Negative pressure fan

Abstract

The invention discloses a negative pressure fan which comprises an air gathering barrel, an air guide cover and a ventilation butterfly valve. A support is arranged on the inner wall of the air gathering barrel and connected with a motor, and a plurality of fan blades are arranged on the motor. The air gathering barrel is of a hollow barrel-shaped structure; an opening in one end of the wind gathering barrel is spliced with the wind scooper; an opening in the other end of the air gathering barrel is spliced with the ventilation butterfly valve; and the ventilation butterfly valve is provided with a beveled cylindrical structure. An opening in one end of the air gathering barrel is spliced with the air guide cover, an opening in the other end of the air gathering barrel is spliced with the ventilation butterfly valve, and a splicing installation mode is adopted, so that installation and maintenance are convenient. When the ventilation butterfly valve is opened, air flows through the air gathering barrel through the air guide cover, the motor and the support are installed on the inner wall of the air gathering barrel, and the working efficiency of the negative pressure fan is improved. The ventilation butterfly valve can be closed through the gravity of the ventilation butterfly valve after the motor is closed through the oblique cylindrical structure, so that the air tightness of the ventilation butterfly valve is improved while the efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of negative pressure fans, in particular to a negative pressure fan. Background Art

[0002] The ventilation butterfly valve in the negative pressure fan is mainly used to adjust the air volume and air pressure, and can be adjusted at any time according to production needs. The flow rate of the gas in the pipeline can be controlled by adjusting the opening and closing degree of the butterfly plate to achieve the purpose of stabilizing process production, reducing process energy consumption and ensuring safe production. The gas flow direction can also be changed by rotating the butterfly plate to make the gas flow direction relatively stable, reduce the resistance of the gas in the pipeline, and improve the ventilation efficiency. Effectively prevent gas backflow during operation to avoid accidents.

[0003] The negative pressure fan in the prior art not only has low ventilation efficiency, but also has some defects in the ventilation butterfly valve structure inside the negative pressure fan; when the fan stops running, the ventilation butterfly valve structure is not tight enough when closed, resulting in insufficient air tightness of the ventilation butterfly valve, causing gas to enter the room, making the air pressure fail to meet the requirements, affecting the ventilation effect. Summary of the invention

[0004] In order to overcome the above technical defects, the present invention provides a negative pressure fan and a ventilation butterfly valve.

[0005] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0006] The present invention discloses a negative pressure fan, comprising: an air collection tube, an air guide cover and a ventilation butterfly valve;

[0007] The inner wall of the wind conduit is provided with a bracket, the bracket is connected to a motor, and the motor is provided with a plurality of fan blades;

[0008] The wind collector is a hollow cylindrical structure;

[0009] One end opening of the wind collector is spliced ​​with the wind guide cover;

[0010] The other end opening of the air collector is spliced ​​with the ventilation butterfly valve.

[0011] Preferably, the ventilation butterfly valve comprises: the left butterfly plate and the right butterfly plate;

[0012] A valve stem, one side of which is hinged to the left butterfly plate, and the other side of which is hinged to the right butterfly plate;

[0013] A valve seat, wherein a plurality of H-shaped rods are arranged on the valve seat, and both ends of the valve rods are fixedly connected to the valve seat. A support column is arranged on the valve seat, and the support column is connected with the valve rod and the H-shaped rods to form a triangular structure;

[0014] Wherein, one side of the valve seat is an inclined surface, and the triangular structure is arranged on the inclined surface; a sealing ring is arranged around the upper surface of the valve seat.

[0015] Preferably, the front surfaces of the left butterfly plate and the right butterfly plate are both provided with connecting pieces;

[0016] The connecting piece is provided with a tension spring, and one end of the tension spring is connected to the valve stem.

[0017] The left butterfly plate and the right butterfly plate are symmetrical structures;

[0018] The left butterfly plate and the right butterfly plate both include a flat plate and a baffle;

[0019] One side of the plate is hinged to the valve stem, and the other side of the plate is provided with a U-shaped channel;

[0020] The U-shaped channel is connected to the baffle, and a boss adapted to the U-shaped channel is provided on one side of the baffle;

[0021] Wherein, a limiting plate is arranged on the valve stem, and a limiting platform is arranged on the back of the flat plate.

