JP7032200B2 - Local exhaust ventilation - Google Patents

Description

The present invention relates to a local exhaust system.

Conventionally, in the manufacturing process of highly pharmacologically active substances such as pharmaceuticals and drug substances, it is necessary to prevent exposure to workers and cross-contamination between products due to generation of chemical dust. Therefore, in the manufacturing process, a technique for containing chemical dust is applied.
When the highly pharmacologically active substance in a wet state is dried and recovered as a powder, a conical dryer having a slope with a lower center side at the bottom is used so that the recovery can be easily performed.

In the conical dryer, most of the dried powder slides down the slope and is collected in a collection container installed at the bottom. However, a part of it remains on the wall surface of the conical dryer, and it is difficult to recover it as it is.
Therefore, the operator scrapes the residual powder adhering to the wall surface from the opening at the top of the conical dryer to the container at the bottom by using, for example, a scraping jig with a long handle. At that time, it is necessary to provide a local exhaust facility so that the powder that has soared up at the upper opening of the conical dryer does not scatter to the operator and the working environment.

The local exhaust system is installed in or near the tank opening, sucks the generated dust together with the surrounding air, passes through the exhaust duct, passes through a precision filter such as a HEPA filter, removes the contained dust, and then the general exhaust system. It is common to join in. Appropriately designing local exhaust equipment and preventing dust from scattering into the work environment is important for work environment conservation and product quality control.

For example, Patent Document 1 discloses a semicircular local exhaust device attached to the upper part of a tank. Further, Patent Document 2 discloses a full-circle type local exhaust device.
In the local exhaust device of Patent Documents 1 and 2, a wind speed parallel to the opening surface is generated, and dust generated together with the surrounding air is sucked.

Japanese Patent No. 5576316 US62543430B1 Gazette

By the way, in the local exhaust device of Patent Document 1, the internal visibility can be improved and the workability can be improved by making it a semicircular shape. However, the air near the opening is more likely to be sucked in, and the wind speed decreases as the distance from the intake port increases. Therefore, the deficiency distribution becomes large, and it is necessary to inhale a large amount of air.

In the local exhaust device of Patent Document 2, a slit is provided in the side wall to suck air in the horizontal direction of the opening. However, the wind speed becomes uneven, and a large amount of wind is required to produce a predetermined wind speed at the center.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a local exhaust device capable of maintaining a required controlled wind speed while reducing an intake air volume.

In order to solve the above problems, the local exhaust device of the present invention is installed in the opening of a container that handles powder, and air passing through the inner cylinder flows into the container and is between the outer cylinder and the inner cylinder. It is discharged to the exhaust port through the arranged gap, and the outer cylinder has a guide cylinder having an outer diameter slightly smaller than the inner diameter of the opening at the lower end thereof, and the outer cylinder has the guide cylinder as the container. It is fitted into the opening of the container and placed on the container, and the opening at the lower end of the inner cylinder is arranged in the opening of the container with air flowing in from the entire region .

According to the present invention, it is possible to provide a local exhaust device capable of maintaining a required controlled wind speed while reducing the intake air volume.

The front sectional view schematically showing the air flow at the time of attaching the local exhaust device, the tank, and the local exhaust device according to the embodiment of the present invention. Schematic exploded cross-sectional view of the local exhaust device and tank of the embodiment. An exploded perspective view of the local exhaust device and the tank of the embodiment. Schematic cross-sectional view showing the process of assembling the local exhaust system to the tank. Schematic cross-sectional view showing the process of assembling the local exhaust system to the tank. Schematic cross-sectional view showing the process of assembling the local exhaust system to the tank. A perspective perspective view showing the assembled state of the local exhaust device and the exhaust flow path with a thick dashed arrow. Top view from above when the local exhaust system is installed on the tank. The figure which compares the exhaust air volume and the control wind speed with the local exhaust device of embodiment, and the whole circle type which sucks horizontally from the hole made on the conventional circumference and realizes the control wind speed. An exploded perspective view of a local exhaust device and a tank of a modified example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
These embodiments are suitable specific examples of the present invention and may be provided with various technically preferable limitations, but the technical scope of the present invention is the scope of the present invention unless otherwise specified to limit the present invention. It is not limited to these aspects.

