Low-resistance-loss automatic closing three-way connecting pipe of local fan

Abstract

The utility model relates to the technical field of tunneling ventilation equipment for coal mines, non-coal mine mines, highways, railways and subways, and discloses a low-resistance-loss automatic closing three-way connecting pipe of a local ventilator. The low-resistance-loss automatic-closing three-way connecting pipe of the local fan comprises a three-way body which comprises an air duct opening, and the air duct opening is communicated with the three-way body; the first air port is communicated with the three-way body; the second air port is communicated with the three-way body; the valve plate is movably arranged in the three-way body, and the valve plate is used for switching the first air opening and the second air opening; the valve plate is connected with the three-way body through the locking piece, and the locking piece is used for locking the position of the valve plate. According to the low-resistance-loss automatic closing three-way connecting pipe of the local ventilator, the problems that most of existing three-way connecting pipes are of a straight barrel welding type structure, the resistance loss of the ventilator is too large due to large wind resistance, fan surge is likely to happen, and the opening angle of a wind shield in the three-way connecting pipe is inconvenient to adjust are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mine ventilation equipment, in particular to a low-resistance-loss automatic closing three-way pipe for a local ventilator. Background Art

[0002] Mining local fans, including those in tunnel mining ventilation systems, feature three-way pipes, a key component connecting the main and backup local fan vents. Their performance directly impacts mine ventilation efficiency and safety. The straight-tube welded three-way pipe structure currently widely used in the market, while simple to manufacture, has significant drawbacks. First, the straight-tube design results in high wind resistance, which easily forms eddies and turbulence during airflow. This increases fan load and leads to additional resistance losses. Long-term operation can easily cause fan surge, which not only reduces ventilation efficiency but can also damage the fan, impacting the safe operation of mine and tunnel operations.

[0003] Furthermore, the internal windshield of this type of three-way pipe is simplistically designed and lacks the necessary indexing and limiting devices, making it difficult to precisely adjust the windshield's opening angle. When rapid switching between primary and backup local fans is required, the windshield cannot be quickly and accurately adjusted to the desired position, resulting in an awkward airflow transition and potential localized airflow disturbances or leaks, compromising ventilation effectiveness. Furthermore, the inability to adjust the windshield to meet the mine's actual ventilation needs (such as operating two fans simultaneously when necessary) limits the optimization potential of the ventilation system. Utility Model Content

[0004] The purpose of the utility model is to provide a low-resistance-loss automatically closing three-way pipe for a local fan, which solves the problem that most existing three-way pipes are straight-tube welded structures, have high wind resistance and are prone to fan surge, and the opening angle of the wind shield inside the three-way pipe is inconvenient to adjust.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] An embodiment of the present utility model provides a low-resistance-loss automatically closed three-way pipe for a local ventilation fan, comprising: a three-way body, the three-way body comprising an air cylinder port, the air cylinder port being connected to the three-way body; a first air port, the first air port being connected to the three-way body; a second air port, the second air port being connected to the three-way body; a valve plate, the valve plate being movably arranged inside the three-way body, the valve plate being used to switch between the first air port and the second air port, or to connect the first air duct, the second air duct and the three-way body at the same time; a locking member, the valve plate being connected to the three-way body via the locking member, and the locking member being used to lock the position of the valve plate.

[0007] According to any of the aforementioned embodiments of the present invention, the first air outlet, the second air outlet, and the tee body form a "Y"-shaped structure, and the connection between the first air outlet, the second air outlet and the tee body is a smooth transition.

[0008] According to any of the aforementioned embodiments of the present invention, the air outlet areas of the first air outlet and the second air outlet are the same.

[0009] According to any of the aforementioned embodiments of the present invention, the area of ​​the air duct opening is the same as the area of ​​the air outlet.

[0010] According to any of the aforementioned embodiments of the present utility model, the area of ​​the air duct opening is twice the area of ​​the air outlet.

[0011] According to any of the aforementioned embodiments of the present invention, the valve plate has a first position, a second position and a third position. In the first position, the valve plate seals the first air duct; in the second position, the valve plate seals the second air duct; in the third position, the first air duct, the second air duct and the three-way body are connected at the same time.

