A laboratory segmented variable air volume ventilation system

Abstract

This invention discloses a segmented variable air volume (VAV) ventilation system for laboratories, comprising several fume hoods arranged in a side-by-side array, and exhaust and make-up air ducts horizontally mounted above and behind the fume hoods, respectively. This invention relates to the field of ventilation system technology. This segmented VAV ventilation system equips each fume hood with a constant pressure output mechanism between its exhaust port and the exhaust duct, ensuring each fume hood has a buffer transition structure for exhaust gas output. During the exhaust duct design process, it eliminates the need to locate the geometric center of multiple fume hoods, reducing the complexity of installation design and improving adaptability to the installation environment. Furthermore, the constant pressure opening of the safety valve ensures a consistent exhaust gas pressure entering the exhaust duct from each fume hood. Simultaneously, a check valve is designed to prevent backflow of exhaust gas, effectively eliminating cross-flow between fume hoods.

Description

Technical Field

[0001] This invention relates to the field of ventilation system technology, specifically a laboratory segmented control variable air volume ventilation system. Background Technology

[0002] A search revealed Chinese patent CN102486331B, which discloses a segmented variable air volume (VAV) ventilation system for a laboratory, used to exhaust waste gas generated during scientific experiments to the outdoors. The system includes: a variable frequency fan, a plenum chamber, dampers, and fume hoods. The first ventilation segment is from the variable frequency fan to the plenum chamber, where the fan is installed on the roof or outdoors and connected to the plenum chamber via ventilation ducts. The plenum chamber is installed near the ventilation terminals, specifically at the geometric center of the multiple fume hoods within the system. A pressure sensor is installed at the plenum chamber to detect the air pressure and adjust the fan speed accordingly. The second ventilation segment is from the plenum chamber to the terminals, where the plenum chamber is connected to the fume hoods via ventilation ducts. A manual damper is installed between the plenum chamber and the fume hoods for equalizing airflow, and an electric damper is installed for variable airflow control during operation. This invention employs a segmented control mode for ventilation, achieving accurate adjustment of airflow at each stage and reducing ventilation noise and energy consumption.

[0003] This patent addresses the issue of static pressure boxes, which are set at the geometric center of multiple fume hoods and serve as transition buffer boxes for the ventilation ducts of each fume hood. This ensures that the length of each first ventilation section is the same, guaranteeing sufficient exhaust air volume for each fume hood. However, in actual use, due to differences in the installation environment of each laboratory, it is impossible to guarantee that the static pressure box is set at the geometric center of multiple fume hoods. The installation process is cumbersome, and the installation environment is quite limited. In addition, when a fume hood is opened later, cross-flow can easily occur because the first ventilation end connected to it is filled with exhaust gas. Therefore, the applicant has designed a laboratory segmented control variable air volume ventilation system to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a laboratory segmented control variable air volume ventilation system, which solves the problems of cumbersome installation process, limited installation environment, and easy cross-flow of air when the fume hood is turned on later.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a laboratory segmented variable air volume ventilation system, comprising a plurality of fume hoods arranged in a side-by-side array, and exhaust and makeup air ducts respectively horizontally mounted above the rear and front sides of the fume hoods.

[0006] The fume hood includes a cabinet body, and exhaust ports and make-up air ports respectively located on the rear and front sides of the top of the cabinet body, both distributed vertically. The exhaust ports are connected to the exhaust duct via a constant pressure output mechanism.

[0007] The constant pressure output mechanism includes a buffer chamber, a safety valve, and a check valve. The buffer chamber is distributed vertically, and the safety valve and check valve are respectively flanged and assembled at the output and input ends of the buffer chamber.

[0008] Preferably, the exhaust duct includes an indoor exhaust duct section, an outdoor exhaust duct section, and a roof exhaust duct section that are sequentially flanged together along the exhaust gas output direction, as well as a variable frequency fan cabinet located at the output end of the roof exhaust duct section and fixedly mounted on the roof. An adsorption box is installed between the variable frequency fan cabinet and the output end of the roof exhaust duct section, and the output ends of several safety valves are all connected to the indoor exhaust duct section through centrifugal fans.

