JP3363085B2 - Canned motor pump - Google Patents

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 cooling of a motor portion, cooling and lubrication of a bearing reliably, and reduction of an axial thrust force acting on an impeller. The present invention relates to a canned motor pump having improved pump suction performance.

[0002]

2. Description of the Related Art FIG. 6 is a diagram showing a general structure of a conventional canned motor pump of this type. As shown in the figure, an impeller 2 is arranged inside the pump casing 1 of the pump portion, and a casing cover 3 is fixed to an opening portion of the pump casing 1 on the high pressure side. Further, the casing cover 3 is formed with a circulation groove 4 for guiding a part of the pressurized pump handling liquid after passing through the impeller 2 to the space A described below.

One end side of the rotor 5 is inserted into the inside of the casing cover 3, and the distance piece (sleeve) 6, the thrust plate 7a, the shaft sleeve 8a and the above-mentioned fitted to the one end side of the rotor 5. The impeller 2 is fixed via bolts, and the thrust plate 7b and the shaft sleeve 8b are fixed on the other end side of the rotor 5 via bolts.

The rotor 5 has a pair of bearings 9 at both ends thereof.
While being rotatably supported via a and 9b,
The rotor 10 of the motor unit is fixed to the substantially center thereof, and the space A is provided between the rotor 10 and the bearing 9a on the impeller side.
However, there is a space B between the rotor 10 and the bearing 9b on the side opposite to the impeller, and the space 9 between the rotor 10 and the bearing 9b on the side opposite to the end cover 11 and the impeller.
A space C is provided between the bearing 9a and the impeller 2 on the impeller side.
A space D is provided between each of them.

A flow path a is provided between the impeller-side bearing 9a and the shaft sleeve 8a, and a flow path b is provided between the end face of the impeller-side bearing 9a and the thrust plate 7a. 1
2a and the can 12b of the stator 13, a flow path c is provided, and a flow path d is provided between the end surface of the bearing 9b on the opposite side of the impeller and the thrust plate 7b. Sleeve 8
The flow path e is formed between each of them and b.

A through hole 14 penetrating in the axial direction is formed inside the rotor 5, and the through hole 14 is open on both sides including bolts at both ends. The through hole 14 allows the space C between the end cover 11 and the bearing 9b on the opposite side of the impeller and the suction side of the pump to communicate with each other.

In this type of canned motor pump, cooling of the motor part and cooling and lubrication of the bearings 9a and 9b are
A part of the pressurized pump handling liquid after passing through the impeller 2 is passed through the circulation hole 4 provided in the casing cover 3 to the rotor 10.
It is carried out by introducing it into the space A between the bearing 9a and the bearing 9a on the impeller side and dividing the space A into two paths.

That is, the first path is a path from the space A through the flow path b and the flow path a into the space D, after passing through the balance hole 2a of the impeller 2 and then returning to the suction side of the pump. Is. The second path enters the space B from the space A through the flow path c, enters the space C through the flow path d and the flow path e, and then through the through hole 14 to the suction side of the pump. It is a route to return. And cooling and lubrication of the bearing 9a on the impeller side,
The lubricating liquid (pump handling liquid) passing through the first path is used, and the cooling of the motor part and the cooling and lubrication of the bearing 9b on the side opposite to the impeller are performed by the lubricating liquid passing through the second path. .

Here, the amount of the pump handling liquid that circulates through the first passage and the second passage is greatly influenced by the pressure in the space A, the areas of the flow paths a to e, and the area of the through hole 14. It That is, since the first path and the second path each lead to the suction side of the pump at the end, the pressure in the space A is
The size is the sum of the pressure loss of each of the flow paths a to e and the through hole 14 and the suction pressure.

Here, since the pressure in the space D in the first path can be made to have almost no pressure loss by making the area of the balance hole 2a of the impeller 2 sufficiently large, the suction pressure is reduced. Can be about the same value as. In addition, the amount of the pump handling liquid that circulates is determined by the differential pressure between the space A and the space D and the area of the flow paths a and b in the first path, and in the second path, similarly, It is determined by the respective differential pressures of A, the spaces B and C, and the suction pressure, and the area of each part.

