Automatic negative pressure maintaining device for biological safety cabinet

Abstract

The present invention provides an automatic negative pressure maintenance device for a biosafety cabinet, relating to the field of biosafety cabinets. The device comprises a biosafety cabinet body, an automatic negative pressure maintenance unit disposed at the upper end of the cabinet body, and an air duct communicating with the cabinet body. The air duct and the cabinet body are connected via a vent, a duct check valve disposed at the vent, and a fan and an air filter disposed within the air duct. The device is capable of automatically adjusting the filtration efficiency of a foldable filter according to the air flow velocity in the air duct housing.

Description

Technical Field

[0001] The present invention relates to the field of biological safety cabinets, and in particular to an automatic negative pressure maintaining device for a biological safety cabinet. Background Art

[0002] A biological safety cabinet is a special protective equipment used in biological laboratories. It prevents the operator from making mistakes during the experiment, which may lead to the aerosol release of certain dangerous or unknown biological particles, and protects the health and safety of the operator.

[0003] The working principle of the biological safety cabinet is mainly to suck the air inside the cabinet outward to maintain a negative pressure inside the cabinet and protect the staff through vertical airflow; the outside air enters the safety cabinet after being filtered to avoid contamination of the processed samples; the air inside the cabinet also needs to be filtered before being discharged into the atmosphere to protect the environment.

[0004] In the prior art, gas is filtered by setting up two upper and lower filter elements. However, in actual use, the flow rate of the gas to be filtered varies greatly in different usage scenarios. In the prior art, the projected area of the filter and the flowing airflow is fixed, that is, the filtration efficiency is relatively fixed. As the filtration time increases, the filter will become dirtier, the wind resistance will become greater, and the filtration efficiency will become lower and lower; the negative pressure inside the biosafety cabinet cannot be maintained stably. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an automatic negative pressure maintaining device for a biological safety cabinet, including a cabinet body of the biological safety cabinet, and is characterized in that an automatic negative pressure maintaining part is provided at the upper end of the cabinet body, the automatic negative pressure maintaining part has an air duct connected to the cabinet body, the air duct and the cabinet body are connected through an opened ventilation port, an air duct one-way valve is provided at the ventilation port, and a fan and an air filter are provided in the air duct.

[0006] An ultraviolet sterilization lamp is also provided in the air duct, and is arranged upstream in the ventilation direction of the air duct.

[0007] The air filter is a high efficiency air filter HEPA, which is arranged downstream in the ventilation direction of the air duct.

[0008] The air filter includes an air duct shell installed on the left and right sides of the air duct, and a foldable filter is fixedly installed on the left and right sides of the inner wall of the air duct shell. The foldable filter is formed by connecting multiple W-shaped filter screens. The connection between two adjacent W-shaped filter screens is provided with a V-shaped connecting end, and the inner side of the V-shaped connecting end on the left and right sides is provided with a wedge block, and the wedge block drives the V-shaped connecting end on the left and right sides to move left and right.

[0009] The lower ends of the outer walls of the two wedge blocks are fixedly installed with sliding blocks 1, and the lower ends of the left and right inner walls of the air duct shell are fixedly installed with connecting blocks, and the opposite sides of the inner walls of the left and right connecting blocks are fixedly installed with slide rail frames, and the two sliding blocks 1 are slidably connected to the inner walls of the slide rail frame, and the inner walls of the left and right connecting blocks are rotatably connected with screws located at the rear end of the slide rail frame, and the thread directions of the left and right sides of the screw are opposite, and the outer walls of the screw are symmetrically threaded with sliding blocks 2 on the left and right sides, and the lower ends of the outer walls of the two sliding blocks 2 are fixedly installed with N-type connecting rods, and the front end of each N-type connecting rod is fixedly connected to the lower end of the outer wall of the sliding block 1 on the corresponding side.

