Spiral wear ring sealing structure of lead-bismuth pump

Abstract

The utility model discloses a spiral wear ring sealing structure of a lead-bismuth pump, which belongs to the technical field of fluid mechanical equipment and comprises a rotating impeller, and a hollow annular sealing structure is arranged between the outer edge of the rotating impeller and the inner wall of a pump casing to form a wear ring gap. Helical teeth are arranged on the outer wall face of the sealing structure, the tooth profile of the helical teeth forms a helical channel, the helical channel spirally ascends in the axial direction, the direction of the helical channel is opposite to the rotating direction of the impeller, and the three-dimensional distortion of the helical teeth has an inclination angle alpha in the radial direction. Due to the fact that the rotating direction of the spiral groove channel is opposite to that of the impeller, leakage flow has the tendency of being pushed reversely, leakage of gap fluid is hindered, hydraulic loss is reduced, efficiency is improved, certain reverse axial force can be possibly generated, axial force generated by other components is helped to be balanced, and the hydraulic stability of a pump set is improved.

Description

Technical Field

[0001] This utility model belongs to the field of fluid machinery equipment technology, and relates to a spiral port ring sealing structure for a lead-bismuth pump. Background Technology

[0002] In the operation of lead-bismuth pumps, the impeller ring seal structure is essential. It reduces wear, improves efficiency, and extends service life by minimizing direct contact between moving and stationary parts. However, ring clearance can cause some high-pressure fluid to leak back, interfering with the main flow and affecting the pump's stable operation. A reasonable ring clearance can balance leakage and wear, reducing leakage and maintaining efficient operation. For high-speed machinery, non-contact ring seals are typically used, utilizing fluid viscosity to reduce leakage. However, while flat and serrated seals are simple in structure, they suffer from drawbacks such as high leakage and poor sealing performance.

[0003] Chinese Patent Publication No. CN219711852U, Publication Date: September 19, 2023, discloses a Chinese patent entitled "A Maintenance Seal for a Lead-Bismuth Pump." The maintenance seal includes a base, a housing, eight working bellows (four of which are fixed to the base with bolts or similar fasteners), and one sealing bellows. The base has an air inlet connected to the working bellows. The working bellows are evenly spaced circumferentially around the rotor assembly. The sealing bellows are fitted onto the rotor assembly, with one end connected to the base and the other end connected to a sealing cover. The sealing bellows here use a serrated seal, which has drawbacks such as significant leakage at the joint and poor sealing performance. Utility Model Content

[0004] This invention provides a spiral inlet ring sealing structure for a lead-bismuth pump. By setting a spiral channel and an inclination angle, the leakage of the sealing gap is reduced, and the leakage flow tends to be pushed in the opposite direction, which hinders the leakage of fluid in the gap, thereby achieving a good sealing effect.

[0005] To achieve the above objectives, this utility model adopts the following technical solution: a spiral ring sealing structure for a lead-bismuth pump, comprising a rotating impeller, a hollow annular sealing structure between the outer edge of the rotating impeller and the inner wall of the pump casing, forming an annular gap; the outer wall surface of the sealing structure is provided with spiral teeth, the profile of the spiral teeth forming a spiral channel, the spiral channel spirally rising axially in the opposite direction to the impeller rotation direction, and the three-dimensional twist of the spiral teeth having an inclination angle α in the radial direction. Because the spiral channel rotates in the opposite direction to the impeller rotation direction, the leakage flow tends to be pushed in the opposite direction, hindering the leakage of interstitial fluid, reducing hydraulic loss, improving efficiency, and potentially generating a certain reverse axial force, helping to balance the axial forces generated by other components and improving the hydraulic stability of the pump unit.

[0006] Preferably, the sealing structure features five interconnected spiral channels evenly arranged along the axial direction. These spiral channels ascend in a spiral pattern along the axial direction, similar to a threaded structure. The spiral channels are three-dimensionally twisted, and their upper and lower surfaces (the lower surface here only represents the surface opposite to the upper surface and does not actually exist) are not radially stretched but rather have a certain inclination angle α. The multi-layered spiral channels create a multi-stage reverse pushing effect, further enhancing the obstruction of leakage flow, effectively reducing leakage, and simultaneously reducing energy loss caused by leakage, thereby improving pump operating efficiency.

