A ventilation fan applied to the prevention of occupational chemical gas poisoning in public health

Abstract

The application relates to the technical field of ventilation fans, and discloses a ventilation fan applied to public health prevention of occupational chemical gas poisoning, which comprises a shell, a bearing connected to one side of the shell through a bearing sleeve, a motor transmission connected with an impeller shaft, the impeller shaft penetrating through the bearing and connected with an impeller, the bearing sleeve fixedly connected with a mounting disc, the mounting disc movably connected with a convex pipe with a plurality of protrusions through a mounting bearing, and the mounting disc fixedly connected with a concave pipe with a groove. The ventilation fan applied to public health prevention of occupational chemical gas poisoning takes the labyrinth sealing assembly as a whole, only needs to be inserted into a containing cavity at the end of the bearing sleeve, and corresponding bolts are tightened, so that installation is completed. The installation mode reduces the requirement for installation precision, and further improves the reliability of sealing. Meanwhile, the vibration of the impeller shaft can be isolated, and the influence of vibration on the labyrinth passage when the fan rotates is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of ventilation fan technology, and in particular to a ventilation fan used in public health prevention of occupational chemical gas poisoning. Background Technology

[0002] In the field of public health, the prevention of occupational chemical gas poisoning is of paramount importance, directly impacting workers' health, social stability, and workplace safety. Therefore, ventilation systems must be strictly implemented in relevant workplaces, and the performance of ventilation fans, as key components of these systems, is of utmost importance.

[0003] Shaft clearance leakage is a common problem during the operation of ventilation fans. Specifically, the medium can leak from the high-pressure side to the low-pressure side or the outside environment through the gap between the shaft and the casing, which can potentially cause the concentration of toxic gases in the environment to exceed the standard value. Therefore, reducing the shaft clearance leakage of ventilation fans is particularly necessary.

[0004] A backflow seal is a sealing method that uses a labyrinth seal structure on the outside of the shaft clearance. In this structure, a backflow cavity is formed between the shaft clearance and the sealing structure. Utilizing the pressure gradient inside the fan, leaked gas is guided back to the low-pressure area of ​​the fan through a backflow pipe, thereby reducing gas leakage to the outside. Typically, backflow seals are low-cost and easy to maintain due to the absence of friction components, and they can effectively control shaft clearance leakage, keeping it below standard values.

[0005] However, due to the extremely narrow gaps created by the labyrinth seal, improper assembly or significant vibration during fan operation can damage the labyrinth seal. Therefore, this sealing method places high demands on installation accuracy and the smoothness of fan operation. In reality, however, fan installation and maintenance are usually handled by the customer's personnel. Given the varying technical capabilities of different companies, substandard labyrinth seal installation and improper installation of the fan shaft and motor shaft, leading to excessive fan vibration, are common occurrences. This significantly reduces the reliability of the backflow seal. Summary of the Invention

[0006] This application proposes a ventilation fan for public health prevention of occupational chemical gas poisoning. The labyrinth sealing assembly is a whole unit, which can be installed simply by inserting it into the receiving cavity at the end of the bearing sleeve and tightening the corresponding bolts. At the same time, it can isolate the vibration of the impeller shaft and effectively reduce the impact of the vibration of the fan on the labyrinth channel when it rotates.

[0007] To achieve the above objectives, this application adopts the following technical solution: a ventilation fan for public health prevention of occupational chemical gas poisoning, comprising a housing and a motor. The housing has an inlet and an outlet. A bearing is connected to one side of the housing via a bearing sleeve. An impeller shaft is driven by the motor. The impeller shaft passes through the bearing and is connected to an impeller. A mounting plate is fixedly connected to the bearing sleeve. A convex tube with several protrusions is movably connected to the mounting plate via a mounting bearing. A concave tube with grooves is fixedly connected to the mounting plate. The grooves and protrusions correspond one-to-one and cooperate to form a labyrinth channel. Both the convex and concave tubes are coaxial with the impeller shaft. The end of the concave tube is pressed against the inner end face of the bearing sleeve to achieve end face sealing. A sealing flange is welded to the side wall of the impeller shaft. The end of the convex tube is sealed and fastened to the sealing flange via a flexible closed cylinder. The return chamber is connected to the inlet via a return pipe.

