Manufacturing method of pump shell structure of shield pump

Abstract

The invention discloses a manufacturing method of a pump shell structure of a shield pump, and relates to the field of pump shell structures, the pump shell structure comprises a pressure-bearing shell and an inner flow channel assembly embedded in the pressure-bearing shell; the method comprises the steps that S1, a pressure-bearing shell and an inner flow channel assembly are produced according to the design size; s2, cutting the inner runner assembly into a plurality of runner blocks, wherein the runner blocks comprise a first runner block, a second runner block and a third runner block; s3, the first flow channel block and the second flow channel block are placed in the pressure bearing shell, and the positions of the first flow channel block and the second flow channel block are adjusted so that flow channel outlets can be aligned with the pump shell outlet; s4, embedding the third flow channel block into the pressure-bearing shell, and adjusting the position again to enable the outlet of the flow channel to be aligned with the outlet of the pump shell; and S5, all the runner blocks and the pressure-bearing shell are welded and fixed, and manufacturing of the pump shell structure of the shield pump is completed. The integrity of the pressure boundary of the pump shell is guaranteed, meanwhile, a simple and convenient machining and manufacturing method is provided, the volute type flow channel is embedded into the pressure bearing shell, and the purpose of improving the hydraulic efficiency of the shield pump is achieved.

Description

Technical Field

[0001] This invention relates to the field of pump casing structure, and in particular to a method for manufacturing a pump casing structure for a canned motor pump. Background Technology

[0002] A canned motor pump, consisting of a pump body and a motor, is essentially a pressure vessel. It is commonly used in high-temperature and high-pressure environments, such as for transporting toxic and hazardous liquids in the chemical and pharmaceutical industries, fuel loading before rocket launches, nuclear-grade canned motor pumps in nuclear power plants, air conditioning circulating water systems, and ground-source heat pumps for heating and cooling circulating water systems. The entire canned motor pump (pressure vessel) is filled with the high-temperature, high-pressure medium, requiring the maintenance of the integrity of the entire pump casing boundary.

[0003] For canned motor pump casings used in high-temperature and high-pressure environments, the following existing technologies are used to ensure the integrity of the pressure boundary: 1. Directly using a rotary pump casing: This involves directly designing the canned motor pump casing as a rotary type. However, rotary pump casings have lower energy recovery efficiency, leading to reduced hydraulic efficiency and consequently a further decrease in the overall efficiency of the canned motor pump. In the chemical canned motor pump industry, pump efficiency directly impacts a company's economic benefits; therefore, improving the overall efficiency of canned motor pumps is essential.

[0004] 2. Pump casing with volute type: The volute type pump casing is directly machined, but because the volute type pump casing has a gradually changing circumferential cross section, it is difficult to process while ensuring the integrity of the pump casing. In addition, the volute is located in special positions such as partitions, and the processing technology is very difficult or even impossible.

[0005] In summary, current canned motor pump casings, while meeting the requirement of ensuring pressure boundary integrity, suffer from drawbacks such as low efficiency and manufacturing difficulties. Therefore, a new canned motor pump casing and its manufacturing method are needed. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned problems by providing a method for manufacturing the pump casing structure of a canned motor pump. This method ensures the integrity of the pump casing pressure boundary while providing a simple manufacturing process that embeds a volute-type flow channel within the pressure-bearing casing, thereby improving the hydraulic efficiency of the canned motor pump.

