Safety work device

Abstract

To restrain a chemical or a contaminant from flying into a workspace when a front shutter is closed in a safety work device.SOLUTION: A safety work device comprises a workspace, and a vertically movable front shutter on the front of the workspace. The front shutter forms a work opening part below the front shutter when it is displaced to the upper side. The safety work device comprises an exhaust port for exhausting air from the workspace, and an exhaust flow passage from the exhaust port. When the front shutter is closed, a case inside opening is formed above the front shutter.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to safety working devices such as safety cabinets and draft chambers.

Background Art

[0002] There is known a safety working device that is provided with a shutter on the front surface and enables safe work by exhausting the air inside. As an example thereof, Patent Document 1 discloses a safety cabinet having a working space and a shutter, and exhausting the air inside the working space.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the safety cabinet described in Patent Document 1, air flows in from the opening under the shutter during work, and the inflowed air is exhausted to the outside by a fan. Thereby, an appropriate air flow is formed in the working space. However, when the shutter is closed, the inside of the working space becomes excessively negative pressure, and an unexpected strong air flow occurs. For example, it is the inflow of air at high speed from a minute gap between the shutter and the workbench, or the inflow of air from the gap around the shutter. These air flows lead to the swirling of chemicals and contaminants remaining in the working space, resulting in the risk of in-cabinet contamination that contaminates the wall surface of the working space, and the risk of out-of-cabinet leakage through an unexpected route.

[0005] In order to solve the above problems, the present invention prevents excessive negative pressure in the working space even when the shutter is closed, and realizes the formation of a laminar flow in the working space. Thereby, it is possible to suppress the rise of chemicals and contaminants handled in the working space into the working space, and to suppress in-machine contamination and out-of-machine leakage.

Means for Solving the Problems

[0006] If an example of the safety working device of the present invention for solving the above problems is given, it is as follows.

[0007] A safety working device having a working space, a vertically movable front shutter on the front surface of the working space, the front shutter forming a working opening under the front shutter when shifted upward, an exhaust port for exhausting air from the working space, and an exhaust flow path from the exhaust port, wherein when the front shutter is closed, a housing inner opening is formed at the upper part of the front shutter.

Effects of the Invention

[0008] According to the present invention, even when the front shutter is closed, it is possible to suppress the rise of chemicals and contaminants handled in the working space into the working space, and to suppress in-machine contamination and out-of-machine leakage.

[0009] The further configuration and effects of the present invention will be clarified by the following full text of the specification.

Brief Description of the Drawings

[0010]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

Examples

[0011] FIG. 1A is an explanatory drawing when the front shutter is opened in a safety work device according to an embodiment of the present invention. For explaining structural features, it is explained in a schematic cross-sectional view.

[0012] A workbench 2 is configured on the lower housing 1. It has a back plate 3a on the back and an upper housing 5 on the upper side. It has a front shutter 4 on the front, and the area surrounded by 2, 3a, 5, and 4 becomes the work space. 3b is the back housing, and the space surrounded by 3a and 3b becomes the internal exhaust duct 22. In FIG. 1A, an example is shown in which the internal exhaust duct 22 is integrated with the safety work device to form the exhaust path 3, but the exhaust path may be configured separately from the safety work device in the form of separate piping or the like.

[0013] 50 is an external exhaust duct. It is a duct that connects to the internal exhaust duct 22 and guides the exhaust from the safety working device to the outside. 51 is an exhaust fan. In FIG. 1A, it is configured separately from the safety working device and can be arranged, for example, on the building side of a laboratory or a factory. Of course, it is not excluded to be provided on the safety working device side.