[0010] The axle up and down groove at two ends embeds respectively in two guide rails up and down of being made up of the groove on the attachment piece, and the tooth on the attachment piece is meshed with tooth on upper sprocket wheel, the lower sprocket. The tooth on the attachment piece is meshed with tooth on upper sprocket.

[0011] Protective plates are symmetrically fixedly installed on the outer wall of the screw and on the left and right sides of the bevel gear; a winding drum is fixedly installed on the front section of the outer wall of the rotating shaft, an elastic rope is wound around the inner wall of the winding drum, and a fixing rod is fixedly installed on the end of the elastic rope away from the winding drum, and the front end of the outer wall of the fixing rod is fixedly connected to the rear end of the outer wall of the air duct shell.

[0012] Connecting plates are fixedly installed on the left and right sides of the outer wall of the foldable filter, and the connecting plates are fixedly connected to the inner wall of the air duct housing.

[0013] A transparent sealing plate is provided on the front of the cabinet, which includes an upper sealing plate and a lower sealing plate. The upper sealing plate is fixed and the lower sealing plate is openable and closable. The lower sealing plate is opened and closed by sliding up and down along the guide rails on both sides. A rubber sealing strip is provided at the opening and closing position of the lower edge of the lower sealing plate and the cabinet. The rubber sealing strip has a U-shaped groove, and the lower edge of the lower sealing plate can be inserted into the U-shaped groove to achieve sealing.

[0014] The airflow filtration method based on the airflow filtration device of the biosafety cabinet comprises the following specific steps:

[0015] S1, a flow of air enters the air duct housing, and the flow of air drives the fan blades to rotate;

[0016] S2, when the fan blades rotate, they can drive the rotating shaft 1, the bevel gear 2, the bevel gear 2, the rotating shaft 2, the bevel gear 3, the bevel gear 3, the bevel gear 4 and the rotating shaft 3 to rotate. When the bevel gear 4 rotates, it can drive the bevel gear 1 to rotate, and finally make the bevel gear 1 rotate, so that the screw rotates, and the screw drives the two sliding blocks 2 thereon to perform relative motion;

[0017] S3, when the two sliding blocks 2 move, the two sliding blocks 1 can be driven by the N-shaped connecting rod to slide on the inner wall of the slide rail frame, so that the two wedge blocks move relative to each other;

[0018] S4. The fan blades can drive the winding drum to rotate when rotating, and the winding drum can wind and stretch the elastic rope when rotating. When the air flow velocity decreases or there is no air flow, the wound and stretched elastic rope will drive the winding drum to rotate in the opposite direction, so that the opening angle of the V-shaped connecting end is reduced, and the foldable filter is folded up.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) When the present invention is used, the wedge-shaped blocks on the left and right sides can drive the V-shaped connecting ends in contact with them to move relative to each other, so that the angle of the V-shaped connecting ends changes, thereby expanding or contracting each W-shaped filter, and then changing the projected area of the air flow flowing in each W-shaped filter and the air duct housing, thereby adjusting the filtering efficiency of the foldable filter.

[0021] (2) When the present invention is used, when the flow air in the air duct housing passes through, it can drive the fan blades to rotate, so that the device can use the flow air in the air duct housing as a power to drive the two wedge blocks to move relative to each other, so that each W-shaped filter can be automatically unfolded when there is flow air passing through the device.

[0022] (3) When the present invention is used, the airflow velocity in the air duct housing will cause the fan blades to rotate at different angles to overcome the elastic potential energy of the elastic cord. The greater the airflow velocity, the greater the fan blade rotation angle, which increases the opening angle of the V-shaped connection end, making the expansion area of each W-shaped filter larger, and increasing the filtration efficiency of the foldable filter. When the airflow velocity decreases or there is no airflow, the wound and stretched elastic cord will drive the winding drum to rotate in the opposite direction, reducing the opening angle of the V-shaped connection end and closing the foldable filter. This allows the device to automatically adjust the filtration efficiency of the foldable filter according to the airflow velocity in the air duct housing. This maintains the stability of the filter ventilation volume, which is conducive to maintaining the negative pressure of the biological safety cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0024] Figure 2 Schematic diagram of the three-dimensional structure of the air filter;

