Isolator

Abstract

To provide an isolator capable of minimizing a contaminated area and a decontamination object area.SOLUTION: A fan filter unit, comprising: a working chamber in which a work handling harmful substances or a work generating harmful substances is performed; a return chamber separated from the working chamber by at least a ceiling wall and a rear wall of the working chamber; and an opening provided in the ceiling wall of the working chamber, An isolator comprising: a fan filter unit including a fan and a first filter; and a filter unit installed in an opening provided in a rear wall of the working chamber, the filter unit including a second filter, wherein air in the return chamber is blown downward into the working chamber through the first filter by driving the fan of the fan filter unit, and the air blown into the working chamber flows out to the return chamber through the second filter and is returned to the fan filter unit.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an isolator in which work is carried out in a work room in which substances that may affect the human body (hazardous substances) are handled, or work that requires the work room to be kept in a sterile or dust-free state. [Background technology]

[0002] Patent Document 1 discloses an isolator used for the above-mentioned purpose. The isolator has a work chamber (work space), and workers work in the work chamber through gloves attached to the front door of the work chamber. A return chamber, which is a non-work space, is provided above and behind the work chamber. A fan filter unit (an assembly equipped with a fan and a HEPA filter (or other high-performance filters such as a ULPA filter)) is provided on the ceiling of the work chamber. The fan filter unit blows HEPA-filtered air downward from the ceiling of the work chamber, and then the air flows out of an exhaust port provided on the rear panel of the work chamber into the return chamber (return passage), passes through the return chamber, returns to the fan filter unit, and is blown out from the fan filter unit into the work chamber. This air circulation keeps the air in the work chamber clean.

[0003] In the above-mentioned isolator, the space from the working chamber to the primary side of the HEPA filter is directly connected, which can lead to the risk of contaminants leaking from the working chamber to the return chamber. In this configuration, supplying a decontaminating fluid to the working chamber (the mainstream decontamination method) does not necessarily ensure that the return chamber is decontaminated. Therefore, when the isolator door is opened to expose the working chamber to the room after decontamination work, contaminants that flow back from the return chamber into the working chamber may leak into the clean room where the isolator is installed. If the contaminant is harmful to humans, special decontamination (e.g., decontamination of the entire working chamber and return chamber) is required to prevent this. Because devices such as fans are located in the return chamber, completely decontaminating the return chamber is both time-consuming and tedious. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-296889 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an isolator that can minimize the contaminated area and the area to be decontaminated. [Means for solving the problem]

[0006] According to the present invention, there is provided an isolator comprising: a work chamber in which work that handles hazardous substances or work that generates hazardous substances is performed; a return chamber isolated from the work chamber by at least a ceiling wall and a rear wall of the work chamber; a fan filter unit installed in an opening in the ceiling wall of the work chamber, the fan filter unit having a fan and a first filter; and a filter unit installed in an opening in the rear wall of the work chamber, the filter unit having a second filter; and wherein, by driving the fan of the fan filter unit, air in the return chamber is blown downward into the work chamber through the first filter, and the air blown into the work chamber passes through the second filter, flows out into the return chamber, and is returned to the fan filter unit.

[0007] Further features of the invention are set out in the dependent claims and in the detailed description. [Effects of the Invention]

[0008] According to the present invention, there is no risk of contaminants leaking from the working chamber to the return chamber, so only the working chamber needs to be decontaminated, which means that the contaminated area and the area to be decontaminated in the isolator can be minimized. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing the overall appearance of the isolator. [Figure 2] FIG. 2 is a front view of the isolator. [Figure 3] FIG. 3 is a longitudinal sectional view showing section III-III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view showing section IV-IV in FIG. 2. [Figure 5] FIG. 3 is a cross-sectional view showing section VV in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view showing the section VI-VI in FIG. [Figure 7] FIG. 1 is a schematic diagram showing the gas flow within an isolator, in which the baffle plate and the second filter are shown in positions different from their actual positions. [Figure 8] FIG. 4 is a simplified schematic diagram of a portion of FIG. 3 illustrating circulating airflow within the isolator. [Figure 9] FIG. 9 is a schematic diagram similar to FIG. 8, illustrating circulating airflow within a conventional isolator. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

[0011] The isolator 1 has a work chamber 10 at its front. The work chamber 10 is defined by a number of panels (plate-shaped walls) that are airtightly connected. An opening is provided in the front panel of the work chamber, and this opening can be airtightly closed by a transparent door 12. The door 12 can be opened and closed via a hinge 13 provided at its upper end, as shown in FIG. 3.

