Laboratory ventilation cabinet with double air curtains

Abstract

The utility model relates to the technical field of fume cupboards, in particular to a double-air-curtain fume cupboard for a laboratory, which aims to solve the technical problems of high energy consumption and poor leakage prevention effect of an air supplement system in the prior art, and is mainly realized by the following technical scheme: the double-air-curtain fume cupboard for the laboratory comprises a cupboard body, a working cavity and an operation opening are formed in the cabinet body, a glass window slides outside the operation opening, a working cabinet is arranged below the cabinet body, the air supplementing device comprises an inner air supplementing part, an outer blocking part and an air supplementing chamber, the inner air supplementing part comprises an upper air supplementing structure and a lower air supplementing structure, the outer blocking part comprises an upper blocking structure and a lower blocking structure, and the air supplementing chamber is arranged in the cabinet body. The air exhaust device comprises an air exhaust chamber and a flow guide plate, air curtains are formed inside and outside the glass window through an inner air supplement piece and an outer blocking piece, dual protection is achieved during use, indoor air cannot enter the cabinet body, and waste gas in the cabinet is prevented from leaking; when the glass window is closed, only the inner air supplement piece is opened to reduce energy consumption.

Description

Technical Field

[0001] The utility model relates to the technical field of fume hoods, in particular to a double-air curtain laboratory fume hood. Background Art

[0002] As a local test site and local ventilation equipment in the laboratory, the fume hood plays a key role in controlling the local ventilation in the room. The function of the fume hood is to control the pollutants emitted from the cabinet and discharge them to the outside smoothly, blocking their diffusion path to the room, so that they will not escape into the room through the operation port of the fume hood, endangering the health and safety of the experimenters.

[0003] In the prior art, the fume hood includes an air supply duct and an exhaust duct. The exhaust duct extracts the waste gas generated by the experiment and a large amount of indoor constant temperature air. The air supply duct maintains the indoor pressure balance to replenish the air for the fume hood, and the new replenishment air needs to be reheated or cooled, which consumes a lot of energy. In addition, the fume hood does not have enough control over the diffusion of pollutants in the cabinet, which can easily cause it to diffuse to the operation port or even indoors, affecting the air quality of the laboratory; or in order to control the removal of harmful gases, the exhaust volume of the exhaust duct is increased, which affects the indoor ventilation, resulting in large temperature changes that affect the stability of the experiment. Utility Model Content

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defects of the air supply system in the prior art, that is, the air consumption is large and the anti-leakage effect is poor, thereby providing a double air curtain laboratory fume hood.

[0005] The above technical objectives of the utility model are achieved through the following technical solutions:

[0006] A double-air-curtain laboratory fume hood comprises a cabinet body, a working chamber is arranged in the cabinet body and an operation port is opened on the front side, a glass window is slidably arranged on the outer side of the operation port, sliding tracks are symmetrically arranged on the opposite sides of the glass window, the sliding tracks are arranged along the height direction of the cabinet body, a working cabinet is arranged below the cabinet body, and also comprises an air supply device and an air exhaust device, the air supply device comprises an inner air supply part, an outer barrier part and an air supply chamber, the inner air supply part is arranged in the working chamber on a side close to the glass window, the outer barrier part is arranged outside the glass window on a side away from the working chamber, the air supply chamber is arranged on the top of the cabinet body and is respectively connected with the inner air supply part and the outer barrier part through a plurality of air supply pipelines, the inner air supply part comprises an upper air supply structure and a lower air supply structure arranged relatively, and the outer barrier part comprises an upper barrier structure and a lower barrier structure arranged relatively; the exhaust device comprises an exhaust chamber and a guide plate, the exhaust chamber is arranged on the top of the cabinet body and is arranged in parallel with the air supply chamber, and the guide plate is arranged on a side of the working chamber away from the operation port.

