JPH07119678A - Canned motor pump device - Google Patents

Abstract

PURPOSE:To improve pump efficiency by enhancing a cooling effect for a motor of a canned motor pump. CONSTITUTION:In a canned motor pump device where a back cover 13 where a shaft 3 to which an impeller 6 is connected is projected and pierced is installed on the lower side of a pump casing 12 having a suction port opened on the upper surface thereof, and a canned motor supported by journal bearings 7a, 7b of two, upper and lower parts is stored, a passage 18b for cooling a motor, which has the flow direction in the peripheral direction is provided on the outer peripheral surface of a motor casing 14a of the motor.

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, and more particularly to a canned motor pump that requires cooling of the stator side of the canned motor.

[0002]

2. Description of the Related Art As a conventional method of cooling a motor of a pump of this type, for example, the technique disclosed in Japanese Utility Model Application No. 51-32984 is known. This specification uses a part of the liquid handled by the pump taken out from the discharge side of the pump, and the flow direction of the fluid flowing to the outside of the motor stator can only flow in the axial direction due to the structure. On the other hand, the present invention aims to flow the fluid outside the motor stator in the circumferential direction, and the structure is also different from the known example. Further, Japanese Patent Application No. 5-31568 describes a method of flowing a cooling fluid of a motor using an auxiliary impeller for realizing the present invention.

[0003]

In the above-mentioned prior art, in the case of the former known example, the fluid flowing to the outside of the motor stator for cooling the motor can flow only in the axial direction because of its structure. Moreover, it cannot be applied to high temperature water because it uses a part of the handling liquid discharged from the pump. The latter known example is effective for overcoming this problem, but if the flow rate of the auxiliary impeller is increased in order to enhance the cooling effect, the efficiency of the pump decreases.

An object of the present invention is to provide a canned motor type pump device capable of sufficiently cooling even if the flow rate of the auxiliary impeller is suppressed to some extent and enhancing pump efficiency.

[0005]

In order to achieve the above object, the structure of the first invention of the canned motor type pump device of the present invention is such that an impeller is provided below a pump casing having a suction port opened on the upper surface. A canned motor supported by two upper and lower journal bearings with a back cover penetrating the connected shaft projecting through it, and an auxiliary impeller connected to the shaft are provided on the discharge side of the auxiliary impeller. In a canned motor type pump device in which water channels are arranged in parallel inside and outside the motor stator, the casing outside the motor stator is a double cylinder so that the fluid flowing in the water channel outside the motor stator flows in the circumferential direction. A rectifying plate having a structure is disposed between the outer cylinder and the inner cylinder, thereby forming one or a plurality of spiral flow paths. Also, a flow path such as a hole for connecting one end to the inner side of the inner cylinder, and a flow path for the other end connecting to the outer side of the outer cylinder are arranged.

Further, in the structure of the second invention of the canned motor type pump device of the present invention, the casing outside the motor stator of the first invention has a double cylindrical structure, and the outer cylinder and the inner cylinder are In between, a disk-shaped partition plate is placed so as to divide the space into multiple parts in the axial direction, and in order to connect each of the separated chambers, a partition plate other than both end faces of the double cylinder is arranged on the circumference. Make holes in one or more places, and arrange the adjacent partition plates so that the positions of the holes are staggered. And a flow path such as a hole for connecting one of the outermost chambers of the partitioned chamber to the inner side of the inner cylinder, and a hole for connecting the other endmost chamber to the outer side of the outer cylinder. It has a flow path such as.

Further, the structure of the third invention of the canned motor type pump device of the present invention is a double cylinder structure in which the outer casing of the motor stator of the first invention has no gap between the outer cylinder and the inner cylinder. A spiral groove is formed on the inner diameter side of the outer cylinder or the outer diameter side of the inner cylinder by cutting or molding, and one end of the groove connects to the inner side of the inner cylinder and a flow path such as a hole. , And the flow path such as a hole whose one end communicates with the outside of the outer cylinder.

