Density-based cavitation detection device and method for pure water hydraulic system

Abstract

A density-based cavitation detection device for a pure water hydraulic system, relating to the technical field of pure water hydraulic systems. The device comprises: a pipe body (1) used for conveying a fluid medium; a detection mechanism (3) arranged on the pipe body (1), a detection end of the detection mechanism (3) being configured to be in intermittent contact with the fluid medium to obtain a cavitation signal of the fluid medium; and a blocking mechanism (4) in sliding fit inside the pipe body (1), the blocking mechanism (4) being configured to enable the pipe body (1) and the detection mechanism (3) to intermittently switch between a blocked state and a connected state. By intermittently performing cavitation detection, the effect of long-time hydraulic shock on the detection device is reduced, and the accuracy of cavitation detection is improved.

Description

A density-based cavitation detection device and method for pure water hydraulic system Technical Field

[0001] The present invention belongs to the technical field of pure water hydraulic systems, and in particular relates to a density-based cavitation detection device and method for pure water hydraulic systems. Background Art

[0002] Hydraulic transmission uses liquid as the working medium to transfer, exchange, and control energy. Hydraulic and pneumatic transmission, also known as fluid transmission, are emerging technologies developed based on the principle of hydrostatic pressure transmission proposed by Pascal in the 17th century. It is widely used in engineering machinery, construction machinery, agricultural machinery, metallurgical machinery, mining machinery, and space launches. The level of fluid transmission technology has become a key indicator of industrial development.

[0003] Since pure water has many advantages, such as easy access, low price, no pollution, no combustion, small compression coefficient, and can replace mineral oil in various fields, pure water hydraulic transmission is attracting more and more attention.

[0004] However, the air separation pressure of pure water is higher than that of traditional mineral oil, and under the same conditions, it contains more air than traditional mineral oil. This makes the pure water hydraulic system more prone to cavitation than the traditional hydraulic oil hydraulic system.

[0005] Cavitation is the surface deformation and material erosion that occurs when an object in liquid motion is impacted by cavitation, also known as erosion or cavitation. During cavitation, bubbles rapidly form, expand, and collapse, forming shock waves or high-speed microjets in the liquid. When metal materials are impacted, the surface crystal structure is distorted, leading to chemical instability and different electrical potentials between adjacent grains, thus accelerating the electrochemical corrosion process. The mechanical properties of the material in the eroded area deteriorate significantly, resulting in a dramatic increase in the amount of cavitation. In the design of pure water hydraulic systems, model testing and measures must be conducted in advance to minimize cavitation. To avoid cavitation, it is necessary to first detect the presence and extent of cavitation. Currently, common cavitation detection methods typically use long-term continuous detection. When cavitation occurs, the detection device's detection accuracy is easily reduced due to the prolonged hydraulic shock, resulting in small fluctuations in the detection signal. Therefore, a density-based cavitation detection device and method for pure water hydraulic systems is urgently needed to address this issue.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to provide a density-based pure water hydraulic system cavitation detection device and method to solve the above problems. By performing cavitation detection at intervals, the impact of long-term hydraulic shock on the detection device is reduced, and the accuracy of cavitation detection is improved.

[0008] To achieve the above objectives, the present invention provides the following solution: a density-based cavitation detection device for a pure water hydraulic system, comprising:

[0009] The pipe body is used for conveying fluid medium;

[0010] a detection mechanism, disposed on the tube body, wherein a detection end of the detection mechanism is configured to intermittently contact the fluid medium to obtain a cavitation signal of the fluid medium;

[0011] The blocking mechanism is slidably fitted in the tube body, and the blocking mechanism is configured to be able to intermittently switch the blocking / connection state between the tube body and the detection mechanism through the hydraulic action generated by the fluid medium.

