A method for manufacturing a double-tongue volute for a centrifugal pump and the double-tongue volute thereof.

Abstract

This invention discloses a manufacturing method for a double-tongue volute for centrifugal pumps and the double-tongue volute itself. The aim is to provide a method and a double-tongue volute for centrifugal pumps that improves efficiency and stability, optimizes internal flow, reduces energy consumption, reduces pulsation characteristics, and enhances reliability and comfort by suppressing undesirable flow phenomena. Key technical aspects include integrated blank preparation, preliminary quality inspection and finishing, tongue gap detection, cooling device, surface strengthening treatment of qualified products, residual stress detection, shot breakage rate detection, and performance testing. This allows for the timely detection of defective products, the repair of repairable products, and the ensuring of product quality, thus improving product reliability and stability. This invention is applicable to the field of centrifugal pump technology.

Description

Technical Field

[0001] This invention relates to the field of centrifugal pump technology, and more specifically, to a method for manufacturing a double-tongue volute for a centrifugal pump and the double-tongue volute thereof. Background Technology

[0002] During operation, the high-speed rotation of the impeller in a centrifugal pump drives fluid movement. The fluid flow within the pump casing is complex, easily leading to undesirable flow phenomena such as eddies, secondary flows, and boundary separation. These phenomena result in significant fluid energy loss, reducing the efficiency of the centrifugal pump, and also cause pump vibration and noise, affecting its stable operation. Therefore, developing a pump that can effectively suppress undesirable flow phenomena, improve efficiency and stability, optimize the internal flow field, reduce energy consumption, reduce pulsation characteristics, and enhance reliability and comfort has become a current research focus. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method for manufacturing a double-tongue volute for a centrifugal pump, and the double-tongue volute itself, for improving the suppression of undesirable flow phenomena, enhancing efficiency and stability, optimizing the internal flow field, reducing energy consumption, reducing pulsation characteristics, and enhancing reliability and comfort.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing a double-tongue volute for a centrifugal pump, comprising the following steps:

[0005] S1. Preparation of integrated blank: Using investment casting technology, an integrated blank of the volute containing the preliminary structures of the first and second partition tongues is prepared, such that the radial clearance C1 between the first partition tongue and the impeller is less than the radial clearance C2 between the second partition tongue and the impeller.

[0006] S2. Preliminary quality inspection and finishing: The volute blank is scanned using an industrial CT scanner. The porosity in the CT scan image is calculated, and the wall thickness at key locations in the flow channel is measured. The integrated blank that passes the inspection is then finished and polished.

[0007] When the porosity is lower than the first threshold A and the wall thickness is within the design tolerance range, it is judged as a qualified blank and flows into the finishing process;

[0008] When the porosity is between threshold A and a higher threshold B, it is determined to be a repairable product. The defective area is repaired using micro-arc welding technology, and a CT scan is performed again, and the same judgment logic is executed to ensure that the defect has been eliminated to the qualified level.

[0009] If the porosity is higher than the threshold B or the wall thickness is seriously out of tolerance, it is judged as a defective product.

[0010] S3. Tongue Gap Detection: After milling the surface of the integrally formed blank, the coordinates of key points at the heads of the first and second tongues are measured in real time using an in-machine laser probe. Based on the measured coordinates, the actual radial gaps C1 and C2 are calculated according to the three-dimensional digital model, and their ratio C1 / C2 is calculated.

[0011] If C1 < C2, and the value of C1 / C2 is between 2 / 5 and 5 / 6, then it is considered qualified.

[0012] If C1 > C2 or the value of C1 / C2 is not within the range of 2 / 5-5 / 6, it is determined that rework is required. If three consecutive defective products appear within time T, the recorded parameters should be read and the equipment parameters should be readjusted.

[0013] When C1 and C2 increase or decrease simultaneously, check the tool wear and adjust the tool length and radius compensation parameters to a smaller value.

[0014] If the ratio of C1 / C2 continues to deviate in the same direction, check the lead screw backlash and servo motor parameters.