[0007] Preferably, one longitudinal section of the helical teeth is a regular quadrilateral. The regular quadrilateral cross-section structure gives the helical teeth better structural stability when subjected to fluid pressure, effectively resisting deformation caused by fluid impact. At the same time, its regular geometry helps to optimize the flow state of the fluid in the helical channel, further reducing hydraulic losses.

[0008] Preferably, the width and height of the helical teeth are both 1 mm. This dimensional design ensures both the precision requirements of the helical teeth during machining and assembly, and sufficient space in the helical channels for fluid passage, thereby achieving good sealing performance and reverse pushing function. Furthermore, the smaller tooth width and height help reduce machining difficulty and cost.

[0009] Preferably, a ring gap is formed between the bottom of the spiral channel of the sealing structure and the annular inner wall of the sealing structure, thereby reducing the direct contact between the impeller and the pump casing; this is the ring gap. The spiral channel is designed to rise spirally along the positive z-axis, opposite to the impeller's rotation direction (clockwise when viewed from above). The spiral sealing structure then rises spirally in a right-hand direction. This not only causes the leakage flow to be pushed back, reducing the leakage amount, but also reduces vibration and noise caused by fluid dynamics to a certain extent.

[0010] Preferably, the width of the annular gap is 0.4 mm. Due to the impeller's rotation and pressurization, most of the liquid flowing through the inlet pipe is transported along the flow channel to the reverse guide vane 3 and then into the secondary impeller. The secondary impeller continues to drive the water flow, rotating and pressurizing it, and then transporting it to the forward guide vane, finally exiting from the outlet pipe. However, the liquid that has gained some energy from the impeller is not completely transported; a small portion leaks through the gap from the high-pressure side to the low-pressure side of the impeller inlet. The 0.4 mm annular gap width effectively reduces the leakage from the high-pressure side to the low-pressure side while ensuring that the impeller and pump casing do not directly contact each other. Simultaneously, this gap width balances sealing performance and pump operating efficiency, avoiding increased frictional losses due to an excessively small gap.

[0011] Preferably, the diameter of the annular inner wall of the sealing structure is 67 mm. Due to its unique spiral ring seal structure, it increases the frictional resistance and local friction of the leakage flow, thus hindering liquid leakage from the high-pressure side to the low-pressure side through the gap to a certain extent. This diameter matches the overall structure of the pump, ensuring good installation adaptability and sealing performance within the pump. Simultaneously, the 67 mm diameter provides sufficient space for the spiral channel, further enhancing its effect in impeding leakage flow.

[0012] Preferably, the sealing structure has a length of 11 mm. An 11 mm length provides sufficient axial extension space for the helical channel, thereby achieving a more effective reverse pushing action and leakage flow obstruction effect. At the same time, this length design ensures the installation stability of the sealing structure within the pump, avoiding structural instability or insufficient sealing performance due to being too long or too short.

[0013] Preferably, the perpendicular line between the apex of the helical tooth and the inner wall of the gap between the mouth rings is AB, and the tangent line of the helical tooth's twisted surface along the height direction passing through the apex is AC. A perpendicular line AB is drawn from point A on the octagonal curve of the upper surface of the helical sealing channel to the inner wall of the gap between the mouth rings, with the foot of the perpendicular being B; a tangent line AC is drawn from point A to the twisted surface of the helical channel along the height direction.

[0014] Preferably, the angle between AB and AC is an inclination angle α, where α is 10°. The twisting of the upper and lower surfaces of the spiral channel causes the fluid to rotate as it passes through the channel, which helps to remove impurities and particles from the sealing surface, extending the service life of the seal. The 10° inclination angle α allows the spiral teeth to form a reasonable twisting angle in the radial direction, further optimizing the fluid flow state within the spiral channel. This design not only enhances the reverse pushing effect on leakage flow but also causes the fluid to rotate as it passes through the channel, effectively removing impurities and particles from the sealing surface and extending the service life of the seal.

[0015] The beneficial effects of this invention are as follows: This invention provides a spiral ring sealing structure for a lead-bismuth pump, which minimizes impeller ring leakage and ensures the pump maintains high efficiency during multi-stage pressurization. The spiral channel spirals upwards along the axial direction, increasing frictional and local friction of the leakage flow, thereby reducing leakage in the sealing gap. Increasing the torsion of the spiral channel, creating a certain angle between its upper and lower surfaces, and ensuring the spiral channel rotates in the opposite direction to the impeller, forces the leakage flow to be pushed in the opposite direction, hindering leakage of fluid in the gap and thus achieving a good sealing effect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a lead-bismuth pump equipped with a sealing structure.