[0009] Preferably, it also includes a pressure gauge that runs through and is electrically connected to the variable frequency fan cabinet on the outdoor exhaust duct section. The outdoor exhaust duct section is erected vertically and has a mounting hole on its outer side. The pressure gauge includes a Pitot tube with an L-shaped structure. A flange that matches the mounting hole is welded to the outside of the Pitot tube. A heat-resistant filling material is provided between the Pitot tube and the mounting hole.

[0010] Preferably, all of the aforementioned air supply ports are connected to the air supply pipeline via an electric butterfly valve mounted on the top of the flange.

[0011] Preferably, the make-up air duct includes an indoor make-up air duct section and an outdoor make-up air duct section, as well as an air purifier located indoors for connecting the two.

[0012] Preferably, the purifier includes a box body and a box cover distributed vertically, and filter plates, a fan, and plasma tubes arranged sequentially from left to right on the box body. Assuming there is a partition in the middle of the box body, there are two filter plates arranged in a V-shape on the left side of the partition, the fan is mounted on the partition and the left and right sides of the partition are connected, and there are several plasma tubes arranged horizontally on the right side of the partition through a mesh frame. A ballast is provided on the right side of the partition for electrical connection of the several plasma tubes.

[0013] Preferably, the bottom of each of the two filter screens is provided with a number of equally spaced parallel slots, and the inner side of the box cover is provided with a protrusion that matches the inner wall of the box. The protrusion is provided with two mounting slots for the two filter screens to be fitted and accommodated, and each of the two mounting slots is provided with a number of positioning strips that match the slots.

[0014] Beneficial effects

[0015] This invention provides a laboratory segmented variable air volume ventilation system. Compared with the prior art, it has the following advantages:

[0016] This laboratory's segmented variable air volume (VAV) ventilation system features a constant pressure output mechanism installed between the exhaust port and the exhaust duct of each fume hood. This ensures that each fume hood has a buffer transition structure for exhaust gas output. During the exhaust duct design process, it is not necessary to find the geometric center of multiple fume hood locations, reducing the complexity of installation design and improving the adaptability to the installation environment. In addition, the constant pressure opening of the safety valve ensures that the exhaust gas pressure discharged into the exhaust duct of each fume hood is constant. Furthermore, the design includes a check valve to prevent exhaust gas backflow and effectively eliminate cross-flow between fume hoods. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of the fume hood of the present invention;

[0019] Figure 3 This is a schematic diagram of the constant pressure output mechanism of the present invention;

[0020] Figure 4 This is a schematic diagram of the exhaust duct structure of the present invention;

[0021] Figure 5 This is a schematic diagram of the pressure measuring instrument of the present invention;

[0022] Figure 6 This is a schematic diagram of the air supply duct of the present invention;

[0023] Figure 7 This is a schematic diagram of the air purifier of the present invention;

[0024] Figure 8 This is a schematic diagram of the structure of the box lid of the present invention;

[0025] In the picture:

[0026] 100. Fume hood;

[0027] 110. Cabinet; 120. Exhaust port; 130. Make-up air port;

[0028] 200. Exhaust ductwork;

[0029] 210. Indoor exhaust duct section; 220. Outdoor exhaust duct section; 230. Roof exhaust duct section; 240. Variable frequency fan cabinet; 250. Adsorption box; 260. Pressure gauge;

[0030] 2210. Mounting hole base;

[0031] 2610, Pitot tube; 2620, Flange; 2630, Heat-resistant filler material;

[0032] 300. Makeup air duct;

[0033] 310. Indoor make-up air duct section; 320. Outdoor make-up air duct section; 330. Air purifier;

[0034] 3310, Box body; 3320, Box cover; 3330, Filter screen; 3340, Fan; 3350, Plasma tube; 3360, Partition; 3370, Mesh frame; 3380, Ballast; 3390, Slot;

[0035] 3321. Protrusion; 3322. Mounting groove; 3323. Positioning strip;

[0036] 400. Constant pressure output mechanism;

[0037] 410. Buffer chamber; 420. Safety valve; 430. Check valve; 440. Centrifugal fan;

[0038] 500. Electric butterfly valve. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Please see Figure 1 , Figure 2 and Figure 3 The present invention provides a technical solution: a laboratory segmented control variable air volume ventilation system, comprising a plurality of fume hoods 100 arranged in a side-by-side array, and exhaust ducts 200 and make-up air ducts 300 respectively horizontally mounted above the rear and front sides of the plurality of fume hoods 100.