[0012] Preferably, it also includes:

[0013] a control mechanism, wherein a control section communicating with the tube body is formed in the control mechanism;

[0014] When the tube conveys a fluid medium, causing the hydraulic pressure to be formed in the control interval, the hydraulic pressure is configured to cause the blocking mechanism to move in a first direction to block the tube, and the hydraulic pressure cooperates with the control end of the control mechanism to contact the detection end;

[0015] When the blocking mechanism blocks the tube body, causing the hydraulic pressure in the control zone to decompose, the blocking mechanism can move in a second direction opposite to the first direction to connect the tube body with the control zone.

[0016] Preferably, the control mechanism includes:

[0017] a first cylinder, wherein one end of the inner cavity of the first cylinder is connected to the tube body;

[0018] a control member, slidably fitted in the first cylinder, wherein a control end of the control member extends out of the first cylinder along the other end away from the tube body through the hydraulic pressure and contacts the detection end;

[0019] The communicating pipe is connected to the first cylinder and the blocking mechanism respectively. The inner cavity of the communicating pipe forms a force in the same direction as the first direction through the hydraulic pressure, and acts on the blocking mechanism.

[0020] Preferably, the control element includes:

[0021] a first slider, slidably connected to the first cylinder, a sealing ring being provided on an outer cover of the first slider, the sealing ring being in sliding contact with the inner wall of the first cylinder, a column protrusion being integrally formed on the top end of the first slider, the column protrusion extending out of the first cylinder for contacting the detection end;

[0022] A first spring is wound around the column boss, and two ends of the first spring are respectively fixed to the first sliding block and the inner wall surface of the first cylinder.

[0023] Preferably, the blocking mechanism comprises:

[0024] a second cylinder body, disposed at the front end of the first cylinder body and connected to the pipe body and the connecting pipe respectively;

[0025] a second slider slidably engaged with the second cylinder body, a piston structure being integrally formed on a side of the second slider close to the connecting pipe, and when a force acting in the same direction as the first direction is generated in the connecting pipe, the connecting pipe cooperates with the piston structure to move the second slider in the first direction to block the pipe body;

[0026] A second spring is filled between the piston structure and the connecting pipe, and two ends of the second spring are respectively fixed to the piston mechanism and the inner wall of the second cylinder.

[0027] Preferably, the detection mechanism includes:

[0028] a third cylinder body, arranged on a side close to the control member, wherein a resistance strain gauge is arranged in the third cylinder body;

[0029] The third slider is arranged on the third cylinder body and contacts the resistance strain gauge. One end of the third slider extends out of the third cylinder body to contact the control end.

[0030] Preferably, it also includes:

[0031] An outer cylinder body, and an outer cylinder upper cover and an outer cylinder lower cover detachably connected to the outer cylinder body, the third cylinder body is fixed relative to the outer cylinder body through the outer cylinder upper cover / outer cylinder lower cover, and the tube body is passed through the outer cylinder body and fixed to the outer cylinder body.

[0032] Preferably, the first cylinder body, the second cylinder body and the third cylinder body are all detachable connection structures.

[0033] A density-based pure water hydraulic system cavitation detection method, based on the above-mentioned density-based pure water hydraulic system cavitation detection device, includes the following steps:

[0034] Connect the pipe body to convey the fluid medium, so that the fluid medium flows into the control zone;

[0035] The hydraulic pressure generated in the control range is applied to the first slider and the second slider respectively;

[0036] The first slider is brought into contact with the third slider, and a hydraulic pressure signal is obtained through a detection mechanism;

[0037] By driving the second slider to block the pipe body, the hydraulic pressure in the control area is decomposed;

[0038] After the hydraulic pressure is lost, the second spring resets the second slider to connect the tube body with the control zone, and the step of allowing the fluid medium to flow into the control zone is repeated;

[0039] The obtained hydraulic signals are taken as the mean value of the signal peak value per unit time m, and the lowest value of the signal peak value is n. When n is less than 0.98m, cavitation is determined to have occurred, otherwise it is considered that cavitation has not occurred.

