JPH0634808B2 - Control method of steam sterilizer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control method of a steam sterilizer used for sterilizing medical instruments, for example.

[Conventional technology]

The sterilization operation in the conventionally used steam sterilizer is as follows.

The steam supplied from the steam generator (4) is first stored in the steam chamber (1b) to heat (preheat) the sterilization tank (1a) to a predetermined temperature. Then, the vacuum pump (11) is driven to discharge the air in the sterilization tank (1a), and then the solenoid valve (A) in the middle of the steam pipe (6) is opened for a short time to transfer the steam to the steam chamber ( A vacuum process is repeated in which the operation of feeding from 1b) to the sterilization tank (1a) is repeated. After the end of this vacuum stroke, the steam pipe (6)
The steam in the steam chamber (1b) is introduced into the sterilization tank (1a) via the sterilization tank (1a), and the sterilization tank (1a) is filled with steam to reach the sterilization step of sterilizing the sterilized object in the sterilization tank (1a). .

In this sterilization process, the temperature sensor (7) provided at the bottom of the sterilization tank (1a) measures the temperature in the sterilization tank (1a) (for example, the temperature of the drain condensed in the sterilization tank), and this is sterilized. When the temperature reaches the temperature, it is determined to start, sterilization is performed according to a predetermined time, and the process is finished.

[Problems to be solved by the invention] However, when the sterilizer (1) is first operated (during cold start) such as in the early morning or at the beginning of work, sterilization is performed by introducing steam into the steam chamber (1b). The tank (1a) is preheated, but the door that closes the entrance for putting in and out the object to be sterilized with respect to the sterilization tank (1a)
In (2), since the contact portion (area) with the vapor chamber (1b) is small, it is not heated much and remains cold. In addition, the door (2) usually tends to be large in order to maintain heat insulation performance and pressure resistance performance, its heat capacity is larger than that of the object to be sterilized, and the calorific value of steam fed to the sterilization tank (1a). Most of them are spent heating and raising the temperature of the door (2). Therefore, the temperature of the drain discharged from the sterilization tank (1a) is strongly influenced by the temperature rise of the door (2), and even if the drain temperature rises to near the sterilization temperature, the temperature of the object to be sterilized rises too much. I haven't. That is, as shown in FIG. 2, by the drain temperature T _A is also heated to sterilization temperature T _1, the temperature is raised to be sterilized temperature T _B is sterilization temperature T _1, the time t ₁ It is necessary extra and there is a certain temperature difference between them. Also a sterilizer
When (1) is used continuously, since the door (2) is sufficiently heated after the second time, as shown in FIG. 3, the temperature between the drain temperature T _A and the temperature of the sterilized object T _B is Does not make much difference. Therefore, even if the drain temperature T _A reaches the sterilization temperature T ₁ , the object to be sterilized may not actually be heated to the sterilization temperature T ₁ unless the sterilization process is started after a certain period of time. Absent. However, the delay time t ₁ at cold start
And, there is a large difference in the delay time t ₂ when continuously used, and if it is determined that the sterilization time is set to a fixed time in advance, sterilization failure or excessive sterilization will be caused, and proper sterilization will not be performed. become.

[Means for Solving the Problems]

This invention focuses on the above-mentioned problems, and after starting the steam sterilizer, after preheating the inside of the sterilization tank to a predetermined temperature, shifts to the sterilization process and performs the sterilization operation. The method for controlling a steam sterilizer is characterized in that, at the time of startup, it is determined whether or not it is cold startup, and if it is determined that it is cold startup, the transition time to the sterilization process is delayed by a set time. Is.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a steam sterilizer (1) to which the present invention is applied.

In the drawing, (1a) is a sterilization tank for storing the object to be sterilized, and a door (2) for loading and unloading the object to be sterilized is attached to the front surface,
After closing it, it can be sealed to prevent steam from leaking.

In the sterilization tank (1a), the sterilization tank (1a) is
a) Air filter at the tip to let air into
The air pipe (9) to which the (8) is attached is connected, and further the discharge pipe (10) for discharging steam and drain in the sterilization tank (1a).
One end of is connected. The steam and drain discharge pipe (10) has a branch line on the way, one to the vacuum pipe (12) via the vacuum pump (11) and the solenoid valve (E), and the other to the solenoid valve (D). After passing through the piping (13) through the
Reach (14).

Steam chamber (1b) provided around the sterilization tank (1a)
On the other hand, a steam supply pipe (3) extending from the steam generator (4) and a steam pipe (6) having one end connected to the sterilization tank (1a) are respectively connected. Temperature sensor in the middle of the discharge pipe (10)
(7) measures the discharge drain temperature, and the control device (5) receives the signal from the temperature sensor (7) and receives the signal from the sterilizer.
Controls (1) overall.

