JP2003120590A - Double suction pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double suction pump with a minimized loss capable of minimizing the circumferential deviation of flow rate. SOLUTION: This double suction pump comprises a first casing provided with an inlet port; a second casing provided with a delivery port, the second casing communicating with the first casing and being provided within the first casing; an impeller provided in the center of the second casing and mounted on a spindle; first and second passages branched by the outer wall of the second casing within the first casing and extended to the impeller along the outer wall of the second casing; and a straightening member provided on the upper stream to the flow of a fluid over the first and second passages within the first casing. A partitioning member for partitioning the first and second passages is shifted to one side from the center of the inlet port by 3-5% of the width of the intake port. The section of the partitioning member is formed in an outwardly protruding trapezoidal shape, and the farthest part of the passage is protruded outwardly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double suction pump having a spiral casing.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view of a conventional double-suction pump as disclosed in Japanese Patent Laid-Open No. 11-303789.
Further, FIG. 6 is a sectional view of the double suction pump shown in FIG. Such a double suction pump 100 has a first casing 300 and a second casing 200 arranged in the first casing.
00 and 300 communicate with each other. As can be seen from FIGS. 5 and 6, the first casing 300 has a suction port 35.
The second casing 200 has a discharge port 25.
It has 0. Further, an impeller 500 attached to a main shaft 400 rotatably provided so as to penetrate the first and second casings is arranged in the second casing 200. As can be seen from FIG. 5 and FIG. 6, the impeller 50 is passed from the vicinity of the suction port 350 of the first casing 300.
First and second channels 710, 72 extending to both sides of 0
0 is the first casing 300 and the second casing 200
It is formed between and. As shown in these drawings, the flow path extending from the suction port 350 branches from the outer portion 240 of the second casing 200 adjacent to the suction port 350 to the first and second flow paths 710 and 720. ..

As shown in FIG. 5, a partition plate 600 is provided between the first casing 300 and the second casing 200. The partition plate 600 extends from the outer portion 240 in FIG. 5 to the impeller 500. Although only one partition plate 600 is shown in FIG. 6, actually, two partition plates 600 are provided on both sides of the impeller 500 as shown in FIG. As shown in FIG. 6, the partition plate 600 extends in the radial direction of the main axis and parallel to the flow paths at the centers of the first and second flow paths, that is, on the center lines of the suction ports. With these partition plates 600, the first flow path 710 causes the third and fourth flow paths 730 and 740.
And the second flow path 720 is divided into fifth and sixth flow paths 750 and 760 (not shown), respectively.

The third and fourth flow paths will be described below, but the same applies to the fifth and sixth flow paths. FIG. 7A is a cross-sectional view of the third and fourth flow paths partitioned by the partition plate 600 at the outer end 610 of the partition plate 600. Further, FIG. 7B is a cross-sectional view of the third and fourth flow paths partitioned by the partition plate 600 at the inner end 620 of the partition plate 600. As shown in FIGS. 7 (a) and 7 (b), the cross sections of the third and fourth flow paths are substantially equal at the outer end 610 of the partition plate 600, but inside of the partition plate 600. At the side end portion 620, the cross-sectional area of the fourth flow passage 740 is larger than the cross-sectional area of the third flow passage 730. In addition, as shown by the dotted line in FIG. 7A, the flow rate of the fluid is large in the region inside the third and fourth flow passages 730 and 740 and adjacent to the partition plate.

In operation, the fluid sucked from the suction port 350 is supplied to the first casing 300 and the second casing 20.
0 and the first and second flow paths 710, 7 formed between
It flows through 20 to the impeller 500. Then, the fluid flowing out from the impeller 500 is discharged from the discharge port 250 through the spiral flow passage formed in the second casing 200.

[0006]

