Precision casting process of stainless steel impeller for nuclear power

Abstract

The invention relates to the field of precision casting, and discloses a precision casting process for a stainless steel impeller for nuclear power, which comprises the following steps of: S1, pressing a wax mold by using an investment casting process, and connecting the wax mold into a tree shape by using a wax rod; s2, the surface of the wax mold is coated with a refractory material, dewaxing is conducted through dewaxing equipment after drying, a hollow shell is obtained, and then high-temperature roasting is conducted; s3, selecting duplex stainless steel to be smelted in an electric furnace, heating molten steel to a preset pouring temperature, and pouring the molten steel into the shell from the bottom or the side; s4, the shell is removed after being naturally cooled, and solution treatment is conducted on the impeller; s5, carrying out sand blasting, shot blasting and sand cleaning, and carrying out nondestructive inspection; wherein dewaxing equipment used in the step S2 comprises a tank body, a rotatable tray is arranged in the tank body, and a plurality of adjustable fixing clamps are arranged on the tray to meet the fixing requirements of different shells; the top of the tank body is provided with a feed port, a discharge port and an automatic sealing door, and the bottom is connected with a wax liquid collecting tank and is internally provided with a liquid level sensor; the inner wall of the tank body is provided with a heating cavity for containing heating elements, and the outer wall is wrapped with heat insulation materials.

Description

Technical Field

[0001] The present invention relates to the field of precision casting, and particularly to a precision casting process for stainless steel impellers used in nuclear power plants. Background Art

[0002] As an efficient and low-carbon energy form, nuclear power is playing an increasingly important role in the energy structure. The safe and stable operation of nuclear power equipment is of crucial importance. Among them, stainless steel impellers, as key components, are widely used in equipment such as pumps and compressors in nuclear power systems, and their performance directly affects the efficiency and reliability of the entire nuclear power system.

[0003] Traditional stainless steel impeller casting processes have certain limitations when facing the strict requirements of the nuclear power field for high precision, high reliability, and corrosion resistance of impellers. For example, in the dewaxing step of the precision casting process for stainless steel impellers used in nuclear power, traditional dewaxing equipment often has problems such as long dewaxing time, a large amount of wax residue, and high energy consumption, which affect the overall production efficiency and product quality. Therefore, it is of great practical significance to develop an advanced precision casting process for stainless steel impellers used in nuclear power. Summary of the Invention

[0004] The purpose of the present invention is to provide a precision casting process for stainless steel impellers used in nuclear power, and solve at least one of the technical problems such as long dewaxing time, a large amount of wax residue, and high energy consumption existing in traditional dewaxing equipment.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A precision casting process for stainless steel impellers used in nuclear power, including the following steps:

[0007] S1. Use the investment casting process to press wax patterns, and connect individual wax patterns into a tree-like structure through wax rods;

[0008] S2. Coat the surface of the wax pattern with refractory materials. After the coating is dried, dewax the shell using dewaxing equipment to obtain a hollow shell, and then put the shell into a high-temperature furnace for roasting;

[0009] S3. Select duplex stainless steel materials for melting in an electric furnace, heat the melted steel to a predetermined pouring temperature, and pour it into the shell using bottom pouring or side pouring;

[0010] S4: After the shell is naturally cooled, remove the shell to obtain the impeller and perform solution treatment;

[0011] S5. Remove the residues on the surface and inside of the impeller by sandblasting and shot peening, and perform flaw detection using non-destructive testing techniques;

[0012] The dewaxing equipment used in S2 includes: a controller and a tank body, a rotating motor is arranged in the tank body, a tray is arranged at the output end of the rotating motor, a plurality of electric slide rails are arranged on the tray, and a fixing clamp is installed on the electric slide rail; a feed port and a discharge port are opened on the top of the tank body, and both the feed port and the discharge port are equipped with automatic sealing doors; a wax liquid collecting tank is connected to the bottom of the tank body, and a liquid level sensor is arranged in the wax liquid collecting tank; a heating chamber is arranged on the inner wall of the tank body, a heating element is arranged in the heating chamber, and the outer wall of the tank body is wrapped with heat insulation material.

