WO2023101030A1

WO2023101030A1 - Pump

Info

Publication number: WO2023101030A1
Application number: PCT/JP2022/044661
Authority: WO
Inventors: 拓士池田
Original assignee: 株式会社荏原製作所
Priority date: 2021-12-03
Filing date: 2022-12-05
Publication date: 2023-06-08
Also published as: JP2023082774A

Abstract

The present invention relates to a volute pump that does not have a rotating shaft coupled to an impeller. A casing (6) of a pump (1) comprises: at least three tongue portions (21A, 21B, 21C) arranged at equal intervals around an impeller (7); and at least three side walls (22A, 22B, 22C) connected respectively to the tongue portions (21A, 21B, 21C). The side walls (22A, 22B, 22C) form at least three flow passages (23A, 23B, 23C) for a fluid. Each of the side walls (22A, 22B, 22C) has a volute side surface (30A, 30B, 30C) which extends from one of the tongue portions (21A, 21B, 21C) to a position beyond another adjacent tongue portion. The pump (1) is not provided with a radial bearing for supporting the impeller (7).

Description

pump

The present invention relates to a pump for transferring liquid, and more particularly to a volute pump that does not have a rotating shaft connected to an impeller.

In the fields of precision equipment and medical equipment, there is a demand for miniaturization of pumps used to transfer liquids. However, the pump has a rotating shaft that connects the drive source and the impeller, and further has a bearing that supports the rotating shaft. Therefore, it is difficult to reduce the size of the pump. Therefore, a pump has been developed that does not have a rotating shaft and has a non-contact radial bearing for supporting the impeller.

Magnetic bearings and hydrodynamic bearings are examples of non-contact radial bearings. The magnetic bearing is configured to support the impeller in a non-contact manner by magnetic force generated by applying an electric current to the coil, and the dynamic pressure bearing is configured to support the impeller in a non-contact manner by dynamic pressure of liquid. be. Since these non-contact radial bearings do not involve physical sliding, they can extend the life of the pump, suppress heat generation, and prevent particles from entering the liquid.

JP-A-2003-97491

However, since at least part of the non-contact radial bearing described above is placed inside the pump casing, there is a limit to downsizing the pump as a whole. In particular, it has been difficult to reduce the thickness (dimension in the axial direction) of the pump due to the presence of the non-contact radial bearing.

Therefore, the present invention provides a pump that does not require a mechanical radial bearing for receiving the radial load of the impeller.

In one aspect, a pump for transferring a liquid comprises a casing having a volute chamber therein and an impeller disposed within said volute chamber, said casing being evenly spaced around said impeller. and at least three side walls respectively connected to said at least three tongues, said at least three side walls forming at least three flow paths for said liquid. , each of said at least three side walls having a volute side surface extending from one of said at least three tongues to a position beyond an adjacent other tongue, said pump supporting said impeller; A pump is provided that does not have radial bearings for

In one aspect, a pump for transferring a liquid comprises a casing having a volute chamber therein and an impeller disposed within said volute chamber, said casing being evenly spaced around said impeller. and at least three side walls respectively connected to said at least three tongues, said at least three side walls forming at least three flow paths for said liquid. , each of said at least three sidewalls having a volute side extending from one of said at least three tongues to a position beyond an adjacent other tongue, upstream of said at least three tongues; A pump is provided wherein the radial load of said impeller is supported by at least three pressure maxima occurring at .

In one aspect, a pump for transferring a liquid comprises a casing having a volute chamber therein and an impeller disposed within said volute chamber, said casing being evenly spaced around said impeller. and at least three side walls respectively connected to said at least three tongues, said at least three side walls forming at least three flow paths for said liquid. , each of said at least three sidewalls having a volute side extending from one of said at least three tongues to a position beyond an adjacent other tongue, upstream of said at least three tongues; A pump is provided wherein substantially all of the radial load of said impeller is supported by at least three pressure maxima occurring at .

