pump

Abstract

The present invention relates to a pump for transferring a liquid. This pump (1) comprises an impeller (4) and a pump casing (5) for accommodating the impeller (4). The pump casing (5) includes a guide member (30) facing a front edge part (20) of the impeller (4). The guide member (30) has a front side surface (36) constituting the front side of the guide member (30) in a rotation direction of the impeller (4). When viewed from a rotation axis (CL) direction of the impeller (4), the angle formed by the front side surface (36) and the front edge part (20) in conjunction with the rotation of the impeller (4) is maintained at 90 degrees or more.

Description

Pump

[0001] The present invention relates to a pump for transferring a liquid.

[0002] A pump (particularly, a centrifugal pump) is used to transfer a liquid such as sewage flowing through a sewer pipe.

[0003] Japanese Patent Application Laid-Open No. 2019-143630

[0004] Such sewage may contain foreign substances such as fibrous substances and solid substances. If such foreign substances adhere to and accumulate on the blades of the impeller, there is a risk that the pump will be blocked by the foreign substances.

[0005] Therefore, an object of the present invention is to provide a pump that can prevent the pump from being blocked by foreign substances.

[0006] In one aspect, a pump is provided that includes an impeller and a pump casing that houses the impeller. The pump casing includes a guide member that faces the leading edge of the impeller. The guide member has a front side surface that constitutes the front side of the guide member in the rotational direction of the impeller. When viewed from the rotational axis direction of the impeller, the angle formed between the front side surface and the leading edge of the impeller as the impeller rotates is maintained at 90 degrees or more. In one aspect, the front side surface has a curved shape when viewed from the rotational axis direction. In one aspect, the angle formed between the front side surface and the leading edge of the impeller is maintained constant as the impeller rotates. In one aspect, the angle formed between the front side surface and the leading edge of the impeller gradually increases as the impeller rotates. In one aspect, the angle formed between the front side surface and the leading edge of the impeller gradually decreases as the impeller rotates.

[0007] In one embodiment, the pump casing has a groove formed on its inner surface, the groove being positioned adjacent to the guide member. In one embodiment, the front edge has a front corner located in front of the front edge in the rotational direction of the impeller, the front corner extending from the base end of the front corner connected to the boss portion of the impeller to the tip of the front corner radially outward of the impeller, the front side extending from the base end of the front side connected to the pump casing to the tip of the front side radially inward of the impeller, the radial distance of the impeller from the axis of rotation to the tip of the front side being less than or equal to the radial distance of the impeller from the axis of rotation to the base end of the front corner, and the radial distance of the impeller from the axis of rotation to the base end of the front side being greater than or equal to the radial distance of the impeller from the axis of rotation to the tip of the front corner.

[0008] In one embodiment, the pump casing has a suction port, and the guide member protrudes radially inward from the pump casing. In another embodiment, the pump casing further has a volute chamber having a shape surrounding the impeller, and a discharge port connected to the volute chamber, and the guide member is positioned on the opposite side of the discharge port with respect to the center of the suction port.

[0009] The pump casing is equipped with a guide member facing the leading edge of the impeller, and the angle between the front side of the guide member and the leading edge of the impeller is maintained at 90 degrees or more when the impeller is rotating. Therefore, even if foreign matter contained in the liquid is drawn into the pump casing, the foreign matter will not be trapped between the front side of the guide member and the leading edge, but will be pushed outward along the front side of the guide member as the impeller rotates. As a result, blockage of the pump by foreign matter can be prevented.

[0010] This figure shows one embodiment of a pump device. This is a view of the impeller, pump casing, and guide member from the axial direction. This is a perspective view showing one embodiment of the casing liner and guide member. Figure 4A shows the cross-sectional shape of the guide member. Figure 4B shows the cross-sectional shape of the guide member. Figure 4C shows the cross-sectional shape of the guide member. This is a view of the guide member and its leading edge from the direction of the rotation axis of the impeller. This figure illustrates how the positional relationship between the front side surface of the guide member and the leading edge of the impeller changes as the impeller rotates. This figure shows another embodiment of the positional relationship between the front side surface of the guide member and the leading edge of the impeller as the impeller rotates. This figure shows yet another embodiment of the positional relationship between the front side surface of the guide member and the leading edge of the impeller as the impeller rotates.