FIG. 1 is a front sectional view schematically showing an air flow at the time of mounting the local exhaust device E, the tank 7, and the local exhaust device E according to the embodiment of the present invention.
When the highly pharmacologically active substance in a wet state is dried and recovered as a powder, for example, a conical dryer having a tank 7 having a slanted tank 7 having a lower center side at the bottom is used for easy recovery.

In the conical dryer, most of the dried powder slides down the inclined wall surface 7k of the tank 7 and is collected in a collection container (not shown) installed at the bottom. However, a part of the tank 7 remains on the inclined wall surface or the like, and it is difficult to recover the tank 7 as it is.

Therefore, the worker P uses something like a scraping jig 14 with a long handle from the opening 7o at the top of the tank 7 to remove the residual powder adhering to the inclined wall surface 7k or the like of the tank 7. Scratch into a collection container (not shown) provided at the bottom 7t.

At that time, the local exhaust device E of the embodiment is provided in the opening 7o at the upper part of the tank 7 so that the soared powder does not scatter to the worker P and the working environment.
The local exhaust device E of the embodiment is installed on the tank 7 via the packing 4.

FIG. 2 is a schematic exploded sectional view of the local exhaust device E and the tank 7 of the embodiment. FIG. 3 is an exploded perspective view of the local exhaust device E and the tank 7 of the embodiment.
The local exhaust device E includes an inner cylinder 1 and an outer cylinder 2.

For the inner cylinder 1 and the outer cylinder 2, a material having corrosion resistance, for example, stainless steel is used. As the material, another material may be used as long as it has corrosion resistance.
The inner cylinder 1 has an inner cylinder peripheral plate 1s and an inner cylinder upper plate 1u.

The inner cylinder peripheral plate 1s is formed in a cylindrical shape.
The inner cylinder upper plate 1u is an annular plate material extending outward from the upper edge of the inner cylinder peripheral plate 1s. A pair of inner cylinder handles 6 are installed on the inner cylinder upper plate 1u.

An annular packing 4a (see FIG. 2) is installed below the inner cylinder upper plate 1u. It should be noted that the packing 4a may not be used.
The outer cylinder 2 has an outer cylinder peripheral plate 2s, an outer cylinder upper plate 2o, an outer cylinder lower plate 2u, a guide cylinder 2a, and an exhaust duct connection portion 3.

The outer cylinder peripheral plate 2s is formed in a cylindrical shape having a diameter larger than the outer diameter of the inner cylinder peripheral plate 1s of the inner cylinder 1. As a result, a gap 2i (see FIG. 1) in an annular space is formed between the outer cylinder peripheral plate 2s of the outer cylinder 2 and the inner cylinder peripheral plate 1s of the inner cylinder 1.
An opening 2s1 (see FIG. 3) is formed in a part of the outer cylinder peripheral plate 2s. A cylindrical exhaust duct connection portion 3 which is an exhaust hole is connected to the opening 2s1.

The outer cylinder upper plate 2o is an annular plate extending inward from the upper edge of the outer cylinder peripheral plate 2s. A pair of outer cylinder handles 5 are mounted on the outer cylinder upper plate 2o. Since the inner diameter s2 of the opening 2o1 of the outer cylinder upper plate 2o is used for positioning the outer cylinder 2 and the inner cylinder 1, it is set to be slightly larger than the outer diameter s1 of the inner cylinder peripheral plate 1s of the inner cylinder 1.

As shown in FIG. 2, the outer cylinder lower plate 2u is an annular plate extending inward from the lower edge of the outer cylinder peripheral plate 2s.
The guide cylinder 2a has a tubular shape extending downward from the inner edge of the outer cylinder lower plate 2u. Since the outer diameter s3 of the guide cylinder 2a is used for positioning the outer cylinder 2 and the tank 7, it is set to be slightly smaller than the inner diameter s4 of the opening 7o of the tank 7.

