Pressure warning device for bearing cavity of centrifugal pump
By designing a bearing cavity pressure warning device in the centrifugal pump, the bearing cavity pressure is monitored by changes in liquid pressure, which solves the problem of increased bearing cavity pressure caused by mechanical seal failure. This enables timely maintenance and lubrication oil replacement, preventing damage to the bearing and spindle.
Patent Information
- Application Number
- CN202423298320.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-12-31
AI Technical Summary
During long-term use, the first mechanical seal between the bearing cavity and the impeller cavity of a centrifugal pump may fail, allowing water to enter the bearing cavity, increasing pressure, affecting the normal operation of the main shaft, and potentially causing oil leakage and corrosion.
A centrifugal pump bearing cavity pressure warning device was designed. Through a piston and indicator rod system, the indicator rod is moved by the change of liquid pressure to display a warning mark, reminding the staff to inspect and replace the lubricating oil in time to avoid damage to the bearing and spindle.
Effective monitoring of pressure changes within the bearing cavity reminds for maintenance and lubrication oil replacement, prevents corrosion of the bearings and spindle, and ensures normal operation of the centrifugal pump.
Smart Images
Figure CN223511135U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to centrifugal pumps, and more specifically to sealing devices. Background Technology
[0002] A centrifugal pump is a type of pump that uses the rotation of an impeller to cause the medium to move centrifugally. Under the action of centrifugal motion, the medium is thrown towards the edge of the impeller, creating a vacuum in the center to draw the medium in. The pump body of a centrifugal pump is cast and includes an impeller cavity and a bearing cavity. The main shaft passes through the bearing cavity and extends into the impeller cavity. The impeller is mounted on the main shaft extending into the impeller cavity. A bearing is installed in the bearing cavity to support the main shaft. A first mechanical seal is installed between the bearing cavity and the impeller cavity. As the impeller rotates, the pressure on its back increases, and the pressure on the first mechanical seal also increases. The bearing cavity is filled with lubricating oil. After long-term use, the function of the first mechanical seal may weaken or be lost. Water in the impeller cavity may enter the bearing cavity through the mechanical seal, causing the pressure inside the bearing cavity to increase. This can affect the normal operation of the main shaft. If the pressure is too high, it may cause oil to leak out of the bearing cavity. Moreover, the oil-water mixture in the bearing cavity can corrode the bearing and the main shaft. Utility Model Content
[0003] The technical problem solved by this utility model is that after long-term use, the first mechanical seal function between the bearing cavity and the impeller cavity of a centrifugal pump may be weakened or lost. Water in the impeller cavity enters the bearing cavity through the first mechanical seal, which leads to an increase in pressure inside the bearing cavity and affects the normal operation of the main shaft. If the pressure is too high, it may cause oil in the bearing cavity to leak out. Moreover, the oil-water mixture in the bearing cavity corrodes the bearing and the main shaft.
[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a centrifugal pump bearing cavity pressure warning device, including a combined mounting component and a piston movably fitted in the combined mounting component. The piston is connected to an indicator rod, and a spring is sleeved on the indicator rod. One end of the spring abuts against the piston, and the other end of the spring abuts against the inner cavity of the combined mounting component. The indicator rod protrudes outward from the combined mounting component, and a warning mark is provided on the indicator rod protruding outward from the combined mounting component. The combined mounting component is installed on the side wall of the pump body, and the piston is subjected to pressure from the oil in the bearing cavity.
[0005] According to the above technical solution, the pressure on the back of the impeller acts on the first mechanical seal. If water in the impeller cavity seeps into the bearing cavity through the first mechanical seal, due to the incompressibility of the liquid, the pressure inside the bearing cavity increases. This pressure increase may come directly from the increase in liquid volume or from the liquid compressing the gas inside the bearing cavity. The increased pressure inside the bearing cavity acts on the piston, causing the piston to move, which in turn moves the indicator rod, compressing the spring. The indicator rod protrudes outward from the assembly mounting piece. During maintenance or repair, personnel can determine whether the oil pressure inside the bearing cavity has increased based on the position of the warning mark on the indicator rod, and thus determine whether external liquid has seeped into the bearing cavity.
[0006] Threaded holes are made on the side wall of the pump body, and the assembly is screwed onto the side wall of the pump body.
