JPH06147183A - Canned motor pump - Google Patents

Abstract

PURPOSE:To eliminate an unnecessary fluid space in the interior of a rotor chamber, reduce fluid friction loss and improve the efficiency of a motor by extending the rotor side end parts of bearing housings in such a manner as to approach both ends of a rotor to reduce a fluid space except a clearance between a stator and a rotor in the interior of the rotor. CONSTITUTION:Bearings 30, 32 are supported on bearing housings 26, 28 at both end areas of a canned motor part 12, a rotor shaft 22 is rotatably supported by the bearings 30, 32, some of a pump handling liquid is introduced into the canned motor part 12 to lubricate the bearings 30, 32, and the pump handling liquid is supplied between a stator 14 and a rotor 16 to cool the motor part 12. The rotor side end parts of bearing housings 26, 28 are extended to approach both ends of the rotor 16, thereby reducing a fluid space except a clearance between the stator 14 and the rotor 16 in the interior of the rotor chamber. Further, a ring-like seal member 60 is disposed between the rotor side end parts of the bearing housings 26, 28 and the stator 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canned motor pump in which a canned motor part and a pump part are coaxially coupled, and a part of pump handling liquid is introduced into the canned motor part to lubricate a bearing and cool the motor. In particular, by reducing unnecessary space in the rotor chamber of the canned motor part,
The present invention relates to a canned motor pump that can secure a minimum required flow path, reduce fluid friction loss of fluid flowing in a rotor chamber, and improve motor efficiency.

[0002]

2. Description of the Related Art Generally, a canned motor pump is shown in FIG.
Further, as shown in FIG. 4, it comprises a pump unit 10 and a canned motor unit 12, the canned motor unit 12 has a stator 14 and a rotor 16, and the stator 14 has an inner peripheral portion hermetically sealed by a stator can 18. The rotor 16 has a structure in which the outer peripheral portion is sealed by a rotor can 20. Further, the rotor 16 rotatably supports the rotor shaft 22 at both ends of the motor casing 24 by bearings 30 and 32 supported by bearing housings 26 and 28, respectively, and a part of the handling liquid introduced into the pump portion 10 is supported. It is configured to circulate in the canned motor portion 12 defined by the stator can 18 and the rotor can 20 via the bearings 30 and 32.

In the configuration shown in FIG. 3, the discharge pipe 34 of the pump unit 10 is used as a liquid introducing unit and a liquid discharging unit for circulating a part of the liquid handled by the pump unit 10 into the canned motor unit 12. An external pipe 36 is drawn out from a part, and is connected to the rear bearing housing 28 so as to communicate therewith to introduce a part of the liquid to be handled into the canned motor part 12. Shaft penetrating portion gap 40 provided in partition wall portion 38 of motor portion 12
Also, the liquid is circulated to the suction side of the pump unit 10 through the balance hole 44 of the impeller 42.

Further, in the structure shown in FIG. 4, a part of the liquid to be handled is introduced into the front rotor chamber 48 on the discharge side of the pump portion 10 through the through hole 46 provided in the partition wall portion 38, Further, from the inside of the canned motor unit 12, the rear rotor chamber 5
The liquid is circulated to the suction side of the pump unit 10 through the passage 52 that passes through the rotor shaft 22 through the zero and rear bearing housings 28.

[0005]

In the conventional canned motor pump described above, however, the liquid flowing in the space inside the rotor chamber of the canned motor portion is forced to be rotated by the rotation of the rotor. Fluid friction loss occurred in the space, which was a major factor in reducing pump efficiency. However, in the conventional canned motor pump, almost no consideration has been given to this fluid friction loss, and no specific proposal has been made to improve the internal structure of the canned motor part from this viewpoint.