However, since these flow paths have the shapes as described above,
The flow rate of the fluid flowing into the impeller 500 is larger on the proximal side than the main shaft 400 from the suction port 350, and is small.
It becomes smaller from 0 on the distal side of the main shaft 400, and the flow amount is deviated in the circumferential direction around the impeller 500. Also,
As shown in FIG. 5, the first and second flow paths 710, 72 located distally of the main shaft 400 from the suction port 350.
Spindle portion 810 of the inner surface of the distal portion 800 of 0.
At an angle of about 40 ° with respect to the main axis 400, and the cross-sectional area of the distal portion 800 is relatively small. Thus, the cross-sectional area of the distal portion 800 of the first and second flow channels 710, 720 is
It is smaller than the cross-sectional area of the portion of 10, 720 proximal to the main axis 400. First and second flow paths 710, 720
Due to such a shape, the flow rate of the fluid flowing into the impeller 500 is larger near the main shaft 400 near the distal end and smaller than the main shaft 400 near the distal end. Therefore, this also causes a deviation in the flow rate in the circumferential direction around the impeller 500. Such circumferential deviation reduces pump efficiency and causes cavitation, which may cause noise and vibration. Therefore, it is preferable to eliminate such a bias in the circumferential direction and allow the fluid to flow into the impeller 500 substantially evenly in the circumferential direction.

Further, the both suction pumps 1 from the suction port 350.
Since the fluid sucked into 00 directly collides with the outer portion 240 of the outer wall of the second casing 200, loss occurs in this outer portion 240 and pump efficiency is reduced. Therefore, it is desirable to form a pump with less loss due to such collisions.

Therefore, it is an object of the present invention to provide a double suction pump that reduces the loss due to collision during operation and does not deviate the flow rate of the fluid flowing into the impeller in the circumferential direction.

[0009]

In order to achieve the above-mentioned object, according to the invention as set forth in claim 1, a first casing having a suction port, and a first casing which is circulated in the first casing A second casing arranged in one casing and provided with a discharge port; an impeller provided in the center of the second casing and attached to the main shaft; and a second casing in the first casing. First and second flow paths that are branched by the outer wall of the second casing and extend along the outer wall of the second casing to the impeller; and the first and second flows in the first casing. A double suction pump is provided, which comprises a rectifying member that is provided upstream of a flow path of a fluid.

That is, according to the invention of claim 1,
Since the fluid does not directly collide with the outer wall of the second casing, it is possible to reduce the loss in the vicinity of the suction ports of both suction pumps, especially in the outer portion of the second casing, and consequently improve the pump efficiency. You can

According to the second aspect of the present invention, the rectifying member is a triangular prism type rectifying member integrally formed with the second casing, and the rectifying member is provided with respect to the partition member and the main shaft. And extends vertically, and one apex in the cross section of the rectifying member faces the suction port. That is, according to the invention described in claim 2, it is possible to easily flow the fluid through the first and second flow paths while significantly reducing the loss. When the straightening member is formed integrally with the casing, the straightening member can be formed easily and at low cost.

According to the third aspect of the present invention, there is provided a first casing having a suction port, and a discharge port which is disposed in the first casing and which is circulated in the first casing. A second casing, an impeller provided at the center of the second casing and attached to the main shaft, and a second casing that is branched by an outer wall of the second casing in the first casing. First and second flow passages extending to the impeller along the outer wall of the casing, and a main shaft of inner surfaces of the first and second flow passages located on the distal side of the main shaft from the suction port. A double suction pump is provided, the side portions of which form an angle of 0 ° to 40 ° with respect to the main axis.

That is, according to the invention of claim 3,
Since the cross-sectional area of the flow path located on the distal side of the main shaft from the suction port increases, a large amount of fluid can be supplied to the flow path on the distal side from the suction port, and the circumferential direction of the fluid flowing into the impeller The bias of can be reduced. This can prevent cavitation from occurring and reduce noise and vibration.

According to the invention described in claim 4, there is provided a first casing having a suction port, and a discharge port which is disposed in the first casing and is distributed in the first casing. A second casing, an impeller provided at the center of the second casing and attached to the main shaft, and a second casing that is branched by an outer wall of the second casing in the first casing. First and second flow passages extending to the impeller along the outer wall of the casing, the first and second flow passages are respectively third and fourth flow passages, and fifth and sixth flow passages. For partitioning into two partition members provided between the inner wall of the first casing and the outer wall of the second casing, the partition members from the center of the suction port to the fourth flow. Road and the sixth stream Double-suction pump is provided which are offset by 3% to 5% of the respective width of the suction port toward the.

That is, according to the invention of claim 4,
Since it is possible to increase the cross-sectional area of the flow path located on the distal side of the main shaft from the suction port, a large amount of fluid can be supplied to the flow path on the distal side from the suction port, and The deviation of the inflowing fluid in the circumferential direction can be reduced. This can prevent cavitation from occurring and reduce noise and vibration.