[0025] Figure 3 Schematic diagram of the rear structure of the air filter;

[0026] Figure 4 It is a side view of the air filter;

[0027] Figure 5 It is a side view of the internal structure of the air filter housing;

[0028] Figure 6 This is an enlarged view of the structure at point A in the side view of the air filter;

[0029] Figure 7 This is a schematic diagram of the front structure of the air filter slide frame;

[0030] Figure 8 This is a schematic diagram of the rear structure of the air filter slide frame;

[0031] Figure 9 This is a structural diagram of the air filter winding reel.

[0032] Reference numerals: 1, air duct; 2, upper sealing plate; 3, lower sealing plate; 4, cabinet; 5, rubber sealing strip; 10, air filter; 100, air duct housing; 110, foldable filter; 111, W-shaped filter; 120, connecting plate; 200, V-shaped connecting end; 210, wedge block; 300, slide rail frame; 310, sliding block 1; 400, connecting block; 410, screw; 420, sliding block 2; 43 0. N-type connecting rod; 500. Bevel gear one; 510. Protective plate; 600. Connecting frame one; 601. Rotating shaft three; 610. Bevel gear four; 700. Support rod; 710. Rotating shaft one; 720. Fan blade; 730. Bevel gear two; 800. Connecting frame two; 810. Fixed block; 820. Rotating shaft two; 830. Bevel gear three; 900. Winding reel; 910. Fixed rod; 920. Elastic rope. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments and drawings. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without making any creative work are all within the scope of protection of the present invention.

[0034] Specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0035] Example 1

[0036] like Figure 1-6 As shown, a kind of automatic negative pressure maintaining device of biological safety cabinet comprises the cabinet 4 of biological safety cabinet, the upper end of cabinet 4 is provided with automatic negative pressure maintaining part, described automatic negative pressure maintaining part has air duct 1 communicated with cabinet 4, air duct 1 and cabinet 4 are communicated through ventilating port, ventilating port is provided with air duct one-way valve, air duct 1 is provided with fan and air filter 10; The front of cabinet 4 is provided with transparent sealing plate, transparent sealing plate comprises upper sealing plate 2 and lower sealing plate 3, upper sealing plate 2 is fixed, lower sealing plate 3 is openable and closable, the opening and closing mode of lower sealing plate 3 is to slide up and down along two side guide rails (being prior art, not shown in the figure, similar to the slide rails on both sides of drawer) and realize opening and closing, the opening and closing place of lower sealing plate 3 lower edge and cabinet 4 is provided with rubber sealing strip 5, rubber sealing strip 5 has U-shaped groove, and lower sealing plate 3 lower edge can be inserted into U-shaped groove and realize sealing. Transparent sealing plate can be made of transparent plastic paper material or transparent glass material.

[0037] An ultraviolet germicidal lamp is also provided in the air duct 1 , and is arranged upstream in the ventilation direction of the air duct 1 ; the air filter 10 adopts a high-efficiency air filter HEPA, and is arranged downstream in the ventilation direction of the air duct 1 .

[0038] The air filter 10 includes a duct housing 100 that is installed on the left and right sides of the duct 1. A foldable filter screen 110 is fixedly installed on the left and right sides of the inner wall of the duct housing 100. A connecting plate 120 is fixedly installed on the left and right sides of the outer wall of the foldable filter screen 110. The inner wall of the duct housing 100 and the foldable filter screen 110 are fixedly connected by the connecting plate 120. The foldable filter screen 110 is formed by connecting a plurality of W-shaped filter screens 111. A V-shaped connecting end 200 is provided at the connection between two adjacent W-shaped filter screens 111 on the left and right. A wedge block 210 is provided on the inner side of the V-shaped connecting end 200 on the left and right sides. The wedge block 210 and the inner side wall of the V-shaped connecting end 200 fit together, and the wedge block 210 drives the V-shaped connecting end 200 on the left and right sides to move left and right.

