CN108700078B - Diffuser and multistage pump device - Google Patents

Diffuser and multistage pump device Download PDF

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Publication number
CN108700078B
CN108700078B CN201780014161.8A CN201780014161A CN108700078B CN 108700078 B CN108700078 B CN 108700078B CN 201780014161 A CN201780014161 A CN 201780014161A CN 108700078 B CN108700078 B CN 108700078B
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diffuser
flow path
impeller
angle
fluid
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CN108700078A (en
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平本和也
大渊真志
前田毅
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Ebara Corp
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Ebara Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D1/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D1/06—Multi-stage pumps
    • F04D1/08—Multi-stage pumps the stages being situated concentrically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/445—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps
    • F04D29/448—Fluid-guiding means, e.g. diffusers especially adapted for liquid pumps bladed diffusers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D1/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D1/06—Multi-stage pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D11/00—Other rotary non-positive-displacement pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

The invention relates to a diffuser and a multistage pump device, wherein the diffuser (250) comprises: a housing section (260, 270) that divides a cylindrical flow path so as to have a diameter that decreases from the fluid inlet side to the fluid outlet side; and a plurality of diffuser blades (280) which are arranged in the cylindrical flow path and divide the cylindrical flow path into a spiral shape. In any meridian plane position of the casing (260, 270), an angle formed between the circumferential direction with respect to the rotation axis and the airfoil tangential direction of the diffuser wing section is defined as a diffuser wing angle β w for the plurality of diffuser wing sections (280). The diffuser blade angle β w (°) changes at a change amount Δ β w satisfying a relationship of Δ β w < 2.4 · Δ Xc with respect to a unit change amount Δ Xc (mm) of the meridian position. In addition, the diffuser vane angle β w is less than 90 ° in all regions.

Description

Diffuser and multistage pump device
Technical Field
The invention relates to a diffuser and a multistage pump device.
Background
Conventionally, a multistage pump is widely used for transporting a fluid. The multistage pump is configured by housing a multistage impeller arranged along a drive shaft in a diffuser that divides a flow path of a fluid. The diffuser rectifies the fluid pressurized by the impeller in a spiral guide and conveys the fluid to the lower-stage impeller. In a multistage pump, a desired head can be obtained by changing the number of stages of the impeller and the diffuser.
Patent document 1 Japanese patent application laid-open No. 6-323291
In a multistage pump device, the shape of a diffuser is designed so that the energy conversion efficiency is maximized when the multistage pump device is operated at a predetermined rated discharge amount. For example, in general, the diffuser has an angle β w of the diffuser vanes that divide the internal flow path: the rotational speed component of the outlet fluid is removed and directed in the axial direction. However, in order to suppress the separation of the fluid in the diffuser and remove the rotational speed component of the outlet fluid, the axial length of the diffuser needs to be increased, which leads to a problem that the overall length of the pump is increased.
In order to eliminate the rotational speed component of the outlet fluid in a diffuser having a short axial length, the diffuser blade angle β w needs to be increased, and the increase in the blade angle β w from the inlet to the outlet is also increased. In this case, the fluid in the diffuser is likely to be peeled off, and the efficiency of the diffuser is reduced due to the secondary flow (turbulent flow of the fluid) in the diffuser. In addition, when the impeller and the diffuser are stacked in multiple stages, the separation occurring in the upper stage diffuser affects the lower stage impeller and the lower stage diffuser, thereby reducing the energy efficiency.
Disclosure of Invention
The present invention has been made in view of the above problems, and an object of the present invention is to provide a diffuser and a multistage pump device that are small and have high energy conversion efficiency, in a multistage pump device that is a multistage stacked diffuser.
The diffuser of the present invention is used in a multistage pump, and is disposed concentrically with an impeller that rotates about a rotation axis, and guides a fluid that is induced by the rotation of the impeller. The diffuser includes: a housing section that divides a cylindrical flow path so that the diameter thereof becomes smaller from an inflow side toward an outflow side of a fluid; and a plurality of diffuser blades arranged in the cylindrical flow path to divide the cylindrical flow path into a spiral shape. In the plurality of diffuser wing portions, an angle formed between the circumferential direction of the casing portion with respect to the rotation axis and the tangential direction of the airfoil surface of the diffuser wing portion at an arbitrary meridian plane position is defined as a diffuser wing angle β w. The unit change amount Δ Xc (mm) of the diffuser vane angle β w (°) with respect to the meridian position changes by an amount of change Δ β w that satisfies the relationship Δ β w < 2.4 · Δ Xc. In addition, the diffuser vane angle β w is less than 90 ° in all regions. Accordingly, the rotation speed component remains in the outlet fluid of the diffuser, and the outlet fluid of each diffuser can be stabilized regardless of the pump flow rate, thereby realizing a small-sized multi-stage pump device having high energy conversion efficiency.
