JP2013051962A - Safety cabinet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety cabinet corresponding to the height of a worker who works in the safety cabinet, that is, the safety cabinet which allows various outside bacteria not to invade a work space even if an opening size of a front face shutter is changed, and microbes and bacteria in a working chamber not to discharge outside.SOLUTION: The opening size of the front face shutter is detected. Corresponding to the size, the blowing wind velocity of a clean air current inside the working chamber, and the inflow wind velocity of a front face opening are changed to a predetermined wind velocity able to maintain a physical isolation capability to prevent any infection.

Description

The present invention relates to a clean workbench for preventing disasters caused by handling of microorganisms and pathogens in research on pathogens such as genetic manipulation in medicine and pharmaceuticals, research on infectious diseases, etc., and a so-called safety cabinet for biohazard countermeasures.

Conventionally, when handling microorganisms / pathogens, safety cabinets have been used as primary barriers that physically isolate the microorganisms / pathogens to be handled from people and the environment. In order to maintain the isolation performance of the safety cabinet, it is important to maintain the blowing air speed of clean air supplied to the work space and the inflow air speed of the air barrier sucked from the front opening. A conventional safety cabinet is shown in Patent Document 1 (Japanese Patent Laid-Open No. 62-132550). Since the safety cabinet according to the prior art keeps the inflow air velocity sucked from the front opening constant, the opening dimension of the front opening is used at a fixed position. In the prior art, when using a safety cabinet,
Even if the HEPA filter, which is a cleaning means, is clogged and its pressure loss resistance changes, the wind speed necessary to maintain performance is detected by the wind speed sensor, and the blower (blower) is controlled so that the wind speed falls within the set value. doing.

JP-A-62-132550

As shown in Japanese Industrial Standard JIS K3800: 2000, the safety cabinet of the prior art contains microorganisms and pathogens in the work space, protects the internal microorganisms and pathogens from external germs, and also protects the microorganisms and pathogens in the work space. Maintain the performance of physically isolating the inside and outside of the work space by maintaining the air speed of clean air blown into the work space and the inflow air speed sucked from the front opening at a constant value. ing. In the safety cabinet according to the prior art, in order to keep the inflow air velocity at the front opening constant, the front opening is fixed to a constant opening such as 200 mm. The user inserts an arm into the work space from the front opening to handle microorganisms and pathogens. Also, through the front shutter at the top of the front opening,
It looks like it looks into the work space.

The safety cabinet according to the prior art has a problem that the operating range of the hand inserted into the work space is limited because the front opening size when handling microorganisms / pathogens is a fixed size. In addition, the size of the front opening for inserting a hand into the work space is wider than the usual 200 mm, 250
In the case of a safety cabinet such as mm to 300 mm, there is a drawback that a person with a short height is difficult to work.

The objective of this invention is providing the safety cabinet excellent in the usability corresponding to the height of an operator.

In order to achieve the above object, the present invention provides an air supply system for supplying clean air to the work space through the first air cleaning means by the blowing means, a front shutter formed on the front surface of the work space, and a work under the front shutter. A front opening connected to the space, an exhaust system for sucking air from the front opening and discharging the air out of the apparatus through the second air cleaning means, and first and second air cleaning means and air blowing means In the safety cabinet having the pressure chambers connected to each other, the blowing air speed supplied to the work space and the suction air speed sucked from the front opening are controlled according to the opening size of the front opening.

In the safety cabinet, the blowout wind speed supplied to the work space and the inflow wind speed sucked from the front opening are individually controlled according to the opening size of the front opening.

Further, in the safety cabinet, the position of the front opening from the floor can be changed according to the height of the worker.

The present invention provides a user-friendly safety cabinet that can be used by users of all heights at the front opening size of a safety cabinet that is easy to use.

It is a perspective view which shows the safety cabinet which shows 1st Embodiment of this invention. It is a section construction figure showing the safety cabinet which shows a 1st embodiment of the present invention. It is a perspective view of the front-surface opening dimension detection means which shows 1st Embodiment of this invention. It is sectional structure drawing which shows the safety cabinet which shows 2nd Embodiment of this invention. It is sectional structure drawing which shows the safety cabinet which shows 3rd Embodiment of this invention. It is sectional drawing which shows the safety cabinet which shows 4th Embodiment of this invention. It is a perspective view which shows the safety cabinet which shows 5th Embodiment of this invention. It is a figure which shows the relationship between the height of the worker of this invention, and a safety cabinet.

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

FIG. 1 is a structural diagram showing a safety cabinet showing a first embodiment of the present invention.
The operator inserts his / her arm through the front opening 10 of the safety cabinet 1, looks into the work space 3 from the front shutter 9, and performs work that handles bacteria and viruses in the work space 3.

