JP2015224819A - Anti-contamination safety cabinet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-contamination safety cabinet capable of preventing contamination during usage of a chamber for work and further preventing contamination around surroundings.SOLUTION: This invention is operated in such a way that, during applicable operation at a safety cabinet 10, air is supplied to a chamber 12 by the first blower 23 and at the same time the air is flowed into the first to third air flow passages 13 to 15 to cause a part of the air to be flowed in again to the chamber 12 and the residual air is flowed from the second air flow inlet 20 to the second duct 18 and further air flowing in the second duct 18 is supplied by the second blower 24 toward a floor 46 of a space 16, the air flowing in the second duct 18 is supplied by the third blower 25 toward the floor 46 of the space 16 and then mixtures of air flowing toward the floor 46 and air flowing from the second flow inlet 20 to the second duct 18 is supplied again toward the floor 46 of the space 16.

Description

  The present invention relates to a safety cabinet capable of preventing contamination that prevents contamination between a working chamber and the outside.

  A working chamber 102 having a predetermined volume having a front opening 101 that is opened and closed by the front shutter 100, an air inflow opening 103 formed in the vicinity of the front opening 101, and an air inflow opening located below (directly below) the working chamber 102. 103, a second air flow path 105 connected to the first air flow path 104 located behind (immediately after) the working chamber 102, and above (directly above) the working chamber 102. The third air flow path 106 that is positioned and connected to the second air flow path 105, the supply HEPA filter 107, the exhaust HEPA filter 108, and the clean air that has flowed through the supply HEPA filter 107 is a working chamber. The working chamber is supplied with clean air which is supplied from the upper side to the lower side of 102 and through which the exhaust HEPA filter 108 flows. 02, a safety cabinet 110 having a blower fan 109 that exhausts to the outside and controlling the blowing air speed supplied to the working chamber 102 according to the opening size of the front opening 101 and the suction air speed sucked from the front opening 101 is disclosed. (See Patent Document 1).

  In this safety cabinet 110, as shown in FIG. 10, the clean air that has passed through the air supply HEPA filter 107 during use when the user 111 lifts the front shutter 100 to open the front opening 101 is used as the work chamber 102 (work space. ) And an air-fuel mixture of clean air and outside air entering from the front opening 101 flows into an air inflow opening 103 formed below the front opening 101, and the air-fuel mixture flows from the first air flow path 104 to the first air passage 104. 2 It flows into the blower fan 109 while flowing into the air flow path 105.

  A part of the air-fuel mixture flowing into the blower fan 109 flows through the exhaust HEPA filter 108 to become clean air, exhausted to the outside of the safety cabinet 110, and the remaining part flows into the air supply HEPA filter 107 to work again. The chamber 102 is supplied with air. The air exhausted from the exhaust HEPA filter 108 is discharged into the chamber 112 in which the safety cabinet 110 is installed. Outside air that has passed through the HEPA filter is supplied to the chamber 112 from the outside air inlet 113. In the safety cabinet 110, microorganisms such as bacteria and viruses and fine dust are filtered by the air supply HEPA filter 107 and the exhaust HEPA filter 109, so that the clean air can be exhausted into the chamber 112 and the clean air Can be supplied to the working chamber 102.

JP 2013-51962 A

  In the safety cabinet 110 disclosed in Patent Document 1, the air that has flowed through the working chamber 102 during use with the front shutter 100 pulled up to open the front opening 101 leaks out from the front opening 101 of the chamber 102 and diffuses. In order to avoid this, an air-fuel mixture of air flowing through the chamber 102 and room air entering from the front opening 101 is caused to flow from the air inflow opening 103 into the first to third air flow paths 104 to 106.

  However, the movement of the user's 111 hand or arm inserted into the working chamber 102 from the front opening 101 disturbs the airflow in the vicinity of the front opening 101, thereby causing the chamber 102 to flow as indicated by an arrow L 1 in FIG. There may be a case where a part of air leaks from the front opening 101 to the outside of the chamber 102 (the chamber 112 in which the safety cabinet 110 is installed). When a part of the air flowing through the working chamber 102 leaks into the chamber 112 where the safety cabinet 110 is installed, microorganisms such as bacteria and viruses existing in the chamber 102 flow out to the outside, and not only the user 111 but also the cabinet 110. The entire area of the room 112 in which is installed is contaminated. Therefore, in order to prevent contamination strictly, only one safety cabinet 110 can be installed in one room.

  It should be noted that the cleanliness level inside the safety cabinet 110 is grade A, and a room 112 with a cleanliness level of grade B is required to maintain it. Since it is necessary to provide a Grade B room 112, a plurality of rooms such as a grade C or grade D cleaning room, a deguning room, a buffer area, and a supply room must be prepared around the room 112. In order to install one safety cabinet 110, a large-scale facility must be constructed. Furthermore, a large amount of energy must be consumed in order to maintain the operation status of the facility, and energy saving cannot be realized.

  It is an object of the present invention to provide a safety cabinet capable of preventing contamination during use of a working chamber and preventing contamination by microorganisms such as bacteria and viruses. Another object of the present invention is that it is not necessary to construct a plurality of rooms having a cleanliness level of grade B or C for installation, and it is possible to install a plurality of safety cabinets in one room and to save energy. It is an object of the present invention to provide a safety cabinet capable of preventing contamination.

  The premise of the present invention for solving the above-mentioned problems is that a working chamber having a predetermined volume having a front opening that is opened and closed by a front shutter and having a first filter installed at the top thereof, is positioned below the working chamber. A first air passage extending in the front-rear direction, a second air passage located behind the working chamber and connected to the first air passage and extending in the up-down direction, and a second air passage located above the working chamber. A third air flow path that is connected to the air flow path and extends in the front-rear direction, and a first blower that allows air to flow downward from above the working chamber, prevent contamination between the working chamber and the outside. It is a safety cabinet that can prevent contamination.

  As a feature of the present invention based on the above premise, the safety cabinet is located behind the second air flow path and extends in the up-down direction, and is connected to the first duct and above the third air flow path. An air circulation second duct that is positioned and extends in the front-rear direction, a work space of a predetermined volume that is located in front of the work chamber and that is used by a user who uses the work chamber, and extends below the first air flow path. A first air inlet for allowing air to flow in from the bottom of the first duct, a second air inlet for allowing air to flow from the third air flow path to the second duct, and a second air inlet flowing from the third air flow path to the second duct. A second filter that filters air; a first air supply port that is located in the rear and central areas of the work space and supplies air to the work space; and a first air supply port that is installed in the second duct From the work space A second blower for supplying air toward the surface, a third filter for filtering air supplied to the work space by the second blower, and air in the work space located in front of the first air supply opening And a third blower that is installed in the second duct and supplies air from the second air supply port toward the floor of the work space. When the user exists in the work space and the front opening of the work chamber is open, the air flowed through the first filter by the first blower flows from the upper side to the lower side of the work chamber, and The air is introduced from the vicinity of the front opening into the first air flow path while being guided from the second air flow path to the third air flow path so that a part of the air flows again into the working chamber, and the remainder of the air To the second filter The air flowing from the second air inlet into the second duct while flowing, and the air flowing through the second duct through the third filter by the second blower from the first air supply port to the floor surface of the work space The air flowing in the second duct is supplied from the second air supply port toward the floor of the work space by the third blower, and the air directed toward the floor is supplied to the first air flow. The air-fuel mixture of the air flowing into the second duct from the second air inlet and the air flowing into the second duct from the first air inlet toward the second duct is introduced toward the floor surface. It is to carry out the use operation to supply air again.

  As an example of the present invention, in the use operation, the wind speed of the air supplied from the third blower is faster than the wind speed of the air supplied from the second blower.

  As another example of the present invention, in the safety cabinet, when a user is present in the work space and the front opening of the work chamber is closed by the shutter, the air flowing in the second duct is thirdly discharged by the second blower. While flowing through the filter, air is supplied from the first air supply port toward the floor surface of the work space, and air flowing through the second duct is supplied from the second air supply port to the floor surface of the work space by the third blower. Then, the air flowing toward the floor is introduced into the second duct while flowing into the first duct from the first air inlet, and the air flowing from the first duct into the second duct is directed toward the floor. Then, prepare for re-supplying.

  As another example of the present invention, in the preparatory operation, the wind speed of the air supplied from the third blower is faster than the wind speed of the air supplied from the second blower.

  As another example of the present invention, in the preparatory operation, the wind speed of the air supplied from the second blower is faster than the wind speed of the air supplied from the second blower in the use operation.

  As another example of the present invention, in the safety cabinet, when the user does not exist in the work space and the front opening of the work chamber is closed by the shutter, the air is not supplied from the third blower, The air flowing through the two ducts is supplied from the first air supply port toward the floor surface of the work space while the air flowing through the duct is passed through the third filter by the second blower, and the air directed toward the floor surface is supplied to the first air inlet port. The idling operation is performed in which the air that has flowed into the first duct from the first duct is caused to flow into the second duct, and the air that has flowed into the second duct from the first duct is supplied again toward the floor surface.

  As another example of the present invention, in the idling operation, the wind speed of the air supplied from the second blower is slower than the wind speed of the air supplied from the second blower in the use operation and the preparation operation.

  As another example of the present invention, in the preparatory operation and the idling operation, the air passed through the first filter by the first blower is caused to flow from the upper side to the lower side of the working chamber, and the air is made near the front opening. Then, the air is introduced from the second air flow path to the third air flow path while flowing into the first air flow path, and the air is again flowed into the working chamber.

