Cavitation detection apparatus and method for density-based pure water hydraulic systems

Abstract

The present invention relates to the technical field of pure water hydraulic systems and provides a density-based cavitation detection device for pure water hydraulic systems, including a pipe for transporting a fluid medium, a detection mechanism disposed on the pipe and arranged so that a detection end intermittently contacts the fluid medium to acquire a cavitation signal of the fluid medium, and a blocking mechanism slidably fitted within the pipe and arranged so that the pipe and the detection mechanism can be intermittently switched between a blocked state and a communicating state. By detecting cavitation at intervals, the present invention reduces the impact of long-term hydraulic shock on the detection device and improves the accuracy of cavitation detection.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the technical field of pure water Hydraulic pressure systems, and particularly relates to a cavitation detection apparatus and method for pure water systems based on density. Hydraulic pressure

BACKGROUND ART

[0002] Hydraulic pressure Transmission is a transmission mode that uses liquid as the working medium to transmit, exchange and control energy. Hydraulic pressure Transmission and pneumatic transmission are collectively referred to as fluid transmission, which is a new technology developed based on the principle of hydrostatic transmission proposed by Pascal in the 17th century. It is a technology widely applied in engineering machinery, construction machinery, agricultural machinery, metallurgical machinery, mining machinery, space launch and other fields. At present, the level of fluid transmission technology has become an important symbol indicating the level of industrial development.

[0003] Pure water has many advantages, including convenient material availability, low cost, no pollution, non-combustibility, and a low compression coefficient, and can function in various fields instead of mineral oil. Therefore, pure water Hydraulic pressure transmission has attracted increasing attention.

[0004] However, the air separation pressure of pure water is higher than that of conventional mineral oil, and pure water contains more air than conventional mineral oil under the same conditions. Therefore, pure water Hydraulic pressure systems are more prone to cavitation than conventional working oil hydraulic systems.

[0005] ​Cavitation is a deformation and erosion phenomenon that occurs on the surface of an object after it is subjected to cavitation shock during liquid motion; it is also called erosion or cavitation. During cavitation, cavitation bubbles rapidly form, expand, and collapse, creating surges or high-speed microjet in the liquid. After a metallic material is subjected to shock, the surface crystal structure twists, creating chemical instability, which causes the potential of adjacent crystal grains to differ, accelerating the electrochemical corrosion process. The mechanical properties of the material in the eroded area deteriorate significantly, and the amount of cavitation increases dramatically. Hydraulic pressure In system design, model testing must be conducted beforehand, and measures must be taken to avoid cavitation as much as possible. To avoid cavitation, it is first necessary to detect whether cavitation is occurring and to what extent it is occurring, but currently, common cavitation detection methods usually employ long-term continuous detection. If cavitation occurs, the detection device will continue for a long time. Hydraulic pressure The detection accuracy of cavitation signals is easily reduced by impact, and the fluctuation of the detection signal is small, so to solve the above problem, density-based pure water Hydraulic pressure There is an urgent need for a cavitation detection device and method for the system. [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to solve the above problems and to enable cavitation detection at intervals, thereby reducing the time required for the detection device. Hydraulic pressure Density-based pure water reduces the effects of impact and improves cavitation detection accuracy. Hydraulic pressure The objective is to provide a cavitation detection device and method for a system. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides the following solution: density-based pure water Hydraulic pressure The system's cavitation detection device is A pipe for transferring a fluid medium, A detection mechanism is positioned on the aforementioned pipe, with its detection end intermittently contacting the fluid medium to acquire a cavitation signal of the fluid medium. It is slidable in a first direction for advancing into the tube and in a second direction for retracting out of the tube, and is biased in the second direction. , generated by the fluid medium Hydraulic pressure The action of the tube Blockage / opening It includes a closure mechanism arranged to allow intermittent switching of states.

[0008] Preferably, The fluid medium is positioned downstream of the blocking mechanism in the transfer direction of the fluid medium. A control mechanism is further included, and a control section communicating with the pipe is formed within the control mechanism. Here, the pipe transports the fluid medium, and within the control section Hydraulic pressure When the above is formed, Hydraulic pressure The blocking mechanism The aforementioned The pipe is positioned to be moved in the first direction to close the pipe body, Hydraulic pressure It cooperates with the control end of the control mechanism to contact the detection end, The blocking mechanism blocks the pipe body, and the control section The hydraulic pressure is decreasing. Then, the blocking mechanism is opposite to the first direction The aforementioned Moving in the second direction, the pipe Of the portion located upstream of the blocking mechanism in the transport direction. Connecting the control section Let .