[0015] S4. Surface strengthening treatment of qualified products: The head areas of the first and second tongues and the adjacent flow channel surfaces are shot peened to form a residual compressive stress layer on the surface of the area.

[0016] S5. Performance testing of qualified products: Install the qualified double-tongue volute onto the centrifugal pump and conduct hydraulic performance tests, pressure pulsation tests, and vibration and noise tests. If the product meets the performance indicators in all the above tests, the volute is judged to be a qualified product and is allowed to leave the factory; otherwise, it is judged to be an unqualified product.

[0017] The present invention is further configured such that: in step S3, a cooling device is also provided, the cooling device including an adjustable spray gun and a temperature detector disposed on one side of the spindle. When the temperature of the spindle rises, it will also cause the reference to shift, affecting the deviation of C1 and C2. The specific operation method includes the following steps:

[0018] In S3, C1 and C2 increase or decrease synchronously. First, check if the spindle temperature is too high. Set the real-time temperature to T, the set value temperature to t, and the temperature deviation value ΔT = Tt.

[0019] When |ΔT|≤ΔT1 (small threshold), the controller maintains the current basic flow rate of coolant, the spray gun provides uniform cooling to the spindle, and the tool wear is detected.

[0020] When |ΔT|>ΔT1, it indicates that the spindle is heating up significantly. The controller starts the temperature control compensation program, increases the total flow of coolant according to the preset algorithm, and can instruct the spray gun at a specific angle to enhance the directional spraying of the identified high-temperature points. The controller then adjusts the process to perform three consecutive tests on the processed products. If the products are qualified, the machine continues to run; otherwise, if the products are unqualified, the machine is paused for cooling checks.

[0021] The present invention is further configured such that: in step S4, the shot peening device for shot peening is equipped with a shot breakage rate detection device at the shot loading port. The shot breakage rate detection device includes an automatic sampler disposed on one side of the shot entry channel, a visual inspection unit for observing the outer surface of the shot, and an actuator. The automatic sampler can collect a small number of shot samples currently in use at a set frequency or time interval. The shot peening device is equipped with a shot peening gun for real-time detection of residual stress. The specific operation method includes the following steps:

[0022] Set the residual stress range σ1-σ2, and detect the residual stress as F in real time;

[0023] When σ1 < F < σ2, the equipment operates normally;

[0024] When σ2≤F or F>k*σ2 (where k is a warning coefficient less than 1), a control command is immediately generated to drive the shot peening gun to increase the distance between itself and the workpiece surface and to reduce the shot peening flow rate.

[0025] When F < σ1, the distance between the shot peening gun and the workpiece surface is reduced and the shot peening flow rate is increased. After time interval t, if the value of F does not increase significantly, the shot is collected for breakage rate detection.

[0026] Set the breakage rate value to R, and calculate the particle size distribution of the current projectile;

[0027] When R < preset threshold B1 and the particle size distribution is within the acceptable range, the shot is determined to be in good condition, and the shot peening gun parameters are adjusted further.

[0028] When the preset threshold B1 < R < preset threshold B2, the projectile is determined to be in a state of degradation, and the system issues a warning to the operator that the projectile performance has deteriorated and suggests preparing for replacement.

[0029] When R > preset threshold B2, the projectile is determined to be in an unqualified state, the equipment is immediately stopped, and the projectile is replaced.

[0030] A double-tongue volute for a centrifugal pump, manufactured by the method according to claims 1-3, comprises a volute body having a spiral flow channel inside. Two radially extending first and second tongues are provided near the outlet diffuser section of the volute body. The first and second tongues are arranged back and forth along the spiral direction of the flow channel and divide the inlet of the outlet diffuser section into at least two flow channel regions. The double-tongue structure formed by the first and second tongues is configured to suppress the wake and jet effects at the impeller outlet, reduce the generation of vortices and secondary flows inside the volute, thereby optimizing the internal flow field state.

