JPH07128229A - Method and device for measuring organic solvent gas concentration, and dry cleaning machine - Google Patents

Abstract

PURPOSE:To provide an organic solvent gas concentration measuring device capable of measuring an organic solvent gas concentration with high responsiveness at low cost. CONSTITUTION:An organic solvent gas concentration measuring device has a projecting means 110 for emitting a wavelength light of ultraviolet ray area, a light receiving means 120 for receiving the light from the projecting means 11, a gas introducing means 130 having a gas passage 131 in the optical path 140 of the light receiving means 120, and a concentration arithmetic control (signal processing circuit) means 150 based on the known absorptive characteristic to a gas to be inspected, and the concentration of the gas to be inspected is measured by the concentration arithmetic control means 150. As the projecting means 110, a one suppressed in ozone generation is used, and heat insulating means for preventing the dewing in a sensing internal part are provided on the projecting means 110, the light receiving means 120, and the outer circumference of the gas passage 131.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, 1.1.1. Organic solvent gas concentration measuring method and device suitable for monitoring gas concentration of organic solvent used in various cleaning equipment using organic solvent such as trichloroethane, trichloroethylene, perchlorethylene, terpene (petroleum-based), and dry cleaning It is about machines.

[0002]

[Prior art]

(1) Gas Concentration Measurement In the past, as a method for measuring the gas concentration of an organic solvent, an infrared absorption type gas concentration sensor and a semiconductor type gas concentration sensor have been generally used and widely used. Normally, gas concentration measurement is performed by utilizing the fact that substances (gas, liquid, solid) all absorb light at a specific wavelength due to the bonding of atoms in the molecule. Absorption in the ultraviolet region is often due to changes in electron energy, and is used for analysis of those having unsaturated bonds or conjugated bonds by examining the ultraviolet absorption spectrum. Also, absorption in the infrared region occurs due to atomic vibrations in the molecule,
Appears in the μm range. It is used for qualitative analysis of functional groups and identification of compounds by investigating infrared absorption spectra.

Utilizing this property in gas concentration measurement, light of only a single wavelength that matches the absorption characteristics of the target gas is selected by a spectroscope (optical bandpass filter (BPF), diffraction grating, etc.) and irradiated. Or, the amount of absorption is measured by irradiating light through an interference system. Lambert-be absorption of light in both the ultraviolet and infrared regions
er) 's law is used to obtain the gas concentration.
In order to accurately measure the concentration of the target gas, coexisting gas,
In particular, absorption by nitrogen, oxygen, carbon dioxide, water vapor, etc. in the atmosphere is small, and it is necessary to measure the absorbance using a wavelength that is absorbed only by the target gas. Further, FIG. 3 shows the transmittance spectral characteristics of perchlorethylene from the ultraviolet light region to the infrared light region. As can be seen, the absorption of perchlorethylene by C-CL and C = C is 0.35 μm in the ultraviolet region.
In the following, it appears in the infrared light range of 10.6 to 13.5 μm, and when performing quantitative analysis of perchlorethylene, the absorption wavelength in the infrared light range is generally selected.

(2) Dry cleaning machine FIG. 10 shows a conventional cleaning and drying method using various organic solvents.
An outline is given using the system diagram of the dry cleaner shown in.
First, when the clothes 2 are put in through the door 1 and the door 1 is closed and the operation is started, the steps generally proceed in the following order. (1) The solvent 4 is pumped up from the solvent tank 3 via the valve 5 by the pump 6, and the required amount of the solvent 4 is sent to the processing tank 10 through the path including the valve 7 and the filter 8 or the path including the valve 9. (2) Slowly rotate the processing drum 11 to add the solvent 4 to the processing tank 1
0, the button trap 12, the valve 13, the pump 6, the valve 7, the filter 8, or the valve 9 is circulated to wash the clothes 2. (3) The treatment tank 10, the button trap 12, the valve 13, the pump 6, the valve 14, and the distiller 15 are drained through the path, and then the treatment drum 11 is rotated at a high speed to centrifuge the solvent 4 in the clothing 2. , Drain similarly. (4) The steps of (1) and (2) above are repeated.

