated for the set blow time while the air supply valve 17 is opened. Meanwhile, the air introduced into the sterilization tank 2 by the decompression means 4 convects in the sterilization tank 2 and is discharged by the decompression means 3, so that the object to be sterilized can be promoted to dry. Moreover, after the pulse drying operations c to f, the material to be dried can be reliably dried by aeration by the blow drying operation g. Then, after the blow drying operation g, the decompression means 3 is stopped, and the inside of the sterilization tank 2 is decompressed to atmospheric pressure by the decompression means 4 (symbol h in FIG. 2).

  By the way, during the series of drying steps c to g described above, the pulse drying operation (specifically, the decompression operation c and the decompression operation d) can be easily and reliably controlled based on the pressure detected by the pressure sensor 27. it can. At this time, as the pressure sensor 27, a pressure sensor that measures a gauge pressure may be used, or a pressure sensor that measures an absolute pressure may be used. By using the pressure sensor 27 that measures the pressure as the absolute pressure, the operation becomes uniform each time without being influenced by fluctuations in the atmospheric pressure, and a stable and reliable operation with high reproducibility can be performed. That is, in the pressure reduction operation c, the absolute pressure can be reduced to a predetermined pressure reduction target pressure, and in the return pressure operation d, the absolute pressure can be returned to a predetermined return pressure target pressure. At that time, the return pressure target pressure can be set so as to always stop at the return pressure of less than atmospheric pressure in the return pressure operation d regardless of the atmospheric pressure fluctuation outside the sterilization tank 2. Such control based on the absolute pressure is not limited to the drying process, and may be performed in other processes depending on circumstances.

≪Second pattern≫
FIG. 3 is a schematic diagram showing a second pattern of the drying process of the steam sterilizer 1, and shows the relationship between the pressure P in the sterilization tank 2 and the elapsed time t. In addition, in FIG. 3, it has illustrated from the last stage of the sterilization process a, and after the sterilization process a, the exhaust process b is made | formed, and drying process cf, i is made after that. In FIG. 3, P0 indicates atmospheric pressure (0 MPaG).

  The second pattern is basically the same as the first pattern. Therefore, below, it demonstrates centering around a different point and both description is abbreviate | omitted. Further, portions corresponding to both patterns will be described with the same reference numerals.

  Even in the second pattern, first, a pulse that repeats each of the decompression operation c by the decompression unit 3, the decompression operation d by the decompression unit 4, and the holding operation e in the decompressed state until a predetermined end condition is satisfied. Drying operations c to f are performed. At this time, as with the first pattern, the holding operation e can be omitted, and in this case, the decompression operation c and the decompression operation d are repeated.

  After the completion of the pulse drying operations c to f, a final vacuum operation i for reducing the pressure in the sterilization tank 2 is performed. In the final vacuum operation i, the sterilization tank 2 is continuously depressurized for the set depressurization time by the depressurization means 3 while the supply valve 17 is closed, or depressurized to the set depressurization pressure. At this time, the degree of vacuum in the sterilization tank 2 is increased to the maximum (that is, the absolute pressure can be reduced as much as possible) so that the capacity of the decompression means 3 can be exhibited to the limit (attainment pressure). As described above, a set decompression time or a set decompression pressure may be set. Alternatively, the set depressurization time and the set depressurization pressure may be set so as to depressurize to a pressure having a margin slightly beyond the capacity limit of the depressurization means 3.

  In any case, the pressure reduction by the final vacuum operation i is preferably lower than the pressure reduction by the pressure reduction operations c in the pulse drying operations c to f when viewed in absolute pressure. By making the degree of vacuum of the final vacuum operation i higher than the degree of vacuum of each decompression operation c in the pulse drying operations c to f (that is, lowering the absolute pressure), drying by the final vacuum operation i can be further ensured. it can. After the final vacuum operation i, the decompression means 3 is stopped, and the inside of the sterilization tank 2 is decompressed to atmospheric pressure by the decompression means 4 (symbol h in FIG. 3).

  By the way, in the second pattern, similarly to the first pattern, the pulse drying operation (specifically, the decompression operation c and the decompression operation d) and the final vacuum operation i are performed by the pressure sensor 27 during the series of drying processes described above. Based on the detected pressure, it can be easily and reliably controlled. At this time, as the pressure sensor 27, a pressure sensor that measures a gauge pressure may be used, or a pressure sensor that measures an absolute pressure may be used. By using the pressure sensor 27 that measures the pressure as the absolute pressure, it is possible to perform a stable and reliable operation with high reproducibility without being influenced by atmospheric pressure fluctuations.

≪Third pattern≫
The third pattern is a combination of the first pattern and the second pattern. Here, the final vacuum operation i of the second pattern is performed between the pulse drying operations c to f of the first pattern and the blow drying operation g. In other words, the blow drying operation g of the first pattern is performed after the pulse drying operations c to f of the second pattern and the final vacuum operation i.

  Specifically, in the third pattern, the pulse drying operations c to f, the final vacuum operation i, and the blow drying operation g are sequentially performed. At this time, the pulse drying operations cf of the third pattern are the same as the pulse drying operations cf of the first pattern and the second pattern, and the final vacuum operation i of the third pattern is the final vacuum of the second pattern. The third pattern blow drying operation g is the same as the operation i, and the third pattern blow drying operation g is the same as the first pattern blow drying operation g. By performing the final vacuum operation i after the pulse drying operations c to f, it is possible to reliably perform vacuum drying with an increased degree of vacuum, and then perform the blow drying operation g to dry the object to be sterilized by aeration. it can.

