A double-suction fully symmetrical multistage pump

Abstract

The present invention discloses a double-suction fully symmetrical multistage pump, comprising a secondary impeller, a double-suction impeller and a double-suction pump body. The double-suction pump body is arranged outside the double-suction impeller, and the double-suction impeller is a completely symmetrical structure. The double-suction pump body is located on the coaxial line of the double-suction impeller, thereby providing a double-suction fully symmetrical multistage pump, thereby realizing a multi-stage double-suction pump is conveniently formed on the premise of making maximum use of existing single-suction multistage pump parts, thereby multiplying the flow rate of the pump and expanding the performance range of the pump; since the first-stage impeller, the secondary impeller and the double-suction impeller are completely symmetrically arranged, the axial force is completely balanced, and the theoretical axial force is zero; the flow area of ​​the first-stage impeller is larger than that of the secondary impeller, thereby improving the cavitation performance of the pump; the use of the double-suction impeller and the double-suction pump body is convenient for liquid collection and convergence, thereby improving the hydraulic efficiency of the pump; the double-axle extension scheme is adopted, and it can be driven from either end, thereby meeting the diverse requirements of pump installation.

Description

Technical Field

[0001] The invention belongs to the technical field related to multi-stage double-suction pumps, and in particular relates to a double-suction fully symmetrical multi-stage pump. Background Art

[0002] A multistage pump is a pump that connects the impellers of a single-stage pump concentrically through an axis to increase the pump head or pressure while keeping the flow rate constant. A pump with two impellers is called a two-stage pump, and a pump with multiple impellers is called a multistage pump. The medium is first sucked in from the first-stage impeller, and after being pressurized by the first-stage impeller, it enters the suction port of the second-stage impeller through the flow channel or guide vane, and is pressurized by the second-stage impeller. After being pressurized by multiple impellers, the medium is collected by the vortex chamber at the outlet section and flows out through the outlet flange. This is essentially a single-suction multistage pump.

[0003] Due to its working principle, the single-suction multi-stage pump will generate a large axial force. The bearing will be severely worn due to the increased load and temperature, which greatly shortens the bearing life. At the same time, the single-suction multi-stage pump cannot easily expand the pump flow to twice the design flow. Finally, the cavitation performance of the single-suction multi-stage pump cannot be effectively guaranteed.

[0004] At present, the existing technology cannot solve the above problems at the same time. In order to deal with the problem of axial force, the existing technology uses a balancing disc or a balancing drum, which makes the pump structure complicated, the performance of the pump cannot be expanded, and the reliability is also reduced; at the same time, if the axial force is simply balanced in parallel, the cavitation problem cannot be solved, and the efficiency will also be reduced due to the impact of the liquid flow. Summary of the invention

[0005] The object of the present invention is to provide a double-suction fully symmetrical multi-stage pump to solve the problems of axial force balance, performance expansion, low efficiency and cavitation performance raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A double-suction fully symmetrical multistage pump comprises a secondary impeller, a double-suction impeller, a double-suction pump body and a pump shaft, characterized in that: the pump shaft has a completely symmetrical structure, wherein a double-suction impeller is arranged on a vertical plane, the double-suction pump body is sleeved on the outside of the double-suction impeller, and the double-suction impeller coincides with the middle vertical plane of the double-suction pump body, and a pair of last-stage radial guides, a secondary impeller, a middle section, a radial guide, a first-stage impeller and a suction section are symmetrically arranged on both sides of the double-suction impeller in sequence, the secondary impeller (3) is placed in the inner cavity of the radial guide or the last-stage radial guide, the first-stage impeller is placed in the inner cavity of the radial guide or the last-stage radial guide, and the U-shaped suction pipe is connected to the left and right suction sections through flanges.

