Fume hoods with ventilation openings

Abstract

A fume hood equipped with an air passage opening comprises an inner cavity of the cabinet for testing and a cavity wall body for constructing the inner cavity of the cabinet, comprising a left cavity side wall, a right cavity side wall and a cavity back wall arranged between the left cavity side wall and the right cavity side wall, a lintel plate and an operation window located below the lintel plate are arranged opposite to the cavity back wall, the operation window is used to form an inlet and outlet passage for conducting experiments, and a guide back plate is also arranged in the inner cavity of the cabinet, the guide back plate is located in front of the cavity back wall and there is a spacing between them to form an exhaust duct; the left and right side edges of the guide back plate extend close to the left cavity side wall and the right cavity side wall respectively, wherein the two side edges of the guide back plate located in the middle or upper area of ​​the inner cavity of the cabinet and the left cavity side wall and the right cavity side wall respectively have gradually expanding air passage openings, and the gradually expanding air passage openings are in a geometric shape that gradually increases from the bottom to the top; from the main viewing direction, the top end of the gradually expanding air passage opening approaches or extends into the projection of the lintel plate.

Description

Technical Field

[0001] The invention relates to ventilation equipment for a laboratory, in particular to a fume hood equipped with a wind opening. Background Art

[0002] Various harmful gases will be generated during chemical experiments. In order to be able to immediately discharge the harmful gases nearby, fume hoods are often used. Fume hoods are common local exhaust systems in chemical laboratories. They can exhaust harmful gases with a small amount of air, control the diffusion of harmful gases generated in the experiment to the laboratory, and ensure the health and safety of the experimenters. Common fume hoods mainly include a support table for experimental operations, a cabinet cavity arranged above the support table, and an exhaust fan connected to the cabinet cavity. The fume hood is also provided with an operating window to form an inlet and outlet channel for experiments on the support table for experimenters to perform experimental operations. A lintel plate is fixed above the operating window. Harmful gases are extracted from the cabinet cavity by the exhaust fan. All specifications require that the operating window position of the fume hood has a stable surface wind speed, and the amount of harmful gas leakage to the outside must be controlled to a very low level.

[0003] After long-term experiments and research, it was found that the provision of a guide back plate in the cabinet cavity is beneficial to reducing the generation of eddies and can also help to form a stable surface wind speed at the operating window. The guide back plate is generally arranged in the cabinet cavity and is arranged vertically like a screen (half of the vertical angle is between 75° and 90°) in front of the cavity back wall constituting the cabinet cavity, and an air duct is formed between the guide back plate and the cavity back wall to discharge the toxic gas in the cabinet cavity to the exhaust fan. However, the shapes and structures of the guide back plates of existing fume hoods vary. For example, the Chinese invention patent application with patent number 201710939219.1 and patent name fume hood discloses the following guide back plate mechanism: a plurality of through holes are provided on the guide back plate, and the through holes located at the lower part of the guide back plate are evenly distributed along the horizontal width direction; the through holes located at the upper part of the guide back plate gradually decrease from bottom to top in terms of the hole area relative to the unit area. In other embodiments, the through holes provided on the upper part of the guide back plate are gradually spaced apart from each other from bottom to top, the arrangement is gradually sparse, or the area of ​​a single hole is gradually reduced. In another embodiment, the through holes provided on the upper part of the guide back plate are arranged radially from top to bottom in the width direction, that is, when viewed from the front side, the arrangement of the through holes is narrow at the top and wide at the bottom along the center. Alternatively, the Chinese utility model patent with patent number CN201320231068.1 and patent name fume hood guide back plate discloses the following guide back plate: a fume hood guide back plate, comprising a plate body, exhaust holes are provided on the upper, lower, left, right sides and middle of the plate body, and the distances from the exhaust holes on the upper, lower, left and right sides of the plate body to the corresponding side edges of the plate body are equal. Experiments have found that the ventilation effect of the fume hood using the above two guide back plates is not ideal, and there is a phenomenon of some harmful gases leaking out. Summary of the invention

[0004] The guide structure of the guide back plate will affect the exhaust effect in the fume hood and also affect the airflow movement characteristics in the space in front of the guide back plate. Its structure directly affects the fume hood's ability to capture harmful gases. The above two guide back plates disclosed in the existing patents 201710939219.1 and 201320231068.1 actually have common defects, including: since the fume hood generally mainly replenishes air to the horizontal middle space of the cabinet cavity, and the amount of air replenished to the left and right side spaces of the cabinet cavity, especially the middle or upper left and right side spaces of the cabinet cavity, is relatively small, resulting in low exhaust efficiency of the middle or upper left and right side spaces of the cabinet cavity. Some of the lightweight gases that escape from the lower space of the cabinet cavity will drift upward and accumulate in the middle or upper space of the cabinet cavity, and form very bad vortices in the corner spaces on both sides of this space, resulting in the harmful gases accumulated in the corner spaces on both sides cannot be discharged in time for a long time, and even due to the suction effect of the vortex, they are easy to escape from the operating window to the outside of the fume hood, endangering the health of the operator. Although there is a gap with uniform width from top to bottom between the guide back plate and the left and right side walls in the cabinet cavity, which can discharge a small amount of lightweight gas into the air duct behind the guide back plate, relying solely on the gap with uniform width from top to bottom is not enough to solve this problem.