[0009] Preferably, the control mechanism is A first cylinder, one end of which is connected to the pipe body, It is slidably fitted into the first cylinder, and the control end is the Hydraulic pressure A control element extends from the first cylinder along the other end away from the pipe body and contacts the detection end, Each includes a connecting pipe that communicates with the first cylinder and the closing mechanism, and the internal cavity of the connecting pipe is the Hydraulic pressure This generates an action force acting in the same direction as the first direction, which acts on the blocking mechanism.

[0010] Preferably, the control element is a first slider that is in sliding contact with the inside of the first cylinder, a seal ring is fitted around the outer side thereof, the seal ring is in sliding contact with the inner wall of the first cylinder, a column protrusion is integrally formed on the upper portion thereof, and the column protrusion extends out of the first cylinder to come into contact with the detection end; and a first spring wound around the column protrusion, wherein both ends of the first spring are respectively fixed to the first slider and the inner wall surface of the first cylinder.

[0011] Preferably, the blocking mechanism comprises a second cylinder provided at the tip of the first cylinder and respectively communicating with the tubular body and the communication pipe; a second slider that is slidably fitted to the second cylinder, a piston structure is integrally formed on the side close to the communication pipe, and when an acting force in the same direction as the first direction is formed in the communication pipe, the second slider moves in the first direction under the cooperation of the communication pipe and the piston structure to block the tubular body; and a second spring filled between the piston structure and the communication pipe, wherein both ends of the second spring are respectively fixed to the piston mechanism and the inner wall of the second cylinder.

[0012] Preferably, the detection mechanism comprises a third cylinder provided on the side close to the control element, with a resistance strain gauge disposed inside; and a third slider disposed in the third cylinder and in contact with the resistance strain gauge, wherein one end of the third slider extends out of the third cylinder to come into contact with the control end.

[0013] Preferably, an outer cylinder, and an outer cylinder upper cover and an outer cylinder lower cover detachably connected to the outer cylinder are further included, the third cylinder is fixed relative to the outer cylinder by the outer cylinder upper cover / the outer cylinder lower cover, and the tubular body is bored in the outer cylinder and fixed to the outer cylinder.

[0014] Preferably, the first cylinder, the second cylinder, and the third cylinder all have a detachable connection structure.

[0015] Density-based pure water Hydraulic pressure A system cavitation detection method comprises the above density-based pure water Hydraulic pressure Based on the system cavitation detection apparatus, connecting pipes to transfer a fluid medium, and passing the fluid medium through a control section; formed within the control section Hydraulic pressure to act on the first slider and the second slider respectively; bringing the first slider into contact with the third slider, and using a detection mechanism to Hydraulic pressure acquire a signal; driving the second slider to block the pipe, and within the control section Lower the hydraulic pressure step of In response to the decrease in hydraulic pressure within the control section , the second spring resets the second slider to , the portion of the pipe body upstream of the blocking mechanism in the transport direction. communicate with the control section, and the fluid medium is passed into the control section again step of passing Pu and , taking the average value of the acquired several signal peak values within a unit time as value m, taking the minimum value of the signal peak values as n, determining that cavitation is occurring when n < 0.98m, and otherwise considering that cavitation is not occurring. Hydraulic pressure taking the average value of the acquired several signal peak values within a unit time as value m, taking the minimum value of the signal peak values as n, determining that cavitation is occurring when n < 0.98m, and otherwise considering that cavitation is not occurring. Effects of the Invention

[0016] Compared with the prior art, the present invention has the following advantages and technical effects.

[0017] In the present invention, an external Hydraulic pressure system is used to pass the fluid medium through the inside of the pipe, so the fluid medium is passed into the detection mechanism at a constant pressure. By utilizing the intermittent contact between the detection end of the detection mechanism and the fluid medium, the Hydraulic pressure information of the fluid medium is acquired. Further, a blocking mechanism that slides relative to the pipe is provided corresponding to the pipe, and the blocking mechanism 4 Determination to proceed is provided with a corresponding sliding blocking mechanism for the pipe, and the blocking mechanism 4 blocks the Body connection or openingThe state is intermittently controlled, thereby achieving intermittent contact between the detection end of the detection mechanism and the fluid medium, allowing for long-term operation. Hydraulic pressure This reduces fatigue loss to the detection mechanism due to impact and improves the detection accuracy against cavitation. [Brief explanation of the drawing]