[0008] Preferably, the double-suction fully symmetrical multi-stage pump has a completely symmetrical structure, and its symmetry plane is the median vertical plane of the double-suction impeller. The double-suction fully symmetrical multi-stage pump includes a pair of suction sections, a pair of first-stage impellers, n pairs of secondary impellers, n pairs of radial guides, n pairs of middle sections, a pair of final-stage radial guides, a double-suction impeller, a double-suction pump body, and a pump shaft (where n is an integer, n=0, 1, 2, 3, 4, 5..., the size of n depends on the pump head).

[0009] Preferably, the double-suction fully symmetrical multi-stage pump has a double shaft extension and can be driven from either end according to actual needs; the pump shaft is a symmetrical structure, and its length corresponds to the value of n.

[0010] Preferably, the U-shaped suction pipe has an inlet flange, two outlet flanges and a U-shaped branch pipeline, and the flow channel area of ​​the inlet flange is twice the flow channel area of ​​the outlet flange.

[0011] Preferably, the double-suction pump body has a spiral water pressure chamber for collecting, converging and equalizing the pressure of fluids.

[0012] Preferably, the main casing of the double-suction fully symmetrical multi-stage pump is substantially cylindrical in shape (excluding the flange).

[0013] Preferably, the last-stage radial guide vane includes a front cover plate, a middle cover plate, a rear cover plate, a positive guide vane and a reverse guide vane, the positive guide vane is between the front cover plate and the middle cover plate, the reverse guide vane is between the middle cover plate and the rear cover plate, and the number of blades of the positive guide vane is equal to the number of blades of the reverse guide vane.

[0014] Preferably, the inlet diameter of the first-stage impeller is 1.05 to 1.2 times the inlet diameter of the secondary impeller and the double-suction impeller, the inlet placement angle of the blades of the first-stage impeller is 13° to 18°, and the number of blades of the first-stage impeller is 1 or 2 less than the number of blades of the secondary impeller and the double-suction impeller.

[0015] Preferably, the pull rod connects and tightens the suction sections at the left and right ends, and multiple pull rods make the present invention a whole.

[0016] Compared with the prior art, the present invention provides a double-suction fully symmetrical multi-stage pump, which has the following beneficial effects:

[0017] A double-suction fully symmetrical multistage pump is provided, so that a multistage double-suction pump can be conveniently formed on the premise of making maximum use of the parts of the existing single-suction multistage pump, thereby doubling the flow rate of the pump and expanding the performance range of the pump; since the first-stage impeller, the secondary impeller and the double-suction impeller are arranged completely symmetrically, the axial force is completely balanced and the theoretical axial force is zero; the flow area of ​​the first-stage impeller is larger than that of the secondary impeller, thereby improving the cavitation performance of the pump; the use of the double-suction impeller and the double-suction pump body facilitates liquid collection and convergence, thereby improving the hydraulic efficiency of the pump; the double-axle extension scheme is adopted, and the pump can be driven from either end, thereby meeting the diverse requirements of pump installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 A schematic diagram of the structure of a double-suction fully symmetrical multi-stage pump proposed by the present invention;

[0020] Figure 2 A schematic diagram of the external structure proposed by the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the final-stage radial guide device proposed in the present invention;

[0022] In the figure: 1. Suction section; 2. First-stage impeller; 3. Secondary impeller; 4. Radial guide vane; 5. Last-stage radial guide vane; 51. Front cover plate; 52. Middle cover plate; 53. Rear cover plate; 54. Positive guide vane; 55. Reverse guide vane; 6. Double-suction impeller; 7. Double-suction pump body; 8. Middle section; 9. Pump shaft; 10. U-shaped suction pipe; 11. Pull rod. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms "left", "right", "inside", "outside", "two ends", "one end", "the other end" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" 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 indirectly connected 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.

