Open impeller for submersible pumps configured to pump liquids containing abrasive materials
By adjusting the position and size of the winglets in the open impeller, the problems of blade lower edge wear and increased power consumption were solved, resulting in more efficient flow and a longer impeller life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XYLEM EURO GMBH
- Filing Date
- 2021-09-20
- Publication Date
- 2026-04-17
AI Technical Summary
In the prior art, the gap design between the lower edge of the impeller blades and the wear-resistant plate leads to increased power consumption, reduced flow area, reduced efficiency, and severe blade wear, especially in high pressure differential areas.
Design an open impeller with winglets located radially outside the inner radius of the impeller, extending circumferentially to the trailing edge of the blade suction side, and increasing the gap width at the larger diameter of the impeller to reduce crossflow and wear. Flow and wear are optimized by adjusting the width and thickness of the winglets.
It effectively reduces blade wear, maintains impeller efficiency and flow area, extends impeller life, and reduces power consumption.
Smart Images
Figure CN116194674B_ABST
Abstract
Description
Technical Field
[0001] This invention generally relates to the field of pumps configured to pump liquids comprising solids / abrasives. More specifically, this invention relates to the field of submersible pumps, such as wastewater pumps and drainage pumps, particularly configured for pumping liquids comprising sand and gravel, such as wastewater, drilling water in mining / tunneling applications, surface water on construction sites, etc., i.e., transportation and drainage applications. Specifically, this invention relates to open impellers suitable for said pumps and applications, and submersible pumps including such open impellers.
[0002] An open impeller includes a cover plate, a centrally located hub, and at least two helical swept blades connected to the cover plate and the hub. Each blade includes a leading edge adjacent to the hub, a trailing edge located on the periphery of the impeller, and a lower edge, wherein the lower edge extends from the leading edge to the trailing edge and separates the suction side of the blade from the pressure side of the blade. The lower edge is configured to face and oppose a wear plate of the submersible pump. At least one blade includes a winglet at the lower edge, wherein the winglet is connected to and protrudes from the suction side of the at least one blade. Background Technology
[0003] In applications such as mining, tunneling, quarrying, and construction sites, it is almost always necessary to remove excess water to ensure the working environment is sufficiently dry. In mining / tunneling / quarrying applications, large amounts of drilling water are used during pre-blasting loading and to prevent the spread of dust after blasting. If production water is not removed, it will at least flood the blast site and the lower part of the mine. Surface water and groundwater also accumulate, requiring the removal of excess water. Typically, drainage / dewatering pumps are used to lift water from the mine shaft to sedimentation tanks located above ground, or progressively from the lower part of the mine shaft to different sedimentation tanks / pits at different depths. Each step / lift can, for example, range from 25 to 50 meters vertically, and the length of the outlet conduit in each step or lift, i.e., the conveying distance, can, for example, range from 100 to 300 meters. In mining applications, a significant amount of sand and gravel material is suspended in the water, up to 10% in some applications. In addition to wastewater, wastewater pumping stations also handle sand, stones, and other abrasives, especially those from surface water.
[0004] Therefore, there are several applications where the pumped medium is highly abrasive, including sand, stones, etc. The applications discussed in this patent application are not so-called "vortex pumps," i.e., pumps with a large distance between the impeller and the wear plate of the volute, but rather pumps constructed such that there is only a small axial gap / slit between the lower edge of the impeller blades and the upper surface of the wear plate of the volute (pump housing), typically less than 1 mm. The gaps in "vortex pumps" are several centimeters, and these pumps are not affected by the problem addressed by this invention.
[0005] In all pump applications, a pressure difference exists between the suction side (radially inward) and the pressure side (radially outward) of the blades due to impeller design and rotation. Most dewatering pumps are so-called high-pressure pumps, where this pressure difference across the blades can be very high. This pressure difference across the blades, or across the lower edge clearance, causes a jet of the medium (i.e., liquids and abrasives) to be ejected from the pressure side through the narrow gap between the lower edge of the blade and the wear plate towards the suction side. The jet of pumped medium through this gap will wear down the lower edge of the blades, and the resulting increase in clearance distance will lead to a rapid decrease in performance and efficiency, namely, reduced head, decreased pumping flow rate, and increased power consumption.