[0018] In order to more clearly illustrate embodiments of the present invention or technical solutions in the prior art, the drawings necessary for the embodiments will be briefly described below. However, the drawings in the following description represent only a few embodiments of the present invention, and those skilled in the art can obtain other drawings based on these without expending any creative effort. [Figure 1] This is a diagram showing the relative positions of the outer cylinder and the entire device. [Figure 2] This is a diagram showing the relationship between the occlusion mechanism and the position of the pipe. [Figure 3] This is a structural cross-sectional view of the first slider and the first cylinder. [Figure 4] This is a structural cross-sectional view of the second slider and the second cylinder. [Figure 5] This is a cross-sectional view of the structure of the third slider and the third cylinder. [Modes for carrying out the invention]

[0019] The following describes the technical solutions in embodiments of the present invention clearly and completely with reference to the accompanying drawings, but it is clear that the embodiments described are only a part of the embodiments of the present invention and not all of them. All other embodiments obtained based on the embodiments of the present invention, assuming that a person skilled in the art does not perform any creative work, are within the scope of the protection of the present invention.

[0020] To make the above-mentioned objectives, features, and advantages of the present invention clearer, the present invention will be described in more detail below with reference to the drawings and specific embodiments.

[0021] Examples: Refer to Figures 1 to 5, for pure water based on density. Hydraulic pressure The system's cavitation detection device is A pipe 1 for transferring a fluid medium, A detection mechanism 3 is positioned on the pipe 1, with its detection end intermittently contacting the fluid medium to acquire a cavitation signal from the fluid medium. Sliding inside the pipe 1 It is possible to move forward or backward. , generated by the fluid medium Hydraulic pressure It includes a blocking mechanism 4 that is arranged to intermittently switch between a blocked / open state between the pipe body 1 and the detection mechanism 3 by its action.

[0022] In this invention, external Hydraulic pressure The system passes the fluid medium through the pipe 1, so the fluid medium is passed through the detection mechanism 3 at a constant pressure. By utilizing the intermittent contact between the detection end of the detection mechanism 3 and the fluid medium, the fluid medium Hydraulic pressure Acquire information. Then, slide it in relation to pipe body 1. Determination to proceed A blocking mechanism 4 is provided, which intermittently controls the communication or blockage state between the pipe body 1 and the detection mechanism 3, thereby achieving intermittent contact between the detection end of the detection mechanism 3 and the fluid medium, and for a long period of time Hydraulic pressure This reduces fatigue loss to the detection mechanism 3 due to impact and improves the detection accuracy against cavitation.

[0023] In this technical solution, the blocking mechanism 4 uses a common type such as an electric valve, and by controlling the intermittent opening and closing of the electric valve using a timing control device such as a timer, an intermittent communication state between the pipe body 1 and the detection mechanism 3 can be achieved. Furthermore, the detection mechanism 3 uses, for example, a pressure detection method, a displacement detection method, etc. Hydraulic pressure It is preferable, but not limited to, that a signal is acquired. When the fluid medium passes through the detection mechanism 3 and comes into contact with the detection end, the detection end detects the pressure change, displaces, and generates a signal, and both Hydraulic pressure The signal can be acquired to determine the occurrence of cavitation.

[0024] moreover, Located downstream of the blocking mechanism 4 in the direction of fluid medium transfer A control mechanism 2 is further included, and a control section communicating with the pipe 1 is formed within the control mechanism 2. Here, pipe 1 transports the fluid medium within the control section. Hydraulic pressure When it is formed, Hydraulic pressure The closure mechanism 4 is positioned to move in the first direction to close the pipe body 1. Hydraulic pressure It works in cooperation with the control end of the control mechanism 2 to contact the detection end, The blocking mechanism 4 blocks the pipe 1, and within the control section Hydraulic pressure decreases Then, the occlusion mechanism 4 moves in the second direction opposite to the first direction, and the pipe body 1 Of these, the portion upstream of the blocking mechanism 4 in the direction of fluid medium transfer Connects the control section to the control section. Let ru.

