A rotating shaft sealing structure for a centrifugal pump and a centrifugal pump

Abstract

The application discloses a rotating shaft sealing structure for a centrifugal pump and the centrifugal pump, and the sealing structure is located at the periphery of the rotating shaft of the centrifugal pump and comprises a dynamic ring fixed on the rotating shaft and a static ring located at the periphery of the dynamic ring and not rotating with the rotating shaft; the dynamic ring and the static ring are provided with a plurality of annular and 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 part fixed on the outer wall of the dynamic ring / the inner wall of the static ring and a sector part located at the top end, the sector part and the concave groove are correspondingly arranged, and a gap is left between the sector part and the corresponding concave groove. The rotating shaft sealing structure adopts the sector tooth-concave groove structure, increases the eddy current dissipation inside the chamber, simultaneously seals the fluid by using the sealing gap formed between the sector tooth and the concave groove, greatly reduces the leakage of high-pressure fluid, and improves the sealing performance of the sealing structure under high-pressure working conditions.

Description

TECHNICAL FIELD

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

[0002] A centrifugal pump refers to a pump that relies on centrifugal force generated by rotation of an impeller to transport liquid. The centrifugal pump works by utilizing the rotation of an impeller to cause liquid to undergo centrifugal motion. Before starting, the pump casing and the suction pipe must be filled with liquid. Then, the motor is started to make the pump shaft drive 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 then flows into the pressure pipe of the centrifugal pump through the flow channel of the volute pump casing.

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

[0004] The existing sealing of the rotating shaft of the centrifugal pump usually adopts shaft sleeve sealing or mechanical sealing. When the centrifugal pump is started and normally works, the rotating shaft rotates at high speed. The shaft sleeve sealing may be deteriorated due to reasons such as friction and wear between the shaft sleeve and the rotating shaft, aging and deformation of the sealing material, and unstable sealing structure. The mechanical sealing is designed to be precise, but under the action of centrifugal force, vibration and complex fluid mechanics environment generated by high-speed rotation, problems such as uneven wear of the sealing end face and deformation of the sealing ring may occur. Especially under high pressure working conditions, these problems are particularly obvious, and large leakage may easily occur, affecting the normal work of the centrifugal pump and existing safety hazards. Therefore, it is urgent to design a centrifugal pump rotating shaft sealing structure that can adapt to high pressure working conditions and improve the sealing performance of the centrifugal pump rotating shaft. SUMMARY

[0005] In view of the problem that the existing centrifugal pump rotating shaft sealing structure is prone to large leakage under high pressure working conditions, the present application provides a rotating shaft sealing structure for a centrifugal pump and the centrifugal pump. The rotating shaft sealing structure for the centrifugal pump adopts a fan-shaped tooth-recessed groove structure to increase the vortex dissipation inside the chamber, and at the same time, the sealing gap formed between the fan-shaped tooth and the recessed groove is used to seal the fluid, greatly reducing the leakage of high pressure fluid and improving the sealing performance of the sealing structure under high pressure working conditions.

[0006] The technical scheme adopted by the present application is as follows:

[0007] A rotating shaft sealing structure for centrifugal pump is located outside the rotating shaft of the centrifugal pump, comprising a dynamic ring fixed on the rotating shaft, and a static ring located outside the dynamic ring and not rotating with the rotating shaft; the dynamic ring and the static ring 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 comprise a vertical part fixed on the outer wall of the dynamic ring / the inner wall of the static ring and a fan-shaped part located at the top end, and the fan-shaped part and the concave groove are correspondingly arranged and a gap is left between the fan-shaped part and the corresponding concave groove.

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

[0009] Further, the number of the fan-shaped teeth is not less than 4.

[0010] Further, the dynamic ring and the static ring each have a plurality of fan-shaped teeth, and the fan-shaped teeth on the dynamic ring and the fan-shaped teeth on the static ring are staggered.

[0011] Further, the number of the fan-shaped teeth on the dynamic ring and the number of the fan-shaped teeth on the static ring are each not less than 4.

[0012] Further, the central angle of the fan-shaped part is 70°-120°, and the radius of the fan-shaped part is 0.5-0.9 mm; the tooth thickness of the fan-shaped tooth is 0.25-0.6 mm.

[0013] The arc center of the fan-shaped part and the arc center of the corresponding concave groove are the same point; the gap width between the fan-shaped part and the corresponding concave groove is 0.05-0.2 mm.

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

[0015] A fillet is arranged between the vertical part, the fan-shaped part, and the outer wall of the dynamic ring / the inner wall of the static ring, and the radius of the fillet is 1-2.5 mm.

[0016] Further, it further comprises an anti-vibration structure, the anti-vibration structure comprising an inner ring connected with the static ring, an outer ring located outside the inner ring, and a curved spring sheet arranged between the inner ring and the outer ring.

