Steam sterilizer

Abstract

To provide a steam sterilizer capable of reducing a magnitude of sound generated when steam is exhausted from a high pressure chamber.SOLUTION: The steam sterilizer according to the present invention includes a chamber 10 capable of accommodating an object to be sterilized, a heater for heating a liquid, a liquid storage tank 20, a drain pipe, a first on-off valve 44, an exhaust pipe 42, a second on-off valve 45, a common pipe 43, and a control unit. The control unit is configured such that, after sterilizing the object to be sterilized, it opens the first on-off valve to start discharging the liquid through the drain pipe, and then opens the second on-off valve to start discharging gas through the exhaust pipe. The drain pipe has a first portion 411 connecting the chamber and the first on-off valve, and a second portion 412 connecting the first on-off valve and the common pipe, the second portion being formed longer than the shortest distance between the first on-off valve and the common pipe.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a steam sterilizer. [Background technology]

[0002] Patent Document 1 discloses a steam sterilizer. This steam sterilizer is configured to heat water supplied from a water tank to a chamber in the chamber, and use the generated steam to sterilize medical equipment and other items placed in the chamber. After sterilization is complete, the water and steam accumulated in the chamber are discharged into the water tank. A condenser unit is submerged in the liquid phase of the water tank, which lowers the temperature of the water and steam flowing from the chamber to the water tank. This reduces noise when the water and steam are discharged into the water tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-112654 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned problems, and aims to provide a steam sterilizer that can further reduce the volume of noise generated when water or steam is discharged from a high-pressure chamber. [Means for solving the problem]

[0005] Item 1. A chamber capable of accommodating an object to be sterilized; a heater for heating the liquid supplied into the chamber; A liquid storage tank; a drain for draining liquid from the chamber; a first on-off valve provided in the drainage pipe; an exhaust pipe for discharging gas from the chamber; a second on-off valve provided in the exhaust pipe; a common pipe for sending the liquid discharged from the drain pipe and the gas discharged from the exhaust pipe to the liquid storage tank; A control unit; Equipped with the control unit is configured to, after sterilization of the object to be sterilized, open the first on-off valve to start discharging the liquid from the drain pipe, and then open the second on-off valve to start discharging the gas from the exhaust pipe; the drain pipe has a first portion connecting the chamber and the first on-off valve, and a second portion connecting the first on-off valve and the common pipe; The second portion is formed to be longer than the shortest distance between the first on-off valve and the common pipe. Steam sterilizer.

[0006] Item 2. The length of the second portion is at least twice the shortest distance. Item 1. A steam sterilizer as described in item 1.

[0007] Item 3. At least a portion of the second portion is formed of a flexible material. Item 1 or 2. A steam sterilizer.

[0008] Item 4. At least a portion of the second portion is curved. Item 4. The steam sterilizer according to any one of items 1 to 3.

[0009] Item 5. The inner diameter of the second portion is smaller than the inner diameter of the first portion. Item 5. A steam sterilizer according to any one of items 1 to 4.

[0010] Item 6. The inner diameter of the second portion is 2.0 to 3.0 mm. Item 6. A steam sterilizer according to any one of items 1 to 5.

[0011] Item 7. The control unit is configured to open the second on-off valve to start discharging the gas from the exhaust pipe while the liquid is being discharged from the drain pipe. Item 7. The steam sterilizer according to any one of items 1 to 6. [Effects of the Invention]

[0012] The steam sterilizer according to the present invention can reduce the volume of the noise generated when steam is discharged from the high-pressure chamber. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing the configuration of a sterilizer according to an embodiment of the present invention. FIG. [Figure 2] FIG. 4 is a cross-sectional view showing the configuration of a rising portion. [Figure 3] FIG. 10 is a side view of a portion of the discharge path. [Figure 4] FIG. [Figure 5] FIG. 2 is a block diagram showing the electrical configuration of the sterilizer of FIG. 1. [Figure 6] FIG. 4 is a diagram showing a display on a display unit of an operation panel. [Figure 7] FIG. 4 is a diagram showing a display on a display unit of an operation panel. [Figure 8] FIG. 4 is a diagram showing a display on a display unit of an operation panel. [Figure 9] FIG. 4 is a diagram showing a display on a display unit of an operation panel. [Figure 10] FIG. 4 is a diagram showing a display on a display unit of an operation panel. [Figure 11] 10 is a timing chart showing the operation of each device in the sterilizer (cooling water supply process (1)). [Figure 12] 10 is a timing chart showing the operation of each device in the sterilizer (cooling water supply process (2)). [Figure 13] 10 is a timing chart showing the operation of each device in the sterilizer (cooling water supply process (3)). [Figure 14] 10 is a flowchart of a cooling water supply process. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the sterilizer according to the present invention will now be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a sterilizer 1 of this embodiment. As shown in Figure 1, the sterilizer 1 of this embodiment sterilizes an object to be sterilized 100, such as gauze, scalpels, and other medical instruments, and comprises a chamber 10, a water tank 20, various pipes connected to the chamber 10 and the water tank 20, and a control unit 80 (see Figure 5), all of which are housed in a housing. In addition, an operation panel 7 for operating the sterilizer is provided on the side of the housing. These components will be described in detail below.

[0015] <1. Sterilizer structure> <1-1. Chamber> As shown in Figure 1, chamber 10 has a cylindrical internal space 101 that extends horizontally, and an open / close lid 11 is provided at one axial end of internal space 101. By opening open / close lid 11, it is possible to carry in and out objects to be sterilized 100 into internal space 101. On the other hand, by closing open / close lid 11, internal space 101 is kept sealed.

[0016] A sterilization heater 12 is installed near the bottom surface of the internal space 101. The sterilization heater 12 is arranged to extend along the bottom surface of the internal space 101. The sterilization heater 12 heats water supplied into the chamber 10 to generate steam, and the object 100 to be sterilized is sterilized with this steam.

[0017] Water is an example of a liquid that is supplied for sterilization into the chamber 10. The water may be tap water, distilled water, or purified water.

[0018] A drying heater 14 is installed on the upper surface of the chamber. The drying heater 14 is arranged so as to extend along the outer periphery of the upper surface of the chamber. The drying heater 14 is provided to heat the internal space from the outside of the chamber 10 and dry the inside of the chamber 10.

