JP5334272B2 - Gas quantification generator for volatile organic compounds - Google Patents

Description

  The present invention relates to a heating apparatus for generating gas from volatile organic compounds (VOC) and an apparatus for quantitatively generating VOC gas without a power source such as a pump. More specifically, the present invention relates to an apparatus for quantitatively generating VOC gas by molecularly diffusing VOC contained in a container through a specific filter.

A representative example of a device that generates VOC gas quantitatively includes a device that includes an impinger, an air pump, a silica gel tube, and a flow meter (see Non-Patent Document 1). In such an apparatus, a VOC solution is injected into an impinger and air is allowed to flow over the liquid surface to diffuse VOC gas to the outside. However, such a device requires (1) a power source such as an air pump to generate gas from the VOC, (2) the piping is long and easy to condense , (3) the concentration of the generated gas varies. Improvement is desired in that it is easy and (4) it is difficult to control the generated gas to a low concentration.

  Another example of a device that quantitatively generates VOC gas is a device that generates gas without a power source by introducing VOC into a permeation tube or a diffusion tube and allowing VOC to molecularly diffuse (non-patent document). Reference 2). As a specific example of a device using a permeation tube, by enclosing VOC (liquefied gas) in a fluororesin tube and holding the tube at a constant temperature so that a certain amount of liquefied gas permeates and diffuses through the tube wall, An apparatus that continuously generates a small amount of standard gas can be used. However, since such a permeation tube constitutes a large part of the apparatus, (1) the amount of generated gas is excessive, and in order to generate a constant concentration of gas, dilution of air, nitrogen, etc. Improvement is desired in that it is necessary to supply gas quantitatively, (2) the tube is easily contaminated during measurement, and measurement errors are likely to occur. On the other hand, as a specific example of an apparatus using a diffusion tube, there is an apparatus in which a cylindrical diffusion tower is provided in the upper part of a glass liquid storage container, and VOC introduced into the container is evaporated and diffused from the upper part of the diffusion tower. However, such an apparatus is desired to be improved in that the upper part of the diffusion tower is open, so that it is easily affected by the external environment such as wind, and the amount of generated gas is likely to vary.

  Yet another example of a device that quantitatively generates VOC gas is a device having a structure in which a VOC containing container such as a screw tube is covered with a silicone film and sealed with a perforated cap (Non-Patent Document). 3). However, in such a device, (1) VOC liquid or gas is likely to leak from the gap of the cap due to poor sealing performance of the container, and the generation rate is likely to vary. (2) The amount of permeation increases in the silicone membrane. The amount of gas generated is likely to increase. (3) Because the solid difference between the screw tube and the silicone membrane is large, the performance between the generators tends to vary. (4) The silicone membrane is formed by VOC during transportation of the device. Improvements are desired in that they are easily wetted, and when the silicone film gets wet, the gas generation rate tends to vary. Regarding (4), in order to prevent wetting of the diffusion filter during transportation, VOC may be introduced into the screw pipe at the installation location, but there is a possibility that VOC may be scattered at the installation location. Further improvement is desired in that the operator touches the VOC and an error occurs during measurement.

“Environmental Chemistry” Vol. 12, P847-854 (2002) Gastech website, “Calibration gas generator” (searched on November 2005), Internet <URL: http: // www. gastec. co. jp / fp top Japan. htm> 2002 Health and Welfare Research Grants, Summary Report H13-Life-017

As described above, there have been several reports on devices that quantitatively generate VOC gas, but the current situation is that further improvements are desired for all of them. Therefore, the present invention can quantitatively generate a small amount of VOC gas, and can easily prevent leakage of VOC during transportation and wetting of the diffusion filter due to VOC , and further measurement. It is an object of the present invention to provide a simple and high-performance VOC gas quantitative generation device that is easy to install at a place.

  The inventors of the present invention have intensively studied a device that quantitatively generates VOC gas by molecular diffusion, and accurately diffuses a small amount of VOC gas by molecularly diffusing VOC contained in a container through a specific diffusion filter. The inventors have found that it is possible to control, and have completed the present invention. That is, the present invention relates to the following.

  A first aspect of a volatile organic compound gas quantitative generation apparatus according to the present invention is a container that contains a volatile organic compound, and covers the opening of the container and generates a gas generated from the volatile organic compound in the container. A sintered filter obtained by sintering the polymer particles, the cap having a diffusion port for diffusing outside, and a diffusion filter for covering the diffusion port of the cap and controlling the diffusion of the gas It is characterized by being. Here, the pore diameter of the sintered filter is preferably in the range of 5 to 300 μm.