[0008] Furthermore, the protrusion is an annular convex disk, and the groove is an annular groove. The convex disk and the annular groove form a radial labyrinth channel, and the top of the groove and the top of the concave disk fit together to form an expansion cavity.

[0009] Furthermore, the concave tube includes a concave ring, a closing ring, a fastening rod, and a mounting cylinder. The concave ring is composed of two semi-circular parts, which are fixed by fastening bolts. The closing ring is located between two adjacent concave rings, and the two adjacent concave rings are spaced apart by a convex plate. The fastening rod passes through each concave ring and the closing ring, fastening them into a whole to form a groove assembly. The inner wall of the mounting cylinder has an inner edge, and the inward end of the mounting cylinder is threadedly connected to a clamping tube. The outer wall of the sealing assembly is close to the inner wall of the mounting cylinder and is located between the inner edge and the clamping tube. The groove assembly is clamped by the inner edge and the clamping tube. The mounting cylinder is threadedly connected to the inner wall of the mounting plate.

[0010] Furthermore, the closing ring can be stretched radially but cannot be compressed axially. When the fastening rod axially tightens the concave ring and the closing ring, the spacer bar can ensure that the degree of compression of each closing ring is consistent, thereby ensuring that the overall dimensions of the groove assembly and the grooves on it are consistent.

[0011] Furthermore, an adjustment pad is provided between the mounting cylinder and the mounting plate, and an adjustment ring is provided on the innermost side of the convex tube. When the gap between the adjustment ring and the groove assembly reaches the set value, the gap of the labyrinth channel is the optimal value. The convex tube, convex plate and adjustment ring are made of plastic and are integrally molded by injection molding.

[0012] Furthermore, sealing rings are provided between the closing ring and the mounting cylinder, and between the mounting cylinder and the inner wall of the bearing sleeve.

[0013] Furthermore, 2-3 of the aforementioned closed rings are combined into a whole and fitted onto the corresponding concave ring.

[0014] Furthermore, the concave ring is hollow and has several through holes on its inner wall. When particulate matter flows with air through the concave ring, it enters the interior of the concave ring through the through holes, preventing it from damaging the labyrinth passage. At the same time, the concave ring can also serve as part of the expansion cavity, increasing its volume and enhancing the labyrinth passage effect. The concave ring can be integrally molded from plastic.

[0015] The beneficial effects of this invention are as follows:

[0016] This application provides a ventilation fan for public health prevention of occupational chemical gas poisoning. The fan achieves sealing at the bearing sleeve end through a labyrinth seal assembly and a return pipe. During installation, the labyrinth seal assembly is treated as a single unit; it is simply inserted into the receiving cavity at the bearing sleeve end and the corresponding bolts are tightened to achieve end-face sealing and installation of the labyrinth seal assembly. This installation method reduces the requirements for installation precision, thereby improving the reliability of the seal and effectively preventing excessive leakage of harmful gases from the shaft clearance.

[0017] Furthermore, both the convex and concave tubes are mounted on the bearing sleeve housing, and a closed cylinder enables flexible transmission between the convex tube and the impeller shaft. This design isolates vibrations between the impeller shaft and the convex tube, transforming the vibrations generated by the impeller shaft rotation from direct transmission to the convex tube to first passing through the bearing sleeve housing, then from the housing to the mounting bearing, and finally to the convex and concave tubes. On one hand, the vibration intensity is significantly reduced after being constrained by the fasteners on the housing; on the other hand, the vibrations of the convex and concave tubes remain synchronized, effectively reducing the impact of fan vibrations on the labyrinth channel, further improving the reliability and service life of the seal. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort:

[0019] Figure 1 This is a schematic diagram of the labyrinth sealing assembly in this invention;

[0020] Figure 2 This is a schematic diagram of the present invention;

[0021] Figure 3 This is a schematic diagram of the ventilation system used in this invention;

[0022] Figure 4 For the present invention Figure 1 Enlarged view of A in the middle;

[0023] Figure 5 This is a schematic diagram of the convex tube and the concave tube in this invention;

[0024] Figure 6 This is a schematic diagram of the concave ring in this invention.