[0007] The technical solution adopted in this invention is as follows: A method for manufacturing a pump casing structure for a canned motor pump, the pump casing structure comprising a pressure-bearing shell and an inner flow channel assembly, wherein the pressure-bearing shell has an annular inner cavity, and the size of the inner cavity matches the outer dimensions of the inner flow channel assembly, the inner flow channel assembly is installed inside the pressure-bearing shell and fixedly connected to the inner wall of the pressure-bearing shell; the pressure-bearing shell has a pump casing inlet and a pump casing outlet communicating with the inner cavity, the inner flow channel assembly has a volute-type flow channel, the volute-type flow channel having a flow channel inlet and a flow channel outlet, the flow channel inlet being aligned and communicating with the pump casing inlet, and the flow channel outlet being aligned and communicating with the pump casing outlet; comprising the following steps: S1: Produce the pressure shell and internal flow channel assembly according to the design dimensions; S2: The internal flow channel assembly is divided into multiple flow channel blocks, including a first flow channel block, a second flow channel block, and a third flow channel block; There are: The two side lines of the first flow channel block are collinear with the center of the inner flow channel assembly; the center of the inner flow channel assembly is on the midline of the third flow channel block, and the two side lines of the third flow channel block are parallel to the midline of the third flow channel block; one side of the second flow channel block matches the side of the third flow channel block, and the other side matches the side of the first flow channel block. S3: Place the first flow channel block and the second flow channel block into the inner cavity according to the arrangement before cutting, and adjust their positions so that the flow channel outlet is aligned with the pump casing outlet. S4: Then embed the third flow channel block into the inner cavity according to the arrangement before cutting, and adjust its position again so that the flow channel outlet is aligned with the pump casing outlet. S5: Weld and fix all flow channel blocks to the pressure-bearing shell to complete the manufacturing of the pump casing structure of the canned pump.

[0008] Furthermore, in step S1, the inner flow channel assembly is integrally molded during production.

[0009] Furthermore, in step S1, when producing the inner flow channel assembly, the upper and lower parts of the inner flow channel are produced first, and then the upper and lower parts are aligned and welded together to complete the overall production of the inner flow channel assembly.

[0010] Furthermore, in step S1, the pressure-bearing shell is integrally formed during production.

[0011] Furthermore, in step S1, during the production of the pressure shell, a first mounting opening is machined on the mounting surface of the pressure shell that mates with the motor, and the axis of the first mounting opening is collinear with the axis of the inner cavity.

[0012] Furthermore, in steps S3 and S4, the flow channel block is inserted into the inner cavity from the first mounting port.

[0013] Furthermore, in step S2, when cutting the inner flow channel assembly to manufacture the flow channel blocks, it is ensured that the geometric dimensions of each flow channel block are smaller than the diameter of the first mounting port.

[0014] Furthermore, in step S5, when welding and fixing the flow channel block, the flow channel block is welded and fixed to the first mounting port and the pump housing inlet, so that both end faces of the flow channel block are fixed.

[0015] Furthermore, in step S5, after welding is completed, the transition between the flow channel outlet and the pump casing outlet is smoothed by grinding.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. By manufacturing a nested volute structure, this invention can ensure the integrity of the pressure boundary and realize the use of the volute-shaped internal flow channel, which greatly improves the pressure energy recovery of the canned pump, thereby improving the overall hydraulic efficiency of the canned pump and thus improving the efficiency of the entire canned pump, resulting in significant economic benefits. 2. This invention reduces assembly difficulty and facilitates manufacturing by making the inner flow channel assembly consist of multiple flow channel blocks and embedding the inner flow channel assembly into the pressure-bearing sleeve. Attached Figure Description

[0017] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure along the AA direction; Figure 3 This is a schematic diagram of the structure of the pressure-bearing shell provided by the present invention; Figure 4 This is a schematic diagram of the internal flow channel assembly provided by the present invention; Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure in the middle BB direction; Figure 6 This is a schematic diagram showing the cutting positions during the generation of the flow channel block; Figure 7 This is a schematic diagram showing the relative positional distribution of the flow channel blocks; In the diagram, the markings are: 1-pressure bearing shell; 11-first mounting port; 12-pump casing inlet; 13-pump casing outlet; 14-inner cavity; 2-inner flow channel assembly; 201-stop groove; 202-stop platform; 21-second mounting port; 22-flow channel inlet; 23-flow channel outlet; 24-volute flow channel; 25-upper part; 26-lower part; 27-third flow channel block; 28-second flow channel block; 29-first flow channel block; 291-flow channel block one; 292-flow channel block two; 293-flow channel block three. Detailed Implementation

[0018] In the description of this specification, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0019] Furthermore, the use of terms such as "horizontal" or "vertical" in this specification does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0020] In the description of this specification, it should also be noted that, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” should be interpreted broadly. For example, a link can be a fixed link, a detachable link, or an integral link; it can be a mechanical link or an electrical link; it can be a direct link or an indirect link through an intermediate medium; it can be a connection within two components.

