Air filter for hydraulic tank of boarding bridge

Abstract

This utility model relates to an air filter for the hydraulic oil tank of a boarding bridge, comprising an air filter body made of transparent material, which is divided into a first section, a second section, and a third section from top to bottom. The first section and the second section are threaded together, and the second section and the third section are an integral structure. The upper part of the first section is filled with an upper filter screen, and a guide plate is fixedly connected to the lower part of the inner wall of the second section. The guide plate is spiral-shaped, and desiccant and a lower filter screen are filled from top to bottom above the guide plate. The desiccant is placed in a receiving cavity. The third section is a tubular structure, coaxially arranged with the second section. The third section is divided into an inner tube and an outer tube arranged coaxially. The inner tube and the outer tube form a double-layer flow channel. The outer flow channel is used for air to flow downward into the hydraulic oil tank, and the inner flow channel is used for the hydraulic oil tank to exhaust air outward.

Description

Technical Field

[0001] This utility model relates to the field of air filter technology, specifically to an air filter for a boarding bridge hydraulic oil tank. Background Technology

[0002] Airport boarding bridges are movable, lift-up passageways used in airports to connect waiting areas with aircraft. Currently, most airport terminals use boarding bridges for boarding and disembarking. As a key facility in modern airports, the safe and stable operation of boarding bridges is of paramount importance.

[0003] Existing airport boarding bridges typically use hydraulic cylinders for lifting and lowering. During this process, the hydraulic oil tank draws in or expels air as needed. Because air contains moisture, condensation forms as the temperature changes, mixing into the hydraulic oil. Long-term exposure to condensation accelerates hydraulic oil deterioration and emulsification. This is especially problematic in northern coastal areas where low winter temperatures cause condensation to freeze inside hydraulic valves, leading to valve jamming and malfunctions, affecting equipment safety. In summer, frequent rainfall increases air moisture content, resulting in a higher concentration of condensation in the hydraulic oil, severely impacting its quality.

[0004] While existing boarding bridges have air filtration systems above their hydraulic tanks, these typically only filter impurities from the air and cannot absorb moisture, thus failing to solve the condensation problem. Since the hydraulic tank operates outdoors with the boarding bridge, especially in humid coastal environments, pressure fluctuations within the tank allow moisture from the air to easily enter the hydraulic system during cylinder intake and exhaust, affecting the quality of the hydraulic oil. This, in turn, impacts the safety and stability of the boarding bridge's operation, significantly shortens the hydraulic oil replacement cycle, and increases maintenance costs. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the prior art and provide an air filter for the hydraulic oil tank of a boarding bridge. The filter is provided with a lower filter screen, a desiccant and an upper filter screen from bottom to top. The upper and lower filter screens have a dual filtration effect. The desiccant in the filter can effectively absorb moisture in the air, effectively preventing moisture in the air from entering the oil circuit and affecting the quality of the hydraulic oil, and extending the hydraulic oil replacement cycle.

[0006] An embodiment of this utility model provides an air filter for the hydraulic oil tank of a boarding bridge, including an air filter body. The air filter body is made of transparent material and is divided into a first section, a second section, and a third section from top to bottom. The first section and the second section are threaded together, and the second section and the third section are an integral structure. The upper part of the first section is filled with an upper filter screen. A guide plate is fixedly connected to the lower part of the inner wall of the second section. The guide plate is spiral-shaped. A desiccant and a lower filter screen are filled from top to bottom above the guide plate in the second section. The desiccant is placed in a receiving cavity. The third section is a tubular structure and is coaxially arranged with the second section. The third section is divided into an inner tube and an outer tube arranged coaxially. The inner tube and the outer tube form a double-layer flow channel. The outer flow channel is used for air to flow downward into the hydraulic oil tank, and the inner flow channel is used for the hydraulic oil tank to exhaust air outward.