[0041] The fume hood 100 includes a cabinet 110, and an exhaust port 120 and a make-up air port 130 respectively located on the rear and front sides of the top of the cabinet 110 and distributed vertically. The exhaust port 120 is connected to the exhaust duct 200 through a constant pressure output mechanism 400. The constant pressure output mechanism 400 includes a buffer chamber 410, a safety valve 420 and a check valve 430. The buffer chamber 410 is distributed vertically, and the safety valve 420 and the check valve 430 are respectively flanged and assembled at the output end and input end of the buffer chamber 410.

[0042] Based on the above structural configuration, the laboratory's segmented variable air volume (VAV) ventilation system consists of an exhaust duct 200, a makeup air duct 300, several fume hoods 100, and several constant pressure output mechanisms 400. The fume hoods 100 are arranged in a side-by-side array. The exhaust duct 200 and makeup air duct 300 are horizontally mounted above the fume hoods 100 on their rear and front sides, respectively. Each constant pressure output mechanism 400 is paired with one fume hood 100. The constant pressure output mechanism 400 facilitates the connection between the exhaust port 120 of the fume hood 100 and the exhaust duct 200. Specifically, during operation, taking a single fume hood 100 as an example, the exhaust gas generated during the experiment inside the hood 110 is output from the exhaust port 120 and sent into the buffer chamber 410 by the internal fan. Since the initial amount of exhaust gas sent into the buffer chamber 410 is small, it cannot trigger the pressure value set by the safety valve 420. At the same time, under the action of the check valve 430, the exhaust gas cannot flow back and accumulates in the buffer chamber 410. Until the pressure inside the buffer chamber 410 exceeds the pressure value set by the safety valve 420, the exhaust gas inside the buffer chamber 410 is input into the exhaust duct 200. Since the exhaust gas pressure input into the exhaust duct 200 from each fume hood 100 is fixed, there will be no cross-flow of exhaust gas after it is input into the exhaust duct 200. Finally, as the exhaust duct 200 outputs, the laboratory's segmented variable air volume ventilation system, through the installation of a constant pressure output device between the exhaust port 120 of each fume hood 100 and the exhaust duct 200, completes the process. The structure 400 ensures that each fume hood 100 is equipped with a buffer transition structure for exhaust gas output. During the design of the exhaust duct 200, it is not necessary to find the geometric center of multiple fume hoods 100, reducing the complexity of installation design and improving the adaptability to the installation environment. In addition, the safety valve 420 opens at constant pressure, ensuring that the exhaust gas pressure discharged from each fume hood 100 into the exhaust duct 200 is constant. At the same time, a check valve 430 is designed to prevent exhaust gas backflow and effectively prevent cross-flow between fume hoods 100.

[0043] For further details, please refer to Figure 1 and Figure 4The exhaust duct 200 includes an indoor exhaust duct section 210, an outdoor exhaust duct section 220, and a roof exhaust duct section 230, which are sequentially flanged and connected along the exhaust gas output direction. A variable frequency fan cabinet 240 is located at the output end of the roof exhaust duct section 230 and fixedly mounted on the roof. An adsorption box 250 is installed between the variable frequency fan cabinet 240 and the output end of the roof exhaust duct section 230. The output ends of several safety valves 420 are all connected to the indoor exhaust duct section 210 through centrifugal fans 440. The exhaust duct 200 is used for the output of waste gas, while the makeup air duct 300 is used for the input of outdoor air to ensure stable indoor air pressure and achieve ventilation. Specifically, in the layout process, the exhaust duct 200 and the makeup air duct 300 extend to the outside in opposite directions to avoid backflow of the output gas. At the same time, the exhaust duct 200 extends sequentially through the horizontally arranged indoor exhaust duct section 210, the vertically arranged outdoor exhaust duct section 220, and the horizontally arranged roof exhaust duct section 230. The system extends to the roof and is equipped with an adsorption box 250 and a variable frequency fan cabinet 240 at the output end. The variable frequency fan cabinet 240 provides power for the exhaust gas to be output from the exhaust duct 200, while the adsorption box 250 is used to purify the exhaust gas. Furthermore, as a preferred option, by installing a centrifugal fan 440 at the output end of each constant pressure output mechanism 400, it is helpful for the exhaust gas to transition quickly from the buffer chamber 410 to the exhaust duct 200, while reducing the workload of the variable frequency fan cabinet 240.

