JP2010252880A - Steam sterilizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently discharge air from a jacket of a steam sterilizer in a short period of time. <P>SOLUTION: The seam sterilizer 1 has the jacket 3 disposed in such a way as to enclose a sterilizing tub 2. The jacket 3 heats the sterilization tub 2 from outside with steam fed by a steam feeding means 6. Condensed water of steam is discharged from the jacket 3 via a steam trap 7. A temperature regulating valve 16 is disposed in an exhaust line 15 from the jacket 3. The temperature regulating valve 16 is opened just after the start of feeding of steam into the jacket 3, but the valve is closed when the temperature within the jacket 3 rises as air is discharged from inside the jacket 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steam sterilizer that sterilizes medical instruments using steam. More specifically, the present invention relates to a steam sterilizer in which a jacket is provided so as to surround the sterilization tank, and steam is supplied into the jacket so that the inside of the sterilization tank is heated from the outside and maintained at a desired temperature.

  Conventionally, as disclosed in Patent Document 1 below, it is well known that a jacket is provided outside the sterilization tank, and the inside of the sterilization tank is maintained at a desired temperature by supplying steam into the jacket. Usually, the steam supply line into the jacket is connected to the upper part of the jacket, and the drain line from the jacket is connected to the lower part of the jacket. This drain line is provided with a steam trap, and drains out of the jacket.

  Further, as disclosed in Patent Document 2 below, in a reaction kettle or the like, a steam trap and a valve are provided in parallel in the discharge line from the lower part of the jacket, and the valve is opened when the steam heating temperature is lowered. It has also been proposed to improve responsiveness.

JP-A-9-122213 JP 2004-16034 A

  When trying to heat the sterilization tank by supplying steam into the jacket, if air is present in the jacket, it takes a long time to raise the temperature in order to inhibit the heat transfer of condensation from the steam to the sterilization tank. If it cannot be reliably eliminated, the inside of the jacket will not rise to the desired saturated steam temperature due to a decrease in the steam partial pressure. Therefore, it is necessary to quickly and surely remove air from the jacket.

  However, as disclosed in Patent Document 1, only by providing a drainage line provided with a steam trap, the air in the jacket passes through the steam trap together with the steam drain along with the steam supply into the jacket. Exhausted. Since the steam trap is usually provided in the pipe from the lowest position of the jacket, it cannot be exhausted well unless an air layer exists in the lowermost layer. Therefore, it takes time to exclude air from the jacket. In addition, since it is difficult for air to escape from the inside of the jacket, the inside of the jacket does not rise to the saturated steam temperature due to the partial pressure of air. When steam is supplied into the sterilization tank in such a state, the steam is condensed more than necessary in the sterilization tank. Therefore, it may take time to dry the sterilized material after sterilization, or the drying may be insufficient.

  Further, in the invention disclosed in Patent Document 2, the valve provided in parallel with the steam trap is opened when the steam heating temperature is lowered. Therefore, the air is exhausted quickly and reliably from the jacket. I can't.

  The problem to be solved by the present invention is to efficiently remove air from the jacket in a short time.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is directed to a sterilization tank in which an object to be sterilized is stored, a jacket provided so as to surround the sterilization tank, and an inside of the jacket. Steam supply means for supplying steam to the drain, drain discharge means for draining from the inside of the jacket via a steam trap, and before and / or immediately after the start of steam supply into the jacket, gas is supplied to the outside of the jacket. It is a steam sterilizer characterized by comprising exhaust means for discharging.

  According to the first aspect of the present invention, the jacket is provided not only with the drain discharge means but also with the exhaust means, and the exhaust means is outside the jacket before and / or immediately after the start of the steam supply into the jacket. Deriving gas. As a result, air can be quickly and reliably removed from the jacket, and even if steam is subsequently supplied into the sterilization tank, the steam is prevented from being condensed more than necessary. In other words, even if steam supply is started in the jacket, if air remains in the jacket, the temperature rise in the jacket will be very slow because it inhibits the condensation heat transfer of the steam. Such an inconvenience can be prevented by eliminating the air.

  The invention according to claim 2 is characterized in that the exhaust means is a means for deriving the gas in the jacket to the outside by a differential pressure from the atmospheric pressure immediately after the start of supply of steam into the jacket. The steam sterilizer according to claim 1.

  According to the second aspect of the present invention, air is expelled out of the jacket by the steam supplied into the jacket. In this way, air can be easily removed from the jacket.

  The invention according to claim 3 is characterized in that the exhaust means is a decompression means for sucking and discharging the gas in the jacket to the outside before the start of supply of steam into the jacket. The steam sterilizer described.

  According to the third aspect of the present invention, the air is forcibly excluded outside the jacket by the decompression means for sucking and discharging the gas in the jacket to the outside. In this way, air can be easily removed from the jacket.

