JP2007121064A - Gas sensing element holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sensing element holder excelling in UV resistance and avoiding uneven color fading or uneven color development caused by the residence of air. <P>SOLUTION: The gas sensing element holder 10 comprises a holder body 11, and upper and under structures 12 and 13 mounted on upper and under openings, respectively, in the holder body 11. A gas sensing element 3 for detecting gaseous atmospheric pollutants is housed within the holder body 11 to stick a UV protection film 4 on its peripheral surface. A temperature difference is caused between upper and under parts of the element holder 10. This temperature difference guides specimen air 5 from the under structure 13 into the holder body 11 and exhausts it to the exterior from the upper structure 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is intended to detect environmental concentrations of gaseous air pollutants with high environmental risks, particularly ozone, which constitutes the main component of photochemical oxidants, and nitrogen dioxide generated by combustion of substances at the individual and household level. The present invention relates to a gas detector holder in which a gas detector comprising an ozone detector, a nitrogen dioxide detector and the like can be used outdoors under sunlight irradiation.

  Ultra-compact that can be carried by individuals by using a small porous body such as filter paper or porous glass impregnated with an organic dye that fades selectively by reacting with the gas to be detected (for example, ozone). Small storage type sensors for gas detection have been developed (see, for example, Patent Documents 1 to 5).

  In addition, by using a small porous body such as porous glass impregnated with an organic dye that selectively reacts with the gas to be detected (for example, nitrogen dioxide) to develop a color, the gas detector is super A small storage type sensor for gas detection has been developed (see, for example, Patent Documents 6 and 7).

  Among these accumulation-type sensors used for gas concentration measurement, the sheet-shaped gas detector mainly detects the amount of personal exposure to gas for one day, and is a special work that uses ozone gas for ozone sterilization. Assume an exposure assessment for workers. This sheet-like gas detector is designed to fade at an accumulated concentration amount (concentration standard × time) determined by the labor standard with an average working time of 8 hours.

  However, the risk of exposure to gaseous air pollutants (ozone) is considered to be more significant in outdoor environments with strong sunlight than in indoor environments, and ultraviolet rays (hereinafter abbreviated as UV) of gas (ozone) detectors. ) Was strongly demanded for outdoor use under sunlight irradiation.

  Organic dyes that fade (or develop color) by selective reaction with the gas to be measured (ozone or nitrogen dioxide) exhibit a fading (or color development) reaction against ultraviolet rays contained in sunlight, so they are impregnated with reagents. If the filter paper or porous glass itself is taken out outdoors under sunlight, the change in absorbance caused by exposure to the gas to be measured (ozone or nitrogen dioxide) (decrease in absorbance at a specific wavelength may be discolored or Only an increase in absorbance appeared as color development) could not be detected.

  Therefore, the present inventors devised a UV-resistant gas detector batch 1 as shown in FIGS. 14 (a) and 14 (b). This gas detector batch 1 is obtained by attaching a sheet-like gas detector 3 on a mount 2 and covering the gas detector 3 with a UV cut film 4 having a function of cutting UV components. In this gas detector batch 1, an interval d of 1 to 5 mm is set between the gas detector 3 and the UV cut film 4 in order to enable contact between the gas detector 3 and the sample air 5. . In addition, what is shown by the code | symbol 6 is the color chart which displayed the precautions on use while converting and instruct | indicating the density | concentration of the detected gas visually by the color condition of fading (or coloring).

  Here, in the gas detector batch 1 shown in FIG. 14, the sample air 5 to be detected is provided between the two opposing sides of the UV cut film 4 covering the upper surface of the gas detector 3 and the mount 2. The gas detector 3 should have been introduced through the opening 7 and reacted selectively with the organic dye in the gas detector 3 to cause the gas detector 3 to fade (or develop color).

  However, according to the experimental result, as shown by the broken line in FIG. 14B, the fading (or color development) due to the gas (ozone or nitrogen dioxide) in the vicinity of the side edge near the opening 7 of the gas detector 3 and in the center. ) 8 became non-uniform, and it was found that invariant portions 9 that did not fade or develop color were left at both ends in the center in the width direction.

  This is probably because a boundary layer region is formed on the surface of the gas detector 3 due to the viscosity of the air 5, and the sample air 5 is hardly replaced in the central portion of the UV cut film 4.

