JP3942428B2 - Canned motor pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a canned motor pump, and more particularly to an all-around canned motor pump in which an annular passage is formed in the outer periphery of a canned motor to provide an annular space through which a liquid to be handled flows.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known an all-around flow type pump in which an annular flow path is formed in an outer peripheral portion of a motor so that a handling liquid flows. Such a full-circumferential pump is a type of canned motor pump, in which a motor frame that houses a motor stator and an annular space that is provided outside the motor frame and through which the handling fluid flows are formed. And an outer cylinder. A canned motor is disposed in the motor frame, and the rotor is rotatably supported by a bearing.
[0003]
In such a full-circumference type canned motor pump, after handling liquid pressurized in the impeller is guided to the annular space, it is discharged from the discharge port of the discharge-side casing, and the canned motor is cooled by the handling liquid flowing in the annular space. is doing. In addition, a part of the handling liquid is circulated through a small gap between the rotor and the stator to cool the motor and lubricate the bearing.
[0004]
[Problems to be solved by the invention]
As described above, in the all-around flow type canned motor pump, the canned motor is cooled by the handling liquid flowing in the annular space, and a part of the handling liquid is circulated in a small gap between the rotor and the stator. Cooling and bearing lubrication are performed. However, in a pump for pure water use, fine particles and eluted ions accumulate around the rotor and flow out in large quantities at a certain point in time, so that the pure water level of the handling liquid discharged from the discharge port cannot be secured. It may become. In addition, when the handling liquid contains small bubbles or dissolved gas, the air stays around the rotor due to the centrifugal separation action with the passage of the continuous operation time of the pump, and the bearing may be damaged due to poor lubrication.
[0005]
The present invention has been made in view of such problems of the prior art, and can prevent accumulation of fine particles and eluted ions and retention of air around the rotor. Even if the bearing is damaged, An object of the present invention is to provide a canned motor pump capable of preventing a broken bearing piece from being mixed into a handling liquid discharged from the pump.
[0006]
[Means for Solving the Problems]
In order to solve such a problem in the prior art, one aspect of the present invention is that a fluid to be handled is provided between a motor frame in which a motor stator is accommodated and a motor frame provided outside the motor frame. A canned motor pump having an outer cylinder that forms an annular space that flows, and at one end of the main shaft, a suction-side casing that guides the handling liquid from the suction port to the annular space, and pressurizes the handling liquid An impeller is provided, and a discharge-side casing is provided at the other end of the main shaft to guide the handling liquid from the annular space to the discharge port, and is separated from the discharge space communicating with the discharge port of the discharge-side casing. forming a rotor chamber, a drain pipe to the pumped fluid in the rotor chamber separately discharged from the pumped fluid in the discharge space is connected to the rotor chamber, the rotor chamber, the other end of the spindle and the discharge A tubular member that connects the inner surface of the casing is formed by a part of the inner surface of the discharge side casing, the cylindrical member, said the abutting via an elastic body to the inner surface of the discharge-side casing It is a canned motor pump.
[0007]
With such a configuration, fine particles and eluted ions accumulated around the rotor are discharged to the outside separately from the handling liquid in the discharge space, so the pure water level of the handling liquid discharged from the discharge port of the discharge side casing can be adjusted. Can be secured. Further, since air is prevented from staying around the rotor, damage due to poor lubrication of the bearing can be prevented. Furthermore, even if these bearings are damaged, it is possible to prevent the broken pieces of the bearing from being mixed into the handling liquid discharged from the discharge port of the discharge side casing.
[0009]
A preferred embodiment of the present invention is characterized in that a small-diameter hole is formed in the outer peripheral surface of the cylindrical member so as to communicate the internal space of the rotor chamber with the discharge space. The air in the rotor chamber can be extracted through the small-diameter hole when the pump is installed or water is filled.
[0011]
One preferable aspect of the present invention is characterized in that the drain pipe is connected to a suction port of the suction side casing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a canned motor pump according to the present invention will be described in detail with reference to FIGS. 1 and 2. 1 and 2, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.
[0013]
FIG. 1 is a longitudinal sectional view showing a canned motor pump according to a first embodiment of the present invention. As shown in FIG. 1, the full-circumference type canned motor pump according to the present embodiment is handled between a motor frame 1 that houses a motor stator therein and a motor frame 1 that is provided outside the motor frame 1. And an outer cylinder 2 forming an annular space 50 through which fluid flows. The motor frame 1 and the outer cylinder 2 are formed from stainless cast steel so as to be integrated via ribs 3 by a lost wax casting method.
[0014]
A stator 4 is shrink-fitted inside the motor frame 1, and a motor frame side plate 5 is hermetically welded to the axially open end of the motor frame 1. A stator can 6 made of a thin stainless steel plate is fitted on the inner periphery of the stator 4, and the stator can 6 is hermetically welded to the motor frame 1 and the motor frame side plate 5.