(5) The treatment tank 10, the button trap 12, the valve 13 and the valve 5 are used to drain the solvent into the solvent tank 3, and then the treatment drum 11 is rotated at a high speed to centrifuge the solvent 4 in the garment 2. , Drain. (6) Slowly rotate the processing drum 11 again, the fan 16,
Air is circulated in the direction of arrow 20 between the recovery air duct 19 including the air cooler 17 and the air heater 18 and the processing tank 10 to dry the clothing 2. The solvent gas evaporated from the clothes 2 is condensed by the air cooler 17, enters the water separator 22 through the recovery path 21, and enters the clean tank 24 through the solvent pipe 23. (7) When the drying is completed, the dampers 25 and 26 open as shown by the broken line, fresh air is taken in from the damper 25, and the uncondensed solvent gas that cannot be collected by the air cooler 17 is exhausted from the damper 26, and the odor of the solvent in the clothing 2 Deodorize. (8) The solvent 4 that has entered the distiller 15 in the step (3) is evaporated and condensed and collected by the condenser 27, and the water separator 22,
The solvent enters the clean tank 24 through the solvent pipe 23 and returns from the partition plate 28 with overflow to the solvent tank 3. The water separated by the water separator 22 is discharged to the outside of the system through the water pipe 29. FIG. 11 shows an example in which the progress of the steps described above is shown for each solvent as time passes.

[0006]

However, the above-mentioned gas concentration measuring and dry cleaning machine has the following problems. (1) Gas concentration measurement (a) Quantitative analysis of perchlorethylene was carried out in the infrared region (10.6 ~
13.5 μm), the light in the wavelength band of 10.6 to 13.5 μm of the nichrome light source that is an infrared light source and the ceramic heater is weak, so to increase the sensitivity of PbS, MCT, thermopile, pyroelectric element, etc. that are light receivers. The chopper irradiates intermittent light to improve the resolution. However, with this method
It can measure only up to ppm. Moreover, this 10.6-13.5
The optical window material that transmits the wavelength band of μm is very expensive, and the film material for vapor deposition used for manufacturing BPF is also expensive. In addition, when perchlorethylene is measured using a semiconductor gas concentration sensor, the response time is only a few minutes, and the accuracy is not good, about ± 10% to ± 20%. Further, if the high-concentration gas is poisoned many times within a short period of time, the sensor deteriorates and the characteristics further deteriorate (FIGS. 6 and 7). (b) Although the BPF in the ultraviolet light region is relatively inexpensive compared to the infrared light region, the wavelength selection width (half-value width) has a width of about 3 to 5%. When measuring the absorbance at a wavelength other than the peak wavelength, it causes an error. (c) When a low-pressure mercury lamp is used as the ultraviolet light source, the wavelength of detected light cannot be arbitrarily selected because it is determined by the emission spectrum of mercury (Fig. 4). (d) When the gas concentration is measured by absorption measurement, the glass may cause an error in measuring the contamination. (e) When a low-pressure mercury lamp is used as the ultraviolet light source, its emission intensity changes depending on the ambient temperature (Fig. 5).

(2) Dry cleaning machine (f) Gas sampled from a dry cleaning machine, a metal cleaning machine, clothes after dry cleaning, etc. has a high temperature and humidity, and there is a possibility that dew condensation or gas may adhere in the sensing section. There is a possibility that this may cause a malfunction error. (g) At the end of the dry cleaner drying process, the gas concentration of perchlorethylene is about 20000 ppm, and the detection timing of the completion of the deodorizing process reaches from 5000 ppm to 100 ppm in a few minutes. It has not been possible to accurately determine the gas concentration measurement with such a large concentration change, and the drying process is performed by the sequence control set on the safe side (longer). Moreover, since the drying / deodorizing process is operated for a certain period of time, there is a risk of discharging high-concentration perchlorethylene gas due to insufficient drying / deodorizing. (h) Since the exhaust port concentration and workplace environment level are regulated to 50 ppm, perchlorethylene is usually adsorbed with activated carbon until the dry cleaner exhaust port is reached, and the perchlorethylene gas is adjusted to a concentration below the standard value. It is released outside,
At present, the gas concentration is regularly checked with a gas detector tube. However, there were problems such as fluctuations in gas concentration during operation, sudden abnormalities, or even if activated carbon was clogged and a rich gas was discharged from the exhaust port, it could not be detected immediately. (i) Some clothes may contain a large amount of perchlorethylene due to insufficient drying or insufficient deodorization when taken out after dry cleaning. It is important to check the gas concentration of perchlorethylene contained in the taken out clothing in order to judge the operating condition of the dry cleaner. For the above reasons, conventionally, there are few sensors that are inexpensive and can be accurately measured, and therefore, organic solvent gas concentration devices have not been widely used. Therefore, the present invention provides an organic gas concentration measuring device capable of measuring the gas concentration of an organic solvent with high response and at low cost, and further provides a dry cleaning machine using the same to solve the conventional problems. To do.

