JP5678267B2 - Steam sterilizer and control method of steam sterilizer - Google Patents

Description

  The present invention relates to a steam sterilizer that kills microorganisms such as bacteria with high-temperature and high-pressure saturated steam, and a method for controlling the steam sterilizer.

  Conventionally, a steam sterilizer for sterilizing medical equipment and the like keeps the inside of a chamber containing an object to be sterilized in a sealed state, heats a heater provided in the chamber, and boils water supplied in the chamber in advance. And sterilizing the object to be sterilized by filling the chamber with high-pressure steam. A conventional steam sterilizer is disclosed in, for example, Japanese Patent Laid-Open No. 9-28771 (Patent Document 1).

  In Japanese Patent Laid-Open No. 9-28771 (Patent Document 1), a chamber having an object to be sterilized and having a heater at the inner bottom, a water storage tank for storing water to be injected into the chamber, a water storage tank and the chamber are communicated with each other. A water supply pipe, an on-off valve that opens and closes the water supply pipe, a water level detector that detects the water level of water injected into the chamber, a timer that measures a predetermined time set in advance, and a control unit, The controller closes the open / close valve when the water level detector detects a predetermined water level during water injection, and starts measuring a predetermined time with a timer. When the predetermined time is measured, the water level detector detects the predetermined water level again. Steam sterilizers have been proposed that start heating with a heater when done.

JP-A-9-28771

  In the case of continuous sterilization in a steam sterilizer, when water is supplied into the chamber in a state where the temperature of the heater immediately after the completion of sterilization is high, the supplied water contacts the heater and steam is rapidly generated. The pressure in the chamber rises rapidly. Even if water is supplied to the chamber in a state where the pressure in the chamber is high, there is a problem that water does not enter the chamber due to the internal pressure of the chamber, making it difficult to supply water into the chamber.

  In the technique disclosed in Patent Document 1, when a predetermined water level is detected, the supply of water is stopped and a predetermined time is measured, and during this predetermined time, the heater does not jump to the extent that water that contacts the heater jumps into the chamber. Is the time to be cooled. For this reason, a long waiting time is required, and the time required to complete the water supply becomes longer, so that the time required for one sterilization process becomes longer and the number of sterilization processes per day is limited.

  The present invention has been made in view of the above problems, and a main object thereof is to provide a steam sterilizer that can supply water into the chamber with a high heater temperature.

  The steam sterilizer according to the present invention includes a chamber capable of storing an object to be sterilized and a heater for heating water supplied into the chamber, and sterilizes the object to be sterilized with steam generated by heating the heater. The steam sterilizer includes a water level sensor that detects the water level in the chamber, and a control unit that controls the operation of the steam sterilizer. The control unit stops water supply to the chamber in response to the water level in the chamber detected by the water level sensor. The control unit continues water supply to the chamber for a predetermined time after the start of water supply to the chamber, regardless of detection of the water level in the chamber by the water level sensor.

  Preferably, the steam sterilizer further includes a water supply path for supplying water to the chamber and a drainage path for discharging water from the chamber. When supplying water to the chamber via the water supply path, the control unit controls the steam sterilizer so that water can be discharged from the chamber via the drainage path.

  Preferably, in the steam sterilizer, the water supply path includes a water supply pump that transfers water in a direction toward the chamber.

  Preferably, in the steam sterilizer, the drainage path includes a valve that opens and closes the drainage path, and the controller opens the drainage path by opening the valve when supplying water to the chamber via the water supply path. To.

  Preferably, the steam sterilizer further includes another water level sensor that detects a lower limit value of the water level in the chamber.

  A method for controlling a steam sterilizer according to the present invention includes a chamber capable of storing an object to be sterilized, a heater for heating water supplied into the chamber, and a water level sensor for detecting the water level in the chamber. This is a steam sterilizer control method for sterilizing an object to be sterilized with steam generated by heating. The method corresponds to the step of continuing water supply to the chamber for a predetermined time after the start of water supply to the chamber, regardless of the detection of the water level in the chamber by the water level sensor, and the water level in the chamber detected by the water level sensor. And stopping the water supply to the chamber.

  According to the steam sterilizer of the present invention, water for the next sterilization process can be supplied into the chamber in a state where the temperature of the heater is high immediately after completion of the sterilization process, and the sterilization process can be continuously performed.

It is a schematic diagram which shows the structure of the steam sterilizer of this Embodiment. It is a block diagram which shows the electric constitution of the steam sterilizer of this Embodiment. It is an expanded sectional view which shows the detail of the connection part shown in FIG. It is a schematic diagram which shows the detail of a drainage path. It is a flowchart which shows the basic operation | movement process of a steam sterilizer. It is a timing chart which shows operation | movement of each apparatus of a steam sterilizer. 3 is a flowchart of a process for cooling a heater. It is a flowchart of the process of supplying water into the chamber.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a schematic diagram showing a configuration of a steam sterilizer 1 according to the present embodiment. As shown in FIG. 1, the steam sterilizer 1 according to the present embodiment includes a chamber 10 that can accommodate an object to be sterilized, typified by a medical instrument such as a gauze or a scalpel. The chamber 10 includes an openable / closable lid 11 attached to one side thereof. By opening the opening / closing lid 11, the object to be sterilized can be carried into and out of the chamber 10. On the other hand, by closing the open / close lid 11, the inside of the chamber 10 is maintained in a sealed state.

  A heater 12 that heats water supplied into the chamber 10 and generates steam is installed at the inner bottom of the chamber 10. The heater 12 is disposed so as to extend along the inner bottom portion of the chamber 10. Above the heater 12, a mounting table 13 on which an object to be sterilized (not shown) can be mounted is provided substantially parallel to the inner bottom portion of the chamber 10.

  An upper limit water level sensor 14 and a lower limit water level sensor 15 for detecting the water level of the water supplied into the chamber 10 are also arranged on the inner bottom portion of the chamber 10 so as to stand from the inner bottom portion. The upper limit water level sensor 14 and the lower limit water level sensor 15 detect that a predetermined amount of water has entered the chamber 10.