  On the other hand, in the vicinity of the opening 7, the boundary layer is extremely thin and the sample air 5 reaches the surface of the gas detector 3, so that the gas molecules to be detected from the direction perpendicular to the surface of the gas detector 3 are detected. This is considered to be due to the fact that the color was sufficiently supplied and a fading (or coloring) reaction occurred.

JP 2004-144729 A Japanese Patent Application No. 2004-234430 Japanese Patent Application No. 2004-320387 Japanese Patent Application No. 2005-017977 Japanese Patent Application No. 2005-074635 JP 09-274032 A Japanese Patent Laid-Open No. 2000-081426

  The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to provide an organic dye that fades (or develops color) by UV with a porous glass or a porous material containing cellulose such as filter paper. A gas detector utilizing the above principle of detecting a target gas to be measured (ozone or nitrogen dioxide) by impregnating it into the body, even when the sunlight containing the UV component is strong outdoors, and the interference effect by UV The effect of hindering the selective reaction with the gas to be measured, which is assumed in the absence of UV, is eliminated, and uneven fading or uneven coloring due to stagnation of air can be avoided. An object of the present invention is to provide a gas detector holder.

  In order to achieve the above object, a first invention is a holder mainly used in an outdoor environment under sunlight irradiation, and adsorbs gaseous air pollutants on the surface thereof to selectively react. A gas detector holder that is made of a porous material impregnated with organic dyes that develop or fade in color and incorporates a gas detector that detects air pollutants. The upper and lower parts open and are transparent to visible light. A holder body formed in a cylindrical body, a UV cut film provided on a peripheral surface of the holder body to protect the gas detector from ultraviolet rays, and an air in the holder body provided in an upper opening of the holder body And a lower structure that is provided at a lower opening of the holder body and guides outside air into the holder body.

  According to a second aspect of the present invention, the upper structure has a funnel-shaped opening that extends upward.

  In a third aspect of the present invention, a heat dissipation fin is provided in the opening of the upper structure.

  In a fourth aspect of the present invention, a cooling liquid tank is provided in the upper structure.

  According to a fifth aspect of the present invention, a cooling body that uses heat absorption associated with a phase change of a substance is provided in the upper structure.

  In a sixth aspect of the invention, the lower structure is formed in a shape that expands downward.

  In a seventh invention, the lower structure is made of a transparent material, and at least the lower end side is colored black.

  According to an eighth aspect of the present invention, a heating element using oxidation heat of a substance is provided in the lower structure.

  In a ninth aspect of the invention, the holder body is composed of a double pipe composed of an inner pipe and an outer pipe, a gas detector is provided on either the outer surface of the inner pipe or the inner face of the outer pipe, and the inner pipe and the outer pipe. An annular gap formed between the two is used as an air flow path.

In the first invention, the gas detector is covered and protected from UV by the UV cut film. Therefore, even in an outdoor environment where sunlight is directly irradiated, an error factor of the gas detection concentration value caused by the dye fading effect due to UV irradiation, which is a concentration error factor of greatest concern, can be removed.
When sample air enters the lower structure, it passes through the holder body by convection and is discharged from the upper structure to the outside. Can do.

  In the second invention, since the upper structure is provided with a funnel-shaped opening extending upward, the sample air in the holder is discharged to the outside satisfactorily.

  In the third aspect of the invention, heat is dissipated by the radiating fins provided in the opening of the upper structure, so that the temperature of the upper structure can be kept lower than that of the lower structure. For this reason, an updraft can be generated in the holder body, and the ventilation characteristics of the sample air (flow of sample air from the bottom to the top inside the holder) can be enhanced. As long as the temperature difference is maintained, sample air is always supplied to the surface of the gas detector by the ascending air current, so that uneven color fading or uneven color due to stagnation of air in the gas detector is avoided.

  In the fourth invention, since the cooling tank is provided in the upper structure, the temperature difference between the upper structure and the lower structure can be maintained for a long time, and an ascending air current is generated in the holder body. be able to. Therefore, the ventilation characteristic of the sample air can be improved, and no discoloration unevenness or color unevenness due to the retention of air in the gas detector is prevented.

  In the fifth invention, since the cooling body is provided in the upper structure, the temperature difference between the upper structure and the lower structure can be maintained for a long time, and an upward air flow is generated in the holder body. Can be made. Therefore, the ventilation characteristic of the sample air can be improved, and no discoloration unevenness or color unevenness due to the retention of air in the gas detector is prevented.