[0012] A plurality of gloves 14 (work gloves) are airtightly attached to the door 12. The gloves 14 are not shown in Fig. 1. A worker in front of the isolator 1 can work on objects in the work chamber 10 through the gloves 14 without coming into contact with the atmosphere inside the work chamber 10.

[0013] A return chamber (return passage) 16, which is a non-working space, is provided above and behind the working chamber 10. The return chamber is a space that is roughly inverted L-shaped when viewed in vertical cross section. The term "return chamber" is used to mean a chamber (passage) through which air that has been blown into the working chamber 10 from a fan filter unit 18 (described later) and then flows out of the working chamber 10 passes in order to be returned (returned) to the fan filter unit 18 (described later).

[0014] A fan filter unit 18 is attached to the ceiling panel (ceiling wall) 10a of the work room 10. The fan filter unit 18 is a disassembly assembly made up of one or more fans 181 and one or more HEPA filters (first filters) 182. In the illustrated embodiment, two HEPA filters 182 and three fans 181 are lined up in the left-right direction (see FIGS. 5 and 6).

[0015] As shown in Figures 3 and 5, a cover 183 that completely covers the two HEPA filters 182 is airtightly attached to the ceiling panel 10a, and three fans 181 attached to this cover 183 send air toward the two HEPA filters 182 housed in the space covered by the cover 183.

[0016] The two HEPA filters 182 are airtightly attached so as to respectively cover two rectangular openings (not shown) provided in the ceiling panel 10a of the work room 10. Air in the return chamber 16 is sucked in by the fan 181, passes through the HEPA filters 182, and is then blown downward into the work room 10 from the ceiling of the work room 10.

[0017] Near the underside of the ceiling panel 10a of the work room 10, an air outlet screen (air rectification port) 20 with many holes is provided to rectify the airflow blown out from the fan filter unit 18. The air outlet screen 20 creates a unidirectional airflow with a generally uniform airflow speed in the horizontal plane. The air outlet screen 20 can be made of a resin mesh with many fine holes. The air outlet screen 20 may also be made of a plate material such as a punched plate with micron-level holes, provided that it is confirmed that the unidirectional airflow can be ensured.

[0018] The rear panel (rear wall) 10b of the work chamber 10 has two rectangular openings (not shown), each fitted with two filter units. Each filter unit has a high-performance air filter, specifically a HEPA filter 22. The inlet surface of the HEPA filter 22 is parallel to the rear panel 10b and is generally flush with the rear panel 10b (although it may be slightly offset). In other words, the air intake surface of the filter is vertical. Air within the work chamber 10 passes through the HEPA filter 22 and flows out into the return chamber 16, then passes through the fan filter unit 18 again and is returned to the work chamber 10.

[0019] As described above, the air in the work room 10 is highly purified by circulating the air through the HEPA filter 182 and the HEPA filter 22.

[0020] As long as the HEPA filters 182, 22 are properly installed and airtight, air cannot pass between the return chamber 16 and the working chamber 10 without passing through the HEPA filters 182, 22. In other words, there is no path that allows air to flow between the return chamber 16 and the working chamber 10 by bypassing the HEPA filters 182, 22. This means that contaminants that were present in the working chamber 10 will not enter the return chamber 16.

[0021] The filter unit equipped with the HEPA filter 22 is preferably the filter device (SurePack System™) described in the applicant's Patent No. 5554553 (Invention Title: Filter Device and Replacement Method Thereof) and Patent No. 06993122 (Invention Title: Filter Unit for Air Purifier). This filter unit is attached to the rear panel 10b using screws. When removing a used filter unit from the rear panel 10b, the filter surface (the surface facing the work chamber) to which hazardous materials are attached can be covered with a sealing plate, allowing the filter unit to be replaced without scattering the captured hazardous materials into the surrounding area. The HEPA filter 182 may also have a similar configuration and attachment structure.

[0022] To prevent the air blown into the work room 10 from the HEPA filter 182 provided on the ceiling of the work room 10 from flowing directly into the HEPA filter 22 provided on the rear panel (a phenomenon known as a "short circuit"), a baffle plate 30 (see particularly FIGS. 4 and 6) is provided in front of the HEPA filter 22. When viewed from the front, the baffle plate 30 covers the entire or nearly the entire air intake surface of the HEPA filter 22. In the illustrated embodiment, one baffle plate 30 is provided for one HEPA filter 22.

