JP2024057769A - Steam sterilizer - Google Patents

Abstract

To provide a steam sterilizer capable of performing stable steam sterilization treatment.SOLUTION: A steam sterilizer S includes: a can body 3 having a placing part 4 inside for placing an object to be sterilized; a water storage part 5 provided below the placing part 4 inside the can body 3; a water feed mechanism Pa for feeding water to the water storage part 5; a heater 7 disposed in the water storage part 5; a sensor 20 standing in the water storage part 5 for detecting a water level of the water storage part 5; and a control part 19 for controlling water feed stoppage by the water feed mechanism Pa on the basis of a detection result of the sensor 20, where the sensor 20 includes a base part 20a fixed to the water storage part 5, a laterally extending part 20b extending in a direction along a water surface above the water surface of the water stored in the water storage part 5 from the base part 20a, and a detection part 20c for detecting a water surface by being suspended from the laterally extending part 20b at a position away from the base part 20a and contacting the water surface.SELECTED DRAWING: Figure 2

Description

The present invention relates to a steam sterilizer that uses steam to sterilize items held inside a can body.

Conventional techniques related to such steam sterilizers include, for example, those shown in the following Patent Document 1 (see paragraphs [0006], [0008], [0026] and Figure 4 of the specification).

The steam sterilizer of Patent Document 1 comprises a can body 2 capable of containing objects to be sterilized, a water storage tank 39 for supplying water to the inside of the can body 2, a sterilization heater 12 provided in the can body 2, a water supply pipe 27 connecting the can body 2 and the water storage tank 39, a water supply solenoid valve 30 for opening and closing the flow path of the water supply pipe 27, an air vent pipe 21 connected to the can body 2, and an air pump 23 connected to the air vent pipe 21. With this configuration, water is stored inside the can body 2, the water is heated to steam by the sterilization heater 12, and the objects to be sterilized held inside the can body 2 are steam sterilized.

After the steam sterilization process is completed, the steam inside the can body 2 is discharged, but any remaining moisture is vaporized and discharged while the inside of the can body 2 is further heated by the drying heater 13 to ensure that the items to be sterilized are completely dried.

In this steam sterilizer, the amount of water supplied to the can body 2 is determined so that no moisture remains on the surface of the object to be sterilized when the sterilization and drying processes are completed, and the temperature adjustment process of the sterilization heater 12 and the opening and closing timing of the water supply solenoid valve 30 are specified in a time schedule. With this configuration, objects to be sterilized can be efficiently steam sterilized compared to conventional steam sterilizers.

JP 2017-209188 A

In the above conventional steam sterilizer, a water level electrode 14 is used to set the amount of water stored in the can body 2. The water level electrode 14 protrudes from the bottom surface of the can body 2, and about two-thirds of the area from the bottom is covered with an insulating material, and an electrode that conducts electricity when it comes into contact with water is located above it. When the water level inside the can body 2 rises and exceeds the insulating part of the water level electrode 14, an electrical signal is generated, which indicates that the specified water level has been reached.

However, when the water level rises along the water level electrode 14, the surface tension of the water acts differently when the surface of the water level electrode 14 is dry and when it is wet. For example, when the surface of the water level electrode 14 is dry, the contact position between the water level electrode 14 and the water surface is lower than the actual height of the water surface due to the surface tension acting between the surface and the water. This results in a larger amount of water being supplied to the can body, resulting in insufficient drying of the objects to be sterilized.

On the other hand, when the surface of the water level electrode 14 is wet, the wettability of the water on the surface causes the contact position between the water level electrode 14 and the water surface to be slightly higher than the actual water surface height. However, since the water surface is only elevated near the surface, in this case the amount of water supplied to the can body 2 is approximately accurate.

As described above, the conventional technology had the problem that the amount of water supplied to the can body was not always accurate, making it difficult to maintain uniformity in the drying process during steam sterilization. Therefore, there has been a demand for a steam sterilizer that can perform stable steam sterilization.

The steam sterilizer according to the present invention has the following features:
A can body having an internal placement portion on which the object to be sterilized is placed;
A water storage section provided inside the tank body and below the placement section;
a water supply mechanism for supplying water to the water storage section;
A heater installed in the water storage section;
A sensor that is installed in the water storage portion and detects a water level in the water storage portion;
a control unit that controls the water supply mechanism to stop supplying water based on a detection result of the sensor.
A base attached to the water storage portion and surrounded by an insulator;
A horizontal section extending from the base section in a direction along the water surface above the water surface of the water stored in the water storage section;
It is characterized in that it is equipped with a detection unit that hangs down from the cross section at a position away from the base and detects the water surface by abutting against the water surface.