[0007] By adopting the above technical solution, when the fume hood is in use, the exhaust device draws out the gas in the cabinet, and the air supply device introduces gas from the outside to perform air supply operation. The gas introduced by the air supply device is divided into two parts. The internal air supply part and the exhaust device constitute internal circulating wind and form an internal wind curtain to avoid gas leakage and pollution. The external barrier part blows air downward through the upper barrier structure and blows air upward through the lower barrier structure to form an outer wind curtain. The double wind curtain protection ensures the fume hood's leakage blocking effect and isolates the air exchange inside and outside the cabinet, reduces the heat exchange of indoor and outdoor gases, reduces temperature changes and can reduce energy consumption.

[0008] Furthermore, the upper air supply structure includes an upper air inlet plate and an upper side air plate which are integrally arranged, and the upper air inlet plate and the upper side air plates and the inner side surface of the working chamber form an inner air supply chamber, and the upper air inlet plate is arranged along the length direction of the operating port and fixed at the top of the cabinet, and the upper air inlet plate is also provided with an air supply groove along its length direction, and the upper side air plate is obliquely fixed in the working chamber, and a plurality of air supply holes are provided on the upper side air plate, and the bottom end of the upper side air plate is fixed to the upper air inlet plate and the top end is connected to the top of the working chamber, and the distance between the bottom end of the upper side air plate and the glass window is smaller than the distance between the top end of the upper side air plate and the glass window.

[0009] By adopting the above technical solution, the upper air supply structure guides the supplementary air flow into the working chamber, and the air flow is dispersed and evenly inclined into the working chamber through the upper wind plate, thereby reducing the situation where there is no air flow in the working chamber. The setting of the upper air inlet plate prevents the internal gas from scattering and overflowing, affecting the safety of the experimenter.

[0010] Furthermore, the lower air supply structure includes an integrally arranged lower air inlet plate and a lower side air plate. The lower air inlet plate is arranged along the length direction of the operating port and fixed at the bottom of the operating port. The lower air inlet plate is also provided with an air supply groove along its length direction. The lower side air plate is vertically fixed on the bottom of the working chamber. The top of the lower side air plate is fixed to the lower air inlet plate, and the lower side air plate is also provided with a plurality of air supply holes.

[0011] By adopting the above technical solution, the lower air supply structure supplies air to the working chamber through the air supply holes, and the airflows of the upper air inlet plate and the lower air inlet plate blow against each other to form an internal wind curtain in the glass window, thereby reducing the leakage of internal gas and solving the problem of air supply from the outside.

[0012] Furthermore, the upper barrier structure includes a front upper air cavity and a wind shield plate, the front upper air cavity is arranged at the top of the front side surface of the cabinet and is connected with the air supply chamber through the air supply duct, a wind curtain groove begins to be formed at the bottom of the front upper air cavity, a wind shield plate is slidably provided at the bottom of the front upper air cavity, the wind shield plate is arranged along the length direction of the front upper air cavity and is slidably provided along the width direction of the front upper air cavity; the lower barrier structure includes a front lower air cavity and a support plate, the front lower air cavity is arranged at the bottom part of the front side surface of the cabinet and is connected with the air supply chamber through the air supply duct, a wind curtain groove is opened at the top of the front lower air cavity, and the support plate is arranged at the bottom of the front lower air cavity and is fixed to the side wall of the cabinet.

[0013] By adopting the above technical solution, the upper barrier structure and the lower barrier structure are arranged relative to each other to form an external wind curtain outside the glass window, further reducing the leakage of internal gas and solving the problem of external air supply; the wind shield can adjust the air volume of the upper wind curtain slot; the support plate provides support for the front lower air cavity to ensure structural stability.