[0040] Compared with the prior art, the present invention has the following advantages and technical effects:

[0041] The present invention introduces a fluid medium into the tube body through an external hydraulic system, so that the fluid medium is introduced into the detection mechanism at a certain pressure, and the detection end of the detection mechanism is intermittently in contact with the fluid medium, thereby obtaining hydraulic information of the fluid medium, and a blocking mechanism that slides with the corresponding tube body is provided. The blocking mechanism intermittently controls the connection or blocking state between the tube body and the detection mechanism, thereby achieving intermittent contact between the detection end of the detection mechanism and the fluid medium, reducing fatigue loss of the detection mechanism caused by long-term hydraulic shock, and improving the detection accuracy of cavitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0043] Figure 1 is a diagram showing the positional relationship between the outer cylinder and the overall device;

[0044] FIG2 is a diagram showing the positional relationship between the blocking mechanism and the tube body;

[0045] FIG3 is a cross-sectional view of the structure of the first slider and the first cylinder;

[0046] FIG4 is a cross-sectional view of the structure of the second slider and the second cylinder;

[0047] FIG5 is a cross-sectional view of the structure of the third slider and the third cylinder;

[0048] Among them, 1. Tube body; 2. Control mechanism; 21. First cylinder body; 22. First slider; 23. Connecting pipe; 24. First spring; 25. Column boss; 26. Sealing ring; 3. Detection mechanism; 31. Third cylinder body; 32. Third slider; 33. Resistance strain gauge; 4. Blocking mechanism; 41. Second cylinder body; 42. Second slider; 43. Second spring; 44. Piston structure; 5. Outer cylinder body; 6. Outer cylinder upper cover; 7. Outer cylinder lower cover. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Embodiment: Referring to Figures 1-5, a density-based cavitation detection device for a pure water hydraulic system includes:

[0052] Tube body 1, used for conveying fluid medium;

[0053] The detection mechanism 3 is arranged on the tube body 1, and the detection end of the detection mechanism 3 is configured to intermittently contact the fluid medium to obtain a cavitation signal of the fluid medium;

[0054] The blocking mechanism 4 is slidably fitted in the tube body 1 . The blocking mechanism 4 is configured to be able to intermittently switch the blocking / connection state between the tube body 1 and the detection mechanism 3 through the hydraulic action generated by the fluid medium.

[0055] The present invention introduces a fluid medium into the tube body 1 through an external hydraulic system, so that the fluid medium is introduced into the detection mechanism 3 at a certain pressure, and the detection end of the detection mechanism 3 is intermittently in contact with the fluid medium, thereby obtaining hydraulic information of the fluid medium, and a blocking mechanism 4 is provided corresponding to the tube body 1 and slidably cooperates with it. The blocking mechanism 4 intermittently controls the connection or blocking state between the tube body 1 and the detection mechanism 3, thereby achieving intermittent contact between the detection end of the detection mechanism 3 and the fluid medium, reducing fatigue loss of the detection mechanism 3 caused by long-term hydraulic shock, and improving the detection accuracy of cavitation.

[0056] In the present technical solution, the blocking mechanism 4 can adopt a common electric valve, and use a timer or other timing control device to control the intermittent opening and closing of the electric valve to achieve intermittent connectivity between the tube body 1 and the detection mechanism 3. In addition, the detection mechanism 3 obtains the hydraulic signal, preferably but not limited to using a pressure sensing method, a displacement detection method, etc. When the fluid medium enters the detection mechanism 3 and contacts the detection end, the detection end detects the pressure change and displacement to generate a signal, which can be used as information for obtaining the hydraulic signal to determine the occurrence of cavitation.

[0057] Furthermore, it also includes:

[0058] The control mechanism 2 has a control section formed therein that communicates with the tube body 1;

[0059] When the pipe body 1 conveys a fluid medium, causing hydraulic pressure to be formed in the control interval, the hydraulic pressure is configured to cause the blocking mechanism 4 to move in a first direction to block the pipe body 1, and the hydraulic pressure cooperates with the control end of the control mechanism 2 to contact the detection end;

[0060] When the blocking mechanism 4 blocks the pipe body 1 and causes the hydraulic pressure in the control zone to decompose, the blocking mechanism 4 can move in a second direction opposite to the first direction to connect the pipe body 1 with the control zone.