[0023] The lower portion of each baffle plate 30 has a plurality of vertically elongated slits 34 (20 to 30 in the example shown in FIG. 6 ) arranged in the left-right (horizontal) direction. The height (length) of the slits 34 can be, for example, about 15 cm, and the width about 1 cm, but this is not limiting. When the baffle plate 30 is viewed from the front, the slits 34 are located at positions corresponding to the lower ends of the HEPA filters 22. The gap (space) 32 (see FIG. 4 ) between the rear panel 10b and the baffle plate 30 is closed at the top and left and right ends. In other words, the slits 34 serve as air passages, and air cannot flow into the gaps 32 from the main portion of the work chamber 10 (the portion of the internal space of the work chamber 10 excluding the gaps 32) without passing through the slits 34 (air passages).

[0024] As a result, air blown downward from the HEPA filter 182 into the work chamber 10 reaches the lower panel (surface of the workbench) of the work chamber 10 before entering the gap 32. This prevents a stagnant area (a region where air stagnates at zero or very low air flow velocity) from forming in the lower front area of ​​the work chamber 10 (near the door). Without the baffle plate 30, the aforementioned short circuit may occur under certain conditions, creating a stagnant area in the lower front area of ​​the work chamber 10 and resulting in the problem of the air in that area not being purified. Therefore, it is preferable to provide a baffle plate. The provision of the air outlet screen 20 also uniforms the velocity distribution of the air flow in the horizontal plane within the work chamber 10, which also contributes to preventing the aforementioned stagnant area from forming.

[0025] The short circuit refers to the flow indicated by the double arrows and labeled SC in Fig. 8. The stagnation region is the region surrounded by the dashed line and labeled ST in Fig. 8.

[0026] In addition, by using a baffle plate 30 in which a large number of slits 34 are distributed almost uniformly across the width of the (two) HEPA filters 22, the lateral flow velocity distribution of the air flowing from the main part of the work chamber 10 into the gap 32 can also be made roughly uniform.

[0027] A number of circular holes may be provided as air passages in place of the slits 34 in the lower part of the baffle plate 30. The shape of the holes is not limited to circles, and may be square or the like.

[0028] It is also possible to provide a configuration in which no slits or holes are provided in the baffle plate 30, but simply provide a gap (a relatively narrow gap extending continuously in the horizontal direction) between the lower end of the baffle plate 30 and a member immediately below the lower edge (for example, a panel that defines the work chamber 10, such as the lower panel of the work chamber), and use this gap as an air passage that connects the main part of the work chamber 10 (the part of the internal space of the work chamber 10 excluding the gap 32) to the gap 32. In this case, too, air cannot flow into the gap 32 from the main part of the work chamber 10 (the part of the internal space of the work chamber 10 excluding the gap 32) without passing through this air passage.

[0029] It is preferable that the thickness (front-rear width) of gap 32 is sufficiently smaller than the area of ​​gap 32 when viewed from the front. This increases the air flow rate within gap 32 and prevents the formation of an area where air stagnates within gap 32. In other words, air that flows into gap 32 through slits 34 flows into HEPA filter 22 without stagnating within gap 32. The thickness (front-rear width) of gap 32 can be, for example, approximately 5 to 10 cm.

[0030] As is clear from the above, there are no areas where air stagnates within the working chamber 10 (both in the space in front of and behind the baffle plate 30). In other words, clean air can be circulated throughout almost the entire working chamber 10.

[0031] 3 and 4, the baffle plate 30 is detachably attached by screws to a panel (wall) that defines the gap 32 together with the baffle plate 30. By removing the baffle plate 30, it becomes possible to operate the screws of a filter unit (such as the aforementioned SurePack System (trademark)) equipped with the HEPA filter 22, and the filter unit can be attached or detached.

[0032] An air supply unit 24 and an exhaust unit 26 are provided on the left and right sides of the upper portion of the return chamber 16 .

[0033] 3, the air supply unit 24 has an air supply duct 241 that communicates with the space outside the isolator 1, an air supply fan 242, and an air supply damper 243. The air supply flow rate can be adjusted by adjusting the rotation speed of the air supply fan 242 and / or the opening degree of the air supply damper 243.

[0034] 5 and 6, the exhaust unit 26 has an exhaust duct 261, an exhaust fan 262, a catalyst unit 263, and an exhaust damper 264. The catalyst unit 263 is used to decompose harmful substances contained in the exhaust gas (specifically, for example, hydrogen peroxide for decontamination) to make them harmless. The exhaust flow rate can be adjusted by adjusting the rotation speed of the exhaust fan 262 and / or the opening degree of the exhaust damper 264.

