JP2012082778A - Centrifugal pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal pump by which a favorable operation water volume range can be selected by optionally changing a water volume at the highest efficiency according to a combination of one casing and one impeller.SOLUTION: The centrifugal pump includes: an impeller 12 connected to a rotary shaft 26 and rotated; a casing 10 having a discharge port 10b and housing the impeller 12 inside; a casing cover 14 for sealing an opening of the casing 10; a guide plate 34 having a plurality of passage 40, 42, 44, 46 penetrating the impeller 12 side and the casing 10 side and arranged concentrically with impeller 12 in the casing 10 so that one passage 40 of the plurality of passages communicate with the discharge port 10b; and a closing member 50 for closing passages 42, 44, 46 other than one passage 40 communicated with the discharge port 10b of a guide plate 30 on the impeller 12 side.

Description

  The present invention relates to a centrifugal pump, and more particularly to a low specific speed centrifugal pump having a maximum efficiency point on the small water volume side.

  In general, a centrifugal pump is configured such that an impeller fixed to a rotating shaft that rotates as a motor is driven is rotatably disposed inside a casing, and the impeller is rotated so that fluid that has flowed into the casing is impeller driven. The pressure is increased by the rotation of and the gas flows out of the casing. Here, for example, a throttle part is provided at the outlet part of the casing, and the amount of water is throttled at the throttle part, or an orifice for restricting the water quantity is provided at the outlet of the casing so as to have the highest efficiency point on the low water quantity side. A low specific speed centrifugal pump is constructed.

  FIG. 1 shows a water volume-head curve X1 and an efficiency curve Y1 of a low specific speed centrifugal pump (specific low specific speed centrifugal pump) designed to achieve a maximum efficiency η1 with a water volume a1. In a low specific speed centrifugal pump, it is preferable to operate with a water amount as close as possible to the maximum efficiency η1 of the pump in order to reduce noise and vibration and to stabilize the pump mechanically. For this reason, for example, 80% of the maximum efficiency point water amount a1 is set to the minimum water amount a1 ′ (= a1 × 0.8), and for example, 110% is set to the maximum water amount a1 ″ (= a1 × 1.1). It is widely performed that this water amount range (a1 ′ to a1 ″) is defined as a pump operation water amount range A1.

  For this reason, if the specific low specific speed centrifugal pump is used to respond to the request for operation at the water amount a2 shown in FIG. 1, for example, out of the operating water amount range A1 of the specific low specific speed centrifugal pump, the water amount a2 The efficiency η2 of the specific low specific speed centrifugal pump in FIG. 3 is greatly deviated from the maximum efficiency point and considerably lower than the maximum efficiency η1, and noise and vibration may occur. Therefore, in such a case, the water amount-head curve X2 and the efficiency curve Y2 as shown by the broken line in FIG. 2 are provided, and the maximum efficiency is achieved with the water amount a2, or this water amount a2 is the operating water amount of the pump. A low specific speed centrifugal pump that is in the range A2 is widely used separately from a specific low specific speed centrifugal pump.

  As the impeller used for the low specific speed centrifugal pump having the highest efficiency point on the small water volume side, the applicant applies between the back surface of one blade (main wing) adjacent to each other and the surface of the other blade (main wing). An impeller provided with partitioning blades located inside the outer diameter of the impeller and extending from the back surface of one blade toward the surface of the other blade has been proposed (see Patent Document 1). In addition, a cylindrical auxiliary ring fitted to the outer peripheral portion of the impeller body having the first liquid passage is provided, and the second liquid passage extending from the inner peripheral portion to the outer peripheral portion of the auxiliary ring is provided in the auxiliary ring. The provided impeller is proposed (refer patent document 2).

