JP2001242057A - Simple small gas or airborne particulate detector - Google Patents

Abstract

(57) [Summary] A simple small gas or airborne particulate detection device of the present invention can continuously measure and monitor harmful gases in the measurement target environment, airborne particulates, and the like. Provided is a simple small gas or airborne particulate detection device. (A) A means for adsorbing only a gas to be detected or airborne particulates to a quartz oscillator, and (B) A quartz oscillator to which a gas to be detected or airborne particulates is adsorbed oscillates and its frequency change is measured. Means for displaying
The means of (B) includes: (C) means for oscillating a quartz oscillator that adsorbs a gas to be detected or airborne fine particles in a housing; and (D) means for oscillating a frequency change caused by oscillation of the quartz oscillator. Means for measuring and (E) means for displaying the frequency change are incorporated and integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small gas or airborne fine particle capable of quickly and easily detecting the gas to be detected or airborne fine particles from a gas containing the gas to be detected or airborne fine particles at a site or the like. It relates to a detection device.

[Prior art]

[0002] Modern people use various chemical substances to carry out social life. Chemicals have been developed with the aim of helping humans in their own lives. However, while their benefits are high, there are also many substances that have a negative effect on human health and ecosystems. In addition to substances synthesized and produced by human beings, there are also chemical substances that are unintentionally generated by combustion or the like, and dioxins that have attracted great social attention are representative of them. Conventionally, various types of gas or airborne particulate sensors have been known, but since the measurement sensitivity is not so high, it is difficult to specify the components of the target gas depending on the type of the target gas. If the concentration of airborne particulates is low,
There is a problem that it is difficult to measure the amount accurately, and even if it can be measured, it takes too much time. Further, as shown in FIG. 2, the conventional gas or airborne particulate sensor generally has a large size and is made up of many members, and therefore has difficulty in transportability and assemblability to a narrow work site. Lack of responsiveness in an emergency, simple on-site,
It has been difficult to quickly and continuously measure and monitor harmful gases.

[0003]

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned disadvantages of the prior art, and accurately and accurately detects a gas component such as a harmful gas in the environment to be measured even if the gas component is small in the environment. Simple small gas or air that can be easily detected, and is small in size and easy to handle and operate. It is an object of the present invention to provide an apparatus for detecting suspended particles in air.

[0004]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a gas containing a gas to be detected or fine particles suspended in the air is converted into a gas or fine particles suspended in the air. A device (oscillation circuit) that oscillates a quartz oscillator that adsorbs a gas to be detected or airborne particles in the air while bringing an adsorbing film into contact with the quartz oscillator having a surface, and a frequency change caused by the oscillation of the quartz oscillator It has been found that it is effective to solve the above-mentioned problem by incorporating a measuring device (frequency meter) and a display device (display unit) of the measured frequency into a housing and integrating them, and have completed the present invention. Was. That is, according to the present invention, first, (A) a quartz crystal having on its surface a film having a property of adsorbing a gas to be detected or a gas containing airborne fine particles to the detection gas or airborne fine particles. Means for adsorbing only the gas to be detected or airborne particles to the quartz oscillator by contacting the oscillator is (B) oscillating the crystal oscillator to which the gas to be detected or airborne particles are adsorbed and measuring the frequency change. And means for oscillating the quartz oscillator adsorbing the gas to be detected or airborne particulates described in (B) above, and measuring and displaying a change in the frequency of the quartz oscillator. (C) means for oscillating a quartz oscillator adsorbing a gas to be detected or airborne fine particles, (D) means for measuring a change in oscillation frequency generated by oscillation of the quartz oscillator, and (E) Simple small gas or airborne particle detector system, characterized in that those means for displaying the frequency change is integrated embedded is provided. Secondly, in the first device, a simple small-sized gas or airborne particulate detection device having a portable shape is provided. Thirdly, there is provided a simple and small gas or airborne particulate detection device characterized in that a quartz oscillator having a high fundamental frequency is used in the first or second device. Fourthly, there is provided a simple small gas or airborne particulate detection device characterized in that in any one of the first to third devices, an overtone of a quartz oscillator is used. Fifth, there is provided a simple detection method of a detection target gas or airborne particulates using any of the first to fourth simple small gas or airborne particulate detection devices.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A simple and small detecting device of the present invention will be described with reference to FIG. FIG.
In (A), the gas to be detected or the gas containing fine particles suspended in the air is brought into contact with a quartz oscillator having a film on its surface which has a coating property for the gas to be detected or the fine particles suspended in the atmosphere, and Or means for adsorbing only airborne particulates to a quartz oscillator (quartz oscillator),
(B) is a means (detector main body) for oscillating a quartz oscillator adsorbing a gas to be detected or airborne fine particles, and measuring and displaying a change in the oscillating frequency. (C) means (oscillation circuit) for oscillating a quartz oscillator adsorbing a gas to be detected or airborne fine particles;
(D) A means (frequency meter) for measuring a change in the oscillation frequency generated by the oscillation of the quartz oscillator and (E) a means for displaying the change in the frequency (display for displaying the oscillation frequency) are integrated and integrated. In FIG. 1, the unit is mm.

