Ceramic sealing device for corrosion and wear resistant centrifugal pump

Abstract

The application belongs to the technical field of centrifugal pumps, and particularly relates to a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump. The following scheme is provided, which comprises a pump shell, a rotor and an impeller. A sealing ring is arranged between the pump shell and the impeller. The sealing ring is provided with a metal retainer with an annular structure and a ceramic ring mounted in the metal retainer. The traditional metal sealing ring is replaced by the ceramic ring. Since the ceramic sealing ring has self-lubricating characteristics, the material surface layer has a water lubrication effect in high-speed rotation in a small gap, so that the running gap can be significantly reduced, thereby improving the hydraulic efficiency of the pump and the dynamic stability of the rotor, without the risk of rotation element jamming, greatly improving the service life of the water pump and improving the working efficiency.

Description

Technical Field

[0001] This invention relates to the field of centrifugal pump technology, and in particular to a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump. Background Technology

[0002] In complex operating conditions such as deep well drainage, seawater transportation, mining, and chemical production, multistage centrifugal pumps often need to transport non-clean water media such as slurry containing solid particles, corrosive seawater, or acid and alkali solutions. The sealing ring inside the pump body is installed between the casing and the impeller. Its main function is to reduce interstage leakage and ensure the pressure gradient of each stage and the hydraulic efficiency of the entire pump.

[0003] Traditional sealing rings are mostly made of metal materials, and a certain operating gap needs to be reserved between them and the impeller liner. A large operating gap will lead to excessive internal leakage between stages, thereby affecting hydraulic efficiency and causing the flow and efficiency of the whole pump to fail to reach the design value. A small sealing gap will cause the metal sealing ring to bite (melt), resulting in the rotor and stator seizing. Summary of the Invention

[0004] Based on the technical problems in the background art, the present invention proposes a ceramic sealing device for corrosion-resistant and wear-resistant centrifugal pumps.

[0005] The present invention proposes a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump, comprising a pump casing, a rotor and an impeller, wherein a sealing ring is provided between the pump casing and the impeller, and the sealing ring is provided with a metal cage with an annular structure and a ceramic ring installed in the metal cage.

[0006] Preferably, the ceramic ring is provided with multiple ceramic blocks, and the inner side of the metal retainer is provided with an annular mounting groove, in which the multiple ceramic blocks are arranged in an annular array and fixed in the mounting groove.

[0007] Preferably, the metal cage and the ceramic block are interference-fitted. The ceramic block is cooled to a low temperature of -100 to -200 degrees Celsius in liquid nitrogen. After the ceramic block shrinks due to the cold, it is mounted on the metal cage. At room temperature, the metal cage and the ceramic block are in a stable integrated state.

[0008] Preferably, multiple connectors are fixed in the mounting groove, and grooves adapted to the connectors are provided on both sides of the ceramic block facing the inner wall of the mounting groove. The connectors are provided with silicone sleeves that cover the outside.

[0009] Preferably, the connector includes a positioning plate fixed to the inner wall of the mounting groove, an air bag is installed on the positioning plate at a position away from the mounting groove, and a silicone sleeve is fixed to the outer wall of the air bag.

[0010] Preferably, the position of the air bag away from the positioning plate and the corresponding position of the silicone sleeve are both set in a V-shape, and a V-shaped rigid strip is fixed to the position of the air bag away from the positioning plate.

[0011] Preferably, the sealing ring is equipped with a pressure monitoring device for monitoring the internal pressure of the air bags. The pressure monitoring device includes multiple miniature pressure sensors, each corresponding to one air bag. The signal lines of the pressure sensors are connected to a data acquisition and processing unit, which continuously acquires the pressure values ​​of each air bag. The data acquisition and processing unit includes a signal conditioning circuit, an analog-to-digital converter module, a microprocessor, a memory, and an early warning module. The data acquisition and processing unit is also connected to a temperature sensor mounted on the pump casing, which measures the medium temperature in real time. The data acquisition and processing unit adjusts the collected pressure values ​​of each air bag based on the medium temperature. The pressure value is corrected for temperature, converting it to the equivalent pressure at the reference temperature, and the pressure decay amount and rate of decay for each air bag are calculated. The data acquisition and processing unit has a first threshold and a second threshold, with the second threshold being greater than the first threshold. When the pressure decay amount of a certain air bag exceeds the first threshold, the early warning module issues a first-level early warning signal to indicate significant fretting wear of the sealing ring. When the pressure decay amount exceeds the second threshold, the early warning module issues a second-level early warning signal to indicate severe loss of preload. When the pressure decay rate exceeds a preset rate threshold, the early warning module issues an alarm signal to indicate the risk of sudden failure.

