Impeller seat for a pump

Abstract

The present invention relates to an impeller housing (5) for a pump, the impeller housing (5) having an inlet wall, wherein the impeller housing (5) has an inlet radius measured from an axially extending central axis (A) to a circular intersection (11) between the inlet wall and the upper surface (12) of the impeller housing (5), the impeller housing (5) including a guide pin (13) connected to and extending radially inward from the inlet wall, the guide pin (13) having an end radius measured from the axially extending central axis (A) to the radially innermost portion of the guide pin (13), wherein an imaginary 15% circle (23) is radially offset from the circular intersection (11) by fifteen percent of the difference between the inlet radius (R) and the end radius (r), the impeller housing (5) including a feed groove (14) arranged in the upper surface (12) of the impeller housing (5) and extending from the inlet wall (10) to the periphery of the impeller housing (5). The impeller seat (5) is characterized in that, viewed from the direction of rotation of the pump (1), the upstream edge line (34) of the slot inlet is the radius at which the impeller seat (5) intersects with the upstream edge (35) of the feed slot (14) at the circular intersection (11), wherein the upstream edge angle (λ) of the slot inlet between the radius at which the impeller seat (5) intersects with the upstream edge of the guide pin (13) at the 15% circle (23) viewed from the direction of rotation of the pump (1) and the upstream edge line (34) of the slot inlet is equal to or less than 20 degrees and equal to or greater than 0 degrees. The invention also relates to pumps comprising such an impeller seat.

Description

Technical Field

[0001] This invention generally relates to the field of pumps configured to pump liquids containing solid substances. Furthermore, the invention relates to the field of submersible pumps, such as sewage / wastewater pumps, particularly those configured to pump liquids such as sewage / wastewater, which may contain polymers, hygiene products, fabrics, rags, disposable gloves, face masks, etc. The invention particularly relates to impeller housings suitable for said pumps and applications, and pumps including such impeller housings and open impellers. The impeller housing of a pump is also technically referred to as a suction cover and inlet insert.

[0002] According to a first aspect, the present invention relates to an impeller housing having an axial inlet defined by an inlet wall and an upper surface located downstream of the axial inlet, wherein the impeller housing has an inlet radius (R) measured from an axially extending central axis (A) to a circular intersection between the inlet wall and the upper surface of the impeller housing. The impeller housing includes a guide pin connected to and extending radially inward from the inlet wall, the guide pin having an end radius (r) measured from the axially extending central axis (A) to the radially innermost portion of the guide pin, wherein an imaginary 15% circle is radially offset inward from the circular intersection by fifteen percent of the difference between the inlet radius (R) and the end radius (r), and the impeller housing includes a feed groove arranged in the upper surface of the impeller housing and extending from the inlet wall to the periphery of the impeller housing.

[0003] According to a second aspect, the present invention relates to a pump comprising an open impeller having a cover plate, a centrally located hub, and at least two spirally swept blades connected to the cover plate and the hub, wherein each blade of the impeller includes a leading edge adjacent to the hub and a trailing edge located at the periphery of the impeller, and a lower edge, wherein the lower edge extends from the leading edge to the trailing edge, separating the suction side of the blade from the pressure side of the blade. Background Technology

[0004] In places like sewage / wastewater treatment plants, septic tanks, wells, and pumping stations, solid materials / contaminants such as socks, sanitary napkins, paper, disposable diapers, disposable gloves, face masks, and rags can accumulate and obstruct pumps submerged in basins / pools, a phenomenon known as hard blockage. This means that solid material has entered the pump inlet and is preventing the impeller from rotating. Consequently, the pump becomes stuck due to some solid material trapped between the impeller and the pump casing / volute.

[0005] When the impeller and impeller seat are positioned at a fixed distance from each other, contaminants can sometimes be too large to easily pass through the pump. Large solid particles can, in the worst case, cause the impeller to jam, severely damaging the pump, such as bearings and drive units. This unintentional downtime is costly because it requires expensive, tedious, and unplanned maintenance.

[0006] European Patent EP 1357294 discloses a pump comprising an impeller arranged to rotate within a pump housing, the impeller being suspended by a drive shaft. The pump includes an impeller seat having a guide pin and a feed groove. The impeller is positioned at a fixed distance in the axial direction relative to the impeller seat. The guide pin is connected to the inlet wall of the impeller seat and extends straight toward the center of both the impeller and the impeller seat.

[0007] European Patent EP 1899609 discloses a pump that partially solves the problem of a fixed distance between the impeller and the impeller housing. The pump includes an impeller arranged to rotate within a pump housing, the impeller being suspended by a drive shaft, and an impeller housing with a guide pin and a feed groove. During pump operation, the impeller is axially movable relative to the impeller housing to allow the passage of larger solid materials that would otherwise clog the pump or be forced into the impeller. The guide pin is attached to the inlet wall of the impeller housing and extends straight toward the center of both the impeller and the impeller housing. The impeller is moved by the solid material as it enters the gap between the leading edge of the blade and the guide pin and / or the gap between the lower edge of the blade and the upper surface of the impeller housing.