[0019] The internal space 101 is provided with a table 13 on which an object to be sterilized 100 can be placed, and the table 13 is provided approximately parallel to the bottom surface.

[0020] A first temperature sensor 16 that detects the temperature inside the chamber 10 is attached to the inner end of the internal space 101 (the end opposite the opening / closing lid 11). The temperature sensor 16 measures the temperature of the gas in the internal space 101. A second temperature sensor 17 is provided on the bottom surface of the internal space 101 and measures the temperature near the sterilization heater 12. A third temperature sensor 18 is provided on the top surface of the chamber 10 and measures the temperature near the drying heater 14.

[0021] <1-2. Water tank> Water tank 20 stores water supplied to chamber 10. Water discharged from chamber 10 returns to water tank 20. Water tank 20 stores water discharged from chamber 10. The internal space of water tank 20 includes a liquid phase section 21 in which water exists and a gas phase section 22 in which air exists. A water level sensor 26 for detecting the water level in water tank 20 is installed in the internal space of water tank 20.

[0022] <1-3. Routes of piping, etc.> The chamber 10 and the water tank 20 are connected by a water supply path 30 and a discharge path 40. The water supply path 30 is a path for supplying water from the water tank 20 to the chamber 10, and also serves as an overflow path as described below. The discharge path 40 is a path for discharging water, water vapor, and air from the chamber 10 to the water tank 20. In addition, an air supply path 60 for supplying air to the chamber 10 is connected to the chamber 10. Note that each of the pipe members 31, 33, 41, 42, 43, 51, 61, and 65 described below is formed of a flexible resin material.

[0023] <1-3-1. Water supply route> The water supply path 30 includes a water supply pipe 31, a water supply pump 32, and a water supply solenoid valve 33. One end of the water supply pipe 31 is connected to the inside of the water tank 20, and the other end is connected to the bottom of the chamber 10. The water supply pump 32 is provided on the upstream side of the water supply pipe 31 (the side closer to the water tank 20). The water supply solenoid valve 33 is provided downstream of the water supply pump 32 and on the downstream side of the water supply pipe 31 (the side closer to the chamber 10). An overflow sensor 54, which will be described later, is provided on the water supply pipe 31 between the water supply pump 32 and the water supply solenoid valve 33. The water supply solenoid valve 33 is a normally closed solenoid valve that opens when on (energized), and the other solenoid valves 44, 45, and 62 have the same specifications.

[0024] The water supply pipe 31 has a first water supply pipe 31a at a portion connected to the water tank 20 and the overflow sensor 54, and a second water supply pipe 31b at a portion connected to the overflow sensor 54 and the bottom of the chamber 10. As will be described later, the second water supply pipe 31b also serves as an overflow path.

[0025] The water supply pump 32 transfers water in a flow direction from the water tank 20 toward the chamber 10, thereby supplying water into the chamber 10. The water supply electromagnetic valve 33 opens and closes the water supply path 30, and is switchable between an open state in which water can flow from the water tank 20 to the chamber 10, and a closed state in which water is prohibited from flowing from the water tank 20 to the chamber 10. As will be described later, the water supply electromagnetic valve 33 also serves as a solenoid valve for the overflow path, and is therefore also used to switch between an open state in which water can flow from the chamber 10 to the water tank 20, and a closed state in which water is prohibited from flowing from the chamber 10 to the water tank 20.

[0026] The water supply pipe 31 (second water supply pipe 31b) has a cylindrical rising portion 52 at its end where it is connected to the chamber 10, protruding from below into the internal space of the chamber 10. As shown in FIG. 2, a chamfered surface 58 is formed on the outer periphery of the upper end of the rising portion 52, and a chamfered surface 59 is also formed on the inner periphery. In addition, a dome-shaped net-like mesh member 90 is attached by brazing or the like to the end face of the upper end of the rising portion 52 (between the two chamfered surfaces 58, 59). As a result, the opening at the upper end of the rising portion 52 is covered by the mesh member 90.

[0027] As described above, mesh member 90 has a dome-shaped net structure, so that water in chamber 10 can pass through mesh member 90 and flow into second water supply pipe 31b. Similarly, water supplied from water tank 20 to first water supply pipe 31a can flow into the chamber through mesh member 90.

[0028] As described above, the water supply path 30 also serves as an overflow path, and for this reason, an overflow pipe 51 is connected to the second water supply pipe 31b. This overflow pipe 51 and water supply pipe 31b allow water in an amount exceeding the set water level in the chamber 10 to be discharged from the chamber 10 to the water tank 20. One end of the overflow pipe 51 is connected to the second water supply pipe 31b via an overflow sensor 54, and the other end is connected to the top of the water tank 20. This allows water in the chamber 10 to flow into the water tank 20 via the second water supply pipe 31b and the overflow pipe 51. In addition, the overflow sensor 54 detects the flow of water flowing from the chamber 10 toward the water tank 20.

[0029] <1-3-2. Discharge route> Next, the discharge path 40 will be described with reference to FIG. 3. FIG. 3 is a partial side view of the discharge path 40. As shown in FIG. 1, the discharge path 40 includes a drain pipe 41, an exhaust pipe 42, and a common pipe 43. The drain pipe 41 is a path through which water discharged from the chamber 10 flows. One end of the drain pipe 41 is connected to the bottom surface of the chamber 10. As a result, water in the internal space of the chamber 10 is discharged to the outside of the chamber 10 through the drain pipe 41.

[0030] A drain solenoid valve 44 is provided midway along the drain pipe 41. The drain solenoid valve 44 is switchable between an open state in which water can flow from the chamber 10 toward the water tank 20, and a closed state in which water is prohibited from flowing from the chamber 10 to the water tank 20. Here, the portion of the exhaust pipe from the chamber 10 to the drain solenoid valve 44 is referred to as a first portion 411, and the portion from the drain solenoid valve 44 to the common pipe 43 is referred to as a second portion 412.

