Hydraulic oil filtering device

Abstract

The utility model provides a hydraulic oil filtering device which is used for filtering impurities in hydraulic oil of a hydraulic system, the hydraulic oil filtering device comprises a shell and a filtering assembly, a containing cavity is formed in the shell, the filtering assembly is located in the containing cavity, and the filtering assembly comprises a first filtering net, a second filtering net, a third filtering net and a separating membrane. The shell is provided with an oil inlet, an oil outlet and a water outlet, the oil inlet is used for allowing hydraulic oil to enter, the first filter screen, the second filter screen, the third filter screen and the separation membrane are sequentially arranged in the direction away from the oil inlet and filter the hydraulic oil step by step, and the first filter screen is used for filtering coarse impurities in the hydraulic oil; the second filter screen is used for filtering and adsorbing metal particles in the hydraulic oil, the third filter screen is used for filtering fine impurities in the hydraulic oil, the separation membrane is used for filtering and separating moisture in the hydraulic oil, the oil outlet is used for discharging the filtered and separated hydraulic oil, and the water outlet is used for discharging the separated moisture.

Description

Technical Field

[0001] This utility model relates to the technical principles of hydraulic equipment, and in particular to a hydraulic oil filtration device. Background Technology

[0002] Hydraulic oil is the lifeblood of hydraulic machinery, serving functions such as cooling, metal-to-metal isolation, and anti-wear and anti-oxidation. It not only affects the working performance of the hydraulic system but also the service life of the system and its components. Surveys indicate that 70% of hydraulic system failures are caused by hydraulic oil contamination. Therefore, ensuring the normal operation of a hydraulic system is paramount in preventing hydraulic oil contamination. The recycling and reuse of contaminated hydraulic oil has gained significant attention in my country.

[0003] An existing hydraulic oil filtration and recovery device includes a body, a screen filter, a magnetic filter, a centrifugal filter, a component analyzer, and an additive addition device. The upper end of the body is connected to the lower ends of the screen filter, the magnetic filter, and the centrifugal filter. The end of the screen filter is connected to the front of the centrifugal filter, and the end of the centrifugal filter is connected to the front of the component analyzer. The screen filter removes small particulate impurities from the waste hydraulic oil, the magnetic filter removes small metal particles, and the centrifugal filter removes water. However, this filtration and recovery device uses many filters, which are expensive, and the operating cost is high when processing lightly contaminated oil. Furthermore, the centrifugal filter used for oil-water separation is not thorough enough, and the centrifugal filter itself is also relatively expensive. Utility Model Content

[0004] The purpose of this invention is to provide a hydraulic oil filtration device to solve the problems of high price, high operating cost, and incomplete filtration separation of existing filtration devices.

[0005] This utility model provides a hydraulic oil filtration device for filtering impurities in hydraulic oil of a hydraulic system. The hydraulic oil filtration device includes a housing and a filter assembly. The housing has a receiving cavity, and the filter assembly is located in the receiving cavity. The filter assembly includes a first filter screen, a second filter screen, a third filter screen, and a separation membrane. The housing has an oil inlet, an oil outlet, and a water outlet. The oil inlet is used to allow the hydraulic oil to enter. The first filter screen is positioned opposite the oil inlet. The first filter screen, the second filter screen, the third filter screen, and the separation membrane are arranged sequentially away from the oil inlet, filtering the hydraulic oil stage by stage. The first filter screen is used to filter coarse impurities in the hydraulic oil. The second filter screen is used to filter and adsorb metal particles in the hydraulic oil. The third filter screen is used to filter fine impurities in the hydraulic oil. The separation membrane is used to filter and separate water from the hydraulic oil. The oil outlet is used to discharge the filtered and separated hydraulic oil, and the water outlet is used to discharge the separated water.

[0006] In one embodiment of this utility model, the first filter screen is a stainless steel filter screen, the second filter screen is a magnetic filter screen composed of a combination of magnetic material and a barrier filter screen, and the third filter screen is a copper mesh.