Preferably, the maximum outer diameter Φ Dc of the flow path defined by the casing portion and the meridian vane length Lc on the outer peripheral side of the diffuser vane portion satisfy Lc/Φ Dc < 0.64.
Preferably, the maximum inner diameter Φ Dh of the flow path defined by the casing portion and the meridian vane length Lh on the inner circumferential side of the diffuser vane portion satisfy a relationship of Lh/Φ Dh < 0.63.
Preferably, the meridian plane wing length Lh on the inner peripheral side of the diffuser wing portion is equal to or less than the meridian plane wing length Lc on the outer peripheral side.
Preferably, the wall surface on the inner circumferential side of the outflow-side end of the case portion is located downstream of a position where the inner diameter of the flow path is largest, and a maximum value θ o of an angle formed with the rotation axis satisfies θ o > 1500 · Ns with respect to the specific speed Ns-0.6The relationship (2) of (c). Here, the rotational speed (min) of the pump is set-1) Np is the discharge amount (m)3Min) is Qp, and the total head (m) is Hp, the specific speed Ns is (Np · Qp) with Ns1/2)/Hp3/4And (4) showing.
The multistage pump device of the present invention includes: a plurality of stages of the above-described diffuser of the present invention; and a plurality of stages of impellers concentrically arranged with the diffuser and inducing the fluid toward the diffuser.
According to the multistage pump device, the same effects as those of the diffuser of the present invention can be obtained.
The multistage pump device may further include a power source for rotating the impeller.
Drawings
Fig. 1 is a longitudinal sectional view schematically showing a multistage pump device of the present embodiment.
Fig. 2 is a schematic view showing an enlarged periphery of the diffuser according to the present embodiment.
Fig. 3 is a schematic view of the inner casing portion of the diffuser and the diffuser wings, with the outer casing portion omitted.
Fig. 4 is a graph showing an efficiency curve of the impeller with respect to the discharge amount of the multistage pump.
Fig. 5 is a graph showing an efficiency curve of the diffuser with respect to the discharge amount of the multistage pump.
Detailed Description
Hereinafter, a diffuser and a multistage pump device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, a deep well submersible motor pump provided with a submersible pump is described as an example, and the present invention is not limited to such an example, and can be applied to various multistage pump devices and diffusers.
Fig. 1 is a longitudinal sectional view schematically showing a multistage pump of the present embodiment. In the figure, thick line arrows schematically show the flow of fluid. As shown in fig. 1, the multistage pump device 10 includes: a motor 100 as a power source, and a pump unit 200 attached to an upper portion of the motor 100.
The motor 100 is connected to an external power supply not shown via a cable 102. The drive shaft 104 of the motor 100 is connected to the main shaft 230 of the pump section 200 via the joint 106. In the present embodiment, the drive shaft 104 of the motor 100 and the main shaft 230 of the pump unit 200 are concentrically arranged extending in the direction of the axis (rotation axis) Aw. The motor 100 may be any motor as long as it can rotate the main shaft 230 of the pump section 200. The motor 100 is not the core of the present invention, and thus, a detailed description thereof will be omitted.
The pump section 200 includes: a suction casing 210, a discharge casing 220, a main shaft 230, an impeller 240, and a diffuser 250.
The suction casing 210 is provided above the motor 100 and is disposed as the lowest stage of the pump section 200. The suction casing 210 is fixed to the motor 100 by fastening the lower assembly portion 212 to the casing 108 of the motor 100 with screws 214. The suction casing 210 is formed in a substantially cylindrical shape, and a suction port 216 for sucking fluid is formed in an upper portion of the assembly portion 212. The diffuser 250 is fixed to the assembly portion 218 of the upper portion of the suction casing 210 by fastening the assembly portion 252 of the diffuser 250 with screws 253.