[0006] Known prior art pumps have so-called winglets at the lower edge of the impeller blades and a small axial clearance between the impeller and the wear plate, as in document US7037069, to increase the length of the clearance between the lower edge of the blades and the wear plate / suction cover of the pump volute. This document includes an acute angle between the winglet and the central axis of the impeller, and the winglet is located on the pressure side of the blade. Other known impellers have winglets located on the suction side of the blades, such as GB2175963, but these disclose vortex pumps / impellers. Prior art solutions disclose the use of winglets along the entire lower edge of the blade, i.e., from the hub to the periphery, and according to US7037069, the width of the winglet should decrease towards the periphery of the impeller.
[0007] The inventors of this invention have discovered a serious problem with known winglet solutions: the increased wetted area between the impeller's lower edge and the wear plate due to the winglets leads to increased power consumption, and reducing power consumption is a general problem / focus in the field of pump technology. Therefore, the inventors have recognized that using winglets along the entire length of the blade from leading to trailing edge will result in an unnecessarily large total wetted area between the impeller and the wear plate, i.e., a clearance area perpendicular to the axial distance between the impeller and the wear plate, leading to increased pump power consumption. Consequently, when using winglets extending from the leading to trailing edge of the blade, the flow area of the impeller passage and the effective blade height will also decrease radially inward. This reduction in flow area and effective blade height will negatively impact impeller efficiency. Therefore, the inventors proposed this invention due to the aforementioned drawbacks and based on the understanding that blade wear is more severe at larger impeller diameters, due to the increased pressure differential at larger impeller diameters and the increased relative velocity between the blades and the wear plate at larger impeller diameters.
[0008] The purpose of this invention
[0009] The present invention aims to eliminate the aforementioned drawbacks and malfunctions of previously known impellers and pumps, and to provide an improved impeller and pump. The main objective of the invention is to provide an improved impeller of an initially defined type, comprising a winglet configured to absorb wear on the lower edge of the blades and thereby reduce crossflow on the blades, thus maintaining efficiency, i.e., increasing the beneficial effects of using the winglet, while reducing and minimizing the known negative effects of the winglet. Summary of the Invention
[0010] According to the present invention, at least the primary objective is achieved by an initially defined open impeller and submersible pump having the features defined by the present invention. The present invention further defines preferred embodiments of the invention.
[0011] According to a first aspect of the invention, an open impeller of an initial defined type is provided, characterized in that the winglet is located radially outside the inner radius (r_inner) of the impeller and extends circumferentially to the trailing edge of the blade suction side located at the maximum radius (r_max) of the impeller, the winglet having a lower wear surface configured to face and opposite a wear plate of a submersible pump, wherein the inner radius (r_inner) is equal to the maximum value of the following:
[0012] - The maximum radius of the impeller (r_max) multiplied by 0.6, and
[0013] - Multiply the impeller inlet radius (r_inlet) by 1.2, where the inlet radius (r_inlet) is taken at the interface between the leading edge and the lower edge of the blade on the suction side of the blade.
[0014] According to a second aspect of the invention, a submersible pump is provided, which includes such an open impeller.
[0015] Therefore, this invention is based on the understanding that the winglets should not begin at the leading edge of the blade, i.e., at the inlet of the pump volute, so as not to negatively affect the flow of the pumped liquid inside the impeller passage. Furthermore, based on the view that larger impeller diameters result in more severe wear, larger impeller diameters require more winglets. Simultaneously, the wetted area of the gap should be minimized to minimize power consumption. The longer the gap at the point of maximum pressure difference, the less crossflow and the less wear.
[0016] According to various embodiments of the invention, the width (W) of the lower wear surface of the winglet, obtained along the impeller radius, increases from zero at the inner radius (r_inner) to a maximum width (W_max) at the suction-side trailing edge of the blade. Therefore, in addition to the original clearance width at the blade's lower edge, the increased clearance width via the winglet increases with the radius, thus minimizing crossflow and wear under conditions of maximum pressure differential.