[0012] The beneficial effects of this invention are as follows: In this invention, a ceramic ring is used instead of a traditional metal sealing ring. Because the ceramic sealing ring has self-lubricating properties and the surface of the material rotates at high speed in a small gap, the water lubrication effect can be achieved, thus significantly reducing the operating gap. This improves the hydraulic efficiency of the pump and the dynamic stability of the rotor without the risk of rotating components getting stuck, greatly extending the pump's lifespan and improving its working efficiency.

[0013] In this invention, the silicone sleeve wrapped around the air bag makes contact with the two adjacent ceramic blocks, allowing for a small adjustment margin between each small block, ensuring the stability and sealing of the connection. When the ceramic blocks on both sides are installed with an interference fit, the silicone sleeve can be squeezed to further improve the stability of the installation. Furthermore, the silicone sleeve can be used to seal when the ceramic blocks are slightly deformed or shifted, thereby ensuring the sealing effect.

[0014] In this invention, by monitoring the attenuation trend of the static pressure of the air bag, the preload loss caused by long-term fretting wear of the ceramic block can be indirectly determined, which can effectively warn of ceramic block wear and preload failure, thereby avoiding serious faults such as decreased hydraulic efficiency, increased vibration, and even rotor jamming caused by uncontrolled sealing gaps, and significantly improving the intelligent level of operation and maintenance and operational reliability of centrifugal pumps. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the overall structure of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 2 This is an enlarged structural diagram of the sealing ring position of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 3 This is a schematic diagram of the sealing ring structure of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 4 This is a schematic diagram of the metal cage structure of a ceramic seal device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 5 This is a schematic diagram of the ceramic block structure of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 6 This is a schematic diagram of the connecting component structure of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention; Figure 7 This is a schematic diagram of the positioning plate, air bag, and rigid strip plate of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention. Figure 8 This is a schematic cross-sectional view of the connecting part of a ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump proposed in this invention.

[0016] In the diagram: 1 Pump casing, 2 Rotor, 3 Impeller, 4 Sealing ring, 41 Metal cage, 411 Mounting groove, 42 Ceramic ring, 421 Ceramic block, 422 Groove, 43 Connector, 431 Positioning plate, 432 Air bag, 433 Silicone sleeve, 434 Rigid strip plate. Detailed Implementation

[0017] Example 1: Refer to Figures 1-2A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump includes a pump casing 1, a rotor 2, and an impeller 3. The rotor 2 is rotatably mounted inside the pump casing 1 via a sealed bearing, and one end of the rotor 2 is connected to a motor. Multiple impellers 3 are fixed to the outer wall of the rotor 2, thus forming a multi-stage centrifugal pump. A sealing ring 4 is provided between the pump casing 1 and the impeller 3. An impeller bushing is mounted on the impeller 3 at a position corresponding to the sealing ring 4 via pins. The outer circumference of the impeller bushing corresponds to the inner wall of the sealing ring 4, with a gap between them. The multi-stage pump based on the combination of the pump casing 1, rotor 2, impeller 3, and sealing ring 4 is a conventional method in this field, and its specific composition and structure will not be described in detail. The sealing ring 4 is provided with a ring-shaped metal retainer 41 and a ceramic ring 42 installed in the metal retainer 41. By replacing the traditional metal sealing ring with the ceramic ring 42, the operating gap can be significantly reduced due to the self-lubricating properties of the ceramic sealing ring and the water lubrication effect of the material surface rotating at high speed in a small gap. This improves the hydraulic efficiency of the pump and the dynamic stability of the rotor without the risk of rotating components getting stuck, greatly improving the pump's lifespan and working efficiency. It should be further noted that this structure is not limited to multi-stage pumps; single-stage pumps, magnetic pumps, and other pump bodies can also use this ceramic sealing ring structure.

[0018] In this invention, the ceramic ring 42 is made of wear-resistant and corrosion-resistant ceramic material. The metal retainer 41 and the ceramic ring 42 are interference-fitted. The ceramic ring 42 is cooled to a low temperature of -100 to -200 degrees Celsius in liquid nitrogen. After the ceramic ring 42 shrinks due to the cold, it is installed on the metal retainer 41. At room temperature, the metal retainer 41 and the ceramic ring 42 are in a stable integrated state, which can effectively prevent them from falling off.

