JPH08219075A - Canned motor pump - Google Patents

Abstract

PURPOSE: To provide a canned motor pump that can positively cool a motor and bearing and lubricate the bearings. CONSTITUTION: In a canned motor pump with bearings 53, 54 disposed on the impeller side and anti-impeller side of a rotor 23 having a through hole 21 in the axial direction, a pressure liquid chamber 12 for leading part of boosted liquid after passing an impeller is provided adjacently to the impeller side bearing 53, and it is so constituted that the liquid in the pressure liquid chamber 12 is separated in two directions so as to lead one liquid to the anti-impeller side bearing 54 via the impeller side bearing 53 and to return the other liquid to the back face of the impeller 22 through throttle mechanism 11.

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 capable of reliably cooling a motor and a bearing and lubricating the bearing.

[0002]

2. Description of the Related Art FIG. 3 is a view showing the structure of a conventional canned motor pump of this type. In FIG. 3, reference numeral 5 is a pump casing, and an impeller 22 is arranged in the pump casing 5. The opening of the pump casing 5 is covered with a casing cover 20. Further, reference numeral 10 is a hole for guiding a part of the pressurized liquid after passing through the impeller, which is formed in the casing cover 20. Reference numeral 59
Is a distance piece, and the distance piece 59 is fitted in the rotor 23 and is fixed together with the thrust plate 57, the shaft sleeve 55 and the impeller 22 by bolts at the rotor end. Rotor 24 and impeller bearing 5
Space 1 between the rotor 3 and the rotor 24 and the bearing 54 on the side opposite to the impeller
Between the end cover 17 and the bearing 54 on the side opposite to the impeller, and the bearing 53 on the side opposite to the impeller and the impeller 22.
Spaces 13 are respectively provided between and.

The bearing 53 on the impeller side and the sleeve 55 make the flow path a, the end face of the bearing 53 on the impeller side and the thrust plate 57 make the flow path c, and the can 60 of the stator and the can 61 of the rotor flow. Road D, the end surface of the bearing 54 on the side opposite to the impeller and the thrust plate 58
, And the bearing 54 on the side opposite to the impeller and the shaft sleeve 56 constitute a passage. A through hole 21 is formed in the rotor 23, and the through hole 21 is open on both sides including bolts at both ends. And the through hole 21
The space 3 communicates with the suction side of the pump.

In this type of canned motor pump, cooling of the motor and the bearing and lubrication of the bearing are performed as shown in FIG.
It has been performed by guiding a part of the pressurized liquid after passing through the impeller 22 to the space 1 through the hole 10 in the casing cover 20 and dividing the space 1 into two paths.
That is, the first path (hereinafter, referred to as path 1) passes from the space 1 through the flow path u, through the flow path i, into the space 13, through the balance hole 22a of the impeller 22, and returns to the suction side of the pump. . The second path (hereinafter referred to as path 2) passes from the space 1 through the flow path d, into the space 2, through the flow paths e and f, into the space 3, through the through hole 21, and the pump. Return to the suction side of. Cooling and lubrication of the impeller side bearing 53
The circulating fluid in the path 1 is used to cool the motor and the bearing 54 on the side opposite to the impeller, and the bearing 54 is lubricated by the circulating fluid in the path 2.

The amount of circulation in the paths 1 and 2 is greatly affected by the pressure of the space 1, the area of each flow channel iowa and the area of the through hole 21. Since both the path 1 and the path 2 are finally connected to the suction side of the pump, the pressure in the space 1 is
The suction pressure is added to the pressure loss of each of the flow channel Iouoka and the through hole 21. Here, the pressure in the space 13 of the path 1 is equal to the balance hole 22 a of the impeller 22.
Since the area is sufficiently large and there is almost no pressure loss, it can be regarded as almost suction pressure. Regarding the circulation amount, in route 1, space 1 and space 13
And the areas of the flow paths B and C, and in the path 2, the pressures of the space 1 and the spaces 2 and 3 and the suction pressure are similarly determined, and the area of each part.

