A test system for monitoring seal surface wear based on changes in conductive coating resistance

Abstract

The present invention discloses a test system for monitoring seal surface wear based on changes in conductive coating resistance, characterized in that it includes a mechanical end face seal, a resistance test module, and a wire output module; the resistance test module includes multiple resistance test instruments and connection nodes, the connection nodes are located at both ends of the resistance test instrument, and the connection nodes correspond one-to-one with the test nodes; the wire output module includes lead-out wires, lead-in wires, and terminal blocks, the lead-out wires are connected to the test nodes, the lead-in wires are connected to the connection nodes, and the lead-out wires and lead-in wires are respectively connected to the terminal blocks. The present invention associates the wear state of the mechanical seal surface with the change in its resistance value, and through the readings of an external array resistance test instrument and a pre-acquired conductive coating wear-resistance correlation model, it realizes real-time online and in-situ intelligent monitoring of the wear state of the built-in mechanical seal end face in service, thereby predicting the failure of the sealing system and improving the operational reliability of the sealing system.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent monitoring systems for sealing operation status, and in particular to a testing system for monitoring sealing surface wear based on changes in conductive coating resistance. Background Art

[0002] Wear of the end face of a mechanical seal is an irreversible process. Excessive end face wear will cause significant changes in the macro-profile and micro-morphology of the seal end face, forming a direct leakage channel on the sealing surface, affecting the normal performance of the mechanical seal and shortening the service life of the seal. In order to improve the wear resistance of the mechanical seal end face and reduce the friction coefficient during contact friction of the seal end face, a wear-resistant and low-friction coating is often applied to the end face of the sealing ring, such as DLC coating, diamond coating, etc., and the sealing ring substrate is generally made of silicon carbide, an insulating material. However, mechanical seals are usually installed inside the equipment, and their wear status cannot be monitored in real time and accurately, which makes it very difficult to monitor and evaluate the end face wear status of in-service mechanical seals on-site. At present, the surface wear of mechanical seals is generally tested by testing the seal end face morphology before and after the experiment to obtain the volume wear and linear wear of the seal end face, or by weighing the seal ring before and after the experiment to obtain the mass wear. This method requires multiple removals of the mechanical seal to measure wear and accumulate cumulative wear. This alters the friction and fit of the seal friction pair, causing significant deviations between the end-face wear test and the actual end-face wear state during continuous operation. Furthermore, the experimental work is labor-intensive and inefficient. Chinese patent CN113465845A proposes a real-time detection method for dynamic seal wear failure. This method, which incorporates an insulating layer around the conductive seal, automatically issues a seal wear failure alarm when the insulating layer is damaged. However, this method can only detect seal wear failure and cannot accurately monitor end-face wear in real time. Summary of the Invention

[0003] In order to improve the problems of frequent disassembly of mechanical seals, large measurement errors and inability to achieve online real-time monitoring in existing mechanical seal surface wear tests, the present invention provides a real-time monitoring system for the wear status of the end face of a built-in mechanical seal in service through the readings of an external array resistance test meter and a pre-acquired conductive coating "wear-resistance" correlation model.

[0004] The technical solutions of the present invention are as follows:

[0005] A test system for monitoring sealing surface wear based on changes in conductive coating resistance, characterized in that it includes a mechanical end face seal, a resistance test module and a wire output module; the mechanical end face seal includes a dynamic ring, a static ring and a sealing cavity, the dynamic ring and the static ring are both installed in the sealing cavity, the static ring includes an insulating sealing ring base and a conductive coating, the conductive coating is evenly coated on the end face of the insulating sealing ring base, and a plurality of circumferentially uniformly distributed test nodes are respectively provided on the outer diameter edge and the inner diameter edge of the conductive coating; the resistance test module includes a plurality of resistance test instruments and connection nodes, the connection nodes are located at both ends of the resistance test instrument, and the connection nodes correspond one-to-one to the test nodes; the wire output module includes a lead-out wire, an lead-in wire and a terminal block, the lead-out wire is connected to the test node, the lead-in wire is connected to the connection node, and the lead-out wire and the lead-in wire are respectively connected to the terminal block.

[0006] Furthermore, the outer diameter edge of the conductive coating is provided with a plurality of first test nodes evenly distributed along the circumferential direction, and the inner diameter edge of the conductive coating is provided with a plurality of second test nodes evenly distributed along the circumferential direction. The number of the second test nodes is the same as the number of the first test nodes and is staggered along the circumferential direction.

[0007] Furthermore, the lead wire includes a first lead wire, a second lead wire and a wiring joint, the wiring joint is fixed on the sealed cavity, one end of the first lead wire is connected to the first test node, and the other end is connected to the wiring joint.