Further, the structure of the fourth invention of the canned motor type pump device of the present invention is a double cylinder structure in which the outer casing of the motor stator of the first invention has no gap between the outer cylinder and the inner cylinder. Has a plurality of grooves in the circumferential direction by cutting or molding on the inner diameter side of the outer cylinder or the outer diameter side of the inner cylinder, and one or more axial direction for connecting the respective circumferential grooves. Make a groove. At that time, the positions of the axial grooves adjacent to each other in the axial direction are arranged so as to be staggered. Then, a flow path such as a hole for connecting one of the chambers at the outermost of the arranged circumferential grooves to the inner side of the inner cylinder, and the other chamber at the outermost end is further connected to the chamber of the outer cylinder. A flow path such as a hole that connects to the outside.

[0009]

The function of the most basic construction of the above technical means will be described below.

The inner cylinder of the motor casing of double cylinder structure holds the motor stator and at the same time constitutes a flow path for flowing the cooling liquid to the outside of the motor stator. The outer cylinder is paired with the inner cylinder to form a flow path for flowing the cooling liquid outside the motor stator. The flow straightening plate is located between the inner cylinder and the outer cylinder to form a flow passage.The flow straightening plate makes the flow direction of the cooling liquid circumferential, and at the same time reduces the flow passage area to increase the flow velocity of the cooling liquid. The motor casing can be cooled efficiently and uniformly.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a vertical sectional view showing an embodiment of the present invention. In FIG. 1, reference numeral 12 denotes a pump casing having a suction port opened on the front surface, which is fixed to the foundation. A rear cover 13 is attached to the lower side of the pump casing 12, and a shaft 3 to which an impeller 6 is connected is projectingly penetrated through the rear force bar 13. The impeller 6 is provided with a hollow shaft 4 on the outer circumference of the shaft 3 attached to the shaft 3 by an impeller nut 16.
The shaft 3 and the hollow shaft 4 are fixed by a connecting rod 5.
The hollow shaft 4 has journal bearings 7a and 7b arranged above and below to support it. A motor stator 1 and a motor rotor 2 that transmit power to the impeller 6 are installed on the hollow shaft 4. In order to insulate the motor stator 1 and the motor rotor 2 from the pumping liquid, the motor stator can 10 and the motor rotor can 11
Is provided. In order to receive the weight of the rotor parts and the unbalanced axial thrust when the pump is stopped, the thrust disk 9 is connected to the lowermost end of the connecting rod 5 and the upper thrust bearing 8a and the lower thrust bearing are provided with a plurality of moving pads. It is supported by the bearing 8b. The inner motor casing 14a holds the entire motor portion such as the motor stator 1 and the bearing portions 7a, 7b, 8a, 8b, and is indirectly fixed to the foundation by being connected to the back cover 13. Inner motor casing 14a
A current plate 15a, upper and lower covers 20a, 20
b and the outer motor casing 14b are arranged. The cooling liquid inflow chamber 18a surrounded by the inner motor casing 14a, the lower cover 20a, the outer motor casing 14b, and the rectifying plate 15a passes through the flow passage 19a to pass through the auxiliary impeller 9.
Is connected to the pressure increasing chamber 21 on the discharge side. The cooling liquid inlet chamber 18a passes through the cooling flow passage 18b and the cooling liquid outlet chamber 18a.
upper journal bearing 7 which is connected to c and through flow path 19c
It is connected to the upper part of a and is also connected to the heat exchanger 17 through the flow path 19b.