[0005] In order to solve the above technical problems, the inventor tried to open hollow air guide structures that allow air to flow on the left and right sides of the upper part of the guide back plate, such as multiple horizontally arranged guide grooves, multiple evenly arranged guide holes, etc. However, after experiments, it was found that although some vortices were improved, they were only slightly weakened, and there were still a large number of harmful gases swirling in the left and right corner spaces of the upper or middle space of the cabinet cavity. Therefore, it is not feasible to simply configure the guide structure, and how to configure a suitable guide structure still requires further in-depth research. In the subsequent multiple airflow tests, the inventor noticed a factor that cannot be ignored, that is, the changing trend of the air pressure distribution under the action of the exhaust fan during the operation of the fume hood, that is, the farther away from the exhaust fan, the smaller the air pressure, and on the contrary, the closer to the exhaust fan, the greater the air pressure, which has a great impact on the airflow distribution, and it is necessary to reasonably configure the position, ventilation area, shape and other parameters of the guide mechanism in accordance with this feature. Therefore, the inventor tried to open multiple rows of horizontally extending long strip air guide grooves arranged at intervals on the left and right sides of the upper part of the guide back plate, and the area of ​​the long strip air guide grooves gradually decreases from bottom to top, but the effect is still not ideal. This proves that simply making the ventilation area of ​​the air guide grooves have a regular change is still not able to solve the above technical problems.

[0006] How to allow the relatively light harmful gases accumulated in the upper or middle part of the cabinet cavity, especially in the left and right corner spaces, to enter the air duct on the back of the guide back plate as much as possible by changing the structure of the guide back plate is one of the technical problems to be solved by the present invention. In view of this, the present invention proposes a fume hood equipped with a through-wind opening, including a cabinet cavity for testing and a cavity wall body used to construct the cabinet cavity, the cavity wall body including a left cavity side wall, a right cavity side wall and a cavity back wall arranged between the left cavity side wall and the right cavity side wall, a lintel plate and an operating window located below the lintel plate are arranged opposite to the cavity back wall, the operating window is used to form an entry and exit channel for conducting experiments, and a guide back plate is also arranged in the cabinet cavity, the guide back plate is located in front of the cavity back wall and they are connected. There is a spacing between them to form an exhaust duct; it is characterized in that the left and right side edges of the guide back plate extend close to the left cavity side wall and the right cavity side wall respectively, wherein the side edges of the guide back plate located in the middle or upper area of ​​the cabinet cavity and the left cavity side wall and the right cavity side wall respectively have gradually expanding air openings, and the gradually expanding air openings are in a geometric shape that gradually becomes larger from the bottom to the top; viewed from the main viewing direction, the top end of the gradually expanding air opening approaches or extends into the projection of the lintel plate.

[0007] The inner cavity of the cabinet is an operating space for conducting various experimental activities. With the help of the inner cavity of the cabinet, harmful gases generated during the experiment can be temporarily collected therein to prevent them from spreading around.

[0008] The guide back plate is located in the cabinet cavity, in front of the cavity back wall, and the guide back plate and the cavity back wall can be arranged roughly parallel to each other, or the guide back plate is arranged obliquely relative to the cavity back wall, forming an air duct for exhaust between them.

[0009] Among them, the left and right side edges of the guide backplate extend close to the left cavity side wall and the right cavity side wall respectively. The above characteristics define that it includes the left and right side edges of the guide backplate (excluding the part used to form the gradually expanding air opening) which can be close to the left cavity side wall and the right cavity side wall respectively, and can also be respectively left with a certain appropriate spacing in the left and right directions between the left and right cavity side walls. The width of the spacing is generally 1mm to 20mm, and the specific spacing size is determined according to other specific air inlet structures of the fume hood, the exhaust power of the exhaust fan, the applicable scope of the fume hood and other factors.

[0010] Among them, the gradually expanding air opening is a geometric shape that gradually becomes larger from the bottom to the top. The above characteristics define the shape of the gradually expanding air opening. The gradually expanding air opening is an air guide gap that extends continuously in the up and down directions and whose width varies with height, with the upper part being larger and the lower part being smaller.

[0011] Among them, the two side edges of the guide back plate located in the middle or upper area of ​​the cabinet cavity and the left cavity side wall and the right cavity side wall respectively have gradually expanding air openings. The above characteristics define the layout position of the gradually expanding air openings, which are located on the left and right sides of the middle or upper area of ​​the cabinet cavity.

[0012] Among them, from the main viewing direction, the top end of the gradually expanding air opening approaches or extends into the projection of the lintel plate. The above characteristics define the relative positional relationship between the gradually expanding air opening and the lintel plate in the up and down directions. Specifically, it can be: from the main viewing direction, the top end of the gradually expanding air opening is not far from the lower edge of the lintel plate, for example, the distance can be 20mm to 50mm; or the top end of the gradually expanding air opening is connected to the lower edge of the lintel plate; or the top end of the gradually expanding air opening is hidden behind the lintel plate. In addition, the definition of the viewing direction from the main viewing direction is a viewing angle direction, that is, the direction in which the observer stands on the front of the fume hood, faces the operating window and observes from front to back. Unless otherwise specified, the "viewed from the main viewing direction" mentioned below has the same meaning.

[0013] According to the above technical scheme, compared with the prior art, the beneficial technical effects of the present invention are: First, due to the gradually expanding air opening configured with the above-mentioned specific shape and arranged at the above-mentioned specific position, that is, relatively large air guide gaps arranged continuously from top to bottom are formed on the left and right sides of the guide back plate respectively, thereby providing a flow channel for the relatively light small molecule gases that rise and accumulate in the left and right corner spaces on the upper or middle part of the cabinet cavity to be discharged into the exhaust duct in time, and also helping to reduce the resistance of airflow and the formation of vortices, thereby increasing the airflow speed. Second, when the fume hood is configured with an intake airflow as the control airflow and forms an air pressure gradient that gradually increases from bottom to top in the inner cavity of the hood, there will be a certain intake speed gradient between the highest and lowest points of the gradually expanding air opening. By utilizing the shape change of the gradually expanding air opening, that is, a geometric shape that gradually increases from the bottom to the top, it is beneficial to form a larger suction force at the upper part of the gradually expanding air opening than at the lower part, thereby being able to suck in more relatively light small molecule gases that drift upward and accumulate in the left and right corner spaces on the upper or middle part of the inner cavity of the hood, and can further reduce the formation of vortices.