[0007] In one embodiment of this utility model, the separation membrane includes a hydrophilic separation membrane and an oleophilic separation membrane. The hydrophilic separation membrane allows water to pass through, and the oleophilic separation membrane allows hydraulic oil to pass through. The hydrophilic separation membrane is disposed corresponding to the water outlet and is connected to the water outlet, and the oleophilic separation membrane is disposed corresponding to the oil outlet and is connected to the oil outlet.

[0008] In one embodiment of this utility model, a semi-circular partition is further provided in the accommodating cavity. The semi-circular partition is located below the third filter screen. The hydrophilic separation membrane and the oleophilic separation membrane are both inclined towards the semi-circular partition in the accommodating cavity and are both connected to the semi-circular partition. The hydrophilic separation membrane and the oleophilic separation membrane intersect to form an included angle, which is 30°~90°.

[0009] In one embodiment of the present invention, the housing includes an upper cover, a cylindrical portion, and a lower cover. The upper cover is disposed at one end of the cylindrical portion, and the lower cover is disposed at the other end of the cylindrical portion. Both the upper cover and the lower cover are sealed to the cylindrical portion to enclose and form the accommodating cavity. The upper cover has an oil inlet. The cross-sectional area of ​​the cylindrical portion decreases from the upper cover toward the semi-circular partition and increases from the semi-circular partition toward the lower cover.

[0010] In one embodiment of the present invention, the hydraulic oil filtration device further includes a heating device, which is located in the accommodating cavity and fixedly installed on the upper cover. The heating device is used to heat the hydraulic oil to keep the hydraulic oil at a preset temperature.

[0011] In one embodiment of this utility model, the hydraulic oil filtration device further includes a pressure gauge and a differential pressure transmitter. The pressure gauge is located in the accommodating cavity and fixedly connected to the cylindrical part. The pressure gauge is used to monitor the working pressure and the degree of contamination of the filter components. The differential pressure transmitter is fixedly installed in the cylindrical part and is used to monitor the replacement time of the first filter screen, the second filter screen and the third filter screen.

[0012] In one embodiment of this utility model, the hydraulic oil filtering device further includes a cylinder and a trolley. The housing is installed inside the cylinder, the cylinder is installed on the trolley, and the trolley can be moved to a designated position.

[0013] In one embodiment of this utility model, the hydraulic oil filtering device further includes an air filter, which is fixedly installed on the upper cover and is used to discharge air.

[0014] In one embodiment of the present invention, the hydraulic oil filtering device further includes a power component, which provides power to allow the hydraulic oil to enter from the inlet and exit from the outlet.

[0015] In the hydraulic oil filtration device of this utility model, impurities in the hydraulic oil are filtered layer by layer through the first filter screen, the second filter screen and the third filter screen in the filtration assembly. This can effectively filter the hydraulic oil and is inexpensive, reducing the cost of use. At the same time, a separation membrane is also set up to separate oil and water, which is thorough and has low operating costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the internal structure of a hydraulic oil filtration device according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the overall structure of a hydraulic oil filtration device according to an embodiment of the present invention. Detailed Implementation

[0018] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0019] This utility model provides a hydraulic oil filtration device for filtering impurities in the hydraulic oil of a hydraulic system. For example... Figure 1-2As shown, the hydraulic oil filtration device of this embodiment includes a housing 11, a filter assembly 12 and a power assembly 13. The housing 11 has a receiving cavity 111, and the filter assembly 12 is located in the receiving cavity 111 and is fixedly connected to the housing 11. The filter assembly 12 includes a first filter screen 121, a second filter screen 122, a third filter screen 123, and a separation membrane 124. The housing 11 has an oil inlet 112, an oil outlet 113, and a water outlet 114. The oil inlet 112 is used to supply hydraulic oil. The first filter screen 121 is positioned directly opposite the oil inlet 112. The first filter screen 121, the second filter screen 122, the third filter screen 123, and the separation membrane 124 are arranged sequentially in a direction away from the oil inlet 112, and the hydraulic oil is filtered step by step. Specifically, the housing 11 includes an upper cover 115, a cylindrical portion 116, and a lower cover 117. The cylindrical portion 116 may be a hollow cylindrical structure. The first filter screen 121, the second filter screen 122, and the third filter screen 123 are arranged parallel to each other and are all perpendicular to the central axis of the cylindrical portion 116. The first filter screen 121 is used to filter coarse impurities in the hydraulic oil, the second filter screen 122 is used to filter and adsorb metal particles in the hydraulic oil, the third filter screen 123 is used to filter fine impurities in the hydraulic oil, the separation membrane 124 is used to filter and separate water in the hydraulic oil, the oil outlet 113 is used to discharge the filtered and separated hydraulic oil, the water outlet 114 is used to discharge the separated water, and the power unit 13 is used to provide power to make the hydraulic oil enter from the oil inlet 112 and exit from the oil outlet 113.