[0013] Furthermore, the dewaxing equipment also includes: an auxiliary dewaxing mechanism;

[0014] The auxiliary dewaxing mechanism includes: an ultrasonic dewaxing tank and an air compressor. The ultrasonic dewaxing tank is arranged on a tray, and a plurality of ultrasonic transducers are evenly distributed inside the ultrasonic dewaxing tank; the air compressor is installed on the outside of the tank body, and the air compressor is connected to the inside of the shell through a pipeline, and an air nozzle with an adjustable angle is installed at the end of the pipeline.

[0015] Furthermore, an angle adjustment component is provided at the end of the pipe, and the angle adjustment component is used to adjust the angle of the air nozzle;

[0016] The angle adjustment assembly includes a screw rod, which is rotatably installed on the end of the pipeline. A ring capable of spiral motion is sleeved on the screw rod, and a nozzle is fixed on the ring. The nozzle and the pipeline are softly connected by a hose. The end of the screw rod is connected to a drive motor, and the drive motor is installed on the end of the pipeline.

[0017] Furthermore, the auxiliary dewaxing mechanism also includes: a lifting component, which is used to enable the pipeline to enter and exit the mold shell; the lifting component includes:

[0018] A lifting bracket installed on the top of the tank body, the lifting bracket includes a vertically arranged guide rail and a slider that can slide up and down along the guide rail, a horizontal mounting plate is fixedly connected to the slider, and the pipeline is fixedly mounted on the mounting plate;

[0019] The lifting drive module is connected to the slider in a transmission manner and is used to drive the slider to move up and down along the guide rail, thereby driving the pipeline to move up and down so that the pipeline can enter and exit the mold shell.

[0020] Furthermore, the lifting drive module includes: a float arranged in the wax liquid collecting tank, a connecting rod fixed on the top of the float, an inclined block fixed on the other end of the connecting rod, the inclined block limited sliding installation on the tank wall of the wax liquid collecting tank, the inclined block contacts with a rack on one side, the rack limited sliding installation on the tank wall of the wax liquid collecting tank, and a return spring is arranged on the side of the rack away from the inclined block, and the rack is meshed with the gear, the gear is coaxially fixed to the bottom end of the screw, the screw is spirally connected to the slider, and the screw is rotatably installed on the lifting bracket.

[0021] Further, the lifting drive module includes: an electric push rod or a hydraulic cylinder. The air compressor is electrically connected to the liquid level switch, and the liquid level switch is electrically connected to the liquid level sensor;

[0022] The controller is electrically connected to the liquid level sensor and the lifting drive module; when the liquid level sensor detects that the height of the wax liquid in the wax liquid collection tank reaches the first set value, and the second set value is greater than the first set value, the controller controls the lifting drive module to act, so that the pipeline descends into the inside of the mold shell; when the liquid level sensor detects that the height of the wax liquid in the wax liquid collection tank reaches the first set value, while the air compressor starts to work, the controller controls the lifting drive module to lower the pipeline.

[0023] Further, a limiting block is arranged on the tank wall of the wax liquid collection tank, and the distance between the limiting block and the bottom wall of the lower wax liquid collection tank serves as the moving space for the floating ball.

[0024] Further, two jet nozzles are installed at the end of the pipeline and are symmetrically distributed in a Y shape.

[0025] Advantages of the present invention:

[0026] (1) In the present invention, the rotational design of the tray makes the mold shell heat more evenly during the heating process, avoiding the problem of uneven melting of the wax mold caused by local temperature differences, and accelerating the overall dewaxing speed; at the same time, the ultrasonic waves generated by the ultrasonic dewaxing tank can destroy the adhesion between the wax liquid and the mold shell, making the wax liquid easier to flow out of the mold shell; the air compressor cooperates with the adjustable-angle jet nozzle to blow air at the complex parts inside the mold shell, effectively removing the residual wax liquid and further improving the dewaxing efficiency.

