WO2018025432A1 - Air leakage detection device and steam sterilizer equipped with same - Google Patents

Abstract

The present invention is used for a steam sterilizer (2) in which after purging a sterilization tank (3) of air, steam is fed into the sterilization tank (3) to sterilize an object to be sterilized inside the sterilization tank (3). A heat exchanger (30) is disposed outside the sterilization tank (3) and has: a hollow part (32) which is connected to the interior of the sterilization tank (3); and a liquid passage part (33) for causing a liquid to exchange heat with a fluid within the hollow part (32). A determination means determines the presence/absence of air leakage into the sterilization tank (3) or determines an amount of the air leakage on the basis of the inlet temperature, outlet temperature, and flow rate of the liquid in the liquid passage part (33). The hollow part (32) of the heat exchanger (30) has one end thereof connected to the sterilization tank (3), and has the other end provided with a protruded part (34) that protrudes outward from the liquid passage part (33). During a sterilization process, air remaining uncondensed within the heat exchanger (30) is pushed out to the protruded part (34).

Description

Air leak detector and steam sterilizer equipped with the same

The present invention relates to an air leak detection device for confirming the presence or amount of air leak into a sterilization tank of a steam sterilization device, and a steam sterilization device equipped with the air leak detection device. This application claims priority based on Japanese Patent Application No. 2016-152449 for which it applied to Japan on August 3, 2016, and uses the content here.

As is well known, a steam sterilization apparatus is an apparatus that sterilizes an object to be sterilized in steam with a saturated steam atmosphere in a sterilization tank. Therefore, if an air leak into the sterilization tank (air inflow from the outside into the sterilization tank) occurs, the inside of the sterilization tank cannot be maintained in a saturated steam atmosphere, and the intended sterilization may not be achieved.

Conventionally, a leak test is performed before operation in order to confirm in advance whether there is an air leak in the sterilization tank (more specifically, whether there is an air leak exceeding the reference value). Specifically, the inside of the sterilization tank is once decompressed and held, and the presence or absence of air leaks is confirmed by monitoring the pressure increase during that time.

JP 2000-237287 A

However, air leaks that occur during operation (that is, during steam sterilization) cannot be detected only by performing a leak test prior to operation as in the prior art. For example, the steam sterilization apparatus is designed to exclude air from the sterilization tank in the pretreatment process with decompression in the sterilization tank after the start of operation, but when the pressure in the sterilization tank is reduced in this pretreatment process, Air may flow into the sterilization tank from the outside. Further, in order to seal the gap between the sterilization tank and the door, the packing may be pressed against the door with pressurized air (for example, Patent Document 1 above), but the pressure of the pressurized air is higher than the pressure in the sterilization tank. Since it is high, the pressurized air leaking from the packing groove may flow into the sterilization tank. In the prior art, such an air leak during operation cannot be detected.

On the other hand, the applicant has proposed an air leak detection device capable of detecting an air leak occurring during operation and has already filed a patent application (Japanese Patent Application No. 2015-215403). As shown in FIG. 6, this apparatus includes a heat exchanger 30 having a double tube structure of an inner tube 35 and an outer tube 36, and the hollow hole of the inner tube 35 communicates with the inside of the sterilization tank, Water is passed through the cylindrical space between the outer tube 36 as the liquid passing portion 33. Typically, the heat exchanger 30 is arranged along the vertical direction of the axis of each of the tubes 35 and 36, and water is passed through the liquid passage portion 33 from below to above at a set flow rate. An inlet temperature sensor 46 is provided at the water supply port to the heat exchanger 30, while an outlet temperature sensor 47 is provided at the drain port from the heat exchanger 30. Then, the presence or absence of air leak into the sterilization tank is determined based on the temperature difference between the temperature sensors 46 and 47, that is, the temperature difference between the water outlet temperature and the inlet temperature with respect to the liquid passage portion 33. That is, in the heat exchanger 30, by utilizing the fact that the vapor is condensed but the air is not condensed, if there is an air leak, the temperature difference is difficult to occur, and the occurrence of the air leak can be detected.

However, in the case of a steam sterilizer, there are cases in which the sterilization temperature (in other words, sterilization is performed in a saturated steam atmosphere as described above, in other words, sterilization pressure) is changed to operate. For example, there is a case where either one of standard sterilization at 121 ° C. (205 kPaA) and high-temperature sterilization at 135 ° C. (313 kPaA) is selected for operation. When the sterilization temperature is changed, the pressure in the sterilization tank and hence the inner pipe 35 also changes, so that the degree of compression of air in the inner pipe 35 varies.

Specifically, in FIG. 6, (A) shows the case where the sterilization temperature is 121 ° C., (B) shows the case where the sterilization temperature is 135 ° C. (High part). Of course, in practice, steam and air are mixed in the inner pipe 35, and air accumulates so that the air concentration (also referred to as air partial pressure) increases as it goes upward. Accordingly, the shaded portion in the drawing can be said to be a portion where the air concentration is higher than a predetermined value, and this is shown as an air reservoir.

In addition, the reason why such an air pocket occurs is as follows. That is, first, in the heat exchanger 30 of the air leak detection device, steam is supplied from inside the sterilization tank, but the steam is cooled and condensed by passing water in the heat exchanger 30, and the condensed water drops downward. . At this time, if air is mixed in the vapor from the inside of the sterilization tank, the air remains without being condensed. Then, due to the flow of steam from the inside of the sterilization tank to the heat exchanger 30, the air mixed in the saturated steam becomes trapped in the heat exchanger 30, and in the heat exchanger 30, the air concentration increases with time. Gradually rises. In this way, the air concentration increases as it goes above the inner tube 35. And the raise of the air concentration in the heat exchanger 30 will reduce a condensation heat transfer coefficient.

Thus, when an air leak occurs during steam sterilization in the sterilization tank, air gradually accumulates in the upper part of the inner pipe 35. However, as can be seen by comparing FIGS. 4A and 4B, even if the amount of air is the same, the pressure is different if the sterilization temperature is different, so that the size of the air pool in the inner pipe 35 is different. It will be. In addition to this, since the air concentration in the air pool relatively increases due to a decrease in vapor pressure, even if the amount of air leak allowed in the sterilization standard (JIS standard), if the sterilization temperature is low, the heat exchanger Heat exchange with water flow in 30 is hindered, which may lead to a determination failure.

Therefore, the problem to be solved by the present invention is to provide an air leak detection device capable of detecting an air leak occurring during operation and capable of dealing with a change in sterilization temperature, and a steam sterilization device equipped with the same. .

The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 sterilizes an object to be sterilized in the sterilization tank by supplying steam into the sterilization tank after removing air from the sterilization tank. A heat exchanger having a hollow portion provided outside the sterilization tank, communicating with the inside of the sterilization tank, and having a liquid passing portion for exchanging heat with the fluid in the hollow section, Determination means for determining the presence or amount of air leakage into the sterilization tank based on the inlet temperature, outlet temperature and flow rate of the liquid with respect to the liquid passing part, and the hollow part is connected to the sterilization tank at one end. On the other hand, the air leak detection device is characterized in that the other end portion is provided with a protruding portion outward from the liquid passing portion.

According to the first aspect of the present invention, in the heat exchanger of the air leak detection device, the hollow portion communicates with the inside of the sterilization tank, and the liquid is passed through the liquid passage portion. Therefore, in the heat exchanger, the liquid in the liquid passing portion is heated and heated by the condensation heat transfer of the vapor from the inside of the sterilization tank. At this time, if there is an air leak in the sterilization tank, air is also introduced into the hollow part of the heat exchanger along with the steam. The amount of transmission is reduced, and the temperature rise of the liquid in the liquid passing portion is hindered. By utilizing this, it is possible to determine the presence or absence or the amount of air leak into the sterilization tank based on the inlet temperature, outlet temperature and flow rate of the liquid with respect to the liquid passing portion. In addition, the presence or amount of air leak can be determined during operation of the steam sterilizer, that is, during steam sterilization.

