JPH09317681A - Canned motor pump coupling method - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] A canned motor pump in which a dangerous speed of a shaft is set to a high value to enable stable operation even at high speed rotation, and moreover, easy assembly and disassembly of a canned motor unit and a pump unit. Provides a combination method of. In a canned motor pump including a canned motor unit 10 and a pump unit 12, a rotor shaft 14 and an impeller rotating shaft 34 of the canned motor unit are separately configured, and the rotor shaft 14 and the impeller rotating shaft are separately formed. 34 and a flexible coupling means 36,
A pump unit 1 as a load unit for the canned motor unit 10.
Connect the two together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling system for a canned motor pump, and in particular, a rotor shaft and a impeller rotating shaft as a load in a high speed canned motor pump exceeding 3,600 rpm are separately constructed. The present invention relates to a canned motor pump coupling system in which the dangerous speed of shaft rotation can be adjusted by coupling the above-mentioned with a required coupling means to avoid danger.

[0002]

2. Description of the Related Art A canned motor pump generally comprises a canned motor part and a pump part. The canned motor part has a stator and a rotor. The stator has an inner peripheral part hermetically sealed with a stator can, and the rotor has an outer peripheral part. Is composed of a rotor can and is hermetically sealed. The rotor has a rotor shaft rotatably supported by bearings supported at both ends of a motor casing, and a part of the liquid to be introduced into the pump portion is defined by the stator can and the rotor can via the bearings. It is configured to circulate in the canned motor unit. Liquid introducing means and liquid discharging means for circulating a part of the handled liquid in the pump portion into the canned motor portion are provided in a part of the motor casing, respectively.

The canned motor pump thus constructed is used as a pump for various chemical plants because it introduces a fluid into the rotor chamber in the canned motor portion to lubricate the bearings and cool the motor. ing.

However, in recent years, there has been an increasing demand for high speed operation of this type of canned motor pump as its application is expanded. However, in the conventional canned motor pump, the impeller is directly coupled to one end of the rotor shaft, and the impeller and the rotor shaft perform the same rotation. Therefore, for example, high speed rotation exceeding 3,600 rpm is performed. In this case, in particular, the motor efficiency is reduced due to fluid friction loss in the canned motor part, the heat generation of the stator is increased, or the life of the bearing is shortened.
There are many problems to be solved.

That is, since the rotor chamber of the canned motor section is filled with liquid, when the rotor rotates,
The fluid friction loss is significantly increased as compared with a normal motor.
Therefore, the motor efficiency is reduced and the heat generation of the stator is increased. Therefore, in order to reduce the heat generation of the stator, it is necessary to increase the outer diameter of the motor. However, in this case, the peripheral speed of the rotor is increased and the fluid friction loss is further increased.

[0006]

However, in the conventional canned motor pump, since the rotor shaft of the canned motor part and the impeller rotating shaft of the pump part are integrally formed, there is a danger associated with the rotation of the rotor shaft. In order to avoid the speed, there are many dimensional restrictions such as the thickness and length of the rotor shaft, and the shape and weight of the impeller of the motor unit attached to the tip of the rotor shaft.

For example, in a high-speed motor exceeding 3,600 rpm, the fluid friction loss due to the rotation of the rotor remarkably increases, so the ratio L / D between the length L of the rotor core and the outer diameter D of the rotor becomes 5 or more. There is no choice but to use an elongated rotor structure. Therefore, the span between the bearings that support the rotor becomes significantly longer, and the design limitation that the shaft diameter cannot be made too large affects the avoidance of critical speeds and ensuring the reliability of bearings that support the load from the pump part. And the like are likely to cause problems.

The critical speed of the rotating shaft is determined by the size of the diameter of the rotating shaft, the bearing spacing of the bearing, and the weight of the rotating shaft. Generally, when the rotating frequency of the rotating shaft increases, This is a speed at which there is a risk that the resonance phenomenon, that is, the amplitude of vibration rapidly increases in accordance with the natural frequency of the rotating system, and thereby the structure is damaged.

