Rotary shaft sealing structure for centrifugal pump and centrifugal pump

Abstract

The sealing structure is located on the periphery of a rotating shaft of the centrifugal pump and comprises a movable ring fixed to the rotating shaft and a static ring which is located on the periphery of the movable ring and does not rotate along with the rotating shaft. The movable ring and the static ring are provided with a plurality of annular paired sector teeth and concave grooves, and the plurality of pairs of sector teeth and concave grooves are arranged and distributed along the axial direction of the rotating shaft; the fan-shaped teeth comprise vertical parts fixed on the outer wall of the movable ring / the inner wall of the static ring and fan-shaped parts located at the top ends, the fan-shaped parts and the concave grooves are correspondingly arranged, and gaps are reserved between the fan-shaped parts and the corresponding concave grooves. According to the rotating shaft sealing structure, the sector tooth-concave groove structure is adopted, vortex dissipation in the cavity is increased, meanwhile, the sealing gap formed between the sector tooth and the concave groove is used for sealing fluid, the leakage amount of the high-pressure fluid is greatly reduced, and the sealing performance of the sealing structure under the high-pressure working condition is improved.

Description

Technical Field

[0001] The invention relates to the technical field of centrifugal pumps, in particular to a rotating shaft sealing structure for a centrifugal pump and a centrifugal pump. Background Art

[0002] A centrifugal pump is a pump that transports liquids by the centrifugal force generated by the rotation of the impeller. The centrifugal pump works by using the centrifugal motion of the liquid caused by the rotation of the impeller. Before starting the centrifugal pump, the pump casing and the suction pipe must be filled with liquid, and then the motor is started so that the pump shaft drives the impeller and the liquid to rotate at high speed. The liquid undergoes centrifugal motion and is thrown to the outer edge of the impeller, and flows into the centrifugal pump's water pressure pipeline through the flow channel of the volute pump casing.

[0003] After the centrifugal pump is started, the shaft rotates at high speed. If the seal is not proper, serious problems will occur. For example, the liquid in the pump may leak in large quantities from the gap between the shaft and the pump body. The liquid may be corrosive, toxic, or flammable and explosive. Leakage of corrosive liquids will corrode the equipment and shorten its life; leakage of toxic liquids will pollute the environment, threaten the health of personnel, and even cause poisoning; leakage of flammable and explosive liquids may explode and catch fire when encountering fire or static electricity, threatening the safety of personnel and property. In addition, poor sealing may also allow air to enter the pump body, destroy the pressure environment, cause air binding, affect the working efficiency and performance of the centrifugal pump, and interfere with the normal operation of the process. Therefore, during the operation of the centrifugal pump, the sealing of the shaft plays a vital role.

[0004] The existing centrifugal pump shaft seals usually use sleeve seals or mechanical seals. When the centrifugal pump is started and working normally, the shaft rotates at high speed. The sleeve seal will deteriorate due to friction and wear between the sleeve and the shaft, aging and deformation of the sealing material, and unstable sealing structure. Although the mechanical seal is precisely designed, it is prone to uneven wear of the sealing end face and deformation of the sealing ring under the centrifugal force, vibration, and complex fluid mechanics environment generated by high-speed rotation. These problems are particularly obvious, especially under high-pressure conditions, and large leakage is likely to occur, affecting the normal operation of the centrifugal pump and posing safety hazards. Therefore, it is urgent to design a centrifugal pump shaft sealing structure that can adapt to high-pressure conditions and improve the sealing performance of the centrifugal pump shaft. Summary of the invention

[0005] In view of the problem that the existing centrifugal pump shaft sealing structure is prone to large leakage under high-pressure working conditions, the present invention provides a centrifugal pump shaft sealing structure and a centrifugal pump. The centrifugal pump shaft sealing structure of the present invention adopts a sector tooth-concave groove structure to increase the eddy current dissipation inside the chamber, and at the same time uses the sealing gap formed between the sector tooth and the concave groove to seal the fluid, which greatly reduces the leakage of high-pressure fluid and improves the sealing performance of the sealing structure under high-pressure working conditions.

[0006] The technical solution adopted by the present invention is:

[0007] A centrifugal pump shaft sealing structure is located on the periphery of the centrifugal pump shaft, and includes a dynamic ring fixed on the shaft and a static ring located on the periphery of the dynamic ring and does not rotate with the shaft; the dynamic ring and the static ring are provided with a plurality of annular, paired sector teeth and concave grooves, and the plurality of pairs of sector teeth and concave grooves are arranged and distributed along the axial direction of the shaft; the sector teeth include a vertical portion fixed on the outer wall of the dynamic ring / inner wall of the static ring and a sector portion located at the top, the sector portions and the concave grooves are arranged correspondingly, and a gap is left between the sector portions and the corresponding concave grooves.

[0008] Furthermore, a plurality of the sector-shaped teeth are located on the dynamic ring or the static ring, and a plurality of concave grooves are located at corresponding positions of the static ring or the dynamic ring.

[0009] Furthermore, the number of the sector-shaped teeth is no less than 4.

[0010] Furthermore, the dynamic ring and the static ring are both provided with a plurality of sector-shaped teeth, and the sector-shaped teeth on the dynamic ring and the sector-shaped teeth on the static ring are distributed alternately.

[0011] Furthermore, the number of the sector-shaped teeth on the moving ring and the number of the sector-shaped teeth on the stationary ring are no less than 4.

