pump

Abstract

To provide a pump capable of improving the efficiency of restoring liquid pressure. [Solution] The pump according to the present disclosure is a back pull-out type pump comprising an external casing that partitions an internal space, an inlet, a discharge port, and a mounting port, and a drive body having an insertion part, the insertion part comprising a rotating shaft, a plurality of impellers, and an internal casing having a peripheral wall, the peripheral wall partitioning an opening that allows the liquid discharged radially outward from the final stage impeller to pass from the radially inside to the outside, and a volute flow path connecting the opening and the discharge port is partitioned between the outer surface of the peripheral wall and the inner surface of the external casing.

Description

Technical Field

[0001] The present disclosure relates to a pump.

Background Art

[0002] Conventionally, a back pull-out type pump has been known. This type of pump is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the pump described in Patent Document 1 still has room for improvement from the viewpoint of the efficiency of pressure recovery of the liquid.

[0005] An object of the present disclosure is to provide a pump capable of improving the efficiency of pressure recovery of a liquid.

Means for Solving the Problems

[0006] A pump according to a first aspect of the present disclosure includes (1) a back pull-out type pump, an external casing that partitions an internal space, a suction port, a discharge port, and a mounting port that are continuous with the internal space, a drive body including an insertion portion that can be inserted into and removed from the internal space through the mounting port, wherein the insertion portion includes a rotating shaft, a plurality of impellers attached to the rotating shaft and arranged at intervals in the axial direction of the rotating shaft, and an internal casing including a peripheral wall that surrounds the plurality of impellers in the radial direction of the rotating shaft. Of any two of the plurality of impellers, the impeller located on the axial base end side is located downstream in the direction of the flow of the liquid flowing through the internal space compared to the impeller located on the axial tip side. The peripheral wall defines an opening that allows the liquid discharged radially outward from the final stage impeller, which is the impeller located furthest towards the base end among the plurality of impellers, to pass from the radially inside to the outside. A volute flow path connecting the opening and the discharge port is partitioned between the outer surface of the peripheral wall and the inner surface of the outer casing, in this pump.

[0007] A pump as one embodiment of the present disclosure is (2) The pump is as described in (1) above, wherein the internal casing is positioned radially outside the final stage impeller and includes guide vanes that guide the liquid discharged radially outward from the final stage impeller in an inclined direction with respect to the radial direction.

[0008] A pump as one embodiment of the present disclosure is (3) Multiple guide vanes are arranged at intervals in the circumferential direction of the rotation axis. Of the plurality of guide vanes, two guide vanes adjacent to each other in the circumferential direction define a guide channel between them that extends along the inclined direction. The pump described in (2) above has a flow channel area in which the flow channel area increases from the upstream side to the downstream side in the flow direction.

[0009] A pump as one embodiment of the present disclosure is (4) The aforementioned guide vane is, Formed on the peripheral wall, The pump according to (2) or (3) above, wherein the peripheral wall also serves as a connecting column connecting the portion located on the tip side of the opening and the portion located on the base side of the opening.

[0010] As one embodiment of the present disclosure, a pump is (5) The pump according to any one of (2) to (4) above, wherein a guide vane is not provided outside the radial direction of the impeller located on the tip side of the final-stage impeller among the plurality of impellers.

[0011] As one embodiment of the present disclosure, a pump is (6) The pump according to any one of (1) to (5) above, wherein the blade portion of the final-stage impeller and the discharge port are arranged on the same plane perpendicular to the axial direction.

Advantages of the Invention

[0012] According to the present disclosure, it is possible to provide a pump capable of improving the efficiency of pressure recovery of a liquid.