Generally, the inner peripheral surface of the cylindrical portion of the bearing 9a on the impeller side is formed as a flat surface, and the bearing 9 on the side opposite to the impeller side is formed.
A spiral groove and a groove extending in the axial direction are formed on the inner peripheral surface of the cylindrical portion b. Further, the thrust plates 7a, 7b of the bearings 9a, 9b on both the impeller side and the side opposite to the impeller side, respectively.
Grooves extending in the radial direction are provided on the sliding surfaces of and. As a result, the impeller-side bearing 9a is configured to have a larger pressure loss with respect to the flow than the impeller-side bearing 9b.

With this structure, the pressure loss of the bearing 9a on the impeller side is increased to prevent the pressure in the space A from decreasing as much as possible, while an excessive amount of the pump handling liquid in the first path. Can be restricted from flowing, and a required amount of pumping liquid can flow through the second path.

[0013]

However, in the above conventional canned motor pump, the shaft sleeves 8a, 8b on the rotating side and the thrust plates 7a, 7b are
Since the bearings 9a and 9b on the fixed side rotate while coming into contact with the bearings 9a and 9b made of carbon, the bearings 9a and 9b, which are generally made of carbon, mainly wear, and the amount of wear increases with the lapse of operating time.

Even if the bearing 9b on the side opposite to the impeller wears, the inner peripheral surface is provided with the spiral groove and the axially extending groove as described above, and the thrust plate 7b is further provided. Since the sliding surface of and is also provided with a groove extending in the radial direction, the areas of the flow paths d and e are not so different from the area of the flow path 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 9a on the impeller side has a flat inner peripheral surface and is not provided with a spiral groove or a groove extending in the axial direction.
As the wear increases, the area of the flow path a formed between the shaft sleeve 8a and the shaft sleeve 8a significantly increases, and therefore the pressure loss for a constant flow rate decreases significantly.

As described above, when the pressure loss of the bearing 9a on the impeller side is reduced, the pressure in the space A is reduced as described above, and the areas of the flow passages d and e are considerably reduced. Since it does not change, there is less pumping liquid flowing in the second path. For this reason, there is a problem in that the required amount of pump handling liquid cannot be secured for cooling the motor part and for cooling and lubricating the bearing 9b on the side opposite to the impeller, causing heating of the motor part and the bearing.

Here, the amount of the pump handling liquid flowing through the first path changes depending on the change in the pressure in the space A and cannot be specified. The experimental results are shown in FIG. 7. In the figure, the horizontal axis represents the pump discharge amount of the tested pump, and the vertical axis represents the total head, efficiency and pressure in the space D of the tested pump. The suction pressure and the discharge pressure of the pump are not shown in the figure because they are not necessary for specifying the amount of pump handling liquid flowing through the first path. Curves C1, C2, and C3 show changes in the pressure in the space D with respect to changes in the pump discharge amount.

In the figure, in the curve C1, there is no wear on the bearing 9a on the impeller side, so that the flow path a
If the gap is normal, the bearing 9a
When the flow channel a is worn and a gap about 2.5 times the regular gap is formed in the flow channel a, the curve C3 also has a gap about 4.1 times the regular gap in the flow channel a. It shows the case where occurs respectively.

In any case, as the pump discharge amount increases, the pressure in the space D decreases and the pressure in the space D increases as the gap between the flow paths a increases. That is, as the wear of the bearing 9a on the impeller side increases, the size of the balance hole 2a and the suction pressure do not change, but the pressure in the space D increases, so the differential pressure across the balance hole 2a increases. ,
The amount of pump handling liquid passing through the balance hole 2a increases. That is, it can be seen that the amount of the pump handling liquid flowing through the first path gradually increases as the wear of the bearing 9a on the impeller side increases.

When the pressure in the space D increases, the so-called axial thrust force acting on the impeller 2 in the axial direction increases by the increased pressure, and the sliding surface of the bearing 9a with the thrust plate 7a increases. Not only does the load acting on the bearing increase, which shortens the life of the bearing 9a, but also the flow velocity of the pump handling liquid passing through the balance hole 2a increases, and the pump handling liquid enters the impeller 2 from the suction side. This will prevent it from flowing in, which will adversely affect the suction performance of the pump.