[0031] The present invention is further configured such that: the first tongue is located near the impeller side, and the radial clearance between it and the outer edge of the impeller is C1; the second tongue is located downstream of the first tongue, and the radial clearance between it and the outer edge of the impeller is C2; wherein, C1 < C2.

[0032] The present invention is further configured such that the ratio of the radial clearance C1 to C2 is in the range of 2 / 5 to 5 / 6.

[0033] The present invention is further configured such that the tongue angles of the first and second tongues are different, wherein the tongue angle is the angle between the working surface of the tongue and the direction of the absolute velocity of the fluid at the impeller outlet.

[0034] The present invention is further configured such that the heads of the first and second tongues are rounded or elliptical structures.

[0035] The present invention is further configured such that the outlet diffusion section is a tapered or rectangular tube with a cross-sectional area that gradually increases along the fluid direction.

[0036] The beneficial effects of this invention are:

[0037] 1. Through the coordinated efforts of multiple stages, including integrated billet preparation, precision quality inspection and finishing, real-time monitoring and adjustment of the tongue gap, surface strengthening treatment, and comprehensive performance testing, the product's quality consistency and reliability are significantly improved. Integrated molding using investment casting, combined with industrial CT scanning and micro-arc welding repair, effectively controls porosity and wall thickness, reduces internal defects, and ensures the integrity and dimensional stability of the volute structure. Real-time monitoring of the tongue gap using an in-machine laser probe, along with automatic adjustment of equipment parameters based on data feedback, avoids batch deviations and improves production efficiency and product qualification rate. Shot peening of key areas of the tongue forms a residual compressive stress layer, significantly improving fatigue resistance and cavitation resistance, and extending the volute's service life. Finally, hydraulic performance, pressure pulsation, and vibration noise tests ensure the product meets stringent operating conditions, reducing energy consumption and noise during pump operation and improving overall system efficiency.

[0038] 2. In step S3, the spindle temperature is monitored and compensated in real time as a key variable affecting the tongue clearance. An intelligent cooling device actively suppresses reference deviations caused by spindle thermal expansion, intervening at the source of error. This makes the control of the C1 and C2 clearances more stable and precise, significantly reducing the risk of batch quality fluctuations caused by ambient temperature rise. In step S4, the real-time detection results of residual stress are dynamically linked with shot peening process parameters (distance, flow rate), achieving quantitative spraying of the strengthening effect. Simultaneously, an innovative shot breakage rate detection mechanism accurately diagnoses shot performance degradation, providing timely warnings or requiring shot replacement. This fundamentally avoids the problem of uneven or insufficient strengthening layer quality caused by medium failure, ensuring the uniformity and consistency of the residual compressive stress layer on the surface of each product.

[0039] 3. The double-tongue structure, arranged front and rear with a specific clearance ratio (C1 / C2), can guide the fluid discharged from the impeller smoothly and in stages. It effectively suppresses the strong wake-jet interference effect of a single-tongue structure, significantly reducing flow and impact losses within the volute, thereby widening the pump's high-efficiency range and improving overall operating efficiency. The double-tongue structure decomposes the dynamic and static interference between the impeller and the tongues into two locations, disrupting a single, intense pressure pulsation source and making the pressure field inside the volute more uniform and stable. This characteristic can significantly reduce the pressure pulsation amplitude during centrifugal pump operation, thereby reducing vibration and fluid noise, and improving the pump unit's operational smoothness and quietness.