  The upper limit water level sensor 14 and the lower limit water level sensor 15 are configured to include a sensor part made of a conductive material such as metal provided at the tip thereof and a root part made of an insulating material typified by ceramic. In the upper limit water level sensor 14 and the lower limit water level sensor 15, the height at which the sensor portion of the upper limit water level sensor 14 protrudes from the bottom of the chamber 10 is greater than the height at which the sensor portion of the lower limit water level sensor 15 protrudes from the bottom of the chamber 10. So that it is formed.

  The upper limit water level sensor 14 detects the upper limit value of the water level in the chamber 10. That is, the steam sterilizer 1 is controlled so that the water supply to the chamber 10 is completed when the upper limit water level sensor 14 is turned on. The water supply stoppage to the chamber 10 is controlled depending on whether or not the water level in the chamber 10 has reached the upper limit water level sensor 14.

  The lower limit water level sensor 15 detects the lower limit value of the water level in the chamber 10. That is, when the water level in the chamber 10 is lower than the position of the sensor unit of the lower limit water level sensor 15, the water in the chamber 10 is not heated by the heater 12, and the steam sterilizer is prevented so as to prevent the chamber 10 from being aired. 1 is controlled.

  A temperature sensor 16 that detects the temperature in the chamber 10 is attached to one inner surface of the chamber 10 that faces the open / close lid 11. The temperature sensor 16 measures the temperature of the gas in the chamber 10.

  The steam sterilizer 1 includes a water tank 20 that stores water injected into the chamber 10. The internal space of the water storage tank 20 includes a liquid phase portion 21 where water is present and a gas phase portion 22 where air is present. The chamber 10 and the water tank 20 include a water supply path 30 that supplies water from the water tank 20 to the chamber 10, a drain path 40 that discharges water from the chamber 10 to the water tank 20, and air from the chamber 10 to the water tank 20. It communicates with an exhaust passage 50 for discharging the air-fuel mixture with water vapor.

  The water supply path 30 includes a water supply pipe 31. One end of the water supply pipe 31 is connected to the liquid phase part 21 inside the water storage tank 20, and the other end is connected to a connection part 17 provided outside the bottom part of the chamber 10. One end of the water supply pipe 31 is connected to a water intake at the bottom of the water storage tank 20. The water supply pipe 31 communicates the water storage tank 20 and the connecting portion 17. The water supply path 30 includes a water supply pump 32 and a water supply electromagnetic valve 33 arranged in the middle of the water supply pipe 31. The water supply pump 32 is arranged on the upstream side (side near the water storage tank 20) of the water supply path 30, and the water supply electromagnetic valve 33 is arranged on the downstream side (side near the chamber 10) of the water supply path 30.

  The water supply pump 32 transfers water in the direction of flowing from the water storage tank 20 toward the chamber 10 to supply water into the chamber 10. The water supply electromagnetic valve 33 is disposed downstream of the water supply path 30 with respect to the water supply pump 32 and opens and closes the water supply path 30. The water supply electromagnetic valve 33 is provided so as to be switchable between an open state in which water can flow from the water storage tank 20 to the chamber 10 and a closed state in which water flow from the water storage tank 20 to the chamber 10 is prohibited.

  The drainage path 40 includes a main drainage pipe 41, a first drainage branch pipe 42, and a second drainage branch pipe 44. One end of the main drain pipe 41 is connected to the connecting portion 17 at the bottom of the chamber 10. One end of each of the first drainage branch pipe 42 and the second drainage branch pipe 44 is connected to the main drainage pipe 41. The other end of the first drain branch 42 is connected to the liquid phase portion 21 inside the water tank 20. The other end of the second drainage branch pipe 44 is connected to the gas phase part 22 inside the water tank 20.

  The drainage path 40 for discharging water and water vapor from the chamber 10 is divided into two systems, the first drainage branch pipe 42 for discharging water and water vapor to the liquid phase part 21 in the water tank 20, and the water tank 20. And a second drainage branch pipe 44 for discharging water vapor to the gas phase portion 22 inside. Water from the chamber 10 toward the water tank 20 can flow from the main drain pipe 41 to the liquid phase portion 21 of the water tank 20 via the first drain branch pipe 42 or from the main drain pipe 41 to the second drainage. It can flow to the gas phase part 22 of the water storage tank 20 via the branch pipe 44.

  In the middle of the first drainage branch pipe 42, a first drainage electromagnetic valve 43 is arranged. The first drain solenoid valve 43 is in an open state in which water can flow from the chamber 10 to the water tank 20 via the first drain branch pipe 42 and in a closed state in which water flow from the chamber 10 to the water tank 20 is prohibited. Are provided to be switchable. In the middle of the second drainage branch pipe 44, a second drainage electromagnetic valve 45 is disposed. The second drainage electromagnetic valve 45 is in an open state in which water can flow from the chamber 10 to the water tank 20 via the second drainage branch pipe 44 and in a closed state in which water flow from the chamber 10 to the water tank 20 is prohibited. Are provided to be switchable.

  The exhaust path 50 includes an exhaust pipe 51. One end of the exhaust pipe 51 is connected to the ceiling part of the chamber 10, and the other end is connected to the gas phase part 22 inside the water tank 20. The exhaust path 50 includes an exhaust electromagnetic valve 52 disposed in the middle of the exhaust pipe 51. The exhaust solenoid valve 52 is provided so as to be switchable between an open state in which gas can flow from the chamber 10 to the water storage tank 20 and a closed state in which gas flow from the chamber 10 to the water storage tank 20 is prohibited.

  The exhaust path 50 forms a path serving as an outlet of a mixture of air and steam when filling the chamber 10 with steam during the sterilization process. Since the other end of the exhaust path 50 is connected to the gas phase part 22 inside the water tank 20, the air-fuel mixture is discharged to the gas phase part 22 inside the water tank 20. The water storage tank 20 is formed with an exhaust port (not shown) for communicating the external space of the water storage tank 20 and the gas phase part 22. This exhaust port is formed with its position adjusted so that gas does not spout from the gas phase part 22 of the water storage tank 20 toward the operator who uses the steam sterilizer 1.