[0025] In the diagram: 1. Motor; 2. Housing; 3. Inlet; 4. Outlet; 5. Bearing; 6. Bearing sleeve; 7. Labyrinth seal assembly; 71. Convex tube; 72. Convex disc; 73. Concave tube; 731. Concave ring; 732. Sealing ring; 733. Fastening rod; 734. Mounting cylinder; 735. Inner edge; 736. Clamping tube; 737. Adjusting shim; 738. Sealing block; 739. Sealing ring; 74. Sealing cylinder; 75. Mounting bearing; 76. Mounting plate; 77. Sealing flange; 78. Adjusting ring; 8. Impeller shaft; 9. Return chamber; 10. Return pipe; 11. Internal fan; 12. Inlet hood; 13. Treatment tank. Detailed Implementation

[0026] 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.

[0027] Please see Figure 2 and Figure 3 A ventilation fan for public health prevention of occupational chemical gas poisoning includes a housing 2 and a motor 1. The housing 2 has an inlet 3 and an outlet 4. An impeller shaft 8 is connected to one side of the housing 2 via a bearing 5. A bearing sleeve 6 is provided on one side of the motor 1, and a bearing 5 is installed inside the bearing sleeve 6. An impeller is connected to the impeller shaft 8. The rotation of the impeller causes airflow to be drawn in from the inlet 3 and blown out from the outlet 4. The impeller shaft 8 is fixedly connected to the output shaft of the motor 1 via a flange. The inlet 3 is connected to an inlet hood 12 via a ventilation duct. An internal fan 11 is provided between the inlet hood 12 and the inlet 3. The outlet 4 is connected to a treatment tank 13. According to actual needs, the treatment tank 13 can be provided with a spray chamber and an activated carbon adsorption chamber, which are used to neutralize toxic gases or adsorb toxic gases, respectively.

[0028] Please see Figure 1The labyrinth sealing assembly 7 includes a mounting plate 76, which is fixed to the end face of the bearing sleeve 6 by fastening bolts. The end face of the bearing sleeve 6 has corresponding flanges and mounting holes. The mounting plate 76 is movably connected to a convex tube 71 with several convex discs 72 via a mounting bearing 75. The mounting plate 76 is fixedly connected to a concave tube 73 with an annular groove, the groove corresponding one-to-one with the convex discs 72. Both the convex tube 71 and the concave tube 73 are coaxial with the impeller shaft 8, with the convex tube 71 located inside the concave tube 73. The end is provided with a receiving cavity to accommodate the concave tube 73 and the convex tube 71. The end of the concave tube 73 is sealed to the inner end face of the receiving cavity by a sealing block 738. The concave tube 73 and the bearing sleeve 6 are statically sealed, which has high reliability. There are gaps between the inner wall of the concave tube 73 and the convex tube 71, as well as between the convex plate 72 and the groove. The convex plate 72 and the groove cooperate to form a labyrinth channel. The top of the groove and the top of the concave plate cooperate to form an expansion cavity. The end of the convex tube 71 is fixedly connected to a closed cylinder 74. Both ends of the closed cylinder 74 and the end of the convex tube 71 are equipped with clamping discs. To facilitate the installation of the clamping discs, each clamping disc consists of two semi-circular rings. A sealing flange 77 is welded to the side wall of the impeller shaft 8. One end of the closed cylinder 74 is fixedly connected to the convex tube 71 through the clamping disc, and the other end of the closed cylinder 74 is fixedly connected to the sealing flange 77 through the clamping disc. The clamping disc is equipped with a rubber gasket for sealing. The closed cylinder 74 is made of flexible material, and the impeller shaft 8 can drive the convex tube 71 synchronously through the closed cylinder 74. While rotating, it can isolate the vibration of the impeller shaft 8. Since the inner end face of the concave tube 73 and the gap between the convex tube 71 and the impeller shaft 8 are sealed, the gas leaking through the shaft gap can only flow in the labyrinth channel. A return cavity 9 is formed between the labyrinth sealing assembly 7 and the bearing 5. The return cavity 9 is connected to the return pipe 10. The other end of the return pipe 10 is connected to the suction port 3. When the fan is running, most of the gas in the return cavity 9 flows back to the suction port 3, and only a small amount of gas flows out through the labyrinth channel.