In one aspect, said at least three tongues have the same shape.
In one aspect, the at least three tongues are arranged rotationally symmetrical about the center of the volute chamber.
In one aspect, the volute sides of the at least three sidewalls have the same shape.
In one aspect, the volute sides of the at least three sidewalls are arranged rotationally symmetrical about the center of the volute chamber.
In one aspect, the inlets of the at least three channels are arranged rotationally symmetrically about the center of the volute chamber.
In one aspect, the at least three channels have different lengths and different widths, the longer the length of each channel, the greater the width of each channel.
In one aspect, the pump further comprises a pivot bearing located between the back surface of the impeller and the inner surface of the casing.
In one aspect, the pump further comprises a non-contact thrust bearing located on the suction side of the impeller.

In one aspect, there is provided a pump apparatus comprising the pump described above and a motor stator configured to generate a rotating magnetic field.

According to the present invention, the pressure of the liquid is locally increased on the upstream side of the at least three tongues arranged around the impeller. That is, at least three pressure maximum points are generated at equal intervals around the impeller. These pressure maxima can support the radial loads of the impeller. Therefore, the radial bearing itself for receiving the radial load of the impeller is no longer required, and the miniaturization of the pump, which could not be achieved conventionally, is realized.

1 is a cross-sectional view of an embodiment of a pumping device; FIG. 2 is a horizontal sectional view of the pump shown in FIG. 1; FIG. Figure 3 shows the casing shown in Figure 2; It is a figure explaining the 1st volute side. FIG. 10 is a cross-sectional view showing another embodiment of a pump device;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing one embodiment of a pump device. The pump device comprises a pump 1 for transferring liquid and a motor stator 2 for driving the pump 1 . The pump 1 comprises a casing 6 having a volute chamber 5 therein, and an impeller 7 arranged within the volute chamber 5 .

The impeller 7 is provided with a plurality of permanent magnets 10. These permanent magnets 10 are embedded in the impeller 7 and are not exposed on the surface of the impeller 7 . The motor stator 2 comprises a plurality of coils 12 and power lines 15 for supplying current to these coils 12 . When current (more specifically, three-phase AC current) is supplied to the coil 12, the motor stator 2 generates a rotating magnetic field. This rotating magnetic field acts on the permanent magnet 10 of the impeller 7 to rotate the impeller 7 . A gap is formed between the pump 1 and the motor stator 2 so that the pump 1 can be separated from the motor stator 2 . Pump 1 may be fixed to motor stator 2 via a bracket (not shown).

The casing 6 has a liquid suction port 18 . As the impeller 7 rotates, the liquid flows into the pump 1 through the suction port 18 , is pressurized by the rotation of the impeller 7 , and is discharged from the pump 1 . Examples of liquids to be transferred by the pump 1 of the present embodiment include pure water, blood, and chemical solutions, but are not limited to these. In particular, as described below, the impeller 7 is completely non-contact supported, so particles and frictional heat due to sliding are not generated. Therefore, the pump 1 is suitable for transporting pure water of extremely high purity and blood that requires a constant temperature.

FIG. 2 is a horizontal sectional view of the pump 1 shown in FIG. As shown in FIG. 2, the impeller 7 is arranged inside the volute chamber 5 . Such a pump 1 is also called a volute pump. The impeller 7 has a plurality of blades 8 . The entire impeller 7 is circular. The casing 6 has three

tongues

21A, 21B, 21C arranged at regular intervals around the impeller 7 and three

side walls

22A, 22B, 22C connected to the

tongues

21A, 21B, 21C, respectively. are doing. The three

side walls

22A, 22B, 22C form three

channels

23A, 23B, 23C for the liquid to be transported. Although in this embodiment there are three

tongues

21A, 21B, 21C, three

corresponding side walls

22A, 22B, 22C, and three

corresponding channels

23A, 23B, 23C, the configuration of the pump 1 is Not limited to this embodiment, four or more tongues, sidewalls and channels may be provided.