[0014] Furthermore, the upper blocking structure is also connected to an adjustment structure, and the adjustment structure is arranged at both ends of the wind shield. The adjustment structure on each side includes a follower rack, a driving gear, a plurality of driven gears meshing in sequence and an adjustment rack, the follower rack is fixed at both ends of the glass window and arranged along the height direction of the glass window, the follower rack is meshed with the driving gear, the driven gear is meshed and arranged above the driving gear, the driven gear has a diameter larger than that of the driving gear, the adjustment rack is meshed and arranged above the driven gear, the adjustment rack is vertically fixed to the side of the wind shield close to the glass window, the rotating axes of the driving gear and the driven gear are parallel and arranged along the length direction of the wind shield, and the movement direction of the follower rack is perpendicular to the movement direction of the adjustment rack.

[0015] By adopting the above technical solution, when the glass window is opened, the follower rack moves upward, driving the driving gear to rotate. Since the driving gear is meshed with the driven gear and the diameter of the driven gear is larger than the diameter of the driving gear, the driven gear is controlled to drive the adjustment rack to move with a small movement amplitude, so that the position of the wind shield can be adjusted slightly to control the air output of the upper blocking structure. When the glass window is pushed to the highest limit, the wind shield does not cover the wind curtain slot above, and the air output is maximum.

[0016] Furthermore, a control valve is provided on the air supply pipeline connecting the air supply chamber with the upper blocking structure and the lower blocking structure, and a contact switch is also provided on the upper surface of the front lower air cavity, and the contact switch is connected to the control valve signal control.

[0017] By adopting the above technical solution, when the glass window is closed, the bottom of the glass window contacts the contact switch to close the control valve. At this time, no air is supplied to the outside and no outer wind curtain is formed; the glass window moves upward, the limitation of the contact switch is released, the control valve is started, and air is supplied to the outside to form an outer wind curtain, thereby realizing double wind curtain protection.

[0018] Furthermore, an exhaust port is provided at the top of the cabinet corresponding to the exhaust chamber, the bottom area of ​​the exhaust chamber is larger than the exhaust port area, an exhaust port is also provided on the inner wall of the bottom of the cabinet, and the exhaust port is arranged on a side of the working chamber away from the operation port, and the exhaust port is connected to the exhaust chamber through an exhaust duct.

[0019] By adopting the above technical solution, the exhaust port sucks the gas passing through the guide plate, and the suction port directly sucks the internal gas, which can reduce the overflow of toxic and harmful gases.

[0020] Furthermore, a gap is left between the bottom of the guide plate and the inner bottom surface of the working chamber, and the guide plate includes an integrally arranged oblique guide and a straight guide, and the straight guide is fixed to the inner wall of the working chamber away from the operation port by bolts, and a gap is left between the straight guide and the inner wall of the working chamber, and a plurality of exhaust holes are provided on the straight guide, and the oblique guide is fixed to the top of the straight guide, and the top of the oblique guide is fixed to the inner top surface of the working chamber and the bottom is fixed to the top of the straight guide, and the distance between the top of the oblique guide and the operation port is smaller than the distance between the bottom and the operation port.

[0021] By adopting the above technical solution, the guide plate is set to facilitate the discharge of internal gas, and can smoothly suck the gas inside the cabinet, reduce the generation of gas vortex and avoid excessive air ducts affecting the stability of the internal circulation.

[0022] In summary, the technical solution of the utility model has the following advantages:

[0023] 1. The double air curtain laboratory fume hood provided by the utility model, when the fume hood is in use, the inner air supply part and the exhaust device form an internal circulating wind and form an internal air curtain to prevent gas leakage and pollution, the outer barrier part blows air downward through the upper barrier structure and blows air upward through the lower barrier structure to form an outer air curtain, the double air curtain protection ensures the fume hood's leakage prevention effect and isolates the air exchange inside and outside the cabinet, reduces the heat exchange of indoor and outdoor gases, reduces temperature changes and can reduce energy consumption.