An annular packing 4 is installed at the connection portion between the outer cylinder lower plate 2u and the guide cylinder 2a. The packings 4 and 4a are made of silicone rubber, EPDM rubber (Ethylene propylen diene rubber) or the like.
It should be noted that the packing 4 may not be used.

With the above configuration, an intake hole Ei (see FIG. 1) is formed in the lower portion between the inner cylinder peripheral plate 1s of the inner cylinder 1 and the outer cylinder peripheral plate 2s of the outer cylinder 2 over the entire circumference. The air taken in from the intake hole Ei is sucked into the gap 2i between the outer cylinder 2 and the inner cylinder 1.

As shown in FIG. 1, the exhaust system is connected to the exhaust duct connection portion 3 of the outer cylinder 2.
As an exhaust system, a HEPA filter 9 is attached upstream of the exhaust fan 10. An exhaust system 11 such as an exhaust duct is connected to the downstream of the exhaust fan 10.

The exhaust duct connection portion 3 of the outer cylinder 2 is connected to the HEPA filter 9 via the exhaust duct 8. That is, the exhaust duct 8 connected to the HEPA filter 9 and the exhaust duct connection portion 3 of the outer cylinder 2 are connected.
The above-mentioned local exhaust device E is used as follows.

By operating the exhaust fan 10, as shown in FIG. 1, air flows in from the outside through the opening surface 1o of the inner cylinder 1 (arrow α11 in FIG. 1).
The inflowing air is sucked from the intake hole Ei together with the powder generated inside the tank 7 and is taken into the gap 2i formed between the inner cylinder 1 and the outer cylinder 2. The taken-in air passes through the gap 2i (arrow α13 in FIG. 1), passes through the exhaust duct connection portion 3, and is discharged to the exhaust duct 8 (arrow α14 in FIG. 1). Then, the inflowing air is discharged together with the powder through the exhaust duct 8 (arrow α15 in FIG. 1).

At this time, as shown in FIG. 1, almost all of the exhausted air is the air that has passed through the inner cylinder 1 in the vertical direction (arrow α11 in FIG. 1). The lower portion of the inner cylinder 1 is located below the height of the opening surface 7o1 of the opening 7o of the tank 7. As a result, the wind direction is made uniform at the height position of the opening surface 7o1 of the tank 7.

As a result, the powder generated inside the tank 7 cannot rise against the air entering the inner cylinder 1 (arrow α11 in FIG. 1), but flows in from the annular intake hole Ei to enter the inner cylinder 1 and the outer cylinder. It is exhausted through the gap 2i between 2 and through the exhaust duct connection portion 3 and the exhaust duct 8 (arrow α15 in FIG. 1). Therefore, it is possible to prevent the worker P from being exposed to the powder as much as possible.

The assembly of the local exhaust device E as an example to the tank 7 is performed as follows.

4 to 6 are schematic cross-sectional views showing a process of assembling the local exhaust device E to the tank 7. In FIGS. 4 to 6, the worker P is omitted.

As shown in FIG. 4, the worker P attaches the packing 4 to the outer cylinder 2. At this time, an adhesive may or may not be used.
The operator P grips the outer cylinder handle 5 and lifts the outer cylinder 2, inserts the guide cylinder 2a of the outer cylinder 2 into the opening 7o of the tank 7, and places the outer cylinder 2 on the opening 7o of the tank 7. Place (see Fig. 5).

Then, as shown in FIG. 6, the worker P grips the inner cylinder handle 6 and lifts the inner cylinder 1, and the inner cylinder peripheral plate 1s of the inner cylinder 1 is placed on the opening 7o of the tank 7. It is fitted into the opening 2o1 of the outer cylinder upper plate 2o of the cylinder 2 and the inner cylinder 1 is placed on the outer cylinder 2 on the tank 7 (see FIG. 7).

