JPH085688Y2 - Inhalation toxicity test equipment - Google Patents

Description

[Detailed description of the device]

[0001]

This invention relates to a device for conducting an inhalation toxicity test of pesticides, drugs, etc. on small animals such as rats, and more particularly to a device for inhaling dust and mist containing a test substance by head exposure. is there.

[0002]

2. Description of the Related Art Generally, an inhalation toxicity test is carried out by using a mist prepared by dispersing a liquid test substance such as an agricultural chemical in a gas such as air in a mist state or a dust prepared by dispersing a powder of a solid test substance in a gas. It is used for inhalation in small animals such as rats, and the toxicity of the test substance is evaluated by the biological damage caused by the inhalation. A typical inhalation toxicity test is an acute inhalation toxicity test. In this acute inhalation toxicity test, the toxicity of the test substance is usually evaluated by the concentration at which half of the test animals die when exposed for a certain period of time (that is, the half-lethal concentration LC ₅₀ ).

In the above-mentioned inhalation toxicity test, test substances such as mist and dust reach the lungs from the nasal cavity or oral cavity of the test animal via the respiratory tract (trachea / bronchi). Therefore, the inhaled substance will also be deposited in the nasal cavity other than the lungs, the oral cavity or the respiratory tract. The deposition rate for each of these sites varies significantly depending on the particle size, especially when the inhaled substance is a particulate substance such as mist or dust, and generally large particles have a deposition rate for the nasal cavity or oral cavity. Is extremely large, and therefore the rate of reaching the lungs and depositing in the lungs is significantly small, whereas the deposition rate in the nasal cavity and oral cavity is smaller for particles with a certain size or more, and reaches the lungs and deposits in alveoli. The percentage is high. On the other hand, even if the same substance is inhaled, the effect of the substance on the living body differs depending on the deposited site. Therefore, even if the test substance of the same concentration is inhaled, if the particle size is different, the degree and content of the damage actually suffered by the test animal will be different. Therefore, even if the above-mentioned acute inhalation toxicity test is performed using the same test substance, the half-lethal concentration values shown as the experimental results will differ depending on the size and variation of the particle size, and conversely half Even if the lethal concentration values are the same, the true evaluation of the toxicity of the test substance should differ depending on the size of the particle size and the degree of variation. For these reasons, in order to perform a correct toxicity evaluation in an inhalation toxicity test, particularly in an inhalation toxicity test with mist or dust, the mist or dust to be inhaled by the test animal must have a predetermined systematic particle size distribution, A very important point is to have a uniform particle size distribution that does not contain unexpectedly coarse particles.

The inhalation toxicity test method includes a whole body exposure method in which the whole body of a small animal such as a rat is exposed to an atmosphere containing a test substance in an inhalation box (chamber), and an atmosphere in the inhalation box only in the head or nose. There is a head exposure method in which the test substance is exposed to the skin, but in the former systemic exposure method, the test substance is dermally administered in addition to inhalation by the respiratory system. Exposure method is preferred.

As shown in FIG. 4, a conventional inhalation toxicity test apparatus for head exposure has a hollow cylinder-shaped vertical inhalation box main body 1 having a peripheral wall portion of an inhalation toxicity test apparatus. Multiple openings 2 for exposing the head or nose
Are formed at intervals in the circumferential direction, holders 4 for holding a test animal 3 such as a rat are attached to these openings 2 respectively, and a test for mist or the like is performed on the upper end 1A of the inhalation box body 1. A supply device for supplying a substance, for example, a spray nozzle 5 for spraying a liquid test substance to generate a mist is provided, and a gas containing the test substance such as a mist is blown from the upper side to the lower side in the suction box body 1. It is widely known to send to.

