pump

Abstract

A pump casing is provided that can prevent blockage of the pump by foreign matter. [Solution] The pump 1 comprises an impeller 4 and a pump casing 5 that houses the impeller 4. The pump casing 5 is provided with a guide member 30 facing the front edge 20 of the impeller 4. The guide member 30 has a front side surface 36 that constitutes the front side of the guide member 30 in the rotational direction of the impeller 4. When viewed from the direction of the rotational axis CL of the impeller 4, the angle between the front side surface 36 and the front edge 20 as the impeller 4 rotates is maintained at 90 degrees or more.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

Means for Solving the Problems

[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 portion of the impeller. The guide member has a front side surface that constitutes the front side of the guide member in the rotation direction of the impeller. When viewed from the rotation axis direction of the impeller, the angle formed by the front side surface and the leading edge portion accompanying the rotation of the impeller is maintained at 90 degrees or more. In one aspect, the front side surface has a curved shape when viewed from the rotation axis direction. In one embodiment, the angle between the front side and the leading edge is kept constant as the impeller rotates. In one embodiment, the angle between the front side surface and the leading edge gradually increases as the impeller rotates. In one embodiment, the angle between the front side surface and the leading edge gradually decreases as the impeller rotates.

[0007] In one embodiment, the pump casing has a groove formed on its inner surface, and the groove is positioned adjacent to the guide member. In one embodiment, the front edge portion has a front corner portion located on the front side 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.

[0008] In one embodiment, the pump casing has a suction port, and the guide member protrudes radially inward from the pump casing toward the suction port. In one embodiment, the pump casing further includes 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. [Effects of the Invention]

[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. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows one embodiment of a pump device. [Figure 2] This is a view of the impeller, pump casing, and guide members from the axial direction. [Figure 3] This is a perspective view showing one embodiment of a casing liner and guide member. [Figure 4] Figures 4(a) to 4(c) show the cross-sectional shape of the guide member. [Figure 5] This diagram shows the guide member and the leading edge as viewed from the direction of the impeller's rotation axis. [Figure 6] This diagram illustrates how the positional relationship between the front side of the guide member and the leading edge of the impeller changes as the impeller rotates. [Figure 7] 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 it changes with the rotation of the impeller. [Figure 8] 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 it changes with the rotation of the impeller. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows one embodiment of a 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 outlet 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] FIG. 2 is a view of the impeller 4, the pump casing 5, and a guide member 30 described later, as viewed axially. As shown in FIG. 2, the impeller 4 includes a plurality (two in this embodiment) of blades 15 and a boss portion 16 to which the blades 15 are fixed. The blades 15 rotate together with the rotating shaft 3 about the boss portion 16 (see the solid-line arrow in FIG. 2).

[0016] As shown in FIG. 2, the pump casing 5 has a tongue portion 25 that forms the start of the volute chamber 13. The volute chamber 13 extends along the circumferential direction of the impeller 4, and the liquid flowing through the volute chamber 13 is split at the tongue portion 25. Therefore, most of the liquid flows to the discharge port 14, while a part of the liquid circulates through the volute chamber 13 (see the dotted-line arrow in FIG. 2).

[0017] In the embodiment shown in FIG. 2, the blade 15 is a backward-curved blade. More specifically, the blade 15 has a leading edge portion 20 that extends spirally from the 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 formed.

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

[0019] As described above, the liquid to be handled by the pump device PA may contain foreign matters such as fibrous substances and solid substances. The leading edge portion 20 of the blade 15 is disposed radially inside the suction port 12. Therefore, when the liquid to be handled is sucked into the suction port 12 by the rotation of the impeller 4, foreign matters may adhere to and accumulate on the leading edge portion 20. In this state, when the impeller 4 rotates, the foreign matters may be caught in the gap between the trailing edge portion 21 and the inner surface 11a of the casing liner 11, and as a result, there is a risk that the pump 1 may be 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 blockage of the pump 1 cannot enter.

[0023] Figures 4(a) to 4(c) show the cross-sectional shape of the guide member 30. In this embodiment, as shown in Figure 4(a), 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 4(b), the angle θa between the upper surface 35 and the front side surface 36 may be acute. In the embodiment shown in Figure 4(b), the cross-sectional shape of the guide member 30 is trapezoidal. In yet another embodiment, as shown in Figure 4(c), 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 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. The foreign matter is then moved through the volute chamber 13 by 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 opposite 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 opposite 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 opposite 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 leading 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 leading edge portion 20 (more specifically, the front corner portion 27) at the intersection of the front side surface 36 and the leading 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 P1 of the tip-side region S1 of the front side surface 36 and the base-side 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] In this embodiment as well, by maintaining an angle of 90 degrees or more between the front side surface 36 and the leading edge 20 as the impeller 4 rotates, 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 instead pushed outward along the front side surface 36. As a result, blockage of the pump 1 by foreign matter can be prevented.

[0044] Figure 8 shows yet 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 decreases as the impeller 4 rotates. That is, angle α2 may be smaller than angle α1, and angle α3 may be smaller 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 decreases as the impeller 4 rotates when viewed from the direction of the rotation axis CL of the impeller 4.

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

[0046] In this embodiment as well, by maintaining an angle of 90 degrees or more between the front side surface 36 and the leading edge 20 as the impeller 4 rotates, 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 instead pushed outward along the front side surface 36. As a result, blockage of the pump 1 by foreign matter can be prevented.

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

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

[0049] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but should be in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0050] 1 pump 2 motors 3 rotation axes 4-blade wheel 5 Pump casing 6 Mechanical seals 7 Fasteners 10 Casing body 11 Casing Liner 11a Inner Self 12 Inlet 13 Volute Room 14 Outlet 15 wings 16 Boss Section 20 Front edge 21 Trailing edge 25 Tongue 27 Front corner 28 Rear corner 30 Guide member 35 Top 36 Front side 37 Rear side 38 Bottom side 40 grooves 40a Starting point 40b termination PA pump system

Claims

1. The impeller and The pump casing comprises the impeller, The pump casing is provided with a guide member facing 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 rotation direction of the impeller, A pump in which, when viewed from the direction of the rotation axis of the impeller, the angle between the front side surface and the leading edge of the impeller as it rotates is maintained at 90 degrees or more.

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 and the leading edge gradually decreases as the impeller rotates.

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

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

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

9. The pump casing is, A volute chamber having a shape that surrounds the impeller, It further has a discharge port connected to the volute chamber, The pump according to claim 8, wherein 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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