  As another example of the present invention, the safety cabinet includes first detection means for detecting entry or exit of the user into the work space, and second detection means for detecting opening or closing of the front opening. In the cabinet, the first detection means detects the user's entry, and the second detection means detects the opening of the front opening, and the use operation is performed. The first detection means detects the user's entry. When the second detection means detects the closing of the front opening, the preparatory operation is performed. The first detection means detects the exit of the user, and the second detection means detects the front opening being closed. If it is detected, the idling operation is performed.

  As another example of the present invention, the safety cabinet has a fourth filter that filters air supplied by the third blower, and a fifth filter that filters air flowing into the first duct from the first air inlet. including.

  As another example of the present invention, the safety cabinet includes side panels positioned on both lateral sides of the work space. In the safety cabinet, the work space is surrounded by the first and second ducts, the side panel, and the floor surface. And the opposite side of the working chamber is open.

  As another example of the present invention, the second air supply port is a slit extending between the one side panel and the other side panel across the work space, and the air supplied from the third blower is By passing through the slit, an air curtain is formed that blocks the entry of air from outside the work space.

  As another example of the present invention, in a safety cabinet, the air cleanliness level inside the working chamber is Grade A, the air cleanliness level in the work space is Grade B, and the air is cleaned outside the work space. The degree level is grade C or grade D.

  According to the safety cabinet capable of preventing contamination according to the present invention, in the use operation, the air flowing through the second duct is passed through the third filter by the second blower, and the work space is reduced from the first air supply port. Air is supplied toward the floor surface, and air flowing through the second duct is supplied from the second air supply port toward the floor surface of the work space by the third blower, and the air directed toward the floor surface is firstly supplied. An air-fuel mixture of air flowing into the second duct while flowing into the first duct from the air inlet, and air flowing into the second duct from the second air inlet and air flowing into the second duct from the first duct The air supplied from the first air supply port toward the rear area of the work space and the floor surface of the central area is supplied to the first duct from the front of the front opening of the work chamber. When the air flows in, the air forms a first air barrier, and the air supplied from the second air supply port toward the floor surface in the front area of the work space flows from the first air supply port to the work space. When the air supplied toward the floor of the air flows into the first duct from the front, the air forms a second air barrier, and the user's hand inserted into the working chamber through the front opening Even if a part of the air flowing through the chamber leaks out of the front opening through the front opening, the air flows into the first duct through the first and second air barriers even if the air movement in the vicinity of the front opening is disturbed by the movement of the arm. It is possible to prevent leakage and diffusion of air leaking outside the chamber to the outside of the safety cabinet. The safety cabinet prevents leakage of air leaking outside the chamber during use of the working chamber to the outside of the safety cabinet, so that the air leaking outside the chamber leaks outside the safety cabinet. Nation can be prevented, and surrounding contamination by microorganisms such as bacteria and viruses and fine dust can be prevented. The safety cabinet causes the air passed through the first filter by the first blower to flow from the upper side to the lower side of the working chamber and flows the second air from the vicinity of the front opening into the first air flow path. Since part of the air is led from the air flow path to the third air flow path and flows again into the working chamber, microorganisms such as bacteria and viruses and fine dust are collected by the first filter during use of the chamber. The clean air can always flow into the chamber and the chamber can be kept clean, and the air passed through the third filter by the second blower toward the floor of the work space. Since air is supplied, clean air in which microorganisms such as bacteria and viruses and fine dust are collected by the third filter can be supplied to the working space at all times. It is possible to keep the work space in a clean state.

  In the use operation, the safety cabinet capable of preventing contamination in which the wind speed of the air supplied from the third blower is faster than the wind speed of the air supplied from the second blower, the second speed of the air supplied from the third blower is the second. By making it faster than the air velocity of the air supplied from the blower, the barrier function of the second air barrier formed from the air supplied from the second air supply port can be improved. Air that has leaked to the outside or air supplied from the first air supply port does not leak outside the air supplied from the third blower (second air barrier), and the working chamber is opened from the front opening. Even if the air leaked to the outside passes through the first air barrier formed by the air supplied from the first air supply port, the air is caused to flow into the first duct by the second air barrier. It is possible, it is possible to prevent leakage or diffusion to the outside of the safety cabinet of air leaked to the outside of the chamber. The safety cabinet reliably prevents the leakage and diffusion of air leaking outside the chamber during use of the working chamber to the outside of the safety cabinet, so that air leaking outside the chamber leaks outside the safety cabinet. Contamination can be prevented and surrounding contamination by microorganisms such as bacteria and viruses and fine dust can be prevented. Since the safety cabinet supplies air that has been passed through the third filter by the second blower toward the floor surface of the work space, microorganisms such as bacteria and viruses and fine dust are collected by the third filter. Clean air can be constantly supplied to the work space, and the work space can be kept clean.

  When the user exists in the work space and the front opening of the working chamber is closed by the shutter, the first air supply port is made to flow the air flowing through the second duct to the third filter by the second blower. From the second air supply port, the air flowing through the second duct was supplied from the second air supply port toward the floor of the work space and directed toward the floor. Contamination for carrying out a preparatory operation in which air is introduced from the first air inlet into the second duct while flowing into the second duct, and the air that has flowed from the first duct into the second duct is supplied again toward the floor. The preventable safety cabinet is configured such that air supplied from the first air supply port toward the rear area of the work space and the floor surface of the central area is first from the front of the front opening of the work chamber. When the air flows into the duct, the air forms a first air barrier, and the air supplied from the second air supply port toward the floor of the front area of the work space is supplied from the first air supply port. Even if the user forms a second air barrier by flowing into the first duct from the front of the air supplied toward the floor of the work space and the user exists in the work space, Microorganisms such as bacteria and viruses and fine dust that are released can be introduced into the first duct by the first and second air barriers, and the air that has been passed through the third filter by the second blower is supplied to the work space. Since air is supplied toward the floor surface, clean air in which microbes and microbes such as bacteria and viruses emitted from the user are collected by the third filter is constantly supplied to the work space. It can be, it is possible to maintain the working space in a clean state in the preparation operation.

  In the preparatory operation, the safety cabinet capable of preventing contamination in which the wind speed of the air supplied from the third blower is higher than the wind speed of the air supplied from the second blower is the second air velocity of the air supplied from the third blower. By making it faster than the wind speed of the air supplied from the blower, the barrier function of the second air barrier formed from the air supplied from the second air supply port can be improved. The air supplied from the vent is not leaked outside the air supplied from the third blower (second air barrier), the user exists in the work space, and the user is crowned in the work space. Even if microorganisms and fine dust such as bacteria and viruses are released from the user by performing degaunting, the microorganisms and fine dust are discharged to the first duct by the second air barrier. It can be quite influx. Since the safety cabinet supplies air that has been passed through the third filter by the second blower toward the floor surface of the work space, the cleanliness in which microorganisms and dust released from the user are collected by the third filter is collected. Fresh air can be constantly supplied to the work space, and the work space can be kept clean in the preparatory operation.

  In the preparatory operation, the safety cabinet capable of preventing contamination in which the wind speed of the air supplied from the second blower is faster than the wind speed of the air supplied from the second blower in the use operation is the air speed of the air supplied from the second blower. Is made faster during the preparatory operation than during the use operation, thereby improving the barrier function of the first air barrier formed from the air supplied from the first air supply port as compared with the use operation. Even if the user is present in the work space and the user performs gouning or degaunting in the work space, microorganisms such as bacteria and viruses and fine dust are released from the user, Dust can surely flow into the first duct by the first air barrier. Since the safety cabinet supplies air that has been passed through the third filter by the second blower toward the floor surface of the work space, the cleanliness in which microorganisms and dust released from the user are collected by the third filter is collected. Fresh air can be constantly supplied to the work space, and the work space can be kept clean in the preparatory operation.

  When the user does not exist in the work space and the front opening of the working chamber is closed by the shutter, the air flowing through the second duct is supplied by the second fan without supplying air from the third fan. The air is supplied from the first air supply port toward the floor of the work space while flowing through the three filters, and the air directed toward the floor is introduced into the first duct from the first air inlet to the second duct. A safety cabinet capable of preventing contamination that performs an idling operation in which the air flowing into the second duct from the first duct is supplied again toward the floor surface is passed through the third filter by the second blower. The first air supply is performed by supplying air from the space to the first and second ducts while supplying air toward the floor area in the rear area and the central area of the work space. Since the air supplied from the air forms the first air barrier, it is possible to prevent the leakage and diffusion of air from the work space to the outside of the safety cabinet, and the third filter prevents microbes such as bacteria and viruses and fine particles. Therefore, clean air with collected dust can be constantly supplied to the work space, and the work space can be kept clean in idling operation.

  The safety cabinet capable of preventing contamination in which the wind speed of the air supplied from the second blower in the idling operation is slower than the wind speed of the air supplied from the second blower in the use operation and the preparation operation is supplied from the second blower in the idling operation. By making the wind speed of the air to be aired slower than the wind speed of the air supplied from the second blower in the use operation and the preparation operation, a smaller amount of air is supplied to the work space during the idling operation than during the use operation and the preparation operation. Therefore, energy consumption can be reduced in idling operation without using a safety cabinet, and energy saving can be realized. The safety cabinet can always supply clean air in which microbes such as bacteria and viruses and fine dust are filtered by the third filter to the work space, and keep the work space clean in idling operation. it can.