  In the sixth aspect of the invention, since the lower structure is formed in a shape that expands downward, the surface area is large and a large amount of sunlight heat is received, so that the ventilation characteristics of the sample air can be improved. Therefore, there is no occurrence of uneven fading or uneven coloring due to the retention of air in the gas detector.

  In the seventh invention, since the lower structure is colored black, while the black portion is irradiated with sunlight, the sunlight is absorbed and becomes a high temperature state, and the surrounding air is heated. For this reason, the heated air expands and causes thermal convection to form an ascending current, passes through the holder body, and is discharged from the upper structure to the outside, thereby improving the ventilation characteristics of the sample air. Therefore, there is no occurrence of uneven fading or uneven coloring due to the retention of air in the gas detector.

  In the eighth invention, since the heating element using the oxidation heat of the material provided in the lower structure is provided, the temperature difference between the upper structure and the lower structure can be maintained for a long time. . Therefore, an updraft can be generated in the holder body, and the ventilation characteristics of the sample air can be enhanced.

  In the ninth invention, since the holder body has a double tube structure and the flow path of the sample air is between the inner tube and the outer tube, the cross-sectional area of the passage is reduced and the flow rate of the rising air flow is increased. And the ventilation characteristics of the sample air can be enhanced.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is an external perspective view of a gas detector holder showing a first embodiment of the present invention, FIG. 2 is a sectional view of the holder, and FIG. 3 is a perspective view of a holder body from which an upper structure and a lower structure are removed. FIG. The same components as those described in the prior art are denoted by the same reference numerals. In these drawings, a gas detector holder generally indicated by reference numeral 10 includes a holder main body 11 containing a sheet-like gas detector 3 for detecting gaseous atmospheric pollutants (for example, ozone or nitrogen dioxide), and the holder. The upper structure 12 is formed of a hollow body provided in the upper opening 14 a of the main body 11, and the lower structure 13 is also formed of a hollow body provided in the lower opening 14 b of the holder main body 11. The upper structure 12 and the lower structure 13 are detachably attached to the holder main body 11, respectively, so that the gas detector 3 can be easily attached and removed.

  The holder body 11 is formed in a cylindrical shape whose both ends are opened by plastic or glass transparent to visible light, and a sheet for detecting gaseous air pollutants (for example, ozone or nitrogen dioxide) inside. A gas detector 3 is stored. A UV cut film 4 and a color chart 6 for protecting the gas detector 3 from UV are attached to the outer peripheral surface thereof.

  As a method for storing the gas detector 3 in the holder main body 11, when the gas detector 3 is a sheet such as paper, it is elastically deformed into a cylindrical shape as shown in FIG. It is stored in close contact with the inner peripheral surface of the holder body 11 by elasticity. On the other hand, when the gas detector 3 uses porous glass as a base material, both side edges of the gas detector 3 are formed in two grooves 15 formed in the axial direction on the inner peripheral surface of the holder body 11 as shown in FIG. It is stored by inserting the part.

  Thus, if the gas detector 3 is housed in the holder main body 11 and protected from UV by the UV cut film 4, the UV contained in the sunlight directly reaches the organic dye of the gas detector 3 and the gas to be detected. Can be prevented from interfering with selective chemical reactions.

  When the gas detector 3 is accommodated in the holder main body 11 covered with the UV cut film 4, it is essential to improve the ventilation characteristics of the sample air 5 in the holder main body 11 and prevent the retention.

  Therefore, in the present invention, as described above, the upper structure 12 and the lower structure 13 are attached to the upper opening 14a and the lower opening 14b of the holder main body 11, and the sample air 5 moves down the holder 10 by these structures. It flows from the top to the top.

  The upper structure 12 is integrally formed of plastic, metal or the like, and has a cylindrical cap portion 12A having a female screw 16 formed on the inner surface and opened downward, and an upper center of the cap portion 12A. The cap portion is formed by a funnel-shaped opening 12B that is integrally projected so as to increase in diameter toward the outside, and the female screw 16 is screwed to a male screw 17 formed on the outer peripheral surface of the upper end side of the holder body 11. 12 </ b> A is attached to the upper opening 14 a of the holder body 11. Further, a pair of hooks 18 are integrally projected on the outer peripheral surface of the cap portion 12A, and a string for suspending the gas detection body holder 10 is inserted into these hooks 18. . The opening 12B is open at both upper and lower ends and communicates with the inside of the cap 12A.

