Impeller and pumping system

Abstract

To provide an impeller and pump device that can suppress leakage in mice. [Solution] An impeller 30 used in a water pump 12 having a liner ring 22e comprises a disc-shaped back shroud 31, a plurality of blades 33 arranged along the circumferential direction of the back shroud 31 and fixed to the back shroud 31, and a front shroud 32 which is positioned opposite the back shroud 31 and fixed to the plurality of blades 33, with an inlet 32b formed therein whose inner circumferential surface gradually narrows in diameter from the tip toward the blades 33, and the end of the inlet 32b facing the liner ring 22e in the axial direction.

Description

Technical Field

[0001] The present invention relates to an impeller and a pump device.

Background Art

[0002] Conventionally, a pump that pumps fluid to the secondary side by rotating an impeller has been known (see, for example, Patent Document 1). The mouth of the impeller used in such a pump suppresses leakage of water passing through the impeller by facing or contacting the lining on the outer peripheral surface (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The pump device increases the pressure of the water sucked in by the mouse and discharges it by rotating the impeller. For this reason, the pressure on the outer peripheral surface side of the mouse becomes higher than the pressure on the inner peripheral surface side due to the water discharged from the impeller. Due to the pressure difference generated in this mouse, the mouse is pressed toward the rotation center side of the impeller, so that the mouse deforms in the direction of separating from the lining, a gap is generated between the mouse and the lining, and the water discharged to the secondary side returns to the primary side, resulting in the possibility that necessary pump characteristics such as discharge amount, head, and efficiency cannot be exhibited.

[0005] Therefore, an object of the present invention is to provide an impeller and a pump device capable of suppressing leakage in a mouse.

Means for Solving the Problems

[0006] According to one aspect of the present invention, the impeller is a water pump having a liner ring and comprises a disc-shaped back shroud, a plurality of blades arranged along the circumferential direction of the back shroud and fixed to the back shroud, and a front shroud having a suction port that gradually decreases in diameter from the tip toward the blades, with the end of the suction port facing the liner ring in the axial direction, and positioned opposite the back shroud and fixed to the plurality of blades, and a plurality of blades arranged along the circumferential direction of the back shroud and fixed to the back shroud, and a front shroud having a suction port that gradually decreases in diameter from the tip toward the blades, with the end face of the suction port facing the liner ring in the axial direction, and positioned opposite the back shroud and fixed to the plurality of blades. [Effects of the Invention]

[0007] The present invention can provide an impeller and pump device that can suppress leakage in mice. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view showing the configuration of a pump using an impeller according to one embodiment of the present invention. [Figure 2] A cross-sectional view showing an enlarged view of the pump's components. [Figure 3] A plan view showing the configuration of the impeller. [Modes for carrying out the invention]

[0009] Hereinafter, an impeller 30 and a pump device 1 using the impeller 30 according to one embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a side view showing a partial cross-section of the configuration of the pump device 1 according to one embodiment of the present invention, Figure 2 is an enlarged cross-sectional view showing the configuration of the pump casing 22 and impeller 30 of the pump device 1, and Figure 3 is a plan view showing the configuration of the impeller 30. For explanatory purposes, some configurations in each figure have been omitted or enlarged or reduced as appropriate.

[0010] The pump device 1 is either a single-stage pump or a multi-stage pump. In this embodiment, as shown in Figure 1, the pump device 1 will be described using the example of a two-stage pump having two impellers 30, which will be described later, as a multi-stage pump. The pump device 1 comprises a motor 11 and a pump 12 that pumps water. For example, the pump device 1 is connected to a control panel that houses an inverter and multiple control boards. The pump device 1 also comprises a base 13 that supports the motor 11 and the pump 12.

[0011] Motor 11 is connected to pump 12 and drives pump 12. Motor 11 is connected to a control panel by a cable. Motor 11 is connected to a control board via multiple inverters, and its rotational speed is controlled by a control unit mounted on the control board.