[0012] Furthermore, the central angle of the sector portion is 70° to 120°, the radius of the sector portion is 0.5 to 0.9 mm, and the tooth thickness of the sector teeth is 0.25 to 0.6 mm;

[0013] The arc center of the sector portion and the arc center of the corresponding concave groove are the same point; the gap width between the sector portion and the corresponding concave groove is 0.05 to 0.2 mm;

[0014] The ring width of the sector teeth in the radial direction is 1.5 to 1.9 mm; the maximum depth of the concave groove in the radial direction is 0.05 to 0.6 mm; the tooth cavity length B between adjacent sector teeth in the axial direction is c 0.7~2mm;

[0015] A fillet is provided between the vertical portion and the fan-shaped portion, and between the outer wall of the moving ring and the inner wall of the stationary ring, and the radius of the fillet is 1 to 2.5 mm.

[0016] Furthermore, it also includes an anti-vibration structure, which includes an inner ring connected to the stationary ring, an outer ring located outside the inner ring, and a curved spring sheet disposed between the inner ring and the outer ring;

[0017] The inner ring and the outer ring have a first limit plate and a second limit plate at corresponding positions respectively. Both sides of the curved spring sheet in the circumferential direction of the rotating shaft abut against the first limit plate or the second limit plate, and the side surfaces of the first limit plate and the second limit plate at corresponding positions abut against each other.

[0018] Furthermore, the curved spring pieces are evenly distributed circumferentially between the inner ring and the outer ring; the number of the curved spring pieces is 6 to 12;

[0019] The cross-section of the curved spring piece is an arch, both ends of the curved spring piece are in contact with the inner ring / outer ring, and the middle part of the protrusion is in contact with the outer ring / inner ring.

[0020] Furthermore, the inner wall of the inner ring is provided with a boss, and the outer wall of the static ring is provided with a groove matching the boss;

[0021] The inner ring diameter d is 110% to 130% of D 轴 , the outer ring diameter D is 140%~160%D 轴 , the inner ring thickness t is 4% to 6% D 轴 , the inner ring boss width b is 12% to 18% D 轴 , where D 轴 is the diameter of the shaft.

[0022] A centrifugal pump comprises the rotating shaft sealing structure.

[0023] The beneficial effects of the present invention are:

[0024] The rotary shaft sealing structure of the present invention adopts a sector tooth-concave groove structure. Compared with the traditional straight or staggered teeth, under the condition of the same sealing length, the sector tooth structure increases the length of the sealing throttling gap and has a relatively small impact on the radial dimension. It can more effectively control the fluid flow and enhance the eddy current dissipation, and finally convert the pressure energy of the high-pressure fluid into heat energy for dissipation, thereby reducing leakage and improving the sealing efficiency, thereby avoiding the influence of leakage on the normal operation of the centrifugal pump.

[0025] When sector-shaped dynamic ring teeth and sector-shaped static ring teeth are used at the same time, that is, a sector-shaped tooth staggered structure is adopted, more cavities can be created in a limited space. The multiple sealing gaps formed can seal the fluid, which can further reduce the leakage of high-pressure fluid. This allows the shaft sealing structure to maintain low leakage under high-pressure conditions, and has broad application prospects.

[0026] The present invention can further reduce the influence of external vibration on the rotation of the rotor through the anti-vibration structure, improve the vibration resistance of the shaft sealing structure, avoid the increase of leakage due to excessive sealing gap, and thus improve the sealing effect. When plastic deformation occurs after long-term use and the elasticity disappears, it is only necessary to replace the curved spring piece at the corresponding position separately. Compared with the traditional anti-vibration structure using springs, the replacement is simpler and the replacement cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the "SS-CR-90" type shaft sealing structure in Example 1 of the present invention.

[0028] Figure 2 Schematic diagram of the "SS-CR-70" type shaft sealing structure in Example 2 of the present invention.

[0029] Figure 3 Schematic diagram of the "SS-CR-120" type shaft sealing structure in Example 3 of the present invention.

[0030] Figure 4 Schematic diagram of the "CS-SR-90" type shaft sealing structure in Example 4 of the present invention.

[0031] Figure 5 Schematic diagram of the "CS-SR-70" type shaft sealing structure in Example 5 of the present invention.

[0032] Figure 6 Schematic diagram of the "CS-SR-120" type shaft sealing structure in Example 6 of the present invention.

[0033] Figure 7 Schematic diagram of the "SS-SR-90" type shaft sealing structure in Example 7 of the present invention.

[0034] Figure 8 Schematic diagram of a rotating shaft sealing structure with an anti-vibration structure in Example 8 of the present invention, wherein (A) is a stereoscopic schematic diagram and (B) is a main view.

[0035] Fig. 9 Schematic diagram of radial cross section of the rotating shaft sealing structure with anti-vibration structure in Example 8 of the present invention.

[0036] Fig.10 Schematic diagram of relative parameters of the anti-vibration structure part in Example 8 of the present invention.

[0037] Fig.11 Schematic diagram of the straight-through shaft seal structure in comparative experiment 1.

[0038] Fig.12 Schematic diagram of the staggered shaft seal structure in comparative experiment 2.

[0039] Fig.13 It is a comparison diagram of leakage simulation of the sealing structure in Examples 1 to 7 of the present invention and Comparative Experiments 1 to 2.

[0040] Fig.14 (A) and (B) are respectively the flow field distribution diagrams inside the cavity of the "CS-SR-70" and "SS-SR-90" shaft sealing structures of the present invention.