[0020] In the hydraulic oil filtration device of this invention, impurities in the hydraulic oil are filtered layer by layer through the first filter screen 121, the second filter screen 122, and the third filter screen 123 in the filter assembly 12. This effectively filters the hydraulic oil at a low cost, reducing operating costs. Simultaneously, a separation membrane 124 is also provided for oil-water separation, ensuring thorough separation and low operating costs. The hydraulic oil filtration device is small in size, inexpensive, and easy to move.

[0021] The hydraulic oil filtration device in this embodiment is a purely physical filtration (non-chemical) system, primarily targeting lightly contaminated oils, focusing on removing mechanical impurities, trace amounts of moisture, and colloidal particles. Existing filtration devices generally use filters to separate impurities; however, filters are expensive, inconvenient to replace, and their filter elements are typically made of fiberglass, filter paper, or metal mesh, resulting in a short lifespan. This embodiment's hydraulic oil filtration device does not use filters but instead employs a three-stage filtration system: coarse filtration + magnetic filtration + fine filtration (first filter 121 + second filter 122 + third filter 123) to remove particulate matter, achieving a maximum oil purification effect of NAS6.

[0022] Specifically, the first filter screen 121 is made of stainless steel, filtering out most coarse impurities such as rust, paint, large dust particles, and welding slag. Stainless steel filters are strong, have low resistance, can be repeatedly washed, are economical, safe, robust, have a long service life, are reliable, have low operating costs, and their lightweight plate structure makes replacement easy and safe, allowing for user-friendly operation. The second filter screen 122 is a magnetic filter, primarily used to filter and adsorb metal particles. The magnetic filter screen is composed of magnetic materials and a barrier filter. The third filter screen 123 is made of copper mesh, primarily used to filter fine impurities. In addition to its strong corrosion resistance, the copper mesh reduces the impact of liquids on the entire filter screen, providing some protection for the equipment. Furthermore, copper is an alloy wire product with a long service life and can be used to screen various particulate dust, clay, glass, porcelain printing, and filter liquids and gases. The third filter 123 can be freely selected from 3μm, 5μm, 10μm, 20μm and 30μm according to different needs. Different filtration effects can be achieved by simply changing the filter with different filtration precision.

[0023] In this embodiment, the separation membrane 124 is an oil-water separation membrane, comprising a hydrophilic separation membrane 1241 and an oleophilic separation membrane 1242. The hydrophilic separation membrane 1241 allows water to pass through but not oil; the oleophilic separation membrane 1242 allows hydraulic oil to pass through but not water. The hydrophilic separation membrane 1241 is positioned corresponding to and connected to the water outlet 114, and the oleophilic separation membrane 1242 is positioned corresponding to and connected to the oil outlet 113. The separation membrane 124 separates the hydraulic oil from the water; the hydraulic oil flows out from the oil outlet 113, and the water is discharged from the water outlet 114. Both the oil outlet 113 and the water outlet 114 are located on the cylindrical portion 116, with the height of the water outlet 114 lower than the height of the oil outlet 113.