During operation of the pump, the auxiliary impeller 9 rotates, whereby the pressure of the cooling liquid is increased and a part thereof flows through the flow passage 19a into the cooling liquid inlet chamber 18a. Further, the cooling liquid flows into the cooling liquid outlet chamber 18c through the cooling flow passage 18b, but the heat generated from the motor stator 1 when passing through the cooling flow passage 18b is absorbed through the inner motor casing 14a to cool the motor stator 1. To do. The other part of the coolant that is boosted by the auxiliary impeller 9 passes through the upper thrust bearing 8a, the lower journal bearing 7b, the gap between the motor stator can 10 and the motor rotor can 11, the upper journal bearing 7a, and the flow path 19c. Flow into the cooling liquid outlet chamber 18c, and together with the cooling liquid flowing through the cooling flow passage 18b, flow into the heat exchanger 17 via the flow passage 19b. The coolant whose temperature has risen after passing through the motor is cooled by the heat exchanger 17, and then flows into the suction chamber 22 of the auxiliary impeller together with makeup water supplied from a small amount from the outside.

FIG. 2 shows an arrangement example of the current plate 15a of the embodiment. The cooling flow path 18b has a spiral shape and flows between the inner motor casing 14a and the outer motor casing 14b in the circumferential direction.

FIG. 3 shows another embodiment of a disk-shaped straightening plate 15b.
Are arranged in a plurality of axial directions, and the holes 23a formed in the straightening plate 15b are arranged alternately so that the motor casing 14
A cooling passage 18d is formed in the circumferential direction with respect to a and 14b.

FIG. 4 shows another embodiment of the cooling passage 1 in which a spiral groove is provided on the outer peripheral surface of the inner motor casing 14a and an outer motor casing 14b is fitted into the inner motor casing 14a without a gap.
8e, which has the same function as in FIG.

FIG. 5 shows another embodiment in which a plurality of circumferential grooves are provided on the outer peripheral surface of the inner motor casing 14a, and axial grooves are arranged so as to communicate with each other. An outer motor casing 14b that fits without a gap therein is fitted to form cooling flow paths 18f and 23b, which have the same function as in FIG.

[0018]

According to the present invention, it is possible to supply a canned motor type pump device which can efficiently and uniformly cool the canned motor, has high pump efficiency, and has high motor reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a canned motor type pump according to the present invention.

FIG. 2 is a vertical sectional view of an embodiment of a motor cover of a canned motor according to the present invention.

FIG. 3 is a vertical sectional view of a second embodiment of the motor cover of the canned motor according to the present invention.

FIG. 4 is a vertical sectional view of a third embodiment of the motor cover of the canned motor according to the present invention.

FIG. 5 is a vertical sectional view of a fourth embodiment of the motor cover of the canned motor according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor stator, 2 ... Motor rotor, 3 ... Shaft, 4 ... Hollow shaft, 5 ... Connecting rod, 6 ... Impeller, 7a ... Upper journal bearing, 7b ... Lower journal bearing, 8a ... Upper thrust bearing,
8b ... Lower thrust bearing, 9 ... Auxiliary impeller and thrust disk, 10 ... Motor stator can, 11 ... Motor rotor can, 12 ... Pump casing, 13 ... Rear cover,
Reference numeral 14a ... Inner motor casing, 14b ... Outer motor casing, 15a ... Helical straightening plate, 15b ... Disc-shaped straightening plate, 16 ... Impeller nut, 17 ... Heat exchanger, 18a-1.
8f ... Cooling channel, 19a-19c ... Channel, 20a ... Lower cover, 20b ... Upper cover.

Claims (1)

[Claims] 1. A canned motor in which a rear cover, which projects and penetrates a shaft to which an impeller is connected, is attached to a lower side of a pump casing having a suction port opened on an upper surface, and which is supported by journal bearings at upper and lower positions, and the shaft. In a canned motor type pump device, which has an auxiliary impeller connected to the auxiliary impeller, and the water passage on the discharge side of the auxiliary impeller is arranged in parallel inside and outside the motor stator, the casing of the canned motor is doubled. A canned motor type pump device having a cylindrical structure and having a structure in which an annular gap fluid flows in a circumferential direction.