[0008] Furthermore, an annular groove is provided on the outer peripheral surface of the insulating sealing ring base, and the first lead-out wire is fixed in the annular groove by a tightening ring to avoid contact with the dynamic ring. The transition wire between the static ring and the wiring joint of the first lead-out wire is a freely retractable spiral.

[0009] Furthermore, a wire lead-out hole is provided on the sealed cavity, one end of the second lead-out wire is connected to the second test node, and the other end of the second lead-out wire passes through the wire lead-out hole to avoid contact with the rotating part.

[0010] Furthermore, the conductive coating has a resistivity of 10 -5 Ω·m to 10 7 Ω·m, the insulating sealing ring substrate has a resistivity greater than 10 7 Ω·m insulator, the lead-out wire and the lead-in wire both have a resistivity of less than 10 -5 Ω·m conductor.

[0011] Furthermore, one side surface of the conductive coating is tightly fitted with the end surface of the insulating sealing ring substrate, the other side surface of the conductive coating is a sealing surface, and the thickness of the conductive coating is 1 μm to 500 μm.

[0012] Furthermore, the dynamic ring is fixed on the shaft sleeve and rotates therewith, the static ring is floatingly installed in the sealing cavity, and a push ring, an auxiliary sealing ring and an elastic element are provided between the static ring and the sealing cavity.

[0013] Furthermore, the number of the first test nodes is no less than 3, preferably 6 to 18.

[0014] Furthermore, the resistance testing module includes a resistance testing meter, a connection node, a resistance testing box and a resistance testing cover. The resistance testing box is provided with a wire introduction hole for introducing the wire through. The resistance testing cover is located above the resistance testing box, and the resistance testing meter is embedded in the resistance testing cover.

[0015] Working principle:

[0016] When the mechanical seal is running, the conductive coating on the insulating seal ring substrate will be partially worn. The loss of conductive coating material caused by wear will cause the resistance value of the conductive coating at that location to change, while the resistance value of the area without wear remains almost unchanged. Since the insulating seal ring substrate has a resistivity greater than 10 7 Ω·m insulator, while the conductive coating has a resistivity of 10 -5 Ω·m to 10 7 Because the conductive coating is a semiconductor with a resistance between Ω·m and Ω·m, changes in the resistance of the conductive coating can be read using a resistance tester. During mechanical seal installation, test nodes are evenly and staggeredly arranged along the circumference at the edges of the inner and outer diameters of the seal ring. One end of the lead wire is connected to the test node. The other ends of the first and second lead wires are respectively led out through the wiring connector and the wire lead hole located on the seal cavity and connected to the wiring block. The other end of the wiring block is connected to the resistance test module. The test nodes on the seal ring correspond one-to-one with the connection nodes of the resistance test module. Therefore, when the surface coating of the mechanical seal wears during operation, the resistance test module can be used to read the change in resistance between two adjacent test nodes on the seal ring in real time. By analyzing the real-time change results of the external resistance tester with the "wear-resistance" correlation model of the seal ring surface coating obtained in advance, real-time on-site monitoring of the wear status of the end face of the in-service built-in mechanical seal can be achieved.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1) Correlate the wear status of the mechanical seal surface with the change in its resistance value. Through the readings of an external array resistance tester and the pre-acquired "wear-resistance" correlation model of the conductive coating, the wear status of the built-in mechanical seal end face in service can be monitored online in real time, thereby predicting the failure of the sealing system and improving the operational reliability of the sealing system.

[0019] 2) The wear-resistant coating on the end face of the sealing ring commonly used in mechanical seals is used as the wear monitoring object. The wear status of the end face can be monitored by adjusting the coating elements to make it a semiconductor without making major adjustments to the mechanical sealing ring structure. The structure is simple and the operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a sealing ring surface wear testing system according to an embodiment of the present invention;

[0021] Figure 2 1 is a schematic diagram of the sealing ring structure of an embodiment of the present invention;

[0022] Figure 3 2 is a schematic diagram of the connection structure of the resistance test module according to an embodiment of the present invention;

[0023] Figure 4 2. It is a schematic diagram of the sealing static ring connection structure according to an embodiment of the present invention;

[0024] Figure 5 1 is a schematic structural diagram of a resistance testing module according to an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of local wear on the surface of a sealing ring according to an embodiment of the present invention;

[0026] Figure 7 Schematic diagram of the full circumference wear of the sealing ring surface according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The implementation of the present invention is further described in detail with reference to the accompanying drawings.