  The steam sterilizer 1 is also provided with an air blowing path 60 that sends air into the chamber 10. The blower path 60 includes a blower pipe 61 having one end connected to the chamber 10, an air filter 62 attached to the other end of the blower pipe 61, a blower pump 63 and a blower electromagnetic valve 64 disposed in the middle of the blower pipe 61. Including. The air filter 62 functions as an intake port for air into the blower pipe 61. The air taken in via the air filter 62 circulates inside the blower pipe 61. The blower pump 63 transfers air in a direction that flows from the other end of the blower pipe 61 toward one end. The blower electromagnetic valve 64 is disposed in the middle of the blower pipe 61 on the side closer to the chamber 10 with respect to the blower pump 63. The blower electromagnetic valve 64 is provided so as to be switchable between an open state in which outside air can flow into the chamber 10 via the blower path 60 and a closed state in which the flow of outside air into the chamber 10 is prohibited.

  The air blowing path 60 sends air into the chamber 10 after the object to be sterilized is sterilized in the chamber 10 of the steam sterilizer 1. The water vapor remaining in the chamber 10 is discharged out of the chamber 10 through the exhaust path 50 due to the pressure of the air sent into the chamber 10. The water vapor inside the chamber 10 is replaced by air with low humidity, whereby a drying process for drying the inside of the chamber 10 is performed. By sending air into the chamber 10, the internal pressure of the chamber 10 is lowered. Thereby, the operator who uses the steam sterilizer 1 can safely open the open / close lid 11 and safely take out the sterilized article from the chamber 10.

  FIG. 2 is a block diagram showing an electrical configuration of the steam sterilizer 1 of the present embodiment. As shown in FIG. 1, the steam sterilizer 1 includes a control unit 70 that controls the operation of the steam sterilizer 1. The control unit 70 is electrically connected to the upper limit water level sensor 14, the lower limit water level sensor 15, and the temperature sensor 16, and a detection value related to the internal state of the chamber 10 is input from each sensor. The control unit 70 also has an input unit 71. An operator who uses the steam sterilizer 1 inputs set values such as a heating temperature, a sterilization time, and a drying time from the input unit 71 to the control unit 70. The control unit 70 further includes a timer 72 that measures a predetermined time. The timer 72 is used to control the sterilization time and drying time of the article to be sterilized, and is used to control the timing of water supply into the chamber 10.

  The control unit 70 corresponds to each control step of the steam sterilizer 1, the heater 12, the exhaust electromagnetic valve 52, the first drain electromagnetic valve 43, the second drain electromagnetic valve 45, the water supply electromagnetic valve 33, the water supply pump 32, and the blower A control signal is output to each device included in the steam sterilizer 1 such as the electromagnetic valve 64 and the blower pump 63. By receiving the control signal from the control unit 70 and appropriately operating each device, the sterilization processing of the article to be sterilized by the steam sterilizer 1 is reliably performed.

  FIG. 3 is an enlarged cross-sectional view showing details of the connecting portion 17 shown in FIG. As shown in FIG. 3, the connecting portion 17 includes a T joint 18 that is a T-shaped pipe joint. A water supply pipe 31 of the water supply path 30 and a main drain pipe 41 of the drainage path 40 are connected to a T-shaped horizontal line portion formed by the T joint 18. A T-shaped vertical line portion formed by the T joint 18 is directly connected to the chamber 10, and a path inside the T joint 18 is connected to a through hole 19 formed in the bottom so as to penetrate the bottom of the chamber 10. ing. A T-shaped vertical line portion of the T joint 18 is fixed to the chamber 10 so as to be integrated with the chamber 10.

  With the T-joint 18 interposed, the water supply pipe 31 communicates with the internal space of the chamber 10, the main drain pipe 41 communicates with the internal space of the chamber 10, and the water supply pipe 31 communicates with the main drain pipe 41. ing. Therefore, the connecting portion 17 functions as a water supply port when supplying water into the chamber 10 and also functions as a discharge port when discharging water from the chamber 10.

  FIG. 4 is a schematic diagram showing details of the drainage path 40. As shown in FIG. 4, in the drainage path 40 of the present embodiment, the main drainage pipe 41 has one end connected to the connecting part 17 at the bottom of the chamber 10, and the main drainage pipe 41 is connected to the first drainage branch pipe 42 and Between the other end branched to the second drainage branch pipe 44, a rising portion 41a rising in the vertical direction is included. The water flowing from the chamber 10 toward the water storage tank 20 flows upward in the vertical direction inside the rising portion 41a. On the downstream side of the main drain pipe 41 with respect to the rising portion 41a (the side close to the water storage tank 20), a top portion 41b disposed at the highest position in the main drain pipe 41 is provided. The top 41b is disposed at a position higher than the water level WL of water inside the chamber 10. The top 41b is arranged at a higher position than the sensor portion of the upper limit water level sensor 14 that defines the upper limit of the water level WL in the chamber 10.

  A capacitor part 46 is formed in the first drainage branch pipe 42 connected to the liquid phase part 21 in the water storage tank 20 of the drainage path 40. The capacitor part 46 is formed in a cylindrical shape in which a plurality of annular portions formed by bending the first drainage branch pipe 42 are concentrically overlapped, and the first drainage branch pipe 42 submerged in the liquid phase part 21 in the water storage tank 20. Increase the tube length. The capacitor unit 46 has a silent function for reducing the temperature of hot water passing through the inside of the capacitor unit 46 and reducing noise when the water is discharged into the water storage tank 20. The capacitor portion 46 is not limited to the above shape, and may have any shape that can increase the length of the first drainage branch pipe 42, such as a meandering shape.