[0012] As shown in Figure 1, the pump 12 comprises a rotating shaft 21, a pump casing 22, a casing cover 23, and one or more impellers 30 housed in the pump casing 22 and fixed to the rotating shaft 21.

[0013] The rotating shaft 21 is connected to the motor 11. The rotating shaft 21 may be connected to the motor shaft of the motor 11 via a shaft coupling, or it may be fixed to the rotor of the motor 11 and serve as the motor shaft as well. The rotating shaft 21 is configured to be able to fix the impeller 30 of the pump 12. The rotating shaft 21 is supported by a bearing member.

[0014] The pump casing 22 houses a plurality of impellers 30. The pump casing 22 includes, for example, a suction section 22a, a housing section 22b provided continuously with the suction section 22a, and a cylindrical discharge section 22c provided on a part of the outer surface of the pump casing 22, for example, on the upper part of the pump casing 22, communicating with the outer circumference of the housing section 22b. The pump casing 22 also has, for example, a plurality of inner casings 22d provided in the housing section 22b, which house each impeller 30. The motor 11 side of the pump casing 22 is open so that the inner casings 22d and the impellers 30 can be placed inside the housing section 22b.

[0015] The inner diameter of the suction section 22a expands from the tip side toward the housing section 22b side. The housing section 22b is formed to accommodate, for example, multiple inner casings 22d, and to allow fluidic continuity between the flow path within the inner casing 22d and the discharge section 22c. The inner casing 22d is also provided with a liner ring 22e facing the suction port 32b, which is the mouth of the impeller 30 housed inside.

[0016] The inner casing 22d has, for example, a guide vane 22f composed of multiple guide blades that guide water discharged from the outer edge of the impeller 30 to a suction port 32b located in the center of the secondary impeller 30. The guide vane 22f straightens the water discharged from the outer edge of the primary impeller 30 in the direction of water flow and directs the water from the discharge section 22f1 to the suction port 32b located in the center of the secondary impeller 30.

[0017] As shown in FIGS. 1 and 2, the lining 22e is provided at the end on the suction portion 22a side of the accommodation portion 22b of the inner casing 22d. As shown in FIG. 2, the end face 22e1 on the impeller 30 side of the lining pheric axial direction along the the center of the central axis of the rotation shaft 21, in other words, in the axial direction that becomes the rotation center, faces the end face 32b1 of the suction port 32b of the impeller 30 described later. The inner diameter of the lining 22e is formed to be the same as or slightly larger than the diameter on the accommodation portion 22b side of the suction portion 22a. The cross-section of the lining 22e is a rectangular shape composed of an end face 22e1, an inner peripheral surface orthogonal to the end face 22e1, and an outer peripheral surface orthogonal to the end face 22e1. The lining 22e of the present embodiment is made of, for example, copper.

[0018] The casing cover 23 is fixed to the pump casing 22 and the motor casing 11a of the motor 11. The casing cover 23 closes the opening on the motor 11 side of the pump casing 22.

[0019] As shown in FIGS. 1 to 3, the impeller 30 is a closed-type impeller. The impeller 30 is, for example, a press impeller formed of a metal material such as stainless steel. As shown in FIGS. 1 to 3, the impeller 30 includes a back shroud 31, a front shroud 32 disposed opposite to the back shroud 31, a plurality of blades 33 disposed at equal intervals in the circumferential direction of the impeller 30 and disposed between the back shroud 31 and the front shroud 32, and an impeller hub 34 provided at the center of the back shroud 31.

[0020] The back shroud 31 is configured in a disc shape. The back shroud 31 extends in a direction orthogonal or skew to the axis that is the rotation center of the impeller 30, and is formed in an annular plate shape with an opening 31a formed at the center.