[0041] In the figure, 1. static ring, 2. dynamic ring, 3. straight static ring teeth, 4. straight dynamic ring teeth, 5. fan-shaped dynamic ring teeth, 6. fan-shaped static ring teeth, 7. concave dynamic ring groove, 8. concave static ring groove, 91. inner ring, 911. first limit plate, 92. outer ring, 921. second limit plate, 93. curved spring sheet, 10. rotating shaft. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the specific implementation modes of the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0043] The centrifugal pump shaft sealing structure of the present invention is located outside the centrifugal pump shaft. Figure 1-7 As shown, the sealing structure includes a moving ring 2 fixed on the rotating shaft, and a stationary ring 1 located outside the moving ring 2 and not rotating with the rotating shaft; the moving ring 2 and the stationary ring 1 have a plurality of annular, paired sector teeth and concave grooves, and the plurality of pairs of sector teeth and concave grooves are arranged and distributed along the axial direction of the rotating shaft. The sector teeth include a vertical portion fixed on the outer wall of the moving ring 2 / the inner wall of the stationary ring 1 and a sector portion located at the top, the sector portion and the concave groove are arranged correspondingly, and a gap is left between the sector portion and the corresponding concave groove. In order to further study the leakage characteristics of the rotating shaft sealing structure for the centrifugal pump described in the present invention, 7 embodiments and 2 comparative tests are designed in the present invention. The main difference between the comparative test and the embodiment is that the sealing structure in the comparative test does not use the paired sector teeth and concave grooves in the present invention. The leakage of embodiments 1 to 7 and comparative tests 1 to 2 under different inlet and outlet pressure differences are simulated and calculated respectively to verify whether the rotating shaft sealing structure described in the present invention has better sealing performance.

[0044] In addition, it is also considered that the rotating machinery will inevitably produce mechanical vibration during high-speed rotation, which is easy to affect the normal operation of the shaft sealing structure and make the sealing gap size of the sealing structure unstable in the circumferential direction. Figure 8-9 An anti-vibration structure is also provided in the shaft sealing structure to reduce the leakage of the shaft sealing structure under high pressure conditions.

[0045] Example 1

[0046] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped stationary ring gear. Figure 1As shown, the shaft sealing structure includes a moving ring 2 fixed on the shaft, and a stationary ring 1 located outside the moving ring 2 and not rotating with the shaft. The moving ring 2 and the stationary ring 1 have a plurality of annular, paired sector teeth and concave grooves, and the plurality of pairs of sector teeth and concave grooves are arranged and distributed along the shaft axis. The sector teeth are sector stationary ring teeth 6 located on the inner wall of the stationary ring 1, and the concave grooves are concave stationary ring grooves 8 located on the outer wall of the moving ring 2. The number of sector stationary ring teeth 6 and concave moving ring grooves 7 are both 7. The sector stationary ring teeth 6 include a vertical portion fixed on the inner wall of the stationary ring 1 and a sector portion located at the top. The sector portion is matched with the concave moving ring groove 7 structure. The arc center of the sector portion and the arc center of the corresponding concave moving ring groove 7 are the same point, and a gap is left between the sector portion and the corresponding concave moving ring groove 7. The gap between the two forms a sealing gap. The sealing gap flow channel structure is in an arc shape, and the two ends of the flow channel are respectively connected to the chambers formed between the sector stationary ring teeth 6. During operation, the moving ring 2 rotates synchronously with the rotating shaft, and the stationary ring 1 does not rotate with the rotating shaft. A fillet is provided between the vertical portion on the sector-shaped stationary ring teeth 6 and the sector-shaped portion and the inner wall of the stationary ring 1, and the fillet radius is 2 mm.

[0047] In this embodiment, the central angle α of the sector portion is 90°. In order to distinguish different combination structures, the sector-shaped stationary ring gear 6 is abbreviated as SS, and the concave dynamic ring groove 7 is abbreviated as CR. The single-sided sector-shaped stationary ring gear shaft seal structure with the sector-shaped stationary ring gear 6 and the concave dynamic ring groove 7 and the sector portion having a central angle of 90° is abbreviated as the "SS-CR-90" type shaft seal structure. Figure 1 It is a partial schematic diagram of the "SS-CR-90" type shaft sealing structure described in this embodiment.

[0048] Sector-shaped stationary ring gear 6 ring root width H sf Defined as the distance from the upper surface of the cavity to the center of the fan-shaped part, the ring top width H sa Defined as the maximum distance from the center of the sector to the top of the tooth, the maximum depth H of the concave dynamic ring groove 7 in the radial direction r is the distance from the outer wall of the moving ring 2 to the bottom end of the concave moving ring groove 7 in the direction of the rotating shaft radius, and the tooth cavity length B c is the distance between two adjacent sector-shaped stationary ring teeth 6 in the axial direction of the shaft, and the tooth thickness B of the sector-shaped stationary ring teeth 6 s is the thickness of the fan-shaped stationary ring teeth 6 in the axial direction of the rotating shaft. In this embodiment, according to the aforementioned sealing structure, the number N1 of the fan-shaped stationary ring teeth 6 and the tooth thickness B of the fan-shaped stationary ring teeth 6 are determined. s , the center angle α of the sector-shaped stationary ring gear 6, the radius r of the sector-shaped stationary ring gear 6, the radius R of the concave dynamic ring groove 7, the number N2 of the concave dynamic ring groove 7 and the maximum depth H of the concave dynamic ring groove 7 r 、Fan-shaped stationary ring gear 6 ring root width H sf 、Fan-shaped static ring gear 6 ring top width H sa and tooth cavity length B cParameters, among which the sector-shaped stationary ring tooth 6 tooth thickness B s is the thickness of the vertical portion of the sector-shaped stationary ring gear 6. The specific values ​​of the design parameters determined by the "SS-CR-90" type shaft seal structure are shown in Table 3.