When the impeller 7 rotates, the liquid flows from the suction port 18 (see FIG. 1), flows through the impeller 7, and is pressurized as the impeller 7 rotates. The pressurized liquid flows through the three

channels

23A, 23B, 23C. The

channels

23A, 23B, 23C communicate with the volute chamber 5, and

inlets

26A, 26B, 26C of the

channels

23A, 23B, 23C face the volute chamber 5. The liquid separately flows through the three

flow paths

23A, 23B, 23C and is discharged outside through the three

outlets

27A, 27B, 27C of the three

flow paths

23A, 23B, 23C. The

liquid outlets

27A, 27B, 27C are separately provided corresponding to the three

flow paths

23A, 23B, 23C.

FIG. 3 is a diagram showing the casing 6 shown in FIG. The three

sidewalls

22A, 22B, 22C have

volute sides

30A, 30B, 30C, respectively, each of the volute sides 30A, 30B, 30C extending from one of the three

tongues

21A, 21B, 21C. , extending beyond the other adjacent tongue. That is, the first sidewall 22A has a first volute side surface 30A extending from the first tongue 21A to which the first sidewall 22A is connected to a position beyond the adjacent second tongue 21B. The second side wall 22B has a second volute side 30B extending from the second tongue 21B to which the second side wall 22B is connected to a position beyond the adjacent third tongue 21C. The third side wall 22C has a third volute side 30C extending from the third tongue 21C to which the third side wall 22C is connected to a position beyond the adjacent first tongue 21A.

FIG. 4 is an enlarged view showing the first volute side surface 30A. As shown in FIG. 4, the start point S of the first volute side surface 30A is located at the connection point between the first tongue portion 21A and the side wall 22A, and the end point E of the first volute side surface 30A is located at the circumference of the impeller 7. directionally beyond the adjacent second tongue 21B. A first inlet 26A is formed between the first volute side 30A and the second tongue 21B. Although not shown, the second volute side surface 30B and the third volute side surface 30C have the same configuration as the first volute side surface 30A.

As shown in FIG. 3, the volute side surfaces 30A, 30B, 30C are formed from the inner surfaces of the upstream side portions of the

side walls

22A, 22B, 22C and face the volute chamber 5. The volute sides 30A, 30B, 30C form at least part of the volute chamber 5. As shown in FIG. The impeller 7 is surrounded by these volute side surfaces 30A, 30B, 30C.

The three

tongues

21A, 21B, 21C have the same shape. The volute sides 30A, 30B, 30C of the three

sidewalls

22A, 22B, 22C have the same length. Furthermore, the volute sides 30A, 30B, 30C have the same shape. As used herein, the term "same" not only means exactly the same, but also serves the intended purpose of creating a uniform pressure maximum around the impeller 7 to support the radial load of the impeller 7. It also means substantially the same, so far as achievable.

The

tongues

21A, 21B, and 21C are arranged rotationally symmetrically with respect to the center O of the volute chamber 5. That is, when the tongue 21A is rotated about the center O of the volute chamber 5 by an angle, the tongue 21A overlaps the tongue 21B, and the tongue 21A is rotated about the center O of the volute chamber 5 by an angle. Then, the tongue portion 21A overlaps the tongue portion 21C.

The volute side surfaces 30A, 30B, and 30C are also arranged rotationally symmetrically with respect to the center O of the volute chamber 5.

Inlets

26A, 26B, 26C of the

flow paths

23A, 23B, 23C are arranged at regular intervals around the center O of the volute chamber 5 and have the same shape. Further, these three

inlets

26A, 26B, 26C are arranged rotationally symmetrically with respect to the center O of the volute chamber 5. As shown in FIG.

According to the fluid analysis conducted by the present inventor, on the upstream side of the three

tongues

21A, 21B, and 21C of the pump 1 having the rotationally symmetrical structure, there is a maximum pressure point, which is a region where the pressure of the liquid locally increases. It was found that R exists. In particular, it has been clarified from the results of the fluid analysis that three uniform maximum pressure points R are generated around the impeller 7 at regular intervals. Since these pressure maximum points R are evenly spaced around the impeller 7 , they can substantially support all of the radial load of the impeller 7 . Since the radial load of the impeller 7 is supported by the three uniform pressure maximum points R generated upstream of the three

tongues

21A, 21B, 21C, a mechanical radial bearing for supporting the impeller 7 is provided. This eliminates the need for the pump 1 and realizes the miniaturization of the pump 1, which could not be achieved in the past. In particular, according to this embodiment, the pump 1 does not have a mechanical radial bearing for supporting the impeller 7, so the pump 1 can be made very thin.