[0027] (2) In the present invention, the liquid level sensor monitors the height of the wax liquid in real time, and the controller precisely controls the operation of the lifting drive module and the air compressor according to the liquid level situation, ensuring that the pipeline enters and exits the mold shell at the appropriate time, and the air is blown into the mold shell at the appropriate time, guaranteeing the accuracy and stability of the dewaxing process; moreover, the jet nozzles symmetrically distributed in a Y shape at the end of the pipeline can cover a wider area inside the mold shell, enabling the compressed air to act evenly on the inside of the mold shell, reducing the wax liquid residue and improving the dewaxing quality. Brief Description of the Drawings

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 is the process step diagram of the present invention;

[0030] Figure 2 is the partial three-dimensional schematic diagram of the dewaxing equipment in the present invention;

[0031] Figure 3 is Figure 2 the bottom schematic diagram of

[0032] Figure 4 This is a schematic structural diagram of the lifting component in the present invention;

[0033] Figure 5 This is a schematic structural diagram of the angle adjustment component in the present invention.

[0034] Description of the drawings: 1. Tank body; 2. Rotating motor; 3. Tray; 4. Electric sliding rail; 5. Fixed fixture; 6. Wax liquid collection tank; 7. Heating chamber; 8. Heating element; 9. Auxiliary dewaxing mechanism; 91. Ultrasonic dewaxing tank; 92. Ultrasonic transducer; 93. Pipeline; 94. Jet nozzle; 95. Angle adjustment component; 951. Lead screw; 952. Collar; 953. Hose; 954. Driving motor; 96. Lifting component; 961. Lifting bracket; 962. Guide rail; 963. Slide block; 964. Mounting plate; 965. Lifting drive module; 9651. Floating ball; 9652. Connecting rod; 9653. Rack; 9654. Gear; 9655. Lead screw; 967. Limit block. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] Please refer to Figures 1-5 as shown, the present invention is a precision casting process for stainless steel impellers used in nuclear power plants, including the following steps:

[0037] S1. Use the investment casting process to press wax molds, and connect individual wax molds into a tree-like structure through wax rods;

[0038] S2. Coat the surface of the wax mold with refractory materials. After the coating is dried, dewax the shell mold using dewaxing equipment to obtain a hollow shell mold, and then put the shell mold into a high-temperature furnace for roasting;

[0039] S3. Select duplex stainless steel materials for melting in an electric furnace, heat the melted steel water to a predetermined pouring temperature, and pour it into the shell mold using bottom pouring or side pouring;

[0040] S4: After the shell mold is naturally cooled, remove the shell mold to obtain the impeller and perform solution treatment;

[0041] S5. Remove the residues on the surface and inside of the impeller by sandblasting and shot peening, and perform flaw detection using non-destructive testing techniques;

[0042] The dewaxing equipment used in S2 includes: a controller and a tank body 1. A rotating motor 2 is arranged inside the tank body 1. The output end of the rotating motor 2 is provided with a tray 3. A plurality of electric slide rails 4 are arranged on the tray 3, and a fixed fixture 5 is installed on the electric slide rails 4. The top of the tank body 1 is provided with a feed inlet and a discharge outlet, and both the feed inlet and the discharge outlet are equipped with automatic sealing doors. The bottom of the tank body 1 is connected with a wax liquid collection tank 6, and a liquid level sensor is arranged inside the wax liquid collection tank 6. The inner wall of the tank body 1 is provided with a heating cavity 7, a heating element 8 is arranged inside the heating cavity 7, and the outer wall of the tank body 1 is wrapped with heat insulation materials. The controller is electrically connected with the electrical components;

[0043] The dewaxing equipment further includes: an auxiliary dewaxing mechanism 9;

[0044] The auxiliary dewaxing mechanism 9 includes: an ultrasonic dewaxing tank 91 and an air compressor. The ultrasonic dewaxing tank 91 is arranged on the tray 3, and a plurality of ultrasonic transducers 92 are evenly distributed inside the ultrasonic dewaxing tank 91. The air compressor is installed outside the tank body 1, and the air compressor is connected to the inside of the shell through a pipeline 93. A jet nozzle 94 with an adjustable angle is installed at the end of the pipeline 93. There are two jet nozzles 94 installed at the end of the pipeline 93, and they are symmetrically distributed in a Y shape.

