A hydraulic filter and hydraulic system

Abstract

This application discloses a hydraulic filter and a hydraulic system, solving the technical problem of hydraulic system operation being affected by contamination in existing technologies. The hydraulic filter includes a filtration system, a first branch, a second branch, a first differential pressure alarm, a second differential pressure alarm, a moisture detector, and a controller. The filtration system includes a first filter and a second filter connected in parallel. The first branch is equipped with a first check valve and a second check valve; the second branch is equipped with a third check valve and a fourth check valve. The first differential pressure alarm is located on the first filter, and the second differential pressure alarm is located on the second filter. The controller is connected to the first differential pressure alarm, the second differential pressure alarm, and the moisture detector. The hydraulic fluid of this application can enter the filtration system bidirectionally via either the first or second branch, and can promptly identify and switch faulty filters, preventing contamination of the hydraulic system and ensuring the normal operation of the entire hydraulic system.

Description

Technical Field

[0001] This application belongs to the field of hydraulic system technology, specifically relating to a hydraulic filter and a hydraulic system. Background Technology

[0002] Hydraulic technology is increasingly widely used in industry. Statistics show that 70-80% of hydraulic system failures are due to cleanliness issues, making filtration devices particularly important. Filtration devices are common auxiliary components in hydraulic systems, used to filter impurities from the hydraulic fluid to improve the cleanliness of the system and ensure stable operation.

[0003] Because of the structural limitations of filter elements, filtration devices are all unidirectional filters, so they are installed on hydraulic lines where the oil flows in one direction only. If the oil in the filter flows in both directions, it will not only fail to filter but will also damage the filter element and contaminate the hydraulic system. Hydraulic cylinders, as the actuators of the hydraulic system, require frequent reciprocating motion. During use, particulate impurities and moisture generated due to wear can contaminate the hydraulic system, causing hydraulic valve jamming. Contamination can only be detected by sampling and testing the hydraulic system, thus preventing timely confirmation of the contamination status. Summary of the Invention

[0004] To solve the above-mentioned technical problems, this application provides a hydraulic filter and a hydraulic system.

[0005] In a first aspect of this application, a hydraulic filter is provided, comprising:

[0006] The filtration system includes a first filter and a second filter connected in parallel;

[0007] The first branch is equipped with a first check valve and a second check valve. The inlet of the first check valve is used to connect with the first return oil line of the hydraulic system, the outlet of the first check valve is connected with the inlet of the filter system, the outlet of the filter system is connected with the inlet of the second check valve, and the outlet of the second check valve is used to connect with the second return oil line of the hydraulic system.

[0008] The second branch is equipped with a third check valve and a fourth check valve. The inlet of the third check valve is used to connect with the second return oil line of the hydraulic system, the outlet of the third check valve is connected with the inlet of the filter system, the outlet of the filter system is connected with the inlet of the fourth check valve, and the outlet of the fourth check valve is used to connect with the first return oil line of the hydraulic system.

[0009] A first differential pressure alarm and a second differential pressure alarm, wherein the first differential pressure alarm is located in the first filter and the second differential pressure alarm is located in the second filter;

[0010] A moisture detection system includes a moisture detector, which is used to be installed in the first return oil line of the hydraulic system or the second return oil line of the hydraulic system;

[0011] The controller is connected to the first differential pressure alarm, the second differential pressure alarm, and the moisture detector.

[0012] In some embodiments, the inlet of the first filter and the inlet of the second filter are also connected in parallel to a bypass line, the bypass line being equipped with a bypass ball valve.

[0013] In some embodiments, the inlet of the filtration system is provided with a first switching ball valve, and the outlet of the filtration system is provided with a second switching ball valve.

[0014] In some embodiments, the filter element of the first filter and / or the filter element of the second filter have a filtration accuracy of 2.5 to 5 μm;

[0015] And / or, the first filter and / or the second filter are monotube filters.

[0016] In some embodiments, the moisture detection system further includes a pressure measuring point and a pressure measuring line, wherein the pressure measuring point is used to be located in the first return oil line of the hydraulic system or the second return oil line of the hydraulic system.