(effect)
The steam sterilizer of this configuration is equipped with a sensor that contacts the water surface of the water stored in the water storage section. The sensor includes a base that is attached to the water storage section, a horizontal section that extends from the base in a direction along the water surface and has an area spaced from the water surface, and a detection section that hangs down from the horizontal section and contacts the water surface.

In this configuration, at least a portion of the base is in contact with the water in the water storage section, and surface tension acts on the surface of the base at the boundary with the water surface. This creates a difference between the actual water surface height and the height of the highest point of the water in contact with the base.

Therefore, by using a sensor of this configuration, the position of the water surface where the detection unit contacts is set to a position along the water surface that is spaced from the base. The extension direction of the cross section at this time includes a direction parallel to the water surface and a direction at a specified angle to the water surface. This eliminates the effects of surface tension, and makes it possible to always accurately measure the position of the water surface regardless of differences in the cleanliness of the surface of the base.

As a result, unlike conventional sensors, there is no need to perform calculations to eliminate the effects of surface tension, and there is no need to adjust the cleanliness of the base, making it extremely easy and accurate to set the liquid level in the reservoir.

In the steam sterilizer of the present invention, it is advantageous if the periphery of the base is covered with an insulator.

(effect)
By covering the periphery of the base with an insulator, there is no risk of false detection signals being generated due to contact between the base and the stored water. In addition, for example, the base and the detection unit can be made of the same material, which not only simplifies the sensor configuration but also expands the range of possible configurations for the base.

In the steam sterilizer of the present invention, it is more convenient if the cross section is covered with an insulator.

(effect)
The horizontal section extends from the base along the water surface, so there is little chance that it will come into contact with the stored water. However, by covering the horizontal section with an insulator, it is possible to reliably prevent a detection signal from being erroneously generated even if water droplets are attached to the horizontal section. This makes it possible to obtain a more reliable steam sterilizer.

The steam sterilizer according to the present invention can be configured so that multiple sets of the cross members and the detectors extend in different directions from the base.

(effect)
By providing multiple sets of horizontal units and detectors as in this configuration, even if there is an error in the detection value of each detector, the error can be averaged to approach the correct water level. For example, the accuracy of measuring the water level is improved when the steam sterilizer is installed in an inclined position.

In addition, even if one of the multiple detection units is broken, the water surface height can be detected using the detection data obtained from at least one of them. Conversely, if all of the detection units are not functioning, an error determination can be issued quickly, allowing high measurement accuracy to be maintained.

In the steam sterilizer according to the present invention, it is advantageous if a male thread is formed at the lower end of the base.

(effect)
If a male screw portion is formed at the lower end of the base, the sensor can be easily attached to the bottom of the water storage portion. For example, by configuring the male screw portion to penetrate the bottom of the can body, it can be fixed with a nut or the like on the outside of the can body. With this configuration, the insertion depth of the male screw portion into the can body can be changed, making it easy to set the height of the sensor in the water storage portion.

In the steam sterilizer according to the present invention, it is preferable that the base is columnar, the cross section is disk-shaped and coaxial with the base and is attached to the end of the base, and the detection section is a cylindrical wall section that protrudes from the underside of the cross section.

(effect)
If the detection part is formed to extend in only one direction from the base, the water level will be detected earlier if the steam sterilizer is, for example, inclined low in the direction in which the horizontal part extends, and conversely, if it is inclined low in the opposite direction to the extension of the horizontal part, the water level will be detected later, resulting in a large difference between the two.

However, by providing the detection units around the entire circumference of the base as in this configuration, even if the steam sterilizer is installed at an angle, the detection unit at the lowest position will react to the water surface. This reduces the error with the water surface detection position when the steam sterilizer is installed in the normal position, making it easier for the steam sterilizer to perform a stable drying function.

In the steam sterilizer according to the present invention, it is advantageous if a height adjustment screw portion is formed between the upper end of the base and the cross section.