[0008] Such pumps and applications are also protected by appropriate monitoring and control units that monitor pump operation and control it accordingly. For example, when the impeller speed decreases and / or power consumption increases, the impeller guide pins and / or volute become partially blocked, and the monitoring and control unit initiates a cleaning procedure that includes a step of reversing the impeller rotation, i.e., rotating it in the opposite direction to the impeller's rotation during normal pump operation.

[0009] This known pump features a large feed trough inlet located at the circular intersection between the inlet wall and the upper surface of the impeller housing. This ensures that solid material initially captured by the leading edge of the impeller blades and then scraped away by guide pins towards the inlet wall of the impeller housing readily enters the feed trough. It is then rapidly forced through the pump's volute due to the interaction between the lower edge of the impeller blades and the feed trough in the upper surface of the impeller housing. The large feed trough inlet is both high in the axial direction and long in the circumferential direction. Therefore, this design promotes both solid material capture and throughput.

[0010] However, the inventors have discovered that, particularly in applications with a large pressure difference between the pressure side and the suction side of the blade, the large inlet of the feed groove and the large cross-sectional area of ​​the first section of the feed groove result in a significant crossflow of liquid at the lower edge of the blade each time the blade passes through the feed groove. Therefore, as the lower edge of the blade passes through the first section of the feed groove, the liquid, which has already begun to move from the impeller seat inlet towards the periphery of the impeller seat while its pressure increases, is ejected towards the impeller seat inlet. This leakage, in the form of a liquid jet, is directed and counteracts the liquid flow drawn into the pump by the rotating impeller. Consequently, in some applications, at certain impeller rotation speeds, this liquid jet generates noise each time the lower edge of the blade passes through the first section of the feed groove.

[0011] Purpose of the invention

[0012] The purpose of this invention is to avoid the disadvantages and deficiencies of the previously known impeller housings and pumps, and to provide improved impeller housings and pumps.

[0013] The primary objective of this invention is to provide an improved impeller housing of an initially defined type that reduces or prevents the generation of liquid jets toward the impeller housing inlet, thereby reducing or preventing the aforementioned adverse effects of such jets. Summary of the Invention

[0014] According to the present invention, at least the primary objective is achieved by an initially defined impeller seat and pump having the features described below.

[0015] According to a first aspect of the invention, an impeller seat of an initial defined type is provided, characterized in that, viewed from the direction of pump rotation, the upstream edge line of the slot inlet is the radius of the impeller seat intersecting the upstream edge of the feed slot at the circular intersection, wherein the upstream edge angle of the slot inlet between the radius of the impeller seat intersecting the upstream edge of the guide pin at the 15% circle, viewed from the direction of pump rotation, and the upstream edge line of the slot inlet is equal to or less than 20 degrees and equal to or greater than 0 degrees, wherein the upstream edge line of the slot inlet at the circular intersection is located upstream of the radius of the impeller seat intersecting the upstream edge of the guide pin at the 15% circle, viewed from the direction of pump rotation, or coincides with the radius of the impeller seat intersecting the upstream edge of the guide pin at the 15% circle, viewed from the direction of pump rotation.

[0016] According to a second aspect of the invention, a pump of an initially defined type is provided, characterized in that the pump includes an impeller seat in which the leading edge of a blade is configured to cooperate with a guide pin of the impeller seat during pump operation, and the lower edge of the blade is positioned opposite the upper surface of the impeller seat.

[0017] Therefore, the present invention is based on the insight that by having a small inlet at the circular intersection between the inlet wall and the upper surface of the impeller seat (especially in the circumferential direction) viewed from the direction of pump / impeller rotation, with the feed groove upstream of the guide pin, when the lower edge of the impeller blade passes through the feed groove, the crossflow on the lower edge of the impeller blade will be guided toward the actual feed groove and / or guide pin, rather than toward the inlet of the impeller seat.

[0018] According to various embodiments of the invention, viewed from the direction of pump rotation, the downstream line of the feed groove inlet is the radius at which the impeller seat intersects the downstream edge of the feed groove inlet at the circular intersection, wherein the downstream edge angle of the feed groove inlet between the radius at which the impeller seat intersects the upstream edge of the guide pin at the 15% circle, viewed from the direction of pump rotation, and the downstream edge line of the feed groove inlet is equal to or greater than 15 degrees and equal to or less than 30 degrees. Therefore, the inlet of the feed groove is kept sufficiently large to capture solid material scraped off from the leading edge of the impeller blades by the leading edge of the guide pin.

[0019] According to various embodiments of the invention, the hypothetical 40% circle is radially offset inward from the intersection of the circles by forty percent of the difference between the inlet radius and the end radius, wherein the guide pin includes a leading edge configured to scrape contaminants from the pump impeller, wherein, viewed from the pump's rotational direction and from the axial direction, at least between the inlet wall and the 40% circle, the guide pin includes a pre-leading edge located upstream of the leading edge of the guide pin. Therefore, viewed circumferentially, the guide pin has a stepped structure, and since the stepped structure forms part of the inlet of the feed trough, solid material is more easily scraped off and captured by the feed trough.

[0020] According to various embodiments of the present invention, viewed from the direction of pump rotation, the downstream edge of the inlet of the feed trough is connected to the leading edge of the guide pin.