[0022] Preferably, one end of the H-shaped rod is connected to the wind cone, and the other end is connected to the second protective net;

[0023] The openings on both sides of the H-shaped rod are connected with arc-shaped plates;

[0024] The arc-shaped plates are connected to the H-shaped rods to present a trumpet shape.

[0025] Preferably, the air guide cover is provided with a streamlined structure, and a first protective net is provided on the air guide cover.

[0026] The bracket is provided with a wing-shaped structure.

[0027] Preferably, the wing-shaped structure comprises:

[0028] A U-shaped plate, one side of which is connected to the motor, and the other side of which is connected to the inner wall of the wind cone;

[0029] A flat cover plate, the inner surface of which is in contact with the U-shaped plate;

[0030] A wing-shaped cover plate, wherein two sides of the wing-shaped cover plate are provided with clamping channels adapted to two sides of the flat cover plate;

[0031] Wherein, the wing-shaped cover plate covers the flat cover plate, and the U-shaped plate and the wing-shaped cover plate are connected to form a cavity.

[0032] Compared with the prior art, the beneficial effects of the present invention are: a negative pressure fan, comprising: an air conduit, an air guide hood and a ventilation butterfly valve; a bracket is provided on the inner wall of the air conduit, the bracket is connected to a motor, and a plurality of fan blades are provided on the motor; the air conduit is a hollow cylindrical structure; an opening at one end of the air conduit is spliced ​​with the air guide hood; an opening at the other end of the air conduit is spliced ​​with the ventilation butterfly valve, and the ventilation butterfly valve 1 is provided with a truncated cylindrical structure.

[0033] The ventilation butterfly valve is used to control the flow rate and direction of air flow in the ventilation duct. By starting the motor, the ventilation butterfly valve can be adjusted from fully closed to fully open, so as to accurately manage the air circulation in the ventilation system. In the closed state, the ventilation butterfly valve can effectively seal to prevent air leakage; in the open state, the ventilation butterfly valve can ensure smooth air flow and meet the ventilation needs under different working conditions. The opening at one end of the wind chime is spliced ​​with the wind guide cover, and the opening at the other end of the wind chime is spliced ​​with the ventilation butterfly valve. The splicing installation method is adopted, which is easy to install and maintain. The air flows through the wind chime through the wind guide cover, and the motor and the bracket are installed on the inner wall of the wind chime, which improves the working efficiency of the negative pressure fan. The ventilation butterfly valve can be closed by its own gravity after the motor is turned off through the oblique cylindrical structure set, which improves the efficiency and the air tightness of the ventilation butterfly valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0035] Figure 1 It is a front schematic diagram of the structure of a negative pressure fan of the present invention;

[0036] Figure 2 It is a back schematic diagram of a structure of a negative pressure fan of the present invention;

[0037] Figure 3 It is a schematic diagram of the structure of a ventilation butterfly valve in a negative pressure fan of the present invention;

[0038] Figure 4 It is a structural schematic diagram of a ventilation butterfly valve in a negative pressure fan of the present invention from another perspective;

[0039] Figure 5 yes Figure 4 A magnified schematic diagram of part A;

[0040] Figure 6 It is a front view schematic diagram of the structure of a ventilation butterfly valve in a negative pressure fan of the present invention;

[0041] Figure 7 It is a schematic diagram of the back structure of a ventilation butterfly valve in a negative pressure fan of the present invention;

[0042] Figure 8It is a schematic diagram of a baffle component of a ventilation butterfly valve in a negative pressure fan of the present invention;

[0043] Fig. 9 It is a schematic diagram of a flat plate component of a ventilation butterfly valve in a negative pressure fan of the present invention;

[0044] Fig.10 It is a schematic diagram of the assembly structure of a ventilation butterfly valve and a wind cone in a negative pressure fan of the present invention;

[0045] Fig.11 yes Fig.10 A magnified schematic diagram of part B;

[0046] Fig.12 It is a side view of the assembly structure of a ventilation butterfly valve and an air cone in a negative pressure fan of the present invention;