According to the fifth aspect of the present invention, the farthest portion of the first casing located farthest from the center of the impeller in the cross section of the third to sixth flow passages is directed outward. In addition to projecting, the partition member has a trapezoidal cross section that is convex outward.

That is, according to the invention of claim 5,
Since the difference in flow rate between the two flow paths can be reduced by reducing the area where the flow rate is large in the cross-sectional area of the flow path, the circumferential deviation of the fluid flowing into the impeller can be further reduced. This can prevent the occurrence of cavitation and further reduce noise and vibration.

[0018]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are designated by the same reference numerals. The scales of these drawings are appropriately changed to facilitate understanding. FIG. 1 is an axial sectional view of a double-suction pump according to a first embodiment of the present invention. FIG. 2 is a sectional view of the double suction pump of the present invention. Similar to the double-suction pump 100 described in the related art, the double-suction pump 10 of the present invention includes the first casing 3
0 and a second casing 20 arranged in this first casing.
Are in communication with each other. As can be seen from FIGS. 1 and 2, the first casing 30 has a suction port 35,
The second casing 20 has a discharge port 25. Further, an impeller 50 mounted on a main shaft 40 rotatably provided so as to penetrate the first and second casings is arranged in the second casing 20. As can be seen from FIGS. 1 and 2, the suction port 3 of the first casing 30.
First and second flow paths 71, 72 extending from around 5 to both sides of the impeller 50 are formed between the first casing 30 and the second casing 20. As shown in these drawings, the flow path extending from the suction port 35 is
From the outer part 24 of the second casing 20 adjacent to the first and second flow paths 71 and 72.

As shown in FIG. 1, a partition plate 60 is provided between the first casing 30 and the second casing 20. These partition plates 60 extend from the outer portion 24 in FIG. 1 to the impeller 50. Although only one partition plate 60 is shown in FIG. 2, actually two partition plates 60 are provided on both sides of the impeller 50 as shown in FIG. As shown in FIG. 2, the partition plate 60 extends in the radial direction of the main axis and parallel to the first and second flow paths, that is, on the center line of the suction port, in parallel with these flow paths. With these partition plates 600, the first flow path 71 becomes the third and fourth flow paths 73 and 74, and the second flow path 7
2 is divided into fifth and sixth flow paths 75 and 76 (not shown), respectively.

In operation, the fluid sucked from the suction port 35 passes through the first and second flow passages 71 and 72 formed between the first casing 30 and the second casing 20, and the impeller. Flows up to 50. Then, the fluid flowing out from the impeller 50 is discharged from the discharge port 25 through the spiral flow passage formed in the second casing 20.

In the first embodiment of the present invention, the double suction pump 10 is provided with the rectifying member 90 on the outer portion 24 of the second casing 20 adjacent to the suction port 35.
As can be seen from FIGS. 1 and 2, the rectifying member 90 includes the main shaft 40 and the partition plate 60 upstream from the fluid flow.
It is arranged so as to traverse the suction port 35 almost perpendicularly to and. The flow straightening member 90 allows the fluid sucked from the suction port 35 to easily flow toward both sides of the impeller 50 without directly colliding with the outer portion 24 of the second casing 20. Casing 2
The loss in the 0 outer part 24 can be significantly reduced. This can improve the efficiency of the entire pump.

The rectifying member 90 in the present invention is a solid substantially triangular prism member, and is preferably formed integrally with the second casing 20. Thereby, the rectifying member can be formed easily and at low cost while easily reducing the loss. Furthermore, the rectifying member 90 may be a plate-shaped member that allows the fluid to easily flow through the first and second flow paths 71 and 72, and in this case, the fluid is also outside the second casing 20. Since it is possible to prevent the collision with the portion 24 directly, the loss can be significantly reduced.

FIG. 3 is an enlarged view of a double suction pump according to the second embodiment of the present invention. In FIG. 3, a cross section of the distal side portion 80 located far from the suction port 35 in the first flow path 71 is shown. The spindle-side portion 81 of the inner surface of the distal-side portion 80 is the spindle-side portion 8 of the inner surface of the distal-side portion 800 in the double-suction pump of the related art.
It is formed further inward than 10, that is, closer to the main shaft 40. In the prior art, the spindle 400
Angle A formed by the main shaft side portion 810 of the distal side portion 800
0 is about 40 °, but in the present embodiment, the spindle 40
The angle A1 formed by the main shaft side portion 81 of the distal side portion 80 is smaller than this, and in the embodiment shown in FIG. 3, the angle A1 is about 10 °. By forming the distal portion 80 of the first and second flow paths 71, 72 in such a shape, a large amount of fluid can also flow in the distal portion 80. Therefore, the flow rate difference between the proximal side and the distal side around the impeller can be reduced, and as a result, the circumferential deviation of the flow rate of the fluid flowing into the impeller 50 can be reduced. Therefore, it is possible to prevent the occurrence of cavitation and reduce noise and vibration.

