JP7036590B2 - Biohazard countermeasure cabinet - Google Patents

Description

The present invention relates to a biohazard countermeasure cabinet (hereinafter, simply referred to as "cabinet") that forms a work area maintained in a clean environment.

Conventionally, for example, a cabinet as disclosed in Patent Document 1 has been put into practical use. Such a cabinet has a blower. By this blower, air, gas generated in the work area, pollutants and the like (hereinafter, these are collectively referred to as "gas") are sucked from the work area. A part of the sucked gas passes through the filter to become clean gas, and then is supplied to the work area again. The other part of the sucked gas passes through the filter to become clean gas, and then is discharged to the outside of the cabinet.

Noise is generated from the cabinet due to the operation of the blower and the flow of gas. Naturally, the smaller this noise is, the better. For example, JIS K3800: 2009 stipulates that the noise level at a predetermined position should be 67 dB or less.

Japanese Patent No. 40968886

The present invention has been made in view of such a situation, and an object of the present invention is to reduce noise generated from a cabinet.

The biohazard countermeasure cabinet according to the present invention is a biohazard countermeasure cabinet in which a work area is arranged, and is installed in an upper space arranged vertically above the work area and in the vertical direction. It comprises a blower having a bell mouth having a frame portion surrounding an upwardly facing suction port, and a shielding plate fixedly installed in the upper space and above the blower.

According to the present invention, the noise generated from the cabinet can be reduced.

Front view of the cabinet. FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG. Perspective view of the plenum unit. Front view of the plenum unit. FIG. 6 is a schematic cross-sectional view taken along the line VV in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the side facing the worker using the cabinet is the front side, and the opposite side is the back side. In addition, the right side is the right side when viewed from the worker on the front side, and the opposite side is the left side.

FIG. 1 is a front view of a cabinet 1 according to an embodiment of the present invention. The cabinet 1 includes a cabinet body 10 and a pedestal 20 that supports the cabinet body 10.

Inside the cabinet body 10, a work area A for performing various experimental operations and the like is arranged. The work area A is surrounded by the housing 11 on three sides, the back side, the right side, and the left side, and the front side is surrounded by the shutter 12. The shutter 12 can be opened and closed.

On the upper front side of the housing 11, a lighting 13 for illuminating the hands of a worker who works in the work area A is installed.

On the upper side of the lighting 13, a control panel 14 in which various buttons and the like are arranged for operating the cabinet 1 is installed.

FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG. The housing 11 has a double wall on the lower side and the back side of the work area A.

The lower double wall of the work area A constitutes the lower duct D1 through which gas flows. The lower duct D1 is arranged substantially horizontally and extends so as to allow gas to flow from the front side to the back side. A front side gas suction port H1 is provided on the lower side and the front side of the housing 11 and facing the work area A. The front gas suction port H1 is a port for sucking gas into the lower duct D1 from the inside of the work area A and from the outside of the work area A through the opening of the shutter 12. An amount of air corresponding to the amount of gas discharged from the cabinet 1 via the exhaust portion described later is sucked into the lower duct D1 from the outside of the work area A.

The double wall on the back side of the work area A (the first flat plate member 111 and the fifth flat plate member 115 described later) constitutes the back side duct D2 through which gas flows. The back side duct D2 is arranged substantially vertically and extends so as to allow gas to flow from the bottom to the top. Back side gas suction for sucking gas from the work area A to the back side duct D2 on the lower side and the back side of the housing 11 facing the work area A (lower part of the fifth flat plate member 115). The mouth H2 is provided.

The lower duct D1 and the back duct D2 are connected to each other to form a substantially L-shaped side view duct.

A straightening vane 15 having a large number of through holes is installed above the work area A in the vertical direction, that is, directly above. The straightening vane 15 also serves as a ceiling plate of the work area A.

The plenum unit 30 is installed inside the housing 11 above the straightening vane 15 in the vertical direction, that is, directly above, that is, directly above the work area A.

The plenum unit 30 is sandwiched between the first flat plate member 111 on the back side and the third flat plate member 113 on the front side, which constitute the housing 11, in the front-rear direction. Further, a second flat plate member 112 and a fourth flat plate member 114 are attached to the right side and the left side of the plenum unit 30, respectively (see FIGS. 3 and 5). The first flat plate member 111, the second flat plate member 112, the third flat plate member 113, and the fourth flat plate member 114 are arranged in order in a clockwise direction in a plan view. The upper end position of the fifth flat plate member 115 is lower than the upper end position of the first flat plate member 111.