A second aspect of the volatile organic compound gas quantitative generation device according to the present invention includes a first container that contains a volatile organic compound, a cap that covers the opening of the first container, and a through hole that penetrates the cap. An induction tube for guiding the gas generated from the volatile organic compound to the outside of the first container; and a diffusion tower having a diffusion filter for controlling diffusion of the gas induced by the induction tube, The diffusion filter is a sintered filter obtained by sintering polymer particles. Here, the pore diameter of the sintered filter is preferably in the range of 5 to 300 μm.
Moreover, in the gas fixed-quantity generator according to the present invention, the gas quantitative generator further includes a second container that accommodates the entire first container, and the guide tube passes through a second cap that covers the opening of the second container. Preferably, the gas is guided to the outside of the second container. The gas diffusion rate is preferably 0.01 to 0.50 mg / hour at 20 ° C.

  The gas fixed-quantity generation device according to the present invention is extremely simple as compared with a device having a drive unit such as a pump, can be easily installed at a measurement place, and can accurately control a minute amount of VOC gas diffusion. Is possible. Furthermore, according to the VOC gas quantitative generator according to the present invention, it is possible to reliably prevent problems such as leakage of VOC during transportation of the device and wetting of the diffusion filter due to VOC.

It is a perspective view which illustrates the structure of the VOC gas fixed quantity generator by this invention. It is a perspective view which illustrates another structure of the VOC gas fixed quantity generator by this invention. It is a perspective view which illustrates another structure of the VOC gas fixed quantity generator by this invention.

Hereinafter, the gas fixed quantity generator according to the present invention will be described in detail with reference to the drawings. However, the gas fixed-quantity generation device shown in the figure is only an example of the present invention, and is not intended to limit the present invention.
FIG. 1 is a schematic view illustrating the structure of a VOC gas quantitative generator according to the present invention. As shown in FIG. 1, the gas quantitative generation device 10 covers a container 30 containing a volatile organic compound (VOC) 20 and an opening of the container 30 and diffuses a gas generated from the VOC to the outside of the container 30. A cap 40 having a diffusion port (not shown) to be used, and a diffusion filter 50 that covers the diffusion port of the cap 40 and controls the diffusion of gas, and the diffusion filter 50 is obtained by sintering polymer particles. It is a filter.

The volatile organic compound (VOC) applicable to the gas quantitative generator according to the present invention may be a general organic solvent having a high vapor pressure at normal temperature and a low boiling point at normal pressure, and is not particularly limited. It is not something. Specifically, hexane, 2,4-dimethyl pentane, heptane, octane, nonane, decane, and aliphatic compounds such as undecane. Moreover, aromatic compounds, such as benzene, toluene, ethylbenzene, xylene, styrene, and trimethylbenzene, are mentioned. Further, organic chlorine compounds such as chloroform, dichloroethane, trichloroethane, carbon tetrachloride, dichloropropane, trichloroethylene, tetrachloroethylene, chlorodibromomethane, and paradichlorobenzene can be given. Furthermore, as other compounds, like perfluoro dimethylcyclohexane, perfluoro methyl cyclohexane, hexafluorobenzene, octafluorotoluene, perfluoro lower Rirubenzen, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, butanol, pinene, and limonene etc. It is done.

Shape applicable container 30 to the device according to the invention, at least one of an opening may have any shape as long as it can accommodate the VOC, but the invention is not particularly limited. However, from the viewpoint of handleability, those having the shape of a bottle such as a vial are preferred. The container 30 is preferably formed of a material that is resistant to VOC and does not generate VOC from the container itself. Examples of such materials include glass, Teflon, and stainless steel.

  The shape of the cap 40 covering the opening of the container is not particularly limited as long as it has at least one diffusion port for diffusing VOC gas to the outside of the container and has an outer shape corresponding to the shape of the opening. It is not something. The cap 40 may have a shape that can be fitted into the opening of the container as shown in FIG. 1 or a shape that covers the upper surface of the opening. However, the cap is preferably formed of a material having excellent sealing properties so that VOC and VOC gas do not leak, and such materials include Teflon (registered trademark), Teflon (registered trademark) / silicone, and neoprene rubber. , And butyl rubber. Further, a sealing material such as an aluminum tape may be applied as necessary in order to enhance the sealing between the opening of the container and the cap.