  In the preparatory operation and idling operation, the air passed through the first filter by the first blower flows from the upper side to the lower side of the working chamber and flows into the first air flow path from the vicinity of the front opening. A safety cabinet capable of preventing contamination by guiding the air from the second air flow path to the third air flow path and flowing the air into the work chamber again while the work chamber is not used in the preparation operation and the idling operation. Clean air, in which microorganisms such as bacteria and viruses are filtered by the first filter, can always flow into the working chamber, and the chamber can be kept clean. In the safety cabinet, the inside of the chamber is kept clean in the preparation operation and the idling operation, so that the working chamber can be always used and the chamber can be used immediately.

  A first detection means for detecting entry or exit of the user into the work space; and a second detection means for detecting opening or closing of the front opening, and the entry of the user is detected by the first detection means. When the opening of the front opening is detected by the second detection means, the use operation is carried out, the entry of the user is detected by the first detection means, and the closing of the front opening is detected by the second detection means A safety cabinet capable of preventing contamination when performing a preparatory operation and detecting the exit of the user by the first detection means and performing the idling operation when the closing of the front opening is detected by the second detection means The first detection means automatically detects the user entering or leaving the work space, and the second detection means opens the front opening. Or, the closure is automatically detected, and the use operation, the preparation operation, and the idling operation are performed by each detection signal of the detection means, so that the user does not need to switch to the use operation, the preparation operation, and the idling operation by itself. In addition to improving usability, it is possible to prevent mistakes in switching each operation by the user, and to improve the safety of the cabinet. The safety cabinet is automatically operated when the first detection means detects the user's entry and the second detection means detects the opening of the front opening, so that the safety cabinet leaks out of the working chamber. Contamination that leaks out to the outside of the safety cabinet can be prevented, and surrounding contamination by microorganisms such as bacteria and viruses and fine dust can be prevented. The safety cabinet is a microorganism that is released from the user because the preparatory operation is automatically performed when the first detection means detects the entry of the user and the second detection means detects the closing of the front opening. And fine dust can be caused to flow into the first duct by the first and second air barriers, and even if microorganisms or fine dust is released from the user by going out or degaunting, the microorganisms or fine dust is filtered. And the work space can be kept clean in the preparatory operation. In the safety cabinet, the idling operation is automatically performed when the first detection means detects the exit of the user and the second detection means detects the closing of the front opening. The first air barrier formed by the supplied air can prevent leakage and diffusion of air from the work space to the outside of the safety cabinet, and the third filter prevents microorganisms such as bacteria and viruses and fine dust. The collected clean air can be constantly supplied to the work space, and the work space can be kept clean.

  The safety cabinet capable of preventing contamination includes a fourth filter for filtering air supplied by the third blower and a fifth filter for filtering air flowing from the first air inlet into the first duct. Even if microorganisms such as bacteria and viruses and fine dust are contained in the air flowing through the second duct, since these microorganisms and dust are collected by the fourth filter, The clean state of the first air barrier formed by the supplied air can be maintained, and the work space can be maintained in a clean state by the first air barrier. In the safety cabinet, even if microorganisms such as bacteria and viruses and fine dust are contained in the air flowing into the first duct from the first air inlet, these microorganisms and dust are collected by the fifth filter. The air flowing into the first and second ducts can be kept in a clean state, and clean air can be supplied to the working chamber and the working space.

  Contamination prevention including side panels located on both lateral sides of the work space, the work space is surrounded by the first and second ducts, the side panel and the floor, and the opposite side of the work chamber is open A possible safety cabinet is defined by a first and second duct, a side panel and a floor, and a predetermined volume of work space is defined by which a user can enter and exit, and the work space is cleaned by the first and second air barriers. Since the opposite side of the working chamber (one end of the working space) is opened, the user can easily enter and exit the working space, and the user can clean the working space. Various tasks can be performed in the environment.

  The second air supply port is a slit extending between the one side panel and the other side panel across the work space, and the air supplied from the third blower passes outside the work space by passing through the slit. The safety cabinet that prevents air contamination that forms an air curtain that blocks the entry of air from the air curtain is safe when air leaks outside the working chamber by the air curtain that forms the second air barrier during use operation. Contamination that leaks out of the cabinet can be prevented, and surrounding contamination by microorganisms such as bacteria and viruses and fine dust can be reliably prevented. In the preparatory operation, the safety cabinet can allow microorganisms and fine dust released from the user to flow into the first duct by the air curtain that forms the second air barrier, and is released from the user by the air curtain. Leakage and diffusion of microorganisms and fine dust to the outside of the safety cabinet can be reliably prevented.

  Contamination in which the air cleanliness level inside the working chamber is grade A, the air cleanliness level in the work space is grade B, and the air cleanliness level outside the work space is grade C or grade D The preventable safety cabinet can keep the air cleanliness level inside the working chamber at grade A and can keep the air cleanliness level of the working space at grade B, so that A room with a cleanliness level of grade B is created, and only one safety cabinet is installed in the room, and a grade C clean room or a clean room with a cleanliness level of grade D around the room of grade B, a buffer Air cleanliness level compared to multiple rooms such as areas and supply rooms In one chamber of the grade C or grade D can be installed a plurality of safety cabinet, it is not necessary to build a large-scale facilities for installation of the safety cabinet.

The side view of the safety cabinet shown as an example. The front view of a safety cabinet. The top view of a safety cabinet. The figure which shows an example of the chamber | room which installed the safety cabinet. The flowchart explaining the transition of each operation mode of a safety cabinet. FIG. 6 is a flowchart of use operation continued from FIG. 5. The side view of the safety cabinet which shows an example of idling driving | operation. The side view of the safety cabinet which shows an example of preparation operation. The side view of the safety cabinet which shows an example of utilization operation. The figure which shows the flow of the air of the safety cabinet of a prior art.

  The details of the safety cabinet capable of preventing contamination according to the present invention will be described with reference to the accompanying drawings such as FIG. 1 which is a side view of the safety cabinet 10 shown as an example. FIG. 2 is a front view of the safety cabinet 10, and FIG. 3 is a top view of the safety cabinet 10. FIG. 4 is a diagram illustrating an example of the chamber 11 in which the safety cabinet 10 is installed. 1 to 3, the vertical direction is indicated by an arrow A (only FIGS. 1 and 2), the front-rear direction is indicated by an arrow B (only FIGS. 1 and 3), and the horizontal direction is indicated by an arrow C (only FIGS. 2 and 3). In FIG. 3, the human sensor 31 and the open / close sensor 32 are not shown.

  As shown in FIG. 4, the safety cabinet 10 capable of preventing contamination is installed in a single chamber 11. In FIG. 4, five safety cabinets 10 are installed in one room 11, but the number of cabinets 10 installed in the room 11 is not limited to that illustrated, and the cabinets 10 installed according to the volume of the room 11. Is determined. Safety cabinet 10 prevents genetic hazards and cell manipulations performed in medicine, pharmaceuticals, etc., or prevents disasters (biohazards) due to contamination of microorganisms such as bacteria and viruses due to research on infectious diseases, etc., or manufacture of precision machinery and semiconductors Used for the purpose of preparing a clean environment.

  The safety cabinet 10 includes a working chamber 12, first to third air flow paths 13 to 15, a working space 16, air circulation first and second ducts 17 and 18, and first and second air inlets. 19, 20; first and second air inlets 21 and 22; first to third blowers 23 to 25; first to fifth filters 26 to 30; and a human sensor 31 (first detecting means). ) And an open / close sensor 32 (second detection means), and a controller 33 (control device).

  The working chamber 12 is a hexahedral box surrounded by a top plate 34, a first bottom plate 35, a front plate 36, a back plate 37, and a side plate 38. The top plate 34, the first bottom plate 35, the back plate 37, and the side plate 38 are rectangular plates made of steel material, stainless steel material, aluminum material, or synthetic resin material. The front plate 36 is a rectangular transparent plate made of a glass material or a synthetic resin material, and a front shutter 39 that can be opened and closed is attached to the lower portion thereof. The working chamber 12 includes a germicidal lamp (not shown) that irradiates ultraviolet rays to the lower portion of the top plate 34.

  The front shutter 39 is a transparent plate made of glass or synthetic resin, and is installed on the front plate 36 so as to be slidable in the vertical direction. When the front shutter 39 is lifted, a front opening 40 (see FIG. 9) is created in the working chamber 12 to open a part (lower part) of the front surface of the chamber 12, and when the raised shutter 39 is pulled down, the front opening 40 is opened. It is closed and the front is closed. A user 52 to be described later inserts a hand or an arm into the chamber 12 through the front opening 40 of the working chamber 12 and performs a predetermined work in the chamber 12. An air inflow opening 41 is formed in the vicinity of the front opening 40 at the bottom of the working chamber 12 (first bottom plate 35). The air inflow opening 41 extends between one side plate 38 and the other side plate 38 of the working chamber 12 and crosses the chamber 12.

  The first air flow path 13 is positioned below (directly below) the working chamber 12 and extends in the front-rear direction. The first air flow path 13 is defined between a first bottom surface plate 35 of the chamber 12 and a second bottom surface plate 42 that is spaced downward from the first bottom surface plate 35 and extends in the front-rear direction. The first air flow path 13 is connected to an air inflow opening 41 formed at the bottom of the working chamber 12, and the air flowing in from the air inflow opening 41 flows therethrough.

  The second air flow path 14 is located behind (immediately after) the working chamber 12 and extends in the vertical direction. The second air flow path 14 is defined between the back plate 37 of the chamber 12 and the air circulation first duct 17 that is spaced rearward from the back plate 37. The second air flow path 14 is connected to the first air flow path 13, and the air flowing in from the first air flow path 13 flows therethrough.

