JPH0319397B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a submerged type pump having a canned motor pump structure, and particularly relates to a submerged type pump that efficiently supplies circulating fluid of a canned motor while pressurizing it. It is something.

[Conventional technology]

Generally, various submerged pumps are known for discharging liquid from a tank. As this type of submerged pump, a canned motor pump can be used most effectively.

Especially for pumps that handle liquefied gas, etc.
Since the handled liquid introduced into the canned motor is easily gasified, a part of the handled liquid is introduced from the discharge side of the pump into the front motor rotor chamber of the canned motor, and then guided to the rear motor rotor chamber after passing between the stator and rotor. A so-called reverse circulation system is adopted in which the fluid is circulated to the discharge side of the pump. In this case, if the circulating fluid inside the canned motor does not have sufficient pressure, it will easily vaporize inside, creating a dangerous situation. Therefore, an auxiliary impeller must be installed inside the canned motor to pressurize the circulating fluid. has also been proposed.

[Problem to be solved by the invention]

As mentioned above, if the circulating fluid inside the canned motor does not have sufficient pressure and evaporates inside, the bearings of the canned motor will not be lubricated, and this will cause the bearings to rapidly wear out, causing damage to the motor rotor shaft. causes eccentric rotation and the stator can and rotor can come into contact, eventually leading to the can rupture. As a result, if the liquid to be handled is flammable liquefied gas, for example, if the stator can ruptures and vaporized gas flows into the stator chamber, there is a risk of an explosion due to the generation of sparks from the stator coil. There is also a risk of explosion due to the frictional heat of the bearings.

Therefore, as mentioned above, it is effective to provide an auxiliary impeller inside the canned motor to pressurize the circulating fluid, but especially when used as a submerged pump, it is necessary to provide a special auxiliary impeller. There are disadvantages that not only the structure becomes complicated but also the overall configuration becomes large.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a submerged pump that has a simple configuration, can obtain appropriate and efficient circulating fluid inside a canned motor, and can achieve highly safe pump operation.

[Means to solve the problem]

The submerged pump according to the present invention includes a pump section and a canned motor section, and receives a thrust bearing mechanism at the boundary between the pump section and the canned motor section, so that a part of the liquid handled by the pump is transferred through the thrust bearing mechanism and the lower bearing. The pump is introduced into the lower motor rotor chamber through the motor casing, then guided into the upper motor rotor chamber through the space between the internal motor casing and the motor rotor, and further led out through the upper bearing to the pump discharge channel provided outside the canned motor section. In the submerged type pump, the thrust bearing mechanism includes a bearing housing that communicates with the pump discharge flow path and the lower motor rotor chamber, and a thrust bearing that rotates integrally with the motor rotor shaft is installed inside the bearing housing. At the same time, a thrust washer is fixedly arranged opposite to the thrust bearing, and a liquid passage passes through the mounting base of the thrust bearing in the axial direction, and an auxiliary pump discharge opens radially outward from the middle part of the liquid passage. A passage is bored, a diff user part is provided in a part of the pump discharge flow path, and a part of the pump handling liquid is introduced into the bearing housing of the thrust bearing mechanism in a direction perpendicular to the discharge fluid on the downstream side of the diff user part. An opening is provided in a portion of the bearing housing to discharge a portion of the pump handling liquid introduced into the bearing housing from an auxiliary pump discharge passage provided in the thrust bearing to the lower motor rotor chamber. A through hole is provided for the inflow, and an opening is further provided on the upper motor rotor chamber side for allowing the pump handling liquid introduced into the motor rotor chamber to be led out to the pump discharge passage after a part of it lubricates the bearing surface of the upper bearing. It is characterized in that a fixed aperture part is provided in this opening part.

[Effect]

According to the submerged pump according to the present invention,
The thrust bearing, which is installed at the boundary between the pump section and the canned motor section and configured to rotate integrally with the motor rotor shaft, has an auxiliary impeller function.
On the other hand, by providing a fixed throttle part in a part of the rear rotor chamber of the canned motor and configuring it to communicate with the pump discharge flow path, a part of the liquid handled by the pump is pressurized at an appropriate flow rate and introduced into the canned motor. It can be effectively used as internal circulating fluid.