  The diffusion port provided in the cap is not particularly limited, but the diameter is preferably about 0.3 mm to 50 mm, and more preferably about 2 mm to 20 mm. When the size of the diffusion port is 0.3 mm or less, it tends to be difficult to attach the diffusion filter. On the other hand, if the size of the diffusion port exceeds 50 mm, it tends to be difficult to control the amount of VOC gas generated by the diffusion filter.

The shape of the diffusion filter 50 is not particularly limited as long as it has an outer shape corresponding to the shape of the diffusion port provided in the cap 40. For example, the diffusion filter may have a shape that can be fitted into the diffusion port of the cap as shown in FIG. 1 or a shape that covers the upper surface of the diffusion port. However, the diffusion filter used in the present invention, a filter (hereinafter, referred to as "polymer particle sintered filter") obtained polymer particles by sintering must be. For example, when a thin film obtained by stretching and molding silicone or Teflon (registered trademark) is applied as a diffusion filter, it is difficult to quantitatively generate a very small amount of VOC gas because of a large variation in pore diameters in these filters.

Polymer particle sintered filter used in the present invention, according to methods well known in the art, the polymer particles and molded under heating after uniformly filled in a mold, and then can be easily manufactured by cooling It is. Regarding the method for producing the polymer particle sintered filter, it is possible to refer to, for example, JP 2001-171205 A and JP 2001-004609 A. Specific examples of the polymer particle sintered filter, polyethylene, polypropylene, polystyrene, polyester, and the like obtained by molding 1~500μm particles made of a resin such as a fluorine resin is sintered. Especially, the filter manufactured using the particle | grains of polyethylene or a polypropylene is preferable at the point that the shaping | molding of a filter is easy. Such polymer particles sintered filter since pore size is uniform, by using them as a diffusion filter, it is possible to accurately control the diffusion of the gas generated from the VOC.

Polymer particle sintered filter, size of the diffusion port of the cap, and it is preferable to mold in consideration of the diffusion of VOC. More specifically, the diameter is preferably about 0.3 mm to 50 mm, more preferably about 2 mm to 20 mm. When the size of the filter is 0.3 mm or less, the attachment to the diffusion port tends to be difficult. On the other hand, if the size of the filter exceeds 50 mm, it tends to be difficult to control the amount of VOC gas generated.

The thickness of the polymer particle sintered filter is preferably about 0.5 mm to 10 mm. When the thickness of the filter is thinner than 0.5 mm, it tends to be easily affected by the external environment such as wind during measurement. On the other hand, when the thickness of the filter exceeds 300 mm, there is a tendency that the variation in the hole diameter in the filter becomes large, which causes an error in measurement.
The pore diameter in the polymer particle sintered filter is preferably about 5 μm to 300 μm, more preferably about 10 μm to 200 μm, and further preferably about 20 μm to 100 μm. When the pore diameter of the filter is smaller than 5 μm, it is difficult to manufacture such a filter. On the other hand, if the pore diameter of the filter is larger than 300 μm, it tends to be easily affected by the external environment such as wind and humidity during measurement.

FIG. 2 is a schematic view illustrating another structure of the VOC gas quantitative generator according to the present invention. As shown in FIG. 2, the gas fixed quantity generator 10 includes a first container 30a that houses the VOC 20, a first cap 40a that covers the opening of the first container 30a, and the cap 40a. A guide pipe 60 that guides the generated gas to the outside of the first container 30a and a diffusion tower 70 having a diffusion filter 50 that controls the diffusion of the VOC gas guided by the guide pipe 60 are provided. It is the polymer particle sintered filter described in 1. above. The gas quantitative generator having such a structure is effective when it is desired to control the diffusion amount of the gas generated from the VOC to a very small amount, particularly when a diffusion rate of 20 mg / hour (h) or less is desired. is there. According to the present invention, for example, it is possible to control the rate of diffusion Hekisafu Luo Robenzen at 20 ° C. in the range of 0.01~0.50mg / h. In addition, the above-mentioned diffusion rate is a value obtained as a result of measuring weight loss due to gas generation every time.

The container applicable to the VOC gas quantitative generator according to the present invention is not particularly limited, and is as described above with reference to FIG. Further, the shape and material of the cap are as described above with reference to FIG. 1 except that the cap can be completely sealed without having a diffusion port.