[0061] A control mechanism 2 is provided between the tube body 1 and the detection mechanism 3. Through the control interval formed in the control mechanism 2, the control interval is utilized to contain the fluid medium, and as the tube body 1 is connected with the control interval, hydraulic pressure is formed in the control interval. When the hydraulic pressure generates a force sufficient to move the blocking mechanism 4 along the first direction, the blocking mechanism 4 can move along the first direction to block the tube body 1. After the tube body 1 is blocked, the control interval loses the pressure of the fluid medium continuously introduced from the tube body 1, causing the hydraulic pressure to decompose, thereby utilizing the blocking mechanism 4 to move along the second direction to cause the tube body 1 to be re-connected with the control interval. After the fluid medium continues to be introduced into the tube body 1, the control interval is repeatedly and intermittently filled with the fluid medium to form hydraulic pressure, and the fluid medium is detected through contact between the hydraulic pressure and the control and detection ends of the control mechanism 2.

[0062] It can be understood that when the hydraulic pressure is filled to a certain level and the force generated is certain, the blocking mechanism 4 moves along the first direction under the influence of the force to block the tube body 1, thereby effectively ensuring the amount of fluid medium contained in the control range and the relative stability of the hydraulic detection results, and effectively improving the accuracy of the detection of cavitation in the fluid medium.

[0063] Furthermore, the control mechanism 2 includes:

[0064] A first cylinder 21, one end of the inner cavity of the first cylinder 21 is connected to the tube 1;

[0065] The control member is slidably fitted in the first cylinder 21. The control end of the control member extends out of the first cylinder 21 along the other end away from the tube body 1 through hydraulic pressure and contacts the detection end.

[0066] The communicating tube 23 is communicated with the first cylinder 21 and the blocking mechanism 4 respectively. The inner cavity of the communicating tube 23 is hydraulically provided with a force in the same direction as the first direction, and acts on the blocking mechanism 4 .

[0067] By utilizing a control member that is slidably fitted in the first cylinder 21, the control member is connected to the tube body 1 through the first cylinder 21. When the tube body 1 transports the fluid medium, the fluid medium is introduced into the first cylinder 21. The hydraulic pressure formed cooperates with the control end of the control member to extend out of the first cylinder 21 and contact the detection end, thereby obtaining the hydraulic signal. Moreover, when the hydraulic pressure is applied, the fluid medium is introduced into the connecting pipe 23, and under the influence of the weight of the liquid medium and the hydraulic pressure, an action in the same direction as the first direction is generated in the connecting pipe 23 and acts on the blocking mechanism 4, thereby enabling the blocking mechanism 4 to move along the first direction to block the tube body 1.

[0068] Furthermore, the control element includes:

[0069] The first slider 22 is slidably connected to the first cylinder 21. A sealing ring 26 is provided on the outer cover of the first slider 22. The sealing ring 26 is in sliding contact with the inner wall of the first cylinder 21. A cylindrical protrusion 25 is integrally formed on the top of the first slider 22. The cylindrical protrusion 25 extends out of the first cylinder 21 to contact the detection end.

[0070] The first spring 24 is wound around the column boss 25 , and both ends of the first spring 24 are fixedly connected to the first slider 22 and the inner wall surface of the first cylinder 21 respectively.

[0071] By sliding the first slider 22 in the first cylinder 21, and the first slider 22 is provided with a sealing ring 26 in contact with the inner wall of the first cylinder 21, the first cylinder 21 and the connecting end of the tube body 1 are sealed. The hydraulic pressure generated by the fluid medium pushes the first slider 22 to make the column boss 25 slide out along the first cylinder 21 and contact the detection end to obtain the hydraulic signal. After the hydraulic pressure is decomposed, the first spring 24 drives the first slider 22 to return to its original position, ensuring that the capacity of the sealed cavity formed in the first cylinder 21 is constant, so that the generation of hydraulic pressure is relatively stable.