[0017] The moisture meter is connected to the pressure point via the pressure measuring line.

[0018] In some embodiments, the oil drain port of the moisture detector is used to connect to the oil tank.

[0019] In some embodiments, the pressure testing point is a one-way valve, and the hydraulic filter further includes a pin connected to the pressure testing line. The pin cooperates with the one-way valve to allow the first return oil line or the second return oil line to flow into the moisture detector through the pressure testing point.

[0020] In a second aspect of this application, a hydraulic system is provided, comprising:

[0021] The aforementioned hydraulic filter;

[0022] First return oil pipeline and second return oil pipeline;

[0023] An oil tank is used to connect to the first return oil line and / or the second return oil line.

[0024] In some embodiments, the first return oil line is equipped with a first ball valve, and the second return oil line is equipped with a second ball valve.

[0025] In some embodiments, the hydraulic system further includes an integrated valve block in which the first ball valve, the second ball valve, the first check valve, the second check valve, the third check valve, and the fourth single-line valve are all mounted.

[0026] A hydraulic filter and hydraulic system are provided according to one or more embodiments of this application. A hydraulic filter includes a filtration system, a first branch, a second branch, a first differential pressure alarm, a second differential pressure alarm, a moisture detector, and a controller. The filtration system includes a first filter and a second filter connected in parallel. The first branch is equipped with a first check valve and a second check valve. The inlet of the first check valve is connected to the first return oil line of the hydraulic system, and the outlet of the first check valve is connected to the inlet of the filtration system. The outlet of the filtration system is connected to the inlet of the second check valve, and the outlet of the second check valve is connected to the second return oil line of the hydraulic system. The second branch is equipped with a third check valve and a fourth check valve. The inlet of the third check valve is connected to the second return oil line of the hydraulic system, and the outlet of the third check valve is connected to the inlet of the filtration system. The outlet of the filtration system is connected to the inlet of the fourth check valve, and the outlet of the fourth check valve is connected to the first return oil line of the hydraulic system. The first differential pressure alarm and the second differential pressure alarm are located in the first filter and the second differential pressure alarm, respectively. The controller is connected to the first differential pressure alarm, the second differential pressure alarm, and the moisture detector.

[0027] Therefore, the hydraulic fluid in this application can flow through either the first branch or the second branch. In the first branch, the fluid can flow in through the first return line, through the first check valve, the inlet of the filter system, the second check valve, and the second return line. Alternatively, it can flow in through the second return line, through the third check valve, the inlet of the filter system, the fourth check valve, and the first return line. The first, second, third, and fourth check valves are arranged in a bridge configuration, ensuring that the fluid flows through the filter system in the same direction. Regardless of the direction from which the fluid flows in, it will always flow through the filter system inlet in the same direction, thus achieving bidirectional filtration and preventing damage to the filter system due to unidirectional filtration. Furthermore, by setting up the first and second filters, the first and second pressure sensors can promptly detect faulty filters in the system and switch them in time, preventing contamination of the hydraulic system and ensuring the normal operation of the entire hydraulic system. Attached Figure Description

[0028] Figure 1 A schematic diagram of the hydraulic system in one or more embodiments of this application is shown.

[0029] Figure 2 It shows Figure 1 A schematic diagram of the hydraulic filter connection.

[0030] Explanation of reference numerals in the attached diagram: 100-Hydraulic filter, 110-Filtration system, 111-First filter, 112-Second filter, 120-First branch, 121-First check valve, 122-Second check valve, 130-Second branch, 131-Third check valve, 132-Fourth check valve, 140-First differential pressure alarm, 141-Second differential pressure alarm, 150-Bypass ball valve, 160-First switching ball valve, 161-Second switching ball valve, 170-Moisture analyzer, 171-Pressure measuring point, 172-Pressure measuring line, 200-Hydraulic system, 210-First return oil line, 211-First ball valve, 220-Second return oil line, 221-Second ball valve, 230-Oil tank. Detailed Implementation