[0047] Fig.13 It is a schematic diagram of the front and cross-sectional structure of an air guide cover in a negative pressure fan of the present invention;

[0048] Fig.14 It is a schematic diagram of the support structure of a negative pressure fan of the present invention;

[0049] Fig.15 It is a schematic diagram of parts of a bracket in a negative pressure fan of the present invention;

[0050] In the figure: 1-ventilation butterfly valve, 10-left butterfly plate, 11-right butterfly plate, 101-flat plate, 102-baffle, 103-connector, 104-tension spring, 105-limiting platform, 106-U-shaped channel, 107-boss, 108-buckle, 12-valve stem, 121-limiting plate, 122-fixing part, 13-valve seat, 131-sealing ring, 132-H-type rod, 133-support column, 134-upper surface, 135-arc plate, 14-front, 15-back, 2-wind duct, 20-bracket, 201-U-shaped plate, 202-flat cover, 203-wing cover, 21-motor, 22-fan blades, 3-wind guide cover, 31-first protective net, 32-second protective net, 33-mounting base plate. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0052] like Figure 1-Figure 15As shown, a negative pressure fan described in the present invention includes: an air collector 2, an air guide cover 3 and a ventilation butterfly valve 1, the inner wall of the air collector 2 is provided with a bracket 20, the bracket 20 is connected to a motor 21, and a plurality of fan blades 22 are provided on the motor 21; the air collector 2 is a hollow cylindrical structure; one end opening of the air collector 2 is spliced ​​with the air guide cover 3; the other end opening of the air collector 2 is spliced ​​with the ventilation butterfly valve 1, and the ventilation butterfly valve 1 is provided with an oblique cylindrical structure.

[0053] In one embodiment, if Figure 1-Figure 3 As shown, the air duct 2 is a hollow cylindrical structure, one end opening of the air duct 2 is spliced ​​with the air guide cover 3, and the other end opening of the air duct 2 is spliced ​​with the ventilation butterfly valve 1. A bracket 20 is provided at one end of the inner wall of the air duct 2 close to the air guide cover 3. The bracket 20 is used to fix the motor 21. Three fan blades 22 are installed on the side of the motor 21 close to the air guide cover 3. The gas flows through the air duct 2 through the air guide cover 3, which can cool the working motor 21 and extend the service life of the motor 21. The splicing installation method is easy to install and maintain.

[0054] Further, the ventilation butterfly valve 1 comprises: a left butterfly plate 10, a right butterfly plate 11, a valve stem 12 and a valve seat 13;

[0055] One side of the valve stem 12 is hinged to the left butterfly plate 10, and the other side of the valve stem 12 is hinged to the right butterfly plate 11;

[0056] A plurality of H-shaped rods 132 are arranged on the valve seat 13, both ends of the valve stem 12 are fixedly connected to the valve seat 13, a support column 133 is arranged on the valve seat 13, and the support column 133, the valve stem 12 and the H-shaped rods 132 are connected to form a triangular structure;

[0057] One side of the valve seat 13 is an inclined surface, and the triangular structure is arranged on the inclined surface; a sealing ring 131 is arranged around the upper surface 134 of the valve seat 13 .

[0058] like Figure 3-Figure 9 As shown, one side of the valve stem 12 is hinged to the left butterfly plate 10, and the other side of the valve stem 12 is hinged to the right butterfly plate 11, so that the ventilation butterfly valve 1 can be opened and closed. A plurality of H-shaped rods 132 are arranged on the valve seat 13, and both ends of the valve stem 12 are fixed on the valve seat 13. In one embodiment, the ventilation butterfly valve 1 is provided with an oblique cylindrical structure, and both ends of the valve stem 12 are fixedly connected to the H-shaped rods 132 by bolts. The H-shaped rods 132 are used to connect the ventilation butterfly valve 1 with the wind pipe 2, which is convenient for disassembly and assembly, and improves production efficiency.