[0031] As shown in FIG. 2 , the second portion 412 includes an extension portion 413 formed by bending and extending the drain pipe 41. The extension portion 413 is a curved portion, for example, a portion formed by winding in a spiral or volute shape. By providing the extension portion 413, the length of the second portion 412 is longer than the shortest distance L from the drain solenoid valve 44 to the common pipe 43. The length of the second portion 412 including the third portion 413 is preferably at least twice the shortest distance L from the drain solenoid valve 44 to the common pipe 43, more preferably at least five times, and particularly preferably at least ten times. The second portion 412 is formed with an inner diameter smaller than that of the first portion 411. The inner diameter of the second portion 412 may be, for example, approximately 62.5% of the inner diameter of the first portion 411. The inner diameter of second portion 412 is, for example, preferably 1.5 to 3.5 mm, and more preferably 2.0 to 3.0 mm. This reduces the pressure of the fluid flowing through second portion 412. The reduction in fluid pressure reduces the volume of the sound when water is discharged into water tank 20 through common pipe 43. In other words, second portion 412 has a noise reduction function that reduces the volume of the sound generated by sterilizer 1.

[0032] The exhaust pipe 42 is a path through which gas flows when it is exhausted from the chamber 10. One end of the exhaust pipe 42 is connected to the chamber 10 at a position above the highest water level in the internal space 101 of the chamber 10. In other words, the exhaust pipe 42 is always positioned above the water level of the water stored in the internal space 101. Furthermore, air, water vapor, or a mixture thereof within the chamber 10 is exhausted to the outside of the chamber 10 through the exhaust pipe 42.

[0033] An exhaust electromagnetic valve 45 is provided in the exhaust pipe 42. The exhaust electromagnetic valve 45 is switchable between an open state in which gas can flow from the chamber 10 toward the water tank 20 and a closed state in which gas is prohibited from flowing from the chamber 10 toward the water tank 20.

[0034] Furthermore, a pressure pipe 48 is connected midway through the exhaust pipe 42. One end of this pressure pipe 48 is connected between the chamber 10 and the exhaust solenoid valve 45, and the other end is connected to a relief valve 49 provided in the gas phase section 22 of the water tank 20. As a result, when the pressure in the chamber 10 exceeds a predetermined value, the relief valve 49 opens and the gas in the chamber 10 is released into the water tank 20. As a result, the pressure in the chamber 10 decreases, preventing the pressure in the chamber 10 from rising to an abnormal level.

[0035] One end of the common pipe 43 is connected to the drain pipe 41 and the exhaust pipe 42, and the other end is connected to the water tank 20. The common pipe 43 is a path through which both the water flowing through the drain pipe 41 and the gas flowing through the exhaust pipe 42 flow.

[0036] A condenser section 46 is disposed inside the water tank 20, and a common pipe 43 is connected to the condenser section 46. The condenser section 46 is submerged in the liquid phase section 21 inside the water tank 20. The heat of the high-temperature water and water vapor passing through the common pipe 43 is transferred to the water stored in the water tank 20 via the condenser section 46. This reduces the temperature of the fluid flowing through the common pipe 43. Furthermore, the reduction in the temperature of the fluid reduces the volume of the sound when the water is discharged into the water tank 20. In other words, the condenser section 46 has a noise reduction function that reduces the volume of the sound generated by the sterilizer 1.

[0037] Furthermore, an upwardly extending rising portion 47 is provided at the end of the condenser portion 46, and extends from the liquid phase portion 21 to the gas phase portion 22 inside the water tank 20. The upper end of the rising portion 47 is bent and extends downward. As a result, water or steam discharged from the common pipe 43 into the water tank 20 flows out toward the water stored in the water tank 20 via the condenser portion 46 and the rising portion 47.

[0038] <1-3-3. Air flow path> The air supply path 60 includes an air supply pipe 61, an air solenoid valve 62, an air pump 63, and an air filter 64. One end of the air supply pipe 61 is connected to the chamber 10, and the other end is connected to the air pump 63. As a result, air is sent from the air pump 63 into the chamber 10 through the air supply pipe 61. The air pump 63 is not particularly limited, but may be configured, for example, by a diaphragm blower. The air solenoid valve 62 is provided between the chamber 10 and the air pump 63 and opens and closes the air supply path 60. That is, the air solenoid valve 62 is switchable between an open state in which air can flow from the air pump 63 to the chamber 10, and a closed state in which air is prohibited from flowing from the air pump 63 to the chamber 10.

[0039] Furthermore, the air pump 63 is provided with an air filter 64. This purifies the air introduced into the air pump 63, and the purified air is sent into the chamber 10. As the air filter 64, for example, a HEPA filter can be used.

[0040] When air is sent into the chamber 10 through the airflow path 60, the water or water vapor in the chamber 10 is expelled to the outside of the chamber 10 by the pressure of the sent air.

[0041] Furthermore, in the air blower pipe 61, a pipe 65 is connected between the chamber 10 and the air solenoid valve 62, and a pressure gauge 66 is connected to the end of this pipe 65. This allows the pressure inside the chamber 10 to be measured by the pressure gauge 66. The measured pressure is displayed on a pressure gauge (not shown) of the pressure gauge 66 provided on the side of the housing.

[0042] <1-4. Operation panel> As shown in Figure 4, the housing of the sterilizer 1 is provided with an operation panel 7 adjacent to the opening and closing lid 11 for operating the sterilizer and making reservations. The operation panel has a display 71 on which settings and the like are displayed, and a plurality of operation buttons 72 provided below the display 71. The display 71 is composed of a liquid crystal panel or the like. The operation buttons 72 include a downward change button 721, an upward change button 722, a menu button 723, a dry button 724, a reservation button 725, a decision button 726, a first temperature button 727, a second temperature button 728, a start button 729, and a stop button 730. How to use these buttons will be described later.

[0043] <2. Electrical configuration of the sterilizer> Figure 5 is a block diagram showing the electrical configuration of the sterilizer 1. As shown in Figure 5, the sterilizer 1 is equipped with a control unit 80 that controls the operation of the sterilizer 1. The control unit 80 is made up of various types of computers such as a PLC. The control unit 80 is electrically connected to the first to third temperature sensors 16 to 18, the overflow sensor 54, and the operation panel 7. The control unit 80 receives input of detected values ​​relating to the temperature of the internal space of the chamber 10 from the first to third temperature sensors 16. The control unit 80 also receives input of detected values ​​relating to the presence or absence of a flow of water through the overflow pipe 51 from the overflow sensor 54.

[0044] The control unit 80 further includes a timer 82 that measures a predetermined time. The timer 82 is used to control the sterilization time and drying time of the object 100 to be sterilized, and is also used to control the timing of water supply into the chamber 10.