[0021] According to various embodiments of the invention, the imaginary 85% circle is radially offset inward from the intersection of the circles by eighty-five percent of the difference between the inlet radius and the end radius, and wherein the leading edge line is a projected straight line extending between the intersection of the 15% circle and the leading edge and the intersection of the 85% circle and the leading edge, and wherein the leading edge angle between the radius of the impeller seat intersecting the leading edge at the 15% circle and the leading edge line is equal to or greater than 10 degrees and equal to or less than 30 degrees.

[0022] An excessively large leading edge angle means that the distal / free end of the guide pin faces circumferentially, increasing the risk of solid material becoming lodged in it, leading to blockage and increased need for pump reverse operation. Unnecessary reverse operation, i.e., the impeller rotating in the opposite direction, wastes power without pumping liquid. An excessively small leading edge angle means that during normal pump operation, solid material will become entangled on the guide pin instead of being guided radially outward with the cooperation of the impeller's leading edge and the guide pin's leading edge. Therefore, an angled guide pin means the jet flow is directed towards the guide pin rather than towards the impeller seat inlet.

[0023] According to various embodiments of the invention, at least a portion of the upper surface of the guide pin is a planar surface, said at least a portion being defined by a 15% circle, an 85% circle, a leading edge, and a trailing edge. In this preferred embodiment, the planar surface has no curvature in the axial direction. Preferably, said at least a portion of the upper surface of the guide pin is inclined relative to a horizontal plane, wherein, viewed in the axial direction, the distal end of the guide pin is located upstream of the proximal end of the guide pin.

[0024] The planar upper surface of the guide pin means that the axial clearance between the leading edge of the impeller blades and the upper surface of the guide pin remains consistent when adjusting the axial clearance. In other words, the distance between the surfaces taken in the normal direction to the guide pin is uniform when the relative axial positions of the impeller and impeller seat are changed / adjusted / adjusted.

[0025] According to various embodiments of the invention, the axial distance between the pre-leading edge and the leading edge of the guide pin is greater than 1 mm and equal to or less than 4 mm. Therefore, the stepped configuration of the guide pin increases the likelihood that solid material can more easily enter the axial gap between the guide pin and the leading edge of the blade and enter the inlet of the feed groove.

[0026] According to various embodiments of the pump of the present invention, between the 15% circle and the 85% circle, the scraping angle (δ) between the projected tangent of the leading edge of the guide pin and the projected tangent of the intersection between the leading edge of the blade and the pressure side of the blade is greater than 90 degrees and equal to or less than 120 degrees, and wherein the leading edge of the blade is spirally swept from the hub of the impeller to the lower edge of the blade.

[0027] Therefore, solid material located between the leading edge of the guide pin and the leading edge of the blade will be scraped outward during normal pump operation (i.e., forward rotation of the impeller). Thus, this range will facilitate the scraping of solid material and hinder the cutting of solid material at the interface between the leading edge of the blade and the leading edge of the guide pin.

[0028] According to various embodiments of the pump of the present invention, the innermost radial portion of the guide pin is located radially outside the impeller hub. Therefore, no solid material can become stuck between the axial surface of the impeller hub and the upper surface of the distal end of the guide pin, and thus, solid material raked inward during reverse operation of the pump will more easily leave the guide pin.

[0029] Further advantages and features of the present invention will become apparent from the following detailed description of preferred embodiments. Attached Figure Description

[0030] A more complete understanding of the above and other features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0031] Figure 1 This is a schematic cross-sectional side view of the hydraulic unit of the submersible pump, i.e., the sewage pump, of the present invention, which includes the impeller seat and the open impeller of the present invention.

[0032] Figure 2 This is a schematic perspective view from above of the impeller housing according to the first embodiment of the present invention.

[0033] Figure 3 It is based on Figure 2 A schematic cross-sectional side view of the impeller seat.

[0034] Figure 4 This is a schematic perspective view of an open impeller from below.

[0035] Figure 5 It is based on Figure 4 A schematic cross-sectional side view of the impeller.

[0036] Figure 6 This is a schematic perspective view from above of the impeller housing according to the second embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram from above of a portion of the impeller seat according to the first embodiment.

[0038] Figure 8 According to the first embodiment ( Figure 7 A schematic diagram of a portion of the impeller housing from above.

[0039] Figure 9 It is based on the second embodiment ( Figure 6 A schematic diagram of a portion of the impeller housing from above.

[0040] Figure 10 It is based on Figure 7 A schematic diagram of a portion of the impeller seat from above, revealing the leading edge angle.

[0041] Figure 11 It is based on Figure 6 A schematic diagram of a portion of the impeller seat from above, revealing the leading edge angle.

[0042] Figure 12 It is based on Figure 2 A schematic cross-sectional side view of the impeller seat taken perpendicular to the leading edge of the guide pin.

[0043] Figure 13 It is based on Figure 12 Enlarged image of the guide pin.

[0044] Figure 14 It is based on Figure 7 A schematic diagram of a portion of the impeller seat from above reveals the upstream edge angle and the downstream edge angle of the slot inlet.