[0021] Example 1 like Figures 1-7 As shown, a canned motor pump casing structure includes a pressure-bearing shell 1 and an inner flow channel assembly 2. The pressure-bearing shell 1 has an annular inner cavity 14, and the dimensions of the inner cavity 14 match the outer dimensions of the inner flow channel assembly 2. The inner flow channel assembly 2 is installed inside the pressure-bearing shell 1 and is fixedly connected to the inner wall of the pressure-bearing shell 1. The pressure-bearing shell 1 has a pump casing inlet 12 and a pump casing outlet 13 communicating with the inner cavity 14. The inner flow channel assembly 2 has a volute-type flow channel 24, which has a flow channel inlet 22 and a flow channel outlet 23. The flow channel inlet 22 is aligned and communicates with the pump casing inlet 12, and the flow channel outlet 23 is aligned and communicates with the pump casing outlet 13.

[0022] In this embodiment, the pressure-bearing shell 1 is manufactured as a single piece to ensure its integrity. The inner cavity 14 of the annular structure inside the pressure-bearing shell 1 ensures that the pressure on the pressure-bearing shell 1 is evenly distributed, thereby further improving the pressure-bearing capacity of the pressure-bearing shell 1 and ensuring the integrity of the pressure boundary of the pump shell structure.

[0023] In this embodiment, the inner flow channel assembly 2 is nested inside the pressure-bearing shell 1. Since the pressure-bearing shell 1 ensures the integrity of the pressure boundary of the pump shell structure, the inner flow channel does not need to ensure the integrity of the pressure boundary. That is, the inner flow channel can adopt a spliced ​​volute flow channel 24. The pressure energy recovery performance is ensured by the inner flow channel assembly 2 with the volute flow channel 24, so as to improve the overall hydraulic efficiency and thus improve the efficiency of the entire canned pump.

[0024] In this embodiment, the pressure shell 1 has a first mounting port 11 for mounting the impeller, and the first mounting port 11 is connected to the inner cavity 14; the inner flow channel assembly 2 has a second mounting port 21 for mounting the impeller, and the second mounting port 21 is connected to the volute flow channel 24. When mounting the impeller, the impeller can be installed in the volute flow channel 24 after passing through the first mounting port 11 and the second mounting port 21.

[0025] Furthermore, the first mounting port 11 is located on the mounting surface of the pressure shell 1 that mates with the motor. Specifically, the pressure shell 1 has two parallel end faces, one of which has a pump inlet 12 and the other serves as the mounting surface with the first mounting port 11. If feasible, the axes of the first mounting port 11, the inner cavity 14, and the pump inlet 12 are all collinear.

[0026] Furthermore, the second mounting port 21 is opened on the end face of the inner flow channel assembly 2 near the mounting surface, that is, the second mounting port 21 is aligned and connected with the first mounting port 11, and its diameter can be smaller than the diameter of the first mounting port 11; the inner flow channel assembly 2 also has two parallel end faces, one end face is opened with the inner flow channel inlet 22, and the other end face is opened with the mounting port. Feasibly, the axes of the first mounting port 11, the second mounting port 21, the volute flow channel 24 and the flow channel inlet 22 are all collinear, so that after the impeller is installed in the volute flow channel 24, the axis of the impeller can be collinear with the axis of the inner flow channel assembly 2, thus ensuring hydraulic performance.