[0031] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] Please see Figure 1 and Figure 2According to a first aspect of this application, a hydraulic filter 100 is provided, including a filtration system 110, a first branch 120, a second branch 130, a first differential pressure alarm 140, a second differential pressure alarm 141, a moisture detector 170, and a controller. The filtration system 110 includes a first filter 111 and a second filter 112 connected in parallel. The first branch 120 is provided with a first check valve 121 and a second check valve 122. The inlet of the first check valve 121 is connected to the first return oil line 210 of the hydraulic system 200, and the outlet of the first check valve 121 is connected to the inlet of the filtration system 110. The outlet of the filtration system 110 is connected to the inlet of the second check valve 122, and the outlet of the second check valve 122 is connected to the second return oil line 220 of the hydraulic system 200. The second branch 130 is provided with a third check valve 13. The inlet of the third check valve 131 is connected to the second return oil line 220 of the hydraulic system 200, and the outlet of the third check valve 131 is connected to the inlet of the filter system 110. The outlet of the filter system 110 is connected to the inlet of the fourth check valve 132, and the outlet of the fourth check valve 132 is connected to the first return oil line 210 of the hydraulic system 200. A first differential pressure alarm 140 and a second differential pressure alarm 141 are also connected. The first differential pressure alarm 140 is located in the first filter 111, and the second differential pressure alarm 141 is located in the second filter 112. A moisture detector 170 is installed in either the first return oil line 210 or the second return oil line 220 of the hydraulic system 200. A controller is connected to the first differential pressure alarm 140, the second differential pressure alarm 141, and the moisture detector 170.

[0033] The filtration system 110 consists of a first filter 111 and a second filter 112, one in use and one on standby. When the differential pressure alarm of one filter is triggered, it switches to the other filter, thus realizing the switching of the standby filter. At this time, the faulty filter can be repaired, which is convenient and avoids the contamination of the hydraulic system 200 due to filter failure. It can also promptly identify the faulty filter in the system and switch it in time to prevent the hydraulic system 200 from being contaminated. The moisture detector 170 can measure whether there is still moisture in the first return oil line 210 or the second return oil line 220, that is, it can detect the moisture content in the hydraulic system 200. The moisture detector 170 can transmit the detection signal to the controller to determine whether the oil contains water.

[0034] Therefore, this application can achieve two-chamber oil filtration, and at the same time detect the pressure difference of the filter and switch it in time to avoid the contamination of the hydraulic system 200 due to filter failure. The water content in the hydraulic system 200 can be detected by the moisture detector 170, and the status of the hydraulic cylinder can be monitored in real time. This provides a basis for the formulation of hydraulic cylinder maintenance and repair projects, and ensures the normal operation of the entire hydraulic system 200.

[0035] In some embodiments, the first pressure sensor and the second pressure sensor are used to monitor pressure changes before and after the filter, to monitor the filter pressure difference, and to determine the degree of blockage. The first pressure sensor can be installed at the oil inlet or outlet of the first filter 111 or inside the first filter 111, and the second pressure sensor can be installed at the oil inlet or outlet of the second filter 112 or inside the second filter 112.

[0036] In this application, the hydraulic fluid in the hydraulic system 200 can flow through either the first branch 120 or the second branch 130. In the first branch 120, the fluid can flow in through the first return line 210, through the first check valve 121, the inlet of the filter system 110, the second check valve 122, and the second return line 220. Alternatively, it can flow in through the second return line 220, through the third check valve 131, the inlet of the filter system 110, the fourth check valve 132, and the first return line 210. The first check valve 121, the second check valve 122, the third check valve 131, and the fourth check valve 132 are arranged in a bridge configuration to ensure that the fluid flows through the filter system 110 in the same direction. Regardless of the direction from which the fluid flows in, it will always flow through the inlet of the filter system 110 in the same direction, thus achieving bidirectional filtration and preventing damage to the filter system 110 due to unidirectional filtration. Furthermore, by setting up the first filter 111 and the second filter 112, the first pressure sensor and the second pressure sensor can promptly detect the faulty filter in the system and switch it in time, preventing the hydraulic system 200 from being contaminated and ensuring the normal operation of the entire hydraulic system 200.