[0045] The control unit 80 outputs control signals to each device included in the sterilizer 1, such as the sterilization heater 12, drying heater, water supply solenoid valve 33, drain solenoid valve 44, exhaust solenoid valve 45, air solenoid valve 62, water supply pump 32, and air pump 63, in response to each control step of the sterilizer 1. By having each device operate appropriately in response to a control signal from the control unit 80, the sterilization process of the object 100 to be sterilized by the sterilizer 1 is carried out reliably.

[0046] <3. How to make a reservation> Next, a reservation method using the operation panel 7 will be described. This embodiment has a first mode for reserving sterilization for the current day, and a second mode for reserving sterilization for a day after the current day. In the second mode, two reservations can be made for the current day and after. In this second reservation mode, the current day and subsequent days are covered, so reservations for the same day are also possible. Therefore, three reservations can be made on the same day, including the first mode. Alternatively, in the second mode, reservations for the current day may be disabled, but reservations for the following day and later may be enabled. The reservation processing described below is performed by the control unit 80 based on the operation of the operation panel 7.

[0047] First, when the reservation button 725 is pressed, the first reservation screen shown in FIG. 6(a) is displayed on the display unit 71. This first reservation screen is a screen for making a reservation in the first mode. When the reservation button 725 is pressed from this state, the second reservation screen shown in FIG. 6(b) is displayed, and when the reservation button 725 is pressed again, the third reservation screen shown in FIG. 6(c) is displayed. The second reservation screen and the third reservation screen are screens for making a reservation in the second mode. Then, when the reservation button 725 is pressed while the third reservation screen is displayed, the display unit 71 returns to the first reservation screen of FIG. 6(a). That is, each time the reservation button 725 is pressed, the screen switches in the order of the first to third reservation screens and is displayed on the display unit 71.

[0048] The top of each reservation screen displays the reservation type (same-day reservation setting, reservation 1 setting, reservation 2 setting) and the current time. Same-day reservation setting is a reservation in the first mode, while reservation 1 setting and reservation 2 setting are reservations in the second mode. Each reservation screen also displays reservation details such as the sterilization temperature and time, drying temperature and time, and the date and time when sterilization and drying will be completed. The sterilization temperature and time, drying temperature and time, and completion time displayed on the first reservation screen shown in Figure 6(a) are the same as the reservation details made in the first mode immediately before. Meanwhile, the completion date is changed to the current day (March 1st) when the reservation is made and displayed.

[0049] The sterilization temperature and time, drying temperature and time, and completion time displayed on the second and third reservation screens shown in Figures 6(b) and 6(c) are the same as the reservation details made in the second mode immediately before on the second and third reservation screens, respectively. Meanwhile, the completion date is changed based on the reservation details made in the second mode immediately before on the second and third reservation screens, respectively. For example, assume that the current date is March 1, and the previous reservation on the second reservation screen was made on February 25, and a reservation for February 27 is made on that day. In this case, the reservation is two days after the reservation date. Therefore, the completion date displayed on the second reservation screen is set to March 3, which is two days from the current date. This is also true for the third reservation screen. For example, the completion date displayed on the third reservation screen is set to March 5, which is four days from the current date.

[0050] Pressing the start button 729 on any of the reservation screens displays a confirmation screen (not shown), and pressing the start button 729 on this confirmation screen completes the reservation setting. In this embodiment, in order to complete sterilization and drying at the completion time, the sterilizer operation is started after subtracting the sterilization time and drying time from the completion time displayed on the reservation screen.

[0051] Furthermore, by pressing the enter button 726 on any of the reservation screens, detailed reservation settings can be made. For example, by pressing the enter button 726 on the second reservation screen, a change screen is displayed as shown in FIG. 7. This change screen displays the current time (or date and time), the sterilization temperature and time, and the drying temperature and time. On this change screen, as shown in FIGS. 7(a) to 7(c), each time the enter button 726 is pressed, the display is inverted in the order of sterilization temperature, sterilization time, drying temperature, and drying time, making the screen changeable. Then, when the screen is in a changeable state, pressing the up direction change button 722 or the down direction change button 721 moves the displayed numbers up or down, changing the reservation details.

[0052] Then, as shown in FIG. 7(c), when the confirm button 726 is pressed on the screen where the drying time is changed, the screen transitions to a screen displaying the current date and time, completion date, completion time (hour), and completion time (minute), as shown in FIG. 8. This screen displays the current date and time, so the user can refer to it to determine a later reservation date and time. On this screen, too, each time the confirm button 726 is pressed, the items to be changed are highlighted in the order of completion date and completion time (hour). Then, when the confirm button is pressed while the completion time (minute) is highlighted, the screen transitions to the reservation screen shown in FIG. 6(b). When the start button 729 is pressed on this reservation screen, a confirmation screen is displayed, and when the start button 729 is pressed on this confirmation screen, the reservation setting is completed. In other words, even if the start button is pressed on the change screen, the reservation setting is not completed.

[0053] Furthermore, on the change screen, pressing the first temperature button 727 changes the sterilization and drying temperature to 135°C, and pressing the second temperature completion time (minutes) button 728 changes the sterilization and drying temperature to 121°C. The above settings on the change screen are also made when pressing the confirm button 726 on the first reservation screen or the third reservation screen.

[0054] Once the reservation setting is complete, the most recent reservation screen as shown in Fig. 9 is displayed. In the example of Fig. 9, a reservation for the current day in the first mode is displayed. The reservation screen displays the reservation completion date and time as well as the reservation setting details such as temperature and time. When the stop button 730 is pressed on this reservation screen, a reservation cancellation confirmation screen as shown in Fig. 10 is displayed, and when "Yes" is selected and the confirm button 726 is pressed, the reservation cancellation is completed.

[0055] The menu button 723 is a button for making various settings for the sterilizer, such as setting the first and second temperatures and volume, and the drying button 724 is a button used when only drying is to be performed without sterilization.

[0056] <4. Sterilizer operation> Next, the operation of the sterilizer 1 configured as described above will be described with reference to Figure 6. Figures 11 to 13 are timing charts showing the operation of each device in the sterilizer 1, and Figure 14 is a flowchart of the cooling water supply process. The timing charts in Figures 11 to 13 differ in the cooling water supply process, but the other processes are the same. Therefore, with the exception of the cooling water supply process, each process for sterilizing the object 100 to be sterilized by the sterilizer 1 will be described with reference to the timing chart in Figure 11.