[0019] Example 2: A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump. Based on Example 1, the ceramic ring 42 is an integral cylindrical ring structure. The inner side of the metal retainer 41 is provided with a ring-shaped fixing groove. The ceramic ring 42 is installed in the fixing groove and is embedded into the inner side of the metal retainer 41 by an integral cold-fitting process. In this example, the ceramic ring 42 adopts an integral structure without splicing gaps or adhesive interfaces, eliminating the risk of media leakage and corrosion.

[0020] Example 3: Reference Figures 1-8A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump, based on embodiment 1, includes a ceramic ring 42 with multiple ceramic blocks 421, and a ring-shaped mounting groove 411 on the inner side of a metal retainer 41. The multiple ceramic blocks 421 are arranged in a ring array and fixed in the mounting groove 411. By dividing the ceramic ring 42 into small pieces, the internal stress can be effectively dispersed, reducing the risk of breakage. The metal retainer 41 and the ceramic blocks 421 are interference-fitted. The ceramic blocks 421 are cooled to a low temperature of -100 to -200 degrees Celsius in liquid nitrogen. After the ceramic blocks 421 shrink due to cooling, they are installed on the metal retainer 41. At room temperature, the metal retainer 41 and the ceramic blocks 421 are in a stable integrated state, preventing the ceramic blocks 421 from falling off and rotating with the impeller 3.

[0021] In this invention, multiple connectors 43 are fixed in the mounting groove 411. The connectors 43 extend axially in the rotor 2. Both sides of the ceramic block 421 are provided with grooves 422 that are adapted to the connectors 43. The connectors 43 are provided with silicone sleeves 433 that are externally wrapped. The silicone sleeves 433 contact the inner wall of the grooves 422, thereby installing the ceramic block 421 between two adjacent connectors 43. By using the silicone sleeves 433 that are externally wrapped in the connectors 43 to contact the two adjacent ceramic blocks 421, a small adjustment margin can be allowed between each small block, ensuring the stability and sealing of the connection.

[0022] In this invention, the connector 43 includes a positioning plate 431 fixed to the inner wall of the mounting groove 411. An air bag 432 is installed on the positioning plate 431 away from the mounting groove 411. A silicone sleeve 433 is fixed to the outer wall of the air bag 432. Both the positioning plate 431 and the air bag 432 extend axially in the rotor 2. It should also be noted that the silicone sleeve 433 covers both sides, both ends, and the position away from the positioning plate 431 of the air bag 432. Both ends of the air bag 432 extend a certain distance beyond the positioning plate 431. Thus, when the ceramic blocks 421 on both sides are interference-fitted, the silicone sleeve 433 can be squeezed, further improving the stability of the installation. The silicone sleeve 433 can also be used to seal when the ceramic blocks 421 are slightly deformed or displaced, thereby ensuring a sealing effect.

[0023] In this invention, the position of the air bag 432 away from the positioning plate 431 and the corresponding position of the silicone sleeve 433 are both set in a V-shape. The corresponding part of the groove 422 of the ceramic block 421 is adapted to it. A V-shaped rigid strip plate 434 is fixed at the position of the air bag 432 away from the positioning plate 431. The rigid strip plate 434 is in contact with the inner wall of the silicone sleeve 433. The rigid strip plate 434 can be made of ceramic material or metal material. The rigid strip plate 434 faces the inner ring of the ceramic ring 42. The compression operation of the rigid strip plate 434 can ensure the stability and sealing of the inner ring connection of the ceramic ring 42. When the deformation or displacement of the adjacent ceramic blocks 421 causes the inner ring gap to increase, the silicone sleeve 433 can be compressed by the rigid strip plate 434 to improve the sealing effect, thereby improving the effectiveness of the centrifugal pump for long-term use.

[0024] Example 4: Reference Figures 1-8 A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump, based on Example 3, further provides a method for monitoring the long-term fretting wear of the ceramic block based on the static pressure decay trend of the air bag, so as to realize online judgment and early warning of the effective pre-tightening state of the sealing ring.

[0025] In this invention, an air bag pressure monitoring device is provided on the sealing ring 4. Specifically, a through microhole is opened on the positioning plate 431 of each connector 43. The microhole communicates with the internal cavity of the air bag 432. A miniature pressure sensor is fixedly installed on the outer wall of the metal retainer 41 at the position corresponding to each air bag 432. The sensing end of the pressure sensor is connected to the microhole through a sealed pipeline, thereby measuring the gas pressure inside the air bag 432 in real time. The signal line of the pressure sensor is led out of the pump housing 1 along the outer wall of the metal retainer 41 and connected to the external data acquisition and processing unit. As an alternative, the pressure sensor can be directly embedded inside the positioning plate 431, as long as it can sense the pressure of the air bag 432.