[0014] FIG. 1A shows a state where the front shutter 4 is open, that is, the front shutter 4 has moved upward to form an opening, and a front opening 24 is formed between the front shutter 4 and the workbench 2. At this time, due to the exhaust of air by the exhaust fan 51, a negative pressure is generated on the safety device side from the exhaust fan. As a result, an air flow is generated to eliminate the pressure difference. Thereby, the air from the outside passes through the front opening 24 and passes through the working space 23, for example, in the air flow 30. Then, as an example, it passes through the pre-filter 20 and is introduced into the internal exhaust duct 22. The introduced air passes through the HEPA filter 21, for example, and is finally exhausted by the exhaust fan 51 in the air flow 31.

[0015] Next, the maximum feature of this embodiment will be described with reference to FIGS. 1A and 1B.

[0016] As shown in both FIGS. 1A and 1B, a front housing 6 is formed at the upper front part of the front shutter 4. And an upper opening 10 is provided between the front housing 6 and the upper housing.

[0017] In the case of FIG. 1A, that is, when the front shutter 4 is in the open state and has moved upward in the figure, the front shutter 4 is configured to have an overlapping area with the upper housing 5. At this time, the existence of the upper opening 10 is separated from the working space 23 due to the overlap between the front shutter 4 and the upper housing 5.

[0018] In the case of FIG. 1B, that is, when the front shutter 4 is in the closed state by moving downward, the front opening 24 disappears and the air flow 30 disappears. At this time, as a result of the downward movement of the front shutter 4, the overlap between the front shutter 4 and the upper housing 5 is eliminated. This does not have to be a complete elimination, as long as at least part of the overlap is eliminated. As a result, a new opening 12 inside the housing is newly formed between the front shutter 4 and the upper housing 5. Thereby, a new air flow 32 is formed toward the working space 23 via the upper opening 10 and the opening 12 inside the housing. This new air flow 32 forms a downflow, and then, through the air flow 33 and the air flow 31, it is exhausted to the outside by the exhaust fan 51.

[0019] In this way, due to the movement of the front shutter, a downflow is automatically formed when the front shutter is in the closed state, and the generation of excessive negative pressure can be prevented, so that the flying up of drugs and contaminants into the working space is suppressed, and the contamination inside the machine and the leakage outside the machine can be suppressed.

[0020] In addition, it does not exclude providing a fan or a blower device above the working space.

[0021] As is clear from comparing FIG. 1A and FIG. 1B, the feature of the present invention is that by moving the front shutter, a new opening is formed above the front shutter, thereby enabling the formation of a downflow in the working space. Therefore, as long as this new structural concept is satisfied, various modifications and differences in configurations are all included in the scope of the disclosure of this embodiment.

[0022] In addition, the safety working device targeted by the present invention is applicable to various devices. As an example, it can be applied to a draft chamber, a safety cabinet, etc.

Embodiment

[0023] This embodiment has the same basic configuration as Embodiment 1. The difference between this embodiment and Embodiment 1 is that a rectifying plate 11 is additionally provided.

[0024] Figure 2A is a figure corresponding to Figure 1A. The difference is that the rectifying plate 11 is located above the working space 23, and the space between the rectifying plate 11 and the workbench 2 is the working space. When the front shutter 4 is in the open state of moving upward, the front shutter 4 is configured to have an overlapping area not only with the upper housing 5 but also with the rectifying plate 11 at the same time.

[0025] Next, Figure 2B is a figure corresponding to Figure 2B. In the closed state where the front shutter 4 moves downward, the front shutter 4 eliminates the overlapping area with the upper housing 5, but is still configured to have an overlapping area with the rectifying plate 11. As a result, the air flow 32 in Figure 1A flows into the working space 23 through the rectifying plate 11. Therefore, it is possible to prevent too much local difference in the air flow 32, and since the downflow wind speed can be enhanced, it is possible to further suppress the upward movement of chemicals and contaminants into the working space.

[0026] As the configuration of the rectifying plate 11, various configurations are applicable. For example, it can be a plate-like structure in which a large number of polygonal holes such as honeycombs are formed in metal, resin, etc., and an opening ratio of about several tens of percent is formed.