(effect)
With this configuration, for example, the horizontal frame can be screwed to the base so that the height position can be freely changed, making it extremely easy to adjust the height of the horizontal frame. In particular, with this configuration, the height adjustment can be easily performed even after the sensor is installed inside the tank body. Therefore, the height position of the horizontal frame can be quickly and accurately set to match the water level of the water supplied to the water storage section.

FIG. 1 is a perspective view showing the appearance of a steam sterilizer according to an embodiment of the present invention. FIG. 1 is an explanatory diagram showing the overall configuration of a steam sterilizer according to an embodiment of the present invention. FIG. 1 is an explanatory diagram showing the configuration of a sensor and a water surface detection mode in the present embodiment. A time chart showing the operation of the steam sterilizer of this embodiment. A flowchart showing the water supply process of the steam sterilizer of this embodiment. FIG. 13 is an explanatory diagram showing a sensor according to another embodiment. FIG. 13 is an exploded perspective view showing a sensor according to another embodiment.

[Embodiment]
(overview)
An embodiment of a steam sterilizer S according to the present invention is shown in Figures 1 to 5. This steam sterilizer S has a cylindrical can body 3 inside an apparatus main body 2 equipped with a door 1 that swings open and closed, and sterilizes objects to be sterilized, such as medical instruments and medicine bottles, placed inside the can body 3 with high-temperature steam. Inside the can body 3, for example, a tray-shaped member is provided as a placement portion 4 for the objects to be sterilized, and below the placement portion 4, a water storage portion 5 for storing water is provided. The water storage portion 5 utilizes a part of the inner wall of the can body 3.

Water can be supplied and discharged between the water storage section 5 and a water storage tank 6 located above the exterior of the can body 3, and the water stored in the water storage section 5 is vaporized by a sterilization heater 7. The can body 3 is also equipped with a drying heater 8 located on the exterior of the can body 3 to heat the can body 3 and dry the inside, and a pressure switch 9 that constantly detects the pressure of the can body 3. The sterilization heater 7 and drying heater 8 are temperature-controlled using an overheat detection thermistor 10 and a temperature control thermistor 11, which are provided separately for each.

A communication pipe 12 is connected to the side of the can body 3, and an air solenoid valve 13, an air pump 14, and an air filter 15 are connected to the communication pipe 12. These adjust the internal pressure of the can body 3.

A supply and drain pipe 16 for water supply and drainage is connected to the bottom of the tank body 3. The supply and drain pipe 16 branches into a water supply pipe 16a and a drain pipe 16b, which are connected to the water storage tank 6 via a water supply solenoid valve SV3 and a drain solenoid valve SV4, respectively. In particular, the end of the drain pipe 16b is inserted inside the water storage tank 6 and a silencer 18 is attached. This makes it possible to eliminate noise during drainage.

Of these components, the communicating pipe 12, air solenoid valve 13, air pump 14, air filter 15, supply and drain pipe 16, water supply pipe 16a, drain pipe 16b, water supply solenoid valve SV3, and drain solenoid valve SV4, which function to supply and drain water to and from the can body 3, are collectively referred to as the water supply and drainage mechanism P. Note that the communicating pipe 12, air solenoid valve 13, air pump 14, air filter 15, supply and drain pipe 16, water supply pipe 16a, and water supply solenoid valve SV3 may be referred to as the water supply mechanism Pa.

The steam sterilizer S, via the control unit 19, sequentially performs preheating/water supply processing, heating processing, sterilization processing, steam exhaust processing, and drying processing from a standby state.

(1) Preheating and Water Supply Process As shown in the time chart of FIG. 4, in the preheating and water supply process, the items to be sterilized are placed inside the can body 3, and the drain solenoid valve SV4 is opened and the air pump 14 is driven for a predetermined time (here, 30 seconds) to perform the drainage process.

Next, electricity is applied to the sterilization heater 7 and the drying heater 8, and each is set to 70°C. When the sterilization heater 7 and the drying heater 8 reach 70°C, electricity to each heater is stopped, and the water supply solenoid valve SV3 is opened to supply water to the can body 3. This water supply is continued until the water level reaches a predetermined level as detected by the sensor 20.

(2) Heating Treatment Electricity is applied to the sterilization heater 7 to heat the water in the water storage section 5 and generate steam. At this time, air inside the can body 3 is discharged through the second pipe 21. After the internal temperature of the can body 3 reaches 95°C, electricity is continued to be applied to the sterilization heater 7 until a predetermined time (e.g., 3 minutes) has elapsed.

