JP3349903B2 - High pressure steam sterilizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure steam sterilizer for performing sterilization using saturated steam.

[0002]

2. Description of the Related Art Conventionally, in order to perform sterilization by a high-pressure steam sterilizer, water is boiled with an on-off valve in a chamber being opened, and after the air bleeding step of removing air in the chamber by the steam is completed, the on-off valve is opened. The process is closed and the process is shifted to a sterilization process in which saturated steam is generated at atmospheric pressure or higher, and sterilization is performed. After the sterilization is completed, the on-off valve is opened when the temperature of the temperature detection sensor reaches 100 ° C., whereby the sterilized product can be taken out.

[0003]

SUMMARY OF THE INVENTION A high-pressure steam sterilizer is
After completion of the air release, the process proceeds to the sterilization process. Therefore, in consideration of the work efficiency, it is necessary to close the on-off valve at the same time as the air in the chamber is exhausted. On the other hand, after completion of the sterilization step, the on-off valve is opened after the pressure in the chamber is reduced. However, when the pressure in the chamber becomes lower than the atmospheric pressure, the lid becomes difficult to open. in this case,
When the on-off valve is opened, outside air enters into the chamber and contamination of the sterilized product occurs.

If the lid is opened when the pressure in the chamber is higher than the atmospheric pressure, vapor in the chamber may be blown out, and depending on the sample, bumping may occur. An appropriate timing for opening the on-off valve is required.

Conventionally, the on-off valve is opened at 100 ° C., so that there is a variation in temperature sensors and control devices. Further, there was a problem that the boiling point was lower than 100 ° C. depending on the altitude of the installation location, and the on-off valve could not be opened at an appropriate timing.

Therefore, the present invention provides a high-pressure steam sterilizer which enables a shift to a sterilization step at the same time as air is removed, and enables the lid to be opened safely and easily after completion of the sterilization step. It is intended to provide a device.

[0007]

In order to achieve the above object, the present invention provides a chamber in which water and a mounting table for an object to be sterilized are housed and which is hermetically closed by a lid, and which is provided in the chamber to boil the water. A heater, an openable and closable valve disposed above the mounting table, and connected to the inside of the chamber, and a temperature detection sensor for detecting a room temperature in the chamber. In the high-pressure steam sterilizer that performs sterilization by closing the on-off valve to shift to the sterilization step after the air release step of performing air release in the chamber,
The temperature in the chamber is detected by the temperature detection sensor, and within a set time, a temperature when showing a stable temperature value is determined as a boiling point temperature, and stored in a memory as a set temperature of the on-off valve, While closing the on-off valve,
After the end of sterilization, a control means is provided for opening and closing the on-off valve when the temperature in the chamber is compared with the set temperature stored in the memory and determined to be equal to the set temperature.

[0008] According to the high-pressure steam sterilizer, the temperature in the chamber is monitored by the temperature detection sensor until the boiling point temperature is reached in the air venting step in which the on-off valve is opened, and it is determined that the air in the chamber has been completely exhausted. Then, the on / off valve is controlled to be closed by the control means, and the process shifts to a sterilization step, where sterilization is performed. In this case, even if the boiling point differs depending on the altitude, or even after the completion of the sterilization process, the inside of the chamber is still preheated, the on-off valve can be properly closed by the boiling point temperature. .