[0059] In one embodiment, four H-shaped rods 132 are arranged at equal distances around the valve seat 13 on the valve seat 13, and both ends of the valve stem 12 are fixed on the valve seat 13. A support column 133 is provided on the valve seat 13, and the support column 133 is connected with the valve stem 12 and the H-shaped rod 132 to form a triangular structure. The support column 133 in the triangular structure fixes the valve stem 12 and the H-shaped rod 132, thereby improving the stability of the structure, avoiding excessive wind force and violent shaking caused by changes in the flow rate of the wind body during the process of starting and shutting down the fan, thereby improving the working efficiency of the negative pressure fan and extending the service life of the negative pressure fan.

[0060] In one embodiment, the ventilation butterfly valve 1 is provided with an oblique cylindrical structure, and the upper surface 134 of the valve seat 13 is an inclined surface, and an inclined surface with a slope is provided. When the fan is started, the wind force can quickly open the ventilation butterfly valve 1, thereby improving the performance of the fan. When the negative pressure fan is stopped, the ventilation butterfly valve 1 is in a folded state, the motor 21 stops running, and the ventilation butterfly valve 1 closes the ventilation butterfly valve 1 with the assistance of its own weight and the tension spring 104. Magnets are provided around the valve seat 13 to absorb the left butterfly plate 10 and the right butterfly plate 11, which will not loosen easily, thereby improving the air tightness of the ventilation butterfly valve 1. The highly sealed ventilation butterfly valve 1 structure can prevent external airflow from penetrating into the room, improve the negative pressure ventilation effect in the room, and avoid the original air pressure in the room not being reached, resulting in insufficient local ventilation volume, which affects the use effect of the negative pressure fan. Extend the service life of the negative pressure fan.

[0061] The sealing ring 131 is made of urethane rubber, which has the highest wear resistance among all rubbers and good buffering and shock absorption. It has good oil resistance and chemical resistance. When the ventilation butterfly valve 1 is closed, the sealing ring 131 can ensure that there is no air circulation in the ventilation butterfly valve 1. It has the advantages of good strength, high elasticity, high wear resistance, and aging resistance, which improves the airtightness of the ventilation butterfly valve and can extend the service life of the ventilation butterfly valve.

[0062] Furthermore, a connecting piece 103 is disposed on the front side 14 of the left butterfly plate 10 and the right butterfly plate 11 ; a tension spring 104 is disposed on the connecting piece 103 , and one end of the tension spring 104 is connected to the valve stem 12 .

[0063] It is understandable that if Figure 7 As shown, a connector 103 is provided on the front face 14 of the left butterfly plate 10 and the right butterfly plate 11, and a tension spring 104 connects the valve stem 12 and the connector 103. In one embodiment, after the flat plate 101 and the baffle plate 102 are spliced, the connector 103 is fixed to the front face 14 of the flat plate 101 and the baffle plate 102, and fixing members 122 for fixing the tension spring 104 are provided on both sides of the valve stem 12, and the tension spring 104 is provided on the connector 103, and the connector 103 is provided with a buckle 108 for fixing the tension spring 104, one end of the tension spring 104 is connected to the buckle 108, and the other end is connected to the fixing member 122 provided on the valve stem 12.

[0064] When the fan is turned on, the left butterfly plate 10 and the right butterfly plate 11 are in a folded open state, and the tension spring 104 is in a tensioned state. When the fan is turned off, the tension spring 104 contracts under the action of elastic force, and the left butterfly plate 10 and the right butterfly plate 11 are flattened from the folded state. At this time, the left butterfly plate 10 and the right butterfly plate 11 are in a closed state. Using the tension spring 104 to close the left butterfly plate 10 and the right butterfly plate 102 has high efficiency, high sealing, simple installation, and improved production efficiency.

[0065] Furthermore, the left butterfly plate 10 and the right butterfly plate 11 are symmetrical structures; the left butterfly plate 10 and the right butterfly plate 11 both include a flat plate 101 and a baffle 102; one side of the flat plate 101 is hinged to the valve stem 12, and the other side of the flat plate 101 is provided with a U-shaped channel 106; the U-shaped channel 106 is connected to the baffle 102, and one side of the baffle 102 is provided with a boss 107 adapted to the U-shaped channel 106; a limiting platform 105 is provided on the back side 15 of the flat plate 101.

