JPH09209965A - Full circumferential flow type pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a pump compact by providing a mixed flow pump of which impeller front surface is directed to a motor at one end of a motor shaft. SOLUTION: A canned motor 6 is contained in a pump casing 1, and a mixed flow type impeller 8 is fixed to an end part of a main shaft 7 of it to compose a full circumferential flow type mixed flow pump. Thus mixed flow type impeller 8 is disposed vvith an impeller front surface (suction mouth) directed toward the canned motor 6. The pump casing 1 has a cylindrical outer cylinder 2 and a discharge casing 3 connected to one end of the outer cylinder 2 by flanges 61, 62. An outer end part of the outer cylinder 2 is throttled, where a suction nozzle 4 is fixed. A discharge nozzle 5 is fixed to a tip of the discharge casing 3. The impeller 8 is set in a relation of the maximum diameter D2max <= a pump discharge aerture Φd. In this constitution, flow in a circular flow passage can be set as a simple axial direction speed component, thereby noise can be restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-circulation pump
In particular, the present invention relates to an all-round type mixed flow pump equipped with a mixed flow pump having a relatively high specific speed.

[0002]

2. Description of the Related Art As a full-circulation type mixed flow pump, for example, the one described in JP-A-53-139203 is known. The mixed flow pump described in Japanese Patent Laid-Open No. 53-139203 is provided with an impeller for a mixed flow pump, the front surface of which is directed to the pump suction port at one end of the motor shaft. The handling liquid discharged from the impeller is guided to an annular space provided on the outer peripheral portion of the motor stator, and is discharged from the pump discharge port on the opposite side via the motor between the pump suction port and the motor.

Guide vanes are provided in the annular space, and the dynamic pressure due to the circumferential velocity component of the handled liquid is recovered as static pressure. That is, the pressure recovery is measured by making the handling liquid that spirally flows at an extremely high speed flow at a low speed in the axial direction.

Further, JP-A-53-139203 also describes the purpose of miniaturizing the pump by rotating the impeller at a relatively high speed.

[0005]

However, the mixed flow pump described in JP-A-53-139203 has the following problems. That is, since the guide vanes are provided in the annular flow path, noise is generated by the circumferential velocity component.
Noise is also generated by the flow separation phenomenon caused by the guide vanes. The above-mentioned separation phenomenon becomes remarkable especially in the partial flow rate range and the excessive flow rate range deviating from the design point.

On the other hand, the mixed flow pump originally has a characteristic that the shaft power characteristic is flat in a wide range of flow rate and that it can be operated practically without any trouble even at an operating point deviating from the design point. Therefore, although the pump described in the above publication is a mixed flow pump, due to the problem of noise,
There is a possibility that the operating range used will be limited.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a small-sized, high-efficiency full-circumference type mixed flow pump having a low noise value.

[0008]

In order to achieve the above-mentioned object, the present invention uses the following means. A diagonal flow pump with the front of the impeller facing the motor was provided at one end of the motor shaft of the all-circulation pump. As a result, the flow in the annular flow path has only a simple axial velocity component, and noise is suppressed. A discharge casing was provided on the back side of the impeller, and a guide device was provided in the discharge casing. There is a space between the outer periphery of the guide device and the inner surface of the discharge casing, and the space is filled with the handling liquid. As a result, the vibration and noise generated in the guide device are attenuated by the liquid handled in the space. That is, the noise value can be reduced. A constraint condition was set between the outer diameter of the impeller and the pump discharge port diameter. As a result, since the guide device can be accommodated in the discharge casing without waste, the outer dimensions of the pump such as the face-to-face dimension can be reduced. A constraint condition is set between the outer diameter of the impeller and the outer diameter of the motor stator. As a result, it is possible to put together the all-round type mixed flow pump without waste as a whole. A guide device was fitted to the inner circumference of the discharge casing. As a result, the guide device can be fixed very easily without using a special mounting member such as a bolt. Further, as described above, by providing a constraint condition between the outer diameter dimension of the impeller and the pump discharge port diameter, the flow path shape of the guide device also becomes suitable.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an all-circumferential flow type pump according to the present invention will be described below with reference to FIG. FIG. 1 is a sectional view showing an all-round type mixed flow pump according to the present invention, and FIG.
FIG. 2 is a sectional view taken along line II.

