JP2010249528A - Method for measuring concentration of fumigation gas and instrument using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and instrument for accurately measuring the concentration of the bactericidal/insecticidal gas in a fumigation housing with the elapse of time. <P>SOLUTION: After fumigation gas is introduced into the fumigation housing C, the concentration of the bactericidal/insecticidal gas in the fumigation housing is first measured by an infrared type gas sensor 70 to obtain a first measured value while the concentration of the bactericidal/insecticidal gas in the fumigation housing is subsequently measured by a catalytic combustion type gas sensor DS to obtain a second measured value and the first measured value is divided by the second measured value to obtain a correction value. Thereafter, the concentration of the bactericidal/insecticidal gas in the fumigation housing is intermittently and repeatedly measured with the elapse of time by the catalytic combustion type gas sensor DS and the value obtained by multiplying the measured value by the correction value is intermittently and repeatedly obtained as the gas concentration value in the fumigation housing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fumigation gas concentration measurement method and a fumigation gas concentration measurement device using the method. More specifically, when fumigation objects (for example, cultural assets, arts, etc.) are stored in the fumigation chamber (fumigation chamber) and fumigation gas is put into the fumigation chamber to fumigate the fumigation objects, The present invention relates to a fumigation gas concentration measuring method for measuring a fumigation gas concentration over time, and an apparatus using the method.

Conventionally, the fumigation gas used for fumigation of cultural properties, etc., has been mainly mixed gas of methyl bromide and ethylene oxide (trade name “Ekibon”). Since this conventional fumigation gas (exibone) has both sterilization and insecticidal ability for both methyl bromide and ethylene oxide, sterilization (sterilization and sterilization) has been conventionally performed by measuring the total amount of “exibone” that is put into the fumigation chamber. We were able to grasp the degree of (insecticidal) ability.
For this reason, conventionally, if the concentration of the mixed gas (trade name “EXBON”) is measured using an optical interferometer-type gas concentration meter, the degree of sterilization (sterilization / insecticidal) ability in the fumigation chamber can be ascertained. I was able to.

However, in recent years, the use of methyl bromide contained in the above-mentioned “Ekbon” has been restricted as a measure against ozone holes, and several types of gases other than Ekbon have come to be used for fumigation of cultural properties. It was.
A mixed gas (trade name “Exfume”) of ethylene oxide and HFC134a (R134a) which is a dilution gas is a representative example of such a cultural property fumigation gas, and is currently used in many museums and art galleries.

By the way, as described above, ethylene oxide has a sterilizing and insecticidal ability, but HFC134a (chemical formula: CH2FCF3) contained in the “exfume” does not have a sterilizing and insecticidal ability.
In addition, the concentration ratio of “exfume” ethylene oxide to HFC134a is 1: 2.5, and HFC134a is more common. Further, during fumigation, ethylene oxide is adsorbed on the fumigation object, but HFC134a is hardly adsorbed. For this reason, in the fumigation store, the concentration of HFC134a having no sterilizing / insecticidal ability increases with time.
Therefore, even if the concentration measurement (total amount measurement) of the above “exfume” is performed using an optical interferometer type gas concentration meter (even if it is performed over time), the sterilization (sterilization / insecticing) capability of the fumigation chamber The degree cannot be grasped.

Therefore, in order to grasp the degree of sterilization (sterilization and insecticidal) ability in the fumigation chamber when fumigation is performed using the above “exfume”, the ethylene oxide concentration in the fumigation chamber space in the presence of HFC134a is determined. There is a need to measure.
The concentration of ethylene oxide when fumigating cultural assets using “Exfume” is 1.5 to 2.0% at the beginning of fumigation, and 1% or more after 24 hours.
On the other hand, since ethylene oxide contained in “Exfume” is a flammable gas, it is possible to measure the concentration up to the lower explosion limit concentration (3%) with a catalytic combustion type (catalytic combustion type) sensor.
Therefore, at present, the detection unit having a contact combustion type sensor is used to measure the ethylene oxide concentration in the fumigation chamber during fumigation over time.

FIG. 8 is a principle diagram for explaining the principle of concentration measurement by a detection unit using a contact combustion type sensor.
As shown in the figure, the detection unit 10 is made of platinum or palladium having a high catalytic activity for the oxidation reaction of combustible gas and is heated to a relatively low temperature with a constant current (contact combustion). Type sensor) DS is incorporated. When the combustible gas in the test gas touches the gas detection element, it burns by catalytic action (catalytic combustion), and the heat generated by the combustion increases the electrical resistance of the gas detection element DS. Since the amount of increase in electrical resistance is proportional to the concentration of the combustible gas in the test gas, the concentration can be displayed by the meter M in the electrical circuit (see, for example, Patent Document 1, 0007 to 0009 paragraphs).
The CS in the electric circuit is a temperature compensation element that has been subjected to insensitive processing to compensate for measurement errors due to temperature changes and pressure fluctuations other than gas catalytic combustion. It has a covered structure.
Since fumigation of cultural assets is usually performed with the inside of the fumigation chamber maintained at a negative pressure, it is desirable to use a detection unit that responds to the pressure fluctuation as described above.

Currently, in general, the time-dependent measurement of the ethylene oxide concentration in the fumigation chamber during fumigation is continuously performed using the detector as described above (for example, 24 hours in the case of fumigation for 24 hours). Is going.
Currently, the main component of the gas detection element (contact combustion sensor) of the detection unit 10 that is put into practical use is palladium.
On the other hand, since the chemical formula of HFC134a coexisting with “Exfume” used for fumigation of cultural assets, etc. is CH2FCF3, the F component (fluorine) serves as a catalyst poison to function as a catalyst (main component palladium) of the gas detection element. Reduce.

In the measurement of ethylene oxide concentration in the fumigation chamber, which is generally performed at present, the measurement is made continuously during fumigation, so the gas detection element is in continuous contact with the fumigation gas that is the measurement gas (almost always exposed). ). For this reason, there is a problem that the sensitivity of the gas detection element decreases with time and accurate concentration measurement cannot be performed.
As described above, the concentration ratio of ethylene oxide and HFC134a in “Exfume” is 1: 2.5, which is higher in HFC134a. In addition, during fumigation, ethylene oxide is adsorbed by the fumigation target, whereas HFC134a. Is hardly adsorbed, so that the concentration of HFC134a increases with time and relatively, and if additional dosage is given during fumigation, the concentration of HFC134a increases for the same reason. The action is accelerated, making it more difficult to accurately measure the ethylene oxide concentration.

Therefore, as shown in Patent Document 2, the applicant of the present application intermittently detects the concentration of combustible gas (ethylene oxide) in the fumigation chamber over time and accurately only for a predetermined time. After introducing the fumigation gas into the sensor and measuring the concentration of the combustible gas in the fumigation gas, air containing no fumigation gas is introduced into the contact combustion type gas sensor, and the fumigation gas (and thus catalyst poison) around the sensor is removed. We have already proposed and implemented a fumigation gas concentration measuring device designed to scavenge.
According to such a device, the time that the contact combustion sensor contacts (exposes) the fumigation gas is shortened, thereby suppressing the decrease in sensitivity of the contact combustion sensor, and the combustible gas concentration in the fumigation chamber is reduced. Measurement can be performed with time and more accurately than in the past.