Brief Description of the Drawings

[0013] [Figure 1] It is a perspective view of the pump according to an embodiment of the present disclosure in a use state. [Figure 2] It is a perspective view of the pump shown in FIG. 1 in a disassembled state. [Figure 3] It is a cross-sectional view of the pump shown in FIG. 1 in a use state. [Figure 4] It is a cross-sectional view of the pump shown in FIG. 1 in a disassembled state. [Figure 5] It is a cross-sectional view taken at the position of line I-I in FIG. 3. [Figure 6] It is an enlarged view of part X in FIG. 5. [Figure 7] It is a perspective view showing the final-stage partial casing alone.

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the pump according to the present disclosure will be exemplarily described with reference to the drawings. The same components are denoted by the same reference numerals in each figure.

[0015] Figures 1 and 2 are perspective views showing pump 1 as one embodiment of the pump according to this disclosure. Pump 1 can be used, for example, as a water supply pump. However, the use of pump 1 is not limited thereto.

[0016] As shown in Figures 1 and 2, the pump 1 comprises an external casing 10 and a drive unit 20. Figure 1 shows the pump 1 in a state where the external casing 10 and the drive unit 20 are combined, with the drive unit 20 inserted into the internal space 10a of the external casing 10. In this state, the pump 1 can pump liquid. Figure 2 shows the pump 1 in a state where the external casing 10 and the drive unit 20 are disassembled, with the drive unit 20 being pulled out from the internal space 10a of the external casing 10. In this state, the pump 1 can be maintained. Thus, the pump 1 is a back-pull-out type pump that allows for easy maintenance by pulling out the drive unit 20 from the external casing 10. In the following, the state shown in Figure 1 will be referred to as the "operating state" and the state shown in Figure 2 will be referred to as the "disassembled state". Furthermore, unless otherwise specified, the following description will focus on the pump 1 in the operating state.

[0017] Figure 3 is a cross-sectional view of pump 1 in use. Figure 4 is a cross-sectional view of pump 1 in a disassembled state. Figure 5 is a cross-sectional view at the position of line II in Figure 3. Figure 6 is an enlarged view of section X in Figure 5.

[0018] The drive unit 20 comprises a motor 21, a casing cover 22, and an insertion section 23. The insertion section 23 comprises a rotating shaft 30, three impellers 40, and an internal casing 31. For the sake of explanation, the direction parallel to the central axis O of the rotating shaft 30 will be referred to as "axial direction A". The direction around the central axis O of the rotating shaft 30 will be referred to as "circumferential direction B". Furthermore, the radial direction of the circle centered on the central axis O of the rotating shaft 30 will be referred to as "radial direction C".

[0019] The external casing 10 comprises an external casing body 25 and legs 18. The external casing body 25 divides the internal space 10a and the suction port 12, discharge port 13, and mounting port 14 connected to the internal space 10a.

[0020] The insertion part 23 can be inserted into and removed from the internal space 10a of the external casing 10 through the mounting port 14 of the external casing 10. The pump 1 is in operation when the insertion part 23 is inserted into the internal space 10a of the external casing 10, and is disassembled when the insertion part 23 is removed from the internal space 10a of the external casing 10.

[0021] The insertion portion 23 is inserted into and removed from the internal space 10a along the axial direction A. For the sake of explanation, in the following, the direction in which the insertion portion 23 is inserted into the internal space 10a will be referred to as "tip side A1", and the direction in which the insertion portion 23 is removed from the internal space 10a will be referred to as "base end side A2".

[0022] The mounting port 14 faces the base end side A2 in the axial direction A. The discharge port 13 faces outward in the radial direction C. The suction port 12 faces the tip side A1 in the axial direction A. The leg portion 18 is capable of supporting the external casing body 25 and the drive body 20 when the rotating shaft 30 is positioned horizontally.

[0023] Motor 21 is a drive source for rotating the rotating shaft 30 in the circumferential direction B. The type of motor 21 is not particularly limited.