The all-round mixed flow pump shown in this embodiment is fixed to a pump casing 1, a canned motor 6 housed in the pump casing 1, and an end of a main shaft 7 of the canned motor 6. The mixed flow type impeller 8 is provided. The mixed flow impeller 8 has the impeller front surface (suction mouse) facing the canned motor 6 side. The pump casing 1 is composed of a substantially cylindrical pump casing outer cylinder 2 and a discharge casing 3 connected to one end of the pump casing outer cylinder 2 by flanges 61 and 62. The flanges 61 and 62 constitute a fixing means for fixing another member such as the discharge casing 3 to the outer cylinder 2. The pump casing outer cylinder 2 and the discharge casing 3 are formed of sheet metal made of stainless steel or the like.

The other end of the outer cylinder 2 is squeezed and the suction nozzle 4 is fixed. A discharge nozzle 5 is fixed to the tip of the discharge casing 3. A bracket 45 is attached to the outer surface of the outer cylinder 2. The frequency converter assembly 50 is attached to the bracket 45.
The frequency converter assembly 50 includes a base 46 attached to the bracket 45 and a cover 4 attached to the base 46.
7 and a frequency converter main body 48 surrounded by a base 46 and a cover 47.

The impeller 8 is a precision cast product of stainless steel casting. This is because unlike a press-made impeller, it is easy to realize a three-dimensional blade shape, and it is advantageous in terms of pump efficiency and suction performance. Also, because it is precision casting,
This is because the casting surface of the flow path of the impeller has a fine texture and is therefore efficient.

The bracket 45 has a hole for electrically connecting the canned motor 6 and the frequency converter main body 48. The bracket 45, the base 46, and the cover 47 are each made of a good heat conductor made of an aluminum alloy.

On the other hand, the canned motor 6 includes a stator 13
A motor frame outer case 14 provided on the outer peripheral part of the stator 13, motor frame side plates 15 and 16 welded and fixed to both open ends of the motor frame outer case 14, and an inner peripheral part of the stator 13. The motor frame side plate 15 is fitted and attached,
A can 17 that is welded and fixed to 16 is provided. A rotor 18 rotatably housed in the stator 13 is shrink-fitted and fixed to the main shaft 7. An annular space (flow path) 40 is formed between the motor frame outer case 14 and the outer cylinder 2.

Further, the motor frame side plate 16 of the canned motor 6 holds a suction bracket 11 for guiding the fluid from the outer side to the inner side in the radial direction. Suction bracket 11
A liner ring 51 is provided on the inner side of, and the liner ring 51 slides on the front surface of the impeller 8 (on the suction mouth side). A guide device 12 is arranged in the discharge casing 3. The guide device 12 guides the fluid discharged from the mixed flow impeller 8 to the pump discharge port. A rib 12 a provided on the outer circumference of the guide device 12 is fitted into the inner diameter of the discharge nozzle 5. A gasket 52 is interposed between the guide device 12 and the discharge nozzle 5, and a gasket 53 is also provided between the guide device 12 and the suction bracket 11.
Is interposed. The tip of the discharge nozzle 5 is a sealing surface 5a for preventing leakage of the handling liquid between the discharge nozzle 5 and a counterpart member connected to the pump.

A lead wire housing 20 is fixed to the outer frame 14 of the motor frame by welding. The lead wire is pulled out from the coil inside the outer body 14 of the motor frame through the lead wire housing 20, and a hole of the bracket 45 is provided. , The frequency converter main body 48 in the base 46 and the cover 47 is connected through the lead wire extraction hole of the base 46.