〔Example〕

Next, embodiments of the submerged pump according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a submerged pump employing a canned motor, which is an embodiment of the present invention. That is, this pump includes a pump chamber 10 at its lower end, and a suction port 12 that communicates with this pump chamber 10 is expanded downward. An impeller 14 equipped with an automatic thrust balance mechanism is disposed within the pump chamber 10. Note that an axial flow inducer 16 extending into the suction port 12 is attached to the tip of the impeller 14 . A thrust bearing mechanism 18 is provided adjacent to the pump chamber 10, and a canned motor section 20 is provided above the thrust bearing mechanism 18. Further, a discharge port 22 is opened at the outer circumferential portion of the pump chamber 10, and a pump casing 24 forming the discharge port 22 extends upward, and a casing that surrounds and fixes the thrust bearing mechanism 18 to the inner circumferential portion of the pump casing 24. A cylindrical pump discharge flow path 28 is formed between the pump 26 and the pump discharge flow path 26 . and the thrust bearing mechanism 1
The pump casing 24 is also extended to surround the external motor casing 30 of the canned motor unit 20, which is connected to the casing 26 that surrounds and fixes the pump casing 8, thereby extending the pump discharge passage 28.

The canned motor section 20 has a motor stator 34 hermetically housed between an external motor casing 30 and an internal motor casing 32 that are arranged concentrically, a motor rotor 36 having a sealed structure disposed within the internal motor casing 32, and a motor rotor 36 that has a closed structure.
One end of the motor rotor shaft 38 is extended to form a common shaft that serves as a support shaft for the impeller 14 disposed within the pump chamber 10. At both ends of the motor rotor 36, the motor rotor shaft 38 is pivotally supported by a lower bearing 40 and an upper bearing 42, and a lower (front) motor rotor chamber 44 and an upper (rear) motor rotor chamber 46 are provided at both ends of the motor rotor 36, respectively.
form. The upper end of the motor rotor shaft 38 is sealed with an end plate 48, and an upper fluid chamber 50 communicating with the upper motor rotor chamber 46 is provided.

On the other hand, the thrust bearing mechanism 18 includes thrust washers 54 that are in contact with the upper and lower surfaces of the thrust bearing 52 that is pivotally supported on the motor rotor shaft 38, respectively.
are fixedly arranged in the thrust bearing housing 56. In this case, the thrust bearing housing 56
The casing 26 that surrounds and fixes the pump discharge flow path 28 formed between the pump casing 24 and
The differential user part 58 is integrally formed in a part of the pump, and an opening part 60 is provided in a part of the downstream side thereof so as to be orthogonal to the pump discharge flow path 28, so that a part of the pump discharge fluid is transferred to the thrust bearing. It is configured to be introduced into the housing 56.

However, in the present invention, the thrust bearing mechanism 18 is configured to have an auxiliary pump function. For this purpose, for example, as shown in an enlarged view in FIG. 2, a liquid passage 62 parallel to the motor rotor shaft 38 is bored at the base of the thrust bearing 52, and an auxiliary liquid passage 62 communicating with the liquid passage 62 and extending in the radial direction is provided at the base of the thrust bearing 52. A pump discharge passage 64 is appropriately bored. In this case, the thrust bearing housing 56 surrounding the thrust bearing 52 is preferably configured to effectively guide the liquid discharged from the auxiliary pump discharge passage 64 to the adjacent canned motor section 20 side. Also,
Auxiliary pump discharge passage 64 of the thrust bearing 52
In order to smoothly introduce the liquid discharged from the lower motor rotor chamber 44 into the lower motor rotor chamber 44, a through hole 68 is appropriately provided in the bearing support 66 that supports the lower bearing 40.

Therefore, the pump handling fluid introduced into the thrust bearing housing 56 lubricates the thrust bearing mechanism 18 and pressurizes the handling fluid under the pumping action of the thrust bearing 52, lubricates the lower bearing 40, and flows through the through hole 68. and flows into the lower motor rotor chamber 44. In this way, the lower motor rotor chamber 4
The fluid introduced into the internal motor casing 3
2 and the motor rotor 36, the motor section is cooled during this time, and the upper motor rotor chamber 46
The liquid then flows directly into the upper fluid chamber 50 while lubricating the upper bearing 42 .