[0049] Table 3. Design parameters of the “SS-CR-90” shaft seal structure

[0050]

[0051] Combination Figure 1 As shown, the working principle of the rotary shaft sealing structure using fan-shaped dynamic and static ring gears of the present invention is as follows:

[0052] When the shaft is working normally, the high-pressure fluid will flow into the sealing cavity between the dynamic ring 2 and the static ring 1. First, a part of the high-pressure fluid will pass through the arc-shaped sealing gap between the fan-shaped static ring teeth 6 and the concave dynamic ring groove 7 wall. In this process, a part of the pressure energy contained in the high-pressure fluid will be converted into kinetic energy, and then converted into heat energy and dissipated under the action of friction. Then the remaining fluid is injected obliquely into the first cavity surrounded by the dynamic ring teeth 6 and the static ring teeth 7, and then impacts on the dynamic ring teeth and forms a vortex. Part of the kinetic energy is gradually converted into heat energy. Then, the remaining fluid is injected into the second cavity through the next sealing gap. In this process, the pressure energy of the fluid is dissipated again in the same way. The above process is repeated, and finally the pressure energy of the high-pressure fluid is completely converted into heat energy and dissipated, thereby achieving the goal of low leakage.

[0053] In this embodiment, ICEM CFD is used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-90" type shaft seal structure.

[0054] Example 2

[0055] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped stationary ring gear. The difference between the shaft seal structure described in this embodiment and the embodiment 1 is that the central angle α of the sector-shaped portion of the sector-shaped stationary ring gear 6 in this embodiment is 70°, and the other structural and dimensional parameters are consistent with those of the embodiment 1. For the purpose of distinction, the structure is hereinafter referred to as the "SS-CR-70" shaft seal structure. Figure 2 It is a partial schematic diagram of the "SS-CR-70" type shaft sealing structure described in this embodiment.

[0056] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13The relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-70" type shaft seal structure.

[0057] Example 3

[0058] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped stationary ring gear. The difference between the shaft seal structure described in this embodiment and the embodiment 1 is that the central angle α of the sector-shaped portion of the sector-shaped stationary ring gear 6 in this embodiment is 120°, and the other structural and dimensional parameters are consistent with those of the embodiment 1. For the purpose of distinction, the structure is hereinafter referred to as the "SS-CR-120" shaft seal structure. Figure 3 A partial schematic diagram of the "SS-CR-120" type shaft sealing structure described in this embodiment.

[0059] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-120" type shaft seal structure.

[0060] Example 4

[0061] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped dynamic ring tooth, and the shaft seal structure includes a dynamic ring 2 fixed on the shaft and rotating synchronously with the shaft, and a stationary ring 1 located outside the dynamic ring 2 and not rotating with the shaft, and the dynamic ring 2 and the stationary ring 1 have a plurality of annular, paired sector-shaped teeth and concave grooves, and the plurality of pairs of sector-shaped teeth and concave grooves are arranged and distributed along the shaft axis. The sector-shaped teeth are sector-shaped dynamic ring teeth 5 located on the outer wall of the dynamic ring 2, and the concave grooves are concave stationary ring grooves 8 located on the inner wall of the stationary ring 2, and the number of sector-shaped dynamic ring teeth 5 and concave stationary ring grooves 8 are both 7. The fan-shaped moving ring tooth 5 includes a vertical portion fixed on the outer wall of the moving ring 2 and a fan-shaped portion at the top. The fan-shaped portion cooperates with the concave static ring groove 8 structure. The arc center of the fan-shaped portion on the fan-shaped moving ring tooth 5 and the arc center of the corresponding concave static ring groove 8 are the same point, and there is a gap between the fan-shaped portion and the corresponding concave groove. The gap between the two forms a sealing gap. The sealing gap flow channel structure is in an arc shape, and the two ends of the flow channel are respectively connected to the chamber formed between the fan-shaped moving ring teeth 5. During operation, the moving ring 2 rotates synchronously with the rotating shaft, and the static ring 1 does not rotate with the rotating shaft. In this embodiment, a fillet is set between the vertical portion on the fan-shaped moving ring tooth 5 and the fan-shaped portion and the outer wall of the moving ring 2, and the fillet radius is 2mm.

[0062] In this embodiment, the central angle α of the sector portion is 90°. In order to distinguish different combination structures, the concave stationary ring groove 8 is abbreviated as CS, and the sector-shaped dynamic ring gear 5 is abbreviated as SR. The shaft sealing structure of the single-sided sector-shaped dynamic ring gear with the concave stationary ring groove 8 and the sector-shaped dynamic ring gear 5 and the central angle of the sector portion being 90° is abbreviated as the "CS-SR-90" shaft sealing structure. Figure 4 It is a partial schematic diagram of the "CS-SR-90" type shaft sealing structure described in this embodiment.

