JP2009103616A - Airflow control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure, rectify air contacting a sample within a chamber, and substantially uniformize a flow velocity of air in the entire area of the contact portion of the sample. <P>SOLUTION: An airflow control unit 10 has a body 11, and a sample holder 12 detachably attached to the body 11, and internally holding the sample S. The body 11 has an upper duct 15 and a lower duct 16 having an air suction port E1 and an air discharge port E2, and a fan 23 for generating an airflow from the suction port E1 to the discharge port E2. The upper duct 15 has a sample window 28 opened so as to cause internally-flowing air to contact the sample S. The lower duct 16 has a partition 36 internally disposed so as to bypass the airflow from the sample window 28 to the fan 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air flow control unit used in a test for evaluating chemical performance of building materials by bringing a sample made of building materials into contact with air of a predetermined flow, and more specifically, air contacts. The present invention relates to an airflow control unit capable of making the air flow rate substantially uniform in the entire region of a sample.

  Building materials such as building boards, wallpaper, carpets, construction adhesives, and paints placed in buildings dissipate harmful substances such as volatile organic compounds, formaldehyde, and carbonyl compounds, depending on the type. May cause indoor air pollution that causes the syndrome.

  Therefore, it is important to evaluate the various building materials by experimentally investigating the amount of harmful substances released from the building materials used before the construction of the building. As one of such test evaluation methods, a chemical substance emission test called “JIS A 1901 small chamber method” which is standardized by JIS is known. In this test, a building material sample to be evaluated is housed in a container called a chamber, air at a predetermined flow rate is supplied into the chamber, and harmful substances are collected from the air that has passed through the chamber. By doing so, the state of emission of harmful substances from the sample is specified.

  As a chamber applied to the chemical substance emission test, a chamber having a fan that controls the flow rate of the air to a specified value by stirring the air inside is known (for example, see Patent Document 1). . As shown in FIG. 6, the chamber 50 includes a cylindrical main body 51 in which the upper end is opened and the sample S is accommodated therein, a lid 52 that is detachable on the upper end side of the main body 51, and the main body 51. A disk-like plate 53 in which a large number of through holes 53A are formed, and a fan 55 arranged in a space in the main body 51 below the plate 53. It has. In the chemical substance emission test using the chamber 50, the sample S held in a holder (not shown) is placed on the plate 53, and external air is introduced into the main body 51 from the air introduction unit 57 at a specified flow rate. Is done. The air in the main body 51 contacts the sample S at a predetermined flow rate by the rotation of the fan 55, and is discharged from the air discharge unit 58 to the outside of the chamber 50 after a predetermined time. Then, the content of harmful substances with respect to the exhaust air is measured using an analytical instrument or the like.

By the way, as another test method for evaluating the chemical performance of building materials, a chemical substance adsorption test called “JIS A 1905-1 Reduction performance test method of indoor air pollution concentration reducing material by small chamber method” was conducted in February 2007. It was enacted. The chemical adsorption test is a test performed on a building material that absorbs a chemical substance in the air (hereinafter referred to as “pollutant”) that causes indoor air pollution, and a sample of the building material. The adsorption performance of the building material is evaluated by measuring the adsorption rate of a predetermined pollutant at. In this test, similar to the chemical emission test described above, air is introduced from the outside into the chamber containing the sample, and contaminants are collected from the air that has passed through the chamber. This is different from the chemical emission test in that a predetermined amount of pollutant is mixed in the air.
JP 2007-12995 A

  However, according to the results of experiments conducted by the present inventors, when the chemical substance adsorption test is performed using the chamber having the structure of Patent Document 1, the sample surface is one of the conditions defined by JIS. It became clear that it was difficult to ensure the uniformity of the air flow velocity passing through. That is, in the chemical substance emission test of “JIS A 1901”, it is considered that the water vapor conversion substance transmission rate is preferably 9 to 18 m / s, which means that the flow velocity of air passing through the sample surface is 0.1 m / s to 0. This corresponds to 3 m / s. However, in the chemical substance adsorption test of “JIS A 1905-1”, the water vapor conversion substance transmission rate is regulated to 15 ± 3 m / s, which means that the flow velocity of air passing through the sample surface is 0.25 ± 0.05 m. / S. In other words, in the chemical substance emission test of “JIS A 1901”, if the variation in the air flow velocity on the sample surface is 0.2 m / s or less, it conforms to the regulations, but the chemical of “JIS A 1905-1” In the substance adsorption test, the variation must be 0.05 m / s or less, and in this respect, the conditions are stricter than the chemical substance emission test of “JIS A 1901”.