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

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

[0019] The cross-sectional shape of the curved spring piece is arched, the two 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] Further, 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 matched with the boss;

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

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

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

[0024] The rotating shaft sealing structure in the present application adopts a fan-shaped tooth-concave groove structure. Compared with the traditional linear or staggered teeth, under the condition of the same sealing length, the length of the sealing throttle gap is increased through the fan-shaped tooth structure, and the influence on the radial dimension is relatively small, which can more effectively control the fluid flow and enhance the vortex dissipation, finally converting the pressure energy of the high-pressure fluid into heat energy dissipation, thereby reducing leakage and improving sealing efficiency, and further avoiding the influence of leakage on the normal operation of the centrifugal pump.

[0025] When the fan-shaped dynamic ring teeth and the fan-shaped static ring teeth are used at the same time, that is, the fan-shaped tooth staggered structure is used, more cavities can be manufactured in a limited space, the multiple sealing gaps formed can seal the fluid, which can further reduce the leakage amount of the high-pressure fluid, so that the rotating shaft sealing structure can still maintain a low leakage amount under high-pressure working conditions, and has a broad application prospect.

[0026] The anti-vibration structure can further reduce the influence of external vibration on the rotation of the rotor, improve the anti-vibration property of the rotating shaft sealing structure, avoid the increase of leakage amount caused by the too large sealing gap, and further improve the sealing effect. When plastic deformation occurs after long-term use, the elastic property disappears, and only the corresponding position curved spring piece needs to be replaced, which is simpler and has lower replacement cost compared with the traditional spring anti-vibration structure. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of the "SS-CR-90" type rotating shaft sealing structure in Example 1 of the present application.

[0028] Figure 2 Figure 1 is a schematic view of a rotating shaft sealing structure of "SS-CR-70" type in the embodiment 2 of the present application.

[0029] Figure 3 Figure 2 is a schematic view of a rotating shaft sealing structure of "SS-CR-120" type in the embodiment 3 of the present application.

[0030] Figure 4 Figure 3 is a schematic view of a rotating shaft sealing structure of "CS-SR-90" type in the embodiment 4 of the present application.

[0031] Figure 5 Figure 4 is a schematic view of a rotating shaft sealing structure of "CS-SR-70" type in the embodiment 5 of the present application.

[0032] Figure 6 Figure 5 is a schematic view of a rotating shaft sealing structure of "CS-SR-120" type in the embodiment 6 of the present application.

[0033] Figure 7 Figure 6 is a schematic view of a rotating shaft sealing structure of "SS-SR-90" type in the embodiment 7 of the present application.

[0034] Figure 8 Figure 7 is a schematic view of a rotating shaft sealing structure with anti-vibration structure in the embodiment 8 of the present application, wherein (A) is a perspective view and (B) is a front view.

[0035] Figure 9 Figure 8 is a schematic view of a radial section of the rotating shaft sealing structure with anti-vibration structure in the embodiment 8 of the present application.

[0036] Figure 10 Figure 9 is a schematic view of relative parameters of the anti-vibration structure in the embodiment 8 of the present application.

[0037] Figure 11 Figure 10 is a schematic view of a straight-through type rotating shaft sealing structure in the comparative experiment 1.

[0038] Figure 12 Figure 11 is a schematic view of an interleaved type rotating shaft sealing structure in the comparative experiment 2.

[0039] Figure 13 Figure 12 is a simulation comparison chart of the leakage amount of the sealing structures in the embodiments 1-7 and the comparative experiments 1-2 of the present application.

[0040] Figure 14 (A) and (B) are respectively the internal flow field distribution charts of the "CS-SR-70" type and "SS-SR-90" type rotating shaft sealing structures in the present application.

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

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

[0043] The rotating shaft sealing structure for centrifugal pump according to the application is located at the periphery of the rotating shaft of the centrifugal pump. Figures 1-7 As shown in the figure, the sealing structure comprises a dynamic ring 2 fixed on the rotating shaft and a static ring 1 located at the periphery of the dynamic ring 2 and not rotating with the rotating shaft; the dynamic ring 2 and the static ring 1 are provided with a plurality of pairs of fan-shaped teeth and concave grooves in a ring shape; 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 comprise a vertical part fixed on the outer wall of the dynamic ring 2 / the inner wall of the static ring 1 and a fan-shaped part at the top end, and the fan-shaped part and the concave groove are arranged correspondingly and a gap is left between the fan-shaped part and the corresponding concave groove. In order to further study the leakage characteristics of the rotating shaft sealing structure for centrifugal pump according to the application, seven embodiments and two comparative tests are designed in the application. The main difference between the comparative tests and the embodiments is that the sealing structure in the comparative tests does not adopt the pairs of fan-shaped teeth and concave grooves according to the application. The leakage amounts of the embodiments 1-7 and the comparative tests 1-2 under different inlet and outlet pressure differences are simulated and calculated respectively, so as to verify whether the rotating shaft sealing structure according to the application has better sealing performance.

[0044] In addition, it is also considered that the rotating machinery will inevitably produce mechanical vibration in high-speed rotation, which is easy to affect the normal work of the rotating shaft sealing structure, so that the size of the sealing gap of the sealing structure is unstable in the circumferential direction. Figures 8-9 Therefore, an anti-vibration structure is also arranged in the rotating shaft sealing structure to reduce the leakage amount of the rotating shaft sealing structure under high pressure working condition.