Further, in the present invention, the above-mentioned upper fluid chamber 5
A discharge pipe 70 configured to have the same outer diameter as the pump discharge channel 28 is connected to the upper part of the end plate 48 forming the pump discharge channel 28 to form a pump discharge channel 71.
On the other hand, an opening 72 is provided in the end plate 48,
A fixed aperture portion 74 is provided in this opening portion 72 . In this case, by configuring the throttle cross-sectional area of the fixed throttle part 74 to be adjustable as appropriate by replacing the fixed throttle part 74, etc., the flow rate of the handling liquid circulating within the canned motor unit 20 and therefore the degree of pressurization can be adjusted. becomes possible.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the submerged pump according to the present invention, the thrust bearing mechanism provided at the boundary between the pump section and the canned motor section has an auxiliary pump function.
The handling liquid to be circulated to the canned motor section can be easily introduced under pressure. In this case, there is an advantage that it can be easily manufactured without particularly providing an auxiliary pump chamber and without degrading the thrust bearing function in any way. In addition, since the handled liquid introduced into the canned motor section is discharged to a part of the pump discharge flow path in an adjustable flow rate, it is possible to effectively prevent gasification within the canned motor section and achieve smooth pump operation. can.

Although the preferred embodiments of the present invention have been described above, the pump of the present invention has a simple configuration and is easy to maintain, and can be immediately applied to existing canned motor pumps without major modification. Moreover, it has many excellent advantages such as being able to significantly improve pump function compared to conventional pumps.
The embodiment described above is a typical embodiment of the present invention, and it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a submerged pump according to the present invention, and FIG. 2 is an enlarged explanatory view of the main part of the thrust bearing having an auxiliary pump function shown in FIG. 10...Pump chamber, 12...Suction port, 14...
Impeller, 16... Inducer, 18... Thrust bearing mechanism, 20... Canned motor section, 22
...Discharge port, 24...Pump casing, 26...
...Casing, 28...Pump discharge channel, 30...
...External motor casing, 32...Internal motor casing, 34...Motor stator, 36...Motor rotor, 38...Motor rotor shaft, 40...
Lower bearing, 42... Upper bearing, 44... Lower (front) motor rotor chamber, 46... Upper (rear) motor rotor chamber, 48... End plate, 50...
upper fluid chamber, 52... thrust bearing, 54... thrust washer, 56... thrust bearing housing, 58... differential user section, 60... opening,
62...Liquid passage, 64...Auxiliary pump discharge passage,
66...bearing support body, 68...through hole, 70...discharge pipe, 71...pump discharge channel, 72...opening, 74...fixed constriction section.

Claims (1)

[Claims] 1. Consisting of a pump section and a canned motor section, a thrust bearing mechanism is provided at the boundary between the pump section and the canned motor section, and a part of the liquid handled by the pump is passed through the thrust bearing mechanism and the lower bearing. The submerged pump is introduced into the lower motor rotor chamber, then guided to the upper motor rotor chamber through the space between the internal motor casing and the motor rotor, and further led out to the pump discharge passage provided outside the canned motor section via the upper bearing. In the type pump, the thrust bearing mechanism includes a bearing housing that communicates with the pump discharge flow path and the lower motor rotor chamber, and a thrust bearing that rotates integrally with the motor rotor shaft is fixedly arranged inside the bearing housing. At the same time, a thrust washer is fixedly arranged opposite to this thrust bearing, and a liquid passage passing through the mounting base of the thrust bearing in the axial direction and an auxiliary pump discharge passage opening radially outward from the middle part of this liquid passage are provided. A diff user section is provided in a part of the pump discharge flow path, and a portion of the pump handling liquid is introduced into the bearing housing of the thrust bearing mechanism in a direction perpendicular to the discharge fluid on the downstream side of the diff user section. an opening is provided in a portion of the bearing housing, and a portion of the pump handling liquid introduced into the bearing housing is discharged from an auxiliary pump discharge passage provided in the thrust bearing and flows into the lower motor rotor chamber. Furthermore, an opening is provided on the upper motor rotor chamber side for allowing the pump handling liquid introduced into the motor rotor chamber to be led out to the pump discharge passage after a part of the liquid lubricates the bearing surface of the upper bearing. A submerged type pump characterized in that a fixed throttle part is provided in the opening part.