The discharge casing 220 is provided above the diffuser 250 and is disposed as the uppermost stage of the pump section 200. The discharge casing 220 is fixed to the diffuser 250 by fastening the lower assembly portion 222 and the assembly portion 254 of the diffuser 250 with screws 255. The discharge housing 220 is formed in a substantially cylindrical shape, and an upper assembly portion 224 is attached to a discharge pipe, not shown. The discharge casing 220 includes a check valve 226 therein to suppress backflow of the fluid.
The main shaft 230 is connected to the motor 100 via the joint 106 and is inserted into the suction housing 210 and the diffuser 250. The main shaft 230 is shaft supported by a bearing sleeve 268 of the diffuser 250. A plurality of impellers 240 are attached to the main shaft 230, and the plurality of impellers 240 rotate with the rotation of the main shaft 230.
The impeller 240 has: a cylindrical insertion portion for inserting the main shaft 230, and a plurality of blades attached to an outer circumferential surface of the insertion portion. The impeller 240 rotates integrally with the main shaft 230, and the fluid is pumped from upstream (lower side in the figure) to downstream (upper side in the figure) by the plurality of blades.
The diffuser 250 is made of metal, resin, or the like, and is disposed concentrically with the rotation shaft (the main shaft 230) of the impeller 240. Fig. 2 is a schematic view showing the periphery of the diffuser of the present embodiment in an enlarged manner. In addition, fig. 2 shows a cross section along the axis Aw, but for the diffuser wings 280, one diffuser wing 280 is shown along the airfoil. In addition, the diffuser wings 280 are not cross-sectioned but are marked with grid lines for easy understanding. Hereinafter, a cross section along the axis Aw will be referred to as a "meridian plane".
In this embodiment, the diffuser 250 houses the main shaft 230 and the impeller 240 and divides a flow path of the fluid. The diffuser 250 includes a liner ring 258 between itself and the impeller 240 to prevent a reverse flow of the fluid. The diffuser 250 has assembling portions 252 and 254 in the vertical direction, and can fix the suction casing 210 and the discharge casing 220. The diffuser 250 can be formed by stacking a plurality of stages with the set of the diffuser 250 and the impeller 240 as one stage (in the example of fig. 1, two stages are stacked).
Fig. 3 is a schematic view of the inner casing portion of the diffuser and the diffuser wings, with the outer casing portion omitted. Also in fig. 3, as corresponding to fig. 2, grid lines are marked on the airfoil of one diffuser airfoil 280. As shown in fig. 2 and 3, the diffuser 250 includes: an inner housing 260 defining an inner wall of the flow path, an outer housing 270 defining an outer wall of the flow path, and a plurality of diffuser vanes 280 connecting the inner housing 260 and the outer housing 270. The inner housing portion 260, the outer housing portion 270, and the diffuser wing portion 280 may be integrally formed by, for example, casting metal, or may be formed separately and connected to each other.
The inner housing portion 260 is provided with a bearing sleeve 268 (see fig. 1) into which the main shaft 230 is inserted. As shown in fig. 1 to 3, the inner housing portion 260 is formed in a substantially cylindrical shape having a diameter that decreases toward the upper side (downstream). The outer case portion 270 has a space therein having a shape corresponding to the outer contour of the inner case portion 260 so as to define a flow path between the outer case portion and the inner case portion 260. That is, the outer case portion 270 is formed in a hollow shape and in a substantially cylindrical shape having a diameter that decreases as the diameter increases upward. The inner housing portion 260 and the outer housing portion 270 are disposed apart from each other, thereby defining a cylindrical flow path Fc through which the fluid induced from the impeller 240 passes.
The inner casing portion 260 and the outer casing portion 270 are connected by a plurality of (seven in the present embodiment) diffuser vanes 280 in a state of being separated from each other. The plurality of diffuser wing portions 280 are arranged in the cylindrical flow path Fc in a uniform positional relationship in the circumferential direction with respect to the axis Aw, and are each formed in a plate shape having a smooth curved plate surface (airfoil surface).