[0011] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a diagram showing one embodiment of the pump device PA. As shown in Figure 1, the pump device PA includes a pump 1 for transferring liquid and a motor 2 for driving the pump 1. In the embodiment shown in Figure 1, the pump 1 is a centrifugal pump for transferring liquid such as sewage flowing through a sewer pipe.

[0012] Pump 1 comprises a rotating shaft 3 connected to a motor 2, an impeller 4 fixed to the end of the rotating shaft 3, and a pump casing 5 housing the impeller 4. The rotating shaft 3 is rotated by the motor 2, and the impeller 4 rotates together with the rotating shaft 3 within the pump casing 5. A mechanical seal 6 is positioned between the motor 2 and the impeller 4, and is mounted on the rotating shaft 3. The mechanical seal 6 prevents liquid drawn into the pump 1 from entering the motor 2.

[0013] The pump casing 5 comprises a casing body 10 arranged around the impeller 4 and a casing liner 11 connected to the casing body 10. The casing body 10 has a volute chamber 13 formed inside and a discharge port 14 connected to the volute chamber 13. The volute chamber 13 has a shape that surrounds the impeller 4. The casing liner 11 has a suction port 12 formed in its central part.

[0014] The impeller 4 is fixed to the end of the rotating shaft 3 by fasteners 7. When the impeller 4 rotates due to the drive of the motor 2, the liquid is drawn in through the intake port 12. The liquid is given kinetic energy by the rotation of the impeller 4, and as the liquid passes through the volute chamber 13, the kinetic energy is converted into pressure, and the liquid is pressurized. The pressurized liquid is discharged from the discharge port 14. The blades 15 of the impeller 4 face the inner surface 11a of the casing liner 11, and a gap of a predetermined size is formed between the blades 15 and the inner surface 11a.

[0015] Figure 2 is a view of the impeller 4, pump casing 5, and guide member 30 (described later) from the axial direction. As shown in Figure 2, the impeller 4 comprises a plurality of blades 15 (two in this embodiment) and a boss portion 16 to which the blades 15 are fixed. The blades 15 rotate together with the rotation axis 3 around the boss portion 16 (see solid arrow in Figure 2).

[0016] As shown in Figure 2, the pump casing 5 has a tongue portion 25 that forms the starting point of the volute chamber 13. The volute chamber 13 extends along the circumference of the impeller 4, and the liquid flowing through the volute chamber 13 is divided at the tongue portion 25. Therefore, most of the liquid flows to the discharge port 14, while some of the liquid circulates through the volute chamber 13 (see the dotted arrow in Figure 2).

[0017] In the embodiment shown in Figure 2, the wing 15 is a swept wing. More specifically, the wing 15 has a leading edge portion 20 that extends spirally from a boss portion 16 and a trailing edge portion 21 that extends spirally from the leading edge portion 20. The leading edge portion 20 and the trailing edge portion 21 are connected to each other and are integrally constructed.

[0018] The leading edge 20 is positioned radially inward of the intake port 12. The trailing edge 21 faces the inner surface 11a of the casing liner 11 (see Figure 1). Therefore, when the casing liner 11 is viewed from the axis CL direction of the rotation shaft 3 (i.e., the rotation axis CL direction of the impeller 4), the leading edge 20 is positioned to be exposed from the casing liner 11, and the trailing edge 21 is positioned on the back side of the casing liner 11.