[0045] Figure 15 It is based on Figure 6 A schematic diagram of a portion of the impeller seat from above reveals the upstream edge angle and the downstream edge angle of the slot inlet.

[0046] Figure 16 It is based on Figure 7 A schematic diagram of the impeller seat viewed from above, and also disclosed according to... Figure 4 The protrusion of the free edge of the impeller blades, and

[0047] Figure 17 yes Figure 12 A partial diagram viewed from above, showing the scraping angle. Detailed Implementation

[0048] This invention specifically relates to the field of submersible pumps, particularly those configured for pumping liquids containing solid substances, such as sewage / wastewater pumps. Such pumps are configured to pump liquids such as sewage / wastewater, which may contain polymers, hygiene products, fabrics, rags, disposable gloves, face masks, etc. The invention particularly relates to impeller housings suitable for said pumps and applications.

[0049] Please refer to the following first. Figure 1 It discloses a schematic diagram of the hydraulic unit of a submersible pump, generally represented by 1. (Reference) Figure 1 This describes a common submersible pump, which is referred to as a pump in the following text.

[0050] 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 an impeller seat, generally indicated by 5, which surrounds the inlet 2. The volute 4 is also defined by an intermediate wall 6, which connects the volute 4 to the drive unit of pump 1 (from...). Figure 1 (Removed from the middle) Separate. The volute 4 is also referred to as the pump chamber, and the impeller seat 5 is also referred to as the suction cover, wear plate, or inlet insert. In some applications, the outlet of the hydraulic unit also constitutes the outlet 3 of the pump 1, while in other applications, the outlet of the hydraulic unit is connected to a separate outlet 3 of the pump 1. The outlet 3 of the pump 1 is configured to connect to an outlet conduit (not shown). Therefore, 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.

[0051] The drive unit of pump 1 includes: an electric motor disposed within a liquid-impermeable pump housing; and a drive shaft 8 extending from the electric motor through an intermediate wall 6 into a volute 4. During operation of pump 1, an impeller 7 is connected to and driven to rotate by the drive shaft 8, wherein, when pump 1 is running, liquid is drawn into the inlet 2 through the rotating impeller 7 and pumped out from the outlet 3. The pump housing, impeller seat 5, impeller 7, and other necessary 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-impermeable lead through-hole for receiving the electrical cable.

[0052] According to a preferred embodiment, pump 1 (more precisely, an electric motor) is operatively connected to a control unit, such as a smart drive including a variable frequency drive (VFD). Thus, via the control unit, pump 1 is configured to operate at a variable operating speed [rpm]. According to a preferred embodiment, the control unit is located within a liquid-impermeable pump housing; preferably, the control unit is integrated within 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 divided into external and internal sub-units. The operating speed of pump 1 is more precisely the rpm of the electric motor and impeller 7, and corresponds to / is related to the output frequency of the control unit. The control unit is configured and capable of operating pump 1 and impeller 7 in the normal direction of rotation (i.e., forward) to pump liquid, and in the opposite direction of rotation (i.e., backward) to clean or unclog pump 1 and impeller 7.

[0053] The components of pump 1 are typically cooled by the liquid / water surrounding pump 1. Pump 1 is designed and configured to operate in a submerged configuration / position, i.e., completely below the liquid surface during operation. However, it should be recognized that the 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, the submersible pump 1 includes a dedicated cooling system.

[0054] This invention is based on a new and improved impeller housing 5 configured for use in a pump 1 suitable for pumping liquids containing solids, such as wastewater / sewage containing substances that may temporarily clog or block the pump 1. When solids clog / block the pump 1, torque and power consumption increase. To prevent pressure on the pump 1, the control unit can initiate a cleaning procedure, during which the impeller 7 will rotate in reverse for a short period. If such reversing (one or several attempts) is insufficient, maintenance personnel need to go to the pump station to manually clean / repair the pump 1.

[0055] According to different embodiments, during the operation of pump 1, impeller 7 can move back and forth in the axial direction relative to impeller seat 5 so that larger pieces of solid material can pass through the volute 4 of pump 1.

[0056] Now for reference Figure 2 and Figure 3 The invention discloses an impeller seat 5 according to a first embodiment. Please refer to [reference needed] for some details. Figure 8 and Figure 9 .

[0057] Impeller seat 5 includes an axial inlet 9 defined by inlet wall 10, wherein impeller seat 5 has an inlet radius (R) measured from an axially extending central axis (A) to a circular intersection 11 between the inlet wall 10 and the upper surface 12 of impeller seat 5.

[0058] The inlet wall 10 is more or less cylindrical or slightly conical, in the downstream direction (i.e., in...). Figure 3 The upper surface 12 of the impeller seat 5 (viewed from above) has a reduced flow area. The circular intersection 11 is the plane of the impeller seat 5 with the minimum flow area, i.e., the transition between the inlet wall 10 and the upper surface 12. Therefore, the upper surface 12 is located downstream of the axial inlet 9. The upper surface 12 may include a flat section 12' and an arcuate section 12", wherein the flat section 12' may be located in a horizontal plane or inclined inward / downward, and the arcuate section 12" connects the flat section 12' and the inlet wall 10 to each other. According to different embodiments, the upper surface 12 only includes the arcuate section 12" extending from the inlet wall 10 to the periphery of the impeller seat 5. According to other different embodiments, the upper surface 12 only includes the flat section 12' extending from the inlet wall 10 to the periphery of the impeller seat 5.