  The third air flow path 15 is located above (directly above) the working chamber 12 and extends in the front-rear direction. The third air flow path 15 is defined between the top plate 34 of the chamber 12 and the air circulation second duct 18 spaced upward from the top plate 34. The third air flow path 15 is connected to the second air flow path 14, and the air flowing in from the second air flow path 14 flows therethrough.

  The work space 16 includes an air circulation first duct 17 (including a back panel 43 extending in the vertical direction), an air circulation second duct 18 (including the top panel 44 extending in the front-rear direction), and a side panel 45 extending in the vertical direction. It is surrounded by the floor surface 46 and has a predetermined volume that allows the user 52 to enter and exit and allows the user 52 to work. A chair 47 on which the user 52 sits is installed immediately before the working chamber 12 in the working space 16.

  The back panel 43, the top panel 44, and the side panel 45 are rectangular plates made of steel, stainless steel, aluminum, or synthetic resin. The rear panel 43, the top panel 44, and the side panel 45 are hermetically fixed to the floor 46 at the lower edges. The working space 16 is defined in front of the working chamber 12, and the opposite side of the chamber 12 (the front end of the space 16) is opened to form an entrance / exit 48. A user 52 who uses the working chamber 12 enters the space 16 from an entrance 48 (front end) of the working space 16.

  The air circulation first duct 17 is positioned behind (immediately after) the second air flow path 14 and extends in the vertical direction. The air circulation first duct 17 extends from the vicinity of the floor surface 46 to the upper side of the third air flow path 15 in parallel with the second air flow path 14. Air flowing from the vicinity of the floor surface 46 (first air inlet 19) flows through the air circulation first duct 17. The second air circulation duct 18 is connected to the first air circulation duct 17 and is located above (directly above) the third air flow path 15 and extends in the front-rear direction. The air circulation second duct 18 extends in parallel with the third air flow path 15 immediately before the second air flow path 14 and above the work space 16 and extends to the entrance 48 (front end) of the space 16. The air flowing from the air circulation first duct 17 flows through the air circulation second duct 18.

  The first air inlet 19 is installed at the bottom of the air circulation first duct 17 extending in the vicinity of the floor surface 46 (extending below the first air flow path 13). The air in the work space 16 flows through the first air inlet 19, and the air flows into the bottom of the air circulation first duct 17 through the first air inlet 19. The second air inlet 20 is installed at the lower part of the air circulation second duct 18 extending above the third air flow path 15. The air flowing through the third air flow path 15 flows through the second air inlet 20, and the air flows into the air circulation second duct 18 through the second air inlet 20.

  The first air supply port 21 is installed in the air circulation second duct 18 extending to the rear area 49 and the central area 50 of the work space 16, and air is directed to the floor area 46 of the rear area 49 and the central area 50 of the space 16. To supply air. The second air supply port 22 is located in front of the first air supply port 21, and is installed in the air circulation second duct 18 that extends to the front area 51 of the work space 16. The second air supply port 22 is a slit that extends between the one side panel 45 and the other side panel 45 across the work space 16. The second air supply port 22 supplies air toward the floor surface 46 of the front area 51 of the work space 16.

  The first blower 23 is installed in the third air flow path 15 located on the second air flow path 14 side, and the air that has flowed into the third air flow path 15 is moved downward from the top (top) of the working chamber 12 ( The air flowing into the third air flow path 15 is caused to flow from the second air inlet 20 into the air circulation second duct 18. The control unit of the first blower 23 is connected to the controller 33 by a signal line or wirelessly.

  The second blower 24 is an air circulation second duct 18 that extends in the rear area 49 and the central area 50 of the work space 16 and above the space 16 (a second air that extends directly above the user 52 who is using the work chamber 12. It is installed in the duct 18). The second blower 24 supplies air that has flowed into the second air circulation duct 18 from the upper side of the work space 16 toward the lower side (floor surface 46) via the first air supply port 21.

  The air supplied from the second blower 24 is directed to the user 52 from directly above the user 52 who is using the working chamber 12, and is directed to the rear area 49 of the work space 16 and the floor surface 46 of the central area 50. To flow. The control unit of the second blower 24 is connected to the controller 33 by a signal line or wirelessly.

  The third blower 25 is an air circulation second duct 18 (second duct 18 extending in front of the user 52 using the working chamber 12) that is the front area 51 of the work space 16 and extends above the space 16. is set up. The third blower 25 supplies the air that has flowed into the second air circulation duct 18 from the upper side of the work space 16 toward the lower side (floor surface 46) via the second air supply port 22 (slit).

  The air supplied from the third blower 25 forms an air curtain that blocks the entry of air from outside the work space 16 (inside the chamber 11) by passing through the slit (second air supply port 22). Then, it flows toward the floor surface 46 of the front area 51 of the space 16. The control unit of the third blower 25 is connected to the controller 33 by a signal line or wirelessly.

  The first filter 26 is installed on the top (top plate 34) of the working chamber 16. The first filter 26 is housed in a filter case (not shown), and is detachably attached to the top plate 34 of the working chamber 16 via the case. The first filter 26 filters the air flowing into the working chamber 16 from the third air flow path 15 and captures microorganisms such as bacteria and viruses and fine dust contained in the air flowing through the third air flow path 15. Collect and send clean air to work space 16.

  The second filter 27 is installed directly above the second air inflow port 20 above the third air flow path 15. The second filter 27 is housed in a filter case (not shown), and is detachably attached to the upper part of the third air flow path 15 via the case. The second filter 27 filters air flowing from the third air flow path 15 into the air circulation second duct 18, and microorganisms such as bacteria and viruses contained in the air flowing through the third air flow path 15 and fine dust. And clean air is sent to the second duct 18.

  The third filter 28 is installed in the first air supply port 21 and is disposed in the rear area 49 and the central area 50 of the work space 16. The third filter 28 is housed in a filter case (not shown), and is detachably attached to the first air supply port 21 via the case. The third filter 28 filters air supplied from the air circulation second duct 18 toward the rear area 49 and the central area 50 of the work space 16, and bacteria, viruses, etc. contained in the air flowing through the second duct 18. The microbes and fine dust are collected, and clean air is sent to the rear area 49 and the central area 50 of the space 16.

  The fourth filter 29 is installed in the second air supply port 22 and is disposed in the front area 51 of the work space 16. The fourth filter 29 is housed in a filter case (not shown), and is detachably attached to the second air supply port 22 via the case. The fourth filter 29 filters air supplied from the air circulation second duct 18 toward the front area 51 of the work space 16, and microorganisms such as bacteria and viruses contained in the air flowing through the second duct 18 and fine particles. Fresh dust is collected and clean air is sent to the front area 51 of the space 16.

  The fifth filter 30 is installed at the first air inlet 19 and is disposed at the bottom of the air circulation first duct 17. The fifth filter 30 is housed in a filter case (not shown), and is detachably attached to the first air inlet 19 via the case. The fifth filter 30 filters the air supplied to the work space 16 from the first and second air supply ports 21, 22, and microbes such as bacteria and viruses contained in the air flowing through the space 16 and fine Dust is collected and clean air is sent to the air circulation first duct 17.

  HEPA filters are used for the first to fifth filters 26 to 30. The filters 26 to 30 are replaced with new ones after being used for a predetermined period. In addition, the dust collection efficiency of the 1st-5th filters 26-30 is 99.97% or more in 0.3 micrometer particle | grains. ULPA filters can also be used for the first to fifth filters 26 to 30. The fifth filter 30 may be a medium performance filter or a pre-filter that reduces the burden on the first to fourth filters 26 to 29 located downstream thereof.

  The human sensor 31 (first detection means) is installed on the upper portion of the front plate 36 of the working chamber 16. The human sensor 31 is connected to the controller 33 by a signal line or wirelessly. It should be noted that the installation location of the human sensor 31 is appropriately determined in consideration of the sensing range of the sensor 31 and may be installed other than the upper portion of the front plate 36.

  When the user 52 enters the work space 16, the human sensor 31 transmits an entry signal to the controller 33, and when the user 52 does not exist in the space 16, or the user 52 who has entered the space 16 has the space. If the user exits 16, the exit signal is transmitted to the controller 33. The human sensor 31 irradiates the work space 16 with invisible light and detects the human body by reflection of the invisible light, and irradiates the work space 16 with microwave and reflects the microwave to the human body. A microwave Doppler sensor that detects the human body and an ultrasonic sensor that irradiates the work space 16 with ultrasonic waves and detects the human body by reflection of the ultrasonic waves can be used.

  When the human sensor is installed on the chair 47 and the user 52 sits on the chair 47, an approach signal is transmitted to the controller 33, and when the user 52 leaves the chair 47, an exit signal is transmitted to the controller 33. To do. A pressure sensor can be used for the human sensor installed in the chair 47.

  The open / close sensor 32 (second detection means) is installed on the front plate 36 or the front shutter 39 of the working chamber 16. The open / close sensor 32 is connected to the controller 33 by a signal line or wirelessly. When the front shutter 39 is pulled up and a part of the front surface of the working chamber 16 (front opening 40) is opened, the open / close sensor 32 transmits an open signal to the controller 33, and the front surface of the chamber 16 (front opening 40). Is closed, or when the shutter 39 is pulled down to close the front surface of the chamber 16 (front opening 40), a closing signal is sent to the controller 33. As the open / close sensor 32, a limit switch, a pressure sensitive switch, a photoelectric switch, or a proximity sensor can be used.

  The controller 33 is a computer having a central processing unit (CPU or MPU) and memory (main memory and cache memory), and has a built-in storage device. Input / output devices such as a numeric keypad unit (not shown), a touch panel (not shown), and a display (not shown) are connected to the controller 33 via an interface. The central processing unit of the controller 33 activates an application from the memory based on control by the operating system, and performs an idling operation, a preparation operation, and a utilization operation described later according to the activated application.