  According to a fourth aspect of the present invention, the steam supply means is connected to an upper portion of the jacket, the exhaust means is connected to a side portion of the jacket, and the exhaust means is opened when air is removed from the jacket. The steam sterilizer according to claim 2, further comprising a valve.

  According to the fourth aspect of the present invention, by supplying steam from the upper part of the jacket and extracting air from the side part of the jacket, even if drain is accumulated in the lower part of the jacket, the air is surely excluded from the jacket. It can be carried out. And after the air is excluded from the jacket, the valve of the exhaust means may be closed.

  The invention according to claim 5 is the steam sterilizer according to claim 4, wherein the valve is a temperature regulating valve that opens and closes by itself based on the temperature of the gas passing through the valve.

  According to the fifth aspect of the present invention, the valve is opened at the beginning of the introduction of the steam into the jacket. However, when the jacket is filled with the steam, the valve is closed as the temperature rises. The configuration can eliminate air from the jacket.

  The invention according to claim 6 is the steam sterilizer according to claim 4, wherein the valve is controlled to open and close based on a detection signal of a sensor for detecting temperature or pressure in the jacket. .

  According to the sixth aspect of the present invention, the valve is open at the beginning of the introduction of the steam into the jacket, but when the jacket is filled with the steam, the temperature rise is detected by the sensor and the valve is closed. Thus, air can be excluded from the jacket with a simple configuration and control.

  The invention according to claim 7 is characterized in that the exhaust means is connected to a height occupying one third of the inner volume of the jacket from the bottom of the jacket. The steam sterilizer according to item.

  The average molecular weight of air is about 29, and the average molecular weight of steam (water) is about 18. Therefore, since air has a density 1.61 times that of steam (29/18 = 1.61), the weight of the air 1 is balanced by the volume of the steam 1.61. This is a relationship of 0.62 steam with 0.38 air when the total volume of air and steam is considered as 1. That is, the relationship is approximately 1/3 of air and 2/3 of steam. Considering this, in order to raise the temperature of the jacket, when steam is supplied from the upper part of the jacket and air is pushed out from the lower part of the jacket, the air is removed until one third of the inner volume of the jacket remains. At that stage (ie, about one third from the bottom is air and two thirds from the top is steam), the weight of the entire lower air and the entire upper steam will begin to reverse. . Therefore, if the exhaust means is provided at the lower part of the jacket, it is impossible to push out the air with steam. However, as in the invention according to claim 7, the volume from the bottom of the jacket is reduced to one third. Further, by providing the exhaust means, it is possible to reliably eliminate air from the jacket. This is particularly effective when the exhaust means is not a decompression means.

  Furthermore, in the invention according to claim 8, the exhaust gas is supplied to the inside of the jacket by the steam supply means in a state where the exhaust is stopped after the exhaust to the outside of the jacket before and / or immediately after the start of the steam supply into the jacket. The steam sterilization according to any one of claims 1 to 7, wherein the exhaust means exhausts the outside of the jacket at a predetermined timing even after the temperature inside the jacket is increased by supplying steam to the interior. It is a vessel.

  According to the eighth aspect of the present invention, the steam supply means is configured to perform exhaust to the outside of the jacket by the exhaust means at a predetermined timing even after the inside of the jacket has been heated by the supply of steam into the jacket from which air has been removed. Therefore, it is possible to eliminate air contained in the steam supplied into the jacket.

  According to the present invention, it is possible to efficiently remove air from the jacket in a short time.

It is the schematic which shows Example 1 of the steam sterilizer of this invention. It is the schematic which shows Example 2 of the steam sterilizer of this invention. It is the schematic which shows the modification of Example 2 of the steam sterilizer of this invention. It is a schematic perspective view which shows the inner cylinder and outer cylinder of each Example of the steam sterilizer of this invention. The relationship between the temperature in the jacket at a certain pressure and the density of the gas is shown, the solid line indicates steam and the broken line indicates air. It is a figure which shows the air exclusion state from the inside of a jacket in time series, and has shown the case where a jacket exhaust line is provided in the jacket bottom part. It is a figure which shows the air exclusion state from the inside of a jacket in time series, and has shown the case where a jacket exhaust line is provided in the jacket side part and the height of 1/3 from the bottom of a jacket internal volume. It is a figure which shows the temperature change in the jacket after the start of steaming into the jacket, and the broken line indicates the jacket drain discharge line and the jacket at the lower part of the jacket when the jacket drain discharge line is provided only at the lower part of the jacket. When the exhaust line is provided, the solid line indicates the case where the jacket drain discharge line is provided at the lower part of the jacket while the jacket exhaust line is provided at the jacket side.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing Example 1 of the steam sterilizer of the present invention. As shown in this figure, the steam sterilizer 1 includes a sterilization tank 2 in which an object to be sterilized is accommodated. The sterilization tank 2 is a hollow container that can withstand the decompression of the internal space, and is formed in a substantially rectangular box shape here. The sterilization tank 2 is provided with a door (not shown) for taking in and out the article to be sterilized on the front surface (the front side perpendicular to the paper surface). However, a door is provided on each of the front and back surfaces, one door is used as a carry-in door for putting a material to be sterilized in the sterilization tank 2, and the other door is used for taking out the material to be sterilized outside the sterilization tank 2 after sterilization. It is good also as a carry-out door. In either case, the door is closed so that the inside of the sterilization tank 2 can be sealed.