[0024] 2. In the double-wind curtain laboratory fume hood provided by the utility model, the upward movement of the glass window can drive the wind shield to move, so that the position of the wind shield can be slightly adjusted to control the air output of the upper barrier structure. When the glass window is pushed to the highest limit, the wind shield does not cover the upper wind curtain slot, and the air output is maximum. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the overall structure of a double air curtain laboratory fume hood provided in one embodiment of the utility model;

[0027] Figure 2 A schematic diagram of a partial explosion structure of a cabinet provided in one embodiment of the utility model;

[0028] Figure 3 The present invention is a schematic diagram of a cross-sectional structure of a cabinet provided in one embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 1. Cabinet; 11. Working chamber; 12. Operation port; 13. Exhaust port; 14. Air extraction port; 2. Glass window; 21. Sliding track; 3. Working cabinet; 4. Air supply device; 5. Internal air supply component; 51. Upper air supply structure; 511. Upper air inlet plate; 512. Upper side air plate; 513. Internal air supply cavity; 52. Lower air supply structure; 521. Lower air inlet plate; 522. Lower side air plate; 53. Air supply slot; 54. Air supply hole; 6. External blocking component; 61. Upper blocking structure; 611. Front upper air cavity; 612 , wind shield; 613, adjustment structure; 6131, follower rack; 6132, driving gear; 6133, driven gear; 6134, adjustment rack; 62, lower blocking structure; 621, front lower air cavity; 6211, contact switch; 622, support plate; 63, wind curtain slot; 7, make-up air chamber; 71, make-up air pipeline; 711, control valve; 8, exhaust device; 81, exhaust chamber; 811, exhaust pipeline; 82, guide plate; 821, oblique guide; 822, straight guide; 8221, exhaust hole. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] A double air curtain laboratory fume hood, such as Figure 1 and Figure 3As shown, it includes a cabinet 1, a working chamber 11 is arranged in the cabinet 1, and an operation port 12 is opened on the front side, a glass window 2 is slidably arranged outside the operation port 12, and sliding tracks 21 are symmetrically arranged on the opposite sides of the glass window 2, and the sliding tracks 21 are arranged along the height direction of the cabinet 1, and a working cabinet 3 is arranged below the cabinet 1. It also includes an air supply device 4 and an air exhaust device 8, and the air supply device 4 includes an inner air supply member 5, an outer barrier member 6 and an air supply chamber 7, the inner air supply member 5 is arranged on the side of the working chamber 11 close to the glass window 2, and the outer barrier member 6 is arranged on the side of the glass window 2 away from the working chamber 11, and the air supply chamber 7 is arranged on the top of the cabinet 1 and is connected to the inner air supply member 5 and the outer barrier member 6 through a plurality of air supply pipelines 71, respectively, the inner air supply member 5 includes an upper air supply structure 51 and a lower air supply structure 52 arranged oppositely, and the outer barrier member 6 includes an upper barrier structure 61 and a lower barrier structure 62 arranged oppositely. The exhaust device 8 includes an exhaust chamber 81 and a guide plate 82. The exhaust chamber 81 is arranged on the top of the cabinet 1 and is arranged in parallel with the air supply chamber 7. The guide plate 82 is arranged on the side of the working chamber 11 away from the operation port 12. When the fume hood is in use, the exhaust device 8 extracts the gas in the cabinet 1, and the air supply device 4 introduces gas from the outside to perform air supply operation. The gas introduced by the air supply device 4 is divided into two parts. The internal air supply member 5 and the exhaust device 8 form an internal circulation wind and form an internal wind curtain to prevent gas leakage and pollution. The external barrier member 6 blows air downward through the upper barrier structure 61 and blows air upward through the lower barrier structure 62 to form an outer wind curtain. The double wind curtain protection ensures the effect of the fume hood in blocking leakage and isolates the air exchange between the inside and outside of the cabinet 1, reduces the heat exchange of indoor and outdoor gases, reduces temperature changes and can reduce energy consumption.

