JP2000312709A - Exhaust gas treatment device for use in ethylene oxide gas sterilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently clean exhaust gas for emission and to miniaturize a device for sufficient adsorption of an ethylene oxide gas by connecting to the gas exhaust port of a sterilizing vessel an exhaust gas treatment vessel for treating the ethylene oxide gas, and providing a reflow path through which the exhaust gas from the exhaust gas treatment vessel is made to flow back into the sterilizing vessel. SOLUTION: In an ethylene oxide gas sterilizer, the operations of filling a sterilizing vessel 1 which an ethylene gas to perform sterilization, then exhausting the gas in the sterilizing vessel 1, and introducing air therein to replace gas in the sterilizing vessel 1 are repeated plural times. An exhaust gas treatment vessel 4 for processing the ethylene oxide gas is connected to the sterilizing vessel 1, and a reflow passage 10 through which the exhaust gas is made to flow back into the sterilizing vessel 1 from the exhaust gas treatment vessel 4 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an ethylene oxide gas sterilizer, and more particularly, to an improvement provided with an exhaust gas treatment tank for treating ethylene oxide gas after being used for sterilization.

[0002]

2. Description of the Related Art A conventional ethylene oxide gas sterilizer fills a sterilization tank with ethylene oxide gas.
The contents are sterilized. The sterilized ethylene oxide gas is released into the atmosphere without any treatment, or is discharged into the atmosphere after being treated in an exhaust gas treatment tank.

[0003]

However, if ethylene oxide gas is released into the atmosphere without treatment, it causes air pollution, which is not preferable in terms of environmental health. Further, when the treatment is performed in the exhaust gas treatment tank, there is a disadvantage that the exhaust gas treatment tank becomes large in order to sufficiently adsorb the ethylene oxide gas.

An object of the present invention is to solve the above-mentioned drawbacks, sufficiently purify and discharge exhaust gas, and reduce the size of an exhaust gas treatment tank.

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies and found that in an ethylene oxide gas sterilizer, after sterilization, the gas in the sterilization tank was discharged, and then air was introduced. The operation of replacing the gas in the tank is repeated several times. This work is called aeration. It is good to use the exhaust gas after sterilization for the gas for aeration, and if the gas for aeration is repeatedly sent to the exhaust gas treatment tank, it is gradually purified, so that the exhaust gas treatment tank can be downsized. Having found this, the present invention has been achieved. That is, the present invention provides an ethylene oxide gas in which a sterilization tank is filled with ethylene oxide gas, sterilized, and then the gas in the sterilization tank is exhausted and air is introduced to replace the gas in the sterilization tank a plurality of times. In the sterilizer, an exhaust gas processing tank for processing ethylene oxide gas is connected to the sterilizing tank, and a recirculation path for returning exhaust gas from the exhaust gas processing tank to the sterilizing tank is provided. An outside air introduction passage for introducing outside air through a sterilization filter may be provided in the middle of the return passage. Further, a flow rate adjusting means for further adjusting the flow rate of outside air introduced into the outside air introduction path,
At least one of the sterilization tank and the adsorption tank is provided with a pressure measuring means for measuring the pressure in the tank. Then, it is preferable to provide a flow rate control means for controlling the flow rate of the outside air introduced by the flow rate adjustment means based on the air pressure measured by the air pressure measurement means.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the device of the present invention. Reference numeral 1 denotes a sterilization tank, which has a sterilization gas introduction pipe 2 for introducing ethylene oxide gas into the tank. 3 is
An on-off valve provided on the sterilization gas introduction pipe 2. Reference numeral 4 denotes an exhaust gas treatment tank, which is filled with an adsorbent 5 or a thermal catalyst (not shown). As the adsorbent 5, activated carbon, water,
A known adsorbent for ethylene oxide gas such as dilute sulfuric acid is used. The exhaust gas treatment tank 4 and the sterilization tank 1 are connected by a pipe 6. In the middle of the pipe 6, an on-off valve 7
Having. Reference numeral 8 denotes an exhaust pipe connected to the exhaust gas processing tank 4 and has an on-off valve 9. Reference numeral 10 denotes a recirculation path that connects the exhaust gas processing tank 4 and the sterilization tank 1 and returns the gas processed in the exhaust gas processing tank 4 to the sterilization tank 1, and has an outside air introduction path 11 and an on-off valve 12 on the way. . The outside air introduction passage 11 introduces outside air into the circulation passage 10 through the sterilization filter 13. Reference numerals 14 and 15 denote atmospheric pressure sensors, which are disposed in the sterilization tank 1 and the exhaust gas treatment layer 4, respectively. Reference numeral 16 denotes a flow control valve (flow control means) provided in the outside air introduction passage 11.
Reference numeral 17 denotes a microcomputer as flow rate control means, which inputs the pressure values measured by the pressure sensors 14 and 15 and controls the valve opening and the like so that the flow rate of the flow control valve 16 becomes appropriate. 2).

In this control, the pressure P1 in the sterilization tank 1 is compared with the pressure P2 in the exhaust gas treatment tank 4, and the flow rate F1 of the outside air introduced into the outside air introduction path is determined. The appropriate value of the flow rate F1 for each atmospheric pressure is obtained by various experiments, and this data is input in advance to the storage means, and the atmospheric pressure data stored in this storage means, the actually measured air pressure P1 in the sterilization tank 1 and the measured values of the exhaust gas treatment tank 4 The air pressure P2 is compared with the air pressure P2, and the flow rate F1 of the outside air relating to the closest approximation is set to an appropriate value. A check valve (not shown) is attached to each of the sterilizing gas introduction pipe 2, the pipe 6, the exhaust pipe 8, and the recirculation path 10.