[0040] 4. By setting two baffles with C1 < C2 and a C1 / C2 ratio between 2 / 5 and 5 / 6, a clear primary and secondary flow guiding structure is formed, working in synergy. The first baffle (main baffle) is responsible for initially integrating and guiding the high-speed fluid discharged from the impeller, while the second baffle (secondary baffle) performs secondary rectification, smoothly guiding it into the outlet diffuser section. This staged flow guiding mode can more effectively suppress the wake-jet effect at the impeller outlet, significantly weaken the vortices and secondary flows within the volute, thereby reducing hydraulic losses and improving the operating efficiency of the centrifugal pump. By setting different tongue angles for the first and second baffles, the working surface of each baffle can more accurately match the absolute velocity direction of the fluid at its location. The head shape of the first and second baffles is designed with rounded corners or an elliptical structure, which can effectively avoid stress concentration caused by sharp corners, greatly improving the fatigue resistance and cavitation resistance of the baffle tongue. The outlet diffuser section uses a tapered or rectangular tube with a gradually increasing cross-sectional area, which can efficiently convert the kinetic energy of the fluid into pressure energy, increasing the pump head. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating an embodiment of a manufacturing method for a double-tongue volute for a centrifugal pump according to the present invention.

[0042] Figure 2 This is a flowchart of the cooling device of the present invention;

[0043] Figure 3 Flowcharts for residual stress detection and projectile fragmentation rate detection;

[0044] Figure 4 This is a schematic diagram of the three-dimensional structure of a double-septate volute.

[0045] Figure 5 This is a magnified view of a portion of the double-septate sulcus.

[0046] Figure 1-5 Reference numerals: 1. Volute body; 2. First diaphragm; 3. Second diaphragm; 4. Outlet diffuser section. Detailed Implementation

[0047] Reference Figure 1-5 The embodiments of the present invention will be further described below.

[0048] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0049] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0050] Figures 1 to 5 The method for manufacturing a double-tongue volute for a centrifugal pump, as shown, includes the following steps:

[0051] S1. Preparation of integrated blank: Using investment casting technology, an integrated blank of the volute containing the preliminary structure of the first tongue 2 and the second tongue 3 is prepared, such that the radial clearance C1 between the first tongue 2 and the impeller is less than the radial clearance C2 between the second tongue 3 and the impeller.

[0052] S2. Preliminary quality inspection and finishing: The volute blank is scanned using an industrial CT scanner. The porosity in the CT scan image is calculated, and the wall thickness at key locations in the flow channel is measured. The integrated blank that passes the inspection is then finished and polished.

[0053] When the porosity is lower than the first threshold A and the wall thickness is within the design tolerance range, it is judged as a qualified blank and flows into the finishing process;

[0054] When the porosity is between threshold A and a higher threshold B, it is determined to be a repairable product. The defective area is repaired using micro-arc welding technology, and a CT scan is performed again, and the same judgment logic is executed to ensure that the defect has been eliminated to the qualified level.

[0055] If the porosity is higher than the threshold B or the wall thickness is seriously out of tolerance, it is judged as a defective product.

[0056] S3. Tongue Gap Detection: After milling the surface of the integrally formed blank, the coordinates of key points at the head of the first tongue 2 and the second tongue 3 are measured in real time using an in-machine laser probe. Based on the coordinates of the measured points, the actual radial gaps C1 and C2 are calculated according to the three-dimensional digital model, and their ratio C1 / C2 is calculated:

[0057] If C1 < C2, and the value of C1 / C2 is between 2 / 5 and 5 / 6, then it is considered qualified.

[0058] If C1 > C2 or the value of C1 / C2 is not within the range of 2 / 5-5 / 6, it is determined that rework is required. If three consecutive defective products appear within time T, the recorded parameters should be read and the equipment parameters should be readjusted.

[0059] When C1 and C2 increase or decrease simultaneously, check the tool wear and adjust the tool length and radius compensation parameters to a smaller value.

[0060] If the ratio of C1 / C2 continues to deviate in the same direction, check the lead screw backlash and servo motor parameters.

[0061] S4. Surface strengthening treatment of qualified products: The head area of ​​the first tongue 2 and the second tongue 3 and the adjacent flow channel surface are subjected to shot peening treatment to form a residual compressive stress layer on the surface of the area.