Therefore, a space surrounded by the first flat plate member 111, the second flat plate member 112, the third flat plate member 113, and the fourth flat plate member 114 on the front, back, left, and right sides exists directly above the work area A. Hereinafter, this space will be referred to as an upper space S.

As described above, in the present embodiment, the first flat plate member 111 and the third flat plate member 113 are members constituting the housing 11, and the second flat plate member 112 and the fourth flat plate member 114 will be described later. It is a member constituting the plenum unit 30. However, each flat plate member arranged on the right side and the left side of the upper space S may be a member constituting the plenum unit 30, and each flat plate member arranged on the back side and the front side of the upper space S may be a member. It may be a member constituting the plenum unit 30.

The plenum unit 30 includes a blower 31, a bell mouth 32, a box body 33, an air supply filter 34, an exhaust filter 35, and the like.

The blower 31 has a vertical rotation shaft and a plurality of blades provided around the rotation shaft. The blower 31 has a suction port on the upper surface. A bell mouth 32, which is a rectifying member, is attached to the upper side of the blower 31 so as to cover the suction port. The shape of the bell mouth 32 will be described later.

The shape of the bell mouth 32 itself is not limited to the one shown in the figure as long as the blower 31 can appropriately suck gas from the suction port, and a rectifying member different from the bell mouth 32 may be attached. .. Further, the bell mouth 32 or other rectifying member may be integrally formed on the blower 31.

The discharge port of the blower 31 is provided on the side of the blower 31 and is surrounded by the box body 33.

An air supply filter 34 made of, for example, a HEPA filter is arranged at the bottom of the box body 33. The lower surface of the air supply filter 34 faces the straightening vane 15.

Further, an exhaust filter 35 made of, for example, a HEPA filter is connected to the box 33 via an exhaust duct 37 and an exhaust box 38, which will be described later.

3 and 4 are a perspective view and a front view of the plenum unit 30, respectively. FIG. 5 is a schematic cross-sectional view taken along the line VV in FIG.

The plenum unit 30 has a frame body 36. The blower 31, the box body 33, the air supply filter 34, the exhaust filter 35, the second flat plate member 112, and the fourth flat plate member 114 described above are attached to the frame body 36 via a bracket or the like. As described above, each flat plate member arranged on the back surface side and the front surface side of the upper space S may be a member constituting the plenum unit 30. In that case, these flat plate members are attached to the frame body 36.

The bell mouth 32 has a circular bell mouth opening H3 having a radius R at the upper end thereof. Since the bell mouth 32 covers the suction port of the blower 31, the bell mouth opening H3 substantially functions as the suction port of the blower 31. That is, the bell mouth opening H3 can be regarded as a suction port of the blower 31. The bell mouth 32 has a circular frame portion 321 that surrounds the bell mouth opening H3.

The inside of the box body 33 and the exhaust filter 35 communicate with each other via the exhaust duct 37 and the exhaust box body 38. The exhaust duct 37, the exhaust box body 38, and the exhaust filter 35 constitute an exhaust portion. Incidentally, the exhaust box 38 distributes the gas (including aerosol and the like) that has passed through the exhaust duct 37 in the horizontal direction in order to allow the gas (including aerosol and the like) to enter the exhaust filter 35 from the entire lower surface of the exhaust filter 35. It is a member for making it. In addition to these members, the members constituting the exhaust unit naturally include connecting members and the like that connect these members.

In the upper part of the bell mouth 32 (that is, the blower 31), the top plate 39 is attached to the frame body 36. The top plate 39 constitutes at least a part of the ceiling of the upper space S.

An electric device storage box 40 for storing an electric device such as a fuse is attached to the frame body 36. The electrical equipment storage box 40 has a substantially rectangular parallelepiped outer shape.

A shielding plate 50 is installed in the upper space S. Specifically, the shielding plate 50 is attached below the electrical equipment storage box 40. The shielding plate 50 may be directly attached to the frame body 36.

The shielding plate 50 is installed at a position overlapping a part of the bell mouth opening H3 (that is, the suction port of the blower 31) in a plan view. In addition, "all" is not included in "part" here. Further, the shielding plate 50 is installed horizontally.

The shielding plate 50 is a flat plate having a shape (substantially C-shaped) in which a part of a large rectangle is cut out by a small rectangle in a plan view. That is, the shielding plate 50 is provided with a rectangular notch. The electrical equipment storage box 40 is housed in the notch formed by the small rectangle. Further, the lower surface of the shielding plate 50 and the lower surface of the electric device storage box 40 are substantially flush with each other.