JP 2007-51592 A Japanese Patent Laid-Open No. 2005-23794

  However, in order to respond to various requests from customers, designing and manufacturing a centrifugal pump that satisfies different performance each time increases design costs, manufacturing costs, material costs, etc., and increases the cost of the centrifugal pump itself. It will be connected. In addition, if the material is consumed in this way, it becomes a waste of limited resources. Even in the impellers described in Patent Documents 1 and 2, it is necessary to process the impeller itself according to the pump performance, and one impeller is required for a centrifugal pump having one performance. For this reason, a plurality of performances cannot be arbitrarily selected with one impeller.

  The present invention has been made in view of the above circumstances, and can be configured while arbitrarily selecting a preferable operating water amount range by arbitrarily changing the maximum amount of water by combining one casing and one impeller. An object of the present invention is to provide a centrifugal pump.

  The invention according to claim 1 is an impeller coupled to a rotating shaft and rotating, a casing having a discharge port and accommodating the impeller therein, a casing cover for sealing an opening of the casing, and a blade A guide plate that has a plurality of passages penetrating the vehicle side and the casing side, and is arranged concentrically with the impeller in the casing so that one passage in the plurality of passages communicates with the discharge port. And a closing member that closes a passage other than the one passage communicating with the discharge port of the guide plate on the impeller side.

  Thus, for example, when the guide plate has two passages of the first passage and the second passage, the first passage of the guide plate and the discharge port of the casing are communicated with each other to constitute the first centrifugal pump. By connecting the second passage and the discharge port of the casing to each other, a second centrifugal pump having a performance different from that of the first centrifugal pump can be configured. The first centrifugal pump closes the impeller side of the second passage and the second centrifugal pump closes the impeller side of the first passage with a closing member. It is possible to prevent the flow from being disturbed near the entrance of the passage and the efficiency from being lowered.

The invention according to claim 2 is characterized in that the guide plate is disposed in the casing so as to be rotatable in the circumferential direction and is fixed to the casing or the casing cover. It is.
Thus, when the guide plate is arranged and fixed to the casing or the casing cover so that one of the plurality of passages provided in the guide plate communicates with the discharge port of the casing, the guide plate is rotated in the circumferential direction to thereby guide the guide plate. The arrangement of the plate with respect to the casing or the casing cover can be easily adjusted.

The invention according to claim 3 is the centrifugal pump according to claim 1 or 2, wherein each of the plurality of passages of the guide plate has a different cross-sectional area in a part of the passage.
Each passage of the guide plate is set so that the centrifugal pump has a predetermined pump performance when the passage is communicated with the discharge port of the casing to constitute a centrifugal pump.

The invention according to claim 4 is characterized in that the closing member is constituted by one arcuate partition plate inscribed in the impeller side of the guide plate. It is a centrifugal pump as described above.
Thereby, when three or more passages are provided in the guide plate, two or more passages can be closed simultaneously by one partition plate.

According to a fifth aspect of the present invention, the partition plate has a shape in which the thickness decreases toward the outlet direction of the flow path so that a flow path serving as a volute is formed between the partition plate and the outer peripheral end surface of the impeller. The centrifugal pump according to claim 4, wherein the centrifugal pump is formed.
Thereby, a fluid can flow more smoothly along the flow path used as the volute formed between the outer peripheral end surface of an impeller and a partition plate.

The invention according to claim 6 is the centrifugal pump according to claim 4 or 5, wherein the partition plate is formed integrally with the casing cover.
Thereby, attachment of a casing cover and a partition plate becomes easy.

  According to the centrifugal pump of the present invention, the centrifugal pump can be configured while arbitrarily selecting a preferable operating water amount range by arbitrarily changing the maximum amount of water by combining one casing and one impeller. . This eliminates the need to design and manufacture centrifugal pumps for each amount of water used by customers, eliminates waste of materials, etc., reduces cost of centrifugal pumps, and eliminates wasteful use of valuable earth resources. It can lead to energy saving.

  In addition, a centrifugal pump with a small amount of water and a high head that employs a general centrifugal pump structure generally has a small exit passage area, and when trying to obtain a casing by casting, the passage may not be reliably molded in the casing. However, since the guide plate used in the centrifugal pump of the present invention, which is provided with a passage that determines pump performance, has an open passage, it can be molded relatively easily by casting.

