JPH0264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for sterilizing medical instruments and
Regarding gas sterilizers that sterilize materials, etc., we provide gas sterilizers that can perform sterilization operations when the remaining amount of sterilizing gas, which is normally supplied by pressurized filling in a cylinder, is running low. It was invented for the purpose of obtaining

The gas sterilizer, as shown in FIG.
An exhaust treatment device 9 for removing toxicity from the gas and discharging it through an exhaust pipe 8 equipped with an exhaust valve 6 and an exhaust pump 7, which is connected to a gas source 5 through an air supply pipe 4 provided with an exhaust gas.
This is what made me understand.

To perform gas sterilization, the air supply valve 3 is closed, the exhaust valve 6 is opened, and the exhaust pump 7 is operated to evacuate the inside of the can body 2 to a vacuum state, and then the exhaust valve 6 is closed and the exhaust pump 7 is stopped. Then, the air supply valve 3 is opened, and pressurized sterilization gas flows into the can body 2 from the gas source 5.
Next, the air supply valve 3 is closed and left for a set period of time (approximately 3 hours in the case of ethylene oxide), and the sterilization gas sealed in the can body 2 is allowed to permeate into the objects to be sterilized inside the can body.

After sterilization, the exhaust valve 6 is opened and the exhaust pump 7 is operated, and while filtered clean air is allowed to flow into the can body 2 from a pipe (not shown), the sterilization gas inside the can body is discharged from the exhaust pipe 8. Open the lid 1 and take out the object to be sterilized.

In the gas sterilizer used in this way, a poisonous gas which is pressurized and filled into a cylinder is used as the gas source 5. Normally, ethylene oxide is often used, but in the case of this gas, nitrogen is mixed in to moderately weaken the toxicity, so as the amount of gas in the cylinder decreases, the gas concentration decreases.
Normally, sterilization work is carried out by checking the remaining amount of gas and changing the sterilization time. For example, a cylinder weighing 15 kg can be filled with about 20 kg of ethylene oxide, so you can find out how much gas is left by checking the change in the cylinder's weight. When the remaining amount of gas reaches 10 to 20%, the action of ethylene oxide becomes unstable, and even if sterilization is carried out for the set time, the sterilization effect may not be sufficient.

Also, the pressure when filling the cylinder with gas is 5
Since it is about Kg/cm ² , it is possible to measure the gas pressure to know when the remaining amount of gas is low, but when the gas pressure reaches 3 to 2 Kg/cm ² , the action of the gas becomes unstable.

Note that the action of the sterilizing gas is significantly affected by its temperature, so the sterilization time should be changed depending on the temperature.

The present invention provides a gas sterilizer that detects the pressure of sterilizing gas inside a can and performs sterilization for a time that matches the current gas condition.

Next, an embodiment for ethylene oxide in which the sterilization time is changed by detecting the pressure of the sterilization gas will be described with reference to the flowchart of FIG. 2 showing the progress of the work.

Once the inside of the can 2 containing the objects to be sterilized has been evacuated to a vacuum state as described above, the start button 10
Press to start the sterilization process.

First, in the first process 11, the air supply valve 3 is opened and sterilization gas enters the can body 2.

Next, in a second process 12, the pressure P inside the can is detected. This pressure P is compared in the next first judgment 13 to see if it is equal to the set pressure P ₀ (for example, 1.7 Kg/cm ² ) during sterilization, and if it is equal, the air supply valve 3 is closed in the third process 14. Stop the supply of sterile gas,
Move on to the next second determination 15.

When it is determined in the first judgment 13 that the pressure inside the can does not reach the set pressure P ₀ , the next second judgment 15 is made.
It is determined whether P ₀ −P is greater than 0.3 Kg/cm ² or not. When P ₀ −P is greater than 0.3 Kg/cm ² , that is, when the gas pressure is insufficient for sterilization, a signal is sent to the first processing 11 to continue supplying air to increase the internal pressure, and P ₀ - When P is not greater than 0.3Kg/ ^cm2 , that is, when the gas pressure inside the can is low but still sufficient to sterilize, the following third judgment 16 is applied.
It is determined whether P ₀ −P is greater than 0.2 Kg/cm ² . When this differential pressure is greater than 0.2 Kg/cm ² , the fourth process 17 is performed to extend the set time by 1.5 times by 3 hours. That is, when sterilization is possible despite the low gas pressure, the timer that controls the sterilization time is adjusted to extend the sterilization time.