  The lower structure 13 is formed in a frustoconical shape (skirt shape) whose both ends are opened and spread downward by a plastic transparent to visible light, preferably a conductive plastic. The surface is colored black. In addition, 20 is a black colored part and 21 is a non-colored part (transparent part). The lower structure 13 is attached to the lower opening 14 b of the holder body 11 via a connection ring 22. The connection ring 22 is made of a material having low heat conductivity, preferably a heat insulating material, so that the high surface temperature of the heated lower structure 13 is not transmitted to the holder body 11 by heat conduction. Further, on the upper and lower ends of the outer peripheral surface of the connection ring 22 are formed male screws 25 and 26 into which the female screw 23 of the holder body 11 and the female screw 24 of the lower structure 13 are screwed.

  Regarding the lower structure 13, as long as the solar heat absorption continues in the colored portion 20, the temperature is kept higher than that of the non-colored portion 21.

  If the black colored portion 20 is provided on the inner peripheral surface on the lower end side of the lower structure 13, the colored portion 20 absorbs solar heat while being irradiated with direct sunlight, so the temperature of the lower structure 13 is not colored. The sample air 5 at the bottom of the holder is heated in comparison with the part 21. For this reason, the heated sample air 5 is thermally expanded and becomes an ascending airflow due to buoyancy and ascends in the lower structure 13, the holder main body 11 and the upper structure 12, and passes outside from the upper opening of the upper structure 12 Discharged. The range where the colored portion 20 is formed is about 2/3 of the lower side of the lower structure 13.

For air, kinematic viscosity coefficient ν = 1.501 × 10 ⁻⁵ (m ² s ⁻¹ ) (20 ° C.), temperature conductivity K = 0.216 × 10 ⁻⁴ (m ² s ⁻¹ ), Since the volume expansion coefficient α = 3.41 × 10 ⁻³ (° C. ⁻¹ ), assuming that the height of the holder body 11 is d = 5 cm, the friction between the tube wall and the air is the critical Rayleigh number. Even if the value 1708 in a certain case is taken, the temperature difference for causing thermal convection is about ΔT = 0.1 ° C. That is, the following formula (1)

The required temperature difference is at most 0.1 ° C.

  Thermal convection occurs when the lower structure 13 is irradiated with sunlight and the temperature of the lower structure 13 is higher than the upper structure 12 by the temperature equal to or higher than the critical temperature indicated by the above formula (1). The sample air 5 heated in the peripheral part of the end-expanded lower structure 13 is collected by being raised in the lower structure 13 by this thermal convection and introduced into the cylindrical holder body 11. Since the gas detector 3 is accommodated in the holder main body 11 in parallel with the axis of the holder main body 11, the sample air 5 flows so as to surround the gas detector 3, and around the gas detector 3. Ventilate the air.

Here, the surface temperature when the black colored portion 20 of the lower structure 13 is irradiated with sunlight will be considered.
The value of the radiant intensity per unit area / unit time (solar constant S) incident on the surface perpendicular to the sun rays at the outer edge of the Earth atmosphere layer is about 1.37 (kW / m ² ). Of this, about 30% is lost due to reflection by clouds and the like, and about 20% is absorbed by the ozone layer and water vapor in the atmosphere, but the remaining 50% reaches the ground surface. Therefore, the solar radiation intensity received by a surface perpendicular to sunlight on the ground surface is estimated to be about 664 W / m ² .

A plate installed in an outside air temperature of 25 ° C and receiving the surface solar radiation intensity (S ₀ =) 664 (W / m ² ) as radiation energy from the sun (for simplicity, placed perpendicular to the sunlight )), In the initial state in which heat transfer due to convection does not occur, the net energy absorbed from the sun is balanced by the radiant heat exchange with long wavelengths with the surroundings. Assuming that the rate is α (see Table 1) and the Stefan-Boltmann coefficient is σ (= 5.67 × 10 ⁻⁸ (W / m ² · K ⁴ )), the following equation is established.

When the surface of the black portion 20 of the lower structure 13 is calculated using α _sun = 0.96 and α _{25 ° C.} = 0.95 from Table 1, T = 374.8 (K) = 102 (° C.).

Of course, since the black colored portion 20 is not always perpendicular to sunlight, the surface temperature of 102 ° C. may be considered as the maximum value. For reference, assuming white color, α _sun = 0.12 and α _{25 ° C.} = 0.9 from Table 1, T _white
= 311K = 38.7 ° C. As predicted, it can be confirmed that the white surface is cooler than the black surface for sunlight.