[0021] The front shroud 32 is disposed to face the rear shroud 31 with a predetermined gap therebetween. The outer shape of the front shroud32 in a plan view seen in the axial direction is formed in a circular shape. The front shroud 32 is integrally formed with a fixing portion 32a for fixing a plurality of blades 33 and a cylindrical suction port 32b that forms a circular opening for sucking fluid into the center and whose diameter gradually decreases from the tip side. In the following description, the portion where the fixing portion 32a and the suction port 32b are continuous will be described as a continuous portion 32c.

[0022] For example, the front shroud 32 is orthogonal to the central axis of the impeller 30 or at least part of it extends in a direction intersecting the central axis of the impeller 30 such that the gap in the axial direction between the impeller 30 and the rear shroud 31 is constant or gradually increases from the outer peripheral edge side toward the center side.

[0023] The fixing portion 32a is formed in a disk shape with the continuous portion 32c and the suction port 32b continuous at the center. The central side of the fixing portion 32a is open, and the suction port 32b is provided via the continuous portion 32c. A plurality of blades 33 are fixed to the main surface (inner surface) of the fixing portion 32a facing the rear shroud 31, or a plurality of blades 33 are integrally formed. The fixing portion 32a extends in a direction orthogonal to the rotation axis of the impeller 30, or is inclined with respect to the rotation axis of the impeller 30 in a direction away from the rear shroud 31 as a whole or at least on the central side in the radial direction.

[0024] In the present embodiment, as shown in FIG. 2, the fixing portion 32a, for example, extends in a direction orthogonal to the rotation axis of the impeller 30 on the outer side in the radial direction, that is, the outer peripheral edge side, and extends in a direction inclined with respect to the rotation axis of the impeller 30 in a direction away from the rear shroud 31 on the central side in the radial direction, that is, the continuous portion 32c side. When the fixing portion 32a is configured to be inclined, it may be inclined linearly or may be inclined in a curved surface shape. That is, the fixing portion 32a is inclined in a shape along the inclined shape of the blades 33 fixed opposite thereto.

[0025] As shown in Figure 2, the intake port 32b is the mouth of the impeller 30. The end face 32b1 of the intake port 32b either faces the liner ring 22e with a predetermined gap or is in contact with the liner ring 22e. The end face 32b1 extends along a direction perpendicular to the axial direction of the impeller 30 and is formed in an annular shape.

[0026] The inner diameter of the inner surface of the suction port 32b is larger at the tip side of the suction port 32b than at the back shroud 31 side in the axial direction of the impeller 30, and gradually decreases in diameter from the tip side toward the back shroud 31 side.

[0027] More specifically, the inner circumferential shape of the suction port 32b is a so-called bell mouth shape. The inner circumferential shape of the suction port 32b tapers and / or curves in diameter from the tip of the suction port 32b toward the back shroud 31 (multiple blades 33) to a position in the axial direction of the impeller 30 that is to the tip surface of the boss portion 34b of the impeller hub 34 (described later), or to a position that is to the tip of the blades 33. As a specific example, the inner circumferential shape of the suction port 32b is formed as a tapered surface from the tip of the suction port 32b toward the back shroud 31 (multiple blades 33) to a position in the axial direction of the impeller 30 that is to the tip surface of the boss portion 34b of the impeller hub 34, and is continuous with the continuous portion 32c. In this context, the tip of the blade 33 in the axial direction of the impeller 30 refers to the highest point of the blade 33 on the central side of the impeller 30, relative to the back shroud 31.

[0028] The inner circumferential surface of the suction port 32b is positioned on the primary side of the flow path within the impeller 30 in the direction of water flow. The outer circumferential surface of the suction port 32b is exposed within the inner casing 22d and, as a result, is positioned on the secondary side of the impeller 30. Therefore, when the impeller 30 rotates and increases the water pressure, the pressure on the inner circumferential surface of the suction port 32b is lower than that on the outer circumferential surface.