Next, the peripheral portion of the bearing on the side of the impeller 8 will be described. The bearing bracket 21 includes a radial bearing 22 and
A fixed thrust bearing 23 is provided. The end surface of the radial bearing 22 also has a function as a fixed-side thrust sliding member. A rotary side thrust bearing 24 and a rotary side thrust bearing 25, which are rotary side thrust sliding members, are provided on both sides of the radial bearing 22 and the fixed side thrust bearing 23.
Is provided. The rotation side thrust bearing 24 is fixed to the thrust disk 26, and the thrust disk 26
Is fixed to the main shaft 7 via a key. The rotation side thrust bearing 25 is fixed to a thrust disk 27, and this thrust disk 27 is fixed to the main shaft 7 via a key.

The bearing bracket 21 is inserted into a spigot provided on the motor frame side plate 16 via an O-ring 29 made of an elastic material. Bearing bracket 2
1 is in contact with the motor frame side plate 16 via a gasket 30 made of an elastic material. Reference numeral 31 in the drawing denotes a sleeve which forms a sliding portion with the radial bearing 22.

Next, the peripheral portion of the bearing on the side opposite to the impeller 8 will be described. The bearing bracket 32 is provided with a radial bearing 33. Reference numeral 34 in the figure denotes a sleeve that forms a sliding portion with the radial bearing 33, the sleeve 34 contacts a washer 35, and this washer 35 is fixed by a screw and a double nut 36 provided on the shaft portion of the main shaft 7. . The bearing bracket 32 is inserted into a spigot provided on the motor frame side plate 15 via an O-ring 37 made of an elastic material. The bearing bracket 32 is in contact with the motor frame side plate 15.

A stay 43 is connected to the outer casing 14 of the motor frame, and the stay 43 and the outer cylinder 2 are fixed by welding. The rotation speed of the canned motor 6 is set to 4000 rpm or more by the frequency converter main body 48.

The operation of the full-circulation pump shown in FIG. 1 will be briefly described. The fluid sucked from the suction nozzle 4 is formed between the outer cylinder 2 and the motor frame outer shell 14 of the canned motor 6. It flows into the annular flow passage 40, is guided by the suction bracket 11 through the flow passage 40, and is guided into the impeller 8. The fluid discharged from the impeller 8 is guided by the guide device 12
And is discharged from the discharge nozzle 5 connected to the discharge casing 3.

According to the present invention, a mixed flow pump in which the front surface of the impeller 8 faces the motor is provided at one end of the main shaft 7 of the canned motor 6. Mixed flow pumps are rather low head
It is a pump that corresponds to the design point of large flow rate. This means that an extremely large amount of liquid to be handled flows inside the all-circumferential flow pump of a certain size and motor output. Therefore, if the flow path configuration in the pump is not appropriate, the noise value will increase. The flow path configuration of the pump disclosed in Japanese Patent Laid-Open No. 53-139203 is likely to generate noise as described above. The present invention solves this. Further, in the present invention, the canned motor is used, but the maximum working pressure (suction pressure + pump generation head) of this type of pump is usually determined by the pressure resistance of the can. In the present invention, since the can 17 is configured so that only the suction pressure is applied, it can be used even under a high suction pressure (pushing pressure).

The pump of the present invention is used in combination with an inverter or the like at a rotational speed exceeding 4000 min ^-1 . It is known that, for the same pump performance, the higher the rotational speed, the smaller the impeller size can be. However, if the rotation speed is too high, the so-called suction performance deteriorates, causing a problem of cavitation.

Therefore, in the present invention, the maximum outer diameter D of the impeller is set.
_The rotation speed is determined so that _2max is slightly smaller than the pump discharge port diameter Φ _d . Specifically, 0.8Φ _d ≤
The value D _{2max ≤Φ d} is used. As a result, the guide device 12 can be housed in the discharge casing 3 without waste, and the suction performance can be ensured at a value that does not hinder the operation.