[0012] According to any of the aforementioned embodiments of the present invention, the locking member includes a connecting rod and a handle, the connecting rod includes a cross rod and a vertical plate arranged perpendicular to each other; the valve plate and the cross rod are fixedly connected; the valve plate is connected to the intersection of the three-way body and the first air duct and the second air duct through the cross rod, and the handle is arranged at one end of the vertical plate, and the handle can drive the cross rod to rotate through the vertical plate to drive the valve plate to switch positions.

[0013] According to any of the aforementioned embodiments of the present invention, the locking member further includes a positioning plate and a positioning pin; the positioning pin is connected to the handle; the positioning plate is arranged at the intersection of the tee body and the outer surfaces of the first air duct and the second air duct; the cross bar is rotatably connected to the positioning plate; the vertical plate is located on the outside of the positioning plate; the positioning plate is also evenly provided with a plurality of positioning holes, and one end of the positioning pin can extend into the positioning hole and engage with the positioning hole to lock the position of the valve plate.

[0014] According to any of the aforementioned embodiments of the present invention, at least three positioning holes are provided on the positioning plate, and when the positioning pin is inserted into three different positioning holes, the valve plate can be located at the first position, the second position or the third position.

[0015] According to any of the aforementioned embodiments of the present invention, a sealing ring is further included, which is arranged in the three-way body and is used to seal the connection between the valve plate and the three-way body.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention optimizes the ventilation system by effectively switching airflow paths through a low-resistance tee. Based on the actual usage requirements of the two fans, the valve plate moves within the tee body, automatically adjusting the airflow direction and reducing ventilation resistance, thereby improving the system's overall ventilation efficiency, ensuring optimal fan performance under different operating conditions, and avoiding energy waste due to increased resistance. The system can adjust the opening and closing state of the valve plate as needed. Combined with the use of a locking member, the valve plate can be accurately positioned and secured, effectively preventing it from swinging and reducing airflow disturbances. In traditional ventilation systems, airflow passing through multiple turns and turns can cause significant resistance losses; this tee reduces this loss through a smooth and fluid-dynamically compliant flow path structure. The valve plate can be effectively secured through manual or automatic closing, avoiding unnecessary airflow disturbances and improving the system's overall efficiency. Compared to traditional structures, the present invention features a tee with a fixed valve plate structure. The valve plate is more securely fixed, reducing air leakage, extending the service life of the valve plate, and reducing air disturbances. The typical feature of the three-way pipe of the utility model is low resistance loss. The three-way pipe has a smooth transition, which effectively reduces the resistance loss at the fan outlet and extends the service life of the three-way pipe. At the same time, due to the smooth movement of the airflow, the service life of the local fan is also extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of an embodiment of a local ventilation fan with low resistance loss and automatic closing of a three-way pipe according to the present invention.

[0020] Figure 2 This is a schematic diagram from another angle of an embodiment of a local ventilator with low resistance loss and automatic closing of a three-way pipe according to the present utility model;

[0021] Figure 3 A schematic diagram of a valve plate and a locking member of an embodiment of a low-resistance-loss automatic closing three-way pipe for a local ventilator according to the present utility model;

[0022] Figure 4 This is a schematic diagram of the installation of two different specifications of three-way pipes of an embodiment of a local ventilation fan with low resistance loss and automatic closing of the three-way pipe according to the present utility model.

[0023] Description of reference numerals:

[0024] 100- tee body; 110- air duct outlet;

[0025] 200-first air duct;

[0026] 300-second air duct;

[0027] 400-valve plate;

[0028] 500-locking member; 510-connecting rod; 5101-crossbar; 5102-vertical plate; 520-handle; 530-positioning plate; 540-positioning pin; 550-return spring;