[0007] Further configured, the first section has a one-way valve at the center of its upper part and an external thread at its lower part; the second section has an internal thread at its upper part, and the outer diameter of the second section is slightly larger than that of the first section, and the second section and the first section are connected as one unit by threads; the upper end of the third section extends into the upper part of the first section, and the lower end protrudes from the bottom surface of the second section, and the protruding part has an external thread for connecting a flange, and the flange is fixed at the vent on the top surface of the hydraulic oil tank.

[0008] Further configured, the lower end of the one-way valve is provided with a rubber sealing ring, and the upper end of the inner tube abuts against the annular groove reserved in the rubber sealing ring to form a complete exhaust channel; both ends of the inner tube are higher than the outer tube, and the lower end of the inner tube is connected to the inner wall of the outer tube through an annular one-way partition, which only allows air to flow from top to bottom.

[0009] Further configured, the receiving cavity is a cylindrical cavity, divided into a main body and a bent part formed by bending outward from the top opening; the second section has an annular platform on the inner wall below the internal thread, the outer diameter of the receiving cavity main body is slightly smaller than the inner diameter of the annular platform, so that the receiving cavity main body can pass through the annular platform and be placed inside the second section, and the annular platform provides support for the bent part of the receiving cavity.

[0010] Further, the cavity is made of a transparent material with a vent hole on the bottom surface, the vent hole diameter being smaller than the particle size of the desiccant; a hole is opened at the center of the bottom surface of the cavity, the diameter of which matches the outer diameter of the third section; fixing rings are also provided on both sides of the bent part of the cavity, and the cavity is inserted and removed through the fixing rings; the outer wall of the cavity is also wrapped with a layer of phase change material.

[0011] Further configured, the flange includes an upper boss and through holes. The upper boss is located on the upper surface of the center of the flange and has a hollow structure, with its inner diameter slightly larger than the outer diameter of the third section. The inner surface of the upper boss is threaded, forming a threaded connection with the external thread of the third section. The through holes are evenly distributed around the flange and correspond one-to-one with the connection holes reserved on the top surface of the hydraulic oil tank. Screws are installed in the through holes to fix the flange to the top surface of the hydraulic oil tank.

[0012] A further configuration is provided whereby an O-ring silicone gasket is provided on the connection surface between the air filter body and the flange, and the inner diameter of the O-ring silicone gasket is the same as the outer diameter of the upper boss.

[0013] Further configured, the upper filter and the lower filter are glass fiber filters; the center of both the upper filter and the lower filter has a channel through which the third section can pass, and the upper surface of the upper filter is lower than the upper port of the outer tube of the third section.

[0014] Further configured, the desiccant is calcium chloride desiccant.

[0015] Further configured, the transparent material is a styrene-acrylonitrile transparent thermoplastic resin.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. This utility model directly installs the air filter at the vent above the boarding bridge's hydraulic tank, without affecting the boarding bridge's electrical or hydraulic circuits. Air enters the filter through the inlet below, passing sequentially through the lower filter screen, desiccant, and upper filter screen. The two filter layers provide a dual filtration effect, and the desiccant absorbs moisture from the air, effectively preventing moisture from entering the hydraulic circuit and affecting the quality of the hydraulic oil, thus extending the hydraulic oil replacement cycle. It is especially suitable for boarding bridge hydraulic tanks used outdoors in humid seasons or coastal areas, significantly extending the service life of the boarding bridge's hydraulic system and saving labor costs, equipment costs for hydraulic oil changes, and hydraulic oil costs.

[0018] 2. This utility model ensures that during the venting process of the hydraulic oil tank, the internal air will not flow backward through the desiccant, thus avoiding the problem of desiccant saturation acceleration caused by backflow of exhaust.