  The steam sterilizer 1 is provided with a jacket 3 as a hollow part into which steam is put in order to warm the inside of the sterilization tank 2 from the outside. In this embodiment, the jacket 3 is continuously provided on the upper, lower, left and right walls of the sterilization tank 2. Specifically, the steam sterilizer 1 includes a rectangular inner cylinder 4 and a rectangular outer cylinder 5 surrounding the inner cylinder 4 (FIG. 4). That is, the inner cylinder 4 is accommodated in the hollow hole of the outer cylinder 5, and the inner cylinder 4 and the outer cylinder 5 are arranged coaxially along the axis in the front-rear direction. Moreover, the clearance gap between the inner cylinder 4 and the outer cylinder 5 is obstruct | occluded in front and rear both end surfaces. Further, the inner cylinder 4 is provided with a door on one end surface (front surface) and the other end surface (rear surface) is closed with a flat plate or provided with a door as described above. In this way, the sterilization tank 2 is configured by the inner cylinder 4, and the jacket 3 is configured between the inner cylinder 4 and the outer cylinder 5.

  The jacket 3 includes steam supply means 6 for supplying steam into the jacket 3 (hereinafter referred to as jacket steam supply means), and drain discharge means 8 for discharging water from the jacket 3 through the steam trap 7 (hereinafter referred to as this). A jacket drain discharge means), an exhaust means 9 for deriving the gas in the jacket 3 to the outside by a differential pressure from the atmospheric pressure (hereinafter referred to as jacket exhaust means), and a pressure sensor 10 for detecting the pressure in the jacket 3 (Hereinafter referred to as a jacket pressure sensor).

  The jacket steaming means 6 introduces steam into the jacket 3 through the jacket steaming line 11. Specifically, the jacket steam supply means 6 introduces steam into the jacket 3 through a jacket steam supply line 11 from a steam supply source such as a boiler. The jacket steam supply line 11 is provided with a jacket steam supply valve 12. By opening and closing the jacket steam supply valve 12, the presence or absence of steam supply into the jacket 3 can be switched. The jacket steaming line 11 is preferably connected to the upper part of the jacket 3, more specifically to the upper part of the outer cylinder 5. At this time, the jacket steaming line 11 is preferably connected to the upper wall of the outer cylinder 5, but may be connected to the upper part of the side wall of the outer cylinder 5 in some cases.

  The jacket drain discharge means 8 drains the drain from the jacket 3 through the steam trap 7. Specifically, the jacket drain discharge means 8 guides the drain generated in the jacket 3 through the jacket drain discharge line 13. The jacket drain discharge line 13 is provided with a steam trap 7 and a check valve 14 in order from the jacket 3 side. The jacket drain discharge line 13 is preferably connected to the lower part of the jacket 3, more specifically to the bottom wall of the outer cylinder 5.

  In this embodiment, the jacket exhaust means 9 guides the gas in the jacket 3 to the outside by a differential pressure from the atmospheric pressure. Specifically, the jacket exhaust means 9 guides the gas in the jacket 3 out of the jacket 3 via the jacket exhaust line 15. In particular, by introducing steam into the jacket 3, the air is expelled from the jacket 3 through the jacket exhaust line 15. The jacket exhaust line 15 is provided with a jacket exhaust valve 16 and a check valve 17 in order from the jacket 3 side. The jacket exhaust valve 16 of the present embodiment is a temperature adjustment valve that opens and closes by itself based on the temperature of the gas passing through the valve. Specifically, as the jacket exhaust valve 16, a thermo valve whose operating temperature (temperature when closing) is 100 ° C., for example, is used. The jacket exhaust line 15 is preferably connected above the bottom of the jacket 3. In other words, the opening from the jacket 3 to the jacket exhaust line 15 is preferably disposed above the opening from the jacket 3 to the jacket drain discharge line 13. In the present embodiment, the jacket exhaust line 15 is connected to the side portion of the jacket 3, more specifically to the side wall of the outer cylinder 5.