[0029] In this embodiment, a radial labyrinth is formed by the radial engagement of an annular groove and a convex tube 71. In other embodiments, an axial labyrinth can also be formed by the axial engagement of a cylindrical groove and a cylindrical protrusion. However, since the bearing has a clearance, there is radial vibration during operation, which has a greater impact on the axial labyrinth than on the radial labyrinth. Therefore, the radial labyrinth in this embodiment is a relatively preferred solution.

[0030] The gaps between the labyrinth seal assembly 7 and the bearing sleeve 6, as well as the gap between the labyrinth seal assembly 7 and the impeller shaft 8, are sealed at both ends of the labyrinth seal assembly 7 by end face seals. At the same time, the convex tube 71 is fixed by the mounting plate 76 through the mounting bearing 75, and the concave tube 73 is fixed by the mounting plate 76, thus isolating it from the rotating impeller shaft 8. On the one hand, the labyrinth seal assembly 7 can be installed as a whole, directly mounted on the bearing sleeve 6 through end face fit during installation, without the need to adjust the fit clearance, reducing installation requirements and minimizing installation non-compliance. On the other hand, the labyrinth seal assembly 7 is relatively isolated from the impeller shaft 8, so the vibration of the impeller shaft 8 is not directly transmitted to the labyrinth seal assembly 7. Instead, the vibration transmitted through the bearing 5 to the bearing sleeve 6 and then through the mounting plate 76 to the convex tube 71 and the concave tube 73 is restrained by the fasteners on the housing 2, and the vibration intensity is greatly reduced. At the same time, since both the convex tube 71 and the concave tube 73 are connected to the mounting plate 76, their vibration is synchronized, which also reduces the impact of vibration and effectively overcomes the impact of vibration during fan operation. The gap of the labyrinth can be set to a smaller size.

[0031] The labyrinth sealing assembly 7, as a whole, increases the difficulty of production and the cost of use. For details, please refer to [link / reference needed]. Figure 1 , Figure 4 and Figure 5The concave tube 73 includes a concave ring 731, a closing ring 732, a fastening rod 733, and a mounting sleeve 734. The concave ring 731 consists of two semi-circular parts, which are fixed by fastening bolts. The concave ring 731 is fitted onto the convex disc 72. The closing ring 732 is located between two adjacent concave rings 731, with a gap of one convex disc 72 between adjacent concave rings 731. That is, the concave ring 731 fits onto one convex disc 72, and the groove formed by the concave ring 731 and the closing ring 732 corresponds to the next convex disc 72. The fastening rod 733 passes through each concave ring 731 and the closing ring 732. They are fastened together to form a groove assembly. The closing ring 732 can be stretched radially but cannot be compressed axially. Therefore, the closing ring 732 can be made of an elastic material. To prevent the bearing from being compressed, several axial spacers are embedded in the closing ring 732. The closing ring 732 is elastic. When the fastening rod 733 axially tightens the concave ring 731 and the closing ring 732, the spacers ensure that the degree of compression of each closing ring 732 is consistent, thereby ensuring that the overall groove assembly and the dimensions of its grooves are consistent. The inner wall of the mounting cylinder 734 has an inner edge 735. One inward-facing end of the mounting cylinder 734 is threadedly connected to a clamping tube 736. The outer wall of the groove assembly is pressed against the inner wall of the mounting cylinder 734 and is located between the inner edge 735 and the clamping tube 736. The groove assembly is clamped by the inner edge 735 and the clamping tube 736. In this embodiment, the groove assembly is clamped by a clamping closing ring 732. In other embodiments, the groove assembly can also be clamped by a clamping concave ring 731. The mounting cylinder 734 is threadedly connected to the inner wall of the mounting plate 76, and an adjusting shim 737 is provided at the connection point. The thickness of the adjusting shim 737 is adjusted to adjust the relative position of the mounting cylinder 734 to the convex tube 71. The position of the groove assembly relative to the convex plate 72 is adjusted. To facilitate observation of whether the gap of the maze channel is appropriate, an adjustment ring 78 is provided on the innermost side of the convex tube 71. Since the groove assemblies are of the same size, the gap between the side wall of the groove assembly and the adjustment ring 78 can be observed when adjusting the position of the mounting cylinder 734. When the gap is adjusted to the set range, the gap of the maze channel can be ensured to be adjusted to the optimal value. To ensure the dimensional accuracy of the convex tube 71, convex plate 72 and adjustment ring 78, the convex tube 71, convex plate 72 and adjustment ring 78 can be made of plastic and integrally molded by injection molding.