[0019] 3. This utility model can monitor the status of the desiccant in real time, and the desiccant can be removed and replaced. Moreover, the desiccant can be reused. The outer wall of the receiving cavity is wrapped with a layer of phase change material, which can maintain the relative stability of the desiccant's working temperature, extend the desiccant replacement cycle, and further reduce the cost of use. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0021] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the air filter body structure of Embodiment 1 of this utility model;

[0023] Figure 3 This is a top view of the flange structure of Embodiment 1 of this utility model;

[0024] Figure 4 This is a cross-sectional view of the flange structure of Embodiment 1 of this utility model;

[0025] In the diagram: 1. Air filter body; 2. First section; 3. Second section; 4. Third section; 5. Upper filter screen; 6. Desiccant; 7. Lower filter screen; 8. Flange; 9. Upper boss; 10. Through hole; 11. Hydraulic oil tank; 12. Screw; 13. O-ring; 14. Vent; 15. Air inlet; 16. Receiving cavity; 17. Annular platform; 18. Fixing ring; 19. Inner tube; 20. Outer tube; 21. One-way baffle; 22. One-way valve; 23. Guide plate. Detailed Implementation

[0026] Example 1

[0027] This embodiment provides an air filter for the hydraulic oil tank of a boarding bridge, such as... Figure 1 As shown, the present invention directly fixes the air filter body 1 to the vent 14 above the hydraulic oil tank 11 through the flange 8. The filtered and dried air enters the hydraulic oil tank 11 through the vent 14 without changing the original circuit and oil circuit.

[0028] Specifically, such as Figure 2 As shown, the air filter body 1 is made of transparent material and is cylindrical in shape. From top to bottom, it is divided into a first section 2, a second section 3 and a third section 4. The first section 2 and the second section 3 are threaded together, and the second section 3 and the third section 4 are an integral structure.

[0029] The upper part of the first section 1 is filled with an upper filter screen 5. The lower part of the first section 2 is provided with external threads, and the upper part of the second section 3 is provided with internal threads. The outer diameter of the second section 3 is slightly larger than that of the first section 2. The second section 3 and the first section 2 are connected as one unit by threads.

[0030] In this embodiment, as Figure 2As shown, the bottom of the second section 3 has multiple air inlets 15 arranged circumferentially. When the hydraulic oil tank 11 draws in air, outside air enters the air filter body 1 through the air inlets 15 at the bottom of the second section 3. A guide plate 23 is fixedly connected to the lower part of the inner wall of the second section 3. The guide plate 23 is spiral-shaped. After the outside air enters through the air inlets 15 at the bottom of the second section 3, the guide plate 23 can split the air, increase the airflow path, and make the air pass through the lower filter screen 7 more evenly, thereby improving the filtration effect. At the same time, the air flowing through the spiral guide plate 23 can form a vortex to a certain extent, using centrifugal force to separate liquid water droplets and large dust particles in the air, reducing the load on the lower filter screen 7. The upper part of the guide plate in the second section 3 is filled with desiccant 6 and the lower filter screen 7 from top to bottom. The desiccant 6 is placed in the receiving cavity 16. The receiving cavity 16 is a cylindrical cavity, divided into a main body and a bent part formed by bending outward from the top opening. The second section 3 has an annular platform 17 on the inner wall below the internal thread. The outer diameter of the main body of the receiving cavity 16 is slightly smaller than the inner diameter of the annular platform 17, ensuring that the main body of the receiving cavity 16 can pass through the annular platform 17 and be placed inside the second section 3. At the same time, the annular platform 17 provides support for the bent part of the receiving cavity 16.

[0031] The third section 4 is a tubular structure, coaxially arranged with the second section 3. The third section consists of an inner tube 19 and an outer tube 20, coaxially arranged. The inner tube 19 and outer tube 20 form a double-layer flow channel. The outer flow channel allows air to flow downwards into the hydraulic oil tank 11, while the inner flow channel allows the hydraulic oil tank 11 to exhaust air outwards. Both ends of the inner tube 19 are higher than the outer tube 20, creating a height misalignment. The lower end of the inner tube 19 is connected to the inner wall of the outer tube 20 via an annular one-way baffle 21. The one-way baffle 21 only allows air to flow downwards. When the hydraulic oil tank 11 exhausts air, air inevitably flows backwards through the desiccant 6 from the outer flow channel. The one-way baffle prevents the backflow of exhaust air from causing the desiccant 6 to saturate and accelerate. The one-way baffle 21 can be made of a one-way breathable polymer material with a microporous structure, such as a composite one-way breathable sheet made of polyethylene polymer breathable membrane combined with other materials.

