Centrifugal multiphase multiphase pump

Abstract

The invention provides a centrifugal multiphase multiphase pump which comprises a shell and an impeller, the shell is provided with a pump cavity for installing the impeller, the pump cavity is divided into a front cavity and a rear cavity by a rear cover plate of the impeller, the front cavity is a space, close to an inlet, in the pump cavity, and the rear cavity is a space, close to a driving end, in the pump cavity; the rear cover plate extends into the rear cavity, and part of blades in the impeller extend in the axial direction. A cylindrical wall surface is formed between the position of the original rear cover plate and the extended rear cover plate on the outer side of the hub of the impeller, and a cavity formed by the cylindrical wall surface and part of the axially extending blades enables a conveying medium to form through flow and circulating flow, so that the conveying efficiency of the gas-liquid two-phase medium is improved. The pump can be used for pumping liquid with a solid and gas mixture, the flow characteristic of the liquid is effectively improved through the impeller structure of the pump, and the transportation efficiency of the liquid with the gas mixture is remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of water pumps or two-phase medium mixed transportation, and in particular to a centrifugal multiphase mixed transportation pump. Background Art

[0002] The working principle of the centrifugal pump is based on the action of centrifugal force. When the pump shaft rotates, the impeller rotates with it. The liquid is affected by the centrifugal force and projects from the center point of the impeller to the periphery, enters the partition and flows to the outlet, and finally is discharged through the discharge pipe. In this process, the centrifugal force generated by the impeller and the required pressure difference make the liquid flow from the low-pressure area to the high-pressure area, thereby completing the liquid transportation. Inside the centrifugal pump, part of the fluid does not flow directly to the outlet after being pushed by the impeller, but forms a circulating flow, which is affected by the internal geometric structure and pressure distribution of the pump cavity and flows back to the impeller inlet or other parts of the pump. The circulating flow can increase the pump head and efficiency, but it may also increase the internal energy loss of the pump; the liquid that flows directly to the outlet under the impeller is called through flow, and the flow rate and speed of the through flow determine the delivery capacity and performance of the centrifugal pump. Channel impeller pumps are widely used in agricultural irrigation, chemical engineering, petroleum storage and transportation, marine engineering and other fields.

[0003] The prior art has disclosed an efficient and large-flow mining drainage pump. This invention reduces the hydraulic loss of the pump, reduces the radial load and axial load of the impeller, improves the stability of the pump operation, and improves the efficiency of pumping large-flow liquids. However, the researchers only used the ideal turbulence model as the medium for simulation experiments, so its application field is relatively narrow. The prior art also disclosed a slurry pump for pumping liquid with solid particles. This study explored the direction of improving the structure of the pump body under the influence of solid particles and emphasized the importance of wear resistance. Therefore, its applicable materials and processes are relatively strict.

[0004] Existing technologies are successfully used to pump ideal media or liquids containing thick materials, sludge, scum, etc. However, they are limited in their ability to expel gas accumulations (including air). Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a centrifugal multiphase mixed flow pump, which extends to the interior of the rear cavity through the rear cover plate, and some blades in the impeller extend axially. The resulting changes in the impeller structure and the differentiation of the chamber reduce the adverse effects of the air resistance caused by the low-pressure area, improve the self-priming ability generated by the low-pressure area in the middle of the circulating flow in the front cavity, control and reduce the occurrence of secondary reflux caused by the pressure difference, enhance the circulating flow generated in the front chamber between the liquid inlet and outlet, and improve the through-flow through the flow channel between the impeller blades in the rear chamber. It can be used to pump liquid with a mixture of solids and gases; its impeller structure effectively improves the flow characteristics of the liquid and significantly improves the transportation efficiency of the liquid with a gas mixture.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A centrifugal multiphase mixed pump comprises a casing and an impeller, wherein the casing has a pump chamber for installing an impeller, and the pump chamber is divided into a front chamber and a rear chamber by a rear cover plate of the impeller, wherein the front chamber is a space near the inlet in the pump chamber, and the rear chamber is a space near the driving end in the pump chamber; the rear cover plate extends to the inside of the rear chamber, and part of the blades in the impeller extend axially; the outer side of the hub of the impeller forms a cylindrical wall surface between the original rear cover plate position and the extended rear cover plate, and the chamber formed by the cylindrical wall surface and the blades extending axially partially causes the conveying medium to form a vortex or turbulence, which is used to improve the efficiency of gas-liquid two-phase medium conveying. The resulting changes in the impeller structure and the differentiation of the chamber reduce the adverse effects caused by the air resistance generated by the low-pressure area, improve the self-priming ability generated by the low-pressure area in the middle of the circulating flow in the front chamber, control and reduce the occurrence of secondary reflux caused by the pressure difference, enhance the circulating flow generated in the front chamber between the liquid inlet and outlet, and improve the through-flow through the flow channel between the impeller blades in the rear chamber.