However, in such a conventional apparatus, it is difficult to make the particle size distribution uniform, and variations in particle size are liable to occur, and the variations are not constant in many cases. The particles collide with each other until they are inhaled, and the particles agglomerate due to contact with each other to generate coarse particles.As a result, the animals to be tested include mist with unexpectedly large coarse particles. There is a problem that it will be inhaled and thus it will be difficult to make a correct toxicity evaluation. It is also conceivable that a mist or the like having a uniform particle size distribution is brought to the upper end 1A of the inhalation box body 1 in advance by a classifier or the like, but even in that case, it is inhaled from the upper end of the inhalation box body 1 into the test animal 3. In the meantime, the problem of particle agglomeration is unavoidable, and even if the classification is performed, agglomeration occurs even before the particle is guided from the classifier to the upper end of the suction box body 1, and even in that case, unexpectedly large particles are generated. Preventing inhalation of particles has been difficult.

Therefore, the inventors of the present invention, as a device for inhalation toxicity test using a mist in which a liquid test substance is dispersed in a gas in a mist state among various test substances, have a certain particle size distribution excluding unexpected coarse particles. A test device for inhalation toxicity which enables a test animal to be inhaled with a mist having an inhalation, thereby enabling accurate toxicity evaluation, has already been disclosed in Japanese Examined Patent Publication No.
-45574.

An inhalation box (chamber) of the above proposed inhalation toxicity test apparatus is shown in FIG.

In FIG. 5, the suction box body 10 is formed so as to have a hollow cylindrical shape as a whole, and an upper end portion thereof has a conical surface 11. A mist discharge port 13 communicating with the hollow chamber 12 in the suction box body 10 is formed at the top of the suction box body 10.

Further, the peripheral wall of the suction box body 10 is
The openings 2, 2'to which the holder 4 for holding the test animal 3 such as a rat is attached, that is, the openings 2, 2'for exposing the head of the test animal 3 are circumferentially spaced. Moreover, it is formed in two steps, upper and lower. A supply chamber 1 provided with a test liquid mist supply device, for example, a spray nozzle 14 for generating the test liquid mist, at the lower end of the suction box body 10.
5 is formed in a state partitioned with respect to the hollow chamber 12 in the suction box body 10. That is, the atomizing nozzle 14 is attached upward in the center of the bottom of the supply chamber 15, and a small hole-shaped ejection port 16 is vertically formed at the top of the supply chamber 15. .

Further, in the hollow chamber 12 of the main body 10 of the suction box, the hollow chamber 12 is provided at a position directly above the ejection port 16.
A disc-shaped collision plate 17 having a diameter smaller than the inner diameter of the is arranged horizontally. The collision plate 17 is arranged at a small distance upward with respect to the upper opening end of the ejection port 16 and has a plurality of support arms protruding inward from the inner peripheral wall of the suction box body 10. The collision plate 17 is mounted and supported on the tip end of the collision plate 18, so that the collision plate 17 is substantially open at its periphery. On the collision plate 17, a hollow space body 19 having a shape substantially similar to the suction box body 10 and smaller than the suction box body 10 is placed. Therefore, in the hollow chamber 12 inside the suction box body 10, the central portion of the space above the collision plate 17 is occupied by the space body 19.

In the inhalation toxicity test apparatus for mist as described above, if compressed air and a test solution are supplied to the atomizing nozzle 14, the supply chamber 1 goes upward from the nozzle 14.
5, the test liquid mist is sprayed, the test liquid mist rises in the supply chamber 15 and is converged at the ejection port 16, and the accelerated mist passes through the ejection port 16 and moves upward from the ejection port 16 at high speed. And it collides with the collision plate 17. Therefore, the test liquid mist is classified by the inertial collision with the collision plate 17. That is, the coarse particles in the mist ejected from the ejection port 16 collide with the collision plate 17 to be adhered and aggregated to the collision plate 17, and become droplets and fall from the collision plate 17 under its own weight. On the other hand, mist particles of a certain size or smaller in the mist ejected from the ejection port 16 pass from the lower surface side of the collision plate 17 to the periphery thereof and occupy the inner peripheral surface of the suction box body 10 in the hollow chamber 12. Ascends in the space between the body 19 and reaches the openings 2, 2'and is inhaled by the animal 3 to be tested,
Further, the mist which has not been inhaled by the animal 3 to be tested is discharged from the mist discharge port 13 to the outside of the apparatus by an appropriate exhaust means.