[0015]
A rotor 7 is rotatably accommodated inside the stator 4. The rotor 7 is fixed to the main shaft 10 by shrinkage fitting, and the rotor can 11, the rotor side plates 12 and 12, and the main shaft 10 are hermetically welded to protect the rotor 7 from corrosion by the handled fluid. The material of the rotor can 11, the rotor side plates 12 and 12, and the main shaft 10 is stainless steel.
[0016]
The main shaft 10 is supported at both ends by bearings installed on the motor frame 1 and the motor frame side plate 5, and an impeller 13 is fixed to one end of the main shaft 10. The impeller 13 is a cast molded product made of cast stainless steel.
[0017]
Next, the bearing peripheral part on the side opposite to the thrust load provided on the side opposite to the impeller 13 will be described. The bearing bracket 20 is provided with a radial bearing 21 and a fixed-side thrust bearing 22. The end face of the radial bearing 21 is also provided with a function as a fixed-side thrust bearing that supports a reverse thrust load that occurs infrequently.
[0018]
On both sides of the radial bearing 21 and the fixed-side thrust bearing 22, a rotation-side forward thrust bearing 23 that supports a thrust load in the forward direction and a rotation-side reverse thrust bearing 24 that supports a thrust load in the reverse direction are provided. Yes. The two thrust bearings 23 and 24 are shrink-fitted and fixed to the thrust disks 25 and 26, respectively. The two thrust disks 25 and 26 sandwich the radial bearing and the sleeve 27 constituting the sliding portion, and the main shaft 10 It is fixed by a double nut 28 provided at the end of the.
[0019]
The bearing bracket 20 is inserted into a shell 5a provided on the motor frame side plate 5 via a gasket 30 made of an elastic material. The bearing bracket 20 is in contact with the motor frame side plate 5 through the gasket 30. The material of the thrust bearings 22, 23, 24, the radial bearing 21 and the sleeve 27 is silicon carbide (SiC) which is a kind of ceramic material, and the material of the bearing bracket 20 and the thrust disks 25, 26 is stainless steel. .
[0020]
Next, the bearing peripheral portion on the thrust load side provided on the impeller side will be described. A radial bearing 32 is provided on the bearing bracket 31 and is inserted into the canopy 1a of the motor frame 1 via an O-ring 33 made of an elastic material. A radial bearing 32 and a sleeve 34 constituting a sliding portion are fixed by a nut 36 provided at an end of the main shaft 10 via a washer 35 and an impeller 13.
[0021]
At both end portions in the axial direction of the outer cylinder 2, there are provided candles 2 a, 2 a for securing the coaxiality with the mounting parts and bolt seats 2 b, 2 b for fastening the bolts, via O-rings 38, 38. A suction-side casing 40 and a discharge-side casing 41 made of stainless cast steel are fixed. These casings 40 and 41 are formed from cast stainless steel by a lost wax casting method.
[0022]
A cylindrical member 60 that connects the motor frame side plate 5 and the inner surface of the discharge side casing 41 is provided at the end opposite to the impeller 13. The cylindrical member 60 is in contact with the inner surface of the discharge-side casing 41 via an elastic body 61. A rotor chamber 51 is formed by the cylindrical member 60 and a part of the inner surface of the discharge-side casing 41. The internal space of the rotor chamber 51 is separated from the discharge space 52 communicating with the discharge port 41 a of the discharge side casing 41 by the tubular member 60. In addition, a drain pipe 63 having a valve 62 is connected to the rotor chamber 51.
[0023]
The handling liquid sucked from the suction port 40 a of the suction side casing 40 is boosted by the impeller 13 and then guided to the annular space 50 between the motor frame 1 and the outer cylinder 2. The handling fluid guided to the annular space 50 effectively cools the outer peripheral portion of the stator 4. The handling liquid flowing through the annular space 50 is guided to the discharge side casing 41 through the discharge space 52 and discharged from the discharge port 41 a of the discharge side casing 41.
[0024]
In addition, some of the handled fluids lubricate and cool the bearings 21, 22, 23, 24, 32 and the sleeves 27, 34, and at the same time cool the inner peripheral portion of the stator 4 and the rotor 7, It reaches. The handling liquid in the rotor chamber 51 passes through the drain pipe 63 and is discharged to the outside separately from the handling liquid in the discharge space 52. Accordingly, fine particles and eluted ions accumulated around the rotor are discharged to the outside separately from the handling liquid in the discharge space 52, and the pure water level of the handling liquid discharged from the discharge port 41a of the discharge-side casing 41, etc. Can be secured. Further, since air is prevented from staying around the rotor, the bearings 21, 22, 23, 24, and 32 can be prevented from being damaged due to poor lubrication. Furthermore, even if these bearings are damaged, it is possible to prevent broken bearing fragments from being mixed into the handling liquid discharged from the discharge port 41a of the discharge-side casing 41. It is preferable to adjust the valve 62 of the drain pipe 63 according to the degree of mixing of fine particles and air.