[0072] Furthermore, the blocking mechanism 4 includes:

[0073] The second cylinder 41 is provided at the front end of the first cylinder 21 and is connected to the pipe 1 and the connecting pipe 23 respectively;

[0074] The second slider 42 is slidably engaged with the second cylinder 41. A piston structure 44 is integrally formed on the side of the second slider 42 close to the connecting pipe 23. When a force in the same direction as the first direction is generated in the connecting pipe 23, the connecting pipe 23 cooperates with the piston structure 44 to move the second slider 42 in the first direction to block the pipe body 1.

[0075] The second spring 43 is filled between the piston structure 44 and the connecting pipe 23 , and both ends of the second spring 43 are fixedly connected to the piston structure and the inner wall of the second cylinder 41 respectively.

[0076] By connecting one end of the second cylinder 41 with the tube body 1, and the second cylinder 41 is located in the direction of the fluid medium introduced into the first cylinder 21, the other end of the second cylinder 41 is connected with the first cylinder 21 through the connecting pipe 23. As hydraulic pressure is formed in the first cylinder 21, the fluid medium is introduced into the connecting pipe 23, and gravity and hydraulic pressure are accumulated in the connecting pipe 23. When the force exceeds the supporting strength of the second spring 43, the force drives the piston structure 44 to move the second slider 42, so that the second slider 42 extends out of the second cylinder 41 to block the tube body 1. The first cylinder 21 loses the hydraulic pressure of the continuous introduction of the fluid medium, thereby decomposing the hydraulic pressure in the control range. Under the reset action of the second spring 43, the second slider 42 is lifted to re-connect the tube body 1 with the first cylinder 21, thereby realizing an intermittent switching state.

[0077] Furthermore, the detection mechanism 3 includes:

[0078] The third cylinder 31 is provided on a side close to the control member, and a resistance strain gauge 33 is provided in the third cylinder 31;

[0079] The third slider 32 is disposed on the third cylinder 31 and contacts the resistance strain gauge 33 . One end of the third slider 32 extends out of the third cylinder 31 to contact the control end.

[0080] The fluid medium contained in the first cylinder 21 generates a hydraulic effect, which hydraulically squeezes the first slider 22, driving the column projection 25 to extend out of the first cylinder 21 and contact the third slider 32. The third slider 32 slides along the third cylinder 31 and contacts the resistance strain gauge 33, driving the projection of the resistance strain gauge 33. Then, the resistance strain gauge 33 is reset after the hydraulic pressure disappears. During this process, the resistance strain gauge 33 converts the pressure signal transmitted by the hydraulic pressure into an electrical signal, thereby realizing intermittent detection of hydraulic cavitation.

[0081] It can also be understood that the resistance strain gauge 33 in the third cylinder body 31 can be selectively replaced with a common displacement sensor. By detecting the sliding distance after the third slider 32 contacts the column protrusion 25, the signal of cavitation occurring in the fluid medium can also be obtained to achieve intermittent detection.

[0082] Furthermore, it also includes:

[0083] The outer cylinder body 5, and the outer cylinder upper cover 6 and the outer cylinder lower cover 7 detachably connected to the outer cylinder body 5, the third cylinder body 31 is fixed relative to the outer cylinder body 5 through the outer cylinder upper cover 6 / outer cylinder lower cover 7, and the tube body 1 is passed through the outer cylinder body 5 and fixed to the outer cylinder body 5.

[0084] Furthermore, the first cylinder body 21 , the second cylinder body 41 and the third cylinder body 31 are all detachable connection structures.

[0085] In this technical solution, the outer cylinder body 5 is set to have two inner cavities, one large and one small, and the third cylinder body 31 is covered in the small inner cavity. The outer cylinder cover 6 is threadedly connected to the outer cylinder body 5 by a number of bolts around the outer cylinder cover 6, and the third cylinder body 31 is fixed to the outer cylinder body 5, and the third cylinder body 31 is not connected to the first cylinder body 21. By passing the tube body 1 through the large inner cavity, the connection stability of the tube body 1 and the outer cylinder body 5 is guaranteed by the limiting convex integrally formed on the tube body 1, and the first cylinder body 21 and the second cylinder body 41 are respectively connected and fixed to the tube body 1 through a three-way pipe. The first cylinder body 21, the second cylinder body 41 and the third cylinder body 31 are all split structures up and down, and are detachably connected by bolts. While ensuring the structural sealing, it is also convenient for the disassembly and maintenance of the detection device during actual use, further improving the effect of cavitation detection of fluid media.