This kind of fluid friction loss is caused by the fact that when an object rotates in a container filled with the fluid, for example, the fluid becomes viscous, and the fluid also rotates as the object rotates. Friction occurs between the stationary side of the and the fluid that started to rotate. Further, in this case, it is apparent that pressure is also generated between the fluids, the fluids generate a swirl flow, and fluid friction loss occurs. Then, the fluid friction loss Pd at this time
Is expressed by the following equation. ^{Pd = k · r · u 3} · D (D + 5b) where, k: coefficient, r: specific gravity of the fluid, u: circumferential velocity, D: outer diameter, b: shows the width.

As is clear from the above equation, when the peripheral speed is fast (that is, the rotational speed is large) and the outer diameter is large,
Fluid friction loss will be significantly higher. Therefore, when the canned motor pump is rotated at a high speed or the output is increased (that is, the outer diameter of the rotor is increased), the fluid friction loss increases excessively, which makes it difficult to operate the pump substantially. .

Therefore, an object of the present invention is to eliminate unnecessary fluid space in the rotor chamber in the canned motor section and to secure only a minimum flow passage space, thereby reducing fluid friction loss and improving motor efficiency. It is to provide a canned motor pump capable of improving

[0009]

In order to achieve the above object, a canned motor pump according to the present invention comprises a pump part and a canned motor part, and bearing housings are provided at both ends of the canned motor part, respectively. The bearings are supported, the rotor shaft is rotatably supported by these bearings, a portion of the pump handling liquid is introduced into the canned motor section, and the pump handling liquid lubricates the bearings and the stator pumps the handling liquid. And a rotor, the canned motor pump is configured to cool the motor part. In the canned motor pump, the rotor housing side end of the bearing housing is extended so as to approach both ends of the rotor. It is characterized in that it is configured to reduce the fluid space in the rotor chamber excluding the gap.

In the above-mentioned canned motor pump, if a seal member is provided between the rotor-side end portion of the bearing housing extending toward both ends of the rotor and the stator, and the outer peripheral portion of the bearing housing is liquid-sealed. It is suitable.

Further, a part of the pump handling liquid is introduced into the rear bearing housing of the canned motor portion from the discharge pipe of the pump portion through the external pipe, and then from the rear bearing housing to the rear portion of the rear bearing and the rotor shaft. It is guided to the rear end of the rotor through the drilled bypass passage and led out to the front end of the rotor through the space between the stator and the rotor. It can be configured to circulate to the suction side of the pump section via each of them.

Further, a part of the pump handling liquid is introduced from the discharge side of the pump portion to the front end portion of the rotor through a bypass hole provided in the front bearing housing, and then the suction portion of the pump portion is sucked through the front bearing. Circulate to the side,
It is led out to the rear end of the rotor through a space between the stator and the rotor, and is guided into the rear bearing housing through a bypass hole provided in the rear bearing and the rear bearing housing, and further through a passage passing through the rotor shaft. It may be configured to circulate to the suction side of the pump unit.

[0013]

According to the canned motor pump of the present invention, in the canned motor portion, the rotor housing-side end portion of the bearing housing that supports the bearing that supports the rotor shaft is extended so as to approach both ends of the rotor. By configuring to reduce the fluid space in the rotor chamber excluding the gap between the rotor and the rotor, unnecessary fluid space in the rotor chamber is eliminated, and only the minimum required flow passage space is secured to reduce fluid friction loss. The motor efficiency can be improved.

[0014]

Embodiments of the canned motor pump according to the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic side sectional view showing an embodiment of a canned motor pump according to the present invention. For convenience of explanation, the same components as those of the conventional canned motor pump shown in FIGS. 3 and 4 described above are designated by the same reference numerals, and detailed description thereof will be omitted. That is,
In FIG. 1, reference numeral 10 indicates a pump portion, and 12 indicates a canned motor portion. The pump unit 10 and the canned motor unit 12 are connected by an adapter 54.

The pump portion 10 is provided with a suction pipe 58 and a discharge pipe 34 which communicate with the inside of a pump chamber 56 in which the impeller 42 is provided, and the impeller 42 is attached to the extended end portion of the rotor shaft 22 of the canned motor portion 12. Has been.