[0059] The impeller seat 5 includes a guide pin 13 connected to and extending radially inward from the inlet wall 10, the guide pin 13 having an end radius (r) measured from the axially extending central axis (A) to the innermost radial portion of the guide pin 13. The primary function of the guide pin 13 is to scrape solid material from the impeller 7 and convey the solid material outward during normal operation of the pump 1.

[0060] According to different embodiments, the impeller seat 5 further includes a feed groove 14 disposed on the upper surface 12 of the impeller seat 5 and extending from the inlet wall 10 to the periphery of the impeller seat 5. Viewed from the rotation direction of the impeller 7, the inlet of the feed groove 14 is located near and upstream of the guide pin 13. Viewed from the inlet wall 10 toward the periphery, the feed groove 14 preferably sweeps along the rotation direction of the impeller 7. A portion of the inlet of the feed groove 14 may be disposed within the inlet wall 10 of the impeller seat 5. The function of the feed groove 14 is to convey solid material outward during normal operation of the pump 1.

[0061] Now for reference Figure 4 and Figure 5 The invention discloses an open impeller 7. The impeller 7 includes a cover plate 15, a centrally located hub 16, and at least two helical swept blades 17 connected to the cover plate 15 and the hub 16. The blades 17 are equidistantly located around the hub 16. The blades 17 are also referred to as impeller blades, and the cover plate 15 is also referred to as an upper shroud.

[0062] Viewed from the hub 16 toward the periphery of the impeller 7, the blades 17 sweep in a direction opposite to the direction of rotation of the impeller 7 during normal (liquid pumping) operation of the pump 1. Therefore, viewed from below (i.e.) Figure 4 During normal operation, the impeller 7 rotates counterclockwise.

[0063] Each blade 17 includes a leading edge 18 adjacent to the hub 16 and a trailing edge 19 located at the periphery of the impeller 7. The leading edge 18 of the impeller 7 is upstream of the trailing edge 19, wherein two adjacent blades 17 together define a passage extending from the leading edge 18 to the trailing edge 19. The leading edge 18 is located at the inlet of the impeller seat 5 and sweeps outward from the hub in a spiral pattern in the same direction as the sweeping of the blades 17. During operation, the leading edge 18 traps liquid, the passage accelerates the liquid and / or increases the pressure of the liquid, and the liquid exits the impeller 7 at the trailing edge 19. Thereafter, the liquid is guided towards the outlet 3 by the volute 4 of the hydraulic unit. Thus, liquid is drawn into the impeller 7 and expelled from the impeller 7. The passage is also defined by the cover plate 15 of the impeller 7 and the impeller seat 5 of the volute 4. The diameter of the impeller 7 and the shape and configuration of the passage / blades determine the pressure accumulation in the liquid and the pumped flow rate.

[0064] Each blade 17 also includes a lower edge 20, which extends from the leading edge 18 to the trailing edge 19 and separates the suction side / surface 21 of the blade 17 from the pressure side / surface 22 of the blade 17. The lower edge 20 is configured to face the impeller seat 5 of the pump 1 and is positioned opposite to the impeller seat 5 of the pump 1. Thus, the suction side 21 of one blade 17 is positioned opposite the pressure side 22 of the adjacent blade 17. The leading edge 18 and the trailing edge 19 also separate the suction side 21 and the pressure side 22. The leading edge 18 is preferably rounded. The lower edge 20 of the blade 17 is connected to the leading edge 18 at a position corresponding to the circular intersection 11 of the impeller seat 5.

[0065] Now for reference Figure 6-11 ,in Figure 6 , 9 Article 11 discloses an impeller seat 5 according to a second embodiment. Unless otherwise stated, the first and second embodiments are similar.

[0066] This invention is based on a new design, configuration, and function of the guide pin 13 and the feed groove 14. The design of the guide pin 13 and the feed groove 14 is defined by imaginary circles, wherein an imaginary 15% circle, represented by 23, is radially offset inward from the circular intersection 11 by 15 percent of the difference between the inlet radius (R) and the end radius (r), and wherein an imaginary 85% circle, represented by 24, is radially offset inward from the circular intersection 11 by 85 percent of the difference between the inlet radius (R) and the end radius (r). For this purpose, an imaginary 40% circle, represented by 25, is defined, which is radially offset inward from the circular intersection 11 by 40 percent of the difference between the inlet radius (R) and the end radius (r). The 15% and 85% circles are used because the impeller seat 5 includes a rounded transition between the guide pin 13 and the inner wall 10, and includes rounded ends; therefore, the shapes of the innermost and outermost portions of the guide pin 13 are not considered when defining the overall shape of the guide pin 13.

[0067] Guide pin 13 includes a leading edge 26 and a trailing edge 27, wherein see Figure 10 and 11 The leading edge line 29 is a straight line projected axially, extending between the intersection of the 15% circle 23 and the leading edge 26 of the guide pin 13 and the intersection of the 85% circle 24 and the leading edge 26 of the guide pin 13.