  The outer cylinder 5 is provided with a jacket pressure sensor 10 that detects the pressure in the jacket 3. The installation position of the jacket pressure sensor 10 is not particularly limited, but is provided on the upper side portion of the jacket 3 as shown in the illustrated example. In the case of saturated steam, the pressure and the temperature are in a predetermined relationship, so that instead of or in addition to the jacket pressure sensor 10 that detects the pressure in the jacket 3, the jacket temperature that detects the temperature in the jacket 3. A sensor (not shown) may be used.

  The inner cylinder 4, that is, the sterilization tank 2, is a sterilization tank in which the gas in the sterilization tank 2 is sucked and discharged to the outside to decompress the sterilization tank 2 and outside air is introduced into the decompressed sterilization tank 2. The pressure-recovering means 19 for returning the pressure in the tank 2, the steam supply means 20 for supplying steam into the sterilization tank 2 (hereinafter referred to as “sterilization tank steaming means”), and drainage from the sterilization tank 2 through the steam trap 21. Drain discharge means 22 (hereinafter referred to as sterilization tank drain discharge means), and exhaust means 23 (hereinafter referred to as sterilization tank exhaust means) for deriving the gas in the sterilization tank 2 to the outside by a differential pressure from the atmospheric pressure. And a pressure sensor 24 for detecting the pressure in the sterilization tank 2 (hereinafter referred to as “sterilization tank pressure sensor”) and a temperature sensor 25 for detecting the temperature in the sterilization tank 2 (hereinafter referred to as “sterilization tank temperature sensor”). It is done.

  The decompression means 18 decompresses the inside of the sterilization tank 2 by sucking and discharging the gas in the sterilization tank 2 to the outside. Specifically, the decompression means 18 sucks and discharges the gas in the sterilization tank 2 through the vacuum line 26. The vacuum line 26 is provided with a vacuum valve 27 and a water-sealed vacuum pump 28 in order from the sterilization tank 2 side. However, instead of or in addition to the vacuum pump 28, an ejector may be used, or a heat exchanger may be provided between the vacuum valve 27 and the vacuum pump 28. In this heat exchanger, cooling water is supplied and discharged, and the water and steam in the vacuum line 26 are indirectly heat-exchanged to cool and condense the steam in the vacuum line 26.

  As is well known, the water-sealed vacuum pump 28 is operated by supplying water called sealed water. For this purpose, water is supplied to the vacuum pump 28 via a sealed water supply valve 29 and discharged. When the vacuum pump 28 is operated, the sealed water supply valve 29 is opened in conjunction with the operation of the vacuum pump 28.

  The decompression means 19 introduces outside air into the sterilization tank 2 under reduced pressure to restore the pressure in the sterilization tank 2. Specifically, the return pressure means 19 introduces outside air into the sterilization tank 2 under reduced pressure via the air supply line 30. The air supply line 30 is provided with a sterile filter 31, an air supply valve 32, and a check valve 33 in order toward the sterilization tank 2. When the air supply valve 32 is opened in a state where the inside of the sterilization tank 2 is depressurized, the outside air is introduced into the sterilization tank 2 by the differential pressure, and the inside of the sterilization tank 2 can be restored.

  The sterilization tank steaming means 20 introduces steam into the sterilization tank 2 via the sterilization tank steaming line 34. Specifically, the sterilization tank steaming means 20 introduces steam into the sterilization tank 2 via a sterilization tank steaming line 34 from a steam supply source such as a boiler. The sterilization tank steaming line 34 is provided with a sterilization tank steaming valve 35. By opening and closing the sterilization tank steaming valve 35, the presence or absence of steam supply into the sterilization tank 2 can be switched. The steam supplied into the sterilization tank 2 via the sterilization tank steaming line 34 and the steam supplied into the jacket 3 via the jacket steaming line 11 are steam from the same steam supply source. It is easy to do. However, the steam supplied into the sterilization tank 2 may be different from the steam supplied into the jacket 3. For example, steam from the boiler is supplied as it is into the jacket 3, but pure water may be vaporized into the sterilization tank 2 using steam from the boiler as a heat source, and clean steam thereby may be supplied.

  The sterilization tank drain discharge means 22 discharges water from the sterilization tank 2 through the steam trap 21. Specifically, the sterilization tank drain discharge means 22 guides the drain generated in the sterilization tank 2 to the outside of the sterilization tank 2 through the sterilization tank drain discharge line 36. On the other hand, the sterilization tank exhaust means 23 guides the gas in the sterilization tank 2 to the outside by a differential pressure from the atmospheric pressure. Specifically, the sterilization tank exhaust means 23 guides the gas in the sterilization tank 2 out of the sterilization tank 2 via the sterilization tank exhaust line 37.