On the other hand, after completion of the sterilization, the temperature in the chamber is gradually decreased, and when it is determined that the temperature is equal to the boiling point temperature stored in the memory, the on-off valve is opened by the control means. As a result, the inside pressure of the chamber and the outside pressure are balanced,
The lid can be opened safely and there is no contamination of the sterilized product.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a sterilizer main body, and an access port 3 serving as an upper opening port is closed by an openable and closable lid 5, so that the inside of the chamber 7 is kept sealed. Water for steam generation, a heater 9 for boiling the water, and a table 11 to be sterilized are provided at the bottom of the chamber 7. The temperature of the water is controlled by a first temperature detection sensor 13. Each is detected by the second temperature detection sensor 15. First
The temperature detection sensor 13 is provided at the bottom of the sterilization apparatus main body 1, and the second temperature detection sensor 15 is provided on the peripheral wall of the sterilization apparatus main body 1 above the mounting table 11. The water for generating steam can be drained by opening the drain valve 19 of the drain pipe 17 provided at the bottom. The high-temperature vapor pressure in the chamber 7 can be released into the discharge container 21 by opening the on-off valve 25 provided in the exhaust pipe 23 connecting the sterilizer main body 1 and the discharge container 21, Each of the valves 19 and 25 is controlled to be openable and closable by a solenoid 27.

The solenoid 27 is controlled by a signal output from the control means 29. FIG.
9 shows a block diagram of FIG. In this block diagram, the first and second temperature detection sensors 13 and 15 are connected to a CPU 33 via an input interface 31, while the heater 9 and the solenoid 27 are connected to a CPU 33 via an output interface 35. . Also,
The input interface 31 is connected to an operation device 36 for turning on / off the power, setting a timer, setting a sterilization temperature, and the like, and the output interface 35 is connected to a display 37 for displaying a temperature or a timer. . The CPU 33 has a built-in clock 39 and a memory 40, and performs arithmetic processing based on each information input via the input interface 31 and outputs appropriate drive signals to the heater 9, the solenoid 27, the display 37, and the like. Has functions.

In the memory 40, during the air bleeding process in the chamber 7, the temperature is detected by the second temperature detection sensor 15 and the temperature at which a stable temperature value is shown within a set time is determined as the boiling point temperature. , The set temperature of the on-off valve.

FIG. 3 is a flowchart for performing a sterilization process. The operation procedure will be described with reference to this flowchart. In step S1, air in the chamber 7 is exhausted by using saturated steam to the outside. This air bleeding step has the content of the flowchart shown in FIG. In FIG. 4, first, the on-off valve 25 is opened in step S10, and the heater 9 is turned on in step S11. Next, in step S12, the first temperature detection sensor 13 monitors the water temperature that rises when the heater 9 is turned on. This monitoring is continued up to the boiling temperature at which the temperature value stabilizes. The stability detection in step S12 is based on the temperature change rate of the water temperature. That is, in step S11, the heater 9
The water temperature in the chamber 7 gradually rises with the lapse of time due to the turning on, and eventually reaches the boiling temperature. When the temperature reaches the boiling temperature, the temperature change rate becomes small and the temperature becomes stable. Therefore, by monitoring this temperature value within a set time, it is detected that the temperature has reached the boiling temperature.
Further, when it is determined that the boiling temperature has been reached at the temperature change rate, if the temperature is detected directly by detecting the boiling temperature, for example, in a high altitude area, the atmospheric pressure is low and the boiling temperature is 100 ° C. , The boiling temperature cannot be detected. Therefore, in the present invention, it is possible to accurately detect the boiling temperature without being affected by conditions such as the atmospheric pressure. Next, in step S13, the chamber 7
The temperature inside is monitored by the second temperature sensor 15 to detect the steam temperature. The stability detection in the step S13 detects the steam temperature based on the temperature change rate. That is,
In step S11, the temperature change rate in the chamber 7 follows the temperature change rate of the water temperature by the steam generated when the heater 9 is turned on, and reaches the boiling point. In this case, if the boiling temperature in the use area is, for example, lower than the atmospheric pressure, the boiling temperature is stabilized at a temperature lower than 100 ° C. When a signal that changes within 5 ° C is detected,
They are considered stable. Further, in step S13, when the temperature change rate in the chamber 7 is stabilized, two cases can be considered. One is when the high-pressure steam sterilizer is started from the initial operation. And the other one is, for example, a case where a continuous sterilization operation is started in which the chamber 7 is hot and then a sterilization process is started while the chamber 7 is hot. The temperature change rate of the latter gradually decreases from a high temperature state. This is a case where the temperature is stabilized at the boiling temperature. In both of the former case and the latter case, stable detection is possible without any support, and a measure can be taken. In step S14, the stable temperature value and the boiling point temperature signal are stored in the memory 38 as the set temperature. On the other hand, the state in the chamber 7 is such that air is removed through the on-off valve 25 due to the generated steam pressure, and the inside of the chamber 7 is filled with saturated steam at atmospheric pressure. In step S15, the state is maintained for a relatively short period of time in order to make the vapor saturated state more complete. In step S16, the on-off valve 25 is closed, and the inside of the chamber 7 is completely closed.
Next, in step S3 of the flowchart shown in FIG.
While controlling the heater temperature of the heater 9, the inside of the chamber 7 is sterilized with saturated steam raised to a pressure higher than the set atmospheric pressure. In step 5, it is determined whether or not the material to be sterilized is dried. If the object does not need to be dried, the value of the temperature sensor 15 is compared with the temperature value stored in the memory 38 in step S14.
When it is determined that the temperature is equal to the set temperature stored in the memory 38, the on-off valve 25 is opened, and the sterilization is completed. Further, in the present control means, a predetermined value may be subtracted from the boiling point temperature and set as a set temperature. This is used because, depending on the sample, a difference may occur between the temperature in the chamber and the temperature of the sample, and bumping occurs when the temperature of the sample is high. In the drying step S7 and the step S9 after the end of the sterilization, if a key operation (input) indicating that the drying step is performed is performed by the operating device 36 before the initial operation is started, the process proceeds to the next step S7. In step S7, the drain valve 19 is opened and the steam is exhausted together with the drainage of the water remaining at the bottom of the chamber 7. Step S
At 9, the heater temperature of the heater 9 is controlled for a predetermined time while the drain valve 19 is opened, and the heater 9 is dried. After the elapse of a predetermined time, the heater 9 is turned off to end the drying. Further, when the process proceeds to the sterilization process, the sterilization is performed by repeating the flowchart shown in FIG.