[0063] In this embodiment, according to the aforementioned sealing structure, the number N2 of the sector-shaped moving ring teeth 5 and the tooth thickness B of the sector-shaped moving ring teeth 5 are determined. r , the center angle α of the sector-shaped dynamic ring gear 5, the radius r of the sector-shaped dynamic ring gear 5, the radius R of the concave static ring groove 8, the number N1 of the concave static ring groove 8, the maximum depth H of the concave static ring groove 8 in the radial direction s 、Fan-shaped moving ring gear 5 ring root width H rf 、Fan-shaped moving ring gear 5 Ring top width H ra and tooth cavity length B c Parameters, the specific values ​​of the design parameters determined by the "CS-SR-90" shaft seal structure are shown in Table 4.

[0064] Table 4. Design parameters of the “CS-SR-90” shaft seal structure

[0065]

[0066] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-90" shaft seal structure.

[0067] Example 5

[0068] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped dynamic ring gear. The difference between the shaft seal structure described in this embodiment and the embodiment 4 is that the central angle α of the sector-shaped dynamic ring gear 5 is set to 70°, and the other structural and dimensional parameters are consistent with those of the embodiment 4. For the purpose of distinction, the structure is hereinafter referred to as the "CS-SR-70" shaft seal structure. Figure 5 A partial schematic diagram of the "CS-SR-70" type shaft sealing structure described in this embodiment.

[0069] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13The relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-70" type shaft seal structure.

[0070] Example 6

[0071] The shaft seal structure described in this embodiment is a shaft seal structure using a single-sided sector-shaped dynamic ring gear. The difference between the shaft seal structure described in this embodiment and the embodiment 4 is that the central angle α of the sector-shaped dynamic ring gear 5 is set to 120°, and the other structural and dimensional parameters are consistent with those of the embodiment 4. For the purpose of distinction, the structure is hereinafter referred to as the "CS-SR-120" shaft seal structure. Figure 6 A partial schematic diagram of the "CS-SR-120" type shaft sealing structure described in this embodiment.

[0072] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-120" shaft seal structure.

[0073] Example 7

[0074] The rotating shaft sealing structure described in this embodiment is a rotating shaft sealing structure that adopts a staggered arrangement of fan-shaped dynamic and static ring teeth, and the rotating shaft sealing structure includes a dynamic ring 2 fixed on the rotating shaft and rotating synchronously with the rotating shaft, and a static ring 1 located outside the dynamic ring 2 and not rotating with the rotating shaft. The dynamic ring 2 and the static ring 1 have a plurality of annular and paired fan-shaped teeth and concave grooves, and the plurality of pairs of fan-shaped teeth and concave grooves are arranged and distributed along the axial direction of the rotating shaft. The fan-shaped teeth are fan-shaped dynamic ring teeth 5 located on the outer wall of the dynamic ring 2 and fan-shaped static ring teeth 6 located on the inner wall of the static ring 2, and the concave grooves are concave static ring grooves 8 located on the inner wall of the static ring 2 and concave dynamic ring grooves 7 located on the outer wall of the dynamic ring 2. The fan-shaped dynamic ring teeth 5 and the fan-shaped static ring teeth 6 are staggered, and the number of the fan-shaped dynamic ring teeth 5 and the number of the concave static ring grooves 8 are both 6. The fan-shaped moving ring gear 5 / fan-shaped stationary ring gear 6 includes a vertical portion fixed on the outer wall of the moving ring 2 / the inner wall of the stationary ring 1 and a fan-shaped portion located at the top. The fan-shaped portion on the fan-shaped moving ring gear 5 / the fan-shaped stationary ring gear 6 matches the concave stationary ring groove 8 / the concave moving ring groove 7. The arc center of the fan-shaped portion on the fan-shaped moving ring gear 5 and the arc center of the corresponding concave stationary ring groove 8 are the same point, and the arc center of the fan-shaped portion on the fan-shaped stationary ring gear 6 and the arc center of the concave moving ring groove 7 are the same point. A gap is left between the fan-shaped portion and the corresponding concave groove, and the gap between the two forms a sealing gap, and the sealing gap flow channel structure presents an arc shape. During operation, the moving ring 2 rotates synchronously with the rotating shaft, and the stationary ring 1 does not rotate with the rotating shaft. In this embodiment, fillets are provided between the vertical portion on the fan-shaped moving ring gear 5 and the fan-shaped portion, the outer wall of the moving ring 2, and between the vertical portion on the fan-shaped stationary ring gear 6 and the fan-shaped portion, and the inner wall of the stationary ring 1, and the fillet radius is 2mm.

[0075] The difference between this embodiment and embodiments 1 and 4 is that in this embodiment, fan-shaped dynamic ring teeth 5 and fan-shaped static ring teeth 6 are provided at the same time, and the fan-shaped dynamic ring teeth 5 and the fan-shaped static ring teeth 6 are arranged alternately, so that the original large cavity can be divided into two small cavities, and compared with the previous two embodiments, the flow channel of this embodiment is more tortuous, has more cavities, and has a better dissipation effect on the fluid.

[0076] In this embodiment, the central angle of the sector of the sector-shaped stationary ring gear 6 and the sector-shaped dynamic ring gear 5 is 90°. In order to distinguish different combination structures, the sector-shaped stationary ring gear 6 is abbreviated as SS, and the sector-shaped dynamic ring gear 5 is abbreviated as SR. The rotating shaft sealing structure with staggered arrangement of sector-shaped dynamic and stationary ring teeth, which is provided with sector-shaped stationary ring gear 6 and sector-shaped dynamic ring gear 5 and the central angle of the sector of both sectors is 90°, is abbreviated as "SS-SR-90" type rotating shaft sealing structure. Figure 7 It is a partial schematic diagram of the "SS-SR-90" type shaft sealing structure described in this embodiment.