[0019] As described above, the fluid handled by the pump device PA may contain foreign matter such as fibrous materials and solid materials. The leading edge 20 of the blade 15 is located radially inward of the suction port 12. Therefore, when the fluid is drawn into the suction port 12 by the rotation of the impeller 4, the foreign matter may adhere to and accumulate on the leading edge 20. In this state, when the impeller 4 rotates, the foreign matter may become trapped in the gap between the trailing edge 21 and the inner surface 11a of the casing liner 11, potentially causing the pump 1 to become blocked.

[0020] Therefore, in order to prevent blockage of the pump 1 by foreign matter, the pump 1 (more specifically, the pump casing 5) is equipped with a guide member 30 that pushes the foreign matter toward the radially outward direction of the impeller 4.

[0021] Figure 3 is a perspective view showing one embodiment of the casing liner 11 and guide member 30. The guide member 30 is fixed to the casing liner 11 of the pump casing 5. More specifically, the guide member 30 is fixed to the inner surface 11a that forms the suction port 12 of the casing liner 11. The guide member 30 protrudes radially inward from the casing liner 11 toward the suction port 12 so as to obstruct the flow path of liquid passing through the suction port 12. In this embodiment, the guide member 30 is made of a different material from the casing liner 11. The guide member 30 is fixed to a guide member mounting portion (not shown) provided on the casing liner 11 by fasteners (not shown). With this configuration, even if the guide member 30 wears out, the operator can easily replace the guide member 30. In one embodiment, the guide member 30 may be a member integrally molded with the casing liner 11.

[0022] The guide member 30 has an upper surface 35 that faces the leading edge 20 of the blade 15 when the impeller 4 is housed in the pump casing 5, a front side surface 36 that constitutes the front side of the guide member 30 in the direction of rotation of the impeller 4 (see arrow in Figure 2), a rear side surface 37 that constitutes the rear side of the guide member 30 in the direction of rotation of the impeller 4, and a lower surface 38 located on the opposite side of the upper surface 35. A gap of a predetermined size is formed between the leading edge 20 of the impeller 4 housed in the pump casing 5 and the upper surface 35 of the guide member 30. The size of this gap is such that foreign matter that could cause the pump 1 to become blocked cannot enter.

[0023] Figures 4A to 4C show the cross-sectional shape of the guide member 30. In this embodiment, as shown in Figure 4A, the front side surface 36 and the rear side surface 37 are connected to the upper surface 35 and the lower surface 38, and the cross-sectional shape of the guide member 30 is rectangular. In this embodiment, the angle θa between the upper surface 35 and the front side surface 36 is a right angle (90 degrees).

[0024] In other embodiments, as shown in Figure 4B, the angle θa between the upper surface 35 and the front side surface 36 may be acute. In the embodiment shown in Figure 4B, the cross-sectional shape of the guide member 30 is trapezoidal. In yet another embodiment, as shown in Figure 4C, the guide member 30 does not have a lower surface 38, and the longitudinal cross-sectional shape of the guide member 30 may be triangular. Although not shown, the angle θa may be obtuse if the guide member 30 can achieve the effect of flushing away foreign matter, which will be described in detail later.

[0025] As shown in Figure 3, the casing liner 11 of the pump casing 5 has grooves 40 formed on its inner surface. In this embodiment, the casing liner 11 has a plurality of grooves 40 arranged along the circumferential direction of the suction port 12. One of the plurality of grooves 40 is located upstream of the guide member 30 in the rotational direction of the impeller 4 and is adjacent to the guide member 30. More specifically, the plurality of grooves 40 are formed on the inner surface 11a of the casing liner 11 and extend from the suction port 12 toward the volute chamber 13. The front side surface 36 of the guide member 30 is connected to the starting end 40a of the groove 40, and the ending end 40b of the groove 40 is connected to the volute chamber 13.

[0026] In one embodiment, the casing liner 11 may have a groove 40 adjacent to the guide member 30. In another embodiment, the casing liner 11 may not have a groove 40.