[0024] A casing cover 22 is attached to the motor 21. The casing cover 22 comprises a cover body 29, a shaft seal portion 26, and a sealing member 27 attached to the cover body 29. The cover body 29 is detachable from the external casing 10. The cover body 29 closes the mounting opening 14 when it is mounted on the external casing 10 with the insertion portion 23 inserted into the internal space 10a. The rotating shaft 30 passes through the cover body 29. The shaft seal portion 26 seals the space between the cover body 29 and the rotating shaft 30. The shaft seal portion 26 may be, for example, a mechanical seal. The sealing member 27 seals the space between the cover body 29 and the external casing 10. The sealing member 27 may be, for example, an O-ring.

[0025] The three impellers 40 are mounted on a rotating shaft 30 and rotate together with the rotating shaft 30 in the circumferential direction B. Each of the three impellers 40 has multiple (six in this embodiment, see Figure 5) blades 41. By rotating in the circumferential direction B, each of the three impellers 40 discharges the liquid supplied from the tip side A1 outward in the radial direction C. The impellers 40 may also have a suction function to draw liquid in from the tip side A1.

[0026] The three impellers 40 are spaced apart in the axial direction A. For the sake of explanation, the impeller 40 located at the furthest forward A1 of the three impellers 40 may be referred to as the "first stage impeller 40a," the impeller 40 located at the furthest base A2 as the "final stage impeller 40c," and the impeller 40 located between the first stage impeller 40a and the final stage impeller 40c in the axial direction A as the "middle stage impeller 40b."

[0027] Of the three impellers 40, the impeller 40 located at the base end A2 in the axial direction A is located downstream of the impeller 40 located at the tip end A1 in the axial direction A in the direction of liquid flow in the internal space 10a (hereinafter simply referred to as "liquid flow direction"). In other words, the first stage impeller 40a, the middle stage impeller 40b, and the final stage impeller 40c are arranged in this order from the upstream side to the downstream side in the direction of liquid flow.

[0028] The internal casing 31 is attached to the cover body 29. The internal casing 31 has a peripheral wall 51 that surrounds the radial C perimeter of the three impellers 40. As shown in Figures 2, 5, etc., the peripheral wall 51 defines an opening 55 that allows liquid discharged from the final stage impeller 40c to the outside in the radial C direction to pass from the inside to the outside in the radial C direction.

[0029] More specifically, the internal casing 31 comprises three sub-casings 50 stacked in the axial direction A. Each of the three sub-casings 50 contains one impeller 40. For convenience of explanation, the sub-casing 50 containing the first-stage impeller 40a may be referred to as the "first-stage sub-casing 50a," the sub-casing 50 containing the middle-stage impeller 40b as the "middle-stage sub-casing 50b," and the sub-casing 50 containing the final-stage impeller 40c as the "final-stage sub-casing 50c."

[0030] The first stage casing 50a includes a first stage peripheral wall portion 51a that surrounds the radial C of the first stage impeller 40a. The middle stage casing 50b includes a middle stage peripheral wall portion 51b that surrounds the radial C of the middle stage impeller 40b. The final stage casing 50c includes a final stage peripheral wall portion 51c that surrounds the radial C of the final stage impeller 40c. The peripheral wall 51 is formed by the first stage peripheral wall portion 51a, the middle stage peripheral wall portion 51b, and the final stage peripheral wall portion 51c being connected in the axial direction A. As shown in Figures 5 and 7, the opening 55 is partitioned by the final stage peripheral wall portion 51c.

[0031] The internal casing 31 includes a first return vane 53 and a second return vane 54. The first return vane 53 is positioned between the first stage impeller 40a and the middle stage impeller 40b in the axial direction A. The first return vane 53 guides the liquid discharged from the first stage impeller 40a radially outward in the radial direction C to the middle stage impeller 40b from the outside radially outward in the radial direction C. The first return vane 53 is provided in the middle stage partial casing 50b. The second return vane 54 is positioned between the middle stage impeller 40b and the final stage impeller 40c in the axial direction A. The second return vane 54 guides the liquid discharged from the middle stage impeller 40b radially outward in the radial direction C to the final stage impeller 40c from the outside radially outward in the radial direction C. The second return vane 54 is provided in the final stage partial casing 50c.