[0077] In this embodiment, according to the aforementioned sealing structure, the number N1 of the fan-shaped static ring teeth 6, the number N2 of the fan-shaped dynamic ring teeth 5, the center angle α1 of the fan-shaped static ring teeth 6, the center angle α2 of the fan-shaped dynamic ring teeth 5, the root width H of the fan-shaped static ring teeth 6 are determined. sf 、Fan-shaped moving ring gear 5 ring root width H rf 、Fan-shaped static ring gear 6 ring top width H sa 、Fan-shaped moving ring gear 5 Ring top width H ra 、Fan-shaped moving ring gear 5 tooth thickness B r 、Sector-shaped stationary ring gear 6 tooth thickness B s , the radius r of the sector-shaped dynamic ring tooth 5 and the sector-shaped static ring tooth 6, the arc radius R of the concave dynamic ring groove 7 and the concave static ring groove 8, the tooth cavity length B c Parameters, where the tooth cavity length B in this embodiment c is the distance between adjacent sector-shaped dynamic ring teeth 5 and sector-shaped stationary ring teeth 6 in the axial direction of the rotating shaft. The specific values ​​of various design parameters determined by the "SS-SR-90" type rotating shaft seal structure are shown in Table 5.

[0078] Table 5. Design parameters of the “SS-SR-90” shaft seal structure

[0079]

[0080]

[0081] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed through FLUENT. The leakage amount under different inlet and outlet pressure differences is simulated and calculated. Fig.13 The relationship curve between leakage Q and pressure difference Δp of the "SS-SR-90" shaft seal structure.

[0082] Example 8

[0083] In order to further improve the sealing performance of the shaft sealing structure, an anti-vibration structure is designed on the shaft sealing structure of the present invention. Figure 8-10 As shown, the anti-vibration structure includes an inner ring 91 connected to the stationary ring 1, an outer ring 92 installed on the outer periphery of the inner ring 91, and a curved spring piece 93 arranged between the inner ring 91 and the outer ring 92. The corresponding positions on the inner ring 91 and the outer ring 92 are respectively provided with a first limiting plate 911 and a second limiting plate 921. Both sides of the curved spring piece 93 in the circumferential direction of the rotating shaft 10 abut against the first limiting plate 911 or the second limiting plate 921, and the first limiting plate 911 or the second limiting plate 921 is used to limit the curved spring piece 93. The side surfaces of the first limiting plate 911 and the second limiting plate 921 at the corresponding positions abut against each other, so that the inner ring 91 and the outer ring 92 can be mutually limited by the first limiting plate 911 and the second limiting plate 921. In this embodiment, the cross-sectional shape of the curved spring piece 93 is an arch. The curved spring piece 93 is located between the two first limit plates 911. A tooth-shaped groove is formed between the two first limit plates 911. The two ends of the curved spring piece 93 are in contact with the inner ring 91, and the middle part of the protrusion is in contact with the outer ring 92. The outer sides of the two first limit plates 911 are respectively in contact with a second limit plate 921. The curved spring piece 93 is evenly distributed circumferentially between the inner ring 91 and the outer ring 92. The inner wall of the inner ring 91 is provided with a boss, and the outer wall of the stationary ring 1 is provided with a groove matching the boss. The inner ring 91 is connected to the stationary ring 1 through the boss and the groove to limit the circumferential direction. The outer ring 92 is directly connected to the external frame, and the connection method can be defined by oneself, such as key connection, screw connection, and pin connection.

[0084] Therefore, when the shaft 10 moves at high speed and generates relatively large mechanical vibration, the curved spring piece 93 is compressed to produce a buffering effect. The radial displacement of the static ring 1 of the shaft seal caused by external vibration is reduced, and the influence of increased leakage and reduced sealing performance due to excessive sealing gap is avoided. When plastic deformation occurs after long-term use and the elasticity disappears, it is only necessary to replace the curved spring piece 93 at the corresponding position. Compared with the traditional anti-vibration structure using springs, replacement is simpler and the replacement cost is lower.

[0085] In this embodiment, the thickness of the curved spring piece 93 is 0.4 mm, the length is not less than 9 mm, and the width is set according to the axial length of the shaft seal. In addition, curved spring pieces 93 of different thicknesses can be used according to specific needs. The number of curved spring pieces 93 in the circumferential direction is 6 to 12. In this embodiment, the number of curved spring pieces 93 in the circumferential direction is 10. The height of the boss on the inner surface of the inner ring 91 is 3% of the minor diameter d of the inner ring 91, and the matching tolerance with the groove is 0.05 mm. The angle of the same side of the toothed groove on the outer surface of the inner ring 91 relative to the center of the inner ring is 10°, the angle of the opposite side surface relative to the center of the inner ring 91 is 14.5°, and the height is 6% of the minor diameter d of the inner ring 91. The angle of the same side of the toothed groove on the inner surface of the outer ring 92 relative to the center of the outer ring is 15.5°, the angle of the opposite side surface relative to the center of the inner ring is 20°, and the height is 6% of the minor diameter d of the inner ring 91, and the relative parameters of each determined part are shown in Table 6, and the schematic diagram of the relative parameters of the high vibration resistance structure part is shown in Fig.10 shown.

[0086] Table 6. Some relative design parameters of high vibration resistance structure (Note: all relative to the diameter D of the shaft 10 轴 , the diameter of the rotating shaft used in this patent is 41mm)

[0087] Inner ring diameter d 122％ Outer ring path D 151％ Inner ring thickness t 4.9％ Inner ring boss width b 14.6％

[0088] Example 9

[0089] A centrifugal pump comprises a shaft sealing structure as described in any one of embodiments 1-8.

