JP2007291862A - Double suction centrifugal pump, impeller thereof, and manufacturing method of impeller - Google Patents

Abstract

An object of the present invention is to achieve both the workability and processing accuracy of an impeller used in a double suction centrifugal pump.
A double suction centrifugal pump 50 accommodates a rotary shaft 1, a double suction type centrifugal impeller 2 attached to the rotary shaft, and a double suction type centrifugal impeller. And a casing 3 having a spiral casing. Both suction type centrifugal impellers have a pair of single suction centrifugal impellers 2e and 2f formed on a mirror surface and a disk-like member 2c disposed between the single suction centrifugal impellers. The single suction centrifugal impeller has a side plate 2b, a plurality of blades 2d extending to substantially the same outer diameter as the side plate, and a main plate 2a having a smaller diameter than the side plate.
[Selection] Figure 1

Description

  The present invention relates to a double suction centrifugal pump, an impeller provided therein, and a manufacturing method thereof.

  Examples of conventional double suction centrifugal pumps are described in Patent Document 1 and Patent Document 2. In the double suction centrifugal pump described in Patent Document 1, in order to stabilize the thrust force of the pump and widen the stable operation range of the pump, a pressure equalizing communication hole is provided in the partition wall separating the suction ports in the horizontal direction. Yes. By this communication hole, generation of differential pressure on both sides of the partition wall is suppressed, and the main shaft is prevented from swinging.

  Moreover, in the both suction pumps of patent document 2, in order to reduce pressure pulsation, the partition plate is provided in the inside of the volute casing which has several volute flow paths. Wings are arranged at equal pitches on both sides of the partition plate, and the impeller having the blades is housed in the volute casing. Further, the suction casing guides the fluid to the wings on both sides partitioned by the partition plate. The blades on both sides of the impeller partition plate are out of phase, and when the tip of the blade on one side is at the winding start end of the volute, the tip of any blade on the other side It is in a different position from the starting end.

Japanese Patent Laid-Open No. 11-303789 JP 2002-133891 A

  In the double suction centrifugal pumps described in Patent Documents 1 and 2, the impeller is often manufactured by integral casting unless the blade shape is extremely simple and can be machined. Thus, when manufacturing an impeller by integral casting, the wooden structure required for casting becomes complicated, and there exists a possibility that the circumference | surroundings of hot water may not become smooth and may cause a casting defect. Moreover, since it is difficult to obtain a predetermined impeller shape as it is as cast, the blade surface is formed by hand finishing with reference to a gauge formed in a predetermined shape. This hand-finishing requires skill to maintain accuracy, and hand-finishing requires significantly more processing steps than machining.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to reduce the number of man-hours for processing the impeller used in the double suction centrifugal pump. Another object of the present invention is to improve the machining accuracy of an impeller used for both suction centrifugal pumps. Still another object of the present invention is to realize a double suction centrifugal pump that is less prone to casting defects.

  A feature of the present invention that achieves the above-described object is that a rotary shaft, a double-suction centrifugal impeller attached to the rotary shaft, and a suction spiral casing and a discharge spiral casing that accommodate the double-suction centrifugal impeller In the double-suction centrifugal pump having a casing having a double-suction centrifugal impeller, a double-suction centrifugal impeller is a pair of single-suction centrifugal impellers formed on a mirror surface, and a disk-like shape disposed between the single-suction centrifugal impellers The single suction centrifugal impeller has a side plate, a plurality of blades extending to substantially the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate.

  And in this feature, it has a pair of sleeves arranged on both sides of a double suction type centrifugal impeller attached to the rotating shaft and means for fixing the sleeve, and this sleeve fixing means is screwed onto the rotating shaft. Preferably, the circumferential positions of the blades of the pair of single suction centrifugal impellers may be changed to face each other.

  Another feature of the present invention that achieves the above object is a double-suction centrifugal impeller that is sucked from both sides in the axial direction and discharged in the radial direction. The single suction centrifugal impeller includes a side plate, a plurality of blades extending to the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate. And the circumferential direction position of the blade | wing of a pair of single suction centrifugal impeller is changed mutually, and it is made to face back.

  And in this feature, a plurality of through holes may be formed in the disk-shaped member, and the plurality of through holes may be formed between the blades of the pair of single suction centrifugal impellers. A straightening blade narrower than the outlet width of the single suction impeller may be provided, and the straightening blade may be positioned between the blades of the single suction impeller. Moreover, you may form a some groove | channel in a disk-shaped member, and may fit the edge part of the some blade | wing which a single suction impeller has in this groove | channel.