On the other hand, the canned motor portion 12 comprises a stator 14 and a rotor 16, the rotor shaft 22 is supported by a front bearing 30 and a rear bearing 32, respectively, and these bearings 30 and 32 are front bearing housings. 26 and rear bearing housing 28
Supported by and. However, in the present embodiment, the rotor-side ends of the bearing housings 26 and 28 are extended so as to approach both ends of the rotor 16, respectively, so as to minimize the fluid space conventionally formed as the rotor chamber. To configure. Also in this case,
Ring-shaped seal members 60, 6 are provided between the rotor 14 and the rotor-side end portions of the bearing housings 26, 28 that extend toward both ends of the rotor 16, respectively.
0 is set. Thereby, the bearing housing 2
The space formed between the stators 6 and 28 and the stator 14 can be liquid-sealed to further reduce the fluid space in the rotor chamber.

Therefore, in this embodiment, a part of the pump handling liquid is provided in the rear bearing housing 28 of the canned motor portion 12 through the external pipe 36 from the discharge pipe 34 of the pump portion 10 as in the conventional case. It is configured to be introduced into the fluid chamber 62. Then, a part of the handled liquid introduced into the fluid chamber 62 directly guides the rear bearing 32 and is guided to the rear end space of the rotor 16, while the other part thereof is guided to the rear portion of the rotor shaft 22. The rotor 16 is configured to meet in the rear end space of the rotor 16 via a bypass passage 64. Next, this liquid to be handled is led to the front end space of the rotor 16 through the space between the stator 14 and the rotor 16, during which cooling of the motor is achieved. After that, a part of the handled liquid directly lubricates the front bearing 30,
It circulates to the suction side of the pump unit 10 through the shaft penetration gap 40 provided in the partition wall 38 of the pump unit 10 and the canned motor unit 12 and the balance hole 44 of the impeller 42. The other part circulates to the suction side of the pump part 10 via the bypass passages 66 formed in the front part of the rotor shaft 22.

In this way, according to the canned motor pump of this embodiment, the fluid space in the rotor chamber is set to the necessary minimum as compared with the conventional canned motor pump, and the pump having a very small fluid friction loss. A highly efficient canned motor pump can be obtained.

FIG. 2a is a schematic side sectional view showing another embodiment of the canned motor pump according to the present invention. Figure 2b
Is an example in which the thrust washer is arranged in contact with the rotor to further enhance the effect. In the present embodiment, the present invention is applied to the canned motor pump shown in FIG.
Therefore, also in this embodiment, the bearing housings 26, 28 and the structure related thereto are basically the same as those in the embodiment shown in FIG. Therefore, the same components as those shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

However, in the present embodiment, the means for introducing and discharging the handled liquid to the canned motor portion 12 is slightly improved over the conventional structure shown in FIG. That is, when introducing the pump handling liquid, on the discharge side of the pump portion 10, directly into the front end space of the rotor 16 through the through hole 46 provided in the partition wall portion 38 and the bypass hole 68 provided in the front bearing housing 26. Configure to install. In this way, a part of the handled liquid introduced into the front end space of the rotor 16 directly lubricates the front bearing 30, and the shaft penetrates through the partition wall 38 of the pump unit 10 and the canned motor unit 12. After passing through the gap 40 between the parts and the balance hole 44 of the impeller 42, the pump part 1
Circulate to the suction side of 0. The other part is led out to the front end space of the rotor 16 through the space between the stator 14 and the rotor 16, during which cooling of the motor is achieved. Then, a part of the handled liquid directly lubricates the rear bearing 32 and is introduced into the fluid chamber 62 provided in the rear bearing housing 28. The other part merges in the fluid chamber 62 via a bypass hole 70 provided in the rear bearing housing 28. The handling liquids thus merged circulate to the suction side of the pump unit 10 via the passage 52 penetrating the rotor shaft 22.