[0027] When the impeller 4 rotates due to the drive of the motor 2, foreign matter contained in the liquid is pushed radially outward from the impeller 4 along the front side surface 36 of the guide member 30 located at the suction port 12. The foreign matter pushed outward from the impeller 4 is guided into a groove 40 formed in the casing liner 11, moves along the groove 40, and is discharged into the volute chamber 13 at the end 40b of the groove 40. The foreign matter is then discharged to the outside through the discharge port 14.

[0028] As shown in Figure 2, the guide member 30 is positioned on the opposite side of the discharge port 14 with respect to the center of the suction port 12. The center of the suction port 12 coincides with the axis CL of the rotation axis 3 (i.e., the rotation axis CL of the impeller 4). The tongue portion 25 is positioned adjacent to the discharge port 14. With this arrangement, foreign matter is discharged into the volute chamber 13 at a position opposite to the tongue portion 25. Subsequently, the foreign matter moves through the volute chamber 13 due to the flowing liquid while being subjected to centrifugal force. Therefore, the foreign matter is discharged to the outside from the discharge port 14 without getting caught on the tongue portion 25.

[0029] Figure 5 shows the guide member 30 and the front edge portion 20 as viewed from the rotation axis CL direction of the impeller 4. As shown in Figure 5, the front edge portion 20 has a front corner portion 27 that constitutes the front side of the front edge portion 20 in the rotation direction of the impeller 4 indicated by the arrow in Figure 5, and a rear corner portion 28 that constitutes the rear side of the front edge portion 20 in the rotation direction of the impeller 4. The front corner portion 27 extends from the base end portion 27a of the front corner portion 27 connected to the boss portion 16, curving radially outward from the impeller 4, to the tip portion 27b of the front corner portion 27. The front side surface 36 of the guide member 30 extends from the base end portion 36a of the front side surface 36 connected to the casing liner 11, curving radially inward from the impeller 4, to the tip portion 36b of the front side surface 36.

[0030] The radial distance d1 of the impeller 4 from the rotation axis CL to the tip 36b of the front side surface 36 is less than or equal to the radial distance d3 of the impeller 4 from the rotation axis CL to the base end 27a of the front corner 27. In this embodiment, distance d1 is the same as distance d3, and distances d1 and d3 are equal to the radius of the boss portion 16. Also, the radial distance d2 of the impeller 4 from the rotation axis CL to the base end 36a of the front side surface 36 is greater than or equal to the radial distance d4 of the impeller 4 from the rotation axis CL to the tip 27b of the front corner 27. In this embodiment, distance d2 is the same as distance d4, and distances d2 and d4 are equal to the radius of the intake port 12. With this configuration, the guide member 30 can push any foreign matter sucked in from the suction port 12 towards the radially outward direction of the impeller 4 by the rotation of the impeller 4, regardless of its position on the leading edge portion 20.

[0031] The positional relationship between the guide member 30 and the leading edge portion 20 changes as the impeller 4 rotates. Initially, the tip-side region S1 of the guide member 30, where the tip portion 36b of the guide member 30 is located, faces the base-side region S4 of the leading edge portion 20, where the base portion 27a of the leading edge portion 20 is located. Next, the central region S2 of the guide member 30 faces the central region S5 of the leading edge portion 20. Subsequently, the base-side region S3 of the guide member 30, where the base portion 36a of the guide member 30 is located, faces the tip-side region S6 of the leading edge portion 20, where the tip portion 27b of the leading edge portion 20 is located. The central region S2 of the guide member 30 is located between the tip-side region S1 and the base-side region S3. The central region S5 of the leading edge portion 20 is located between the base-side region S4 and the tip-side region S6.

[0032] Figure 6 illustrates how the positional relationship between the front side surface 36 of the guide member 30 and the leading edge 20 of the impeller 4 changes as the impeller 4 rotates. Positional relationship A in Figure 6 shows that the tip-side region S1 of the guide member 30 is facing the base-side region S4 of the leading edge 20. Positional relationship B in Figure 6 shows that the central region S2 of the guide member 30 is facing the central region S5 of the leading edge 20. Positional relationship C in Figure 6 shows that the base-side region S3 of the guide member 30 is facing the tip-side region S6 of the leading edge 20.