JP 2005-321216 A JP 2007-256131 A

As described above, according to the device described in Patent Document 2, it is possible to suppress a decrease in sensitivity of the contact combustion type sensor by shortening the time during which the contact combustion type sensor contacts the fumigation gas.
However, even with this device, the problem remains that the sensitivity of the contact combustion sensor gradually decreases when operated for a long period of time (fumigation is repeated many times).
The object of the present invention is to solve the above-mentioned problems and to measure the concentration of the gas for sterilization and insecticide in the fumigation chamber over time and more accurately, and the fumigation gas concentration using the method. It is to provide a measuring device.

In order to achieve the above object, the fumigation gas concentration measuring method of the present invention comprises storing a fumigation object in a fumigation chamber, sterilizing / insecticidal and flammable and infrared absorbing gas, -When fumigating a fumigation object by placing a fumigation gas containing a dilution gas that has a weaker infrared absorption than an insecticidal gas and acts as a catalyst poison into the fumigation chamber,
After the fumigation gas is put in the fumigation chamber, first, the concentration of the sterilizing and insecticidal gas in the fumigation chamber is measured with an infrared gas sensor to obtain a first measured value, and then the fumigation chamber with a contact combustion type gas sensor. The concentration of the gas for sterilization / insecticide is measured to obtain a second measured value, and a correction value obtained by dividing the first measured value by the second measured value is obtained. The gas sensor can intermittently repeatedly measure the concentration of the sterilizing / insecticidal gas in the fumigation chamber, and multiply the measured value by the correction value to intermittently repeat the gas concentration value in the fumigation chamber. It is characterized by.
According to this fumigation gas concentration measuring method, the following effects can be obtained.
In the process of fumigation using fumigation gas, which is a mixed gas of sterilization / insecticide gas and dilution gas, the relative concentration of sterilization / insecticide gas to dilution gas is high in the initial stage of fumigation process. As the fumigation progresses, the sterilizing / insecticidal gas is absorbed by the object of fumigation, so that the relative concentration of the sterilizing / insecticidal gas to the dilution gas gradually decreases.
The sterilizing / insecticing gas used in the present invention has a higher infrared absorptivity (higher infrared absorption) than the dilution gas, so the concentration of the sterilizing / insecticing gas in the fumigation gas is measured by an infrared gas sensor. It is possible. The infrared gas sensor has excellent stability and reproducibility of gas sensitivity, and when the relative concentration of the sterilizing / insecticidal gas to the dilution gas is high, the concentration of the sterilizing / insecticidal gas can be accurately measured. is there. However, if the relative concentration becomes low, it becomes difficult to accurately measure the concentration of the sterilizing / insecticidal gas in the fumigation gas with the infrared gas sensor.
On the other hand, the catalytic combustion type gas sensor outputs a signal proportional to the concentration of combustible gas. Since the sterilizing / insecticidal gas used in the present invention is a combustible gas, the contact combustion type gas sensor outputs a signal proportional to the concentration of the sterilizing / insecticidal gas used in the present invention. However, since the fumigation gas used in the present invention contains a diluting gas that acts as a catalyst poison, the sensitivity of the catalytic combustion type gas sensor gradually increases as the measurement time becomes longer overall (fumigation is repeated many times). It will decline.
In this invention, after the fumigation gas is put in the fumigation chamber, the concentration of the sterilization / insecticide gas in the fumigation chamber is first measured by an infrared gas sensor to obtain the first measured value. In the initial stage where the relative concentration with respect to the dilution gas is high, the first measurement value can be accurately obtained by the infrared gas sensor. Since the infrared gas sensor is excellent in stability and reproducibility of gas sensitivity, the first measurement value can be obtained accurately every time no matter how many times fumigation work is performed.
Next, in the present invention, a contact combustion gas sensor is used to measure the concentration of the sterilizing / insecticidal gas in the fumigation chamber to obtain a second measured value, and to correct the first measured value divided by the second measured value. At this time, even if the sensitivity of the catalytic combustion type gas sensor is lowered, the correction value itself can be obtained accurately because the first measurement value is obtained accurately.
Thereafter, in the present invention, the concentration of the gas for sterilization and insecticide in the fumigation chamber is measured intermittently and repeatedly with the contact combustion gas sensor, and the value obtained by multiplying the measured value by the correction value is obtained. As the gas concentration value can be intermittently repeated in the inside, even if the sensitivity of the catalytic combustion type gas sensor has decreased due to long-term operation, the concentration of the sterilizing / insecticidal gas in the fumigation chamber can be accurately measured over time. It becomes possible to do.
Since the above correction is made every time fumigation is performed, accurate gas concentration measurement can be performed over a long period of time.
Desirably, the measurement by the infrared gas sensor is performed at two or more locations in the vertical direction of the space inside the fumigation chamber, and when the measured values coincide with each other, the measured value is set as the first measured value.
In this way, the first measurement value can be obtained more accurately, and thus a more accurate correction value can be obtained.
Desirably, the second measured value itself is also multiplied by the correction value to obtain a gas concentration value in the fumigation chamber.
In this way, the second measured value, which is the first measured value by the catalytic combustion type gas sensor, can be used not only to obtain the correction value but also to obtain the first gas concentration value based on the catalytic combustion type gas sensor. .
In order to achieve the above object, the fumigation gas concentration measuring device of the present invention is a gas concentration measuring device using the fumigation gas concentration measuring method according to claim 1,
First measuring means for obtaining the first measured value by introducing the fumigation gas in the fumigation chamber into an infrared gas sensor and measuring the concentration of the sterilizing / insecticidal gas in the fumigation gas;
Second measuring means for obtaining the second measured value by introducing the fumigation gas in the fumigation chamber into a contact combustion type gas sensor and measuring the concentration of the sterilizing / insecticidal gas in the fumigation gas;
The first measurement value is divided by the second measurement value to obtain the correction value, the correction value is stored, and the value obtained by multiplying the measurement value obtained by the second measurement means by the correction value is then stored in the fumigation chamber. A control unit for obtaining a gas concentration value in the inside,
It is characterized by having.
According to this fumigation gas concentration measuring device, the same effect as that obtained by the fumigation gas concentration measuring method according to claim 1 can be obtained.
Preferably, the introduction path for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor and the introduction path for introducing the fumigation gas in the fumigation chamber into the contact combustion type gas sensor are configured as a common introduction path.
If comprised in this way, the said correction value can be obtained more correctly.
Assuming that the introduction path for introducing the fumigation gas in the fumigation chamber to the infrared gas sensor and the introduction path for introducing the fumigation gas in the fumigation chamber to the contact combustion type gas sensor are configured separately, the introduction path is introduced into the infrared gas sensor. There is a risk that a large difference occurs between the state of the fumigation gas to be produced and the state of the fumigation gas introduced into the catalytic combustion type gas sensor, and the possibility that the correction value cannot be obtained accurately increases.
On the other hand, if the introduction route for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor and the introduction route for introducing the fumigation gas in the fumigation chamber into the contact combustion type gas sensor are configured as a common introduction route, the infrared gas sensor Even if there is a large difference between the state of the fumigation gas introduced into the gas and the state of the fumigation gas introduced into the catalytic combustion type gas sensor, the difference is remarkably reduced. Therefore, the correction value can be obtained more accurately.

The figure which shows the whole fumigation apparatus. The piping and circuit diagram which show one Embodiment of the fumigation gas concentration measuring apparatus which concerns on this invention. The figure which shows the measurement principle of the gas concentration by an infrared type gas sensor. The circuit diagram of an infrared type gas sensor. The figure which shows the specific example of a detection part and an amplifier circuit. The flowchart which shows a measurement sequence. The flowchart which shows a measurement sequence. The principle figure explaining the principle of the density | concentration measurement by the detection part using a contact combustion type sensor.