[0029] The continuous section 32c is the part that connects the fixed section 32a and the suction port 32b, and is formed by a part of the fixed section 32a and a part of the suction port 32b. Therefore, the outer circumferential surface of the continuous section 32c is exposed and positioned inside the inner casing 22d, and as a result, in the direction of water flow, the inner circumferential surface side of the continuous section 32c is the primary side, and the outer circumferential surface side of the continuous section 32c is the secondary side. The inner circumferential surface of the continuous section 32c is curved and continuous with the inner surface of the fixed section 32a and the inner circumferential surface of the suction port 32b. The continuous section 32c gradually decreases in diameter from the inner circumferential end side of the fixed section 32a toward the center in the axial direction, and at the center in the axial direction it becomes the top, i.e., the minimum inner diameter of the outer shroud 32, and then gradually increases in diameter from the center toward the suction port 32b, and continues toward the suction port 32b. For example, the part of the continuous section 32c that is on the blade side of the top where it has the smallest inner diameter forms part of the fixed section 32a, and the part of the continuous section 32c that is on the opposite side of the blade 33 from the top where it has the smallest inner diameter forms part of the intake port 32b.

[0030] The inner circumferential surface of the continuous section 32c is formed in a curved shape that protrudes radially inward. The central part of the continuous section 32c, which has the smallest diameter, is located on the back shroud 31 side of the tip surface of the boss section 34b in the axial direction of the impeller 30, and is at the same position as the tip of the blade 33, or on the back shroud 31 side of the tip of the blade 33. Furthermore, the continuous section 32c is positioned radially towards the center from the end surface 32b1 of the suction port 32b.

[0031] Furthermore, the central portion of the continuous section 32c, which has the smallest diameter, is located radially closer to the center than the inner diameter of the end face of the housing section 22b, and outside the inner diameter of the primary side of the suction section 22a. In other words, the minimum diameter of the continuous section 32c is smaller than the inner diameter of the end face of the housing section 22b, and larger than the inner diameter of the tip, which is the primary side of the suction section 22a. Also, the central portion of the continuous section 32c is located radially closer to the center than the inner circumferential surface of the secondary side of the suction section 22a and the inner circumferential surface of the liner ring 22e. In other words, the minimum diameter of the continuous section 32c is formed to be smaller than the inner diameter of the secondary side of the suction section 22a on the housing section 22b side, and the inner diameter of the liner ring 22e. For example, the continuous section 32c faces radially from the portion of the inner wall of the inner casing 22d that is axially on the suction section 22a side of the portion where an opening is formed through which water discharged from the impeller 30 flows to the secondary side, via a space filled with water in the radial direction.

[0032] The outer circumferential surface of the continuous section 32c has a concave shape that is recessed perpendicular to the rotation axis 21 and away from the inner wall of the inner casing 22d, forming an annular groove on the outer circumferential surface of the mouth of the impeller 30. In other words, the outer circumferential surface of the continuous section 32c is recessed radially inward. The shape of the outer circumferential surface of the continuous section 32c is, for example, recessed in an arc shape in cross-section. The annular groove formed on the outer circumferential surface of the continuous section 32c is recessed radially on the side of the inner diameter of the liner ring 22e that is smaller in diameter. The inner diameter of the inner circumferential surface of the continuous section 32c that radially corresponds to the outer circumferential surface recessed on the innermost side of the annular groove of the continuous section 32c is the minimum inner diameter of the surface shroud 32. A portion of the water discharged from the impeller 30 to the secondary side fills the space created between the outer circumferential surface of the continuous section 32c and the inner wall of the inner casing 22d.

[0033] Figure 2 illustrates a specific example of the shape and positional relationship between the table shroud 32 and the liner ring 22e. The end of the suction port 32b faces the liner ring 22e in the axial direction along the rotation center of the impeller 30. Furthermore, the end face 32b1 of the suction port 32b approaches, contacts, or is in close contact with the liner ring 22e, at least when the water is pressurized by the impeller 30. For example, when the impeller 30 is not rotating, the end face 32b1 of the suction port 32b approaches or contacts the end face 22e1 of the liner ring 22e that faces the suction port 32b, with a predetermined gap between them. That is, when the impeller 30 is rotating, pressure is applied to the end of the suction port 32b in a direction that approaches the liner ring 22e, causing it to deform.