[0025] A control mechanism 2 is provided between the pipe 1 and the detection mechanism 3, and a control section is formed within the control mechanism 2, and a fluid medium is contained within the control section, and as the pipe 1 and the control section communicate, the fluid medium within the control section Hydraulic pressure A formation is created. Hydraulic pressure When a sufficient force is generated to move the occlusion mechanism 4 in the first direction, the occlusion mechanism 4 moves in the first direction and can occlude the pipe 1. After occluding the pipe 1, the control section loses the pressure that would otherwise allow the fluid medium to pass through the pipe 1. The hydraulic pressure decreases. , due to the movement of the occlusion mechanism 4 in the second direction, the pipe body 1 Of these, the portion upstream of the blocking mechanism 4 in the direction of fluid medium transfer The control section is reconnected. After continuously passing the fluid medium through pipe 1, intermittent containment is completed by repeating the fluid medium in the control section. Hydraulic pressure Forming, Hydraulic pressure Under the control of the control mechanism 2, it makes contact with the detection end and detects the fluid medium.

[0026] Also, Hydraulic pressure When the fluid is contained to a certain extent, that is, when the generated force is constant, the blocking mechanism 4 moves in the first direction due to the influence of the applied force and blocks the pipe 1, thereby controlling the amount of fluid medium contained within the control section. Hydraulic pressure It can be understood that the relative stability of the results obtained from detection is effectively ensured, and the accuracy of cavitation detection in fluid media is effectively improved.

[0027] Furthermore, the control mechanism 2 is A first cylinder 21, with one end of its internal cavity communicating with the pipe body 1, It is slidably fitted inside the first cylinder 21, and the control end is Hydraulic pressure A control element extends from the first cylinder 21 along the other end away from the pipe body 1 and contacts the detection end, Each includes a connecting pipe 23 that communicates with the first cylinder 21 and the closure mechanism 4, and the internal cavity of the connecting pipe 23 is Hydraulic pressure This creates an action force acting in the same direction as the first direction, which acts on the occlusion mechanism 4.

[0028] A control element slidably fitted within the first cylinder 21 is used to communicate with the pipe body 1 via the first cylinder 21, and when the pipe body 1 transfers the fluid medium, the fluid medium is passed through the first cylinder 21, forming Hydraulic pressure Using this, the control end of the control element cooperates to extend from the first cylinder 21 and contact the detection end. Hydraulic pressure To enable signal acquisition. And, Hydraulic pressure When it acts, the fluid medium passes through the connecting pipe 23, and the weight of the liquid medium inside the connecting pipe 23 and Hydraulic pressure Under its influence, a force acting in the same direction as the first direction is generated and acts on the occlusion mechanism 4, causing the occlusion mechanism 4 to move in the first direction and occlude the pipe 1.

[0029] Furthermore, the control elements are, A first slider 22 is slidably fitted inside the first cylinder 21, has a seal ring 26 fitted onto it, the seal ring 26 slides in contact with the inner wall of the first cylinder 21, and has a column projection 25 integrally molded on its upper part, the column projection 25 extending from the first cylinder 21 and contacting the detection end, The assembly includes a first spring 24 wound around the column protrusion 25, with both ends of the first spring 24 fixed to the first slider 22 and the inner wall surface of the first cylinder 21, respectively.

[0030] The first slider 22 is slidably placed inside the first cylinder 21, and a seal ring 26 that contacts the inner wall of the first cylinder 21 is fitted onto the first slider 22, thereby sealing the communication end between the first cylinder 21 and the pipe body 1, and generating fluids generated by the fluid medium. Hydraulic pressure By using this, the first slider 22 is pushed, causing the column protrusion 25 to slide along the first cylinder 21 and extend, bringing it into contact with the detection end. Hydraulic pressure The signal is acquired. And, When the hydraulic pressure decreases The first spring 24 resets the first slider 22, maintaining a constant volume in the seal chamber formed within the first cylinder 21. Hydraulic pressure It makes the occurrence of [the disease] relatively stable.

[0031] Furthermore, the blocking mechanism 4 is A second cylinder 41 is provided at the tip of the first cylinder 21 and communicates with the pipe body 1 and the connecting pipe 23, respectively. The second slider 42 is slidably fitted into the second cylinder 41, with a piston structure 44 integrally molded on the side closer to the connecting pipe 23, and when an acting force in the same direction as the first direction is formed inside the connecting pipe 23, the second slider 42 moves in the first direction through the cooperation of the connecting pipe 23 and the piston structure 44, thereby closing the pipe body 1. The assembly includes a second spring 43 filled between the piston structure 44 and the connecting pipe 23, with both ends of the second spring 43 fixed to the piston mechanism and the inner wall of the second cylinder 41, respectively.