  In the case of the present embodiment, the lower end portion 20 of the lower structure 13 is colored black, and the upper portion 21 (including the holder main body 11) is transparent. Therefore, the black colored portion 20 is not colored. There is no difference that the temperature becomes higher than that of the portion 21. And if the temperature difference is 0.1 degreeC or more, a thermal convection will occur.

  Next, how much the temperature of the black colored portion 20 changes due to the generated natural convection will be considered. Convective heat transfer is given by the following equation (3) according to Newton's law of cooling.

Here, the heat transfer rate q (W) by convection is proportional to the overall temperature difference between the surface temperature (T _surface ) and the fluid temperature (T _∞ ) and the heat transfer area A, and the proportional coefficient h (W / m ² ) is the heat transfer coefficient by convection in the vertical direction.

  Therefore, the energy balance equation when there is thermal convection is the following equation (4).

Convection air temperature (T _∞), rather than the outside air temperature 25 ° C., although higher temperatures than 0.1 ° C. by the formula (1), the here approximated as substantially equal, determining the surface temperature (T _surface) The unknown in equation (4) is the heat transfer coefficient h due to convection in the vertical direction.

In order to simplify the problem, a black colored vertically installed plate receiving surface solar radiation intensity (S _o =) 664 W / m ² is insulated on the back side, under air at an ambient temperature of 25 ° C. The surface temperature (T _surface ) when heat is radiated by free convection is obtained.

The heat transfer from the plate is assumed to be an isothermal flow rate. Further, since the surface temperature to be obtained (T _surface ) is not known, the film temperature (T _f ) and the physical properties of air are appropriately assumed. Since the thermal conductivity in the vertical direction of natural convection is approximately h _o = 10 (W / m ² · ° C.), approximately the difference ΔT (= T _surface− T _∞ ) between the surface temperature and the fluid temperature. As an approximate value, ΔT = S _o · α _sun / h _o = 664 · 0.96 / 10 = 64 ° C. is obtained. The film temperature at this time is T _f = 64/2 + 25 = 57 ° C. The physical properties of air at 57 ° C. are as follows: kinematic viscosity ν = 18.73 × 10 ⁻⁶ (m ² / s), volume expansion coefficient β = 1 / T _f = 3.03 × 10 ⁻³ ° C., thermal conductivity Using κ = 0.02851 (W / m · ° C.), Prandtl number Pr = 0.701, the characteristic length of the system is x = 5 × 10 ⁻² (m), Nu is the Nusselt number, and the modified Grashof number When Gr ^* is obtained, the following equation (5) is obtained.

  It can be seen that the flow in this range is laminar. Accordingly, in the laminar flow region, the local heat transfer coefficient is expressed by the following equation (6).

  Then, the following equation (7) is obtained by solving the equation (6) in reverse.

Since the value of this local heat transfer coefficient (hx) is larger than the approximate value h _o (= 10 (W / m ² · ° C.) used to estimate T _f , if ΔT is recalculated, ΔT = S _o · α _sun / h _x = 664 · 096 / 12.5 = 51.0 ° C. Thus, the corrected film temperature is T _f = 51/2 + 25 = 50.5≈51 ° C. 51 The physical property values of air at ° C are kinematic viscosity ν = 18.12 × 10 ⁻⁶ (m ² / s), volume expansion coefficient β = 1 / T _f = 3.08 × 10 ⁻³ (° C. ⁻¹ ), Using thermal conductivity κ = 0.02806 (W / m · ° C) and Prandtl number Pr = 0.703, the corrected Grashof number is Gr _x ^* = 1.31 x 10 ⁷ , so the local heat transfer coefficient is in _{h x = 12.519 (W / m} 2 · ℃), is substantially converged to the value previously obtained. accuracy does not improve even if the more repetitive calculations. Thus, the new Temperature difference using the convergence value have is a △ T (= T _{surface -T ∞) = S o · α} sun / h x = 664 · 0.96 / 12.5 = 51.0 ℃.

Therefore, even when there is vertical convection, the average surface temperature of the black colored portion 20 is T _surface = 51 + 25 = 76 ° C. Of course, since the black colored portion 20 is not always positioned perpendicular to the sunlight, the surface temperature of 76 ° C. may be considered as the maximum value when there is thermal convection.

  In any case, it has been revealed that the surface temperature of the colored portion 20 caused by the surface solar radiation intensity can be higher than the critical temperature given by the equation (1).