In the present invention, the discharge casing 3 is provided on the back side of the impeller 8. As a result, the handled liquid exists between the guide device 12 and the discharge casing 3, so that noise can be effectively reduced.

In the present invention, a mixed flow pump is provided at one end of the main shaft 7 of the canned motor 6. The definition of the mixed flow pump is not clear, but in the present invention, when the flow rate is Q (m ³ / min), the lift is H (m), and the rotation speed is n (min ⁻¹ ), the specific speed is The value of N _s = nQ ^1/2 / H ^3/4 is 400 ≦ N _S ≦ 1300
And

In the present invention, the most effective rotation speed n is 400.
It is set to 0 min ^-1 or more. By increasing the number of rotations, the outer diameter of the impeller is reduced, and the guide device and other components are better accommodated.

[0028] The present invention is directed to D _2max ≦ 0.7D _s the relationship of the impeller outer diameter D _2max and the motor stator outer diameter D _s.
Under this condition, by operating at a rotation speed of 4000 min ^-1 or more, it is possible to eliminate waste and overload from the structure of the entire pump.

[0029] Further, the present invention is, as a relation of the outer diameter D _S of diameter [Phi _d and the motor stator of the pump discharge port Φ _d ≧ 0.6D _S,
The most suitable dimensional constraints are presented. By satisfying these conditions, a very small pump device can be provided.

Further, according to the present invention, a mixed flow pump is provided at one end of the main shaft of the canned motor 6, and the main flow of the pump suction liquid is provided in the annular space 40 formed between the outer peripheral surface of the motor frame outer cylinder 14 and the outer cylinder 2. Is configured to be guided. As a result, the flow in the annular space (flow path) 40 has only a simple axial component, and noise is suppressed.

Further, according to the present invention, the frequency converter is attached to the outer surface of the outer cylinder 2. Although the frequency converter is accompanied by heat generation, the frequency converter can be downsized because it can be cooled by the liquid handled by the pump by configuring as in the present invention. Since the pump part becomes smaller by increasing the rotation speed,
It goes without saying that the structural unit will also be small.

Further, according to the present invention, the pump suction port S _P and the pump discharge port O _P are arranged on the axis of the motor shaft. This flow path configuration is the most straightforward, has low noise, and has no secondary flow component, and is therefore efficient.

In the present invention, the outer diameter D _BS of the bearing bracket 32 on the pump suction port side is smaller than the suction port diameter Φ _S. Therefore, even if the suction casing is not separately provided at the end of the outer cylinder 2, there is no problem in assembly. In the embodiment shown in FIG. 1, the outer cylinder 2 is extended and a suction nozzle portion is provided at the end of the outer cylinder. As a result, the number of parts can be reduced,
Productivity can be improved.

[0034]

As described above, according to the present invention, due to the flow of the fluid in the annular flow path, the interposition of the fluid around the guide device, etc., the noise value is small, and the size and efficiency are small. A flow pump can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an all-circumferential flow pump according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[Explanation of symbols]

 1 Pump Casing 2 Outer Cylinder 3 Suction Casing 4 Discharge Casing 6 Canned Motor 7 Spindle 8 Impeller 11 Suction Bracket 12 Guide Device 13 Stator 14 Motor Frame Outer Body 15, 16 Motor Frame Side Plate 17 Can 18 Rotor 21, 32 Bearing Bracket 22, 33 Radial bearing 23 Fixed side thrust bearing 24 Rotation side thrust bearing 48 Frequency converter body 50 Frequency converter assembly 51 Liner ring 61, 62 Flange

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kaoru Yagi 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside EBARA Research Institute, Inc. (72) Inventor Keita Uei 4-chome, Fujisawa, Kanagawa No. 1 Incorporated EBARA Research Institute (72) Inventor Yoshiaki Miyazaki 4-2-1 Honfujisawa, Fujisawa-shi, Kanagawa Incorporated EBARA Research Institute (72) Incorporated Katsushi Iijima Motofujisawa, Fujisawa, Kanagawa 4-2-1, Ebara Research Institute, Inc. (72) Inventor Junya Kawabata, 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Ebara Corporation