The present invention has been made in view of the above circumstances, and can surely cool the motor portion and the bearings, and reduce the axial thrust force acting on the impeller. Another object of the present invention is to provide a canned motor pump capable of improving the suction performance of the pump.

[0021]

A canned motor pump according to the present invention comprises a can rotor and a rotor to which a can rotor and a pump impeller are fixed. The bearings are arranged at both ends of the rotor and the impeller passes through. In a canned motor pump configured to perform cooling of the motor rotor and a can-sealed motor stator arranged through a gap in the pump handling liquid afterwards, and cooling and lubrication of each bearing, As each of the bearings, a groove through which the pump handling liquid flows is provided on the inner peripheral surface, and a balance hole is provided on the outer diameter side of the liner diameter of one of the main plate and the side plate of the impeller, the impeller side bearing. A pressure liquid chamber for guiding a part of the pump handling liquid to the inside is provided at a position adjacent to the end face on the impeller side, and the pump handling liquid in the pressure liquid chamber is divided into two directions. Square cooling of the motor section with a pump handling liquid, and subjected to cooling and lubrication of both bearings, characterized by being configured to return to the pump suction side via the diaphragm mechanism and the other pump the pumped fluid.

Thus, it is possible to prevent the outflow amount of the high-pressure pump handling liquid introduced into the pressure liquid chamber from increasing and the pressure in the pressure liquid chamber from decreasing with the passage of time. Therefore, it is possible to prevent the amount of lubricating liquid (pump handling liquid) flowing through the motor unit and both bearings from decreasing. At the same time, a balance hole provided on the outer diameter side of the liner diameter of one of the main plate and the side plate of the impeller reduces the axial thrust force that acts on one of the main plate and the side plate of the impeller to reduce the total axial thrust force. Can be reduced.

Further, the throttle mechanism is provided between the casing cover and the sleeve that rotates integrally with the rotor, and between the casing cover and the outer peripheral surface of the boss portion of the impeller. As a result, it is possible to prevent the pressure in the pressure fluid chamber from decreasing via the double throttle mechanism.

Further, a third throttle mechanism is provided between the inner peripheral surface of the liner on the main plate side of the impeller and the pump casing. As a result, the amount of the pump handling liquid flowing between the inner peripheral surface of the liner on the main plate side and the pump casing can be reduced, and the pump efficiency can be improved.

Further, a through hole is provided inside the rotor for returning the pump handling liquid after cooling the motor part and cooling and lubricating both bearings to the pump suction side. As a result, the entire amount of the high-pressure pump handling liquid introduced into the pressure fluid chamber can be returned to the suction side of the pump.

Further, the pump handling liquid after cooling the motor part and cooling and lubricating both bearings flows to the outside of the pump casing into the pump casing which houses the rotor and the stator of the motor part. It is characterized in that a through hole is provided. As a result, it is possible to prevent the pumped liquid that has become hot due to cooling of the motor part and cooling and lubrication of both bearings from returning to the vicinity of the inlet of the impeller.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described based on FIGS. FIG. 1 is a sectional view showing a structure of a canned motor pump according to a first embodiment of the present invention. The basic structure of the canned motor pump itself is substantially the same as that of the conventional example shown in FIG. 6, and the same or corresponding parts will be denoted by the same reference numerals and redundant description thereof will be omitted.

As shown in the figure, by providing an inwardly projecting convex portion 3a on the inner peripheral surface of the casing cover 3, the impeller side bearing 9a, the casing cover 3, the distance piece (sleeve) 6 and A space E as a pressure liquid chamber is formed between the shaft sleeve 8a and the shaft sleeve 8a. A non-contact first diaphragm mechanism 20a is formed between the inner peripheral surface of the convex portion 3a and the distance piece 6. That is, the inner peripheral surface of the convex portion 3a approaches the outer peripheral surface of the distance piece 6 with a slight gap,
The flow path f is formed here.