[0008] Furthermore, some of the blades distributed at intervals in the impeller extend axially to form wide blades, one end of which extends to the vicinity of the inner wall surface of the front cavity; one end of the wide blade extending to the front cavity is provided with a wide blade leading edge with a folded edge to limit the circulation flow from radial to axial direction, thereby improving the head and efficiency. A gap is provided between the leading edge of the wide blade and the inner wall surface of the front cavity.

[0009] Furthermore, the axial extension distance of the wide blade is 25% to 75% of the axial length of the unextended blade.

[0010] Furthermore, the angle ɑ between the leading edge of the wide blade and the inner wall surface of the front cavity is in the range of 30° to 45°, so as to improve the flow of the liquid in the cavity.

[0011] Furthermore, a guide plate having a curvature close to that of the blade is provided between each wide blade and its adjacent unextended blade.

[0012] Furthermore, the length of the guide plate is equal to 25% to 40% of the length of the wide blade. Preferably, the length of the guide plate is approximately equal to 30% of the length of the wide blade.

[0013] Furthermore, two guide plates are provided between each of the wide blades and its adjacent unextended blade, one guide plate is located at the hub of the impeller, and the other guide plate is located at the cylindrical wall.

[0014] Furthermore, the cylindrical wall surface is in a conical shape, and the cone angle of the cylindrical wall surface is 2γ, wherein γ does not exceed 20 degrees.

[0015] Furthermore, the inner wall surface of the front cavity corresponding to the leading edge of the wide blade is provided with a spiral groove perpendicular to the impeller axis, and the cross-sectional shape of the groove is an isosceles triangle.

[0016] Furthermore, a plurality of guide holes are provided on the rear cover plate, and the guide holes have an inclination angle facing the edge of the impeller, which is used to improve the flow characteristics of the liquid in the cavity and improve the pumping efficiency. The value range of the inclination angle β is 25° to 45°.

[0017] The beneficial effects of the present invention are:

[0018] 1. The centrifugal multiphase mixed flow pump described in the present invention extends to the interior of the rear cavity through the rear cover plate, and some blades in the impeller extend axially. This novel arrangement and the resulting changes in the impeller structure and the differentiation of the chamber reduce the adverse effects of the air resistance caused by the low-pressure area, improve the self-priming ability generated by the low-pressure area in the middle of the circulating flow in the front cavity, control and reduce the occurrence of secondary reflux caused by the pressure difference, enhance the circulating flow generated in the front chamber between the liquid inlet and outlet, and improve the through-flow through the flow channel between the impeller blades in the rear chamber, which can effectively improve the efficiency of the centrifugal pump in conveying gas and liquid.

[0019] 2. The centrifugal multiphase mixed flow pump described in the present invention, on the basis of conventional blades, adds a guide plate to the impeller, extending part of the blades to the front cavity wall; under high-speed operation conditions, the extended blades can partially restrict the axial flow of the liquid and enhance the through-flow, and the guide plate can improve the circulation characteristics of the liquid flow, enhance the circulation flow, and reduce the generation of bubbles in the cavity; in fact, in this case, liquid molecules and solid molecules will collide with the leading edges of the blades and baffles, and it is worth noting that the benefits brought by the improved gas distribution far outweigh the disadvantages brought by the friction generated by the additional friction of the blades and baffles, thereby further improving the performance of the impeller.