Therefore, if the structure in which the pump portion is separated and the load generated by the pump portion is supported by the bearing provided on the pump portion side is adopted, the restrictions imposed by the pump portion are eliminated, so that the rotor Great effects can be expected in avoiding critical speeds and improving bearing reliability. That is, in this case, the pump portion can significantly reduce the span between the bearings in view of its structure and shape, so that a high critical speed can be taken even if the shaft diameter is small, and the bearing peripheral speed is also high for the bearing. Can be made smaller, so that the load condition can be improved. However, in the conventional canned motor pump, as described above, there is no special requirement, and for convenience of manufacturing, the pump part, particularly the impeller rotary shaft is molded and assembled independently of the canned motor part. The structure of combining these at times is
Not implemented at all.

Therefore, an object of the present invention is to set the critical speed of the shaft to a high value, to enable stable operation even at high speed rotation, and to facilitate the assembly and disassembly of the canned motor part and the pump part. It is to provide a coupling method for a motor pump.

[0011]

In order to achieve the above-mentioned object, the canned motor pump coupling system according to the present invention comprises:
In a canned motor pump including a canned motor unit and a pump unit, the rotor shaft and the impeller rotation shaft of the canned motor unit are separately configured, and the rotor shaft and the impeller rotation shaft are connected via a flexible coupling means. It is characterized in that the pump unit as a load unit is integrally connected to the canned motor unit.

In this case, the flexible coupling means is composed of a spline coupling, and the shaft ends of the rotor shaft and the impeller rotating shaft that are opposed to each other are coupled by a spline coupling connection that is coaxially fitted to each other. Can be

The end of the rotor shaft is formed as a shaft hole having a spline of a vertical groove formed on the inner surface thereof, and the end of the impeller rotating shaft is provided with a spline of the vertical groove on the outer surface fitted to the shaft hole. In addition, in the spline coupling connecting portion between the rotor shaft and the impeller rotating shaft, a required gap is provided at a fitting portion of each shaft, and a through hole communicating with the gap is provided on the outer periphery of the rotor shaft. A part may be provided to allow a part of the pump handling liquid to flow from the impeller rotation shaft side to the rotor shaft side.

As an alternative, the flexible coupling means is composed of a magnet coupling, and the opposite shaft ends of the rotor shaft and the impeller rotation shaft are coupled to each other by a magnetic coupling connection that coaxially and non-contact fit with each other. It can be configured to.

The end portion of the rotor shaft is formed as a shaft hole having a magnet for generating a rotating magnetic field on the inner surface thereof, and the end portion of the impeller rotation shaft is fitted into the shaft hole in a non-contact manner so as to be magnetic. A magnet that produces a coupling action is formed, and at the magnet coupling connection portion between the rotor shaft and the impeller rotation shaft, a communication is formed on the outer periphery of the rotor shaft so as to communicate with a gap formed in the non-contact fitting portion of each shaft. A hole may be provided to allow a part of the pump handling liquid to flow from the impeller rotating shaft side to the rotor shaft side.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a coupling system for a canned motor pump according to the present invention will be described in detail with reference to the drawings.

1 and 2 are cross-sectional views of a canned motor pump embodying the coupling method of the present invention.
These canned motor pumps are basically composed of a canned motor unit 10 and a pump unit 12. The canned motor unit 10 includes a rotor 16 fixed to a rotor shaft 14 and a stator 2 fixed to a motor casing 18.
0, which are liquid-tightly covered by a rotor sleeve 22 and a stator liner 24, respectively. The rotor shaft 14 has bearings 26, 2 on both sides thereof.
It is supported by 6.

The pump section 12 comprises an impeller 30 supported by an impeller rotating shaft 34, and a pump casing 32 accommodating the impeller 30. The impeller rotating shaft 34 is supported by bearings 28, 28.

The rotor shaft 14 of the canned motor unit 10 and the impeller rotating shaft 34 of the pump unit 12 are
It couple | bonds via the flexible coupling means 36 mentioned later.