Inside the casing cover 3, there is provided a through hole 21 for introducing a part of the pump handling liquid whose pressure is increased by the impeller 2 into the space (pressure liquid chamber) E. Further, by forming a sleeve-like protruding portion 3b on the impeller-side end surface of the casing cover 3, the inner peripheral surface of the protruding portion 3b and the boss portion 2b of the impeller 2 are formed.
A non-contacting second diaphragm mechanism 20b is formed between and. That is, the inner peripheral surface of the protruding portion 3b approaches the outer peripheral surface of the boss portion 2b of the impeller 2 with a slight gap, and the flow path g is formed therein. At the same time, the protrusion 3b forms two spaces F and G between the casing cover 3 and the impeller 2 with the second diaphragm mechanism 20b interposed therebetween, and the space G is a balance hole of the impeller 2. It is adapted to communicate with the suction side of the pump via 2a.

Further, by providing the second balance hole 2d on the outer diameter side of the liner diameter of the main plate 2e of the impeller 2, the space H defined by the casing 1, the impeller 2 and the casing 3 and the blades are formed. The blades of the impeller partitioned by the main plate 2e and the side plate 2f of the wheel 2 communicate with each other.

Here, the bearing 9b on the side opposite to the impeller is provided.
In the same manner as in the conventional example, a spiral groove and a groove extending along the axial direction are formed on the inner peripheral surface,
Similarly, the bearing 9a on the impeller side is also formed with a spiral groove and a groove extending along the axial direction on the inner peripheral surface thereof. Also,
As in the case of the conventional example, a groove extending in the radial direction is provided on the sliding surface of each bearing 9a, 9b with each thrust plate 7a, 7b.

In the canned motor pump having the above structure, the pumped liquid whose pressure has been increased after passing through the impeller is guided from the circulation hole 21 provided in the casing cover 3 into the space E which constitutes the pressure liquid chamber, and from there, 2 Flow in one direction.

The first flow is a flow that passes through the first throttle mechanism 20a and the second throttle mechanism 20b, passes through the balance hole 2a of the impeller 2, and returns to the suction side of the pump.
The second flow is from the space E to the flow path a, the flow path b, the space A,
Channel c, space B, channel d, channel e, space C and through hole 1
It is a flow that passes through 4 in order and returns to the suction side of the pump.
Since both the first flow and the second flow are connected to the suction side of the pump at the end, the pumped liquid whose pressure is increased after passing through the impeller is discharged from the space E to the suction side of the pump, which is a lower pressure part. And the second flow cools the motor part and cools and lubricates the bearings 9a and 9b.

Here, the circulation amount of the pump handling liquid flowing along the first flow and the second flow has a great influence on the pressure in the space E, the areas of the flow paths a to g, and the area of the through hole 14. To be done. Since both the first flow and the second flow are finally connected to the suction side of the pump, the pressure in the space E is
To g and the pressure loss of each of the through holes 14, the suction pressure is added.

Here, the pressure in the space G located in the first flow is made substantially large by making the area of the balance hole 2a of the impeller 2 large enough to eliminate the pressure loss.
It can be regarded as almost suction pressure. The circulation amount of the pump handling liquid of the first flow is mainly determined by the areas of the flow paths f and g, and the circulation amount of the pump handling liquid of the second flow is of the flow paths a to e and the through hole 14. It depends on the area. Here, regarding the flow paths a to e, in addition to the spiral groove and the groove extending in the axial direction provided on the inner peripheral surfaces of the bearings 9a and 9b,
It also includes the area of radial grooves provided on the sliding surfaces of the thrust plates 7a and 7b. The dimensions of each part for forming these flow paths are as follows: the cooling of the motor part, the bearing 9a,
It is determined so that the circulating amount of the pump handling liquid necessary for surely cooling and lubricating 9b can be obtained.

FIG. 2 shows a pressure distribution in the axial direction which acts on each surface of the main plate 2e and the side plate 2f of the impeller 2. In the figure, pressures p ₁ , p ₂ , p ₃ and p ₄ respectively indicate pressure in the axial direction, the length of the line segment indicates the magnitude of pressure, and the arrow indicates the direction of pressure.