[0045] Embodiment 1

[0046] The rotating shaft sealing structure according to the embodiment adopts a single-sided fan-shaped static ring tooth, as shown in the figure. Figure 1As shown, the rotating shaft sealing structure includes a dynamic ring 2 fixed on the rotating shaft, a static ring 1 located on the periphery of the dynamic ring 2 and not rotating with the rotating shaft, and a plurality of ring-shaped and paired sector teeth and concave grooves on the dynamic ring 2 and the static ring 1, 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 are sector static ring teeth 6 located on the inner wall of the static ring 1, and the concave grooves are concave dynamic ring grooves 7 located on the outer wall of the dynamic ring 2. The number of sector static ring teeth 6 and concave dynamic ring grooves 7 is 7. The sector static ring teeth 6 include a vertical part fixed on the inner wall of the static ring 1 and a sector part at the top end. The sector part is matched with the structure of the concave dynamic ring groove 7. The center of the arc line of the sector part and the center of the arc line on the corresponding concave dynamic ring groove 7 are the same point. There is a gap between the sector part and the corresponding concave dynamic ring groove 7. The gap between the two forms a sealing gap. The structure of the flow channel of the sealing gap is arc-shaped. The two ends of the flow channel are respectively connected with the cavity formed between the sector static ring teeth 6. In operation, the dynamic ring 2 rotates synchronously with the rotating shaft, and the static ring 1 does not rotate with the rotating shaft. The vertical part and the sector part on the sector static ring teeth 6 and the inner wall of the static ring 1 are provided with a fillet. The radius of the fillet is 2 mm.

[0047] In this embodiment, the central angle α of the sector part is 90°. In order to distinguish different combination structures, the sector static ring teeth 6 are simply referred to as SS, and the concave dynamic ring groove 7 is simply referred to as CR. Therefore, the single-sided sector static ring teeth rotating shaft sealing structure provided with the sector static ring teeth 6 and the concave dynamic ring groove 7 and having a central angle of 90° of the sector part is simply referred to as “SS-CR-90” type rotating shaft sealing structure. Figure 1 It is a partial schematic view of the “SS-CR-90” type rotating shaft sealing structure described in this embodiment.

[0048] The ring root width H of the sector static ring teeth 6 sf The ring top width H of the sector static ring teeth 6 is defined as the distance from the upper surface of the cavity to the center of the sector part. sa The maximum depth H of the concave dynamic ring groove 7 in the radial direction is defined as the maximum distance from the center of the sector part to the top of the tooth. r The tooth cavity length B is the distance from the outer wall of the dynamic ring 2 to the bottom end of the concave dynamic ring groove 7 in the radial direction of the rotating shaft. c The tooth thickness B of the sector static ring teeth 6 is the distance between two adjacent sector static ring teeth 6 in the axial direction of the rotating shaft. s The thickness B of the sector static ring teeth 6 in the axial direction of the rotating shaft is determined according to the sealing structure described above. In this embodiment, the number N1 of sector static ring teeth 6, the tooth thickness B of sector static ring teeth 6, the central angle α of sector static ring teeth 6, the radius r of the sector part of sector static ring teeth 6, the radius R of the concave dynamic ring groove 7, the number N2 of concave dynamic ring grooves 7, and the maximum depth H of the concave dynamic ring groove 7 are determined. s r The ring root width H of the sector static ring teeth 6 sf The ring top width H of the sector static ring teeth 6 sa And the tooth cavity length B c ​Parameters, wherein the tooth thickness B of the sector-shaped static ring tooth 6 s The thickness of the vertical part of the sector-shaped static ring tooth 6, the specific numerical values of the design parameters of the "SS-CR-90" type shaft sealing structure are shown in Table 3.

[0049] Table 3. Design parameters of the "SS-CR-90" type shaft sealing structure

[0050]

[0051] In combination Figure 1 The working principle of the shaft sealing structure with the sector-shaped dynamic and static ring teeth according to the present application is shown in the following:

[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 sector-shaped static ring tooth 6 and the wall surface of the concave dynamic ring groove 7. In this process, a part of the pressure energy contained in the high-pressure fluid will be converted into kinetic energy, and then into heat energy under the action of friction and dissipated. Then the remaining fluid obliquely enters the first cavity surrounded by the dynamic ring tooth 6 and the static ring tooth 7 and impacts on the dynamic ring tooth and forms a vortex, a part of the kinetic energy gradually converts into heat energy. Then, only the remaining fluid enters the second cavity through the next sealing gap. In this process, the pressure energy of the fluid is dissipated in the same way. Through the above-mentioned process, 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 carried out by fluent. The leakage under different inlet and outlet pressure differences is simulated and calculated, and the relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-90" type shaft sealing structure in the above-mentioned formula is obtained. Figure 13

[0054] Example 2

[0055] The shaft sealing structure described in this embodiment is a shaft sealing structure with single-sided sector-shaped static ring teeth. The difference between the shaft sealing structure described in this embodiment and example 1 is that the central angle α of the sector-shaped part of the sector-shaped static ring tooth 6 is 70° in this embodiment, and the rest of the structure and size parameters are consistent with example 1. For distinction, the structure is referred to as "SS-CR-70" type shaft sealing structure, Figure 2 is a partial schematic view 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 carried out by fluent. The leakage under different inlet and outlet pressure differences is simulated and calculated, and the relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-70" type shaft sealing structure in the above-mentioned formula is obtained. Figure 13 ​The relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-120" type shaft seal structure in the figure.