Also, the hollow part of the heat exchanger is provided with a protruding part outward from the liquid passing part on the side opposite to the connection side to the sterilization tank. Therefore, if there is an air leak into the sterilization tank, the air that remains without being condensed by heat exchange with the liquid in the liquid passage part is a mixture that flows continuously from the sterilization tank (vapor containing a small amount of air). ) Is pushed out to the protruding portion, so that the air concentration is hardly increased in the heat exchange portion of the heat exchanger. In this way, in the heat exchanger, the air that does not condense is moved to the protruding portion, whereby the heat exchange between the air-fuel mixture from the sterilization tank and the liquid in the liquid passing portion is not hindered by the residual air. In particular, even when the sterilization temperature (in other words, the vapor pressure) is low and the air compression is relatively low, adverse effects due to residual air can be prevented. Thereby, in a heat exchanger, the exact temperature change can be monitored irrespective of sterilization temperature, and the presence or absence and amount of air leak can be judged.

Furthermore, since the air leak detection device is provided outside the sterilization tank, there is no possibility of narrowing the space for storing the object to be sterilized in the sterilization tank, and there is no possibility of disturbing the removal and entry of the object to be sterilized. In addition, since the air leak detection device is provided outside the sterilization tank, there is no risk of receiving heat from the outside due to sterilization vapor, and the presence or amount of air leak can be accurately known.

According to a second aspect of the present invention, the heat exchanger includes an inner tube and an outer tube provided so as to surround the inner tube, and one end portion of the inner tube extends outward from the outer tube. By connecting to the sterilization tank, the hollow hole of the inner tube communicates with the inside of the sterilization tank, while the other end portion extends outward from the outer tube as the protruding portion, and the extended tip Water as the liquid is passed through the liquid passing portion formed by a cylindrical space between the inner tube and the outer tube, and a water supply / drain port for the cylindrical space is provided in the outer space. The air leak detection device according to claim 1, wherein the air leak detection device is provided on a peripheral side wall of the tube so as to be separated in a longitudinal direction of the outer tube.

According to the invention described in claim 2, the heat exchanger can be easily configured by using the double pipe of the inner pipe and the outer pipe. And while connecting one end of the inner tube to the sterilization tank, the other end of the inner tube extends outward from the outer tube, and can be used as a protrusion for collecting the remaining air without condensing. it can. Further, the cylindrical space between the inner tube and the outer tube becomes a liquid passing portion, and the liquid is taken in and out from the mouth portion separated in the longitudinal direction of the outer tube. And by using water as a liquid which lets a liquid flow part pass, while being able to procure easily and stably, it is safe also to the failure | damage of a heat exchanger by any chance.

According to a third aspect of the present invention, the outer pipe is provided with an extension pipe part that covers the projection part of the inner pipe, and a gap between the projection part of the inner pipe and the extension pipe part of the outer pipe is The air leak detection device according to claim 2, wherein the air leak detection device communicates with the cylindrical space as the liquid passing portion.

According to the third aspect of the present invention, the extension pipe part that covers the projection part of the inner pipe is provided in the outer pipe, and the gap between the projection part of the inner pipe and the extension pipe part of the outer pipe is communicated with the liquid passing part. It was. Thereby, the thermal expansion of the protrusion part of an inner tube can be suppressed.

According to a fourth aspect of the present invention, the inner pipe and the outer pipe are arranged with their axes extending in the vertical direction, and a lower mouth portion of the mouth portion for water supply / drainage provided in the outer tube is the cylinder. A water supply port to the cylindrical space, while an upper port portion is a drain port from the cylindrical space, and water is passed through the cylindrical space from below to above. The air leak detection device according to claim 2 or claim 3.

According to the invention described in claim 4, since the lower end of the inner pipe is connected to the sterilization tank, the introduction of steam into the inner pipe and the discharge of condensed water from the inner pipe are smoothly performed. Further, since water is passed through the cylindrical space between the inner tube and the outer tube from the bottom to the top, the air can be vented from the cylindrical space, and the presence or amount of air leak can be accurately determined. Can be determined.

According to a fifth aspect of the present invention, the liquid is passed through the liquid passing part at a set flow rate, and the determination means is configured to enter the sterilization tank based on the inlet temperature and the outlet temperature of the liquid with respect to the liquid passing part. The air leak detection device according to any one of claims 1 to 4, wherein presence or absence or amount of air leak is determined.

According to the fifth aspect of the present invention, the presence or amount of air leak into the sterilization tank is determined based on the inlet temperature and outlet temperature of the liquid with respect to the liquid passing part by passing the liquid through the liquid passing part at a set flow rate. can do.

According to a sixth aspect of the present invention, during the sterilization of an object to be sterilized in the sterilization tank, the determination means enters the sterilization tank based on the temperature difference between the liquid outlet temperature and the inlet temperature with respect to the liquid passing part. 6. The air leak detection device according to claim 5, wherein the presence or amount of air leak is determined.

According to the sixth aspect of the present invention, while the liquid to be sterilized is sterilized in the sterilization tank while passing the liquid through the liquid passing part at a set flow rate, the temperature difference between the liquid outlet temperature and the inlet temperature with respect to the liquid passing part is increased. Based on this, it is possible to easily and reliably determine the presence or amount of air leakage into the sterilization tank.

A seventh aspect of the present invention is a steam sterilization apparatus including the air leak detection device according to any one of the first to sixth aspects, wherein an object to be sterilized is accommodated and the air leak detection device is connected. A sterilization tank, a decompression means for depressurizing the inside of the sterilization tank by sucking and discharging the gas in the sterilization tank, and a decompression unit for introducing outside air into the sterilized tank that has been decompressed and restoring the pressure in the sterilization tank. Pressure supply means, steam supply means for supplying steam into the sterilization tank, drain discharge means for discharging condensed water of steam from the sterilization tank, and gas in the sterilization tank by the pressure difference from the atmospheric pressure. An exhaust means for discharging to the sterilization tank, a pressure sensor for detecting the pressure in the sterilization tank, a temperature sensor for detecting the temperature in the sterilization tank, and controlling each means based on detection signals from these sensors, A pretreatment step for eliminating air in the tank, Control means for sequentially executing a sterilization process for sterilizing an object to be sterilized in a tank with steam, an exhaust process for discharging steam from the sterilization tank, and a drying process for drying the object to be sterilized by reducing the pressure in the sterilization tank In the sterilization step, the steam sterilizer is characterized in that in the sterilization step, liquid is passed through the heat exchanger of the air leak detection device, and the determination means determines the presence or absence or amount of air leak into the sterilization tank. .

According to the invention described in claim 7, it is possible to realize a steam sterilization apparatus that exhibits the effects of the invention described in the above claims. In particular, in the sterilization process, the presence or amount of air leak into the sterilization tank can be determined by passing a liquid through the heat exchanger of the air leak detection device.

Furthermore, in the invention according to claim 8, in addition to the inlet temperature, the outlet temperature and the flow rate of the liquid with respect to the liquid passing part, the outlet temperature, in the case where the inlet temperature is not maintained at the set temperature, In the case where the flow rate is not maintained at the set flow rate, the flow rate is also stored in the operation data storage means every predetermined time during the sterilization process, and the data stored in the operation data storage means can be output to a predetermined device. The steam sterilization apparatus according to claim 7.

According to the invention described in claim 8, in addition to the liquid outlet temperature with respect to the liquid passing part, the inlet temperature and the flow rate are optionally stored in the operation data storage means every predetermined time during the sterilization process. Accordingly, since it can be output to a predetermined device, sterilization management can be performed easily and reliably.