[0033] like Figure 3 As shown, the upper air supply structure 51 includes an upper air inlet plate 511 and an upper side air plate 512 which are integrally arranged. The upper air inlet plate 511 and the upper side air plate 512 form an inner air supply cavity 513 with the inner side surface of the working chamber 11. The upper air inlet plate 511 is arranged along the length direction of the operation port 12 and fixed at the upper part of the cabinet 1. The upper air inlet plate 511 is also provided with an air supply groove 53 along its length direction. The upper side air plate 512 is tilted and fixed in the working chamber 11. A plurality of air supply holes 54 are provided on the upper side air plate 512. The bottom end of the upper side air plate 512 is fixed to the upper air inlet plate 511 and the top end is connected to the top of the working chamber 11. The distance between the bottom end of the upper side air plate 512 and the glass window 2 is smaller than the distance between the top end of the upper side air plate 512 and the glass window 2. The upper air supply structure 51 guides the supplementary air flow into the working chamber 11, and the upper air plate 512 makes the air flow dispersed and evenly inclined into the working chamber 11, thereby reducing the situation where there is no air flow in the working chamber 11. The setting of the upper air inlet plate 511 prevents the internal gas from scattering and overflowing, affecting the safety of the experimenter.

[0034] The lower air supply structure 52 includes an integrally arranged lower air inlet plate 521 and a lower side air plate 522. The lower air inlet plate 521 is arranged along the length direction of the operation port 12 and fixed at the bottom of the operation port 12. The lower air inlet plate 521 also has an air supply groove 53 along its length direction. The lower side air plate 522 is vertically fixed to the bottom of the working chamber 11. The top of the lower side air plate 522 is fixed to the lower air inlet plate 521. The lower side air plate 522 also has a plurality of air supply holes 54. The lower air supply structure 52 supplies air to the working chamber 11 through the air supply holes 54. The upper air inlet plate 511 and the lower air inlet plate 521 blow against each other to form an internal wind curtain in the glass window 2, thereby reducing the leakage of internal gas and solving the problem of air supply from the outside.

[0035] like Figure 3 As shown, an exhaust port 13 is provided at the top of the cabinet 1 corresponding to the exhaust chamber 81, and the bottom area of ​​the exhaust chamber 81 is larger than the area of ​​the exhaust port 13. An air suction port 14 is also provided on the inner wall of the bottom of the cabinet 1. The air suction port 14 is arranged on a side of the working chamber 11 away from the operation port 12, and the air suction port 14 is connected to the exhaust chamber 81 through the exhaust pipe 811. A filter block or an adsorption block can be provided at the air suction port 14, and the place is cleaned and replaced after multiple tests. The exhaust port 13 sucks the gas passing through the guide plate 82, and the air suction port 14 directly sucks the internal gas, which can reduce the overflow of toxic and harmful gases.

[0036] like Figure 3 As shown, there is a gap between the bottom of the guide plate 82 and the inner bottom surface of the working chamber 11, and the guide plate 82 includes an integrally arranged oblique guide 821 and a straight guide 822. The straight guide 822 is fixed to the inner wall of the working chamber 11 away from the operation port 12 by bolts, and there is a gap between the straight guide 822 and the inner wall of the working chamber 11. A plurality of exhaust holes 8221 are provided near the bottom of the straight guide 822. The oblique guide 821 is fixed to the top of the straight guide 822. The top of the oblique guide 821 is fixed to the inner top surface of the working chamber 11 and the bottom is fixed to the top of the straight guide 822. The distance between the top of the oblique guide 821 and the operation port 12 is smaller than the distance between the bottom and the operation port 12. The guide plate 82 is provided to facilitate the extraction of internal gas, and can smoothly draw gas from the cabinet 1, reduce the generation of gas vortexes, and avoid excessive air ducts affecting the stability of the internal circulation.