[0068] According to various embodiments, viewed from the direction of rotation and from the axial direction of the pump 1, at least between the inlet wall 10 and the 40% circle 25, the guide pin 13 includes a pre-leading edge 31 located upstream of the leading edge 26 of the guide pin 13. According to various embodiments, such as the first embodiment of the impeller seat 5, the pre-leading edge 31 is located upstream of the leading edge 26 at least between the inlet wall 10 and the 85% circle 24. Therefore, viewed from the direction of rotation of the impeller 7, at the upstream portion of the guide pin 13, the guide pin 13 includes a stepped configuration or a wedge-shaped recess configuration. Therefore, solid matter will be more easily scraped off the impeller 7, and in embodiments with an axially movable impeller 7, solid matter will more easily enter the gap between the guide pin 13 and the leading edge 18 of the blade 17, thereby moving the impeller 7. Therefore, the time required for solid matter to pass through is greatly reduced, i.e., scraping is more efficient and the scraping effect is more pronounced.

[0069] According to different embodiments, the leading edge angle (β) between the radius of the impeller seat 5 intersecting the leading edge 26 of the guide pin 13 at the 15% circle 23 and the leading edge line 29 is equal to or greater than 10 degrees and equal to or less than 30 degrees. Therefore, solid material at the leading edge 18 of the blade 17 is more easily scraped off.

[0070] According to different embodiments, the leading edge 26 of the guide pin 13 is mainly straight between the 15% circle 23 and the 40% circle 25.

[0071] According to various embodiments, at least a portion of the upper surface 30 of the guide pin 13 is a planar surface, defined by a 15% circle 23, an 85% circle 24, a leading edge 26, and a trailing edge 27. In this preferred context, the term planar surface means that any straight line connecting any two points on the surface lies entirely on said surface. According to various embodiments, the at least a portion of the upper surface 30 of the guide pin 13 is inclined relative to a horizontal plane, wherein, viewed in the axial direction, the distal end of the guide pin 13 is located upstream of the proximal end of the guide pin 13. From the proximal end of the guide pin 13 toward the distal end of the guide pin 13, the height of the guide pin 13 decreases, and the lower surface of the guide pin 13 is rounded to prevent solid matter from getting stuck on the underside of the guide pin 13. It is also feasible to bend / bend the upper surface 30 of the guide pin 13 upstream or downstream to follow the corresponding shape of the leading edge of the blade 17 of the impeller 7, wherein the upper surface 30 remains a planar surface. The leading edge 18 of the blade 17 is preferably located in a horizontal plane or a conical surface, wherein the inner portion of the leading edge moves in the upstream direction.

[0072] The distance (i.e., clearance height) between the leading edge 18 of the blade 17 and the upper surface 30 of the guide pin 13 is equal to or greater than 0.05 mm and equal to or less than 1 mm, preferably equal to or greater than 0.1 mm and equal to or less than 0.5 mm. This also applies to the distance between the upper surface 12 of the impeller seat 5 and the lower edge 20 of the blade 17.

[0073] Still referencing Figure 12 and 13 According to different embodiments, the axial distance between the leading edge 31 and the leading edge 26 of the guide pin 13 is greater than 1 mm and equal to or less than 4 mm. If the axial distance is too small, solid material will not enter the gap; if the axial distance is too large, the movement effect of the impeller 7 in the axial direction will be reduced.

[0074] Leading edge 31 and leading edge 26 are connected via intermediate surface 32, which may be curved, planar, or a combination thereof. The angle of drop (η) between the upper surface 30 of the guide pin 13, which is perpendicular to and cuts off at leading edge 26, and intermediate surface 32 is equal to or greater than 90 degrees and equal to or less than 120 degrees. An angle of drop that is too small will cut solid material into smaller fragments, which is undesirable, while an angle of drop that is too large will reduce or eliminate the scraping effect of leading edge 26.

[0075] According to different embodiments, when viewed in the direction of rotation of pump 1 / impeller 7, at least between inlet wall 10 and imaginary 40% circle 25, the leading edge 26 is located downstream of the pre-leading edge 31 at least 20 percent of the distance between the pre-leading edge 31 and the trailing edge 27, which is perpendicular to the leading edge 26.

[0076] Viewed from the direction of rotation of pump 1, the downstream edge 33 of feed groove 14 connects to the leading edge 26 of guide pin 13 at the inlet of feed groove 14. Intermediate surface 32 connects to the surface of feed groove 14, i.e., feed groove begins in guide pin 13.

[0077] There are differences between the first embodiment and the second embodiment of the impeller seat 5. In the first embodiment, the guide pin 13 is at an angle relative to the radius of the impeller seat 5; in the second embodiment, the distal end of the guide pin 13 points towards the center of the impeller seat 5. Therefore, according to the first embodiment of the impeller seat 5, from the rotation direction of the impeller 7 (in... Figure 6-11 Looking at the center (clockwise), the distal end of the guide pin 13 is located upstream of the proximal end of the guide pin 13.

