A magnetic fluid seal detection structure and detection method

Abstract

The application discloses a kind of magnetic fluid seal detection structures, including rotating main shaft and the left pole shoe and right pole shoe of being sleeved on rotating main shaft, left pole shoe, right pole shoe with rotating main shaft between all have annular gap, annular gap is provided with magnetic fluid, left pole shoe and right pole shoe between being provided with the sealing cavity with certain pressure;Located in the outside of one side magnetic fluid installs the sensor for detecting the position of magnetic fluid;The magnetic pole of left pole shoe and right pole shoe is different, when the failure of another side magnetic fluid appears, magnetic fluid on the same side of sensor is away from sensor, sensor detects the position change of magnetic fluid and sends signal after.The problems that existing device and method cannot effectively detect the validity of online used magnetic fluid seal are solved.

Description

Technical Field

[0001] This invention relates to the field of magnetic fluid seal testing technology, and in particular to a magnetic fluid seal testing structure and testing method. Background Technology

[0002] Magnetofluidic seals utilize a magnetic field to firmly bind a magnetic fluid within a sealing gap, forming one or more stable liquid O-rings. The magnetic force balances the external pressure difference, achieving a zero-leakage, contactless dynamic seal. Magnetofluidic seals are widely used in hydroelectric equipment. However, currently, the operational status of magnetofluidic seals during online use cannot be detected, posing a potential safety hazard to production and making it impossible to predict the reliability of the sealing device. To address this issue, I have proposed a magnetofluidic seal testing structure and method.

[0003] After searching, it was found that in the existing technology, such as the magnetic fluid sealing performance testing device proposed in CN115265959A and the sealing performance testing device for magnetic fluid proposed in CN120651442A, both of them are offline magnetic fluid sealing tests and cannot perform effectiveness testing on magnetic fluid seals used online. Summary of the Invention

[0004] In view of the above-mentioned shortcomings in the prior art, the present invention provides a magnetohydrodynamic seal detection structure and detection method to solve the problem that existing devices and methods cannot detect the effectiveness of magnetohydrodynamic seals used online.

[0005] To achieve the above objectives, this application provides a magnetofluid sealing detection structure, including a rotating spindle and a left pole shoe and a right pole shoe mounted on the rotating spindle. Each pole shoe has an annular gap with the rotating spindle, and magnetofluid is disposed within the annular gap. A sealed cavity with a certain pressure is provided between the left and right pole shoes. A sensor for detecting the position of the magnetofluid is installed on the outside of one side of the magnetofluid. The left and right pole shoes have different magnetic poles. When the magnetofluid on the other side fails, the magnetofluid on the same side as the sensor moves away from the sensor. The sensor detects the change in the position of the magnetofluid and sends a signal.

[0006] A permanent magnet is disposed between the left and right pole shoes, and a sealed cavity is located between the permanent magnet and the rotating spindle.

[0007] The permanent magnet is ring-shaped.

[0008] The sealed cavity is filled with a pressurized medium.

[0009] The pressure medium may be gas or liquid.

[0010] The permanent magnet is provided with a flow channel hole, which is connected to the sealed cavity for filling the sealed cavity with a pressure medium. The flow channel hole is provided with a sealing element for sealing the flow channel hole.

[0011] It also includes a monitor, which communicates with the sensor and is used to acquire the signals output by the sensor.

[0012] The sensor has a ring structure.

[0013] The sensor is either a touch sensor or a displacement sensor.

[0014] A detection method applied to the aforementioned magnetohydrodynamic (MHD) seal detection structure, used to detect whether an online MHD seal has failed, the detection method comprising: When there is a certain pressure in the sealed cavity, the magnetofluid located in the inner ring of the left and right pole shoes deforms outward to form a pressurized magnetofluid shape, and the sensor detects the change in the position of the magnetofluid on one side. When the magnetofluid on the other side fails, the sealed cavity loses pressure, and the magnetofluid located in the inner ring of the left and right pole shoes deforms inward, forming a pressureless magnetofluid state. The sensor detects the change in the position of the magnetofluid and sends a signal.

