WO2014054315A1

WO2014054315A1 - Safety cabinet

Info

Publication number: WO2014054315A1
Application number: PCT/JP2013/066465
Authority: WO
Inventors: 金子　健; 小野　恵一
Original assignee: 株式会社日立産機システム
Priority date: 2012-10-04
Filing date: 2013-06-14
Publication date: 2014-04-10
Also published as: IN2014DN11130A; MY174864A; JP5873413B2; SG11201500074XA; JP2014073457A

Abstract

Provided is a safety cabinet configured so that an inflowing air flow is not affected by the position and size of a device mounted in a work space and by the operation of equipment, such as the operation of opening and closing the lid of a centrifugal separator. A safety cabinet is provided with a work space in which a worker works, a front face shutter which is formed at the front face of the work space, a work opening section which is located below the front face shutter and which is interconnected with the work space, and an air discharge means which sucks air from the work opening section and discharges the air within the work space by means of a blower to the outside of the safety cabinet through an air purification means. The safety cabinet is characterized in that a front face shutter flow regulation plate which is tilted toward the inside of the work space is formed on the underside of the front face shutter, that the safety cabinet is provided with left and right side wall surfaces within the work surface, that side air discharge passages are formed by the side wall surfaces and by the side surfaces of the safety cabinet, that slits are formed in the left and right side wall surfaces, and that air within the work space is sent to the side air discharge passages through the slits and discharged through the air purification means.

Description

Safety cabinet

The present invention relates to a safety cabinet, and more particularly, to a safety cabinet in which devices such as a centrifuge, an analyzer, and an observation device can be incorporated in the safety cabinet for infectious disease research and pharmaceutical development.

The safety cabinet forms an air barrier by sucking air outside the safety cabinet from the work opening under the front and lower slide type front shutter formed on the front of the work space, forming an air barrier, and the atmosphere outside the safety cabinet work space and the safety cabinet Is physically shut off. The air sucked from the work opening passes through the inside of the safety cabinet, and removes infectious substances together with dust by an exhaust HEPA filter installed in the safety cabinet, and is exhausted out of the safety cabinet as clean air. The air blowing means for guiding air from the work opening to the exhaust HEPA filter may be provided inside the safety cabinet device or may be installed outside the safety cabinet device.

In the case of class I cabinets for biohazard measures classified according to the structure of the safety cabinet, the air outside the safety cabinet is directly taken into the work space of the safety cabinet, and there is no air supply HEPA filter at the top of the work space. Used when working with infectious substances in the work space, etc., for work that should ensure the safety of the worker and that do not require aseptic operation. With the above configuration, the biohazard class I cabinet is configured so that infectious substances handled in the work space do not leak out of the safety cabinet by the air barrier at the work opening and the exhaust HEPA filter.

One of the tasks to handle the device in the work space of the safety cabinet is to open the centrifuge lid. In the centrifuge, since the infectious experimental material is rotationally agitated, a large amount of droplets (aerosol) is generated inside. Furthermore, at the instant when the lid of the centrifuge is opened, internal droplets (aerosol) are discharged outside the centrifuge. In this way, infectious droplets (aerosols) may be released, preventing the spread of infectious substances to the outside by opening the centrifuge lid in the work space of the safety cabinet. .

A structure in which a conventional centrifugal separator is incorporated in a safety cabinet is shown in Patent Document 1 (Japanese Patent Laid-Open No. 2007-111596). The centrifugal separation tank of the centrifuge is arranged on the downstream side (lower surface) of the work space, and as described in the embodiment, the airflow entering from the vent hole under the shutter is below the centrifuge formed on the work table lower surface. It flows so as to surround the separation tank and is led to the return duct. With this configuration, clean air in the work space above the centrifuge is maintained, and the work space and the outside of the safety cabinet are isolated by an air barrier formed by a vent hole under the shutter. The airflow for the air barrier passes through the lower part of the centrifuge formed on the lower surface of the work space and is guided to the return duct.

JP 2007-1111596 A

A safety cabinet incorporating the above-described conventional centrifugal separator is shown in Patent Document 1 (Japanese Patent Laid-Open No. 2007-111596). In Document 1, a lid is formed on the work table surface on the lower surface of the work space, and a separation tank of a centrifuge is formed below the cover. The airflow that has come down from the work space is sucked from three places: a vent hole in the work space, a space between the work table surface and the centrifuge separation tank, and a vent hole under the shutter and led to the return duct. The airflow sucked from the vent hole under the shutter passes through the return duct below the separation tank of the centrifuge and is guided to the blower. With this configuration, the work space and the space outside the safety cabinet are physically separated by the airflow under the shutter while maintaining the cleanliness that is the clean airflow in the work space.

