CN114810609A - Multistage vane pump and multistage partial flow pump with special guide structure - Google Patents

Abstract

The invention belongs to a multi-stage vane pump with a special flow guide structure and a multi-stage partial flow pump with a special flow guide structure in fluid machinery, solves the problems of large hydraulic loss, heavy weight, large occupied space and unsatisfactory flow guide performance of the flow guide structure of the conventional multi-stage pump, and solves the design and manufacturing problems of pumps with low specific speed. Is characterized in that: the pump cover and the guide vane or the pump body are provided with part guide seats corresponding to the outer sides of the impellers, one or more spiral guide surfaces are arranged on the guide seats or the various guide seat assemblies and in a space formed by the inner sides of the guide seats and the cylindrical surfaces or the conical surfaces on the outer sides of the impellers, and the multiple single-stage assemblies are assembled into various multi-stage pumps. The fluid is mainly guided in a tangential flow mode, the structure of the guide vane can be called a tangential guide vane, and the guide vane is a guide vane with a special guide mode after a radial guide vane, a flow passage type guide vane and a space guide vane of a multi-stage vane pump. The device is mainly used in the chemical industry, the petrochemical industry and the like which need high pressure and in the occasions which need small and exquisite structure and light weight.

Description

Multistage vane pump and multistage partial flow pump with special guide structure

technical field

The invention belongs to a multistage pump in fluid machinery, and relates to a guide vane type multistage vane pump and a multistage partial flow pump.

Background technique

In the guide vane type multi-stage vane pump, especially in the guide vane type multi-stage centrifugal pump and the guide vane type multi-stage mixed flow pump, radial guide vanes are provided, including positive guide vanes, annular spaces or bends, The diversion structure of the anti-guide vane has problems such as excessive radial size and heavy weight. The velocity direction of the liquid needs to undergo two sharp turns from radial to axial, and then from axial to radial. The flow channel through the guide vane enters the inlet of the next stage impeller. There are large hydraulic losses such as liquid turns, collisions, and local vortices, and the ideal performance cannot be achieved.

In the multi-stage partial flow pump, such as the patent application of CN202110317417.0, since there is no flow guide structure, the flow guide performance will be affected to a certain extent.

The above-mentioned guide vane type multi-stage vane pump and multi-stage partial flow pump, hereinafter referred to as multi-stage pump, the following removes the positive guide vane and annular space, and only retains the radial guide vane of the reverse guide vane for short as the guide vane. The arc-shaped diffusion chamber of the multistage partial flow pump is referred to as the diffusion chamber for short, and the parts with the diffusion chamber are referred to as the pump body.

SUMMARY OF THE INVENTION

The purpose of the present invention is to design and provide a single-stage assembly of a multi-stage pump with a special flow-guiding structure that is simple in structure, easy to manufacture, improves flow-guiding performance, and reduces hydraulic loss. volume of the pump.

Another object of the present invention is to use multiple sets of the above single-stage components for assembly to develop and provide another type of multi-stage pump products with many special diversion structures, and to solve the problem of multi-stage pumps, especially low specific revolutions. Multistage pump design is cumbersome and difficult.

The former object of the present invention can be achieved by the following technical solutions: a multi-stage vane pump with a special flow guide structure and a multi-stage partial flow pump with a special flow guide structure, the single-stage components include: an impeller and its two sides parts, a pump cover, a guide The vane or the pump body is characterized in that a separate guide seat is arranged between the pump cover and the guide vane or the pump body corresponding to the outer side of the impeller blade, or the guide seat is arranged with the pump cover, guide vane or pump. One or more helical guide surfaces are arranged on the guide seat or the guide seat assembly, and in the space formed by the cylindrical surface or the conical surface formed by the inner side and the outer side of the impeller blade.

According to the above-mentioned multi-stage pump, the guide seat assembly may also include the following structures: (1) the guide seat and the pump cover are cast into one body; (2) the guide seat and the guide vane or the pump body are cast into one body; ( 3) The guide seat is cast into one body with the guide vane or pump body and the next stage pump cover; (4) The guide seat is cast into one with the guide vane or pump body, the next stage pump cover and the next stage guide seat; (5) The guide vane or pump body is cast into one with the next-stage pump cover and the next-stage guide seat.