[0044] For further details, please refer to Figure 4 and Figure 5It also includes a pressure gauge 260 that runs through and is electrically connected to the variable frequency fan cabinet 240 on the outdoor exhaust duct section 220. The outdoor exhaust duct section 220 is erected vertically and has a mounting hole seat 2210 on its outer side. The pressure gauge 260 includes a Pitot tube 2610 with an L-shaped structure. A flange 2620 that is adapted to the mounting hole seat 2210 is welded to the outside of the Pitot tube 2610. A heat-resistant filling material 2630 is provided between the Pitot tube 2610 and the mounting hole seat 2210. In this process, a pressure gauge 260 is installed in the outdoor exhaust duct section 220. With the help of a pitot tube 2610 electrically connected to the variable frequency fan cabinet 240, the output power of the variable frequency fan cabinet 240 can be adjusted in real time based on the measured exhaust gas pressure in the exhaust duct 200, thereby ensuring the ventilation effect. Specifically, in the actual installation process, the heat-resistant filling material 2630 used is asbestos rope. The operator first cleans and inspects the outer wall of the pitot tube 2610 penetration part, then cuts the asbestos rope to the required length and twists it into a rope shape by hand. Then, the twisted asbestos rope is wrapped tightly around the outer wall of the sealing position of the pitot tube 2610 without leaving any gaps. Then, the operator applies a layer of sealant or lubricating oil to the surface of the asbestos rope to increase the sealing performance of the asbestos rope and compresses the asbestos rope into the mounting hole 2210. Finally, the operator assembles the flange 2620 onto the mounting hole 2210 with bolts.

[0045] For further details, please refer to Figure 6 Several make-up air ports 130 are connected to the make-up air pipeline 300 via electric butterfly valves 500 mounted on their top flanges. The electric butterfly valves 500 not only allow the make-up air ports 130 to be opened and closed, but also allow the opening and closing angle of the butterfly valves to be adjusted in real time by means of the rotation angle of the motor of the electric butterfly valve 500.

[0046] For further details, please refer to Figure 1 and Figure 6 The make-up air duct 300 includes an indoor make-up air duct section 310 and an outdoor make-up air duct section 320, as well as a purifier 330 located indoors to connect the two. The make-up air duct 300 is used to supply air to ensure stable air pressure within the laboratory and to achieve air exchange. The make-up air duct 300 is typically configured as a straight duct. The purifier 330, located between the outdoor make-up air duct section 320 and the indoor make-up air duct section 310, is used to purify the outside air supplied to the laboratory.

[0047] For further details, please refer to Figure 6 and Figure 7The purifier 330 includes a box body 3310 and a box cover 3320 arranged vertically, and a filter plate 3330, a fan 3340 and a plasma tube 3350 arranged sequentially from left to right in the box body 3310. It is assumed that there is a partition 3360 in the middle of the box body 3310. There are two filter plates 3330, and the two filter plates 3330 are arranged in a V-shape on the left side of the partition 3360. The fan 3340 is mounted on the partition 3360 and the left and right sides of the partition 3360 are connected. There are several plasma tubes 3350, and they are all horizontally arranged on the right side of the partition 3360 through a mesh frame 3370. A ballast 3380 is provided on the right side of the partition 3360 for the several plasma tubes 3350 to be electrically connected. The system replaces the traditional single filter plate 3330 with two filter plates 3330, which extends the filtration time of the purifier 330 and eliminates the need for frequent filter plate replacements. At the same time, the two filter plates 3330, which are symmetrically distributed in a V-shape, increase the contact area between the incoming air and the filter plates 3330, further improving the filtration effect. In addition, several plasma tubes 3350 are used to disinfect the incoming air, enhancing the overall purification effect of the purifier 330.