Next, if the internal temperature of the can body 3 exceeds 102°C, or if the difference between the temperature detected by the overheat detection thermistor 10 and the temperature detected by the temperature control thermistor 11 becomes 1°C or less, it is determined that the inside of the can body 3 is filled with steam, and the steam exhaust solenoid valve SV1 of the second pipe 21 is closed.

(3) Sterilization process Power supply to the sterilization heater 7 is controlled so as to maintain the sterilization temperature based on the temperature detected by the overheat detection thermistor 10. As a result, the object to be sterilized contained in the can body 3 is sterilized by high-temperature steam.

(4) Waste steam treatment First, the steam discharge solenoid valve SV1 provided on the second pipe 21 is opened. As a result, the steam in the can body 3 is depressurized in the steam discharge tank 22 and then discharged into the water storage tank 6. Noise is generated during this process, but this is silenced by the silencer 18 provided inside the water storage tank 6. When a predetermined time (e.g., 80 seconds) has elapsed since the start of the steam discharge process, the wastewater treatment is started. During the steam discharge process, the sterilization heater 7 is maintained at 170°C, and the drying heater 8 is maintained at 130°C.

The drain solenoid valve SV4 is opened following the steam exhaust solenoid valve SV1. This allows any water remaining in the can body 3 to be drained into the water storage tank 6. In this way, by first exhausting the high-pressure steam in the steam exhaust process and then draining the water, the steam does not condense and wet the items to be sterilized.

After a predetermined time (e.g., 10 seconds) has elapsed since the drain solenoid valve SV4 was opened, the steam discharge solenoid valve SV1 is temporarily closed. This prevents the steam pressure inside the boiler body 3 from dropping too much, making it impossible to drain the remaining water. A silencer 18 is also provided at the tip of the drain pipe 16b to eliminate noise during discharge.

When a predetermined time (e.g., 10 seconds) has elapsed since the steam exhaust solenoid valve SV1 was closed, it is assumed that all the remaining water in the boiler body 3 has been drained, and the steam exhaust solenoid valve SV1 is opened and the drain solenoid valve SV4 is closed. At this time, the exhaust solenoid valve SV2 is also opened. This causes the steam in the steam exhaust tank 22 to be returned to the water storage tank 6.

Then, after a predetermined time (e.g., 80 seconds) has elapsed since the exhaust solenoid valve SV2 was opened, the air pump 14 starts to operate, and the drain solenoid valve SV4 is temporarily opened to discharge the water remaining inside the can body 3 by the internal pressure.

(5) Drying Treatment After the steam discharge treatment, the air pump 14 is driven while continuing to energize the sterilization heater 7 and the drying heater 8, thereby drying the inside of the can body 3.

(Sensor)
3 shows the sensor 20 used in the steam sterilizer S of this embodiment. The sensor 20 comprises a rod-shaped base 20a made of a conductive material so as to function as a part of the electrode F, and a cross section 20b attached to the tip of the base 20a. A detection section 20c that comes into contact with the water stored in the water storage section 5 is provided at the tip of the cross section 20b.

A male thread 20d is formed at the lower end of the base 20a, and the sensor 20 is attached in a vertical position to the bottom of the water storage section 5 by this male thread 20d. The male thread 20d penetrates the bottom of the can body 3 and is fixed by a nut 20i on the outside of the can body 3. At that time, annular seal rings 20j are attached between the insulator 20e and the can body 3, and between the can body 3 and the nut 20i to prevent water leakage. The height of the sensor 20 in the water storage section 5 can be easily adjusted by changing the insertion depth of the male thread 20d into the can body 3.

An insulator 20e made of a cylindrical member is placed around the base 20a. The insulator 20e is made of, for example, silicone rubber. The insulator 20e prevents water from coming into contact with the base 20a, and is configured so that no detection signal is generated. Furthermore, if the base 20a and the detection unit 20c are made of the same material, the configuration of the sensor 20 is simplified and the range of configurations that can be taken for the base 20a can be expanded.

As shown in FIG. 3, a female thread 20f is formed at the end of the base 20a, and a hole 20g is formed in the cross section 20b into which the end of the base 20a is inserted. A fixing bolt 20h is screwed into the female thread 20f, and the cross section 20b is fixed to the end of the base 20a. The base 20a and the cross section 20b are made of, for example, stainless steel.