[0014] In order to form the gradually expanding airflow opening, the following technical solutions can be further selected, wherein the first technical solution is: the guide back plate has a narrowing plate portion, and the two side edges of the narrowing plate portion gradually narrow towards each other from bottom to top in an inclined manner, and the left cavity side wall and the right cavity side wall respectively have vertical wall portions arranged corresponding to the narrowing plate portion and in an upright shape, and the gradually expanding airflow openings arranged on the left and right are respectively formed between the left and right side edges of the narrowing plate portion and the vertical wall portions of the left cavity side wall and the right cavity side wall. The second technical solution is: the left and right cavity side walls respectively have concave wall portions, and the concave wall portions are in a shape of gradually concave outward from bottom to top, and the guide back plate has vertical plate portions arranged corresponding to the concave wall portions and the two side edges are respectively in an upright shape, and the gradually expanding airflow openings arranged on the left and right are respectively formed between the concave wall portions of the left and right cavity side walls and the two side edges of the vertical plate portions.

[0015] In order to provide an appropriate amount of make-up air to the gradually expanding air opening, a further technical solution may be that vertical columns are respectively arranged on the left and right sides of the operating window, the left and right vertical columns are distributed and connected to the left cavity side wall and the right cavity side wall, the left and right vertical columns are hollow and have make-up air passages formed therein, the left and right vertical columns respectively include rear column walls facing the rear of the cabinet cavity, inner air outlets arranged in the up and down directions are arranged on the rear column walls, the highest horizontal height of the inner air outlet is lower than the highest horizontal height of the gradually expanding air opening, the inner air outlet is connected to the make-up air passage, and the inner air outlet is used to supply air to the rear direction of the cabinet cavity. According to the above technical solution, the inner air outlets on the left and right vertical columns are located on the left and right sides of the operating window, so as to provide suitable air supply for the left and right spaces of the cabinet cavity and the gradually expanding air opening, and bring the harmful gases floating in the left and right spaces of the cabinet cavity into the gradually expanding air opening; in addition, the highest level of the inner air outlet is lower than the highest level of the gradually expanding air opening, so that, from the main viewing direction, at least part of the opening of the gradually expanding air opening is located above the inner air outlet. The positional relationship between the gradually expanding air opening and the inner air outlet is various, for example, it can be: from the main viewing direction, the gradually expanding air opening is located above the inner air outlet as a whole, and they are arranged at intervals from top to bottom, or the lower part of the gradually expanding air opening is hidden directly behind the upper part of the inner air outlet. In this way, under the suction force of the gradually expanding air opening, at least part of the airflow entering the cabinet cavity through the inner air outlet will flow from bottom to top, so that both heavier and lighter harmful gases can be captured from bottom to top, thereby increasing the discharge amount and capture range of harmful gases; secondly, since the inner air outlet is used to supply air toward the rear direction of the cabinet cavity, the airflow blown out from the inner air outlet can intercept at least part of the harmful gases escaping toward the operating window, and further bring them into the cabinet cavity, reducing the leakage of harmful gases.

[0016] As for the structural form of the inner air outlet, it can be various. For example, the inner air outlet can be a plurality of through holes intermittently arranged along the up and down directions; or the inner air outlet can be an air outlet slot continuously extending along the up and down directions.

[0017] A further technical solution may be that the inner air outlet is used to supply air to the inner cavity of the cabinet along a direction perpendicular to the plane of the operating window. In this way, the airflow blown out from the inner air outlet can flow to the inner cavity of the cabinet along a direction perpendicular to the plane of the operating window.

[0018] In order to supply air to the air supply channel, a further technical solution may be that the left cavity side wall and the right cavity side wall respectively include an inner plate and an outer plate, the inner plate and the outer plate are arranged at intervals on the left and right to form a sandwich cavity between them, a hollow wind box is arranged in the sandwich cavity, an air inlet box hole is arranged on the top wall of the wind box, and an air outlet box hole is arranged on the front side wall; the cavity wall body also includes a cavity top wall, an air inlet passage is arranged on the cavity top wall, the air inlet passage is connected to the air inlet box hole, and the air outlet box hole is connected to the air supply channel. According to the above technical solution, a blower connected to the air inlet passage can be provided, and the blower is used to actively force air to be supplied to the air supply channel.

[0019] A further technical solution may be that the inner air outlet is close to the inner panel. In this way, from the main viewing direction, the distance between the inner air outlet and the inner panel is smaller than the distance between the inner air outlet and the outer wall edge of the rear column wall, and the gap between the inner air outlet and the inner panel in the left-right direction is very small, for example, 1mm to 5mm, or even 0mm. In this way, part of the airflow blown out from the inner air outlet can flow close to the inner panel. On the one hand, the guiding effect of the inner panel can be used to form a steady flow and reduce the generation of vortices; on the other hand, harmful gases remaining on the inner panel or floating in the area near the inner panel can be cleaned and adsorbed, thereby increasing the removal effect of harmful gases.