[0007] The assembly includes a first threaded component and a second threaded component. The first threaded component has a first central through hole, and the second threaded component has a second central through hole. The second central through hole is smaller than the first central through hole. The second threaded component is screwed into the first central through hole. The piston is movably fitted into the first central through hole. The spring is fitted into the first central through hole. The indicator rod is movably fitted into the second central through hole. The indicator rod and the second central through hole have a clearance fit. The indicator rod can protrude outward from the second central through hole.
[0008] The first threaded component has a first step, which abuts against the side wall of the pump body, and a first sealing ring is provided between the first step and the side wall of the pump body.
[0009] The second threaded component has a second step, which abuts against the top surface of the first threaded component, and a second sealing ring is provided between the second step and the top surface of the first threaded component.
[0010] A third sealing ring is provided between the piston and the side wall of the first central through hole.
[0011] As an improvement, the pump body's bearing cavity is equipped with a central bearing and a tail bearing. The central bearing fits into an inner protrusion within the bearing cavity, and a second mechanical seal is mounted on the inner protrusion. The assembly is installed on the side wall of the pump body between the first and second mechanical seals. The second mechanical seal divides the bearing cavity into two chambers, with a warning device located in one of the chambers, close to the first mechanical seal. If the first mechanical seal leaks, the leaking liquid enters one chamber but not the other. This provides the following technical advantages: First, compared to the entire bearing cavity, the volume of one chamber is smaller, allowing the warning device to react quickly; second, the leaked water only contaminates the lubricating oil in one chamber, and the operator can remove the warning device and replace the oil through a threaded hole.
[0012] The second mechanical seal includes a sealing element and a sealing ring. The inner sidewall of the sealing element has several sealing grooves, which are distributed along the axial direction of the main shaft. The sealing ring engages in each sealing groove and is fitted on the main shaft, rotating with the main shaft. The sealing element is fixedly installed on the inner protrusion.
[0013] The warning device of this utility model can remind workers to inspect the mechanical seal in a timely manner and replace the lubricating oil in the bearing cavity to avoid damage to the bearing and spindle. Attached Figure Description
[0014] The present invention will be further described below with reference to the accompanying drawings:
[0015] Figure 1 This is a schematic diagram of the bearing cavity of a centrifugal pump.
[0016] Figure 2 for Figure 1 Partial schematic diagram at point A in the middle;
[0017] Figure 3 for Figure 1 A partial schematic diagram of point B in the middle.
[0018] Explanation of symbols in the diagram:
[0019] 10. Piston; 11. Indicator rod; 12. Third sealing ring;
[0020] 20. Spring;
[0021] 30. First threaded component; 31. First central through hole; 32. First step; 33. First sealing ring;
[0022] 40. Second threaded component; 41. Second central through hole; 42. Second step; 43. Second sealing ring;
[0023] 50. Pump body; 51. Bearing cavity; 52. Middle bearing; 53. Tail bearing; 54. Inner protrusion; 55. First mechanical seal; 56. Impeller cavity; 57. Main shaft;
[0024] 60. Second mechanical seal; 61. Sealing element; 62. Sealing ring. Detailed Implementation
[0025] Combination Figure 1 , Figure 2 The centrifugal pump bearing cavity pressure warning device includes a combined mounting component and a piston 10 movably fitted in the combined mounting component. The piston is connected to an indicator rod 11, and a spring 20 is sleeved on the indicator rod. One end of the spring abuts against the piston, and the other end of the spring abuts against the inner cavity of the combined mounting component. The indicator rod protrudes outward from the combined mounting component, and a warning mark is provided on the indicator rod protruding outward from the combined mounting component. The combined mounting component is installed on the side wall of the pump body 50, and the piston is subjected to pressure from the oil in the bearing cavity 51.
[0026] A threaded hole is opened on the side wall of the pump body 50, and the assembly is screwed onto the side wall of the pump body.
[0027] The assembly includes a first threaded component 30 and a second threaded component 40. The first threaded component has a first central through hole, and the second threaded component has a second central through hole 41. The second central through hole is smaller than the first central through hole. The second threaded component is screwed into the first central through hole. The piston 10 is movably fitted into the first central through hole. The spring 20 is fitted into the first central through hole. The indicator rod 11 is movably fitted into the second central through hole. The indicator rod is clearance-fitted with the second central through hole, and the indicator rod can protrude outward from the second central through hole.
[0028] The first threaded part 30 is provided with a first step 32, which abuts against the side wall of the pump body 50, and a first sealing ring 33 is provided between the first step and the side wall of the pump body.