It is a graph which shows the water quantity-head curve and efficiency curve of one low specific speed centrifugal pump. It is a graph which shows the water volume-lift curve and efficiency curve of another low specific speed centrifugal pump with the water volume-lift curve and efficiency curve shown in FIG. It is a vertical front view of the centrifugal pump of the embodiment of the present invention. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is sectional drawing along the channel | path of the guide plate connected to the discharge port of a casing which shows a part of centrifugal pump shown in FIG. It is the FIG. 3 equivalent view of the centrifugal pump of other embodiment of this invention. FIG. 6 is a view corresponding to FIG. 4 of a centrifugal pump according to still another embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 4 of a centrifugal pump according to still another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the following examples, the same or corresponding members are denoted by the same reference numerals, and redundant description is omitted.
3 is a longitudinal front view of the centrifugal pump according to the embodiment of the present invention, FIG. 4 is a cross-sectional view taken along line AA of FIG. 3, and FIG. 5 is a part of the centrifugal pump shown in FIG. It is sectional drawing along the channel | path of the guide plate connected to a discharge outlet.

  As shown in FIGS. 3 to 5, the centrifugal pump includes a casing 10 having a suction port 10 a and a discharge port 10 b, an impeller 12 that is rotatably accommodated in the casing 10, and an impeller 12 inside. A casing cover 14 for sealing the opening of the accommodated casing 10 is provided. The casing cover 14 is fixed to the casing 10 via bolts 16.

  The impeller 12 is fixed to an end portion on the casing 10 side of a rotating shaft 26 rotatably supported by bearings 22 and 24 incorporated in a bearing body 20 connected to the casing cover 14. The other end of the rotating shaft 26 extends outside from the bearing body 20 and is connected to a motor (not shown). Thereby, the impeller 12 rotates integrally with the rotating shaft 26 as the motor is driven.

  In this example, the impeller 12 is configured by radially arranging a plurality of blades 32 extending linearly on the surface of a disk-shaped main plate (hub) 30. However, various impellers such as a closed type, an open type, and a semi-open type can be applied depending on applications. On the inner surface of the casing 10 on the side of the impeller 12, a guide plate 34 surrounding the periphery of the impeller 12 is disposed concentrically with the impeller 12 so as to be rotatable in the circumferential direction, and is attached to the casing cover 14 via bolts 36. It is fixed. Thus, a circumferentially continuous flow path 38 is formed between the outer peripheral end face of the impeller 12 and the guide plate 34.

  The guide plate 34 extends in the tangential direction of the flow path 38 and penetrates the impeller 12 side and the casing 10 side. In this example, the first passage 40, the second passage 42, the third passage 44, and the fourth passage. Four passages that determine 46 pump performances are provided. These passages 40, 42, 44, 46 open to the casing cover 14 side and are arranged at equal intervals along the circumferential direction of the guide plate 34. The number of passages provided in the guide plate may be two or more, and the arrangement positions of the passages may not be equally spaced along the circumferential direction of the guide plate.

  The guide plate 34 having such a shape is formed with four passages 40, 42, 44, and 46 having a predetermined shape that determines pump performance, but these passages 40, 42, 44, and 46 are formed on the casing cover 14 side. Therefore, it can be molded relatively easily by casting.

  The outlet end of each passage 40, 42, 44, 46 contacting the discharge port 10 b of the pump casing 10 can smoothly flow the fluid that has flowed through each passage 40, 42, 44, 46 into the discharge port 10 b of the casing 10. Thus, it is formed in the same shape as the inlet end of the discharge port 10 b of the casing 10. The passage portions of the passages 40, 42, 44, 46 other than the outlet end contacting the discharge port 10 b of the pump casing 10 have different cross-sectional areas, and each of the passages 40, 42, 44, 46 has a different pump. It is set so that the performance can be determined.