[0025]
Here, small-diameter holes 60a are formed at a plurality of locations in the circumferential direction on the outer peripheral surface of the cylindrical member 60, and air in the rotor chamber 51 is extracted through the small-diameter holes 60a when the pump is installed or water is filled. be able to. Since the hole 60a has a small diameter, fine particles and eluted ions accumulated around the rotor hardly flow out to the discharge space 52 through the small diameter hole 60a, and the discharge side casing 41 discharges as described above. The pure water level of the handling liquid discharged from the outlet 41a can be ensured.
[0026]
In pure water applications, it is often continuously operated non-stop for a long period of time, and air tends to stay around the rotor. Therefore, the all-around canned motor pump according to the present invention is for secondary pure water with a relatively low head. Suitable for applications such as pumps.
[0027]
FIG. 2 is a longitudinal sectional view showing a canned motor pump according to the second embodiment of the present invention. In the present embodiment, the other end of the drain pipe 64 connected to the rotor chamber 51 is connected to the suction port 40 a of the suction side casing 40. The drain pipe 64 is provided with a valve 65 and a connection union 66. In the canned motor pump having such a configuration, the handling liquid discharged from the rotor chamber 51 is again introduced into the pump. For the purpose of preventing poor bearing lubrication due to air retention around the rotor, the other end of the drain pipe 64 connected to the rotor chamber 51 is connected to the suction port 40a of the suction side casing 40 as in this embodiment. Can be connected to.
[0028]
In the present embodiment, air contained in the handling liquid discharged from the drain pipe 64 flows into the pump again, but most of the air is sent to the discharge port 41a through the annular space 50, Since there is little air flowing into the rotor chamber 51 again, there is no adverse effect on the periphery of the rotor.
[0029]
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.
[0030]
【The invention's effect】
As described above, according to the present invention, since the fine particles and eluted ions accumulated around the rotor are discharged to the outside separately from the handling liquid in the discharge space, the handling liquid discharged from the discharge port of the discharge-side casing is removed. A pure water level etc. can be secured. Further, since air is prevented from staying around the rotor, damage due to poor lubrication of the bearing can be prevented. Furthermore, even if these bearings are damaged, it is possible to prevent the broken pieces of the bearing from being mixed into the handling liquid discharged from the discharge port of the discharge side casing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a canned motor pump according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a canned motor pump according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor frame 1a Inro 2 Outer cylinder 2a Inro 2b Bolt seat 3 Rib 4 Stator 5 Motor frame side plate 5a Intro 6 Stator can 7 Rotor 10 Main shaft 11 Rotor can 12 Rotor side plate 13 Impeller 20, 31 Bearing bracket 21 Radial bearing 22 , 23, 24 Thrust bearings 25, 26 Thrust disks 27, 34 Sleeve 28 Double nut 30 Gasket 32 Radial bearing 33, 38 O-ring 35 Washer 36 Nut 40 Suction side casing 40a Suction port 41 Discharge side casing 41a Discharge port 50 Annular space 51 Rotor chamber 52 Discharge space 60 Tubular member 61 Elastic body 62, 65 Valve 63, 64 Drain piping 66 Union

Claims (3)

A canned motor pump comprising: a motor frame that houses a motor stator therein; and an outer cylinder that is provided outside the motor frame and forms an annular space through which a fluid to be handled flows.
At one end of the main shaft, a suction-side casing that guides the handling liquid from the suction port to the annular space, and an impeller that pressurizes the handling liquid,
The other end of the main shaft is provided with a discharge casing that guides the handling liquid from the annular space to the discharge port,
Forming a rotor chamber separated from the discharge space communicating with the discharge port of the discharge-side casing;
A drain pipe for discharging the handling liquid in the rotor chamber separately from the handling liquid in the discharge space is connected to the rotor chamber ,
The rotor chamber is formed by a cylindrical member that connects the other end of the main shaft and the inner surface of the discharge-side casing, and a part of the inner surface of the discharge-side casing,
The canned motor pump , wherein the cylindrical member is in contact with an inner surface of the discharge-side casing via an elastic body . 2. The canned motor pump according to claim 1 , wherein a small-diameter hole is formed in an outer peripheral surface of the cylindrical member to communicate an internal space of the rotor chamber with the discharge space. Canned motor pump according to claim 1 or 2, characterized in that connected to the drain pipe to the suction port of the suction-side casing.

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