A gap 2i in an annular space is formed between the inner cylinder 1 and the outer cylinder 2. FIG. 7 is a perspective perspective view showing the assembled state of the local exhaust device E and the exhaust flow path with a thick broken line arrow. In FIG. 7, the air flow is shown by a thick broken line.
As a result, the local exhaust device E is installed in the opening 7o of the tank 7. Then, as shown in FIG. 1, the exhaust duct connection portion 3 of the outer cylinder 2 and the exhaust duct 8 to which the HEPA filter 9 or the like is connected are connected.

FIG. 1 shows an example in which the inner cylinder 1 and the outer cylinder 2 can be disassembled. The outer cylinder handle 5 and the inner cylinder handle 6 are shown in order to improve operability when each of them is installed, but the presence or absence of the handle is not limited and is arbitrary.
Further, the case where the inner cylinder 1 and the outer cylinder 2 are made of separate members is shown, in order to improve the cleanability of the inner cylinder 1 and the outer cylinder 2. On the other hand, an integrated structure in which the inner cylinder 1 and the outer cylinder 2 are fixed may be used.

<Exhaust air volume and control air speed in exhaust fan 10>
FIG. 8 is a top view seen from above when the local exhaust device E is installed on the tank 7. 8 (1) to (4) show the measurement points of the wind speed.

With the configuration shown in FIG. 1, the wind speed distribution at the position of the opening surface 1o of the inner cylinder 1 was measured when the exhaust air volume of the exhaust fan 10 was set to 4.02 m ³ / min.
As shown in FIG. 8, Table 1 shows the results of measuring the control wind speed at each of the measurement points (1) to (4) by dividing the opening surface 1o into four (1) to (4). The controlled wind speed is the wind speed at the opening surface 1o.

Among the measurement points (1) to (4), the maximum was 0.90 m / s in (1) and the minimum was 0.76 m / s in (3). The difference is 0.14 m / s. The average of the wind speed measured values at the measurement points (1) to (4) was 0.80 m / s.
Therefore, almost the same controlled wind speeds were obtained at all the measurement points (1) to (4) on the opening surface 1o of the inner cylinder 1.

FIG. 9 shows the exhaust air volume and control of the local exhaust device E of the embodiment and the full circular type that sucks horizontally from a hole (corresponding to the opening surface 1o) formed on the conventional circumference and realizes a controlled wind speed. It is a figure which compares the wind speed. The horizontal axis shows the exhaust air volume (m ³ / min), and the vertical axis shows the control wind speed (m / s). The exhaust air volume is the air volume of the exhaust fan (corresponding to the exhaust fan 10).

The conventional all-circle type (for example, Patent Document 2) ready-made product requires an exhaust air volume of about 19 m ³ / min (cubic meter per second) in order to realize a controlled wind speed of 0.5 m / s (meters per second). be.
On the other hand, in the local exhaust device E of the embodiment, 4 m ³ / min is sufficient to realize a controlled wind speed of 0.8 m / s.

Therefore, it was confirmed that the local exhaust device E of the embodiment can significantly reduce the exhaust air volume of the exhaust fan 10.
It was confirmed that if the wind speed on the opening surface 1o of the inner cylinder 1 is 0.1 m / s or more, the leakage of powder from the container 7 can be suppressed. That is, if the wind speed at the opening surface 1o is 0.1 m / s or more, the backflow of powder from the container 7 can be suppressed.

According to the local exhaust device E having the above configuration, since the air is once sucked into the tank 7, the worker P can suppress the sucking of the substance in the tank 7 as much as possible.
Further, the exhaust air volume of the exhaust fan 10 can be reduced.

Further, since the intake hole Ei of the local exhaust device E is formed over the entire circumference of the opening 7o of the tank 7, the unevenness of the air sucked in the opening 7o is reduced.
Further, since the local exhaust device E is divided into the inner cylinder 1 and the outer cylinder 2, cleaning is easy. Further, since the inner cylinder 1 and the outer cylinder 2 are separated, it is lightweight and easy to handle.