The sensor 20 of this embodiment can be used in multiple types of steam sterilizers S with different water surface heights in the water storage section 5, making it easier to improve, for example, conventional steam sterilizers S, and improving the reliability of the steam sterilizers S.

The horizontal section 20b is, in principle, held at a position higher than the water surface in the water storage section 5. The outer periphery of the horizontal section 20b is the detection section 20c that hangs down, and the bottom surface of this detection section 20c becomes the detection surface 20k with respect to the water surface. To achieve this, it is preferable to paint the areas of the horizontal section 20b and the detection section 20c excluding the detection surface 20k with, for example, an insulating paint, or to attach an insulating material such as silicone rubber. This prevents the water surface detection signal from being erroneously issued even if water droplets are attached to the horizontal section 20b, and makes it possible to obtain a more reliable steam sterilizer S.

The reason for providing the drooping detection unit 20c in this manner is to accurately detect the water level of the water supplied to the water storage unit 5. With this configuration, the detection unit 20c is set at a position separated along the water surface via the cross section 20b from the base 20a that stands upright in the water of the water storage unit 5. The dotted line in Figure 3(b) indicates, for example, a state in which the surface of the insulator 20e is clean and the boundary between the water surface and the insulator 20e is raised above the water surface. On the other hand, the dashed and dotted line indicates, for example, a state in which the surface of the insulator 20e is dirty and the boundary between the water surface and the insulator 20e is lowered below the water surface.

In this way, the detection unit 20c comes into contact with the water surface in an area where the surface tension of the water is effective against the surface of the base 20a, that is, at a position away from the area near the surface of the base 20a. Therefore, the detection surface 20k can detect the correct water surface height regardless of differences in the cleanliness of the surface of the base 20a.

With this configuration, unlike conventional sensors 20, there is no need to perform calculations to eliminate the effects of surface tension, and there is no need to adjust the cleanliness of the base 20a, making it possible to set the liquid level in the water storage section 5 extremely easily and accurately.

In particular, because the cross section 20b is disk-shaped and the entire periphery extends along the water surface from the base 20a as the center, even if the steam sterilizer S is installed at an angle, the detection surface 20k at the lowest position of the detection section 20c reacts to the water surface. This reduces the error with the water surface detection position when the steam sterilizer S is installed in the normal position, making it easier for the steam sterilizer S to perform a stable drying function.

(Water supply treatment work flow)
5 shows a flow chart of the water supply process using the sensor 20. Prior to new water supply to the water storage section 5, a pumping steaming process is carried out for 15 seconds (#1) to remove moisture from inside the can body 3. Then, it is confirmed whether 3 minutes have passed since the end of the pumping steaming process or whether the temperature of the sterilization heater 7 has dropped below 170°C (#2).

Checking the elapsed time of three minutes prevents the sensor 20 from making a false detection when water supply to the water storage section 5 has not yet started. For example, when the steam sterilizer S is operated continuously, if the next operation is started while the sterilization heater 7 is still hot, the supplied water will evaporate rapidly. If the steam generated by this comes into contact with the detection section 20c of the sensor 20, a detection signal may be generated. Therefore, three minutes is set from the start of the water supply process to ensure that the sterilization heater 7 has time to cool down.

Following completion of the confirmation in step #2, it is checked whether the circuit of the sensor 20 is in the ON state (#3). The state of the sensor 20 is checked here in order to check for any malfunctions caused by the previous steam sterilization process. For example, there are exceptional cases where water remains, such as when the drying process was not performed and water remains, or when the user pours water directly into the can body 3 rather than from the water storage tank 6. If it is already in the ON state, proceed to the end of the flowchart and perform the pump steam discharge process again.

On the other hand, if the circuit of the sensor 20 is not yet ON, the door 1 of the can body 3 is opened a predetermined amount (#4) to exhaust the air inside the can body 3. If moisture remains inside and the temperature of the sterilization heater 7 is still high, the internal pressure of the can body 3 may rise. In that case, this is to prevent inconvenience such as steam leaking out during the subsequent sterilization process, etc.

Next, with door 1 open, water is supplied to water storage section 5 (#5). Following this, the air bleed process of can body 3 is checked. It is checked whether 5 minutes have passed since the start of pump steaming process and whether the air has been bled from can body 3 (#6). If 5 minutes have passed and the air has not been bled yet, the air bleed operation (#7) is performed. This sets the interior of can body 3 to a specified pressure. After this, it is checked whether 10 minutes have passed since the start of pump steaming process (#8).