According to the above-mentioned multi-stage pump, the end surface of the spiral guide surface can be connected with the bottom of the guide vane of the multi-stage vane pump or with the bottom of the diffusion chamber of the multi-stage partial flow pump; ; Or use a double-bevel fit joint.

According to the above-mentioned multi-stage pump, the helical guide surface can be formed by connecting positive helical surfaces with different leads, oblique helical surfaces, or oblique helical surfaces whose generatrix is a curve; It is composed of helical surfaces spaced in groups; or different combinations of the above-mentioned structures are used; the inner end of the cross section of the helical surface can also be provided with chamfers or/and with the guide seat or the outer wall of the guide seat assembly. Cast fillets.

According to the above-mentioned multi-stage pump, the impeller type of the multi-stage vane pump can be closed or semi-open; the impeller type of the multi-stage partial flow pump can be open, semi-open or between open and semi-open. or set a twisted blade surface at the outer circle of the blade.

According to the above-mentioned multistage pump, a boss can be arranged at the bottom of the pump cover of the multistage pump corresponding to the guide vane flow channel or at the flow channel of the diffusion chamber of the partial flow pump or/and a guide cone surface can be arranged at its corresponding impeller inlet; Or/and interstage seals can be provided at the guide vanes or the inner circumference of the pump.

According to the above-mentioned multi-stage pump, the throat portion of the partial-flow pump can be arranged behind the end surface of the spiral guide surface of the multi-stage partial-flow pump and in front of the diffusion chamber.

Another object of the present invention can be achieved by the following technical solutions: using multiple sets of the single-stage components described in any one of the above, combined with other spare parts, assembled into a multi-stage vane pump and a special guide structure with various special flow guide structures Multistage partial flow pump with flow structure. According to the above-mentioned multi-stage pump, the suction port of the impeller and the relevant parts of its corresponding parts can be close to the motor or other power output ends to form an inverted multi-stage pump which is opposite to the general multi-stage pump arrangement.

According to the above multi-stage pump, each set of single-stage components can be fastened by a plurality of tie rods; or mechanically compressed and fastened in the pump barrel; or one of the single-stage components can be compressed with the pump barrel or Other pump bases are welded into one.

Compared with the prior art, the beneficial effects of the present invention are:

Compared with the existing guide vane type multi-stage vane pump, the present invention sets the spiral guide surface, removes the positive guide vane and the annular space, avoids the hydraulic loss caused by the two sharp turns of the liquid flow, and has no original positive guide. The diameter and axial space occupied by the blade can also reduce the radial space occupied by the original annular space, and also reduce the weight. Compared with the multi-stage partial flow pump, the spiral guide surface is added, the guide performance is improved or improved, the hydraulic loss is reduced, and the liquid can be guided into the diffusion chamber in all directions and at every angle.

The diversion mode of the present invention mainly conducts diversion in a tangential flow mode, and its structure can be called a tangential, circumferential or axial guide vane. The guide vane of the new special guide structure after the space guide vane, the guide vane is smooth and efficient. It is especially suitable for multi-stage pumps with high speed, high pressure and small flow, because the placement angle of the impeller blades of this type of pump is very large, and the absolute velocity of the liquid flow is close to the circumferential velocity, that is, the tangential velocity, which requires tangential flow. diversion.

This kind of multi-stage pump is very difficult to design, and it is difficult to approximate it successively in calculation. Each pump needs to be designed and calculated separately, and it is difficult to achieve satisfactory results. The present invention avoids these problems and only adjusts the diameter of the impeller or/and the spiral diversion According to the width of the surface, different specifications of products can be obtained, and many products can be produced by using different types and sizes of impellers and spiral guide surfaces designed only with three simple parameters: helix angle, spiral guide surface width and flow channel inlet area. , which is equivalent to another major series of multi-stage pumps at present, breaking through the development situation of multi-stage pumps without progress for decades, and solving the cumbersome design of multi-stage pumps, especially low-speed multi-stage pumps.

At present, there is no multistage partial flow pump product on sale. The present invention realizes the design and manufacture of its product in a simple way, which will fill the gap of the multistage partial flow pump or the guide vane type multistage partial flow pump in the product classification. Possibly a globally unique breed.

Compared with the narrow and long flow channel of the guide vane of the existing multi-stage vane pump, which is difficult to cast, the present invention has a simple structure and is easy to manufacture.