[0057] Example 3

[0058] The shaft seal structure described in the present example is a shaft seal structure using single-sided fan-shaped static ring teeth. The difference between the shaft seal structure described in the present example and that of Example 1 is that the central angle a of the fan-shaped part of the fan-shaped static ring teeth 6 in the present example is 120°, and the rest of the structure and size parameters are consistent with those of Example 1. For the sake of distinction, the structure is hereinafter referred to as "SS-CR-120" type shaft seal structure. Figure 3 The partial schematic view of the "SS-CR-120" type shaft seal structure described in the present example.

[0059] In the present example, ICEM CFD is also used for meshing, and numerical simulation is carried out by fluent. The leakage under different inlet and outlet pressure differences is simulated and calculated to obtain Figure 13 The relationship curve between the leakage Q and the pressure difference Δp of the "SS-CR-120" type shaft seal structure in the figure.

[0060] Example 4

[0061] The shaft seal structure described in the present example is a shaft seal structure using single-sided fan-shaped dynamic ring teeth. The shaft seal structure comprises a dynamic ring 2 fixed on the shaft and rotating synchronously with the shaft, and a static ring 1 located on the periphery of the dynamic ring 2 and not rotating with the shaft. The dynamic ring 2 and the static ring 1 have a plurality of ring-shaped and paired fan-shaped teeth and concave grooves. A plurality of pairs of fan-shaped teeth and concave grooves are arranged and distributed along the axial direction of the shaft. The fan-shaped teeth are fan-shaped dynamic ring teeth 5 located on the outer wall of the dynamic ring 2, and the concave grooves are concave static ring grooves 8 located on the inner wall of the static ring 2. The number of fan-shaped dynamic ring teeth 5 and concave static ring grooves 8 is 7. The fan-shaped dynamic ring teeth 5 comprise a vertical part fixed on the outer wall of the dynamic ring 2 and a fan-shaped part at the top end. The fan-shaped part cooperates with the structure of the concave static ring groove 8. The arc center of the fan-shaped part on the fan-shaped dynamic ring tooth 5 and the arc center of the corresponding concave static ring groove 8 are the same point. There is a gap between the fan-shaped part and the corresponding concave groove, and the gap forms a sealing gap. The flow channel structure of the sealing gap presents an arc shape, and the flow channel is connected with the cavity formed between the fan-shaped dynamic ring tooth 5 at both ends. When working, the dynamic ring 2 rotates synchronously with the shaft, and the static ring 1 does not rotate with the shaft. In the present example, a fillet is provided between the vertical part and the fan-shaped part of the fan-shaped dynamic ring tooth 5 and the outer wall of the dynamic ring 2. The radius of the fillet is 2 mm.

[0062] In the present embodiment, the central angle a of the sector is 90°. In order to distinguish different combination structures, the concave static ring groove 8 is referred to as CS, and the sector dynamic ring tooth 5 is referred to as SR. Therefore, the single-sided sector dynamic ring tooth shaft sealing structure provided with the concave static ring groove 8 and the sector dynamic ring tooth 5 and having a sector central angle of 90° is referred to as a "CS-SR-90" type shaft sealing structure. Figure 4 A partial view of the "CS-SR-90" type shaft sealing structure described in the present embodiment is shown in FIG. 4.

[0063] In the present embodiment, the number N2 of sector dynamic ring teeth 5, the tooth thickness B of the sector dynamic ring tooth 5, the central angle a of the sector dynamic ring tooth 5, the sector radius r of the sector dynamic ring tooth 5, the radius R of the concave static ring groove 8, the number N1 of concave static ring grooves 8, the maximum depth H of the concave static ring groove 8 in the radial direction, the ring root width H of the sector dynamic ring tooth 5, the ring top width H of the sector dynamic ring tooth 5, and the tooth cavity length B are determined according to the sealing structure described above. r s rf ra c The specific values of the design parameters of the "CS-SR-90" type shaft sealing structure are shown in Table 4.