  The water storage tank 20 has a low floor portion 23 whose bottom portion is formed one step lower. The capacitor portion 46 is disposed in a recessed space formed by the low floor portion 23. Therefore, the end portion 47 of the first drainage branch pipe 42 is surely arranged in the liquid phase portion 21, and the wastewater from the chamber 10 flowing through the first drainage branch pipe 42 is surely put into the water in the water storage tank 20. A drainage path 40 is formed so that it can be discharged.

  Operation | movement of the steam sterilizer 1 provided with the above structure is demonstrated below. FIG. 5 is a flowchart showing the basic operation steps of the steam sterilizer 1. The operation of the steam sterilizer 1 in each step for sterilization of an object to be sterilized by the steam sterilizer 1 will be described with reference to the flowchart shown in FIG. First, in a process (S10), the power supply of the steam sterilizer 1 is turned on and the steam sterilizer 1 is started. FIG. 6 is a timing chart showing the operation of each device of the steam sterilizer 1 in the step (S10) and the next step (S20). As shown in FIG. 6, the exhaust solenoid valve 52 is opened when the power is turned on. Thereby, the internal space of the chamber 10 and the gas phase part 22 in the water storage tank 20 communicate with each other, and the air pressure and the external air pressure in the chamber 10 are made constant.

  Next, in step (S20), water supply to the chamber 10 is performed. By opening the water supply electromagnetic valve 33 and starting the water supply pump 32, water supply is started, and water is supplied from the water storage tank 20 to the chamber 10. If the sensor part at the tip of the lower limit water level sensor 15 in the chamber 10 is submerged and then the sensor part at the tip of the upper limit water level sensor 14 is submerged, the water supply is completed. Hereinafter, this water supply process (S20) is demonstrated in detail.

  FIG. 7 is a flowchart of a process for cooling the heater 12 performed in the first half of the water supply step (S20). With reference to FIG. 6 and FIG. 7 together, as shown in the step (S 110), at the start of cooling of the heater 12, the water supply electromagnetic valve 33 is opened and the water supply pump 32 is activated, via the water supply path 30. Water is supplied to the chamber 10. When the cooling of the heater 12 is started, the second drain electromagnetic valve 45 is also opened, and the internal space of the chamber 10 and the gas phase part 22 of the water storage tank 20 are communicated. When water is supplied to the chamber 10, the second drain electromagnetic valve 45 is opened so that the water can be easily put into the chamber 10, so that water can be discharged from the chamber 10 via the drain path 40.

  Subsequently, in a step (S120) shown in FIG. 7, it is determined whether or not a predetermined time has elapsed since the cooling of the heater 12 was started. After a predetermined time has elapsed from the start of water supply, in step (S130), the water supply electromagnetic valve 33 is once closed and the water supply pump 32 is stopped. In the present embodiment, the water supply electromagnetic valve 33 is closed and the water supply pump 32 is stopped after 6 seconds from the start of water supply. At this time, the second drainage electromagnetic valve 45 is kept open.

  Thereafter, in step (S140), it is determined whether or not a predetermined time has elapsed after the feed water pump 32 is stopped. After the predetermined time has elapsed, in the step (S150), the second drain electromagnetic valve 45 is closed, and the process of cooling the heater 12 is completed. In the present embodiment, the second drain electromagnetic valve 45 is closed after 5 seconds from the closing operation of the water supply electromagnetic valve 33 and the stop of the water supply pump 32, that is, after 11 seconds from the start of cooling of the heater 12.

  When the heater 12 in the chamber 10 is in a high temperature state at the start of water supply, when the water supplied into the chamber 10 contacts the heater 12, steam is suddenly generated in the chamber 10 and the pressure in the chamber 10 is reduced. Soars. In a state where the pressure in the chamber 10 is high and the internal pressure of the chamber 10 is higher than the pressure of the water transferred from the feed water pump 32 and reaching the connecting portion 17, the water may enter the chamber 10 even if water is supplied to the chamber 10. Can not. Therefore, in the present embodiment, the second drain electromagnetic valve 45 that controls opening and closing of the drainage path 40 for discharging water from the chamber 10 is opened when water is supplied into the chamber 10.

  In this way, steam generated when water touches the high-temperature heater 12 in the chamber 10 is discharged to the outside of the chamber 10 via the drainage path 40. At this time, the water supplied to the chamber 10 and heated by the pressure of the steam is also discharged to the outside of the chamber 10 via the drainage path 40. As the steam is exhausted from the chamber 10, the pressure in the chamber 10 decreases.

  When the internal pressure of the chamber 10 falls below the water pressure of the water transferred by the water supply pump 32, the water can enter the chamber 10, that is, the water can be supplied to the chamber 10. In this state, the heater 12 is cooled by the low-temperature water supplied into the chamber 10 at the start of water supply, and the temperature of the heater 12 is lower than that at the start of water supply. In this state, when water supplied into the chamber 10 touches the heater 12 to generate steam, high-temperature steam and water are discharged from the chamber 10 via the drainage path 40 as described above.

  The water supply into the chamber 10 and the discharge of the high-temperature steam and water generated in the chamber 10 are repeated until the heater 12 is sufficiently cooled to the extent that no steam is generated when the water touches the heater 12. It is. When the heater 12 is sufficiently cooled, even if water is supplied into the chamber 10 and water comes into contact with the heater 12, steam is not generated and the internal pressure of the chamber 10 does not increase. Water can be continuously and smoothly supplied.

  By keeping the path for discharging water from the chamber 10 open when supplying water into the chamber 10, the water heated by the heater 12 due to the internal pressure of the chamber 10 is discharged from the chamber 10, and then a new low-temperature water is supplied. Can be supplied to the chamber 10. By intermittently supplying low temperature water into the chamber 10, the temperature of the heater 12 can be lowered quickly. That is, the state in which water is difficult to enter the chamber 10 at the beginning of water supply can be changed to a state in which water can continuously enter the chamber 10 in a shorter time. Therefore, when the heater 12 starts water supply in a high temperature state, the time required to complete the water supply can be greatly shortened.