  The storage device of the controller 33 includes the start and stop of the first to third fans 23 to 25 in the idling operation, the preparation operation, and the use operation, the wind speed of the first to third fans 23 to 25 in the idling operation and the preparation operation, and the use operation. The setting information of the air volume of the first to third blowers 23 to 25 in the idling operation, the preparation operation, and the use operation is stored. The wind speed and air volume of the first to third blowers 23 to 25 in various operations can be arbitrarily set by an input device such as a numeric keypad unit or a touch panel.

  In the safety cabinet 10, when the presence sensor 31 detects the absence of the user 52 with respect to the work space 16 and the open / close sensor 32 detects the closing of the front opening 40 of the working chamber 12 by the front shutter 39, the idling operation is performed. When the presence sensor 31 detects the presence of the user 52 in the space 16 and the opening / closing sensor 32 detects the closing of the front opening 40 of the chamber 12 by the shutter 39, the preparatory operation is performed. When the presence sensor 31 detects the presence of the user 52 in the work space 16 and the open / close sensor 32 detects the opening of the front opening 40 of the work chamber 12, the use operation is performed.

  Although not shown, an idling operation button, a preparation operation button, and a use operation button are displayed on the touch panel connected to the controller 33, and the user 52 who has entered the work space 16 of the safety cabinet 10 selects the preparation operation button. It is also possible to start the preparatory operation by pressing and perform gouning (wearing protective clothing and dust-free clothing), and press the use operation button immediately before pulling up the front shutter 39 to switch from the preparation operation to the use operation. In this case, after the user 52 who has finished the work pulls down the shutter 39 and closes the front opening 40, the preparatory operation button is pressed to switch from the use operation to the preparatory operation, and degauning is performed. Just before starting, press the idling operation button to switch from the preparation operation to the idling operation.

  FIG. 5 is a flowchart for explaining the transition of each operation mode of the safety cabinet 10, and FIG. 6 is a flowchart continued from FIG. FIG. 7 is a side view of the safety cabinet 10 showing an example of idling operation, and FIG. 8 is a side view of the safety cabinet 10 showing an example of preparation operation. FIG. 9 is a side view of the safety cabinet 10 showing the use operation.

  When the safety cabinet 10 is activated, an idling operation is first performed (S-10). In the idling operation, the controller 33 transmits an activation signal to the control units of the first and second blowers 23 and 24 and transmits a wind speed signal to the control units of the blowers 23 and 24. The controller 33 transmits an activation signal to the human sensor 31 and the open / close sensor 32. In the idling operation, the third blower 25 is not started and the stopped state of the third blower 25 is maintained.

  The control unit of the first blower 23 starts the first blower 23 with an output corresponding to the wind speed signal and maintains the output of the first blower 23 in accordance with the start signal and the wind speed signal transmitted from the controller 33. The control unit of the second blower 24 starts the second blower 24 with an output corresponding to the wind speed signal and maintains the output of the second blower 24 in accordance with the start signal and the wind speed signal transmitted from the controller 33.

  In idling operation, the human sensor 31 monitors the entry and exit of the user 52 from the work space 16, and the open / close sensor 32 monitors the open and closed states of the front opening 40. In the idling operation, the wind speed of the air supplied from the second blower 24 is slower than the wind speed of the air supplied from the second blower 24 in the use operation and the preparation operation described later.

  In the idling operation, as indicated by an arrow in FIG. 7, the first blower 23 is operated so that the air is working chamber 12 → first air flow path 13 → second air flow path 14 → third air flow path 15. The air is circulated in the order of the air circulation first duct 17 → the air circulation second duct 18 → the work space 16 by the second air blower 24 being operated. In the idling operation, air is not supplied from the third blower 25. The wind speed of air supplied from the second blower 24 (first air supply port 21) in the idling operation is, for example, in the range of 0.1 to 0.2 m / s, and preferably 0.15 m / s. The air volume of the air supplied from the second blower 24 (first air supply port 21) is, for example, in the range of 300 to 600 m3 / h, preferably 450 m3 / h.

  In the idling operation, the air passed through the first filter 26 by the first blower 23 is caused to flow from the upper side (top) to the lower side (bottom) of the working chamber 12 and the air is directly below the front shutter 39 ( While flowing into the first air passage 13 from the air inflow opening 41 formed in the vicinity of the front opening 40), the air is again introduced into the third air passage 15 from the second air passage 14. To flow into. The air flowing into the working chamber 12 from the third air flow path 15 flows through the first filter 26, so that microorganisms such as bacteria and viruses and fine dust contained therein are collected in the filter 26 and cleaned. Air is supplied to the working chamber 12.

  In the idling operation, the air flowing through the second air circulation duct 18 is passed through the third filter 28 by the second blower 24, and the rear area 49 and the central area 50 of the work space 16 from the first air supply port 21. The air is supplied from above to below toward the floor surface 46. The air flowing through the first air circulation duct 17 and the second air circulation duct 18 flows through the third filter 28, so that microorganisms such as bacteria and viruses and fine dust contained therein are collected by the filter 28. Then, the air becomes clean air and is supplied toward the floor surface 46 of the work space 16.

  The air from the first air supply port 21 toward the floor surface 46 passes through the fifth filter 30 from the first air inlet 19 through the lower part of the working chamber 12, and then enters the air circulation first duct 17. It flows into the air circulation second duct 18 from the first duct 17. The air flowing into the second duct 18 from the first duct 17 is supplied again from the first air supply port 21 toward the floor surface 46 by the second blower 24. The air flowing through the work space 16 flows through the fifth filter 30, so that microorganisms such as bacteria and viruses and fine dust contained therein are collected by the filter 30 and become clean air to form the first duct. 17 flows in.

  While continuing the idling operation, the controller 33 determines whether the human sensor 31 has detected the entry of the user 52 into the work space 16 (S-11). When the user 52 does not enter the work space 16 and the user 52 does not exist in the space 16, the human sensor 31 transmits an exit signal of the user 52 to the controller 33. When the entry of the user 52 to the work space 16 is not detected and the exit of the user 52 is detected, the controller 33 continues the idling operation (S-12). In the idling operation, the first blower 23 may be stopped and only the second blower 24 may be operated. In this case, air is not supplied to the working chamber 12, and the air circulates in the order of the air circulation first duct 17 → the air circulation second duct 18 → the work space 16.

  In the idling operation, the safety cabinet 10 capable of preventing contamination is air in the rear area 49 and the central area 50 of the work space 16 from the first air supply port 21 through the air that has been passed through the third filter 28 by the second blower 24. By supplying air from the space 16 to the first and second ducts 17 and 18 while supplying air toward the floor surface 46, the air supplied from the first air supply port 21 becomes the first air barrier. Therefore, air leakage and diffusion from the space 16 to the chamber 11 (outside the safety cabinet 10) can be prevented. The safety cabinet 10 can always supply clean air in which microbes such as bacteria and viruses and fine dust are collected by the third filter 28 to the space 16, and the space 16 is kept clean in idling operation. Can be adjusted and maintained.

  The safety cabinet 10 can always flow clean air in which microorganisms such as bacteria and viruses are filtered by the first filter 26 into the working chamber 12 while the working chamber 16 is not used in idling operation. 12 can be adjusted and maintained in a clean state. Since the interior of the working chamber 12 is kept clean during idling operation, the safety cabinet 10 can keep the chamber 12 in a usable state at all times, and the user 52 uses the chamber 12 immediately. be able to.

  The safety cabinet 10 reduces the wind speed of the air supplied from the second blower 24 in the idling operation to be slower than the wind speed of the air supplied from the second blower 24 in the use operation and the preparation operation. Since a smaller amount of air can be supplied to the work space 16 than in the preparation operation, energy consumption can be reduced in idling operation without using the safety cabinet 10, and energy saving can be realized. .

  When the user 52 enters the space 16 from the entrance 48 of the work space 16 and the user 52 exists in the space 16, the human sensor 31 transmits an entry signal of the user 52 to the controller 33. The controller 33 that has received the entry signal from the human sensor 31 determines that the user 52 has entered the work space 16 in step 11 (S-11), interrupts the idling operation, and performs the preparation operation (S). -13).

  In the preparatory operation, the controller 33 transmits a wind speed signal to the control unit of the second blower 24, transmits an activation signal to the control unit of the third blower 25, and transmits a wind speed signal to the control unit of the third blower 25. The controller of the first blower 23 maintains the output of the first blower 23 as in the idling operation.

  The control unit of the second blower 24 changes the output corresponding to the wind speed signal according to the wind speed signal transmitted from the controller 33, and maintains the changed output of the second blower 24. The control unit of the third blower 25 starts the third blower 25 with an output corresponding to the wind speed signal and maintains the output of the third blower 25 according to the start signal and the wind speed signal transmitted from the controller 33.

  In the preparation operation, the human sensor 31 monitors the exit of the user 52 from the work space 16, and the open / close sensor 32 monitors the opening of the front opening 40. In the preparatory operation, the flow rate of the air supplied from the second blower 24 is larger than the flow rate of the air supplied from the third blower 25, and the wind speed of the air supplied from the third blower 25 is the second blower. It is faster than the wind speed of the air supplied from 24. Further, in the preparation operation, the wind speed of the air supplied from the second blower 24 is faster than the wind speed of the air supplied from the second blower 24 in the use operation.