  Still another feature of the present invention that achieves the above-described object is that it is a double-suction centrifugal impeller that sucks from both sides in the axial direction and discharges in the radial direction. The single suction centrifugal impeller includes a side plate, a plurality of blades extending to substantially the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate. It has a pair of single-suction centrifugal impellers whose circumferential positions of the blades are aligned with each other and face each other.

  Still another feature of the present invention that achieves the above object is that a pair of single-suction centrifugal impeller members having a main plate outer diameter smaller than a side plate outer diameter are formed on a mirror surface in a manufacturing method of an impeller used for both suction centrifugal pumps. After this, this single suction centrifugal impeller is made to face the back via a disk-shaped member, and the circumferential phase of the blades of the pair of single suction centrifugal impellers is changed with respect to each other. In this feature, a plurality of rectifying blades having a blade height lower than the plurality of blades forming the single suction impeller may be formed on the outer diameter side of the main plate outer diameter of the disk-shaped member.

  According to the present invention, the impeller used for both suction centrifugal pumps is configured such that the main plate and the side plate with the outer diameter side notched are opposed to each other, and the single suction impeller composed of a plurality of blades is opposed to the back, and the opposed portion corresponds to the main plate. Since the ring is provided, it is only necessary to create a single suction impeller having a large number of openings, and the man-hours for processing the impeller can be reduced. Moreover, since the opening part increased and the narrow part reduced, use of a processing tool becomes easy and the processing precision of the impeller used for a double suction vortex pump improves. Furthermore, since the number of openings is increased in the impeller, the hot water around the casting is good and casting defects are less likely to occur. Furthermore, the circumferential position of the blades can be easily changed by the left and right impeller elements, and a low noise impeller can be realized.

  Hereinafter, some examples of the double suction centrifugal pump according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an impeller 2 used for both suction centrifugal pumps 50. FIG. 2 is a longitudinal sectional view of a double suction centrifugal pump 50 incorporating the impeller 2 shown in FIG. In the double suction centrifugal pump 50 of the present embodiment, the rotary shaft 1 is arranged in the horizontal direction. An impeller 2 which will be described in detail later is attached to a substantially central portion of the rotating shaft 1.

  Sleeves 5 are arranged on both sides in the axial direction of the impeller 2, and the sleeves 5 are fitted on the rotary shaft 1. A lock nut 6 is disposed at the end of the sleeve 5 on the side opposite to the impeller, and the lock nut 6 is screwed onto the rotary shaft 1 to fix the impeller 2 and the sleeve 5. A seal member such as a gland packing is disposed on the outer peripheral portion of the sleeve 5, and this seal member is held by the casing 3.

  A radial bearing and a thrust bearing for supporting the rotary shaft 1 in the radial direction and the thrust direction are attached to one end side of the rotary shaft 1 to form a bearing portion 4. A coupling is attached to the other end side of the rotating shaft 1, and the rotating shaft 1 is rotationally driven by being connected to a driving machine (not shown) via this coupling. Between the coupling and the lock nut 6, a bearing portion 4 including a radial bearing that supports the rotary shaft 1 in the radial direction is formed. The left and right bearing portions 4 have stationary portions that protrude from the casing 3.

  In the casing 3, a discharge spiral casing is formed in the central portion in the axial direction, and suction spiral casings are formed on both sides of the discharge spiral casing. The suction spiral casing has an opening at a portion facing the impeller 2, and the flow swirled by the suction spiral casing flows into the impeller 2.

  The impeller 2 has a shape in which the centrifugal impeller is opposed to the back surface, and the outer peripheral portion on the suction side prevents the flow in the discharge spiral casing from leaking into the suction spiral casing and recirculating. An impeller ring 8 is attached. A casing ring 7 is attached to the casing 3 so as to face the impeller ring 8. The impeller ring 8 and the casing ring 7 act as a seal.

  As shown in FIG. 1, the impeller 2 is a centrifugal impeller 2 that sucks fluid from the axial direction and discharges it in the radial direction, and includes a main plate 2 a that fits the rotary shaft 1 and a side plate 2 b that is positioned on the casing 3 side. And end portions connected to the main plate 2a and the side plate 2b, and a plurality of blades 2d arranged at substantially equal pitches in the circumferential direction. Here, in the impeller 3 of the present embodiment, the single suction centrifugal impellers 2e and 2f are opposed to each other with the ring 2c interposed therebetween.