Embodiments of a fumigation gas concentration measuring method and a fumigation gas concentration measuring device using the method according to the present invention will be described below with reference to the drawings. The fumigation gas concentration measuring device will be mainly described to explain the fumigation gas concentration measurement method.
First, an example of the fumigation device and the fumigation work using the device will be described with reference to FIG. 1, and then the fumigation gas concentration measuring device will be described.

FIG. 1 is a diagram showing the entire fumigation apparatus including the fumigation warehouse C.
A fumigation device 100 shown in FIG. 1 is filled with a temperature adjusting device 101 for keeping the temperature in the fumigation chamber C constant, a decompression device 102 for keeping the inside of the fumigation chamber C in a negative pressure state, and fumigation gas. A fumigation gas container 103, a vaporizer 104 connected to the fumigation gas container 103 via a pipe 121, a fumigation gas main valve 122, a dosing rate adjustment valve 123, and a weighing for weighing the fumigation gas container 103 105, a pipe 125 for supplying the fumigation gas from the vaporizer 104 into the fumigation chamber C through the dosing valve 124, and a fumigation gas for periodically checking and recording the gas concentration in the fumigation chamber C It controls the operation of the concentration measuring device 1, the exhaust device 106 for sending the residual gas in the cabinet to the adsorption device 107, the temperature adjusting device 101, the decompression device 102, the vaporizer 104, the exhaust device 106, and the dosing valve 124. A control panel 110, and a thermometer 111 for measuring the temperature in the fumigation chamber C, and a pressure gauge 112 for measuring the air pressure in the fumigation chamber C. The thermometer 111 and the pressure gauge 112 are each connected to the fumigation control panel 110.

The fumigation work consists of the following dosing process, fumigation process, and exhaust process.
Dosing process:
(1) A fumigation object (for example, a cultural asset or a work of art) B is stored in a fumigation box C and sealed.
(2) The temperature in the fumigation warehouse C is made constant.
This step is performed by the fumigation control panel 110 controlling the temperature adjustment device 101 based on the measured value of the thermometer 111.
(3) Heating the vaporizer 104 to a constant temperature This process is performed by the fumigation control panel 110 controlling the vaporizer 104 based on the measured value of a temperature sensor (not shown) built in the vaporizer 104.
(4) The fumigation gas container 103 is weighed by a weighing device 105.
(5) The inside of the fumigation warehouse C is depressurized by an appropriate amount.
This process is performed by the fumigation control panel 110 controlling the decompression device 102 based on the measured value of the pressure gauge 112.
(6) Open the dosing valve 124 and the fumigation gas main valve 122.
This work is done by workers. The medication valve 124 is an electromagnetic valve, and is operated by an operator operating a switch (not shown) provided in the fumigation control panel 110.
(7) While observing the weighing device 105, the fumigation gas is sent to the vaporizer 104 at an appropriate amount and at an appropriate time by the dosing rate adjusting valve 123.
This work is done by workers. By this operation, an appropriate amount of fumigation gas G is supplied (medicated) into the fumigation chamber C through the vaporizer 104 and the pipe 125 from the fumigation gas container 103.
For example, when the volume of the fumigation warehouse C is 10 cubic meters = 10000 liters and the above-mentioned “exfume” is used as the fumigation gas, the effective sterilant of “exfume” is ethylene oxide. For example, for 1.5%, the dosage of “Exfume” is 1964 g.
For reference, the above dosage in this case can be calculated as follows.
The molecular weight of ethylene oxide is 44. When 44 g of ethylene oxide is vaporized, the volume becomes 22.4 liters.
The ratio of this volume to the volume of fumigation warehouse C = 10,000 liters is
Since 22.4 / 10000 = 0.224%, the magnification for setting the ethylene oxide concentration to 1.5% is 1.5 / 0.224 = 6.696 times.
The ethylene oxide mass at that time is 6.696 &times; 44 = 294.624 g, and the ratio of ethylene oxide in “Exfume” is 15 wt%.
"Exfume dosage" is 294.624 / 0.15 = 1964g
It becomes.
(8) The fumigation gas main valve 122 and the dosing valve 124 are closed.
(9) As will be described in detail later, the fumigation gas concentration measuring device 1 confirms that an appropriate amount of fumigation gas G has been administered.
The dosing process is completed by confirming that the measurement results in the upper, middle, and lower portions, which will be described later, have reached a uniform and required concentration.

Fumigation process:
(10) As will be described in detail later, the gas concentration in the fumigation chamber C is periodically confirmed and recorded by the fumigation gas concentration measuring device 1.

Exhaust process:
(11) The exhaust device 106 sends the residual gas in the cabinet to the adsorption device 107.
This operation is performed by an operator operating a switch (not shown) for operating the exhaust device 106 provided in the fumigation control panel 110.
(12) When the fumigation gas concentration measuring device 1 to be described later confirms that the residual gas concentration in the cabinet is equal to or less than a predetermined value, the exhaust stroke is completed, and all the fumigation work steps are completed. .

FIG. 2 is a piping and circuit diagram showing an embodiment of a fumigation gas concentration measuring apparatus using the fumigation gas concentration measuring method according to the present invention.
As described above, the fumigation gas concentration measuring device 1 stores the fumigation object B in the fumigation chamber C, and has a bactericidal / insecticidal gas having a bactericidal / insecticidal and flammable property and an infrared absorbing property. When fumigating the fumigation object B with the fumigation gas G containing the dilution gas having a weaker infrared absorption than the insecticidal gas and acting as a catalyst poison in the fumigation chamber C, It is a gas concentration measuring device for measuring the density | concentration of the gas for disinfection and insecticide in the fumigation gas G in FIG.
In this embodiment, ethylene oxide is used as the sterilizing / insecticidal gas, and “exfume” having HFC134a as the diluting gas is used as the fumigation gas G.

As shown in FIG. 2, the fumigation gas concentration measuring device 1 introduces the fumigation gas G in the fumigation chamber C into the infrared gas sensor 70 to measure the concentration of the sterilizing / insecticidal gas in the fumigation gas G First measuring means M1 for obtaining measured values;
A second measuring means M2 for introducing the fumigation gas G in the fumigation chamber C into the contact combustion gas sensor DS and measuring the concentration of the sterilizing / insecticidal gas in the fumigation gas G to obtain a second measured value;
The first measurement value is divided by the second measurement value to obtain a correction value, the correction value is stored, and a value obtained by multiplying the subsequent measurement value by the second measurement means M2 with the correction value is obtained. A control unit 60 which obtains a gas concentration value in C;
It has.

  The first measuring means M1 includes an infrared gas sensor 70, a fumigation gas introduction pipe 20 for introducing the fumigation gas G in the fumigation chamber C into the infrared gas sensor 70, and a fumigation gas intervening in the fumigation gas introduction pipe 20 An electromagnetic valve (SV1 to SV3), an air introduction pipe 30 for introducing air A that does not contain fumigation gas G into the infrared gas sensor 70, and an electromagnetic valve for air (SV4-1) interposed in the air introduction pipe 30 And have.