According to the air leak detection apparatus of the present invention and the steam sterilization apparatus equipped with the same, it is possible to detect air leaks that occur during operation and to cope with changes in the sterilization temperature.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the air leak detection apparatus of one Example of this invention, and the steam sterilization apparatus provided with the same, and has shown one part in cross section. It is the schematic which shows the principal part of the air leak detection apparatus of FIG. 1, (A) is the case where sterilization temperature is 121 degreeC, (B) is the case where sterilization temperature is 135 degreeC, An air pocket is shown. It is a graph which shows an example of the experimental result which confirmed the influence of an air leak at the sterilization temperature of 121 degreeC, and when (A) and (B) are the air leak detection apparatuses of FIG. 2, (A ') and (B') are The case of the air leak detection apparatus of FIG. 6 is shown. It is a graph which shows an example of the experimental result which confirmed the influence of an air leak at the sterilization temperature of 135 degreeC, and when (A) and (B) are the air leak detection apparatuses of FIG. 2, (A ') and (B') are The case of the air leak detection apparatus of FIG. 6 is shown. It is the schematic which shows the modification of the air leak detection apparatus of FIG. It is the schematic which shows the principal part of the air leak detection apparatus of prior application invention, (A) is the case where sterilization temperature is 121 degreeC, (B) is the case where sterilization temperature is 135 degreeC, Indicates an air pocket.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an air leak detection apparatus 1 and a steam sterilization apparatus 2 having the same according to an embodiment of the present invention, and a part thereof is shown in cross section. In FIG. 1, the air leak detection device 1 is shown in an enlarged manner as compared with the steam sterilization device 2. Hereinafter, the steam sterilization apparatus 2 will be described first, and then the air leak detection apparatus 1 will be described.

The steam sterilization apparatus 2 according to the present embodiment includes a sterilization tank 3 in which an object to be sterilized is stored and an air leak detection apparatus 1 is connected, and a gas in the sterilization tank 3 is sucked and discharged to the outside. Depressurization means 4 for depressurization, return pressure means 5 for introducing outside air into the depressurized sterilization tank 3 to restore the pressure in the sterilization tank 3, steam supply means 6 for supplying steam into the sterilization tank 3, and sterilization tank A drain discharge means 7 for discharging steam condensate from the inside 3, an exhaust means 8 for discharging the gas in the sterilization tank 3 to the outside by a differential pressure from the atmospheric pressure, and a first for controlling these means 4 to 8 Control means (not shown).

The material 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 3 or placed on a cart and the entire cart is accommodated in the sterilization tank 3.

The sterilization tank 3 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 3 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 3 and the other door is sterilized after sterilization outside the sterilization tank 3. It is good also as a carrying-out door for taking out an object. In any case, the opening of the sterilization tank 3 can be hermetically closed by closing the door. That is, the gap between the sterilization tank 3 and the door is sealed with packing (not shown). At this time, the annular packing provided along the opening of the sterilization tank 3 may be pressed against the door with pressurized air to seal the gap between them.

In order to warm the inside of the sterilization tank 3 from the outside, a steam jacket 9 is provided on the outer wall of the sterilization tank 3 in this embodiment. Specifically, the steam sterilization apparatus 2 includes an inner can 10 and an outer can 11, and the inner can 10 constitutes the sterilization tank 3, and a gap between the inner can 10 and the outer can 11 serves as a steam jacket 9. The In the present embodiment, the steam jacket 9 is continuously provided on each of the upper, lower, left and right walls of the sterilization tank 3. Steam is supplied to the steam jacket 9 via a jacket steam supply path (not shown), and 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 9 so as to maintain the inside of the steam jacket 9 at a predetermined pressure, the inside of the sterilization tank 3 can be heated from the outside at a predetermined temperature.

The decompression means 4 sucks and discharges the gas in the sterilization tank 3 to the outside through the vacuum exhaust path 12. A vacuum valve 13, a water-sealed vacuum pump 14, and a check valve 15 are sequentially provided in the vacuum exhaust path 12 from the sterilization tank 3. Further, the vacuum exhaust path 12 may be provided with a heat exchanger for vapor condensation between the vacuum valve 13 and the vacuum pump 14. By opening the vacuum valve 13 and operating the vacuum pump 14, the gas in the sterilization tank 3 can be sucked and discharged outside, and the inside of the sterilization tank 3 can be decompressed.

The decompression means 5 introduces outside air into the sterilization tank 3 under reduced pressure via the air supply path 16. In the air supply path 16 into the sterilization tank 3, an air filter 17, an air supply valve 18, and a check valve 19 are provided in this order. However, the installation order of the air supply valve 18 and the check valve 19 may be switched. When the air supply valve 18 is opened while the inside of the sterilization tank 3 is decompressed, the outside air can be introduced into the sterilization tank 3 by the differential pressure, and the inside of the sterilization tank 3 can be restored. At that time, clean air is introduced into the sterilization tank 3 by the air filter 17. If the air supply valve 18 is configured so that the opening degree can be adjusted, the return pressure in the sterilization tank 3 can be gradually increased.

The steam supply means 6 supplies steam (saturated steam) into the sterilization tank 3 through the steam supply path 20. A steam supply valve 21 is provided in the steam supply path 20. By opening the steam supply valve 21, steam from a steam supply source (not shown) can be supplied into the sterilization tank 3. The presence / absence or amount of steam supply into the sterilization tank 3 can be changed by adjusting the opening / closing or opening of the steam supply valve 21.

The drain discharge means 7 discharges steam condensate from the sterilization tank 3 through the drain discharge path 22. A steam trap 23 and a check valve 24 are sequentially provided in the drain discharge path 22 from the sterilization tank 3. While steam is being supplied into the sterilization tank 3 by the steam supply means 6, the condensed water of the steam is discharged out of the sterilization tank 3 by the drain discharge means 7.

The exhaust means 8 leads the gas out of the sterilization tank 3 under pressure through the exhaust path 25. An exhaust valve 26 and a check valve 27 are sequentially provided in the exhaust path 25 from the inside of the sterilization tank 3. When the exhaust valve 26 is opened while the inside of the sterilization tank 3 is pressurized, the gas in the sterilization tank 3 can be led out to the outside by the differential pressure, and the pressure in the sterilization tank 3 can be lowered. In the illustrated example, the exhaust passage 25 is a common conduit with the drain discharge passage 22 on the upstream side (sterilization tank 3 side).

The sterilization tank 3 is provided with a pressure sensor 28 for detecting the pressure in the sterilization tank 3 and a temperature sensor 29 for detecting the temperature in the sterilization tank 3. The installation position of the pressure sensor 28 is not particularly limited. For example, as shown in the drawing, the pressure sensor 28 is provided on the upper side of the sterilization tank 3. On the other hand, the temperature sensor 29 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 3 among the said common pipe lines (common pipe line of the drain discharge path 22 and the exhaust path 25).

The first control means is a first controller (not shown) for controlling the means 4 to 8 based on the detection signals and elapsed time of the sensors 28 and 29. Specifically, the vacuum valve 13, the vacuum pump 14, the air supply valve 18, the steam supply valve 21, the exhaust valve 26, the pressure sensor 28, the temperature sensor 29, and the like are connected to the first controller. And a 1st controller aims at the sterilization of the to-be-sterilized thing in the sterilization tank 3 according to a predetermined procedure (program) so that it may mention later.

Furthermore, in this embodiment, the steam sterilizer 2 includes operation buttons (not shown) and the like as desired in addition to a touch panel (not shown), which are also connected to the first controller. The touch panel is configured by arranging an input panel on the surface of the display, and various displays are made on the display, and when the display button on the display is pressed, the input panel detects it and various screen displays are appropriately changed. Allows setting or operation. Data on the display screen of the touch panel, an operation program for the steam sterilizer 2, and the like are stored in an information storage unit (not shown). This information storage unit can also be used as an operation data storage unit (operation data storage means) for storing operation data described later.