As shown in fig. 2 and 3, the diffuser blades 280 are circumferentially arranged so as to divide the cylindrical flow path Fc defined by the inner and outer casing portions 260 and 270 by the airfoil surfaces. The diffuser wings 280 are provided as: at the lower end (the end on the inflow side of the flow path), the plate surface is substantially perpendicular to the axial direction of the spindle 230, and at the upper end (the end on the outflow side of the flow path), the plate surface is substantially parallel to the axial direction of the spindle 230. The diffuser blades 280 thus divide the space defined by the inner and outer casing portions 260 and 270 into a plurality of spiral flow paths.
In the present embodiment, the diffuser wing 280 is configured to: the flap angle β w changes by a small change amount Δ β w. Here, the blade angle β w is an angle (°) formed by a tangent line to the blade thickness center line Cd of the diffuser blade 280 along the flow path of the fluid and a circumferential tangent line Rd around the axis Aw with respect to the tangent line. In the present embodiment, the thickness of the diffuser wing 280 is substantially constant, and the tangent to the center line Cd of the wing thickness is substantially the same as the tangent to the airfoil. However, the blade angle β w may be an angle (°) formed by a tangent line to the blade surface on the upstream side (lower side in the drawing) or the downstream side (upper side in the drawing) of the diffuser blade 280 and a circumferential tangent line Rd around the axis Aw, instead of the center line Cd of the blade thickness. The flap angle β w changes depending on the position Xc (mm) of the meridian plane of the inner housing 260 and the outer housing 270 (see the flap angle β w (Xc1) with respect to the position Xc1 and the flap angle β w (Xc2) with respect to the position Xc2 in the figure). Specifically, the blade angle β w becomes smaller near the inlet (lower in the drawing) of the diffuser 250 and becomes larger near the outlet (upper in the drawing). This can rectify the fluid, which is induced from the impeller 240 and contains a large amount of flow components in the circumferential direction, and guide the fluid downstream (upward in the drawing). In the diffuser wing portion 280 of the present embodiment, the amount of change Δ β w in the wing angle β w with respect to the unit amount of change Δ Xc in the position Xc of the meridian plane satisfies the relationship shown in the following expression (1) in all regions. In other words, for the wing angle β w, the derivative differentiated at the meridian plane position Xc is a value less than 2.4(°/mm) in all regions. In addition, the diffuser wing angle β w is formed to be less than 90 ° in all regions. Thereby, a rotational speed component is intentionally left in the fluid discharged from the outlet of the diffuser 250. By designing the diffuser wing portions 280 by specifying the wing angle β w in this manner, even if the length of the meridian plane is reduced, the occurrence of separation of the fluid in the diffuser 250 can be suppressed. In addition, the flow of the fluid induced by the diffuser 250 after the second stage can be stabilized. This can improve the energy conversion efficiency particularly in the diffuser 250 after the second stage, and can improve the energy conversion efficiency of the multistage pump device 10.
Δβw＜2.4·ΔXc…(1)
Generally, the diffuser 250 is designed in such a manner that the flow component of the fluid discharged from the outlet side includes as little rotational speed component as possible. Therefore, the conventional diffuser 250 has a portion where the blade angle β w of the diffuser wing portion 280 is larger than 90 °, and the blade angle β w changes by a large change amount Δ β w. However, it can be seen that: if the wing angle β w has a portion larger than 90 ° or changes by a large change amount Δ β w, the fluid in the diffuser 250 is likely to be peeled off, and the energy efficiency is reduced particularly in the diffuser 250 after the second stage. Therefore, in the present embodiment, the relationship of equation (1) is satisfied in all regions, and the diffuser vane angle β w is set to an angle smaller than 90 °, and is designed to intentionally leave a rotational speed component in the fluid discharged from the outlet of the diffuser 250. This can suppress the occurrence of separation of the fluid in the diffuser 250, stabilize the flow of the fluid induced by the second and subsequent stages of the diffuser 250, and improve the energy conversion efficiency of the multistage pump device 10.