Claims (15)

[Claims] 1. An all-circumferential flow type pump configured to guide a main flow of a handling liquid to an outer peripheral portion of a motor stator, wherein a mixed flow pump having an impeller front surface facing a motor side is provided at one end of a motor shaft. A characteristic all-round pump. 2. The all-circumferential flow pump according to claim 1, wherein the relationship between the maximum outer diameter D _{2max of the} impeller and the diameter Φ _d of the pump discharge port is D _2max ≦ Φ _d . 3. The full-circumferential flow pump according to claim 1, wherein a discharge casing is provided on the back side of the impeller, and a guide device is provided in the discharge casing. 4. The flow rate is Q (m ³ / min) and the lift is H
(M) and the number of rotations is n (min ^-1 ), the specific speed N _S =
4. The full-circumferential flow pump according to claim 1, wherein the value of nQ ^1/2 / H ^3/4 is 400 ≦ N _S ≦ 1300. 5. The full-circumferential flow pump according to claim 1, wherein the rotation speed n is 4000 (min ⁻¹ ) or more. 6. The relationship between the maximum outer diameter D _{2max of the} impeller and the outer diameter D _S of the motor stator is D _2max ≦ 0.7D _S , according to any one of claims 1 to 5. All-circumferential flow pump described. 7. The relationship between the diameter Φ _d of the pump outlet and the outer diameter D _S of the motor stator is Φ _d ≧ 0.6D _S. Full-circulation pump described in 8. A motor frame outer case provided on an outer peripheral portion of a motor stator, an outer cylinder forming an annular space between the outer peripheral surface of the motor frame outer case, and a pump section for introducing a handling liquid into the annular space. An all-circumferential-type pump including the above, wherein a mixed-flow pump is provided at one end of a motor shaft, and a main flow of the pump suction liquid is introduced into the annular space. 9. The full-circumferential flow pump according to claim 8, wherein a frequency converter is fixed to the outer peripheral portion of the outer cylinder. 10. The pump suction port and the pump discharge port are arranged on the axis of the motor shaft.
All-circumferential flow pump described. 11. An all-circumferential flow type pump configured to guide a main flow of a handling liquid to an outer peripheral portion of a motor stator, wherein an impeller having a front surface facing the motor side is provided at one end of a motor shaft, and an outermost part of the impeller is provided. The relationship between the diameter D _2max and the diameter Φ _d of the pump outlet is D
_An all-circumferential flow type pump characterized in that _2max ≤ Φ _d . 12. In an all-circumferential flow type pump configured to guide a main flow of a handling liquid to an outer peripheral portion of a motor stator, an impeller having a front surface facing the motor side is provided at one end of a motor shaft, and a rear surface of the impeller is provided. A full-circumferential flow pump, characterized in that a discharge casing is provided on the side, and a guide device is fitted inside the discharge casing. 13. The discharge casing comprises a nozzle provided with a sealing surface for preventing leakage of a handling liquid between the discharge casing and a counterpart member connected to the pump, and the guide device is fitted inside the nozzle. The all-circumferential flow type pump according to claim 12, characterized in that they are combined. 14. A motor frame outer case provided on an outer peripheral portion of a motor stator, an outer cylinder forming an annular space between the outer peripheral surface of the motor frame outer case, and a pump section for introducing a handling liquid into the annular space. An all-circumferential-type pump provided with an impeller at one end of a motor shaft and an outer cylinder extending at the other end of the motor shaft to provide a pump suction port. . 15. The full-circumferential flow pump according to claim 14, wherein the relationship between the outer diameter D _BS of the bearing bracket on the pump suction port side and the diameter Φ _s of the pump suction port is D _BS <Φ _s. .