Here, even in the mist composed of the relatively fine particles classified by the inertial collision with the collision plate 17 as described above, the particles agglomerate due to the mutual collision of the particles until reaching the openings 2 and 2 '. Coarse particles may be generated, and the coarse particles may be mixed in the collision plate 17 due to re-scattering. However, since the mist must rise from the collision plate 17 to the openings 2 and 2 ', coarse particles generated by agglomeration and the like settle according to Stokes' settling law, and as a result, the openings are actually formed. The particles reaching 2,2 'are limited to those having a particle size of a certain size or less. Therefore, in the above-mentioned device, the classification effect due to the inertial collision and the sedimentation effect due to Stokes' law are combined, and the inhalation of coarse particles into the test animal is extremely effectively prevented.

[0014]

[Problems to be solved by the invention] Depending on the purpose of the inhalation toxicity test and the type of test substance, the particle size of the mist or dust to be inhaled by the test animal (actually the maximum particle size)
May want to change.

By the way, in the case of the apparatus shown in FIG. 5, the classification effect by inertial collision and the effect by Stokes's settling law are utilized in order to cause the test animal to inhale only particles having a target particle size or less. ing. Regarding the classification effect due to the inertia collision, the degree of classification is changed by changing the diameter of the nozzle 14 and / or the distance between the nozzle 14 and the collision plate 17 shown in FIG. The particle size reaching the space between the stack 19 can be changed. On the other hand, the effect of Stokes' settling law changes depending on the rising velocity of the mist. For example, if the velocity is increased, particles of relatively large diameter will also rise to the inhalation site in the hollow chamber and be inhaled by the test animal. . Therefore, as described above, in order to change the maximum diameter of mist particles to be inhaled by the test animal, change the nozzle diameter or the distance between the nozzle and the collision plate to change the classification effect due to inertial collision, or to eject from the nozzle. It is considered that the flow rate of mist supplied into the hollow chamber may be changed to change the rising velocity of the mist in the hollow chamber.

However, of the classification effects due to inertial collision and the effects due to Stokes's settling law as described above, the classification effect due to inertial collision is effective for mist particles but not for dust particles. . Therefore, when using dust, the Stokes' settling law must be used exclusively, and in order to change the maximum particle size of the dust inhaled by the test animal, the rising velocity of dust in the hollow chamber must be adjusted. I have no choice but to change.

On the other hand, in the case of mist, the classification effect by inertial collision can be utilized as described above, but in this case, it is necessary to improve the dimensional accuracy of the nozzle diameter and also the accuracy of the distance between the nozzle and the collision plate. In addition, it is necessary to make the flatness of the collision plate highly accurate, and therefore it is necessary to sufficiently improve the processing accuracy and mounting accuracy of each component.
Inevitably, the equipment cost will increase. Therefore, also in the case of mist, from the viewpoint of cost, it may be considered that the classification effect due to inertial collision is not positively used, and only Stokes' settling law is used.
In the case of the above-mentioned relatively large particles, classification can be performed using only Stokes' settling law without using the classification effect due to inertial collision. Even if you use the classification effect of inertia collision for mist,
It is often difficult to accurately change the nozzle diameter and the distance between the nozzle and the collision plate as expected in order to change the maximum particle diameter of the mist inhaled by the test animal. From these points, therefore, even when using a mist, in order to change the maximum particle size of the mist to be inhaled by the test animal, it is necessary to apply a method of changing the flow rate of the mist supplied from the nozzle into the hollow chamber. Considered appropriate.