[0008]

Therefore, according to the present invention, the gas to be inspected is irradiated with the inspection light having a wavelength in the ultraviolet region, and the emission intensity and transmitted light intensity of the inspection light to the inspection gas are measured. Based on the gas absorption characteristics of the inspection light and the concentration of the inspection target gas measured in advance, the concentration of the inspection target gas is measured, and a light projecting means for irradiating the wavelength light in the ultraviolet light range, Light receiving means for receiving the light from the light projecting means, gas introducing means having a gas flow path portion in the optical path of the light projecting means and the light receiving means, and concentration calculation control based on a known light absorption characteristic for the gas to be inspected ( Signal processing circuit) means for measuring the concentration of the gas to be inspected introduced into the gas flow channel, and further as a dry cleaning machine equipped with the gas concentration device. It is an unit for determine.

[0009]

In the present invention, an ozone-less low-pressure mercury lamp is used as the light source of the gas concentration measuring device, and the BPF is omitted to achieve cost reduction. A photodiode (photomultiplier tube (photomultiplier)) is used as the light receiver. Yes] is used to increase sensitivity, resolution, and responsiveness. Fused quartz is used as the optical window material to reduce the cost. When a low-pressure mercury lamp with a phosphor is used, the emission wavelength 254 μm of the low-pressure mercury lamp can be converted to another wavelength by the phosphor. Furthermore, depending on the emission wavelength, it is possible to use a low-cost optical window material such as BK7 or crown glass, which can be dealt with without making a large change in the device configuration. By keeping the temperature of the entire sensing unit at 50 ° C, the emission intensity of the light source is stabilized, the adhesion of water vapor inside the sensing unit is suppressed, and according to the sensing cycle, outside air is put into the sensor when it is not sensed This has the effect of accelerating the time for cleaning the adhered gas and water vapor.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings.
It First, the organic solvent gas concentration measuring device will be described.
As shown in FIG. 1, the detection unit 100 of the gas concentration measuring device is arranged as follows.
The light means 110, the light receiving means 120, and the gas introducing means 130
Consists of In addition, the light receiving means 120 is a light receiver 120.
a, 120b, 120c are collectively referred to. Projecting means 11
0 uses an ozoneless low-pressure mercury lamp as the light source 111
(This is Vycor glass in the glass part of the low pressure mercury lamp.
Is a mercury lamp that suppresses the reflection of 185 nm light using
is there). The light receiving means 120 refers to the light emission intensity of the light source.
Therefore, a reference light receiver 120c is installed. This is one
Used when using the optical path type. The light from the low-pressure mercury lamp 111 is
Enter into the arm portions 134 and 135 and the bottom portion 136 of the flow passage 131.
There are two windows 113a and 113b for shooting,
Filters 112a and 11 using fused silica glass for the windows
2b is provided to reduce the cost and the light of 185nm. Gas flow
The path 131 has a U-shaped flow path, and is output from the window 112a.
The light path length L ₁Light receiver 1 with an interval of (140a)
The light received by 20a and similarly emitted from the window 112b is in the optical path.
Long L₂The light receiver 120b receives the light at an interval of (140b).
Be illuminated. Then, the light projecting means 110 and the light receiving means 12
0, the entire gas flow path 131 is a heater as shown in FIG.
-161 and wound by the temperature controller 162.
The temperature is regulated.

