JPH02213349A - High pressure steam sterilization apparatus - Google Patents

Abstract

PURPOSE:To surely close an opening and closing valve after the venting of air is completed even at a place different in atmospheric pressure or even in a case entering sterilization treatment continuously by closing the opening and closing valve upon the reception of a signal showing a temp. value stable in the temp. change rate at the time of an air venting process detected by a temp. detection sensor within a set time. CONSTITUTION:When the air in a chamber 7 is vented, a control apparatus 29 opens an opening and closing valve 27 to turn a heater 9 ON. Water temp. rising by turning the heater 9 ON is monitored by the first temp. detection sensor 13. This monitoring is continued until boiling temp. stabilizing a temp. value and this temp. value is detected on the basis of the temp. change rate of water temp. Next, the temp. in the chamber 7 is monitored by the second temp. sensor 15 and the temp. of steam is detected on the basis of the temp. change rate. Air is excluded from the chamber 7 through an opening and closing valve 25 by generated steam pressure and the chamber 7 becomes a state filled with saturated steam under atmospheric pressure. The steam saturated state is kept as it is for a relatively short time in order to make said state more perfect and, thereafter, the opening and closing valve 25 is closed to bring the chamber 7 to a perfect hermetically closed state.

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 open, and after the air handling process, the air in the chamber is removed by the steam, the on-off valve is opened. Sterilization is performed by closing the chamber and moving on to the sterilization process, which uses saturated steam at or above atmospheric pressure.

(Problems to be Solved by the Invention) As mentioned above, the high-pressure steam sterilizer shifts to the sterilization process after air removal is completed, but when moving from the air removal process to the sterilization process, the pressure inside the chamber is increased to a pressure higher than atmospheric pressure. In order to increase the amount of water, 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,
rl# By detecting the temperature of steam discharged from the leap valve with a temperature sensor and inputting the detected temperature to the control unit, the detected temperature reached approximately 100°C while comparing it with the 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 differs depending on the atmospheric pressure, for example, depending on the area of use, the steam temperature may not reach 100°C, and the on-off valve will remain open. It will remain as . This is undesirable in terms of workability, such as requiring 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, which shortens the time it takes to reach the set temperature, which causes problems such as the opening/closing valve closing before air venting is complete. there were.

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

[Structure of the Invention] (Means for Solving IMl) In order to achieve the above object, in this invention, water and the object to be sterilized II1. A chamber in which the aX table is housed and sealed with a lid, a heater provided in the chamber to boil the water, and a heater placed above the object to be sterilized table. An on-off valve that communicates with the inside of the chamber and a temperature detection sensor that detects the indoor temperature inside the chamber is provided. In a high-pressure steam sterilizer that performs sterilization by transitioning to a sterilization process with a pause, the humidity change rate during the air handling process detected by the temperature detection sensor generates a signal indicating a stable temperature value within a set time. A control means is provided for outputting a drive signal for closing the on-off valve in response to the drive signal.

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

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 llltll means receives the signal and outputs a drive signal to close the on-off valve. In this case, since the control means makes a judgment based on a stable rate of temperature change within a set time,
Even if the boiling point is different in the region, or even if the chamber is preheated and sterilization operation is subsequently started, the on-off valve can be accurately closed.

(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 indicates a sterilized MW basic body, in which an opening 3 serving as an upper opening is opened by a cover 5 that can be opened and closed, and the inside of a chamber 7 is kept in a sealed state.

At the bottom of the chamber 7 are provided water for steam generation, a heater 9 for boiling water, and a table 11 for objects to be sterilized. They are each detected by a second temperature detection sensor 15. The first temperature detection sensor 13 is dead! l A second temperature detection sensor 15 is provided at the bottom of the apparatus main body 1, and the second temperature detection sensor 15 is mounted on the object mounting table 1.
1 and is provided on the peripheral wall of the sterilizer main body 1.