[0020] Since the present invention has the above characteristics and advantages, it can be applied to a fume hood equipped with a wind opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional structural schematic diagram of a fume hood to which the technical solution of the present invention is applied;

[0022] Figure 2 is a schematic structural diagram of a fume hood in a main view direction to which the technical solution of the present invention is applied, wherein the movable door 7 is omitted;

[0023] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure in the AA direction;

[0024] Figure 4 yes Figure 2 Schematic diagram of the cross-sectional structure in the BB direction;

[0025] Figure 5 2 is a schematic structural diagram of the guide back plate 2 in the main viewing direction, wherein the left and right dotted line parts respectively represent the left cavity side wall 11 and the right cavity side wall 11a, and the dotted line part below represents the support platform 12;

[0026] Figure 6 It is a schematic diagram of the top view of the structure of a fume hood to which the technical solution of the present invention is applied;

[0027] Figure 7 yes Figure 6 Schematic diagram of the cross-sectional structure in the DD direction;

[0028] Figure 8 is a schematic cross-sectional structure diagram of a vertical column using another embodiment;

[0029] Fig. 9 is a schematic structural diagram of the second positional relationship between the gradually expanding air opening and the lintel plate;

[0030] Fig.10 It is a structural schematic diagram of the gradually expanding air opening and the door lintel plate adopting a third positional relationship. DETAILED DESCRIPTION

[0031] The structure of the fume hood using the technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0032] like Figures 1 to 6 The fume hood shown includes a test bench 12, a test cabinet cavity 1 located above the test bench 12, and a cavity wall body used to construct the cabinet cavity 1, wherein the cavity wall body includes a left cavity side wall 11, a right cavity side wall 11a, and a cavity back wall 13 and a cavity top wall 14 arranged between the left cavity side wall 11 and the right cavity side wall 11a. A total exhaust port 141 is arranged on the cavity top wall 14. A lintel plate 15 and an operating window 70 located below the lintel plate 15 are arranged opposite the cavity back wall 13, and the operating window 70 is used to form an inlet and outlet passage for conducting experiments. The lintel plate 15 is fixed between the vertical column 6 and the vertical column 6a. A guide back plate 2 is also arranged in the cabinet cavity 1, and the guide back plate 2 is located in front of the cavity back wall 13 and there is a spacing between them to form an exhaust duct 8.

[0033] Since the fume hood is generally used to supply air to the horizontal middle space of the cabinet cavity 1, and the amount of air supplied to the left and right spaces of the cabinet cavity 1, especially the left and right spaces of the middle or upper part of the cabinet cavity, is relatively small, some lightweight gases escaping from the lower space of the cabinet cavity 1 will drift upward and accumulate in large quantities in the corner spaces on both sides of the middle or upper space of the cabinet cavity 1, and may even easily escape from the operating window 70 to the outside of the fume hood due to the suction effect of the vortex. In order to solve the above technical problems, the present invention first improves the airflow structure of the guide back plate 2. Figure 2 and Figure 5As shown, the left and right side edges of the guide back plate 2 extend close to the left cavity side wall 11 and the right cavity side wall 11a respectively, wherein the side edges of the guide back plate 2 located in the middle or upper area of ​​the cabinet inner cavity 1 and the left cavity side wall 11 and the right cavity side wall 11a respectively have a gradually expanding air opening 3 and a gradually expanding air opening 3a, and the gradually expanding air opening 3 and the gradually expanding air opening 3a are respectively in a geometric shape that gradually increases from the bottom to the top; when viewed from the main viewing direction (the view obtained from the main viewing direction is Figure 2 and Figure 5 ), the top ends of the gradually expanding air openings 3 and 3a are close to or extend into the projection of the door lintel plate 15 respectively.

[0034] Among them, the left and right side edges of the guide back plate 2 extend close to the left cavity side wall 11 and the right cavity side wall 11a respectively. The above characteristics define that it includes the left and right side edges of the guide back plate 2 (excluding the part used to form the gradually expanding air opening) which can be close to the left cavity side wall 11 and the right cavity side wall 11a respectively, and can also be respectively left with a certain appropriate spacing in the left and right directions between the left cavity side wall 11 and the right cavity side wall 11a. The width W1 of the spacing is generally 1mm~20mm, and the specific spacing size is determined according to other specific air inlet structures of the fume hood, the exhaust power of the exhaust fan, the applicable scope of the fume hood and other factors.

[0035] Among them, from the main viewing direction, the top ends of the gradually expanding air opening 3 and the gradually expanding air opening 3a are close to or extend into the projection of the lintel plate 15, respectively. The above characteristics define the relative positional relationship between the gradually expanding air opening 3 and the gradually expanding air opening 3a and the lintel plate 15 in the up and down directions, which can be specifically: Fig. 9 As shown, from the main viewing direction, the top ends of the gradually expanding air openings 3 and 3a are spaced slightly apart from the lower edge of the lintel plate 15, for example, the distance may be 20 mm to 50 mm; or Fig.10 As shown, the top ends of the gradually expanding air openings 3 and 3a are connected to the lower edge of the door lintel 15 respectively; or, as shown Figure 2 As shown, this embodiment adopts the following technical solution: the top ends of the gradually expanding air opening 3 and the gradually expanding air opening 3a are respectively located directly behind the door lintel 15. In this embodiment, the gradually expanding air opening 3 and the gradually expanding air opening 3a are arranged on the left and right sides of the upper middle part of the cabinet inner cavity 1.