[0027] Example 2 like Figures 1-7 As shown, a method for manufacturing a canned motor pump casing structure, comprising the following steps: S1: Produce the pressure-bearing shell 1 and the inner flow channel assembly 2 according to the design dimensions; wherein, the pressure-bearing shell 1 is produced using a one-piece molding method to ensure the integrity of the pressure-bearing shell 1, thereby ensuring the pressure-bearing capacity of the pressure-bearing shell 1 and meeting the requirements for the integrity of the pressure boundary of the pressure-bearing shell 1; it should be noted that the one-piece molding production method of the pressure-bearing shell 1 is a mature technology in the field, such as the rotary pump shell production method mentioned in the background art, which is also a one-piece molding production method; for the production of the inner flow channel assembly 2, it can be produced using a one-piece molding method or a split molding method; for the one-piece molding production method of the inner flow channel assembly 2, the volute-type pump shell production method mentioned in the background art can be used as a reference, which is a mature technology in the field, but as described in the background art, its processing is difficult; therefore, based on this canned pump The pressure boundary of the pump casing structure is borne by the pressure-bearing shell 1, while the inner flow channel assembly 2 does not have the function of bearing the pressure boundary. Therefore, this method proposes to produce the inner flow channel assembly 2 using a split molding production method. Specifically, the mid-plane of the generatrix of the inner flow channel assembly 2 is cut off, so that the inner flow channel assembly 2 is divided into an upper part 25 and a lower part 26. The upper part 25 and the lower part 26 are produced first, and then the upper part 25 and the lower part 26 are aligned and welded together to complete the overall manufacturing of the inner flow channel assembly 2. For this method, it is only necessary to align the corresponding positions when welding and assembling the upper part 25 and the lower part 26 (including aligning the center line of the upper part 25 with the center line of the lower part 26, and aligning the positions of the flow channel outlet 23 on the upper part 25 and the lower part 26) to maintain the integrity of the volute flow channel 24 and to prevent circumferential misalignment and deformation of the inner flow channel assembly 2.

[0028] Regarding the alignment of the corresponding positions described above, where: Regarding the alignment of the center line of the upper part 25 with the center line of the lower part 26, an annular stop groove 201 can be opened on the lower part 26, and the center line of the annular stop groove 201 is collinear with the center line of the lower part 26. A stop platform 202 matching the size and position of the stop groove 201 is set on the upper part 25, and the center line of the stop platform 202 is collinear with the center line of the upper part 25. When aligning, it is only necessary for the stop platform 202 to cooperate with the stop groove 201 to achieve the alignment of the center line of the upper part 25 with the center line of the lower part 26. Regarding the alignment of the flow channel outlet 23 positions on the upper part 25 and the lower part 26, the circumferential position can be adjusted after the center line of the upper part 25 is aligned with the center line of the lower part 26, thus aligning the flow channel outlet 23 positions on the upper part 25 and the lower part 26.

[0029] S2: Similarly, based on the pump casing structure of this shielded pump, the pressure boundary is borne by the pressure-bearing shell 1, while the inner flow channel assembly 2 does not have the function of bearing the pressure boundary. Therefore, the inner flow channel assembly 2 can be cut into multiple flow channel blocks to facilitate the embedded installation of the inner flow channel assembly 2 within the pressure-bearing shell 1. It is precisely because of this embedded structure that the pressure boundary is borne by the pressure-bearing shell 1, and the inner flow channel assembly 2 does not bear the pressure boundary. The multiple flow channel blocks include a first flow channel block 29, a second flow channel block 28, and a third flow channel block 27; There are: like Figure 6 As shown, the two side lines of the first flow channel block 29 are collinear with the center of the inner flow channel assembly 2; the center of the inner flow channel assembly 2 lies on the midline of the third flow channel block 27, and the two side lines of the third flow channel block 27 are parallel to the midline of the third flow channel block 27; one side of the second flow channel block 28 matches the side of the third flow channel block 27, and the other side matches the side of the first flow channel block 29; it should be noted that the conventional cutting method involves cutting the flow channel blocks into the same shape. This method, compared to that, is as follows: If all flow channel blocks are set to the same shape, i.e., the two side lines of all flow channel blocks are collinear with the center of the inner flow channel assembly 2, the following situation will occur when installing the last or last few flow channel blocks. Because these flow channel blocks are fan-shaped, and the already installed flow channel blocks occupy the cavity space, the inner dimension of the inner flow channel assembly 2 is smaller than the outer dimension, causing the already installed flow channel blocks to occupy part of the cross-sectional dimension of the first mounting hole. Furthermore, the remaining space is insufficient to fit the fan-shaped flow channel block into the inner cavity 14. Therefore, the last or last few flow channel blocks cannot pass through. Effective assembly is achieved through the first mounting hole. For this purpose, a third flow channel block 27 and a second flow channel block 28 are specially designed. The second flow channel block 28 has a structure due to the third flow channel block 27. Its main effect is that the third flow channel block 27 is a rectangular structure rather than a fan-shaped structure. When it is assembled into the inner flow channel assembly 2 in the inner cavity 14, it can leave a rectangular notch, which can effectively put the third flow channel block 27 into the inner cavity 14 to complete the assembly. Therefore, the assembly sequence of the flow channel blocks is to assemble the first flow channel block 29 and the second flow channel block 28 first, and then assemble the third flow channel block 27 last, to ensure that the embedded assembly can be effectively implemented.