FIG. 3 is a diagram showing the principle of measuring the gas concentration by the infrared gas sensor 70.
The infrared gas sensor 70 amplifies the measurement cell 71, the infrared source 72, the gas detection side band filter 73f corresponding to the detection gas, the gas detection side sensor 73s, the reference side band filter 74f, the reference side sensor 74s, and signals of these sensors. And an amplifier 75 that outputs the gas concentration signal (measurement signal).
The infrared rays emitted from the infrared source 72 reach the gas detection side sensor 73s after the band filter removes the wavelengths other than those absorbed by the test gas.
Since the degree of absorption is proportional to the gas concentration, the concentration can be known.
That is, the infrared gas sensor 70 is a sensor that measures the gas concentration by utilizing the fact that the degree of absorption of infrared rays by gas is proportional to the gas concentration.

In order to measure the concentration of the sterilizing / insecticidal gas in the gas mixture of the sterilizing / insecticidal gas and the dilution gas with the infrared gas sensor 70, the infrared absorption degree of the sterilizing / insecticidal gas to be measured (infrared absorption) Property) must be higher than the degree of infrared absorption by the dilution gas. Since the infrared absorption degree (infrared absorptivity) by ethylene oxide used in this embodiment is several times higher than the infrared absorption degree by HFC134a, it is possible to measure the ethylene oxide concentration in the fumigation gas G with the infrared gas sensor 70. It is.
A gas concentration signal (IR Gas sig) obtained by the infrared gas sensor 70 shown in FIG. 2 is sent to the control unit 60.
FIG. 4 shows an example of a specific circuit diagram of the infrared gas sensor 70.

As shown in FIG. 2, the second measuring means M2 has a catalyst that comes into contact with ethylene oxide, which is a combustible gas in the fumigation gas G, and causes catalytic combustion. A detection unit 10 having a fluctuating catalytic combustion type gas sensor DS and an electric circuit for converting the fluctuation amount of the electric resistance value of the catalytic combustion type gas sensor DS into an electric quantity;
A fumigation gas introduction pipe 20 for introducing the fumigation gas G in the fumigation warehouse C to the contact combustion type gas sensor DS, and fumigation gas solenoid valves (SV1 to SV3) interposed in the fumigation gas introduction pipe 20;
The catalytic combustion type gas sensor DS has an air introduction pipe 30 for introducing air A containing no fumigation gas G, and an air solenoid valve (SV4-1) interposed in the air introduction pipe 30.

The catalytic combustion type sensor DS is composed of the sensor described above with reference to FIG. Further, the detection unit 10 has an electric circuit based on the principle described above with reference to FIG.
Reference numeral 11 denotes an amplifier circuit for amplifying the sensor output from the detection unit 10.

FIG. 5 shows a specific example of the detection unit 10 and the amplifier circuit 11.
As shown in FIG. 5, in this embodiment, in order to compensate for measurement errors due to temperature changes and pressure fluctuations other than catalytic combustion of gas (that is, measurement errors due to temperature changes and pressure fluctuations in the fumigation chamber C), temperature compensation is performed. Similarly to the catalytic combustion type gas sensor DS, the fumigation gas G or air A is also introduced into the element CS.

Since the fumigation of the cultural property or the like in this embodiment is performed with the inside of the fumigation warehouse C maintained at a negative pressure, the detection unit 10 corresponding to the pressure fluctuation as described above is used.
In FIG. 5, DS1 is a gas chamber in which a catalytic combustion type gas sensor DS is accommodated and fumigation gas G or air A is introduced, and CS1 is a gas chamber in which a temperature compensation element CS is accommodated and fumigation gas G or air A is introduced. It is.
The chambers DS1 and CS1 communicate with each other through a communication path 12. A fumigation gas introduction pipe 20 (also an air introduction pipe 30) is connected to the entrance of the chamber DS1 via an infrared gas sensor 70 and a communication pipe 20b, and an exhaust pipe 51 (see FIG. 2) described later is connected to the exit of the chamber CS1. Is done.
A gas concentration signal (CC Gas sig) obtained by the detection unit 10 including the contact combustion type gas sensor DS is sent to the control unit 60.

As shown in FIG. 2, one end of the fumigation gas introduction pipe 20 is connected to an infrared gas sensor 70, and further connected from the infrared gas sensor 70 to a catalytic combustion gas sensor DS via a communication pipe 20 b. The other end of the fumigation gas introduction pipe 20 is branched into three air collection pipes 21, 22 and 23 and connected to the fumigation chamber C.
The sampling tube 21 is connected to the upper part of the fumigation chamber C to form the upper sampling port 21a of the fumigation gas, and the sampling tube 22 is connected to the middle of the fumigation chamber C to form the middle sampling port 22a of the fumigation gas. The sampling tube 23 is connected to the lower part of the fumigation chamber C to form a lower sampling port 23a for the fumigation gas.
The fumigation gas solenoid valves SV1 to SV3, the air filter 24, and the manual operation valve 25 are interposed in the sampling tubes 21, 22, and 23, respectively. All three manually operated valves 25 are manually opened at the start of measurement of the fumigation gas concentration.

  A part of the air introduction pipe 30 is formed of a pipe common to the fumigation gas introduction pipe 20 and one end is connected to the infrared gas sensor 70. Further, the contact combustion type is connected from the infrared gas sensor 70 through the communication pipe 20b. It is connected to the gas sensor DS. The other end of the air introduction pipe 30 is opened to the atmosphere via an air filter 31. The air introduction pipe 30 is provided with the aforementioned air solenoid valve SV4-1.

A pump P and a first switching valve (three-way solenoid valve) SV5 are interposed in the common pipe portion of the fumigation gas introduction pipe 20 and the air introduction pipe 30.
As can be seen from the above, the introduction route for introducing the fumigation gas G in the fumigation chamber C to the infrared gas sensor 70 and the introduction route for introducing the fumigation gas G in the fumigation chamber C to the contact combustion type gas sensor DS are common. It consists of an introduction route.

A bypass pipe 50 is connected to the first switching valve SV5. The first switching valve SV5 is normally switched to the bypass pipe 50 side (see “NO” in the figure).
An exhaust pipe 51 is connected to the other end of the catalytic combustion type gas sensor DS. The exhaust pipe 51 and the bypass pipe 50 are joined at a junction 52, and a second switching valve (three-way) is connected to the tip of the junction pipe 53. (Electromagnetic valve) SV4-2 is provided.

The second switching valve SV4-2 is connected to a fumigation gas return pipe 54 for returning the fumigation gas G after passing through the infrared gas sensor 70 and contacting the contact combustion type gas sensor DS into the fumigation chamber C. . A manual operation valve 55 is provided in the fumigation gas return pipe 54. The manual operation valve 55 is manually opened when measuring the fumigation gas concentration. The second switching valve SV4-2 normally closes the fumigation gas return pipe 54 side (see “NC” in the figure). As will be described later, the second switching valve SV4-2 constitutes an air exhaust means.
The exhaust pipe 51 is provided with a check valve 56 between the junction 52 with the bypass pipe 50 and the contact combustion gas sensor DS.

  The control unit 60 includes storage means (RAM) 80 for storing at least the first measurement value obtained by the infrared gas sensor 70 and the second measurement value obtained by the detection unit 10, and the first measurement value as the second measurement value. Arithmetic means capable of dividing the measured value to obtain a correction value. The correction value is stored in the storage unit 80. The calculation means is calculation means that can obtain a value obtained by multiplying the measurement value obtained by the second measurement means M2 by the correction value.

  The control unit 60 obtains a dosing mode which is a control mode for obtaining the first measurement value, the second measurement value, a correction value obtained by dividing the first measurement value by the second measurement value, and then Over time, the concentration of the sterilizing / insecticidal gas in the fumigation chamber C is measured intermittently with the catalytic combustion gas sensor DS, and the value obtained by multiplying the measured value by the correction value is the gas concentration in the fumigation chamber. A fumigation mode, which is a control mode for intermittently repeating values, is provided, and a mode changeover switch 90 for switching between the dosing mode and the fumigation mode is provided. The control in each mode will be described later.