  As shown in FIGS. 3 to 5, the passage portion of the first passage 40 is configured such that when the first passage 40 is communicated with the discharge port 10 b of the casing 10 to form a first centrifugal pump, the amount of water in the first centrifugal pump is -The head curve and the efficiency curve are set so as to coincide with the water amount-head curve X1 and the efficiency curve Y1 shown in FIG.

  The passage portion of the second passage 42 is formed when the second centrifugal pump is configured by rotating the guide plate 34 shown in FIG. 4 by 90 ° clockwise and communicating the second passage 42 with the discharge port 10b of the casing 10. The water amount-lifting curve and the efficiency curve of the second centrifugal pump are set so as to coincide with, for example, the water amount-lifting curve X2 and the efficiency curve Y2 shown in FIG.

  When the guide plate 34 shown in FIG. 4 is rotated 180 ° clockwise and the third passage 44 communicates with the discharge port 10b of the casing 10 to form a third centrifugal pump. The water amount-lifting curve and the efficiency curve of the third centrifugal pump are set to have, for example, a water amount-lifting curve and an efficiency curve other than the water amount-lifting curve and the efficiency curve shown in FIGS.

  Similarly, in the passage portion of the fourth passage 46, the guide plate 34 shown in FIG. 3 is rotated 270 ° clockwise, and the fourth passage 46 is communicated with the discharge port 10b of the casing 10 to constitute a fourth centrifugal pump. In this case, the water amount-lifting curve and the efficiency curve of the fourth centrifugal pump are other than the water amount-lifting curve and the efficiency curve shown in FIGS. 1 and 2, for example, and the water amount-lifting curve and the efficiency curve obtained by the third centrifugal pump. It is set to have a water volume-head curve and an efficiency curve.

  Therefore, a centrifugal pump is configured by connecting any one of the passages 40, 42, 44, and 46 provided in the guide plate 34 and the discharge port 10a of the casing 10 to each other, so that different water amount-head curves and performance are obtained. Four types of centrifugal pumps with curves are obtained. As a result, a new centrifugal pump is designed, and the guide plate 34 that communicates with the discharge port 10b of the casing 10 is simply used by using one casing 10 and one impeller 12 without manufacturing a new centrifugal pump. By arbitrarily selecting the passages 40, 42, 44, 46, it is possible to configure a centrifugal pump having different water volume-lift curves and performance curves.

  In this example, the guide plate 34 is provided with four passages 40, 42, 44, and 46 that determine the pump performance, so that four different water-head curves and performance are obtained depending on the combination of one casing 10 and one impeller 12. A centrifugal pump having a curve can be constructed. That is, it is possible to configure a centrifugal pump having a water amount-head curve and a performance curve that differ by the number of passages that determine the pump performance provided in the guide plate 34.

  Here, as shown in FIGS. 3 to 5, when the first passage 40 provided in the guide plate 34 is communicated with the discharge port 10 b of the casing 10, other than the first passage 40 provided in the guide plate 34. The passages 42, 44, 46 are not used as water passages. Then, in this state, when the impeller 12 of the centrifugal pump is rotated to start pumping, water enters other unused passages 42, 44, 46 other than the first passage 40, and the passages 42, 44, The flow is disturbed near the entrance of 46, and the efficiency is reduced (the flow is disturbed and becomes a loss). In order to prevent this, the other passages 42, 44, 46 other than the first passage 40 of the guide plate 34 are closed at positions where the other passages 42, 44, 46 are closed on the impeller 12 side. A partition plate 50 constituting the member is provided.

  In this example, the partition plate (closing member) 50 is formed of a single arc-shaped plate inscribed in the inner peripheral surface of the guide plate 34 and is provided integrally with the casing cover 14. Thus, for example, when the guide plate 34 shown in FIG. 3 is rotated 90 ° clockwise to connect the second passage 42 provided in the guide plate 34 to the discharge port 10 b of the casing 10, The other passages 40, 44 and 46 are closed by the partition plate 40.