That is, since the left impeller 2e and the right impeller 2f have different rotational directions, the direction of the vane 2d is a mirror shape, but is otherwise the same shape. Moreover, unlike the normal single suction impeller, the outer diameter position of the main plate 2a does not extend to the outer diameter position of the impellers 2e and 2f, but is smaller than the outer diameter of the impellers 2e and 2f. . On the back side of the main plate 2a of the left and right impellers 2e and 2f, a ring 2c having an outer diameter substantially equal to the outer diameter of the impellers 2e and 2f is sandwiched. The ring 2c is coupled to both the impellers 2e and 2f by pins 9, and acts as a main plate 2a.

  Here, in the both suction centrifugal pumps 50 of the present embodiment, both the in-phase impeller having the same circumferential position of the blades 2d of the left and right impellers 2e and 2f and the different-phase impeller having different circumferential positions are used. Can be used. If the in-phase impeller is used, the peak of vibration and noise due to the number of blades may increase. Therefore, if it is desired to reduce the vibration and noise of both suction centrifugal pumps 50 by pressure pulsation, use a different-phase impeller. . On the other hand, in the different phase impeller, the left and right flows having different flow states are mixed after leaving the impeller. Therefore, an in-phase impeller is used when performance is important.

  Next, the manufacturing method of the impeller 2 shown in the above embodiment will be described in detail below. Conventionally, when manufacturing the impeller 2, a wooden mold that represents the shape of the blade 2 d and the main plate 2 a and the side plate 2 b is manufactured and integrally cast using this wooden mold. Then, it is processed by hand finishing with reference to a gauge or the like indicating the shape of the blade 2d. However, in this method, when the exit width of the impeller 2 is narrow, particularly in the impeller 2 in which the main plate 2a is extended to the outer diameter portion of the impeller 2 in order to obtain a different-phase impeller, the processing tool is inserted to the flow path surface. It could be difficult.

  Therefore, in this embodiment, the main plate 2a has an open shape that does not extend to the outer periphery of the impellers 2e and 2f. In the case of a welded structure, the side plate member having the side plate 2b and the plurality of blades 2d is machined from the material of the side plate 2b by machining, and the main plate 2a having a trumpet surface is also machined by machining. Join by welding. On the other hand, in the case of a cast structure, the processing method itself is almost the same as that of the prior art, but since the main plate 2a side has an open structure, a hand-finished tool can be easily inserted to the flow path surface. In addition, depending on the blade shape, finishing can be performed by machining.

  In the single suction impellers 2e and 2f, the outer peripheral side of the main plate 2a does not extend to the impellers 2e and 2f but has an open shape. The main plate 2a, the side plate 2b, and the plurality of blades 2d thus formed are integrally formed by the above-described method. When finishing by machining in order to achieve the dimensional accuracy required for the impellers 2e and 2f, a machining tool such as a three-dimensional processing machine is inserted into the impellers 2e and 2f from the open shape portion without the main plate 2a. The flow path surrounded by the main plate 2a, the side plate 2b, and the blade 2d of the suction impellers 2e and 2f is processed. At this time, the processing tool can be inserted also from the suction side and the discharge side of the single suction impellers 2e and 2f.

  The impellers 2e and 2f thus created with the welded structure or the cast structure are opposed to each other with the ring 2c interposed therebetween. At that time, the main plate 2a and the ring 2c of the impellers 2e and 2f are coupled by the pin 9. The pin 9 transmits torque between the impellers 2e and 2f and the ring 2c. It is also used for circumferential positioning of the left and right impellers 2e and 2f. The shape of the impeller 2 is determined by the coupling position of the pin 9, whether it is formed in a different phase impeller or in the same phase impeller.

  After the two impellers 2e and 2f and the ring 2c are connected by the pin 9, the two impellers 2e and 2f are fixed using the bolts 13. In this embodiment, the impeller ring 8 is attached to the suction side of the impellers 2e and 2f. The impeller 2 fixed by the bolt 13 is inserted into the rotary shaft 1 and then fixed to the rotary shaft 1 by the sleeve 5 and the lock nut 6.

  When the impeller 2 is manufactured by integrating the left and right impellers 2e and 2f, if the mass becomes too large and handling becomes difficult, the impeller 2e, the ring 2c, and the impeller 2f are separately provided on the rotary shaft 1. What is necessary is just to set it as the impeller 2 inserted in order every time and integrated on the rotating shaft 1. FIG. A key groove 16 is formed in the rotary shaft 1 and each of the impellers 2 e and 2 f as a circumferential detent of the impeller 2, and a key 17 is fitted in the groove 16.