[0057] As shown in Figure 11, at time T0, the power to the sterilizer 1 is turned on to start the sterilizer 1. Before starting the water supply, the operator using the sterilizer 1 opens the opening / closing lid 11 of the chamber 10, places the object 100 to be sterilized on the platform 13, and places the object 100 to be sterilized in the chamber 10. The operator may place the object 100 to be sterilized in the chamber 10 before turning the power to the sterilizer 1 on.

[0058] By switching the sterilizer 1 from power off to power on, the exhaust solenoid valve 45 turns on at time T0, as shown in Figure 11. The drain solenoid valve 44, water supply solenoid valve 33, and air solenoid valve 62 are all kept in the off (non-energized) closed state.

[0059] At this time, the gas phase portion 22 of the water tank 20 is maintained at atmospheric pressure. As described above, by opening the exhaust solenoid valve 45, the internal space of the chamber 10 and the gas phase portion 22 of the water tank 20 are connected to each other via the exhaust pipe 42 and the common pipe 43. This allows the internal space 101 of the chamber 10 to be adjusted to the same atmospheric pressure as the gas phase portion 22. By connecting the internal space 101 of the chamber 10 to the gas phase portion 22 of the water tank 20, the air pressure inside the chamber 10 and the external air pressure are kept constant. This allows the opening / closing lid 11 of the chamber 10 to be opened and closed easily.

[0060] <4-1. Cooling water supply process> The cooling water supply process is a process for lowering the temperature of the sterilization heater 12 and the chamber 10 that rose during the previous sterilization process, taking into account continuous sterilization operation. In this embodiment, three types of cooling processes are performed depending on the temperature within the chamber 10 prior to the main water supply process for sterilization. In this embodiment, different processes are performed depending on the temperature detected by the second temperature sensor 17 located at the bottom of the chamber 10. This is for the following reason: If the temperature of the sterilization heater 12 is high, even if water (main water supply) is supplied into the chamber 10 for sterilization, the water quickly evaporates, causing high pressure within the chamber 10, making it impossible to stably supply water from the water supply pipe 31 into the chamber 10. As a result, in a configuration in which the water supply pump 32 is driven for a predetermined time to supply a specified amount of water, it may not be possible to supply the specified amount of water from the water supply pipe 31 into the chamber 10. Furthermore, if the heating process is started when the temperature within the chamber 10 is high, the first temperature sensor 16 may not accurately detect that the temperature within the chamber 10 has risen to the boiling point. To resolve this situation, it is necessary to cool the sterilization heater 12 and the inside of the chamber 10 by supplying water prior to the actual water supply. Therefore, in this embodiment, the cooling water supply step is performed under three conditions: (1) the temperature inside the chamber 10 is less than 95°C, (2) the temperature inside the chamber 10 is 95°C or higher but lower than 125°C, and (3) the temperature inside the chamber 10 is 125°C or higher. The following process will be explained with reference to the flowchart in Figure 14.

[0061] <4-1-1.(1) Treatment when the temperature inside the chamber is less than 95°C> This will be described with reference to the timing chart of FIG. 11 and the flowchart of FIG. 14. First, when the temperature detected by the second temperature sensor 17 is less than 95°C (less than 95°C in step S01) and the temperature detected by the first temperature sensor 16 is less than 93°C (less than 93°C in step S02), a water supply time of 6 seconds is set (step S03), and water is supplied from the water supply pipe 31 at time T1 (step S04). At time T1, the water supply pump 32, the water supply electromagnetic valve 33, and the drain electromagnetic valve 44 are switched on. Note that if the temperature detected by the first temperature sensor 16 is 93°C or higher (93°C or higher in step S02), processing (2) described below is performed. Then, when the water supply time has elapsed (YES in step S05), the water supply is stopped at time T2. At time T2, the water supply pump 32 is switched off. The water supply solenoid valve 33, the drain solenoid valve 44, and the exhaust solenoid valve 45 remain on, and steam generated in the chamber 10 due to the water supply is discharged to the outside of the chamber 10 through the drain pipe 41, the exhaust pipe 42, and the common pipe 43. Thereafter, at time T3, the water supply solenoid valve 33 and the exhaust solenoid valve 45 are switched off, and the air solenoid valve 62 and the air pump 63 are switched on. This causes air to be pumped into the chamber 10. As a result, the pumped air pushes almost all of the water in the chamber 10 out of the chamber 10 through the drain pipe 41 and the common pipe 43. Then, after a predetermined drain time (20 seconds) has elapsed (YES in step S07), at time T4, the exhaust solenoid valve 45 is switched on, and the air pump 63 is switched off. This adjusts the pressure inside the chamber 10 to atmospheric pressure. Thereafter, at time T10, the water supply pump 32 and the water supply electromagnetic valve 33 are switched on, and the air electromagnetic valve 62 and the drain electromagnetic valve 44 are switched off, to carry out the main water supply process (step S08).

[0062] In the above process, because the temperature inside the chamber 10 is relatively low, the cooling water supply time is short at 6 seconds. Furthermore, since the cooling water is supplied only once, the process proceeds to the main water supply process early. Furthermore, because the temperature inside the chamber has already dropped, the main purpose of this process is to drain the water from the chamber. Therefore, steps S03 to S05 may be omitted and the process may proceed to the main water supply process in step S08. Furthermore, the water draining process in steps S06 to S07 may also be omitted, and the process may proceed to the main water supply process in step S08 if the temperature of the first temperature sensor 16 is below the threshold value in step S02. Note that the water supply time of 6 seconds is an example and can be changed as appropriate. Furthermore, the drainage time of 20 seconds is an example and can be changed as appropriate. The drainage time is set to the time required to drain all of the water from the chamber 10.

[0063] The threshold value of 95°C for the second temperature sensor 17 is not particularly limited, but is set to a lower temperature of 95°C because water may boil at around 97°C when the sterilizer 1 is used at high altitude. Therefore, depending on the location of use, the threshold value can be set appropriately, for example, between 90 and 99°C. This threshold value is set based on the boiling point of the liquid used for sterilization.