[0027] At this time, considering that if the opening ratio is too low, the air flow resistance becomes strong and the downflow becomes weak instead, and conversely, if the opening ratio is too high, the rectifying effect of the downflow decreases, it is desirable to set the opening ratio within an appropriate range.

[0028] As a desirable example, it is preferably configured as a punching plate with a large number of holes drilled planar on a plate-like structure such as stainless steel, and the opening ratio is about 20 - 40%, more preferably about 20 - 30%.

[0029] In addition, from the perspective of ease of manufacture, the aperture ratio of the flow straightening plate 11 is preferably planar and uniform over the entire surface.

[0030] On the other hand, from the perspective of strengthening the downflow in the vicinity of the front shutter 4, it is desirable to make the aperture ratio of the flow straightening plate 11 higher on the side of the front shutter 4 than on the side of the back plate 3a. However, even in this case, for the purpose of avoiding the generation of turbulent flow in the working space 23, etc., it is more desirable to change the aperture ratio within the range of 20 to 40%.

[0031] The configuration of the flow straightening plate is not limited to the above. As long as it is a plate-like structure with at least a part being open, it is included in the scope of the disclosure of this embodiment.

Example

[0032] This example is obtained by adding additional components to Example 2 and is premised on having the components described in Examples 1 and 2.

[0033] FIG. 3 is an explanatory diagram based on FIG. 2B. The difference between FIG. 3 and FIG. 2B lies in the fact that it has the illumination 15. This illumination 15 emits light downward and is for the purpose of illuminating the working space. Therefore, for the purpose of reducing the number of illuminations, it is desirable to be provided, for example, near the center.

[0034] FIG. 4 is an explanatory diagram of the main part of an example of the illumination 15 in FIG. 3. A large number of openings are formed in the flow straightening plate 11. And in a part of the flow straightening plate 11, an opening having a size larger than that of the large number of openings of the flow straightening plate 11 is formed. If the size of the large number of openings of the flow straightening plate 11 is W1 in the figure, it means an opening of W2 which is larger than that. Corresponding to this opening of W2, the illumination 15 is arranged. In FIG. 4, among the devices constituting the illumination 15, the light-emitting device part 15a of the LED is arranged so as to fit within W2.

[0035] This enables the light from the illumination 15 to be prevented from being blocked by the rectifying plate 11, thus realizing an improvement in the utilization efficiency of the light from the illumination 15. 15b is a substrate or a heat dissipation means. It corresponds to a printed circuit board for driving the LED, a heat sink for heat dissipation, etc. Power is supplied to 15a via 15b, and light is irradiated downward from the LED.

[0036] As disclosed in FIG. 3, even with the rectifying plate 11 present, illumination into the work space is possible. Further, by installing the illumination 15 with respect to the rectifying plate in the configuration of FIG. 4, the light utilization efficiency of the illumination 15 can be effectively utilized. Also, when the rectifying plate 11 is made of a metal such as stainless steel, it is possible to make the rectifying plate 11 also serve as an auxiliary heat sink for quickly dissipating the heat generated by the illumination 15. At this time, since the rectifying plate 11 is of a large size, it means that the illumination 15 is equipped with a powerful heat dissipation means, and it is also possible to realize an improvement in the lifespan of the illumination 15.

Example

[0037] This example adds additional components to Example 2 and is premised on having the components described in Examples 1 and 2.

[0038] FIG. 5 is an explanatory diagram based on FIG. 2B. The difference between FIG. 5 and FIG. 2B is that it has an electrostatic eliminator 16. This electrostatic eliminator 16 is positioned and arranged on the rectifying plate 11. This is because if the electrostatic eliminator 16 were arranged above the rectifying plate 11, the presence of the rectifying plate 11 would lead to a reduction in the performance of electrostatic elimination by the electrostatic eliminator 16.

[0039] FIG. 6 is an explanatory diagram of the main part of an example of the electrostatic eliminator 16 in this example and is an embodiment of an example using an ionizer.