[0090] Comparative experiment 1

[0091] This comparative experiment adopts a common straight-through shaft seal structure, which is different from Example 1 in that: this comparative experiment does not use sector teeth and concave grooves, but uses straight teeth. Fig.11 As shown, the straight-through shaft sealing structure includes a dynamic ring 2 fixed on the shaft (not shown in the figure), and a static ring 1 located outside the dynamic ring 2 and does not rotate with the shaft. The inner wall of the static ring 1 has a plurality of straight static ring teeth 3 arranged and distributed along the axial direction of the shaft and in a ring shape. When working, the dynamic ring 2 rotates synchronously with the shaft, and the static ring 1 does not rotate with the shaft.

[0092] In this comparative test, the number N1 of the straight and static ring teeth 3 is 7, and the sealing gap C between the straight and static ring teeth 3 and the outer wall of the dynamic ring 2 is r Take 0.1mm, straight static ring gear 3 ring width H s Take 1.4mm, straight static ring gear 3 tooth thickness B s Take 0.3mm, the tooth cavity length B between two adjacent straight static ring teeth 3 c Taking 1.7mm, the design parameters of the straight-through shaft seal structure are shown in Table 1.

[0093] Table 1. Design parameters of straight-through shaft seal structure

[0094] <![CDATA[Number of stationary ring teeth N1 (pcs)]]> 7 <![CDATA[Sealing gap C r (mm)]]> 0.1 <![CDATA[Width H of the stationary ring gear ring s (mm)]]> 1.4 <![CDATA[Thickness B of the stationary ring teeth s (mm)]]> 0.3 <![CDATA[Tooth cavity length B c (mm)]]> 1.7

[0095] In this comparative test, ICEM CFD was used for meshing, and numerical simulation was performed through FLUENT. The leakage under different inlet and outlet pressure differences was simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the straight-through shaft seal structure.

[0096] Comparative experiment 2

[0097] The difference between this comparative experiment and comparative experiment 1 is: Fig.12 As shown, a plurality of annular direct-acting ring teeth 4 are arranged on the outer wall of the moving ring 2. The size of the direct-acting ring teeth 4 is the same as that of the direct-static ring teeth 3, and the direct-static ring teeth 3 and the direct-acting ring teeth 4 are arranged alternately. The rest of the structure is consistent with that of comparative experiment 1.

[0098] In this comparative experiment, the number N2 of the direct-acting ring teeth 4 is 6, and the width H of the direct-acting ring teeth 4 is r Take 1.4, direct-acting ring gear 4 tooth thickness B r Take 0.3, the distance C between the linear ring gear 4 and the wall of the adjacent linear and static ring gears 3 on both sides s Take 0.7, at this time, the distance between the direct-acting ring gear 4 and the adjacent direct-static ring gear 3 on both sides is equal, and the other size parameters are consistent with the comparative experiment 1. The design parameters of the staggered shaft seal structure are shown in Table 2.

[0099] Table 2. Design parameters of staggered shaft seal structure

[0100] <![CDATA[Number of teeth of the moving ring N2 (pcs)]]> 6 <![CDATA[Width H of the driving ring gear r (mm)]]> 1.4 <![CDATA[Thickness B of the driving ring gear tooth r (mm)]]> 0.3 <![CDATA[Spacing C s (mm)]]> 0.7

[0101] In this comparative test, ICEM CFD was used for meshing, and numerical simulation was performed through FLUENT. The leakage under different inlet and outlet pressure differences was simulated and calculated. Fig.13 The relationship curve between the leakage Q and the pressure difference Δp of the staggered shaft seal structure.

[0102] Sealing performance test: In the present invention, ICEM CFD is used to divide the meshes of Examples 1 to 7 and Comparative Experiments 1 to 2, and numerical simulation is performed by Fluent. The leakage under different inlet and outlet pressure differences is simulated and calculated, and the following results are obtained: Fig.13The leakage simulation comparison diagram of the rotary shaft sealing structure described in comparative experiments 1 to 2 and embodiments 1 to 7 is shown. The performance of the rotary shaft sealing structure described in embodiments 1 to 6 is compared with the straight-through rotary shaft seal in comparative experiment 1, and the sealing structure described in embodiment 7 is compared with the staggered rotary shaft seal in comparative experiment 2. Fig.13 It is clearly observed that the leakage of the fan-shaped shaft seal structure of Examples 1 to 6 using single-sided fan-shaped teeth distribution is always lower than that of the straight-through shaft seal in Comparative Experiment 1 under various pressure difference conditions, and the leakage of the fan-shaped shaft seal structure of Example 7 using staggered fan-shaped teeth distribution is always lower than that of the staggered shaft seal in Comparative Experiment 2 under various pressure difference conditions.

[0103] Compared with the straight-through shaft seal in comparative experiment 1, the leakage of the single-sided sector-shaped shaft seal structure of the present invention can be reduced by up to 36.64%. Compared with the staggered shaft seal in comparative experiment 2, the leakage of the "SS-SR-90" shaft seal structure of the present invention can be reduced by up to 17.67%. It can be seen that the shaft seal structure of the present invention using sector-shaped dynamic-static ring teeth shows more excellent sealing performance under the same working conditions and achieves the goal of low leakage.