[0037] In some embodiments, a bypass line is connected in parallel to the inlet of the first filter 111 and the inlet of the second filter 112, and the bypass line is equipped with a bypass ball valve 150. The bypass ball valve 150 is used to connect the first filter 111 and the second filter 112 and is normally closed. When one of the filters fails and needs to be switched, the bypass ball valve 150 is opened, the filter is switched, and the bypass ball valve 150 is closed after the switch. The bypass ball valve 150 is used to balance the pressure between the two filters before switching the filters via the switching ball valve. Opening the bypass ball valve 150 to balance the pressure of the two filters before switching the filters avoids the situation where the switching ball valve cannot rotate due to the pressure difference between the two filters.

[0038] In some embodiments, the inlet of the filtration system 110 is provided with a first switching ball valve 160, and the outlet of the filtration system 110 is provided with a second switching ball valve 161. The first switching ball valve 160 and the second switching ball valve 161 can be used to switch between the first filter 111 and the second filter 112.

[0039] In some embodiments, the filter element of the first filter 111 and / or the filter element of the second filter 112 has a filtration accuracy of 2.5–5 μm; the filtration accuracy can be 2.5 μm, 3 μm, 3.9 μm, 4 μm, 4.5 μm, or 5 μm. It can intercept most solid particulate impurities with a diameter greater than or equal to 2.5 micrometers, such as metal shavings, dust, and sludge, ensuring the cleanliness of the hydraulic oil and reducing the adverse effects of impurities on the hydraulic system 200. It effectively filters out larger impurity particles that may cause wear and damage to hydraulic components without over-filtration, which would increase filtration resistance and reduce the fluidity of the hydraulic oil, thus ensuring the normal operation and efficiency of the hydraulic system 200.

[0040] In some embodiments, the first filter 111 and / or the second filter 112 are single-cylinder filters. A single-cylinder filter is a simple and efficient filtration device. It consists of a single filter cylinder as its main body, with replaceable filter elements housed inside. The single-cylinder filter has an oil inlet and an oil outlet, and its outer shell can be made of robust metal to ensure stable operation under the high-pressure environment of the hydraulic system 200. In the hydraulic system 200, the single-cylinder filter plays a crucial role, effectively intercepting impurities and contaminants in the hydraulic fluid, ensuring the cleanliness of the fluid, thereby improving the overall performance and reliability of the system, extending the service life of hydraulic components, reducing the risk of system failure, and ensuring continuous and stable system operation.

[0041] Therefore, after the filtration system 110 detects an alarm, it is necessary to switch to the backup filter. For example, switching from the first filter 111 to the second filter 112, the switching process is as follows:

[0042] (1) First, the first differential pressure alarm 140 was detected.

[0043] (2) Open the bypass ball valve 150.

[0044] (3) When the first switching ball valve 160 and the second switching ball valve 161 are both rotated 90°, the first switching ball valve 160 and the second switching ball valve 161 are switched from being connected to the first filter 111 to being connected to the second filter 112.

[0045] (4) Close the bypass ball valve 150.

[0046] In some embodiments, the hydraulic filter 100 further includes a pressure measuring point 171 and a pressure measuring line 172. The pressure measuring point 171 is located in the first return oil line 210 or the second return oil line 220 of the hydraulic system 200. The moisture detector 170 is connected to the pressure measuring point 171 via the pressure measuring line 172. This allows for timely measurement of whether the first return oil line 210 or the second return oil line 220 contains moisture, preventing contamination of the hydraulic system 200 due to moisture.

[0047] In some embodiments, the drain port of the moisture detector 170 is connected to the oil tank 230. The moisture detector 170 is used to detect the moisture content in the hydraulic system 200. An alarm is triggered if the moisture content exceeds a set value, for example, 0.03% to 0.05%. The set value can be 0.03%, 0.04%, or 0.05%, and different alarm values ​​can be set according to different operating requirements. An alarm from the moisture detector 170 indicates that the oil contains a certain amount of moisture, generally indicating water ingress into the hydraulic cylinder, thus enabling timely detection of water ingress into the system.