[0062] S5. Performance testing of qualified products: Install the qualified double-tongue volute onto the centrifugal pump and conduct hydraulic performance tests, pressure pulsation tests, and vibration and noise tests. If the product meets the performance indicators in all the above tests, the volute is judged to be a qualified product and is allowed to leave the factory; otherwise, it is judged to be an unqualified product.

[0063] Through a multi-stage collaborative process involving integrated billet preparation, precision quality inspection and finishing, real-time monitoring and adjustment of the tongue gap, surface strengthening treatment, and comprehensive performance testing, the product's quality consistency and reliability are significantly improved. Integrated investment casting, combined with industrial CT scanning and micro-arc welding repair, effectively controls porosity and wall thickness, reduces internal defects, and ensures the integrity and dimensional stability of the volute structure. Real-time monitoring of the tongue gap using an in-machine laser probe, along with automatic adjustment of equipment parameters based on data feedback, avoids batch deviations and improves production efficiency and product qualification rate. Shot peening of key areas of the tongue creates a residual compressive stress layer, significantly improving fatigue and cavitation resistance and extending the volute's service life. Finally, hydraulic performance, pressure pulsation, and vibration noise tests ensure the product meets stringent operating conditions, reducing energy consumption and noise during pump operation and improving overall system efficiency.

[0064] The S3 step also includes a cooling device, which comprises an adjustable spray gun and a temperature detector located on one side of the spindle. When the spindle temperature rises, it will also cause a reference offset, affecting the deviation of C1 and C2. The specific operation method includes the following steps:

[0065] In S3, C1 and C2 increase or decrease synchronously. First, check if the spindle temperature is too high. Set the real-time temperature to T, the set value temperature to t, and the temperature deviation value ΔT = Tt.

[0066] When |ΔT|≤ΔT1 (small threshold), the controller maintains the current basic flow rate of coolant, the spray gun provides uniform cooling to the spindle, and the tool wear is detected.

[0067] When |ΔT|>ΔT1, it indicates that the spindle is heating up significantly. The controller starts the temperature control compensation program, increases the total flow of coolant according to the preset algorithm, and can instruct the spray gun at a specific angle to enhance the directional spraying of the identified high-temperature points. The controller then adjusts the process to perform three consecutive tests on the processed products. If the products are qualified, the machine continues to run; otherwise, if the products are unqualified, the machine is paused for cooling checks.

[0068] In step S3, spindle temperature is monitored and compensated in real time as a key variable affecting the tongue clearance. An intelligent cooling system actively suppresses reference deviations caused by spindle thermal expansion, intervening at the source of error. This results in more stable and precise control of the C1 and C2 clearances, significantly reducing the risk of batch quality fluctuations caused by ambient temperature rise.

[0069] In step S4, the shot peening device is equipped with a shot breakage rate detection device at its loading port. This device includes an automatic sampler located on one side of the shot entry channel, a visual inspection unit for observing the outer surface of the shot, and an actuator. The automatic sampler can collect a small number of currently used shot samples at a set frequency or time interval. The shot peening device is equipped with a shot peening gun for real-time residual stress detection. The specific operation method includes the following steps:

[0070] Set the residual stress range σ1-σ2, and detect the residual stress as F in real time;

[0071] When σ1 < F < σ2, the equipment operates normally;

[0072] When σ2≤F or F>k*σ2 (where k is a warning coefficient less than 1), a control command is immediately generated to drive the shot peening gun to increase the distance between itself and the workpiece surface and to reduce the shot peening flow rate.

[0073] When F < σ1, the distance between the shot peening gun and the workpiece surface is reduced and the shot peening flow rate is increased. After time interval t, if the value of F does not increase significantly, the shot is collected for breakage rate detection.

[0074] Set the breakage rate value to R, and calculate the particle size distribution of the current projectile;

[0075] When R < preset threshold B1 and the particle size distribution is within the acceptable range, the shot is determined to be in good condition, and the shot peening gun parameters are adjusted further.

[0076] When the preset threshold B1 < R < preset threshold B2, the projectile is determined to be in a state of degradation, and the system issues a warning to the operator that the projectile performance has deteriorated and suggests preparing for replacement.