  In the illustrated example, the sterilization tank drain discharge line 36 and the sterilization tank exhaust line 37 are unified as common lines 38 and 39 on the upstream side and the downstream side. A sterilization tank drain discharge line 36 and a sterilization tank exhaust line 37 are provided in parallel between the upstream and downstream common lines 38 and 39. Among them, the sterilization tank drain discharge line 36 is provided with a steam trap 21 and a check valve 40 in order from the upstream side, and the sterilization tank exhaust line 37 is provided with a sterilization tank exhaust valve 41 and a check valve 42. As for the sterilization tank drain discharge line 36 and the sterilization tank exhaust line 37, an upstream common line 38 is connected to the bottom of the sterilization tank 2. The downstream common line 39 is provided with a check valve 43, and immediately before that, a discharge line 44 from the vacuum pump 28 is connected via a check valve 45, and the jacket exhaust line 15 The end is also connected. Further, the downstream end of the jacket drain discharge line 13 is connected to the downstream common line 39 on the downstream side of the check valve 43 provided there.

  The sterilization tank 2 is provided with a sterilization tank pressure sensor 24 that detects the pressure in the sterilization tank 2 and a sterilization tank temperature sensor 25 that detects the temperature in the sterilization tank 2. Although the installation position of the sterilization tank pressure sensor 24 is not particularly limited, for example, it is provided on the upper side of the sterilization tank 2 as shown in the drawing. On the other hand, the sterilization tank temperature sensor 25 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 common lines 38 of an upstream side.

  The steam sterilizer 1 further includes control means (not shown). The control means is based on the detection signals of the sensors 10, 24, 25, the elapsed time, and the like, in addition to the decompression means 18, the decompression means 19, the sterilization tank steaming means 20, the jacket steaming means 6, and the sterilization tank exhaust means. 23 is a controller (not shown) for controlling the control unit 23 and the like. The controller then sterilizes the object to be sterilized in the sterilization tank 2 according to a predetermined procedure (program).

  In order to sterilize the object to be sterilized in the sterilization tank 2, the control of the environment in the sterilization tank 2 is set as appropriate. Typically, after removing air from the sterilization tank 2, the sterilization tank 2 is maintained at a predetermined temperature with saturated steam for a predetermined time to sterilize the sterilization object, and then the sterilization object is dried. Plan.

  For example, after the sterilization tank steam supply valve 35 and the sterilization tank exhaust valve 41 are opened and the steam is circulated in the sterilization tank 2 with the decompression means 18 stopped, The sterilization tank supply valve 35 and the sterilization tank exhaust valve 41 are closed, the vacuum valve 27 is opened, and the inside of the sterilization tank 2 is decompressed by the decompression means 18. Next, the vacuum valve 27 is closed and the decompression means 18 is stopped, the sterilization tank steaming valve 35 is opened, steaming is performed until the pressure in the sterilization tank 2 is close to atmospheric pressure, the vacuum valve 27 is opened again and the pressure is reduced. The means 18 is operated to depressurize the sterilization tank 2. Such decompression and steaming are repeated a plurality of times.

  Thereafter, the vacuum valve 27 is closed, the decompression means 18 is stopped, the sterilization tank steam supply valve 35 is opened, the inside of the sterilization tank 2 is pressurized with steam, and the sterilization process is started. In this sterilization process, the temperature in the sterilization tank 2 is monitored by the sterilization tank temperature sensor 25, and the opening and closing of the sterilization tank steam supply valve 35 is controlled so as to maintain the sterilization temperature for a predetermined sterilization holding time. As a result, the article to be sterilized in the sterilization tank 2 is maintained at the sterilization temperature for the sterilization holding time and sterilized.

  Then, while the sterilization tank steam supply valve 35 is closed, the sterilization tank exhaust valve 41 is opened and the steam is discharged out of the sterilization tank 2, and then the sterilized material is dried for a set time. For example, the inside of the sterilization tank 2 is depressurized to a predetermined pressure by the decompression means 18, and the object to be sterilized in the sterilization tank 2 is dried by maintaining the reduced pressure.

  As described above, the steam sterilizer 1 is sequentially subjected to the air evacuation process from the inside of the sterilization tank 2, the sterilization process of the sterilization object, and the drying process of the sterilization object. The inside of the jacket 3 is maintained at a desired temperature by the supply of steam to the, and the maintenance control is continued during a series of operations from the air exclusion process to the drying process.

  By supplying steam into the jacket 3, heat radiation from the sterilization tank 2 can be suppressed and the desired temperature can be easily maintained. At the start of steam introduction into the jacket 3, air is present in the jacket 3. Since most of the air is a non-condensable gas, the temperature rise of the jacket 3 becomes very slow because the condensation heat transfer by the steam to the inner cylinder 4 and the outer cylinder 5 is hindered.

  For this reason, it is necessary to exhaust the air in the jacket 3 as follows. That is, when the introduction of steam into the jacket 3 is started, the jacket exhaust valve 16 is open because the temperature in the jacket 3 is low. Therefore, when the jacket steam supply valve 12 is opened and steam is supplied into the jacket 3, the air in the jacket 3 is pushed out to the jacket exhaust line 15.