  According to the present embodiment, since the shape formation of the single suction impellers 2e and 2f is facilitated, casting defects can be reduced in the case of castings. Furthermore, in addition to the two directions on the suction side and the discharge side of the impellers 2e and 2f, machining from the direction of the main plate 2a on the conventional main plate 2a is possible, which facilitates machining and is applicable to machining. And the impeller 2 with high dimensional accuracy can be manufactured in a short time.

The right side suction impeller 2f is different in rotation direction from the left side suction impeller 2e and the blade 2d has a mirror image shape. Therefore, the production data (coordinate data) of the blade 2d of the left impeller 2e The production data of the right impeller 2e can be used simply by conversion. This facilitates processing and saves time and labor for data creation.

A ring 2c incorporated between the two impellers 2e and 2f is connected to the impeller 2e,
2f. In this embodiment, a simple disk-like shape is sufficient, so that the ring 2c can be easily manufactured by machining the rolled plate material with a lathe or the like. Therefore, the required thickness can be reduced as compared with the case of manufacturing with a conventional casting, and a highly accurate part with reduced casting defects can be obtained.

  Another embodiment of the impeller 2 according to the present invention will be described with reference to FIGS. FIG. 3 shows the in-phase impeller 2 in a longitudinal sectional view. The left and right impellers 2e and 2f are manufactured in the same manner as in the above embodiment, and are directly opposed to the back without using a ring. When the two impellers 2e and 2f are fastened, they are circumferentially positioned using pins. The suction side ring 2c is omitted. The circumferential positions of the blades 2d of the two single suction impellers 2e and 2f are combined to form an in-phase impeller. Since the flow paths of the left and right impellers 2e and 2f are in phase, a ring for separating the two impellers is not necessary. Thereby, the axial direction length of the impeller 2 can be shortened.

  FIG. 4 shows an example in which the communication hole 10 is formed in the ring 2c in the embodiment shown in FIG. The figure (a) is a longitudinal cross-sectional view of the impeller 2, and the figure (b) is a front view of the impeller 2f. The independent flow paths formed by the two piece suction impellers 2e and 2f are communicated with each other through the communication hole 10. According to this example, the pressure imbalance in the flow paths in the left and right impellers 2e and 2f can be alleviated, and the axial thrust applied to the impeller 2 can be reduced.

FIG. 5 is a longitudinal sectional view (FIG. 5 (a)) and a right side view (FIG. 5 (b)) of still another embodiment of the double suction impeller according to the present invention. Also in the present embodiment, the circumferential phases of the left and right impellers 2e and 2f are made different. This embodiment differs from the embodiment shown in FIG. 1 in that the left and right impellers 2e,
This is because the rectifying blades 11 are provided on the ring 2c arranged between 2f.

The rectifying blade 11 is attached to the ring 2c by welding. As shown in the side view (FIG. 5B), the number of the rectifying blades 11 is the same as the number of blades, and the circumferential position is substantially at the center between the blades 2d. The shape of the rectifying blade 11 is a two-dimensional blade that matches the shape of the main plate side end of the blade 2d. The height in the axial direction of the rectifying blade 11 is very small as compared with the exit width of the impeller 2, and extends in the radial direction from the exit side of the impeller 2 to the inner diameter side to the vicinity of the outer diameter end of the main plate 2a.

  According to the present embodiment, in the different-phase impeller 2, since the flow exiting the right impeller 2f and the left impeller 2e flows into the discharge spiral flow path with different phases, the flow exiting the impeller Can be made uniform, and peak values of vibration and noise can be reduced. Moreover, since the height of the rectifying blade is low, processing is also easy. In this embodiment, the rectifying blades are attached to the ring by welding, but it is of course possible to integrally process the ring 2c by machining or pressing.

  FIG. 6 is a longitudinal sectional view showing still another embodiment of the double suction impeller according to the present invention. Also in the present embodiment, the circumferential phases of the left and right impellers 2e and 2f are made different. This embodiment differs from the embodiment shown in FIG. 1 in that a blade mounting groove 12 for inserting the blade 2d into the ring 2c is formed. The ring 2c before attaching the blade | wing 2d to the figure (b) is shown with a front view.

  In the embodiment shown in FIG. 1, the blades 2d of the left and right impellers 2e, 2f are structured to be cantilevered only by the side plate 2b on the main plate side and the outer diameter side. In this embodiment, since the end of the blade 2d is fitted in the groove 12 formed in the ring 2c, the blade 2d has a both-end support shape. Thus, since the groove | channel 12 which the blade | wing 2d fits in the ring 2c was formed, the stress of the support part of the blade | wing 2d falls and the reliability of a blade | wing improves. Alternatively, the fluid force that causes the allowable limit stress of the blade 2b can be increased, and the height of the double suction vortex pump 50 can be increased.