[0036] Combine the following Figure 3 and Figure 5 The structure of the guide back plate 2 is further described. The guide back plate 2 includes a first guide back plate 21, a second guide back plate 22 and a third guide back plate 23 arranged in sequence from bottom to top. The first guide back plate 21 and the second guide back plate 22 are respectively arranged parallel to the cavity back wall 13. Of course, in other embodiments, they can also be arranged relatively tilted. A lower wind gap 4 extending laterally is formed between the first guide back plate 21 and the test bench 12. The height H5 of the middle area of ​​the lower wind gap 4 from the test bench 12 is greater than the height H6 of the left and right ends from the test bench 12. The third guide back plate 23 is arranged in an inclined manner below the main exhaust port 141, so that the exhaust duct 8 is connected to the main exhaust port 141. It also includes an exhaust fan (not shown in the figure), which is connected to the main exhaust port 141. When the exhaust fan is working, it can extract harmful gases entering the exhaust duct 8 from the cabinet cavity 1. In order to form the gradually expanding airflow opening, the airflow guide back plate 2 has a narrowing plate portion, and the two sides of the narrowing plate portion gradually narrow towards each other from bottom to top in an inclined manner. In this embodiment, the second airflow guide back plate 22 is located in the middle and upper part of the cabinet inner cavity 1 and forms the narrowing plate portion. The left cavity side wall 11 and the right cavity side wall 11a respectively have vertical wall portions arranged corresponding to the narrowing plate portion and in an upright shape. The gradually expanding airflow opening 3 is formed between the left side edge 221 of the narrowing plate portion and the vertical wall portion 113 of the left cavity side wall 11; the gradually expanding airflow opening 3a is formed between the left side edge 221a of the narrowing plate portion and the vertical wall portion 113a of the right cavity side wall 11a. The maximum width W2 of the gradually expanding airflow opening 3 and the gradually expanding airflow opening 3a is 40 mm to 60 mm. Of course, in other embodiments, in order to form the gradually expanding air opening, the following technical solution (not shown in the figure) can also be adopted: the left and right cavity side walls respectively have a recessed wall portion, and the recessed wall portion is in a shape that is gradually recessed outward from bottom to top, and the guide back plate has a vertical plate portion arranged corresponding to the recessed wall portion and with two side edges that are respectively upright, and the gradually expanding air openings arranged on the left and right are respectively formed between the recessed wall portions of the left and right cavity side walls and the two side edges of the vertical plate portion.

[0037] Compared with the prior art, the beneficial technical effects achieved by the above technical scheme are: First, due to the gradually expanding air openings 3 and the gradually expanding air openings 3a which are configured with the above specific shapes and arranged at the above specific positions, that is, relatively large air guide gaps which are arranged continuously from top to bottom are formed on the left and right sides of the guide back plate 2, respectively, thereby providing a flow channel for the relatively light small molecule gases which rise and accumulate in the left and right corner spaces of the upper or middle part of the cabinet cavity 1 to be discharged into the exhaust duct 8 in time, and also helping to reduce the resistance of the airflow and the formation of vortices, thereby increasing the airflow speed. Second, when the fume hood is configured with an intake airflow as the control airflow and forms a gradually increasing air pressure gradient from bottom to top in the hood cavity 1, there will be a certain intake speed gradient between the highest point and the lowest point of the gradually expanding air opening 3 and the gradually expanding air opening 3a. By utilizing the shape change of the gradually expanding air opening 3 and the gradually expanding air opening 3a, that is, presenting a geometric shape that gradually increases from the bottom to the top, it is beneficial to form a larger suction force at the upper part of the gradually expanding air opening 3 and the gradually expanding air opening 3a relative to the lower part, so that more relatively light small molecular gases that drift upward and accumulate in the left and right corner spaces of the upper or middle part of the hood cavity 1 can be sucked in, and the formation of vortices can be further reduced.

[0038] In order to provide an appropriate amount of supplementary air to the gradually expanding air opening, the fume hood is provided with an inner side supplementary air structure. Figure 2 and Figure 4 As shown, a vertical column 6 and a vertical column 6a are respectively provided on the left and right sides of the operating window 70. The vertical column 6 on the left is connected to the left cavity side wall 11, and the vertical column 6a on the right is connected to the right cavity side wall 11a. The vertical columns 6 and vertical columns 6a disposed on the left and right have similar structures and technical effects, and the vertical column 6 is taken as an example for description below. The vertical column 6 is hollow and has an air supply channel 60 formed therein. The vertical column 6 includes a rear column wall 61 facing the rear of the cabinet cavity 1. The rear column wall 61 is not facing outside the cabinet cavity 1, and is arranged parallel to the plane of the operating window 70 (of course, in other embodiments, such as Figure 8As shown, the rear column wall 61' may also be arranged slightly tilted relative to the plane of the operating window 70). An inner air outlet 610 arranged in the up-down direction is provided on the rear column wall 61, and the inner air outlet 610 is connected to the air supply channel 60, and the inner air outlet 610 is used to supply air to the rear direction of the cabinet inner cavity 1. Furthermore, the inner air outlet 610 is used to supply air to the cabinet inner cavity 1 in a direction perpendicular to the plane of the operating window 70. In this way, the airflow blown out from the inner air outlet 610 can flow to the cabinet inner cavity 1 in a direction perpendicular to the plane of the operating window 70. Of course, it is also feasible for the inner air outlet 610 to supply air to the cabinet inner cavity 1 in a direction slightly tilted to the plane of the operating window 70. As for the structural form of the inner air outlet 610, it can be various. In the present embodiment, the inner air outlet 610 is a plurality of through holes intermittently arranged along the up and down directions (of course, in other embodiments, the inner air outlet 610 can also be an air outlet slot continuously extending along the up and down directions).