  Further, in this example, as the partition plate 50, the flow path 38 formed between the outer peripheral end face of the impeller 12 and the partition plate 50 forms a volute having a front opening extending in the direction of water flow. The one whose thickness is gradually reduced toward the exit direction is used. That is, the thickness t1 of the end portion on the first passage 40 side of the guide plate 34 of the partition plate 50 is thicker than the thickness t2 of the end portion on the fourth passage 46 side of the guide plate 34 (t1> t2).

  According to this example, a centrifugal pump is configured by connecting any one of the passages 40, 42, 44, 46 provided in the guide plate 34 and the discharge port 10b of the casing 10 to each other. Four types of centrifugal pumps with curves and performance curves can be constructed.

  FIG. 6 shows a centrifugal pump according to another embodiment of the present invention. The example shown in FIGS. 3 to 5 is different from the example shown in FIGS. 3 to 5 in that the guide plate 34 is fixed to the casing cover 14 by the bolt 36 in the example shown in FIGS. The plate 34 is fixed to the casing 10 with bolts 36.

  That is, in the example shown in FIGS. 3 to 5, after the guide plate 34 is fixed to the casing cover 14 with the bolts 36, the casing 10 is fixed to the casing cover 14 with the bolts 16. In contrast, in the example shown in FIG. 6, the casing 10 in which the guide plate 34 is fixed in advance by the bolt 36 is fixed to the casing cover 14 by the bolt 16.

  FIG. 7 shows a centrifugal pump according to still another embodiment of the present invention. 3 to 5 of this example is different from the example shown in FIG. 3 to FIG. 5 in that a flat partition plate 52 having a constant thickness t is used as a closing member over the entire surface. The other passages 42, 44 and 46 that are not closed are closed on the impeller 12 side. In this way, the structure can be simplified by using the flat partition plate 52 having a constant thickness t over the entire surface as the closing member.

  FIG. 8 shows a centrifugal pump according to still another embodiment of the present invention. 3 to 5 of this example is different from the example shown in FIG. 3 to FIG. 5 in that the other passages 42, 44, 46 other than the first passage 40, for example, of the partition plate 50 made of a single plate as a closing member. Instead, the plug members 54a, 54b and 54c are individually closed on the impeller 12 side. That is, plug members (closing members) 54a, 54b, 54c are inserted into the inlet side end portions of the passages 42, 44, 46, respectively, and the passage members 42, 44, 46 are plugged (plug members) 54a, 54b, 54c. In order to close individually.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 10 Casing 10a Suction port 10b Discharge port 12 Impeller 14 Casing cover 20 Bearing body 26 Rotating shaft 30 Main plate 32 Blade 34 Guide plate 38 Channels 40, 42, 44, 46 Passage 50, 52 Partition plate (closing member)
54a, 54b, 54b Plug member (closing member)

Claims (6)

An impeller connected to a rotating shaft and rotating;
A casing having a discharge port and containing the impeller inside;
A casing cover for sealing the opening of the casing;
A guide having a plurality of passages penetrating the impeller side and the casing side, and arranged concentrically with the impeller in the casing so that one passage in the plurality of passages communicates with the discharge port. Plates,
A centrifugal pump comprising: a closing member for closing a passage other than the one passage communicating with the discharge port of the guide plate on the impeller side.   The centrifugal pump according to claim 1, wherein the guide plate is disposed in the casing so as to be rotatable in a circumferential direction and is fixed to the casing or the casing cover.   The centrifugal pump according to claim 1, wherein the plurality of passages of the guide plate have different cross-sectional areas in a part of the passages.   The centrifugal pump according to any one of claims 1 to 3, wherein the closing member is configured by a single arc-shaped partition plate inscribed in the impeller side of the guide plate.   The partition plate is formed in a shape whose thickness decreases toward the outlet direction of the flow path so that a flow path serving as a volute is formed between the outer peripheral end face of the impeller. The centrifugal pump according to claim 4.   The centrifugal pump according to claim 4 or 5, wherein the partition plate is integrally formed with the casing cover.

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