The controller 60 operates the fumigation gas solenoid valves (SV1 to SV3) and the air solenoid valve (SV4-1) intermittently, as will be described later, and the infrared gas sensor 70 and the catalytic combustion type only for a predetermined time. The fumigation gas G is introduced into the gas sensor DS to measure the concentration of the sterilizing and insecticidal gas in the fumigation gas G, and the air A is introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS to surround the sensors. The operation of scavenging the fumigation gas G is repeatedly executed repeatedly. Reference numeral 40 denotes the control relay board.
In this embodiment, the control unit 60 includes a display unit and a printer for displaying measurement results and the like.

The solenoid valves SV1 to SV3, SV4-1, the first switching valve SV5, the second switching valve SV4-2, and the pump P are electrically connected to the control unit 60, respectively. Control is performed as described later.
The infrared gas sensor 70 and the amplifier circuit 11 described above are connected to the control unit 60, and an output signal (gas concentration signal) from the infrared gas sensor 70 and the amplifier circuit 11 is an A / D converter included in the control unit 60. Are subjected to A / D conversion, subjected to predetermined calculation processing, and digitally displayed as a concentration measurement result on the display unit. The measurement result can be printed out by a printer.

The control unit 60 has a timer function, and this timer mechanism allows a user of this measuring apparatus to set a measurement standby time. Based on the measurement waiting time set by the user, the controller 60 controls the solenoid valves SV1 to SV3, SV4-1, the first switching valve SV5, the second switching valve SV4-2, and the pump P as described later. Operate to measure the ethylene oxide concentration in the fumigation chamber C over time. When performing the measurement operation, the manual operation valves 25 and 55 are opened in advance as described above. As described above, the first switching valve SV5 is normally switched to the bypass pipe 50 side, and the second switching valve SV4-2 is normally closed to the fumigation gas return pipe 54 side.
The control unit 60 is configured by a microcontroller in which a calculation / control program that enables the calculation and control as described above is stored.

Hereinafter, the measurement sequence by the control unit 60 will be described in correspondence with each process in the fumigation operation described above.
6 and 7 are flowcharts showing a measurement sequence by the control unit 60.
FIG. 6 shows a sequence in the medication mode, and FIG. 7 shows a sequence in the fumigation mode. The sequence in the fumigation mode shown in FIG. 7 shows a case where the measurement operation of the fumigation gas G is set to be performed every 60 minutes by the timer provided in the control unit 60 for 3 minutes.

  When performing the above-mentioned dosing process of the fumigation operation, after performing the operations (1) to (8) in the dosing process, that is, after closing the fumigation gas main valve 122 and the dosing valve 124, In order to perform the operation, that is, the operation for confirming that the fumigation gas G has been administered in an appropriate amount by the fumigation gas concentration measurement device 1, the mode changeover switch 90 is set to the administration mode and the fumigation gas concentration measurement device 1 is operated. Thereby, the control part 60 performs the following sequence shown in FIG.

(1) Measurement starts in step ST1, and gas replacement in the sampling tubes 21, 22, 23 is performed as follows in steps ST2-7.
(2) In step ST2, the pump P is operated, the electromagnetic valve SV1 of the sampling tube 21 (CH.1) is turned on (opened), and the second switching valve SV4-2 is moved to the fumigation gas return pipe 54 side. Then, the fumigation gas G in the fumigation chamber C is sucked to the first switching valve SV5 through the sampling tube 21 for 58 seconds.
At this time, as described above, the first switching valve SV5 is switched to the bypass pipe 50 side, and the second switching valve SV4-2 is switched to the fumigation gas return pipe 54 side. The fumigation gas G is returned to the fumigation chamber C through the bypass pipe 50, the second switching valve SV4-2, and the fumigation gas return pipe 54 without being introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS.
(3) In step ST3, the solenoid valve SV1 of the sampling tube 21 (CH.1) is turned off (closed) and the pump P is stopped (the operation takes 2 seconds).

(4) In step ST4, the pump P is activated and the solenoid valve SV2 of the sampling tube 22 (CH.2) is turned on (opened), and the fumigation gas G in the fumigation chamber C is supplied through the sampling tube 22 for 58 seconds. Suction to 1 switching valve SV5.
At this time, as described above, the first switching valve SV5 has been switched to the bypass pipe 50 side, and the second switching valve SV4-2 has been switched to the fumigation gas return pipe 54 side. The fumigation gas G is returned to the fumigation chamber C through the bypass pipe 50, the second switching valve SV4-2, and the fumigation gas return pipe 54 without being introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS.
(5) In step ST5, the electromagnetic valve SV2 of the air sampling tube 22 (CH.2) is turned off (closed) and the pump P is stopped (the operation takes 2 seconds).

(6) In step ST6, the pump P is operated, the solenoid valve SV3 of the sampling tube 23 (CH.3) is turned on (opened), and the fumigation gas G in the fumigation chamber C is first passed through the sampling tube 23 for 58 seconds. Suction to the switching valve SV5.
At this time, as described above, the fumigation gas G sucked through the sampling tube 23 is returned to the fumigation chamber C through the bypass pipe 50, the second switching valve SV4-2, and the fumigation gas return pipe 54.
(7) In step ST7, the solenoid valve SV3 of the air sampling tube 23 (CH.3) is turned off (closed), and the pump P is stopped (these operations take 2 seconds).

  The gas in the sampling tubes 21, 22, and 23 is filled with the fumigation gas G by the operations in steps ST2 to ST7 as described above. In steps ST2 to ST7, the fumigation gas G is introduced up to the first switching valve SV5, but is returned to the fumigation chamber C without being introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS. , Measurement of ethylene oxide concentration in fumigation gas G is not performed.

The measurement operation is performed after step ST8.
In this embodiment, first, in steps ST8 to ST17, the concentration of the sterilizing / insecticidal gas in the fumigation chamber C is measured by the infrared gas sensor 70 to obtain the first measured value, and then in steps ST20 to ST20 shown in FIG. In ST37, the concentration of the sterilizing / insecticidal gas in the fumigation chamber C is measured by the catalytic combustion gas sensor DS to obtain the second measured value, and the corrected value obtained by dividing the first measured value by the second measured value is obtained. Then, with time, the concentration of the sterilizing / insecticidal gas in the fumigation chamber C is measured intermittently with the catalytic combustion gas sensor DS, and the value obtained by multiplying the measured value by the correction value is stored in the fumigation chamber C. The gas concentration value in can be repeated intermittently.

(8) In step ST8, a measurement operation for obtaining the first measurement value is started. First, zero adjustment is performed. That is, the pump P is operated, the air solenoid valve SV4-1 is turned on (opened), the first switching valve SV5 is placed on the infrared gas sensor 70 and the catalytic combustion gas sensor DS side, and the second changeover valve SV4-2. Is switched to the air exhaust side (see “NO” in FIG. 2), and air is introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS for 38 seconds. The air introduced into the infrared gas sensor 70 and the contact combustion gas sensor DS passes through the measurement cell 71 of the infrared gas sensor 70 and contacts the contact combustion gas sensor DS via the communication pipe 20b, and then the exhaust pipe 51 and the merging pipe 53. , And the second switching valve SV4-2.
The zero adjustment is performed by the control unit 60 setting the measurement value to zero (that is, resetting the measurement value) when the output of the infrared gas sensor 70 is stabilized during the air introduction.
After the zero adjustment (that is, after 38 seconds), the air solenoid valve SV4-1 is closed.