[0064] Table 4. Design parameters of the "CS-SR-90" type shaft sealing structure

[0065]

[0066] In the present embodiment, ICEM CFD is also used for meshing, numerical simulation is performed by fluent, and the leakage under different inlet and outlet pressure differences is simulated and calculated to obtain the relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-90" type shaft sealing structure in FIG. 6. Figure 13

[0067] Embodiment 5

[0068] The shaft sealing structure described in the present embodiment is a single-sided sector dynamic ring tooth shaft sealing structure. The difference between the shaft sealing structure and the shaft sealing structure of Embodiment 4 is that the central angle a of the sector dynamic ring tooth 5 is 70°, and the remaining structure and size parameters are consistent with those of Embodiment 4. In order to distinguish, the structure is referred to as a "CS-SR-70" type shaft sealing structure below. Figure 5 A partial view of the "CS-SR-70" type shaft sealing structure described in the present embodiment is shown in FIG. 5.

[0069] In the present embodiment, ICEM CFD is also used for meshing, numerical simulation is performed by fluent, and the leakage under different inlet and outlet pressure differences is simulated and calculated to obtain the relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-70" type shaft sealing structure in FIG. 7. Figure 13 ​​​​​The relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-120" type shaft seal structure in the figure.

[0070] Example 6

[0071] The shaft seal structure described in this embodiment is a shaft seal structure using single-side sector-shaped dynamic ring teeth, which is different from that of Example 4 in that the central angle α of the sector-shaped dynamic ring teeth 5 is 120°, and the rest of the structure and size parameters are consistent with those of Example 4. For distinction, the structure is referred to as "CS-SR-120" type shaft seal structure below. Figure 6 The partial schematic view of the "CS-SR-120" type shaft seal structure described in this embodiment.

[0072] In this embodiment, ICEM CFD is also used for meshing, and numerical simulation is performed by fluent. The leakage under different inlet and outlet pressure differences is simulated and calculated to obtain Figure 13 The relationship curve between the leakage Q and the pressure difference Δp of the "CS-SR-120" type shaft seal structure in the figure.

[0073] Example 7

[0074] The shaft seal structure described in this embodiment is a shaft seal structure using sector-shaped dynamic and static ring teeth staggered arrangement, which includes a dynamic ring 2 fixed on the shaft and rotating synchronously with the shaft, and a static ring 1 located on the periphery of the dynamic ring 2 and not rotating with the shaft. The dynamic ring 2 and the static ring 1 have a plurality of pairs of sector-shaped teeth and concave grooves in a ring shape. A plurality of pairs of sector-shaped teeth and concave grooves are arranged and distributed along the axial direction of the shaft. The sector-shaped teeth are sector-shaped dynamic ring teeth 5 on the outer wall of the dynamic ring 2 and sector-shaped static ring teeth 6 on the inner wall of the static ring 2, and the concave grooves are concave static ring grooves 8 on the inner wall of the static ring 2 and concave dynamic ring grooves 7 on the outer wall of the dynamic ring 2. The sector-shaped dynamic ring teeth 5 and the sector-shaped static ring teeth 6 are staggered distributed, and the number of sector-shaped dynamic ring teeth 5 and sector-shaped static ring teeth 6 is 6. The sector-shaped dynamic ring teeth 5 / sector-shaped static ring teeth 6 include a vertical part fixed on the outer wall of the dynamic ring 2 / inner wall of the static ring 1 and a sector-shaped part at the top end. The sector-shaped part on the sector-shaped dynamic ring teeth 5 / sector-shaped static ring teeth 6 cooperates with the concave static ring groove 8 / concave dynamic ring groove 7. The arc center of the sector-shaped part on the sector-shaped dynamic ring teeth 5 and the arc center of the corresponding concave static ring groove 8 are the same point, and the arc center of the sector-shaped part on the sector-shaped static ring teeth 6 and the arc center of the concave dynamic ring groove 7 are the same point. There is a gap between the sector-shaped part and the corresponding concave groove, and the gap forms a sealing gap, and the structure of the sealing gap flow channel is arc-shaped. The dynamic ring 2 rotates synchronously with the shaft during operation, and the static ring 1 does not rotate with the shaft. In this embodiment, a fillet is provided between the vertical part and the sector-shaped part on the sector-shaped dynamic ring teeth 5, the outer wall of the dynamic ring 2, and between the vertical part and the sector-shaped part on the sector-shaped static ring teeth 6, the inner wall of the static ring 1. The radius of the fillet is 2mm.

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

[0076] In this embodiment, the central angle of the fan-shaped part of the fan-shaped static ring teeth 6 and the fan-shaped dynamic ring teeth 5 is 90°. In order to distinguish different combination structures, the fan-shaped static ring teeth 6 are referred to as SS, and the fan-shaped dynamic ring teeth 5 are referred to as SR. Therefore, the shaft sealing structure with the fan-shaped dynamic ring teeth 6 and the fan-shaped dynamic ring teeth 5 arranged alternately and the central angle of the fan-shaped part of both being 90° is referred to as the "SS-SR-90" type shaft sealing structure. Figure 7 It is a partial schematic view 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 central angle α1 of the fan-shaped static ring teeth 6, the central angle α2 of the fan-shaped dynamic ring teeth 5, the ring root width H sf of the fan-shaped dynamic ring teeth 5, the ring top width H rf of the fan-shaped static ring teeth 6, the ring top width H sa of the fan-shaped dynamic ring teeth 5, the tooth thickness B ra of the fan-shaped dynamic ring teeth 5, the tooth thickness B r of the fan-shaped static ring teeth 6, the radius r of the fan-shaped part of the fan-shaped dynamic ring teeth 5 and the fan-shaped static ring teeth 6, the arc radius R of the concave dynamic ring groove 7 and the concave static ring groove 8, and the tooth cavity length B c are determined. c The tooth cavity length B 轴 in this embodiment is the distance between the adjacent fan-shaped dynamic ring teeth 5 and the fan-shaped static ring teeth 6 in the axial direction of the shaft. The specific values of the design parameters of the "SS-SR-90" type shaft sealing structure are shown in Table 5.