[0032] After the first section 2 is connected to the second section 3, the upper end of the third section 4 extends into the upper part of the first section 2. A one-way valve 22 is located at the center of the upper part of the first section 2, and air can only be discharged outward through the one-way valve 22. A rubber sealing ring is provided at the lower end of the one-way valve 22, and the upper end of the inner tube 19 abuts against the annular groove reserved in the rubber sealing ring, forming a complete exhaust channel.

[0033] The lower end of the outer tube 20 protrudes from the bottom surface of the second section 3. The protruding part is provided with external threads for connecting the flange 8. The flange 8 is fixed at the vent 14 on the top surface of the hydraulic oil tank 11.

[0034] The lower end of the outer pipe 20 of the third section 4 is connected to the vent 14 of the hydraulic oil tank 11, forming a complete air flow path. A certain gap is left between the upper end of the outer pipe 20 of the third section and the inner wall of the first section 2, so that the filtered air can enter the outer flow channel of the third section 4 through the gap.

[0035] In this embodiment, the upper filter 5 and the lower filter 7 both have channels in the center that allow the third section 4 to pass through. After filling, the upper surface of the upper filter 5 in the first section 2 is lower than the upper port of the third section 4, ensuring that the impurities filtered in the upper filter 5 will not enter the airflow channel.

[0036] An opening is made at the center of the bottom surface of the receiving cavity 16, and the diameter of the opening matches the outer diameter of the third section. Fixing rings 18 are also provided on both sides of the bent part of the receiving cavity 16 to facilitate the insertion and removal of the receiving cavity 16. After the receiving cavity 16 is removed, the desiccant 6 inside can be replaced.

[0037] In this embodiment, the cavity 16 is made of transparent plastic and has a vent hole on the bottom. The vent hole has a smaller diameter than the particle size of the desiccant 6, which ensures that it does not affect the passage of air while preventing the desiccant 6 from leaking out of the vent hole.

[0038] The outer wall of the receiving cavity 16 is also covered with a layer of phase change material to maintain the relative stability of the desiccant 6's operating temperature and extend the desiccant's replacement cycle. Under high-temperature conditions, the phase change material layer absorbs heat and melts, which can prevent the desiccant from overheating and failing; under low-temperature conditions, the phase change material layer solidifies and releases heat, maintaining the desiccant's active temperature and avoiding the problem of the desiccant freezing and failing under the cold conditions of northern winters.

[0039] In this embodiment, the upper filter 5 and the lower filter 7 are made of glass fiber filter screens with high filtration efficiency, low resistance, good heat resistance and chemical resistance.

[0040] Desiccant 6 uses highly efficient adsorption materials, such as calcium chloride desiccant. Calcium chloride desiccant works by chemically reacting water molecules with calcium chloride, absorbing moisture from the surrounding environment and transforming it into a gel, thus achieving adsorption. Common silica gel desiccants can only absorb 10%-27% of their own weight, while calcium chloride desiccant can reach 300%, making its moisture absorption rate 8-15 times that of ordinary desiccants.

[0041] Since calcium chloride desiccant can combine water vapor with calcium chloride to form a gel, its condition can be observed to determine whether it needs to be replaced. To replace the desiccant, simply use a hairdryer to heat it and soften the adhesive on the screws, then unscrew section 2 from section 3 to remove the desiccant. Furthermore, calcium chloride desiccant can be dried and reused after absorbing moisture, helping to reduce operating costs.

[0042] In this embodiment, the air filter body 1 is entirely made of transparent material, which, together with the transparent receiving cavity 16, facilitates observation of the desiccant's condition and determines whether it needs to be replaced. Specifically, the air filter body 1 can be made of a material with high transparency and strength, such as styrene-acrylonitrile (SAN) transparent thermoplastic resin. This material has excellent gloss, high temperature resistance, and chemical resistance, as well as good hardness and dimensional stability, making it suitable for various application environments.