[0017] Figure 2This is a schematic diagram of the sealing structure of this utility model.

[0018] Figure 3 This is a schematic diagram of a sealed structure model.

[0019] Figure 4 for Figure 3 Enlarged view of point A.

[0020] Reference numerals in the attached drawings: 1. Inlet pipe; 2. Sealing structure; 3. Reverse guide vane; 4. Rotating impeller; 5. Inlet ring gap; 6. Inner wall of inlet ring gap; 7. Spiral channel; 8. Spiral tooth. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] During operation, the impeller ring seal structure 2 is essential for lead-bismuth pumps due to their complex internal structure and the positional relationship between rotating and stationary parts. The impeller ring gap 5 reduces direct contact between rotating and stationary parts, lowers wear, improves efficiency, and extends the service life of components. Fluid enters the impeller and is pressurized by its high-speed rotation. Due to the ring gap 5, some high-pressure fluid leaks back to the inlet through the gap at the impeller outlet, causing secondary flow interference with the main inlet flow and significantly impacting the efficient and stable operation of the lead-bismuth pump. Although the ring gap 5 inevitably leads to some fluid leakage, it also limits leakage. A reasonable ring gap 5 can balance the relationship between leakage and wear, minimizing leakage while preventing wear, thus maintaining the pump's efficient operation. For high-speed rotating machinery, the sealing structure 2 between rotating and stationary parts is generally a non-contact annular seal, which mainly utilizes the viscous effect of the fluid in the gap to cause frictional loss and reduce leakage. While familiar flat seals and sawtooth seals are simple in structure and easy to manufacture, they have disadvantages such as higher leakage and poorer sealing effect. This invention adjusts the impeller mouth ring sealing structure 2, rationally designs the gap size, reduces vibration and noise problems caused by the mouth ring gap 5, provides a better sealing effect, and enables the lead-bismuth pump to maintain good performance after long-term operation.

[0023] This invention provides a spiral ring seal structure 2 suitable for lead-bismuth pumps, which minimizes impeller ring leakage and ensures efficient operation of the pump during multi-stage pressurization. The number and size of the serrated grooves in the serrated seal ring are matched with the ring gap 5 and the sealing gap length. The serrated groove direction is reversed, spiraling upwards axially. This increases the frictional and local friction of the leakage flow, thereby reducing leakage in the sealing gap. Increasing the torsion of the spiral channel 7, creating a certain angle between its upper and lower surfaces, and ensuring the spiral channel 7 rotates in the opposite direction to the impeller, forces the leakage flow to be pushed in the opposite direction, hindering leakage of the gap fluid and achieving a good sealing effect.

[0024] like Figure 1 As shown, the spiral annular sealing structure 2 of this lead-bismuth pump is designed around the rotating impeller 4. A hollow annular sealing structure 2 is provided between the outer edge of the rotating impeller 4 and the inner wall of the pump casing, forming an annular gap 5. The sealing structure 2 is located at the top of the inlet pipe 1. This gap is a key area that needs to be controlled, because a small portion of the liquid that gains energy from the impeller will leak from the high-pressure side to the low-pressure side of the impeller inlet through this gap during transportation. The core design of this invention lies in controlling the leakage flow through this gap.

[0025] like Figure 3 As shown, the outer wall of the sealing structure 2 is provided with helical teeth 8, the tooth profile of which forms a helical channel 7. The helical channel 7 rises spirally along the axial direction, and its direction is opposite to the impeller rotation direction. When the impeller rotates, the liquid in the pump is thrown towards the pump casing under the action of centrifugal force. At this time, some liquid may leak through the gap 5 of the inlet ring. However, since the helical channel 7 rotates in the opposite direction to the impeller, the leakage flow tends to be pushed in the reverse direction when passing through the helical channel 7. This reverse pushing effect can effectively hinder the leakage of gap fluid, thereby reducing the leakage amount. At the same time, the three-dimensional twist of the helical teeth 8 has an inclination angle α in the radial direction. This design further optimizes the flow state of the fluid in the channel, which not only enhances the reverse pushing effect on the leakage flow, but also makes the fluid generate rotational motion when passing through the channel, which is beneficial to remove impurities and particles on the sealing surface and extend the service life of the seal.