  In the preparatory operation, as indicated by an arrow in FIG. 8, the first blower 23 is operated, so that the air is working chamber 12 → the first air flow path 13 → the second air flow path 14 → the third air flow path 15. The air circulates in the order of the air circulation first duct 17 → the air circulation second duct 18 → the work space 16 by the second and third blowers 24 operating. The user 52 that has entered the work space 16 prepares for a bow or various operations in the preparation operation.

  The wind speed of the air supplied from the second blower 24 (first air supply port 21) in the preparation operation is, for example, in the range of 0.3 to 0.60 m / s, and preferably 0.45 m / s. The air volume of the air supplied from the second blower 24 (first air supply port 21) is, for example, in the range of 900 to 1500 m3 / h, preferably 1350 m3 / h. The wind speed of the air supplied from the third blower 25 (second air supply port 22) in the preparation operation is, for example, in the range of 1.50 to 1.90 m / s, preferably 1.70 m / s. The air volume of the air supplied from the third blower 25 (second air supply port 22) is, for example, in the range of 400 to 600 m3 / h, preferably 500 m3 / h.

  In the preparatory operation, the air that has been passed through the first filter 26 by the first blower 23 flows from the upper side to the lower side of the working chamber 12, and the air is formed in the air inflow opening formed directly below the front shutter 39. While flowing from 41 to the first air flow path 13, flow from the second air flow path 14 to the third air flow path 15 and flow the air into the working chamber 12 again.

  In the preparatory operation, the air flowing through the second air circulation duct 18 is passed through the third filter 28 by the second blower 24, and the rear area 49 and the central area 50 of the work space 16 from the first air supply port 21. While supplying air toward the floor surface 46 and allowing the air flowing through the second duct 18 to flow through the fourth filter 29 by the third blower 25, the front area 51 of the work space 16 from the second air supply port 22. The air is supplied toward the floor surface 46.

  The air supplied from the second air supply port 22 (slit) by the third blower 25 is the front area of the work space 16 in front of the air supplied from the first air supply port 21 by the second blower 24. An air curtain crossing 51 is formed. The air flowing through the air circulation first duct 17 and the air circulation second duct 18 flows through the fourth filter 29, so that microorganisms such as bacteria and viruses and fine dust contained therein are captured by the filter 29. The air is collected, becomes clean air, and is supplied from the second air supply port 22 toward the floor surface 46 of the work space 16. In the preparatory operation, even if the air in the chamber 11 is about to enter the work space 16, as shown by an arrow L2 in FIG. 8, an air curtain formed by the air supplied from the second air supply port 22 (slit). Is prevented from entering the work space 16.

  The air from the first and second air supply ports 21 and 22 toward the floor surface 46 passes through the lower part of the working chamber 12, passes through the fifth filter 30 from the first air inlet 19, and then circulates air. It flows into the first duct 17 and flows from the first duct 17 into the air circulation second duct 18. The air flowing into the second duct 18 from the first duct 17 is supplied again from the first and second air supply ports 21 and 22 toward the floor surface 46 by the second and third blowers 24 and 25.

  In the preparatory operation, the air supplied from the first air supply port 21 enters the first air inlet 19 from the rear of the air curtain formed by the air supplied from the second air supply port 22 (slit). The air that flows in and is supplied from the second air supply port 22 flows into the first air inlet 19 from the front of the air supplied from the first air supply port 21. Therefore, even if the air supplied from the first air supply port 21 is about to flow out of the work space 16 into the chamber 11 (even if the air in the chamber 11 is about to flow into the work space 16), the second air supply port 22 is used. The air curtain formed by the air supplied from the air prevents the air from flowing into the chamber 11, and the air in the chamber 11 enters the front plate 36 and the front shutter 39 of the working chamber 12 in the work space 16. Is also prevented.

  While continuing the preparation operation, the controller 33 determines whether the opening / closing sensor 32 detects the opening of the front opening 40 of the working chamber 12 (S-14). When the front shutter 39 is not lifted and the opening of the front opening 40 is not detected, the open / close sensor 32 transmits a closing signal for the front opening 40 to the controller 33. The controller 33 that has received the closing signal from the opening / closing sensor 32 determines whether or not the human sensor 31 has detected that the user 52 has left the work space 16 (S-15).

  In step 15 (S-15), when the exit of the user 52 is not detected and the approach signal is transmitted from the human sensor 31, the controller 33 continues the preparatory operation (S-16). . In the preparation operation, the first blower 23 may be stopped and only the second blower 24 may be operated. In this case, air is not supplied to the working chamber 12, and the air circulates in the order of the air circulation first duct 17 → the air circulation second duct 18 → the work space 16.

  In step 15 (S-15), when the exit of the user 52 is detected and the exit signal is transmitted from the human sensor 31, the controller 33 interrupts the preparation operation and performs the idling operation shown in FIG. 7 again. (S-10). When the idling operation is performed again, the controller 33 transmits a stop signal to the control unit of the third blower 25 and transmits a wind speed signal to the control unit of the second blower 24. The control unit of the third blower 25 stops the third blower 25 according to the stop signal transmitted from the controller 33. The control unit of the second blower 24 changes to the output corresponding to the wind speed signal according to the wind speed signal transmitted from the controller 33, and maintains the changed output.

  In the safety cabinet 10 capable of preventing contamination, the air that has been passed through the third filter 28 by the second blower 24 in the preparation operation from the first air supply port 21 in the rear area 49 and the central area 50 of the work space 16. By supplying air from the space 16 to the air circulation first and second ducts 17 and 18 while supplying air toward the floor surface 46, the air supplied from the first air supply port 21 is changed to the first air supply port 21. While forming an air barrier and supplying air that has been passed through the fourth filter 29 by the third blower 25 from the second air supply port 22 toward the floor surface 46 of the front area 51 of the work space 16, By flowing air from the space 16 into the first and second ducts 17 and 18, the air supplied from the second air supply port 22 forms a second air barrier. Even if the user 52 exists in the work space 16, microorganisms such as bacteria and viruses and fine dust released from the user 52 are transferred to the first and second ducts 17 and 18 by the first and second air barriers. It is possible to flow in, and leakage and diffusion of microorganisms and dust into the chamber 11 can be prevented.

  The safety cabinet 10 supplies the air that has been passed through the third to fifth filters 28 to 30 by the second and third blowers 24 and 25 toward the floor surface 46 of the work space 16. The clean air in which microorganisms and dust discharged from the user 52 are collected by the five filters 28 to 30 can be constantly supplied to the work space 16, and the space 16 can be kept clean in the preparation operation. it can.

  The safety cabinet 10 can always flow clean air in which microorganisms such as bacteria and viruses are filtered by the first filter 26 into the working chamber 12 while the working chamber 16 is not used in the preparation operation. 12 can be kept clean. In the safety cabinet 10, since the inside of the working chamber 12 is maintained in a clean state in the preparation operation, the chamber 12 can be always used, and the user 52 uses the chamber 12 immediately. be able to.

  The safety cabinet 10 is supplied from the second air supply port 22 by making the wind speed of the air supplied from the third blower 25 faster than the speed of the air supplied from the second blower 24 in the preparation operation. It is possible to improve the barrier function of the second air barrier (air curtain) formed from the fresh air, and the air supplied from the first air supply port 21 is the air supplied from the third blower 25 ( Even if the user 52 exists in the work space 16, microorganisms such as bacteria and viruses and fine dust that are released from the user 52 are not leaked outside the second air barrier). The barrier can surely flow into the first and second ducts 17 and 18. In addition, by making the wind speed of the air supplied from the first air supply port 21 slower than that of the air supplied from the second air supply port 22, Discomfort can be reduced.

  In the preparatory operation, the safety cabinet 10 makes the air supplied from the second blower 24 faster at the time of the preparatory operation than at the time of the use operation, so that the air supplied from the first air supply port 21 is increased. The barrier function of the first air barrier formed from the above can be improved as compared with the use operation, the user 52 exists in the work space 16, and the user 52 performs gouning and de-gouning in the work space 16. Therefore, even if microorganisms such as bacteria and viruses and fine dust are released from the user 52, the microorganisms and fine dust can be surely flowed into the first and second ducts 17 and 18 by the first air barrier. it can.

  The safety cabinet 10 increases the flow rate of air supplied from the second blower 24 (first air supply port 21) more than the flow rate of air supplied from the third blower 25 (second air supply port 22). Thus, since a large amount of air passed through the third filter 28 by the second blower 24 can be supplied toward the floor surface 46 of the work space 16, microorganisms such as bacteria and viruses can be supplied by the third filter 28. In addition, clean air in which fine dust is collected can be constantly supplied to the work space 16, and the work space 16 can be kept clean in the preparation operation.

  When the user 52 who has entered the work space 16 pulls up the front shutter 39 and opens the front opening 40 of the work chamber 12 during the preparatory operation, the open / close sensor 32 transmits an open signal to the controller 33. In step 14 (S-14), the controller 33 that has received the opening signal from the open / close sensor 32 determines that the front opening 40 of the working chamber 12 has been opened, interrupts the preparation operation, and performs the use operation (S). -17).

  In the use operation, the controller 33 transmits a wind speed signal to the control units of the second and third blowers 24 and 25. The control part of the 1st air blower 23 maintains the output of the 1st air blower 23 similarly to the idling operation and the preparation operation. The control units of the second and third blowers 24 and 25 change the output corresponding to the wind speed signal according to the wind speed signal transmitted from the controller 33, and maintain the changed output.