[0066] It is understandable that if Figure 4-Figure 6 As shown, the left butterfly plate 10 and the right butterfly plate 11 are symmetrical structures. In one embodiment, the left butterfly plate 10 and the right butterfly plate 11 are both spliced ​​by a flat plate 101 and a baffle 102 to form a semicircular structure, one side of the flat plate 101 of the left butterfly plate 10 is hinged to the valve stem 12, and the other side of the valve stem 12 is hinged to one side of the flat plate 101 of the right butterfly plate 11, and the left butterfly plate 10 and the right butterfly plate 11 can be turned over by the valve stem 12.

[0067] The valve stem 12 is fixed on the valve seat 13, and a limit plate 121 is provided on the valve stem 12, and a limit platform 105 is provided on the back side 15 of the flat plate 101. In this embodiment, when the fan is started, the back side 15 of the left butterfly plate 10 and the right butterfly plate 11 begin to fold until the limit platform 105 abuts against the limit plate 121 on the valve stem 12. At this time, the left butterfly plate 10 and the right butterfly plate 11 are in a folded open state.

[0068] Furthermore, one end of the H-shaped rod 132 is connected to the wind tube 2, and the other end is connected to the second protective net 32; both side openings of the H-shaped rod 132 are connected to arc plates 135; the arc plates 135 are connected to the H-shaped rod 132 to form a trumpet shape.

[0069] It is understandable that if Figure 10-12As shown, in one embodiment, every two arc plates 135 are spliced ​​into a trumpet shape through an H-shaped rod 132, and notches are set on both sides of the H-shaped rod 132. One side of the first arc plate 135 is embedded in a notch of the H-shaped rod 132, and one side of the second arc plate 135 is embedded in another notch of the H-shaped rod 132. The other end of the second arc plate 135 is embedded in a notch on one side of the second H-shaped rod 132, until the arc plate 135 and the H-shaped rod 132 are spliced ​​and connected to form a trumpet shape, and the H-shaped rod 132 and the arc plate 135 are fixed with rivets. The trumpet shape is conducive to the efficient exhaust of the fan, and the negative pressure fan can more effectively concentrate and exhaust air, thereby improving the efficiency of the negative pressure fan. Compared with the traditional negative pressure fan, the trumpet shape can make the fan generate less noise during operation.

[0070] One end of the H-shaped rod 132 is connected to the air collector 2, and the other end is connected to the second protection net 32. The second protection net 32 ​​is arranged at the air outlet of the negative pressure fan.

[0071] In this embodiment, the H-shaped rod 132 is made of stainless steel. Stainless steel has good corrosion resistance, heat resistance, low temperature strength and mechanical properties; it has good hot processing properties such as stamping and bending, and there is no heat treatment hardening phenomenon. The structure of the ventilation butterfly valve 1 is more stable and not easily deformed by external force trauma. The second protective net 32 ​​made of stainless steel is provided with a regularly arranged grid structure and is installed at the air outlet of the negative pressure fan. It can play a role of double-layer safety protection for the internal structure of the negative pressure fan. Make the structure more stable and extend the service life of the fan.

[0072] Furthermore, the air guide cover 3 is provided with a streamlined structure, and a first protective net 31 is provided on the air guide cover 3; and the bracket 20 is provided with a wing-shaped structure.

[0073] like Fig.13 As shown, the air guide hood 3 is provided with a streamlined structure, and the shape of the streamlined structure presents a smooth curve. The cross-sectional profile of the air guide hood 3 is arc-shaped, and there are no protruding edges and tips on the surface, which can better contact with the gas and reduce resistance. One side of the air guide hood 3 is spliced ​​with one side of the wind conduit 2. When the negative pressure fan is turned on, the gas enters the interior along the smooth shape curve in the streamlined structure of the air guide hood 3. The streamlined structure with extremely high fluid mechanics performance can reduce the resistance of air flow and improve the efficiency of the fan.

[0074] In this embodiment, there is a first protective net 31 at the air inlet of the air guide cover 3. The first protective net 31 is made of stainless steel and has good corrosion resistance, heat resistance, low temperature strength and mechanical properties; it has good thermal processing properties such as stamping and bending, and there is no heat treatment hardening phenomenon. In one embodiment, the first protective net 31 is made of stainless steel. It plays a role of safety protection. The first protective net 31 set on the air guide cover 3 can prevent external objects, impurities or animals from entering the interior of the negative pressure fan, avoid damaging the blades 22 and motor 21 or other components of the negative pressure fan, and protect the safe operation of the fan.