[0040] The electrostatic eliminator 16 is installed positioned at the opening provided in the rectifying plate 11. In FIG. 6, an example using an example of an ion generator as the electrostatic eliminator 16 is being described. 16a is a needle electrode, 16b is a planar electrode, and it is an example of a so-called ionizer that generates ions by performing high-voltage discharge between this 16a and 16b. 16c is a support for the needle electrode 16a. A high voltage of different polarities is applied to 16a via an insulated wiring 16d and to 16b via an insulated wiring 16e.

[0041] The actual high voltage is supplied from a high-voltage generation circuit, but since it is of general content, detailed description is omitted. Note that what is necessary is the high voltage, and since the current itself approaches zero infinitely, it is possible to continue discharging for a long time. Note that the meaning of high voltages of different polarities also includes the case where one of the polarities is 0 or GND. Furthermore, if the power supply device is configured such that the polarity is not constant and changes midway, an antistatic effect for both positive and negative static electricity can be realized, which is more desirable.

[0042] In FIG. 6, 16a to 16e are shown as hollow, but actually, it is arranged on the rectifying plate 11 via a fixing member made of an insulator such as plastic for the purpose of fixing.

[0043] As in the configuration of FIG. 6, the electrostatic eliminator 16 is arranged corresponding to the opening of the rectifying plate 11 and is arranged so as to maintain the opening of the rectifying plate 11. Therefore, due to the air flow 32 in FIG. 2B, the ions generated by the electrostatic eliminator 16 are introduced into the working space by downflow.

[0044] Returning to FIG. 5, the position of the electrostatic eliminator 16 is not particularly limited, but more preferably, as disclosed in FIG. 5, it is preferably arranged shifted toward the front shutter 4 side from the center. This is because there is a high risk of adhesion of dust, contaminants, etc. due to static electricity inside the front shutter 4.

[0045] This is because while the other sides forming the working space can be made of metal to suppress electrostatic charging, the front shutter 4 needs to be transparent, so it will be composed of insulators such as glass or plastic. Therefore, the electrostatic eliminator 16 is shifted and arranged on the side of the front shutter 4 so that ions are intensively irradiated inside the front shutter 4, making it possible to efficiently remove static electricity from places where the need for static electricity removal is high and minimizing the number of electrostatic eliminators required.

[0046] It is desirable that the electrostatic eliminator 16 does not operate when the front shutter 4 is open, i.e., during operation, and instead operates when the front shutter 4 is closed. This can be achieved by providing sensors, switches, etc. that link the operation of the electrostatic eliminator 16 to the position and state of the front shutter 4.

[0047] As an example, Fig. 7 shows an example where switch means corresponding to the position of the front shutter 4 is provided. 17 is a switch, 17a is a movable contact that moves integrally with the front shutter, and 17b is a fixed contact fixed to the front housing 6. Its operation will be described with reference to Figs. 8A and 8B.

[0048] Fig. 8A is an explanatory diagram showing that the front shutter 4 is in the closed state and a high voltage is being supplied to the electrostatic eliminator 16. The movable contact 17a and the fixed contact 17b are in contact and in a conductive state between them. As a result, the voltage supplied to the fixed contact 17b is supplied to the electrostatic eliminator 16 as 18a.

[0049] Fig. 8B is an explanatory diagram showing that the front shutter 4 is in the open state and a high voltage is not being supplied to the electrostatic eliminator 16. The movable contact 17a moves upward simultaneously as the front shutter 4 moves upward. As a result, it separates from the fixed contact 17b and the two are in a non-conductive state. Thereby, the voltage supply to the electrostatic eliminator 16 is cut off.

[0050] The example in Fig. 8 is merely an example. When controlling the high-voltage supply to the electrostatic eliminator 16 using sensors or switches linked to the open or closed state of the front shutter, other implementation means may also be used and are included within the scope of this embodiment.