The main shaft side portion 81 of the first and second flow paths 71, 72 may include a plane parallel to the main shaft 40, and in this case, from the suction port 35 to the flow path on the distal side. Since a larger amount of fluid can be flowed, the fluid is impeller 50
It is possible to allow the gas to flow in the circumferential direction substantially evenly. Therefore, the deviation in the circumferential direction of the fluid around the impeller 50 can be further reduced. In FIG. 3, the angle A1 formed by the main shaft 40 and the main shaft side portion 81 is about 10 °, but this angle A1 is larger than 0 ° and is 40 °.
It suffices that the angle is smaller than 0 °, and even in such a case, a large amount of fluid can flow in the distal side flow path.

4 (a) and 4 (b) are partially enlarged sectional views showing the flow paths of the double suction pumps according to the third and fourth embodiments of the present invention. In these drawings, the partition plate 6
The third and fourth flow paths 73, 74 partitioned by the partition plate 60 are shown in the vicinity of the inner end portion 62 of 0. Actually, the fifth and sixth flow paths 75 and 76 have the same structure, but only the third and fourth flow paths 73 and 74 will be described for easy understanding.

In the above-mentioned conventional technique, the partition plate 600 in the first casing 300 is positioned in the radial direction of the impeller 500 and on the center line of the suction port 350. However, the third plate shown in FIG. In the above embodiment, the partition plate 60 is arranged parallel to the radial direction of the impeller 50 and shifted from the center line of the suction port 350 toward the fourth flow path 74. In the present embodiment, the partition plate 60 is about 3% to about 5% of the width of the suction port 35 from the center of the suction port 35, and about 4% in the embodiment shown in FIG.
Only offset toward the fourth flow path 74. As a result, the internal volumes of the entire third and fourth flow paths 73, 74 become substantially equal. Therefore, a larger amount of fluid than before flows from the suction port 35 to the distal side of the main shaft 40,
The flow rate of the fluid flowing into the impeller is reduced between the distal side and the proximal side of the impeller 50. Therefore, the fluid can be flown around the impeller 50 substantially evenly in the circumferential direction. By thus reducing the deviation in the circumferential direction of the fluid flowing into the impeller 50, it is possible to prevent the occurrence of cavitation and reduce noise and vibration.

Next, in the fourth embodiment of the present invention shown in FIG. 4 (b), the position of the partition plate is shifted toward the fourth flow path by about 3% to about 5%, and the partition plate 60 is moved. The cross section has a trapezoidal shape that is convex outward. As described above, the flow rate of the fluid is the inner side of the cross section of these flow paths and the partition plate 6
Although it is large in the region adjacent to 0, in this embodiment, a part of the partition plate is located in the region where the flow rate is the largest. Further, in this embodiment, in order to secure the cross-sectional area of the flow path, the farthest portion of the flow path located on the inner side in the cross section of the flow path and farthest from the region adjacent to the partition plate 60 is outward. Is projected toward. This protruding portion is located farthest from the center of the impeller.

By forming the flow passage in such a shape, the region of the flow passage having the largest flow rate moves in the direction away from the impeller, and the variation of the flow distribution in the two flow passages is reduced. Therefore, a larger amount of fluid than the conventional one flows from the suction port 35 to the distal side of the main shaft 40, and the flow rate of the fluid flowing into the impeller varies between the distal side and the proximal side of the impeller 50. Is less. Therefore, the fluid can be flown around the impeller 50 substantially evenly in the circumferential direction. By thus reducing the deviation in the circumferential direction of the fluid flowing into the impeller 50, it is possible to prevent the occurrence of cavitation and reduce noise and vibration.

As a matter of course, the deviation of the flow rate of the fluid flowing into the impeller in the circumferential direction can be reduced by only making the cross section of the partition plate trapezoidal without projecting the farthest portion to the outside. can do. Further, a double suction pump combining some of the first to fourth embodiments described above is included in the scope of the present invention.