[0035] 1, an inlet 245 for the air supply unit 24 and an outlet 265 for the exhaust unit 26 are provided on the ceiling of the housing of the isolator 1. The inlet and outlet of each unit may be on the front, side, back, or bottom.

[0036] In the illustrated embodiment, the air supply unit 24 and the exhaust unit 26 are not provided with high-performance air filters such as HEPA filter units. The HEPA filters 182 and 22 are responsible for capturing all extremely fine particles. However, it is preferable to provide a pre-filter at the inlet 245 of the air supply duct 241 to remove relatively large dust particles. Alternatively, the air supply unit 24 and the exhaust unit 26 may be provided with a HEPA filter.

[0037] A pressure sensor (not shown) is provided in the working chamber 10. A controller (not shown) controls the operation of the air supply unit 24 and / or the exhaust unit 26 so that the pressure detected by the pressure sensor matches the target pressure in the working chamber 10. The pressure in the working chamber 10 can be increased or decreased by changing the relationship between the air supply flow rate and the exhaust flow rate. The air supply unit 24 and / or the exhaust unit 26 may be operated as needed and do not need to be operated all the time.

[0038] In order to check the state of the air inside the work chamber 10, a particle counter, an air sampler, an anemometer, a thermo-hygrometer, a gas concentration meter, etc. may be installed inside the work chamber 10.

[0039] Next, a brief description will be given of the decontamination function of the isolator 1. A pass box unit 40 is provided on the side of the work chamber 10 (on the right side in the illustrated example). The pass box unit 40 is provided with a decontamination gas supply unit 42. The installation position of the decontamination gas supply unit 42 may be anywhere in the entire apparatus and is not limited. The piping related to the decontamination gas supply unit 42 is shown in Figure 7, but only the essential parts will be described below and a description of the other parts will be omitted.

[0040] The decontamination gas supply unit 42 is configured to generate decontamination gas (here, a mixed fluid of hydrogen peroxide and air in the form of vapor, ultrafine particles, or mist) and blow it out into the space immediately below the blow-out screen 20 of the work chamber 10 (see arrow F1 in FIG. 7). The decontamination gas may be blown out into the space between the ceiling panel 10a of the work chamber 10 and the blow-out screen 20. When pressurized decontamination gas is blown into the work chamber 10, the decontamination gas permeates throughout the work chamber 10, decontaminating the inside of the work chamber 10. Furthermore, although hydrogen peroxide is used here as the decontamination agent, the decontamination agent is not limited to this, and any decontamination agent whose effectiveness and safety have been confirmed can be used.

[0041] A pass box 44 is provided in the middle of the pass box unit 40. The decontamination gas supply unit 42 can also supply decontamination gas to the pass box 44 (see arrow F2 in Figure 7). The pass box 44 has an airtight door 46 provided on the front of the isolator 1 and an airtight door 48 provided on the side panel (side wall) of the work chamber 10. Objects to be decontaminated can be placed inside the pass box 44 through the airtight door 46. Because the volume of the pass box 44 is significantly smaller than the volume of the work chamber 10, decontamination can be performed quickly. Decontaminated objects can be carried into or discarded from the work chamber 10 through the airtight door 48, and can be repeatedly carried in and out by simply decontaminating the pass box 44 without opening the isolator 1. This improves the efficiency of the decontamination work.

[0042] The decontamination gas used in the work chamber 10 can be exhausted by the exhaust unit 26 via the return chamber 16. At this time, the decontamination gas is rendered harmless by the catalyst unit 263 of the exhaust unit 26. If the decontamination gas contains hydrogen peroxide, the catalyst unit 263 decomposes the hydrogen peroxide into water and oxygen, which are harmless to the human body. The decontamination gas used in the pass box 44 can be exhausted from inside the isolator 1 via the same route as above or an exhaust route dedicated to the pass box 44, after being rendered harmless by the catalyst unit.

[0043] The effects of the above embodiment will be explained in comparison with a typical conventional example. In the conventional example shown schematically in Fig. 9, three HEPA filters are provided: a HEPA filter attached to the air supply fan, a HEPA filter in the fan filter unit, and a HEPA filter attached to the exhaust fan. Air in the non-working area (located in a position corresponding to the return chamber 16 in the embodiment) passes through the HEPA filter in the fan filter unit and flows into the working chamber, then flows out from the working chamber to the non-working area, passes through the fan filter unit again, and circulates so as to flow into the working chamber 10.