  In use driving, the human sensor 31 monitors the exit of the user 52 from the work space 16, and the open / close sensor 32 monitors the closing of the front opening 40. In the use operation, the flow rate of the air supplied from the second blower 24 is larger than the flow rate of the air supplied from the third blower 25, and the wind speed of the air supplied from the third blower 25 is the second blower. It is faster than the wind speed of the air supplied from 24.

  In the use operation, as indicated by an arrow in FIG. 9, the first blower 23 is operated, so that the air is working chamber 12 → the first air flow path 13 → the second air flow path 14 → the third air flow path 15. The air circulates in the order of the air circulation first duct 17 → the air circulation second duct 18 → the work space 16 by the second and third blowers 24 operating. Further, the air circulates in the order of the first air flow path 13 → the second air flow path 14 → the third air flow path 15 → the air circulation second duct 18 → the work space 16. In the use operation, the user 52 inserts hands and arms into the chamber 12 through the front opening 40 of the working chamber 12 and performs various operations inside the chamber 12.

  The wind speed of the air supplied from the second blower 24 (first air supply port 21) in the use operation is, for example, in the range of 0.25 to 0.35 m / s, preferably 0.30 m / s. The air volume of the air supplied from the second blower 24 (first air supply port 21) is, for example, in the range of 870 to 930 m3 / h, preferably 900 m3 / h. The wind speed of the air supplied from the third blower 25 in the use operation is, for example, in the range of 1.50 to 1.90 m / s, preferably 1.70 m / s, and is supplied from the third blower 25. The air volume of the air is, for example, in the range of 470 to 530 m <3> / h, preferably 500 m <3> / h.

  In the use operation, the air passed through the first filter 26 by the first blower 23 flows from the upper side to the lower side of the working chamber 12, and the air is formed in the air inflow opening formed directly below the front shutter 39. While flowing from 41 to the first air flow path 13, the second air flow path 14 flows into the third air flow path 15, and a part of the air flows into the working chamber 12 again. Further, the remaining portion of the air is passed through the second filter 27 and flows into the air circulation second duct 18 from the second air inlet 20.

  In the use operation, air flowing through the second air circulation duct 18 is passed through the third filter 28 by the second blower 24, and the rear area 49 and the central area 50 of the work space 16 from the first air supply port 21. While supplying air toward the floor surface 46 and allowing the air flowing through the second duct 18 to flow through the fourth filter 29 by the third blower 25, the front area 51 of the work space 16 from the second air supply port 22. The air is supplied toward the floor surface 46.

  The air supplied from the second air supply port 22 (slit) by the third blower 25 is the front area of the work space 16 in front of the air supplied from the first air supply port 21 by the second blower 24. An air curtain crossing 51 is formed. The air flowing through the air circulation first duct 17 and the air circulation second duct 18 flows through the fourth filter 29, so that microorganisms such as bacteria and viruses and fine dust contained therein are captured by the filter 29. The air is collected, becomes clean air, and is supplied from the second air supply port 22 toward the floor surface 46 of the work space 16. In the use operation, even if the air in the chamber 11 tries to enter the work space 16, as shown by an arrow L2 in FIG. 9, an air curtain formed by the air supplied from the second air supply port 22 (slit). Is prevented from entering the work space 16.

  The air from the first and second air supply ports 21 and 22 toward the floor surface 46 passes through the lower part of the working chamber 12, passes through the fifth filter 30 from the first air inlet 19, and then circulates air. It flows into the first duct 17 and flows from the first duct 17 into the air circulation second duct 18. In the use operation, the air flowing into the second duct 18 from the first duct 17 and the air flowing into the second duct 18 from the second air inlet 20 through the third air flow path 15 are mixed into an air-fuel mixture. Then, the air-fuel mixture is supplied again from the first and second air supply ports 21 and 22 toward the floor 46 by the second and third blowers 24 and 25.

  In the use operation, the air (air mixture) supplied from the first air supply port 21 is behind the air curtain formed by the air (air mixture) supplied from the second air supply port 22 (slit). From the front of the air supplied from the first air inlet 21, the air supplied from the second air inlet 22 flows into the first air inlet 19. . Therefore, even if the air supplied from the first air supply port 21 tries to flow into the chamber 11 from the work space 16, the chamber 11 is formed by the air curtain formed by the air supplied from the second air supply port 22. Entry into is blocked.

  In the use operation, a part of the air supplied from the first air supply port 21 flows into the first air flow path 13 from the front opening 40 through the air inflow opening 41, and the second and third air flow paths. 14 and 15 flows into the working chamber 12 and the second duct. In the use operation, the airflow in the vicinity of the front opening 40 is disturbed by the movement of the user 52 or the arm of the user 52 inserted into the working chamber 12 from the front opening 40, whereby a part of the air flowing through the chamber 12 is opened to the front opening There is a case in which leakage occurs from the work space 16 to the work space 16 (outside the chamber 12).

  However, in the safety cabinet 10, the air inside the working chamber 12 leaked from the front opening 40 to the work space 16 joins the air supplied from the first air supply port 21 as indicated by an arrow L3 in FIG. Then, the fifth filter 30 flows through the first air inlet 19 from below the chamber 12, and the third and fourth filters 28, 29 flow through the first and second ducts 17, 18. . Therefore, microorganisms such as bacteria and viruses contained in the air inside the working chamber 12 are collected by the filters 28 to 30 and become clean air from the first and second air supply ports 21 and 22. The air is supplied toward the 16 floor surfaces 46.

  While continuing the use operation, the controller 33 determines whether or not the opening / closing sensor 32 detects the closing of the front opening 40 of the working chamber 12 (S-18). When the front shutter 39 is not lowered and the closing of the front opening 40 is not detected, the open / close sensor 32 transmits an opening signal of the front opening 40 to the controller 33. While receiving the open signal from the open / close sensor 32, the controller 33 determines that the front opening 40 is open in step 18 (S-18), and continues the use operation (S-19). .

  In step 18 (S-18), when the user 52 pulls down the front shutter 39 and the front opening 40 is closed by the shutter 39, the open / close sensor 32 transmits a closing signal of the front opening 40 to the controller 33. The controller 33 that has received the closing signal from the open / close sensor 32 determines that the front opening 40 is closed in step 18 (S-18).

  Next, the controller 33 determines whether or not the exit of the user 52 with respect to the work space 16 is detected by the human sensor 31 (S-20). When the exit of the user 52 is not detected and the approach signal is transmitted from the human sensor 31, the controller 33 determines in step 20 (S-20) that the user 52 exists in the work space 16, and uses the The operation is interrupted and the preparatory operation shown in FIG. 8 is performed again (S-13).

  In the preparatory operation in this case, the user 52 performs degaunting and tidying work. When the preparation operation is performed again, the controller 33 transmits a wind speed signal to the control units of the second and third blowers 24 and 25. The control units of the second and third blowers 24 and 25 change the output corresponding to the wind speed signal according to the wind speed signal transmitted from the controller 33, and maintain the changed output.

  When the user 52 who has performed degaunting or tidying work exits the space 16 through the entrance 48 of the work space 16, the human sensor 31 transmits an exit signal to the controller 33. When the controller 33 receives the exit signal from the human sensor 31, it determines that the user 52 does not exist in the work space 16 in step 20 (S-20).

  Next, the controller 33 determines whether or not the stop of the operation of the safety cabinet 10 has been commanded (S-21). When the stop is not instructed, the controller 33 performs the idling operation shown in FIG. 7 again (S-10). In addition, when a stop is instruct | indicated, the controller 33 stops the driving | operation of the safety cabinet 10, and the 1st-3rd air blowers 23-25, the human sensitive sensor 31, and the opening / closing sensor 32 stop.

  In the safety cabinet 10, the cleanliness level of the air inside the working chamber 12 during idling operation, preparation operation, and use operation is defined as EU-GMP (EU Guidelines to Good Manufacturing Practice Medical Products for Human and Veterinary Use). Grade A (equivalent to 5 of ISO-146411-1) is maintained, and the air cleanliness level of the work space 16 is maintained at grade B (equivalent to ISO 7). The cleanliness level of the air outside the work space 16 (chamber 11) is grade C (equivalent to ISO 8) or grade D (equivalent to ISO 8).

  In the use operation, the safety cabinet 10 capable of preventing contamination is air in the rear area 49 and the central area 50 of the work space 16 from the first air supply port 21 through the air that has been passed through the third filter 28 by the second blower 24. By supplying air from the space 16 to the air circulation first and second ducts 17 and 18 while supplying air toward the floor surface 46, the air supplied from the first air supply port 21 is changed to the first air supply port 21. While forming an air barrier and supplying air that has been passed through the fourth filter 29 by the third blower 25 from the second air supply port 22 toward the floor surface 46 of the front area 51 of the work space 16, By flowing air from the space 16 into the first and second ducts 17 and 18, the air supplied from the second air supply port 22 forms a second air barrier. The movement of the hand or arm of the user 52 inserted into the working chamber 12 from the front opening 40 disturbs the airflow in the vicinity of the front opening 40, and a part of the air flowing through the chamber 12 is transferred from the front opening 40 to the outside of the chamber 12. Even if it leaks into the (work space 16), the air can flow into the air circulation first duct 17 by the first and second air barriers, and the outside of the safety cabinet 10 of the leaked air to the outside of the chamber 12 Leakage and diffusion to (chamber 11) can be prevented.

  Since the safety cabinet 10 prevents leakage and diffusion of air leaking outside the chamber 12 (work space 16) to the outside (room 11) of the safety cabinet 10 during use of the work chamber 12, Contamination of air leaking outside to the outside of the safety cabinet 10 can be prevented, and surrounding contamination by microorganisms such as bacteria and viruses and fine dust can be prevented.