[0104] Moreover, according to Fig.13 The simulation results also show that as the central angle of the sector decreases, the corresponding leakage gradually decreases. According to the flow field diagram analysis, a smaller angle can make the vortex structure generated inside larger, and the dissipation of the fluid kinetic energy is better. Therefore, the sealing performance of the "SS-CR-70" shaft sealing structure is better than other shaft sealing structures.

[0105] Furthermore, the flow field distribution inside the cavity of the "CS-SR-70" and "SS-SR-90" shaft seal structures was analyzed, and the results were obtained. Fig.14 The flow field distribution inside the cavity is shown in Figure 1. Fig.14 (A) and (B) are the flow field distribution diagrams inside the cavity of the "CS-SR-70" and "SS-SR-90" shaft seal structures, respectively. Fig.14 It can be observed that complete vortices are formed inside the cavity. The "SS-SR-90" divides the original tooth cavity into two tooth cavities through the staggered structure. The flow path is more tortuous, and three vortices are formed in the two tooth cavities. Fig.14 In (B), two large vortices 1 and 2, and a small vortex 3, can further increase the dissipation of fluid energy and achieve the goal of reducing leakage.

[0106] The examples are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A centrifugal pump shaft sealing structure, characterized in that: Located on the periphery of the rotating shaft of the centrifugal pump, it comprises a moving ring (2) fixed on the rotating shaft, and a stationary ring (1) located on the periphery of the moving ring (2) and not rotating with the rotating shaft; the moving ring (2) and the stationary ring (1) are provided with a plurality of annular, paired sector teeth and concave grooves, and the plurality of pairs of sector teeth and concave grooves are arranged and distributed along the axial direction of the rotating shaft; the sector teeth comprise a vertical portion fixed on the outer wall of the moving ring (2) / the inner wall of the stationary ring (1) and a sector portion located at the top, the sector portions and the concave grooves are arranged correspondingly, and a gap is left between the sector portions and the corresponding concave grooves.

2. The centrifugal pump shaft sealing structure according to claim 1, characterized in that: A plurality of the sector-shaped teeth are located on the moving ring (2) or the stationary ring (1), and a plurality of the concave grooves are located at corresponding positions of the stationary ring (1) or the moving ring (2).

3. The centrifugal pump shaft sealing structure according to claim 2, characterized in that: The number of the sector teeth is no less than 4.

4. The centrifugal pump shaft sealing structure according to claim 1, characterized in that: Both the moving ring (2) and the stationary ring (1) are provided with a plurality of sector-shaped teeth, and the sector-shaped teeth on the moving ring (2) and the sector-shaped teeth on the stationary ring (1) are distributed in an alternating manner.

5. The centrifugal pump shaft sealing structure according to claim 4, characterized in that: The number of the sector-shaped teeth on the moving ring (2) and the number of the sector-shaped teeth on the stationary ring (1) are both no less than 4.

6. The centrifugal pump shaft sealing structure according to claim 1, characterized in that: The central angle of the sector portion is 70° to 120°, the radius of the sector portion is 0.5 to 0.9 mm; the tooth thickness of the sector teeth is 0.25 to 0.6 mm; The arc center of the sector portion and the arc center of the corresponding concave groove are the same point; the gap width between the sector portion and the corresponding concave groove is 0.05 to 0.2 mm; The ring width of the sector teeth in the radial direction is 1.5 to 1.9 mm; the maximum depth of the concave groove in the radial direction is 0.05 to 0.6 mm; the tooth cavity length B between adjacent sector teeth in the axial direction is c 0.7~2mm; A fillet is provided between the vertical portion and the fan-shaped portion, the outer wall of the moving ring (2) and the inner wall of the stationary ring (1), and the fillet radius is 1 to 2.5 mm.

7. The centrifugal pump shaft sealing structure according to claim 1, characterized in that: It also includes an anti-vibration structure, which includes an inner ring (91) connected to the stationary ring (1), an outer ring (92) located outside the inner ring (91), and a curved spring sheet (93) arranged between the inner ring (91) and the outer ring (92); A first limiting plate (911) and a second limiting plate (921) are respectively provided at corresponding positions on the inner ring (91) and the outer ring (92); both sides of the curved spring sheet (93) in the circumferential direction of the rotating shaft abut against the first limiting plate (911) or the second limiting plate (921); and the side surfaces of the first limiting plate (911) and the second limiting plate (921) at corresponding positions abut against each other.

8. The centrifugal pump shaft sealing structure according to claim 7, characterized in that: The curved spring pieces (93) are evenly distributed in the circumferential direction between the inner ring (91) and the outer ring (92); the number of the curved spring pieces (93) is 6 to 12; The cross-section of the curved spring piece (93) is an arch, and both ends of the curved spring piece (93) are in contact with the inner ring (91) / outer ring (92), and the middle part of the protrusion is in contact with the outer ring (92) / inner ring (91).

9. The centrifugal pump shaft sealing structure according to claim 7, characterized in that: The inner wall of the inner ring (91) is provided with a boss, and the outer wall of the stationary ring (1) is provided with a groove matching the boss; The inner ring (91) has a minor diameter d of 110% to 130% D 轴 , the outer ring (92) diameter D is 140% to 160% D 轴 The thickness t of the inner ring (91) is 4% to 6% D 轴 The inner ring (91) boss width b is 12% to 18% D 轴 , where D 轴 is the diameter of the shaft.

10. A centrifugal pump, characterized in that: The invention comprises the rotating shaft sealing structure according to any one of claims 1 to 9.

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