[0030] Taking the cutting of a certain internal flow channel assembly 2 as an example, such as Figure 7As shown, using the line forming an angle β between the center of the flow channel outlet 23 and the center of the inner flow channel assembly 2 as the baseline, a total of 8 flow channel blocks are cut. Among them, one flow channel block 1 291, two flow channel blocks 292, and two flow channel blocks 293 belong to the first flow channel block 29. The flow channel outlet 23 is located inside the flow channel block 1 291, and the baseline is on the angle bisector of the angle formed by the two sides, so as not to damage the integrity of the flow channel outlet 23. Preferably, the flow channel block 1 The included angle formed by the two sides of 291 is α1; the included angle formed by the two sides of flow channel block 292 is α2, adjacent to flow channel block 291; the included angle formed by the two sides of flow channel block 293 is α3, adjacent to flow channel block 292; the two sides of the third flow channel block 27 are parallel to the baseline, a certain distance d apart, and are positioned directly opposite flow channel block 291; the second flow channel block 28 is located between the third flow channel block 27 and flow channel block 293.

[0031] S3: Place the first flow channel block 29 and the second flow channel block 28 into the inner cavity 14 according to the arrangement before cutting, and adjust their positions so that the flow channel outlet 23 is aligned with the pump housing outlet 13. Specifically, first place the first flow channel block 291, the second flow channel block 292 and the third flow channel block 293, and then place the second flow channel block 28. The alignment of the flow channel outlet 23 with the pump housing outlet 13 is to roughly determine the position of the flow channel outlet 23, so as to avoid the situation that the flow channel outlet 23 cannot be aligned with the pump housing outlet 13 due to the difficulty in adjusting the position of the flow channel outlet 23 after the third flow channel block 27 is inserted.

[0032] S4: Then, the third flow channel block 27 is embedded into the inner cavity 14 according to the arrangement before cutting, and the position is adjusted again so that the flow channel outlet 23 is aligned with the pump casing outlet 13. Since the position adjustment was carried out in step S3, the amount of misalignment between the flow channel outlet 23 and the pump casing outlet 13 caused by embedding the third flow channel block 27 is not large, so it is relatively easy to adjust the flow channel outlet 23 again. This provides an effective guarantee for the alignment of the flow channel outlet 23 and the pump casing outlet 13.

[0033] It should be noted that during step S1, when the pressure shell 1 is manufactured, a first mounting port 11 is machined on the mounting surface of the pressure shell 1 that mates with the motor. The axis of the first mounting port 11 is collinear with the axis of the inner cavity 14. The first mounting port 11 serves as both the inlet for the impeller and the inlet for the flow channel block. Thus, the flow channel block in steps S3 and S4 is inserted into the inner cavity 14 through the first mounting port 11. Therefore, in step S2, when the inner flow channel assembly 2 is cut to manufacture the flow channel block, the geometric dimensions of each flow channel block are ensured to be smaller than the diameter of the first mounting port 11, so that the flow channel block can be inserted into the inner cavity 14.