(9) The air solenoid valve SV4-1 is closed, and in step ST9, the solenoid valve SV1 of the sampling tube 21 (CH.1) is turned on (opened), and the second switching valve SV4-2 is turned on as a fumigation gas. Switching to the return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS through the air collection pipe 21 for 20 seconds, and the gas for sterilization and insecticide in the fumigation gas G (oxidation) The concentration of ethylene is measured by the infrared gas sensor 70. Thereby, the ethylene oxide concentration in the upper part in the fumigation warehouse C is measured.
The fumigation gas G is also introduced into the catalytic combustion type gas sensor DS, but no measurement is performed by the catalytic combustion type gas sensor DS (until the mode changeover switch 90 is turned on) until the first measurement value is obtained (until step ST19). When in the dosing mode, the signal from the catalytic combustion gas sensor DS is ignored by the control unit 60).
In the measurement of ethylene oxide concentration, the control unit 60 calculates the gas concentration when the output of the infrared gas sensor 70 is stabilized during the introduction of the fumigation gas G, and the result is stored in the storage means 80 and displayed. This is done by displaying on the part (60).
The fumigation gas G introduced into the infrared gas sensor 70 and the catalytic combustion gas sensor DS is brought into contact with the catalytic combustion gas sensor DS, and then the exhaust pipe 51, the merging pipe 53, the second switching valve SV4-2, and the fumigation gas. It returns to the inside of the fumigation warehouse C (the upper part of the fumigation warehouse C) through the return pipe 54.
After the concentration measurement (20 seconds after the electromagnetic valve SV1 is turned on), the electromagnetic valve SV1 of the sampling tube 21 (CH.1) is closed (turned OFF).
(10) The electromagnetic valve SV1 is closed and the pump P is stopped for 2 seconds in step ST10.

(11) In step ST11, the pump P is operated, and similarly to step ST8, the air solenoid valve SV4-1 is turned on (opened), and the second valve SV4-2 is turned on the air exhaust side ("NO" in FIG. 2). The air solenoid valve SV4-1 is closed after air is introduced into the infrared gas sensor 70 for 38 seconds and zero adjustment is performed. The air introduced into the infrared gas sensor 70 is discharged into the atmosphere through the exhaust pipe 51, the junction pipe 53, and the second switching valve SV4-2.

(12) The air solenoid valve SV4-1 is closed, and in step ST12, the solenoid valve SV2 of the sampling tube 22 (CH.2) is turned on (opened), and the second switching valve SV4-2 is turned on as a fumigation gas. Switching to the return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the infrared gas sensor 70 through the air sampling pipe 22 for 20 seconds, and the measurement, storage and display of the ethylene oxide concentration in the fumigation gas G are the same as before. Do. Thereby, the ethylene oxide concentration in the middle of the fumigation chamber C is measured.
The fumigation gas G introduced into the infrared gas sensor 70 is returned to the fumigation chamber C as before.
After the concentration measurement (20 seconds after the solenoid valve SV2 is turned on), the solenoid valve SV2 of the air sampling tube 22 (CH.2) is closed (turned off).
(13) The electromagnetic valve SV2 is closed and the pump P is stopped for 2 seconds in step ST13.

(14) The pump P is operated in step ST14, the air solenoid valve SV4-1 is turned on (opened), and the second valve SV4-2 is turned on the air exhaust side ("NO" in FIG. 2), as in step ST8. The air solenoid valve SV4-1 is closed after air is introduced into the infrared gas sensor 70 for 38 seconds and zero adjustment is performed. The air introduced into the infrared gas sensor 70 is discharged into the atmosphere as before.

(15) The air solenoid valve SV4-1 is closed, and in step ST15, the solenoid valve SV3 of the air sampling tube 23 (CH.3) is turned on (opened), and the second switching valve SV4-2 is turned on as a fumigation gas. Switching to the return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the infrared gas sensor 70 through the air sampling pipe 23 for 20 seconds, and the measurement, storage, and display of the ethylene oxide concentration in the fumigation gas G are the same as before. To do. Thereby, the ethylene oxide concentration in the lower part in the fumigation warehouse C is measured. The fumigation gas G introduced into the infrared gas sensor 70 is returned into the fumigation chamber C as before.
After the concentration measurement (20 seconds after the solenoid valve SV3 is turned on), the solenoid valve SV3 of the air sampling tube 23 (CH.3) is closed (turned off).
(16) The solenoid valve SV3 is closed and the pump P is stopped for 2 seconds in step ST16.

(17) One (one cycle) measurement operation for the first measurement value is completed in the above steps ST8 to ST16. In step ST17, the measurement values obtained and stored in steps 9, 12, and 15 above, that is, the measurement of the upper (CH.1), middle (CH.2), and lower (CH.3) in the fumigation chamber C. Compare the values and determine whether the measurements are equal. Further, it is determined whether or not the measured value has reached a predetermined value (in this case, 1.5%).
CH. When the measured values 1 to 3 are not equal or have not reached the predetermined value, the above steps ST8 to 17 are repeated.
CH. When the measured values 1 to 3 are equal (measured values match) and reach a predetermined value, the process proceeds to the fumigation mode after step ST18 shown in FIG. Switching to the fumigation mode is performed by switching the mode switch 90. The determination in step ST17 and the switching operation of the mode selector switch 90 can be performed by an operator (manual) or can be performed by the control unit 60.
It should be noted that whether or not “measured values are identical (equal)” can be appropriately determined in relation to measurement accuracy. For example, when the present invention is carried out, and coincidence at the 0.1% level is desirable (required or sufficient) in relation to the measurement accuracy of the infrared gas sensor 70 and the catalytic combustion gas sensor DS, It may be determined as such, and if coincidence at the 0.01% level is desirable (required or sufficient), it may be determined as such.

(18) When the mode switch 90 is switched to the fumigation mode, the fumigation mode is entered at step ST18.
(19) In step ST19, in step ST17, CH. When it is determined that the measured values 1 to 3 are equal (measured values match) and have reached a predetermined value, the measured values are stored in the storage unit 80 as first measured values. In this embodiment, CH. 1 measurement value is stored as the first measurement value. Since the measured values of 1 to 3 coincide, CH. 2 or CH. 3 measurement values can also be stored as the first measurement value.

(20) In step ST20, a measurement operation for obtaining a gas concentration value (ethylene oxide concentration value) in the fumigation chamber C with time is started. First, zero adjustment is performed. That is, the pump P is operated, the air solenoid valve SV4-1 is turned on (opened), the first switching valve SV5 is placed on the infrared gas sensor 70 and the catalytic combustion gas sensor DS side, and the second changeover valve SV4-2. Is switched to the air exhaust side (see “NO” in FIG. 2), and air is introduced into the contact combustion gas sensor DS for 38 seconds. The air introduced into the contact combustion type gas sensor DS comes into contact with the contact combustion type gas sensor DS, and is then discharged into the atmosphere through the exhaust pipe 51, the junction pipe 53, and the second switching valve SV4-2.
The zero adjustment is performed by the control unit 60 setting the measured value to zero (that is, resetting the measured value) when the output of the catalytic combustion type gas sensor DS is stabilized during the air introduction.
After the zero adjustment (that is, after 38 seconds), the air solenoid valve SV4-1 is closed.

