JPH0431707B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a high-pressure steam sterilizer that performs sterilization using saturated steam.

(Prior art) To perform sterilization using a conventional high-pressure steam sterilizer, water is boiled with the on-off valve in the chamber opened, and after the air removal step, the air in the chamber is removed by the steam. Sterilization is performed by closing the on-off valve and moving to a sterilization process in which saturated steam is produced at a pressure higher than atmospheric pressure.

(Problems to be Solved by the Invention) As mentioned above, the high-pressure steam sterilizer moves to the sterilization process after completing air removal, but when moving from the air removal process to the sterilization process, the pressure inside the chamber is increased to above atmospheric pressure. Therefore, the on-off valve will be closed. If the on-off valve is closed too early, air will remain in the chamber, and the area where air remains may not be able to be sterilized reliably.If the valve is closed too late, the sterilization process will be delayed. This will cause it to shift later, resulting in poor work efficiency.

For this reason, during the air removal process due to steam pressure,
For example, by detecting the temperature of steam discharged from an on-off valve with a temperature sensor and inputting the detected temperature to the control unit, the detected temperature reaches approximately 100℃ while comparing it with a preset temperature in the control unit. Once this is confirmed, the on-off valve is closed after a predetermined period of time.

This method makes it possible to close the on-off valve accurately, but since the boiling point varies depending on the atmospheric pressure,
For example, depending on the area of use, the steam temperature may be 100℃.
A problem occurs in which the on-off valve is not reached, and the on-off valve remains open. This is undesirable in terms of workability, as it requires adjustment work to ensure that the on-off valve closes correctly depending on the location of the shipping destination.

In addition, when performing repeated sterilization operations, the chamber is preheated and hot before entering the next operation.
There was a problem in that the time it took to reach the set temperature was shortened, and the on-off valve closed with incomplete air venting.

Therefore, an object of the present invention is to provide a new high-pressure steam sterilizer that eliminates the above-mentioned problems.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, this invention includes a chamber in which water and an object to be sterilized are stored and sealed with a lid, and a A heater is provided to boil the water, an open/close valve disposed above the object to be sterilized table and communicated with the inside of the chamber, and a temperature detection sensor for detecting the room temperature inside the chamber, In a high-pressure steam sterilizer that performs sterilization by closing the opening/closing valve and proceeding to the sterilization process after the air removal process in which air is removed from the chamber by steam when the valve is opened, the temperature during the air removal process detected by the temperature detection sensor A control means is provided for outputting a drive signal for closing the on-off valve in response to a signal whose rate of change indicates a stable temperature value within a set time.

(Function) According to this high-pressure steam sterilizer, during the air venting process when the on-off valve is opened, the temperature inside the chamber is monitored by the temperature detection sensor until it reaches the boiling temperature.

When the boiling temperature is reached, the temperature value becomes stable. At the same time, air is discharged by steam, and when a stable temperature value is input within a set time, the control means receives the signal and outputs a drive signal to close the on-off valve. In this case, the control means makes judgments based on a stable rate of temperature change within a set time, so even if the boiling point is different in the region or when the chamber is preheated, the sterilization operation can be continued. The on-off valve can be accurately closed even when the air conditioner enters the room.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings of FIGS. 1 to 4.

In the figure, reference numeral 1 designates the main body of the sterilizer, and the upper open opening 3 is closed by a lid 5 that can be opened and closed, so that the interior of the chamber 7 is kept in a sealed state.

Water for steam generation, a heater 9 for boiling water, and a table 11 for placing objects to be sterilized are provided at the bottom of the chamber 7, and the water temperature inside the chamber 7 is determined by a first temperature detection sensor 13. The temperatures are respectively detected by second temperature detection sensors 15. The first temperature detection sensor 13 is provided at the bottom of the sterilizer main body 1, and the second temperature detection sensor 15 is provided on the peripheral wall of the sterilizer main body 1 above the sterilization object mounting table 11.

Water for steam generation can be drained by opening the drain valve 19 of the drain pipe 17 provided at the bottom. In addition, the high temperature vapor pressure in chamber 7 is
By opening the on-off valve 25 provided in the exhaust pipe 23 that connects the sterilizer main body 1 and the discharge container 21, it becomes possible to escape into the discharge container 21, and each valve 1
9 and 25 are controlled by a solenoid 27 to open and close freely.

The solenoid 27 is controlled by a signal output from a control means 29, and a block diagram of the control means 29 is shown in FIG. In this block diagram, the first and second temperature detection sensors 1
3 and 15 via the input interface 31
While connected to the CPU 33, the heater 9 and the solenoid 27 are connected via an output interface 35.
Connected to CPU33. Further, an operating device 36 for turning the power on/off, setting a timer, setting a sterilization temperature, etc. is connected to the input interface 31, and an indicator 37 for displaying the temperature or timer is connected to the output interface 35. It is connected. The CPU 33 has a built-in clock and performs arithmetic processing based on each piece of information input via the input interface 31.
7. Equipped with a function to output appropriate command signals to the display 37 and the like.

FIG. 3 is a flowchart for performing sterilization treatment. The operating procedure will be explained with reference to this flowchart.