[0024] Specifically, a semi-circular partition 125 is also provided inside the receiving cavity 111. The semi-circular partition 125 is located below the third filter screen 123. The hydrophilic separation membrane 1241 and the oleophilic separation membrane 1242 are both inclined towards the semi-circular partition 125 inside the receiving cavity 111 and are both connected to the semi-circular partition 125. The hydrophilic separation membrane 1241 and the oleophilic separation membrane 1242 intersect to form an included angle, which is 30° to 90°. Those skilled in the art can set the included angle to 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, etc., according to the actual situation, and no unique limitation is made here. The hydrophilic separation membrane 1241 and the oleophilic separation membrane 1242 are located below the third filter screen 123. Their cross-sectional areas in the vertical plane can be considered a triangle, and they are connected in a triangular structure. A high-polymer composite emulsified oil-water separation membrane material is used for oil-water separation. A semi-circular partition 125, the oleophilic separation membrane 1242, and the cylindrical portion 116 enclose a first cavity (not labeled) for hydraulic oil flow. This first cavity is connected to the oil outlet 113. The hydraulic oil separated by the oleophilic separation membrane 1242 enters the first cavity and then flows out from the oil outlet 113. A second cavity (not labeled) is enclosed by the semi-circular partition 125, the hydrophilic separation membrane 1241, the cylindrical portion 116, and the lower cover 117. This second cavity is connected to the water outlet 114. The water separated by the hydrophilic separation membrane 1241 enters the second cavity and then flows out from the water outlet 114.

[0025] Using the hydraulic oil filtration device of this embodiment, normally contaminated hydraulic oil no longer needs to be removed by centrifugal filtration device or vacuum dehydrator. Instead, oil and water are separated by using a polymer composite emulsified oil-water separation membrane material, which can effectively reduce operation steps, reduce labor costs and hazardous waste treatment costs.

[0026] In this embodiment, the upper cover 115 is located at one end of the cylindrical portion 116, and the lower cover 117 is located at the other end of the cylindrical portion 116. Both the upper cover 115 and the lower cover 117 are sealed to the cylindrical portion 116 to form a receiving cavity 111. The upper cover 115 has an oil inlet 112. The cross-sectional area of ​​the cylindrical portion 116 decreases from the upper cover 115 toward the semi-circular partition 125 and increases from the semi-circular partition 125 toward the lower cover 117, presenting an overall conical structure. The housing 11 adopts a conical quick-opening structure, which allows the upper cover 115 to be opened quickly and easily to replace the various filters. One of the core features of the conical quick-opening structure is its unique conical sealing surface. This design utilizes the self-aligning characteristics of the conical surface, enabling automatic alignment and uniform compression of the sealing gasket or ring when closed, thereby achieving a good sealing effect. At the same time, due to the angle design of the conical surface, only a minimum initial friction force needs to be overcome when opening, so the upper cover 115 can be opened quickly.

[0027] In this embodiment, the hydraulic oil filtration device also includes a heating device 14, which is located within the accommodating cavity 111 and fixedly installed on the upper cover 115. The heating device 14 is used to heat the hydraulic oil to maintain it at a preset temperature, such as 50°C. The hydraulic oil filtration device in this embodiment also employs a temperature sensor to monitor the hydraulic oil temperature in real time. In low-temperature environments, when the temperature sensor detects that the oil temperature is below normal, the heating device 14 is activated to heat the hydraulic oil, maintaining the oil temperature at 50°C. Through the auxiliary heating of the heating device 14, the cohesive force between molecules within the hydraulic oil decreases, and the oil viscosity decreases accordingly. At this temperature, the oil viscosity is suitable, allowing the power component 13 (specifically the hydraulic pump) to operate normally, ensuring smooth oil suction and better filtration. If the temperature sensor detects that the oil temperature is above 50°C, it transmits a signal to the electrical control program to shut off the heating device 14. The heating device 14 can maintain the oil viscosity at a normal level under low-temperature conditions, ensuring normal operation of the entire machine.

[0028] In this embodiment, the hydraulic oil filtration device also includes an air filter 21, which is fixedly installed on the upper cover 115. A large-capacity air filter 21 is selected so that the heated air in the accommodating cavity 111 can be discharged quickly and will not condense into water droplets on the cold upper cover 115 and fall into the accommodating cavity 111.