The multi-stage pump of the present invention is also very simple to assemble, and can be assembled into various multi-stage pumps. It can be assembled and fastened by various methods, and the type arrangement is also flexible. For example, the inverted type structure can be used to improve operational reliability and reduce manufacturing costs.

The multi-stage pump of the present invention has simple structure, good heat dissipation performance, thin guide vanes and large impeller type variability, and satisfies the gas guide characteristics, that is, it can also transport other fluids other than liquids, such as gas, gas-liquid mixture and the like.

Description of drawings

Figure 1 is a multi-stage partial flow pump with a special diversion structure, and a schematic diagram of a spiral diversion surface is set in the assembly in which the diversion seat and the pump cover are cast into one;

Figure 2 is a schematic diagram of a multi-stage vane pump with a special guide structure, and a spiral guide surface is arranged in the assembly where the guide seat and the pump cover are cast into one;

Figure 3 is a schematic diagram of a multi-stage pump, where a spiral guide surface is arranged in the assembly in which the guide seat and the pump body are cast into one;

Figure 4 is a schematic diagram of a multi-stage pump, where a spiral guide surface is arranged in the assembly in which the guide seat, the pump body and the next-stage pump cover are cast into one piece;

Figure 5 is a schematic diagram of a multi-stage pump, where a spiral guide surface is provided in the assembly in which the guide seat and the pump body, the next-stage pump cover and the next-stage guide seat are cast into one piece;

Fig. 6 is a multi-stage pump, a schematic view of a spiral guide surface provided in the assembly in which the pump body, the pump cover of the next stage and the guide seat of the next stage are cast into one body;

Fig. 7 is a multi-stage pump, a three-dimensional schematic diagram of various spiral guide surfaces arranged in the guide seat;

Fig. 8 is the schematic diagram that the spiral guide surface of the multi-stage partial-flow pump with special guide structure is connected to the throat;

Figure 9 is a schematic diagram of the impeller provided with twisted blade surfaces on the outer circumference of its blades.

Detailed ways

The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

As shown in Figure 1, it is a multi-stage partial-flow pump with a special diversion structure. The impeller 7 is a partial-flow pump impeller, which is often dominated by radial straight blades. The part corresponding to the outer cylindrical surface of the blade is the guide seat 8. The guide seat 8 and the pump cover 10 in this figure have been cast into one piece to form a guide seat assembly.

As shown in Figure 2, it is a multi-stage vane pump with a special guide structure. The impeller 17 is a centrifugal or mixed-flow impeller, and its two sides have a pump cover 20 and guide vanes 14. The outer cylindrical surface of the blades of the impeller 17 corresponds to The part is the guide seat 18. The guide seat 18 and the pump cover 20 in this figure have been cast into one piece to form an assembly of the guide seat. If the blades of the mixed flow impeller 17 are inclined, an outer conical surface of the blades is formed. The blades of the centrifugal or mixed flow impeller 17 and the partial flow pump impeller 7 can also be set in an inclined state, that is, the diameter of the blade on one side of the rear cover is smaller than the diameter of the other end of the blade, and the outer side of the blade forms a conical surface. The impeller 17 can be sealed by the sealing plane 21 provided on the pump cover 20, and other impeller sealing rings such as cylindrical shape can also be provided for sealing.

One or more helical guides are arranged on the above-mentioned guide seats 8, 18 or their guide seat assemblies, as well as in the space formed by the inner side and the outer side of the blades of the impellers 7, 17 in the shape of a cylindrical surface or a conical surface. Surfaces 9 and 19, simply put: the spiral guide surface is set on the outside of the impeller. It can guide the liquid to the inlet 5 of the diffusion chamber of the partial flow pump of this stage or the inlet 15 of the guide vane flow channel of the multi-stage pump, and then guide it to the inlet of the impeller of the next stage through the diffusion chamber or the flow channel of the guide vane to complete the current stage. 's diversion. The structure of the diffusion chamber is detailed in the patent application of CN202110317417.0. The thickness of the spiral guide surfaces 9 and 19 is similar to the thickness of the guide seats 8 and 18 .