[0048] For further details, please refer to Figure 7 and Figure 8 The bottom of each of the two filter plates 3330 is provided with several equally spaced parallel slots 3390. The inner side of the cover 3320 is provided with a protrusion 3321 that matches the inner wall of the box body 3310. The protrusion 3321 is provided with two mounting grooves 3322 for the two filter plates 3330 to be fitted and accommodated respectively. Each of the two mounting grooves 3322 is provided with several positioning strips 3323 that match the slots 3390. The layout with the box body 3310 on top and the cover 3320 on the bottom facilitates the operator to perform disassembly and maintenance work from the bottom. For the two filter plates 3330 that are symmetrically distributed in a V-shape, it is preferable to provide mounting grooves 3322 for each of them to be fitted and several positioning strips 3323 on the cover 3320, so as to realize quick positioning and fitting of the filter plates 3330 on the cover 3320, thereby improving the maintenance and replacement efficiency of the filter plates 3330.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laboratory segmented control variable air volume ventilation system, comprising a number of fume hoods (100) arranged in a side-by-side array, and exhaust ducts (200) and make-up air ducts (300) respectively horizontally mounted on the rear and front sides above the number of fume hoods (100); The fume hood (100) includes a cabinet (110), and an exhaust port (120) and a make-up air port (130) respectively located on the rear and front sides of the top of the cabinet (110) and distributed in the vertical direction. The exhaust port (120) is connected to the exhaust duct (200) through a constant pressure output mechanism (400). Its features are: The constant pressure output mechanism (400) includes a buffer chamber (410), a safety valve (420), and a check valve (430). The buffer chamber (410) is distributed in a vertical direction, and the safety valve (420) and the check valve (430) are respectively flanged and assembled at the output end and input end of the buffer chamber (410).

2. The laboratory segmented variable air volume ventilation system according to claim 1, characterized in that: The exhaust duct (200) includes an indoor exhaust duct section (210), an outdoor exhaust duct section (220), and a roof exhaust duct section (230) that are sequentially flanged together along the exhaust gas output direction, as well as a variable frequency fan cabinet (240) located at the output end of the roof exhaust duct section (230) and fixedly mounted on the roof. An adsorption box (250) is installed between the variable frequency fan cabinet (240) and the output end of the roof exhaust duct section (230). The output ends of several safety valves (420) are all connected to the indoor exhaust duct section (210) through a centrifugal fan (440).

3. A laboratory segmented variable air volume ventilation system according to claim 2, characterized in that: It also includes a pressure gauge (260) that runs through and is electrically connected to the variable frequency fan cabinet (240) on the outdoor exhaust duct section (220). The outdoor exhaust duct section (220) is erected vertically and has a mounting hole seat (2210) on its outer side. The pressure gauge (260) includes a Pitot tube (2610) with an L-shaped structure. A flange (2620) that is adapted to the mounting hole seat (2210) is welded to the outside of the Pitot tube (2610). A heat-resistant filling material (2630) is provided between the Pitot tube (2610) and the mounting hole seat (2210).

4. A laboratory segmented variable air volume ventilation system according to claim 1, characterized in that: Several of the aforementioned air supply ports (130) are connected to the air supply pipeline (300) via electric butterfly valves (500) mounted on their top flanges.

5. A laboratory segmented variable air volume ventilation system according to claim 1, characterized in that: The make-up air duct (300) includes an indoor make-up air duct section (310) and an outdoor make-up air duct section (320), as well as an air purifier (330) installed indoors to connect the two.

6. A laboratory segmented variable air volume ventilation system according to claim 5, characterized in that: The purifier (330) includes a box body (3310) and a box cover (3320) distributed vertically, and a filter plate (3330), a fan (3340), and a plasma tube (3350) arranged sequentially from left to right in the box body (3310). A partition (3360) is assumed to be located in the middle of the box body (3310). Two filter plates (3330) are provided, and the two filter plates (3330) are arranged in a V-shape. The structure is mounted on the left side of the partition (3360). The fan (3340) is mounted on the partition (3360) and the left and right sides of the partition (3360) are connected. Several plasma tubes (3350) are provided and are all horizontally mounted on the right side of the partition (3360) through the mesh frame (3370). The right side of the partition (3360) is provided with a ballast (3380) for electrical connection of several plasma tubes (3350).

7. A laboratory segmented variable air volume ventilation system according to claim 6, characterized in that: The bottom of each of the two filter plates (3330) is provided with several equally spaced parallel slots (3390). The inner side of the cover (3320) is provided with a protrusion (3321) that matches the inner wall of the box body (3310). The protrusion (3321) is provided with two mounting grooves (3322) for the two filter plates (3330) to be fitted and accommodated respectively. Each of the two mounting grooves (3322) is provided with several positioning strips (3323) that match the slots (3390).

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