[0039] Among them: when the wedge blocks 210 on the left and right sides move relative to each other, they can drive the V-shaped connecting ends 200 in contact with them to move relative to each other, so that the angle of the V-shaped connecting ends 200 changes, thereby expanding or contracting each W-shaped filter 111, and then changing the projected area of the airflow flowing in each W-shaped filter 111 and the air duct housing 100, thereby adjusting the filtering efficiency of the foldable filter 110.

[0040] Example 2

[0041] Based on the first embodiment, the solution in the first embodiment is further detailed in combination with the following specific working methods, as described below:

[0042] As attached Figures 1-9 The figure shows an air flow filter device for a biological safety cabinet, wherein the lower ends of the outer walls of the two wedge-shaped blocks 210 are fixedly mounted with sliding blocks 1 310, the lower ends of the left and right inner walls of the air duct housing 100 are fixedly mounted with connecting blocks 400, and the opposite sides of the inner walls of the left and right connecting blocks 400 are fixedly mounted with slide rail frames 300, and the two sliding blocks 1 310 are slidably connected to the inner walls of the slide rail frames 300, and the inner walls of the left and right connecting blocks 400 are rotatably connected with screws 410 located at the rear end of the slide rail frames 300, and the threads on the left and right sides of the screws 410 are opposite, and the outer walls of the screws 410 are symmetrically threaded with sliding blocks 2 420, and the two The lower end of the outer wall of each sliding block 420 is fixedly installed with an n-type connecting rod 430, and the front end of each n-type connecting rod 430 is fixedly connected to the lower end of the outer wall of the sliding block 1 310 on the corresponding side. A bevel gear 500 is fixedly installed in the middle of the outer wall of the screw 410. A protective plate 510 is symmetrically fixedly installed on the outer wall of the screw 410 and located on the left and right sides of the bevel gear 500. A connecting frame 600 is fixedly installed on the inner wall of the left and right connecting blocks 400 and located at the rear end of the screw 410. The upper end of the outer wall of the connecting frame 600 is fixedly installed by a support rod 700, and the upper end of the outer wall of the support rod 700 is rotatably connected to a rotating shaft 710. The front section of the outer wall of the rotating shaft 710 passes through the rear side of the outer wall of the support rod 700 and is fixedly installed with a fan blade 720. The rear end of the outer wall of the fan blade 720 is fixedly installed with a bevel gear 2 730. The upper end of the outer wall of the connecting frame 600 is symmetrically fixed with the connecting frame 2 800 on both sides. The upper ends of the outer walls of the two connecting frames 800 are fixedly installed with a fixed block 810 at the same time. The fixed block 810 is internally connected to the rotating shaft 2 820 for rotation. The upper and lower ends of the outer wall of the rotating shaft 2 820 are fixedly installed with a bevel gear 3 830. The internal connection of the connecting frame 600 is connected to the rotating shaft 3 601. The front and rear ends of the outer wall of the rotating shaft 3 601 are fixedly installed. There is a bevel gear four 610, and the bevel gear four 610 on the front and rear sides are respectively meshed with the bevel gear one 500 and the bevel gear three 830. A winding drum 900 is fixedly installed on the front section of the outer wall of the rotating shaft one 710, and an elastic rope 920 is wound around the inner wall of the winding drum 900. The number of elastic ropes 920 can be changed according to the rated wind speed of the air duct shell 100 and the model of the fan blade 720. The elastic rope 920 can be an elastic rubber rope or a cow tendon rope. A fixing rod 910 is fixedly installed on the end of the elastic rope 920 away from the winding drum 900, and the front end of the outer wall of the fixing rod 910 is fixedly connected to the rear end of the outer wall of the air duct shell 100.