In a safety cabinet incorporating a centrifuge according to the prior art, the airflow sucked from the lower part of the shutter passes through the lower part of the centrifuge and is guided to the return duct. Therefore, if the centrifuge position on the work surface changes, the air is sucked from the lower part of the shutter. There is a possibility that the state of airflow will change.

Also, if you want to introduce a centrifugal separator with a large capacity or a free-standing centrifugal separator, the airflow drawn from the bottom of the shutter becomes an obstacle to the device built into the cabinet, and the air barrier is not efficiently exhausted. There is a possibility that it cannot be formed, and since the height of the shutter opening is as small as about 200 mm, the workability is very poor in the operation of opening the lid of a large centrifuge.

In the case of a safety cabinet, it is necessary to re-evaluate the physical isolation performance using Bacillus subtilis spores when the airflow state changes as described in Japanese Industrial Standards JIS K3800 Biohazard Class II Cabinet. In a class I cabinet, it is necessary to evaluate the airflow balance performance related to the safety of the operator of the above standard.

An object of the present invention is to provide a safety cabinet in which the inflow airflow is not affected by the position, size, and operation of the device incorporated in the work space, for example, the operation of opening and closing a lid such as a centrifuge. is there.

Also, in a safety cabinet that has an important function of preventing infectious materials from entering the work space, the infectious spray (aerosol) generated in the work space does not stay in the work space, and is the shortest distance. Can provide a safety cabinet that can be evacuated.

When the work opening is wide as 400 mm or more, the wind speed near the center of the opening becomes slow. To secure an air barrier, a front shutter structure with a vertical slide type is used, and the work opening is set to about 200 mm during work or It is necessary to increase the wind speed of the entire opening, which increases the exhaust air volume of the exhaust fan and increases the heat load of the building.

Another object of the present invention is to improve the wind speed distribution in the work opening, eliminate the need for a sliding front shutter, and secure an air barrier with the minimum necessary wind speed, thereby reducing power consumption and building thermal load. It is to suppress. Another object of the present invention is to provide an airflow configuration in which the basic performance of the safety cabinet is not affected even when the lid of an embedded device such as a centrifuge is opened.

In order to achieve the above object, the present invention provides a work space where an operator works, a front shutter formed on the front surface of the work space, a work opening connected to the work space below the front shutter, A front cabinet above the work opening, comprising: a safety cabinet having a suction unit for sucking air from the work opening and exhausting the air in the work space to the outside of the safety cabinet by a blower through an air cleaning unit. A front shutter rectifying plate inclined inward of the work space is formed below the front shutter, and left and right side wall surfaces in the work space are provided, and the side wall surface and the side surface of the safety cabinet are provided. A side exhaust flow path is formed, first slits or punching holes are formed in the left and right side wall surfaces, and air in the working space is passed through the slits or punching holes to the side. Feeding the exhaust passage, and wherein the evacuating via said air cleaning unit.

In the safety cabinet, the first slit or the punching hole is formed below the front shutter rectifying plate in the extension line direction.

Further, in the safety cabinet, a chamber is provided between the ceiling plate of the work space and the HEPA filter of the air cleaning means, the side exhaust flow path is connected to the chamber, and laterally extends to the back side of the ceiling plate. The second slit is formed in the above.

According to the present invention, when a device such as an analyzer or an observation device is installed in a work space of a safety cabinet, and placed or fixed, the wind speed of the suction airflow (inflow airflow) formed in the work opening and It is possible to provide a safety cabinet in which the inflow airflow is not affected by the position of the airflow, the position of the apparatus, the operation of the device, for example, the operation of opening and closing a lid such as a centrifuge.

Also, in a safety cabinet that has an important function of preventing infectious materials from staying in the work space, infectious sprays (aerosols) generated in the work space are exhausted at the shortest distance without staying in the work space. Can provide a safety cabinet that can be done.