When P ₀ -P is not greater than 0.2Kg/cm ² , it is determined by the fourth judgment 18 whether P ₀ -P is greater than 0.1Kg/cm ² , and if it is, the sterilization time is determined by the fifth process 19. 1.25 times, that is, the time is extended less than the above.

If P ₀ -P is not greater than 0.1 Kg/cm ² , it is assumed that the sterilization ability is sufficient, and sterilization is performed in the sixth process 20 for 3 hours with an extension factor of 1.

If the sterilization gas pressure is sufficient and P=P ₀ is determined in the first determination 13, the second to fourth determinations are passed and sterilization is performed for 3 hours in the sixth process 20.

When the sterilization for each time period is completed by each process 17, 19, and 20, the end of the sterilization time is judged in a fifth judgment 21, a sterilization completion display 22 is displayed, and the process shifts to the process of removing the object to be sterilized.

Note that when the gas cylinder becomes lighter or the gas pressure decreases, a worker may decide separately whether or not to replace the cylinder with a new one, but in order to have the above-mentioned computer make the decision, The first process 11 includes a sixth determination 23, which receives a signal indicating the weight or gas pressure of the cylinder, as shown by the chain line in FIG. If it is interposed between the second process 12 and the second process 12, when the start button 10 is pressed to start sterilization, a display 24 will automatically appear indicating that the cylinder should be replaced if the gas source is inappropriate. If it is normal, the subsequent processing can be carried out and the sterilization work can be ensured.

The above example is an example in which the sterilization time is adjusted depending on the pressure level of the cylinder. Should the time be extended or not?
If the time is to be extended, it automatically determines by what multiple the set time should be extended and allows the worker to proceed with the work, ensuring reliable sterilization without the need for workers to consider the state of the gas source. It is something that makes you gain. Therefore, the reliability of sterilization can be significantly increased compared to conventional gas sterilization in which only a set time is used.

In addition, in the case of a sterilizing gas such as ethylene oxide whose sterilization ability changes depending on temperature, the sterilization time can be changed depending on the temperature in the same manner as the gas pressure described above.

Figure 3 shows an example of a device that changes the sterilization time according to the degree of difference between the standard temperature _T0 and the temperature T of the sterilizing gas actually flowing into the can, in the case of ethylene oxide. The flowchart is shown as . A temperature sensor (not shown) is installed inside the can body 2 to detect its temperature.

Assuming that the process starts from the end of the pressure reduction process in the can body 2, pressing the start button 10 and opening the air supply valve 3 by the first process 11 is the same as in the case of pressure. Next, in the seventh process 25, the actual temperature T inside the can is measured, and in the seventh judgment 26, T=
Determine whether T ₀ . If T=T ₀ , the third process 14 closes the air supply valve 3 and starts sterilization.

If T = T ₀ , the eighth decision 27 is T ₀ - T
It is determined whether or not T 0 -T is greater than 15°C, and if it is, the supply of sterilizing gas is continued, and if it is not, it is determined by the ninth determination 28 whether T ₀ -T is greater than 10°C. If this is greater than 10℃, the sterilization time is extended by 1.5 times by the fourth treatment 17, and the sterilization time is increased by 10
If it is not larger than ℃, T ₀ according to the tenth judgment 29
It is determined whether -T>5°C. If it is large, the sterilization time is extended by 1.25 times in the fifth process 19, and if it is not large, the sterilization time is sterilized for 3 hours with the extension multiplier 1 in the sixth process 20. The completion of sterilization is carried out at the eleventh judgment 30, and when the sterilization is completed, the display 3 is displayed.
1 is issued, and if it is uncompleted, the sterilization operation is repeated from the beginning.