[0017] According to various embodiments of the invention, the impeller blades have a height (H) at the maximum width (W_max) of the blade, wherein when the height (H) is greater than 50 mm, the ratio of the maximum width (W_max) of the lower wear surface of the blade to the blade height (H) is equal to or greater than 0.4 and equal to or less than 0.6, and when the height (H) is equal to or less than 50 mm, it is equal to or greater than 0.5 and equal to or less than 0.8. Therefore, the width of the blade is suitable for different impellers configured to handle different pressure differentials, i.e., impellers configured to provide higher pressure / head (i.e., smaller effective blade height and higher pressure differential), and blades wider than those of the impellers configured to provide lower pressure / head (i.e., larger effective blade height and lower pressure differential).
[0018] According to various embodiments of the invention, the thickness (T) of the winglet is equal to or greater than 2.5 mm and equal to or less than 7 mm. According to various embodiments of the invention, the width (T) of the winglet is maximum at the maximum width (W_max) of the lower wear surface of the winglet. Therefore, a large portion of the winglet material is added where wear is more severe and the impeller channel has the largest flow area, i.e., where the impact on the flow area of the channel is smaller.
[0019] Further advantages and features of the present invention will become apparent from the following detailed description of preferred embodiments. Attached Figure Description
[0020] The above and other features and advantages of the present invention will be clearly understood from the following detailed description of preferred embodiments in conjunction with the accompanying drawings, wherein:
[0021] Figure 1 This is a schematic cross-sectional side view of the hydraulic unit of the submersible pump (i.e., drainage pump) of the present invention, including the open impeller of the present invention.
[0022] Figure 2 This is a schematic perspective view from below of an open impeller with two blades, an example of an impeller used in a wastewater pump configured for lower pressure and higher volume.
[0023] Figure 3 From the basis Figure 2 The diagram shown below the impeller.
[0024] Figure 4 It is based on Figure 2 and Figure 3 A schematic cross-sectional side view of the impeller.
[0025] Figure 5This is a schematic perspective view from below of an open impeller with three blades, an example of an impeller used in a drainage pump configured for medium pressure and medium volume.
[0026] Figure 6 From the basis Figure 5 The diagram shown below the impeller.
[0027] Figure 7 It is based on Figure 5 and Figure 6 A schematic cross-sectional side view of the impeller.
[0028] Figure 8 This is a schematic perspective view from below of an open impeller with four blades, an example of an impeller used in a drainage pump configured for higher pressure and lower volume.
[0029] Figure 9 From the basis Figure 8 The diagram shown below the impeller, and
[0030] Figure 10 It is based on Figure 8 and Figure 9 A schematic cross-sectional side view of the impeller. Detailed Implementation
[0031] This invention specifically relates to the field of submersible pumps, which are particularly configured for pumping liquids containing abrasive / solid materials, such as water comprising sand and stone materials. Submersible pumps are especially wastewater pumps and drainage / dehydration pumps. This invention specifically relates to an open impeller suitable for such pumps and such applications.
[0032] First refer to Figure 1 , Figure 1 A schematic diagram of the hydraulic unit of the submersible pump is disclosed, generally represented by 1. (See reference...) Figure 1 Describing a typical submersible pump, although Figure 1 The hydraulic unit of the drainage pump is actually disclosed, but the structural components are the same for the wastewater pump. Submersible pump 1 is referred to as the pump below.
[0033] The hydraulic unit of pump 1 includes an inlet 2, an outlet 3, and a volute 4 located between the inlet 2 and the outlet 3, i.e., the volute 4 is located downstream of the inlet 2 and upstream of the outlet 3. The volute 4 is partially defined by a wear-resistant plate 5 surrounding the inlet 2. The volute 4 is also connected to the drive unit of pump 1 (from...) Figure 1The intermediate wall 6 is separated from the pump housing (removed from the center). The volute 4 is also referred to as the pump chamber, and the wear plate 5 is also referred to as the suction cover. In some applications, the outlet 3 of the hydraulic unit also constitutes the outlet of the pump 1, and in other applications, the outlet 3 of the hydraulic unit is connected to a separate outlet of the pump 1. The outlet of the pump 1 is configured to be connected to an outlet conduit (not shown). Thus, the pump 1 includes an open impeller, generally indicated by 7, wherein the impeller 7 is located in the volute 4, i.e., the hydraulic unit of the pump 1 includes the impeller 7.
[0034] The hydraulic unit of the drain pump includes an inlet filter 8 with perforations or holes 9, wherein the inlet filter 8 is configured to prevent larger objects from reaching the inlet 2 and the volute 4. Otherwise, such larger objects may clog or block the impeller 7.