[0078] Now for reference Figure 14 and 15This further defines the design and coordination of the guide pin 13 and the feed groove 14. The new design is defined by the upstream edge line 34 and the downstream edge line 36 of the groove inlet. Viewed in the rotational direction of the pump 1, the upstream edge line is the radius at which the impeller seat 5 intersects the upstream edge 35 of the feed groove 14 at the circular intersection 11, and the downstream edge line is the radius at which the impeller seat 5 intersects the downstream edge 33 of the feed groove 14 at the circular intersection 11. It should be noted that, viewed from the rotational direction of the pump 1, i.e., from the rotational direction of the impeller 7, the upstream edge of the guide pin 13 is formed by the leading edge 26 and / or the pre-leading edge 31, with the most upstream being considered.

[0079] Importantly, viewed in the direction of pump 1's rotation, the angle (λ) between the radius of the impeller seat 5 at the 15% circle 23 where it intersects with the upstream edge of the guide pin 13 and the upstream edge line 34 of the groove inlet is equal to or less than 20 degrees and equal to or greater than 0 degrees. Therefore, the inlet of the feed groove 14 is smaller, significantly reducing or eliminating backflow into the inlet of the impeller seat 5. Thus, viewed in the direction of pump 1's rotation, the upstream edge line 34 of the groove inlet at the circular intersection 11 is located upstream of or coincides with the radius of the impeller seat 5 at the 15% circle 23 where it intersects with the upstream edge of the guide pin 13.

[0080] According to different embodiments, when viewed from the rotation direction of pump 1, the upstream point of the upstream edge 35 of feed trough 14 is located at the upstream edge line 34 of trough inlet.

[0081] According to different embodiments, viewed in the rotation direction of pump 1, the angle (τ) between the radius of the impeller seat 5 intersecting the upstream edge of the guide pin at the 15% circle 23 and the downstream edge line 36 of the groove inlet is equal to or greater than 15 degrees and equal to or less than 30 degrees. Therefore, most of the backflow is directed to the intermediate surface 31 of the guide pin 13.

[0082] Now for reference Figure 16 and 17 The free edge of the blade 17 of the impeller 7 and the hub 16 of the impeller 7 are projected onto the impeller seat 5. More specifically, the illustration shows the combined action between the leading edge 18 of the blade 17 and the guide pin 13.

[0083] According to different embodiments, the innermost radial portion of the guide pin 13 is located radially outside the hub 16 of the impeller 7. Therefore, solid material may not be trapped between the hub 16 of the impeller 7 and the upper surface 30 of the guide pin 13, and solid material raked off during the reverse operation of the pump 1 will more easily leave the guide pin 13.

[0084] According to various embodiments, the scraping angle (δ) between the projected tangent of the leading edge 26 of the guide pin 13 and the projected tangent of the intersection between the leading edge 18 of the blade 17 and the pressure side 22 of the blade 17 is greater than 90 degrees and equal to or less than 120 degrees, and wherein the leading edge 18 of the blade 17 spirally sweeps from the hub 16 of the impeller 7 to the lower edge 20 of the blade 17. Therefore, it will be easier to scrape any solid material from the impeller 7.

[0085] Feasible modifications to the present invention

[0086] 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.

[0087] It should also be noted that all information regarding / related terms, such as upper, lower, top, bottom, etc., should be interpreted / read according to the orientation of the device in the figures, and the orientation of the figures should be adjusted to a level that allows for correct reading. Therefore, these terms only indicate the interrelationships in the illustrated embodiments, and these relationships may be changed if the device of the present invention has another structure / design.

[0088] It should also be noted that even if it is not explicitly stated that a feature of a particular embodiment can be combined with a feature of another embodiment, such combination should be considered obvious if it is possible.

Claims

1. An impeller seat (5) for a pump (1), the pump being configured to pump a liquid containing a solid substance, the impeller seat (5) having an axial inlet (9) defined by an inlet wall (10) and an upper surface (12) located downstream of the axial inlet (9), wherein the impeller seat (5) has an inlet radius (R) measured from an axially extending central axis (A) to a circular intersection (11) between the inlet wall (10) and the upper surface (12) of the impeller seat (5), the impeller seat (5) including connections to and from the inlet wall (10). A guide pin (13) extending radially inward has an end radius (r) measured from the axially extending central axis (A) to the innermost radial portion of the guide pin (13), wherein an imaginary 15% circle (23) is radially offset from the intersection of the circles (11) by fifteen percent of the difference between the inlet radius (R) and the end radius (r). The impeller seat (5) includes a feed groove (14) arranged in the upper surface (12) of the impeller seat (5) and extending from the inlet wall (10) to the periphery of the impeller seat (5). Its features are, Viewed from the direction of rotation of the pump (1), the upstream edge line (34) of the slot inlet is the radius at which the impeller seat (5) intersects the upstream edge (35) of the feed slot (14) at the circular intersection (11), wherein the upstream edge angle (λ) of the slot inlet between the radius at which the impeller seat (5) intersects the upstream edge of the guide pin (13) at the 15% circle (23) as viewed from the direction of rotation of the pump (1) and the upstream edge line (34) of the slot inlet is equal to or less than 20 degrees and equal to or greater than 0 degrees, wherein the upstream edge line (34) of the slot inlet at the circular intersection (11) is located upstream of the radius at which the impeller seat (5) intersects the upstream edge of the guide pin (13) at the 15% circle (23) as viewed from the direction of rotation of the pump (1), or coincides with the radius at which the impeller seat intersects the upstream edge of the guide pin at the 15% circle as viewed from the direction of rotation of the pump.