[0037] like Figure 2 and Figure 3As shown, the upper barrier structure 61 includes a front upper air cavity 611 and a wind shield 612. The front upper air cavity 611 is arranged at the top of the front side of the cabinet 1 and is connected to the air supply chamber 7 through the air supply pipeline 71. A wind curtain groove 63 is provided at the bottom of the front upper air cavity 611. A wind shield 612 is slidably provided at the bottom of the front upper air cavity 611. The wind shield 612 is arranged along the length direction of the front upper air cavity 611 and is slidably provided along the width direction of the front upper air cavity 611. The upper barrier structure 61 and the lower barrier structure 62 are arranged relative to each other to form an external wind curtain outside the glass window 2, further reducing the leakage of internal gas and solving the problem of air supply from the outside.

[0038] like Figure 2 and Figure 3 As shown, the upper barrier structure 61 is also connected to an adjustment structure 613, which is arranged at both ends of the wind shield 612. The adjustment structure 613 on each side includes a follower rack 6131, a driving gear 6132, a plurality of driven gears 6133 meshed in sequence, and an adjustment rack 6134. The follower rack 6131 is fixed at both ends of the glass window 2 and arranged along the height direction of the glass window 2. The follower rack 6131 meshes with the driving gear 6132, and the driven gear 6133 meshes with the adjusting rack 6134. It is arranged above the driving gear 6132, the diameter of the driven gear 6133 is larger than that of the driving gear 6132, the adjusting rack 6134 is meshingly arranged above the driven gear 6133, the adjusting rack 6134 is vertically fixed to the side of the wind shield 612 close to the glass window 2, the rotating axes of the driving gear 6132 and the driven gear 6133 are parallel and arranged along the length direction of the wind shield 612, and the movement direction of the driven rack 6131 is perpendicular to the movement direction of the adjusting rack 6134. When the glass window 2 is opened, the follower rack 6131 moves upward, driving the driving gear 6132 to rotate. Since the driving gear 6132 is meshed with the driven gear 6133 and the diameter of the driven gear 6133 is larger than that of the driving gear 6132, the driven gear 6133 is controlled to drive the adjustment rack 6134 to move with a small movement amplitude, so that the position of the wind shield 612 can be adjusted slightly to control the air flow of the upper blocking structure 61. When the glass window 2 is pushed to the highest limit, the wind shield 612 does not cover the wind curtain slot 63 above, and the air flow is maximum. Since the glass window 2 has a long upward sliding distance and the wind shield 612 has a short sliding distance, multiple driven gears 6133 are set according to the adjustment situation and the height of the cabinet 1 to form a reduction gear set, so as to facilitate the conversion of distance adjustment.

[0039] like Figure 2 and Figure 3As shown, the air supply pipe 71 connecting the air supply chamber 7 with the upper blocking structure 61 and the lower blocking structure 62 is provided with a control valve 711, and the upper surface of the front lower air chamber 621 is also provided with a contact switch 6211, and the contact switch 6211 is connected with the control valve 711 by signal control. When the glass window 2 is closed, the bottom of the glass window 2 contacts the contact switch 6211 to close the control valve 711, at which time the outside is not supplied with air, and no outside wind curtain is formed; when the glass window 2 moves upward, the limitation of the contact switch 6211 is released, the control valve 711 is started, and the outside is supplied with air, forming an outside wind curtain, realizing double wind curtain protection.

[0040] like Figure 2 and Figure 3 As shown, the lower blocking structure 62 includes a front lower air chamber 621 and a support plate 622. The front lower air chamber 621 is arranged at the bottom of the front side of the cabinet 1 and is connected to the air supply chamber 7 through the air supply pipe 71. The top of the front lower air chamber 621 is provided with an air curtain groove 63. The support plate 622 is arranged at the bottom of the front lower air chamber 621 and is fixed to the side wall of the cabinet 1. The support plate 622 provides support for the front lower air chamber 621 to ensure the stability of the structure.