The operation content of the steam sterilizer 2 is not particularly limited, but typically, a preheating process, a pretreatment process, a sterilization process, an exhaust process, and a drying process are sequentially performed. Hereinafter, each step will be described. In the initial state, the air supply valve 18 and the exhaust valve 26 are open, while the other valves 13 and 21 are closed, and the vacuum pump 14 is stopped. During or before or after the preheating step, an object to be sterilized is accommodated in the sterilization tank 3, and the door of the sterilization tank 3 is closed in an airtight manner. At that time, the air supply valve 18 and the exhaust valve 26 are also closed.

In the preheating process, the inside of the sterilization tank 3 is heated. Specifically, steam is supplied into the steam jacket 9, and the inside of the steam jacket 9 is maintained at a predetermined pressure, whereby the inside of the sterilization tank 3 is heated and maintained at a predetermined temperature. The pretreatment process is started after a predetermined time has elapsed 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, the air in the sterilization tank 3 is removed. Specifically, the inside of the sterilization tank 3 is decompressed by the decompression means 4, but at that time, steaming by the steaming means 6 may be accompanied. Further, after the inside of the sterilization tank 3 is once decompressed by the decompression means 4, the steaming by the steaming means 6 and the decompression by the decompression means 4 may be repeated, or until the pressure exceeds the atmospheric pressure by the steaming by the steaming means 6. When pressurizing the inside of the sterilization tank 3, the steaming by the steaming means 6 and the exhausting by the exhaust means 8 may be repeated. In any case, after exhausting air from the inside of the sterilization tank 3, finally, the inside of the sterilization tank 3 is increased to the sterilization pressure by steaming by the steaming means 6. When the temperature detected by the temperature sensor 29 reaches the sterilization temperature or the pressure detected by the pressure sensor 28 reaches the sterilization pressure, the process proceeds to the next step.

In the sterilization process, the object to be sterilized in the sterilization tank 3 is sterilized with steam. Specifically, the steam supply means 6 is controlled so that the temperature detected by the temperature sensor 29 maintains the sterilization temperature (typically 121 ° C. or 135 ° C.), and the sterilization tank 3 is maintained. Sterilize the items to be sterilized. Alternatively, the steam supply means 6 is controlled so that the pressure detected by the pressure sensor 28 maintains the sterilization pressure (saturated steam pressure corresponding to the sterilization temperature), and the sterilization time is maintained. Sterilize. Thereafter, the steaming by the steaming means 6 is stopped and the process proceeds to the next step.

In the exhaust process, steam is discharged from the sterilization tank 3 under pressure, and the pressure in the sterilization tank 3 is reduced to near atmospheric pressure. Specifically, the exhaust valve 26 is opened and the steam is led out of the sterilization tank 3. When the set exhaust time elapses from the opening of the exhaust valve 26 or when the pressure in the sterilization tank 3 drops to the set exhaust pressure (atmospheric pressure or a slightly higher pressure), the exhaust valve 26 is closed and the process proceeds to the next step. To do.

In the drying process, the object to be sterilized in the sterilization tank 3 is dried. Specifically, the inside of the sterilization tank 3 is vacuum-dried by reducing the pressure inside the sterilization tank 3 to the drying pressure by the decompression means 4 and holding the drying time. However, in the drying process, the decompression to the drying pressure by the decompression means 4 and the decompression to near atmospheric pressure by the decompression means 5 may be repeated. After the object to be sterilized is dried, the decompression means 4 is stopped, while the decompression means 5 restores the pressure in the sterilization tank 3 to atmospheric pressure, and the series of operations is completed.

Next, the air leak detection device 1 of this embodiment will be described. The air leak detection apparatus 1 of the present embodiment includes a heat exchanger 30 connected to the sterilization tank 3, a water supply / drainage means 31 for the heat exchanger 30, and controls the water supply / drainage means 31, and air leaks into the sterilization tank 3. Second control means (not shown) for determining presence or absence or amount.

The heat exchanger 30 is provided outside the sterilization tank 3 and has a hollow part 32 communicating with the inside of the sterilization tank 3 and a liquid passage part 33 for exchanging heat with the fluid in the hollow part 32. That is, the heat exchanger 30 exchanges heat without mixing the fluid in the hollow portion 32 and the liquid flow in the liquid flow portion 33. The liquid passed through the liquid passing portion 33 is not particularly limited, but is typically water (normal temperature water). Hereinafter, the liquid that is passed through the liquid passing portion 33 will be described as water, but the same applies to other liquids.

The heat exchanger 30 has the hollow portion 32 and the liquid passing portion 33 described above, and the sterilization tank 3 is connected to one end portion of the hollow portion 32, while the other end portion of the hollow portion 32 is outwardly described later. If the protrusion part 34 of this is provided, the structure in particular will not be ask | required. The heat exchanger 30 of the present embodiment is composed of a metal double tube. Specifically, in FIG. 1, the heat exchanger 30 includes an inner tube 35 that is disposed along an axis in the vertical direction, and an outer tube 36 that is provided so as to surround the inner tube 35.

The inner tube 35 and the outer tube 36 are preferably circular in cross section and are arranged with their axes aligned. Moreover, each pipe part of the inner pipe 35 and the outer pipe 36 may be configured by connecting a plurality of members as desired. However, it is preferable that the inner tube 35 is formed of a single tube at least above the lower end portion of the outer tube 36 in consideration of thermal stress.

The outer tube 36 has a basic portion (main body portion) in a region indicated by a symbol L in FIG. Therefore, in the following, when simply referred to as the outer tube 36, it usually refers to the main body of the outer tube 36. On the other hand, the inner tube 35 extends downward from the lower end portion of the outer tube 36 and extends upward from the upper end portion of the outer tube 36. That is, although details will be described later as a modified example, the basic configuration of the heat exchanger 30 of the present embodiment is such that the inner tube 35 extends through the outer tube 36 to both sides in the axial direction, as shown in FIG. It is supposed to be configured.

In FIG. 1, the lower end portion of the inner tube 35 is connected to the sterilization tank 3 through a communication tube 37. Thereby, the hollow hole of the inner tube 35 communicates with the inside of the sterilization tank 3. On the other hand, the upper end portion of the inner tube 35 extends upward from the outer tube 36, and the upper opening of the extended portion is closed by the upper end wall 38. In the inner tube 35, a portion extending upward from the outer tube 36 is simply referred to as a protruding portion 34.

The protrusion 34 of the inner pipe 35 is set in size so as to function as an air reservoir in the sterilization process, as will be described in detail later. Preferably, the sterilization temperature is minimum (that is, the vapor pressure is minimum), and at least the maximum air leak level allowed by the sterilization standard (Note that the air leak level is a pressure increase due to air in the sterilization tank 3 within a predetermined time. (KPa / min)) air is mixed into the steam, the air mixture remains in the sterilization process through heat exchange with the water flow in the heat exchanger 30, but the residual air remains in the sterilization process. It is set to a size that can be stored in In the present embodiment, for example, the length of the outer tube 36 is about 1/2 to 1 times, and in the illustrated example, it is about 3/4 times.

At the upper end portion of the outer tube 36, an extension tube portion 39 that covers the protruding portion 34 of the inner tube 35 is provided. At this time, the extension tube portion 39 may be formed integrally with the outer tube 36, or a tube separate from the outer tube 36 may be connected to the outer tube 36.

At the lower end of the outer tube 36, the lower opening of the outer tube 36 (in other words, the gap between the outer tube 36 and the inner tube 35) is closed by the lower end wall 40. On the other hand, at the upper end portion of the extension pipe portion 39 of the outer pipe 36, the upper opening of the extension pipe portion 39 is closed by the upper end wall 41. At this time, the upper end wall 38 of the inner tube 35 and the upper end wall 41 of the outer tube 36 may be shared, and the upper ends of the inner tube 35 and the outer tube 36 may be connected to one upper end wall, which will be described later. Thus, in order to alleviate thermal stress due to thermal expansion and contraction of the inner tube 35, the inner tube 35 and the outer tube 36 are closed by different upper end walls 38 and 41 as shown in the figure, and a gap is formed between them. It is good to leave a gap.

