Centrifugal pump ring seal structure

Abstract

The present application relates to the field of centrifugal pump, specifically to the centrifugal pump mouth ring sealing structure, a plurality of pump body mouth ring segments are arranged between two pump body mouth ring cover rings, pump body mouth ring gaskets are arranged between two adjacent pump body mouth ring segments and between the pump body mouth ring cover ring and the adjacent pump body mouth ring segment; a plurality of impeller mouth ring segments are arranged between two impeller mouth ring cover rings, impeller mouth ring gaskets are arranged between two adjacent impeller mouth ring segments and between the impeller mouth ring cover ring and the adjacent impeller mouth ring segment; corresponding pump body mouth ring cover rings and impeller mouth ring cover rings, corresponding pump body mouth ring segments and impeller mouth ring segments are respectively provided with running gaps, corresponding pump body mouth ring gaskets and impeller mouth ring gaskets are respectively provided with annular grooves, the running gap is communicated with two annular grooves located on the opposite sides, and the plurality of running gaps are staggered in the radial direction, forming a continuous H-shaped labyrinth channel between the pump body mouth ring and the impeller mouth ring.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal pump sealing, in particular to a centrifugal pump orifice ring sealing structure. Background Art

[0002] In a centrifugal pump, the mouth ring (also known as a sealing ring or clearance ring) is a key structural component located between the pump body and the impeller. Its primary function is to prevent fluid leakage, reduce axial forces, and ensure effective sealing by forming a seal and controlling the gap between the impeller and the pump casing. During high-speed rotation, the impeller of a centrifugal pump may undergo slight radial displacement due to thermal expansion, manufacturing errors, or installation deviations. If the mouth ring clearance is too small, the impeller may directly contact the pump casing, causing severe wear, damage, or even pump failure. Appropriate mouth ring clearance provides space to accommodate these deviations, preventing mechanical interference between components and improving the operational reliability and service life of the pump.

[0003] The design of the ring and its clearance size have a significant impact on the performance of a centrifugal pump. The size and shape of the ring clearance directly influence the pump's leakage, efficiency, and operational stability. Optimizing the ring clearance is particularly critical in pump designs that strive for high performance and low energy consumption.

[0004] Existing centrifugal pump mouth rings, such as the utility model patent with application number CN201420753542.1, disclose a centrifugal pump impeller mouth ring and pump body sealing ring structure, including an impeller mouth ring and a pump body sealing ring that cooperate with each other, and a labyrinth sealing groove is opened in the area on the outer surface of the impeller mouth ring.

[0005] The existing centrifugal pump mouth ring is a single-sided groove structure, with grooves only on the pump body mouth ring or the impeller mouth ring, which cannot effectively prevent liquid backflow and leakage, affecting the efficiency and operating stability of the pump. Summary of the Invention

[0006] The object of the present invention is to provide a centrifugal pump mouth ring sealing structure, which improves the hydraulic performance of the pump while ensuring that the mouth ring gap meets the operating clearance, so as to solve the defects mentioned in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A centrifugal pump mouth ring sealing structure includes a pump body mouth ring and an impeller mouth ring that cooperate with each other, the pump body mouth ring includes two pump body mouth ring cover rings arranged along the axial direction, a plurality of pump body mouth ring ring sheets evenly spaced are provided between the two pump body mouth ring cover rings, and a pump body mouth ring gasket is respectively provided between two adjacent pump body mouth ring sheets and between the pump body mouth ring cover ring and the adjacent pump body mouth ring sheet; the impeller mouth ring includes two impeller mouth ring cover rings arranged along the axial direction, a plurality of impeller mouth ring ring sheets evenly spaced are provided between the two impeller mouth ring cover rings, the impeller mouth ring sheets correspond one to one with the pump body mouth ring sheets, and an impeller mouth ring gasket is respectively provided between two adjacent impeller mouth ring sheets and between the impeller mouth ring cover ring and the adjacent impeller mouth ring sheet.

[0009] As a further improvement, operating gaps are respectively provided between the corresponding pump body mouth ring cover ring and the impeller mouth ring cover ring, and between the corresponding pump body mouth ring sheet and the impeller mouth ring sheet, and annular grooves are respectively provided between the corresponding pump body mouth ring gasket and the impeller mouth ring gasket, and the operating gap connects the two annular grooves located on opposite sides thereof.

[0010] As a further improvement, the plurality of operating gaps are staggered in the radial direction.