Next, the operation will be described.

The steam from the steam generator (4) is stored in the steam chamber (1b) through the steam supply pipe (3) and preheats the sterilization tank (1a).

Then, the air in the sterilization tank (1a) is discharged by driving the vacuum pump (11), then the solenoid valve (A) in the middle of the steam pipe (6) is opened for a short time, and the steam chamber (1b) is removed. Enter the vacuum process in which a small amount of steam is repeatedly fed into the sterilization tank (1a).

After completion of the vacuum process, the steam pipe (6) again feeds steam into the sterilization tank (1a) through the steam chamber (1b) to fill the sterilization tank (1a) with high-temperature and high-pressure steam, and the object to be sterilized. The temperature T _B of _{1 is} raised to the set sterilization temperature T ₁ and then the sterilization temperature step is started.

The temperature T _B of the object to be sterilized is estimated by measuring the drain temperature T _A condensed in the sterilization tank (1a) leading to the discharge pipe (10) with the temperature sensor (7).

However, in this case, as described above, since there is a difference between the drain temperature T _A and the sterilized product temperature T _B , even if the drain temperature T _A rises to the set sterilization temperature T ₁ , the sterilization process immediately starts. Instead, the control device (5) counts the delay time of a certain time and then enters the sterilization process. The delay time at this time is set depending on whether or not the steam sterilizer (1) is in the cold start, and at least two types of time are set accordingly.

For example, when the sterilizer (1) is started and the sterilizer (1) is cold, as shown in FIG. 2, the drain temperature T _A is raised to the sterilization temperature T _{1 and} then t _{Since the} object to be sterilized reaches the sterilization temperature T ₁ after ₁ hour, the delay time is t ₁ , and when continuously used, as shown in FIG. 3, the drain temperature T _A ′ and the object to be sterilized are Since the time difference of the temperature rise of the temperature T _B ′ is t ₂ hours, it is the delay time t ₂ . The delay time can be empirically determined by experiments or the like.

The delay times t ₁ and t ₂ may be set before entering the sterilization process, or may be counted during the sterilization process to extend the time of the sterilization process itself. Not something.

Here, the determination as to whether or not the cold start is built in the control device (5) is based on the following control criteria.

That is, 1. When it is first started after midnight.

2. Immediately after starting, the temperature sensor (7) measures the nearby temperature, and this temperature is below a certain temperature.

3. When the temperature sensor (7) is installed in the steam chamber (1b) and the temperature rise detected by the sensor (7) is above a certain band after starting.

4. When the time from the end of operation to the next start is measured and this has exceeded a certain time.

In the above-described state, the control device (5) determines that the cold state is activated, and sterilizes based on a preset delay time.

Such a criterion is that when the temperature sensor (7) is attached to the door (2) and the temperature of the door (2) is measured, the can body and the door (2) are rotatable and the sensor (7 ) Because there is concern about damage to the door
Since the sensor (7) is not attached to (2), it is a criterion for judging whether it is cold start, so of course, by mounting the sensor on the door (2) and measuring the temperature directly, the predetermined control can be performed. You can go.

It should be noted that the criterion for determining whether or not the cold state is started is not limited to the above-mentioned four items, and a large number of criteria can be set depending on the circumstances, and the criteria may be used independently. Alternatively, it may be determined by combining several types.

Alternatively, the temperature condition of the sterilizer is judged by the temporary down time between the operation of the steam sterilizer, etc., and several kinds of delay times are set, and the delay time is judged depending on the case. It is also possible to perform fine control.

〔The invention's effect〕

The present invention is configured as described above, and the sterilization time is set by judging whether it is cold start or not, regardless of the start condition such as cold start or restart. Since proper sterilization is possible, not only sterilization failure can be prevented and the desired sterilization effect can be always obtained, but also excessive sterilization can be prevented, waste of steam and time can be prevented, and operation cost can be reduced. It has various effects such as being able to.

Moreover, despite having such remarkable features, since the processing in the arithmetic unit is simple and small, it is possible to provide a low-cost and highly reliable control circuit.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a steam sterilizer for carrying out the present invention, FIG. 2 is a diagram showing changes in drain temperature and temperature of an object to be sterilized at cold start, and FIG. 3 is cold start. It is a diagram which shows the change of the drain temperature and the temperature to be sterilized other than the time. (1) ... Steam sterilizer (1a) ... Sterilization tank (1b) ... Steam chamber (7) ... Temperature sensor

Claims (1)

[Claims] 1. A steam sterilizer which is preheated to a predetermined temperature in the sterilization tank after starting and then is moved to a sterilization process to perform a sterilization operation. A method for controlling a steam sterilizer, characterized in that, when it is determined that a cold state is started, a transition time to a sterilization process is delayed by a set time.