[0008] The exhaust gas treatment apparatus thus configured is
First, on-off valves 7, 9, 12, 16 are closed, and on-off valves 3
Is opened and ethylene oxide gas is introduced into the sterilization tank 1 to sterilize medical instruments and the like placed in the sterilization tank 1. After sterilization, the on-off valve 9 is kept closed, the on-off valves 7 and 12 are opened, and air is introduced into the sterilization tank 1 while the exhaust gas treatment tank 4 is opened.
After feeding the ethylene oxide gas to the adsorbent 5 (or after decomposing it with a thermal catalyst), the operation of returning to the sterilization tank 1 (aeration) is repeated a plurality of times. At the time of this aeration, the air pressure in the sterilization tank 1 and the exhaust gas processing tank 4 is measured by the air pressure sensors 14 and 15, and the measured air pressure data is sent to the microcomputer 17. The microcomputer 17 receives the data and controls the flow control valve 16 to adjust the amount of outside air to be introduced. Then, an exhaust gas treatment tank 4 is provided by an ethylene oxide gas sensor (not shown).
When it is determined that the aeration is completed, for example, by measuring the concentration of ethylene oxide gas in the chamber, the on-off valve 9 is opened and the air is exhausted. At this time, while the exhaust gas exhausted from the exhaust pipe 8 circulates through the exhaust gas treatment tank 4 a plurality of times, the ethylene oxide gas is gradually adsorbed on the adsorbent 5 (gradually decomposed by the thermal catalyst) and purified. Is done. Therefore, the size of the exhaust gas treatment tank 4 can be reduced as compared with the conventional one in which the ethylene oxide gas is passed only once.

Next, another embodiment will be described with reference to the drawings. FIG. 3 is a schematic view of the device of the present invention according to another embodiment. The difference from the above embodiment is that
The point is that an outside air introduction passage 18 is provided in the middle of the pipe 6. The outside air introduction path 18 is for introducing outside air through the sterilization filter 13, similarly to the outside air introduction path 11. With such a configuration, there is an advantage that the efficiency of decomposing ethylene oxide gas can be increased when the exhaust gas treatment tank 4 is filled with a thermal catalyst.

In each of the above embodiments, the sterilizing gas introduction pipe 2, the pipe 6, the exhaust pipe 8, the recirculation path 10, and the outside air introduction path 1
Although pumps are not described in the drawings 1 and 18, they are simply omitted from the drawings, and a pump is provided at a predetermined position to introduce, circulate, and exhaust gas. Also, the pressure sensors 14, 15
Is provided in both the sterilization tank 1 and the exhaust gas treatment tank 4, but may be provided in either one.

[0011]

In summary, according to the present invention, the sterilization tank is filled with ethylene oxide gas and sterilized, and then the gas in the sterilization tank is discharged from a gas outlet, and air is introduced to introduce the gas in the sterilization tank. In the ethylene oxide gas sterilizer repeating the operation of replacing a plurality of times, in the gas outlet of the sterilization tank,
In addition to connecting an exhaust gas processing tank for processing ethylene oxide gas and providing a return path for returning the exhaust gas from the exhaust gas processing tank into the sterilization tank, exhaust gas can be sufficiently purified and released, and A device for sufficiently adsorbing an oxide gas can be miniaturized.

Further, according to the second aspect of the present invention, since the outside air introduction passage for introducing outside air through the sterilization filter is provided in the middle of the reflux passage, the concentration of the ethylene oxide gas contained in the aeration gas can be reduced. The efficiency of aeration can be increased.

Further, in the invention of claim 3, the flow rate adjusting means for adjusting the flow rate of the outside air introduced into the outside air introduction path, and the pressure measuring means for measuring the air pressure in the tank in at least one of the sterilization tank and the adsorption tank. Provide. And, since the flow rate control means for controlling the flow rate of the outside air introduced by the flow rate control means is provided by the air pressure measured by the air pressure measurement means, the concentration of the ethylene oxide gas contained in the aeration gas can be made a desired value, and the aeration can be performed. This has the effect that it can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic view of a first embodiment of the present invention.

FIG. 2 is a block diagram showing control by a flow control unit.

FIG. 3 is a schematic view of a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 sterilization tank 4 exhaust gas treatment tank 5 adsorbent 10 return line 13 sterilization filter

Claims (3)

[Claims] 1. An ethylene oxide gas in which a sterilization tank is filled with ethylene oxide gas and sterilized, and then the operation of discharging the gas in the sterilization tank and introducing air to replace the gas in the sterilization tank is repeated a plurality of times. In the sterilizer, an exhaust gas adsorption tank that adsorbs ethylene oxide gas is connected to the sterilization tank, and a recirculation path that recirculates exhaust gas from the exhaust gas adsorption tank into the sterilization tank is provided. Gas treatment equipment. 2. The exhaust gas treatment device according to claim 1, wherein an outside air introduction passage for introducing outside air through a sterilization filter is provided in the middle of the return passage. 3. A flow rate adjusting means for adjusting a flow rate of the outside air introduced into the outside air introducing passage, and a pressure measuring means for measuring a pressure in the tank in at least one of a sterilization tank and an exhaust gas adsorption tank. 3. The exhaust gas processing apparatus according to claim 2, further comprising a flow rate control unit that controls a flow rate of the outside air introduced by the flow rate adjustment unit based on a pressure measured by a pressure measurement unit.