[0029] 600-Local ventilation fan.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0034] See also Figures 1 to 4As shown, an embodiment of the utility model provides a low-resistance-loss automatically closed three-way pipe for a local ventilation fan, comprising: a three-way body 100, the three-way body 100 including an air cylinder port 110, the air cylinder port 110 being connected to the three-way body 100; a first air duct 200, the first air duct 200 being connected to the three-way body 100; a second air duct 300, the second air duct 300 being connected to the three-way body 100; a valve plate 400, the valve plate 400 being movably arranged inside the three-way body 100, the valve plate 400 being used to seal the first air duct 200 or the second air duct 300, or to connect the first air duct 200, the second air duct 300 and the three-way body 100 at the same time; a locking member 500, the valve plate 400 being connected to the three-way body 100 via the locking member 500, and the locking member 500 being used to lock the position of the valve plate 400. The tee body 100 includes three main openings: a duct opening 110 for connecting to a duct or other air duct. Airflow in the first duct 200 and / or second duct 300 can enter the duct or other air duct through the duct opening 110 of the tee body 100. The first duct 200 connects to the air outlet of the first fan and discharges air into the tee body 100. The second duct 300 connects to the air outlet of the second fan and discharges air into the tee body 100. The valve plate 400 moves within the tee body 100. When the first fan is operating alone, the valve plate 400, under the influence of wind pressure, moves to seal the air outlet of the second fan, enabling rapid switching between the two fans. When the second fan is operating alone, the valve plate 400, under the influence of wind pressure, moves to seal the air outlet of the first fan, enabling rapid switching between the two fans. When the first and second fans are operating simultaneously, the valve plate 400 is positioned horizontally in the middle, increasing airflow to meet specific usage scenarios.

[0035] The locking member 500 is used to secure the position of the valve plate 400, ensuring that the valve plate 400 remains stable when required. The locking member 500 prevents accidental movement of the valve plate 400 during operation, thereby ensuring stable airflow and reducing disturbances or air leakage. The valve plate 400 has a first position, a second position, and a third position. In the first position, the valve plate 400 seals the first air duct 200, and the second fan operates. In the second position, the valve plate 400 seals the second air duct 300, and the first fan operates. In the third position, the first and second air ducts 200, 300, and the three-way body 100 are simultaneously connected, and the first and second fans operate simultaneously to cope with special scenarios such as mine disasters and the urgent need to increase ventilation volume. The locking member 500 ensures the stability and reliability of the valve plate 400 in the set position, preventing the position of the valve plate 400 from changing due to external factors such as vibration and airflow impact. The valve plate 400 will not accidentally move due to external forces or improper operation, thereby improving the stability and operational safety of the system. By reducing unnecessary resistance losses during fluid flow through the tee, ventilation efficiency can be effectively improved, power consumption can be reduced, and significant energy savings can be achieved over the long term. The design of the locking element 500 ensures that the valve plate 400 remains in place during use, extending its service life and thus improving system safety.

[0036] In some embodiments, the first air duct 200, the second air duct 300, and the tee body 100 form a "Y"-shaped structure, and the connection between the first air duct 200 and the second air duct 300 and the tee body 100 is a smooth transition. The smooth transition design can effectively reduce the turbulence and pressure loss of the air flow during the air outlet conversion process, reduce the proportion of useless work, and significantly save electricity. Compared with traditional sharp-angle connections, the smooth transition provides a smoother airflow path, reduces the interference and resistance of the air flow. The smooth transition can effectively reduce the airflow resistance, improve the ventilation efficiency of the system, and reduce the energy consumption of the fan. The smooth transition can reduce the speed change of the air flow at the corner, making the air flow more stable. Stable airflow not only improves the performance of the ventilation system, but also reduces noise and vibration. Sharp angles and sharp airflow turns may cause increased wear in the air duct, and the smooth transition reduces this wear through smooth transition. In long-term use, the smooth flow reduces stress and damage inside the air duct, which helps to extend the service life of the equipment and reduce maintenance and replacement costs.