  FIG. 2 is a cross-sectional structure diagram showing the safety cabinet showing the first embodiment of the present invention.

The air that has passed through the HEPA filter 5 is sent into the work space 3 of the safety cabinet 1 through the current plate 20 into the work space 3.

The air 13 sucked from the front opening 10 passes through the circulation passage 7 at the lower part of the work table 2 and the work space 3 and is sucked into the blower 6. The air sucked into the blower 6 is pressurized in the pressure chamber 18. An exhaust HEPA filter 4 and an air supply HEPA filter 5 are connected to the pressure chamber 18, and the air sucked from the front opening 10 is filtered with bacteria / viruses 15 by the exhaust HEPA filter 4 to obtain clean air. The air is exhausted from the exhaust port 23. Exhaust port 23
Other air that is not discharged from the air passes through the HEPA filter 5 for supply air, and is used as clean air in the work space 3.
Is blown out. The blown air 12 blown out into the work space 3 is clean air that does not contain bacteria / viruses 15. Therefore, the bacteria / viruses 15 handled in the work space 3 are contaminated with other germs and other bacteria / viruses 15. Protected without being.

A front suction slit 16 is formed on the front opening 10 side of the work table 2. By sucking outside air and air in a part of the work space 3 from the front suction slit 16,
An air curtain 11 is formed to block exchange of contaminants between the work space 3 and the air outside the safety cabinet 1. The safety cabinet 1 protects the bacteria / viruses 15 handled in the work space 3 from various germs outside the safety cabinet 1 by the blowing air flow 12 in the work space 3 and the inflow air flow 13 in the front opening 10, and the bacteria / viruses. 15 is confined in the work space 3 to prevent infection to workers.

In order to protect this sample from other germs while maintaining the ability to prevent infection to workers,
It is important that the blowout air velocity 12a of the airflow blown into the work space 3 and the inflow air velocity 13a of the air sucked from the front opening 10 are set to a predetermined speed. If the inflow wind speed 13a is too slow, the bacteria / viruses 15 handled inside the work space 3 may be pushed out by the blown air flow 12 in the work space 3 and leak out from the front opening 10. In conventional safety cabinets,
The air volume that the blower 6 is operating is constant. Therefore, with a conventional safety cabinet,
When the opening size of the front opening 10 is increased, the inflow wind speed 13a sucked from the front opening 10 is reduced, so that the user uses the front opening 10 with a constant width.

  FIG. 8 shows a state where the worker is using the safety cabinet.

When the front opening 10 is narrow, a research worker who is working with a hand from there narrows the range in which the arm can be moved, making it difficult to work. Is required. When the size of the front opening 10 is increased, by increasing the amount of exhaust air exhausted from the exhaust HEPA filter 4, the amount of suction air flowing in from the front opening 10 increases, and bacteria / viruses 15 in the work space 3. It is possible to maintain the inflow wind speed 13a that does not exit the safety cabinet 1. However, as shown in FIG. 8C, when a worker with a short height uses the safety cabinet 1 in which the front opening 10 has a large vertical dimension, the line of sight looking into the work space 3 overlaps with the front shutter lower end 9a. The work table 2 may be difficult to see.

As shown in FIG. 8 (a), in the case of a worker with a short height, if the front shutter 9 is closed and the front opening 10 is reduced in size, the operator's difficulty in working is eliminated, but with the same inflow air volume. Since the opening area becomes small, the inflow air speed 13a becomes too high, and germs outside the safety cabinet 1 may pass through the front suction slit 16 and enter the work space 3 to contaminate the sample in the work space 3. . As described above, in the safety cabinet, it is important for maintaining the performance to maintain the inflow wind speed at a predetermined value.

  FIG. 3 is a perspective view of the front opening size detecting means showing the first embodiment of the present invention.

作業空間幅寸法1300mm、作業空間幅寸法600mmの場合 In order to change the vertical dimension of the front opening 10, the front shutter 9 is moved up and down. In this embodiment, a limit switch 19 is provided beside the front shutter 9, and the operating air volume of the blower 6 is controlled so that the inflow air speed 13a becomes a predetermined air speed in accordance with the front opening dimension 10a.
Table 1 shows an example of control when the front opening size is changed to 250 mm and 200 mm.