(21 ') The air solenoid valve SV4-1 is closed, and in step ST21', the solenoid valve SV1 of the sampling tube 21 (CH.1) is turned on (opened), and the second switching valve SV4-2 is turned on. By switching to the fumigation gas return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the contact combustion type gas sensor DS through the air sampling pipe 21 for 20 seconds, and the ethylene oxide concentration in the fumigation gas G is measured.
The fumigation gas G is also introduced into the infrared gas sensor 70, but after the first measurement value is obtained (after step ST20), measurement by the infrared gas sensor 70 is not performed (the mode changeover switch 90 is not fumigated). When in the mode, the signal from the infrared gas sensor 70 is ignored by the controller 60).
The measured value of ethylene oxide concentration by the catalytic combustion type gas sensor DS is obtained by the control unit 60 performing gas concentration calculation when the output of the catalytic combustion type gas sensor DS is stabilized during the introduction of the fumigation gas G.
In this step ST21 ′, the first measurement value obtained by the catalytic combustion type gas sensor DS as described above is set as the second measurement value, and a value obtained by dividing the first measurement value by the second measurement value is obtained. It is stored in the storage means 80 as a correction value.
If the first measured value obtained by the catalytic combustion type gas sensor DS as described above is 1.3%, for example, this measured value = 1.3% is set as the second measured value. 2. The measured value = 1.35486154, which is a value obtained by dividing the first measured value (for example, 1.5%) by 1.3%, is stored in the storage unit 80 as a correction value.
In step ST21 ′, 1.5% obtained by multiplying the first measured value by the correction value is displayed on the display unit (60) as a gas concentration value in the fumigation chamber C. Thereby, the ethylene oxide concentration (namely, sterilization / insecticidal ability) in the upper part in the fumigation warehouse C can be grasped.
The fumigation gas G introduced into the catalytic combustion type gas sensor DS is returned to the fumigation warehouse C (upper part of the fumigation warehouse C) as before.
After the concentration measurement (20 seconds after the electromagnetic valve SV1 is turned on), the electromagnetic valve SV1 of the sampling tube 21 (CH.1) is closed (turned OFF).

This step ST21 ′ is executed only at the first measurement by the catalytic combustion type gas sensor DS, and is not executed at the second and subsequent measurements. Step ST21 is executed during the second and subsequent measurements.
Step ST21 is different from step ST21 ′ in that the correction value is not calculated and therefore the correction value is not stored, and other points are not changed.

(22) The electromagnetic valve SV1 is closed and the pump P is stopped for 2 seconds in step ST22.

(23) The pump P is operated in step ST23, the air solenoid valve SV4-1 is turned on (opened), and the second valve SV4-2 is turned on the air exhaust side ("NO" in FIG. 2) as in step ST20. The air solenoid valve SV4-1 is closed after air is introduced into the contact combustion gas sensor DS for 38 seconds and zero adjustment is performed. The air introduced into the catalytic combustion gas sensor DS is discharged into the atmosphere through the exhaust pipe 51, the junction pipe 53, and the second switching valve SV4-2.

(24) The air solenoid valve SV4-1 is closed, and in step ST24, the solenoid valve SV2 of the sampling tube 22 (CH.2) is turned on (opened), and the second switching valve SV4-2 is turned on as a fumigation gas. Switching to the return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the contact combustion type gas sensor DS through the air sampling pipe 22 for 20 seconds, and the ethylene oxide concentration in the fumigation gas G is measured in the same manner as before.
Then, a value obtained by multiplying the measured value by the correction value (= 1.15346154) obtained in step ST21 ′ is calculated, and the value is displayed on the display unit (60) as a gas concentration value in the fumigation chamber C. Let Thereby, the ethylene oxide concentration (that is, sterilization / insecticidal ability) in the middle of the fumigation warehouse C can be grasped.
Note that the fumigation gas G introduced into the catalytic combustion type gas sensor DS is returned to the fumigation chamber C as before.
After the concentration measurement (20 seconds after the solenoid valve SV2 is turned on), the solenoid valve SV2 of the air sampling tube 22 (CH.2) is closed (turned off).
(25) The electromagnetic valve SV2 is closed and the pump P is stopped for 2 seconds in step ST13.

(26) In step ST26, the pump P is operated, and similarly to step ST20, the air solenoid valve SV4-1 is turned on (opened), and the second valve SV4-2 is turned on the air exhaust side ("NO" in FIG. 2). The air solenoid valve SV4-1 is closed after air is introduced into the contact combustion gas sensor DS for 38 seconds and zero adjustment is performed. Note that the air introduced into the catalytic combustion type gas sensor DS is discharged into the atmosphere.

(27) The air solenoid valve SV4-1 is closed, and in step ST27, the solenoid valve SV3 of the air sampling tube 23 (CH.3) is turned on (opened), and the second switching valve SV4-2 is turned on as fumigation gas. Switching to the return pipe 54 side, the fumigation gas G in the fumigation chamber C is introduced into the contact combustion gas sensor DS through the air sampling pipe 23 for 20 seconds, and the ethylene oxide concentration in the fumigation gas G is measured in the same manner as before.
Then, a value obtained by multiplying the measured value by the correction value (= 1.15346154) obtained in step ST21 ′ is calculated, and the value is displayed on the display unit (60) as a gas concentration value in the fumigation chamber C. Let Thereby, the ethylene oxide concentration (namely, sterilization / insecticidal ability) in the lower part in the fumigation warehouse C can be grasped.
Note that the fumigation gas G introduced into the catalytic combustion type gas sensor DS is returned to the fumigation chamber C as before.
After the concentration measurement (20 seconds after the solenoid valve SV3 is turned on), the solenoid valve SV3 of the air sampling tube 23 (CH.3) is closed (turned off).
(28) The electromagnetic valve SV3 is closed and the pump P is stopped for 2 seconds in step ST28.

  In the above steps ST20 to ST28, the one-time (one cycle) measurement operation using the catalytic combustion type gas sensor DS and the correction value is completed. Therefore, if this is left unattended, the contact combustion gas sensor DS comes into contact with the HFC 134a (catalyst poison) contained in the fumigation gas G, resulting in a decrease in sensitivity.

Therefore, in this embodiment, the scavenging operation is performed in the following step ST29. That is,
(29) In step ST29, the pump P is operated, the air solenoid valve SV4-1 is turned on (opened), and the second replacement valve SV4-2 is set to the air exhaust side (see “NO” in FIG. 2). After switching, air is introduced into the contact combustion gas sensor DS for 38 seconds to scavenge the gas chamber DS1 (see FIG. 5) of the contact combustion gas sensor DS and the gas chamber CS1 of the temperature compensation element CS. The air scavenged in the chamber is discharged to the atmosphere through the exhaust pipe 51, the junction pipe 53, and the second switching valve SV4-2.
After the scavenging operation, the pump P is stopped and the air solenoid valve SV4-1 is closed.

(30) Thereafter, in step ST30, the measurement results obtained in steps ST20 to ST28, that is, the gas concentration value corrected by the correction value and the measurement time are printed out by the printer.

(31) The standby state is entered in step ST31.
In the standby state, the measurement operation is stopped for the standby time set by the user.
For example, when the measurement operation is performed every 60 minutes, the standby time is set to a value (53 minutes) obtained by subtracting the time required for the measurement operation (for example, 7 minutes) from 60 minutes.