In step _S1 , air in the chamber 7 is vented to the outside using saturated steam. This air venting process is based on the flowchart shown in FIG. In Figure 4, first, step
Open the on-off valve 27 in step _S10 , and turn off the heater 9 in step _S11 .
Turn on. Next, in step _S12 , the first temperature detection sensor 13 monitors the water temperature that rises as the heater 9 is turned on. This monitoring continues until the boiling temperature, at which the temperature value stabilizes. Said step S ₁₂
Stable detection is based on the rate of change in water temperature.

That is, in step _S11 , when the heater 9 is turned on, the water temperature in the chamber 7 gradually rises over time, and eventually reaches the boiling temperature. When the boiling temperature is reached, the rate of temperature change decreases and becomes a stable temperature value, so by monitoring this temperature value within a set time, it is detected that the boiling temperature has been reached.

Furthermore, we decided to use the rate of temperature change to detect when the boiling temperature has been reached because temperature detection that directly detects the boiling temperature would result in variations in detected values because, for example, the boiling temperature differs depending on the region with different atmospheric pressure. This is because, in some cases, it may become undetectable.

Therefore, in the present invention, the boiling temperature could be accurately detected without being affected by conditions such as atmospheric pressure.

Next, in step _S13 , the temperature inside the chamber 7 is monitored by the second temperature sensor 15 to detect the steam temperature. The stable detection in step _S13 is to detect the steam temperature based on the rate of temperature change.
That is, in step _S11 , the temperature change rate in the chamber 7 follows the temperature change rate of the water temperature due to the steam generated by turning on the heater 9.
Reach boiling point. In this case, if the boiling temperature in the region of use is lower than atmospheric pressure, the boiling temperature will be stable at less than 100°C, so in this embodiment, the rate of temperature change in the chamber 7 will be 0.5°C in about 3 to 4 minutes.
When a signal that changes within the range of is detected, it is considered to be stable.

Furthermore, in step _S13 , if the temperature change rate in chamber 7 becomes stable, two things are possible.One is when the high-pressure steam sterilizer is started from the initial operation, and the temperature gradually rises from room temperature to boiling. One case is that the temperature is stable, and the other is, for example, a case where continuous sterilization operation is started while the chamber 7 is still hot, and the rate of temperature change in the latter case is:
This is a case in which the temperature gradually decreases from a high temperature state and stabilizes at a boiling temperature. In both of these cases, stable detection is possible without any problem and countermeasures can be taken.

On the other hand, the state inside the chamber 7 is such that air is expelled via the on-off valve 25 due to the above-mentioned pressure generated.
The inside of the chamber 7 is filled with saturated steam at atmospheric pressure.

In step _S14 , the vapor saturation state is maintained for a relatively short period of time in order to make the vapor saturation state more complete. In step S, the on-off valve 25 is closed to completely seal the inside of the chamber 7. Next, in step S3 of the flowchart shown in FIG. ₃ , sterilization is carried out using saturated steam that increases the pressure inside the chamber 7 to a set atmospheric pressure or higher while controlling the temperature of the heater 9. In step _S5 , it is determined whether or not the object to be sterilized has been dried, and if the object does not require drying, sterilization is completed. If it is determined that sterilization is necessary, the process moves to the next step _S7 .

In step _S7 , the drain valve 19 is opened and the water remaining at the bottom of the chamber 7 is drained and the steam is exhausted. In step _S9 , the temperature of the heater 9 is controlled for a predetermined period of time with the drain valve 19 open, and drying is performed. After a predetermined period of time has elapsed, the heater 9 is turned off to complete the drying.

Further, when proceeding to sterilization processing, sterilization is performed by repeating the flowchart shown in FIG. 3. In this example, sterilization treatment at atmospheric pressure or higher has been described, but sterilization treatment can also be performed at atmospheric pressure or lower.

[Effects of the Invention] As explained above, according to the high-pressure steam sterilizer of the present invention, the correct detected temperature can be obtained without being affected by external factors, so it can be used in places with different atmospheric pressures or in consecutive sterilization processes. Even if air is removed, the on-off valve can be properly closed after air removal is completed.

[Brief explanation of drawings]

Fig. 1 is a schematic cutaway side view of the high-pressure steam sterilizer of the present invention, Fig. 2 is a block diagram of the high-pressure steam sterilizer, Fig. 3 is a flowchart of the entire sterilization process, and Fig. 4 is a flowchart explaining the air venting process. It's a chat. 5...Lid, 7...Chamber, 9...Heater,
DESCRIPTION OF SYMBOLS 11...Sterilization object mounting table, 15...Temperature detection sensor, 25...Opening/closing valve, 29...Control device.

Claims (1)

[Claims] 1. A chamber that stores water and a table for placing objects to be sterilized and is sealed with a lid, a heater provided in the chamber to boil the water, and a chamber that is arranged above the table for placing objects to be sterilized and can be opened and closed and communicates with the inside of the chamber. An on-off valve and a temperature detection sensor that detects the indoor temperature inside the chamber are provided, and when the on-off valve is opened, after an air purge step in which air is removed from the chamber with saturated steam, the on-off valve is closed and the process moves to a sterilization step. In a high-pressure steam sterilizer that performs sterilization, the on-off valve is closed upon receiving a signal indicating that the rate of temperature change during the air removal step detected by the temperature detection sensor is a stable temperature value within a set time. A high-pressure steam sterilizer characterized by comprising a control means for outputting a drive signal.