[0026] like Figure 3As shown, five interconnected spiral channels 7 are uniformly arranged in the axial direction of the sealing structure 2. The core purpose of this innovative multi-layered spiral channel 7 design is to construct a multi-stage reverse-push system to significantly improve sealing performance. Specifically, when the leaking fluid passes through the first layer of spiral channels 7, it is subjected to a reverse-push force opposite to the leakage direction, which initially controls the leakage. Subsequently, the leaking fluid enters the second layer of spiral channels 7. During this process, the fluid is not only subjected to the reverse-push force again but also encounters additional flow resistance. This dual effect further reduces the leakage. Through this progressive principle, the synergistic work of the five layers of spiral channels 7 results in a significant cumulative enhancement of the obstruction effect on the leaking flow, thereby achieving effective control of the leakage. Furthermore, this multi-stage obstruction mechanism not only significantly reduces the leakage but also effectively reduces energy loss caused by leakage, which is of significant practical importance for improving the overall operating efficiency of the pump. From the perspective of fluid dynamics, this design cleverly utilizes the principle of kinetic and potential energy conversion of fluids, and achieves effective energy recovery and utilization through multi-stage reverse pushing action, thereby achieving the goal of energy saving and efficiency improvement.

[0027] like Figure 2 As shown, one longitudinal section of the helical tooth 8 is a regular square. The regular square cross-section structure has many advantages. In terms of withstanding fluid pressure, the regular square can evenly distribute the pressure, giving the helical tooth 8 better structural stability in complex fluid impact environments and effectively resisting deformation caused by fluid impact. From a fluid dynamics perspective, its regular geometry helps optimize the flow state of the fluid within the helical channel. When the fluid flows through the channel, the regular square helical tooth 8 can guide the fluid to flow smoothly, reducing turbulence and vortex generation, and further reducing hydraulic losses.

[0028] like Figure 2 As shown, the width and height of the helical teeth 8 are both 1 mm. This dimensional design was carefully considered. During machining and assembly, the 1 mm dimension ensures both the precision requirements of the helical teeth 8, making the fit between each helical tooth 8 tighter, and sufficient space in the helical channels for fluid passage. If the tooth width and height are too large, it will reduce the channel space, increase the resistance to fluid passage, and affect the pump performance; while if the dimensions are too small, it may not meet the requirements for structural strength and sealing effect. At the same time, the smaller tooth width and height help reduce machining difficulty and cost.

[0029] like Figure 2As shown, the width of the ring gap 5 is 0.4 mm. This width effectively reduces fluid leakage from the high-pressure side to the low-pressure side while ensuring that the impeller and pump casing do not come into direct contact. If the ring gap 5 is too wide, leakage will increase significantly, reducing pump efficiency; conversely, if the gap is too narrow, although leakage will decrease, frictional losses between the impeller and pump casing will increase, also affecting pump performance. The 0.4 mm ring gap 5 width balances sealing performance and pump operating efficiency. In practical applications, tests with different gap widths have shown that a 0.4 mm gap width provides the best overall pump performance, keeping leakage at a low level while maintaining frictional losses within an acceptable range.

[0030] like Figure 2 As shown, the diameter of the annular inner wall of the sealing structure 2 is 67mm. This diameter matches the overall structure of the pump, ensuring good installation adaptability of the sealing structure 2 within the pump. Simultaneously, the 67mm diameter provides sufficient space for the spiral channel 7, further enhancing its ability to impede leakage flow. If the diameter is too small, the space for the spiral channel 7 is limited, hindering fluid flow and reverse propulsion; while if the diameter is too large, the fit between the sealing structure 2 and the pump casing may be loose, affecting sealing performance. Through actual pump installation tests, the 67mm diameter allows the sealing structure 2 to be stably installed within the pump and exhibits excellent sealing performance during operation.

[0031] The sealing structure 2 has a length of 11 mm. This 11 mm length provides sufficient axial extension space for the spiral channel 7. Within this length range, the spiral channel 7 can fully utilize its reverse thrust and leakage flow obstruction effects. If the length is too short, the leakage flow may not be adequately subjected to the reverse thrust force, leading to increased leakage; while an excessively long length may increase the overall size and weight of the pump, as well as manufacturing costs. In actual operation, the 11 mm length of the sealing structure 2 effectively reduces leakage and ensures the pump's compact structure and economy.