Working space width 1300mm, working space 600mm

The working space 3 has a width dimension of 1300 mm, a depth dimension of 600 mm, and a front opening dimension of 2.
When the performance of the safety cabinet comes out at 50mm. Average inflow wind speed 13a is 0.55m
Assuming that the predetermined wind speed at which the function of the air curtain 11 is satisfied at / s, the air sucked from the front opening 10 = the amount of air exhausted from the exhaust port 23 is 10.7 m ³ / min. Also,
When the blowing air speed 12a blown into the work space 3 is 0.35 m / s, the blowing air amount is 16.4 m ³ / min. In this case, the total air volume that the blower 6 is operating is 10.
A ^{7m 3 /min+16.4m 3 /min=27.1m 3 / min} . In the case of the safety cabinet, the air volume blown into the work space 3 enters the pressure chamber 18 again and is blown into the work space 3 and thus circulates. A value obtained by dividing the circulating air volume by the total air volume operated by the blower 6 is called a circulation air rate, which is a demanding index in the safety cabinet. This circulation rate represents the ratio of air passing through the exhaust HEPA filter 4 and the supply HEPA filter 5. The circulation rate in operation with a front opening size of 250 mm in Table 3 is
60.5%. When the front opening dimension 10a is 250 mm, the lower limit switch 19b shown in FIG. 3 is ON, the upper limit switch 19a is ON, and the front opening dimension is determined to be 250 mm.

When the front shutter 9 is lowered with the same apparatus and the front opening size is 200 mm, the upper limit switch 19b is turned off and only the limit switch 19a is turned on, so that the front opening size is determined to be 200 mm. Naturally, the front opening dimensions 250mm and 200mm
At this position, a stopper is provided to prevent the front shutter from moving up and down inadvertently. As shown in Table 3, if the limit switch 19 detects a state where the front opening dimension is 200 mm, the blower 6 reduces the operating air volume to 21.7 m ³ / min. Since the circulation rate of the safety cabinet 1 in FIG. 2 does not change, the amount of air flowing into the front opening 10 and the amount of blown air in the work space 3 are also reduced by the same ratio, and the amount of inflow air is 8.6 m ³ / min. Is 13.1
It falls to m ³ / min. Naturally, the wind speed also decreases, the inflow wind speed 13a becomes 0.55 m / s, and the blown wind speed 12a becomes 0.28 m / s. Without this control, the front opening size is 200m
m, the front opening dimension 10a is 200 mm for the inflow air volume of 10.7 m ³ / min.
Therefore, the inflow wind speed 13a increases to 0.68 m / s, and in some cases, other germs may enter the work space 3.

This control is an example, and depending on the shape of the working space 3 of the safety cabinet 1 and the shape and position of the front suction slit 16, simply maintaining the inflow air velocity 13a = 0.55 m / s does not produce performance, and the front opening When the dimension 10a is 200 mm, the inflow wind speed 13a is 0.57 m.
A case of setting to / s also occurs. However, in this case as well, it is possible to control the operating air volume of the blower 6 to a predetermined air volume by detecting the front opening 10a by the limit switch 19, so that the performance of preventing the infection of the safety cabinet 1 is obtained. It becomes possible to set to the wind speed.

This prevents the safety cabinet 1 from being infected even if the front opening size 10a is changed according to the height of the user of the safety cabinet 1, the line of sight looking into the work table 2, and the movement of the operator's arm. Can be maintained.

FIG. 4 is a sectional structural view showing a safety cabinet showing a second embodiment of the present invention, and an overview of the safety cabinet is as shown in FIG.

An in-chamber damper 25 is provided in the pressure chamber 18. The air blown out from the blower 6 pressurizes the pressure chamber 18. The pressure chamber 18 includes an exhaust HEPA filter 4.
Since the air supply HEPA filter 5 is connected, the air is distributed to the exhaust port 23 side and the work space 3 side. The in-chamber damper 25 is attached for the purpose of controlling the air toward the exhaust HEPA filter 4 in the pressure chamber 18. When the in-chamber damper 25 is opened, the amount of air flowing toward the exhaust HEPA filter 4 is increased. Conversely, when the in-chamber damper 25 is closed, the amount of air flowing toward the supply HEPA filter 5 is increased. Depending on the front opening dimension 10a, the blower 6
In addition to controlling the total air volume, the in-chamber damper 25 can be moved to control the circulation rate of the inflow air speed 13a and the blown air speed 12a.

作業空間幅寸法1300mm、作業空間幅寸法600mmの場合 The control example of Table 2 is shown.