[0035] The drive unit of pump 1 includes an electric motor arranged in a liquid-tight pump housing and a drive shaft 10 extending from the electric motor through the intermediate wall 6 and into the volute 4. During operation of pump 1, an impeller 7 is connected to and driven to rotate by the drive shaft 10, wherein when pump 1 is running, liquid is drawn into the inlet 2 and pumped out from the outlet 3 through the rotating impeller 7. The pump housing, wear plate 5, impeller 7, and other basic components are preferably made of metal, such as aluminum and steel. The electric motor is powered by an electrical cable extending from a power source, and pump 1 includes a liquid-tight lead that receives the electrical cable.
[0036] According to a preferred embodiment, pump 1 (more precisely, electric motor) is operatively connected to a control unit, such as a smart drive including a variable frequency drive (VFD). Therefore, pump 1 is configured to operate at a variable operating speed [rpm] via the control unit. According to a preferred embodiment, the control unit is located inside the liquid-tight pump housing, i.e., preferably integrated into pump 1. The control unit is configured to control the operating speed of pump 1. According to an alternative embodiment, the control unit is an external control unit, or the control unit is separated into an external subunit and an internal subunit. The operating speed of pump 1 is more precisely the rotational speed of the electric motor and impeller 7, and corresponds to or is related to the output frequency of the control unit.
[0037] The components of pump 1 are typically cooled by the liquid / water surrounding pump 1. Pump 1 is designed and configured to operate in an immersion configuration / position, i.e., completely below the liquid surface during operation. However, it should be recognized that submersible pump 1 does not necessarily need to be completely below the liquid surface during operation, but may be continuously or occasionally completely or partially above the liquid surface. In dry-installation applications, submersible pump 1 includes a dedicated cooling system.
[0038] This invention is based on a novel and improved open impeller 7 configured for use in a pump 1 to pump abrasive media (e.g., water or wastewater / sewage containing sand and stones). Due to the pumping of solid / abrasive substances in the liquid, the impeller 7 wears very quickly in such devices and typically needs to be replaced every 7 weeks under rough conditions because the efficiency of the pump 1 decreases rapidly as the impeller 7 wears. Tests have shown that this invention extends the replacement requirement by approximately 30-50% compared to conventional impellers without the fins of this invention.
[0039] Different examples of the impeller 7 of the present invention are now disclosed with reference to the present invention. Figure 2-10 , Figure 2-4 The first example impeller has been disclosed. Figure 5-7 A second example impeller was disclosed, and Figure 8-10 A third example impeller is disclosed. Unless otherwise stated, the following description applies to all impellers 7 of the present invention, regardless of which figure is referenced.
[0040] The impeller 7 includes a cover plate 11, a centrally located hub 12, and at least two helical swept blades 13 connected to the cover plate 11 and the hub 12. Figure 2-4 In the middle, the impeller 7 includes two blades 13, in Figure 5-7 The impeller 7 includes three blades 13; in Figure 8-10 The intermediate impeller 7 contains four blades 13. The blades 13 are equidistantly positioned around the hub 12.
[0041] Viewed from the hub 12 toward the outer periphery of the impeller 7, during normal (liquid pumping) operation of the pump 1, the blades 13 are swept in the opposite direction to the rotation of the impeller 7. Therefore, from below (i.e.) Figure 3 , 6 (See 9) Impeller 7 rotates counterclockwise during normal operation.
[0042] Each blade 13 includes a leading edge 14 adjacent to the hub 12 and a trailing edge 15 located around the periphery of the impeller 7. The leading edge 14 of the impeller 7 is upstream of the trailing edge 15, wherein two adjacent blades 13 together define a channel extending from the leading edge 14 to the trailing edge 15. The leading edge 14 is located at the inlet 2 of the hydraulic unit and spirals outward from the hub in the same direction as the blades 13. During operation, the leading edge 14 grabs the liquid, the channel accelerates the liquid, and the liquid exits the impeller 7 at the trailing edge 15. Thereafter, the liquid is guided by the volute 4 of the hydraulic unit toward the outlet 3. Thus, liquid is drawn into the impeller 7 and expelled from the impeller 7. The channel is also defined by the cover plate 11 of the impeller 7 and the wear plate 5 of the volute 4. The diameter of the impeller 7 and the shape and construction of the channel / blades determine the pressure accumulation in the liquid and pumped flow.