[0011] As a further improvement, the radial width of the operating gap is A, the axial thickness of the pump body mouth ring gasket and the impeller mouth ring gasket is B, the axial thickness of the pump body mouth ring sheet and the impeller mouth ring sheet is C, the minimum radial distance between the operating gap and the inner circumferential wall of the annular groove and the minimum radial distance between the operating gap and the outer circumferential wall of the annular groove are D, the minimum radial distance between two adjacent operating gaps is E, and the maximum axial displacement of the impeller is S; D≥4A, E≥2D, B≥S, C≥2B.

[0012] As a further improvement, the pump body mouth ring cover ring, the pump body mouth ring ring sheet, and the pump body mouth ring gasket are coaxially arranged and fit together in pairs; the impeller mouth ring cover ring, the impeller mouth ring ring sheet, and the impeller mouth ring gasket are coaxially arranged and fit together in pairs.

[0013] As a further improvement, the pump body mouth ring piece includes a pump body mouth ring piece I and a pump body mouth ring piece II with different inner diameters, and the pump body mouth ring piece I and the pump body mouth ring piece II are arranged alternately.

[0014] As a further improvement, the impeller mouth ring segment includes an impeller mouth ring segment I and an impeller mouth ring segment II with different outer diameters, and the impeller mouth ring segment I and the impeller mouth ring segment II are arranged alternately.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] Multiple operating gaps are staggered radially to form a continuous H-shaped labyrinth channel between the pump body ring and the impeller ring, effectively improving the backflow and leakage prevention capabilities between the pump body ring and the impeller ring, thereby improving the efficiency and operation stability of the centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a structural diagram of an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 An enlarged schematic diagram of the pump body mouth ring and impeller mouth ring in part I.

[0020] Figure 3 It is a schematic diagram of the existing mouth ring structure.

[0021] Figure 4 This is the performance curve of the pump under the existing mouth ring.

[0022] Figure 5 Schematic diagram of the improved design of the mouth ring structure with L=22mm.

[0023] Figure 6 Schematic diagram of the improved design of the mouth ring structure with L=25mm.

[0024] Figure 7 Schematic diagram of the improved design of the mouth ring structure with L=38mm.

[0025] Figure 8 This is the flow-head curve.

[0026] Figure 9 This is the flow-shaft power curve.

[0027] Figure 10 This is the flow rate-pump efficiency curve.

[0028] In the figure: 1-pump casing; 2-impeller; 3-pump body ring; 4-impeller ring; 5-pump body ring cover; 6-pump body ring disc; 7-pump body ring gasket; 8-impeller ring cover; 9-impeller ring disc; 10-impeller ring gasket; 11-operating clearance; 12-annular groove; 61-pump body ring disc I; 62-pump body ring disc II; 91-impeller ring disc I; 92-impeller ring disc II. DETAILED DESCRIPTION

[0029] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] like Figure 1 and Figure 2 As shown, the centrifugal pump mouth ring sealing structure includes a pump body mouth ring 3 and an impeller mouth ring 4 that cooperate with each other. The pump body mouth ring 3 is nested outside the impeller mouth ring 4; the impeller mouth ring 4 is sleeved on the outer wall of the impeller 2 inlet, and the pump body mouth ring 3 is embedded in the inner wall of the pump casing 1 of the centrifugal pump.

[0031] The pump body mouth ring 3 includes two pump body mouth ring cover rings 5 ​​arranged along the axial direction, a plurality of pump body mouth ring slices 6 are arranged evenly spaced between the two pump body mouth ring cover rings 5, and a pump body mouth ring gasket 7 is respectively arranged between two adjacent pump body mouth ring slices 6 and between the pump body mouth ring cover ring 5 and the adjacent pump body mouth ring slices 6. In this embodiment, the pump body mouth ring cover ring 5, the pump body mouth ring slices 6, and the pump body mouth ring gasket 7 are coaxially arranged in an annular shape and fit in pairs. The outer diameters of the pump body mouth ring cover ring 5, the pump body mouth ring slices 6, and the pump body mouth ring gasket 7 are consistent. A step surface for abutting against one of the pump body mouth ring cover rings 5 ​​is provided on the inner wall of the pump housing 1. The other pump body mouth ring cover ring 5 can be fixed to the pump housing 1 by screws, so that the pump body mouth ring slices 6 and the pump body mouth ring gasket 7 located on the inner side are pressed by the two pump body mouth ring cover rings 5.