[0020] 3. The centrifugal multiphase mixed flow pump described in the present invention leaves a certain gap between the rear surface of the rear cover plate and the inner surface of the rear wall of the casing to make room for the ridge structures on the two surfaces, wherein the ridge structure located on the rear surface of the rear cover plate is radially curved, while the ridge structure located on the inner surface of the rear wall of the casing is radially extended, thereby reducing the disc friction loss on the back of the impeller, reducing the liquid pressure in the rear chamber of the pump, and ensuring that the axial force acting on the impeller is partially balanced.

[0021] 4. The centrifugal multiphase mixed pump described in the present invention has a wide blade leading edge with a folded edge at one end of the wide blade, and the folded edge facing the rotation direction is designed with a certain inclination angle, which forms a cutting shape with the spiral groove on the front wall of the shell, so that larger solids entering the pump body chamber can be cut into particles, thereby improving the efficiency of pumping solids and liquids; at the same time, the folded edge structure can limit the circulation flow from radial to axial, increase the resistance of the fluid between the leading edge of the impeller wide blade and the front wall of the pump body due to the increase in the contact surface, and enhance the wear resistance of the blade against solid particles, thereby effectively increasing the head and improving efficiency.

[0022] 5. The centrifugal multiphase mixed flow pump described in the present invention is provided with six flow guide holes with a certain slope on the basis of a conventional rear cover plate. These flow guide holes can improve the flow characteristics of the liquid in the impeller cavity, thereby significantly improving the efficiency of gas discharge to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 It is a structural diagram of the centrifugal multiphase mixed delivery pump described in the present invention.

[0025] Figure 2 It is a front view of the impeller described in the present invention.

[0026] Figure 3 A three-dimensional diagram of the impeller according to the present invention.

[0027] Figure 4 It is a partial view of the front wall of the shell according to the present invention.

[0028] Figure 5 It is a cross-sectional view of the impeller and the front wall of the casing according to the present invention.

[0029] Figure 6 for Figure 5 A partial enlarged view of .

[0030] In the figure:

[0031] 1-housing; 2-inlet; 3-outlet; 4-pump chamber; 5-collecting chamber; 6-front chamber; 7-rear chamber; 8-housing front wall; 9-housing rear wall; 10-impeller; 11-peripheral structure; 12-guide hole; 13-rear cover; 14-blade; 15-second ridge structure; 16-first ridge structure; 17-shaft; 18-wide blade; 19-guide plate; 21-wide blade leading edge; 22-spiral groove. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The centrifugal mixed pump in the prior art comprises a housing 1 and an impeller 10, wherein the housing 1 has a pump chamber 4 for mounting the impeller 10, the pump chamber 4 having a liquid inlet 2 and an outlet 3, the impeller 10 being fixed on a shaft 17 driven by a non-motor, the pump chamber 4 being divided into a front chamber 6 and a rear chamber 7 by a rear cover plate 13 of the impeller, the front chamber 6 being a space in the pump chamber 4 near the inlet 2 (including a collecting chamber 5 extending into an annular space or a spiral form), and the rear chamber 7 being a space in the pump chamber 4 near the driving end; the rear cover plate 13 in the prior art is located near the outlet 3, such as Figure 1 In the prior art, the rear cover plate 13 separates the pump chamber 4 from the front chamber 6 and the rear chamber 7 along the plane FF, which is not conducive to the conveying of gas and liquid. In the present invention, the rear cover plate 13 is axially extended to the inside of the rear chamber 7 by a distance D, and at the same time, part of the blades 14 in the impeller 10 are axially extended to the wall of the front chamber 6, and the outer side of the hub of the impeller 10 forms a cylindrical wall 11 between the original rear cover plate position and the extended rear cover plate 13. The chamber formed by the cylindrical wall 11 and the partially axially extended blades 14 enables the conveying medium to form a circulating flow and a through flow, which is used to improve the efficiency of gas-liquid two-phase medium conveying. As can be seen from the figure, in the traditional centrifugal pump, the rear cover plate 13 is arranged so that its front surface is at least approximately located in the plane FF, and the blades 14 are completely extended in the front chamber 6 located in front of the plane FF. As for the space of the rear chamber 7, it is very limited. In the present invention, the rear cover plate 13 is axially extended to the inside of the rear chamber 7 by a distance D, which is essentially to first axially expand the space of the rear chamber 7 by a distance D, and then axially move the rear cover plate 13 by a distance D. The distance D should be between 25% and 75% of the total axial width of the blade 14, preferably about 50% of the total axial width of the blade 14. The rear surface of the rear cover plate 13 is located near the inner surface of the rear wall 9 of the housing 1.