  Therefore, as will be described later, the present inventors conducted an experiment to measure the flow velocity distribution of air in contact with the sample surface using the chamber 50 having a capacity of 20 L having the structure shown in FIG. As a result, the flow velocity of air between predetermined measurement points in the sample surface has a maximum difference of 0.21 m / s. In the chamber 50 having the structure of FIG. 6, the chemistry of “JIS A 1905-1” It cannot be applied to the substance adsorption test. This variation is considered to be caused by the turbulent flow such as the swirling flow generated in the air in the chamber 50 due to the rotation of the fan 55 and the turbulent flow affecting the air flow in the vicinity of the sample S. For this reason, in order to reduce the variation, it is necessary to make the air flow distance between the sample S and the fan 55 as long as possible. However, when a 20 L chamber defined by JIS is used, its height is about 50 cm, and the structure of the chamber 50 makes it difficult to secure the flow distance sufficient to reduce the variation.

  The present invention has been devised by paying attention to such problems, and its purpose is to rectify the air in contact with the sample in the chamber with a simple structure, and to adjust the flow rate of the air to the contact portion of the sample. It is an object to provide an airflow control unit that can be made substantially uniform over the entire area.

(1) In order to achieve the above object, the present invention is an air flow control unit used in a test for evaluating a chemical performance of a sample by bringing the sample into contact with a predetermined flow of air,
A sample installation section in which the sample is installed, an air inlet and an outlet of the air, a wind tunnel portion provided with an air flow path connecting the inlet and the outlet, and the inlet to the outlet A flow generating means for generating a flow of air in the flow path,
The wind tunnel part includes a sample window facing the sample installed in the sample installation part, and a partition member provided in the middle of the flow path between the flow generation means and the sample window,
The sample window is opened so that air flowing through the flow path can come into contact with the sample,
The partition member is configured to be disposed so as to bypass the air flow between the flow generation means and the sample window.

  (2) Moreover, it is preferable to take the structure that the sample holder which hold | maintains the said sample in the state which exposed at least one part of the said sample is installed in the said sample installation part.

  According to the configuration of (1) above, when the airflow control unit of the present invention is installed in an existing chamber and a chemical substance adsorption test is performed, the air between the flow generating means and the sample window is caused by the presence of the partition member. The flow distance can be increased as compared with the prior art. For this reason, the flow of air in contact with the sample is not easily affected by the turbulent flow generated by the flow generation means, and the air in contact with the sample can be rectified with a simple structure that eliminates the need for complicated control equipment. The flow velocity of the air can be made substantially uniform over the entire area of the sample in contact with the air. Further, by changing the state of the flow generating means, it is possible to adjust the flow velocity of the air that contacts the sample, and it is possible to obtain a flow velocity that conforms to various test standards. Furthermore, with a smaller device configuration, the influence of turbulent flow by the flow generating means can be reduced and the air contacting the sample can be rectified, making it applicable to a chamber with a small volume and limited height. .

  By configuring as in (2) above, an existing sample holder that can be used in other chemical performance evaluation tests such as building materials can be used as it is.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing an airflow control unit according to the present embodiment together with a chamber, and FIG. 2 is a partially exploded perspective view of the airflow control unit. 3 is a schematic cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a schematic cross-sectional view taken along line BB in FIG. In these figures, the airflow control unit 10 of the present embodiment is used for a chemical substance adsorption test defined in “JIS A 1905-1”, and is a block-shaped block made of a building material to be tested. The sample S is held in the internal space of the cylindrical chamber C while being held. The chamber C includes a cover C1 that is detachable so that the open portion on the upper end side can be opened and closed. With the cover C1 removed, the air flow control unit 10 is set in the chamber C, The test is performed with the body C1 attached. At the time of this test, a prescribed flow rate of air containing contaminants is introduced into the chamber C from an air introduction part C2 formed in the lower part of the chamber C. As will be described later, the air in the chamber C is introduced into the airflow control unit 10 and comes into contact with the sample S, and then discharged from the airflow control unit 10 into the chamber C. And after predetermined time progress, the air in the chamber C is discharged | emitted outside the chamber C from the air discharge part C3 formed in the cover body C1. The exhausted air is measured for the residual amount of contaminants using a device (not shown), and the adsorption performance of the contaminants on the sample S is evaluated.