Also in the canned motor pump of the present embodiment constructed as described above, the fluid space in the rotor chamber is set to a necessary minimum as in the case of the above-mentioned embodiment, so that the fluid friction loss is extremely small and the pump efficiency is improved. An excellent canned motor pump can be obtained.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit thereof.

[0024]

As described above, the canned motor pump according to the present invention comprises the pump part and the canned motor part, and the bearing housings are provided at both ends of the canned motor part to support the bearings. Rotatably supports the rotor shaft, introduces part of the pump handling liquid into the canned motor section, lubricates the bearings with this pump handling liquid, and supplies this pump handling liquid between the stator and rotor. In the canned motor pump configured to cool the motor part by extending the rotor side end part of the bearing housing so as to approach both ends of the rotor respectively, fluid in the rotor chamber excluding the gap between the stator and the rotor Minimize the fluid space in the rotor chamber by configuring it to reduce space Rukoto can, significantly reduce the fluid friction losses of the rotor, the pump efficiency can be easily improved. Therefore, the canned motor pump of the present invention not only enables high speed operation, but also provides a small canned motor pump having excellent pump efficiency.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view showing an embodiment of a canned motor pump according to the present invention.

FIG. 2 is a schematic side sectional view showing another embodiment of the canned motor pump according to the present invention.

FIG. 3 is a schematic side sectional view showing a configuration example of a conventional canned motor pump corresponding to FIG.

FIG. 4 is a schematic side sectional view showing a configuration example of a conventional canned motor pump corresponding to FIG.

[Explanation of symbols]

 10 pump part 12 canned motor part 14 stator 16 rotor 18 stator can 20 rotor can 22 rotor shaft 24 motor casing 26 front bearing housing 28 rear bearing housing 30 front bearing 32 rear bearing 34 discharge pipe 36 external piping 38 bulkhead 40 shaft penetration Part gap 42 Impeller 44 Balance hole 46 Through hole 48 Front rotor chamber 50 Rear rotor chamber 52 Passage 54 Adapter 56 Pump chamber 58 Suction pipe 60 Seal member 62 Fluid chamber 64, 66 Bypass passage 68, 70 Bypass hole

Claims (4)

[Claims] 1. A pump unit and a canned motor unit, bearing housings are provided at both ends of the canned motor unit to support the bearings, respectively, and the rotor shaft is rotatably supported by these bearings, and a pump handling liquid In a canned motor pump configured to introduce a part thereof into the canned motor unit to lubricate the bearing with this pump handling liquid and to supply this pump handling liquid between the stator and the rotor to cool the motor unit. A canned motor pump characterized in that the rotor-side end portion of the bearing housing is extended so as to come close to both ends of the rotor, respectively, to reduce the fluid space in the rotor chamber excluding the gap between the stator and the rotor. . 2. A bearing member is provided with a seal member between the rotor-side end portion of each of the bearing housings, which extends so as to approach both ends of the rotor, and the stator, and the outer peripheral portion of the bearing housing is liquid-sealed. Canned motor pump. 3. A part of the pump handling liquid is introduced into the rear bearing housing of the canned motor part from the discharge pipe of the pump part through an external pipe, and then from the rear bearing housing to the rear part of the rear bearing and the rotor shaft. Guide to the rear end of the rotor via the bypass passage that has been drilled,
It is configured to be led out to a front end portion of the rotor through a space between the stator and the rotor, and further circulate to the suction side of the pump portion via a front bearing and a bypass passage formed in the front portion of the rotor shaft. The canned motor pump according to item 1 or 2. 4. A part of the pump handling liquid is introduced from the discharge side of the pump portion to the front end portion of the rotor through a bypass hole provided in the front bearing housing, and then suctioned to the pump portion via the front bearing. Side of the rotor, and is led to the rear end of the rotor through the space between the stator and the rotor, and guided to the rear bearing housing through the rear bearing and the bypass hole provided in the rear bearing housing. The canned motor pump according to claim 1 or 2, wherein the canned motor pump is configured to circulate to a suction side of a pump portion through a passage that passes through the pump.