  At this time, after the first water supply to the chamber 10, the water supply pump 32 is stopped in the step (S130) shown in FIG. 7, and the water supply to the chamber 10 is temporarily stopped. By controlling the water supply to the chamber 10 in this way, the water vapor generated in the chamber 10 and the water heated by the heater 12 are reliably pushed out of the chamber 10 by the pressure of the water vapor during the water supply stop time, and discharged. It is discharged from the chamber 10 via the path 40. If the internal pressure of the chamber 10 can be sufficiently reduced during the water supply stoppage time, water can easily flow into the chamber 10 when the water supply pump 32 is restarted and water supply to the chamber 10 is resumed. .

  At this time, as shown in FIG. 6, the water level WL in the chamber 10 is not monitored by the upper limit water level sensor 14 and the lower limit water level sensor 15 for a predetermined time after the start of water supply to the chamber 10. In the present embodiment, the control unit 70 prevents the water level WL in the chamber 10 from being monitored for 11 seconds until the water supply pump 32 is first started, then stopped, and then the second drain electromagnetic valve 45 is closed. Is set. This suppresses the upper limit water level sensor 14 from erroneously detecting the water level WL in the chamber 10.

  That is, when water is supplied into the chamber 10 when the heater 12 is at a high temperature, the water in contact with the heater 12 is heated and the temperature rapidly rises, and a part of the water jumps into the chamber 10. When the splashed water falls on the sensor unit of the upper limit water level sensor 14 and the upper limit water level sensor 14 erroneously detects the water level WL in the chamber 10, the control unit 70 transmits a control signal instructing to stop water supply. As a result, the water supply stops when the amount of water in the chamber 10 is insufficient. When the heater 12 is turned on in this state and heating is started, the inside of the chamber 10 is empty and overheated, which may adversely affect each device of the steam sterilizer 1 and the environment around the steam sterilizer 1.

  Therefore, in the present embodiment, the water level WL in the chamber 10 is not monitored for a predetermined time from the start of water supply, and the water into the chamber 10 is independent of the detection of the water level WL by the upper limit water level sensor 14 and the lower limit water level sensor 15. Supply for a certain period of time. At the beginning of water supply, water supply to the chamber 10 is not controlled by detecting the water level WL in the chamber 10, but instead, water supply is controlled by time. In this way, even if water comes into contact with the high-temperature heater 12 and water jumps in the chamber 10, it is possible to prevent erroneous detection of the water level WL in the chamber 10 by the upper limit water level sensor 14. It can be avoided that the water supply stops when the amount of water in the chamber 10 is insufficient.

  As described above, by supplying water having a low temperature into the chamber 10 during the predetermined time, the temperature of the heater 12 can be sufficiently lowered in a short time to such an extent that no water jumps. After the predetermined time has elapsed, the temperature of the heater 12 is sufficiently low so that water can be continuously supplied into the chamber 10 by the operation of the water supply pump 32. Therefore, the time required to complete the water supply can be greatly shortened.

  Further, in the present embodiment, as shown in FIG. 4, a rising portion 41 a is formed in the main drain pipe 41 of the drainage passage 40, and the top portion 41 b on the downstream side of the rising portion 41 a is the water level WL in the chamber 10. Is placed higher than. A path from the water supply path 30 to the interior space of the chamber 10 via the connecting part 17 at the bottom of the chamber 10, and a gas phase part 22 of the water storage tank 20 from the water supply path 30 via the connecting part 17 and the drainage path 40. When compared with the route to reach, the energy (water head) of water required to flow through the former route is relatively small. That is, the water supplied from the water supply path 30 and flowing via the connecting portion 17 is less likely to flow toward the drainage path 40 and more easily toward the chamber 10.

  Therefore, as shown in FIG. 6, the exhaust solenoid valve 52 is kept open, and the internal space of the chamber 10 and the gas phase part 22 of the water storage tank 20 shown in FIG. When the internal pressure of the chamber 10 is sufficiently reduced and the internal pressure of the chamber 10 and the gas phase part 22 of the water storage tank 20 becomes equal, the water transferred to the connecting part 17 by the water supply pump 32 is increased to the inside of the chamber 10. Part flows in. Therefore, even if the second drainage electromagnetic valve 45 is kept open during the water supply process and the drainage path 40 is kept in a state in which water can be circulated, most of the supplied water flows into the chamber 10 from the connecting portion 17, Water can be reliably supplied into the chamber 10.

  By forming the drainage path 40 so that the energy of the water required to circulate the drainage path 40 becomes larger, the water that has reached the connecting portion 17 from the water supply path 30 flows in the direction of flowing into the chamber 10. It is easy. Therefore, in the present embodiment, control adjustment for preventing water that has reached the connecting portion 17 from the water supply path 30 from flowing into the drainage path 40 is not required. Therefore, a shortage of the flow rate of water flowing into the chamber 10 from the connecting portion 17 can be reliably avoided, and water supply to the chamber 10 can be controlled with simpler control.

  FIG. 8 is a flowchart of a process of supplying water into the chamber 10 performed in the latter half of the water supply process (S20). 6 and 8 together, after the process of cooling the heater 12 shown in FIG. 7 is completed, in step (S210), the water supply electromagnetic valve 33 is opened again, and the water supply pump 32 is restarted. The second drain electromagnetic valve 45 is opened again. At the same time, monitoring of the water level WL in the chamber 10 by the upper limit water level sensor 14 and the lower limit water level sensor 15 is started.

  Subsequently, in step (S220), it is determined whether or not the lower limit water level sensor 15 is in an ON state. If it is determined that the lower limit water level sensor 15 is in the off state, water supply to the chamber 10 is continued, and the lower limit water level sensor 15 is in the on state within a predetermined time (60 seconds in the present embodiment) in the step (S230). To determine whether or not. When the lower limit water level sensor 15 does not turn on within a predetermined time, that is, when the water level WL does not reach the height of the sensor portion of the lower limit water level sensor 15 within the predetermined time, the water supply pump 32 is stopped in the step (S260). Then, the water supply electromagnetic valve 33 is closed, the second drainage electromagnetic valve 45 is closed, and water supply is stopped as a time-out error.