The external appearance perspective view and longitudinal cross-sectional view of the safety cabinet carrying the class I type centrifuge which shows 1st Embodiment of this invention are shown. The front sectional drawing and side sectional drawing of the safety cabinet of this invention shown in FIG. 1 are shown. The simple model for analysis for the voxel analysis of the safety cabinet of the present invention is shown. The analysis conditions and analysis range for voxel analysis of the safety cabinet are shown. The analysis result of the flow of the air in the center sectional view shown to FIG. 3A is shown. The longitudinal cross-sectional view of the simple model for an analysis of the safety cabinet which has a front shutter rectifier of the present invention is shown. The analysis result of the flow of the air by the front shutter rectifier of FIG. 4A is shown. The cross-sectional perspective view and side view of the model for analysis which have arrange | positioned the slit formed in the left and right side wall surface of the working space of the safety cabinet of this invention in the extension line direction of a front shutter rectifier plate are shown. 5A shows an analysis result of air flow in a central vertical portion of the safety cabinet of FIG. 5A. The analysis result of the air flow of the center horizontal part of the safety cabinet of FIG. 5A is shown. The analysis result of the air flow of the front part of the safety cabinet of FIG. 5A is shown. The perspective view of the analysis model of the safety cabinet which formed the slit in the back | inner side of the ceiling board of the work space upper part of this invention is shown. The analysis result of the air flow of the safety cabinet of FIG. 6A is shown. The perspective view of the safety cabinet when mounting the centrifuge of this invention is shown. The cross-sectional perspective view of the safety cabinet which made the front shutter which shows 2nd Embodiment of this invention movable is shown. The system which detects opening and closing of the lid | cover of the centrifuge which shows 3rd Embodiment of this invention, and varies the flow volume of a fan is shown. The side view of the safety cabinet for demonstrating the area and the wind speed in the opening part of the working space which shows 4th Embodiment of this invention, and the slit of the side wall surface on either side is shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Example 1)
FIG. 1 shows an external perspective view and a longitudinal sectional view of a class I type safety cabinet equipped with a centrifuge showing Embodiment 1 of the present invention, and FIG. 2 shows a front sectional view of the safety cabinet of FIG. Side surface sectional drawing is shown. Class I type safety cabinets generally have a structure that prevents the discharge of aerosol by injecting air from the entire opening for the purpose of protecting workers, and directly injects indoor air and exhausts HEPA filters. It is the composition which discharges through. The safety cabinet of the present invention shown in FIGS. 1 and 2 is an improvement based on this class I configuration.

1 and 2, 10 is a safety cabinet, 11 is a work space where an operator works, 12 is a fixed front shutter disposed above the opening of the work space, and 13 is a tip of the fixed front shutter 12. Arranged front shutter rectifier plate, 14 HEPA filter, 15 blower, 16 exhaust duct, 17 exhaust airflow, 18 opening of work space, 19 incoming airflow from outside of safety cabinet, 20 work space The left and right walls 31 have exhaust slits, 21 is a centrifuge disposed below the work space, 22 is a lid of the

centrifuge

21, and 23 is an infectious substance. Reference numeral 24 denotes a side exhaust passage disposed on the left and right sides of the work space, 25 denotes an air flow flowing from the work space to the side exhaust passage 24 through a slit 20 (referred to as a first slit), and 26 denotes a flow in the side exhaust passage 24. Shows air flow. 27 indicates a negative pressure in the work space, 28 indicates a slit (referred to as a second slit) disposed on the back side of the ceiling plate 41 in the work space, 29 indicates a caster, and 30 indicates the left and right sides of the work space. A chamber (referred to as a first chamber) in which air exhausted from the slit 20 on the wall surface and the slit 28 on the back side of the ceiling plate 41 gathers, 31 is the left and right side wall surfaces of the work space, 32 is the air after passing through the HEPA filter 14 A chamber for exhausting air from the blower 15 (referred to as a second chamber), 33 is an upper front part of the cabinet body, 50 is a lower front part of the cabinet body, and 51 is a side part of the cabinet body.

Next, the configuration of the safety cabinet of the present invention will be described. 1 and 2, a fixed front shutter 12 is disposed above the opening 18 of the work space 11, and a front shutter rectifying plate 13 is inclined to the inside of the work space at the lower end of the fixed front shutter 12. Formed and arranged. When this front shutter rectifying plate 13 is not formed and only the fixed front shutter 12 is provided, the air inflow air 19 into the work space is along the entire peripheral side wall of the lower surface of the fixed front shutter 12 and the opening 18 of the work space. Therefore, there is a possibility that a wind speed distribution can be achieved in which the wind speed increases and the wind speed near the center of the work space 18 decreases. In order to eliminate this imbalance in the wind speed distribution, a front shutter rectifying plate 13 is disposed. This effect will be described later.