[0034] Here, the predetermined gap between the end face 32b1 of the suction port 32b and the end face 22e1 of the liner ring 22e is such that when the impeller 30 rotates and the water is pressurized and discharged by the impeller 30, the pressure on the outer surface side of the suction port 32b becomes higher than the pressure on the inner surface of the suction port 32b, and the gap allows the suction port 32b to deform radially inward up to the end face 22e1 of the liner ring 22e. Considering that water leaks from the gap between the end face 32b1 of the suction port 32b and the end face 22e1 of the liner ring 22e when the impeller 30 starts to rotate, it is preferable that the end face 32b1 of the suction port 32b is close to the end face 22e1 of the liner ring 22e that faces the suction port 32b when the impeller 30 is not rotating.

[0035] Furthermore, the portion of the outer shroud 32 with the smallest inner diameter is located radially closer to the center than the opening end of the suction port 32b and the inner circumferential surface of the liner ring 22e. Specifically, when the inner diameter of the liner ring 22e is Φ1, the inner diameter at the end face 32b1 of the suction port 32b of the outer shroud 32 is Φ2, and the smallest diameter at the continuous portion 32c is Φ3, then Φ3 < Φ1 ≤ Φ2. This is because if the inner diameter Φ1 of the liner ring 22e becomes less than or equal to the smallest diameter Φ3 of the continuous portion 32c, the water straightening function produced by the bell mouth shape of the suction port 32b will be reduced. Furthermore, if the inner diameter Φ1 of the liner ring 22e is larger than the inner diameter Φ2 of the suction port 32b, the area where the end face 22e1 of the liner ring 22e and the end face 32b1 of the suction port 32b face each other becomes smaller than the maximum area, which reduces the sealing performance and may cause the deformed suction port 32b to detach from the liner ring 22e.

[0036] Multiple blades 33 are provided between the back shroud 31 and the front shroud 32, arranged at equal intervals in the circumferential direction of the impeller 30. For example, among the multiple blades 33, adjacent blades 33 in the circumferential direction are spaced apart at the radially outer end of one blade 33 on the impeller 30 and at the radially central end (i.e., the end on the intake port 32b side) of the other blade 33 on the impeller 30, while overlapping in the radial direction.

[0037] The blades 33 are joined to the back shroud 31 and the front shroud 32, for example, by laser welding or the like. The blades 33 are curved, for example, with a predetermined radius of curvature. The axial ends of the blades 33 on the impeller 30 extend in the same direction as the fixed back shroud 31 and front shroud 32. Specifically, the end face of the blade 33 on the back shroud 31 side extends along a direction perpendicular to the axial direction. The end face of the blade 33 on the front shroud 32 side extends, for example, radially outward along a direction perpendicular to the axial direction, and is inclined with respect to the axial direction so as to move away from the back shroud 31 toward the radial center. Furthermore, the end face 33a of the blade 33, which is located on the central side of the impeller 30, is inclined with respect to the axial direction so as to move away from the center of the impeller 30 toward the front shroud 32 side from the back shroud 31 side. Furthermore, the apex 33b of the inclined end face 33a of the blade 33, that is, the apex 33b on the opposite side from the back shroud 31, is the highest point relative to the back shroud 31.

[0038] The blades 33 are arranged to extend from the back shroud 31 toward the front shroud 32, and at least the end on the central side of the impeller 30 is inclined with respect to the axial direction. For example, as shown in Figures 2 and 3, the end of the blade 33 on the side of the end face 33a that is inclined with respect to the axial direction has one circumferential side surface 33c inclined with respect to the axial direction, so that one circumferential side surface 33c of the blade 33 faces the opening of the suction port 32b in the axial direction. In other words, in the axial direction of the impeller 30, one side surface 33c of the blade 33 is visible from the opening of the suction port 32b and becomes the contact surface for water sucked in from the suction port 32b.