[0029] In this embodiment, the hydraulic oil filtration device further includes a pressure gauge 15 and a differential pressure transmitter 16. The pressure gauge 15 is located inside the accommodating cavity 111 and is fixedly connected to the cylindrical portion 116. The pressure gauge 15 is used to continuously indicate the operating status of the system and the degree of contamination of the filter assembly 12 during operation. The differential pressure transmitter 16 is fixedly installed in the cylindrical portion 116 and is used to monitor the replacement timing of the first filter screen 121, the second filter screen 122, and the third filter screen 123. When there is a red indicator, it indicates that the filter screen in the filter assembly 12 needs to be replaced.

[0030] In this embodiment, the hydraulic oil filtering device also includes a cylinder 17, and the housing 11 is installed inside the cylinder 17. In this embodiment, the hydraulic oil filtering device also includes a trolley 18, and the cylinder 17 is installed on the trolley 18. The trolley 18 can be moved to a designated position, which facilitates the overall movement of the hydraulic oil filtering device.

[0031] This utility model's hydraulic oil filtration device improves the filtration mode of hydraulic oil in the overall hydraulic system, allowing for hydraulic oil regeneration. It helps users better handle contaminants in the hydraulic system, extending the service life of hydraulic components, thereby reducing operating costs and improving overall machine efficiency. Existing filtration devices are relatively large, expensive, and fixed, making them inconvenient for filtering equipment located at long distances. The hydraulic oil filtration device of this embodiment is small, compact, and aesthetically pleasing. It can be moved easily, is convenient to maintain and use, and also boasts high precision and low noise. It can be used not only as a dedicated device for filtering new hydraulic oil but also as a dedicated device for periodically filtering contaminants from the system medium.

[0032] The power component 13 in the hydraulic oil filtration device of this embodiment includes two hydraulic pumps. Figure 2 Only one hydraulic pump is visible in the middle. Specifically, the hydraulic pump can be a special gear pump driven by an electric motor, which has the characteristics of low noise, strong self-priming ability and smooth operation.

[0033] The working principle of the hydraulic oil filtration device in this embodiment is as follows: One of the hydraulic pumps starts working and draws hydraulic oil from the oil tank (not shown) into the hydraulic oil filtration device through the oil inlet 112. The hydraulic oil enters the receiving cavity 111 through the oil inlet ball valve. The temperature sensor detects whether the temperature of the hydraulic oil entering the receiving cavity 111 is within the normal range. When the temperature sensor detects that the oil temperature is lower than the normal range, the heating device 14 is turned on to heat the hydraulic oil and maintain the oil temperature at 50°C. If the temperature sensor detects that the oil temperature is higher than 50°C, it sends a signal to the electrical control program to turn off the heating device 14. Air filter 21 quickly expels the heated air from the accommodating cavity 111, preventing it from condensing into water droplets on the cold top cover 115 and falling into the accommodating cavity 111. Subsequently, the hydraulic oil passes through the first filter screen 121, the second filter screen 122, and the third filter screen 123 in sequence to filter impurities in the hydraulic oil. Then, it passes through the separation membrane 124 to separate the water from the hydraulic oil. The separated water is discharged from the outlet 114, while the filtered and separated hydraulic oil is discharged from the outlet 113 through the oil ball valve and finally pumped back to the oil tank by another hydraulic pump. Through this continuous filtration for a period of time, the impurities in the hydraulic oil are thoroughly filtered out.

[0034] In this document, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of these terms based on the specific circumstances.

[0035] In this document, the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", "vertical", and "horizontal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the purpose of clarifying the technical solution and for the convenience of description, and therefore should not be construed as limiting the present utility model.

[0036] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0037] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A hydraulic oil filtration device for filtering impurities in hydraulic oil of a hydraulic system, characterized in that, The hydraulic oil filtration device includes a housing (11) and a filter assembly (12). The housing (11) has a receiving cavity (111), and the filter assembly (12) is located in the receiving cavity (111). The filter assembly (12) includes a first filter screen (121), a second filter screen (122), a third filter screen (123), and a separation membrane (124). The housing (11) has an oil inlet (112), an oil outlet (113), and a water outlet (114). The oil inlet (112) is used to supply hydraulic oil. The first filter screen (121) is positioned opposite the oil inlet (112). The first filter screen (121), the second filter screen (122), the third filter screen (123), and the third filter screen (124) are connected to the filter assembly (124). The second filter screen (122), the third filter screen (123), and the separation membrane (124) are arranged sequentially away from the oil inlet (112) and filter the hydraulic oil step by step. The first filter screen (121) is used to filter coarse impurities in the hydraulic oil, the second filter screen (122) is used to filter and adsorb metal particles in the hydraulic oil, the third filter screen (123) is used to filter fine impurities in the hydraulic oil, the separation membrane (124) is used to filter and separate water in the hydraulic oil, the oil outlet (113) is used to discharge the filtered and separated hydraulic oil, and the water outlet (114) is used to discharge the separated water.