  Thus, in the first embodiment of the present invention, the retention of the sample air 5 that occurs when the upper portion of the gas detector 3 shown in FIG. 14 is covered with the UV cut film 4 is caused by thermal convection. Since this is avoided, the discoloration unevenness (or uneven coloration) 8 (see FIG. 14B) of the gas detector 3 due to the retention of the sample air 5 can be eliminated. Needless to say, since the UV cut film 4 is provided, UV in sunlight does not reach the gas detector 3 directly.

  In the first embodiment described above, the holder main body 11 has been described assuming a cylindrical shape that can be easily processed, but is not limited to this. For example, like the gas detector holder 30 in the second embodiment shown in FIG. 4, the holder main body 31 may be an n-shaped cylindrical body with n being an integer of 3 or more, and more Needless to say, a cylindrical body having an arbitrary cross-sectional shape other than a square shape, for example, a cylindrical body having an elliptical cross-sectional shape perpendicular to the center line may be used. FIG. 4 shows an example in which the holder body 31 is formed in a square tube shape with n = 4. For this reason, the cylindrical portion 32A of the upper structure 32 is formed in a rectangular tube shape, the opening 32B is formed in a reverse truncated pyramid shape (reverse trapezoid), and the lower structure 33 is expanded downward. It has a truncated pyramid shape (trapezoid). And the upper structure 32 and the lower structure 33 are attached to the holder main body 11 by fitting and bonding. Other structures are the same as those in the first embodiment.

  In the case of the gas detector holder 10 in the first embodiment, the heat absorbed in the lower part due to thermal convection moves upward inside the holder body 11 as the heated sample air 5 rises.

  As a result of the warm air reaching the upper part of the holder body 11 heating the upper part of the holder body 11, the temperature difference between the upper part and the lower part of the holder 10 formed at the beginning when irradiated with sunlight gradually decreases. Eventually, the updraft due to thermal convection disappears when the temperature difference between the upper part and the lower part disappears.

  In order for this updraft to continue, it is necessary to maintain a temperature difference between the upper part and the lower part of the holder 10.

  As measures for maintaining the temperature difference and preventing the ascending airflow from being lost as a result, for example, (1) Increasing the heat capacity of the upper part of the holder to prevent the temperature from being raised by some heating, (2) Holder It is preferable to take measures such as improving the heat dissipation characteristics of the upper portion so that the temperature does not rise due to heat dissipation even when heated.

  Therefore, in the gas detector holder 40 shown in FIGS. 5 and 6 as the third embodiment, the upper structure 42 is provided with the cap part 42A and the inverted truncated conical opening part 42B whose diameter is increased upward. A plurality of radiating fins 45 are integrally projected on the outer peripheral surface of the opening 42 at equal intervals in the circumferential direction. The holder main body 11 and the lower structure 13 are exactly the same as those in the first embodiment.

  In consideration of the design of the holder 40, the upper structure 42 may be integrally cast and plated with a metal such as iron. The reason for plating is to prevent sunlight from being reflected by the surface under sunlight irradiation and the temperature of the upper structure 42 due to absorption of radiant heat from rising.

  Further, as a fourth embodiment, in the gas detector holder 50 shown in FIGS. 7 and 8, the coolant 55 is injected into the cap portion 52A attached to the upper opening of the holder body 11 of the upper structure 52. In the center of the tank 52A, an inverted frusto-conical opening 52B that is expanded upward and communicates with the inside of the holder body 11 is integrally provided. An inlet 56 for injecting the coolant 55 is provided on the peripheral surface of the coolant tank 52 </ b> A, and the inlet 56 is closed by a plug 57. Other structures are the same as those in the first embodiment.

  As described above, also in the third and fourth embodiments, the sample air 5 warmed by the lower structure 13 that is continuously heated by the sunlight irradiation rises by the heat convection, and the holder body 11 and the upper structure 42 or The air is exhausted to the outside through the opening 42B or 52B through 52. That is, an ascending airflow is always generated inside the holder main body 11 due to the air heated in the lower part, and the holder main body is ventilated, so that it does not stay.

9 and 10 are an external perspective view and a sectional view of a gas detector holder showing a fifth embodiment of the present invention.
In the gas detector holder 60 in this embodiment, in order to more positively maintain the temperature difference between the upper part and the lower part of the holder, the cooling body 61 is provided on the outer periphery of the funnel-shaped opening 12B provided in the upper structure 12. The heating element 62 is provided on the outer periphery of the lower structure 13. Other structures are the same as those of the first embodiment.