[0041] The working principle and use method of the double-wind curtain laboratory fume hood: when the glass window 2 of the fume hood is closed, the contact switch 6211 is closed, and only the internal air supply structure and the exhaust device 8 can work, and the internal air supply part 5 and the exhaust device 8 form an internal circulation wind; when the fume hood is in use, the glass window 2 moves up. In this process, it drives the follower rack 6131 to move up, and controls the driven gear 6133 to drive the adjustment rack 6134 to move with a small movement amplitude, adjust the position of the wind shield plate 612, and control the air output of the upper barrier structure 61. At this time, the internal air supply part 5 and the exhaust device 8 form an internal circulation wind and form an internal wind curtain to avoid gas leakage pollution. The external barrier part 6 blows air downward through the upper barrier structure 61 and upward through the lower barrier structure 62 to form an outer wind curtain. The double wind curtain protection ensures the effect of the fume hood in blocking leakage and isolates the air exchange inside and outside the cabinet 1.

[0042] The above description shows and describes the preferred embodiments of the utility model. As mentioned above, it should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the utility model concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A double air curtain laboratory fume hood, comprising a cabinet (1), wherein a working chamber (11) is arranged in the cabinet (1) and an operation opening (12) is opened on the front side, a glass window (2) is slidably arranged outside the operation opening (12), and sliding tracks (21) are symmetrically arranged on opposite sides of the glass window (2), and the sliding tracks (21) are arranged along the height direction of the cabinet (1), and a working cabinet (3) is arranged below the cabinet (1), characterized in that: The cabinet further comprises an air supply device (4) and an air exhaust device (8), wherein the air supply device (4) comprises an inner air supply member (5), an outer barrier member (6) and an air supply chamber (7), wherein the inner air supply member (5) is arranged on a side of the working chamber (11) close to the glass window (2), and the outer barrier member (6) is arranged on a side of the working chamber (11) outside the glass window (2) away from the working chamber (11), and the air supply chamber (7) is arranged on the top of the cabinet (1) and is respectively connected to the inner air supply member (5) and the outer barrier member (6) through a plurality of air supply pipelines (71). ), the internal air supply component (5) includes an upper air supply structure (51) and a lower air supply structure (52) that are arranged opposite to each other, and the external blocking component (6) includes an upper blocking structure (61) and a lower blocking structure (62) that are arranged opposite to each other; the exhaust device (8) includes an exhaust chamber (81) and a guide plate (82), the exhaust chamber (81) is arranged at the top of the cabinet (1) and is arranged in parallel with the air supply chamber (7), and the guide plate (82) is arranged on a side of the working chamber (11) away from the operation port (12).

2. A double air curtain laboratory fume hood according to claim 1, characterized in that: The upper air supply structure (51) comprises an upper air inlet plate (511) and an upper side air plate (512) which are integrally arranged. The upper air inlet plate (511) and the upper side air plate (512) together with the inner side of the working chamber (11) form an inner air supply cavity (513). The upper air inlet plate (511) is arranged along the length direction of the operation port (12) and is fixed at the upper part of the cabinet (1). The upper air inlet plate (511) is also provided with an air supply groove (513) along its length direction. 3), the upper wind plate (512) is tilted and fixed in the working chamber (11), a plurality of air supply holes (54) are provided on the upper wind plate (512), the bottom end of the upper wind plate (512) is fixed to the upper air inlet plate (511) and the top end is connected to the top of the working chamber (11), and the distance between the bottom end of the upper wind plate (512) and the glass window (2) is smaller than the distance between the top end of the upper wind plate (512) and the glass window (2).

3. A double air curtain laboratory fume hood according to claim 2, characterized in that: The lower air supply structure (52) comprises an integrally arranged lower air inlet plate (521) and a lower side air plate (522); the lower air inlet plate (521) is arranged along the length direction of the operation port (12) and fixed at the bottom of the operation port (12); the lower air inlet plate (521) is also provided with an air supply groove (53) along its length direction; the lower side air plate (522) is vertically fixed to the bottom of the working chamber (11); the top of the lower side air plate (522) is fixed to the lower air inlet plate (521); and the lower side air plate (522) is also provided with a plurality of air supply holes (54).