More specifically, means (B) for oscillating a quartz oscillator adsorbing a gas to be detected or airborne fine particles, and measuring and displaying a change in oscillation frequency (detector body)
(C) Oscillation circuit of crystal oscillator devised to oscillate even at high frequency in metal housing (D) Akizuki Tsusho's frequency measurement kit (PIC Kitv
2.00) and (E) a liquid crystal display unit and the like are incorporated and appropriately integrated by a coupling means. Of course, (C) and (D) can be further integrated and miniaturized by designing and manufacturing as one IC with reference to the present invention.
It can be integrated in a case made of metal, resin, or ceramics, including miniaturization of (E).

Although there is no particular limitation on the crystal unit used in the present invention, the higher the fundamental frequency, the larger the oscillation frequency response and the higher the sensitivity.
Preferably 50 MHz or more, more preferably 100 MHz
It is desirable to use the above. In order to further develop the high sensitivity characteristic, a so-called harmonic (N) (order of harmonic, N = 3, 5, 7, 9,
11, 13, 15, 17, 19, 21...). For example, the third harmonic mode (N =
3) The fifth harmonic mode (N = 5) is preferably used.

Further, as the film formed on the surface of the quartz oscillator, any film can be used as long as it has a property of adsorbing to the gas to be detected. Examples of such a film forming method include coating on a quartz oscillator by various methods (for example, casting method, LB method, dip coating method, plasma polymerization method, vacuum deposition method, coating by laser ablation, radical polymerization, ionization, and the like). Various polymers synthesized by using a direct polymerization method by polymerization or polycondensation) or directly synthesized on a quartz crystal by a plasma polymerization method or the like and its raw material monomers are used. Specific examples of the coating material include polystyrene, polybutadiene, polyethylene, polypropylene, polyisobutylene, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polypropyl methacrylate, polyacrylic acid, and polyacrylamide. , Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, natural rubber, polychloroprene, beech-N
(Butadiene-acrylonitrile 75/25), polyoxyethylene, polymaleic anhydride, polyvinylidene fluoride, polyacrylonitrile, polyvinyl acetate, polyethylene terephthalate, polyamide (nylon 6, nylon 66, nylon, etc.), polydimethylsiloxane, methylcellulose, Cellulose acetate, nitrocellulose, styrene-acrylonitrile copolymer, polyphenylene ether, polycarbonate, squalane, epoxy resins, copolymer resins, etc. are used, further, metals such as palladium and rhodium, optically active resins, phthalocyanines,
Porphyrins, calixarenes, crown ethers, cyclophanes, catenanes, cyclic peptides,
Examples include antibodies, lectins, avidin, biotin, sugars, organic metals, pigments, coal, activated carbon, clays, ceramics, silica gel, activated alumina, porous polymer beads, zeolites, fullerenes, carbon nanotubes, and the like. A conventionally known stationary phase liquid of a column packing for gas chromatography can also be used.

In order to form such a film-forming material on the surface of a quartz oscillator, a conventionally known film-forming method such as a plasma polymerization method or a coating method may be appropriately used. In addition,
Since the surface of the crystal unit may have contaminants derived from the environment attached thereto, it is desirable to clean the surface of the crystal unit in advance by an appropriate means such as plasma treatment before forming a film.

Silver or gold is preferable as the electrode material of the crystal unit, and silver is good in terms of frequency response and inexpensiveness, but it is resistant to oxidation of the electrode surface during storage in air before use. To gold is more preferred.

There are two typical examples of the simple and compact gas detector of the present invention. One of them is to use an LED display for the measurement frequency display section.
V AC adapter drive. The other one uses a liquid crystal display for the measurement frequency display unit, and uses a small amount of power and is driven by a dry battery (one of 9V and 006P is used). The dry batteries can be replaced with rechargeable batteries of the same capacity.