The cylindrical space between the outer peripheral surface of the inner tube 35 and the inner peripheral surface of the outer tube 36 is a jacket-like liquid passing portion 33. For this purpose, on the peripheral side wall of the outer tube 36, water supply / drain ports 36 a and 36 b for the liquid passage portion 33 are provided in the longitudinal direction of the outer tube 36. Specifically, cylindrical mouth portions 36 a and 36 b are provided at both upper and lower ends of the peripheral side wall of the outer tube 36 so as to extend outward in the radial direction of the outer tube 36. The mouth parts 36 a and 36 b are water inlets and outlets for the liquid passage part 33 and are connected to the water supply / drainage means 31.

Further, in the protruding portion 34 of the inner tube 35 and the extended tube portion 39 of the outer tube 36, the space between the outer peripheral surface of the protruding portion 34 and the inner peripheral surface of the extended tube portion 39 (and the upper end wall 38 of the inner tube 35 and the outer tube). A gap is formed between the upper end wall 41 of 36 and the gap communicates with the liquid passing portion 33. In the illustrated example, a cylindrical space between the inner tube 35 and the outer tube 36 is also continuously formed between the projecting portion 34 and the extension tube portion 39 so as to communicate with each other.

In this way, if the water passing through the liquid passing portion 33 flows also into the gap between the projecting portion 34 and the extension pipe portion 39, the thermal expansion of the inner pipe 35 portion can be suppressed. Further, since the inner tube 35 is welded and held to the lower end wall 40 at the lower end portion of the outer tube 36 and the upper end portion is a free end, also from this point, due to thermal expansion and contraction of the inner tube 35. Thermal stress can be reduced.

By the way, the liquid passing portion 33 basically means a region where the liquid is circulated in one way. The gap between the protruding portion 34 of the inner tube 35 and the extended tube portion 39 of the outer tube 36 can be distinguished from the liquid passing portion 33 because the liquid does not flow easily. The boundary between the two (the upper end position of the liquid passing portion 33) depends on the arrangement of the mouth portions 36a and 36b, but at least the portion corresponding to the uppermost portion of the inner peripheral surface of the upper mouth portion 36b is the liquid passing portion. 33. In the present embodiment, the region indicated by the symbol L in FIG.

The lower end of the inner pipe 35 is connected to the sterilization tank 3 via a communication pipe 37 in the illustrated example. The communication pipe 37 is composed of, for example, a pipe having the same inner and outer diameter as the inner pipe 35. In that case, the communication pipe 37 and the inner pipe 35 can be configured continuously, in other words, as one member. However, the inner and outer diameters of the communication pipe 37 may be different from the inner and outer diameters of the inner pipe 35. The heat exchanger 30 and the communication pipe 37 are preferably covered with a heat insulating material. In the illustrated example, the heat exchanger 30 is provided with a flange 42 for attachment to the wall.

The water supply / drainage means 31 passes water through the liquid passage portion 33 of the heat exchanger 30. As described above, in the present embodiment, the liquid passing portion 33 of the heat exchanger 30 is configured by a cylindrical space between the inner tube 35 and the outer tube 36. It is preferable that the water is passed through. Therefore, in the present embodiment, the lower mouth portion 36a is a water supply port, and the upper mouth portion 36b is a drain port.

The water supply / drainage means 31 will be described in detail. A water supply passage 43 and a drainage passage 44 are connected to the liquid passing portion 33. In the present embodiment, as described above, cylindrical mouth portions 36 a and 36 b are provided at both upper and lower end portions of the peripheral side wall of the outer tube 36 so as to extend outward in the radial direction of the outer tube 36. The water supply channel 43 is connected to the lower port 36a, while the drainage channel 44 is connected to the upper port 36b. At this time, in the illustrated example, T-shaped tubes 45 (45X, 45Y) are used for the respective connecting portions. The T-shaped tube 45 is integrally formed with a straight tubular (short tubular) main tube portion 45a extending in the left-right direction and a branch tube portion 45b extending radially outward from the longitudinal central portion of the main tube portion 45a. ing.

And the lower mouth part 36a and the water supply channel 43 are connected as follows. That is, the lower T-shaped tube 45X is disposed along the main pipe portion 45a in the left-right direction, one opening is connected to the lower mouth 36a, and the other opening has an inlet temperature sensor described later. 46 is closed while being provided. And the branch pipe part 45b is arrange | positioned toward the downward direction, and the water supply path 43 is connected to the lower opening.

On the other hand, the upper mouth part 36b and the drainage channel 44 are connected as follows. That is, the upper T-shaped tube 45Y is disposed along the main pipe portion 45a in the left-right direction, one opening is connected to the upper mouth 36b, and an outlet temperature sensor 47 described later is provided in the other opening. It is closed while being provided. And it arrange | positions with the branch pipe part 45b facing upwards, and the drainage channel 44 is connected to the upper opening.

With such a configuration, water is passed through the liquid passing portion 33 of the heat exchanger 30 from below to above. Therefore, air can be naturally removed from the liquid passing portion 33 of the heat exchanger 30, and heat exchange between the water passing through the liquid passing portion 33 and the fluid in the hollow portion 32 can be stably achieved.

In the water supply path 43, a strainer 48, a water supply valve 49, a pressure reducing valve 50, and a flow rate adjusting nozzle 51 are sequentially provided toward the heat exchanger 30. The strainer 48 captures contaminants in the water, the water supply valve 49 is composed of an electromagnetic valve, and the pressure reducing valve 50 maintains the outlet side pressure at a predetermined level. The flow rate adjusting nozzle 51 allows water to flow through the heat exchanger 30 at a set flow rate when the water supply valve 49 is opened.

By the way, in the present embodiment, the water supply valve 49 is opened so that water can be passed through the heat exchanger 30 by the pressure of the water supply source. However, depending on the pressure of the water supply source, a water supply pump may be installed in the water supply path 43 instead of or in addition to the water supply valve 49. In that case, in the following description, when the water supply valve 49 is opened, the water supply pump may be operated. When the water supply pump is constituted by a constant flow pump, the installation of the pressure reducing valve 50 and the flow rate adjusting nozzle 51 can be omitted.

The drainage channel 44 is connected to the branch pipe portion 45b of the upper T-shaped tube 45Y as described above. In that case, it connects to the upper part of the branch pipe part 45b toward the upper direction, and in the example shown in the figure, it is finally piped to a lower drainage pit or the like via an appropriate pipe such as an elbow pipe. The drainage channel 44 may be provided with a drainage valve if desired. In that case, the drain valve is controlled to open and close in conjunction with the water supply valve 49.

Temperature sensors 46 and 47 are provided so that the inlet temperature and outlet temperature of water with respect to the liquid passing portion 33 can be monitored. Specifically, an inlet temperature sensor 46 is provided at the inlet portion to the liquid passage portion 33, and an outlet temperature sensor 47 is provided at the outlet portion from the liquid passage portion 33. In the illustrated example, as described above, in the main pipe portion 45a of the lower T-shaped tube 45X, one opening is connected to the mouth 36a of the heat exchanger 30, and the inlet temperature sensor 46 is inserted into the other opening. Provided. The main tube portion 45a of the upper T-shaped tube 45Y has one opening connected to the mouth 36b of the heat exchanger 30, and the outlet temperature sensor 47 inserted into the other opening. In addition, the water supply channel 43 or the drainage channel 44 may be provided with a flow rate sensor (not shown) for monitoring the water flow rate, if desired. In particular, a flow rate sensor is provided when water cannot be passed at a set flow rate due to the absence of the flow rate adjusting nozzle 51 or the like.