[0032] like Figure 3 and Figure 4 As shown, Figure 4 As shown, point A is selected at a specific location on the upper surface edge curve of the spiral sealing channel. A perpendicular line AB is drawn from this point to the inner wall 6 of the mouth ring gap, with the foot of the perpendicular at B. Simultaneously, a tangent AC is drawn through point A to the twisted surface of the spiral channel along the height direction. The angle formed between AB and AC is the inclination angle α, with a value of 10°. This precisely designed 10° inclination angle α forms an optimized twist angle in the radial direction of the spiral teeth 8. This angle has been verified through fluid dynamics simulation and experiments, proving to be the optimal angle range. When the working fluid flows through the spiral channel 7, this specific inclination angle can effectively guide the fluid to generate a stable rotational motion.

[0033] First, from a fluid dynamics perspective, the centrifugal effect generated by rotational motion significantly enhances the reverse pushing effect on the leaking flow. This pushing effect intensifies with increasing fluid rotation speed, resulting in a more effective seal and further controlling leakage. Second, from a mechanical seal perspective, the rotational motion of the fluid creates a dynamic cleaning mechanism at the sealing interface. This mechanism continuously removes impurities and particles deposited on the sealing surface, preventing wear and blockage, thus extending the service life of the seal. Furthermore, this rotational motion improves the fluid flow state, making the fluid distribution within the sealing gap more uniform, reducing the generation of local eddies and turbulence, thereby reducing energy loss and improving the overall system efficiency. From an engineering application perspective, this design not only improves sealing performance but also enhances the reliability and stability of the system, possessing significant practical engineering value.

[0034] This invention relates to a spiral ring seal structure suitable for lead-bismuth pumps. Due to its unique spiral ring seal structure 2, it increases the frictional resistance and local friction of the leakage flow, thus hindering the leakage of liquid from the high-pressure side to the low-pressure side through the gap to a certain extent. The twisting of the upper and lower surfaces of the spiral channel 7 causes the fluid to rotate as it passes through the channel, which helps to remove impurities and particles from the sealing surface, extending the service life of the seal. Since the spiral channel 7 rotates in the opposite direction to the impeller, the leakage flow tends to be pushed in the opposite direction, hindering the leakage of fluid in the gap, reducing hydraulic losses, improving efficiency, and potentially generating a certain reverse axial force, which helps to balance the axial forces generated by other components, improving the hydraulic stability of the pump unit.

[0035] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this utility model.

Claims

1. A spiral inlet ring sealing structure for a lead-bismuth pump, comprising a rotating impeller, characterized in that, A hollow annular sealing structure is provided between the outer edge of the rotating impeller and the inner wall of the pump casing to form an annular gap; The outer wall of the sealing structure is provided with helical teeth. The profile of the helical teeth forms a helical channel. The helical channel rises spirally along the axial direction, opposite to the direction of impeller rotation. The three-dimensional twist of the helical teeth has an inclination angle α in the radial direction.

2. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 1, characterized in that, The sealing structure has five interconnected spiral channels evenly arranged along the axial direction.

3. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 1, characterized in that, The longitudinal section of one side of the helical tooth is a regular quadrilateral.

4. A spiral-shaped inlet ring sealing structure for a lead-bismuth pump according to claim 1 or 3, characterized in that, The tooth width and tooth height of the helical teeth are both 1 mm.

5. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 1, characterized in that, A ring gap is formed between the bottom of the spiral channel of the sealing structure and the annular inner wall of the sealing structure.

6. A spiral-shaped inlet ring sealing structure for a lead-bismuth pump according to claim 1 or 5, characterized in that, The width of the gap between the mouth rings is 0.4 mm.

7. A spiral-shaped inlet ring sealing structure for a lead-bismuth pump according to claim 1 or 5, characterized in that, The diameter of the annular inner wall of the sealing structure is 67 mm.

8. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 7, characterized in that, The length of the sealing structure is 11mm.

9. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 1, characterized in that, The perpendicular line between the apex of the helical tooth and the inner wall of the gap between the teeth is AB, and the tangent line of the twisted surface of the helical tooth along the height direction passing through the apex is AC.

10. The spiral inlet ring sealing structure for a lead-bismuth pump according to claim 9, characterized in that, The angle between AB and AC is the inclination angle α, where α is 10°.

Images