In general, the bearing 53 on the impeller side has been devised such that there is no spiral groove on the inner peripheral surface and no axial groove on the inner peripheral surface. On the other hand, in the bearing 54 on the side opposite to the impeller, a spiral groove is provided on the inner peripheral surface, and
It has been devised that grooves are also provided in the axial direction on the inner peripheral surface. Grooves are provided in the radial direction on the sliding surfaces of the bearings 53 and 54 on the impeller side and the counter impeller side with the thrust plates 57 and 58. That is, the impeller-side bearing 53 has a shape in which the pressure loss with respect to the flow is larger than that of the counter impeller-side bearing 54. This means that the bearing 53 on the impeller side
By increasing the pressure loss of 1, the pressure in the space 1 is prevented from being reduced as much as possible, and the circulation amount is restricted so as not to flow to the route 1 excessively, while the necessary circulation amount is allowed to flow to the route 2. This is because

[0007]

However, in the above-described conventional canned motor pump, the shaft sleeves 55 and 56 and the thrust plate 5 that are on the rotating side during operation are in operation.
The bearings 53 and 54, which are generally made of carbon, mainly wear because the bearings 7 and 58 rotate while contacting the bearings 53 and 54 on the stationary side. The wear amount increases with the running time.

Even if the bearing 54 on the side opposite to the impeller is worn, a spiral groove is formed on the inner peripheral surface, and a groove is also formed in the axial direction on the inner peripheral surface. Is the thrust plate 5
Since a groove is provided on the sliding surface with 8 in the radial direction, the areas of the flow passages E and C are not so different from the area of the flow passage in the case of a bearing which is not worn. Therefore, there is not much difference in pressure loss for a constant flow rate. On the other hand, the bearing 53 on the impeller side has neither a spiral groove on the inner peripheral surface nor an axial groove. Therefore, as the wear increases, the area of the flow path a increases significantly, Therefore, the pressure loss for a constant flow rate is significantly reduced.

As described above, when the pressure loss in the bearing 53 on the impeller side becomes smaller, the pressure in the space 1 decreases, and the amount flowing in the path 1 becomes equal to the pressure in the space 1 as described above. Although it cannot be specified because it changes due to a change, the amount of the fluid flowing in the path 2 becomes smaller because the areas of the flow path E and the flow path D do not change much. For this reason, there is a drawback in that the circulation amount necessary for cooling the motor and cooling and lubricating the bearing 54 on the side opposite to the impeller cannot be secured, which causes overheating of the motor and the bearing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a canned motor pump capable of reliably cooling a motor and a bearing and lubricating the bearing.

[0011]

In order to solve the above problems, the present invention relates to a canned motor pump in which bearings are arranged on both the impeller side and the non-impeller side of a rotor having an axial through hole. Adjacent to the bearing on the side, a pressure liquid chamber for guiding a part of the pressurized liquid after passing through the impeller is provided, the liquid in the pressure liquid chamber is divided into two directions, and one of them is passed through the bearing on the side of the impeller. And is guided to the bearing of the non-impeller, and the other is returned to the back of the impeller via a diaphragm mechanism.

[0012]

According to the present invention, a part of the pressurized liquid discharged from the impeller is guided to the pressure liquid chamber, and the liquid in the pressure liquid chamber is divided into two directions, one of which is the bearing on the impeller side. It is possible to guide it to the bearing on the side opposite to the impeller via the, and to return the other to the back of the impeller via the diaphragm mechanism. Therefore, as will be described in detail later, even if the inner peripheral surface and the end surface of the bearing wear with the operating time, the circulation amount becomes almost constant due to the throttle mechanism in the first flow, and the bearing flow in the second flow. Since there are also spiral grooves provided on the inner peripheral surface, axial grooves, and radial grooves provided on the sliding surface of the thrust plate, the circulation amount increases slightly.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a canned motor pump according to the present invention. Portions denoted by the same reference numerals as those in FIG. 3 indicate the same or corresponding portions.

The impeller side bearing 53 and the casing cover 2
0 and the distance piece 59 and the shaft sleeve 55 form a space 12 that constitutes a pressure liquid chamber, and the inner peripheral surface of the casing cover 20 and the outer peripheral surface of the distance piece 59 constitute a non-contact throttle mechanism 11. . Aperture mechanism 1
The flow path A is constituted by 1. Both the inner peripheral surface of the casing cover 20 and the outer peripheral surface of the distance piece 59, or either one surface is plated or sprayed. The bearings 53, 54 on the impeller side and the non-impeller side are
In both cases, a spiral groove is provided on the inner peripheral surface, and a groove is also provided on the inner peripheral surface in the axial direction.
Grooves are provided in the radial direction on the sliding surface of and. Other configurations are similar to those of the canned motor shown in FIG.