Working space width 1300mm, working space 600mm

As in the case of Table 1, the size of the work space 3 is 1300 mm in the width direction and 600 m in depth.
This is the case for m. When the front opening size 10a is 250 mm, the inflow wind speed 13a = 0.55 m
/ S, the blowing air speed 12a = 0.35 m / s. When the front opening dimension 10a is 200 mm, the total air volume is reduced with a constant circulation rate,
The blowout air speed 12a in the work space 3 also decreases, and depending on the shape of the safety cabinet 1, there may be cases where outside germs enter the work space 3 on the inflow air speed 13a. In that case, it is necessary to increase the blowing air speed 12a of the work space 3. In Table 2, according to the position of the front shutter 9, when the front opening dimension 10a is 200 mm, the in-chamber damper 25 is closed,
By restricting the air to the exhaust HEPA filter 4 side, reducing the inflow air volume to 8.6 m ³ / min, and changing the circulation rate from 60.5% to 65.6%, the blowing air speed in the work space 3 12a can maintain 0.35 m / s, and can maintain the infection prevention performance of the safety cabinet 1.

作業空間幅寸法1300mm、作業空間幅寸法600mmの場合 Table 3 shows another control example of the safety cabinet of Table 2.

Working space width 1300mm, working space 600mm

In the case of a safety cabinet, the air exhausted from the exhaust port 23 may be exhausted outdoors through a duct in a room where the safety cabinet 1 is installed (not necessarily exhausted outdoors). In that case, the duct is provided with an exhaust fan. In that case, even if the exhaust air volume of the safety cabinet 1 changes in accordance with the change in the front opening dimension 10a, it is often not provided to control the air volume of the exhaust fan of the duct. In that case, the exhaust air volume of the safety cabinet 1 needs to be constant. In that case, the front opening dimension 10a is set to 250.
When the air flow is changed from mm to 200 mm, the exhaust air flow rate = the inflow air flow rate is constant.
a may be too high from 0.55 m / s to 0.69 m / s with respect to the blown wind speed 12a in the work space 3. In that case, in order to maintain the blowing air speed 12a, the total air volume is set to 27.
Raised from 1 m ³ / min to 28.0 m ³ / min and increased circulation rate from 60.5% to 61.8%
It is possible to maintain the blown air velocity 12a in the work space 3 at 0.37 m / s so that other germs do not enter the work space 3 while keeping the exhaust air flow amount = inflow air amount constant. It becomes.

The predetermined wind speed required to prevent these infections depends on the shape of the safety cabinet. It is necessary to grasp this numerical value in advance and set the operating air volume of the blower 6 and the operating angle of the damper 25 in the chamber.

FIG. 5 is a sectional structural view showing a safety cabinet showing a third embodiment of the present invention, and an overview of the safety cabinet is as shown in FIG.
In order to control the aperture ratio of the front suction slit 16, a suction slit damper 21 is provided. When the suction slit damper 21 is opened, the air volume sucked from the front opening 10 =
The air volume exhausted from the exhaust port 23 increases, and conversely, when the suction slit damper 21 is closed,
It is possible to reduce the amount of air sucked from the front opening 10. With this configuration, the front opening 1 is matched with the ON / OFF signal of the limit switch 19 that detects the position of the front shutter 9.
It becomes possible to control the amount of air sucked from zero.

作業空間幅寸法1300mm、作業空間幅寸法600mmの場合 Table 4 shows a control example of the third embodiment.

Working space width 1300mm, working space 600mm

An example of the size of the work space 3 to be controlled is the same as in the first and second embodiments. Front opening size 250m
In the case of m, the suction slit damper 21 is in an open state. Front opening size is 200
When closed to mm, the limit switch 19 signal is received and the air volume of the blower 6 is set to 27.1 m.
³ / min to 25.0 m ³ / min, the amount of inflow air sucked from the front opening 10 is reduced, and the circulation air rate is changed from 60.5% to 65.6%, so that the blowout air speed in the working chamber 3 It becomes possible to control 12a and the inflow wind speed 13a to the predetermined | prescribed air volume from which the infection prevention performance of a safety cabinet comes out.

FIG. 6 is a cross-sectional structure diagram showing a safety cabinet showing a fourth embodiment of the present invention.
An exhaust fan 22 is provided downstream of the exhaust HEPA filter 4. By controlling ON / OFF of the exhaust fan 22 in the operating state of the safety cabinet 1, the amount of air pressurized in the pressure chamber 18 is distributed to the exhaust HEPA filter 4 and the supply HEPA filter 5. Can do. When the exhaust fan 22 is operated, the amount of air exhausted to the exhaust HEPA filter 4 increases. This is because the pressure on the exhaust HEPA filter 4 side decreases, and the air is directed to the exhaust HEPA filter 4 side. Limit switch 19 for detecting the position of the front shutter 9
An example of control combined with is shown below. Normally, the exhaust fan 22 is stopped when operating with the front opening dimension 10a being 200 mm. When the front shutter 9 is raised and the limit switch 19a detects that the front opening size is 250 mm, the exhaust fan 22 is moved. At this time, the exhaust air volume = inflow air volume increases, and a predetermined inflow air speed 13a can be maintained.