[0048] In some implementations, pressure testing point 171 is a one-way valve. The hydraulic filter 100 also includes a pin connected to pressure testing line 172. The pin cooperates with the one-way valve to allow the first return oil line 210 or the second return oil line 220 to flow into the moisture detector 170 through pressure testing point 171. This ensures that the first return oil line 210 or the second return oil line 220 flows into the moisture detector 170 through pressure testing point 171, and that the measured oil returns to the oil tank 230. The measured oil can smoothly return to the oil tank 230, achieving recycling and ensuring the normal operation of the hydraulic system 200 and the continuity of oil supply.

[0049] In some embodiments, the alarm pressure setting value of the first differential pressure alarm 140 and / or the second differential pressure alarm 141 ranges from 0.1 bar to 180 bar. The first differential pressure alarm 140 and the second differential pressure alarm 141 are used to alarm the first filter 111 and the second filter 112, respectively. The differential pressure alarm starts to sound when the pressure difference across the filter reaches the set value. One differential pressure alarm is installed for each filter. The alarm pressure setting value of the differential pressure alarm is generally divided into four levels: Level 1 (1 ± 0.1 bar), Level 2 (3 ± 0.2 bar), Level 3 (5 ± 0.5 bar), and Level 4 (10 ± 1 bar). Level 1 is selected for system pressure ≤ 10 bar, Level 2 for 10 bar < system pressure ≤ 40 bar, Level 3 for 40 bar < system pressure ≤ 160 bar, and Level 4 for system pressure > 160 bar. The differential pressure alarm can also be set to a differential pressure alarm value other than the four levels according to different working requirements, filter element accuracy level, and pressure level, but this must not affect the filter's performance. The specifications and models of the differential pressure alarm should be matched with the selection of filters and filter elements.

[0050] Therefore, when the pressure difference across the filter element in the filter system reaches the set value, the differential pressure alarm will sound, indicating that the filter element is clogged and needs to be replaced. When the water content in the oil reaches the alarm value, the moisture detector at 170 will sound, which can detect water ingress into the hydraulic system at 200 in advance. By inspecting the filter element after it has been removed from the machine to confirm the form of contaminants, the location of the hydraulic cylinder damage can be determined. Based on the moisture detection value, the extent of water ingress into the hydraulic cylinder can be determined, thus providing a basis for the formulation of hydraulic cylinder maintenance and repair projects.

[0051] In a second aspect of this application, a hydraulic system 200 is provided, including the aforementioned hydraulic filter 100, a first return oil line 210, a second return oil line 220, and an oil tank 230, wherein the oil tank 230 is connected to the first return oil line 210 and / or the second return oil line 220. Oil in the oil tank 230 can enter the hydraulic filter 100 via the first return oil line 210 and then flow out through the second return oil line 220. Alternatively, oil can enter the hydraulic filter 100 via the second return oil line 220 and then flow out through the first return oil line 210.

[0052] In some embodiments, the first return line 210 is provided with a first ball valve 211, and the second return line 220 is provided with a second ball valve 221. The first ball valve 211 and the second ball valve 221 are used to isolate the hydraulic system 200. When the first ball valve 211 and the second ball valve 221 are open, they connect to the hydraulic system 200; when the first ball valve 211 and the second ball valve 221 are closed, they isolate the hydraulic system 200. In addition, closing the first ball valve 211 and the second ball valve 221 can be used for replacing hydraulic components in the device during maintenance.

[0053] In some embodiments, the hydraulic filter 100 is installed in a tubular manner, that is, with the filter system 110 as the main installation body, the first ball valve 211, the second ball valve 221, the first check valve 121, the second check valve 122, the third check valve 131 and the fourth single-line valve are selected as tubular components and are connected to the filter system 110, the hydraulic cylinder and the control valve console through hydraulic pipelines according to their functions.