[0075] The bracket 20 is provided with an organic wing-shaped structure to enable the fan to achieve low wind resistance. In this embodiment, the bracket 20 is made of stainless steel, which has high strength and corrosion resistance. The bracket 20 is bolted as a whole for easy installation and maintenance. The bracket 20 plays a role in dustproof, waterproof and low wind resistance, and can also protect the cables, thereby extending the service life of the fan.

[0076] Further, such as Figure 14-15 As shown, the wing-shaped structure includes a U-shaped plate 201, a flat cover plate 202 and a wing-shaped cover plate 203; one side of the U-shaped plate 201 is connected to the motor 3, and the other side of the U-shaped plate 201 is connected to the inner wall of the wind chime 2; the inner surface of the flat cover plate 202 is fitted with the U-shaped plate 201; both sides of the wing-shaped cover plate 203 are provided with clamping channels 204 adapted to the two sides of the flat cover plate 202; the wing-shaped cover plate 203 covers the flat cover plate 202; the U-shaped plate 201 and the wing-shaped cover plate 203 are connected to form a cavity.

[0077] In order to optimize the airflow and improve the working efficiency of the fan, in the present invention, specifically, the wing-shaped structure is used to improve the air flow efficiency of the fan. The specific structure includes a U-shaped plate 201, a flat cover plate 202 and a wing-shaped cover plate 203, and the specific configuration is as follows:

[0078] The U-shaped plate 201 is a metal plate with a U-shaped cross section, one side of which is connected to the motor 21. The motor 21 is fixedly connected to the negative pressure fan through the U-shaped plate 201 to drive the negative pressure fan to work. The other side of the U-shaped plate 201 is fixedly connected to the inner wall of the wind tube 2 to form a supporting structure to ensure the overall stability of the wing-shaped structure.

[0079] The inner surface of the flat cover plate 202 fits with the upper surface of the U-shaped plate 201 to play a sealing role, reduce the overall cross-sectional area of ​​the bracket 20, make the airflow pass more smoothly when the fan is started, and reduce the resistance of the airflow.

[0080] The airfoil cover plate 203 has a streamlined shape, which can guide the airflow more effectively to reduce air resistance, thereby improving the overall efficiency of the fan.

[0081] The two sides of the wing-shaped cover plate 203 are provided with clamping tracks 204 adapted to the two sides of the flat cover plate 202. The clamping tracks 204 are designed to adapt to and fix the connection between the wing-shaped cover plate 203 and the flat cover plate 202 to ensure that the structure is stable and not easy to loosen.

[0082] The wing-shaped cover plate 203 covers the top of the flat cover plate 202, and forms a cavity structure by connecting with the U-shaped plate 201. The cavity can hide the cable of the motor 21, play the role of dustproof, waterproof and low wind resistance, and at the same time can protect the cable of the motor 21, thereby extending the service life of the negative pressure fan.

[0083] Furthermore, a mounting base plate 33 is provided on the outer wall surface of the air guide cover 3 for fixing the negative pressure fan.

[0084] It is understandable that if Figure 1-Figure 2 As shown, a mounting base plate 33 is provided at the connection between the outer wall surface of the air guide cover 3 and the wind cone 2. The mounting base plate 33 can fix the negative pressure fan on a wall or an object.

[0085] The working principle of a negative pressure fan described in the present invention is:

[0086] The air duct 2 is a hollow cylindrical structure. One end opening of the air duct 2 is spliced ​​with the air guide cover 3, and the other end opening of the air duct 2 is spliced ​​with the ventilation butterfly valve 1. A bracket 20 is provided at one end of the inner wall of the air duct 2 close to the air guide cover 3. The bracket 20 is used to fix the motor 21. The motor 21 is installed close to the air guide cover 3, which extends the channel for gas flow and improves the working efficiency of the negative pressure fan.