[0086] A density-based pure water hydraulic system cavitation detection method, based on the above-mentioned density-based pure water hydraulic system cavitation detection device, includes the following steps:

[0087] Connect the pipe body 1 to convey the fluid medium, so that the fluid medium flows into the control zone;

[0088] The hydraulic pressure formed in the control range is used to contact the first slider 22 and the second slider 42 respectively;

[0089] The first slider 22 is brought into contact with the third slider 32, and a hydraulic signal is obtained through the detection mechanism 3;

[0090] The second slider 42 is driven by hydraulic pressure to block the pipe body 1, so that the hydraulic pressure in the control range is decomposed;

[0091] After the hydraulic pressure is lost, the second spring 43 resets the second slider 42 to connect the tube body 1 with the control zone, and the steps of passing the fluid medium into the control zone are repeated.

[0092] The obtained hydraulic signals are taken as the mean value of the signal peak value per unit time m, and the lowest value of the signal peak value is n. When n is less than 0.98m, cavitation is determined to have occurred, otherwise it is considered that cavitation has not occurred.

[0093] After the fluid medium cavitates in the tube body 1, the density of the fluid medium changes. When entering the first cylinder body 21, the flow rate of the fluid medium and the constant specifications of the first cylinder body 21 and the first slider 22 cause the density of the fluid medium to change, thereby changing the intensity of the hydraulic action on the first slider 22. The forces of different magnitudes driving the first slider 22 to contact the third slider 32 are different, so that the different corresponding electrical signals transmitted on the resistance strain gauge 33 are also different. Then, by hydraulically squeezing the second slider 42 to intermittently block the tube body 1, adaptive adjustment of the hydraulic pressure of the fluid medium is achieved. The resistance strain gauge 33 intermittently detects the hydraulic signal, setting the unit time to ten seconds as an example, and recording the peak value of the resistance strain gauge 33 detected within ten seconds, which is the force of hydraulic squeezing the first slider 22. By comparing the difference between the peak average and the peak minimum, accurate detection of the occurrence of cavitation in the fluid medium is achieved.

[0094] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0095] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A cavitation detection device for a pure water hydraulic system based on density, characterized in that Comprising: A pipe body (1) for conveying a fluid medium; A detection mechanism (3) arranged on the pipe body (1), and a detection end of the detection mechanism (3) is configured to intermittently contact the fluid medium to obtain a cavitation signal of the fluid medium; A blocking mechanism (4) slidably fitted within the pipe body (1), and the blocking mechanism (4) is configured to be able to, through the hydraulic action generated by the fluid medium, intermittently switch the sealing / communication state of the gap between the pipe body (1) and the detection mechanism (3).

2. The cavitation detection device for a pure water hydraulic system based on density according to claim 1, characterized in that, Further comprising: A control mechanism (2) having a control section formed therein that communicates with the pipe body (1); Wherein, when the pipe body (1) conveys a fluid medium, causing the hydraulic pressure to be formed within the control section, the hydraulic pressure is configured to cause the blocking mechanism (4) to move in a first direction to block the pipe body (1), and the hydraulic pressure and a control end of the control mechanism (2) cooperate to contact the detection end; When the blocking mechanism (4) blocks the pipe body (1), causing the hydraulic pressure within the control section to decompose, the blocking mechanism (4) can move in a second direction opposite to the first direction to communicate the pipe body (1) with the control section.