  In this way, as air is removed from the jacket 3, the temperature of the gas passing through the jacket exhaust valve 16 increases. The jacket exhaust valve 16 is closed by itself when the temperature of the gas passing therethrough is a predetermined temperature (the temperature reached when the air in the jacket 3 is removed). Thereafter, the jacket steam supply valve 12 is controlled so that the pressure detected by the jacket pressure sensor 10 is kept constant in a state where the exhaust from the jacket exhaust line 15 is blocked. During this time, the steam drain supplied into the jacket 3 is discharged from the jacket drain discharge line 13 via the steam trap 7.

  According to the present embodiment, while supplying steam into the jacket 3, the non-condensable gas that obstructs heat transfer can be removed out of the jacket 3, so the temperature of the jacket 3 (the wall surface temperature of the sterilization tank 2). Can be raised to a predetermined temperature in a short time. In addition, since the jacket exhaust line 15 is opened and closed depending on the temperature using a temperature adjustment valve as the jacket exhaust valve 16, it is possible to prevent excessive outflow of steam from the jacket 3.

  By the way, as a modification of the first embodiment, in FIG. 1, an electromagnetic valve or an electric valve may be used as the jacket exhaust valve 16 instead of the temperature adjustment valve. Also in this case, the jacket exhaust valve 16 may be opened when air is exhausted from the jacket 3. For example, immediately after the start of steam supply into the jacket 3, the jacket exhaust valve 16 is opened, the steam within the jacket 3 is expelled with steam, and a predetermined time required to eliminate air from the jacket 3 has elapsed. The jacket exhaust valve 16 may be closed later.

  Alternatively, the opening / closing of the jacket exhaust valve 16 may be controlled based on the detection signal of the jacket pressure sensor 10 that detects the pressure in the jacket 3 and / or the jacket temperature sensor that detects the temperature in the jacket 3. For example, when the jacket exhaust valve 16 is opened at the beginning of the introduction of steam into the jacket 3 and the steam is introduced into the jacket 3 and the air is exhausted from the jacket 3 as a result, the pressure in the jacket 3 and As the temperature rises, the pressure or temperature may be detected and the controller may control to close the jacket exhaust valve 16.

  FIG. 2 is a schematic view showing Example 2 of the steam sterilizer 1 of the present invention. The steam sterilizer 1 according to the second embodiment is basically the same as the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the first embodiment, the jacket exhaust valve 15 is provided in the jacket exhaust line 15, but in the second embodiment, the jacket exhaust line 15 is provided with a vacuum pump 28 via the jacket exhaust valve 16. As this vacuum pump 28, the same vacuum pump 28 as the decompression means 18 connected to the sterilization tank 2 can be used. That is, in the illustrated example, the sterilization tank 2 is connected to the vacuum pump 28 via the vacuum valve 27 and the check valve 46, and the jacket 3 is connected via the jacket exhaust valve 16. In FIG. 2, the jacket exhaust line 15 is connected to the side of the jacket 3, but the jacket exhaust line 15 may be connected to the bottom of the jacket 3 as shown in FIG. 3.

  In the case of the second embodiment, before starting the supply of steam into the jacket 3, the vacuum pump 28 is operated in a state where the jacket exhaust valve 16 is opened, so that air is excluded from the jacket 3. After such air exclusion is performed for a predetermined time or the pressure in the jacket 3 is lowered to a predetermined value, the jacket exhaust valve 16 is closed and the jacket steam supply valve 12 is opened to supply steam into the jacket 3. Thereafter, as in the first embodiment, the jacket steam supply valve 12 is controlled based on the detected pressure of the jacket pressure sensor 10 to keep the inside of the jacket 3 at a desired pressure. Other configurations and controls are the same as those in the first embodiment, and a description thereof will be omitted.

  By the way, in each of the above-described embodiments, particularly in the first embodiment and the modification thereof, the connection position of the jacket exhaust line 15 to the jacket 3 is a side portion of the jacket 3 that is as high as 1/3 from below the inner volume of the jacket. It is preferable that Specifically, the opening from the jacket 3 to the jacket exhaust line 15 is preferably at the side of the outer cylinder 5 at a height that occupies one-third of the inner volume of the jacket from the bottom of the outer cylinder 5.

  FIG. 4 is a schematic perspective view showing the inner cylinder 4 and the outer cylinder 5 of the steam sterilizer 1 of each embodiment. As described above, the inner cylinder 4 and the outer cylinder 5 are formed in a substantially rectangular box shape, and the inner cylinder 4 is accommodated in the outer cylinder 5 with a gap left and right and up and down. As described above, the inner cylinder 4 opens forward and backward, but a door is provided at the front opening, and the rear opening is closed by a plate material or provided with a door. Further, the gap between the inner cylinder 4 and the outer cylinder 5 is closed in the front-rear direction.