The shielding plate 50 has a first side 51 on the back side, a second side 52 on the front side, a third side 53 on the right side, and a fourth side 54 on the left side. The first side 51 faces the first flat plate member 111. The second side 52 faces the third flat plate member 113. The third side 53 faces the second flat plate member 112. The fourth side 54 faces the fourth flat plate member 114 via an exhaust portion, specifically, an exhaust filter 35. The shielding plate 50 may be attached to the electrical equipment storage box 40 or the frame body 36 so that the fourth side 54 faces the fourth flat plate member 114 via the exhaust duct 37. By arranging the shielding plate 50 in this way, each device constituting the plenum unit 30 and the shielding plate 50 can be compactly arranged directly above the work area A, and noise as will be described later. A reduction effect can be obtained.

The cabinet 1 configured as described above operates as follows. When the operation switch of the blower 31 provided on the control panel 14 is pressed, the blower 31 starts operation.

Then, as shown by an arrow in FIG. 2, the gas in the work area A is sucked into the lower duct D1 or the back duct D2 through the front gas suction port H1 or the back gas suction port H2. .. These gases flow through these ducts and reach the upper space S, as indicated by the arrows in FIG.

The gas that has reached the upper space S is sucked into the blower 31 through the bell mouth opening H3. The gas sucked by the blower 31 is discharged into the box body 33 from the discharge port of the blower 31 as shown by an arrow in FIG.

As shown by an arrow in FIG. 2, a part of the gas discharged into the box body 33 passes through the air supply filter 34 to become clean gas, and then passes through the straightening vane 15 to work. It is supplied in area A.

The other part of the gas discharged into the box 33 passes through the exhaust duct 37 and the exhaust filter 35 to become clean gas, and then is discharged to the outside as shown by an arrow in FIG. Will be done.

When the blower 31 operates as described above and the gas flows, noise is generated from the cabinet 1. However, in the cabinet 1 according to the present embodiment, the shielding plate 50 is installed in the upper space S. In this case, surprisingly, the noise is reduced as compared with the case where the shielding plate 50 is not installed.

In order to clarify the reason why the noise is reduced by installing the shielding plate 50 in the upper space S, the experiment 1 described below was performed.

(Experiment 1)
In Experiment 1, the following test plate was used as a member corresponding to the shielding plate 50. The test plate used in Experiment 1 has a shape similar to that of the shielding plate 50, and is a flat plate having a distance of 455 mm between the side corresponding to the third side 53 and the side corresponding to the fourth side 54. A gap is formed between each side corresponding to the first side 51, the second side 52, and the third side 53 and the first flat plate member 111, the third flat plate member 113, and the second flat plate member 112. , The shielding plate 50 is installed horizontally. In the cabinet 1 used in Experiment 1, the distance between the upper end of the upper space S (lower surface of the top plate 39) and the frame portion 321 of the bell mouth 32 (upper end of the bell mouth opening H3) is 228.2 mm. Further, the distance between the common central axis O of the blower 31 and the bell mouth opening H3 and the second flat plate member 112 is 378.8 mm.

In Experiment 1, noise and total air volume were measured when the test plate was not installed (control) and when the test plate was installed at various heights. Table 1 shows the measurement conditions and measurement results. The noise level was measured according to the method specified in JIS K3800: 2009.

As shown in Table 1, the distance between the test plate and the frame portion 321 (upper end of the bell mouth opening H3) is 57.0% (228.2 mm) of the distance between the upper end of the upper space S and the frame portion 321 (228.2 mm). When it was less than 130 mm), a noise reduction effect was obtained. Further, when the distance between the test plate and the frame portion 321 is 30.7% (70 mm) or more and 44.4% (101.4 mm) or less of the distance between the upper end of the upper space S and the frame portion 321, noise is reduced. Further effects were obtained. In particular, the distance between the test plate and the frame portion 321 (upper end of the bell mouth opening H3) is 44.4% (101.4 mm) of the distance (228.2 mm) between the upper end of the upper space S and the frame portion 321. In this case, it was reduced by 1.1 (= 66.8-65.7) dB as compared with the case without the test plate. The decrease in noise of 1.1 dB is a decrease of 11.9% in terms of sound pressure. This is a fairly large decrease, not a small value.

Further, the distance between the test plate and the frame portion 321 (the upper end of the bell mouth opening H3) is 44.4% (101.4 mm) of the distance (228.2 mm) between the upper end of the upper space S and the frame portion 321. If so, the total air volume increased. This means that the blower 31 and thus the cabinet 1 can be operated with lower power consumption by properly installing the test plate shielding plate.