After the standby time has elapsed, gas replacement in the sampling tubes 21, 22, and 23 is performed in steps ST32 to ST37. Since this gas replacement operation is the same as the operation in steps ST2 to ST7 described above, description thereof is omitted.
By the operation of steps ST32 to 37, the gas in the sampling tubes 21, 22, and 23 is filled with the fumigation gas G after one cycle has elapsed (in the above example, after 60 minutes have elapsed).
Thereafter, the control after step ST20 is repeated. For example, if measurement for 24 hours is required, repeat until 24 hours have passed.
Thereafter, the exhaust stroke described above is performed, and the fumigation work is completed.

According to the fumigation gas concentration measuring method or the fumigation gas concentration measuring apparatus 1 as described above, the following effects can be obtained.
(A) After the fumigation gas G is put into the fumigation chamber C, the concentration of the sterilizing / insecticidal gas in the fumigation chamber C is first measured by the infrared gas sensor 70 to obtain the first measured value (see step ST9). ), At the initial stage where the relative concentration of the sterilizing / insecticidal gas to the diluting gas is high, the infrared gas sensor 70 can accurately obtain the first measured value. Since the infrared gas sensor is excellent in stability and reproducibility of gas sensitivity, the first measurement value can be obtained accurately every time no matter how many times fumigation work is performed.
Next, the contact combustion gas sensor 70 measures the concentration of the sterilizing / insecticidal gas in the fumigation chamber to obtain a second measured value, and obtains a corrected value obtained by dividing the first measured value by the second measured value. At this time, even if the sensitivity of the catalytic combustion gas sensor DS is lowered, the correction value itself can be obtained accurately because the first measurement value is obtained accurately (see step ST21 ′).
Thereafter, the concentration of the sterilizing / insecticidal gas in the fumigation chamber is measured intermittently and repeatedly with the contact combustion gas sensor DS, and the value obtained by multiplying the measured value by the correction value is determined as the gas in the fumigation chamber. Since the concentration value can be repeated intermittently, even if the sensitivity of the catalytic combustion type gas sensor has decreased due to long-term operation, it is possible to accurately measure the concentration of the sterilizing / insecticidal gas in the fumigation chamber over time. This is possible (see steps ST20-30).
Since the above correction is made every time fumigation is performed, accurate gas concentration measurement can be performed over a long period of time.
(B) Measurement by the infrared gas sensor 70 is performed at two or more locations in the vertical direction of the space inside the fumigation chamber (in this embodiment, three locations at the upper, middle, and lower locations). Since the value is the first measurement value (see step ST17), the first measurement value can be obtained more accurately, and thus a more accurate correction value can be obtained.
(C) Since the second measurement value itself is also multiplied by the correction value to obtain the gas concentration value in the fumigation chamber, the second measurement value, which is the first measurement value by the catalytic combustion type gas sensor DS, is used as the correction value. It can be used not only for obtaining but also for obtaining an initial gas concentration value based on the catalytic combustion type gas sensor DS.
(D) The introduction path for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor 70 and the introduction path for introducing the fumigation gas in the fumigation chamber into the contact combustion type gas sensor DS are shared by a common introduction path (fumigation gas introduction pipe). 20 and the valves SV1 to SV3, the filter 24, the valve 25, the pump P, and the valve SV5) interposed therein, the correction value can be obtained more accurately.
Assuming that the introduction path for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor 70 and the introduction path for introducing the fumigation gas in the fumigation chamber into the contact combustion type gas sensor DS are configured separately, the infrared gas sensor 70 may cause a large difference between the state of the fumigation gas introduced into 70 (for example, temperature and mixed state) and the state of the fumigation gas introduced into the catalytic combustion type gas sensor DS. The risk of not being able to be obtained increases.
On the other hand, according to this embodiment, the introduction path for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor 70 and the introduction path for introducing the fumigation gas in the fumigation chamber into the contact combustion type gas sensor DS are common. Therefore, even if there is a big difference between the state of the fumigation gas introduced into the infrared gas sensor 70 and the state of the fumigation gas introduced into the catalytic combustion type gas sensor DS The difference is significantly reduced. Therefore, the correction value can be obtained more accurately.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the gist of the present invention.
For example, the fumigation gas used is not limited to “exfume”, and has a sterilizing / insecticidal and flammable and infrared absorbing sterilizing / insecticing gas and an infrared absorbing property weaker than this sterilizing / insecticidal gas and The present invention can be applied when using a fumigation gas containing a diluent gas that acts as a catalyst poison.
In this embodiment, a value obtained by dividing the first measurement value by the second measurement value is obtained as a correction value, and a value obtained by multiplying the measurement value obtained by the catalytic combustion type gas sensor DS by the correction value is used as the gas concentration. Although the value obtained by dividing the second measured value by the first measured value is used as a correction value, the same result can be obtained by dividing the measured value obtained by the catalytic combustion type gas sensor DS by the corrected value. Thus, the two are substantially the same, so that claim 1 can be read as such.

C Fumigation chamber 1 Fumigation gas concentration measuring device M1 First measurement means M2 Second measurement means 20 Fumigation gas introduction pipe (introduction route)
60 Control Unit 70 Infrared Gas Sensor DS Contact Combustion Gas Sensor

Claims (5)

Fumigation objects are stored in a fumigation chamber, and sterilizing / insecticidal and flammable and infrared absorbing gas with sterilizing / insecticidal properties, and a weaker infrared absorbing property than this sterilizing / insecticidal gas and as a catalyst poison When fumigating the fumigation object by putting the fumigation gas containing the working dilution gas into the fumigation chamber,
After the fumigation gas is put in the fumigation chamber, first, the concentration of the sterilizing and insecticidal gas in the fumigation chamber is measured with an infrared gas sensor to obtain a first measured value, and then the fumigation chamber with a contact combustion type gas sensor. The concentration of the gas for sterilization / insecticide is measured to obtain a second measured value, and a correction value obtained by dividing the first measured value by the second measured value is obtained. The gas sensor can intermittently repeatedly measure the concentration of the sterilizing / insecticidal gas in the fumigation chamber, and multiply the measured value by the correction value to intermittently repeat the gas concentration value in the fumigation chamber. A method for measuring fumigation gas concentration.   The measurement by the infrared gas sensor is performed at two or more locations in the vertical direction of the space inside the fumigation chamber, and when the measured values coincide with each other, the measured value is set as the first measured value. The fumigation gas concentration measuring method according to 1.   3. The fumigation gas concentration measurement method according to claim 1, wherein the second measurement value itself is also multiplied by the correction value to obtain a gas concentration value in the fumigation chamber. A gas concentration measuring apparatus using the fumigation gas concentration measuring method according to claim 1,
First measuring means for obtaining the first measured value by introducing the fumigation gas in the fumigation chamber into an infrared gas sensor and measuring the concentration of the sterilizing / insecticidal gas in the fumigation gas;
Second measuring means for obtaining the second measured value by introducing the fumigation gas in the fumigation chamber into a contact combustion type gas sensor and measuring the concentration of the sterilizing / insecticidal gas in the fumigation gas;
The first measurement value is divided by the second measurement value to obtain the correction value, the correction value is stored, and the value obtained by multiplying the measurement value obtained by the second measurement means by the correction value is then stored in the fumigation chamber. A control unit for obtaining a gas concentration value in the inside,
A fumigation gas concentration measuring device comprising:   The introduction path for introducing the fumigation gas in the fumigation chamber into the infrared gas sensor and the introduction path for introducing the fumigation gas in the fumigation chamber into the catalytic combustion type gas sensor are configured by a common introduction path. The fumigation gas concentration measuring device according to claim 4.

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