[0032] As shown in Figure 5, a volute flow path 60 is defined between the outer surface 52 of the peripheral wall 51 and the inner surface 11 of the outer casing body 25 of the outer casing 10, connecting the opening 55 of the peripheral wall 51 and the discharge port 13 of the outer casing 10. The volute flow path 60 is a flow path that extends around the peripheral wall 51 when viewed along the axial direction A. The flow path area of ​​the volute flow path 60 increases from the upstream side to the downstream side in the direction of liquid flow. In this specification, "flow path area" means the cross-sectional area of ​​the flow path in question at a cross-section perpendicular to its direction of extension.

[0033] As the three impellers 40 rotate in the circumferential direction B, the liquid is drawn into the internal space 10a through the suction port 12. The liquid drawn in from the suction port 12 passes through the first stage impeller 40a, the first return vane 53, the middle stage impeller 40b, the second return vane 54, and the final stage impeller 40c in that order. The liquid discharged radially outward from the final stage impeller 40c passes through the opening 55, through the volute flow path 60, and is discharged to the outside from the discharge port 13.

[0034] In this way, pump 1 can discharge the liquid after it has passed through the volute channel 60. This improves the efficiency of pressure recovery of the liquid compared to when the liquid is discharged without passing it through the volute channel 60.

[0035] The following describes further features of pump 1.

[0036] As shown in Figure 5, etc., the internal casing 31 is positioned outside the radial direction C of the final stage impeller 40c and is equipped with guide vanes 70 that guide the liquid discharged from the final stage impeller 40c to the outside in the radial direction C in a direction inclined with respect to the radial direction C (hereinafter simply referred to as the "inclined direction"). In this embodiment, the inclined direction is inclined with respect to the radial direction C and is along a plane perpendicular to the axial direction A. In other words, the inclined direction in this embodiment is inclined in the circumferential direction B with respect to the radial direction C. With such guide vanes 70, the liquid can be rectified before flowing into the volute flow path 60. This further improves the efficiency of liquid pressure recovery.

[0037] As shown in Figure 5, multiple guide vanes 70 (eight in this embodiment) are arranged at intervals in the circumferential direction B. As shown in Figure 6, two adjacent guide vanes 70 in the circumferential direction B, in a plan view perpendicular to the axial direction A, demarcate a guide channel 71 (the area shown by the dashed line in Figure 6) that extends along the inclination direction, between them in a direction perpendicular to the inclination direction (hereinafter simply referred to as the "orthogonal direction"). The channel area of ​​the guide channel 71 increases from the upstream side to the downstream side in the liquid flow direction (see the white arrow in Figure 6). With such a guide channel 71, the liquid pressure can be restored not only by the volute channel 60 but also by the guide channel 71. This further improves the efficiency of liquid pressure restoration.

[0038] In this embodiment, the guide channel 71 has a width W (length of the guide channel 71 in the direction perpendicular to the liquid flow direction) that increases as the flow path area increases from the upstream side to the downstream side in the liquid flow direction.

[0039] As shown in Figure 3, the guide vanes 70 are formed on the peripheral wall 51. This simplifies the structure of the pump 1 and makes it easier to miniaturize the pump 1 compared to the case where the guide vanes are provided separately from the peripheral wall 51 (for example, when the guide vanes are provided on the inside of the peripheral wall 51 in the radial direction C).