On the other hand, when the distance between the test plate and the frame portion 321 (the upper end of the bell mouth opening H3) is 57.0% (130 mm) of the distance (228.2 mm) between the upper end of the upper space S and the frame portion 321. The noise level did not decrease.

From the results of Experiment 1, it is presumed that the noise level may be reduced for the following reasons.

The test plate, that is, the shielding plate 50 reduces the pressure loss (resistance) on the suction side of the blower 31, thereby improving the efficiency of the blower 31 (increasing the total air volume) and reducing the noise generated from the blower 31 itself. It is speculated that it may be.

Further, in the upper space S, various members that act as resistance to the flow of gas are arranged. Therefore, the inside of the upper space S is an environment in which it is difficult for gas to flow smoothly. When a test plate, that is, a shielding plate 50 is installed in such an upper space S, as shown by arrows in FIGS. 4 and 5, at least a part of the gas flow path length is shortened and the gas flow is adjusted. It is speculated that it may be done. As a result, it is caused by the noise caused by the turbulent flow generated when the gas flows in the upper space S, the noise generated when the gas collides with the member installed in the upper space S, or the vibration of this member. It is presumed that the noise and the like will be reduced.

However, if the test plate, that is, the shield plate 50 is farther than the suction port of the blower 31 to some extent or more, it is presumed that the gas flow will be the same as when the test plate, that is, the shield plate 50 is not provided, and the noise reduction effect will be lost. Ru.

Further, when the test plate, that is, the shielding plate 50 becomes closer to the suction port of the blower 31 to some extent or more, on the contrary, the test plate, that is, the shielding plate 50 may become a resistance of the gas flow and the pressure loss on the suction side may increase. .. As a result, it is presumed that the efficiency of the blower 31 deteriorates and the noise generated from the blower 31 itself increases. As a result, it is presumed that the noise value that is reduced by adjusting the gas flow and the noise value that is increased due to the deterioration of the efficiency of the blower 31 are offset, and the noise is reduced, but the effect is slightly reduced.

(Experiment 2)
Subsequently, in order to investigate whether or not the noise changes when the degree of overlap between the shielding plate 50 and the suction port of the blower 31 in a plan view changes, the experiment 2 described below was performed.

In Experiment 2, the same cabinet 1 as in Experiment 1 was used. In Experiment 2, as the member corresponding to the shielding plate 50, four types of test plates having different distances between the side corresponding to the third side 53 and the side corresponding to the fourth side 54 were used. That is, when installed so as to form a slight gap between the second flat plate member 112, four types of test plates having different distances between the blower 31 and the common central axis O of the bell mouth opening H3 are used. board. Each test plate was horizontally installed in the upper space S. In each case, the distance between the test plate and the frame portion 321 of the bell mouth 32 was 101.4 mm.

Noise was measured using these cabinets 1 and test plates. Table 2 shows the measurement conditions and measurement results. The side-to-side distance (mm) in Table 2 is the distance between the two sides of the test plate corresponding to the third side 53 and the fourth side 54 of the shielding plate 50. The overlap rate (%) in Table 2 is the area of the portion where the suction port of the blower 31 and the test plate overlap with respect to the area of the suction port of the blower 31 (that is, the bell mouth opening H3) in a plan view. The ratio. The noise level was measured according to the method specified in JIS K3800: 2009.

As is clear from Table 2, the noise level was reduced when any of the test plates was installed as compared with the case where the test plate was not installed (control). From Experiment 2, it can be reasonably inferred that if the overlap rate is at least 2%, the noise level is reduced by a substantially constant amount regardless of the amount of increase in the overlap rate. Further, it can be reasonably inferred that even if the overlap rate is 0%, that is, as long as the test plate is present, the same noise level reduction effect as in the case where the overlap rate is 2 to 21% can be obtained. Further, as long as the pressure loss (resistance) on the suction side of the blower 31 can be reduced, even if the overlap rate is 100%, the same noise level reduction effect as when the overlap rate is 2 to 21% can be obtained. Can be reasonably inferred.

The shape and installation mode of the shielding plate 50 are not limited to those described so far. For example, the shielding plate 50 may be installed so as not to be horizontal as long as the gas flow can be adjusted, and the shape may be a plate having a curved surface instead of a flat plate. For example, it may be a plate having a curved surface that draws a convex arc upward from above the back side duct D2 toward the upper side of the bell mouth opening H3. Further, it may be a plan view, a simple rectangle or a square, instead of a shape in which a part of a large rectangle is cut out by a small rectangle. Further, the surface may have a single or a plurality of irregularities.