As shown in FIG. 3 , the guide seat 8 and the pump body 4 or the guide seat 18 and the guide vane 14 are cast integrally to form the guide seat assembly 22 , on the guide seat assembly 22 , and the inner side thereof and the impeller 7 Or in the space formed by the cylindrical surface or the conical surface formed by the outer side of the blade of the impeller 17, one or more helical guide surfaces 23 are arranged, which and the starting point of the bottom 6 of the arc-shaped diffusion chamber of the partial flow pump or the bottom 16 of the guide vane can be cast into Integrated, and called the connection method of connection, the bottom surface of the flow channel is smoothly transitioned, and the liquid flow loss is further reduced. Other descriptions of this figure are described in Figures 1 and 2.

As shown in FIG. 4 , on the basis of the structure of FIG. 3 , the guide assembly 22 can also be cast integrally with the pump covers 2 and 12 of the next stage to form a guide seat assembly 24 , which can reduce the number of parts. The single-stage assembly has only two parts, the impeller 7 and the guide seat assembly 24 .

As shown in FIG. 5 , on the basis of the structure of FIG. 4 , the guide seat assembly 24 can also be cast integrally with the next stage guide seat 1 and 11 to form a guide seat assembly 26 , and a guide seat assembly 26 is arranged on it. Or multiple spiral guide surfaces 25, which are equivalent to the spiral guide surface 9, which can reduce the number of parts and improve the concentricity between the front and rear spiral guide surfaces 23 and 25, which is beneficial to improve product quality.

As shown in FIG. 6, referring to the structure of FIG. 1, the pump body 4 can be cast integrally with the next stage pump cover 2 and the next stage guide seat 1, or the guide vanes 14 can be integrated with the next stage pump cover 12 and the next stage The guide seat 11 is cast in one piece to become the guide seat assembly 27, and other descriptions are the same as above.

At the bottom of the pump covers 2, 10, 12, and 20 of each stage, the bosses 3 or 13 are arranged at the positions corresponding to the inlet 5 of the diffusion chamber and the other flow channels or the inlets 15 of the guide vane flow channels and the remaining flow channels, which can adjust the diffusion chamber. Or the area of the flow channel at the inlet of the guide vane, the height of the boss 3 or 13 can be changed on the remaining flow channels, and the dispersion of the flow channel can also be adjusted, which can meet the needs of products of similar specifications, improve the degree of generalization, or/and In the center position of the covers 2, 10, 12, and 20, a guide cone 28 is arranged at the corresponding inlet of the impellers 7 and 17, which can expand the flow area before the inlets of the impellers 7 and 17 and the smooth transition of the liquid flow, and at the same time, it can reduce part of the flow back to the liquid at the inlet of the impeller 7 of the pump, or/and set an interstage seal 29 at the center of the pump body 4 or guide vane 14 and each guide seat assembly, which can reduce interstage leakage and further improve volumetric efficiency. The space seal 29 can be made of high-performance stainless steel shell PTFE seal, cylindrical gap seal, oil seal, etc.

In the case of similar product specifications and performance, the impeller 17 and the sealing surface 21 in FIG. 2 can be used in the structure of FIG. 3 to FIG. 6, and the pump body 4 and its assemblies are replaced with guide vanes 14 and their assemblies. Or directly use the diffusion chamber of the partial flow pump to reduce speed and increase energy without replacing, so that the speed energy can be converted into pressure energy and smoothly enter the next stage impeller.

As shown in FIG. 7, one or more helical guide surfaces 9, 19 are arranged on the guide seats 8, 18, and in the space formed by the inner side 33 thereof and the cylindrical surface or the conical surface formed by the outer side of the impeller blade, which is similar to The spiral reinforcement rib on the inner wall of the cylinder can be a spiral guide surface formed by connecting spiral surfaces 31 and 32 of different leads. It can be a positive spiral surface, an oblique spiral surface or an oblique spiral surface with the generatrix as a curve; One or more short helical surfaces 30 are further arranged between the two helical surfaces 9 and 19 to form groups of long and short helical surfaces. The busbar is a straight positive helix, such as the tooth-shaped part of the square thread and the tread of the circular staircase. The above helical surfaces are formed when the helix and the axis on the outer cylindrical surface after the required clearance is added to the outer side of the impeller 7 or 17 blade is a wire. If the outer end of the impeller 7 or 17 blade is inclined, increase the required The helix and the axis on the outer conical surface after the clearance are formed when the wire is formed. The lead of the above-mentioned helix is equal to the lead of the helical guide surface, which is determined during product design. At the cross section of the helical surface, that is, at the corresponding position of the bus bar, the inner end of the helical surface can be provided with a chamfer, similar to the thinning guide vane, or/and the other end of the helical surface can be provided with a cast fillet, similar to the inclined helical surface with a curved bus bar and its specific function. Various combinations of the above-mentioned types can also be utilized.