Next, the structure of the gas concentration measuring device 200 is shown in FIG.
3, the device is a three-way valve 201 for switching between gas and outside air (clean air), a membrane Teflon mesh filter 204 for removing dust, water droplets, etc. from the sucked air,
A heater 161 that keeps the temperature of the entire sensing unit and a temperature keeping unit 160 that adjusts the temperature inside the heater, a preamplifier unit 151 that converts the current from the light receivers 120a, 120b, and 120c into a voltage, and this signal is digital. An A / D converter unit 152 for conversion, a sampling pump 202 for sucking gas, a regulator 203 with a flow meter for adjusting the intake air flow rate,
The signal processing circuit 153 is composed of a circuit 153a that takes in an optical signal from the A / D converter unit 152 and calculates the density, and a control circuit 153b that controls switching of the three-way valve 201. The preamplifier section 151, the A / D converter section 152, and the signal processing circuit 153 constitute the density calculation control means 150. Now, as a pretreatment, all the power supplies are turned on, the sampling pump 202 is operated, a predetermined temperature is set for the temperature controller 162, and the temperature is stabilized (the warm-up time of the light source and others is taken into consideration. Wait about 30 minutes). Here, in order to prevent dew condensation inside the sensing unit, the entire sensing unit is set to about 50%, which is almost the same as the gas temperature inside the dry cleaning machine processing tank.
℃. The regulator 203 with a flow meter adjusts the intake air flow rate to a predetermined flow rate. 3 way valve 2 at this time
01 is on the outside air side.

Next, the detection routine will be explained. When the gas concentration is not detected, the three-way valve 2 is used so that the outside air can be sucked in.
01 is switched to introduce the outside air into the gas introducing means 130. The three-way valve 201 is switched to the machine side at the gas detection timing according to the machine operation cycle. The gas is carried into the U-shaped flow path 131, at which time the amount of light absorbed by the optical path length L _{1 is} measured by the light receiver 120a, and the amount of light absorbed by the optical path length L _{2 is} measured by the light receiver 120b. . These signals are subjected to voltage conversion by the preamplifier section 151, digitized by the A / D converter section 152, and then taken into the signal processing circuit 153.

Here, a gas concentration measuring method using the two-optical path method for improving the accuracy of the measured value will be described. In this measurement, the measured value is corrected by measuring the absorbance using two different optical path lengths. Here, a: absorption coefficient of gas (1 / ppm / mm) C: gas concentration (ppm) K ₁₁ , K ₁₂ : constants determined by light source and optical system in optical path 1 and optical path 2 and dirt L _1, L ₂ : optical path 1, the optical path length of the optical path 2 (L ₂ > L ₁ ) I _1, I ₂ : is the intensity of the light after passing through the optical paths of the optical path 1 and the optical path 2, and for the convenience of the measured value, the absorption coefficient a of the gas is Was used. Generally, 1 / (mpl / l) / cm 2 is used. Assuming that the absorption of light follows Lambart-beer's law,

[ ^Equation 1] I ₀₁ = L ₀ · K ₁₁ · e ^-acL1 ... (1)

[ ^Equation 2] I ₀₂ = L ₀ · K ₁₂ · e ^−acL2 (2) Here, by transforming the equations (1) and (2) to obtain the transmittance ratio Rp,

[Equation 3] Therefore, assuming that K ₁₁ and K ₁₂ are constantly or uniformly soiled, K ₁₁ / K ₁₂ can be treated as a constant device constant. Therefore, the concentration C is

[Equation 4] Becomes In fact, when the gas concentration is extremely high or low, a measurement error is likely to occur. In such a case, the gas concentration is calculated using equations (1) and (2) by one-path measurement. That is, when the gas concentration is low, the long cell length L
Measurement is performed on the ₂ side, and when the gas concentration is high, measurement is performed on the short cell length L ₁ side. By doing so, the gas concentration measurement range can be expanded, and the intermediate concentration range is measured using the above equation (4).

Many organic solvents have a double bond or an aromatic cyclic group, and most of them show absorption characteristics in the ultraviolet region. For example, the absorption characteristics of perchlorethylene are shown in FIG. Therefore, in the above organic solvent, the ultraviolet light range (200-400 nm)
Since there is absorption by C-CL and C = C in, the absorbance is measured using the absorption of ultraviolet light. For the light source of the projector in this device, an ozone-less low-pressure mercury lamp (a material of a low-pressure mercury lamp that cannot transmit a wavelength of 200 nm or less, such as Vycor, synthetic quartz, or fused quartz) is used. It is a lamp that suppresses the emission of 185 nm light). The low-pressure mercury lamp is an ultraviolet light source having a strong light at 254 nm as shown in FIG. 4, and the emission intensity does not change much at about 50 ° C. even if the temperature changes as shown in FIG.
The window on the light source side is made of a material such as fused silica that cannot transmit a wavelength of 200 nm or less. Furthermore, an ultraviolet light transmission filter (350 nm or less) or a bandpass filter (BP
If F) is used, higher accuracy can be maintained. In addition, a low pressure mercury lamp in which a phosphor is applied to the inner wall of the glass is used. Furthermore, in order to deal with dirt on the window and deterioration of the light source, a two-optical path system is adopted. The gas sampling system is an air circuit in which the sample side and the outside air side are arbitrarily switched by a three-way valve and can be sucked in, and a membrane Teflon mesh filter is used to remove dust generated from clothes and the like.