[0045] An angle adjustment component 95 is arranged at the end of the pipeline 93, and the angle adjustment component 95 is used to adjust the angle of the jet nozzle 94;

[0046] The angle adjustment component 95 includes a lead screw 951. The lead screw 951 is rotatably installed at the end of the pipeline 93. A collar 952 capable of spiral movement is sleeved on the lead screw 951. A nozzle is fixedly arranged on the collar 952, and the nozzle is flexibly connected to the pipeline 93 through a flexible hose 953. The end of the lead screw 951 is connected to a driving motor 954, and the driving motor 954 is installed at the end of the pipeline 93.

[0047] The auxiliary dewaxing mechanism 9 further includes: a lifting component 96. The lifting component 96 is used to realize the movement of the pipeline 93 in and out of the shell. The lifting component 96 includes:

[0048] A lifting bracket 961 installed at the inner top of the tank body 1. The lifting bracket 961 includes a vertically arranged guide rail 962 and a slider 963 that can slide up and down along the guide rail 962. A horizontal mounting plate 964 is fixedly connected to the slider 963, and the pipeline 93 is fixedly installed on the mounting plate 964;

[0049] A lifting drive module 965. The lifting drive module 965 is in transmission connection with the slider 963 and is used to drive the slider 963 to move up and down along the guide rail 962, thereby driving the pipeline 93 to move up and down, so that the pipeline 93 can enter and exit the shell.

[0050] The controller is electrically connected to the liquid level sensor and the lifting drive module 965; when the liquid level sensor detects that the height of the wax liquid in the wax liquid collection tank 6 reaches the first set value, and the second set value is greater than the first set value, the controller controls the lifting drive module 965 to act, so that the pipeline 93 descends into the inside of the mold shell; when the liquid level sensor detects that the height of the wax liquid in the wax liquid collection tank 6 reaches the first set value, while the air compressor starts to work, the controller controls the lifting drive module 965 to lower the pipeline 93.

[0051] In the present invention, through the feeding port at the top of the tank body 1, taking advantage of the opportunity when the automatic sealing door is opened, the mold shell coated with refractory material and dried is placed on the tray 3; at this time, the operator can control the electric slide rail 4 through the controller to adjust the position of the fixing fixture 5 to adapt to mold shells of different sizes and shapes, and firmly fix the mold shell on the tray 3; the controller controls the heating element 8 in the heating chamber 7 to start working, heating the inside of the tank body 1, so that the wax mold in the mold shell gradually melts; at the same time, the controller controls the rotation motor 2 to start, driving the tray 3 to rotate, making the mold shell receive heat more evenly, accelerating the melting speed of the wax mold, and the melted wax liquid flows along the mold shell into the wax liquid collection tank 6 at the bottom of the tank body 1;

[0052] The liquid level sensor in the wax liquid collection tank 6 monitors the height of the wax liquid in real time; when the liquid level sensor detects that the height of the wax liquid reaches the second set value, and the second set value is greater than the first set value, the controller controls the lifting drive module 965 to act;

[0053] When the liquid level sensor detects that the height of the wax liquid in the wax liquid collection tank 6 reaches the first set value, the liquid level switch controls the air compressor to start working, and compressed air is delivered to the inside of the mold shell through the pipeline 93; at the same time, the controller can control the drive motor 954 to drive the lead screw 951 to rotate, so that the collar 952 moves spirally on the lead screw 951, thereby adjusting the angle of the air jet nozzle 94 to ensure that the compressed air can blow towards the complex parts inside the mold shell at an appropriate angle; since the air jet nozzles 94 at the end of the pipeline 93 are symmetrically distributed in a Y shape, the inside of the mold shell can be blown more comprehensively to blow out the remaining wax liquid;

[0054] In addition, the ultrasonic transducer 92 in the ultrasonic dewaxing tank 91 on the tray 3 starts to work under the control of the controller, generating high-frequency ultrasonic waves, accelerating the melting of the wax mold and the separation of the wax liquid from the mold shell, and assisting the dewaxing process to be more efficient; after dewaxing is completed, the hollow mold shell is taken out through the discharge port and the automatic sealing door at the top of the tank body 1 and placed in a high-temperature furnace for roasting to improve the strength and air permeability of the mold shell.