[0028] Example:

[0029] Reference Figure 1 、 2 , 3, 4, 5. A test system for monitoring seal surface wear based on changes in conductive coating resistance includes a mechanical end face seal 1, a resistance test module 2, and a wire output module 3. The mechanical end face seal 1 includes a dynamic ring 4, a static ring 5, and a sealing cavity 6. The dynamic ring 4 and the static ring 5 form a sealing pair and are both installed in the sealing cavity 6. The dynamic ring 4 is a fixed sealing ring that rotates with the rotating shaft, and the static ring 5 is a floating sealing ring that is floatingly installed on the sealing cavity 6 and can float axially. The outer diameter side of the sealing pair is a pressure medium chamber, and the inner diameter side is a low-pressure leakage chamber.

[0030] The stationary ring 5 is composed of an insulating sealing ring base 51 and a conductive coating 52. The conductive coating 52 is evenly coated on the end surface of the insulating sealing ring base 51. The conductive coating 52 has a resistivity of 10 -5 Ω·m to 10 7Ω·m between the semiconductor, the insulating sealing ring substrate 51 is a resistivity greater than 10 7 Ω·m insulator. Multiple first test nodes 531 and second test nodes 532 are circumferentially staggered and evenly distributed on the outer and inner diameter edges of the conductive coating 52. A first lead wire 311 located within the pressure medium chamber has one end connected to the first test node 531 and the other end connected to a wiring connector 313, which is fixed to the sealed cavity 6. A second lead wire 312 located within the low-pressure leakage chamber has one end connected to the second test node 532 and the other end extending through a wire lead-out hole 61 in the sealed cavity 6. The wire lead-out hole 61 is provided to prevent the second lead wire 312 from rubbing against the rotating shaft and causing damage.

[0031] An annular groove 54 is defined on the outer circumference of the insulating sealing ring base 51. The first lead wire 311, extending from the outer diameter edge 521 of the conductive coating 52, is secured within the groove 54 by a clamping ring 55 to prevent contact with the rotating dynamic ring 4. The transition wire 314 between the first lead wire 311 and the stationary ring 5 and the terminal connector 313 is designed as a retractable spiral to facilitate assembly and disassembly of the terminal connector 313. In operation, the transition wire 314 is retracted; when the terminal connector 313 is removed, the transition wire 314 is extended.

[0032] The lead-out wire 31 and the lead-in wire 32 are connected to the terminal block 33 respectively, and the lead-out wire 31 and the lead-in wire 32 have a resistivity of less than 10 -5 The terminal block 33 is provided to facilitate the connection of the lead-out wire 31 and the lead-in wire 32, as well as the disassembly and assembly of the front mechanical end face seal 1 and the resistance test module 2.

[0033] The resistance testing module 2 includes a resistance testing meter 21, a connection node 22, a resistance testing box 23 and a resistance testing cover 24. The connection nodes 22 are located at both ends of the resistance testing meter 21. The connection nodes 22 correspond one-to-one with the test nodes 53. A wire introduction hole 231 is provided on the resistance testing box 23 for the introduction of the wire 33. The introduction wire 32 is connected to the connection node 22. The change in resistance value between adjacent test nodes on the sealed surface uniformly coated with a conductive coating can be read by the resistance testing meter.

[0034] Taking the first test node a9 located on the outer diameter edge 521 of the sealing surface as an example, its adjacent test node on the outer diameter edge 521 is a8, and its two adjacent test nodes on the inner diameter edge 522 are a2. a9, a8, and a2 are connected to the connection nodes A9, A8, and A2 in the resistance test module 2 through the wire output module 3; further, resistance test instruments R89, R29, and R28 are respectively provided between A9 and A8 and A2.

[0035] Reference Figure 6 When eccentric wear S1 occurs on the seal ring surface, the resistance of the conductive coating on the seal surface near test nodes a2, a8, and a9 will change due to material loss. The resistance meter readings between adjacent connection nodes A2, A8, and A9 corresponding to these three test nodes will also change synchronously. This means that the resistance of resistance display meters R28, R29, and R89 will increase, while the resistance of the remaining unworn areas will change minimally. Therefore, by analyzing the real-time changes in the readings of an external array resistance meter and a pre-established "wear-resistance" correlation model for the conductive coating, real-time, in-situ monitoring of the wear status of in-service built-in mechanical seal end faces can be achieved.

[0036] Reference Figure 7 When the sealing ring surface experiences full-circumferential wear S2, the resistance test meter readings between the connection nodes corresponding to adjacent test nodes will show symmetrical changes. The resistance value between adjacent first test nodes 531 on the outer diameter edge 521 will not change significantly, and the resistance value between adjacent second test nodes 532 on the inner diameter edge 522 will not change significantly either. However, the resistance value between the first test node 531 on the outer diameter edge 521 and the second test node 532 on the adjacent inner diameter edge 522 will increase significantly. Taking R89, R29, and R28 as examples, the R89 reading will not increase significantly, while both R29 and R39 will increase significantly. Therefore, by analyzing the real-time changes in the readings of the external array resistance display instrument and the pre-acquired "wear-resistance" correlation model of the conductive coating, real-time monitoring of the wear status of the in-service built-in mechanical seal end face can be achieved.