Further, by installing the packing 4, air leakage from between the container 7 and the outer cylinder 2 can be suppressed. In addition, the use of the packing 4 prevents the outer cylinder 2 and the tank 7 from being damaged.
Similarly, by installing the packing 4a, air leakage from between the inner cylinder 1 and the outer cylinder 2 can be suppressed. In addition, the use of the packing 4a prevents the outer cylinder 2 and the inner cylinder 1 from being damaged.

Therefore, it is possible to provide the local exhaust device E capable of maintaining the required controlled air velocity while reducing the intake air volume (exhaust air volume).

<< Modification example >>
FIG. 10 is an exploded perspective view of the local exhaust device 2E and the tank 7 of the modified example.
The local exhaust device 2E of the modified example has a configuration in which the inner cylinder upper plate 1u of the inner cylinder 1 of the embodiment is widely formed as shown by reference numeral 21u in FIG. 10 and the outer cylinder upper plate 2o of the outer cylinder 2 is eliminated. be.

Since other configurations are the same as those in the embodiment, they are indicated by reference numerals in the 20s, and detailed description thereof will be omitted as appropriate.
The local exhaust device 2E of the modified example includes an inner cylinder 21, an outer cylinder 22, and a packing 24.
The inner cylinder 21 has an inner cylinder peripheral plate 21s and an inner cylinder upper wide plate 21u.

The inner cylinder peripheral plate 21s is formed in a cylindrical shape.
The inner cylinder upper wide plate 21u is an annular plate that widely extends outward from the upper edge of the inner cylinder peripheral plate 21s. The outer diameter s5 of the inner cylinder upper wide plate 21u is set to be the same as or larger than the outer diameter s6 of the outer cylinder 22. A pair of inner cylinder handles 26 are mounted on the inner cylinder upper wide plate 21.

The outer cylinder 22 has an outer cylinder peripheral plate 22s, an outer cylinder lower plate 22u, a guide cylinder 22a, and an exhaust duct connecting portion 23.
The outer cylinder peripheral plate 22s is formed in a cylindrical shape having a diameter larger than the outer diameter of the inner cylinder peripheral plate 21s of the inner cylinder 21. A gap 22i, which is an annular space, is formed between the inner cylinder peripheral plate 21s of the inner cylinder 21 and the outer cylinder peripheral plate 22s of the outer cylinder 22.

An opening 22s1 is formed in a part of the outer cylinder peripheral plate 22s. A cylindrical exhaust duct connection portion 23 is connected to the opening 22s1.
An outer cylinder handle 25 is attached to the outer cylinder peripheral plate 22s.

The outer cylinder lower plate 22u is an annular plate extending inward from the lower edge of the outer cylinder peripheral plate 22s.
The guide cylinder 22a has a tubular shape extending downward from the inner edge of the outer cylinder lower plate 22u. The outer diameter s7 of the guide cylinder 22a is set to be slightly smaller than the inner diameter s8 of the opening 7o of the tank 7.

An annular packing 24 is installed at the connection point between the outer cylinder lower plate 22u and the guide cylinder 22a. The packing 24 may not be used.
Assembling the local exhaust device 2E is performed after the guide cylinder 22a of the outer cylinder 22 is inserted into the opening 7o of the tank 7 and the outer cylinder 22 provided with the annular packing 24 is placed in the opening 7o of the tank 7, as in the embodiment. The cylinder 21 is placed on the outer cylinder 22.

That is, the worker P holds the outer cylinder 22 by grasping the outer cylinder handle 25 provided with the packing 24, inserts the guide cylinder 22a of the outer cylinder 22 into the opening 7o of the tank 7, and inserts the outer cylinder 22 into the tank. It is placed in the opening 7o of 7.
Then, the worker P holds the inner cylinder 1 by grasping the inner cylinder handle 26, and the inner cylinder peripheral plate 21s of the inner cylinder 21 is placed on the opening 7o of the tank 7 to be placed on the outer cylinder circumference of the outer cylinder 22. It is inserted inside the plate 22s, and the inner cylinder 21 is placed on the outer cylinder 22. An annular space gap 22i is formed between the inner cylinder 21 and the outer cylinder 22.