However, in an actual inhalation toxicity test apparatus, if the flow rate of mist or dust ejected from the nozzle is changed, the apparatus becomes complicated and the cost becomes high. That is, in the inhalation toxicity test device, it is necessary to avoid leakage of toxic test mist and dust from the inside of the inhalation box body. It is necessary to maintain a negative pressure, but in order to maintain a slight negative pressure in the hollow chamber at all times even if the supply amount of mist or dust changes, the control system becomes complicated and costly. I will end up.

Further, in general, in order to generate high-concentration dust and mist in a sufficiently uniformly dispersed state, it is necessary to maintain a certain amount of air supply to the dust generator and the mist generator, and therefore, the dust is required. In many cases, it is practically difficult to change the maximum particle size to be inhaled by the animal under test according to Stokes' settling law by changing the amount of mist or mist supplied.

As described above, by changing the flow rate of mist or dust supplied to the hollow chamber, the rising velocity of the mist or dust in the hollow chamber is changed to change the maximum diameter of particles reaching the suction site. Was conventionally difficult to apply in practice.

The present invention has been made in view of the above circumstances. Basically, in an inhalation toxicity test apparatus in which a mist or dust containing a test substance is made to flow upward from below the hollow chamber in the main body of the inhalation box. By changing the rising velocity of mist or dust near the inhalation site with a simple and inexpensive structure without changing the supply flow rate of mist or dust, the maximum diameter of particles to be inhaled by the test animal can be changed. It is an object of the present invention to provide such a device.

[0022]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention basically provides an inner peripheral wall of a hollow chamber in a vertical suction box body having a hollow cylindrical shape with a space in the circumferential direction. In the device for performing an inhalation toxicity test by placing an opening and placing the head or nose of the test animal in the opening and supplying dust or mist of the test substance to the hollow chamber, A supply device for supplying dust or mist to the lower end of the chamber is provided,
A discharge port for discharging dust or mist is formed at the upper end of the hollow chamber, and the central portion of the hollow chamber has a shape that is almost similar to the inner shape of the hollow chamber and that is smaller than the inner diameter of the hollow chamber. The body is detachably disposed, and dust or mist is supplied upward from the supply device into the hollow chamber, and at the same time, dust or mist in the hollow chamber is discharged from the discharge port to collect the dust or mist. It is configured to raise the annular flow path between the outer peripheral surface of the body and the inner peripheral surface of the hollow chamber, and further, as the occupying body, a plurality of different outer diameters are provided, and It is characterized in that the flow velocity of dust or mist rising in the annular flow path is changed by changing the occupying bodies to be arranged to have different diameters.

[0023]

In the device for inhalation toxicity test of the present invention, the dust or mist is discharged from the discharge port at the same time as the dust or mist is supplied upward from the supply device below the hollow chamber. Flowing from the lower side to the upper side in the chamber, and particularly in the portion where the occupying body is located, the annular flow path between the outer peripheral surface of the occupying body and the inner peripheral surface of the hollow chamber rises. Then, dust or mist is inhaled by the animal under test at the opening part in the middle of the ascent. Here, when dust or mist rises in the hollow chamber, Stokes' settling law acts, and coarse particles reach a certain height depending on the flow velocity and settle, resulting in the opening portion. Only the particles having a certain diameter or smaller according to the flow velocity will reach the position, ie, the inhalation site by the test animal.

Here, since a plurality of occupying bodies having different outer diameters are provided, if the occupying bodies arranged in the hollow chamber are replaced with those having different diameters, the outer peripheral surface of the occupying body and the hollow body are hollow. The flow path cross-sectional area (flow path area in the horizontal cross section) of the annular flow path between the inner peripheral surface and the inner peripheral surface changes. Therefore, even if the flow rate of dust or mist supplied to the hollow chamber is constant, the flow rate of dust or mist rising in the annular flow path changes. As a result, according to Stokes' law of sedimentation, the maximum particle size reaching the inhalation site (the position of the opening) changes, and the maximum particle size of dust or mist inhaled by the test animal also changes.