  The steam sterilization apparatus 1 of the present invention is not limited to the configuration (including control) of the above embodiment, and can be changed as appropriate. In particular, the sterilization tank 2, the decompression means 3, the decompression means 4, the steam supply means 5, the drain discharge means 6, the exhaust means 7 and the control means are provided, and the control means sequentially performs at least a sterilization process, an exhaust process and a drying process. In the drying process, after the decompression operation c by the decompression means 3 and the decompression operation d by the decompression means 4 are repeated, the air supply valve 17 into the sterilization tank 2 by the decompression means 4 is opened. If the blow drying operation g is performed, other structures can be appropriately changed.

  For example, the drying process of the above embodiment may include operations other than the pulse drying operations c to f, the blow drying operation g, and the final vacuum operation i. As an example, in each pattern of the drying process, the pressure in the sterilization tank 2 may be reduced as an initial vacuum operation before the pulse drying operations c to f. As in the final vacuum operation, the initial vacuum operation is performed by reducing the pressure by the decompression means 3 for the set decompression time with the air supply valve 17 closed, or after reducing the pressure to the set decompression pressure, the decompression means 3 is stopped. In this operation, the air supply valve 17 is opened to return the pressure to atmospheric pressure or the vicinity thereof. Note that the set decompression time and set decompression pressure for the initial vacuum operation may be the same as or different from the set decompression time and set decompression pressure for the final vacuum operation i.

DESCRIPTION OF SYMBOLS 1 Steam sterilizer 2 Sterilization tank 3 Pressure reducing means 4 Pressure reducing means 5 Steam supply means 6 Drain discharge means 7 Exhaust means 8 Steam jacket 9 Inner can 10 Outer can 11 Vacuum exhaust path 12 Vacuum valve 13 Vacuum pump 14 Check valve 15 Supply Air path 16 Air filter 17 Air supply valve 18 Check valve 19 Steam supply path 20 Steam supply valve 21 Drain discharge path 22 Steam trap 23 Check valve 24 Exhaust path 25 Exhaust valve 26 Check valve 27 Pressure sensor 28 Temperature sensor a Sterilization Step b Exhaust step c Depressurization operation d Restoring operation e Holding operation f Repeating c to d g Blow drying operation i Final vacuum operation

Claims (11)

A sterilization tank in which objects to be sterilized are stored;
Decompression means for sucking and discharging the gas in the sterilization tank to the outside and decompressing the sterilization tank;
Return pressure means for introducing outside air into the sterilized tank that has been depressurized to restore the pressure in the sterilization tank;
Steaming means for supplying steam into the sterilization tank;
Drain discharge means for discharging steam condensate from the sterilization tank;
An exhaust means for discharging the gas in the sterilization tank to the outside by a differential pressure from the atmospheric pressure;
By controlling each of the means, at least a sterilization step of sterilizing the sterilization object in the sterilization tank with steam, an exhausting process of discharging the steam from the sterilization tank, and drying the sterilization object in the sterilization tank Control means for sequentially executing the drying process,
In the drying step, the control means repeats the decompression operation by the decompression means and the return pressure operation by the decompression means, and then opens the air supply valve into the sterilization tank by the decompression means to blow. A steam sterilizer that performs a drying operation. The steam sterilizer according to claim 1, wherein the decompression unit is operated during the blow drying operation. In the blow drying operation, the decompression means continues to operate for a set blow time while the air supply valve is open,
3. The steam sterilization apparatus according to claim 1, wherein after the blow drying operation, the decompression unit is stopped, and the inside of the sterilization tank is decompressed to atmospheric pressure by the decompression unit. In the drying process, the control means repeats the pressure reduction operation and the pressure recovery operation, and then performs a final vacuum operation, and then proceeds to the blow drying operation.
In the final vacuum operation, the sterilization tank is continuously depressurized for a set depressurization time by the depressurization means with the air supply valve closed, or is depressurized to a set depressurization pressure. The steam sterilizer according to any one of the above. 5. When the pressure reduction operation and the pressure recovery operation are repeated, the pressure reduction state is maintained after the pressure recovery operation for a set holding time, and then the pressure reduction operation is performed. 5. The steam sterilizer described in 1. The steam sterilization apparatus according to claim 4, wherein the pressure reduction by the final vacuum operation is lower in ultimate pressure when viewed in absolute pressure than the pressure reduction by each of the pressure reduction operations. An end condition of repetition of each operation including the decompression operation and the decompression operation is the passage of a set time,
7. The repetition of the operation according to claim 1, wherein when the end condition is satisfied during the repetition of each operation including the decompression operation and the decompression operation, the repetition is ended even if any operation is being performed. The steam sterilizer according to any one of the above. The steam sterilizer according to any one of claims 1 to 7, wherein, in the return pressure operation, the air supply valve is maintained in an open state. 9. The return valve according to claim 1, wherein in the return pressure operation, the supply valve is closed when the inside of the sterilization tank reaches a return pressure target pressure set at less than atmospheric pressure. Steam sterilizer. A pressure sensor for monitoring the pressure in the sterilization tank;
The steam sterilization apparatus according to any one of claims 1 to 9, wherein the decompression operation and the decompression operation are performed based on a pressure detected by the pressure sensor. The steam sterilizer according to claim 10, wherein the pressure sensor measures a pressure as an absolute pressure.

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