[0064] In the above process, in step S01, the temperature near the heater 12 is detected by the second temperature sensor 17, and a process is selected based on that temperature. Thereafter, in step S02, the temperature is detected by the first temperature sensor 16, and a process is selected based on that temperature. This is because the temperature of the internal space 101 (the region in the chamber 10 where steam accumulates, which is a region above the vicinity of the heater 12) detected by the first temperature sensor 16 differs from the temperature near the heater 12 detected by the second temperature sensor 17. That is, even if the temperature detected by the first temperature sensor 16 is below the boiling point, the temperature detected by the second temperature sensor 17 may be equal to or higher than the boiling point. Also, even if the temperature detected by the second temperature sensor 17 is below the boiling point, the temperature detected by the first temperature sensor 16 may be equal to or higher than the boiling point. The threshold value set by the first temperature sensor 16 is 93°C, which is lower than the threshold value of 95°C set by the second temperature sensor 17, in order to perform process (2) (cooling water supply process) when the temperature of the internal space 101 is near the boiling point, and to ensure that the temperature of the internal space 101 is below the boiling point before proceeding to the main water supply process.

[0065] <4-1-2.(2) Processing when the temperature inside the chamber is 95°C or higher but lower than 125°C> This will be described with reference to the timing chart of FIG. 12 and the flowchart of FIG. 14. First, when the temperature detected by the second temperature sensor 17 is equal to or higher than 95°C but lower than 125°C (95°C or higher but lower than 125°C in step S01), or equal to or higher than 93°C in step S02, a water supply time of 20 seconds is set (step S09), and water is supplied from the water supply pipe 31 at time T1 (step S10). At time T1, the water supply pump 32, the water supply solenoid valve 33, and the drain solenoid valve 44 are switched on. Then, after the water supply time has elapsed (YES in step S11), the water supply is stopped at time T2. At time T2, the water supply pump 32 is switched off. The water supply solenoid valve 33, the drain solenoid valve 44, and the exhaust solenoid valve 45 are left on, and steam generated in the chamber 10 due to the water supply is discharged to the outside of the chamber 10 through the drain pipe 41, the exhaust pipe 42, and the common pipe 43. Thereafter, at time T3, the water supply solenoid valve 33 and the exhaust solenoid valve 45 are switched off, and the air solenoid valve 62 and the air pump 63 are switched on. This causes air to be sent into the chamber 10. As a result, the sent air causes almost all of the water in the chamber 10 to be discharged via the drain pipe 41 and the common pipe 43. Then, after a predetermined drain time (40 seconds) has elapsed (YES in step S13), at time T4, the exhaust solenoid valve 45 is switched on and the air pump 63 is switched off. This causes the pressure inside the chamber 10 to be adjusted to atmospheric pressure.

[0066] If the temperature measured by the second temperature sensor is 95°C or higher (95°C or higher in step S13), it is determined that the temperature inside the chamber has not yet decreased, and the processes from step S09 to step S13 are repeated. On the other hand, if the temperature measured by the second temperature sensor 17 is less than 95°C (less than 95°C in step S14) and the temperature measured by the first temperature sensor 16 is less than 93°C (less than 93°C in step S15), the exhaust process described below is omitted, and at time T10, the water supply pump 32 and the water supply electromagnetic valve 33 are switched on, and the air solenoid valve 62 and the drain solenoid valve 44 are switched off, thereby performing the main water supply process (step S08).

[0067] On the other hand, if the temperature of first temperature sensor 16 is 93°C or higher (93°C or higher in step S15), the exhaust process (ventilation process) is repeated until the temperature of first temperature sensor 16 becomes less than 93°C. That is, by turning on air pump 63, air is sent into chamber 10 and air is exhausted from exhaust pipe 42. This reduces the temperature inside chamber 10.

[0068] In the above steps, since the temperature inside the chamber 10 is higher than in the process (1), the cooling water supply time is set to 20 seconds, which is longer than the water supply time in the process (1). In other words, the amount of water supply is set to be larger than in the process (1). Also, this process is characterized by cooling by repeatedly supplying cooling water and also performing an exhaust process. Note that the water supply time of 20 seconds is an example, and can be changed as appropriate to be longer than the water supply time in the process (1) (for example, 6 seconds). Also, the drainage time of 40 seconds is an example, and can be changed as appropriate. Since the amount of water supply is set to be larger than in the process (1), it is preferable to make the drainage time longer than in the process (1).

[0069] Furthermore, if heating of the water in chamber 10 is started when the temperature inside chamber 10 is near the boiling point during the heating and pressurizing process, first temperature sensor 16 may erroneously detect that the temperature inside chamber 10 has reached the boiling point, even though the temperature inside chamber 10 has not yet reached the boiling point, and the process may transition from the heating process to the pressurizing process. Therefore, in this embodiment, a cooling process is performed by ventilation so that the temperature inside chamber 10 detected by first temperature sensor 16 falls below the boiling point, in preparation for the next heating and pressurizing process.

[0070] <4-1-3.(3) Processing when the temperature inside the chamber is 125°C or higher> This will be described with reference to the timing chart of FIG. 13 and the flowchart of FIG. 14. First, when the temperature detected by the second temperature sensor 17 is 125°C or higher (125°C or higher in step S01), water is supplied from the water supply pipe 31 at time T1 (step S17). This water supply continues until the temperature detected by the second temperature sensor 17 falls below 125°C. This water supply is a process in which the water supply and the exhaust of steam generated in the chamber 10 due to the water supply are repeated one or more times. During this process, the drain solenoid valve 44 and the exhaust solenoid valve 45 remain on, and steam generated in the chamber 10 due to the water supply is exhausted to the outside of the chamber 10 through the drain pipe 41, the exhaust pipe 42, and the common pipe 43. Then, when the temperature detected by the second temperature sensor 17 falls below 125°C, the processes from step S14 onwards are carried out.

[0071] In the above process, since the temperature inside chamber 10 is quite high, there is no limit on the number of times the process is performed. Instead, the process is repeated until the temperature detected by second temperature sensor 17 falls below 125°C. Note that the water supply time of 3 seconds is just an example and can be changed as appropriate. Furthermore, in process (3), since a large amount of steam is generated by the water supply, the process time for discharging the steam generated in chamber 10 by the water supply to outside chamber 10 is longer than in processes (1) and (2). For example, in processes (1) and (2), the process time for discharging the steam generated in chamber 10 by the water supply to outside chamber 10 is set to 3 seconds, whereas in process (3), it is set to 12 seconds.