[0037] Figure 4This is a schematic diagram of the installation of two different specifications of three-way pipes and a local ventilation fan 600 in an embodiment of an embodiment of the utility model for automatically closing a three-way pipe with low resistance loss for a local ventilation fan. In some embodiments, the areas of the first air duct 200 and the second air duct 300 are the same. When the first air duct 200 and the second air duct 300 are the same, they can be set up redundantly, one for backup and the other for use. In special circumstances (such as a disaster state, when the ventilation volume needs to be increased), two first fans and second fans of the same model can also operate at the same time. In practical applications, standardized air outlet sizes can reduce manufacturing complexity, reduce production costs, and simplify quality control. Regardless of which of the two local fans is working, the airflow through the air outlets of the same area can maintain a relatively consistent resistance, which reduces the additional resistance loss caused by uneven area during the conversion of the airflow, thereby improving the overall energy efficiency of the system.

[0038] In some embodiments, the area of ​​the air duct opening 110 is identical to that of the first air duct 200 / second air duct 300. Having the air duct opening 110 and the air outlet have the same area ensures a smooth transition of airflow within the duct system, maintains airflow stability, and reduces pressure loss or noise issues caused by uneven airflow. Having the air duct opening 110 and the first air duct 200 / second air duct 300 have the same area effectively reduces resistance losses caused by mismatched flow areas. The lack of a flow area difference between the air duct opening 110 and the fan outlet helps reduce pressure loss and eddy currents generated when air flows through the duct, thereby improving system energy efficiency. When the air duct opening 110 and the first air duct 200 / second air duct 300 have the same area, the various components of the system are more compatible and coordinated. This consistency ensures smooth airflow when different components are combined or replaced, avoiding compatibility issues caused by area mismatches. When air flows between the first air duct 200 / second air duct 30 and the air duct opening 110, which have the same area, noise caused by changes in air velocity and pressure loss is reduced.

[0039] In some embodiments, the area of ​​the air duct opening 110 is twice the area of ​​the first air duct 200 / the second air duct 30. When the area of ​​the air duct opening 110 is twice the area of ​​the first air duct 200 / the second air duct 300, the air flow speed at the air duct opening 110 is reduced. Since the area of ​​the air duct opening 110 is larger, the flow rate of the air flow is reduced when entering the air duct opening 110, which can significantly reduce the ventilation pressure loss, make the air flow in the air duct more stable, and improve the energy efficiency of the system. Reducing the air flow speed helps to reduce the noise in the air duct system. When the air flow speed is lower, the turbulence and vibration of the air flow are reduced, making the system run quieter; it helps to ensure that the air flow is more evenly distributed at the air outlet, thereby improving the ventilation effect. Reducing the air flow speed helps to reduce the wear and impact force inside the air duct and the three-way pipe external to the air duct. In special circumstances (such as disaster situations where increased ventilation volume is required), two first and second fans of the same model can operate simultaneously and enter the three-way pipe through the first air duct 200 and the second air duct 300 at the same time; since the area of ​​the air duct opening 110 is twice the area of ​​the first air duct 200 / the second air duct 300, an air pressure equal to the outlet air pressure of the first air duct 200 / the second air duct 300 can be established in the three-way pipe and the air outlet duct connected to the air duct opening 110, and the three-way pipe can also maintain a stable working state.

[0040] In some embodiments, the outlet area of ​​a push-in local fan is twice the area of ​​the inlet. This is primarily designed to ensure stable simultaneous operation of two fans in special situations, such as catastrophic conditions. If only one fan is operating, the larger outlet area than the inlet can divert and diffuse the airflow, reducing fan outlet resistance and noise.

[0041] In this embodiment, two different specifications of three-way pipes are provided, one suitable for single fan operation, and the other for two fans running in parallel, with twice the air volume. In the event of an accident underground or in a lane / tunnel, both local fans can be started at the same time.

[0042] In some embodiments, the valve plate 400 has a first position, a second position, and a third position. In the first position, the valve plate 400 is located on the side of the first air duct 200 and seals the first air duct 200; in the second position, the valve plate 400 is located on the side of the second air duct 300 and seals the second air duct 300; in the third position, the first air duct 200, the second air duct 300, and the tee body 100 are connected at the same time.

[0043] In some embodiments, the valve plate 400 has a first position and a second position. In the first position, the valve plate 400 is located beside the first air duct 200; in the second position, the valve plate 400 is located beside the second air duct 300. When the valve plate 400 is located beside the first air duct 200, it seals and blocks the first air duct 200. When the valve plate 400 is located beside the second air duct 300, it seals and blocks the second air duct 300.