[0043] In this embodiment, as Figure 3 and Figure 4 As shown, the flange 8 includes an upper boss 9 and a through hole 10. The upper boss 9 is located on the upper surface of the center of the flange 8. The upper boss 9 is a hollow structure, and its inner diameter is slightly larger than the outer diameter of the third section 4. The inner surface of the upper boss 9 is provided with threads, which form a threaded connection with the external threads of the third section 4. The through holes 10 are evenly distributed around the flange and correspond one-to-one with the connection holes reserved on the top surface of the hydraulic oil tank 11. Screws 12 are installed in the through holes 10 to fix the flange 8 to the top surface of the hydraulic oil tank 11.

[0044] In this embodiment, before the third section 4 is threadedly connected to the flange 8, a dot of thread-locking adhesive can be applied to the middle section of the external thread of the third section 4. Then, the third section 4 is threadedly connected to the flange 8 and tightened. The thread-locking adhesive will not solidify in the air; it will only solidify after the threads are tightened and air is isolated, forming a sticky adhesive film between the threads. The thread-locking adhesive improves the airtightness of the threaded connection, preventing unfiltered external air from entering the hydraulic oil tank from the connection between the third section 4 and the flange 8.

[0045] like Figure 1 As shown, the connection surface between the air filter body 1 and the flange 8 is provided with an O-ring rubber gasket 13. The inner diameter of the O-ring rubber gasket 13 matches the outer diameter of the upper boss 9. After the air filter body 1 and the flange 8 are threaded together, the O-ring rubber gasket 13 is pressed to further ensure the sealing effect at the connection.

[0046] The working principle of this utility model is as follows:

[0047] The lifting and lowering movement of the boarding bridge is powered by hydraulic cylinders. This process involves the inflow and outflow of hydraulic oil within the cylinders. A hydraulic oil tank stores and supplies hydraulic oil to the cylinders. Therefore, when the hydraulic system is operating, the oil level in the tank rises or falls as hydraulic oil flows in and out of the cylinders. When the oil level rises, positive pressure is created in the tank, requiring air to be expelled from the inside out. When the oil level falls, negative pressure is created, requiring air to be drawn in from the outside in.

[0048] When the hydraulic oil tank 11 draws in air, outside air enters the air filter body 1 through the air inlet 15 at the bottom of the second section 3. The air flows from bottom to top, passing through the lower filter screen 7, the desiccant 6, and the upper filter screen 5 in sequence. The upper and lower filter screens provide a double filtration effect, and the desiccant 6 absorbs the moisture in the air. The filtered and dried air enters the third section 4 from the top of the first section 2, flows through the outer air passage of the third section 4 and the air vent 14 of the hydraulic oil tank 11, and finally enters the hydraulic oil tank 11.

[0049] When air is discharged from the hydraulic oil tank 11, the internal air flows upward. It is blocked by the one-way baffle 21 and cannot enter the outer air flow channel of the third section 4. Instead, it can only enter the inner air flow channel and flow out of the air filter through the one-way valve of the first section 2.

[0050] This invention directly fixes the air filter body 1 to the vent 14 above the hydraulic oil tank 11 via the flange 8. Filtered and dried air enters the hydraulic oil tank 11 through the vent 14, without affecting the boarding bridge's electrical or hydraulic circuits. During the intake process of the hydraulic oil tank 11, the air undergoes double filtration, and the desiccant 6 absorbs moisture from the air, effectively preventing moisture from entering the oil circuit and affecting the quality of the hydraulic oil, thus extending the hydraulic oil replacement cycle. In humid seasons or regions, it can significantly extend the service life of hydraulic system components, saving labor costs, equipment costs for hydraulic oil changes, and hydraulic oil costs. During the exhaust process of the hydraulic oil tank 11, the internal air does not flow backward through the desiccant 6, avoiding the problem of accelerated saturation of the desiccant 6 due to backflow during exhaust.