[0072] The threshold value of 125°C is not particularly limited, but according to tests conducted by the inventors, when the temperature is below 125°C, evaporation of the supplied water is reduced, preventing backflow of the water supplied into the chamber 10 and making it easier for the water to accumulate in the chamber 10. However, this threshold value can be set appropriately to a temperature of 100°C or higher.

[0073] <4-2.Main water supply process> 11, at time T10 when the water supply process starts, the water supply pump 32, the water supply solenoid valve 33, and the exhaust solenoid valve 42 are switched on, and the air solenoid valve 62, the air pump 63, and the drain solenoid valve 44 are switched off. This allows water to be supplied from the water storage tank 20 to the chamber 10. At this time, air within the chamber 10 is exhausted through the exhaust pipe 42, preventing the internal pressure of the chamber 10 from increasing and interfering with the supply of water to the chamber 10.

[0074] After water has been supplied for a predetermined period of time, at time T11, the water supply pump 32 and exhaust solenoid valve 42 are switched off, and the air solenoid valve 62 and air pump 63 are switched on. This pressurizes the chamber 10. At this time, because the exhaust solenoid valve 42 is closed, water in an amount exceeding the set water level in the chamber 10 is discharged out of the chamber 10 via the rising portion 52, the second water supply pipe 31b, and the overflow pipe 51. When the overflow sensor 54 changes from a state in which it detects the flow of water through the overflow pipe 51 to a state in which it does not detect the flow of water, the water supply process ends.

[0075] <4-3. Pressurization and heating process ~ Sterilization process> 11, at time T12 when the heating and pressurizing step starts, the exhaust solenoid valve 42 is switched on, and the water supply solenoid valve 33, the air solenoid valve 62, and the air pump 63 are switched off. As a result, the internal space 101 of the chamber 10 and the gas phase section 22 of the water tank 20 are connected to each other via the exhaust pipe 42 and the common pipe 43, and the internal space 101 of the chamber 10 is adjusted to atmospheric pressure.

[0076] In the heating step, sterilization heater 12 in chamber 10 is turned on to raise the water in chamber 10 to its boiling point. Once the water in chamber 10 has reached its boiling point, the process moves to the pressurization step. In the pressurization step, a substitution process is carried out in which exhaust solenoid valve 42 is repeatedly switched on and off. This heats the water, generating steam that pushes out the air in chamber 10, and the pushed-out air is exhausted to the outside of chamber 10 via exhaust pipe 42 and common pipe 43. After the substitution process is completed, exhaust solenoid valve 42 is switched off, and sterilization heater 12 is kept on until the temperature inside chamber 10 reaches the temperature required for sterilization. Once the temperature inside chamber 10 reaches the temperature required for sterilization, the process moves to the sterilization step.

[0077] In the sterilization process, water supplied to chamber 10 is heated by sterilization heater 12 to generate steam. At the same time, the object 100 to be sterilized placed on table 13 is also heated. Sterilization of object 100 to be sterilized is carried out by repeatedly turning sterilization heater 12 in chamber 10 on and off to maintain the temperature inside chamber 10 at the required temperature for sterilization (121°C or 135°C) for the required time.

[0078] When the sterilization process is completed, steam is discharged from chamber 10 to water tank 20. At this time, as shown in FIG. 11 , drain solenoid valve 44 is first turned on at time T20. This causes the water in chamber 10 to be discharged from drain pipe 41, followed by the steam. Then, at time T21, a predetermined time after time T20, exhaust solenoid valve 45 is turned on for the following reason. As described above, because extension portion 413 is provided in second portion 412 of drain pipe 41, making the path longer, and because the inner diameter of second portion 412 is smaller than that of first portion 411, it may take some time to discharge steam. Therefore, by turning on exhaust solenoid valve 45 so that steam can also be discharged from exhaust pipe 42, the time required for steam discharge is shortened. The water and steam discharged from the drain pipe 41 and the exhaust pipe 42 flows through the common pipe 43 to the condenser section 46 of the water tank 20, where it is cooled, and then is discharged into the liquid phase section 21 of the water tank 20 through the rising section 47. Once the steam discharge is completed, drying begins inside the chamber 10. At the start of the drying process, the drain solenoid valve 44 is turned off.

[0079] Furthermore, because the pressure inside chamber 10 increases during sterilization, the force of steam discharge increases during discharge, resulting in a loud noise. Therefore, in this embodiment, extension portion 413 is provided at second portion 412 of drain pipe 41, and by lengthening drain pipe 41, the force of steam discharge is reduced, thereby reducing the volume of the noise. Furthermore, by forming the inner diameter of second portion 41 of drain pipe 41 smaller than the inner diameter of first portion 411, the force of steam discharge is reduced, thereby reducing the volume of the noise.

[0080] <4-4. Drying process> In the drying step, both the sterilization heater 12 inside the chamber 10 and the drying heater 14 outside the chamber 10 are turned on. At this time, as shown in Figure 11, the exhaust solenoid valve 45 and the air solenoid valve 62 are turned on and the air pump 63 is started. This causes the air pump 63 to supply air into the chamber 10 via the air supply pipe 65.

[0081] By sending air into chamber 10, water vapor remaining in chamber 10 is exhausted to the outside of chamber 10 via exhaust pipe 42. In this way, the water vapor inside chamber 10 is replaced with low-humidity air, thereby drying the object 100 to be sterilized inside chamber 10.

[0082] One end of the air supply pipe 65 is connected to a position above the chamber 10. Meanwhile, one end of the exhaust pipe 42 is connected to a position above the highest water level in the internal space 101 of the chamber 10, and away from the one end of the air supply pipe 65 below the chamber 10. This allows the air sent into the chamber 10 to circulate easily within the chamber 10, and enables the objects to be sterilized 100 inside the chamber 10 to be dried efficiently.

[0083] Once the set drying time has elapsed, air solenoid valve 62 is closed and both heaters 12, 14 and air pump 63 are stopped, completing all processes for sterilizing the object 100. In this state, sterilization heater 12 and drying heater 14 are off, and only exhaust solenoid valve 45, which connects chamber 10 to gas phase 22 of water tank 20, is open, which is the same state as time T0 shown in Figure 11. In this state, the operator can safely open opening / closing lid 11 and remove the sterilized object 100 from chamber 10.