  If it is determined in step (S220) that lower limit water level sensor 15 is in the on state, then in step (S240), it is determined whether upper limit water level sensor 14 is in the on state. If it is determined that the upper limit water level sensor 14 is in the off state, water supply to the chamber 10 is continued, and the upper limit water level sensor 14 is turned on within a predetermined time (60 seconds in the present embodiment) in the step (S250). Judge whether to change. If the upper limit water level sensor 14 is not turned on within a predetermined time, that is, if the water level WL does not reach the height of the sensor portion of the upper limit water level sensor 14 within the predetermined time, the water supply pump 32 is stopped in the step (S260). Then, the water supply electromagnetic valve 33 is closed, the second drainage electromagnetic valve 45 is closed, and water supply is stopped as a time-out error.

  If it is determined in step (S240) that upper limit water level sensor 14 is on, if it is detected that upper limit water level sensor 14 is on after the elapse of a predetermined time (3 seconds in the present embodiment; see FIG. 6), In the step (S270), the water supply pump 32 is stopped, the water supply electromagnetic valve 33 is closed, and the second drainage electromagnetic valve 45 is closed, whereby the water supply to the chamber 10 is stopped and the process of supplying water into the chamber 10 is performed. Complete. In this way, the water supply step (S20) shown in FIG. 5 is completed.

  Returning to FIG. 5, after completion of the water supply step (S20), steam generation in the chamber 10 is started in step (S30). By turning on the heater 12 on the bottom surface in the chamber 10, the water supplied into the chamber 10 is heated by the heater 12, and at the same time, the object to be sterilized placed on the mounting table 13 is also heated.

  Next, in step (S40), a replacement step is performed. When the steam generation step of step (S30) is performed, since the exhaust solenoid valve 52 of the exhaust path 50 is still kept open, water in the chamber 10 is generated by steam generated by heating water by the heater 12. Is pushed out, and the pushed-out air is exhausted to the outside of the chamber 10 through the exhaust path 50. The step of extruding the air in the chamber 10 with water vapor and replacing the air in the chamber 10 with the water vapor is referred to as a replacement step.

  In order to exhaust the air remaining in the chamber 10 out of the chamber 10 as much as possible, the replacement process is continued for 120 seconds after the temperature sensor 16 detects that the temperature in the chamber 10 has reached (boiling point −1) ° C. After 120 seconds, the exhaust solenoid valve 52 is closed and the chamber 10 is sealed. By closing the exhaust electromagnetic valve 52, the internal pressure of the chamber 10 can be increased, and the temperature in the chamber can be increased to 100 ° C. or higher by filling the chamber 10 with superheated steam.

  Next, in step (S50), the heater 12 is kept on until the temperature in the chamber 10 reaches the temperature required for sterilization of the article to be sterilized + 0.5 ° C., and the chamber 10 is heated. For example, the sterilization temperature may be set to 115 ° C, 121 ° C, or 135 ° C. However, although 115 ° C. is a sterilization temperature for sterilizing the chemical solution stored in the bottle, it is considered that there is a temperature difference between the water vapor in the chamber 10 and the liquid in the bottle. Is set to 117 ° C. During the heating, the heater 12 is repeatedly turned on and off as appropriate, and heated to 117.5 ° C. gently.

  When the temperature in the chamber 10 reaches the required temperature for a predetermined sterilization process, next, in step (S60), the sterilization processing of the article to be sterilized is performed for a time longer than the minimum sterilization time at each set temperature. For example, as a condition for satisfying a predetermined number of killed bacteria, sterilization may be performed at 135 ° C. for 7 minutes or more, or sterilization may be performed at 121 ° C. for 24 minutes or more. During the sterilization process, the heater 12 is turned on and off as appropriate, and the temperature inside the chamber 10 is set at a predetermined temperature + 0.5 ° C. to + 1.0 ° C. so that the temperature inside the chamber 10 does not fall below the predetermined sterilization temperature. To manage the temperature.

  After a predetermined time has elapsed in the step (S60) and the sterilization process is completed, in the next step (S70), a steaming process is performed in which the heater 12 is turned off and the water and water vapor in the chamber 10 are discharged to the water tank 20. It is.

  While the internal pressure of the chamber 10 is high, the first drain electromagnetic valve 43 is opened and high temperature water and water vapor are discharged into the water in the water storage tank 20 via the first drain branch pipe 42. Water and water vapor are pushed out of the chamber 10 by the vapor pressure in the chamber 10, and the water and water vapor are discharged into the water in the water storage tank 20. Thereby, since high temperature water and water vapor | steam are cooled with the water in the water storage tank 20, the noise at the time of discharging water and water vapor | steam can be reduced, and the noise reduction is achieved.

  After the internal pressure of the chamber 10 decreases and the water in the chamber 10 is sufficiently discharged, the first drain electromagnetic valve 43 is closed and the second drain electromagnetic valve 45 is opened, and the second drain branch pipe 44 is passed through. The water vapor is exhausted into the air in the water storage tank 20. After the internal pressure of the chamber 10 has sufficiently decreased, the air in the water storage tank 20 is likely to flow back into the chamber 10, and thus air exhausting is performed to discharge water vapor into the air in the water storage tank 20. At this time, almost no water remains in the chamber 10, and the gas is discharged from the chamber 10, so the sound at the time of discharge is not loud, and even if the water vapor is discharged to the gas phase portion 22 in the water tank 20. From the viewpoint of noise, there is no problem.

  For example, 30 seconds after the first drain electromagnetic valve 43 is opened, the first drain electromagnetic valve 43 is closed and the second drain electromagnetic valve 45 is opened at the same time to switch between underwater and air exhaust. Thereafter, the second drain electromagnetic valve 45 may be kept open for 30 seconds.

  When the liquid in the bottle is sterilized at a sterilization temperature of 115 ° C., the bottle may be broken if the temperature and pressure in the chamber 10 are rapidly changed. Therefore, it waits until the temperature in the chamber 10 reaches 110 ° C., and the steam is exhausted at 110 ° C.