[0040] Furthermore, the guide vane 70 also serves as a connecting column that connects the portion of the peripheral wall 51 located at the tip side A1 of the opening 55 (hereinafter simply referred to as the "tip side") and the portion located at the base side A2 of the opening 55 (hereinafter simply referred to as the "base side"). This reduces the need to provide an element to connect the tip side and the base side separately from the guide vane 70, making it easier to simplify the structure of the peripheral wall 51. In this embodiment, the tip side includes the first connecting portion 75, the middle peripheral wall portion 51b, and the first peripheral wall portion 51a of the final stage peripheral wall portion 51c, which will be described later. In addition, the base side of this embodiment includes the second connecting portion 76 of the final stage peripheral wall portion 51c, which will be described later.

[0041] As shown in Figures 5 and 6, the opening 55 in this embodiment is partitioned between two adjacent guide vanes 70 in the circumferential direction B. The opening 55 in this embodiment also includes a guide channel 71.

[0042] Figure 7 is a perspective view showing the final stage casing 50c alone. As shown in Figure 7, the guide vane 70 is formed on the final stage peripheral wall portion 51c of the final stage casing 50c. The final stage peripheral wall portion 51c also includes a cylindrical first connecting portion 75 to which the middle stage casing 50b is connected at the tip end A1, and a cylindrical second connecting portion 76 to which the cover body 29 is connected at the base end A2. The guide vane 70 is integrally molded with the first connecting portion 75 and the second connecting portion 76 so as to connect the first connecting portion 75 and the second connecting portion 76 in the axial direction A. This structure improves the strength of the guide vane 70 and suppresses damage to the guide vane 70.

[0043] As shown in Figure 3, the first stage impeller 40a does not have guide vanes on its radially C-outward side to guide the liquid discharged from the first stage impeller 40a to the radially C-outward side. Similarly, the middle stage impeller 40b does not have guide vanes on its radially C-outward side to guide the liquid discharged from the middle stage impeller 40b to the radially C-outward side. In other words, the impeller 40 located at the tip A1 of the three impellers 40 (hereinafter sometimes referred to as the "tip-side impeller 40") does not have guide vanes on its radially C-outward side to guide the liquid discharged from the tip-side impeller 40. In conventional pumps, it was common to provide guide vanes not only on the final stage impeller but also on the radially outer side of the tip-side impeller in order to efficiently restore the pressure of the liquid. Therefore, in conventional pumps, it is necessary to provide guide vanes between, for example, the peripheral wall of the internal casing and the tip-side impeller, which results in an increase in the outer diameter of the peripheral wall of the internal casing, making it easier for the pump to become larger. In contrast, in pump 1, the efficiency of liquid pressure recovery can be improved by the volute flow path 60, so there is little need to provide guide vanes on the outside of the tip-side impeller 40 in the radial direction C. Therefore, as described above, a configuration without guide vanes on the outside of the tip-side impeller 40 in the radial direction C can be realized, and as a result, pump 1 can be made smaller.

[0044] The volute channel 60 in this embodiment extends along a plane perpendicular to the axial direction A. The width of the volute channel 60 in this embodiment increases from the upstream side to the downstream side in the direction of liquid flow (the length of the volute channel 60 in the direction perpendicular to its extension direction in a plan view perpendicular to the axial direction A). The volute channel 60 in this embodiment extends in a range that does not extend over the entire circumference of the circumferential direction B.

[0045] As shown in Figure 5, the blades 41 and discharge port 13 of the final stage impeller 40c are arranged on the same plane perpendicular to the axial direction A. This arrangement suppresses the increase in liquid pressure loss that occurs as the liquid discharged from the final stage impeller 40c reaches the discharge port 13, thereby suppressing a decrease in the pump efficiency of the pump 1. In this specification, "arranged on the same plane" means that there is at least one coplanar plane on which multiple elements overlap.

[0046] As shown in Figure 5, the blades 41 of the final stage impeller 40c, the volute flow path 60, and the discharge port 13 are arranged on the same plane perpendicular to the axial direction A. This arrangement further suppresses the increase in liquid pressure loss that occurs as the liquid discharged from the final stage impeller 40c reaches the discharge port 13, thereby further suppressing the decrease in the pump efficiency of the pump 1.