  Referring to FIG. 2, the shape of the guide tube 60 is not particularly limited as long as it can penetrate the cap 40 a and guide the gas generated from the VOC to the outside of the first container 30 a. . Since it is excellent in handling and excellent in dimensional accuracy, it is preferable to apply a commercially available injection needle as a guide tube, and an injection needle having an inner diameter of about 0.15 mm to 4.00 mm is particularly preferable. When the inner diameter is smaller than 0.15 mm, the amount of gas generated becomes too small, and it tends to be difficult to achieve quantitative gas generation. On the other hand, if the inner diameter is thicker than 4.00 mm, it tends to be difficult to penetrate the needle through the cap. As a result, the cap may be damaged and gas leakage may occur, and the cap material piece may clog the needle tip, and it may be difficult to generate gas quantitatively. The length of the needle is adjusted in accordance with the size of the container and the amount of VOC accommodated in the container so that the tip of the needle is not immersed in the VOC liquid surface. If the tip of the needle is immersed in the VOC liquid level, VOC gas cannot be quantitatively generated.

Referring to FIG. 2, the VOC gas guided by the guide tube 60 is diffused to the outside through the diffusion tower 70 including the diffusion filter 50. The diffusion filter 50 is a polymer particle sintered filter and is the same as described above except that the diffusion filter 50 has a shape corresponding to the shape of the diffusion tower 70. The diffusion tower 70 is preferably formed in a cylindrical shape having a constant inner diameter, but the inner diameter and length are preferably adjusted as appropriate in consideration of the gas diffusion rate. Since the attachment to the guide tube 60 is simple, it is preferable to use a syringe having a protrusion at the tip as the diffusion tower. By inserting the injection needle into the protrusion of the syringe, the syringe can be easily fixed to the injection needle, and excellent sealing properties can be obtained. The diffusion filter may be attached to the diffusion tower after the induction tube and the diffusion tower are fixed, or may be previously performed before the induction tube and the diffusion tower are fixed.

FIG. 3 is a schematic view illustrating another structure of the VOC gas quantitative generation device according to the present invention. As shown in FIG. 3, the gas fixed quantity generator 10 has a second container 30b that substantially accommodates the gas fixed quantity generator described above with reference to FIG. That is, the guide tube 60 penetrating the first cap 40a covering the first container 30a continuously passes through the second cap 40b covering the opening of the second container 30b and is accommodated in the first container 30a. The gas generated from the generated VOC is guided to the outside of the second container 30b. The VOC gas guided to the outside of the second container 30b by the guide tube 60 is diffused to the outside of the apparatus through the diffusion tower 70 provided with the diffusion filter 50. In the gas fixed-quantity generating apparatus having such a structure, not only can the amount of gas generated be controlled to be smaller as in the apparatus shown in FIG. 2, but also the containers and It is possible to effectively prevent the gas leaked from the gap between the cap and between the guide tube and the cap from diffusing outside the apparatus. Further, by preventing such gas leakage, it is possible to quantitatively generate gas only from a predetermined position in an apparatus such as a diffusion tower.

  It should be noted that as the number of containers to be installed increases (the apparatus becomes more multi-layered), the leakage of VOC gas decreases, but the apparatus becomes bulky and heavy, and their movement becomes troublesome. Therefore, the number of containers to be added is preferably 2 to 3 (2 to 3 layers), and in view of practical use, it is desirable to have a double structure. When the apparatus has a multiple structure, the VOC is accommodated only in the innermost container, caps are provided in the openings of the containers, and guide tubes such as injection needles are passed through the caps. It should be noted that the tip of the needle must not be immersed in the liquid level of the VOC accommodated in the innermost container.

  As shown in FIGS. 2 and 3, in an apparatus having a guide tube penetrated through a cap that covers the opening of the container, a guide tube such as an injection needle may be pierced and penetrated immediately before the measurement. Therefore, it is not necessary for the operator to directly touch the VOC, and the apparatus can be easily installed without worrying about an operation error such as overflowing the VOC at the measurement place. Furthermore, the apparatus can be transported without a guide tube, and the VOC is sealed in the container. Therefore, the VOC does not wet the diffusion filter due to shaking or overturning during transportation, and gas can be generated quantitatively and accurately at any time.

As described above, according to the gas fixed quantity generator according to the present invention, a small amount of VOC gas can be obtained by using a polymer particle sintered filter as a diffusion filter without using a complicated device having a drive unit such as a pump. Can be generated quantitatively. In addition, it is possible to more precisely control the diffusion rate by generating VOC gas through the induction tube and the diffusion tower in addition to the diffusion filter. For example it is possible to control the rate of diffusion Hekisafu Luo Robenzen at 20 ° C. in the range of 0.01~0.50mg / h. Furthermore, problems such as undesired gas leakage and diffusion filter wetting can be remedied by having multiple containers in the apparatus.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to a following example, In the range which does not deviate from the summary of this invention, it can change variously.