[0077] When R > preset threshold B2, the projectile is determined to be in an unqualified state, the equipment is immediately stopped, and the projectile is replaced.

[0078] In step S4, the real-time detection results of residual stress are dynamically linked with the shot peening process parameters (distance, flow rate), enabling quantitative spraying of the strengthening effect. Simultaneously, the innovative shot breakage rate detection mechanism accurately diagnoses the shot performance degradation, providing timely warnings or requiring shutdown and shot replacement. This fundamentally avoids the problem of uneven or insufficient strengthening layer quality caused by medium failure, ensuring the uniformity and consistency of the residual compressive stress layer on the surface of each product.

[0079] A double-tongue volute manufactured according to the aforementioned method for manufacturing a double-tongue volute for a centrifugal pump includes a volute body 1 with an internal helical flow channel. Two radially extending first and second tongues 3 are provided near the outlet diffuser section 4 of the volute body 1. The first and second tongues 2 and 3 are arranged front-to-back along the helical direction of the flow channel, dividing the inlet of the outlet diffuser section 4 into at least two flow channel regions. The double-tongue structure formed by the first and second tongues 3 is configured to suppress the wake and jet effects at the impeller outlet, reduce the generation of vortices and secondary flows within the volute, thereby optimizing the internal flow field. The double-tongue structure, arranged front-to-back with a specific clearance ratio (C1 / C2), can guide the fluid discharged from the impeller smoothly and in stages. It effectively suppresses the strong wake-jet interference effect of a single-tongue structure, significantly reduces flow losses and impact losses within the volute, thereby widening the pump's high-efficiency zone and improving overall operating efficiency. The double-tongue structure decomposes the dynamic and static interference between the impeller and the tongue into two locations, disrupting a single, intense pressure pulsation source and making the pressure field inside the volute more uniform and stable. This characteristic can significantly reduce the pressure pulsation amplitude during centrifugal pump operation, thereby reducing vibration and fluid noise, and improving the smoothness and quietness of pump unit operation.

[0080] The first tongue 2 is located near the impeller, and its radial clearance with the outer edge of the impeller is C1. The second tongue 3 is located downstream of the first tongue 2, and its radial clearance with the outer edge of the impeller is C2. C1 < C2. The smaller C1 allows the first tongue 2 to more effectively block and regulate the high-speed fluid at the impeller outlet, suppressing the initial formation of wake and jet. The larger C2 downstream allows the second tongue 3 to further buffer and redistribute the fluid based on the initial regulation of the first tongue 2, allowing the fluid to enter the outlet diffuser section 4 more smoothly, optimizing the flow field inside the volute, improving the efficiency and operational stability of the centrifugal pump, expanding its operating range, and reducing maintenance costs.

[0081] When the ratio of the radial clearance C1 to C2 is less than 2 / 5, the fluid at the impeller outlet is excessively blocked when it encounters the first baffle 2, resulting in significant local resistance. Strong turbulence and vortices form near the first baffle 2, increasing energy loss. When the ratio of the radial clearance C1 to C2 is greater than 5 / 6, wake and jet phenomena cannot be effectively controlled, leading to turbulent flow within the volute. High-speed jets directly impact the second baffle 3, forming strong vortices and secondary flows near it, disrupting the orderly control of the fluid by the double baffle structure and preventing the internal flow field from reaching an optimized state. Therefore, the optimal range for the ratio of the radial clearance C1 to C2 is 2 / 5 to 5 / 6, which more effectively suppresses the wake-jet effect at the impeller outlet, significantly weakens vortices and secondary flows within the volute, thereby reducing hydraulic losses and improving the operating efficiency of the centrifugal pump.

[0082] The tongue angles of the first tongue 2 and the second tongue 3 are different. The tongue angle is the angle between the working surface of the tongue and the absolute velocity direction of the fluid at the impeller outlet. This allows the working surface of each tongue to more accurately match the absolute velocity direction of the fluid at its location, minimizing the impact of the fluid on the tongue. This not only further reduces impact loss and noise, but also alleviates the load on the tongue, helping to improve its long-term reliability.