The second control means is a second controller (not shown) that controls the water supply / drainage means 31 and the like based on the detection signals of the sensors 46 and 47, the elapsed time, and the like. Specifically, the inlet temperature sensor 46 and the outlet temperature sensor 47 as well as the water supply valve 49 are connected to the second controller. The second controller also functions as a determination unit that determines the presence or absence or amount of air leak into the sterilization tank 3 as described below.

As with the first controller, a touch panel (not shown), operation buttons (not shown), and an information storage unit (not shown) are connected to the second controller as desired. The information storage unit also functions as an operation data storage unit (operation data storage means) for storing operation data described later.

The second controller is also connected to the first controller so that the process being performed by the steam sterilizer 2 can be grasped. However, instead of this, the second controller may be shared with the first controller. That is, the first controller for controlling the operation of the steam sterilizer 2 may have a determination function for determining the presence or amount of air leakage into the sterilization tank 3. Hereinafter, although an example in which the first controller and the second controller are configured as one common controller will be described, the first controller and the second controller may be configured separately. In that case, the first controller controls the operation of the steam sterilizer 2 as described above, and the second controller executes each process described below. When the first controller and the second controller are configured separately, it is easy to retrofit the existing or existing steam sterilizer 2 with the air leak detector 1 of the present embodiment.

Hereinafter, the usage method of the air leak detection apparatus 1 of a present Example is demonstrated.
As described above, in the steam sterilization apparatus 2, the preheating process, the pretreatment process, the sterilization process, the exhaust process, and the drying process are sequentially performed. In the pretreatment process, air is excluded from the inside of the sterilization tank 3, and accordingly, air is also excluded from the inner pipe 35 of the heat exchanger 30 communicating with the inside of the sterilization tank 3 (in other words, inside the hollow portion 32). Is made. In the subsequent sterilization process, steam is introduced into the sterilization tank 3, and accordingly, steam is also introduced into the inner pipe 35 of the heat exchanger 30.

Among the above steps, at least during the sterilization step, water is supplied to the liquid passing portion 33 of the heat exchanger 30 by the water supply / drainage means 31. For example, with the start of the sterilization process, the water supply valve 49 is opened and water is passed through the liquid passage portion 33 of the heat exchanger 30. Thereby, the fluid in the hollow part 32 and the water flow of the liquid passing part 33 are heat-exchanged, and the outlet side water temperature of the liquid passing part 33 becomes higher than the inlet side water temperature. That is, in the heat exchanger 30, the water passing through the liquid passing portion 33 is heated and heated by the condensation heat transfer of the steam from the sterilization tank 3. Here, if an air leak into the sterilization tank 3 occurs (for example, when the pressure in the sterilization tank 3 is reduced in the pretreatment step, air flows into the sterilization tank 3 from the outside, or between the sterilization tank 3 and the door. When pressurized air for pressurizing the packing that seals the gap flows into the sterilization tank 3), air is also introduced into the hollow portion 32 of the heat exchanger 30 along with the steam, and the air is introduced into the steam. The amount of heat transfer to the water passing through the liquid passing portion 33 is reduced by the amount of the mixed water, and the temperature rise of the water passing through the liquid passing portion 33 is hindered. Utilizing this, the presence or absence of air leak into the sterilization tank 3 (more specifically, the presence or absence of air leak exceeding the reference value) or the amount (air Can also be said to be the ratio or concentration occupied by.

In this way, during the sterilization process (however, it may be during the sterilization process after the set time has elapsed since the start of the sterilization process, etc.), based on the water inlet temperature, outlet temperature and flow rate with respect to the liquid passing part 33, The presence or amount of air leak can be determined. Specifically, the controller can grasp the amount of heat by which the water flow is heated in the heat exchanger 30 based on the detection signals of the inlet temperature sensor 46, the outlet temperature sensor 47, and the flow rate sensor. Whether or not there is an air leak into the sterilization tank 3 can be determined by whether or not it is less. Further, as the amount of air leak increases, the amount of heat that is passed through the heat exchanger 30 decreases, and the amount of air leak and the amount of water that passes through the heat exchanger 30 have a certain relationship. The amount of air leak can be determined based on the amount of heat by which the water flow in the heat exchanger 30 is heated.

Here, as shown in the illustrated example, when water is passed through the liquid passing portion 33 at a set flow rate, the presence or amount of air leak into the sterilization tank 3 is determined based on the water inlet temperature and outlet temperature with respect to the liquid passing portion 33. You can also That is, when the water flow rate to the liquid flow part 33 can be maintained at the set flow rate, the controller determines whether or not air leaks into the sterilization tank 3 based on the detection signals of the inlet temperature sensor 46 and the outlet temperature sensor 47. Can be determined. At this time, the presence or absence of air leak into the sterilization tank 3 can also be determined based on whether or not the temperature difference between the water outlet temperature and the inlet temperature with respect to the heat exchanger 30 during the sterilization process is less than a set value. That is, if the temperature difference is less than the set value, it can be determined that there is an air leak into the sterilization tank 3, and if the temperature difference is greater than the set value, it can be determined that there is no air leak into the sterilization tank 3. Also, the smaller the temperature difference, the greater the amount of air leak, so the amount of air leak can also be determined based on the temperature difference. Note that the presence / absence or amount of air leak may be determined based on the maximum temperature difference between the outlet temperature of the water flow and the inlet temperature during the sterilization process.

Further, when water is passed through the liquid passing part 33 at a set flow rate and the inlet water temperature of the liquid passing part 33 can be maintained at the set temperature, the air leak into the sterilization tank 3 is caused based on the water outlet temperature to the liquid passing part 33. Presence or absence or amount can also be determined. For example, when the water flow rate to the liquid flow part 33 can be maintained at the set flow rate and the water supply temperature to the liquid flow part 33 can be maintained at the set temperature, the controller for the controller is omitted by omitting the installation of the inlet temperature sensor 46. Based on the detection signal of the outlet temperature sensor 47, it is possible to determine the presence or absence or amount of air leak into the sterilization tank 3. At this time, whether or not there is an air leak into the sterilization tank 3 can also be determined depending on whether or not the outlet temperature of water with respect to the heat exchanger 30 is lower than a set value during the sterilization process. That is, if the outlet temperature is lower than the set value, it can be determined that there is an air leak into the sterilization tank 3, and if the outlet temperature is equal to or higher than the set value, it can be determined that there is no air leak into the sterilization tank 3. Further, it is possible to grasp the amount of air leak based on the outlet temperature.

In any case, unlike conventional leak tests, air leaks during sterilization operation can be detected. Then, preferably, until the end of the sterilization process, the presence or absence of air leak is continuously monitored, and the result is output to an output device (for example, a touch panel provided in the steam sterilizer 2 or the air leak detector 1) as desired. Can do. That is, when it is determined that there is an air leak into the sterilization tank 3, the fact is output to an output device (for example, a touch panel) to notify the abnormality. Alternatively, instead of or in addition to this, the operation of the steam sterilizer 2 may be stopped.

By the way, in the air leak detection device 1 of the present embodiment, the inner tube 35 includes the protruding portion 34 outward from the liquid passing portion 33, so that when there is an air leak into the sterilization tank 3, The air remaining without being condensed by heat exchange with the water flow is pushed out to the projecting portion 34 by the air-fuel mixture (steam containing a small amount of air) that continuously flows from the sterilization tank 3. Air concentration is unlikely to increase in the heat exchange section. As described above, in the heat exchanger 30, by moving the non-condensed air to the projecting portion 34, heat exchange between the air-fuel mixture from the sterilization tank 3 and the water passing through the liquid passing portion 33 is inhibited by the residual air. There is nothing to do. In particular, even when the sterilization temperature (in other words, the vapor pressure) is low and the air compression is relatively low, adverse effects due to residual air can be prevented. Thereby, in the heat exchanger 30, the exact temperature change can be monitored irrespective of sterilization temperature, and the presence or absence and quantity of an air leak can be determined.