[0078] Table 5. Design parameters of the "SS-SR-90" type shaft sealing structure

[0079]

[0080]

[0081] In this embodiment, ICEM CFD is also used for meshing, numerical simulation is carried out by fluent, and the leakage under different inlet and outlet pressure differences is simulated and calculated to obtain the relationship curve between the leakage Q and the pressure difference Δp of the "SS-SR-90" type shaft sealing structure in Figure 13 .

[0082] Embodiment 8

[0083] In order to further improve the sealing performance of the rotating shaft sealing structure, an anti-vibration structure is designed on the rotating shaft sealing structure of the present application, which is combined with the sealing structure of the present application Figures 8-10 As shown in the figure, the anti-vibration structure comprises an inner ring 91 connected with the static ring 1, an outer ring 92 installed on the periphery of the inner ring 91, and a curved spring sheet 93 arranged between the inner ring 91 and the outer ring 92. The inner ring 91 and the outer ring 92 have a first limiting plate 911 and a second limiting plate 921 at the corresponding positions respectively, and the curved spring sheet 93 abuts against the first limiting plate 911 or the second limiting plate 921 on both sides in the circumferential direction of the rotating shaft 10, and the first limiting plate 911 or the second limiting plate 921 is used to limit the curved spring sheet 93. The first limiting plate 911 and the second limiting plate 921 at the corresponding positions abut against each other on the side, so that the inner ring 91 and the outer ring 92 can be limited by each other between the first limiting plate 911 and the second limiting plate 921. In this embodiment, the cross-sectional shape of the curved spring sheet 93 is arc-shaped, the curved spring sheet 93 is located between the two first limiting plates 911, the tooth-shaped groove is formed between the two first limiting plates 911, the two ends of the curved spring sheet 93 are in contact with the inner ring 91, the protruding middle part is in contact with the outer ring 92, and each of the two first limiting plates 911 abuts against one second limiting plate 921 on the outside. The curved spring sheet 93 is uniformly distributed between the inner ring 91 and the outer ring 92 in the circumferential direction. The inner wall of the inner ring 91 is provided with a boss, and the outer wall of the static ring 1 is provided with a groove matched with the boss, and the inner ring 91 is connected with the static ring 1 through the boss and the groove to limit the circumferential direction. The outer ring 92 is directly connected with the external rack, and the connection mode can be defined by itself, such as key connection, screw connection, and pin connection.

[0084] Therefore, when the rotating shaft 10 moves at high speed and generates relatively large mechanical vibration, the curved spring sheet 93 is compressed to produce a buffering effect. The displacement of the static ring 1 of the rotating shaft sealing in the radial direction caused by external vibration is reduced, and the influence of the increase of leakage amount and the reduction of sealing performance caused by the too large sealing gap is avoided. When plastic deformation occurs after long-term use, the elasticity disappears, and only the corresponding position of the curved spring sheet 93 needs to be replaced. Compared with the traditional anti-vibration structure using springs, the replacement is simpler and the replacement cost is lower.

[0085] In the embodiment, the curved spring sheet 93 has a thickness of 0.4 mm, a length of not less than 9 mm, and a width determined according to the axial length of the shaft seal. In addition, curved spring sheets 93 with different thicknesses can be used according to specific requirements. The number of curved spring sheets 93 in the circumferential direction is 6-12, and in the embodiment, the number of curved spring sheets 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 small diameter d of the inner ring 91, and the mating tolerance of the groove is 0.05 mm. The tooth-shaped groove on the outer surface of the inner ring 91 has a same-side surface with an angle of 10° with respect to the center angle of the inner ring 91, and an opposite-side surface with an angle of 14.5° with respect to the center angle of the inner ring 91, and a height of 6% of the small diameter d of the inner ring 91. The tooth-shaped groove on the inner surface of the outer ring 92 has a same-side surface with an angle of 15.5° with respect to the center angle of the outer ring 92, and an opposite-side surface with an angle of 20° with respect to the center angle of the inner ring 91, and a height of 6% of the small diameter d of the inner ring 91. The relative parameters of the determined parts are shown in Table 6, and the relative parameters of the high-vibration-resistant structure are shown in Figure 10 .

[0086] Table 6. Relative design parameters of parts of the high-vibration-resistant structure (Note: all are relative to the diameter D of the shaft 10, which is 41 mm in the patent) 轴 .