[0032] The impeller ring 4 includes two impeller ring cover rings 8 arranged in the axial direction, and a plurality of impeller ring segments 9 are arranged evenly spaced between the two impeller ring cover rings 8. The impeller ring segments 9 correspond to the pump body ring segments 6 one by one, and an impeller ring gasket 10 is respectively provided between two adjacent impeller ring segments 9 and between the impeller ring cover ring 8 and the adjacent impeller ring segment 9. In this embodiment, the impeller ring cover ring 8, the impeller ring piece 9, and the impeller ring gasket 10 are coaxially arranged in annular shapes and fit together in pairs. The inner diameters of the impeller ring cover ring 8, the impeller ring piece 9, and the impeller ring gasket 10 are consistent. A step surface for abutting one of the impeller ring cover rings 8 is provided on the outer wall at the inlet of the impeller 2. The other impeller ring cover ring 8 can be fixed to the outer wall at the inlet of the impeller 2 by screws, so that the impeller ring piece 9 and the impeller ring gasket 10 located on the inner side are pressed by the two impeller ring cover rings 8.

[0033] An operating gap 11 is provided between the corresponding pump body mouth ring cover ring 5 and the impeller mouth ring cover ring 8, and between the corresponding pump body mouth ring piece 6 and the impeller mouth ring piece 9. The operating gap 11 is a conventional pump mouth ring design gap. An annular groove 12 is provided between the corresponding pump body mouth ring gasket 7 and the impeller mouth ring gasket 10. The operating gap 11 connects the two annular grooves 12 located on the opposite sides thereof.

[0034] In this embodiment, the pump body ring piece 6 includes a pump body ring piece I 61 and a pump body ring piece II 62 with different inner diameters, the inner diameter of the pump body ring piece I 61 is smaller than the inner diameter of the pump body ring piece II 62, and the pump body ring piece I 61 and the pump body ring piece II 62 are staggered; the impeller ring piece 9 includes an impeller ring piece I 91 and an impeller ring piece II 92 with different outer diameters, the outer diameter of the impeller ring piece I 91 is smaller than the outer diameter of the impeller ring piece II 92, the impeller ring piece I 91 and the impeller ring piece II 92 are staggered, and the impeller ring piece Ring piece I 91 and impeller ring piece II 92 correspond to pump body ring piece I 61 and pump body ring piece II 62, respectively. The inner diameter of pump body ring cover ring 5 is consistent with the inner diameter of pump body ring piece I 61 or the inner diameter of pump body ring piece II 62, and the inner diameter of pump body ring cover ring 5 is inconsistent with the inner diameter of the adjacent pump body ring piece 6. The outer diameter of impeller ring cover ring 8 is consistent with the outer diameter of impeller ring piece I 91 or the outer diameter of impeller ring piece II 92, and the outer diameter of impeller ring cover ring 8 is inconsistent with the outer diameter of the adjacent impeller ring piece 9. An operating clearance 11 is provided between the corresponding pump body ring cover ring 5 and impeller ring cover ring 8, between the corresponding pump body ring piece I 61 and impeller ring piece I 91, and between the corresponding pump body ring piece II 62 and impeller ring piece II 92.

[0035] By adopting the above structure, multiple operating gaps 11 are staggered in the radial direction, thereby forming a continuous H-shaped labyrinth channel between the pump body mouth ring 3 and the impeller mouth ring 4, and the long and short raised tooth structures are arranged alternately. Finally, the axial dimension of the mouth ring is smaller than L, and L is the longest design axial dimension of the mouth ring.

[0036] On the premise of ensuring that the design of the operating gap 11 meets the requirements, the backflow prevention and leakage prevention capabilities between the pump body ring 3 and the impeller ring 4 are effectively improved, thereby improving the efficiency and operation stability of the centrifugal pump.

[0037] In this embodiment, the radial width of the operating gap 11 is A; the axial thickness of the pump body ring gasket 7 and the impeller ring gasket 10 is B; the axial thickness of the pump body ring plate 6 and the impeller ring plate 9 is C; the minimum radial distance between the operating gap 11 and the inner peripheral wall of the annular groove 12 and the minimum radial distance between the operating gap 11 and the outer peripheral wall of the annular groove 12 are both D. Specifically, the minimum radial distance between the operating gap 11 and the inner peripheral wall of the annular groove 12 is the minimum radial distance between the outer peripheral wall of the impeller ring plate I91 and the impeller ring gasket 10. The minimum radial distance between the operating gap 11 and the outer peripheral wall of the annular groove 12 is the radial distance between the inner peripheral wall of the pump body mouth ring segment II 62 and the inner peripheral wall of the pump body mouth ring gasket 7; the minimum radial distance between two adjacent operating gaps 11 is E, specifically, the minimum radial distance between two adjacent operating gaps 11 is the radial distance between the inner peripheral wall of the pump body mouth ring segment I 61 and the outer peripheral wall of the impeller mouth ring segment II 92; the maximum axial displacement of the impeller 2 is S; D ≥ 4A, E ≥ 2D, B ≥ S, C ≥ 2B.