Next, a measurement example using an optical path length L ₁ = 10 mm, an optical path length L ₂ = 100 mm, a low pressure mercury lamp 100 mW, and a photodiode will be described. Signal processing circuit 15
In step 3, first, it is determined whether the transmittance on the optical path length L ₁ side is 0.01 or less. If the transmittance is 0.01 or less, the gas concentration is determined by the transmittance on the optical path length L ₁ side according to the following equation.

[Equation 5] If the transmittance is 0.01 or more, the gas concentration is determined by the following equation from the two signals.

[Equation 6] If the transmittance is 0.99 or more, the gas concentration is determined by the transmittance on the optical path length L ₂ side according to the following equation.

[Equation 7] The threshold value for determining the transmittance differs depending on the system.

Next, the relationship between the gas concentration measuring device 200 and the dry cleaning machine will be described. FIG. 8 shows a sectional view of a main part of a dry cleaning machine using the gas concentration meter of the present invention, and FIG. 9 is a process explanatory view. First, steps (1) to (7) described above are performed here. Until the deodorizing step, the three-way valve 101 of the gas concentration measuring device 200 is placed on the outside air side and the outside air is introduced. Next, after a certain period of time from the start of the deodorizing process (this time depends on the capacity of the machine),
The 3-way valve 101 is switched to the machine side. Then, the organic solvent gas concentration is measured according to the gas concentration measuring step. At this time, the deodorizing process is continued until the gas concentration falls below a certain concentration, and until then the door is locked so that it does not open. When the gas concentration falls below a certain concentration, the door lock is unlocked and clothes can be taken out. Like

[0017]

As described above in detail, according to the present invention, by using the gas concentration measuring device, the gas concentration of the organic solvent can be measured with high response (1 second or less) and at low cost up to several ppm. . Further, by using the gas concentration measuring device of the present invention, even if problems such as insufficient drying of clothes or insufficient deodorization occur, it is possible to open the door and take out clothes while monitoring the gas concentration. It can contribute to the reduction of operating time and increase efficiency. In addition, it is possible to monitor changes in gas concentration during operation, check the adsorption capacity of activated carbon over, and check the gas concentration of perchlorethylene contained in the taken out clothing to check the operating condition of the dry cleaner. You can judge.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a detection unit in an organic solvent gas concentration measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a gas concentration measuring device according to an embodiment of the present invention.

FIG. 3 is a transmittance spectrum diagram of perchlorethylene from an ultraviolet light region to an infrared light region.

FIG. 4 is an emission spectrum diagram of a low-pressure mercury lamp.

FIG. 5 is a diagram showing the relationship between the emission intensity and the temperature of a low-pressure mercury lamp.

FIG. 6 is a sensitivity characteristic diagram of a semiconductor gas sensor with respect to perchlorethylene.

FIG. 7 is a response diagram of a semiconductor gas sensor to perchlorethylene.

FIG. 8 is a system diagram of a dry cleaning machine using a gas concentration meter according to the present invention.

FIG. 9 is a process explanatory view of a dry cleaning machine using the gas concentration meter according to the present invention.

FIG. 10 is a system diagram of a conventional dry cleaning machine.

FIG. 11 is a process explanatory view of a conventional dry cleaning machine.