A ceiling plate 41 is formed on the upper side of the work space 11, and a space is formed on the upper portion of the ceiling plate 41 by a ceiling surface and a surface on which the HEPA filter 14 is disposed, and a chamber for collecting air exhausted from the work space 11 30 is formed. The air in the chamber 30 is sucked into the HEPA filter 14 and filters dust, infectious substances 23, and the like. The clean air that has passed through the HEPA filter 14 is exhausted to the outside of the safety cabinet 10 by the blower 15 via the exhaust duct 16. A chamber 32 of clean air space in which the blower 15 is installed is formed.

Further, a space is formed by the left and right side wall surfaces 31 of the work space 11 and the side surface portion 51 of the safety cabinet 10, and the air in the work space 11 is caused to flow into this space to form the side exhaust flow path 24. Upper portions of the side exhaust passages 24 formed on the left and right sides of the work space are connected to the first chamber 30. Further, the air in the work space 11 flows through the slits formed in the left and right wall surfaces of the work space and flows into the side exhaust flow path 24. In FIG. 1 and FIG. 2, the vertically elongated slit holes are formed in the vertical direction on the left and right side wall surfaces of the work space, but they may be punched holes or elliptical holes. Further, a plurality of second slits 28 that are elongated in the width direction are arranged at the back of the ceiling plate 41 so that the air on the back side in the work space flows upward.

The front shutter rectifying plate 13 disposed below the fixed front shutter 12 is provided to improve the wind speed distribution of the working opening 18 and has a length of 50 to 150 mm and a fixed angle of fixed. From the front shutter 12 toward the work space 11, it is fixed at an angle of 30 to 60 ° from the horizontal. The material may be a transparent glass surrounded by a SUS frame or a steel plate. Further, along the extension line of the front shutter rectifying plate 4, left and right side slits 20 for exhaust provided in the work space 11 are directed from the front to the back of the work space 11 in order to rectify the inflow air flowing from outside the cabinet. Thus, the opening area is gradually reduced.

Also, a centrifuge 21 is mounted in the lower part of the work space of the safety cabinet 10. As shown in FIG. 7, the centrifuge 21 is mounted by removing the lower front plate 50 of the safety cabinet 10 and moving the centrifuge 21 with the casters 50 to the lower part of the work space. Moreover, when the lid 22 of the centrifuge is opened so that the operator can work easily, the centrifuge is installed so as to fall down on the back side of the work space. After installation, the lower front plate 50 of the safety cabinet is attached. Further, the lower front plate 50 of the cabinet 10 may be fixed by screwing on both sides or may be provided with a hinge on one side and fixed as a door. Casters 29 are provided on the legs of the safety cabinet so that they can be moved with a light force when moving.

Next, the result of the voxel analysis of the air flow in the configuration of the safety cabinet of the present invention will be described. First, in FIG. 3A to FIG. 3C, the front shutter rectifying plate 13 is not formed, the slits 20 formed on the left and right wall surfaces 31 of the work space are arranged in three rows in the vertical direction, and the shape is an elongated vertically long hole, and the slit is arranged. This area is set at the approximate center of the wall, and the air flow is analyzed when the entire area is formed in a rectangular area.

FIG. 3A shows a perspective view and a longitudinal sectional view of a simple model for analysis of a safety cabinet to be analyzed. In the simplified model for analysis of the safety cabinet shown in FIG. 3A, the width (L2) of the cabinet is 850 mm, the height (L1) is 1950 mm, the depth (L3) is 780 mm, the width (L6) of the opening in the work space is 650 mm, the work The height (L5) of the opening of the space is 550 mm. The average wind speed is 0.5 m / s. The slit 20 has a configuration in which 60 holes of 100 mm × 10 mm are formed on one side.

Moreover, the conditions for analyzing the simple model for analysis shown in FIG. 3A are shown in FIG. 3B. FIG. 3B shows the conditions to be analyzed, FIG. 3B (a) shows the input unit representing the setting of the cross-sectional calculation, and FIG. 3B (b) shows the range to be analyzed. In FIG. 3B (a), when the height direction of the simplified model for analysis of the safety cabinet is the y direction, the width direction is the x direction, and the depth direction is the z direction, the number of cross sections is 300 in the y direction, the z direction is 175, When analysis is performed by dividing the x direction into 175, the voxel size display is about 9.2 million cells, and the analysis range is a range including the entire cabinet as shown in FIG. 3B (b).