As shown in FIG. 2, a conventional device for detecting gas or airborne particulates includes (d) a device for oscillating a quartz oscillator (oscillation circuit), and (e) a frequency generated by oscillation of the quartz oscillator. A measuring device (frequency meter), a display device of the measured frequency (display unit), (c) a stabilized power supply,
(F) Since various measuring devices such as a computer are arranged separately and many connecting devices such as a BNC cable and a GP-IB cable for connecting the measuring devices are required, the device becomes large-scale, and the Although there was a disadvantage that it could not be installed, in the present invention, (B)
Means for oscillating a quartz oscillator to which a gas to be detected or airborne particles in the atmosphere are attached, and measuring and displaying a change in frequency thereof is provided by (C) a crystal in which the gas to be detected or airborne particles in the air is attached to the housing. Since the means for oscillating the vibrator, the means for (D) measuring the frequency change generated by the oscillation of the crystal oscillator, and the means for displaying the measured frequency (E) are integrated and integrated, the BNC cable, G
Eliminates the need for connecting devices such as P-IB cables and the size of the device is 11cm (length) x 13cm (width) x 3c
m (thickness) and a total weight of about 0.3 kg (including a 9 V battery) can be significantly reduced in size and weight compared to conventional products, and it is easy to move and carry. Can be easily installed in a small environment.

Further, the conventional apparatus for detecting gaseous or airborne particulate matter requires skill in connection, handling, and the like. However, the apparatus of the present invention can perform the connection and measurement operations with a very simple operation. It can be easily used even by non-experts.

The gases to be detected in the present invention include semiconductor processing gases, poison gases, alcohols, ethers, ketones, aldehydes, aromatics, halogenated aromatics, aliphatic halogen compounds, and organic phosphorus compounds. , Dioxins, endocrine disruptors, pesticides, pesticides, etc., or airborne fine particles, and specifically, chlorine, bromine, arsenic, cadmium, nickel, N
H3, PCl3, PCl5, HCl, HF, F2, SO
2, NO2, SF6, CF4, C2F6, SiH4, P
H3, WF6, CO, CO2, H2O, phenol, hydrogen sulfide, ipert, phosgene, sarin, hydrocyanic acid, chloropicrin, chloroacetophenone, chlorobenzylidene malononitrile, 3-quinuclidinyl benzylate, lysergic acid diethylamide, VX, tabun, Soman, p
-Dichlorobenzene, formaldehyde, tetrahydrofuran, ethyl acetate, butyl acetate, isoamyl acetate, morpholine, methylamine, ethylamine, triethylamine, mercaptan, dimethylformamide, chlorophenol, dichlorobenzene, dioxane, dimethylsulfide, aniline, nitromethane, pyridine, acetic acid,
Formic acid, α-pinene, camphor, menthol, methanol, ethanol, methyl ethyl ether, methyl ethyl ketone, diethyl ether, acetone, chloroform,
Hexane, pentane, trichlorofluoromethane, dichlorodifluoromethane, trichlorotrifluoroethane, carbon tetrachloride, tetrachloroethylene, trichloroethylene, 1,2-dichloroethane, 1,2-dichloropropane, acrylonitrile, acetonitrile, isobutylnitrile, benzene, toluene, ethylbenzene , Xylene (o-, m-, p-), chlorobenzene, nitrobenzene, dichloromethane, vinyl chloride, methyl chloride, 1,
1,1-trichloroethane, chlorodibromoethane, bromoform, 1,1-dichloroethane, 1,2-dichloroethylene (trans-, cis-), methyl bromide, bromoethane, polychlorinated biphenyl, polychlorinated naphthalene, chlordane, dieldrin , Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran, petroleum ether, floating particulates in diesel vehicle waste gas, floating particulates generated from garbage incineration plants and factories, floating particulate asbestos generated from demolition work sites, and the like. You.

In order to detect the gas to be detected or the airborne particulates from the gas to be detected or the gas containing airborne particulates in the apparatus of the present invention, the gas to be detected or the gas containing the airborne particulates must be detected. Alternatively, by contacting a quartz oscillator with a film that has an absorptive property on airborne particulates on the surface, only the gas to be detected or airborne particulates is adsorbed to the crystal oscillator, and the oscillation frequency change due to the adsorption is detected. You can read it on the main body. The amount of the substance to be detected can be calculated by inserting the frequency response detected by the object to be measured into a calibration curve calibrated based on the amount of the substance to be detected previously prepared and the frequency response of the sensor. A quartz oscillator having a coating on its surface that has absorptivity to the gas to be detected or airborne fine particles once used for sample measurement may be disposable because it is inexpensive. The sensor unit can be used repeatedly as long as it can remove adsorbed gas or airborne fine particles by blowing an inert gas or the like. The desorption of the adsorbate can be easily confirmed by determining whether the oscillation frequency before the sample measurement is exhibited.