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

[0088] Embodiment 9

[0089] A centrifugal pump comprising the shaft seal structure of any one of embodiments 1-8.

[0090] Comparative Experiment 1

[0091] The common straight-through shaft seal structure is used in the comparative experiment, and the difference from embodiment 1 is that the fan-shaped teeth and the concave groove are not used in the comparative experiment, but straight teeth are used. Specifically, as shown in Figure 11 , the straight-through shaft seal structure comprises a dynamic ring 2 fixed on a shaft (not shown in the figure) and a static ring 1 located on the periphery of the dynamic ring 2 and not rotating with the shaft. The inner wall of the static ring 1 has a plurality of annular straight static ring teeth 3 arranged in the axial direction of the shaft. During operation, the dynamic ring 2 rotates synchronously with the shaft, and the static ring 1 does not rotate with the shaft.

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

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

[0094] Static ring teeth number N1 (pcs.) 7 Sealing gap C r (mm) 0.1 Static ring tooth ring width H s (mm) 1.4 Static ring tooth thickness B s (mm) 0.3 Tooth cavity length B c (mm) 1.7

[0095] In this comparative experiment, ICEM CFD was used for mesh generation, and Fluent was used for numerical simulation. The leakage rate under different inlet and outlet pressure differentials was simulated and calculated. Figure 13 The relationship curve between leakage Q and pressure difference Δp in the straight-through type rotating shaft seal structure.

[0096] Comparative Experiment 2

[0097] The difference between this comparative experiment and Comparative Experiment 1 is that: [The following is a continuation of the previous sentence, but the translation is incomplete and requires further context.] Figure 12 As shown, several annular linear moving ring teeth 4 are arranged on the outer wall of the moving ring 2. The size of the linear moving ring teeth 4 is the same as that of the linear stationary ring teeth 3, and the linear stationary ring teeth 3 and the linear moving ring teeth 4 are arranged alternately. The rest of the structure is the same as that of the comparative experiment 1.

[0098] In this comparative experiment, the number of direct-acting ring teeth 4, N2, is 6, and the ring width of direct-acting ring teeth 4 is H. r Take 1.4, direct-acting ring gear with 4 teeth and thickness B r Take 0.3, the distance C between the walls of the direct-acting ring tooth 4 and the adjacent two-sided stationary ring teeth 3. s Taking a value of 0.7, the distance between the direct-acting ring tooth 4 and the adjacent stationary ring teeth 3 on both sides is equal, and the remaining dimensional parameters are consistent with those in 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] Number of moving ring teeth N2 (pieces) 6 H r (mm)]]> 1.4 B r (mm)]]> 0.3 Pitch C s (mm) 0.7

[0101] In this comparative experiment, ICEM CFD was used for mesh generation, and Fluent was used for numerical simulation. The leakage rate under different inlet and outlet pressure differentials was simulated and calculated. Figure 13 The relationship curve between leakage Q and pressure difference Δp in the staggered shaft seal structure.

[0102] Sealing performance test: In this invention, ICEM CFD was used for mesh generation in Examples 1-7 and Comparative Experiments 1-2, and numerical simulation was performed using Fluent. The leakage rate under different inlet and outlet pressure differences was simulated and calculated, and the results are as follows: Figure 13The leakage simulation comparison chart of the shaft seal structure described in the comparative experiments 1-2 and examples 1-7. The performance of the shaft seal structure described in examples 1-6 is compared with the straight-through type shaft seal in comparative experiment 1, and the performance of the shaft seal structure described in example 7 is compared with the staggered type shaft seal in comparative experiment 2. It can be observed from Figure 13 that the leakage of the fan-shaped shaft seal structure of examples 1-6 with single-sided fan-shaped tooth distribution is always lower than that of the straight-through type shaft seal in comparative experiment 1 under various pressure difference conditions, and the leakage of the fan-shaped shaft seal structure of example 7 with staggered fan-shaped tooth distribution is always lower than that of the staggered type shaft seal in comparative experiment 2 under various pressure difference conditions.

[0103] Compared with the straight-through type shaft seal in comparative experiment 1, the leakage of the single-sided fan-shaped tooth shaft seal structure of the application can be reduced by at most 36.64%. Compared with the staggered type shaft seal in comparative experiment 2, the leakage of the “SS-SR-90” type shaft seal structure of the application can be reduced by at most 17.67%. It can be seen that the shaft seal structure with fan-shaped dynamic and static ring teeth of the application exhibits more excellent sealing performance under the same working conditions, and achieves the goal of low leakage.

[0104] Moreover, according to the simulation results of Figure 13 it can be seen that as the angle of the center angle of the fan-shaped part decreases, the corresponding leakage also gradually decreases. According to the flow field analysis, a small angle can make the internal vortex structure larger, and the dissipation of fluid kinetic energy is better. Therefore, the sealing performance of the “SS-CR-70” type shaft seal structure is more excellent than that of other shaft seal structures.