In the diffuser 250, the maximum outer diameter Φ Dc of the flow path Fc defined by the outer casing portion 270 and the meridian plane length Lc on the outer peripheral side of the diffuser wing portion 280 satisfy the relationship of the following expression (2). In the diffuser 250, the maximum inner diameter Φ Dh of the flow path Fc defined by the inner casing 260 and the meridian plane fin length Lh on the inner circumferential side of the diffuser fin 280 satisfy the relationship of the following expression (3). Here, the meridional blade lengths Lc and Lh on the outer and inner peripheral sides of the diffuser blades 280 are lengths of regions where the diffuser blades 280 are provided on the meridional surfaces of the outer casing portion 270 and the inner casing portion 260 (see fig. 2). The meridian plane blade lengths Lc and Lh are such that the meridian plane blade length Lh on the inner peripheral side is equal to or less than the meridian plane blade length Lc on the outer peripheral side (satisfy the following equation (4)). By satisfying such a relationship, the diffuser 250 having a short length in the direction of the axis Aw can be obtained, and by expressing the relationship of equation (1), the multistage pump device 10 having a small size and high energy conversion efficiency can be realized.
Lc/φDc＜0.64…(2)
Lh/φDh＜0.63…(3)
Lh≤Lc…(4)
In addition, forThe maximum value θ o of the angle formed by the axis line Aw at the outer peripheral surface of the meridian cross section of the inner housing portion 260 in the portion located on the discharge side of the position where the inner diameter of the flow path Fc is at the maximum (═ Φ Dh) satisfies the relationship of the following expression (5) with respect to the specific speed Ns. Here, the rotation speed (min-1) Np is the discharge amount (m)3Min) is Qp and the total head (m) is Hp, the specific speed Ns is represented by the following formula (6). By satisfying such a relationship, the diffuser 250 having a small length in the direction of the axis Aw can be obtained, and by expressing the relationship of equation (1), the multistage pump device 10 having a small size and high energy conversion efficiency can be realized. In the present embodiment, the outer peripheral surface of the inner housing portion 260 has the largest angle (θ o) with the axis Aw at the outflow-side end portion (the upper end portion in the drawing) (see fig. 2). However, the present invention is not limited to this example, and the outer peripheral surface of the inner housing portion 260 may have the largest angle with the axis Aw at a position other than the outflow-side end portion.
θo＞150O·Ns-0.6…(5)
Ns＝(Np.Qp1/2)/Hp3/4…(6)
Fig. 4 is a graph showing an efficiency curve of the impeller with respect to the discharge amount of the multistage pump, and fig. 5 is a graph showing an efficiency curve of the diffuser with respect to the discharge amount of the multistage pump. Here, the thick solid lines in fig. 4 and 5 are graphs showing the first-stage impeller 240 and the diffuser 250 for the multistage pump device 10 of the present embodiment that all satisfy the relationships of the above equations (1) to (5). The thick dashed line in the drawing is a graph showing the second-stage impeller 240 and the diffuser 250 for the multistage pump device 10 of the present embodiment. The thin solid lines in the figure are graphs showing the first-stage impeller and the diffuser for the multi-stage pump device of the comparative example that does not satisfy the relationships of the above equations (1) to (5). The thin dashed lines in the drawing are diagrams showing the second-stage impeller and the diffuser for the multi-stage pump device of the comparative example. As shown in fig. 4 and 5, the multistage pump device 10 is designed such that the angle of the diffuser vane 280 is designed to maximize efficiency with a specific discharge amount as the rated Md. Further, if the discharge amount is far from the rated Md, the flow of the fluid does not match the angle of the diffuser vanes 280, and the energy efficiency is lowered.
In general, the diffuser 250 is designed to have the highest efficiency for the energy conversion efficiency of objects in which the same object is stacked in multiple stages and the diffuser 250 is one stage. However, in this case, as shown in the comparative example of fig. 4 and 5, while high energy conversion efficiency can be achieved for the first-stage impeller and the diffuser (see the thin solid line in the figure), energy efficiency is reduced for the second-stage impeller and the diffuser (see the thin broken line in the figure). This is due to: the flow of fluid through the first stage impeller and diffuser includes turbulence that affects the second and subsequent stages of the impeller and diffuser. In particular, when the discharge amount of the pump is large, the fluid in the diffuser is separated, and the energy conversion efficiency of the impeller and the diffuser is significantly reduced. Further, as the meridian plane of the diffuser is shorter, that is, as the length of the diffuser in the axial line Aw direction is shorter, the fluid in the diffuser is more likely to generate turbulence, and the energy efficiency of the impeller and the diffuser in the second stage and thereafter is reduced.