[0084] <5. Features> In this embodiment, the following effects can be obtained. (1) In the above-described sterilization process, the pressure inside chamber 10 becomes high, and therefore when drain solenoid valve 44 is turned on to drain steam, the steam is discharged with great force (high pressure), generating a loud noise. Therefore, in this embodiment, extension portion 413 is provided in second portion 412 of drain pipe 41. By increasing the length of second portion 412 with extension portion 413, the length of second portion 412 is formed to be longer than the shortest distance between solenoid drain valve 44 and common pipe 43. This reduces the force of steam passing through second portion 412. As a result, the volume of the noise can be reduced.

[0085] (2) Because the second portion 412 of the drain pipe 41 is made of a flexible resin material such as fluororesin, the extension portion 413 can be easily formed by bending the drain pipe 41 as described above. Therefore, the extension portion 413 of the desired length can be easily formed.

[0086] (3) Reducing the inner diameter of the exhaust pipe 41 also contributes to reducing the momentum of steam passing through the drain pipe 41. For this reason, in this embodiment, the inner diameter of the second portion 412 of the exhaust pipe 41 is made smaller than that of the first portion 411. This also reduces the momentum of steam passing through the second portion 412, thereby reducing the volume of the noise.

[0087] (4) It may take time to exhaust the steam by reducing the force of the steam passing through the second portion 412. Therefore, in this embodiment, when the drain solenoid valve is turned on to exhaust the steam, the exhaust solenoid valve 45 is turned on to also exhaust the steam from the drain pipe 42. This allows steam to be exhausted from both the drain pipe and the exhaust pipe, thereby shortening the time required to exhaust the steam.

[0088] <6. Variations> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the following modifications are possible. Furthermore, the gist of the following modifications can be appropriately combined with each other and can also be combined with the above embodiment.

[0089] (1) The structure of the steam sterilizer shown in the above embodiment is an example and can be modified in various ways. Therefore, the operation processing performed by the control unit 80 can also be modified as appropriate.

[0090] (2) In the above embodiment, the second portion 412 is formed from a flexible material, but this is not limiting. That is, the entire second portion 412 does not have to be formed from a flexible material; for example, only a portion, such as the portion where the extension portion 413 is formed, may be formed from a flexible material. Alternatively, as long as the length of the second portion 412 can be formed to be longer than the shortest distance between the electromagnetic drain valve 44 and the common pipe 43, the material of the second portion is not particularly limited, and may be a metal pipe member.

[0091] (3) In the above embodiment, the extension portion 413 has been illustrated as having a curved shape such as a spiral or a volute, but the configuration of the extension portion 413 is not limited to this. That is, in order to make the extension portion 413 compact, it may have various shapes, such as a wave shape or a square wave shape. Furthermore, if the space for the extension portion can be secured, the second portion 412 may simply be made longer without bending the extension portion 413.

[0092] (4) In the above embodiment, the inner diameter of the second portion 412 of the drain pipe 41 is smaller than that of the first portion 411, but the portion where the inner diameter is made smaller is not particularly limited, and the inner diameter of the entire drain pipe 41 can also be made smaller, for example, to 2.0 to 3.0 mm. Also, the inner diameter of at least a portion of the drain pipe 41 may be made larger than 2.0 to 3.0 mm, and the volume of the sound may be reduced mainly by forming the extension portion 413 alone.

[0093] (5) In the above embodiment, the inner diameter of the second portion 412 of the exhaust pipe 41 is smaller than that of the first portion 411. The inner diameter of the second portion 412 may be made smaller than that of the first portion 411 by pressing at least a portion of the second portion 412 with a solenoid valve or the like to reduce the inner diameter.

[0094] (6) The above-described solenoid valves 44, 45, and 62 may be any valve other than solenoid valves as long as they can be opened and closed by the control unit 80, and may be appropriately changed to valves other than solenoid valves. [Example]

[0095] In the above-mentioned steam sterilizer, the second section of the drain pipe was formed as follows, and the sound of steam discharge was measured. The measurement conditions are as follows. Second part material: Fluorine resin - Inner diameter of second section: 2.5mm ·Sterilization temperature: 135℃ Shortest distance between drain solenoid valve and common pipe: 77mm A microphone was placed 1 m horizontally away from the opening and closing door of the steam sterilizer (bystander position), and the sound level was measured based on JIS Z 8737-2 (2000).

[0096] The results are as follows: The test with the second part at 770 mm was performed three times, and the test with the second part at 77 mm was performed only once. [Table 1]

[0097] According to Table 1, it was found that the longer the length of the second portion, the more the steam exhaust noise was reduced. [Explanation of symbols]

[0098] 1: Steam sterilizer 10: Chamber 20: Water tank (liquid storage tank) 41: Drain pipe 411: Part 1 412:Second part 413: Extension site 42: Exhaust pipe 43: Common pipe 44: Drain solenoid valve (first opening / closing valve) 45: Exhaust solenoid valve (second opening / closing valve)

Claims

1. a chamber capable of accommodating an object to be sterilized; a heater for heating the liquid supplied into the chamber; A liquid storage tank; a drain for draining liquid from the chamber; a first on-off valve provided in the drainage pipe; an exhaust pipe for discharging gas from the chamber; a second on-off valve provided in the exhaust pipe; a common pipe for sending the liquid discharged from the drain pipe and the gas discharged from the exhaust pipe to the liquid storage tank; A control unit; Equipped with the control unit is configured to open the first on-off valve to start discharging the liquid from the drain pipe after sterilizing the object to be sterilized, and then open the second on-off valve to start discharging the gas from the exhaust pipe, the drain pipe has a first portion connecting the chamber and the first on-off valve, and a second portion connecting the first on-off valve and the common pipe; The second portion is formed to be longer than the shortest distance between the first on-off valve and the common pipe. Steam sterilizer.

2. The length of the second portion is at least twice the shortest distance. The steam sterilizer of claim 1.

3. At least a portion of the second portion is formed from a flexible material.

3. The steam sterilizer according to claim 1 or 2.

4. At least a portion of the second section is curved.

3. The steam sterilizer according to claim 1 or 2.

5. The inner diameter of the second portion is smaller than the inner diameter of the first portion.

3. The steam sterilizer according to claim 1 or 2.

6. The inner diameter of the second portion is 2.0 to 3.0 mm.

3. The steam sterilizer according to claim 1 or 2.

7. the control unit is configured to open the second on-off valve to start discharging the gas from the exhaust pipe while the liquid is being discharged from the drain pipe.

3. The steam sterilizer according to claim 1 or 2.

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