[0039] The layout position of the inner air outlet 610 in the vertical direction will affect the air supply effect, which will be further explained below. Figure 2 As shown, the highest horizontal height H7 of the inner air outlet 610 is lower than the highest horizontal height H8 of the gradually expanding air opening 3. In this way, from the main viewing direction, at least part of the opening of the gradually expanding air opening 3 is located above the inner air outlet 610. Specifically, the positional relationship between the gradually expanding air opening 3 and the inner air outlet 610 is diverse. In this embodiment, from the main viewing direction, the gradually expanding air opening 3 is located above the inner air outlet 610 as a whole, and they are arranged with an interval up and down. Of course, in other embodiments, it can also be that from the main viewing direction, the lower part of the gradually expanding air opening 3 is hidden directly behind the upper part of the inner air outlet 610. The positional relationship between the inner air outlet on the vertical column 6a and the gradually expanding air opening 3a is the same as above, and will not be repeated. According to the above technical solution, the inner air outlet 610 on the vertical column 6 is located on the left side of the operating window 70, and the inner air outlet on the vertical column 6a is located on the right side of the operating window 70, so as to provide suitable air supply for the left and right side spaces of the cabinet cavity 1 and the gradually expanding air opening 3 and the gradually expanding air opening 3a, and bring the harmful gases scattered in the left and right side spaces of the cabinet cavity 1 into the air side gap 3 and the gradually expanding air opening 3a; in addition, when viewed from the main viewing direction (the obtained view is attached Figure 2), the highest horizontal height of the inner air outlet 610 is lower than the highest horizontal height of the gradually expanding air opening 3. Under the suction force of the gradually expanding air opening 3, at least part of the airflow entering the lower space of the cabinet cavity 1 through the inner air outlet 610 will flow from bottom to top, so that both heavier and lighter harmful gases can be captured from bottom to top, thereby increasing the discharge amount and capture range of harmful gases; secondly, since the inner air outlet 610 is used to supply air to the rear direction of the cabinet cavity 1, the inner airflow a blown out from the inner air outlet 610 can intercept at least part of the harmful gases escaping toward the operating window 70, and further bring them into the cabinet cavity 1, thereby reducing the leakage of harmful gases.

[0040] In addition, in the up and down direction, the inner air outlet 610 and the operating window 70 have the following positional relationship: Figure 2 As shown, the upper horizontal frame of the operation window 70 (i.e., the lower edge of the door lintel 15) and the lower horizontal bar 9 (in this embodiment, the lower horizontal bar 9 is the upper surface of the lower air replenisher) jointly define the upper and lower ranges of the operation window 70. From the main viewing direction, the arrangement height of the inner air outlet 610 is between the upper horizontal frame and the lower horizontal bar 9, and the distance H3 from the lower end of the inner air outlet 610 to the lower horizontal bar 9 is smaller than the distance H4 from the upper end of the inner air outlet 610 to the upper horizontal frame. In this way, the inner air outlet 610 is closer to the lower horizontal bar 9 than the upper horizontal frame. In this embodiment, the inner air outlet 610 is arranged corresponding to the lower space of the operation window 70. In this way, the arrangement of the inner air outlet 610 can be omitted near the upper horizontal frame, thereby simplifying the processing of the inner air outlet 610. When a relatively low-power blower is selected, the air volume requirement of the inner air outlet 610 can still be met, thereby achieving the effect of saving energy.

[0041] In order to supply air to the air supply channel 60, the fume hood is further improved. Figure 4As shown, the structure and technical effect of the left cavity side wall 11 are similar to those of the right cavity side wall 11a, and the left cavity side wall 11 is taken as an example for description. The left cavity side wall 11 includes an inner plate 112 and an outer plate 111, and the inner plate 112 and the outer plate 111 are arranged at intervals on the left and right to form an interlayer cavity 110 therebetween. A hollow wind box 5 is arranged in the interlayer cavity 110, and an air inlet box hole (not shown) is arranged on the top wall of the wind box 5, and an air outlet box hole 50 is arranged on the front side wall. The cavity wall body also includes a cavity top wall 14, and an air inlet passage 140 is arranged on the cavity top wall 14, and the air inlet passage 140 is connected to the air inlet box hole, and the air outlet box hole is connected to the air supply channel 60. According to the above technical solution, a blower connected to the air supply port can be arranged, and the blower is used to actively force air to the air supply channel 60.

[0042] like Figure 2 and Figure 7 As shown, the inner air outlet 610 is close to the inner plate 112, so that when viewed from the main viewing direction (the resulting view is Figure 2 ), the distance between the inner air outlet 610 and the inner panel 112 is smaller than the distance between the inner air outlet 610 and the outer wall edge of the rear column wall 61. In this embodiment, from the main viewing direction, the inner air outlet 610 is close to the inner panel 112, that is, the gap between the inner air outlet 610 and the inner panel 112 in the left-right direction is 0mm. Of course, in other embodiments, there can also be a very small gap between the inner air outlet 610 and the inner panel 112 in the left-right direction, for example, 1mm to 5mm. In this way, part of the airflow blown out from the inner air outlet 610 can flow close to the inner panel 112. On the one hand, the guiding effect of the inner panel 112 can be used to form a steady flow and reduce the generation of vortices; on the other hand, the harmful gas remaining on the inner panel 112 or floating in the area near the inner panel 112 can be cleaned and adsorbed, thereby increasing the removal effect of harmful gas.

[0043] Due to the movement of people, the switching of the opening and closing states of doors and windows in the test room, etc., the indoor air pressure will fluctuate violently, thereby causing varying degrees of damage to the flow path of the external air supply airflow of the fume hood and increasing the leakage of harmful gases. In order to solve the above technical problems, the present invention further proposes a dual air supply structure. The following dual air supply structure can be used alone, and can also be used in the same fume hood product together with the gradually expanding air opening 3 and the gradually expanding air opening 3a.