Ignoring the plate thicknesses of the inner cylinder 4 and the outer cylinder 5, for example, the left-right method width dimension W of the inner cylinder 4 is 660 mm, and the left-right width dimension W ′ of the gap between the inner cylinder 4 and the outer cylinder 5 is 100 mm, respectively. The vertical dimension H of the inner cylinder 4 is 1450 mm, the vertical dimension H ′ of the gap between the inner cylinder 4 and the outer cylinder 5 is 60 mm, and the depth D in the front-rear direction of the inner cylinder 4 and the outer cylinder 5 is D. 1250 mm. In this case, the total volume in the jacket 3 between the inner cylinder 4 and the outer cylinder 5 is {0.06 × (0.66 + 0.1 × 2) × 1.25 × 2} + {0.1 × 1. .45 × 1.25 × 2} = 0.129 + 0.36, which is 0.49 m ³ . Therefore, one third of the inner volume of the jacket is 0.16 m ³ as 0.49 / 3. And the height which occupies 1/3 of the jacket internal volume from the bottom part of an outer cylinder is set to {. 38m. That is, in this example, it is preferable to provide the jacket exhaust line 15 at a location 380 mm higher than the bottom surface of the outer cylinder 5. When the rear surfaces of the inner cylinder 4 and the outer cylinder 5 are also the jacket 3, the connection position of the jacket exhaust line 15 is calculated including the volume thereof.

  Next, the reason why the height of one-third of the inner volume of the jacket is good in the first place will be described. FIG. 5 shows the relationship between the temperature in the jacket 3 at a certain pressure and the density of the gas. The solid line indicates steam and the broken line indicates air. It is assumed that the pressure in the jacket 3 gradually increases due to the supply of steam into the jacket 3, for example, 0.1 MPa. Under the present circumstances, the density of the vapor | steam shown as a continuous line increases, and the temperature in the jacket 3 increases, so that the density of the air shown with a broken line is low. In this case, the steam is heavier when the temperature is higher than the temperature at which the broken line and the solid line intersect (here, 106 ° C.), and the air is heavier when the temperature is lower than that temperature. This branch point is determined by the partial pressure of air, and the ratio of the mixed gas in the jacket 3 is about 38% air and about 62% steam. That is, when about 2/3 of the whole air is removed and replaced with steam, the steam becomes heavier.

  The reason why one third of the inner volume of the jacket is good can also be explained from the following points. That is, first, it is known that the average molecular weight of air is about 29, and the average molecular weight of steam (water) is about 18. Therefore, since air has a density 1.61 times that of steam (29/18 = 1.61), the weight of the air 1 is balanced by the volume of the steam 1.61. This is a relationship of 0.62 steam with 0.38 air when the total volume of air and steam is considered as 1. That is, the relationship is approximately 1/3 of air and 2/3 of steam.

  FIGS. 6 and 7 are diagrams showing the state of exhausting air from the jacket 3 in time series. FIG. 6 shows the case where the jacket exhaust line 15 is provided at the bottom of the jacket 3, and FIG. The case where it is provided at the height of one third from the bottom of the inner volume of the jacket is shown. Moreover, in each figure, the hatching part has shown the air and the dot part has shown the vapor | steam.

  As shown in FIG. 6, when the jacket exhaust line 15 is provided at the bottom of the jacket 3, when steam is supplied from the top of the jacket 3, as shown in FIGS. Is expelled from below. However, as described above, the steam becomes heavier when 2/3 of the jacket internal volume is released. As a result, as shown in (d) and (e) of the figure, the air moves upward and the steam moves downward, so that the air and the steam are mixed as shown in (f) of the figure. Therefore, the air rejection efficiency is inferior.

  On the other hand, as shown in FIG. 7, when the jacket exhaust line 15 is provided at a height of one third of the inner volume of the jacket, when steam is supplied from the upper part of the jacket 3, (b) and (c) of FIG. ), The air in the jacket 3 is the same in that it is expelled to the jacket exhaust line 15, but the rest is different from FIG. 6. That is, when 2/3 of the jacket internal volume is released, the steam becomes heavier as described above, but the jacket exhaust line 15 is provided at a height of 1/3 of the jacket internal volume. As shown in FIGS. 5D to 5F, the jacket 3 is filled with steam while air is removed from the jacket exhaust line 15. Therefore, the air removal efficiency is improved by providing it at one-third height of the inner volume of the jacket.

  FIG. 8 is a diagram showing a temperature change in the jacket 3 after the start of steaming into the jacket 3. The broken line indicates the jacket drain discharge line 13 only at the lower part of the jacket 3, and the two-dot chain line indicates the jacket 3. 3, when the jacket drain discharge line 13 and the jacket exhaust line 15 are provided at the lower part, the solid line indicates that the jacket drain discharge line 13 is provided at the lower part of the jacket 3, while the jacket 3 side part (from the jacket bottom to a third of the jacket internal volume). The case where the jacket exhaust line 15 is provided at the same height) is shown.