[Explanation of symbols]

 2 Clothing 3, 3a Solvent storage tank 4, 4a Solvent 5, 5a Special valve 8, 8a Filter 10 Processing tank 11 Processing drum 15 Distiller 17 Air cooler 23, 23a, 31 Solvent piping 30 Solvent separator 32, 41 Check valve 33 , 33a Three-way switching valve 100 Detection unit 110 Light projecting means (light source section) 111 Low-pressure mercury lamp 112, 112a, 112b Optical filter 113 General name of windows 113a, 113b, 113c Window 120 Light receiving means 120a, 120b, 120c Light receiving means (light receiver) ) 130 gas introduction means 131 gas flow path (U-shaped) 132 gas inlet 133 gas outlet 134.135 arms 136 bottom 140 general term of optical path 140a, 140b optical path 150 concentration calculation control means 151 preamplifier section 152 A / D converter 153 Signal processing circuit 53a density arithmetic circuit 153b control circuit 160 temperature adjusting means 161 heater 162 temperature controller 200 gas concentration measuring apparatus 201 three-way valve 202 sampling pump 203 flow meter with regulator 204 membrane Teflon mesh filter

Continued Front Page (72) Inventor Haruo Hagiwara 1 Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya City Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works

Claims (14)

[Claims] 1. The concentration of the gas to be inspected, which is measured in advance, by irradiating the gas to be inspected with an inspection light having a wavelength in the ultraviolet region and measuring the emission intensity and the transmitted light intensity of the inspection light to the gas to be inspected. And a method for measuring the concentration of an organic solvent gas, which comprises measuring the concentration of the gas to be inspected based on the gas absorption characteristics of the inspection light. 2. A gas having a light projecting means for irradiating light having a wavelength in the ultraviolet range, a light receiving means for receiving light from the light projecting means, and a gas flow path part in an optical path of the light projecting means and the light receiving means. Organic solvent gas concentration measurement characterized by measuring the concentration of the gas to be inspected introduced into the gas flow path, comprising an introducing means and a concentration calculation control (signal processing circuit) means based on a known absorption characteristic for the gas to be inspected. apparatus. 3. The light projecting means comprises a low-pressure mercury lamp and an optical filter, the low-pressure mercury lamp is an ozoneless type, and the optical filter is one capable of blocking light of at least 200 nm or less to suppress ozone generation. The organic solvent gas concentration measuring device according to claim 2. 4. A heat insulating means comprising a heater and a temperature adjusting means for controlling the temperature inside the heater is provided on the outer periphery of the light projecting means, the light receiving means, and the gas flow path. Item 3. The organic solvent gas concentration measuring device according to item 3. 5. The organic solvent gas concentration measuring device according to claim 4, wherein the gas flow path forms a substantially U-shaped passage having two arms and a bottom from an inlet to an outlet. 6. The light receiving means is constituted by two light receiving means installed so as to have at least two optical path lengths different from the light projecting means. Alternatively, the organic solvent gas concentration measuring device according to claim 5. 7. The organic solvent gas concentration measuring device according to claim 6, wherein the outputs of the two different optical path lengths can be selectively used according to the gas concentration. 8. The light receiving means is one arm of a U-shaped flow path.
Optical path L in the diameter direction of ₁Provided at positions separated by only
Is the optical path L in the axial direction of the bottom of the U-shaped channel₂Only separated position
7. The organic solvent gas according to claim 6, characterized in that
Concentration measuring device. 9. The gas flow path section is provided with a three-way valve at an inlet and an outlet so that a gas to be measured can be confined in a sensing section by a signal from a concentration calculating means. The organic solvent gas concentration measuring device according to any one of claims 2 to 8. 10. The inlet side of the gas flow path portion can be switched between the outside air (clean air) side and the measurement target gas side by a signal from the concentration calculation control means via a three-way valve. The organic solvent gas concentration measuring device according to any one of claims 2 to 9. 11. The ultraviolet light projecting means comprises a low-pressure mercury lamp and an optical filter, and the low-pressure mercury lamp comprises a glass inner wall coated with a phosphor. Organic solvent gas concentration measuring device. 12. A dry cleaning machine for cleaning clothes and the like using an organic solvent, wherein the processing tank portion of the machine is equipped with the organic solvent gas concentration measuring device according to claim 2. Dry cleaning machine. 13. A dry cleaning machine for cleaning clothes and the like using an organic solvent, wherein the exhaust port of the machine is equipped with the organic solvent gas concentration measuring device according to any one of claims 2 to 11. Dry cleaning machine. 14. The dry cleaning machine has a sampling tube or a hot box, and the residual organic solvent gas concentration in the clothes washed by the dry cleaning machine is measured in the sampling tube or the hot box. Alternatively, the dry cleaning machine according to claim 13.