[0025]

1 to 3 show an inhalation toxicity test apparatus according to an embodiment of the present invention. The inhalation toxicity test apparatus of this example is for using dust in which powder of a solid substance is dispersed in gas (usually air).

In FIGS. 1 and 2, the suction box main body 20 has a hollow cylindrical shape as a whole, and has an upper portion formed in a conical shape. Specifically, the inhalation box body 20 has a configuration in which a conical upper lid portion 21, a hollow cylindrical body portion 22, and a bottomed short cylindrical bottom portion 23 are vertically and detachably connected. Has been done. The connecting means between them is arbitrary, but in the illustrated example, the flange portion 21 is used.
Packing 24 between A, 22A, 22B and 23A
And the flanges are connected by bolts and nuts 25.

At the center of the lower bottom surface of the suction box body 20, that is, at the center of the lower surface of the bottom portion 23, a nozzle 26 is provided as a supply device for ejecting dust upward, and the position at which the nozzle 26 is disposed. Around the nozzle 26
A cylindrical guide tube 27 that surrounds the upper space of the is provided. In addition, a discharge hole 23B for discharging the settled dust powder is formed in the peripheral portion of the lower surface of the bottom portion 23. On the other hand, a discharge port 28 is formed at the top of the upper lid portion 21, and a discharge path 29 is integrally formed above the discharge port 28. Further, the discharge path 29 has an exhaust process (not shown). A discharge pipe 30 for guiding dust to a device and a suction pump is connected via a connector 31. Further, in the discharge passage 29, a hollow chamber 35 in the suction box body 20 is provided.
A leak valve 41 having a leak hole 41 </ b> A for maintaining the internal pressure of the device at an appropriate slight negative pressure is provided.

Further, a peripheral wall of an intermediate portion of the suction box body 20,
That is, the test animal 3 such as a rat is provided on the peripheral wall of the body 22.
A plurality of openings 33A, 33B to which a holder 34 for holding 2 is attached, that is, a plurality of openings 33A, 33B for exposing the head of the animal 32 to be tested are circumferentially spaced apart and vertically arranged in two stages. Is formed in. FIG. 1
In order to simplify the drawing, the upper opening 33A and the lower opening 33B are shown aligned vertically, but in reality, as shown in FIG. 2, the position of the upper opening 33A and the lower opening 33A are shown. It is desirable to shift the position of the opening 33B in the circumferential direction.

Further, in the hollow chamber 35 in the main body 20 of the suction box, an occupant 36A having a shape substantially similar to that of the hollow chamber 35 and having a diameter smaller than that of the hollow chamber 35 is the same as the axial center position of the hollow chamber 35. It is arranged so as to be at the axial center position. That is, the occupying body 36A is formed in a hollow shape in which the upper end of the bottomed cylindrical body is closed by a conical surface, and the occupying body 36A is formed of a plurality of inwardly projecting portions from the lower peripheral wall of the suction box body 20. It is placed and supported across the tip of the book support arm 37. Here, the upper surface of the tip of each support arm 37 is notched in a stepped shape, and the notch 37a forms a positioning edge surface 37 that forms a vertical edge surface at a position apart from the tip of the support arm by a predetermined distance.
b is formed. On the other hand, a stepped portion (or cutout portion) 36a is also formed in the peripheral portion of the bottom surface of the space body 36A corresponding to the cutout portion 37a of each support arm 37.
A has a restriction surface 36b that contacts the positioning edge surface 37b of the support arm 37.

As the occupying body, a plurality of types (three in the example of FIG. 3) 36A, 36B, 36C having different outer diameters Ra, Rb, Rc are prepared in advance as shown in FIG. A selected one of these (36 A in the illustrated example) is disposed in the hollow chamber 35.