Example 1
(1) Production of VOC quantitative generator The present example relates to a VOC gas quantitative generator having the multiple structure shown in FIG. First, 1 ml of hexafluorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) is injected into the inner container (2 ml brown crimp top vial made by Sperco), and a butyl rubber cap (Sperco stopper ( Product name)) covered. This inner container was inserted into an outer container (5 ml brown crimp top vial made by Spellco), and the opening of the outer container was covered with a cap made of butyl rubber (Stopper made by Spellco (trade name)) and sealed.
Next, to produce a diffusion tower by inserting inner diameter 5mm, sintered filter with a diameter of 5mm and a thickness of 2mm was obtained by sintering the polypropylene particles in the interior of the polyethylene syringes length 4 cm (pore size 50 [mu] m) . Next, an injection needle 20G “NN-2038R” (trade name) manufactured by Terumo Corp. was cut into a length of 3 cm as a guide tube, and fixed to the syringe protrusion of the diffusion tower prepared earlier. Finally, the device was completed by penetrating the caps of the outer container and the inner container with an injection needle to which the diffusion tower was fixed.

(2) Measurement of VOC gas diffusion rate VOC gas diffusion (generation) rate is measured in a laboratory set at a temperature of 20 ° C. by standing the VOC gas quantitative generator previously prepared and generating VOC gas. The weight loss of hexafluorobenzene accompanying the measurement was measured every 4 hours over 100 hours and plotted, and the slope was determined. As a result of such measurement, the diffusion rate is 0.176 mg / h, the correlation coefficient between time and weight loss is 0.999, with little variation, and a very small amount of VOC gas is generated quantitatively. I was able to confirm.

(Example 2)
A VOC gas quantitative generator was prepared in the same manner as in Example 1 except that an injection needle 18G “NN-1838R” (trade name) manufactured by Terumo Corporation was used as the guide tube. Using the produced apparatus, hexafluorobenzene was measured in the same manner as in Example 1. As a result, the gas diffusion rate was 0.32 mg / h, the correlation coefficient was 0.998, and a very small amount of VOC. It was confirmed that gas was generated quantitatively.

(Example 3)
A VOC gas quantitative generator was produced in the same manner as in Example 1 except that an injection needle 22G “NN-2232R” (trade name) manufactured by Terumo Corporation was used as the guide tube. Using the produced apparatus, hexafluorobenzene was measured in the same manner as in Example 1. As a result, the gas diffusion rate was 0.09 mg / h, the correlation coefficient was 0.999, and a very small amount of VOC. It was confirmed that gas was generated quantitatively.

(Comparative Example 1)
This comparative example relates to a conventional VOC gas generator by molecular diffusion. First, a 2 ml screw tube was used as a container, and 1 ml of hexafluorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) was injected into the container. Next, after covering the opening of the container with a silicone film made of Tokyo Glass Equipment having a diameter of 6 mm and a thickness of 2 mm as a diffusion filter, a polypropylene screw cap having an opening of 5.5 mm in the center is provided to seal the container. Thus, a VOC gas generator was produced. When the measurement was performed in the same manner as in Example 1 using the produced apparatus, the gas diffusion rate was 1.6 mg / h, and the correlation coefficient was 0.906. It was clear that the apparatus of Comparative Example 1 had a larger gas generation amount and a larger variation during measurement than the apparatus according to the present invention.

10: VOC gas quantitative generator 20: VOC
30, 30a, 30b: container 40, 40a, 40b: cap 50: diffusion filter (polymer particle sintered filter)
60: Guide tube 70: Diffusion tower

Claims (4)

A first container containing a volatile organic compound;
A cap covering the opening of the first container;
A guide tube that passes through the cap and guides the gas generated from the volatile organic compound to the outside of the first container;
A diffusion tower disposed outside the first container and having a diffusion filter for controlling diffusion of the gas guided by the induction tube, and the diffusion filter is obtained by sintering polymer particles. A gas quantification apparatus for volatile organic compounds characterized by being a filter.   The gas fixed-quantity generating apparatus according to claim 1, wherein a pore diameter of the sintered filter is in a range of 5 to 300 μm.   The apparatus further includes a second container that accommodates the entire first container, wherein the guide tube passes through a second cap that covers the opening of the second container, and the gas is placed outside the second container. The gas fixed-quantity generating apparatus according to claim 1, wherein the gas quantitative generation apparatus is guided.   The gas quantification generator according to any one of claims 1 to 3, wherein a diffusion rate of the gas is 0.01 to 0.50 mg / hour at 20 ° C.

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