2A and 2B are schematic views showing the main part of the air leak detection device 1 of the present embodiment. FIG. 2A shows a case where the sterilization temperature is 121 ° C. and FIG. 2B shows a case where the sterilization temperature is 135 ° C. A shaded portion at the top of the pipe 35 indicates an air reservoir (portion where the air concentration is high). On the other hand, FIG. 6 is a schematic view showing a main part of the air leak detection apparatus 1 having no protrusion 34 in the inner tube 35 as a comparative example. (A) is a sterilization temperature of 121 ° C., (B) is sterilization. This is a case where the temperature is 135 ° C., and the shaded portions at the upper part of the inner tube 35 indicate air pools. In these figures, the inner tube 35 and the protruding portion 34 actually have a mixture of steam and air, and the air concentration (also referred to as the air partial pressure) increases upward. Air accumulates to be higher. Therefore, it can be said that the shaded portion in the drawing is a portion where the air concentration is relatively high, which is shown as an air reservoir.

As is clear from the comparison between FIG. 2A and FIG. 6A and the comparison between FIG. 2B and FIG. 6B, the projection 34 is not provided in the inner tube 35 (FIG. 6) Since the air remaining without being condensed due to heat exchange with the water flow in the liquid passage portion 33 is accumulated in the inner pipe 35 having a height corresponding to the liquid flow portion 33, the heat exchange is continuously inhibited. However, when the projecting portion 34 is provided in the inner pipe 35 (FIG. 2), the air remaining without being condensed due to heat exchange with the water passing through the liquid passing portion 33 protrudes above the liquid passing portion 33. It is pushed out to the part 34 and does not hinder heat exchange with the gas from the sterilization tank 3.

In particular, when the sterilization temperature is low, the pressure in the inner pipe 35 is reduced, so that the air pool is increased, and the air concentration in the heat exchange part (in the inner pipe 35 at a height corresponding to the liquid passing part 33) is increased. Cheap. Therefore, as shown in FIG. 6A, if the protrusion 34 is not provided on the inner pipe 35, the influence of the residual air in the inner pipe 35 is large, and the amount of air leak allowed in the sterilization standard (JIS standard) However, heat exchange with water flow in the heat exchanger 30 is hindered, which may lead to a determination failure. On the other hand, as shown in FIG. 2A, if the protrusion 34 is provided in the inner pipe 35, the residual air is pushed out to the protrusion 34 by the vapor pressure from the inside of the sterilization tank 3. Then, an air-fuel mixture (a mixture of steam and air) from the inside of the sterilization tank 3 sequentially flows into the heat exchanging portion of the heat exchanger 30, and heat exchange is performed between the air-fuel mixture and the liquid in the liquid passing portion 33. The In the heat exchanger 30, the heat exchange between the air-fuel mixture from the sterilization tank 3 and the water passing through the liquid passing portion 33 is not hindered by the residual air by moving the non-condensed air to the protruding portion 34. . Thereby, in the heat exchanger 30, the exact temperature change can be monitored irrespective of sterilization temperature, and the presence or absence and quantity of an air leak can be determined.

FIG. 3 is a graph showing an example of an experimental result in which the effect of air leak was confirmed at a sterilization temperature of 121 ° C., and (A) and (B) show the air leak detection device 1 in which the protruding portion 34 is provided on the inner tube 35. In the case of FIG. 2, (A ′) and (B ′) show the case of the air leak detection device 1 (FIG. 6) in which the protrusion 34 is not provided on the inner pipe 35. FIG. 4 is a graph showing an example of an experimental result in which the influence of air leak was confirmed at a sterilization temperature of 135 ° C., and (A) and (B) show air leak detection in which a protruding portion 34 is provided on the inner tube 35. In the case of the device 1 (FIG. 2), (A ′) and (B ′) show the case of the air leak detection device 1 (FIG. 6) in which the protruding portion 34 is not provided on the inner tube 35.

In each figure, T is the temperature in the sterilization tank 3 (left vertical axis), P is the pressure in the sterilization tank 3 (right vertical axis), and ΔT is the detected temperature of the outlet temperature sensor 47 and the inlet temperature sensor 46. The temperature difference from the detected temperature (left vertical axis) is shown. In addition, the horizontal axis is the elapsed time, and it is shown that each step from the preheating step to the drying step is sequentially performed, and the sterilization tank temperature T is about 121 ° C. (FIG. 3) or about 135 ° C. The location where (FIG. 4) is maintained substantially horizontal corresponds to the sterilization process. Further, at the bottom of each graph, the degree of leak (kPa / min) and the maximum temperature difference ΔT during the sterilization process are shown.

In each figure, as can be seen from the comparison between (A) and (A ′) and the comparison between (B) and (B ′), the protruding portion 34 is provided on the inner tube 35 even with the same leak amount. By providing, ΔT can be increased. Therefore, even when the sterilization temperature, that is, the steam pressure is low, the presence or amount of air leak can be determined stably and reliably based on ΔT. That is, since the water temperature changes even when the sterilization temperature is relatively low, a temperature difference as a criterion for determining air leak can be secured in a general sterilization temperature region (121 to 135 ° C.). Thereby, an air leak amount (leak degree) smaller than the sterilization standard (JIS) is determined to be normal, while an air leak amount larger than the sterilization standard can be determined to be defective. In addition, although the maximum temperature difference ΔT during the sterilization process is indicated by a numerical value at the bottom of each graph, the presence or absence of air leak can be determined based on this numerical value.

In addition, according to the air leak detection apparatus 1 of this embodiment and the steam sterilization apparatus 2 provided with the same, the air leak detection apparatus 1 (particularly the heat exchanger 30) is provided outside the sterilization tank 3, so There is no risk of narrowing the space for storing the sterilized material, and there is no risk of disturbing the removal and entry of the sterilized material. In addition, since the air leak detection device 1 is provided outside the sterilization tank 3, there is no risk of receiving heat from the outside due to sterilization vapor, and the presence or absence of air leak into the sterilization tank 3 can be accurately known.

Incidentally, it is preferable that the controller (first controller or second controller) can perform sterilization management as follows. That is, among the inlet temperature, outlet temperature, and flow rate of water to the liquid passing part 33, in addition to the outlet temperature, the inlet temperature is not maintained at the set temperature, and the inlet temperature is also not maintained at the set flow rate. The flow rate is preferably stored in the operation data storage unit at predetermined intervals at least during the sterilization process, and the data stored in the operation data storage unit can be output to a predetermined device.

For example, when water can be passed at a set flow rate by the flow rate adjusting nozzle 51, the detected temperatures of the inlet temperature sensor 46 and the outlet temperature sensor 47 are stored in the operation data storage unit at predetermined time intervals (for example, at intervals of several seconds). At that time, in addition to various setting values such as operation date and time, sterilization conditions (sterilization pressure, sterilization temperature, sterilization time), the pressure and temperature in the sterilization tank 3 are stored every predetermined time during actual operation. It is preferable to do this. And these data are acquired from an operation data storage part, for example based on an operation date, as needed, and can be output to a touch panel etc. now. Thereby, the past history can be confirmed, and sterilization management can be performed easily and reliably.

Next, a modified example of the air leak detection device 1 of the present embodiment will be described. FIG. 5 is a schematic diagram showing a modification of the air leak detection device 1 of FIG.

The air leak detection device 1 of the present modification is basically the same as the air leak detection device 1 of the above embodiment. Therefore, the following description will focus on the differences between the two, and description of the same parts will be omitted. Corresponding portions will be described with the same reference numerals. In addition, in FIG. 5, although only the location of the heat exchanger 30 is shown, the structure of those other than this is the same as that of FIG.