[0026] In this invention, the data acquisition and processing unit includes a signal conditioning circuit, an analog-to-digital conversion module, a microprocessor, and a memory. The data acquisition and processing unit continuously acquires the pressure values ​​of each air bag 432 at a set sampling frequency, denoted as P_i, where the subscript i represents the number of the i-th air bag in the sealing ring 4. For a multi-stage centrifugal pump, each sealing ring 4 is equipped with an independent air bag pressure monitoring device, and each pressure signal is acquired and processed separately.

[0027] In this invention, after the centrifugal pump is initially installed, debugged, and enters a stable operating phase, an initial benchmark is established. The specific steps are as follows: After the pump runs continuously under rated conditions for a period of time, the pressure value of each air bag 432 is recorded as the initial benchmark pressure P_i0. This initial benchmark pressure reflects the contact clamping force between the ceramic block 421 and the silicone sleeve 433 in a healthy state. At the same time, the corresponding pump operating parameters are also recorded, including speed, flow rate, outlet pressure, medium temperature, etc., as a reference for subsequent pressure correction. For the sealing ring 4 of the same model produced in batches, the standard value of the air bag pressure under different preloads can also be measured in advance on the test bench as the factory benchmark.

[0028] In this invention, during the long-term operation of the centrifugal pump, the data acquisition and processing unit continuously monitors the real-time pressure P_it of each gas bag 432, where t represents the operating time. Since changes in medium temperature cause thermal expansion and contraction of the gas inside the gas bag 432, resulting in pressure reading drift, temperature compensation is required. To this end, a temperature sensor is installed near the sealing ring 4 on the pump casing 1 to measure the medium temperature T in real time. The data acquisition and processing unit corrects the measured pressure according to the ideal gas law, converting the pressure value to the equivalent pressure P_i_corrt=P_it×T0 / T at the reference temperature T0, where T and T0 are both thermodynamic temperatures.

[0029] Then, the pressure decay amount ΔP_it=P_i0-P_i_corrt for each air bag 432 and the pressure decay rate v_it=d(ΔP_i) / dt are calculated. The pressure decay rate can be obtained by linearly fitting ΔP_it within a time window. The data acquisition and processing unit is also equipped with a comparator and an early warning module. When the ceramic block 421 experiences fretting wear during long-term operation, the contact surface between the groove 422 surface of the ceramic block 421 and the silicone sleeve 433 is gradually worn away, resulting in a reduction in the squeezing force of the ceramic block 421 on the air bag 432. The static pressure inside the air bag 432 then slowly decreases. This pressure drop is not caused by air bag leakage, but is a direct reflection of the wear of the ceramic block. By monitoring the pressure decay trend of the air bag, the wear degree of the ceramic block 421 and the effective pre-tightening state of the sealing ring 4 can be quantitatively assessed.

[0030] In this invention, the data acquisition and processing unit sets a first threshold and a second threshold for the pressure attenuation ΔP_it, wherein the second threshold is greater than the first threshold. When the pressure attenuation ΔP_i of a certain air bag 432 continues to increase and exceeds the first threshold, it is determined that the two adjacent ceramic blocks 421 corresponding to the air bag have undergone significant fretting wear, the effective pre-tightening force has decreased, and the overall sealing performance of the sealing ring 4 may have been affected. At this time, the early warning module issues a first-level early warning signal, prompting the operator to check or replace the sealing ring 4 during the next shutdown maintenance. When the pressure attenuation ΔP_i further increases and exceeds the second threshold, it is determined that the ceramic block 421 in this area is severely worn, the pre-tightening force is insufficient to maintain a stable sealing gap, the hydraulic efficiency of the pump may decrease significantly, and there is a potential risk of the ceramic block loosening or falling off. At this time, the warning module issues a second-level warning signal and recommends to arrange shutdown and maintenance as soon as possible.

[0031] In this invention, the pressure decay rate v_it is also monitored. If the v_i value of a certain air bag 432 increases significantly in a short period of time, that is, the pressure drops rapidly, it may indicate that the ceramic block 421 at that location has been locally broken or the edge of the groove 422 has peeled off, resulting in a sharp loss of clamping force. At this time, even if ΔP_i has not yet reached the first threshold, an alarm signal should be issued immediately to indicate the risk of sudden failure.

[0032] In this invention, for multi-stage centrifugal pumps, the data acquisition and processing unit also performs a lateral comparison of the pressure attenuation of the air bags between each sealing ring 4: if the pressure attenuation of all air bags in a certain stage sealing ring 4 is generally large, it indicates that the overall wear of the sealing ring in that stage is severe; if only the pressure attenuation of individual air bags in a certain stage sealing ring is abnormal, it indicates that there is a local abnormality in the ceramic block corresponding to that position.