Further, a flat plate portion that stands vertically may be provided on a part of the shielding plate 50. For example, it may have a vertical flat plate portion that extends continuously upward in the vertical direction from the fourth side 54. In this case, the vertical flat plate portion may or may not reach the upper end of the upper space S. When the shielding plate 50 has such a flat plate portion, it is possible to more reliably prevent gas from wrapping around on the upper side of the shielding plate 50. Therefore, when the shape of the device or member installed on the upper part of the shielding plate 50 is relatively complicated, it can be expected that the noise caused by the gas flow is reduced more reliably.

Further, a flat plate portion that hangs vertically may be provided on a part of the shielding plate 50. In this case, by providing the flat plate portion in the direction perpendicular to the first flat plate member 111, it can be expected that this flat plate portion functions as a rectifying member and the noise caused by the gas flow is reduced more reliably. In particular, by providing a plurality of flat plate portions in parallel with each other, it can be expected that noise caused by the flow of gas will be reduced more reliably.

Further, the installation position of the shielding plate 50 may be a position where the lower surface of the shielding plate 50 is not substantially flush with the lower surface of the electric device storage box 40 as long as it is not too far from the frame portion 321 of the bell mouth 32. For example, the shielding plate 50 may be installed so that the lower surface of the shielding plate 50 is located above the lower surface of the electrical equipment storage box 40. Of course, the shielding plate 50 may be installed so that the lower surface of the shielding plate 50 is located below the lower surface of the electrical equipment storage box 40.

The present invention is suitably used as a biohazard countermeasure cabinet.

1 Cabinet 10 Cabinet body 11 Housing 111 1st flat plate member 112 2nd flat plate member 113 3rd flat plate member 114 4th flat plate member 115 5th flat plate member 12 Shutter 13 Lighting 14 Control panel 15 Straightening plate 20 base 30 Plenum unit 31 Blower 32 Bellmouth 321 Frame 33 Box 34 Air supply filter 35 Exhaust filter 36 Frame 37 Exhaust duct 38 Exhaust box 39 Top plate 40 Electrical equipment storage box 50 Shielding plate 51 1st side 52 2nd side 53 3rd side 54 4th side A Work area D1 Lower duct D2 Back side duct H1 Front side gas suction port H2 Back side gas suction port H3 Bellmouth opening S Upper space R Bellmouth opening radius O Center of blower and bellmouth opening shaft

Claims (8)

It is a biohazard countermeasure cabinet with a work area inside.
A blower having a bell mouth installed in an upper space arranged vertically above the work area and having a frame portion surrounding a suction port facing vertically upward.
A shielding plate fixedly installed in the upper space and above the blower,
A biohazard countermeasure cabinet equipped with. The shielding plate has a horizontal flat plate portion.
The biohazard countermeasure cabinet according to claim 1. The shielding plate has a first side and a second side parallel to each other in a plan view, and a third side and a fourth side parallel to each other in a plan view and perpendicular to the first side in a plan view.
The biohazard countermeasure cabinet according to claim 1 or 2. A first flat plate member, a second flat plate member, a third flat plate member, and a fourth flat plate member that are arranged in order clockwise in a plan view and surround the front, back, left, and right of the upper space.
Further provided with an exhaust unit installed in the upper space and guiding a part of the gas discharged from the blower.
The first side faces the first flat plate member and faces the first flat plate member.
The second side faces the third flat plate member, and the second side faces the third flat plate member.
The third side faces the second flat plate member and faces the second flat plate member.
The fourth side faces the fourth flat plate member via the exhaust portion.
The biohazard countermeasure cabinet according to claim 3. The exhaust unit has at least one of an exhaust filter, an exhaust box body, and an exhaust duct.
The fourth side faces the fourth flat plate member via the exhaust filter, the exhaust box body, or the exhaust duct.
The biohazard countermeasure cabinet according to claim 4. The shielding plate overlaps a part of the suction port in a plan view.
The biohazard countermeasure cabinet according to any one of claims 1 to 5. The area of the region where a part of the suction port and the shielding plate overlap in the plan view is 2% or more of the area of the suction port in the plan view.
The biohazard countermeasure cabinet according to claim 6. The distance between the shielding plate and the frame portion is less than 57.0% of the distance between the upper end of the upper space and the frame portion.
The biohazard countermeasure cabinet according to any one of claims 1 to 7.

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