In the above-described embodiment, the axes of the inner tube 35 and the outer tube 36 are arranged along the vertical direction, but in this modification, the axes of the inner tube 35 and the outer tube 36 are arranged along the left-right direction. Thus, the posture at the time of use of the heat exchanger 30 is not particularly limited. However, as described above, when the inner tube 35 and the outer tube 36 are arranged along the vertical direction, it is possible to easily discharge condensed water from the inner tube 35 and to release air from the liquid passing portion 33.

The hollow portion 32 of the heat exchanger 30 is the same as the above embodiment in that the sterilization tank 3 is connected to one end portion and the other end portion includes a protruding portion 34 outward from the liquid passing portion 33. . Therefore, in the said Example, the lower end part (downward) of the inner tube | pipe 35 or the outer tube | pipe 36 can be called one end part (one side), and the upper end part (upper part) of the inner tube | pipe 35 or the outer pipe | tube 36 is the other end part. It can be said that (the other).

In the above embodiment, the inner tube 35 includes the protruding portion 34 outward from the liquid passage portion 33, and the protruding portion 34 is covered by the extension tube portion 39 of the outer tube 36. The protruding portion 34 of the inner tube 35 is not covered by the extension tube portion 39 of the outer tube 36. That is, the extension pipe part 39 is not provided in the outer pipe 36. In this case, the gap between the outer tube 36 and the inner tube 35 is blocked by the end walls 40 and 41 at both ends in the axial direction. The heat exchanger 30 including the protruding portion 34 of the inner pipe 35 is preferably covered with a heat insulating material.

By the way, in the case of this modification, since the extension pipe part 39 is not provided in the outer pipe 36, the protruding part 34 of the inner pipe 35 is not cooled with water, so that the inner pipe 35 is likely to be subjected to thermal stress due to thermal expansion or thermal contraction. The inner tube 35 is welded to the end walls 40 and 41 at both ends in the longitudinal direction of the outer tube 36. Therefore, although the inner tube 35 is held by so-called both ends, thermal stress due to thermal expansion or contraction is likely to occur due to the loss of freedom. In that respect, in the case of the above-described embodiment, the protruding portion 34 of the inner tube 35 can be water-cooled, and the welded portion between the inner tube 35 and the outer tube 36 is one place. Thermal stress can be prevented.

The air leak detection device 1 of the present invention and the steam sterilization device 2 provided with the same are not limited to the configuration (including control) of the above embodiment, and can be changed as appropriate. In particular, (a) a heat exchanger 30 provided outside the sterilization tank 3 and having a hollow part 32 communicating with the inside of the sterilization tank 3 and having a liquid passage part 33 for exchanging heat with the fluid in the hollow part 32. And (b) determination means for determining the presence or amount of air leak into the sterilization tank 3 based on at least the outlet temperature among the inlet temperature, outlet temperature and flow rate of the liquid with respect to the liquid passing portion 33, (c ) As long as the hollow portion 32 is connected to the sterilization tank 3 at one end portion and provided with a protruding portion 34 outward from the liquid passing portion 33 at the other end portion, other structures can be appropriately changed. is there.

For example, in the above-described embodiment, the communication pipe 37 connecting the heat exchanger 30 and the sterilization tank 3 may be provided with an on-off valve as desired. In that case, for example, in the drying step, heat transfer from the sterilization tank 3 to the heat exchanger 30 can be prevented by closing the on-off valve.

Further, in the above-described embodiment, when the presence / absence or amount of air leak is being determined (during the sterilization process), if the detected temperature of the inlet temperature sensor 46 exceeds the upper limit temperature, the water supply is made desirable due to, for example, a failure of the water supply valve 49. It may be determined that it is not present, and the user may be informed accordingly.

DESCRIPTION OF SYMBOLS 1 Air leak detection apparatus 2 Steam sterilizer 3 Sterilization tank 4 Decompression means 5 Decompression means 6 Steam supply means 7 Drain discharge means 8 Exhaust means 28 Pressure sensor 29 Temperature sensor 30 Heat exchanger 31 Supply / drainage means 32 Hollow part 33 Fluid passage part 34 Projection part 35 Inner pipe 36 Outer pipe 37 Communication pipe 39 Extension pipe part 43 Water supply path 44 Drainage path 46 Inlet temperature sensor 47 Outlet temperature sensor 49 Water supply valve 50 Pressure reducing valve 51 Nozzle for flow rate adjustment

Claims (8)

1. After exhausting air from the sterilization tank, steam is supplied to the sterilization tank and used in a steam sterilization device that sterilizes the objects to be sterilized in the sterilization tank.
   A heat exchanger provided outside the sterilization tank, having a hollow portion communicating with the inside of the sterilization tank, and having a liquid passage portion for exchanging heat with the fluid in the hollow portion;
   Determination means for determining the presence or amount of air leak into the sterilization tank based on the inlet temperature, outlet temperature and flow rate of the liquid with respect to the liquid passing part;
   The hollow portion includes the sterilization tank connected to one end portion, and has a protruding portion outward from the liquid passing portion at the other end portion.
2. The heat exchanger includes an inner tube and an outer tube provided to surround the inner tube,
   The inner tube has one end extending outward from the outer tube and connected to the sterilization tank, so that the hollow hole of the inner tube communicates with the inside of the sterilization tank, while the other end is As the protruding portion, it extends outward from the outer tube and the extending tip is closed.
   Water as the liquid is passed through the liquid passing part formed of a cylindrical space between the inner pipe and the outer pipe,
   The air leak detection device according to claim 1, wherein a mouth portion for water supply / drainage with respect to the cylindrical space is provided on a peripheral side wall of the outer tube so as to be separated in a longitudinal direction of the outer tube.
3. The outer pipe is provided with an extension pipe part that covers the protruding part of the inner pipe,
   The air leak detection device according to claim 2, wherein a gap between the protruding portion of the inner tube and the extended tube portion of the outer tube communicates with the cylindrical space as the liquid passing portion.
4. The inner tube and the outer tube are arranged along an axis in the vertical direction,
   Of the mouth portions for water supply / drainage provided in the outer pipe, the lower mouth portion is a water supply port to the cylindrical space, while the upper mouth portion is a drainage port from the cylindrical space,
   The air leak detection device according to claim 2 or 3, wherein water is passed through the cylindrical space from below to above.
5. The liquid is passed through the liquid passage at a set flow rate,
   5. The determination unit according to claim 1, wherein the determination unit determines whether or not air leaks into the sterilization tank based on an inlet temperature and an outlet temperature of the liquid with respect to the liquid passing part. The described air leak detection device.
6. During sterilization of an object to be sterilized in the sterilization tank, the determination means determines the presence or absence or amount of air leak into the sterilization tank based on the temperature difference between the liquid outlet temperature and the inlet temperature with respect to the liquid passing part. The air leak detection device according to claim 5.
7. A steam sterilization apparatus comprising the air leak detection device according to any one of claims 1 to 6,
   A sterilization tank in which an object to be sterilized is stored and the air leak detection device is connected;
   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;
   A pressure sensor for detecting the pressure in the sterilization tank;
   A temperature sensor for detecting the temperature in the sterilization tank;
   Based on the detection signals of these sensors, the respective means are controlled to remove the air in the sterilization tank, the sterilization process for sterilizing an object to be sterilized with steam, and steam from the sterilization tank. A control means for sequentially executing an exhaust process for discharging the sterilization tank and a drying process for drying the sterilized material by depressurizing the interior of the sterilization tank,
   In the sterilization step, a liquid is passed through the heat exchanger of the air leak detection apparatus, and the presence or absence or amount of air leak into the sterilization tank is determined by the determination means.
8. In addition to the inlet temperature, outlet temperature and flow rate of the liquid with respect to the liquid passing part, the inlet temperature is the outlet temperature when the inlet temperature is not maintained at the set temperature, and the flow rate when the flow rate is not maintained at the set flow rate. Is also stored in the operation data storage means at predetermined intervals during the sterilization step,
   The steam sterilizer according to claim 7, wherein the data stored in the operation data storage means can be output to a predetermined device.

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