  As the cooling body 61, a cooling body using endotherm accompanying a phase change of a substance (for example, “Cold Pita” and “Hot Sama Sheet” are both trade names) is used. Such a cooling body 61 exhibits a cooling effect by depriving heat of vaporization when the moisture of the gel composed of a highly hydrous polymer base or a water-soluble polymer base evaporates.

  As the heating element 62, a heating element using the oxidation heat of the substance (for example, “Hocalon” using the oxidation heat of iron powder, a trade name) is used. In this case, the lower structure 13 is made of a metal material in order to improve heat conduction.

  11 is an external perspective view of a gas detector holder showing a sixth embodiment of the present invention, FIG. 12A is a sectional view of the holder, FIG. 11B is a perspective view of an upper presser fin, and FIG. Is a perspective view of the lower presser fin, and FIG. 13 is a configuration diagram of the inner tube structure. In these drawings, in the gas detector holder 70 in this embodiment, the holder main body 71 is constituted by a double tube comprising an outer tube 72 and an inner tube (also referred to as an inner tube structure) 73.

  The outer tube 72 has the same structure as that of the holder main body 11 shown in FIGS. 1 to 3, and the upper structure 12 shown in FIG. 1 is attached to the upper end opening thereof. The upper structure 42 with the heat dissipation fins shown, the upper structure 52 with the coolant tank 52A shown in FIG. 7, or the upper structure 12 with the cooling body 61 shown in FIG. 9 may be used.

  In any case, with respect to the structure of the inner tube 73 having a double-pipe structure, as shown in FIG. 13, a hollow inner tube body 73A composed of a heat insulating member and an upper side of the inner tube body 73A are provided. The inner tube upper structure 73B having a conical head portion and the inner tube lower structure 73C formed in a reverse truncated cone shape provided at the lower portion of the inner tube body 73A are formed in a substantially spindle shape. ing.

  The inner pipe upper structure 73B is made of a metal material, and is filled with a cooling body 61 that uses heat absorption associated with the phase change of the substance, and the conical head has a plurality of parts to dissipate vaporized gas. A small hole 74 is formed.

  On the other hand, the inner pipe lower structure 73C is also made of a metal material, but the inside is filled with a heating element 62 using the oxidation heat of the substance. A plurality of small holes 75 are formed in the bottom surface of the inner pipe lower structure 73C to suck in oxygen.

  In such a spindle-shaped inner tube structure 73, the inner tube main body 73A and the inner tube upper structure 73B are inserted into the outer tube 72, and the inner tube lower structure 73C is inserted into the lower structure 13. 12 (b) and 12 (c), the upper holding fin 77 and the lower holding fin 78 hold it.

  When the inner tube structure 73 is held in the outer tube 72 via the fins 77 and 78 in this way, an annular gap 80 is formed between the inner tube main body 73A, the inner tube upper structure 73B, and the outer tube 72. Therefore, the gap 80 is used as a flow path for the sample air 5.

  As described above, in the present embodiment, the inner pipe structure 73 includes the cooling body 61 and the heating element 62 in the upper and lower portions, respectively, so that the sample air 5 in contact with the inner pipe lower structure 73C is warmed. As a result, an ascending air current is formed, collected by the lower structure 13 of the outer tube 72, and guided to an annular flow passage 80 formed between the outer tube 72 and the inner tube structure 73. The gas detector 3 attached to either the inner surface of the outer tube 72 or the outer surface of the inner tube 73 selectively fades (or develops color) by selectively reacting with the gas to be detected in the introduced sample air 5. .

  The sample air 5 that has risen through the flow passage 80 between the inner tube structure 73 and the outer tube 72 warms the upper structure 12 of the outer tube 72, but in the upper structure 73 B for the inner tube of the inner tube structure 73. The temperature difference between the upper structure value A12 and the lower structure 13 of the gas detector holder 70 can be maintained for a long time by the filled cooling body 61, and an upward air flow is continuously generated in the holder main body 71. be able to. Therefore, the ventilation characteristic of the use air 5 can be improved, and the color fading unevenness and the color unevenness due to the retention of the air in the gas detector 3 do not occur.