[0043] Each blade 13 also includes a lower edge 16, which extends from the leading edge 14 to the trailing edge 15 and separates the suction side / surface 17 of the blade 13 from the pressure side / surface 18 of the blade 13. The lower edge 16 is configured to face and oppose the wear plate 5 of the pump 1. Thus, the suction side 17 of one blade 13 is opposite to the pressure side 18 of the adjacent blade 13. The leading edge 14 and the trailing edge 15 also separate the suction side 17 from the pressure side 18. The leading edge 14 is preferably rounded.
[0044] At least one blade 13 includes a winglet 19 at its lower edge 16, wherein the winglet 19 is connected to and protrudes from the suction side 17 of the blade 13. The winglet 19 has a lower wear surface 20, which is configured to face and oppose the wear plate 4 of the pump 1. The lower wear surface 20 of the winglet 19 is preferably flush with the lower edge 16 of the blade 13.
[0045] Importantly, the winglet 19 is located radially outside the inner radius (r_inner) of the impeller 7 and extends circumferentially to the trailing edge 15 at the suction side 17 of the blade 13 located at the maximum radius (r_max) of the impeller 7. Therefore, the invention is based on the understanding that the starting point of the winglet 19, i.e., the inner radius (r_inner), should be far from the inlet 2, i.e., far from the interface between the leading edge 14 and the lower edge 16 of the blade 13. The inner radius (r_inner) is equal to the maximum value of the following:
[0046] - The maximum radius of impeller 7 (r_max) multiplied by 0.6, and
[0047] - Multiply the inlet radius (r_inlet) of impeller 7 by 1.2.
[0048] The inlet radius (r_inlet) is obtained at the interface between the leading edge 14 and the lower edge 16 of the blade 13 on the suction side 17 of the blade 13.
[0049] exist Figure 3 , Figure 6 and Figure 9 In the image, the interface between the lower wear surface 20 of the winglet 19 and the lower edge 16 of the blade 13 is shown by dashed line 21, and it is clear that the winglet 19 begins at a certain distance from the leading edge 14.
[0050] The technical function of the winglet 19 is to increase the width of the gap between the lower edge 16 of the blade 13 and the wear plate 5, thereby reducing the crossflow of liquid and abrasive from the pressure side 18 to the suction side 17, and thus reducing the wear of the blade 13. However, increasing the gap width also increases the wetted area of the gap, resulting in increased friction. The wetted area of the gap is the portion of the blade 13 that faces and is opposite to the wear plate 5. By moving the starting point of the winglet 19 away from the leading edge 14, the width of the gap at the larger diameter of the impeller 7, i.e., the width of the winglet 19, can be increased without increasing the wetted area of the gap, and by increasing the width of the gap at the larger diameter of the impeller 7, the impeller 7 will be more wear-resistant.
[0051] Preferably, all blades 13 of the impeller 7 are provided with small winglets 19 of the same size so as to have a balanced impeller 7.
[0052] According to various embodiments, the width (W) of the lower wear surface 20 of the winglet 19 increases along the diameter of the impeller 7 from zero at the inner radius (r_inner) to a maximum width (W_max) at the trailing edge 15 of the suction side 17 of the blade 13. The blade 13 of the impeller 7 has a height (H) at the maximum width (W_max) of the winglet 19, which is measured along a straight line perpendicular to an imaginary line coinciding with the lower edge 16 of the blade 13, and the height is measured between the imaginary interface between the suction side 17 of the blade 13 and the lower surface 22 of the cover plate 11 and the imaginary line. The blade height can vary depending on the distance from the central axis of the impeller 7.
[0053] According to a preferred embodiment, when the height (H) is greater than 50 mm, the ratio between the maximum width (W_max) of the lower wear surface 20 of the winglet 19 and the height (H) of the blade 13 is equal to or greater than 0.4 and equal to or less than 0.6. This is, for example, used for an impeller 7 configured for a drainage pump.