[0032] By connecting one end of the second cylinder 41 to the pipe 1, positioning the second cylinder 41 in a direction that allows the fluid medium to pass through the first cylinder 21, and connecting the other end of the second cylinder 41 to the first cylinder 21 via the connecting pipe 23, the fluid medium is contained within the first cylinder 21. Hydraulic pressure As it is formed, the fluid medium is passed through the connecting pipe 23, and gravity and Hydraulic pressure The force accumulates. When the applied force exceeds the support strength of the second spring 43, the applied force drives the piston mechanism 44 to move the second slider 42, causing the second slider 42 to extend from the second cylinder 41 and close the pipe 1. The first cylinder 21 is through which the fluid medium is continuously passed. Hydraulic pressure Lost, within the control section Hydraulic pressure decreases Then, due to the reset action of the second spring 43, the second slider 42 is lifted and the tube body 1 Of these, the portion upstream of the blocking mechanism 4 in the direction of fluid medium transfer The first cylinder 21 is reconnected to achieve an intermittent switching state.

[0033] Furthermore, the detection mechanism 3 is A third cylinder 31 is provided on the side closer to the control element and has a resistance strain gauge 33 inside, The third cylinder 31 includes a third slider 32 that is provided on the third cylinder 31 and contacts the resistance strain gauge 33, with one end of the third slider 32 extending from the third cylinder 31 and contacting the control end.

[0034] The fluid medium contained within the first cylinder 21 Hydraulic pressure The effect occurs, Hydraulic pressure This presses the first slider 22, driving the column projection 25 to extend from the first cylinder 21 and bring it into contact with the third slider 32. As the third slider 32 slides along the third cylinder 31 and comes into contact with the resistance strain gauge 33, the projection of the resistance strain gauge 33 is driven, and thereafter, Hydraulic pressure After it disappears, the resistance strain gauge 33 is reset. During this process, the resistance strain gauge 33 Hydraulic pressure It converts the pressure signal transmitted by into an electrical signal, Hydraulic pressure This enables intermittent detection of cavitation.

[0035] Furthermore, it can be understood that the resistance strain gauge 33 can be selectively replaced with a general displacement sensor within the third cylinder 31, and by detecting the sliding distance after the third slider 32 contacts the column protrusion 25, a signal generated by cavitation of the fluid medium can be similarly acquired, thereby achieving intermittent detection.

[0036] moreover, The system includes an outer cylinder 5, an outer cylinder upper cover 6 and an outer cylinder lower cover 7 which are detachably connected to the outer cylinder 5, the third cylinder 31 is fixed to the outer cylinder 5 by the outer cylinder upper cover 6 / outer cylinder lower cover 7, and the tubular body 1 is drilled inside the outer cylinder 5 and fixed to the outer cylinder 5.

[0037] Furthermore, the first cylinder 21, the second cylinder 41, and the third cylinder 31 all have a detachable connecting structure.

[0038] In this technical solution, the outer cylinder 5 is configured with two internal cavities of different sizes, and the third cylinder 31 is enclosed in the smaller internal cavity. Screw connections to the outer cylinder 5 are achieved by multiple bolts around the outer cylinder upper cover 6. The third cylinder 31 and the outer cylinder 5 are fixed together, and the third cylinder 31 is not connected to the first cylinder 21. By drilling a pipe body 1 in the larger internal cavity, the stability of the connection between the pipe body 1 and the outer cylinder 5 is ensured by a stopper card integrally molded to the pipe body 1. The first cylinder 21 and the second cylinder 41 are each connected and fixed to the pipe body 1 by three-way pipes. Furthermore, the first cylinder 21, the second cylinder 41, and the third cylinder 31 all have an upper and lower divided structure, and by achieving detachable connections via bolts, structural airtightness is protected, while at the same time facilitating the removal and maintenance of the detection device during actual use, further improving the effectiveness of cavitation detection of fluid media.