In the canned motor pump having the above structure, the pressurized liquid introduced from the hole 10 after passing through the impeller enters the space 12 constituting the pressure liquid chamber, and flows from there in two directions. The first flow is a flow that passes through the throttle mechanism 11, passes through the balance hole 22a of the impeller 22, and returns to the suction side of the pump (hereinafter referred to as flow 1). The second flow is from the space 12 to the flow path B, the flow path C, the space 1,
Channel D, space 2, channel E, channel C, space 3, through hole 21
Is a flow that returns to the suction side of the pump (hereinafter referred to as flow 2). Since both stream 1 and stream 2 are finally connected to the suction side of the pump, the pressurized liquid after passing through the impeller flows from the space 12 to the suction side, which is a lower pressure portion. Stream 2 cools the motor and bearings 53 and 54 and lubricates the bearings 53 and 54.

The circulation amounts of stream 1 and stream 2 are
Is greatly affected by the pressure of each channel, the area of each flow channel, and the area of the through hole 21. Since both the stream 1 and the stream 2 are finally connected to the suction side of the pump, the pressure in the space 12 has a magnitude obtained by adding the suction pressure to the pressure loss of each of the flow channel eye wafer and the through hole 21. here,
The pressure of the space 13 of the flow 1 can be regarded as almost suction pressure because there is almost no pressure loss because the area of the balance hole 22a of the impeller 22 is made sufficiently large. The circulation amount of the flow 1 is mainly determined by the area of the flow passage A, and the circulation amount of the flow 2 is determined by the areas of the flow passage A, the flow passage C, the flow passage D, the flow passage E, the flow passage F, and the through hole 21. Decided. For flow path a, flow path c, flow path e, and flow path f, in addition to the spiral groove and axial groove on the inner peripheral surface of the corresponding bearing, the radial direction of the sliding surface with the thrust plate The area of the groove is also included.

The dimensions of the respective parts constituting these flow paths are determined so that the circulation amount necessary for surely cooling and lubricating the motor and the bearing can be obtained. Here, a situation during actual operation of the canned motor pump will be described. Regarding wear, the can 60 of the surface of the throttle mechanism 11 forming the flow path A and the stator forming the flow path D
Since the rotor can 61 and the rotor can 61 are not in contact with each other, they are extremely small except for wear due to the flow rate of the circulating fluid. On the other hand, the surfaces that make up the flow path a, flow path c, flow path o, and flow path f are in contact with each other and rotate relatively, so wear on the inner peripheral surface of the bearing gradually increases. To go. However, the bearing 5 on the impeller side
3 and the bearing 54 on the side opposite to the impeller, the inner peripheral surface is provided with a spiral groove, and the inner peripheral surface is also provided with a groove in the axial direction. Since the groove is provided in the moving surface in the radial direction, even if the inner peripheral surface or the end surface of the bearing is worn, these grooves are not worn. Therefore, the flow channel Ioka which affects the magnitude of the pressure in the space 12 Each area hardly increases. That is, the pressure in the space 12 hardly decreases even when the inner peripheral surface and the end surface of the bearing are worn.

Therefore, in addition to the operating time, the circulation amount of the stream 1 hardly changes, and the circulation amount of the stream 2 slightly increases. Therefore, the cooling of the motor and the cooling and lubrication of the bearing can be performed more reliably with the operation time.

FIG. 2 is a sectional view showing a structure in which a replaceable bush B is attached to the casing cover of the canned motor pump of the present invention. The bush B has an economical effect so that the casing cover does not need to be replaced when the peripheral surface of the throttle mechanism is worn out. Also, plating or thermal spraying on both or one of the peripheral surfaces that make up the diaphragm mechanism is
This is because it has an excellent effect of protecting the peripheral surface of the diaphragm mechanism from wear. In the embodiment shown in FIGS. 1 and 2, the throttle mechanism is formed by the gap formed by the inner peripheral surface of the casing cover and the outer peripheral surface of the distance piece. However, it is a mechanism that returns the liquid in the pressure liquid chamber to the rear surface of the impeller while squeezing the liquid. Other mechanisms may be used as long as they are available.