[0083] The first tongue 2 and the second tongue 3 have rounded or elliptical head shapes, which can effectively avoid stress concentration caused by sharp corners, greatly improve the fatigue resistance and cavitation resistance of the tongue, and thus extend the service life of the volute under harsh working conditions.

[0084] The outlet diffuser section 4 is a tapered or rectangular tube with a gradually increasing cross-sectional area along the fluid direction, which can efficiently convert the kinetic energy of the fluid into pressure energy, increase the pump head, and optimize the flow field with double tongues, so that the volute can maintain good performance stability under various flow conditions, thus broadening the high-efficiency operating range of the centrifugal pump.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a double-tongue volute for a centrifugal pump, characterized in that, Includes the following steps: S1. Preparation of integrated blank: Using investment casting technology, an integrated blank of the volute containing the preliminary structure of the first tongue (2) and the second tongue (3) is prepared, so that the radial clearance C1 between the first tongue (2) and the impeller is less than the radial clearance C2 between the second tongue (3) and the impeller. S2. Preliminary quality inspection and finishing: The volute blank is scanned using an industrial CT scanner. The porosity in the CT scan image is calculated, and the wall thickness at key locations in the flow channel is measured. The integrated blank that passes the inspection is then finished and polished. When the porosity is lower than the first threshold A and the wall thickness is within the design tolerance range, it is judged as a qualified blank and flows into the finishing process; When the porosity is between threshold A and a higher threshold B, it is determined to be a repairable product. The defective area is repaired using micro-arc welding technology, and a CT scan is performed again, and the same judgment logic is executed to ensure that the defect has been eliminated to the qualified level. If the porosity is higher than the threshold B or the wall thickness is seriously out of tolerance, it is judged as a defective product. S3. Tongue Gap Detection: After milling the surface of the integrally formed blank, the coordinates of the key points of the head of the first tongue (2) and the second tongue (3) are measured in real time using an in-machine laser probe. Based on the coordinates of the measuring points, the actual radial gaps C1 and C2 are calculated according to the three-dimensional digital model, and their ratio C1 / C2 is calculated: If C1 < C2, and the value of C1 / C2 is between 2 / 5 and 5 / 6, then it is considered qualified. If C1 > C2 or the value of C1 / C2 is not within the range of 2 / 5-5 / 6, it is determined that rework is required. If three consecutive defective products appear within time T, the recorded parameters should be read and the equipment parameters should be readjusted. When C1 and C2 increase or decrease simultaneously, check the tool wear and adjust the tool length and radius compensation parameters to a smaller value. If the ratio of C1 / C2 continues to deviate but in the same direction, check the lead screw backlash and servo motor parameters. S4. Surface strengthening treatment of qualified products: The head area of ​​the first tongue (2) and the second tongue (3) and the adjacent flow channel surface are subjected to surface shot peening treatment to form a residual compressive stress layer on the surface of the area. S5. Performance testing of qualified products: Install the qualified double-tongue volute onto the centrifugal pump and conduct hydraulic performance tests, pressure pulsation tests, and vibration and noise tests. If the product meets the performance indicators in all the above tests, the volute is judged to be a qualified product and is allowed to leave the factory; otherwise, it is judged to be an unqualified product.