[0043] Among them: When the flow airflow in the air duct housing 100 passes through, it can drive the fan blade 720 to rotate. When the fan blade 720 rotates, it can drive the rotating shaft 1 710 and the bevel gear 2 730 to rotate, so that the bevel gear 2 730 drives the rotating shaft 2 820 and the bevel gear 3 830 to rotate, thereby making the bevel gear 3 830 drive the bevel gear 4 610 and the rotating shaft 3 601 to rotate. When the bevel gear 4 610 rotates, it can drive the bevel gear 1 500 to rotate, and finally make the bevel gear 1 500 rotate, so that the screw 4 10 rotates, the screw 410 drives the two sliding blocks 2 420 thereon to make relative motion, and can move away from or approach each other at the same time. At the same time, when the two sliding blocks 2 420 move, they can respectively drive the two sliding blocks 1 310 to slide on the inner wall of the slide rail frame 300 through the N-shaped connecting rod 430, so that the two wedge blocks 210 move relative to each other, so that the device can use the flow airflow in the air duct housing 100 as a driving force to drive the two wedge blocks 210 to move relative to each other, so that when there is flow air passing through the device, each W-shaped filter 111 can be automatically unfolded. At the same time, when there is airflow passing through the air duct housing 100 to rotate the fan blades 720, the fan blades 720 can drive the winding drum 900 to rotate when rotating, and the winding drum 900 can wrap and stretch the elastic rope 920 when rotating. Different airflow velocities in the air duct housing 100 will cause the fan blades 720 to overcome the elastic potential energy of the elastic rope 920 and do work, and the rotation angles are different. The greater the airflow velocity, the greater the rotation angle of the fan blades 720. The larger the opening angle of the V-shaped connecting end 200, the larger the expanded area of each W-shaped filter 111, thereby increasing the filtering efficiency of the foldable filter 110. When the airflow velocity decreases or there is no airflow, the wound and stretched elastic rope 920 will drive the winding reel 900 to rotate in the opposite direction, reducing the opening angle of the V-shaped connecting end 200 and retracting the foldable filter 110, allowing the device to automatically adjust the filtering efficiency of the foldable filter 110 according to the airflow velocity in the air duct housing 100.