The result of analysis under the above analysis conditions is shown in FIG. 3C. FIG. 3C shows the air flow in the longitudinal section of the safety cabinet shown in FIG. 3A (b). In FIG. 3C, 100 indicates the air flow below the opening of the work space, 120 indicates the air flow in the chamber 30 above the

ceiling plate

41, and 130 indicates the air flow in the exhaust chamber 32. The region from 100 to 130 is a portion where the wind speed is high, and in the figure, the wind speed is indicated by an arrow line, and the black bundle portion indicates that the wind speed is high. In this figure, the air flow is about 1 m / s with respect to the average wind speed of 0.5 m / s. Also, in the work space, the air that has flowed in as shown by the arrows flows in from the opening and flows toward the back, and since there is no front shutter rectifying plate, it is caught at the upper end of the opening of the work space. Turbulent flow is generated, and the air is exhausted from the slits 20 on the left and right side wall surfaces.

Next, the flow of air when the front shutter rectifying plate 13 is arranged will be analyzed. FIG. 4A shows a configuration in which a front shutter rectifying plate 13 is inclined at the front end of the fixed front shutter 12 and inclined toward the work space. The slits 20 formed on the left and right side walls in the work space are the same as in FIG. 3A, and 60 holes of 100 mm × 10 mm (both sides) are formed. The air flow in the configuration of FIG. 4A is shown in FIG. 4B. In FIG. 4B, the part where the wind speed is high is a part surrounded by a circle (dotted line), 140 indicates the air flow below the opening of the work space, and 150 indicates the air flow above the opening of the work space. Reference numeral 160 denotes an air flow in the chamber 30 above the ceiling plate, and 170 denotes an air flow in the exhaust chamber 32.

Also, in the work space, the air that flows in along the front shutter rectifying plate 13 out of the air that flows in from the opening is caught in the upper side of the work space and generates turbulent flow. That is, when the arrangement of the slits 20 on the left and right side walls is the same, and the front shutter rectifying plate 13 is arranged, the formation of the slits 20 is the same as the configuration of FIG. To do.

Next, the front shutter rectifying plate 13 is arranged, the slit 20 is arranged, and the flow of air when the arrangement of the slit 20 is changed is analyzed. In FIG. 5A, the front shutter rectifying plate 13 is disposed at the front end of the fixed front shutter 12 so as to be inclined toward the working space, and the arrangement of the slits 20 formed on the left and right side wall surfaces of the working space is an extension of the front shutter rectifying plate 13. The structure arrange | positioned below the direction is shown, and the flow of the air of this structure is analyzed.

5A shows a cross-sectional perspective view of a simplified analysis model of a safety cabinet in which the front shutter rectifying plate 13 is formed in the upper part of the opening and the slit 20 is disposed below the extending direction 40 of the front shutter rectifying plate 13. (B) shows a side view. As shown in FIG. 5A (b), the slits 20 are arranged in three rows below the extension line 40 of the front shutter rectifying plate 13, and the range of the arrangement is substantially triangular.

FIG. 5B shows the analysis result of the air flow having the configuration shown in FIG. 5A (a). In FIG. 5B, the part where the wind speed is high is a portion surrounded by a circle (dotted line), 180 indicates the air flow below the opening of the work space, and 190 indicates the air flow above the opening of the work space. 200 indicates the air flow in the chamber 30 above the

ceiling plate

41, and 210 indicates the air flow in the exhaust chamber 32. Further, in this configuration, when the flow of air in the work space is viewed, the air that flows in along the front shutter rectifying plate 13 out of the air that flows in from the opening portion is hardly entangled upward, and the front shutter rectification is performed. It concentrates in the slit 20 arrange | positioned on the lower side of the extension line direction of the board 13, and is exhausted. 4B, the overall arrangement of the slit 20 in FIG. 5B is arranged below the extension line of the rectifying plate 13, and the substantially triangular air flow is compared with the flow of air when the entire arrangement of the slit 20 in FIG. 4B is rectangular. In the case of the flow, the wind speed in the slit 20 is higher.

In this manner, the front shutter rectifying plate 13 is disposed on the upper side of the opening so as to be inclined inward of the work space, and the range of the slit 20 disposed on the left and right side walls of the work space is below the extension line direction of the rectifying plate 13. With the configuration in which the entire arrangement of the slits 20 is substantially triangular, the aerosol can be prevented from being released from the opening when the centrifuge lid is opened.

Next, FIG. 5C shows the analysis result of the horizontal air flow in the central portion of the work space in the simplified analysis model of the safety cabinet shown in FIG. 5A. In FIG. 5C, a large amount of air with high wind speed passes through the slit 20 from the work space and flows in the side exhaust passage 24, and the wind speed at the center is low and the wind speed on both sides is high in the work space. In addition, the wind speed is low on the back side of the work space, and there is a possibility that it may be hazy.