[0036] like Figure 2 and Figure 3 As shown, some of the blades 14 distributed at intervals in the impeller 10 extend axially to form wide blades 18; in the embodiment, there are 6 blades 14 on the impeller 10, of which 3 blades 14 distributed at intervals extend axially to form wide blades 18, and one end of the wide blade 18 extends to the vicinity of the inner wall surface of the front cavity 6; one end of the wide blade 18 extending to the front cavity 6 is provided with a wide blade leading edge 21 with a folded edge, and a gap is provided between the wide blade leading edge 21 and the inner wall surface of the front cavity 6, and the gap size is 0.2-0.3mm. The axial extension distance of the wide blade 18 is 25%-75% of the axial length of the blade 14 that is not extended.

[0037] like Figure 6As shown in the figure, the angle ɑ between the front edge 21 of the wide blade and the inner wall surface of the front cavity 6 is in the range of 30° to 45°, so that a gradual gap is formed between the front edge 21 of the wide blade and the inner wall of the front cavity 6, which is beneficial to gas-liquid transportation. It is more conducive to the cooperation with the groove in the inner wall of the front cavity 6, and can cut the larger solid matter entering the pump body chamber into particles, thereby improving the efficiency of pumping solid and liquid. Figure 4 As shown, the inner wall surface of the front cavity 6 corresponding to the leading edge 21 of the wide blade is provided with a spiral groove 22 perpendicular to the axis of the impeller 10, and the cross-sectional shape of the groove 22 is an isosceles triangle, and the base length of the isosceles triangle is about one fifth of the impeller radius.

[0038] like Figure 2 and Figure 3 As shown, a guide plate 19 having a curvature close to that of the blade 14 is provided between each of the wide blades 18 and the adjacent unextended blades 14. The length of the guide plate 19 is equal to 25% to 40% of the length of the wide blade 18. In the embodiment, two guide plates 19 are provided between each of the wide blades 18 and the adjacent unextended blades 14, one guide plate 19 is located at the hub of the impeller 10, and the other guide plate 19 is located at the cylindrical wall 11. Under high-speed operation conditions, the wide blades 18 can partially restrict the axial flow of the liquid and enhance the through-flow, and the guide plates 19 can improve the circulation characteristics of the liquid flow, enhance the through-flow and the circulation flow, and reduce the generation of bubbles in the cavity.

[0039] like Figure 1 and Figure 5 As shown, the cylindrical wall 11 is in a conical shape, and the cone angle of the cylindrical wall 11 is 2γ, wherein γ does not exceed 20 degrees. In this way, the chamber formed by the cylindrical wall 11 and the partially axially extending blades 14 is also in a similar cone shape, which can make it easier for the medium entering the chamber to form a vortex.

[0040] The rear cover plate 13 is provided with a plurality of guide holes 12, and the guide holes 12 have an angle of inclination facing the edge of the impeller 10, and the value range of the inclination angle β is 25° to 45°. These holes can improve the flow characteristics of the liquid in the impeller cavity, thereby significantly improving the efficiency of gas discharge to the outside. The guide holes 12 are located between the wide blades 18 and the unextended blades 14.

[0041] like Figure 1As shown, the rear cover plate 13 has a rearward surface facing the inner surface of the rear wall 9 of the housing, and the inner surface of the rear wall 9 of the housing includes a portion facing the rearward surface of the rear cover plate, and a radially extending first ridge structure 16 is provided on the portion of the rear wall 9 of the housing. A second ridge structure 15 is provided on the rear surface of the rear cover plate 13, and the second ridge structure 15 is radially curved. The second ridge structure 15 can be radially curved or similar to the blade 14. In contrast, the first ridge structure 16 preferably extends radially and plays a role in reducing the disc friction loss on the back of the impeller, reducing the liquid pressure in the rear chamber of the pump, and ensuring that the axial force acting on the impeller is partially balanced.