  In any case, the temperature in the jacket 3 rises due to the steam supply into the jacket 3. However, when only the jacket drain discharge line 13 is provided at the lower part of the jacket 3 (broken line), or when the jacket exhaust line 15 is provided at the lower part of the jacket 3 (two-dot chain line), the temperature inside the jacket 3 is at a certain level. When the temperature rises, the steam is mixed with the air remaining in the jacket 3, and the amount of condensation is reduced, so that the temperature is temporarily lowered. Thereafter, the temperature in the jacket 3 starts to rise again as air escapes from the bottom together with the drain.

  Here, even when the jacket exhaust line 15 is provided at the lower part of the jacket 3 (one-dot chain line), the increase in temperature is slow and the decrease is remarkable, indicating that the air cannot be removed only from the lower part of the jacket 3. Since the vapor trap 7 is open as long as liquid is present, air is discharged together with the drain, and therefore, the case where the jacket exhaust line 15 is provided below the jacket 3 (two-dot chain line) is not provided (dashed line). ) Has a larger initial temperature rise, but after that, when steam and air are mixed, the gas does not escape, so the temperature rise slows down.

  On the other hand, when the jacket drain discharge line 13 is provided at the lower part of the jacket 3 and the jacket exhaust line 15 is provided on the side of the jacket 3 (solid line), the jacket 3 is surely ventilated. The temperature inside rises to the right. Thus, according to the present invention, air can be efficiently removed from the jacket 3 in a short time.

  The steam sterilizer 1 of the present invention is not limited to the configuration of each of the above embodiments, and can be changed as appropriate. In particular, other configurations and controls can be appropriately changed as long as the gas is led out of the jacket 3 before and / or immediately after the start of steam supply into the jacket 3.

  In each of the above-described embodiments, the air exhaust to the outside of the jacket 3 before and / or immediately after the start of the steam supply into the jacket 3 has been described. In addition to this, the jacket exhaust means 9 moves outside the jacket 3. In the state where the exhaust gas of the jacket 3 is stopped, the steam supply to the jacket 3 by the jacket steam supply means 6 raises the inside of the jacket 3 to a desired temperature (or pressure). Exhaust may be performed at a predetermined timing. For example, the jacket exhaust valve 16 may be opened and closed periodically. Thereby, the air (non-condensable gas) contained in the steam supplied into the jacket 3 by the jacket steam supply means 6 can also be eliminated.

DESCRIPTION OF SYMBOLS 1 Steam sterilizer 2 Sterilization tank 3 Jacket 4 Inner cylinder 5 Outer cylinder 6 Steaming means (jacket steaming means)
7 Steam trap 8 Drain discharge means (jacket drain discharge means)
9 Exhaust means (jacket exhaust means)
10 Jacket pressure sensor 16 Jacket exhaust valve (temperature control valve, etc.)
18 Pressure reducing means

Claims (8)

A sterilization tank in which objects to be sterilized are stored;
A jacket provided to surround the sterilization tank;
Steaming means for supplying steam into the jacket;
Drain discharge means for draining from the jacket through a steam trap;
A steam sterilizer comprising: exhaust means for leading gas out of the jacket before and / or immediately after the start of steam supply into the jacket. 2. The steam sterilization according to claim 1, wherein the exhaust unit is a unit that guides the gas in the jacket to the outside by a differential pressure from the atmospheric pressure immediately after the start of steam supply into the jacket. vessel. 2. The steam sterilizer according to claim 1, wherein the exhaust unit is a decompression unit that sucks and discharges the gas in the jacket to the outside before the start of steam supply into the jacket. The steaming means is connected to the upper part of the jacket,
The exhaust means is connected to a side of the jacket;
The steam sterilizer according to claim 2, wherein the exhaust means includes a valve that is opened when air is removed from the jacket. The steam sterilizer according to claim 4, wherein the valve is a temperature regulating valve that opens and closes by itself based on a temperature of a gas passing through the valve. The steam sterilizer according to claim 4, wherein the valve is controlled to open and close based on a detection signal of a sensor that detects a temperature or pressure in the jacket. The steam sterilizer according to any one of claims 1 to 6, wherein the exhaust unit is connected to a height that occupies a third of the inner volume of the jacket from the bottom of the jacket. After exhausting the jacket outside before and / or immediately after the start of steam supply into the jacket, the temperature inside the jacket is raised by steam supply into the jacket by the steam supply means while the exhaust is stopped. The steam sterilizer according to any one of claims 1 to 7, wherein the exhaust to the outside of the jacket by the exhaust means is performed at a predetermined timing.

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