[0044] In the above embodiment, as shown schematically in Figure 8, the air in the return chamber 16 flows into the working chamber 10 through the HEPA filter 182 of the fan filter unit 18, flows out into the return chamber 16 through the HEPA filter 22, and then circulates again through the HEPA filter 182 of the fan filter unit 18 into the working chamber 10.

[0045] Due to the difference in filter arrangement between the conventional example and the present embodiment, the present embodiment has the following advantageous effects, which will be explained with particular reference to Figures 8 and 9. In Figures 8 and 9, the air flow is indicated by solid arrows.

[0046] As is clear from the schematic diagram shown in Figure 9, in the conventional example, the working chamber and the return chamber are connected by an opening in the rear panel, allowing contaminants in the working chamber to flow into the return chamber. Therefore, when decontaminating the working chamber by air circulation, the return chamber must also be decontaminated. Because the volume of the space to be decontaminated is large, decontamination by air circulation takes time. Furthermore, because decontamination gas is trapped in the HEPA filter, a large amount of decontaminant is required. These factors require a long aeration time (intake and circulation of fresh air, and air containing decontamination gas is detoxified through a catalyst before being exhausted), which increases the fan's power consumption. Furthermore, if contaminants remain in the return chamber after the working chamber is no longer in use, or if contaminants remain in the return chamber after decontamination of the working chamber is completed, opening door 12 may result in contaminants leaking from the return chamber through the working chamber into the clean room where isolator 1 is installed.

[0047] In contrast, as is clear from the schematic diagram shown in FIG. 8 , in this embodiment, all of the above problems are resolved. In this embodiment, the work chamber (work space) 10 and the return chamber 16 (non-work space) are separated by two HEPA filters. Therefore, contaminants in the work chamber 10 do not flow into the return chamber 16. Furthermore, contaminants in the return chamber 16 (e.g., those taken in from the outside air) do not flow into the work chamber 10. When aerating the air in the work chamber by air circulation, the air passes through the HEPA filter twice per circulation, so the aeration time is short and the fan power consumption can be reduced. When decontaminating the work chamber 10 after using the isolator 1, only the work chamber 10 needs to be decontaminated. After decontamination of the work chamber 10 is completed, opening the door 12 will prevent contaminants from flowing out.

[0048] The present invention is not limited to the above-described embodiments, and can be modified in various forms without departing from the scope and spirit of the claims. [Explanation of symbols]

[0049] 10 Workroom 10a Workroom ceiling and wall (panel) 10b Rear wall (panel) of workroom 16 Return Chamber 18 Fan filter unit 181 fans 182 First filter (HEPA filter) 22 Second filter (HEPA filter) 30 baffle plate

Claims

1. A workroom where work involving the handling of substances that may affect the human body (hazardous substances) or work that requires the interior to be kept sterile or dust-free is carried out. a return chamber isolated from the working chamber by at least a ceiling wall and a rear wall of the working chamber; a fan filter unit installed in an opening provided in a ceiling wall of the work room, the fan filter unit having a fan and a first filter; a filter unit installed in an opening provided in a rear wall of the work chamber, the filter unit having a second filter; Equipped with An isolator configured such that, by driving the fan of the fan filter unit, air in the return chamber is blown downward into the working chamber through the first filter, and the air blown into the working chamber passes through the second filter and flows out into the return chamber and is returned to the fan filter unit.

2. a baffle plate provided in front of the rear wall and in front of the filter unit; The baffle plate divides the space within the working chamber into a first space in front of the baffle plate where the work is performed, and a second space between the baffle plate and the rear wall, 2. The isolator according to claim 1, wherein air flows from the first space to the second space only through an air passage provided in the baffle plate or an air passage formed between an edge of the baffle plate and a member facing the edge.

3. 3. The isolator according to claim 2, wherein the air passages provided in the baffle plate are formed by a plurality of through holes arranged in a horizontal direction and drilled in a lower portion of the baffle plate.

4. 4. The isolator according to claim 2, wherein the air intake surface of the second filter extends vertically.

5. 3. The isolator according to claim 2, wherein the baffle plate is detachable from the rear wall, and the filter unit having the second filter can be removed from the rear wall from inside the working chamber with the baffle plate removed.

6. an air intake port for taking air outside the isolator into the return chamber; an air supply fan that takes in air outside the isolator through the air supply port and sends it into the return chamber; an exhaust port for discharging air from the return chamber to the outside of the isolator; an exhaust fan that exhausts the air in the return chamber to the outside of the isolator through the exhaust port; 10. The isolator of claim 1 further comprising:

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