  Next, in step (S80), the object to be sterilized is dried. When the steaming step (S70) is completed, the second drain electromagnetic valve 45 is closed, the exhaust electromagnetic valve 52 is opened, and the heater 12 in the chamber and the drying heater (not shown) covering the upper part outside the chamber 10 are cycled. Heat with current. At the same time, the blower electromagnetic valve 64 is opened and the blower pump 63 is activated to blow air into the chamber 10 from the outside via the blower path 60. In this way, the object to be sterilized is dried for a predetermined time.

  In addition, when sterilizing the liquid in a bottle at 115 degreeC sterilization temperature, it replaces with the said drying process and the cooling process which cools a to-be-sterilized thing is performed. In this case, the heater 12 and the above-described drying heater are turned off, the heater is not controlled, and only air is blown into the chamber 10 via the air blowing path 60.

  After a predetermined drying time has elapsed, the heater 12 and the drying heater are stopped, the blower pump 63 is stopped, and the blower electromagnetic valve 64 is closed, whereby the drying is finished, and as shown in step (S90). All steps for sterilization of sterilized products are completed. In this state, the heater 12 is off, and only the exhaust electromagnetic valve 52 that communicates the chamber 10 and the gas phase portion 22 of the water tank 20 is open.

  In the steaming process (S70) and the drying process (S80), water is discharged from the chamber 10, and the water level WL in the chamber 10 decreases. Therefore, after completion of the step (S90), the operation of each device of the steam sterilizer 1 is in the same state as the power-on timing shown in FIG. 6, and the heater 12 is at a high temperature immediately after stopping. In this state, the opening / closing lid 11 of the chamber 10 is opened, the sterilized object to be sterilized is taken out of the chamber 10, and a new object to be sterilized is placed in the chamber 10 to start the next sterilization process. Can do. Even if the next sterilization process is started immediately while the heater 12 is at a high temperature, water can be supplied into the chamber 10 in a short time, and the sterilization process can be performed continuously. Therefore, the time required for one sterilization treatment can be shortened, and the number of sterilization treatments per day can be increased.

  Although there is a part that overlaps with the above description, characteristic configurations of the present embodiment are listed below. The steam sterilizer 1 according to the present embodiment includes a chamber 10 that stores an object to be sterilized, and a heater 12 that heats water supplied into the chamber 10, and the object to be sterilized with steam generated by heating the heater 12. Sterilize. The steam sterilizer includes an upper limit water level sensor 14 that detects the water level in the chamber 10 and a control unit 70 that controls the operation of the steam sterilizer 1. The control unit 70 stops water supply to the chamber 10 in response to the water level in the chamber 10 detected by the upper limit water level sensor 14. The controller 70 continues to supply water to the chamber 10 for a predetermined time after the water supply to the chamber 10 is started, regardless of the detection of the water level in the chamber 10 by the upper limit water level sensor 14.

  In this way, when water supply to the chamber 10 is started in a state where the heater 12 is at a high temperature, the high-temperature heater 12 comes into contact with water and the water jumps in the chamber 10, and the upper limit water level sensor 14 Even if the sensor unit is splashed with water, the detection of water by the upper limit water level sensor 14 is ignored and the water supply is continued for a predetermined time. Therefore, even if water jumps in the chamber 10, it is possible to prevent erroneous detection of the water level WL in the chamber 10 by the upper limit water level sensor 14, and water supply is stopped when the amount of water in the chamber 10 during water supply is insufficient. Can be avoided.

  By continuing to supply low temperature water into the chamber 10, the temperature of the heater 12 can be sufficiently reduced in a short time to such an extent that no water splash occurs. After the predetermined time has elapsed, the temperature of the heater 12 is sufficiently low so that water can be continuously supplied into the chamber 10 by the operation of the water supply pump 32. Therefore, the time required to complete the water supply to the chamber 10 can be greatly shortened. Therefore, the time until the start of the next sterilization process after completion of the sterilization process can be greatly shortened compared to the conventional steam sterilizer, and continuous sterilization can be performed, so the number of sterilization processes per day can be increased. Can do.

  The steam sterilizer 1 according to the present embodiment further includes a water supply path 30 that supplies water to the chamber 10 and a drainage path 40 that discharges water from the chamber 10. When supplying water to the chamber 10 via the water supply path 30, the control unit 70 controls the steam sterilizer 1 so that water can be discharged from the chamber 10 via the drainage path 40.

  In this way, when water supply to the chamber 10 is started while the heater 12 is at a high temperature, the steam generated when the heater 12 touches the water is discharged to the outside of the chamber 10 via the drainage path 40. . When the pressure in the chamber 10 rises due to the generation of steam, water supply to the chamber 10 becomes difficult. However, the internal pressure of the chamber 10 can be reduced by discharging the steam to the outside of the chamber 10, so that a short time is required. Thus, the chamber 10 can be returned to a state where water can be supplied.

  When steam is generated and the internal pressure of the chamber 10 increases, high-temperature water heated by the heater 12 is also pushed out of the chamber 10 and discharged outside the chamber 10. Therefore, when the internal pressure of the chamber 10 decreases, water having a low temperature is supplied to the chamber 10 and the heater 12 comes into contact with the low-temperature water, so that the temperature of the heater 12 can be decreased in a shorter time.

  Water can be continuously supplied into the chamber 10 if the temperature of the heater 12 drops to such an extent that no steam is generated even when the water touches the heater 12. By cooling the heater 12 with low-temperature water, the time required for the temperature of the heater 12 to be lowered can be shortened. As a result, it is possible to continuously supply water into the chamber 10 in a shorter time, and the time required to complete the water supply to the chamber 10 can be shortened.