[0030]

According to the first aspect of the present invention, the loss in the vicinity of the suction ports of both suction pumps can be reduced, and as a result, the pump efficiency can be improved.

Further, according to the invention of claim 2,
The fluid can be easily passed through the first and second flow paths while significantly reducing the loss, and when the straightening member is integrally formed with the casing, the straightening member can be formed easily and at low cost. The effect that it is possible can be produced.

Further, according to the invention of claim 3,
It is possible to reduce the deviation in the circumferential direction of the fluid flowing into the impeller, which can prevent the occurrence of cavitation and reduce noise and vibration.

Further, according to the invention of claim 4,
It is possible to reduce the deviation in the circumferential direction of the fluid flowing into the impeller, which can prevent the occurrence of cavitation and reduce noise and vibration.

Further, according to the invention of claim 5,
It is possible to further reduce the deviation in the circumferential direction of the fluid flowing into the impeller, which can prevent the occurrence of cavitation and further reduce noise and vibration.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a double-suction pump of the present invention.

FIG. 2 is a sectional view of a double suction pump of the present invention.

FIG. 3 is an enlarged view of a double suction pump according to a second embodiment of the present invention.

FIG. 4 (a) is a partially enlarged cross-sectional view showing a flow path of a double-suction pump according to a third embodiment of the present invention. (B) It is a partial expanded sectional view which shows the flow path of the double suction pump based on 4th Embodiment of this invention.

FIG. 5 is a sectional view in the axial direction of a double-suction pump according to the related art.

FIG. 6 is a sectional view of a double-suction pump according to the related art.

FIG. 7 (a) is a partial enlarged view showing a flow path at an outer end of a partition plate of a double-suction pump according to a conventional technique. (B) It is the elements on larger scale which shows the flow path in the inner side edge part of the partition plate of the double suction pump in a prior art.

[Explanation of symbols]

10 ... Double suction pump 20 ... Second casing 24 ... Outer part 25 ... Discharge port 30 ... First casing 35 ... Suction port 40 ... Spindle 50 ... Impeller 60 ... Partition board 62 ... Inner end 71 ... First flow path 72 ... second flow path 73 ... Third flow path 74 ... Fourth channel 75 ... Fifth channel 80 ... Distal part 90 ... rectifying member

Claims (5)

[Claims] 1. A first casing having a suction port, a second casing which is in circulation in the first casing and is provided in the first casing, and has a discharge port, and the second casing. An impeller provided at the center of the casing and attached to the main shaft, and an impeller that is branched in the first casing by an outer wall of the second casing and extends along the outer wall of the second casing. Both suction pumps having first and second flow paths extending up to and a rectifying member provided upstream of the first and second flow paths in the first casing with respect to the flow of fluid. . 2. The rectifying member is a triangular prism type rectifying member integrally formed with the second casing, the rectifying member extending perpendicularly to the partition member and the main shaft, The double suction pump according to claim 1, wherein one apex of the cross section of the member faces the suction port. 3. A first casing having a suction port, a second casing which is disposed in the first casing and which is provided with a discharge port and which is in communication with the first casing, and the second casing. An impeller provided at the center of the casing and attached to the main shaft, and an impeller that is branched in the first casing by an outer wall of the second casing and extends along the outer wall of the second casing. The first and second flow paths extending to the main shaft, and the main shaft side portion of the inner surface of the first and second flow paths located on the distal side of the main shaft from the suction port is 0 with respect to the main shaft. Double suction pump with an angle of 40 ° from 40 °. 4. A first casing having a suction port, a second casing which is in circulation in the first casing and is provided in the first casing, and has a discharge port, and the second casing. An impeller provided at the center of the casing and attached to the main shaft, and an impeller that is branched in the first casing by an outer wall of the second casing and extends along the outer wall of the second casing. First and second flow paths extending to, and the first casing for partitioning the first and second flow paths into third and fourth flow paths and fifth and sixth flow paths, respectively. And two partitioning members provided between the inner wall of the second casing and the outer wall of the second casing, the partitioning members from the center of the suction port to the fourth flow path and the sixth flow path. Width of the suction port Double suction pump 3% are shifted respectively by 5%. 5. The farthest part of the first casing located farthest from the center of the impeller in the cross sections of the third to sixth flow paths is projected outward and the cross section of the partition member is The double suction pump according to claim 4, which has a trapezoidal shape that is convex outward.