[0039] Pure water based on density Hydraulic pressure The system's cavitation detection method is based on the density of pure water as described above. Hydraulic pressure Based on the system's cavitation detection device, The steps include connecting pipe 1 to transfer the fluid medium and passing the fluid medium through the control section, formed within the control section Hydraulic pressure The steps include using to contact the first slider 22 and the second slider 42, respectively, The first slider 22 is brought into contact with the third slider 32, and the detection mechanism 3 Hydraulic pressure Steps to acquire a signal, Hydraulic pressure This drives the second slider 42 to close the pipe 1, within the control section Lower the hydraulic pressure The steps, In response to the decrease in hydraulic pressure within the control section The second spring 43 resets the second slider 42. , the portion of the pipe 1 upstream of the occlusion mechanism 4 in the direction of fluid medium transfer Connect the control section to the control section and supply the fluid medium to the control section. again Passing steps Pu and , Some obtained Hydraulic pressureThe process includes the step of taking the value m of the signal as the average of the signal peak values ​​within a unit time, where the minimum value of the signal peak value is n, and determining that cavitation is occurring when n < 0.98m, and assuming that it is not occurring otherwise.

[0040] After the fluid medium undergoes cavitation within the pipe 1, the density of the fluid medium changes. Therefore, after passing through the first cylinder 21, the fluid medium's flow velocity and the specifications of the first cylinder 21 and the first slider 22 remain constant, causing the density of the fluid medium to change and form in the first slider 22. Hydraulic pressure The strength of the action changes. Because the force applied to the first slider 22 and the third slider 32 is different due to the different magnitudes of the applied force, the corresponding electrical signals transmitted from the resistance strain gauge 33 are also different, and then the second slider 42 Hydraulic pressure By applying pressure and intermittently closing the pipe 1, the fluid medium is utilized Hydraulic pressure It achieves adaptive adjustment. Hydraulic pressure The signal is intermittently detected by the resistance strain gauge 33, and the unit time is set to 10 seconds as an example. The peak value of the resistance strain gauge 33 detected within 10 seconds is, i.e. Hydraulic pressure By recording the force applied to press the first slider 22 and comparing the difference between the average peak value and the minimum peak value, accurate detection of cavitation in the fluid medium is achieved.

[0041] In the description of this invention, the orientations or positional relationships indicated by terms such as "vertical," "horizontal," "up," "down," "front," "back," "left," "right," "perpendicular," "horizontal," "top," "bottom," "inside," and "outside" are based on the orientations or positional relationships shown in the drawings and are intended solely to facilitate the description of this invention. They are not intended to indicate or imply that the mentioned devices or elements must have a particular orientation, be configured in a particular orientation, or operate in a particular orientation, and therefore should not be construed as limitations of this invention.

[0042] The embodiments described above merely illustrate preferred aspects of the present invention and do not limit the scope of the invention. Various modifications and improvements made by those skilled in the art to address the technical problems of the present invention, without departing from the spirit of the design of the present invention, should be included within the scope of protection defined by the claims of the present invention. [Explanation of symbols]

[0043] 1. Body 2. Control mechanism 21 First Cylinder 22 First Slider 23 Communication pipe 24 1st Spring 25 Column protrusions 26 sealing rings 3. Detection mechanism 31 Third Cylinder 32 Third Slider 33 Resistance Strain Gauge 4 Closure mechanism 41. Second Cylinder 42. Second slider 43. Second Spring 44 Piston structure 5. Outer cylinder 6. Outer cylinder upper cover 7. Outer cylinder lower cover

Claims

1. A cavitation detection device for a density-based pure water hydraulic pressure system, A pipe (1) for transferring a fluid medium, A detection mechanism (3) is positioned on the tube (1) and its detection end is arranged to intermittently contact the fluid medium to acquire a cavitation signal of the fluid medium, The system includes a closure mechanism (4) which is slidable in a first direction toward entering the pipe (1) and in a second direction toward exiting the pipe (1), and is biased in the second direction, and is arranged to intermittently switch the closed / open state of the pipe (1) by the hydraulic action generated by the fluid medium, The system further includes a control mechanism (2) positioned downstream of the blocking mechanism (4) in the direction of fluid transport, and a control section communicating with the pipe (1) is formed within the control mechanism (2). Here, when the pipe (1) transports the fluid medium and the hydraulic pressure is formed within the control section, the hydraulic pressure is positioned to move the occlusion mechanism (4) in the first direction to occlude the pipe (1), and the hydraulic pressure cooperates with the control end of the control mechanism (2) to contact the detection end. A density-based cavitation detection device for a pure water hydraulic system, characterized in that when the blocking mechanism (4) blocks the pipe (1) and the hydraulic pressure in the control section decreases, the blocking mechanism (4) moves in a second direction opposite to the first direction, thereby connecting the portion of the pipe (1) upstream of the blocking mechanism (4) in the transport direction with the control section.