[0033] The positional relationship between the guide member 30 and the leading edge portion 20 changes from positional relationship A to positional relationship B and then to positional relationship C as the impeller 4 rotates. Therefore, when viewed from the direction of the rotation axis CL of the impeller 4, the angle between the front side surface 36 of the guide member 30 and the leading edge portion 20 of the impeller 4 (more specifically, the front corner portion 27) includes angle α1 in positional relationship A, angle α2 in positional relationship B, and angle α3 in positional relationship C.

[0034] The angle between the front side surface 36 and the front edge portion 20 (more specifically, the front corner portion 27) is the angle between the tangent to the front side surface 36 and the tangent to the front edge portion 20 (more specifically, the front corner portion 27) at the intersection of the front side surface 36 and the front edge portion 20 (more specifically, the front corner portion 27), when viewed from the direction of the rotation axis CL of the impeller 4.

[0035] In other words, the angle α1 in positional relationship A is the angle between the tangent T1 of the front side surface 36 and the tangent T2 of the front corner portion 27 at the intersection point P1 of the front side surface 36 and the base end region S4 of the front edge portion 20 (more specifically, the front corner portion 27), when viewed from the direction of the rotation axis CL of the impeller 4.

[0036] Angle α2 in positional relationship B is the angle between the tangent T3 of the front side surface 36 and the tangent T4 of the front corner 27 at the intersection P2 of the central region S2 of the front side surface 36 and the central region S5 of the front edge 20 (more specifically, the front corner 27), when viewed from the direction of the rotation axis CL of the impeller 4. Angle α3 in positional relationship C is the angle between the tangent T5 of the front side surface 36 and the tangent T6 of the front corner 27 at the intersection P3 of the base end region S3 of the front side surface 36 and the tip end region S6 of the front edge 20 (more specifically, the front corner 27), when viewed from the direction of the rotation axis CL of the impeller 4.

[0037] When viewed from the direction of the rotation axis CL of the impeller 4, the angle between the front side surface 36 and the leading edge 20 as the impeller 4 rotates is maintained at 90 degrees or more. On the other hand, the angle between the front side surface 36 and the leading edge 20 as the impeller 4 rotates is 120 degrees or less. The front side surface 36 of the guide member 30 has a curved shape so that the angle between the front side surface 36 and the leading edge 20 as the impeller 4 rotates is always 90 degrees or more when viewed from the direction of the rotation axis CL of the impeller 4.

[0038] In this specification, "90 degrees" in "the angle between the front side surface 36 and the leading edge 20 as the impeller 4 rotates is 90 degrees or more" includes angles smaller than 90 degrees as a tolerance / error range that may occur due to manufacturing conditions, etc. In this specification, "120 degrees" in "the angle between the front side surface 36 and the leading edge 20 as the impeller 4 rotates is 120 degrees or less" includes angles larger than 120 degrees as a tolerance / error range that may occur due to manufacturing conditions, etc.

[0039] In this embodiment, angles α1, α2, and α3 are 90 degrees, and the angle between the front side surface 36 and the leading edge 20 remains constant at 90 degrees as the impeller 4 rotates. The angle between the front side surface 36 and the leading edge 20 remains constant at 90 degrees even as the positional relationship changes from A to B as the impeller 4 rotates. The angle between the front side surface 36 and the leading edge 20 remains constant at 90 degrees even as the positional relationship changes from B to C as the impeller 4 rotates.

[0040] As the impeller 4 rotates, the angle between the front side surface 36 and the leading edge 20 is maintained at 90 degrees or more. As a result, foreign matter present between the guide member 30 and the leading edge 20 is not trapped between the front side surface 36 and the leading edge 20 of the guide member 30, but is pushed outward along the front side surface 36. Consequently, blockage of the pump 1 by foreign matter can be prevented.