[0026] See also Figure 1-3 , the present invention provides a technical solution:

[0027] A double-suction fully symmetrical multistage pump comprises a secondary impeller 3, a double-suction impeller 6, a double-suction pump body 7 and a pump shaft 10, characterized in that: the pump shaft 10 has a completely symmetrical structure, wherein the double-suction impeller 6 is arranged on a vertical plane, the double-suction pump body 7 is sleeved on the outside of the double-suction impeller 6, and the double-suction impeller 6 coincides with the middle vertical plane of the double-suction pump body 7, and the two sides of the double-suction impeller 6 are symmetrically arranged with a pair of final-stage radial guides 5, a secondary impeller 3, a middle section 8, a radial guide 4, a first-stage impeller 2 and a suction section 1 in sequence, the secondary impeller 3 is placed in the inner cavity of the radial guide 4 or the final-stage radial guide 5, the first-stage impeller 2 is placed in the inner cavity of the radial guide 4 or the final-stage radial guide 5, and the U-shaped suction pipe 10 is connected to the left and right two suction sections 1 through flanges.

[0028] A double-suction fully symmetrical multistage pump has a completely symmetrical structure, and its symmetry plane is the mid-vertical plane of a double-suction impeller 6. The double-suction fully symmetrical multistage pump comprises a pair of suction sections 1, a pair of first-stage impellers 2, n pairs of secondary impellers 3, n pairs of radial guides 4, n pairs of middle sections 8, a pair of final-stage radial guides 5, a double-suction impeller 6, a double-suction pump body 7, and a pump shaft 9 (where n is an integer, n=0, 1, 2, 3, 4, 5..., and the size of n depends on the pump head). The double-suction fully symmetrical multistage pump has a double shaft extension and can be driven from any section according to actual needs; the pump shaft 9 is a symmetrical structure, and its length corresponds to the value of n; the U-shaped suction pipe 10 has an inlet flange and two outlet flanges and a U-shaped branch pipeline, and the inlet flange flow channel area is twice the outlet flange flow channel area; the double-suction pump body 7 has a spiral pressure The water chamber is used for collecting, converging and balancing the fluid; the main body shell of the double-suction fully symmetrical multi-stage pump is basically a cylindrical shape except for the flange. The final radial guide 5 includes a front cover plate 51, a middle cover plate 52, a rear cover plate 53, a positive guide vane 54 and a reverse guide vane 55. The positive guide vane 54 is between the front cover plate 51 and the middle cover plate 52, and the reverse guide vane 55 is between the middle cover plate 52 and the rear cover plate 53. The number of blades of the positive guide vane 54 is the same as that of the reverse guide vane 55. The number of blades of the reverse guide vane 55 is equal; the inlet diameter of the first-stage impeller 2 is 1.05 to 1.2 times the diameter of the secondary impeller 3 and the double-suction impeller 6, the inlet placement angle of the blades of the first-stage impeller 2 is 13° to 18°, and the number of blades of the first-stage impeller 2 is 1 or 2 less than the number of blades of the secondary impeller 3 and the double-suction impeller 6; the pull rod 11 connects and tightens the suction sections 1 at the left and right ends, and multiple pull rods 11 make the present invention form a whole.

[0029] The working principle and use process of the present invention are as follows: After the present invention is installed, the liquid is sucked in from the inlet flange of the U-shaped suction pipe 10, and then is divided into two paths along the U-shaped branch pipeline, flowing out from the left and right outlet flanges respectively, and entering the left and right suction sections 1, and then symmetrically enters from the left and right at one time and flows through the first-stage impeller 2, the radial guide device 4, the secondary impeller 3, and the final-stage radial guide device 5. Finally, the two paths of liquid converge in the double-suction impeller 6, and after being collected and pressure-stabilized by the spiral water pressure chamber of the double-suction pump body 7, they flow out from the flange port of the double-suction pump body 7.