[0055] In the present invention, on the one hand, the rotating design of the tray 3 makes the shell heated more uniformly during the heating process, avoiding the problem of uneven melting of the wax mold caused by local temperature differences and accelerating the overall dewaxing speed. At the same time, the ultrasonic waves generated by the ultrasonic dewaxing tank 91 can destroy the adhesion between the wax liquid and the shell, making it easier for the wax liquid to flow out of the shell. The air compressor cooperates with the adjustable-angle air nozzle 94 to blow air at the complex parts inside the shell, effectively removing the residual wax liquid and further improving the dewaxing efficiency.

[0056] On the other hand, the liquid level sensor monitors the height of the wax liquid in real time, and the controller precisely controls the operation of the lifting drive module 965 and the air compressor according to the liquid level situation, ensuring that the pipeline 93 enters and exits the shell at the appropriate time and the air is blown into the shell at the appropriate time, guaranteeing the accuracy and stability of the dewaxing process. Moreover, the air nozzles 94 symmetrically distributed in a Y shape at the end of the pipeline 93 can cover a wider area inside the shell, enabling the compressed air to act evenly on the inside of the shell, reducing wax liquid residue and improving the dewaxing quality.

[0057] The lifting drive module 965 includes: a floating ball 9651 arranged in the wax liquid collection tank 6, a connecting rod 9652 fixed to the top of the floating ball 9651, the other end of the connecting rod 9652 is fixed with an inclined block, the inclined block is slidably installed on the inner wall of the wax liquid collection tank 6 in a limited manner, the inclined block is in contact with a rack 9653 on one side, the rack 9653 is slidably installed on the inner wall of the wax liquid collection tank 6 in a limited manner, and a return spring is arranged on the side of the rack 9653 away from the inclined block. The rack 9653 meshes with a gear 9654, the gear 9654 is coaxially fixed to the bottom end of a lead screw 9655, the lead screw 9655 is in screw drive connection with a slider 963, and the lead screw 951 is rotatably installed on a lifting bracket 961. A limiting block 967 is arranged on the inner wall of the wax liquid collection tank 6, and the distance between the limiting block 967 and the bottom wall of the lower wax liquid collection tank 6 serves as the moving space of the floating ball 9651.

[0058] The lifting drive module 965 includes: an electric push rod or a hydraulic cylinder. The air compressor is electrically connected to a liquid level switch, and the liquid level switch is electrically connected to the liquid level sensor.

[0059] As one embodiment of the lifting drive module 965, the lifting drive module 965 is a mechanical structure composed of a floating ball 9651, a connecting rod 9652, a rack 9653, a gear 9654, and a lead screw 9655. As the height of the wax liquid rises, the floating ball 9651 rises, driving the connecting rod 9652 and the rack 9653 to move upward. The meshing of the rack 9653 and the gear 9654 causes the gear 9654 to rotate, thereby driving the lead screw 9655 to rotate. Through the screw drive between the lead screw 9655 and the slider 963, the slider 963 descends along the guide rail 962, driving the mounting plate 964 and the pipeline 93 to descend, and enabling the pipeline 93 to enter the inside of the shell.

[0060] As another embodiment, the lifting drive module 965 is an electric push rod or a hydraulic cylinder, and the controller directly controls its movement to realize the descent of the pipeline 93.

[0061] The lifting drive module 965 can either adopt a mechanical structure or an electric push rod or a hydraulic cylinder, and users can make a choice according to actual requirements and working environments, which enhances the applicability and flexibility of the equipment.

[0062] The above has described in detail an embodiment of the present invention, but the content described is only a preferred embodiment of the present invention and cannot be considered as used to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. Precision casting process of stainless steel impeller for nuclear power, characterized in that: The steps include: S1, using the investment casting process to press the wax model, and connecting the single wax model into a tree-like structure through wax rods; S2, coating the wax mold with refractory material, and after drying, dewaxing the shell with a dewaxing device to obtain a hollow shell, and then placing the shell in a high-temperature furnace for baking; S3. Select duplex stainless steel material and melt it in an electric furnace, heat the molten steel to a predetermined pouring temperature, and pour it into the mold shell by bottom pouring or side pouring; S4: After the shell is naturally cooled, the shell is removed to obtain the impeller and then solution treatment is performed; S5. Remove the impeller surface and internal residues by sandblasting and shot blasting, and perform flaw detection using non-destructive testing technology; The dewaxing equipment used in S2 includes: a controller and a tank body, a rotating motor is arranged in the tank body, a tray is arranged at the output end of the rotating motor, a plurality of electric slide rails are arranged on the tray, and a fixing clamp is installed on the electric slide rail; a feed port and a discharge port are opened on the top of the tank body, and both the feed port and the discharge port are equipped with automatic sealing doors; a wax liquid collecting tank is connected to the bottom of the tank body, and a liquid level sensor is arranged in the wax liquid collecting tank; a heating chamber is arranged on the inner wall of the tank body, a heating element is arranged in the heating chamber, and the outer wall of the tank body is wrapped with heat insulation material.