Next, FIG. 5D shows the analysis result of the air flow in the front central section of the working space and the exhaust part in the simplified model for analysis of the safety cabinet shown in FIG. 5A. In FIG. 5D, the air flow in the vicinity of the center from the opening of the work space has a low wind speed at the center of the work space, the wind speed increases as it approaches the left and right side walls, and the portion where the slit 20 is located is higher. That is, although the slits 20 are arranged in three rows in the vertical direction, it can be seen that the wind speed at that portion is high. Further, in the side exhaust passage 24 and the chamber 30 on the ceiling plate, the wind speed is high, and the wind speed of the exhaust duct portion of the exhaust chamber 32 is high. Also, the wind speed at the upper center of the work space is low.

Next, the flow of air when the slit 28 is arranged on the back side of the ceiling plate 41 arranged at the upper part of the work space will be analyzed, and the analysis result will be described. FIG. 6A shows a longitudinal sectional perspective view and a plan view of the ceiling board 41 of a simple model for analysis of a safety cabinet in which slits 28 are arranged. In this simple model for analysis, the front shutter rectifying plate 13 is arranged above the opening of the work space, the slit 20 is arranged below the extending line direction of the rectifying plate 13, and below the extending line direction of the rectifying plate 13. A plurality of slits 20 are vertically arranged on the side, the entire range of the slits is substantially triangular, and the slits 28 are arranged in the width direction on the back side of the ceiling surface 41. Further, in this configuration, the circle A is a place where air easily stagnates.

FIG. 6B shows the analysis result of the air flow in the configuration of FIG. 6A. In FIG. 6B, the air that has flowed in through the opening of the work space travels straight and flows through the slits 20 on the left and right side wall surfaces 31, and the air that flows in along the rectifying plate 13 flows on the slits on the left and right side wall surfaces. It can be seen that there are those heading toward the direction 20 and those heading toward the slit 28 on the back side of the ceiling plate of the work space. And although air was easy to stagnate above the back side of the work space, the stagnation is eliminated by the slit 28 arranged on the back side of the ceiling board.

(Example 2)
Next, it forms so that the front shutter 80 which has arrange | positioned the front shutter rectification | straightening plate 13 of Example 2 of this invention to the front-end | tip can be slid up and down, and an operator sets the height of the opening part of a safety cabinet according to the work content. A configuration that can be adjusted is shown in FIG. In FIG. 8, the front shutter 80 is formed so as to be sandwiched between the upper front portion 33 and the upper front portion back plate 42 of the safety cabinet and is configured to be slidable. Further, when the worker works, the front shutter rectifying plate 13 can be made detachable so that it can be removed if it hinders the work. The front shutter 80 is transparent so that the work space can be seen. In the case of Example 1, since it is a fixed type, it may be opaque. In addition, a handle is formed in the center of the outer side of the front shutter 80 so that the operator can perform an up / down sliding operation.

(Example 3)
Next, when the lid 22 of the centrifuge 21 according to the third embodiment of the present invention is opened, the rotational speed of the exhaust fan 15 is increased, and the aerosol in the centrifuge 21 is not discharged from the opening of the working space. This will be described with reference to FIG. In FIG. 9, 21 is a centrifuge, 22 is a centrifuge lid, 60 is a sensor for detecting the opening / closing of the centrifuge lid 22, 61 is a lid opening / closing sensor input circuit, and 62 is a detection for detecting the opening / closing of the lid. A circuit, 63 is a controller for controlling the motor, 64 is a motor for driving the

blower

15, and 15 is a blower.

Next, the operation of FIG. 9 will be described. First, the operator puts the sample between the centrifuges, inserts the centrifuge between the rotors, opens the lid of the centrifuge, puts the rotor in the chamber of the separator, closes the lid, and turns on the SW of the centrifuge To do. When the operation is complete, open the centrifuge lid, remove the rotor and close the lid. An open / close sensor 60 arranged at the lid is installed, and when the lid of the centrifuge is opened, a lid open signal is sent to the lid open / close sensor input circuit 61, and the detection circuit 62 detects that the lid has been opened. To do. When it is detected that the centrifuge lid is opened, the motor controller 63 temporarily increases the rotating power for a predetermined time, increases the rotational speed of the motor 64, and increases the wind force of the blower 15.