[0105] Further, the flow field distribution inside the cavity of the “CS-SR-70” type and “SS-SR-90” type shaft seal structures is analyzed, and the flow field distribution chart inside the cavity is obtained as shown in Figure 14 Figure 14 (A) and (B) are the flow field distribution charts inside the cavity of the “CS-SR-70” type and “SS-SR-90” type shaft seal structures, respectively. It can be observed from Figure 14 that complete vortices are formed inside the cavities. The “SS-SR-90” divides the original one tooth cavity into two tooth cavities through the staggered structure, the flow channel is more tortuous, and three vortices are formed in the two tooth cavities. In Figure 14 (B), two large vortices 1 and 2 and one small vortex 3 are formed, which can further increase the dissipation of fluid energy and achieve the goal of reducing the leakage.

[0106] ​The above examples are preferred embodiments of the present application, but the present application is not limited to the above embodiments, and any obvious improvements, replacements or modifications made by those skilled in the art without departing from the spirit of the present application shall fall within the scope of protection of the present application.

Claims

1. A rotating shaft seal structure for a centrifugal pump, characterized by: The centrifugal pump shaft is located at the periphery of the shaft, including the dynamic ring (2) fixed on the shaft, the static ring (1) located at the periphery of the dynamic ring (2) and not rotating with the shaft; the dynamic ring (2) and the static ring (1) have a plurality of annular and paired sector teeth and concave grooves, and a plurality of pairs of sector teeth and concave grooves are arranged and distributed along the shaft axis; the sector teeth include a vertical part fixed on the outer wall of the dynamic ring (2) / the inner wall of the static ring (1) and a sector part at the top end, and the sector part and the concave groove are correspondingly arranged and have a gap between the sector part and the corresponding concave groove.

2. The rotating shaft seal structure for a centrifugal pump according to claim 1, characterized by, A plurality of sector teeth are located on the dynamic ring (2) or the static ring (1), and a plurality of concave grooves are located on the corresponding position of the static ring (1) or the dynamic ring (2).

3. The rotating shaft seal structure for a centrifugal pump according to claim 2, characterized by The number of sector teeth is not less than 4.

4. The rotating shaft seal structure for a centrifugal pump according to claim 1, characterized by The dynamic ring (2) and the static ring (1) each have a plurality of sector teeth, and the sector teeth on the dynamic ring (2) and the sector teeth on the static ring (1) are staggered.

5. The rotating shaft seal structure for a centrifugal pump according to claim 4, characterized by The number of sector teeth on the dynamic ring (2) and the number of sector teeth on the static ring (1) are each not less than 4.

6. The rotating shaft seal structure for a centrifugal pump according to claim 1, characterized by The central angle of the sector part is 70°-120°, and the radius of the sector part is 0.5-0.9 mm; the thickness of the sector tooth is 0.25-0.6 mm. The arc center of the sector part and the arc center of the corresponding concave groove are the same point; the gap width between the sector part and the corresponding concave groove is 0.05-0.2 mm. The ring width of the sector tooth in the radial direction is 1.5-1.9mm; the maximum depth of the concave groove in the radial direction is 0.05-0.6mm; the tooth cavity length B of the adjacent sector teeth in the axial direction is 0.7-2mm c . The vertical part, the sector part, and the outer wall of the dynamic ring (2) / the inner wall of the static ring (1) are provided with a fillet, and the radius of the fillet is 1-2.5 mm.

7. The rotating shaft seal structure for a centrifugal pump according to claim 1, characterized by It also includes an anti-vibration structure, which includes an inner ring (91) connected with the static ring (1), an outer ring (92) located at the periphery of the inner ring (91), and a curved spring sheet (93) arranged between the inner ring (91) and the outer ring (92). The corresponding positions of the inner ring (91) and the outer ring (92) respectively have first limiting plates (911) and second limiting plates (921), and the curved spring sheet (93) abuts against the first limiting plate (911) or the second limiting plate (921) on both sides in the circumferential direction of the shaft, and the side surfaces of the first limiting plate (911) and the second limiting plate (921) at the corresponding positions abut against each other.

8. The rotating shaft seal structure for a centrifugal pump according to claim 7, characterized by The curved spring sheet (93) is uniformly distributed between the inner ring (91) and the outer ring (92) in the circumferential direction; the number of the curved spring sheet (93) is 6-12. The cross-sectional shape of the curved spring sheet (93) is arched, the two ends of the curved spring sheet (93) contact the inner ring (91) / the outer ring (92), and the protruding middle part contacts the outer ring (92) / the inner ring (91).

9. The rotating shaft seal structure for a centrifugal pump according to claim 7, wherein The inner wall of the inner ring (91) is provided with a boss, and the outer wall of the static ring (1) is provided with a groove matched with the boss. The inner ring (91) has a small diameter d of 110% to 130% D 轴 The outer ring (92) has a large diameter D of 140% to 160% D 轴 The inner ring (91) has a thickness t of 4% to 6% D 轴 The inner ring (91) has a boss width b of 12% to 18% D 轴 where D 轴 is the diameter of the rotating shaft.

10. A centrifugal pump characterized by It includes the shaft sealing structure of any one of claims 1-9.

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