2. The precision casting process of stainless steel impeller for nuclear power according to claim 1, characterized in that: The dewaxing equipment also includes: an auxiliary dewaxing mechanism; The auxiliary dewaxing mechanism includes: an ultrasonic dewaxing tank and an air compressor. The ultrasonic dewaxing tank is arranged on a tray, and a plurality of ultrasonic transducers are evenly distributed inside the ultrasonic dewaxing tank; the air compressor is installed on the outside of the tank body, and the air compressor is connected to the inside of the shell through a pipeline, and an air nozzle with an adjustable angle is installed at the end of the pipeline.

3. The precision casting process of stainless steel impeller for nuclear power according to claim 2, characterized in that: An angle adjustment component is provided at the end of the pipe, and the angle adjustment component is used to adjust the angle of the air jet; The angle adjustment assembly includes a screw rod, which is rotatably installed on the end of the pipeline. A ring capable of spiral motion is sleeved on the screw rod, and a nozzle is fixed on the ring. The nozzle and the pipeline are softly connected by a hose. The end of the screw rod is connected to a drive motor, and the drive motor is installed on the end of the pipeline.

4. The precision casting process for stainless steel impeller for nuclear power according to claim 3, characterized in that: The auxiliary dewaxing mechanism also includes: a lifting component, which is used to enable the pipeline to enter and exit the mold shell; the lifting component includes: A lifting bracket installed on the top of the tank body, the lifting bracket includes a vertically arranged guide rail and a slider that can slide up and down along the guide rail, a horizontal mounting plate is fixedly connected to the slider, and the pipeline is fixedly mounted on the mounting plate; The lifting drive module is connected to the slider in a transmission manner and is used to drive the slider to move up and down along the guide rail, thereby driving the pipeline to move up and down so that the pipeline can enter and exit the mold shell.

5. The precision casting process of stainless steel impeller for nuclear power according to claim 4, characterized in that: The lifting drive module includes: a float arranged in the wax collection tank, a connecting rod fixed on the top of the float, an inclined block fixed on the other end of the connecting rod, the inclined block limited sliding installation on the tank wall of the wax collection tank, the inclined block contacts with a rack on one side, the rack limited sliding installation on the tank wall of the wax collection tank, and a reset spring is arranged on the side of the rack away from the inclined block, and the rack is meshed with the gear, the gear is coaxially fixed to the bottom end of the screw, the screw is connected to the slider in a spiral transmission, and the screw is rotatably installed on the lifting bracket.

6. The precision casting process for stainless steel impeller for nuclear power according to claim 4 or 5, characterized in that: The lifting drive module includes: an electric push rod or a hydraulic cylinder, an air compressor electrically connected to a liquid level switch, and a liquid level switch electrically connected to a liquid level sensor; The controller is electrically connected to the liquid level sensor and the lifting drive module; when the liquid level sensor detects that the wax liquid height in the wax liquid collecting tank reaches a first set value, and the second set value is greater than the first set value, the controller controls the lifting drive module to move and lower the pipeline into the shell; when the liquid level sensor detects that the wax liquid height in the wax liquid collecting tank reaches the first set value, the controller controls the lifting drive module to lower the pipeline while the air compressor starts working.

7. The precision casting process for stainless steel impeller for nuclear power according to claim 5, characterized in that: A limiting block is arranged on the wall of the wax liquid collecting tank, and the distance between the limiting block and the bottom wall of the lower wax liquid collecting tank serves as the activity space of the floating ball.

8. The precision casting process for stainless steel impeller for nuclear power according to claim 7, characterized in that: Two air jets are installed at the end of the pipeline and are symmetrically distributed in a Y shape.

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