  Moreover, in the steam sterilizer 1 of the present embodiment, the water supply path 30 includes a water supply pump 32 that transfers water in the direction toward the chamber 10. In this way, since the water pressurized by the water supply pump 32 is supplied to the chamber 10, it becomes possible to allow the water to flow into the chamber 10 while the internal pressure of the chamber 10 is higher. Therefore, when water touches the high-temperature heater 12 and steam is generated in the chamber 10, the water supply to the chamber 10 can be resumed in a shorter time. Therefore, the time required to complete the water supply to the chamber 10 can be reduced. It can be shortened more.

  Moreover, in the steam sterilizer 1 of the present embodiment, the drainage path 40 includes a second drainage electromagnetic valve 45 that opens and closes the drainage path 40. When supplying water to the chamber 10 via the water supply path 30, the control unit 70 opens the second drain electromagnetic valve 45 to open the drain path 40. In this way, by opening / closing the second drain electromagnetic valve 45, it is possible to easily switch from a state in which water cannot be drained from the chamber 10 to a state in which water can be drained from the chamber 10 via the drain path 40. .

  The steam sterilizer 1 of the present embodiment further includes a lower limit water level sensor 15 that detects a lower limit value of the water level in the chamber 10. In this way, if the water level in the chamber 10 is lower than the position of the lower limit water level sensor 15, it can be controlled not to heat the chamber 10 by the heater 12, and the chamber 10 can be reliably prevented from being blown. can do.

  The control method of the steam sterilizer 1 according to the present embodiment includes a chamber 10 that houses an object to be sterilized, a heater 12 that heats water supplied into the chamber 10, and an upper limit water level sensor that detects the water level in the chamber 10. 14, and a method of controlling the steam sterilizer 1 for sterilizing an object to be sterilized with steam generated by heating of the heater 12. The method includes a step of continuing water supply to the chamber 10 regardless of detection of the water level in the chamber 10 by the upper limit water level sensor 14 for a predetermined time after the start of water supply to the chamber 10, and the chamber detected by the upper limit water level sensor 14. Corresponding to the water level in 10, the step of stopping water supply to the chamber 10 is provided.

  In this way, when water supply to the chamber 10 is started while the heater 12 is at a high temperature, the time required to complete the water supply to the chamber 10 can be shortened. Therefore, the time until the start of the next sterilization process after completion of the sterilization process can be greatly shortened compared to the conventional steam sterilizer, and the continuous sterilization process can be performed, so that the number of sterilization processes per day can be increased. it can.

  In the description so far, the example in which the water supply pump 32 is provided in the water supply path 30 and the water transferred from the water storage tank 20 by the water supply pump 32 is supplied to the chamber 10 has been described. However, the steam sterilizer 1 does not necessarily include the water supply pump 32. That is, by appropriately designing the arrangement of the water storage tank 20 and the water supply path 30 for supplying water from the water storage tank 20 to the chamber 10, the water level in the water storage tank 20 and the water level in the chamber 10 can be changed to the chamber 10. If natural water supply is possible, the water supply pump 32 may not be provided. However, it is considered that by providing the water supply pump 32, as described above, it is possible to obtain an effect that the time required to complete the water supply to the chamber 10 can be further shortened.

  In the description of the present embodiment, the example in which the two water level sensors, the upper limit water level sensor 14 and the lower limit water level sensor 15, are arranged in the chamber 10 has been described. The water level sensor is not limited as long as it can prevent the emptying of the chamber 10 and can perform a function used for controlling to stop supplying water by detecting that the water level WL in the chamber 10 has reached a predetermined value. A configuration in which only one water level sensor is arranged in the chamber 10 may be used as long as the above function can be achieved.

  Although the embodiment of the present invention has been described as above, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Steam sterilizer, 10 chambers, 12 heaters, 14 Upper limit water level sensor, 15 Lower limit water level sensor, 17 Connection part, 18 T joint, 19 Through-hole, 20 Water tank, 21 Liquid phase part, 22 Gas phase part, 30 Water supply path , 31 Water supply pipe, 32 Water supply pump, 33 Water supply solenoid valve, 40 Drainage path, 41 Main drainage pipe, 41a Rising part, 41b Top part, 42 First drainage branch pipe, 43 First drainage solenoid valve, 44 Second drainage branch Pipe, 45 second drain solenoid valve, 50 exhaust path, 51 exhaust pipe, 52 exhaust solenoid valve, 70 control unit.

Claims (6)

A chamber capable of storing objects to be sterilized;
A heater for heating water supplied into the chamber;
In a steam sterilizer that sterilizes the object to be sterilized with steam generated by heating of the heater,
A water level sensor for detecting the water level in the chamber;
A controller for controlling the operation of the steam sterilizer,
Prior Symbol controller, a predetermined time after the start of the water supply to the chamber, irrespective of the detection of the water level in the chamber by the water level sensor, continued supply of water to the chamber, after the predetermined time has elapsed, the water level the detected by the sensor in response to the water level in the chamber, that stops the water supply to the chamber, steam sterilizer. A water supply path for supplying water to the chamber;
A drainage path for draining water from the chamber,
The control unit controls the steam sterilizer so that water can be discharged from the chamber via the drainage path when supplying water to the chamber via the water supply path. The steam sterilizer according to claim 1.   The steam sterilizer according to claim 2, wherein the water supply path includes a water supply pump that transfers water in a direction toward the chamber. The drainage path includes a valve for opening and closing the drainage path,
The steam sterilizer according to claim 2 or 3, wherein when the controller supplies water to the chamber via the water supply path, the controller opens the valve to open the drainage path. .   The steam sterilizer according to any one of claims 1 to 4, further comprising another water level sensor that detects a lower limit value of a water level in the chamber. A chamber capable of storing objects to be sterilized;
A heater for heating water supplied into the chamber;
A steam level sterilizer control method, comprising: a water level sensor for detecting a water level in the chamber; and sterilizing the object to be sterilized with steam generated by heating of the heater,
Continuing water supply to the chamber for a predetermined time after the start of water supply to the chamber, regardless of detection of the water level in the chamber by the water level sensor;
A method of controlling a steam sterilizer, comprising the step of stopping water supply to the chamber in response to the water level in the chamber detected by the water level sensor after the predetermined time has elapsed .

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