  The airflow control unit 10 includes a main body 11 through which air in the chamber C passes, and a box-shaped sample holder 12 that is detachably attached to two side portions of the main body 11 and holds the sample S therein. It is prepared for.

  The main body 11 includes an upper duct 15 and a lower duct 16 that form a hollow wind tunnel portion in which an air flow path is formed, an installation plate 18 having a substantially rectangular shape in plan view installed at the bottom of the chamber C, A leg body 20 that stands up from four corner portions of the installation plate 18 and supports the upper duct 15 and the lower duct 16 and a fan 23 (see FIGS. 3 and 4) that is fixed substantially at the center of the installation plate 18. It is prepared for. The main body 11 is formed of a material that does not dissipate pollutants and does not easily adsorb chemical substances diffused from the sample S, such as fluororesin and stainless steel, and can be cleaned by heat desorption. .

  The upper duct 15 is formed in a gate shape whose upper end is open (see FIG. 2). Specifically, the upper duct 15 includes a pair of opposing plates 25 and 25 that face the sample holders 12 and 12 and end plates 27 and 27 that are continuous between both ends of the opposing plates 25 and 25, respectively. Yes. The open part formed at the upper end of the upper duct 15 is a suction port E1 for introducing the air in the chamber C into the main body 11, and the inner space of the upper duct 15 is for the air from the suction port E1 to be sent to the lower duct. This is a first flow path F1 (see FIG. 3) that leads to the interior of 16.

  Each of the counter plates 25 is formed in a downward U shape, and the inner open portion thereof is a sample in the sample holder 12 from the first flow path F1 when the sample holders 12 and 12 are attached to the main body 11. A sample window 28 facing S is formed. The sample window 28 is formed so that the air flowing through the first flow path F1 can come into contact with a partial surface of the sample S.

  The lower duct 16 is connected to the lower end side of the upper duct 15, the top wall 31 extending horizontally from the lower end side of each of the opposing plates 25, 25 along the installation plate 18, and the lower end side and the apex of the end plate 27. A side wall 32 that hangs downward from the peripheral side of the wall 31, a bottom wall 35 fixed to the inner surface of the side wall 32 so as to bisect a space formed inside the side wall 32, and a position above the bottom wall 35. A fixed partition plate 36 (partition member) is provided.

  The top surface of the top wall 31 is an installation surface (sample installation part) where the sample holders 12 and 12 are installed upright. Although not shown, a member for restricting the movement of the sample holders 12 and 12 in the direction along the installation surface protrudes from the installation surface.

  As shown in FIGS. 3 and 4, the space above the bottom wall 35 among the spaces formed inside the side wall 32 is a second continuous with the first flow path F <b> 1 in the upper duct 15. It becomes the flow path F2.

  The bottom wall 35 has a substantially rectangular plate shape in plan view, and a round hole-like discharge port E2 penetrating vertically is formed at a substantially central portion thereof.

  As shown in FIGS. 2 to 4, the partition plate 36 has a size in which the length in the short width direction is shorter than the bottom wall 35, while the length in the longitudinal direction is the same. Yes. Therefore, as shown in FIG. 3, the partition plate 36 has the gaps A <b> 1 between the left and right side walls 32, 32 formed on both left and right side sides in the same figure, and both side walls 32 in the direction orthogonal to the paper surface in FIG. , 32 (see FIG. 4).

  The leg 20 has an upper end fixed to the lower surface of the bottom wall 35, and a lower end fixed to the upper surface of the installation plate 18. The leg portion 20 is set to a length that allows the space A <b> 2 to be formed between the upper surface side of the installation plate 18 and the lower end side of the side wall 32.