According to the modified example, since the outer cylinder upper plate (see reference numeral 2o in FIGS. 2 and 3) of the outer cylinder 22 is not provided, the inside of the outer cylinder peripheral plate 22s can be easily cleaned. Therefore, the outer cylinder 22 is easy to clean, and the local exhaust device 2E is excellent in cleanability.
Further, since the inner cylinder 21 and the outer cylinder 22 are separated, it is lightweight and has good workability.

<< Other Embodiments >>
1. 1. In the above embodiment, the case where the intake holes Ei of the local exhaust device E are continuously formed on the entire circumference of the inlet of the tank 7 is illustrated, but the intake holes Ei may be discontinuous in some places. By forming the intake hole Ei over the entire circumference of the inlet of the tank 7, a nearly uniform controlled wind speed can be obtained.

2. 2. In the above embodiment, the case where the local exhaust device E is composed of the inner cylinders 1 and 21 and the outer cylinders 2 and 22 is illustrated, but if the intake hole Ei is inside the tank 7, another configuration is adopted. May be good.

3. 3. In the above embodiment, the case where the packings 4, 4a (24, 24a) are provided is exemplified, but the packing 4 (24) or the packing 4a (24a) may be provided alone.

4. The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. It is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is also possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1,21 Inner cylinder 1o, 21o Opening surface (opening)
1u Inner cylinder upper plate (upper plate)
2,22 Outer cylinder 2i, 22i Gap (gap)
2o Outer cylinder upper plate (upper plate)
3,23 Exhaust duct connection part (exhaust port)
4, 24, 4a, 24a Packing (seal material)
7 Container 7o Opening (entrance of container)
21u Inner cylinder upper wide plate (upper plate)
E, 2E Local exhaust device Ei Intake hole

Claims (8)

Installed in the opening of a container that handles powder,
The air passing through the inner cylinder flows into the container, passes through the gap arranged between the outer cylinder and the inner cylinder, and is discharged to the exhaust port.
The outer cylinder has a guide cylinder at the lower end thereof having an outer diameter slightly smaller than the inner diameter of the opening.
In the outer cylinder, the guide cylinder is fitted into the opening of the container and placed on the container, and the outer cylinder is placed on the container.
The opening at the lower end of the inner cylinder is arranged in the opening of the container with air flowing in from the entire area.
A local exhaust system characterized by that. In the local exhaust device according to claim 1,
The outer cylinder is installed in the opening of the container for handling powder, has the exhaust port, and has the exhaust port.
The inner cylinder is installed inside the outer cylinder with the gap between the inner cylinder and the outer cylinder.
An upper plate provided between the outer cylinder and the inner cylinder and closing the opposite side of the container in the gap,
A local exhaust device that is arranged in the container and is provided with an intake hole in which air that has flowed into the container from the outside flows into the container and flows into the gap. In the local exhaust device according to claim 1,
A local exhaust device characterized in that the outer cylinder and the inner cylinder have a divided structure. In the local exhaust device according to claim 1,
A local exhaust device characterized in that the controlled wind speed at the upper opening of the inner cylinder of the air flowing into the container is 0.1 m / s or more. In the local exhaust device according to claim 1,
A local exhaust device characterized in that a sealing material is provided at least between the outer cylinder and the container or between the outer cylinder and the inner cylinder. In the local exhaust device according to claim 1,
The outer cylinder and the inner cylinder have a divided structure.
A local exhaust device characterized by having an upper plate provided on the inner cylinder without being provided on the outer cylinder. In the local exhaust device according to claim 1,
A local exhaust device characterized in that an intake hole into which air outside the container flows is arranged inside the container. In the local exhaust device according to claim 7,
The local exhaust device is characterized in that the intake hole is provided over the entire circumference of the inlet of the container.

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