[0041] Figure 7 shows another embodiment of the positional relationship between the front side surface 36 of the guide member 30 and the leading edge 20 of the impeller 4 as the impeller 4 rotates. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to Figures 1 to 6, so the redundant explanation is omitted. In this embodiment, the angle between the front side surface 36 and the leading edge 20 gradually increases as the impeller 4 rotates. That is, angle α2 may be greater than angle α1, and angle α3 may be greater than angle α2 (α1 < α2 < α3). In this embodiment as well, the minimum value of the angle between the front side surface 36 and the leading edge 20 is 90 degrees or more. The front side surface 36 of the guide member 30 has a curved shape so that the angle between the front side surface 36 and the leading edge 20 gradually increases as the impeller 4 rotates when viewed from the direction of the rotation axis CL of the impeller 4.

[0042] As shown in Figure 7, in this embodiment, for example, angle α1 is 90 degrees, angle α2 is 105 degrees, and angle α3 is 115 degrees. Between positional relationship A and positional relationship B, the angle between the front side surface 36 and the leading edge 20 gradually increases from angle α1 to angle α2 as the impeller 4 rotates. Between positional relationship B and positional relationship C, the angle between the front side surface 36 and the leading edge 20 gradually increases from angle α2 to angle α3 as the impeller 4 rotates.

[0043] Also in this embodiment, by maintaining the angle formed by the front side surface 36 and the leading edge portion 20 as the impeller 4 rotates at 90 degrees or more, foreign matter existing between the guide member 30 and the leading edge portion 20 is not caught and retained between the front side surface 36 of the guide member 30 and the leading edge portion 20, and the foreign matter is washed outward along the front side surface 36. As a result, clogging of the pump 1 by foreign matter can be prevented.

[0044] FIG. 8 is a diagram showing still another embodiment of the positional relationship between the front side surface 36 of the guide member 30 and the leading edge portion 20 of the impeller 4 as the impeller 4 rotates. The configuration and operation of this embodiment not particularly described are the same as those of the embodiment described with reference to FIGS. 1 to 6, and thus the overlapping description thereof is omitted. In this embodiment, the angle formed by the front side surface 36 and the leading edge portion 20 gradually decreases as the impeller 4 rotates. That is, the angle α2 may be smaller than the angle α1, and the angle α3 may be smaller than the angle α2 (α1 > α2 > α3). Also in this embodiment, the minimum value of the angle formed by the front side surface 36 and the leading edge portion 20 is 90 degrees or more. When viewed from the direction of the rotation axis center CL of the impeller 4, the front side surface 36 of the guide member 30 has a curved shape such that the angle formed by the front side surface 36 and the leading edge portion 20 gradually decreases as the impeller 4 rotates.

[0045] As shown in FIG. 8, in this embodiment, as an example, the angle α1 is 115 degrees, the angle α2 is 95 degrees, and the angle α3 is 90 degrees. Between the positional relationship A and the positional relationship B, the angle formed by the front side surface 36 and the leading edge portion 20 gradually decreases from the angle α1 to the angle α2 as the impeller 4 rotates. Between the positional relationship B and the positional relationship C, the angle formed by the front side surface 36 and the leading edge portion 20 gradually decreases from the angle α2 to the angle α3 as the impeller 4 rotates.

[0046] Also in this embodiment, by maintaining the angle formed by the front side surface 36 and the leading edge portion 20 as the impeller 4 rotates at 90 degrees or more, foreign matter existing between the guide member 30 and the leading edge portion 20 is not caught and retained between the front side surface 36 of the guide member 30 and the leading edge portion 20, and the foreign matter is washed outward along the front side surface 36. As a result, clogging of the pump 1 by foreign matter can be prevented.