[0039] The blade 33 is positioned at the central end of the impeller 30, specifically the end including the end face 33a, which is located inside the inner circumferential surface of the suction port 32b and the continuous portion 32c. That is, the end of the blade 33, including the end face 33a, is positioned within the opening of the suction port 32b of the front shroud 32.

[0040] The spacing between adjacent blades 33 in the circumferential direction of the impeller 30 gradually increases from the center of the impeller 30 toward the outer edge. The height of the blades 33 from the back shroud 31 toward the front shroud 32 is higher on the center side of the impeller 30 than on the outer surface side.

[0041] A specific example of the shape and positional relationship between the table shroud 32 and the blade 33 will be explained.

[0042] With respect to the central axis (center of rotation) of the impeller 30, the inclination angle of the inner circumferential surface of the intake port 32b of the front shroud 32 is formed to be the same as, or approximately the same as, the inclination angle of the end face 33a of the blade 33 that is on the central side of the impeller 30. In other words, the extending direction of the end face 33a of the blade 33 is along the inclination direction of the inner circumferential surface of the intake port 32b, or extends in approximately the same direction. For example, at least a portion of the end face 33a of the blade 33 is arranged on the same plane or approximately on the same plane as the inner circumferential surface of the intake port 32b. In other words, the inner circumferential surface of the intake port 32b of the front shroud 32 and the end face 33a of the blade 33 are arranged on the same virtual plane, for example, and are formed to be continuous on this virtual plane.

[0043] The impeller hub 34 is formed in a cylindrical shape with partially different outer diameters and is located at the center of the back shroud 31. The impeller hub 34 is joined to the back shroud 31 by welding, such as laser welding. The impeller hub 34 includes, for example, a seat portion 34a that abuts against the back shroud 31 when inserted into the opening 31a of the back shroud 31, a cylindrical boss portion 34b that protrudes from the back shroud 31 towards the intake port 32b of the front shroud 32, and a hole portion 34c formed across the seat portion 34a and the boss portion 34b for inserting the rotating shaft 21. The impeller hub 34 is inserted into the opening 31a of the back shroud 31 and joined to the back shroud 31 with the seat portion 34a in contact with the back shroud 31. The boss portion 34b is formed in a cylindrical shape, for example, with its outer diameter decreasing from the back shroud 31 towards the front shroud 32, and becoming constant at the tip.

[0044] Such an impeller 30 is formed by press-forming a metal plate such as a steel plate to create a back shroud 31 which will be the main plate, a front shroud 32 which will be the side plate, and a plurality of blades 33, and then integrally joining the formed back shroud 31, front shroud 32 and plurality of blades 33 by laser welding or the like. The impeller hub 34 may be joined at the same time as the joining of the back shroud 31, front shroud 32 and plurality of blades 33, or after the joining of the back shroud 31, front shroud 32 and plurality of blades 33, or it may be joined to the back shroud 31 in advance before joining the back shroud 31, front shroud 32 and plurality of blades 33. In addition, the intake port 32b of the front shroud 32 is formed, for example, by expanding its diameter with a processing tool such as a spatula after press-forming.

[0045] In the pump device 1 configured in this way, the impeller 30 has a bell-mouth shaped suction port 32b that faces the liner ring 22e in the axial direction along the rotation center of the impeller 30. As a result, when the impeller 30 rotates, the suction port 32b approaches or contacts the liner ring 22e. This prevents gaps from forming between the impeller 30 and the liner ring 22e, thus preventing leakage between the impeller 30 and the liner ring 22e, and thus improving pump performance.