[0034] S5: Weld all flow channel blocks to the pressure shell 1 to complete the manufacturing of the pump shell structure of the canned pump; when welding and fixing the flow channel blocks, weld and fix the flow channel blocks to the first mounting port 11 and the pump shell inlet 12 to ensure that both end faces of the flow channel blocks are fixed, thereby improving the stability of the fixed position of the flow channel blocks; after welding, the transition between the flow channel outlet 23 and the pump shell outlet 13 is smoothed by grinding. This step is performed after welding so that even if the flow channel outlet 23 and the pump shell outlet 13 are misaligned during welding, they can be adjusted. This is also an important step to ensure that the flow channel outlet 23 and the pump shell outlet 13 are aligned.

[0035] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for manufacturing a pump casing structure for a canned motor pump, the pump casing structure comprising a pressure-bearing shell (1) and an inner flow channel assembly (2), wherein the pressure-bearing shell (1) has an annular inner cavity (14), and the dimensions of the inner cavity (14) match the outer dimensions of the inner flow channel assembly (2), the inner flow channel assembly (2) is installed inside the pressure-bearing shell (1) and fixedly connected to the inner wall of the pressure-bearing shell (1); the pressure-bearing shell (1) has a pump casing inlet (12) and a pump casing outlet (13) communicating with the inner cavity (14), the inner flow channel assembly (2) has a volute-type flow channel (24), the volute-type flow channel (24) having a flow channel inlet (22) and a flow channel outlet (23), the flow channel inlet (22) being aligned and communicating with the pump casing inlet (12), and the flow channel outlet (23) being aligned and communicating with the pump casing outlet (13); characterized in that: Includes the following steps: S1: Produce the pressure shell (1) and the inner flow channel assembly (2) according to the design dimensions; S2: The inner flow channel assembly (2) is cut into multiple flow channel blocks, including a first flow channel block (29), a second flow channel block (28), and a third flow channel block (27); thus: The two side lines of the first flow channel block (29) are collinear with the center of the inner flow channel assembly (2); the center of the inner flow channel assembly (2) is on the midline of the third flow channel block (27), and the two side lines of the third flow channel block (27) are parallel to the midline of the third flow channel block (27); one side of the second flow channel block (28) matches the side of the third flow channel block (27), and the other side matches the side of the first flow channel block (29); S3: Place the first flow channel block (29) and the second flow channel block (28) into the inner cavity (14) according to the arrangement before cutting, and adjust the position so that the flow channel outlet (23) is aligned with the pump casing outlet (13); S4: Then embed the third flow channel block (27) into the inner cavity (14) according to the arrangement before cutting, and adjust the position again so that the flow channel outlet (23) is aligned with the pump casing outlet (13); S5: Weld all flow channel blocks to the pressure shell (1) to complete the manufacturing of the pump shell structure of the shielded pump.

2. The manufacturing method according to claim 1, characterized in that: In step S1, the inner flow channel assembly (2) is integrally formed during production.

3. The manufacturing method according to claim 1, characterized in that: In step S1, when producing the inner flow channel assembly (2), the upper part (25) and the lower part (26) of the inner flow channel are produced first, and then the upper part (25) and the lower part (26) are aligned and welded together to complete the overall production of the inner flow channel assembly (2).

4. The manufacturing method according to claim 1, characterized in that: In step S1, the pressure shell (1) is integrally formed during production.

5. The manufacturing method according to claim 1, characterized in that: In step S1, during the production of the pressure shell (1), a first mounting port (11) is machined on the mounting surface of the pressure shell (1) that cooperates with the motor. The axis of the first mounting port (11) is collinear with the axis of the inner cavity (14).

6. The manufacturing method according to claim 5, characterized in that: In steps S3 and S4, the flow channel block is inserted into the inner cavity (14) from the first installation port (11).

7. The manufacturing method according to claim 6, characterized in that: In step S2, when manufacturing flow channel blocks by cutting the inner flow channel assembly (2), ensure that the geometric dimensions of each flow channel block are smaller than the diameter of the first mounting port (11).

8. The manufacturing method according to claim 7, characterized in that: In step S5, when welding the flow channel block, the flow channel block is welded and fixed to the first mounting port (11) and the pump housing inlet (12) so that both end faces of the flow channel block are fixed.

9. The manufacturing method according to claim 1, characterized in that: In step S5, after welding is completed, the transition between the flow channel outlet (23) and the pump casing outlet (13) is smoothed by grinding.

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