In this manner, when the sterilization ability of the gas decreases at low temperatures, the sterilization time is extended according to the extent of the decrease, so that sufficient gas sterilization can be performed as a result.

Further, by using both the sterilization time change based on gas temperature and the above-mentioned sterilization time change based on gas pressure, the time can be extended by integrating the time extension due to the temperature difference and the time extension due to the pressure difference. For example, gas pressure
When the temperature is 0.15Kg/cm ² (extension factor 1.25) and the temperature is 12℃ (extension factor 1.5), the timer setting for controlling the sterilization time is set to 3 x 1.25 x 1.5, and the pressure is
Sterilization time can be automatically adjusted by taking temperature into account.

As described above, the present invention provides a gas sterilizer that can perform sterilization appropriate to the situation even when the remaining amount of sterilization gas is low, and that ensures reliable sterilization automatically. It is effective as a device for gaining benefits.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the outline of the gas sterilizer, Figure 2
The figure is a flowchart showing a state in which the sterilization time is changed in response to changes in the sterilization gas pressure to proceed with the work, and FIG. 3 is a similar flowchart corresponding to changes in the temperature of the sterilization gas. 1: Airtight lid, 2: Can body, 3: Air supply valve, 4: Air supply pipe, 5: Gas source, 6: Exhaust valve, 7: Exhaust pump,
8: Exhaust pipe, 9: Exhaust treatment device, 10: Start button, 11: First processing, 12: Second processing, 13: First judgment, 14: Third processing, 15: Second judgment, 1
6: Third judgment, 17: Fourth processing, 18: Fourth judgment, 19: Fifth processing, 20: Sixth processing, 21: Fifth judgment, 22: Display, 23: Sixth judgment, 24: Display, 25: Seventh processing, 26: Seventh judgment, 27: Eighth judgment, 28: Ninth judgment, 29: Tenth judgment, 3
0: Eleventh judgment, 31: Display.

Claims (1)

[Claims] 1. A first process 11 of opening the air supply valve 3 and flowing sterilizing gas into the evacuated can 2, a second process 12 of measuring the internal pressure (P), and measuring the internal canister pressure. and the air supply valve 3 after receiving the output when it is determined in the first judgment that the pressure inside the vessel (P) is equal to the set pressure ( _{P 0 )} .
In response to the third process 14 for closing the canister and the output when the first determination 13 determines that the canister internal pressure (P) is lower than the set pressure (P ₀ ), the canister internal pressure (P) becomes lower than the set pressure (P 0 ). ₀ ) A second judgment 15 compares whether or not the pressure inside the can is higher than the lower allowable pressure, and if the pressure inside the can is lower than the allowable pressure, the output continues to drive the first processing 11. If the pressure is higher than the set pressure (P ₀ ) based on the output of the second judgment 15.
A gas sterilizer characterized in that a plurality of processes 17, 19, 20 for determining the following degree and extending the sterilization time corresponding to the degree, and a fifth determination 21 for determining the end of the sterilization process are combined. 2 First process 11 of opening the air supply valve 3 and supplying sterilizing gas to the evacuated can 2, and controlling the temperature inside the can (T)
A seventh process 25 to measure the inside temperature (T), a seventh judgment 26 to compare the temperature inside the can (T) with the standard temperature (T ₀ ), and a seventh judgment to determine whether the inside temperature (T) is equal to the standard temperature (T ₀ ). In response to the output when it is determined that
In response to the output when the can internal temperature (T) is determined to be lower than the standard temperature (T ₀ ) in the third process 14 and the seventh determination 26, it is determined whether the can internal temperature is equal to or higher than the allowable temperature. Compare the temperature inside the can (T)
If the temperature is below the allowable temperature, the air supply valve 3 will be closed depending on the output.
Eighth determination 27 that continues to drive the opening first process 11
and, if the temperature inside the can (T) is above the allowable temperature, a plurality of processes 17, 19, which determine the extent to which the temperature is below the standard temperature based on the output of the eighth determination 27 and extend the sterilization time in accordance with the extent; 20 and an eleventh determination 30 for determining the end of sterilization processing.