[0044] In some embodiments, the locking member 500 includes a connecting rod 510 and a handle 520. The connecting rod 510 includes a horizontal bar 5101 and a vertical plate 5102 arranged perpendicular to each other. The valve plate 400 is fixedly connected to the horizontal bar 5101. The valve plate 400 is connected to the intersection of the tee body 100, the first air duct 200, and the second air duct 300 via the horizontal bar 5101. The handle 520 is located at one end of the vertical plate 5102. The handle 520 can rotate the horizontal bar 5101 via the vertical plate 5102, thereby driving the valve plate 400 to switch positions. The connecting rod 510 secures the valve plate 400 at the intersection of the tee body 100, the first air duct 200, and the second air duct 300, ensuring the stability of the valve plate 400 and allowing it to move between two positions. The handle 520 is located at one end of the connecting rod 510. The user controls the movement of the connecting rod 510 by operating the handle 520, thereby effectively securing the valve plate 400 after switching between the first and second positions.

[0045] In some embodiments, the locking member 500 further includes a positioning plate 530 and a positioning pin 540. The positioning pin 540 is connected to the handle 520. The positioning plate 530 is positioned at the intersection of the tee body 100 and the outer surfaces of the first and second air ducts 200 and 300. The positioning plate 530 is also uniformly provided with multiple positioning holes. When the positioning pins 540 are inserted into the positioning holes, the valve plate 400 is locked in place. The multiple positioning holes uniformly distributed on the positioning plate 530 enable the valve plate 400 to be precisely positioned in multiple preset positions. The positioning pins 540, inserted into these holes, ensure that the valve plate 400 is accurately fixed in the desired position during operation, enabling more precise airflow control and adjustment. The insertion of the positioning pins 540 not only locks the position of the valve plate 400 but also reduces potential vibration and displacement of the valve plate during operation. The user can adjust the position of the valve plate 400 by simply inserting or removing the positioning pins 540, without the need for complex tools or adjustments. Stable positioning reduces the relative movement between the valve plate 400 and the three-way body 100, thereby reducing wear caused by frequent adjustments. This not only extends the service life of the valve plate 400 and the connecting assembly, but also reduces the frequency of replacement and operation and maintenance costs. The accurate locking mechanism avoids airflow leakage or unevenness caused by the unstable position of the valve plate 400. The push-locking structure in this embodiment refers to the existing push-push structure of the push-type ballpoint pen, which is pressed to lock and then pressed to unlock; other locking results can also be used, as long as the position locking and unlocking of the valve plate 400 can be achieved; the locking member 500 also includes a reset spring 550, which is sleeved on the positioning pin 540, and the reset spring 550 is used to pop the handle 520 out of the positioning hole when pressed to unlock.

[0046] In a specific embodiment, the press-locking structure can adopt the existing self-locking indexing spring locating pin; the self-locking indexing spring locating pin, as the name implies, is composed of two parts: a self-locking indexing spring and a locating pin. Among them, the self-locking indexing spring plays the role of fixing the position of the locating pin, while the locating pin plays the role of precise positioning. Working principle: When the self-locking indexing spring locating pin is inserted into the fixing hole, the self-locking indexing spring will be compressed to form a pre-tightening force, causing it to produce initial elastic deformation to ensure that the position of the locating pin is fixed. When subjected to external forces, such as rotation, movement, etc., the self-locking indexing spring will produce elastic deformation, thereby moving the locating pin to a new position and generating a pre-tightening force at the new position to maintain positioning accuracy.

[0047] In a specific embodiment, at least three positioning holes are provided on the positioning plate 530. When the positioning pin 540 is inserted into three different positioning holes, the valve plate 400 can be located in the first position, the second position or the third position; the positioning pin fixes the position of the valve plate 400, thereby preventing the valve plate 400 from shaking under conditions such as changes in gas pressure, reducing disturbances, and ensuring ventilation stability.