The end surfaces of the spiral guide surfaces 9, 19 and 25 can be in contact with the bottom 6 of the diffusion chamber of the multi-stage partial flow pump, or the bottom 16 of the guide vane of the multi-stage vane pump; or both of the above can be made into inclined surfaces , the joint method of double bevel bonding; this can form one surface of the runner. Due to deviations in manufacturing and installation, a certain gap is allowed, and due to the motion inertia of the liquid, the flow can also be smoothly guided.

The inner diameter of the above-mentioned helical surface or its end point is the same as or similar to the inner diameter of the corresponding flow channel, and maintains the required clearance with the outer diameter of the corresponding impeller; the helical surface of the large pump can be manufactured separately and fastened by welding, inlay, etc., or different materials; the parts of its components can be made of metal or non-metal.

The blades of the impellers 7 and 17 are in an intersecting state with various helical guide surfaces in the radial projection, and the liquid flowing out of the upper half of the blades is guided mainly tangentially through the front of the helical guide surface, and the lower half of the blades is guided by the tangential direction. Under the action of the tangential force of the impeller rotation in the space between the reverse side of the spiral guide surface and the pump cover, part of the outflowing liquid also enters the front of the next spiral guide surface in a tangential flow form, so that each An angle, all directions, and all the liquid will be guided down through the spiral guide surface.

The number of blades of the above impellers 7 and 17 is greater than the number of the spiral guide surfaces 9, 19, 23 and 25. There are several blades on each spiral guide surface, and the liquid flowing out from the blades is subjected to the tangential force of the blades. In the early stage, the action of the liquid is tangential flow. When the liquid touches the inner side 33 of the guide bases 8 and 18, it will be subjected to its normal reaction force. After the two forces are combined, it becomes a circumferential force, so that the liquid flows in a circumferential direction, that is, a circular motion. , in the guide seat or its assembly, on the spiral guide surface, guide all the liquid down. Simply put: in the later stage, the liquid is moved in a circular motion under the action of the tangential force of the blade and the reaction force of the wall. These two flows of fluid have the least resistance. This diversion mode can be called tangential, circumferential or axial diversion mode. It is a special diversion mode and a special diversion structure, which has much less loss than radial guide vanes and improves the guiding efficiency of multi-stage pumps. flow performance.

The above-mentioned guide seats 8 and 18 have simple structure, convenient design, easy manufacture, excellent performance and strong versatility, and are suitable for mass production.

As shown in FIG. 8 , it is a multi-stage partial flow pump with a special guide structure. After the end point of the spiral guide surface 9, a throat part 34 of the partial flow pump connected to it can be set, and then connected to the inlet 5 of the diffusion chamber. This can improve the dimensional stability of the inlet flow channel of the diffusion chamber and also improve the performance stability of the multistage pump. The above structure can also be applied to a multi-stage vane pump.

As shown in Figure 9, the impeller of the multi-stage vane pump can be closed impeller 17 or semi-open; the impeller of the multi-stage partial flow pump can be open, semi-open, or between open and semi-open. The impeller 7 between the formulas; or a twisted blade surface 36 is arranged on the outer circumference of the blades of the impellers 7 and 17 .

Using the above-mentioned multiple sets of single-stage components, the multi-stage components of the multi-stage pump can be formed, and then other components can be used to assemble various multi-stage pump products. Multistage pumps with similar performance specifications do not need too many changes and do not need to be redesigned. It can adapt to various demands of high pressure, high speed, light weight and small volume.

For the above-mentioned multi-stage pump, the suction ports of the impellers 7 and 17 and the relevant parts of their corresponding parts, such as the guide cone surface 28 of the pump cover, the sealing plane 21, etc., can be close to the motor or other power output ends, and the structure is the same as that of the general pump. The multistage pump arrangement is the reverse of the inverted version of the multistage pump, such as the use of an inverted deep well pump. This can reduce the requirement of sealing performance between the multi-stage pump and the motor or other power, and can replace the high-pressure sealing device with a low-pressure sealing device, which can improve the reliability of the multi-stage pump operation and reduce the cost.