[0087] The bracket 20 is provided with an organic wing-shaped structure to enable the fan to achieve low wind resistance. The wing-shaped structure of the bracket 20 includes: a U-shaped plate 201, a flat cover plate 202 and a wing-shaped cover plate 203. The U-shaped plate 201 is a metal plate with a U-shaped cross-section, one side of which is connected to the motor 21. The motor 21 is fixedly connected to the negative pressure fan through the U-shaped plate 201 to drive the negative pressure fan to work. The inner surface of the flat cover plate 202 fits the upper surface of the U-shaped plate 201 to play a sealing role, reduce the overall cross-sectional area of ​​the bracket 20, make the airflow pass more smoothly when the negative pressure fan is started, and reduce the resistance of the airflow. The wing-shaped cover plate 203 has a streamlined shape, which can more effectively guide the airflow to reduce air resistance, thereby improving the overall efficiency of the fan. The two sides of the wing-shaped cover plate 203 are provided with clamping tracks 204 adapted to the two sides of the flat cover plate 202. The clamping tracks 204 are designed to adapt to and fix the connection between the wing-shaped cover plate 203 and the flat cover plate 202 to ensure that the structure is stable and not easy to loosen.

[0088] The air guide hood 3 is provided with a streamlined structure, and the shape of the streamlined structure presents a smooth curve. The cross-sectional profile of the air guide hood 3 is arc-shaped, and there are no protruding edges and tips on the surface, which can better contact with the gas and reduce resistance. There is a first protective net 31 at the air inlet of the air guide hood 3. The first protective net 31 can prevent external objects, impurities or animals from entering the interior of the negative pressure fan, avoid damaging the blades 22 and motor 21 or other components of the negative pressure fan, and protect the safe operation of the fan. The gas flows through the air guide hood 3 through the wind tube 2, passes through the ventilation butterfly valve 1 and flows out of the negative pressure fan.

[0089] One side of the valve stem 12 is hinged to the left butterfly plate 10, and the other side of the valve stem 12 is hinged to the right butterfly plate 11, so that the ventilation butterfly valve 1 can be opened and closed. The two ends of the valve stem 12 are fixedly connected to the H-shaped rod 132 by bolts. The H-shaped rod 132 is used to connect the ventilation butterfly valve 1 to the wind duct 2, which is convenient for disassembly and assembly, and improves production efficiency. A support column 133 is provided on the valve seat 13, and the support column 133 is connected to the valve stem 12 and the H-shaped rod 132 to form a triangular structure. In the triangular structure, the support column 133 fixes the valve stem 12 and the H-shaped rod 132, which improves the stability of the structure, avoids excessive wind force during the process of starting and closing the fan, and avoids violent shaking caused by changes in the flow rate of the wind body, thereby improving the working efficiency of the negative pressure fan and extending the service life of the negative pressure fan.

[0090] When the negative pressure fan is turned on, the left butterfly plate 10 and the right butterfly plate 11 are in a folded open state, and the tension spring 104 is in a tensioned state. When the negative pressure fan is turned off, the ventilation butterfly valve 1 is provided with an oblique cylindrical structure, which can shrink under its own gravity and the elastic force of the tension spring 104, and the left butterfly plate 10 and the right butterfly plate 11 are flattened from the folded state. At this time, the left butterfly plate 10 and the right butterfly plate 11 are in a closed state. The oblique cylindrical structure and the elastic force of the tension spring 104 are used to close the left butterfly plate 10 and the right butterfly plate 102. The upper surface 134 of the valve seat 13 is provided with a sealing ring 131 around it. The sealing ring 131 has a buffering effect after the left butterfly plate 10 and the right butterfly plate 11 are flattened. The sealing ring 131 can also ensure that there is no air circulation inside the negative pressure fan after the ventilation butterfly valve 1 is closed, thereby improving the airtightness of the ventilation butterfly valve and extending the service life of the ventilation butterfly valve. While improving efficiency, the airtightness of the ventilation butterfly valve is also improved.