With this configuration, when the centrifuge lid is opened, the aerosol in the centrifuge chamber is exhausted from the work space through the slits 20 on the left and right side walls and the slit 28 on the back side of the ceiling plate 41, It is not discharged from the opening of the work space. Therefore, the safety of the worker is further improved. In addition, since the centrifuge 21 and the safety cabinet 10 are not integrated, they are connected via a connector or wirelessly transmitted to the cabinet body to connect the sensor output. In addition, as a sensor for detecting the opening / closing of the centrifuge lid, an optical sensor is used to emit light on a part of the lid surface, receive reflection from the lid surface, and detect the opening / closing of the lid. There are built-in reed switches that turn on and off at the same time, and mechanical switches such as μ switches.

Example 4
Next, the optimal area ratio and wind speed of the slit 20 of the opening surface of the safety cabinet of Example 4 of this invention and the side wall surface of the right and left of a working space are demonstrated. In the class I type safety cabinet for the centrifuge of the present invention, the optimum opening area of the entire slit 20 disposed on the left and right side walls of the work space is obtained. As a method for obtaining the size of the opening of the slit 20 on the left and right side walls, the resistance due to the speed change when exhausting from the work space and passing through the slit 20 in the in-machine resistance of the safety cabinet is set to 2 to 3 Pa depending on the characteristics of the blower 15. Determine to be. According to such resistance, it is not necessary to increase the capacity of the blower, and the exhaust can be efficiently performed. If the resistance value is too high, it is necessary to increase the performance of the blower. Conversely, if the resistance value is too low, the wind speed per one slit 20 is low, and aerosol generated in the center of the work space enters the slit 20. The attractive force is weak and exhaust cannot be performed efficiently.

Here, the in-machine resistance is a pressure loss where a speed change occurs in the flow path, and the pressure loss ΔP due to the speed change is expressed by the following equation.

ΔP = η × (1/2) × ρ × (V1 ² −V2 ² ) (Equation 1)
In (Equation 1), η is the pressure loss coefficient, ρ is the density of the fluid (1.2 for air), V1 is the speed before the speed changes, and V2 is the speed after the speed changes. Moreover, although the pressure loss coefficient η varies depending on the material in the flow path, the fluid velocity, etc., it may not be 1 or more in the case of a large size, so 1 may be used in the rough calculation.

Next, the opening of the work space and the slits 20 on the left and right side walls of the work space will be described using the steps shown in the simplified model for analysis of the safety cabinet shown in FIG. 3A (a). The area S _IN of the opening of the opening or air inlet of the working space,
S _IN = 0.65 m (width) × 0.55 m (length) = 0.36 m ² .

Further, the total area S _OUT of the slits 20 is 100 mm × 10 mm in the area of one slit, and 40 are arranged on one side.
S _OUT = 0.1 m × 0.01 mm × 40 pieces × 2 = 0.08 m ²
Therefore, in the configuration of the present invention, the ratio of the optimum opening area of the work space and the total area of the slits on the left and right side walls is S _IN / S _OUT = 0.22. Therefore, the ratio between the optimum opening area of the work space and the total area of the slits on the left and right side walls may be in the range of 0.1 to 0.3.

Next, the wind speed of the safety cabinet of the present invention will be described. First, the air volume Q in the work space is usually 0.5 m / s because the velocity of the air flowing into the opening is 0.5 m / s.
Q = 0.36 (m ² ) × 0.5 (m / s) × 60 (s)
= 10.7 (m ³ / min)
Q is 10.7 m ³ / s.
Accordingly, the wind speed V of the slits on the left and right side wall surfaces in the work space is
V = 10.7 (m ³ /min)/0.08 (m ² ) / 60 (s) = 2.23 (m / s). Therefore, the ratio of the wind speed of the slits on the left and right side wall surfaces in the work space to the wind speed of the air flowing into the opening is 4.4. Therefore, the ratio of the wind speed of the slits on the left and right side wall surfaces in the work space to the wind speed of the air flowing into the opening may be about four times as high.

With this configuration, the wind speed distribution of the work opening 18 is improved, and an air barrier can be secured even in the case of a wide opening where the height of the work opening 18 exceeds 400 mm, thereby improving workability. Further, the infectious substance 23 generated during the experiment work in a device such as a centrifuge, an analyzer, or an observer incorporated in the safety cabinet 10 is efficiently transferred from the work space 11 to the side exhaust passages 24 installed on the left and right of the work space. Discharged. Since the configuration does not exhaust from the back of the work space 11, even when a large device is mounted in the safety cabinet 10, the depth space can be minimized, the carry-in route and the installation space can be secured, and the centrifugal built into the safety cabinet 10. Even when the open / close lid 22 of the apparatus 21 such as a separator, analyzer or observer moves up and down, a stable air flow can be formed without obstructing the exhaust path so that the work can be performed with peace of mind. became.