3. The cavitation detection device for a pure water hydraulic system based on density according to claim 2, wherein The control mechanism (2) includes: A first cylinder body (21), one end of the inner cavity of the first cylinder body (21) communicates with the pipe body (1); A control member slidably fitted within the first cylinder body (21), and a control end of the control member extends out of the first cylinder body (21) along the other end away from the pipe body (1) through the hydraulic pressure and contacts the detection end; A communication pipe (23) respectively communicating with the first cylinder body (21) and the blocking mechanism (4), and a force in the same direction as the first direction is formed within the inner cavity of the communication pipe (23) through the hydraulic pressure and acts on the blocking mechanism (4).

4. The cavitation detection device for a pure water hydraulic system based on density according to claim 3, characterized in that, The control member includes: A first slider (22) slidably connected within the first cylinder body (21), a sealing ring (26) is sleeved outside the first slider (22), the sealing ring (26) is in sliding contact with the inner wall of the first cylinder body (21), a columnar protrusion (25) is integrally formed at the top of the first slider (22), and the columnar protrusion (25) extends out of the first cylinder body (21) for contacting the detection end; A first spring (24) wound around the columnar protrusion (25), and two ends of the first spring (24) are respectively fixedly connected to the first slider (22) and the inner wall surface of the first cylinder body (21).

5. The cavitation detection device for a pure water hydraulic system based on density according to claim 3, characterized in that, The blocking mechanism (4) includes: A second cylinder body (41) arranged at the front end of the first cylinder body (21) and respectively communicating with the pipe body (1) and the communication pipe (23); The second slider (42) is slidably fitted on the second cylinder block (41). A piston structure (44) is integrally formed on one side of the second slider (42) close to the communication pipe (23). When a force in the same direction as the first direction is formed in the communication pipe (23), the communication pipe (23) cooperates with the piston structure (44) to enable the second slider (42) to move along the first direction for blocking the pipe body (1). The second spring (43) is filled between the piston structure (44) and the communication pipe (23). Two ends of the second spring (43) are fixedly connected to the piston mechanism and the inner wall of the second cylinder block (41) respectively.

6. The cavitation detection device for a pure water hydraulic system based on density according to claim 5, characterized in that The detection mechanism (3) includes: A third cylinder block (31) is arranged on one side close to the control member. A resistance strain gauge (33) is arranged in the third cylinder block (31). A third slider (32) is arranged on the third cylinder block (31) and contacts with the resistance strain gauge (33). One end of the third slider (32) extends out of the third cylinder block (31) for contacting with the control end.

7. The cavitation detection device for a pure water hydraulic system based on density according to claim 6, characterized in that, It further includes: An outer cylinder body (5), an outer cylinder upper cover (6) and an outer cylinder lower cover (7) detachably connected to the outer cylinder body (5). The third cylinder block (31) is fixed relative to the outer cylinder body (5) through the outer cylinder upper cover (6) / outer cylinder lower cover (7). The pipe body (1) is arranged in the outer cylinder body (5) and fixed to the outer cylinder body (5).

8. The cavitation detection device for a pure water hydraulic system based on density according to claim 6, characterized in that: The first cylinder block (21), the second cylinder block (41) and the third cylinder block (31) are all of detachable connection structures.

9. A density-based cavitation detection method for a pure water hydraulic system, based on the density-based cavitation detection device for a pure water hydraulic system according to any one of claims 1-6, characterized in that, It includes the following steps: Connect the pipe body (1) to convey a fluid medium, and make the fluid medium flow into the control area. Utilize the hydraulic pressure formed in the control area to act on the first slider (22) and the second slider (42) respectively. Make the first slider (22) contact with the third slider (32), and obtain a hydraulic signal through the detection mechanism (3). Block the pipe body (1) by driving the second slider (42), and decompose the hydraulic pressure in the control area. After the hydraulic action is lost, the second spring (43) resets the second slider (42) to connect the pipe body (1) with the control area, and repeat the step of making the fluid medium flow into the control area. Take the mean value of the signal peaks within a unit time for several obtained hydraulic signals as m, and the lowest value of the signal peaks is n. When n < 0.98m, it is determined that cavitation occurs, otherwise it is regarded as no cavitation occurring.

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