[0047] In one embodiment, the angle formed between the front side surface 36 and the leading edge 20 may increase and decrease, or decrease and increase, as the impeller 4 rotates. For example, the angle formed between the front side surface 36 and the leading edge 20 may increase from the positional relationship A to the positional relationship B and decrease from the positional relationship B to the positional relationship C as the impeller 4 rotates. That is, the angle α2 may be larger than the angle α1, and the angle α3 may be smaller than the angle α2 (α1 < α2 > α3). Also in this case, the angle formed between the front side surface 36 and the leading edge 20 is maintained at 90 degrees or more. For example, the angle α1 is 90 degrees, the angle α2 is 100 degrees, and the angle α3 is 90 degrees.

[0048] In another example, the angle formed between the front side surface 36 and the leading edge 20 may decrease from the positional relationship A to the positional relationship B and increase from the positional relationship B to the positional relationship C as the impeller 4 rotates. That is, the angle α2 may be smaller than the angle α1, and the angle α3 may be larger than the angle α2 (α1 > α2 < α3). Also in this case, the angle formed between the front side surface 36 and the leading edge 20 is maintained at 90 degrees or more. For example, the angle α1 is 100 degrees, the angle α2 is 90 degrees, and the angle α3 is 100 degrees.

[0049] The above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to implement the present invention. Various modifications of the above embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention should not be limited to the described embodiments, but should be in the broadest scope in accordance with the technical idea defined by the claims.

[0050] The present invention can be used for a pump for transferring a liquid.

[0051] 1 Pump 2 Motor 3 Rotating shaft 4 Impeller 5 Pump casing 6 Mechanical seal 7 Fasteners 10 Casing body 11 Casing liner 11a Inner surface 12 Suction port 13 Volute chamber 14 Discharge port 15 Blade 16 Boss 20 Leading edge 21 Trailing edge 25 Tongue 27 Front corner 28 Rear corner 30 Guide member 35 Top surface 36 Front side surface 37 Rear side surface 38 Bottom surface 40 Groove 40a Start end 40b End end PA Pump device

Claims

1. A pump comprising an impeller and a pump casing housing the impeller, wherein the pump casing includes a guide member facing the leading edge of the impeller, the guide member having a front side surface that constitutes the front side of the guide member in the rotational direction of the impeller, and the angle between the front side surface and the leading edge of the impeller, as viewed from the rotational axis direction of the impeller, is maintained at 90 degrees or more as the impeller rotates.

2. The pump according to claim 1, wherein the front side surface has a curved shape when viewed from the direction of the rotation axis.

3. The pump according to claim 1, wherein the angle between the front side surface and the leading edge is maintained constant as the impeller rotates.

4. The pump according to claim 1, wherein the angle between the front side surface and the leading edge gradually increases with the rotation of the impeller.

5. The pump according to claim 1, wherein the angle between the front side surface and the leading edge gradually decreases as the impeller rotates.

6. The pump according to claim 1, wherein the pump casing has a groove formed on its inner surface, the groove being arranged adjacent to the guide member.

7. The pump according to claim 1, wherein the front edge portion has a front corner portion located in front of the front edge portion in the rotational direction of the impeller, the front corner portion extends from the base end of the front corner portion connected to the boss portion of the impeller to the tip of the front corner portion radially outward of the impeller, the front side portion extends from the base end of the front side portion connected to the pump casing to the tip of the front side portion radially inward of the impeller, the radial distance of the impeller from the rotational axis to the tip of the front side portion is less than or equal to the radial distance of the impeller from the rotational axis to the base end of the front corner portion, and the radial distance of the impeller from the rotational axis to the base end of the front side portion is greater than or equal to the radial distance of the impeller from the rotational axis to the tip of the front corner portion.

8. The pump according to claim 1, wherein the pump casing has a suction port, and the guide member protrudes radially inward from the pump casing toward the suction port.

9. The pump according to claim 8, wherein the pump casing further comprises a volute chamber having a shape surrounding the impeller and a discharge port connected to the volute chamber, and the guide member is positioned on the opposite side of the discharge port with respect to the center of the suction port.

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