  In each of the above embodiments, the blades of the impeller used for both suction centrifugal pumps are formed integrally with the side plate, but may be formed integrally with the main plate, and then the side plate side end may be fixed to the side plate. . Alternatively, all of the main plate, the blades, and the side plates may be integrally formed and then finished to a predetermined size. The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and design changes can be made without departing from the spirit of the present invention.

The longitudinal cross-sectional view of one Example of the impeller part used for the double suction vortex pump which concerns on this invention. The longitudinal cross-sectional view of one Example of the double suction vortex pump which has an impeller shown in FIG. The longitudinal cross-sectional view of the other Example of the impeller part used for the double suction vortex pump which concerns on this invention. The longitudinal cross-sectional view and side view (part) of other Example of the impeller part used for the both suction centrifugal pump which concerns on this invention. The longitudinal cross-sectional view and side view (part) of other Example of the impeller part used for the both suction centrifugal pump which concerns on this invention. The longitudinal cross-sectional view and side view (part) of other Example of the impeller part used for the both suction centrifugal pump which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotating shaft, 2 ... Impeller, 2a ... Main plate, 2b ... Side plate, 2c ... Ring (disk-shaped member),
2d ... blade, 2e, 2f ... single suction impeller, 3 ... casing, 4 ... bearing, 5 ... sleeve, 6 ... lock nut, 7 ... casing ring, 8 ... impeller ring, 9 ... pin, 10 ... communication hole, DESCRIPTION OF SYMBOLS 11 ... Commutation blade | wing, 12 ... Blade attachment groove | channel, 13 ... Bolt, 50 ... Both suction | inhalation vortex pump.

Claims (10)

A double-suction centrifugal pump comprising a rotary shaft, a double-suction centrifugal impeller attached to the rotary shaft, and a casing that houses the double-suction centrifugal impeller and has a suction spiral casing and a discharge spiral casing In
The double-suction centrifugal impeller has a pair of single-suction centrifugal impellers formed on a mirror surface and a disk-like member disposed between the single-suction centrifugal impellers, and the single-suction centrifugal impeller Has a side plate, a plurality of blades extending to substantially the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate.   A pair of sleeves disposed on both sides of a double-suction centrifugal impeller attached to the rotating shaft and means for fixing the sleeve; and the sleeve fixing means is screwed onto the rotating shaft. The double suction centrifugal pump according to claim 1, wherein the suction pump is a double suction pump.   The double suction centrifugal pump according to claim 1, wherein the circumferential positions of the pair of single suction centrifugal impellers are changed from each other so as to face each other.   In a double suction centrifugal impeller that sucks in from both sides in the axial direction and discharges in the radial direction, a pair of single suction centrifugal impellers formed on a mirror surface and a disk-shaped member disposed between the single suction centrifugal impellers The single suction centrifugal impeller includes a side plate, a plurality of blades extending to substantially the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate. An impeller used for a double suction centrifugal pump, wherein the circumferential positions of the blades are changed to face each other.   In a double suction centrifugal impeller that sucks in from both sides in the axial direction and discharges in the radial direction, a pair of single suction centrifugal impellers formed on a mirror surface and a disk-shaped member disposed between the single suction centrifugal impellers The single suction centrifugal impeller includes a side plate, a plurality of blades extending to substantially the same outer diameter as the side plate, and a main plate having a smaller diameter than the side plate. An impeller used for a double-suction centrifugal pump, characterized in that the circumferential positions of the blades are aligned with each other and are opposed to the back.   5. The impeller according to claim 4, wherein a plurality of through holes are formed in the disk-shaped member, and the plurality of through holes are formed between blades of a pair of single suction centrifugal impellers. .   The disk-shaped member is provided with a rectifying blade narrower than an outlet width of the single suction impeller, and the rectifying blade is positioned between the blades of the single suction impeller. The impeller described.   5. The impeller according to claim 4, wherein a plurality of grooves are formed in the disk-shaped member, and ends of the plurality of blades of the single suction impeller are fitted into the grooves.   In a manufacturing method of an impeller used for both suction centrifugal pumps, after a pair of single suction centrifugal impeller members having a main plate outer diameter smaller than a side plate outer diameter are formed as mirror surfaces, the single suction centrifugal impeller is formed into a disk-shaped member. And a pair of single-suction centrifugal impellers in which the circumferential phases of the blades are changed from each other. The plurality of rectifying blades having a blade height lower than the plurality of blades forming the single suction impeller are formed on the outer diameter side of the main plate outer diameter of the disk-shaped member. The manufacturing method of the impeller described in 2.

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