[0038] Taking OHA80-400 pump as an example, the design point flow rate is 284m 3 / h, speed 2980r / min, diameter at the mouth ring gap is 207mm, according to API 610 standard (full name: "Specifications for Design, Manufacturing and Testing of Centrifugal Pumps for Petroleum and Natural Gas Industries"), the gap A = 0.5mm, the axial length L of the mouth ring is 22mm, and the maximum axial design dimension of the mouth ring is 38mm.

[0039] The distribution of proto-oral rings is as follows Figure 3 As shown, after installation, the performance obtained through CFD calculation is as follows Figure 4 As shown, the highest efficiency is 71.81%.

[0040] The sealing structure of the H-shaped labyrinth channel designed according to the present invention is as follows Figure 5-7 As shown, D = 4A = 2mm, E = 5mm (≥ 2D = 4mm), take the maximum axial displacement of the impeller S = 1mm, B = S = 1mm, C = 2mm (≥ 2B = 2mm), where Figure 5 Middle L=22mm, Figure 6Middle L=25mm, Figure 7 L = 38mm, based on the same CFD calculation method, the hydraulic performance under the above different mouth ring conditions was obtained. Figure 8 The middle is the comparison result of lift under different flow conditions. It can be seen that the improved mouth ring seal structure improves the lift under each flow condition. Figure 9 The middle is the shaft power curve. It can be seen that under different flow conditions, the improved design of the ring reduces the shaft power. Figure 10 The pump efficiency curve shows that under different flow conditions, the improved design of the ring improves the pump efficiency and does not change the highest efficiency flow point.

[0041] Table 1 Pump efficiency values ​​under different fluid conditions

[0042]

[0043] The following table shows the efficiency improvement values ​​at different flow rates. It can be seen that increasing the number of stacking layers can continuously improve the pump efficiency. For example, at a rated flow rate of 284m 3 / h, the efficiency improvement value increases from 5.44% to 6.87%, so when using the patented method of the present invention, the number of ring stacking layers can be increased as much as possible under the condition allowed by L.

[0044]

[0045] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A centrifugal pump mouth ring sealing structure, comprising a pump body mouth ring and an impeller mouth ring that cooperate with each other, characterized in that: The pump body mouth ring comprises two pump body mouth ring cover rings arranged along the axial direction, a plurality of pump body mouth ring ring sheets arranged evenly spaced are provided between the two pump body mouth ring cover rings, and a pump body mouth ring gasket is respectively provided between two adjacent pump body mouth ring ring sheets and between the pump body mouth ring cover ring and the adjacent pump body mouth ring ring sheet; the impeller mouth ring comprises two impeller mouth ring cover rings arranged along the axial direction, a plurality of impeller mouth ring ring sheets arranged evenly spaced are provided between the two impeller mouth ring cover rings, the impeller mouth ring sheets correspond to the pump body mouth ring sheets one by one, and an impeller mouth ring gasket is respectively provided between two adjacent impeller mouth ring ring sheets and between the impeller mouth ring cover ring and the adjacent impeller mouth ring sheet; An operating gap is provided between the corresponding pump body ring cover ring and the impeller ring cover ring, and between the corresponding pump body ring piece and the impeller ring piece, and an annular groove is provided between the corresponding pump body ring gasket and the impeller ring gasket, and the operating gap communicates with the two annular grooves located on opposite sides thereof; The plurality of operating gaps are staggered in the radial direction; The radial width of the operating clearance is A, the axial thickness of the pump body mouth ring gasket and the impeller mouth ring gasket is B, the axial thickness of the pump body mouth ring plate and the impeller mouth ring plate is C, the minimum radial distance between the operating clearance and the inner peripheral wall of the annular groove and the minimum radial distance between the operating clearance and the outer peripheral wall of the annular groove are D, the minimum radial distance between two adjacent operating clearances is E, and the maximum axial displacement of the impeller is S; D≥4A, E≥2D, B≥S, C≥2B.

2. The centrifugal pump port ring sealing structure according to claim 1, characterized in that: The pump body mouth ring cover ring, the pump body mouth ring ring sheet, and the pump body mouth ring gasket are coaxially arranged and fit in pairs; the impeller mouth ring cover ring, the impeller mouth ring ring sheet, and the impeller mouth ring gasket are coaxially arranged and fit in pairs.

3. The centrifugal pump port ring sealing structure according to claim 1, wherein: The pump body mouth ring piece comprises a pump body mouth ring piece I and a pump body mouth ring piece II with different inner diameters, and the pump body mouth ring piece I and the pump body mouth ring piece II are arranged alternately.

4. The centrifugal pump port ring sealing structure according to claim 1, wherein: The impeller ring segments include an impeller ring segment I and an impeller ring segment II with different outer diameters, and the impeller ring segment I and the impeller ring segment II are arranged alternately.

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