Water for steam generation can be drained by opening the drain valve 19 of the drain vibe 17 provided at the bottom. In addition, the high temperature steam pressure in the chamber 7 is controlled by an on-off valve 25 provided in an exhaust pipe 23 that connects the sterilizer main body 1 and the discharge container 21.
By opening the valve, it becomes possible to release the liquid into the discharge container 21, and the multi-valve 19.25 is controlled by the solenoid 27 so that it can be opened and closed.

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
．． The second temperature detection sensor 13.15 is connected to the CPLI 33 via an input interface 31, while the heater 9 and the solenoid 27 are connected to the CPLI 33 via an output interface 35. Further, an operation device 36 for turning the power on/off, setting a timer, setting a sterilization temperature, etc. is connected to the input interface 31, and a display device 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, and operates the heater 9. The solenoid 279 is equipped with an Ia function that outputs an appropriate command signal to the indicator 37 and the like.

FIG. 3 is a flowchart for performing sterilization processing.

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 FIG. 4, first, the on-off valve 27 is opened in step Sho,
The heater 9 is turned on in step SI+. Next, in step 312, the water temperature that rises due to turning on the heater 9 is set to the first level.
The temperature detection sensor 13 monitors 731. This monitoring ensures that the temperature value is stable! ! Continue up to temperature. The stability detection in step S is performed based on the rate of change in water temperature.

That is, in step So, when the heater 9 is turned on, the water temperature in the chamber 7 gradually increases 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 detect when the YSM lagoon temperature was reached based on the temperature change rate because temperature detection that directly detects the boiling temperature, for example, differs in the boiling temperature depending on the region with different atmospheric pressure, so the detected value may vary. This is because variations occur, and 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 813, the temperature inside the chamber 7 is monitored by the second temperature sensor 15 to detect the steam temperature.

The stable detection in step 813 detects the steam temperature based on the rate of temperature change.

That is, in step So, 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, and reaches the boiling point.

In this case, if the boiling temperature in the region of use is lower than atmospheric pressure, for example, the boiling temperature will be stable at less than 100°C, but in this embodiment, the temperature change rate in the chamber 7 will be 0° within about 3 to 4 minutes. When a signal that changes within a range of 5°C is detected, it is considered stable.

Furthermore, in step S13, if the temperature change rate in the chamber 7 becomes stable, two things can be considered. One is when the high-pressure steam sterilizer is started from the initial operation, and the temperature gradually rises from room temperature to boiling point. One case is that the humidity is stable at a temperature of While boiling it! !
This is a case where the detection is stable depending on the temperature, and stable detection is possible without any problem in both the former and latter cases, and measures can be taken.

On the other hand, the inside of the chamber 7 is in a state where air is removed through the on-off valve 25 due to the generated pressure, and the inside of the chamber 7 is filled with saturated steam at atmospheric pressure.

In step 814, 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 turned 1#I to completely seal the inside of the chamber 7. Next, in step S3 of the flowchart shown in FIG. 3, sterilization is performed using saturated steam that raises 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 objects to be sterilized are dry, and if the objects do 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 to A-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 enters the air, the on-off valve can be closed accurately after the air handling is completed.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional 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. 1- It is a chart. 5... Lid 7... Chamber 9... Heater 11... Sterilized object mounting table 15... Temperature detection sensor 25... Open/close valve 29... 1. II till ￥A Representative Patent Attorney Hide Miyoshi Kazu 5...Lid 7...Chamber 9...Heater 11...Sterilization object mounting table 15...Temperature detection sensor Figure 2 Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] a chamber that stores water and a table for placing objects to be sterilized and is sealed with a lid; a heater installed in the chamber for boiling the water; and a heater arranged above the table for placing objects to be sterilized and that 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 in the chamber are provided, and when the on-off valve is opened, after an air venting step in which air is removed from the chamber by saturated steam, the on-off valve is closed and the process proceeds to the sterilization step. In a high-pressure steam sterilizer that performs sterilization, a drive that closes the on-off valve upon receiving a signal indicating that the temperature change rate during the air venting process detected by the temperature detection sensor is a stable temperature value within a set time. A high-pressure steam sterilizer characterized by being provided with a control means for outputting a signal.