  In use operation, the safety cabinet 10 causes the air that has been passed through the first filter 26 by the first blower 23 to flow from the upper side to the lower side of the working chamber 12, and the first air from the vicinity of the front opening 40. While being introduced into the air flow path 13, the second air flow path 14 is guided to the third air flow path 13 and a part of the air is again flowed into the chamber 12. Clean air in which microorganisms such as viruses and viruses and fine dust are collected can be allowed to flow into the chamber 12 at all times, and the chamber 12 can be kept clean, as well as the second and third blowers 24. , 25 is supplied to the floor surface 46 of the work space 12 by the air that has been passed through the third and fourth filters 28, 29 by the third and fourth filters 28, 29. 4 by the filter 29 can microorganisms and fine dust such as bacteria and viruses supply always working space 16 the collected clean air, it is possible to keep the space 16 clean.

  The safety cabinet 10 is supplied from the second air supply port 22 by making the wind speed of the air supplied from the third blower 25 faster than the wind speed of the air supplied from the second blower 24 in the use operation. The barrier function of the second air barrier (air curtain) formed from the fresh air can be improved, and air leaked to the outside of the working chamber 12 (work space 16) or the first air supply port 21 is supplied. The air that has been discharged does not leak to the outside of the air supplied from the third blower 25 (second air barrier), and the air that has leaked to the outside of the chamber 12 from the front opening 40 is the first air supply port. Even if the air passes through the first air barrier formed by the air supplied from the air 21, the air can flow into the air circulation first duct 17 by the second air barrier. It is possible to prevent the leakage or diffusion of the safety cabinet 10 of the air leaked to the outside of the 12 to the outside (chamber 11).

  The safety cabinet 10 increases the flow rate of air supplied from the second blower 24 (first air supply port 21) more than the flow rate of air supplied from the third blower 25 (second air supply port 22). Thus, since a large amount of air passed through the third filter 28 by the second blower 24 can be supplied toward the floor surface 46 of the work space 16, microorganisms such as bacteria and viruses can be supplied by the third filter 28. In addition, clean air in which fine dust is collected can be supplied to the work space 16 at all times, and the work space 16 can be kept clean during use operation.

  The safety cabinet 10 can maintain the air cleanliness level in the working chamber 12 at grade A in the idling operation, the preparation operation, and the use operation, and the air cleanliness level in the work space 16 at the grade B. Therefore, a room with a cleanliness level of grade A as in the prior art is created, and only one safety cabinet is installed in the room, and the cleanliness level is around grade B. Compared to the case where multiple chambers such as a gas chamber, degauning chamber, buffer area, supply chamber, etc. are prepared, a plurality of safety cabinets are provided in one room 11 having a cleanliness level of air of grade C or grade D. 10 can be installed, and it is not necessary to construct a large-scale facility for installing the safety cabinet 10.

DESCRIPTION OF SYMBOLS 10 Safety cabinet 11 Room 12 Working chamber 13 1st air flow path 14 2nd air flow path 15 3rd air flow path 16 Working space 17 Air circulation 1st duct 18 Air circulation 2nd duct 19 1st air inflow port 20 1st 2 air inlets 21 first air inlet 22 second air inlet 23 first blower 24 second blower 25 third blower 26 first filter 27 second filter 28 third filter 29 fourth filter 30 fifth filter 31 Human sensor 32 Open / close sensor 33 Controller 39 Front shutter 40 Front opening 41 Air inflow opening 46 Floor 49 Rear area 50 Central area 51 Front area 52 User

Claims (13)

A working chamber having a predetermined volume having a front opening that is opened and closed by a front shutter and having a first filter installed at the top; a first air flow path that is positioned below the working chamber and extends in the front-rear direction; A second air flow path that is located behind the working chamber and is connected to the first air flow path and extends in the vertical direction, and a front and rear direction that is located above the working chamber and is connected to the second air flow path. A third air flow path extending to the work chamber, and a first blower that causes air to flow from the upper side to the lower side of the working chamber, thereby preventing contamination between the working chamber and the outside. In the cabinet
The safety cabinet is positioned behind the second air flow path and extends in the up-down direction, and is connected to the first duct and positioned above the third air flow path in the front-rear direction. An air circulation second duct extending; a working space having a predetermined volume located in front of the working chamber; and a first volume extending below the first air flow path. A first air inlet through which air flows in from the bottom of the duct; a second air inlet through which air flows into the second duct from the third air channel; and a second air inlet from the third air channel into the second duct. A second filter that filters inflowing air; a first air supply port that is located in a rear area and a central area of the work space and supplies air to the work space; and the second duct that is installed in the second duct. 1st air supply A second blower for supplying air from the opening toward the floor of the work space; a third filter for filtering air supplied to the work space by the second blower; and the first air supply opening. A second air supply port that is located in front of and supplies air to the work space; and an air that is installed in the second duct and flows from the second air supply port toward the floor of the work space. A third blower for supplying air,
In the safety cabinet, when the user exists in the work space and the front opening of the work chamber is open, the air that has been passed through the first filter by the first blower is used in the work chamber. Part of the air by flowing from the second air flow path to the third air flow path while flowing the air from the vicinity of the front opening to the first air flow path. Is again introduced into the working chamber, and the remainder of the air is caused to flow into the second duct from the second air inlet while flowing through the second filter, and further flows through the second duct. Air is supplied from the first air supply port toward the floor of the work space while flowing air through the third filter by the second blower, and flows through the second duct. Air is supplied from the second air supply port toward the floor of the work space by the third blower, and the air directed toward the floor flows into the first duct from the first air inlet. The air-fuel mixture of the air flowing into the second duct from the second air inlet and the air flowing into the second duct from the first duct toward the floor surface A safety cabinet capable of preventing contamination, characterized by carrying out use operation to supply air again.   2. The safety cabinet capable of preventing contamination according to claim 1, wherein in the use operation, a wind speed of air supplied from the third blower is faster than a wind speed of air supplied from the second blower.   In the safety cabinet, when the user is present in the working space and the front opening of the working chamber is closed by the shutter, the air flowing through the second duct is caused to flow by the second blower by the third blower. Air is supplied from the first air supply port toward the floor of the work space while flowing through the filter, and air flowing through the second duct is supplied from the second air supply port by the third blower. Air is supplied toward the floor surface of the work space, and the air directed toward the floor surface is allowed to flow into the second duct while flowing into the first duct from the first air inlet, and from the first duct, The safety cabinet capable of preventing contamination according to claim 1 or 2, wherein a preparatory operation is performed in which air that has flowed into the second duct is supplied again toward the floor surface. Tsu door.   4. The safety cabinet capable of preventing contamination according to claim 3, wherein in the preparatory operation, a wind speed of air supplied from the third blower is higher than a wind speed of air supplied from the second blower.   5. The contamination prevention according to claim 3, wherein in the preparation operation, a wind speed of air supplied from the second blower is faster than a wind speed of air supplied from the second blower in the use operation. Safety cabinet.   In the safety cabinet, when the user does not exist in the working space and the front opening of the working chamber is closed by the shutter, the second blower does not supply air, and the second blower does not supply air. The air flowing through the duct is supplied from the first air supply port toward the floor surface of the work space while flowing air through the third filter by the second blower, and the air directed toward the floor surface is An idling operation is performed in which the air that has flowed into the second duct is introduced from the first air inlet to the second duct, and the air that has flowed into the second duct from the first duct is supplied again toward the floor surface. A safety cabinet capable of preventing contamination according to any one of claims 1 to 5.   7. The contamination prevention according to claim 6, wherein in the idling operation, a wind speed of air supplied from the second blower is slower than a wind speed of air supplied from the second blower in the use operation and the preparation operation. Safety cabinet.   In the preparatory operation and the idling operation, the air that has been passed through the first filter by the first blower is caused to flow downward from the upper side of the working chamber, and the air is passed from the vicinity of the front opening to the lower side. The contamination prevention according to claim 6 or 7, wherein the air is introduced from the second air flow path to the third air flow path while flowing into the working chamber while flowing into the first air flow path. Safety cabinet.   The safety cabinet includes first detection means for detecting entry or exit of the user into the work space, and second detection means for detecting opening or closing of the front opening. In the safety cabinet, When the first detection means detects the user's entry, and the second detection means detects the opening of the front opening, the use operation is performed, and the first detection means detects the user's entry. And when the second detection means detects that the front opening is closed, the preparatory operation is performed, and the first detection means detects the exit of the user, and the second detection means The contamination according to any one of claims 6 to 8, wherein the idling operation is performed when the closing of the front opening is detected by. Stop possible safety cabinet.   The said safety cabinet contains the 4th filter which filters the air supplied by the said 3rd air blower, and the 5th filter which filters the air which flows in into the said 1st duct from the said 1st air inflow port. A safety cabinet capable of preventing contamination according to claim 9.   The safety cabinet includes side panels located on both lateral sides of the work space. In the safety cabinet, the work space is surrounded by the first and second ducts, the side panel, and the floor surface. The safety cabinet capable of preventing contamination according to any one of claims 1 to 10, wherein an opposite side of the working chamber is opened.   The second air supply port is a slit that extends between the one side panel and the other side panel across the work space, and air supplied from the third blower passes through the slit. The safety cabinet capable of preventing contamination according to claim 11, wherein an air curtain is formed to block air from entering from outside the work space. In the safety cabinet, the cleanliness level of air inside the working chamber is Grade A, the cleanliness level of air in the working space is Grade B, and the cleanliness level of air outside the working space is Grade. The safety cabinet capable of preventing contamination according to any one of claims 1 to 12, which is C or grade D.

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