[0051] Furthermore, the status of the desiccant 6 can be monitored in real time, and the container 16 containing the desiccant can be removed to replace the desiccant 6. Moreover, the desiccant 6 can be reused. The outer wall of the container 16 is covered with a layer of phase change material, which can maintain the relative stability of the working temperature of the desiccant 6, extend the replacement cycle of the desiccant 6, and further reduce the cost of use.

[0052] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. An air filter for the hydraulic oil tank of a boarding bridge, characterized in that, The system includes an air filter body, which is made of transparent material and is divided into a first section, a second section, and a third section from top to bottom. The first section and the second section are threaded together, and the second section and the third section are an integral structure. The upper part of the first section is filled with an upper filter screen, and a guide plate is fixedly connected to the lower part of the inner wall of the second section. The guide plate is spiral-shaped, and desiccant and a lower filter screen are filled from top to bottom above the guide plate in the second section. The desiccant is placed in a receiving cavity. The third section is a tubular structure, coaxially arranged with the second section. The third section is divided into an inner tube and an outer tube arranged coaxially. The inner tube and the outer tube form a double-layer flow channel. The outer flow channel is used for air to flow downward into the hydraulic oil tank, and the inner flow channel is used for the hydraulic oil tank to exhaust air outward.

2. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 1, characterized in that, The first section has a one-way valve at the center of its upper part and an external thread at its lower part; the second section has an internal thread at its upper part and its outer diameter is larger than that of the first section. The second section and the first section are connected as one unit by threads; the upper end of the third section extends into the upper part of the first section and the lower end protrudes from the bottom surface of the second section. The protruding part has an external thread for connecting a flange. The flange is fixed at the vent on the top surface of the hydraulic oil tank.

3. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 2, characterized in that, The lower end of the one-way valve is provided with a rubber sealing ring, and the upper end of the inner tube abuts against the annular groove reserved in the rubber sealing ring to form a complete exhaust channel; both ends of the inner tube are higher than the outer tube, and the lower end of the inner tube is connected to the inner wall of the outer tube through an annular one-way partition. The one-way partition only allows air to flow from top to bottom.

4. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 1, characterized in that, The receiving cavity is a cylindrical cavity, divided into a main body and a bent part formed by bending outward from the top opening; the second section has an annular platform on the inner wall below the internal thread, and the outer diameter of the receiving cavity main body is smaller than the inner diameter of the annular platform, so that the receiving cavity main body can pass through the annular platform and be placed inside the second section, and the annular platform provides support for the bent part of the receiving cavity.

5. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 4, characterized in that, The cavity is made of transparent material and has vent holes on its bottom surface. The vent holes have a diameter smaller than the particle size of the desiccant. The cavity has a hole at the center of its bottom surface, and the hole diameter matches the outer diameter of the third section. The cavity is also equipped with fixing rings on both sides of the bent part, which allow the cavity to be inserted and removed. The outer wall of the cavity is also covered with a layer of phase change material.

6. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 2, characterized in that, The flange includes an upper boss and through holes. The upper boss is located on the upper surface of the center of the flange and has a hollow structure with an inner diameter larger than the outer diameter of the third section. The inner surface of the upper boss is threaded, forming a threaded connection with the external thread of the third section. The through holes are evenly distributed around the flange and correspond one-to-one with the connection holes reserved on the top surface of the hydraulic oil tank. Screws are installed in the through holes to fix the flange to the top surface of the hydraulic oil tank.

7. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 2, characterized in that, The air filter body and the flange are connected by an O-ring silicone gasket, and the inner diameter of the O-ring silicone gasket is the same as the outer diameter of the upper boss.

8. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 1, characterized in that, The upper and lower filter screens are glass fiber filter screens; both the upper and lower filter screens have channels in the center for the third section to pass through, and the upper surface of the upper filter screen is lower than the upper port of the outer tube of the third section.

9. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 1, characterized in that, The desiccant is calcium chloride desiccant.

10. The air filter for the hydraulic oil tank of a boarding bridge as described in claim 1, characterized in that, The transparent material is styrene-acrylonitrile transparent thermoplastic resin.

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