[0051] Also, during the operation of the sensors or switches, instead of continuous power supply, a configuration such as adding a limit switch where power supply stops after a preset time can be used to achieve a configuration where the static electricity is removed only for a certain period immediately after the front shutter 4 is closed, for example, immediately after the work is completed.

Embodiment

[0052] Fig. 9 shows a figure corresponding to Fig. 3 or Fig. 5 in this embodiment. This embodiment has the configurations of Embodiment 3 and Embodiment 4 simultaneously and is an example having both the illumination 15 and the electrostatic eliminator 16. As shown in Fig. 9, it is desirable that the positional relationship between the illumination 15 and the electrostatic eliminator 16 is configured such that the electrostatic eliminator 16 is positioned closer to the front shutter 4 side than the illumination 15. The reason is to simultaneously achieve the reasons explained in Embodiment 3 and Embodiment 4.

Embodiment

[0053] Fig. 10 is an explanatory diagram based on Fig. 9.

[0054] This embodiment is additionally used for the inventions disclosed in any of Embodiments 1 to 5. In this embodiment, it is characterized in that a damper is provided corresponding to the upper opening 10.

[0055] As an example of the damper, in Fig. 10, the damper is constituted by a combination of a lid 18 and a spring 19. This is provided corresponding to the upper opening 10.

[0056] In the state where the front shutter 4 is closed, that is, in the closed state, the pressure in the working space decreases due to the exhaust by the exhaust fan 51. Due to the difference between this pressure and the atmospheric pressure, a downward pressure is generated at the upper opening 10. Here, by providing a damper with a downward opening corresponding to the upper opening 10, since the atmospheric pressure is greater, the damper opens downward by the force due to the pressure difference, and air is introduced from the upper opening 10. At this time, since the damper operates due to the pressure difference, it is necessary to set its spring force weak.

[0057] Although not shown, in the open state of the front shutter, that is, in the state where the front shutter has moved upward, as shown in FIG. 1A, since the space is separated between the working space 23 and the upper opening 10, no pressure is applied to the damper, and thus the lid 18 closes by the force of the spring 19.

[0058] This damper can automatically close the upper opening 10 especially during long vacations or inspection work when the exhaust fan 51 is stopped for a long time, and thus it is possible to suppress the intrusion of dust and the like into the safety working device at that time.

Embodiment

[0059] FIG. 11 is an explanatory diagram corresponding to FIG. 2B. The difference from FIG. 2B is that it has an upper pre-filter 25. As a result, the air from the upper opening 10 flows into the working space 23 as the air flow 32 in the atmosphere after passing through the upper pre-filter 25. Therefore, it is possible to suppress the intrusion of dust and the like into the safety working device in the closed state of the front shutter 4.

[0060] Each of the above embodiments in the present invention can be used alone or in combination. In those cases as well, they are included in the scope of the invention of this embodiment.

[0061] Also, as long as the technical ideas detailed in each of the above embodiments are applied, modifications and some structural changes are also included in the scope of the present invention.