[0047] The pump relating to this disclosure is not limited to the specific configuration shown in the embodiments described above, and various modifications, changes, and combinations are possible as long as they do not deviate from the scope of the claims.

[0048] For example, in the embodiment described above, the pump 1 is equipped with three impellers 40, but it is not limited to this. The number of impellers equipped with the pump may be two, or four or more. Also, in the embodiment described above, all three impellers 40 are the same shape, but it is not limited to this. At least two of the impellers may have different shapes. Furthermore, there are no particular limitations on the number of guide vanes equipped with the internal casing, or the number of blades equipped with each of the multiple impellers. [Industrial applicability]

[0049] This disclosure relates to pumps. [Explanation of Symbols]

[0050] 1: Pump 10: External casing 10a: Internal space 11: Inner surface of the outer casing 12: Inlet 13:Discharge port 14: Attachment opening 18: Legs 20: Drive unit 21: Motor 22: Casing cover 23: Insertion part 25: External casing body 26: Shaft seal part 27: Sealing material 29: Cover body 30: Rotation axis 31: Internal casing 40: Impeller 40a: First stage impeller 40b: Middle impeller 40c: Final stage impeller 41: Wing section 50: Partial casing 50a: First stage casing 50b: Middle section casing 50c: Final stage casing 51: Peripheral wall 51a: First stage surrounding wall part 51b: Middle peripheral wall part 51c: Final stage peripheral wall part 52: Outer surface of the surrounding wall 53: First return feather 54: Second return feather 55:Aperture 60: Volute channel 70: Guide vane 71: Guide channel 75: First connection section 76: Second connection section A: Axis A1: Tip A2: Proximal side B: Circumferential direction C: Radial direction O: Central axis W: Width

Claims

1. It is a back-pull-out type pump, An external casing that separates the internal space from the suction port, discharge port, and mounting port connected to the internal space, The drive body comprises an insertion portion that can be inserted into and removed from the internal space through the aforementioned mounting opening, The aforementioned insertion portion is The axis of rotation and A plurality of impellers are attached to the aforementioned rotating shaft and arranged at intervals in the axial direction of the rotating shaft, The system comprises an internal casing having a peripheral wall surrounding the plurality of impellers in the radial direction of the rotation axis, Of any two of the plurality of impellers, the impeller located on the axial base end side is located downstream in the direction of the liquid flowing through the internal space compared to the impeller located on the axial tip side. The peripheral wall defines an opening that allows the liquid discharged radially outward from the final stage impeller, which is the impeller located furthest towards the base end among the plurality of impellers, to pass from the radially inside to the outside. A pump wherein a volute flow path connecting the opening and the discharge port is partitioned between the outer surface of the peripheral wall and the inner surface of the outer casing.

2. The pump according to claim 1, wherein the internal casing is positioned radially outside the final stage impeller and includes guide vanes that guide the liquid discharged radially outward from the final stage impeller in an inclined direction with respect to the radial direction.

3. Multiple guide vanes are arranged at intervals in the circumferential direction of the rotation axis. Of the plurality of guide vanes, two guide vanes adjacent to each other in the circumferential direction define a guide channel between them that extends along the inclined direction. The pump according to claim 2, wherein the flow channel area of ​​the guide channel increases from the upstream side to the downstream side in the flow direction.

4. The aforementioned guide vane is, Formed on the peripheral wall, The pump according to claim 2 or 3, wherein the peripheral wall also serves as a connecting column connecting a portion located on the tip side of the opening and a portion located on the base side of the opening.

5. The pump according to claim 2 or 3, wherein guide vanes are not provided on the radially outer side of the impeller located on the tip side of the final stage impeller among the plurality of impellers.

6. The pump according to any one of claims 1 to 3, wherein the blade portion of the final stage impeller and the discharge port are arranged on the same plane perpendicular to the axial direction.

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