On the other hand, in the multistage pump device 10 of the present embodiment, the diffuser 250 is designed so as to satisfy the relationships of the above equations (1) to (5). As a result, as shown by the thick solid lines and the broken lines in fig. 4 and 5, in the diffuser 250 having a small length in the direction of the axis Aw, the energy conversion efficiency of the second-stage impeller 240 and the diffuser 250 can be improved. This is based on intentionally leaving a rotational velocity component in the fluid discharged from the outlet of the diffuser 250. This stabilizes the flow of the fluid induced by the second and subsequent stages of the impeller 240 and the diffuser 250, and improves the energy conversion efficiency as compared with the multi-stage pump device of the comparative example. In addition, even when the number of stages of the diffuser 250 and the impeller 240 is changed, the same results as those of the relationships shown in fig. 4 and 5 can be obtained with respect to the energy conversion efficiency with respect to the discharge amount. When the number of stages of the diffuser 250 and the impeller 240 is three or more, the efficiency curves of the impeller 240 and the diffuser 250 after the third stage are the same as the second-stage efficiency curves (see thick dashed lines in fig. 4 and 5).
In the multistage pump device 10 of the present embodiment described above, the unit change amount Δ xc (mm) of the blade angle β w of the plurality of diffuser blade portions 280 with respect to the meridian plane position on the outer circumferential side or the inner circumferential side changes in all regions by the change amount Δ β w satisfying the relationship of equation (1). In addition, the wing angle β w of the diffuser wing 280 is formed to be less than 90 ° in all regions. Accordingly, the rotation speed component remains in the outlet fluid of the diffuser 250, and the outlet fluid of each diffuser 250 can be stabilized regardless of the pump flow rate, so that the small-sized multi-stage pump device 10 having high energy conversion efficiency can be realized.
The maximum outer diameter Φ Dc and the maximum inner diameter Φ Dh of the flow path defined by the outer casing portion 270 and the inner casing portion 260, and the meridian vane lengths Lc and Lh on the outer circumferential side and the inner circumferential side of the diffuser vane portion 280 satisfy the relationships expressed by expressions (2) to (4). The angle θ o between the outer peripheral surface of the outflow-side end of the inner case 260 and the axis Aw satisfies the relation of equation (5) with respect to the specific speed Ns. However, the diffuser vanes 280 are not limited to this example, and may satisfy at least one of the expressions (2) to (5) in the above-described relationship.
In the multistage pump device 10 described above, the motor 100 is provided below and the pump section 200 is provided above the motor 100, but the motor 100 may be provided above the pump section 200. As shown in fig. 1, pump unit 200 is not limited to a vertical position, and may be a horizontal position. The multistage pump device 10 may be used in water or on land.
In the diffuser 250, 7 diffuser vanes 280 are provided between the inner case 260 and the outer case 270, but the number of the diffuser vanes 280 may be 1 to 6, or 8 or more.
The diffuser 250 described above houses the impeller 240, but a casing that houses the impeller 240 may be provided separately from the diffuser 250.
In the multistage pump device 10 described above, the two-stage diffuser 250 and the impeller 240 are provided, but the diffuser 250 and the impeller 240 may be provided in three or more stages.
The embodiments of the present invention have been described above, but the embodiments of the present invention described above are not intended to limit the present invention, so that the present invention can be easily understood. The present invention can be modified and improved without departing from the gist thereof, and the present invention includes equivalents thereof. In addition, any combination of the embodiments and the modifications is possible within a range in which at least a part of the above-described problems can be solved or at least a part of the effects can be obtained, and any combination or omission of the respective constituent elements described in the claims and the specification is possible.
The present application claims priority based on japanese patent application No. 2016-. The entire disclosures including the specification, claims, drawings and abstract of japanese patent application No. 2016-. The present application is incorporated by reference in its entirety for all disclosures including the specification, claims, drawings, and abstract of japanese patent application laid-open No. 6-323291 (patent document 1).
Description of reference numerals: a multi-stage pump apparatus; a motor; a cable; a drive shaft; a joint; a housing; a pump section; a suction housing; an assembly portion; a small screw; a suction inlet; 218.. an assembly portion; discharging the housing; an assembly portion; an assembly portion; a check valve; a spindle; an impeller; a diffuser; an assembly portion; a small screw; an assembly portion; a small screw; 258.. liner ring; an inboard housing portion; 268. a bearing sleeve; an outer housing portion; a diffuser wing; aw.. axis; β w.. diffuser wing angle; rd.. circumferential tangent; cd.. centerline; fc.. a flow path; xc.. meridian plane position; phi Dc.. maximum outer diameter; phi Dh.. maximum inner diameter; ns.. specific speed; dh..