2. The impeller seat (5) according to claim 1, wherein, viewed from the direction of rotation of the pump (1), the downstream edge line (36) of the slot inlet is the radius of the impeller seat (5) at the intersection of the circles (11) with the downstream edge (33) of the feed slot (14), wherein the downstream edge angle (τ) of the slot inlet between the radius of the impeller seat (5) at the 15% circle (23) with the upstream edge of the guide pin (13) and the downstream edge line (36) of the slot inlet is equal to or greater than 15 degrees and equal to or less than 30 degrees.

3. The impeller seat (5) according to claim 1 or 2, wherein the upstream point of the upstream edge (35) of the feed groove (14) as viewed from the rotation direction of the pump (1) is located at the upstream edge line (34) of the groove inlet.

4. The impeller seat (5) according to claim 1 or 2, wherein the feed groove (14) sweeps from the inlet wall (10) to the periphery of the impeller seat (5) along the rotation direction of the pump (1).

5. The impeller seat (5) according to claim 1 or 2, wherein the imaginary 40% circle (25) is radially offset inward from the intersection of the circles (11) by forty percent of the difference between the inlet radius (R) and the end radius (r), wherein the guide pin (13) includes a leading edge (26) configured to scrape contaminants from the impeller of the pump (1), wherein, viewed from the direction of rotation of the pump (1) and from the axial direction, at least between the inlet wall (10) and the 40% circle (25), the guide pin (13) includes a pre-leading edge (31) located upstream of the leading edge (26) of the guide pin (13).

6. The impeller seat (5) according to claim 5, wherein, viewed from the direction of rotation of the pump (1), the downstream edge (33) of the feed groove (14) is connected to the leading edge (26) of the guide pin (13).

7. The impeller seat (5) according to claim 5, wherein the axial distance between the pre-leading edge (31) and the leading edge (26) of the guide pin (13) is greater than 1 mm and equal to or less than 4 mm.

8. The impeller seat (5) according to claim 1 or 2, wherein the imaginary 85% circle (24) is radially offset inward from the intersection of the circles by eighty-five percent of the difference between the inlet radius (R) and the end radius (r), and wherein the leading edge line (29) is a projected straight line extending between the intersection between the leading edge (26) of the 15% circle (23) and the guide pin (13) and the intersection between the 85% circle (24) and the leading edge (26), and wherein the leading edge angle (β) between the radius of the impeller seat (5) intersecting the leading edge (26) at the 15% circle (23) and the leading edge line (29) is equal to or greater than 10 degrees and equal to or less than 30 degrees.

9. The impeller seat (5) according to claim 1 or 2, wherein at least a portion of the upper surface of the guide pin (13) is a planar surface, said at least a portion being defined by a 15% circle (23), an 85% circle (24), a leading edge (26) and a trailing edge (27).

10. The impeller seat (5) according to claim 9, wherein at least a portion of the upper surface of the guide pin (13) is inclined relative to the horizontal plane, wherein, viewed in the axial direction, the distal end of the guide pin (13) is located upstream of the proximal end of the guide pin (13).

11. A pump (1) for pumping a liquid containing a solid substance, the pump (1) comprising an open impeller (7) having a cover plate (15), a centrally located hub (16), and at least two spirally swept blades (17) connected to the cover plate (15) and the hub (16), wherein each blade (17) of the impeller (7) includes a leading edge adjacent to the hub (16), a trailing edge located at the periphery of the impeller (7), and a lower edge (20), wherein the lower edge (20) extends from the leading edge to the trailing edge and separates the suction side (21) of the blade (17) from the pressure side (22) of the blade (17), characterized in that, The pump (1) further includes an impeller seat (5) according to any one of claims 1-10, wherein the leading edge of the blade (17) is configured to cooperate with the guide pin (13) of the impeller seat (5) during operation of the pump (1), and wherein the lower edge (20) of the blade (17) is positioned opposite the upper surface (12) of the impeller seat (5).

12. The pump (1) according to claim 11, wherein during operation of the pump (1), the impeller (7) is capable of moving back and forth relative to the impeller seat (5) in the axial direction.

13. The pump (1) according to claim 11 or 12, wherein the scraping angle (δ) between the projected tangent of the leading edge (26) of the guide pin (13) and the projected tangent of the intersection between the leading edge of the blade (17) and the pressure side (22) of the blade (17) is greater than 90 degrees and equal to or less than 120 degrees, and wherein the leading edge of the blade (17) is spirally swept from the hub (16) to the lower edge (20) of the blade (17).

14. The pump (1) according to claim 11 or 12, wherein the innermost radial portion of the guide pin (13) is located radially outside the hub (16) of the impeller (7).

15. The pump (1) according to claim 11 or 12, wherein the gap between the leading edge of the blade (17) of the impeller (7) and the upper surface of the guide pin (13) is equal to or greater than 0.05 mm and equal to or less than 1 mm.

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