[0048] In some embodiments, a sealing retaining ring is further included, which is arranged in the tee body 100 and is used to seal the connection between the valve plate 400 and the tee body 100. The sealing retaining ring is located at the connection between the valve plate 400 and the tee body 100, and the sealing retaining ring can ensure the effective limitation of the valve plate, thereby improving the efficiency and reliability of the system. By providing the sealing retaining ring, external impurities or contaminants can be prevented from entering the interior of the system. This not only protects the structure of the valve plate 400 and the tee body 100, reduces the impact of pollution on system performance, but also reduces the complexity of system maintenance. The sealing retaining ring can reduce the friction and wear between the valve plate 400 and the tee body 100. The sealing retaining ring provides a smooth sealing interface, which helps to reduce the mechanical wear of the valve plate 400 during operation, thereby extending the service life of system components.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A local fan with low resistance loss and automatic closing three-way pipe, characterized in that: include: A three-way body (100), the three-way body (100) comprising a wind tube opening (110), the wind tube opening (110) being in communication with the three-way body (100); a first air duct (200), the first air duct (200) being connected to the three-way body (100); a second air duct (300), the second air duct (300) being connected to the three-way body (100); a valve plate (400), the valve plate (400) being movably disposed inside the three-way body (100), the valve plate (400) being used to seal the first air duct (200) or the second air duct (300), or to simultaneously connect the first air duct (200), the second air duct (300) and the three-way body (100); A locking member (500), the valve plate (400) is connected to the three-way body (100) through the locking member (500), and the locking member (500) is used to lock the position of the valve plate (400).

2. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 1 is characterized in that: The first air duct (200), the second air duct (300), and the three-way body (100) form a "Y"-shaped structure, and the connection between the first air duct (200), the second air duct (300) and the three-way body (100) is a smooth transition.

3. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 1 is characterized in that: The air outlet areas of the first air duct (200) and the second air duct (300) are the same.

4. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 3 is characterized in that: The area of ​​the air duct opening (110) is the same as the area of ​​the air outlet.

5. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 3 is characterized in that: The area of ​​the air duct opening (110) is twice the area of ​​the air outlet.

6. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 1, characterized in that: The valve plate (400) has a first position, a second position, and a third position. In the first position, the valve plate (400) seals the first air duct (200); in the second position, the valve plate (400) seals the second air duct (300); and in the third position, the first air duct (200), the second air duct (300), and the three-way body (100) are connected at the same time.

7. The low resistance loss automatic closing three-way pipe for local ventilation according to claim 6, characterized in that: The locking member (500) includes a connecting rod (510) and a handle (520), wherein the connecting rod (510) includes a cross bar (5101) and a vertical plate (5102) arranged perpendicular to each other; the valve plate (400) and the cross bar (5101) are fixedly connected; the valve plate (400) is connected to the intersection of the three-way body (100) and the first air duct (200) and the second air duct (300) through the cross bar (5101), and the handle (520) is arranged at one end of the vertical plate (5102). The handle (520) can drive the cross bar (5101) to rotate through the vertical plate (5102), thereby driving the valve plate (400) to switch positions.

8. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 7, characterized in that: The locking member (500) further includes a positioning plate (530) and a positioning pin (540); the positioning pin (540) is connected to the handle (520); the positioning plate (530) is arranged at the intersection of the outer surfaces of the three-way body (100) and the first air duct (200) and the second air duct (300); the cross bar (5101) is rotatably connected to the positioning plate (530); the vertical plate (5102) is located outside the positioning plate (530); the positioning plate (530) is also evenly provided with a plurality of positioning holes, and one end of the positioning pin (540) can extend into the positioning hole and engage with the positioning hole to lock the position of the valve plate (400).

9. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 8, characterized in that: At least three positioning holes are provided on the positioning plate (530), and when the positioning pin (540) is inserted into three different positioning holes, the valve plate (400) can be positioned at a first position, a second position, or a third position.

10. The low resistance loss automatic closing three-way pipe for local ventilation fan according to claim 1, characterized in that: It also includes a sealing ring, which is arranged in the three-way body (100) and is used to seal the connection between the valve plate (400) and the three-way body (100).

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