DESCRIPTION OF SYMBOLS 10 ... Safety cabinet, 11 ... Working space, 12 ... Fixed front shutter, 13 ... Front shutter baffle plate, 14 ... HEPA filter, 15 ... Blower, 16 ... Exhaust duct, 17 ... Flow of exhaust air, 18 ... Work opening , 19 ... Inflow air from outside the cabinet, 20 ... Slits on the left and right side walls (first slit) in the work space, 21 ... Centrifuge, 22 ... Centrifuge lid, 23 ... Infectious substance, 24 ... Side Exhaust flow path, 25 ... Air flow in the side

exhaust flow path

24, 28 ... Slit (second slit) formed on the back side of the ceiling plate in the work space, 29 ... Caster, 30 ... Between the ceiling plate and the HEPA filter Chamber (first chamber), 31... Left and right side wall surfaces of work space, 32 .. Exhaust chamber (second chamber), 40. Extension line of front shutter rectifier plate, 41. Ceiling plate of work space, Side portions of 1 ‥ safety cabinet, 60 ‥ cover opening and closing sensor of the centrifuge, 62 ‥ cover opening and closing sensor sensing circuit, 63 ‥ motor controller, for 64 ‥ blower motor, 80 ‥ movable front shutter.

Claims

A workspace where workers work,
A front shutter formed in front of the work space;
A work opening connected to the work space below the front shutter;
An exhaust means for sucking air from the work opening and exhausting the air in the work space to the outside of the safety cabinet through an air cleaning means by a blower,
Fixing the front shutter above the working opening;
Forming a front shutter rectifying plate inclined inward of the work space below the front shutter;
Left and right side wall surfaces in the work space are provided, and side wall exhaust passages are formed by the side wall surfaces and the side surfaces of the safety cabinet,
Forming first slits or punching holes in the left and right side wall surfaces;
A safety cabinet characterized in that air in the working space is sent to the side exhaust passage through the slit or punching hole and exhausted through the air cleaning means.
The safety cabinet of claim 1,
The safety cabinet, wherein the first slit or the punching hole is formed on the lower side of the extended direction of the front shutter rectifying plate.
The safety cabinet according to claim 1 or 2,
A chamber is provided between the ceiling plate of the work space and the HEPA filter of the air cleaning means, and the side exhaust flow path is connected to the chamber,
A safety cabinet, wherein a second slit is formed in the lateral direction on the back side of the ceiling board.
The safety cabinet according to claims 1 to 3,
Mount the centrifuge at the bottom of the working space,
A safety cabinet characterized in that when the lid of the centrifuge is opened, the output of the blower is increased for a predetermined time.
The safety cabinet according to claim 4,
The system for opening the centrifuge lid and increasing the rotational speed of the blower is:
A lid opening and closing sensor installed on the centrifuge lid and the centrifuge body;
A detection circuit for detecting an open state of the lid by the lid open / close sensor;
A safety cabinet, comprising: a motor controller that increases the rotational speed of the blower when the detection circuit determines that the lid is open.
The safety cabinet according to claims 1 to 3,
The safety cabinet according to claim 1, wherein the ratio of the opening area of the working space to the opening area of the first slit or punching hole formed on the left and right side wall surfaces is a value of 0, 1 to 0.3.
The safety cabinet according to claim 6,
The safety cabinet characterized in that the wind speed passing through the first slits or punching holes on the left and right side wall surfaces is approximately four times the wind speed of the air flowing into the opening of the work space.
A workspace where workers work,
A front shutter formed in front of the work space;
A work opening connected to the work space below the front shutter;
A blower for sucking air from the work opening and exhausting the air in the work space to the outside of the safety cabinet via a HEPA filter;
A safety cabinet having a centrifuge installed at a lower portion of the work space,
The front shutter above the working opening is movable,
Forming a front shutter rectifying plate inclined inward of the work space below the front shutter;
Left and right side wall surfaces in the work space are provided, and side wall exhaust passages are formed by the side wall surfaces and the side surfaces of the safety cabinet,
The first slit is formed on the left and right side wall surfaces below the front shutter rectifying plate in the extension line direction, and air in the working space is exhausted from the first slit to the side exhaust passage. And
Forming a second slit laterally on the back side of the ceiling plate of the work space;
A safety cabinet characterized in that air in the work space passes through the first slit and the second slit and is exhausted through the HEPA filter.