[0032] Since the concave ring 731 is composed of two separate parts with a gap, in order to prevent leakage, a sealing ring 739 is provided between the sealing ring 732 and the mounting cylinder 734, and between the mounting cylinder 734 and the inner wall of the bearing sleeve 6. The sealing ring 732 is close to the side wall of the concave ring 731. Axial leakage from the gap can only leak into the labyrinth channel. Since the gap is small, it can also be regarded as part of the labyrinth channel itself. Therefore, axial leakage does not affect the function of the labyrinth channel, while radial leakage from the gap is intercepted by the sealing ring 739 and will not leak to the outside.

[0033] Since the closing ring 732 itself is elastic, it is difficult to provide effective pressure to the sealing ring 739. Therefore, 2-3 closing rings 732 are combined into a whole and fitted onto the corresponding concave ring 731. The 2-3 rings forming a whole can not only form a groove and fit onto the concave ring 731, but also facilitate the stretching to expand the diameter. The concave ring 731 provides support for the closing ring 732 and ultimately provides a sufficiently large sealing pressure to the sealing ring 739.

[0034] Because particulate matter is present in the gas, although most of it flows back to the inlet 3 through the return pipe 10, a very small amount may still enter the labyrinth channel. Some particles of certain diameters may remain in the labyrinth channel for an extended period. When the convex disc 72 and the convex tube 71 rotate relative to each other, these particles may damage the labyrinth channel. Therefore, please refer to [further details needed]. Figure 6 The concave ring 731 is hollow and has several through holes on its inner wall. When particles flow with air through the concave ring 731, they will enter the interior of the concave ring 731 through the through holes, thus preventing them from damaging the labyrinth passage. At the same time, the inner cavity of the concave ring 731 can also serve as part of the expansion cavity, increasing the volume of the expansion cavity and enhancing the labyrinth passage effect. The concave ring 731 can be integrally molded from plastic.