[0054] According to other preferred embodiments, when the height (H) is equal to or less than 50 mm, the ratio between the maximum width (W_max) of the lower wear surface 20 of the winglet 19 and the height (H) of the blade 13 is equal to or greater than 0.5 and equal to or less than 0.8. This is, for example, used for an impeller 7 configured for a wastewater pump.
[0055] The maximum width (W_max) of the lower wear surface 20 of the winglet 19 is measured parallel to the lower wear surface 20 and from an imaginary interface between the suction side 17 of the blade 13 and the upper surface 23 of the winglet 19. The upper surface 23 of the winglet 19 is opposite to the lower wear surface 20 of the winglet 19.
[0056] According to various embodiments, the thickness (T) of the winglet 19 is equal to or greater than 2.5 mm and equal to or less than 7 mm, preferably equal to or greater than 3 mm and equal to or less than 6 mm. A winglet 19 that is too thin will be deformed, while a winglet 19 that is too thick will negatively affect the effective flow area of the impeller 7 channel and the weight of the impeller 7, and thus negatively affect the efficiency of the pump 1.
[0057] According to a preferred embodiment, at the maximum radius (r_max) of the impeller 7, the thickness (T) of the winglet 19 is greatest at the maximum width (W_max) of the lower wear surface 20 of the winglet 19. It is also preferable that the thickness (T) of the winglet 19 increases circumferentially along the winglet 19. Therefore, the winglet 19 is thicker at its outermost portion, i.e., in the area where the winglet 19 experiences the greatest wear and force.
[0058] Another way to define the thickness (T) of the winglet 19 is in relation to the height (H) of the blade 13. Therefore, the ratio between the thickness (T) of the winglet 19 and the height (H) of the blade 13 at the maximum width (W_max) of the lower wear surface 20 of the winglet 19 is equal to or greater than 0.05 and equal to or less than 0.3.
[0059] For all impellers 7, the angle (α) between the lower wear surface 20 of the winglet 19 and the central axis of the impeller 7 is blunt, i.e. greater than 45 degrees.
[0060] The distance between the lower wear surface 20 of the wing 19 and the wear plate 5 is equal to or greater than 0.1 mm and equal to or less than 0.5 mm, preferably equal to or greater than 0.15 mm and preferably equal to or less than 0.4 mm.
[0061] Feasible modifications to the present invention
[0062] This invention is not limited to the embodiments shown above and in the accompanying drawings, which are primarily illustrative and exemplary. This patent application is intended to cover all modifications and variations of the preferred embodiments described herein, and therefore the invention is defined by the wording of the appended claims. Consequently, the device can be modified in various ways within the scope of the appended claims.
[0063] It should also be noted that all information regarding / involving terms, such as "above," "below," etc., should be interpreted / read in accordance with the drawings and the drawings should be oriented accordingly for proper reading of the references. Therefore, these terms only indicate the relationships in the illustrated embodiments, and these relationships may be altered if the device of the present invention has other structures / designs.
[0064] It should also be noted that, even so, there is no explicit statement that features from a particular embodiment can be combined with features from another embodiment, and if such combination is possible, it should be considered obvious.
Claims
1. An open impeller (7) for a submersible pump (1) configured to pump a liquid comprising abrasive, the impeller (7) comprising a cover plate (11), a centrally located hub (12) and at least two helical swept blades (13) connected to the cover plate (11) and the hub (12). Each blade (13) includes a leading edge (14) adjacent to the hub (12), a trailing edge (15) located on the periphery of the impeller (7), and a lower edge (16), wherein the lower edge (16) extends from the leading edge (14) to the trailing edge (15) and separates the suction side (17) of the blade (13) from the pressure side (18) of the blade (13), and wherein the lower edge (16) is configured to face and be opposite to the wear plate (5) of the submersible pump (1). At least one blade (13) includes a winglet (19) at its lower edge (16), wherein the winglet (19) is connected to and protrudes from the suction side (17) of the at least one blade (13). Its features are, The winglet (19) is located radially outside the inner radius (r_inner) of the impeller (7) and extends circumferentially to the trailing edge (15) at the suction side (17) of the blade (13) located at the maximum radius (r_max) of the impeller (7). The winglet (19) has a lower wear surface (20), which is configured to face and be opposite to the wear plate (5) of the submersible pump (1). The inner radius (r_inner) is equal to the maximum value of the following: - The maximum radius (r_max) of the impeller (7) multiplied by 0.6, and - The inlet radius (r_inlet) of the impeller (7) is multiplied by 1.2, wherein the inlet radius (r_inlet) is obtained at the interface between the leading edge (14) and the lower edge (16) of the blade (13) on the suction side (17) of the blade (13).