[0030] The inlet diameter of the first-stage impeller 2 is 1.05 to 1.2 times the diameter of the secondary impeller 3 and the double-suction impeller 6. The inlet placement angle of the blades of the first-stage impeller 2 is 13° to 18°. When the liquid flows through the first-stage impeller 2, the flow area of ​​the first-stage impeller 2 is larger than that of the secondary impeller 3, and the number of blades of the first-stage impeller 2 is small, which reduces the displacement of the liquid and reduces the flow rate. At the same time, due to the small inlet angle of the blades, the impact of the liquid is reduced, so the cavitation performance of the pump is significantly improved; because the liquid enters the multi-stage pump in two ways, it is very convenient to form a multi-stage double-suction pump on the premise of maximizing the use of the parts of the existing single-suction multi-stage pump, which doubles the flow rate of the pump and expands the performance range of the pump. Since the first-stage impeller 2, the secondary impeller 3, and the double-suction impeller 6 are arranged completely symmetrically, the axial force is completely balanced, and the theoretical axial force is zero; due to the use of a double-axle extension scheme, it can be driven from either end, meeting the diverse requirements of pump installation.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A double-suction fully symmetrical multistage pump, comprising a secondary impeller (3), a double-suction impeller (6), a double-suction pump body (7), a pump shaft (9) and a U-shaped suction pipe (10), characterized in that: The pump shaft (9) has a completely symmetrical structure, wherein a double-suction impeller (6) is arranged on a vertical plane, the double-suction pump body (7) is sleeved on the outside of the double-suction impeller (6), and the mid-vertical plane of the double-suction impeller (6) coincides with that of the double-suction pump body (7), and a pair of final-stage radial guides (5), a secondary impeller (3), a middle section (8), a radial guide (4), a first-stage impeller (2) and a suction section (1) are symmetrically arranged on both sides of the double-suction impeller (6) in sequence, the secondary impeller (3) is placed in the inner cavity of the radial guide (4) or the final-stage radial guide (5), the first-stage impeller (2) is placed in the inner cavity of the radial guide (4) or the final-stage radial guide (5), and the left and right suction sections (1) are connected to a U-shaped suction pipe (10) via flanges; The U-shaped suction pipe (10) has an inlet flange, two outlet flanges and a U-shaped branch pipeline, and the flow channel area of ​​the inlet flange is twice the flow channel area of ​​the outlet flange; the double-suction pump body (7) has a spiral water pressure chamber for collecting, converging and equalizing the pressure of the fluid; The final-stage radial guide vane (5) comprises a front cover plate (51), a middle cover plate (52), a rear cover plate (53), a positive guide vane (54) and a reverse guide vane (55), wherein the positive guide vane (54) is disposed between the front cover plate (51) and the middle cover plate (52), and the reverse guide vane (55) is disposed between the middle cover plate (52) and the rear cover plate (53), and the number of blades of the positive guide vane (54) is equal to the number of blades of the reverse guide vane (55); The inlet diameter of the first-stage impeller (2) is 1.05 to 1.2 times the inlet diameter of the secondary impeller (3) and the double-suction impeller (6); the inlet placement angle of the blades of the first-stage impeller (2) is 13° to 18°; the number of blades of the first-stage impeller (2) is one or two less than the number of blades of the secondary impeller (3) and the double-suction impeller (6).

2. A double-suction fully symmetrical multistage pump according to claim 1, characterized in that: The double-suction fully symmetrical multi-stage pump has a completely symmetrical structure, and its symmetry plane is the median vertical plane of the double-suction impeller (6). The double-suction fully symmetrical multi-stage pump comprises a pair of suction sections (1), a pair of first-stage impellers (2), n pairs of secondary impellers (3), n pairs of radial flow guides (4), n pairs of middle sections (8), a pair of final-stage radial flow guides (5), a double-suction impeller (6), a double-suction pump body (7), and a pump shaft (9).

3. A double-suction fully symmetrical multistage pump according to claim 2, characterized in that: The double-suction fully symmetrical multi-stage pump has double shaft extensions and can be driven from either end according to actual needs; the pump shaft (9) is a symmetrical structure, and its length corresponds to the value of n.

4. A double-suction fully symmetrical multistage pump according to claim 1, characterized in that: The main body shell of the double-suction fully symmetrical multi-stage pump is basically cylindrical in shape.

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