In such a structure, when a three-phase AC power source is supplied from the terminal box 38 to the stator 20, the stator 2
At 0, a rotating magnetic field is generated, and the rotor 16 is rotationally driven to perform pump operation. In addition, during this pump operation,
A part of the pump handling liquid circulates to the pump unit 10 through the internal and external circulation pipes 40 of the canned motor unit 10, thereby cooling the canned motor unit 10 and lubricating the bearings 26, 28.

Next, specific examples of the coupling system of the canned motor pump according to the present invention will be described with reference to the drawings.

[0022]

Embodiment 1 FIG. 1 is a schematic side sectional view showing an embodiment of a coupling system for a canned motor pump according to the present invention.
That is, in this embodiment, a spline coupling is used as a coupling means for connecting the rotor shaft 14 of the canned motor unit 10 and the impeller rotating shaft 34 of the pump unit 12. The rotor shaft 14 and the impeller rotating shaft 34 are made of stainless steel, respectively.

However, in this embodiment, the rotor shaft 1
4 and the impeller rotating shaft 34 are formed separately, and the opposite ends of the rotor shaft 14 and the impeller rotating shaft 34 are spline-coupling connected to each other so as to be coaxially fitted to each other. In this case, the end portion of the rotor shaft 14 is formed as a shaft hole 44 in which the spline of the vertical groove 42 is provided on the inner surface, and the end portion of the impeller rotating shaft 34 is formed on the outer surface fitted to the shaft hole 44. By forming the spline 42 and inserting the end of the impeller rotating shaft 34 into the shaft hole 44 of the rotor shaft 14, both shafts can be locked in the rotational direction to be connected.

Although not shown, the rotor shaft 1
4 and a spline coupling connecting portion between the impeller rotating shaft 34, a fitting gap between the shafts 14 and 34 is provided with a required gap, and a through hole 46 communicating with the gap is provided on the outer periphery of the rotor shaft 14. To provide. As a result, during pump operation, a part of the pump handling liquid is circulated from the impeller rotation shaft 34 side to the rotor shaft 14 side and circulated to the pump unit 10 through the inside of the canned motor unit 10 and the external circulation pipe 40. be able to. In this case, the canned motor part 10 can be cooled as described above, but at this time, a part of the pump handling liquid also flows into the gap of the spline coupling connection part to cool it. can do.

[0025]

Embodiment 2 FIG. 2 is a schematic side sectional view showing another embodiment of the coupling system of the canned motor pump according to the present invention. That is, in the present embodiment, the canned motor unit 1
0 rotor shaft 14 and impeller rotating shaft 3 of pump unit 12
A magnet coupling is used as a coupling means for connecting with No. 4.

However, in this embodiment, the rotor shaft 1
4 and the impeller rotation shaft 34 are formed separately, and the opposite ends of the rotor shaft 14 and the impeller rotation shaft 34 are magnet coupling connection configurations in which they are coaxially fitted to each other in a non-contact manner. . In this case, the end of the rotor shaft 14 is formed as a shaft hole 50 having a magnet 48a for generating a rotating magnetic field on its inner surface, and the end 52 of the impeller rotating shaft 34 is fitted in the shaft hole 50 in a non-contact manner. To form a magnet 48b that produces a magnetic coupling action, and to form the shaft hole 50 of the rotor shaft 14.
By inserting the end portion 52 of the impeller rotation shaft 34 into the shaft, both shafts can be connected and configured so as to be coaxially rotatable.

Further, in the magnet coupling connecting portion between the rotor shaft 14 and the impeller rotating shaft 34, the outer periphery of the rotor shaft 14 communicates with the gap 56 formed in the non-contact fitting portion of each shaft 14, 34. A through hole 54 is provided. As a result, during pump operation, a part of the pump handling liquid is circulated from the impeller rotation shaft 34 side to the rotor shaft 14 side and circulated to the pump unit 10 through the inside of the canned motor unit 10 and the external circulation pipe 40. be able to. Even in this case, the canned motor portion 10 can be cooled as described above. At this time, however, a part of the pump handling liquid also flows into the gap 56 of the magnet coupling connection portion. Can be cooled.