[0037] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The scope of protection of the present invention should not be regarded as limited to the specific forms described in the embodiments. The scope of protection of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A test system for monitoring seal surface wear based on changes in conductive coating resistance, characterized in that: The invention comprises a mechanical end face seal (1), a resistance test module (2) and a wire output module (3); the mechanical end face seal (1) comprises a dynamic ring (4), a static ring (5) and a sealing cavity (6); the dynamic ring (4) and the static ring (5) are both installed in the sealing cavity (6); the static ring (5) comprises an insulating sealing ring base (51) and a conductive coating (52); the conductive coating (52) is evenly coated on the end face of the insulating sealing ring base (51); a plurality of circumferentially evenly distributed test nodes are respectively provided on the outer diameter edge (521) and the inner diameter edge (522) of the conductive coating (52). (53); the resistance test module (2) includes a plurality of resistance test instruments (21) and connection nodes (22), the connection nodes (22) are located at both ends of the resistance test instrument (21), and the connection nodes (22) correspond to the test nodes (53) one by one; the wire output module (3) includes an outgoing wire (31), an incoming wire (32) and a terminal block (33), the incoming wire (31) is connected to the test node (53), the incoming wire (32) is connected to the connection node (22), and the incoming wire (31) and the incoming wire (32) are respectively connected to the terminal block (33); The outer diameter edge (521) of the conductive coating (52) is provided with a plurality of first test nodes (531) uniformly distributed along the circumferential direction, and the inner diameter edge (522) of the conductive coating (52) is provided with a plurality of second test nodes (532) uniformly distributed along the circumferential direction, wherein the number of the second test nodes (532) is the same as the number of the first test nodes (531) and the second test nodes (532) are staggered along the circumferential direction; The lead wire (31) includes a first lead wire (311), a second lead wire (312), a wiring connector (313) and a transition wire (314); the wiring connector (313) is fixed to the sealed cavity (6); one end of the first lead wire (311) is connected to the first test node (531), and the other end is connected to the wiring connector (313); The resistance test module reads the resistance value change between two adjacent test nodes on the sealing ring in real time. The real-time change result is read by an external resistance test instrument and analyzed with the sealing ring surface coating wear-resistance correlation model obtained in advance. This can realize real-time on-site monitoring of the wear status of the built-in mechanical seal end face in service.

2. A testing system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: An annular groove (54) is provided on the outer peripheral surface of the insulating sealing ring base (51); the first lead wire (311) is fixed in the annular groove (54) by a clamping ring (55) to avoid contact with the dynamic ring (4); and the transition wire (314) of the first lead wire (311) between the static ring (5) and the wiring connector (313) is in a freely retractable spiral shape.

3. A testing system for monitoring seal surface wear based on conductive coating resistance change according to claim 2, characterized in that: The sealed cavity (6) is provided with a wire lead-out hole (61), one end of the second lead-out wire (312) is connected to the second test node (532), and the other end of the second lead-out wire (312) passes through the wire lead-out hole (61) to avoid contact with the rotating part.

4. The test system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: The conductive coating (52) has a resistivity of 10 -5 Ω·m to 10 7 Ω·m, the insulating sealing ring substrate (51) has a resistivity greater than 10 7 Ω·m insulator, the lead-out wire (31) and the lead-in wire (32) both have a resistivity of less than 10 -5 Ω·m conductor.

5. The test system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: One side surface (523) of the conductive coating (52) is tightly fitted to the end surface of the insulating sealing ring substrate (51); the other side surface (524) of the conductive coating (52) is a sealing surface; and the thickness of the conductive coating (52) is 1 μm to 500 μm.

6. The test system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: The dynamic ring (4) is fixed on the shaft sleeve (41) and rotates therewith, and the static ring (5) is floatingly installed in the sealing cavity (6). A push ring (56), an auxiliary sealing ring (57) and an elastic element (58) are provided between the static ring (5) and the sealing cavity (6).

7. The testing system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: The number of the first test nodes (531) is no less than 3.

8. The test system for monitoring seal surface wear based on conductive coating resistance change according to claim 1, characterized in that: The resistance test module (2) comprises a resistance test meter (21), a connection node (22), a resistance test box (23) and a resistance test cover (24); the resistance test box (23) is provided with a wire introduction hole (231) for an introduction wire (32) to pass through; the resistance test cover (24) is located above the resistance test box (23); and the resistance test meter (21) is embedded in the resistance test cover (24).

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