[0062] The invention disclosed in this specification, for example, one example is as follows. <Part 1> A working space, having a vertically movable front shutter on the front surface of the working space, When the front shutter is shifted upward, a working opening is formed under the front shutter, A safety working device having an exhaust port for exhausting air from the working space and an exhaust flow path from the exhaust port, A safety working device in which a housing opening is formed in the upper part of the front shutter when the front shutter is closed. <Part 2> In the safety working device according to <Part 1>, a safety working device having an upper opening above the housing opening. <Part 3> In the safety working device according to <Part 2>, when the front shutter is closed, air flows into the working space through the upper opening and the housing opening. <Part 4> In the safety working device according to <Part 3>, a safety working device having a flow rectifying plate above the working space. <Part 5> In the safety working device according to <Part 4>, A safety working device in which the opening ratio of the flow rectifying plate is higher on the side of the front shutter than on the back side of the safety working device. <Part 6> In the safety working device according to <Part 4>, a safety working device having lighting positioned on the flow rectifying plate. <Part 7> In the safety working device according to <Part 6>, the lighting is an LED, positioned and arranged in a hole formed in the flow rectifying plate, and the hole in which the LED is arranged is larger than the holes for flow rectifying purposes provided in a large number on the flow rectifying plate. <Part 8> In the safety working device according to <Part 4>, a safety working device having an electrostatic remover positioned on the flow rectifying plate. <Part 9> In the safety working device described in <The 8>, the electrostatic elimination device is a safety working device arranged by shifting it to the side of the front shutter with the rectifying plate. <The 10> In the safety working device described in <The 9>, the electrostatic elimination device is a safety working device that operates when the front shutter is closed. <The 11> In the safety working device described in <The 9>, the electrostatic elimination device is an ionizer having a needle electrode and a planar electrode. The needle electrode is positioned in the hole of the rectifying plate and arranged such that air flows around the needle electrode. <The 12> In the safety working device described in <The 4>, It has illumination and an electrostatic elimination device positioned on the rectifying plate, and the electrostatic elimination device is arranged on the side of the front shutter from the illumination. <The 13> In the safety working device described in <The 2>, corresponding to the upper opening, it has a damper that opens downward. <The 14> In the safety working device described in <The 2>, corresponding to the upper opening, it has an upper pre-filter.

Explanation of Signs

[0063] 1: Lower housing 2: Workbench 3a: Rear panel 4: Front shutter 5: Upper housing 6: Front housing 10: Upper opening 11: Rectifying plate 12: Opening inside the housing 15: Illumination 16: Electrostatic elimination device 20: Prefilter 21: HEPA filter 22: Internal exhaust duct 23: Working space 24: Front opening 25: Upper pre-filter 30, 31, 32, 33: Air flow 50: External exhaust duct 51: Exhaust fan

Claims

1. A work space, having a vertically movable front shutter on the front surface of the work space, when the front shutter is shifted upward, a work opening is formed below the front shutter, a safety work device having an exhaust port for exhausting air from the work space and an exhaust flow path from the exhaust port, a safety work device in which a housing opening is formed in the upper part of the front shutter when the front shutter is closed.

2. The safety work device according to claim 1, having an upper opening above the housing opening Safety work device.

3. The safety work device according to claim 2, in which air flows into the work space through the upper opening and the housing opening when the front shutter is closed.

4. The safety work device according to claim 3, having a flow rectifying plate above the work space.

5. The safety work device according to claim 4, in which the opening ratio of the flow rectifying plate is higher on the side of the front shutter than on the back side of the safety work device.

6. The safety work device according to claim 4, having lighting positioned on the flow rectifying plate.

7. The safety work device according to claim 6, wherein the lighting is an LED, positioned and arranged in a hole formed in the flow rectifying plate, and the hole in which the LED is arranged is larger than the holes for flow rectifying purposes provided in a large number on the flow rectifying plate.

8. The safety work device according to claim 4, having an electrostatic eliminator positioned on the flow rectifying plate.

9. The safety work device according to claim 8, in which the electrostatic eliminator is arranged by being shifted to the side of the front shutter with the flow rectifying plate.

10. The safety work device according to claim 9, in which the electrostatic eliminator operates when the front shutter is closed.

11. The safety work device according to claim 9, in which the electrostatic eliminator is an ionizer having a needle electrode and a planar electrode, the needle electrode is positioned and arranged in a hole of the flow rectifying plate, and the air is configured to flow around the needle electrode.

12. The safety work device according to claim 4, having lighting and an electrostatic eliminator positioned on the flow rectifying plate, and the electrostatic eliminator is arranged closer to the front shutter side than the lighting.

13. The safety working device according to claim 2, wherein, corresponding to the upper opening, the safety working device has a damper that opens downward.

14. The safety working device according to claim 2, wherein, corresponding to the upper opening, the safety working device has an upper pre-filter.

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