As shown in FIG. 2, the lengths of the three

flow paths

23A, 23B, and 23C are different. In order to equalize the resistance of the channels to liquid among the three

channels

23A, 23B, 23C, in one embodiment the width of the channels may increase along with the length of the channels. That is, the longest first flow path 23A has the greatest width, the second longest second flow path 23B has a smaller width than the first flow path 23A, and the shortest third flow path 23B has a smaller width than the first flow path 23A. Channel 23C has a smaller width than second channel 23B. Such a flow channel shape is expected to contribute to the uniformity of the maximum pressure points R generated upstream of the three

tongues

21A, 21B, and 21C.

The pump 1 further comprises a pivot bearing 45 arranged between the back surface of the impeller 7 and the inner surface of the casing 6, as shown in FIG. The pivot bearing 45 is composed of a spherical body that is a separate structure from the impeller 7 and the casing 6 . A first recessed portion 41 is provided on the rear surface of the impeller 7 , and a second recessed portion 42 facing the first recessed portion 41 is provided on the inner surface of the casing 6 . A spherical pivot bearing 45 is arranged between the first recess 41 and the second recess 42 , and positioning of the pivot bearing 45 is achieved by the first recess 41 and the second recess 42 .

The pivot bearing 45 functions when the impeller 7 is started. More specifically, when the motor stator 2 generates a rotating magnetic field, the impeller 7 is drawn toward the motor stator 2 . The pivot bearing 45 supports the load of the impeller 7 toward the motor stator 2 and prevents the entire back surface of the impeller 7 from coming into contact with the inner surface of the casing 6 (surface contact). Since the impeller 7 can rotate around the pivot bearing 45, the impeller 7 can smoothly start its rotation.

Due to the presence of the pivot bearing 45, a gap is always formed between the back surface of the impeller 7 and the inner surface of the casing 6. Liquid flows in from the suction port 18 and is pressurized as the impeller 7 rotates. The pressurized liquid fills the gap between the back surface of the impeller 7 and the inner surface of the casing 6 and generates a thrust load that pushes the impeller 7 toward the suction side. This thrust load moves the impeller 7 to the suction side, and as a result, the impeller 7 is separated from the pivot bearing 45 . That is, the impeller 7 is out of contact with the pivot bearing 45 during operation of the pump 1 .

In one embodiment, the pivot bearing 45 may be a protrusion protruding from the back surface of the impeller 7. For example, pivot bearing 45 may be a curved or conical protrusion protruding from the back surface of impeller 7 .

As shown in FIG. 1, the pump 1 includes a non-contact thrust bearing 50 arranged on the suction side of the impeller 7 to receive the thrust load described above. In the embodiment shown in FIG. 1, the non-contact thrust bearing 50 is a hydrodynamic bearing. More specifically, a spiral groove 51 is formed on the surface of the impeller 7 on the suction side, and the spiral groove 51 generates dynamic pressure of the liquid when the impeller 7 rotates. The thrust load of the impeller 7 is received by the dynamic pressure of this liquid.

In one embodiment, the non-contact thrust bearing 50 may be a magnetic bearing. For example, magnetic bearings using permanent magnets may be provided. However, from the viewpoint of miniaturizing the pump 1, a hydrodynamic bearing as shown in FIG. 1 is more suitable.

FIG. 5 is a cross-sectional view showing another embodiment of the pump device. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to FIGS. 1 to 4, so redundant description thereof is omitted. The impeller 7 of the pump 1 of this embodiment has a return channel 60 formed at its center. This return channel 60 penetrates the impeller 7 in its axial direction.