  The fan 23 is disposed below the bottom wall 35 so as to face the discharge port E2, and functions as a flow generating unit that generates a flow of air from the suction port E1 to the discharge port E2. The fan 23 is provided such that its rotational speed is variable, and since the flow velocity on the sample window 28 corresponding to the rotational speed is obtained in advance through experiments or the like, by adjusting the rotational speed, The flow rate of the air that contacts the sample S can be set to a desired value.

  As shown in FIG. 2, each sample holder 12 includes a box-shaped container 41 in which the sample S is accommodated, and a lid 42 that is detachably provided on the container 41. ing.

  The container 41 includes a side wall 45 and a frame-like bottom wall 47 continuous to one end side of the side wall 45, and an open part formed on the opposite side of the bottom wall 47 serves as a sample S in / out part. The part can be opened and closed by the lid 42.

  The bottom wall 47 is formed with a square hole 47A through which the sample S accommodated inside the container 41 is exposed. The square hole 47A faces the sample window 28 of the main body 11, and the sample holder 12 is set in the main body 11. At this time, the sample window 28 is closed by the sample holder 12, and the air passing through the first flow path F 1 does not leak from the sample window 28 to the outside of the air flow control unit 10. The surface of the sample S located inside can be contacted.

  In the airflow control unit 10, air flows as follows.

  When the fan 23 rotates, the air in the chamber C is guided from the suction port E1 on the upper end side of the main body 11 to the first flow path F1 in the upper duct 15 as indicated by the arrow in FIG. 16 reaches the second flow path F2. Then, the air in the second flow path F2 flows from substantially the center of the space above the partition plate 36 toward the left and right ends in FIG. 3 and passes through the gap A1 to the space below the partition plate 36. It sinks and passes through the discharge port E <b> 2 at the approximate center of the space and is discharged from the space A <b> 2 between the legs 20 to the outside of the airflow control unit 10.

The present inventors conducted an experiment for demonstrating the effect of the airflow control unit 10 configured as described above. In this experiment, the volume of the chamber C is 20 L, the ventilation condition of the chamber C is 0.5 times per hour, and as shown in FIG. The air flow velocity at the nine measurement points P was measured using a sensor (not shown). This measurement was performed for two types of rotations of the fan 23: 500 rpm and 700 rpm. The results are shown in the following table.

On the other hand, as a comparative example, the flow velocity of the air passing through each measurement point P was measured for the sample S installed in the chamber 50 having the conventional structure shown in FIG. 6 under the same experimental conditions as described above. The results are shown in the following table.

  When comparing the above tables, it can be clearly seen that the airflow control unit 10 according to the present embodiment has a higher effect of suppressing variation in the air flow velocity between the measurement points P.

  That is, when the airflow control unit 10 according to the present embodiment is used, when the rotational speed of the fan 23 is 500 rpm, the variation in the flow velocity between the measurement points P is 0.05 m / s at the maximum, and each measurement point at the same 700 rpm. The maximum flow rate variation between P is 0.06 m / s.

  However, when the sample S is installed in the conventional chamber 50 according to the comparative example, when the rotational speed of the fan 55 is 500 rpm, the variation in the flow velocity between the measurement points P is 0.17 m / s at the maximum and 700 rpm at the same. The maximum variation in the flow velocity between the measurement points P is 0.21 m / s, and the variation in the air flow velocity in the surface of the sample S is larger than when the airflow control unit 10 of the present embodiment is used. .

  Therefore, according to the present embodiment, it is possible to reduce the variation in the air flow velocity over the entire surface of the sample S with a simple structure.