[0044] like Figure 4As shown, any one of the vertical columns disposed on the left and right also includes an intermediate side column wall arranged opposite to the other vertical column on the opposite side, that is, the intermediate side column wall 62 on the vertical column 6 on the left side faces the vertical column 6a on the right side, and the intermediate side column wall 62a on the vertical column 6a on the right side faces the vertical column 6 on the left side. The intermediate side column wall 62 and the intermediate side column wall 62a form the left and right side walls of the operating window 70. The vertical column 6 and the vertical column 6a have similar structures, and the vertical column 6 is taken as an example for description below. The intermediate side column wall 62 of the vertical column 6 is arranged in a direction perpendicular to the plane of the operating window 70, and an outer air outlet 620 arranged in the up-down direction is provided on the intermediate side column wall 62, and the outer air outlet 620 is used to supply air to the area defined by the operating window 70, and the outer air outlet 620 supplies air to the area defined by the operating window 70 in a direction parallel to the plane of the operating window 70 (of course, in other embodiments, for example Figure 8 As shown, the middle side column wall 62' can also be arranged slightly inclined toward the cabinet inner cavity 1 relative to the plane of the operating window 70, and the outer air outlet 620' can also supply air to the area defined by the operating window 70 in a direction slightly inclined to the plane of the operating window 70, and the airflow passes through the area defined by the operating window 70 and enters the cabinet inner cavity 1). For the convenience of the following discussion, the airflow delivered from the outer air outlet 620 is called the outer airflow b. The air outlet area of ​​the outer air outlet 620 is smaller than the air outlet area of ​​the inner air outlet 610. The outer air outlet 620 is located on the outside of the inner air outlet 610 and forms a double air supply structure with the inner air outlet 610, which can double intercept harmful gases. As for the structural form of the outer air outlet 620, it can be various. In this embodiment, the outer air outlet 620 is a plurality of through holes intermittently arranged in the up and down directions. Of course, in other embodiments, the outer air outlet 620 may also be an air outlet slot that extends continuously in the up-down direction.

[0045] Compared with the prior art, the beneficial technical effects of the above technical solution are: first, since the inner air outlet 610 is used to supply air to the cabinet cavity 1, it can provide a suitable amount of supplementary air for the side space of the cabinet cavity 1, and can discharge as much harmful gas accumulated in the side space of the cabinet cavity 1 as possible, thereby reducing the amount of harmful gas leakage. Second, since the outer air outlet 620 is used to supply air to the area defined by the operating window 70, it can form a wind curtain in the area defined by the operating window 70, and use the wind curtain to prevent the harmful gas in the cabinet cavity 1 from escaping to the outside, thereby reducing the amount of harmful gas leakage. Third, since the outer air outlet 620 is located outside the inner air outlet 610, and the air outlet area of ​​the outer air outlet 620 is smaller than the air outlet area of ​​the inner air outlet 610, the air volume of the outer air outlet 620 is smaller than the air volume of the inner air outlet 610, so that the inner air outlet 610 can be used to deliver the relatively strong inner air flow a that flows toward the cabinet inner cavity 1 on the inner side of the outer air outlet 620, and the traction force of the inner air flow a toward the cabinet inner cavity 1 is used to pull the air out of the outer air outlet 620. At least part of the outer airflow b delivered by the port 620 is brought into the cabinet inner cavity 1, and in this process, at least part of the outer airflow b is used to capture the harmful gas that escapes from the inner airflow a and continues to flow outward and flows back into the cabinet inner cavity 1; in addition, the traction force of the inner airflow a can also be used to weaken the degree of damage to the flow path of the outer airflow b caused by the drastic fluctuation of the internal air pressure of the laboratory, so that at least part of the outer airflow b can flow to the cabinet inner cavity 1 relatively stably, reducing the leakage of harmful gases.

[0046] Further, such as Figure 3 As shown, the upper horizontal frame of the operation window 70 (i.e., the lower edge of the door lintel 15) and the lower horizontal bar 9 (in this embodiment, the lower horizontal bar 9 is the upper surface of the lower air replenisher) jointly define the upper and lower ranges of the operation window 70. From the main viewing direction, the arrangement height of the outer air outlet 620 is between the upper horizontal frame and the lower horizontal bar, and the distance H1 from the lower end of the outer air outlet 620 to the lower horizontal bar is smaller than the distance H2 from the upper end of the outer air outlet 620 to the upper horizontal frame. In this way, the outer air outlet 620 is closer to the lower horizontal bar than the upper horizontal frame. In this embodiment, the outer air outlet 620 is arranged in the lower space of the operation window 70. The arrangement of the outer air outlet 620 can be omitted in the area close to the upper horizontal frame, so that the processing of the outer air outlet 620 can be simplified. When a relatively low-power blower is selected, the air volume requirement of the outer air outlet 620 can still be met, thereby achieving the effect of energy saving.

[0047] Further, such as Figure 4 As shown, the cabinet further includes a movable door 7 capable of closing or opening the operating window 70, and the outer air outlet 620 is located outside the movable door 7. That is, the outer air outlet 620 is farther away from the cabinet inner cavity 1 than the movable door 7, and the movable door 7 is located between the outer air outlet 620 and the cabinet inner cavity 1. In this way, even if harmful gas escapes to the outside of the movable door 7, it can be intercepted by the airflow blown out by the outer air outlet 620 and further brought back into the cabinet inner cavity 1, thereby reducing the amount of harmful gas leakage.

[0048] Further, such as Figure 4 As shown, from the cross-sectional direction perpendicular to the length direction of the vertical column 6 (the observed view is attached Figure 4 ), the vertical column 6 also includes a bending portion, the bending portion includes a transverse wall 63 arranged roughly parallel to the rear column wall 61 and a connecting wall 64 arranged between the rear column wall 61 and the transverse wall 63, the rear column wall 61, the transverse wall 63 and the connecting wall 64 cooperate to define a accommodating cavity 67 with an opening, the opening of the accommodating cavity on any one of the vertical columns disposed on the left and right is arranged opposite to the opening of the accommodating cavity on the other vertical column opposite, that is, the opening of the accommodating cavity 67 on the vertical column 6 is arranged opposite to the opening of the accommodating cavity on the opposite vertical column 6a, and a guide rail 66 for guiding the movement of the movable door 7 is arranged in the accommodating cavity 67. The movable door 7 includes a door panel 71 and rollers 72 arranged on the left and right sides of the door panel 71, and the rollers 72 are arranged on the guide rail 66; the inner air outlet 610 is arranged on the wall body between the guide rail 66 and the plate edge of the door panel 71 on the rear side column wall 61. In this way, the movable door 7 can move along the guide rail 66 on the inner side of the inner air outlet 610, and the door panel 71 will not completely cover the inner air outlet 610. The bending portion also includes a first clamping arm 65 that is substantially perpendicular to the transverse wall 63 and connected to the transverse wall 63, and a second clamping arm 661 is arranged on the guide rail 66 to cooperate with the first clamping arm 65 to form a clamping groove, and the outer end of the inner panel 112 is clamped between the first clamping arm 65 and the second clamping arm 661. In this way, the installation of the inner panel 112 is facilitated.