Claims (9)

1. A diffuser for a multistage pump, the diffuser being disposed concentrically with an impeller that rotates about a rotation axis and guiding a fluid that is induced by the rotation of the impeller, the diffuser comprising:
a housing section that divides a cylindrical flow path so that the diameter thereof becomes smaller from an inflow side toward an outflow side of a fluid; and
a plurality of diffuser blades arranged in the cylindrical flow passage to divide the cylindrical flow passage into a spiral shape,
a diffuser angle β w (°) that is an angle formed by a tangential direction of a blade surface of the diffuser wing portion and a circumferential direction with respect to the rotation axis, and a unit change amount Δ xc (mm) with respect to the meridian position, at an arbitrary meridian position of the casing, satisfy: the variation amount Delta beta w of the relation Delta beta w < 2.4. Delta Xc is changed,
the diffuser vane angle β w is less than 90 ° in all regions.
2. The diffuser of claim 1,
the maximum outer diameter φ Dc of the flow path defined by the housing section and the meridian blade length Lc on the outer peripheral side of the diffuser blade section satisfy: lc/φ Dc < 0.64.
3. The diffuser of claim 1,
the maximum inner diameter phi Dh of the flow path divided by the casing part and the meridian plane wing length Lh of the inner circumferential side of the diffuser wing part satisfy: lh/φ Dh is less than 0.63.
4. The diffuser of claim 2,
the maximum inner diameter phi Dh of the flow path divided by the casing part and the meridian plane wing length Lh of the inner circumferential side of the diffuser wing part satisfy: lh/φ Dh is less than 0.63.
5. The diffuser of any one of claims 1 to 4,
the meridian plane wing length Lh on the inner peripheral side of the diffuser wing part is equal to or less than the meridian plane wing length Lc on the outer peripheral side.
6. The diffuser of any one of claims 1 to 4,
the rotational speed (min) of the pump-1) Np is the discharge amount (m)3Min) is Qp, a total head (m) is Hp, a wall surface on an inner peripheral side of the outflow-side end portion of the case portion is located on a downstream side of a position where an inner diameter of the flow path is maximum, and a maximum value θ o (°) of an angle formed with the rotation axis is (Np · Qp) with respect to Ns used1/2)/Hp3/4The specific speed Ns indicated satisfies:
θo＞1500·Ns-0.6the relationship (2) of (c).
7. The diffuser of claim 5,
the rotational speed (min) of the pump-1) Np is the discharge amount (m)3Min) is Qp, a total head (m) is Hp, a wall surface on an inner peripheral side of the outflow-side end portion of the case portion is located on a downstream side of a position where an inner diameter of the flow path is maximum, and a maximum value θ o (°) of an angle formed with the rotation axis is (Np · Qp) with respect to Ns used1/2)/Hp3/4The specific speed Ns indicated satisfies:
θo＞1500·Ns-0.6the relationship (2) of (c).
8. A multistage pump device is provided with:
a diffuser as claimed in any one of claims 1 to 7 in multiple stages; and
an impeller having a plurality of stages arranged concentrically with the diffuser and inducing a fluid toward the diffuser.
9. The multi-stage pump arrangement of claim 8,
the device further comprises a power source for rotating the impeller.
CN201780014161.8A 2016-03-29 2017-03-29 Diffuser and multistage pump device Active CN108700078B (en)

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PCT/JP2017/012812 WO2017170640A1 (en) 2016-03-29 2017-03-29 Diffuser and multistage pump

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US10760587B2 (en) * 2017-06-06 2020-09-01 Elliott Company Extended sculpted twisted return channel vane arrangement
US11181123B2 (en) * 2019-03-22 2021-11-23 Apergy Esp Systems, Llc Downhole centrifugal pump diffuser with protuberant vanes
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KR20130060778A (en) * 2011-11-30 2013-06-10 에스티엑스중공업 주식회사 Diffuser pump

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