[0033] In this invention, the data acquisition and processing unit is also equipped with a storage module for recording the pressure history curve of each air bag 432. Maintenance personnel can view the pressure decay trend graph through an external terminal and, in conjunction with the pump's cumulative operating time and changes in operating conditions, formulate predictive maintenance plans.

[0034] This embodiment indirectly determines the loss of preload caused by long-term fretting wear of ceramic block 421 by monitoring the attenuation trend of static pressure in air bag 432. This enables online assessment of the health status of the sealing ring. By adding an external pressure sensor and data processing unit, it is possible to effectively warn of ceramic block wear and preload failure, thereby avoiding serious faults such as decreased hydraulic efficiency, increased vibration, and even rotor jamming caused by uncontrolled sealing gap. This significantly improves the intelligent operation and maintenance level and operational reliability of centrifugal pumps.

[0035] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump, comprising a pump casing (1), a rotor (2), and an impeller (3), wherein a sealing ring (4) is provided between the pump casing (1) and the impeller (3), characterized in that, The sealing ring (4) is provided with a metal retainer (41) with an annular structure and a ceramic ring (42) installed in the metal retainer (41).

2. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 1, characterized in that, The metal retainer (41) and the ceramic ring (42) are interference fit. The ceramic ring (42) is cooled to a low temperature of -100 to -200 degrees Celsius in liquid nitrogen. After the ceramic ring (42) shrinks due to the cold, it is installed on the metal retainer (41). At room temperature, the metal retainer (41) and the ceramic ring (42) are in a stable integrated state.

3. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 2, characterized in that, The ceramic ring (42) is an integral cylindrical ring structure.

4. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 2, characterized in that, The ceramic ring (42) is provided with multiple ceramic blocks (421), and the metal retainer (41) is provided with an annular mounting groove (411) on the inner side. The multiple ceramic blocks (421) are arranged in an annular array and fixed in the mounting groove (411).

5. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 4, characterized in that, Multiple connectors (43) are fixed inside the mounting groove (411). The ceramic block (421) has grooves (422) on both sides facing the inner wall of the mounting groove (411) that are adapted to the connectors (43). The connectors (43) are provided with silicone sleeves (433) that are wrapped on the outside.

6. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 5, characterized in that, The connector (43) includes a positioning plate (431) fixed to the inner wall of the mounting groove (411), an air bag (432) is installed on the positioning plate (431) away from the mounting groove (411), and a silicone sleeve (433) is fixed to the outer wall of the air bag (432).

7. The ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 6, characterized in that, The position of the air bag (432) away from the positioning plate (431) and the corresponding position of the silicone sleeve (433) are both set in a V-shaped structure, and a V-shaped rigid strip plate (434) is fixed at the position of the air bag (432) away from the positioning plate (431).

8. A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to any one of claims 6 to 7, characterized in that, The sealing ring (4) is provided with a pressure monitoring device for monitoring the internal pressure of the air bag (432). The pressure monitoring device includes multiple miniature pressure sensors, each miniature pressure sensor corresponding to one air bag (432). The signal line of the pressure sensor is connected to the data acquisition and processing unit, which is used to continuously collect the pressure value of each air bag (432).

9. A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 8, characterized in that, The data acquisition and processing unit includes a signal conditioning circuit, an analog-to-digital conversion module, a microprocessor, a memory and an early warning module. The data acquisition and processing unit is also connected to a temperature sensor installed on the pump casing (1). The temperature sensor is used to measure the medium temperature in real time. The data acquisition and processing unit performs temperature compensation correction on the collected air bag pressure value according to the medium temperature, converts the pressure value to the equivalent pressure at the reference temperature, and calculates the pressure attenuation amount and pressure attenuation rate of each air bag (432).

10. A ceramic sealing device for a corrosion-resistant and wear-resistant centrifugal pump according to claim 9, characterized in that, The data acquisition and processing unit is equipped with a first threshold and a second threshold, the second threshold being greater than the first threshold: when the pressure decay of a certain air bag (432) exceeds the first threshold, the early warning module issues a first-level early warning signal to indicate that the sealing ring (4) has undergone significant fretting wear; when the pressure decay exceeds the second threshold, the early warning module issues a second-level early warning signal to indicate that the preload is severely lost; when the pressure decay rate exceeds the preset rate threshold, the early warning module issues an alarm signal to indicate the risk of sudden failure.

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