[0054] In some embodiments, the hydraulic system 200 further includes an integrated valve block, on which a first ball valve 211, a second ball valve 221, a first check valve 121, a second check valve 122, a third check valve 131, and a fourth single-line valve are all mounted. The first ball valve 211, the second ball valve 221, the first check valve 121, the second check valve 122, the third check valve 131, and the fourth single-line valve are selected as plate-type components and integrated onto an integrated valve block, which is then connected to the filtration system 110. In other embodiments, the first ball valve 211, the second ball valve 221, the first check valve 121, the second check valve 122, the third check valve 131, and the fourth single-line valve may also be integrated onto an integrated valve block along with the hydraulic valves controlling the hydraulic cylinder.

[0055] Therefore, the hydraulic system 200 of this application can flow in both directions, reducing contamination of the hydraulic system 200, realizing bidirectional oil filtration and pressure difference and moisture detection functions, extending the service life of the high-precision control valve, timely detecting potential problems in the hydraulic cylinder, and providing a basis for the formulation of hydraulic cylinder maintenance and repair projects.

[0056] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0058] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0059] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0060] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A hydraulic filter, characterized by, include: The filtration system includes a first filter and a second filter connected in parallel; The first branch is equipped with a first check valve and a second check valve. The inlet of the first check valve is used to connect with the first return oil line of the hydraulic system, the outlet of the first check valve is connected with the inlet of the filter system, the outlet of the filter system is connected with the inlet of the second check valve, and the outlet of the second check valve is used to connect with the second return oil line of the hydraulic system. The second branch is equipped with a third check valve and a fourth check valve. The inlet of the third check valve is used to connect with the second return oil line of the hydraulic system, the outlet of the third check valve is connected with the inlet of the filter system, the outlet of the filter system is connected with the inlet of the fourth check valve, and the outlet of the fourth check valve is used to connect with the first return oil line of the hydraulic system. A first differential pressure alarm and a second differential pressure alarm, wherein the first differential pressure alarm is located in the first filter and the second differential pressure alarm is located in the second filter; A moisture analyzer, wherein the moisture analyzer is installed in the first return oil line of the hydraulic system or the second return oil line of the hydraulic system; The controller is connected to the first differential pressure alarm, the second differential pressure alarm, and the moisture detector.

2. The hydraulic filter of claim 1, wherein, The inlet of the first filter and the inlet of the second filter are also connected in parallel to a bypass pipeline, and the bypass pipeline is equipped with a bypass ball valve.

3. The hydraulic filter of claim 1, wherein, The filtration system is equipped with a first switching ball valve at its inlet and a second switching ball valve at its outlet.

4. The hydraulic filter of claim 1, wherein, The filtration accuracy of the filter element of the first filter and / or the filter element of the second filter is 2.5 to 5 μm; And / or, the first filter and / or the second filter are monotube filters.

5. Hydraulic filter according to any of claims 1-4, characterized in that The hydraulic filter also includes a pressure testing point and a pressure testing line, wherein the pressure testing point is used to be located in the first return oil line of the hydraulic system or the second return oil line of the hydraulic system; The moisture meter is connected to the pressure point via the pressure measuring line.

6. The hydraulic filter of claim 5, wherein, The oil drain port of the moisture analyzer is used to connect to the oil tank.

7. The hydraulic filter of claim 5, wherein, The pressure testing point is a one-way valve, and the hydraulic filter also includes a pin connected to the pressure testing line. The pin cooperates with the one-way valve to allow the first return oil line or the second return oil line to flow into the moisture detector through the pressure testing point.

8. A hydraulic system characterized by, include: The hydraulic filter according to any one of claims 1-7; First return oil pipeline and second return oil pipeline; An oil tank is used to connect to the first return oil line and / or the second return oil line.

9. The hydraulic system of claim 8, wherein, The first return oil line is equipped with a first ball valve, and the second return oil line is equipped with a second ball valve.

10. The hydraulic system of claim 9, wherein, The hydraulic system also includes an integrated valve block, on which the first ball valve, the second ball valve, the first check valve, the second check valve, the third check valve, and the fourth check valve are all mounted.

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