2. The method for manufacturing a double-tongue volute for a centrifugal pump according to claim 1, characterized in that, The S3 step also includes a cooling device, which comprises an adjustable spray gun and a temperature detector located on one side of the spindle. When the spindle temperature rises, it will also cause a reference offset, affecting the deviation of C1 and C2. The specific operation method includes the following steps: In step S3, C1 and C2 increase or decrease synchronously. First, check if the spindle temperature is too high. Set the real-time temperature to T, the set value temperature to t, and the temperature deviation value ΔT=Tt. When |ΔT|≤ΔT1, the controller maintains the current basic flow rate of coolant, the spray gun provides uniform cooling to the spindle, and the tool wear is detected. When |ΔT|>ΔT1, it indicates that the spindle is heating up significantly. The controller starts the temperature control compensation program, increases the total flow of coolant according to the preset algorithm, and can instruct the spray gun at a specific angle to enhance the directional spraying of the identified high-temperature points. The controller then adjusts the process to perform three consecutive tests on the processed products. If the products are qualified, the machine continues to run; otherwise, if the products are unqualified, the machine is paused for cooling checks.

3. A method for manufacturing a double-tongue volute for a centrifugal pump according to claim 1, characterized in that, In step S4, the shot peening device is equipped with a shot breakage rate detection device at its loading port. This device includes an automatic sampler located on one side of the shot entry channel, a visual inspection unit for observing the outer surface of the shot, and an actuator. The automatic sampler can collect a small number of currently used shot samples at a set frequency or time interval. The shot peening device is equipped with a shot peening gun for real-time residual stress detection. The specific operation method includes the following steps: Set the residual stress range σ1-σ2, and detect the residual stress as F in real time; When σ1 < F < σ2, the equipment operates normally; When σ2≤F or F>k*σ2, where k is a warning coefficient less than 1, a control command is immediately generated to drive the shot peening gun to increase the distance between itself and the workpiece surface and to reduce the shot peening flow rate. When F < σ1, the distance between the shot peening gun and the workpiece surface is reduced and the shot peening flow rate is increased. After time interval t, if the value of F does not increase significantly, the shot is collected for breakage rate detection. Set the breakage rate value to R, and calculate the particle size distribution of the current projectile; When R < preset threshold B1 and the particle size distribution is within the acceptable range, the shot is determined to be in good condition, and the shot peening gun parameters are adjusted further. When the preset threshold B1 < R < preset threshold B2, the projectile is determined to be in a state of degradation, and the system issues a warning to the operator that the projectile performance has deteriorated and suggests preparing for replacement. When R > preset threshold B2, the projectile is determined to be in an unqualified state, the equipment is immediately stopped, and the projectile is replaced.

4. A double-tongue volute for a centrifugal pump manufactured according to any one of claims 1-3, comprising a volute body (1) having an internal helical flow channel, characterized in that, Near the outlet diffuser section (4) of the volute body (1), there are two radially extending first and second baffles (3). The first baffle (2) and the second baffle (3) are arranged back and forth along the spiral direction of the flow channel and divide the inlet of the outlet diffuser section (4) into at least two flow channel regions. The double baffle structure formed by the first baffle and the second baffle (3) is configured to suppress the wake and jet effect of the impeller outlet, reduce the generation of vortices and secondary flows in the volute, and thus optimize the internal flow field state.

5. A double-tongue volute for a centrifugal pump according to claim 4, characterized in that, The first tongue (2) is located near the impeller, and the radial gap between it and the outer edge of the impeller is C1. The second tongue (3) is located downstream of the first tongue (2), and the radial gap between it and the outer edge of the impeller is C2, wherein C1 < C2.

6. A double-tongue volute for a centrifugal pump according to claim 4, characterized in that, The ratio of the radial clearance C1 to C2 ranges from 2 / 5 to 5 / 6.

7. A double-tongue volute for a centrifugal pump according to claim 4, characterized in that, The tongue angles of the first tongue (2) and the second tongue (3) are different. The tongue angle is the angle between the working surface of the tongue and the direction of the absolute velocity of the fluid at the impeller outlet.

8. A double-tongue volute for a centrifugal pump according to claim 4, characterized in that, The head shape of the first tongue (2) and the second tongue (3) is rounded or elliptical.

9. A double-tongue volute for a centrifugal pump according to claim 4, characterized in that, The outlet diffusion section (4) is a tapered or rectangular tube with a cross-sectional area that gradually increases along the fluid direction.

Images