[0046] To explain in more detail, when the impeller 30 increases the pressure of the water, the pressurized water moves to the outer surface side of the suction port 32b of the impeller 30. As a result, the pressure on the outer surface side of the suction port 32b (the secondary side of the impeller 30) becomes higher than the pressure on the inner surface side of the suction port 32b (the primary side of the impeller 30). Due to this pressure difference between the inner and outer surfaces of the suction port 32b, pressure is applied to the suction port 32b in such a way that it deforms radially inward. As a result, the suction port 32b deforms from an inclined state to a direction parallel to the central axis of the impeller 30. Therefore, the pressure on the outer circumferential surface of the suction port 32b applies a force that presses the end face 32b1 of the suction port 32b toward the end face 22e1 of the liner ring 22e. As a result, the end face 32b1 of the suction port 32b approaches the central axis of the impeller 30 and comes into close proximity to or contact with the end face 22e1 of the liner ring 22e in the axial direction.

[0047] As the pressure on the outer surface side of the suction port 32b of the impeller 30 increases, it approaches or comes into contact with the end face 22e1 of the liner ring 22e, thereby reducing the gap between the liner ring 22e and the suction port 32b. This suppresses water leakage from between the suction port 32b and the liner ring 22e. Furthermore, the pressure difference between the inner and outer surfaces of the suction port 32b increases as the rotational speed of the impeller 30 increases. Therefore, the larger the pressure difference between the inner and outer surfaces of the suction port 32b, the closer the suction port 32b approaches or comes into contact with the liner ring 22e, thus suppressing water leakage from between the liner ring 22e and the suction port 32b even in the high-pressure range (high rotational speed range).

[0048] Furthermore, the end face 22e1 of the liner ring 22e and the end face 32b1 of the suction port 32b may be planes perpendicular to the axial direction and can be easily machined. Therefore, the impeller 30 can be manufactured at a reduced cost and with improved machining accuracy, thereby suppressing variations in the performance of the impeller 30 (pump device 1) caused by machining accuracy. In this embodiment, when the end of the suction port 32b is machined to be a plane perpendicular to the axial direction, the suction port 32b is inclined with respect to the axial direction, so the end face 32b1 is inclined with respect to the suction port 32b. Also, since the end face 32b1 is formed at an inclination with respect to the suction port 32b, the radial length of the end face 32b1 is greater than the width of the wall surface of the suction port 32b. As a result, the area of ​​the end face 32b1 of the suction port 32b facing the end face 22e1 of the liner ring 22e increases, and the gap becomes smaller, thereby reducing water leakage to the primary side.

[0049] Furthermore, because the impeller 30 is configured such that the end face 32b1 of the suction port 32b is brought close to or in contact with the liner ring 22e by the pressure difference between the inner and outer surfaces of the suction port 32b, the impeller 30 is allowed to deform due to the pressure difference between the inner and outer surfaces of the suction port 32b. Therefore, the impeller 30 does not need to suppress the deformation of the suction port 32b, and thus does not need to increase the wall thickness or reinforce it, and thus does not increase manufacturing costs, weight, or manufacturing man-hours.

[0050] Furthermore, by making the suction port 32b of the impeller 30 bell-mouth shaped, the opening shape (inner diameter) at the end of the suction port 32b can be the same as that of other impellers with straight suction ports, such as resin impellers. Therefore, the inner diameter of the opening at the tip of the suction port 32b (mouth inner diameter) can be made to correspond to the inner diameter of the discharge portion 22f1 of the guide vane 22f. Thus, the impeller 30 can be designed in the same way as other different impellers, and a design that does not depend on the mouth outer diameter becomes possible. Therefore, the impeller 30 can be applied to guide vanes 22f and liner rings 22e that are already used in other impellers. In particular, this is possible even if the impeller 30 is a pressed impeller, as in this embodiment. Therefore, the impeller 30 can share parts of the pump casing 22 that come into contact with or are close to the impeller 30, such as guide vanes 22f and liner rings 22e, with other impellers. Therefore, the impeller 30 can improve the design flexibility of the pump device 1.

[0051] These factors allow for a transition from a molded impeller to a press-formed impeller without compromising performance. In other words, even when the design of the impeller 30 is changed from a cast or resin-molded impeller to a press-formed impeller, the guide vanes 22f can be reused, and performance can be ensured even if the inner diameter is increased to match the parts.