4. A double air curtain laboratory fume hood according to claim 1, characterized in that: The upper blocking structure (61) comprises a front upper air cavity (611) and a wind shield (612); the front upper air cavity (611) is arranged at the top of the front side of the cabinet (1) and is connected to the air supply chamber (7) through an air supply pipeline (71); an air curtain groove (63) is provided at the bottom of the front upper air cavity (611); a wind shield (612) is slidably provided at the bottom of the front upper air cavity (611); the wind shield (612) is arranged along the length direction of the front upper air cavity (611) and along the The front upper air chamber (611) is slidably arranged in the width direction; the lower blocking structure (62) comprises a front lower air chamber (621) and a support plate (622); the front lower air chamber (621) is arranged at the bottom of the front side surface of the cabinet (1) and is connected to the air supply chamber (7) through an air supply pipeline (71); an air curtain groove (63) is opened at the top of the front lower air chamber (621); and the support plate (622) is arranged at the bottom of the front lower air chamber (621) and is fixed to the side wall of the cabinet (1).

5. A double air curtain laboratory fume hood according to claim 4, characterized in that: The upper blocking structure (61) is also connected to an adjustment structure (613), and the adjustment structure (613) is arranged at both ends of the wind shield (612). The adjustment structure (613) on each side includes a follower rack (6131), a driving gear (6132), a plurality of sequentially meshed driven gears (6133) and an adjustment rack (6134). The follower rack (6131) is fixed to both ends of the glass window (2) and is arranged along the height direction of the glass window (2). The follower rack (6131) is meshed with the driving gear (6132). The driven gear (6133) The meshing device is arranged above the driving gear (6132); the diameter of the driven gear (6133) is larger than that of the driving gear (6132); the adjusting rack (6134) is arranged above the driven gear (6133); the adjusting rack (6134) is vertically fixed to the side of the wind shield (612) close to the glass window (2); the rotating axes of the driving gear (6132) and the driven gear (6133) are parallel and arranged along the length direction of the wind shield (612); the movement direction of the follower rack (6131) is perpendicular to the movement direction of the adjusting rack (6134).

6. A double air curtain laboratory fume hood according to claim 4, characterized in that: A control valve (711) is provided on the air supply pipe (71) connecting the air supply chamber (7) with the upper barrier structure (61) and the lower barrier structure (62), and a contact switch (6211) is also provided on the upper surface of the front lower air cavity (621), and the contact switch (6211) is connected to the control valve (711) by signal control.

7. A double air curtain laboratory fume hood according to claim 1, characterized in that: An exhaust port (13) is provided at the top of the cabinet (1) corresponding to the exhaust chamber (81); the bottom area of ​​the exhaust chamber (81) is larger than the area of ​​the exhaust port (13); an air suction port (14) is also provided on the inner side wall of the bottom of the cabinet (1); the air suction port (14) is arranged on a side of the working chamber (11) away from the operation port (12); and the air suction port (14) is connected to the exhaust chamber (81) via an exhaust pipe (811).

8. A double air curtain laboratory fume hood according to claim 7, characterized in that: A gap is left between the bottom of the guide plate (82) and the inner bottom surface of the working chamber (11); the guide plate (82) comprises an integrally arranged oblique guide (821) and a straight guide (822); the straight guide (822) is fixed to the inner wall of the working chamber (11) away from the operation port (12) by means of bolts; a gap is left between the straight guide (822) and the inner wall of the working chamber (11); a plurality of exhaust holes (8221) are provided on the straight guide (822); the oblique guide (821) is fixed to the top of the straight guide (822); the top of the oblique guide (821) is fixed to the inner top surface of the working chamber (11) and the bottom is fixed to the top of the straight guide (822); the distance between the top of the oblique guide (821) and the operation port (12) is smaller than the distance between the bottom and the operation port (12).

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