The opening 33 in the hollow chamber 35
An acceleration collecting plate 38 is horizontally arranged at a position directly above A and 33B. The accelerated collection plate 38 has a large number of small holes 39 vertically penetrating the plate surface and formed with a uniform distribution density. And this acceleration collecting plate 38 is
Is formed in a donut disk shape so as to close the dust flow path between the outer peripheral surface of the suction chamber main body 20 and the inner peripheral surface of the hollow chamber 35 (the inner peripheral surface of the suction chamber main body 20). It is placed and supported by a plurality of support protrusions 40 protruding inward from the inner peripheral wall of the upper end of the. As the acceleration collecting plate 38, a plurality of types having the inner diameters corresponding to the outer diameters of the occupying bodies 36A to 36C are prepared in advance.

In the inhalation toxicity test apparatus of the above-mentioned embodiment, the dust in which the powder of the solid test substance is dispersed in the gas (usually air) is ejected from the nozzle 26, and the exhaust pipe 30 is exhausted through the exhaust treatment apparatus. When the connected suction pump (not shown) is operated, the dust ejected from the nozzle 26 is discharged from the guide cylinder 27 to the inner peripheral surface of the hollow chamber 35 and the outer peripheral surface of the occupying body 36A by the negative pressure from the discharge port 28. Ascends through the annular space (flow path) 42 between the two. During this time,
The coarse particles in the dust settle according to the flow velocity according to Stokes' settling law, so that only particles having a certain size or less that do not include coarse particles reach the positions of the openings 33A and 33B, that is, the inhalation site of the test animal. , Which will be inhaled by the test animal 32.

The dust that has passed through the inhalation site of the animal to be tested and has reached the vicinity of the acceleration collection plate 38 is larger in number than the acceleration collection plate 38 as compared with the flow passage cross-sectional area of the hollow portion around the space body 36A. Due to the small total flow passage cross-sectional area of the small holes 39, the flow velocity rapidly increases and passes through each small hole 39 of the accelerated collection plate 38 from below. At this time, due to the rapid increase in the flow velocity as described above, the particles in the space below the acceleration collection plate 38 flow so as to be attracted to each small hole 39, and therefore the dust is collected on the lower surface of the acceleration collection plate 38. The particles are unlikely to adhere. Immediately after exiting upward from each small hole 39 of the acceleration collection plate 38, on the contrary, the flow velocity sharply decreases and the flow direction diffuses.
The particles coarsened by mixing and agglomeration while passing through the small holes settle and fall around the small holes 39 on the acceleration collection plate 38, and the remaining minute particles are discharged from the discharge port 28 to the discharge passage 29 and the discharge pipe. Three
After passing through 0, the exhaust gas is guided to an exhaust treatment device (not shown). Further, at a position above the acceleration collecting plate 38, the suction box body 20
Once adheres to the inner wall surface of the container or the inner surface of the discharge port 28, and aggregates,
After that, the coarse particles that have re-fallen also fall on the acceleration collection plate 38. Therefore, it is possible to effectively prevent these coarse particles from reaching the inhalation site of the test animal, and thus inhaling these coarse particles into the test animal 32.

Here, the inner peripheral surface of the hollow body 35 and the space body 36
The annular flow path 42 between the outer peripheral surface of A and the flow path area is determined by the outer diameter of the space body. Therefore, if the occupying body 36B (see FIG. 3) having a smaller outer diameter Rb is used instead of the occupying body 36A, the flow passage cross-sectional area of the annular flow passage 42 is increased, and therefore the nozzle 26 is supplied. Even if the flow rate of dust is the same, the flow velocity of dust that rises in the annular flow path 42 becomes small, and as a result, the maximum particle size of dust that reaches the inhalation position by the animal 32 to be tested becomes small according to Stokes' law of sedimentation. . On the other hand, on the contrary,
If the space body 36C having a larger outer diameter Rc is used,
Since the flow passage cross-sectional area of the annular flow passage 42 becomes small, the flow velocity of the dust rising in the annular flow passage 42 becomes large even with the same dust supply flow rate, and as a result, the maximum particle size of the dust reaching the suction site becomes large on the contrary. .