[0035] During assembly, first, place the concave ring 731 onto the corresponding convex disc 72, with a gap of one convex disc 72 between two concave rings 731. Tighten the fastening bolts on each concave ring 731. Then, place the closing ring 732 between the two concave rings 731. Since the closing ring 732 can be elastically stretched, it can be easily put onto the concave ring 731 by pulling. After the concave rings 731 and the closing ring 732 are installed, insert the fastening rod 733 to tighten, completing the installation of the groove assembly. Then, insert the mounting sleeve 734 and screw in the clamping tube 736 to clamp the groove assembly. Measure the gap between the adjusting ring 78 and the groove assembly to see if the gap is appropriate. Disassemble and reassemble the mounting sleeve 734, and adjust the thickness of the adjusting shim 737 to complete the assembly of the labyrinth seal assembly 7. Next, place the sealing block 738 onto the convex tube 71, and insert the labyrinth seal assembly 7 into the bearing sleeve 6. Tighten the fastening bolts between the mounting disc 76 and the bearing sleeve 6. Finally, the closed cylinder 74 is fitted onto the impeller shaft 8, and its two ends are placed on the end of the convex tube 71 and the sealing flange 77 respectively. It is then clamped with a clamping plate. Finally, the impeller shaft 8 is connected to the output shaft of the motor 1.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A ventilation fan for public health prevention of occupational chemical gas poisoning, comprising a housing (2) and a motor (1), the housing (2) having an inlet (3) and an outlet (4), a bearing (5) being connected to one side of the housing (2) via a bearing sleeve (6), and an impeller shaft (8) being driven by the motor (1), the impeller shaft (8) passing through the bearing (5) and connected to an impeller, characterized in that: The bearing sleeve (6) is fixedly connected to the mounting plate (76), and the mounting plate (76) is movably connected to the convex tube (71) with several protrusions through the mounting bearing (75). The mounting plate (76) is fixedly connected to the concave tube (73) with grooves, and the grooves and protrusions correspond one-to-one and cooperate to form a maze passage. The end of the concave tube (73) is sealed by a sealing block (738) against the inner end face of the bearing sleeve (6). A sealing flange (77) is welded to the side wall of the impeller shaft (8). The end of the convex tube (71) is sealed and fastened to the sealing flange (77) by a flexible closed cylinder (74). The bearing (5) and the concave tube (73) form a reflux chamber. The reflux chamber (9) is connected to the suction port (3) through the reflux pipe (10).

2. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 1, is characterized in that... The protrusion is an annular convex disk (72), and the groove is an annular groove. The convex disk (72) and the annular groove form a radial labyrinth channel, and the top of the groove and the top of the concave disk form an expansion cavity.

3. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 2, is characterized in that... The concave tube (73) includes a concave ring (731), a closing ring (732), a fastening rod (733), and a mounting sleeve (734). The concave ring (731) is composed of two semicircular parts, which are fixed by fastening bolts. The closing ring (732) is located between two adjacent concave rings (731), and the two adjacent concave rings (731) are spaced apart by a convex plate (72). The fastening rod (733) passes through each concave ring (731) and the closing ring (732) to tighten them. The mounting cylinder (734) is fixed as a whole to form a groove assembly. The inner wall of the mounting cylinder (734) is provided with an inner edge (735). The inward end of the mounting cylinder (734) is threadedly connected to a clamping tube (736). The outer wall of the groove assembly is close to the inner wall of the mounting cylinder (734) and is located between the inner edge (735) and the clamping tube (736). The groove assembly is clamped by the inner edge (735) and the clamping tube (736). The mounting cylinder (734) is threadedly connected to the inner wall of the mounting plate (76).

4. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 3, is characterized in that... The closed ring (732) can be stretched radially but cannot be compressed axially.

5. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 4, is characterized in that... An adjustment pad (737) is provided between the mounting cylinder (734) and the mounting plate (76). An adjustment ring (78) is provided on the innermost side of the convex tube (71). When the gap between the adjustment ring (78) and the groove assembly reaches the set value, the gap of the labyrinth channel is the optimal value. The convex tube (71), the convex plate (72) and the adjustment ring (78) are made of plastic and are integrally formed by injection molding.

6. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 3, is characterized in that... A sealing ring (739) is provided between the closing ring (732) and the mounting cylinder (734) and between the mounting cylinder (734) and the inner wall of the bearing sleeve (6).

7. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 6, is characterized in that... Two or three of the closed rings (732) are arranged as a whole and fitted onto the corresponding concave ring (731).

8. The ventilation fan for preventing occupational chemical gas poisoning in public health, as described in claim 3, is characterized in that... The concave ring (731) is hollow and has several through holes on its inner wall.

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