In addition, in (#6), if both of the following conditions are not met: 5 minutes have passed since the start of the pump-drain process and air has not been removed; in other words, if the time that has passed since the start of the pump-drain process is a short period of time (less than 5 minutes) or air removal has been completed, the process is considered to be in the normal water supply process and the elapsed time will continue to be counted.

In step #8, it is checked whether 10 minutes have passed since the start of the pump steaming process. This 10-minute time count takes into account the normal time it takes for the sensor 20 to detect the water surface. Therefore, if 10 minutes have not passed in the processing step (#8), it is checked whether the sensor 20 has turned ON (#9). If the sensor 20 has turned ON, the water supply is stopped (#10).

On the other hand, if 10 minutes have passed without the sensor 20 turning ON in step (#8), it is assumed that some kind of error has occurred and the water supply is stopped (#13). When the water supply is stopped, it is determined that there is a water supply timeout error (#14) and a two-minute drain operation is performed (#15). At this time, the user is notified of the error state, for example by sound or LCD display. The user performs the error cancellation procedure by checking the condition of the can body 3, etc.

If the sensor 20 is not ON in the processing step (#9), it is checked whether 90 seconds have passed since the start of water supply (#16), and if 90 seconds have not passed, the water supply process continues. On the other hand, if 90 seconds have already passed, it is checked whether the door 1 of the can body 3 is open (#17). If the door 1 is not open, the water supply process continues, and if the door 1 is open, it is closed (#18) to prevent water leakage, and then the water supply process continues.

When the water supply is stopped in step (#10), it is checked whether the time since the start of the water supply is 30 seconds or more (#11). Considering the volume of the water storage section 5, a normal water supply operation requires 30 seconds. Therefore, the reliability of the water supply operation is also checked by the elapsed time. If the elapsed time is 30 seconds or more, it is checked whether the lid of the can body 3 is in the closed position (#12). Since the door 1 was opened in step (#4), if this is the first time step (#12) is reached, the determination here is NO. In the following step (#23), the door 1 is closed and the water supply operation is completed. On the other hand, if the door 1 has already been closed in the above-mentioned step (#18), etc., the determination is YES in step (#12) and the water supply operation is completed.

If 30 seconds or more have not passed since the pump steam discharge process in step (#11), it is checked whether the water supply process is being retried (#19). In other words, if the water supply is stopped (#10) in less than 30 seconds (#11) after the water supply process has started, the water storage section 5 is not usually filled in such a short time, so the drainage process is performed first. Specifically, when step (#19) is reached for the first time, the water supply process is not being retried, so the answer is NO, the door 1 is closed (#21), and the water is drained for 30 seconds (#22).

On the other hand, if the process has already returned to step (#5) at least once when step (#19) is reached, the water supply process is considered to have been retried in step (#19), door 1 is closed, and a water supply timeout error is determined to have occurred in step (#14). In other words, if the sensor 20 detects the water surface in a short time even after drainage process is performed in step (#22) and the water supply process is started from the beginning, it is determined that there is an abnormality in the sensor 20, and error processing is performed.

[Another embodiment]
In another embodiment of the sensor 20, as shown in Fig. 6, the base 20a to the detection portion 20c may be formed of an integrated conductive member, and the entire sensor 20 may be bent, for example, into a J shape. A male thread 20d is formed at the end of the linear portion of the base 20a, and the detection portion 20c is formed at the tip of the bent side. The area other than the detection portion 20c is covered with an insulator 20e.

With this configuration, the structure of the sensor 20 is extremely simple, yet the detection unit 20c can come into contact with the water surface where there is no effect of surface tension, resulting in a sensor 20 with high detection accuracy.

Although not shown in the figures, two or more such sensors 20 can be installed in a set, and the extension directions of the respective cross sections 20b can be set so that the angles between adjacent cross sections 20b in the horizontal plane are equal. In this case, multiple sets of cross sections 20b and detection sections 20c can be configured to extend from one base 20a.

By providing multiple sets of sensors 20 as in this configuration, even if there is an error in the detection value of each detection unit 20c, the error is averaged and a more accurate water level can be obtained. For example, the accuracy of measuring the water level is improved when the steam sterilizer S is installed in an inclined position.