[0015] Compared with the prior art, the above-conceptual technical solution conceived in this application has the following beneficial effects: The sensor of this invention is installed on the outside of the magnetofluid under the right pole shoe. The left and right pole shoes have different magnetic poles. A closed magnetic field is formed by the left pole shoe, the magnetofluid, the main shaft, and the right pole shoe, fixing the magnetofluid in the gap and achieving a sealing effect. When there is no pressure in the sealed cavity, the magnetofluid in the inner rings of the left and right pole shoes forms a pressureless magnetofluid state. A pressurized sealed cavity is provided between the left and right pole shoes. Its functions are at least twofold: First, the magnetofluid pressure under the right pole shoe is transmitted to the left pole shoe through the sealed cavity, forming a pressurized magnetofluid state, thus improving the pressure resistance of the magnetofluid under the left pole shoe. Second, the magnetofluid under the right pole shoe protrudes outward and can be detected by the sensor. When the magnetofluid under the left pole shoe fails, the sealed cavity loses pressure, and the magnetofluid located in the inner rings of both the left and right pole shoes deforms inward, transforming into an unpressurized magnetofluid state. The sensor detects this change in the magnetofluid's position and sends a signal, indicating that the magnetofluid sealing device has a problem or that the first-stage seal has failed, thereby enabling the effectiveness detection of the magnetofluid seal used online. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the testing mechanism of the present invention.

[0018] Figure 2 This is a schematic diagram showing the connection between the sensor and the monitor of the present invention.

[0019] Figure 3 This is a schematic diagram showing the pressurized and unpressurized magnetic fluid states during the implementation of this invention.

[0020] Figure label: Rotary spindle 1, sealing end cap 2, left pole shoe 3, right pole shoe 4, sealing element 5, flow channel hole 6, sealing cavity 7, magnetofluid 8, sensor 9; monitor 10, signal cable 11, air pressure 12, magnetic lines of force 13, unpressurized magnetofluid form 14, pressurized magnetofluid form 15, permanent magnet 16. Detailed Implementation

[0021] To more clearly illustrate the purpose, technical solution, and beneficial effects of this application, a further detailed description of this application is provided below in conjunction with illustrations and specific embodiments. It should be specifically noted that the specific embodiments described below are only for illustrating the technical content of this application and do not constitute a limitation on the scope of protection of this application.

[0022] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0023] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection via an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Example 1: See Figures 1-3 This invention provides a magnetohydrodynamic (MHD) sealing detection structure, including a rotating spindle 1 and a left pole shoe 3 and a right pole shoe 4 mounted on the rotating spindle 1. Both the left pole shoe 3 and the right pole shoe 4 have annular gaps with the rotating spindle 1, and a magnetohydrodynamic fluid 8 is disposed within these annular gaps. A sealed cavity 7 with a certain pressure is disposed between the left pole shoe 3 and the right pole shoe 4. A sensor 9 for detecting the position of the magnetohydrodynamic fluid 8 is installed on the outside of one side of the magnetohydrodynamic fluid 8. The left pole shoe 3 and the right pole shoe 4 have different magnetic poles. When the magnetohydrodynamic fluid 8 on the other side fails, the magnetohydrodynamic fluid 8 on the same side as the sensor 9 moves away from the sensor 9. The sensor 9 detects the change in the position of the magnetohydrodynamic fluid 8 and sends a signal.