[0052] Furthermore, the impeller 30 has a bell-mouth shape for its suction port 32b, which rectifies the water flow and allows for smooth introduction, thereby suppressing the generation of cavitation, especially when the large-volume pump 12 is in operation.

[0053] As described above, according to the impeller 30 and pump device 1 of one embodiment of the present invention, the suction port 32b is formed in a bell mouth shape, and the suction port 32b can be deformed toward the liner ring 22e facing the suction port 32b in the axial direction by the pressure difference between the inner and outer circumferences of the suction port 32b, thereby reducing the gap between the liner ring 22e and the suction port 32b when the impeller 30 rotates. Therefore, the impeller 30 and pump device 1 can suppress leakage at the suction port 32b.

[0054] In the example described above, the pump device 1 is described in which the end face 22e1 of the liner ring 22e and the end face 32b1 of the suction port 32b are formed on a plane perpendicular to the axial direction, but it is not limited to this. That is, the pump device 1 (impeller 30) is configured such that the end face 32b1 of the suction port 32b is brought closer to or in contact with the liner ring 22e when the pump is in operation compared to when the pump is not in operation, due to the inner circumferential surface side of the suction port 32b and the pressure difference. In this case, the end face 22e1 of the liner ring 22e and the end face 32b1 of the suction port 32b, which are facing each other in the axial direction, may be inclined surfaces that intersect in both the axial direction and a direction perpendicular to the axial direction.

[0055] Furthermore, to mitigate noise and shock during sliding between the two components, the suction port 32b and the liner ring 22e of the impeller 30 may be made of a softer material, or the thickness of the suction port 32b may be made thinner than the thickness of other parts of the impeller 30 to promote deformation. Also, for example, the surface shroud 32 of the impeller 30 may be made thinner at the suction port 32b than at the fixed part 32a, or the suction port 32b may be made of a softer material than the fixed part 32a, so that the suction port 32b is more easily deformed by external forces than the fixed part 32a.

[0056] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of Symbols]

[0057] 1...Pump device, 11...Motor, 11a...Motor casing, 12...Pump, 13...Base, 21...Rotating shaft, 22...Pump casing, 22a...Suction section, 22b...Housing section, 22c...Discharge section, 22d...Inner casing, 22e...Liner ring, 22e1...End face, 22f...Guide vane, 22f1...Discharge section, 23...Casing cover, 30...Impeller, 31...Back shroud, 31a...Opening, 32...Front shroud, 32a...Fixed section, 32b...Suction port (mouth), 32b1...End face, 32c...Continuous section, 33...Blade, 33a...End face, 33b...Top, 33c...Side, 34...Impeller hub, 34a...Seat section, 34b...Boss section, 34c...Hole section.

Claims

1. An impeller having a liner ring and used in a pump that sends out water, A disc-shaped back shroud, Multiple blades are arranged along the circumferential direction of the back shroud and fixed to the back shroud, An intake port is formed that gradually decreases in diameter from the tip toward the blade side, and the end of the intake port is positioned opposite the back shroud, which faces the liner ring in the axial direction, and is fixed to the plurality of blades, An impeller equipped with the following features.

2. The impeller according to claim 1, wherein when the water is discharged, the outer surface of the suction port receives a higher pressure than the inner surface of the suction port.

3. The impeller according to claim 1, wherein the portion of the table shroud having the smallest inner diameter is located radially closer to the center than the end of the intake port and the inner circumferential surface of the liner ring.

4. The impeller according to claim 2, wherein the end face of the suction port and the end face of the liner ring are aligned in a direction perpendicular to the axial direction.

5. Pump casing and, An inner casing housed within the pump casing, A liner ring housed in the inner casing, An impeller according to any one of claims 1 to 4, housed in the inner casing and facing the liner ring in the axial direction, A pumping device equipped with the following features.

Images