As described above, in the first to fourth embodiments, the two-stage control example of the front opening size of 200 mm and 250 mm has been shown.
Stepless control between 0 mm is also possible. In the case of stepless control, the opening position of the front shutter 9 is converted into a stepless signal such as electrical resistance, voltage, current, etc.
By controlling the rotation speed of the fan 6 fan steplessly, stepless control of the air volume is possible. Further, by installing a plurality of limit switches 19, multi-stage control is possible.

  FIG. 7 is a perspective view showing a safety cabinet showing a fifth embodiment of the present invention.

The height of the work table 2 from the floor (work table height 24) is made variable in accordance with the control of the blower 6 and the control of the circulation rate by changing the front opening size 10a of the first to fourth embodiments. Thereby, even if the height of the work table 2 and the front opening size 10a are changed in accordance with the height of the physique using the safety cabinet 1, the line of sight, and the movement of the arm, the bacteria / viruses 15 in the work space 3 can be removed from other germs Thus, it is possible to provide a safety cabinet 1 that prevents infection to research workers while protecting them.

The present invention provides an easy-to-use biohazard safety cabinet that corresponds to the height of an operator, has a field of view when looking at a workbench, and a movement of an arm that works.

DESCRIPTION OF SYMBOLS 1 ... Safety cabinet 1a ... Main body case 2 ... Work bench 2a ... Work space bottom surface 3 ... Work space 4 ... Exhaust HEPA filter 5 ... Air supply HAPA filter 6 ... Fan 7 ... Circulation flow path 8 ... Work space side wall surface 9 ... Front shutter 9a ... Front shutter lower end 10 ... Front opening 10a ... Front opening size 11 ... Air curtain 12 ... Blowing airflow 12a ... Blowing air velocity 13 ... Incoming airflow 13a ... Inflowing air velocity 14 ... Negative pressure contamination plenum 15 ... Bacteria / virus 16 ... Front suction slit 17 ... Back air suction port 18 ... Pressure chamber 19a ... Upper limit switch 19b ... Lower limit switch 20 ... Rectifying plate 21 ... Suction slit damper 22 ... Exhaust fan 23 ... Exhaust port 24 ... Work bench height 25 ... Inside chamber Damper

Further, in the safety cabinet, a work table for performing work, an air supply system for supplying clean air to the work space through the first air cleaning means by the air blowing means, a front shutter provided in front of the work space, and the work A front opening through which a user inserts an arm into the space; an exhaust system that sucks air from the front opening and exhausts the air out of the apparatus through the second air cleaning means by the blowing means; and the work table In the safety cabinet, which is provided on the front opening side of the front panel and has a front suction slit for sucking air from the front opening and air in the working space, air sucked from the front opening and air in the working space The front suction slit sucks the air curtain to form contaminants between the work space and the air outside the safety cabinet. When the front opening has the first opening size, the wind speed for sucking air from the front opening is the first suction wind speed, and the front shutter is lowered so that the front opening is the second. When the air velocity for sucking air from the front opening is the second suction air velocity when the opening size becomes the second air size, after the front shutter is lowered, the operating air volume of the air blowing means is lowered to reduce the second air velocity. If the inflow wind speed is too slow, it is handled inside the work space by controlling the intake air speed to a predetermined value that is the first suction air speed and setting the predetermined value that is the first suction air speed. The sample is pushed out by the blown airflow in the work space and leaks out from the front opening, and the front shutter is closed to reduce the front opening and reduce the opening area. For, by the front inflow wind speed is too fast, bacteria outside the safety cabinet, past the front suction slit enters to the working space, to prevent contaminating a sample of the working space <br It is characterized by that.

Claims (3)

An air supply system for supplying clean air to the work space through the first air cleaning means by the air blowing means;
A front shutter formed on the front surface of the work space, a front opening connected to the work space below the front shutter, and air is sucked from the front opening and is discharged out of the apparatus through the second air cleaning means. An exhaust system, a safety cabinet having a pressure chamber connected to the first and second air cleaning means and the air blowing means,
A safety cabinet characterized by controlling a blowing wind speed supplied to a work space according to an opening size of a front opening and a suction wind speed sucked from the front opening. 2. The safety cabinet according to claim 1, wherein the blowout wind speed supplied to the work space and the inflow wind speed sucked from the front opening are individually controlled according to the opening size of the front opening. The safety cabinet according to claim 1, wherein the position of the front opening from the floor can be changed according to the height of the worker.

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