  As described above, in the present invention, the gas detector 3 is protected from the UV by the UV cut film 4, so that UV, which is a concentration error factor which is most feared in use in an outdoor environment where sunlight is directly irradiated, is used. It is possible to remove an error factor of the gas detection density value caused by the fading (or color development) effect of the pigment in the gas detector 3 by irradiation, and the detection accuracy can be improved.

  In the present invention, the lower part of the holder is configured to have a higher temperature than the upper part, and the sample air 5 is heated by utilizing this temperature difference, so that the temperature difference is generated. As long as is maintained, the sample air required by the gas detector 3 can be sufficiently ventilated by this updraft. Thereby, since the sample air is always supplied to the surface of the gas detector 3, it is possible to prevent the occurrence of uneven fading and uneven coloring due to the retention of air.

  As described above, gas detection by a colorimetric reaction type gas detector composed of a porous body impregnated with an organic dye can be performed without being interfered by UV, even outdoors where UV or other intense irradiation occurs. This is possible without causing sample air retention due to the covering of the cut film 4.

It is an external appearance perspective view of the gas detection body holder provided with the ultraviolet-ray resistance which shows the 1st Embodiment of this invention. It is sectional drawing of the holder. It is a perspective view of a holder main body. It is a perspective view of the gas detection body holder which shows the 2nd Embodiment of this invention. It is a perspective view of the gas detection body holder which shows the 3rd Embodiment of this invention. It is sectional drawing of the holder. It is a perspective view of the gas detection body holder which shows the 4th Embodiment of this invention. It is sectional drawing of the holder. It is a perspective view of the gas detection body holder which shows the 5th Embodiment of this invention. It is sectional drawing of the holder. It is an external appearance perspective view of the gas detection body holder which shows the 6th Embodiment of this invention. (A) is sectional drawing of the holder, (b) is a perspective view of the upper presser fin, (c) is a perspective view of the lower presser fin. It is a block diagram of an inner pipe structure. (A) is a perspective view which shows the prior art example of a gas detection body batch, (b) is a top view of the same gas detection body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Gas detection body, 4 ... UV cut film, 10 ... Gas detection body holder, 11 ... Holder main body, 12 ... Upper structure, 12B ... Funnel-shaped opening, 13 ... Lower structure, 20 ... Colored part, 42 DESCRIPTION OF SYMBOLS ... Upper structure, 45 ... Thermal radiation fin, 52 ... Upper structure, 52A ... Coolant tank, 61 ... Cooling body, 62 ... Heat generating body, 72 ... Outer pipe, 73 ... Inner pipe.

Claims (9)

This holder is mainly used in outdoor environments under sunlight, and is impregnated with organic dyes that develop or fade by adsorbing gaseous air pollutants on the surface and reacting selectively. In the gas detector holder that is made of a porous body and incorporates a gas detector that detects the air pollutant,
A holder main body formed in a cylindrical body that is open at the top and bottom and transparent to visible light; a UV cut film that is provided on the peripheral surface of the holder main body to protect the gas detector from ultraviolet rays; and An upper structure provided in the upper opening for discharging the air in the holder body to the outside, and a lower structure provided in the lower opening in the holder body for guiding the outside air into the holder body. Characteristic gas detector holder. The gas detector holder according to claim 1,
The gas detector holder, wherein the upper structure has a funnel-shaped opening extending upward. In the gas detector holder according to claim 2,
A gas detector holder characterized in that a heat dissipating fin is provided in an opening of the upper structure. In the gas detector holder according to any one of claims 1 to 3,
A gas detector holder, wherein a coolant tank is provided in the upper structure. In the gas detector holder according to any one of claims 1 to 3,
A gas detector holder, wherein the upper structure is provided with a cooling body utilizing endotherm accompanying a phase change of a substance. The gas detector holder according to claim 1,
The gas detector holder, wherein the lower structure is formed in a shape that expands downward. The gas detector holder according to claim 1 or 6,
The gas detector holder, wherein the lower structure is made of a transparent material, and at least the lower end is colored black. In the gas detector holder according to any one of claims 1, 6, and 7,
A gas detector holder characterized in that a heating element using oxidation heat of a substance is provided in the lower structure. In the gas detector holder according to any one of claims 1 to 8,
The holder body is composed of a double pipe composed of an inner pipe and an outer pipe, a gas detector is provided on either the outer surface of the inner pipe or the inner surface of the outer pipe, and is formed between the inner pipe and the outer pipe. A gas detector holder, wherein the annular gap is used as an air flow passage.

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