[0091] Every two arc-shaped plates 135 are spliced ​​into a trumpet shape through an H-shaped rod 132, which is conducive to the efficient exhaust of the fan. The negative pressure fan can more effectively concentrate and exhaust air, thereby improving the efficiency of the negative pressure fan. One end of the H-shaped rod 132 is connected to the wind tube 2, and the other end is connected to the second protective net 32. The second protective net 32 ​​is provided with a regularly arranged grid structure and is installed at the air outlet of the negative pressure fan. It can play a role in double-layer safety protection of the internal structure of the negative pressure fan, making the structure more stable and extending the service life of the fan.

[0092] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A negative pressure fan, characterized in that: include: A wind chime (2), wherein a bracket (20) is disposed on the inner wall of the wind chime (2), the bracket (20) is connected to a motor (21), and a plurality of fan blades (22) are disposed on the motor (21); The wind collector (2) is a hollow cylindrical structure; An air guide cover (3), one end opening of the air collection tube (2) is spliced ​​with the air guide cover (3); A ventilation butterfly valve (1), wherein the other end opening of the air collecting tube (2) is spliced ​​with the ventilation butterfly valve (1), and the ventilation butterfly valve (1) is provided with an oblique cylindrical structure.

2. A negative pressure fan according to claim 1, characterized in that: The ventilation butterfly valve comprises: A left butterfly plate (10) and a right butterfly plate (11); A valve stem (12), one side of the valve stem (12) being hinged to the left butterfly plate (10), and the other side of the valve stem (12) being hinged to the right butterfly plate (11); A valve seat (13), wherein a plurality of H-shaped rods (132) are arranged on the valve seat (13), both ends of the valve stem (12) are fixedly connected to the valve seat (13), a support column (133) is arranged on the valve seat (13), and the support column (133), the valve stem (12) and the H-shaped rods (132) are connected to form a triangular structure; One side of the valve seat (13) is an inclined surface, and the triangular structure is arranged on the inclined surface; a sealing ring (131) is arranged around the upper surface (134) of the valve seat (13).

3. A negative pressure fan according to claim 2, characterized in that: Connecting pieces (103) are provided on the front faces (14) of the left butterfly plate (10) and the right butterfly plate (11); The connecting member (103) is provided with a tension spring (104), and one end of the tension spring (104) is connected to the valve stem (12).

4. A negative pressure fan according to claim 2, characterized in that: The left butterfly plate (10) and the right butterfly plate (11) are symmetrical structures. The left butterfly plate (10) and the right butterfly plate (11) both include a flat plate (101) and a baffle (102); One side of the flat plate (101) is hinged to the valve stem (12), and the other side of the flat plate (101) is provided with a U-shaped channel (106); The U-shaped channel (106) is connected to the baffle (102), and a boss (107) adapted to the U-shaped channel (106) is provided on one side of the baffle (102); Wherein, a limiting plate (121) is provided on the valve stem (12), and a limiting platform (105) is provided on the back side (15) of the flat plate (101).

5. A negative pressure fan according to claim 2, characterized in that: One end of the H-shaped rod (132) is connected to the wind cone (2), and the other end is connected to the second protection net (32); The openings on both sides of the H-shaped rod (132) are connected to arc-shaped plates (135); The arc-shaped plates (135) are connected to the H-shaped rods (132) to form a trumpet shape.

6. A negative pressure fan according to claim 1, characterized in that: The wind guide cover (3) is provided with a streamlined structure, and a first protective net (31) is provided on the wind guide cover (3). The support (20) is provided with a wing-shaped structure.

7. A negative pressure fan according to claim 6, characterized in that: The wing-shaped structure comprises: A U-shaped plate (201), one side of the U-shaped plate (201) being connected to the motor (21), and the other side of the U-shaped plate (201) being connected to the inner wall of the wind cone (2); A flat cover plate (202), the inner surface of the flat cover plate (202) being in contact with the U-shaped plate (201); A wing-shaped cover plate (203), wherein two sides of the wing-shaped cover plate (203) are provided with clamping tracks (204) adapted to two sides of the flat cover plate (202); The wing-shaped cover plate (203) covers the flat cover plate (202), and the U-shaped plate (201) and the wing-shaped cover plate (203) are connected to form a cavity.

8. The negative pressure fan according to claim 1, characterized in that: The outer wall surface of the air guide cover (3) is provided with a mounting base plate (33) for fixing the negative pressure fan.

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