As the impeller 7 rotates, the liquid flows in from the suction port 18 and is pressurized as the impeller 7 rotates. Part of the pressurized liquid fills the gap between the back surface of the impeller 7 and the inner surface of the casing 6 and flows through the return flow path 60 to the suction side of the impeller 7 . Such a liquid flow can prevent stagnation (stagnation) of the liquid in the gap between the back surface of the impeller 7 and the inner surface of the casing 6 . The pump 1 according to the embodiment shown in FIG. 5 is suitable for transporting blood.

The above-described embodiments are described for the purpose of enabling those who have ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiments can be made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in its broadest scope in accordance with the technical spirit defined by the claims.

The present invention can be used for volute pumps that do not have a rotating shaft connected to an impeller.

1 Pump 2 Motor Stator 5 Volute Chamber 6 Casing 7 Impeller 8 Blade 10 Permanent Magnet 12 Coil 15 Power Line 18

Suction Ports

21A, 21B, 21C

Tongues

22A, 22B,

22C Side Walls

23A, 23B,

23C Channels

26A, 26B,

26C Inlets

27A, 27B,

27C Outlets

30A, 30B, 30C Volute side surface 41 First recess 42 Second recess 45 Pivot bearing 50 Non-contact thrust bearing 51 Spiral groove 60 Return flow path

Claims

A pump for transferring a liquid, comprising:
a casing having a volute chamber therein;
An impeller arranged in the volute chamber,
The casing is
at least three tongues evenly spaced around the impeller;
having at least three sidewalls respectively connected to the at least three tongues;
the at least three sidewalls form at least three flow paths for the liquid;
each of the at least three sidewalls having a volute side extending from one of the at least three tongues to a position beyond an adjacent other tongue;
A pump, wherein the pump does not have a radial bearing for supporting the impeller.
A pump for transferring a liquid, comprising:
a casing having a volute chamber therein;
An impeller arranged in the volute chamber,
The casing is
at least three tongues evenly spaced around the impeller;
having at least three sidewalls respectively connected to the at least three tongues;
the at least three sidewalls form at least three flow paths for the liquid;
each of the at least three sidewalls having a volute side extending from one of the at least three tongues to a position beyond an adjacent other tongue;
A pump, wherein the radial load of the impeller is supported by at least three pressure maxima occurring upstream of the at least three tongues.
A pump for transferring a liquid, comprising:
a casing having a volute chamber therein;
An impeller arranged in the volute chamber,
The casing is
at least three tongues evenly spaced around the impeller;
having at least three sidewalls respectively connected to the at least three tongues;
the at least three sidewalls form at least three flow paths for the liquid;
each of the at least three sidewalls having a volute side extending from one of the at least three tongues to a position beyond an adjacent other tongue;
A pump configured such that substantially all of the radial load of the impeller is supported by at least three pressure maxima occurring upstream of the at least three tongues.
The pump according to any one of claims 1 to 3, wherein said at least three tongues have the same shape.
The pump according to claim 4, wherein said at least three tongues are arranged rotationally symmetrically with respect to the center of said volute chamber.
A pump according to any one of claims 1 to 5, wherein the volute sides of the at least three side walls have the same shape.
The pump according to claim 6, wherein the volute sides of the at least three side walls are arranged rotationally symmetrically about the center of the volute chamber.
The pump according to any one of claims 1 to 7, wherein the inlets of said at least three flow paths are arranged rotationally symmetrically with respect to the center of said volute chamber.
the at least three channels have different lengths and different widths;
9. A pump according to any preceding claim, wherein the longer the length of each channel, the greater the width of each channel.
A pump according to any one of claims 1 to 9, further comprising a pivot bearing arranged between the back surface of the impeller and the inner surface of the casing.
The pump according to any one of claims 1 to 10, further comprising a non-contact thrust bearing arranged on the suction side of said impeller.
A pump according to any one of claims 1 to 11;
A pumping device comprising a motor stator configured to generate a rotating magnetic field.