[0025] See Figure 1 and Figure 3 A ring-shaped left pole shoe 3 is fitted on the left side of the rotating spindle 1, and a ring-shaped right pole shoe 4 is fitted on the right side. A sealing end cap 2 is installed on the side of the left pole shoe 3 away from the right pole shoe 4. The sealed medium is the fluid between the rotating spindle 1 and the sealing end cap 2. The sensor 9 is installed on the outside of the magnetofluid 8 under the right pole shoe 4. The left pole shoe 3 and the right pole shoe 4 have different magnetic poles. A closed magnetic field is formed by the left pole shoe 3, the magnetofluid 8, the spindle 1, and the right pole shoe 4, fixing the magnetofluid 8 in the gap and achieving a sealing effect. When there is no pressure in the sealed cavity 7, see [reference needed]. Figure 3 The magnetofluid 8 within the inner rings of the left pole shoe 3 and the right pole shoe 4 forms a pressureless magnetofluid configuration 14, such as... Figure 3 As shown by the solid dot. Because a sealed cavity 7 with a certain pressure is provided between the left pole shoe 3 and the right pole shoe 4, its function is at least twofold: First, the pressure of the magnetofluid 8 under the right pole shoe 4 is transmitted to the left pole shoe 8 through the pressure of the sealed cavity 7, forming a pressurized magnetofluid configuration 15, such as... Figure 3As shown in the hollow point, the pressure resistance of the magnetic fluid 8 under the left pole shoe 3 is improved; secondly, the magnetic fluid 8 under the right pole shoe 4 protrudes outward and can be detected by the sensor 9. When the magnetic fluid 8 under the left pole shoe 3 fails, the sealed cavity 7 loses pressure, and the magnetic fluid 8 located in the inner ring of the left pole shoe 3 and the right pole shoe 4 deforms inward and transforms into the unpressurized magnetic fluid state 14. After the sensor 9 detects the change in the position of the magnetic fluid 8, it sends a signal indicating that the magnetic fluid sealing device has a problem or the first-level seal has failed, thereby realizing the effectiveness detection of the magnetic fluid seal used online.

[0026] Furthermore, a permanent magnet 16 is disposed between the left pole shoe 3 and the right pole shoe 4, and a sealed cavity 7 is located between the permanent magnet 16 and the rotating main shaft 1. Under the action of the magnetic field of the permanent magnet 16, the magnetic poles of the left pole shoe 3 and the right pole shoe 4 are different, thereby forming a closed magnetic field through the left pole shoe 3, the magnetic fluid 8, the main shaft 1, and the right pole shoe 4, fixing the magnetic fluid 8 in the gap and achieving a sealing effect. Figure 1 The image shows a secondary seal, which means there are two magnetohydrodynamic seals.

[0027] In this embodiment, the permanent magnet 16 is ring-shaped.

[0028] In this embodiment, the sealed cavity 7 is filled with a pressurized medium. Further, the pressurized medium includes gas or liquid.

[0029] Further, see Figure 1 The permanent magnet 16 is provided with a flow channel hole 6, which communicates with the sealed cavity 7 and is used to fill the sealed cavity 7 with a pressure medium. The flow channel hole 6 is provided with a sealing element 5 for sealing the flow channel hole 6. The sealing element 5 can be a valve or a sealing screw.

[0030] Example 2: Based on Example 1, see Figure 2 It also includes a monitor 10, which is communicatively connected to the sensor 9 and is used to acquire the signals output by the sensor 9. The monitor 10 can communicate with the sensor 9 wirelessly or electrically via a signal cable 11. The monitor 10 can be a PLC. In use, the monitor 10 is electrically connected to a display screen to display the detection status and / or data.

[0031] In one of the designs, sensor 9 has a ring structure.

[0032] Specifically, sensor 9 is a touch sensor or a displacement sensor. When a touch sensor is used, in the pressurized magnetic fluid state 15, the magnetic fluid 8 under the right pole shoe 4 protrudes outward and contacts the touch sensor. When the magnetic fluid 8 is in the unpressurized magnetic fluid state 14, the magnetic fluid 8 under the right pole shoe 4 separates from the touch sensor, and sensor 9 sends a signal.

[0033] When a displacement sensor is used, multiple ultrasonic or infrared ranging sensors are installed on the annular base plate to detect the position data of the magnetic fluid 8 under the right pole shoe 4 in real time. When the position data is greater than the threshold, it can be determined that the magnetic fluid seal has a problem or the first-stage seal has failed.

[0034] Example 3: Based on Example 1 or Example 2, a detection method for a magnetohydrodynamic (MHD) seal detection structure is provided to detect whether an online MHD seal has failed. The detection method includes: When there is a certain pressure in the sealed cavity 7, the magnetofluid 8 located in the inner ring of the left pole shoe 3 and the right pole shoe 4 both deform outward to form a pressurized magnetofluid shape 15, and the sensor 9 detects the position change of the magnetofluid 8 on one side. When the magnetofluid 8 on the other side fails, the sealed cavity 7 loses pressure, and the magnetofluid 8 located in the inner ring of the left pole shoe 3 and the right pole shoe 4 deforms inward, forming a pressureless magnetofluid state 14. The sensor 9 detects the position change of the magnetofluid 8 and sends a signal.