  That is, in the airflow control unit 10 of the present embodiment, since the partition plate 36 is provided in the second flow path F2, the flow of air from the first flow path F1 toward the exhaust port E2 is changed to the exhaust port E2. It detours in the direction away from the center and forcibly bulges outward from the second flow path F2. For this reason, when there is no partition plate 36, the flow of air that linearly descends from the first flow path F1 to the exhaust port E2 is blocked by the partition plate 36, so that the second flow path F2 The moving distance of the air at is greater than that without the partition plate 36. As a result, the air flow distance from the sample S to the fan 23 is increased as compared with the conventional case, and the air contacting the sample S is rectified by being less affected by the turbulent flow in the vicinity of the fan 23. It is considered that the flow velocity of the air is almost uniform over the entire surface of the sample S. Therefore, even when a sufficient linear separation distance between the fan 23 and the sample S cannot be secured as in the case where the 20 L small chamber C is used, the airflow control unit 10 allows the air flowing from the sample S to the fan 23 to flow. The influence of the fan 23 can be reduced as much as possible by increasing the distance, and the air in contact with the sample S can be rectified.

  The flow generating means is not limited to the fan 23, and can be replaced with another device such as a pump as long as the air flow from the suction port E1 to the discharge port E2 can be generated. Further, the installation position of the flow generating means may be on the suction port E1 side or in the first and second flow paths F1 and F2 as long as the air rectification state is not disturbed.

  Further, as described above, as long as the partition plate 36 can rectify the air in contact with the sample S by bypassing the air flow between the flow generating means and the sample window 28, the partition plate 36 is in contrast to the embodiment. It is also possible to change the arrangement or substitute a partition member having a different shape other than the plate shape.

  Furthermore, the sample holder 12 of the present embodiment may be the one used in other conventional tests. Further, the sample holder 12 can be omitted and the sample S can be directly set on the main body 11 by covering the sample S with a predetermined film except for the portion of the sample S facing the sample window 28. . In the above-described embodiment, the sample S is attached to the main body 11 at two places. However, the sample S may be attached to the main body 11 at least one place, and the number is not limited.

  Moreover, although the said embodiment demonstrated the example which used the airflow control unit 10 for the chemical substance adsorption test prescribed | regulated to "JISA1905-1", the airflow control unit 10 of this invention is used for the use. It is not limited. For example, the unit 10 of the present invention can be applied to an adsorption rate measurement using a formaldehyde-dissipating building material defined in “JIS A 1905-2”, which is a similar chemical substance adsorption test. In addition, since the flow rate of the air contacting the sample S can be set to a desired value by adjusting the rotation speed of the fan 23, the unit 10 of the present invention is a chemical substance emission test defined in “JIS A 1901”. It can also be used when other tests such as the test specified in “ISO 16000-9” are performed. In short, the present invention can be applied to all evaluation tests of the chemical performance of the sample S in which the flow velocity of the air contacting the sample S must be controlled and the flow velocity distribution of the air contacting the sample S must be uniform.

  In addition, the configuration of each part of the apparatus in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same operation is achieved.

The schematic perspective view which showed the airflow control unit which concerns on this embodiment with the chamber. FIG. 3 is a partially exploded perspective view of the airflow control unit. The schematic sectional drawing which follows the AA line in FIG. The schematic sectional drawing which follows the BB line in FIG. The schematic front view of the sample holder for demonstrating the measurement point in the sample in verification experiment. The schematic sectional drawing of the conventional chamber.

Explanation of symbols

10 Air Flow Control Unit 11 Body 12 Sample Holder 15 Upper Duct (Wind Tunnel)
16 Lower duct (wind tunnel)
23 Fan (flow generation means)
28 Sample window 31 Top wall (Sample installation part)
36 Partition plate (partition member)
E1 Intake port E2 Discharge port F1 First channel F2 Second channel S Sample

Claims (2)

An airflow control unit used in a test for evaluating a chemical performance of a sample by bringing the sample into contact with a predetermined flow of air,
A sample installation section in which the sample is installed, an air inlet and an outlet of the air, a wind tunnel portion provided with an air flow path connecting the inlet and the outlet, and the inlet to the outlet A flow generating means for generating a flow of air in the flow path,
The wind tunnel part includes a sample window facing the sample installed in the sample installation part, and a partition member provided in the middle of the flow path between the flow generation means and the sample window,
The sample window is open so that air flowing through the flow path can come into contact with the sample,
The air flow control unit, wherein the partition member is disposed so as to bypass the air flow between the flow generation means and the sample window.   The airflow control unit according to claim 1, wherein a sample holder that holds the sample in a state where at least a part of the sample is exposed is installed in the sample installation unit.

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