2. Open impeller (7) according to claim 1, wherein The lower wear surface (20) of the winglet (19) is flush with the lower edge (16) of the blade (13).
3. The open impeller (7) according to claim 1, wherein, The width (W) of the lower wear surface (20) of the winglet (19) obtained along the diameter of the impeller (7) increases from zero at the inner radius (r_inner) to the maximum width (W_max) at the trailing edge (15) of the suction side (17) of the blade (13).
4. The open impeller (7) according to claim 3, wherein, The blades (13) of the impeller (7) have a height (H) at the maximum width (W_max) of the winglet (19).
5. The open impeller (7) according to claim 4, wherein, The height (H) is measured along a straight line that extends perpendicularly to an imaginary line that coincides with the lower edge (16) of the blade (13), and is measured between the imaginary interface between the suction side (17) of the blade (13) and the lower surface (22) of the cover plate (11) and the imaginary line.
6. The open impeller (7) according to claim 4, wherein, When the height (H) is greater than 50 mm, the ratio of the maximum width (W_max) of the lower wear surface (20) of the winglet (19) to the height (H) of the blade (13) is equal to or greater than 0.4 and equal to or less than 0.
6.
7. The open impeller (7) according to any one of claims 4-6, wherein, When the height (H) is equal to or less than 50 mm, the ratio of the maximum width (W_max) of the lower wear surface (20) of the winglet (19) to the height (H) of the blade (13) is equal to or greater than 0.5 and equal to or less than 0.
8.
8. The open impeller (7) according to any one of claims 3-6, wherein, The maximum width (W_max) of the lower wear surface (20) of the winglet (19) is measured parallel to the lower wear surface (20) and from the imaginary interface between the suction side (17) of the blade (13) and the upper surface (23) of the winglet (19).
9. The open impeller (7) according to claim 1, wherein, The thickness (T) of the winglet (19) is equal to or greater than 2.5 mm and equal to or less than 7 mm.
10. The open impeller (7) according to claim 9, wherein, At the maximum radius (r_max) of the impeller (7), the thickness (T) of the winglet (19) is at the maximum width (W_max) of the lower wear surface (20) of the winglet (19).
11. The open impeller (7) according to claim 9 or 10, wherein, The thickness (T) of the winglet (19) increases in the circumferential direction along the winglet (19).
12. The open impeller (7) according to claim 4, wherein, The ratio between the thickness (T) of the winglet (19) and the height (H) of the blade (13) obtained at the maximum width (W_max) of the lower wear surface (20) of the winglet (19) is equal to or greater than 0.05 and equal to or less than 0.
3.
13. The open impeller (7) according to any one of claims 1-6, wherein, The angle (α) between the lower wear surface (20) of the winglet (19) and the central axis of the impeller (7) is blunt.
14. The open impeller (7) according to claim 1, wherein, The thickness (T) of the winglet (19) is equal to or greater than 3 mm and equal to or less than 6 mm.
15. A submersible pump (1) configured for pumping a liquid comprising abrasive, the submersible pump (1) comprising a hydraulic unit having an inlet (2), an outlet (3), and a volute (4) located between the inlet (2) and the outlet (3), wherein, The volute (4) is partially defined by a wear-resistant plate (5) surrounding the inlet (2), characterized in that the submersible pump (1) includes an open impeller (7) according to any one of claims 1-14.
16. The submersible pump (1) according to claim 15, wherein, The distance between the lower wear surface (20) of the winglet (19) and the wear plate (5) is equal to or greater than 0.1 mm and equal to or less than 0.5 mm.
17. The submersible pump (1) according to claim 15, wherein, The distance between the lower wear surface (20) of the winglet (19) and the wear plate (5) is equal to or greater than 0.15 mm and equal to or less than 0.4 mm.
Citation Information
Patent Citations
Impeller for a pump, especially a vortex pump
GB2175963A
Impeller and wear plate
US7037069B2
impeller
EP1747377A1
Centrifugal pump
JP2015175278A