[0035] See Figure 3 Specifically, under the action of magnetic field lines 13, the magnetic fluid seal forms a magnetic sealing surface, creating a pressureless magnetic fluid state 14, as shown by the solid dot in the figure. After high-pressure gas is filled into the sealed cavity 7, under the action of magnetic field force and gas pressure 12, a pressurized magnetic fluid state 15 is formed, as shown by the hollow dot in the figure. The touch sensor is in contact with the magnetic fluid 8 on the right pole shoe 4 side. When the pressure is lost, the touch sensor separates from the magnetic fluid 8 on the right pole shoe 4 side, and the touch sensor sends a signal, which is fed back to the monitor 10 through the signal cable 11, informing the production personnel that the magnetic fluid sealing device is in an unstable state.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A magnetohydrodynamic sealing detection structure, characterized in that: It includes a rotating spindle (1) and a left pole shoe (3) and a right pole shoe (4) mounted on the rotating spindle (1). There is an annular gap between the left pole shoe (3), the right pole shoe (4) and the rotating spindle (1). A magnetic fluid (8) is provided in the annular gap. A sealed cavity (7) with a certain pressure is provided between the left pole shoe (3) and the right pole shoe (4). A sensor (9) for detecting the position of the magnetic fluid (8) is installed on the outside of the magnetic fluid (8) on one side. The magnetic poles of the left pole shoe (3) and the right pole shoe (4) are different. When the magnetic fluid (8) on the other side fails, the magnetic fluid (8) on the same side as the sensor (9) moves away from the sensor (9). The sensor (9) sends a signal after detecting the position change of the magnetic fluid (8).

2. The magnetohydrodynamic sealing detection structure according to claim 1, characterized in that: A permanent magnet (16) is provided between the left pole shoe (3) and the right pole shoe (4), and a sealed cavity (7) is located between the permanent magnet (16) and the rotating main shaft (1).

3. The magnetohydrodynamic sealing detection structure according to claim 2, characterized in that: The permanent magnet (16) is ring-shaped.

4. A magnetohydrodynamic sealing detection structure according to claim 1, 2, or 3, characterized in that: The sealed cavity (7) is filled with a pressurized medium.

5. The magnetohydrodynamic sealing detection structure according to claim 4, characterized in that: The pressure medium may be gas or liquid.

6. The magnetohydrodynamic sealing detection structure according to claim 2, characterized in that: The permanent magnet (16) is provided with a flow channel hole (6), which is connected to the sealed cavity (7) for filling the sealed cavity (7) with a pressure medium. The flow channel hole (6) is provided with a sealing member (5) for sealing the flow channel hole (6).

7. The magnetohydrodynamic sealing detection structure according to claim 1, characterized in that: It also includes a monitor (10), which is connected in communication with the sensor (9). The monitor (10) is used to acquire the signal output by the sensor (9).

8. The magnetohydrodynamic sealing detection structure according to claim 1, characterized in that: The sensor (9) has a ring structure.

9. A magnetohydrodynamic sealing detection structure according to claim 1 or 8, characterized in that: The sensor (9) is a touch sensor or a displacement sensor.

10. A detection method applied to the magnetohydrodynamic sealing detection structure of claim 1, characterized in that, The detection methods for determining whether an online magnetohydrodynamic seal has failed include: When there is a certain pressure in the sealed cavity (7), the magnetofluid (8) located in the inner ring of the left pole shoe (3) and the right pole shoe (4) deforms outward to form a pressurized magnetofluid morphology (15), and the sensor (9) detects the position change of the magnetofluid (8) on one side. When the magnetofluid (8) on the other side fails, the sealed cavity (7) loses pressure, and the magnetofluid (8) located in the inner ring of the left pole shoe (3) and the right pole shoe (4) deforms inward to form a pressureless magnetofluid state (14). The sensor (9) detects the position change of the magnetofluid (8) and sends a signal.

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