In addition, even if one of the multiple detection units 20c is broken, the water surface height can be detected using the detection data obtained from at least one of them. Conversely, if all of the detection units 20c are not functioning, an error determination can be issued quickly, allowing high measurement accuracy to be maintained.

The steam sterilizer S of this embodiment can supply an appropriate amount of water to the water storage section 5 during the water supply process, and in particular, the objects to be sterilized are not left in a wet state after the sterilization process, and the steam sterilization process can be performed reliably.

Figure 7 shows another sensor. In this example, the height of the cross section 20b relative to the base 20a can be adjusted. Specifically, the upper end of the base 20a is formed with a male screw 20m as a height adjustment screw, and the cross section 20b is formed with a female screw 20n as a height adjustment screw. This allows the cross section 20b to be screwed to the base 20a so that the height position can be freely changed. After determining the height position of the cross section 20b relative to the base 20a, the fixing nut 20p is screwed onto the male screw 20m and tightened in a state where it is pressed against the cross section 20b, thereby stably fixing the cross section 20b.

This configuration makes it extremely easy to adjust the height of the horizontal section 20b. The height of the horizontal section 20b can also be adjusted by adjusting the screw depth of the male threaded section 20d formed at the lower end of the base section 20a. In that case, however, the nut 20i must be fastened from the back side of the water storage section 5, making the height adjustment work complicated. In this respect, this other embodiment makes it possible to adjust the height inside the can body 3. Therefore, the height position of the horizontal section 20b can be easily and accurately set to match the water level of the water supplied to the water storage section 5.

Before step #2 in the flowchart of FIG. 5, the state of the sensor 20 may be checked within a predetermined short time from the start of water supply. For example, a time such as 5 seconds from the start of water supply is set, and if the sensor 20 is ON at that time, a false detection has occurred. In that case, the drain process is performed once and the water supply process is performed again. If the sensor 20 still falsely detects even after retrying the water supply process in this way, there is a high possibility that the sensor 20 is broken. Therefore, if the sensor 20 turns ON within a short time, it is better to display an error to prevent subsequent empty-burning, etc.

Failed detection by the sensor 20 may also occur due to dirt on the sensor 20. In such a case, in order to promptly clean the sensor 20, for example, the presence or absence of dirt is checked using the following process. If the sensor 20 is in the ON state at the start of operation, air pressure is applied to the can body 3 to drain the water inside. This checks whether the sensor 20 is in the OFF state. If the ON state is maintained, an error message is displayed to prompt cleaning. This allows problems with the steam sterilizer S to be improved early.

The steam sterilizer according to the present invention can be widely applied to devices that use a sensor that moves the water level up and down along the side as a detection unit for measuring the water level.

3 Can body 4 Placement section 5 Water storage section 7 Heater (sterilization heater)
19 Control unit 20 Sensor 20a Base 20b Horizontal frame 20c Detection unit 20d Male screw portion 20e Insulator Pa Water supply mechanism S Steam sterilizer 20m Height adjustment male screw portion (height adjustment screw portion)
20n Adjustable female screw part (adjustable screw part)

Claims (7)

A can body having an internal placement portion on which the object to be sterilized is placed;
A water storage section provided inside the tank body and below the placement section;
a water supply mechanism for supplying water to the water storage section;
A heater installed in the water storage section;
A sensor that is installed in the water storage portion and detects a water level in the water storage portion;
a control unit that controls the water supply mechanism to stop supplying water based on a detection result of the sensor;
The sensor,
A base attached to the water reservoir;
A horizontal section extending from the base section in a direction along the water surface above the water surface of the water stored in the water storage section;
a detection unit that hangs down from the horizontal unit at a position away from the base unit and detects the water surface by abutting the water surface. The steam sterilizer of claim 1, wherein the periphery of the base is covered with an insulator. The steam sterilizer according to claim 2, wherein the cross section is covered with the insulator. The steam sterilizer of claim 1, in which multiple sets of the cross members and the detectors extend in different directions from the base. The steam sterilizer according to claim 1, wherein a male thread is formed at the lower end of the base. The steam sterilizer according to claim 1, wherein the base is columnar, the cross member is disk-shaped and coaxial with the base and is attached to the end of the base, and the detector is a cylindrical wall portion protruding from the underside of the cross member. The steam sterilizer according to claim 6, in which a height adjustment screw portion is formed between the end of the base portion and the cross section.

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