In the embodiment, each occupying body 36A-3
The position of 6C is such that the restriction surface 36b at the bottom and the support arm
7 is determined by the positioning edge surface 37b, and therefore, even when the occupying bodies 36A to 36C are exchanged, it is necessary to easily arrange them so that the axis of the occupying body coincides with the axial center position of the hollow chamber 35. You can

Furthermore, in the above-mentioned embodiments, the inhalation toxicity test device using dust was explained, but also in the case of the inhalation toxicity test device for mist, a plurality of space bodies having different outer diameters are prepared. In addition, it is possible to achieve the same effect as the above by appropriately replacing the same. In this case, the acceleration collecting plate 38 in the apparatus shown in FIG. 1 is removed, and the nozzle 26 in FIG.
Can be used as an inhalation toxicity test device for mist simply by changing the one for mist ejection.

[0037]

As is apparent from the above description, according to the inhalation toxicity test apparatus of the present invention, a plurality of space bodies having different outer diameters are provided, and the space bodies arranged in the hollow chamber are different. By exchanging with an outer diameter, even if the flow rate of dust or mist supplied to the hollow chamber is the same, it is possible to change the flow rate of the dust or mist in the annular flow path to the inhalation site by the test animal, Therefore, the maximum particle of dust or mist inhaled by the test animal can be changed with a simple and easy structure. Further, in the inhalation toxicity test apparatus of the present invention, it is not necessary to change the supply flow rate of dust or mist into the hollow chamber even when changing the maximum particle size of dust or mist to be inhaled by the test animal. It is possible to effectively prevent an adverse effect caused by the change, for example, a situation in which it becomes difficult to uniformly disperse particles in dust or mist.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an inhalation toxicity test apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional plan view taken along line XX of FIG.

3 is a partially omitted vertical sectional view showing a plurality of occupying bodies prepared for the apparatus of FIG.

FIG. 4 is a schematic diagram showing a general inhalation toxicity test device by a conventional head exposure method.

FIG. 5 is a vertical cross-sectional view showing an inhalation toxicity test device previously proposed by the present inventor.

[Explanation of symbols]

 20 Inhalation Box Main Body 26 Nozzle 28 Discharge Port 32 Animal Under Test 33A, 33B Opening 35 Hollow Chamber 36A, 36B, 36C Stacking Body 42 Annular Channel

Claims (1)

[Scope of utility model registration request] 1. An opening is formed in the inner peripheral wall of a hollow chamber in a vertical inhalation box body having a hollow cylindrical shape at intervals in the circumferential direction, and the head or nose of the animal under test is formed in the opening. And an apparatus for performing an inhalation toxicity test by supplying dust or mist of a test substance to the hollow chamber, while providing a supply device for supplying dust or mist to the lower end side of the hollow chamber, the hollow chamber Form a discharge port for discharging dust or mist at the upper end of
Further, in the center of the hollow chamber, a space body having a shape substantially similar to the inner shape of the hollow chamber and having a diameter smaller than the inner diameter of the hollow chamber is detachably arranged, and the space is directed upward from the supply device into the hollow chamber. At the same time as supplying dust or mist, the dust in the hollow chamber is discharged from the discharge port to raise the dust or mist in the annular flow path between the outer peripheral surface of the space body and the inner peripheral surface of the hollow chamber. In addition, a plurality of occupants having different outer diameters are provided in advance,
An inhalation toxicity test device, characterized in that the flow velocity of dust or mist rising in the annular flow passage is changed by changing the occupying bodies arranged in the hollow chamber to have different diameters.