[0044] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic negative pressure maintaining device for a biosafety cabinet, comprising a cabinet body (4) of the biosafety cabinet, characterized in that: An automatic negative pressure maintaining portion is provided at the upper end of the cabinet (4), and the automatic negative pressure maintaining portion has an air duct (1) in communication with the cabinet (4). The air duct (1) and the cabinet (4) are in communication via a ventilation opening, and an air duct one-way valve is provided at the ventilation opening. A fan and an air filter (10) are provided in the air duct (1); The air filter (10) comprises an air duct housing (100) installed on the left and right sides of the air duct (1), wherein foldable filter screens (110) are fixedly installed on the left and right sides of the inner wall of the air duct housing (100), wherein the foldable filter screens (110) are formed by connecting a plurality of W-shaped filter screens (111), and a V-shaped connecting end (200) is provided at the connection between two adjacent W-shaped filter screens (111), and a wedge-shaped block (210) is provided inside the V-shaped connecting end (200) on the left and right sides, and the wedge-shaped block (210) drives the V-shaped connecting end (200) on the left and right sides to move left and right; The lower ends of the outer walls of the two wedge-shaped blocks (210) are fixedly mounted with sliding blocks 1 (310), the lower ends of the left and right sides of the inner wall of the air duct housing (100) are fixedly mounted with connecting blocks (400), and the opposite sides of the inner walls of the left and right connecting blocks (400) are fixedly mounted with slide rail frames (300), and the two sliding blocks 1 (310) are slidably connected to the inner wall of the slide rail frame (300), and the inner walls of the left and right connecting blocks (400) are rotatably connected with screw rods (410) located at the rear end of the slide rail frame (300), and the thread directions of the left and right sides of the screw rods (410) are opposite, and the outer walls of the screw rods (410) are symmetrically threadedly connected with sliding blocks 2 (420), and the lower ends of the outer walls of the two sliding blocks 2 (420) are fixedly mounted with n-type connecting rods (430), and the front end of each n-type connecting rod (430) is fixedly connected to the lower end of the outer wall of the sliding block 1 (310) on the corresponding side; A bevel gear 1 (500) is fixedly installed in the middle of the outer wall of the screw rod (410), and a connecting frame 1 (600) is fixedly installed on the inner walls of the left and right connecting blocks (400) and located at the rear end of the screw rod (410). The upper end of the outer wall of the connecting frame 1 (600) is fixedly installed by a support rod (700), and the upper end of the outer wall of the support rod (700) is rotatably connected to a rotating shaft 1 (710). The front section of the outer wall of the rotating shaft 1 (710) passes through the rear side of the outer wall of the support rod (700) and is fixedly installed with a fan blade (720). The rear end of the outer wall of the fan blade (720) is fixedly installed with a bevel gear 2 (730). The outer wall of the connecting frame 1 (600) is fixedly installed with a support rod (700). Connecting frame 2 (800) is symmetrically fixedly installed on the left and right sides of the end, and fixing blocks (810) are fixedly installed on the upper ends of the outer walls of the two connecting frames 2 (800) at the same time. The fixing blocks (810) are internally connected to the rotating shaft 2 (820), and the upper and lower ends of the outer wall of the rotating shaft 2 (820) are fixedly installed with bevel gear 3 (830). The connecting frame 1 (600) is internally connected to the rotating shaft 3 (601), and the front and rear ends of the outer wall of the rotating shaft 3 (601) are fixedly installed with bevel gear 4 (610), and the bevel gear 4 (610) on the front and rear sides are respectively engaged with the bevel gear 1 (500) and the bevel gear 3 (830).

2. The automatic negative pressure maintaining device for a biological safety cabinet according to claim 1, characterized in that: An ultraviolet sterilization lamp is also provided in the air duct (1), and the ultraviolet sterilization lamp is provided upstream in the ventilation direction of the air duct (1).

3. The automatic negative pressure maintaining device for a biological safety cabinet according to claim 1, characterized in that: The air filter (10) is a high-efficiency air filter (HEPA) and is arranged downstream in the ventilation direction of the air duct (1).

4. The automatic negative pressure maintaining device for a biological safety cabinet according to claim 1, characterized in that: A protective plate (510) is symmetrically fixedly installed on the outer wall of the screw (410) and located on the left and right sides of the bevel gear (500); a winding drum (900) is fixedly installed on the front section of the outer wall of the rotating shaft (710), an elastic rope (920) is wound around the inner wall of the winding drum (900), and a fixing rod (910) is fixedly installed at one end of the elastic rope (920) away from the winding drum (900), and the front end of the outer wall of the fixing rod (910) is fixedly connected to the rear end of the outer wall of the air duct housing (100).

5. The automatic negative pressure maintaining device for a biological safety cabinet according to claim 1, characterized in that: Connecting plates (120) are fixedly mounted on the left and right sides of the outer wall of the foldable filter (110), and the connecting plates (120) are fixedly connected to the inner wall of the air duct housing (100).

6. The automatic negative pressure maintaining device for a biological safety cabinet according to claim 1, characterized in that: The front of the cabinet (4) is provided with a transparent sealing plate, which includes an upper sealing plate (2) and a lower sealing plate (3). The upper sealing plate (2) is fixed, and the lower sealing plate (3) is openable and closable. The lower sealing plate (3) is opened and closed by sliding up and down along the guide rails on both sides. A rubber sealing strip (5) is provided at the opening and closing position between the lower edge of the lower sealing plate (3) and the cabinet (4). The rubber sealing strip (5) has a U-shaped groove, and the lower edge of the lower sealing plate (3) can be inserted into the U-shaped groove to achieve sealing.

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