As described above, according to the coupling system of the canned motor pump of the present invention, the rotor shaft 14 and the impeller rotating shaft 34 are formed as separate members, and these are connected by a flexible coupling to form a rotating shaft. It is possible to set a high dangerous speed of, and thus stable operation can be easily realized by rotating the canned motor pump at high speed.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and many design changes can be made without departing from the spirit of the present invention. For example, although the canned motor pump has been described as an example in the above-described embodiments, the coupling method of the present invention can be effectively applied not only to the pump but also to a blower or the like as the load of the canned motor. Also,
Although spline coupling and magnet coupling are exemplified as the coupling means, the coupling means is not limited to these, and various known coupling devices can of course be adopted as long as they can achieve flexible coupling. Is.

[0030]

As described above, in the canned motor pump coupling method according to the present invention, in the canned motor pump including the canned motor portion and the pump portion, the rotor shaft and the impeller rotation shaft of the canned motor portion are connected to each other. By configuring each separately, by coupling the rotor shaft and the impeller rotation shaft via a flexible coupling means, by integrally connecting the pump portion as a load portion to the canned motor portion, By setting the critical speed of the axis high, stable operation is possible even at high speeds,
Moreover, the canned motor portion and the pump portion can be easily assembled and disassembled.

[Brief description of drawings]

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

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

[Explanation of symbols]

 10 canned motor part 12 pump part 14 rotor shaft 16 rotor 18 motor casing 20 stator 22 rotor sleeve 24 stator liner 26 bearing 28 bearing 30 impeller 32 pump casing 34 impeller rotary shaft 36 coupling means 38 terminal box 40 external circulation pipe 42 vertical groove 44 Shaft hole 46 Through hole portions 48a, 48b Magnet 50 Shaft hole 52 End portion 54 Through hole portion 56 Gap

Claims (7)

[Claims] 1. A canned motor pump comprising a canned motor unit and a pump unit, wherein the rotor shaft and the impeller rotation shaft of the canned motor unit are separately configured, and the rotor shaft and the impeller rotation shaft are flexible. A coupling system for a canned motor pump, characterized in that the canned motor unit is integrally coupled with a pump unit as a load unit by means of coupling means. 2. The flexible coupling means is composed of a spline coupling, and the shaft ends of the rotor shaft and the impeller rotating shaft that are opposed to each other are connected by a spline coupling connection that is coaxially fitted to each other. Item 2. A canned motor pump coupling method according to Item 1. 3. An end portion of the rotor shaft is formed as a shaft hole having a spline of a vertical groove formed on an inner surface thereof, and a spline of the vertical groove is formed on an outer surface of the impeller rotating shaft fitted to the shaft hole. The canned motor pump coupling method according to claim 2, which is formed. 4. A spline coupling connecting portion between a rotor shaft and an impeller rotating shaft is provided with a required gap at a fitting portion of each shaft, and a through hole communicating with the gap is provided on an outer periphery of the rotor shaft. The canned motor pump coupling method according to claim 3, wherein a part of the pump handling liquid is circulated from the impeller rotation shaft side to the rotor shaft side. 5. The flexible coupling means is composed of a magnet coupling, and the opposite shaft ends of the rotor shaft and the impeller rotation shaft are coupled to each other by a magnetic coupling connection that coaxially and non-contactly fits each other. The canned motor pump coupling method according to claim 1. 6. An end portion of the rotor shaft is formed as a shaft hole provided with a magnet for generating a rotating magnetic field on an inner surface, and an end portion of the impeller rotation shaft is magnetically coupled by non-contact fitting with the shaft hole. The canned motor pump coupling method according to claim 5, wherein a magnet that produces an action is formed. 7. A magnet coupling connecting portion between a rotor shaft and an impeller rotating shaft, wherein a through hole portion communicating with a gap formed in a non-contact fitting portion of each shaft is provided on an outer periphery of the rotor shaft, 7. The canned motor pump coupling system according to claim 6, wherein a part of the pump handling liquid is circulated from the impeller rotating shaft side to the rotor shaft side.