[0042] The centrifugal multiphase mixed pump described in the present invention has a gas content of no more than 8% when conveying a gas-liquid mixture; a solid content of no more than 8% for a solid-liquid mixture; when conveying a three-phase mixture of gas, liquid and solid, the liquid phase is not less than 90%, and the diameter of the conveyed solid phase particles is no more than 2 / 3 of the minimum gap between blades.

[0043] The centrifugal multiphase mixed pump used in this embodiment is Figure 1 Arranged in the manner shown, the impeller rotates counterclockwise.

[0044] The centrifugal multiphase mixed pump of the present invention can be widely used in fields such as sewage treatment, petroleum engineering, chemical engineering, oxygen-containing irrigation, shipbuilding, etc., which require efficient pumping of liquids containing solid or gas mixtures.

[0045] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0046] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A centrifugal multiphase mixed flow pump, characterized in that: The invention comprises a casing (1) and an impeller (10), wherein the casing (1) has a pump chamber (4) for mounting the impeller (10), wherein the pump chamber (4) is divided into a front chamber (6) and a rear chamber (7) by a rear cover plate (13) of the impeller, wherein the front chamber (6) is a space in the pump chamber (4) close to an inlet (2), and the rear chamber (7) is a space in the pump chamber (4) close to a driving end; wherein the rear cover plate (13) extends into the interior of the rear chamber (7), and a part of the blades (14) in the impeller (10) are axially extended; a cylindrical wall surface (11) is formed on the outer side of the impeller hub between the original rear cover plate position and the extended rear cover plate (13), and the chamber formed by the cylindrical wall surface (11) and the part of the axially extended blades (14) enables the conveying medium to form a through flow and a circulating flow, so as to improve the efficiency of conveying gas-liquid two-phase medium.

2. The centrifugal multiphase mixed flow pump according to claim 1, characterized in that: Some of the blades (14) distributed at intervals in the impeller (10) extend axially to form wide blades (18), one end of the wide blade (18) extends to the vicinity of the inner wall surface of the front cavity (6); one end of the wide blade (18) extending to the front cavity (6) is provided with a wide blade leading edge (21) with a folded edge, and a gap is provided between the wide blade leading edge (21) and the inner wall surface of the front cavity (6).

3. The centrifugal multiphase mixed flow pump according to claim 2, characterized in that: The axial extension distance of the wide blade (18) is 25% to 75% of the axial length of the unextended blade (14).

4. The centrifugal multiphase mixed flow pump according to claim 2, characterized in that: The value range of the angle ɑ between the leading edge (21) of the wide blade and the inner wall surface of the front cavity (6) is 30° to 45°.

5. The centrifugal multiphase mixed flow pump according to claim 1, characterized in that: A guide plate (19) having a curvature close to that of the blade (14) is provided between each wide blade (18) and its adjacent unextended blade (14).

6. The centrifugal multiphase mixed flow pump according to claim 5, characterized in that: The length of the guide plate (19) is equal to 25% to 40% of the length of the wide blade (18).

7. The centrifugal multiphase mixed flow pump according to claim 5, characterized in that: Two guide plates (19) are arranged between each wide blade (18) and its adjacent unextended blade (14), one guide plate (19) being located at the hub of the impeller (10) and the other guide plate (19) being located at the cylindrical wall (11).

8. The centrifugal multiphase mixed flow pump according to claim 1, characterized in that: The cylindrical wall surface (11) is in a conical shape, and the cone angle of the cylindrical wall surface (11) is 2γ, wherein γ does not exceed 20 degrees.

9. The centrifugal multiphase mixed flow pump according to claim 2, characterized in that: The inner wall surface of the front cavity (6) corresponding to the leading edge (21) of the wide blade is provided with a spiral groove (22) perpendicular to the axis of the impeller (10), and the cross-sectional shape of the groove (22) is an isosceles triangle.

10. The centrifugal multiphase mixed flow pump according to claim 1, characterized in that: The rear cover plate (13) is provided with a plurality of guide holes (12), the guide holes (12) having a slope angle facing the edge of the impeller (10), and the slope angle β has a value range of 25° to 45°.

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