[0016]

Now, the present invention will be described in further detail with reference to embodiments. In addition, the following measurements were performed using the small simple gas or airborne particulate matter detection apparatus shown in FIG.

Example 1 Helium sputter was performed on six 9 MHz (N = 1) quartz crystal units using a plasma polymerization apparatus, the resonance frequency was measured with an impedance analyzer, and again for 4 minutes using the plasma polymerization apparatus. A film of styrene was applied. Using this quartz oscillator, measurement was performed for five minutes with respect to four kinds of gases of chloroform, diethyl ether, acetone, and ethanol (the injection amount was 20,000 ppm each). The result is shown in FIG.
As is clear from FIG. 3, this apparatus shows high detection sensitivity in the order of chloroform, diethyl ether, acetone, and ethanol among the four gases, and the higher the detection sensitivity, the more the detection sensitivity before the gas is injected. It can be seen that it takes time to return to the frequency.

Embodiment 2 In Embodiment 1, a 9 MHz (N = 1) crystal oscillator is replaced with a 50 MHz (N =
The detection sensitivities of four types of gases were measured using a 50 MHz quartz oscillator having a styrene film attached thereto in the same manner as in Example 1 except that the quartz oscillator of 1) was used. FIG. 4 shows the results. It can be seen that this device has the same sensitivity characteristics as the first embodiment, and has 26 times higher response sensitivity than the one using the 9 MHz quartz oscillator of the first embodiment.

Embodiment 3 In the first embodiment, a 9 MHz (N = 1) crystal oscillator is replaced with a 100 MHz (N
= 3) The detection sensitivity for four types of gases was measured using a 100 MHz (N = 3) crystal resonator coated with styrene in the same manner as in Example 1 except that the crystal resonator of (3) was used. . The result is shown in FIG. This device has sensitivity characteristics similar to those of the first embodiment, and shows that the response sensitivity is 42 times higher than that of the first embodiment using the 9 MHz (N = 1) crystal resonator.

Example 4 A 100 MHz (N = 5) styrene film was applied in the same manner as in Example 1 except that the 9 MHz quartz oscillator was replaced with a 100 MHz (N = 5) quartz oscillator. 4) using a quartz oscillator
The measurement of the detection sensitivity for each type of gas was performed. FIG. 6 shows the result. It can be seen that this device has the same sensitivity characteristics as the first embodiment, and has a 22 times higher response sensitivity than the one using the 9 MHz quartz oscillator of the first embodiment.

Example 5 One of the 9 MHz (N = 1) crystal resonators coated with a plasma polymerized film and exhibiting a frequency change closest to the theoretical value is one of the crystal resonators.
One, and the concentration of acetone gas to be injected is 10,000 ppm, 20
The detection sensitivity for each of 000 ppm and 30,000 ppm was examined.
FIG. 7 shows the measurement results. From this figure, it can be seen that this device maintains high detection sensitivity even when the target gas concentration changes.

Example 6 The detection sensitivity to the concentration of the acetone gas to be injected was examined in the same manner as in Example 5, except that the quartz oscillator was replaced with a 50 MHz (N = 1) quartz oscillator. This measurement result is shown in FIG.
Shown in From this result, it can be seen from this figure that the device of the present invention maintains the detection sensitivity as the concentration of the target gas changes, as it becomes higher. The device using a 50MHz (N = 1) crystal oscillator is 9
It can be seen that the sensitivity is 35 times higher than that using the MHz (N = 1) crystal resonator.

Example 7 The detection sensitivity to the concentration of the acetone gas to be injected was examined in the same manner as in Example 5, except that the crystal oscillator was replaced with a 100 MHz (N = 3) crystal oscillator. FIG. 9 shows the measurement results. From this result, it can be seen from this figure that the device of the present invention maintains the detection sensitivity as the concentration of the target gas changes, as it becomes higher. Also, it can be seen that a device using a 100 MHz (N = 3) crystal resonator has 47 times the sensitivity as compared with a device using a 9 MHz (N = 1) crystal resonator.