Claims

1. A fume hood equipped with a through-wind opening, comprising a cabinet cavity for testing and a cavity wall body for forming the cabinet cavity, the cavity wall body comprising a left cavity side wall, a right cavity side wall, and a cavity back wall and a cavity top wall arranged between the left cavity side wall and the right cavity side wall, a total exhaust port is arranged on the cavity top wall, a lintel plate and an operating window located below the lintel plate are arranged opposite to the cavity back wall, the operating window is used to form an inlet and outlet passage for conducting experiments, a guide back plate is also arranged in the cabinet cavity, the guide back plate is located in front of the cavity back wall and there is a spacing between them to form an exhaust duct, an exhaust fan is connected to the total exhaust port, and when the exhaust fan is working, harmful gases entering the exhaust duct can be extracted from the cabinet cavity; characterized in that The left and right side edges of the guide backplate extend close to the left cavity side wall and the right cavity side wall respectively, wherein the side edges of the guide backplate located in the middle or upper area of ​​the cabinet cavity and the left cavity side wall and the right cavity side wall respectively have gradually expanding air openings, and the gradually expanding air openings are in a geometric shape that gradually increases from the bottom to the top; when viewed from the main viewing direction, the top end of the gradually expanding air opening approaches or extends into the projection of the lintel plate; that is, relatively large air guide gaps arranged continuously from top to bottom are formed on the left and right sides of the guide backplate, respectively, so as to provide a timely discharge of relatively light small molecule gases accumulated in the left and right corner spaces of the upper or middle part of the cabinet cavity into the exhaust duct. The invention relates to a flow channel, and is also beneficial to reducing the resistance of air flow and the formation of vortices, and improving the air flow speed; when the fume hood is configured with an inhalation flow as the control air flow and a pressure gradient that gradually increases from bottom to top is formed in the inner cavity of the hood, there will be a certain inhalation speed gradient between the highest point and the lowest point of the gradually expanding air opening, and the shape change of the gradually expanding air opening is utilized, that is, a geometric shape that gradually increases from the bottom to the top, which is beneficial to forming a larger suction force at the upper part of the gradually expanding air opening relative to the lower part, so that more relatively light small molecule gases that drift upward and accumulate in the left and right corner spaces of the upper or middle part of the inner cavity of the hood can be sucked, and the formation of vortices can be further reduced.

2. The fume hood equipped with a through-air opening according to claim 1, characterized in that: The guide back plate has a narrowing plate portion, and both side edges of the narrowing plate portion gradually narrow towards each other from bottom to top in an inclined manner. The left cavity side wall and the right cavity side wall respectively have upright wall portions arranged corresponding to the narrowing plate portion and in an upright shape. The gradually expanding air passage openings arranged on the left and right sides are respectively formed between the left and right side edges of the narrowing plate portion and the upright wall portions of the left cavity side wall and the right cavity side wall.

3. The fume hood equipped with a through-air opening according to claim 1, characterized in that: The left and right cavity side walls respectively have a recessed wall portion, and the recessed wall portion is in a shape that is gradually recessed outward from bottom to top, and the guide back plate has a vertical plate portion arranged corresponding to the recessed wall portion and with vertical sides respectively, and the gradually expanding air openings arranged on the left and right are respectively formed between the recessed wall portions of the left and right cavity side walls and the two side sides of the vertical plate portion.

4. A fume hood equipped with a wind opening according to claim 1, 2 or 3, characterized in that: Vertical columns are respectively arranged on the left and right sides of the operation window, and the left and right vertical columns are distributed and connected to the left cavity side wall and the right cavity side wall. The left and right vertical columns are hollow and have air supply passages formed therein. The left and right vertical columns respectively include rear column walls facing the rear of the cabinet cavity, and inner air outlets arranged in the up and down directions are arranged on the rear column walls. The highest horizontal height of the inner air outlet is lower than the highest horizontal height of the gradually expanding air opening. The inner air outlet is connected to the air supply passage, and the inner air outlet is used to supply air to the rear direction of the cabinet cavity.

5. The fume hood equipped with a through-air opening according to claim 4, characterized in that: The inner air outlet is used to supply air to the inner cavity of the cabinet along a direction perpendicular to the plane of the operating window.

6. The fume hood equipped with a through-air opening according to claim 4, characterized in that: The inner air outlet is a plurality of through holes intermittently arranged in the up-down direction.

7. The fume hood equipped with a through-air opening according to claim 4, characterized in that: The inner air outlet is an air outlet slot that is continuously extended in the up-down direction.

8. The fume hood equipped with a through-air opening according to claim 4, characterized in that: The left cavity side wall and the right cavity side wall respectively include an inner plate and an outer plate, and the inner plate and the outer plate are arranged at intervals on the left and right to form an interlayer cavity therebetween, and a hollow wind box is arranged in the interlayer cavity, and an air inlet box hole is arranged on the top wall of the wind box, and an air outlet box hole is arranged on the front side wall; the cavity wall body also includes a cavity top wall, and an air inlet aisle is arranged on the cavity top wall, and the air inlet aisle is connected to the air inlet box hole, and the air outlet box hole is connected to the air supply channel.

9. The fume hood equipped with a through-air opening according to claim 8, characterized in that: The inner air outlet is close to the inner plate.

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