[0029] The second threaded component 40 is provided with a second step 42, which abuts against the top surface of the first threaded component 30, and a second sealing ring 43 is provided between the second step and the top surface of the first threaded component.
[0030] A third sealing ring 12 is provided between the piston 10 and the side wall of the first central through hole 31.
[0031] The pump body 50 has a bearing cavity 51 containing a middle bearing 52 and a tail bearing 53. The middle bearing fits into the inner protrusion 54 of the bearing cavity, and a second mechanical seal 60 is installed on the inner protrusion. The assembly is installed on the side wall of the pump body between the first mechanical seal 55 and the second mechanical seal 60. Figure 3 The second mechanical seal 60 includes a sealing element 61 and a sealing ring 62. The inner sidewall of the sealing element has several sealing grooves, which are distributed along the axial direction of the main shaft 57. The sealing ring 62 is engaged in each sealing groove. The sealing ring is fitted on the main shaft and rotates with the main shaft. The sealing element 61 is fixedly installed on the inner protrusion 54.
[0032] The pressure on the back of the impeller acts on the first mechanical seal 55. If water in the impeller cavity 56 seeps into the bearing cavity 51 through the first mechanical seal, the pressure in the bearing cavity 51 increases due to the incompressibility of the liquid. This pressure increase may be directly due to the increase in liquid volume or due to the liquid compressing the gas in the bearing cavity. The increased pressure in the bearing cavity 51 acts on the piston 10, causing the piston to move and the indicator rod 11 to move, compressing the spring 20. The indicator rod protrudes outward from the second central through hole 41 of the second threaded part 40. During maintenance or repair, personnel can determine whether the oil pressure in the bearing cavity 51 has increased based on the position of the warning mark on the indicator rod 11, and thus determine whether water in the impeller cavity 56 has seeped into the bearing cavity 51.
[0033] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of this utility model. The content of this specification should not be construed as a limitation of this utility model.
Claims
1. A centrifugal pump bearing cavity pressure warning device, comprising a mounting assembly and a piston (10) movably fitted in the mounting assembly, characterized in that: The piston is connected to an indicator rod (11), and a spring (20) is fitted on the indicator rod. One end of the spring abuts against the piston, and the other end of the spring abuts against the inner cavity of the assembly. The indicator rod protrudes outward from the assembly and a warning mark is provided on the indicator rod protruding outward from the assembly. The assembly is installed on the side wall of the pump body (50), and the piston is subjected to the pressure of oil from the bearing cavity (51).
2. The centrifugal pump bearing cavity pressure warning device as described in claim 1, characterized in that: A threaded hole is opened on the side wall of the pump body (50), and the assembly is screwed onto the side wall of the pump body.
3. The centrifugal pump bearing cavity pressure warning device as described in claim 2, characterized in that: The assembly includes a first threaded part (30) and a second threaded part (40). The first threaded part has a first central through hole, and the second threaded part has a second central through hole (41). The second central through hole is smaller than the first central through hole. The second threaded part is screwed into the first central through hole. The piston (10) is movably fitted in the first central through hole. The spring (20) is fitted in the first central through hole. The indicator rod (11) is movably fitted in the second central through hole. The indicator rod and the second central through hole are in clearance fit. The indicator rod can protrude outward from the second central through hole.
4. The centrifugal pump bearing cavity pressure warning device as described in claim 3, characterized in that: The first threaded part (30) is provided with a first step (32), the first step abuts against the side wall of the pump body (50), and a first sealing ring (33) is provided between the first step and the side wall of the pump body.
5. The centrifugal pump bearing cavity pressure warning device as described in claim 3, characterized in that: The second threaded component (40) is provided with a second step (42), which abuts against the top surface of the first threaded component (30), and a second sealing ring (43) is provided between the second step and the top surface of the first threaded component.
6. The centrifugal pump bearing cavity pressure warning device as described in claim 2, characterized in that: A third sealing ring (12) is provided between the piston (10) and the side wall of the first central through hole (31).
7. The centrifugal pump bearing cavity pressure warning device as described in claim 1, characterized in that: The pump body (50) has a middle bearing (52) and a tail bearing (53) in the bearing cavity (51). The middle bearing is fitted in the inner protrusion (54) of the bearing cavity. A second mechanical seal (60) is installed on the inner protrusion. The combined mounting component is installed on the side wall of the pump body between the first mechanical seal (55) and the second mechanical seal (60).