2. The control mechanism (2) is A first cylinder (21) whose internal cavity is connected to the pipe (1), A control element is slidably fitted within the first cylinder (21), with a control end extending from the first cylinder (21) along the other end that is separated from the pipe body (1) by the hydraulic pressure, and contacting the detection end. A cavitation detection device for a density-based pure water hydraulic system according to claim 1, comprising a connecting pipe (23) communicating with the first cylinder (21) and the blocking mechanism (4), wherein a force acting in the same direction as the first direction is formed in the internal cavity of the connecting pipe (23) by the hydraulic pressure and acts on the blocking mechanism (4).

3. The control element is A first slider (22) is slidably fitted inside the first cylinder (21), has a seal ring (26) fitted to it, the seal ring (26) slides in contact with the inner wall of the first cylinder (21), has a column projection (25) integrally molded on its upper part, and the column projection (25) extends from the first cylinder (21) and contacts the detection end, A cavitation detection device for a density-based pure water hydraulic system according to claim 2, comprising a first spring (24) wound around the column protrusion (25), wherein both ends of the first spring (24) are fixed to the first slider (22) and the inner wall surface of the first cylinder (21), respectively.

4. The aforementioned blocking mechanism (4) is A second cylinder (41) is provided at the tip of the first cylinder (21) and communicates with the pipe body (1) and the connecting pipe (23), respectively. A second slider (42) is slidably fitted to the second cylinder (41), with a piston structure (44) integrally molded on the side closer to the connecting pipe (23), and when an acting force in the same direction as the first direction is formed within the connecting pipe (23), the second slider (42) moves in the first direction through the cooperation of the connecting pipe (23) and the piston structure (44) to close the pipe body (1), A cavitation detection device for a density-based pure water hydraulic system according to claim 2, comprising a second spring (43) filled between the piston structure (44) and the connecting pipe (23), wherein both ends of the second spring (43) are fixed to the piston mechanism and the inner wall of the second cylinder (41), respectively.

5. The aforementioned detection mechanism is A third cylinder (31) is provided on the side closer to the control element and has a resistance strain gauge (33) inside, A cavitation detection device for a density-based pure water hydraulic system according to claim 4, comprising a third slider (32) provided on the third cylinder (31) and in contact with the resistance strain gauge (33), wherein one end of the third slider (32) extends from the third cylinder (31) and in contact with the control end.

6. Furthermore, the cavitation detection device for a density-based pure water hydraulic pressure system according to claim 5, further comprising an outer cylinder (5), an outer cylinder upper cover (6) and an outer cylinder lower cover (7) detachably connected to the outer cylinder (5), wherein the third cylinder (31) is fixed to the outer cylinder (5) by the outer cylinder upper cover (6) / outer cylinder lower cover (7), and the tubular body (1) is drilled inside the outer cylinder (5) and fixed to the outer cylinder (5).

7. The cavitation detection device for a density-based pure water hydraulic pressure system according to claim 5, characterized in that the first cylinder (21), the second cylinder (41), and the third cylinder (31) all have a detachable connecting structure.

8. A method for detecting cavitation in a density-based pure water hydraulic pressure system, based on a cavitation detection device for a density-based pure water hydraulic pressure system according to any one of claims 1 to 5, The steps include connecting the pipe (1) to transfer the fluid medium and passing the fluid medium through the control section, The steps include using the hydraulic pressure formed within the control section to act on the first slider (22) and the second slider (42), respectively, The first slider (22) is brought into contact with the third slider (32), and a hydraulic pressure signal is obtained by the detection mechanism (3). The steps include driving the second slider (42) to close the pipe (1) and reduce the hydraulic pressure in the control section, In response to a decrease in the hydraulic pressure within the control section, the second spring (43) resets the second slider (42), thereby connecting the portion of the pipe (1) upstream of the blocking mechanism (4) in the transfer direction to the control section, and allowing the fluid medium to pass through the control section again. A density-based method for detecting cavitation in a pure water hydraulic system, comprising the steps of taking the value m of the average of the signal peak values ​​within a unit time from several acquired hydraulic pressure signals, determining that cavitation is occurring when the minimum value of the signal peak is n, and considering that it is not occurring otherwise.

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