[0020]

As described above, according to the present invention, the following excellent effects can be obtained. (1) A pressure liquid chamber for guiding a part of the pressurized liquid after passing through the impeller is provided adjacent to the bearing on the impeller side, and the liquid in the pressure liquid chamber is divided into two directions, one of which is the impeller. By guiding the other side of the bearing to the bearing of the impeller and returning the other side to the rear side of the impeller via the throttle mechanism, even if the inner peripheral surface of the bearing wears over time, The amount of circulation for cooling the bearing and lubricating the bearing is determined by the radius of the throttle mechanism and the spiral groove on the inner peripheral surface of the bearing and the axial groove on the inner peripheral surface and the sliding surface of the thrust plate. Since there is a groove in the direction, the circulation amount increases slightly, so that cooling of the motor and the bearing and lubrication of the bearing can be reliably performed. (2) Since the throttle mechanism can be configured by the gap formed by the inner peripheral surface of the casing cover and the outer peripheral surface of the distance piece provided between the shaft sleeve and the impeller, no separate parts are required. A simple diaphragm mechanism can be provided. (3) Since the replaceable bush is attached to the casing cover, there is an economic effect that the casing cover does not need to be replaced when the peripheral surface of the diaphragm mechanism is worn. (4) By plating or spraying both or one of the peripheral surfaces of the throttle mechanism, it is possible to effectively protect the peripheral surface of the throttle mechanism from wear.

[Brief description of drawings]

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

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

FIG. 3 is a cross-sectional view showing a conventional canned motor pump of this type.

[Explanation of symbols]

 1, 2 and 3 space 10 hole 11 throttle mechanism 12 and 13 space 17 end cover 20 casing cover 21 through hole 22 impeller 23 rotor 24 rotor 25 stator 53, 54 bearing 55, 56 shaft sleeve 57, 58 thrust plate 59 Distance piece a, a, u, d, o, flow path

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shigeru Mishima 4-1-1 Motofujisawa, Fujisawa-shi, Kanagawa Ebara Densan Co., Ltd. (72) Inventor Toshiya Akasaka 4-1-1, Fujisawa, Kanagawa Company Ebara Densan (72) Inventor Keiichi Wakabayashi 4-1-1 Motofujisawa, Fujisawa-shi, Kanagawa Ebara Densan Company (72) Inventor Atsushi Oyama 4-1-1 Motofujisawa, Fujisawa, Kanagawa Ebara Corporation Inside

Claims (6)

[Claims] 1. A canned motor pump in which bearings are arranged on both sides of an impeller side and an opposite impeller side of a rotor having a through hole in an axial direction, and the pressure is increased after passing through the impeller adjacent to the impeller side bearing. A pressure liquid chamber for guiding a part of the liquid is provided, the liquid in the pressure liquid chamber is divided into two directions, one of which is guided to the bearing of the non-impeller via the bearing of the impeller side, and the other of which is a throttling mechanism. A canned motor pump characterized in that the canned motor pump is configured to be returned to the rear surface of the impeller via the. 2. The pressure liquid chamber comprises a space defined by a bearing on the impeller side, a shaft sleeve, a distance piece provided between the shaft sleeve and the impeller, and a casing cover. The canned motor pump according to claim 1, which is characterized in that. 3. The throttle mechanism comprises a gap formed by an inner peripheral surface of a casing cover and an outer peripheral surface of a distance piece provided between a shaft sleeve and an impeller. Canned motor. 4. The canned motor pump according to claim 3, wherein both surfaces of the inner peripheral surface of the casing cover and the outer peripheral surface of the distance piece, or either one surface is plated or sprayed. 5. The canned motor pump according to claim 3, wherein a replaceable bush is attached to an inner peripheral surface of the casing cover to configure the throttle mechanism. 6. The canned motor pump according to claim 5, wherein both the inner peripheral surface of the bush and the outer peripheral surface of the distance piece, or one of the surfaces is plated or sprayed.