[0015]

As described above, according to the high-pressure steam sterilizer of the present invention, a correct boiling point temperature signal can be input to the memory of the control means as a set temperature without being affected by external factors. Together with the control means,
Since the on-off valve can be closed properly at the same time as the air in the chamber is released, the transition of the sterilization process is quickened, and the work efficiency is improved.

Further, since the on-off valve can be reliably opened when the inside of the chamber and the outside air pressure are balanced, the lid can be opened safely and contamination of the sterilized product does not occur.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a high-pressure steam sterilizer according to the present invention.

FIG. 2 is a block diagram of a high-pressure steam sterilizer.

FIG. 3 is a flowchart of the entire sterilization process.

FIG. 4 is a flowchart illustrating an air bleeding step.

[Explanation of symbols]

 5 Lid 7 Chamber 11 Sterilization object mounting table 15 Temperature detection sensor 25 On-off valve 29 Control means 40 Memory

Claims (1)

(57) [Claims] 1. A chamber in which water and an object mounting table are stored and sealed by a lid, a heater provided in the chamber for boiling the water, and a chamber disposed above the object mounting table in the chamber. An open / close valve that can be opened and closed and a temperature detection sensor that detects an indoor temperature in the chamber are provided, and when the open / close valve is opened, the open / close valve is closed after an air bleeding step of bleeding the chamber with saturated steam. In a high-pressure steam sterilizer that shifts to a sterilization step and performs sterilization, when the temperature in the chamber is detected by the temperature detection sensor during the air bleeding step in the chamber and a stable temperature value is indicated within a set time period Is determined as the boiling point temperature, stored in a memory as the set temperature of the on-off valve, and the on-off valve is closed. A high-pressure steam sterilizer comprising a control means for opening and closing the on-off valve when it is determined that the internal temperature is equal to the set temperature by comparing and examining the set temperature stored in the memory. .