For the above-mentioned multi-stage pump, the radial and axial directions of the two adjacent parts can be positioned by the cylindrical surface of the outer wall and its end face, and the circumferential positioning can be through the bottom 6 of the diffusion chamber or the bottom 16 of the guide vane and the spiral guide. The end faces of the flow surfaces 9, 19, and 25 adopt the contacting method, or the joint method of double bevel fitting, which can be tightened by various mechanical methods, such as tightening by multiple tie rods; or threads, pins, etc. Tighten and fasten in the pump barrel 35; in maintenance-free products, one of the single-stage components can be welded into the pump barrel 35 or other pump bases after compression.

The specific embodiments described in the present invention are only to illustrate the spirit of the present invention, and modifications, substitutions, alterations, additions, etc. are made without departing from the principles of the present invention, which will not exceed the scope defined by the claims.

Claims (10)

1. Multistage vane pump with special diversion structure and multistage partial flow pump with special diversion structure, hereinafter referred to as multistage pump, its single-stage components include: impeller and its two side parts, pump cover, guide vane or pump body, It is characterized in that: between the pump cover and the guide vane or the pump body, a separate part guide seat corresponding to the outer side of the impeller blade is arranged, or the guide seat is arranged with the pump cover, the guide vane or the pump body combined with the guide seat. In the seat assembly, one or more helical guide surfaces are arranged on the guide seat or the guide seat assembly and in the space formed by the cylindrical surface or the conical surface formed by the inner side and the outer side of the impeller blade. 2. The multistage pump according to claim 1, wherein the guide seat assembly can further comprise the following structures: (1) the guide seat and the pump cover are cast into one body; (2) the guide seat and the pump cover are cast into one body; The guide vane or pump body is cast into one body; (3) The guide seat is cast into one body with the guide vane or pump body and the next stage pump cover; (4) The guide seat is cast with the guide vane or pump body, the next stage pump cover and The next-stage guide seat is cast into one body; (5) the guide vane or pump body is cast into one with the next-stage pump cover and the next-stage guide seat. 3. The multistage pump according to claim 1 or 2, wherein the end surface of the helical guide surface can be connected to the bottom of the guide vane of the multistage vane pump or the bottom of the arc-shaped diffusion chamber of the multistage partial flow pump. Use the connection method of connection; or use the connection method of contact; or adopt the connection method of double bevel fit. 4. The multistage pump according to claim 3, characterized in that: the helical guide surface can be formed by connecting positive helical surfaces of different leads, oblique helical surfaces or oblique helical surfaces whose generatrix is a curve; or the described The helical guide surface can be composed of long helical surfaces or helical surfaces with long and short intervals; or different combinations of the above-mentioned structures; Or a casting fillet is set at the connection between the outer walls of the guide seat assembly. 5. The multistage pump according to claim 4, wherein the impeller type of the multistage vane pump can be closed or semi-open; the impeller type of the multistage partial flow pump can be open or semi-open. Or between the open type and the semi-open type; or set a twisted blade surface at the outer circle of the blade. 6. The multistage pump according to claim 5 is characterized in that: a boss can be set at the bottom of the pump cover of the multistage pump corresponding to the guide vane flow channel or at the flow channel of the partial flow pump diffusion chamber or/and can be set at the bottom of the pump cover. Corresponding to the inlet of the impeller, a guide cone is arranged; or/and an interstage seal can be arranged at the guide vane or the inner circle of the pump. 7 . The multistage pump according to claim 6 , wherein a throat portion of the partial flow pump can be arranged in front of the arc-shaped diffusion chamber after the end surface of the spiral guide surface of the multistage partial flow pump. 8 . 8. A multi-stage pump, characterized in that it comprises a plurality of single-stage assemblies of the multi-stage pump according to any one of the preceding claims 1 to 7. 9. The multistage pump according to claim 8, characterized in that: the suction port of the impeller and the relevant parts of its corresponding parts can be close to the motor or other power output ends, forming a multistage multistage pump of an inverted type opposite to the general multistage pump arrangement. stage pump. 10. The multi-stage pump according to claim 8 or 9, characterized in that: each set of single-stage components can be fastened by a plurality of tie rods; or mechanically compressed and fastened in the pump barrel; or single-stage components One of the parts is welded into one body with the pump barrel or other pump seat after pressing.

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