2. The hydraulic oil filtering device according to claim 1, characterized in that, The first filter screen (121) is a stainless steel filter screen, the second filter screen (122) is a magnetic filter screen composed of magnetic materials and barrier filter screens, and the third filter screen (123) is a copper mesh.

3. The hydraulic oil filtering device according to claim 1, characterized in that, The separation membrane (124) includes a hydrophilic separation membrane (1241) and an oleophilic separation membrane (1242). The hydrophilic separation membrane (1241) allows water to pass through, and the oleophilic separation membrane (1242) allows hydraulic oil to pass through. The hydrophilic separation membrane (1241) is disposed corresponding to the water outlet (114) and is connected to the water outlet (114). The oleophilic separation membrane (1242) is disposed corresponding to the oil outlet (113) and is connected to the oil outlet (113).

4. The hydraulic oil filtering device according to claim 3, characterized in that, The accommodating cavity (111) is also provided with a semi-circular partition (125), which is located below the third filter screen (123). The hydrophilic separation membrane (1241) and the oleophilic separation membrane (1242) are both inclined toward the semi-circular partition (125) in the accommodating cavity (111) and are both connected to the semi-circular partition (125). The hydrophilic separation membrane (1241) and the oleophilic separation membrane (1242) intersect to form an included angle, which is 30°~90°.

5. The hydraulic oil filtering device according to claim 4, characterized in that, The housing (11) includes an upper cover (115), a cylindrical part (116), and a lower cover (117). The upper cover (115) is located at one end of the cylindrical part (116), and the lower cover (117) is located at the other end of the cylindrical part (116). The upper cover (115) and the lower cover (117) are both sealed to the cylindrical part (116) to form the accommodating cavity (111). The upper cover (115) has an oil inlet (112). The cross-sectional area of ​​the cylindrical part (116) decreases from the upper cover (115) toward the semi-circular partition (125) and increases from the semi-circular partition (125) toward the lower cover (117).

6. The hydraulic oil filtering device according to claim 5, characterized in that, The hydraulic oil filtration device also includes a heating device (14), which is located in the accommodating cavity (111) and fixedly installed on the upper cover (115). The heating device (14) is used to heat the hydraulic oil so that the hydraulic oil is maintained at a preset temperature.

7. The hydraulic oil filtering device according to claim 5, characterized in that, The hydraulic oil filtration device also includes a pressure gauge (15) and a differential pressure transmitter (16). The pressure gauge (15) is located in the accommodating cavity (111) and is fixedly connected to the cylindrical part (116). The pressure gauge (15) is used to monitor the working pressure and the degree of contamination of the filter assembly (12). The differential pressure transmitter (16) is fixedly installed in the cylindrical part (116) and is used to monitor the replacement time of the first filter screen (121), the second filter screen (122) and the third filter screen (123).

8. The hydraulic oil filtering device according to claim 5, characterized in that, The hydraulic oil filtration device also includes a cylinder (17) and a trolley (18). The housing (11) is installed inside the cylinder (17), and the cylinder (17) is installed on the trolley (18). The trolley (18) can be moved to a designated position.

9. The hydraulic oil filtering device according to claim 5, characterized in that, The hydraulic oil filtration device also includes an air filter (21), which is fixedly installed on the upper cover (115) for discharging air.

10. The hydraulic oil filtering device according to any one of claims 1-9, characterized in that, The hydraulic oil filtration device also includes a power assembly (13), which provides power to allow the hydraulic oil to enter from the inlet (112) and exit from the outlet (113).

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