Example 8 The detection sensitivity to the concentration of the acetone gas to be injected was examined in the same manner as in Example 5, except that the crystal oscillator was replaced with a 100 MHz (N = 5) crystal oscillator. FIG. 10 shows the measurement results. From this figure, it can be seen that the apparatus of the present invention maintains the detection sensitivity as the target gas concentration changes, as it becomes higher.
The device using 100MHz (N = 5) crystal oscillator is 9MHz (N = 1)
It can be seen that the sensitivity is 24 times higher than that using a quartz oscillator.

[0025]

As described above, the apparatus for detecting small-sized gas or airborne particles in the present invention can be used to detect volatile organic substances such as aldehydes such as formaldehyde, toluene, xylene, chlorobenzene and the like. Hazardous substances mainly contained in house building materials such as aromatics, phthalates, adipic esters, etc., termite control agents (synthetic pyrethroids such as chlorpyrifos, phoxime, permethrin, organic phosphorus, and organic chlorines) Compound),
Halogen gas such as chlorine, optically active gas, air pollutant gas such as SOx and NOx, harmful gas (for example, toxic gas such as sarin and ipert), floating particulates during diesel vehicle disposal, floating particulate asbestos generated from dismantling construction sites, and pests Even if the amount of gas components such as pesticides such as pesticides, bactericides, volatile endocrine disrupters (environmental hormones) and dioxins is extremely small, the amount of gas components or the amount of airborne particulates can be detected accurately and easily. It is small and easy to handle and operate.
Even in the environmental monitoring of aircraft, ships, deep sea exploration vessels, spacecraft, outdoors, etc., the measurement and monitoring of volatile components such as harmful gases or airborne particulates can be performed continuously and simply.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a simplified gas or airborne particulate detection device according to the present invention.

FIG. 2 is an explanatory diagram of a conventional gas or airborne particulate detection device.

FIG. 3 shows the detection sensitivity to various gases of the detection device of the present invention using a 9 MHz (N = 1) crystal resonator.

FIG. 4 shows detection sensitivity to various gases of the detection apparatus of the present invention using a 50 MHz (N = 1) crystal resonator.

FIG. 5 shows detection sensitivity to various gases of the detection device of the present invention using a 100 (N = 3) MHz quartz oscillator.

FIG. 6 shows detection sensitivity to various gases of the detection apparatus of the present invention using a 100 (N = 5) MHz quartz oscillator.

FIG. 7 shows the detection sensitivity with respect to the concentration of acetone gas of the detection device of the present invention using a 9 MHz (N = 1) quartz oscillator.

FIG. 8 shows the detection sensitivity with respect to the acetone gas concentration of the detection device of the present invention using a 50 MHz (N = 1) quartz oscillator.

FIG. 9 shows the detection sensitivity with respect to the acetone gas concentration of the detection apparatus of the present invention using a 100 (N = 3) MHz quartz oscillator.

FIG. 10 shows the detection sensitivity with respect to the acetone gas concentration of the detection apparatus of the present invention using a 100 (N = 5) MHz quartz oscillator.

Claims (5)

[Claims] (A) A detection target gas or a gas containing airborne fine particles is brought into contact with a quartz oscillator having a coating film on its surface which has absorptivity to the gas to be detected or airborne fine particles. A means for adsorbing only the target gas or airborne particulates to the quartz oscillator. (B) Oscillating a quartz oscillator that adsorbs the target gas or airborne particulates and measuring the frequency change due to the adsorption of the gas or airborne particulates. And a means for converting and displaying the concentration of the gas or airborne particulates, and oscillating the quartz oscillator adsorbing the gas to be detected or the airborne particulates described in (B) above. The means for measuring and displaying the frequency change includes: (C) means for oscillating a quartz oscillator in which a gas to be detected or airborne fine particles is adsorbed in a housing;
(D) means for measuring a change in the oscillation frequency generated by the oscillation of the quartz oscillator, and (E) means for displaying the change in the frequency, which are integrated and integrated. An airborne particulate detector. 2. The simple small gas or airborne particulate detection device according to claim 1, wherein said device is portable. 3. The simple small gas or airborne particulate detection device according to claim 1, wherein a quartz oscillator having a high fundamental frequency is used. 4. The simple small gas or air according to claim 1, wherein the overtone of the crystal oscillator having a high fundamental frequency according to claim 3 is used for detecting fine particles suspended in the gas or air. Medium suspended particle detector. 5. A simple method for detecting a gas to be detected or airborne particulates using the simple small gas or airborne particulate detection device according to claim 1.