As shown in the figure, the pressure acting on each surface of the main plate 2e and the side plate 2f gradually decreases from the outer diameter of the impeller 2 toward the liner portion. Impeller 2
It can be considered that the pressure p ₁ on the side of the main plate 2e and the pressure p _{3 on the} side plate 2f at the outer diameter of are equal. Similarly, if the second
If the balance hole 2d is not provided, the virtual pressure p ₅ on the main plate 2e side and the pressure p ₄ on the side plate 2f side may be regarded as equal. However, by providing the second balancing holes 2d communicating between the impeller 2 wing is considerably lower pressure than the pressure p ₄ of the side plate 2f side, the pressure p ₂ of the main plate 2e side of the liner portion, the side plate 2f side Is smaller than the pressure p _{4 of} (p ₂ <p ₄ ).

Therefore, the axial thrust force acting on the main plate 2e side is determined by the sum of the pressures p _{1 to} p ₂ ,
The axial thrust force acting on the side plate 2f side is the pressure p
_{Since it} is determined by the total of _{3 to} p ₄ , the axial thrust force acting on the main plate 2e side is reduced by the pressure difference.

Generally, during operation of the canned motor pump, the size of each part is determined so that the rotor is pushed in one of the axial directions and is stabilized. That is, the axial thrust force acting on the rotor 10 due to the pressure difference between the space A and the space B before and after the rotor 10 and the axial thrust force acting on the bolt end located opposite to the suction side due to the pressure in the space C. Or the main plate 2e of the impeller 2
And the axial thrust force acting on the side plate 2f is summed up, and the axial thrust force acts in either direction.

Therefore, when the axial thrust force acts in the suction direction, as described above, the second balance hole 2d is provided in the main plate 2e so that the axial thrust force acting on the main plate 2e side of the impeller 2 is applied. By making it smaller than the axial thrust force acting on the side plate 2f side of the impeller 2, the total axial thrust force can be reduced.

Next, the situation during actual operation of the canned motor pump will be described. Regarding wear, the inner peripheral surface of the first throttle mechanism 20a forming the flow path f, the inner peripheral surface of the second throttle mechanism 20b forming the flow path g, and the can of the rotor 10 forming the flow path c. 12a and stator 13 can 1
Since they are not in contact with 2b, wear other than wear due to the flow rate of the circulating fluid is extremely small. On the other hand, the respective surfaces forming the flow path a, the flow path b, the flow path d, and the flow path e are in contact with each other and relatively rotate, so that the bearing 9 is mainly used.
The wear of the inner peripheral surfaces of a and 9b gradually increases.

However, both the bearing 9a on the impeller side and the bearing 9b on the side opposite to the impeller are provided with spiral grooves and grooves extending along the axial direction on the inner peripheral surface, and the thrust plate 7 is further provided.
Grooves extending in the radial direction are provided on the sliding surfaces with a and 7b, so that even if the inner peripheral surfaces or the end surfaces of the bearings 9a and 9b are worn, these grooves will not be worn. The respective areas of the flow path a, the flow path b, the flow path d, and the flow path e, which influence the magnitude of the pressure in the space E, hardly increase. That is, the pressure in the space E hardly decreases even if the inner peripheral surfaces and the end surfaces of the bearings 9a and 9b are worn.

The first throttle mechanism 2 forming the flow path f
0a inner peripheral surface, and the second throttle mechanism 2 forming the flow path g
Since the inner peripheral surface of 0b is not in contact, there is almost no wear, and therefore the pressure in the space F and the pressure in the space E are almost unchanged.

Therefore, the circulation amount of the first flow hardly changes as the operation time elapses, and the circulation amount of the second flow increases slightly, so that the cooling of the motor section and the Cooling and lubrication of the bearings 9a and 9b can be performed more reliably with the lapse of operating time.

Further, since the pressure in the space F and the pressure in the space E hardly change, the axial thrust force acting on the impeller 2 does not increase. Further, by providing the second balance hole 2d, the pressure acting on the main plate 2e side of the liner portion can be made smaller than the pressure acting on the side plate 2f side, so that the life of the bearings 9a, 9b is shortened. Can be prevented.

Moreover, since the circulation amount of the first flow is almost unchanged, the amount of the pump handling liquid passing through the balance hole 2a of the impeller 2 is also unchanged, and the pump passing through the balance hole 2a of the impeller 2 is not changed. Since there is no change in the flow velocity of the handled liquid, it is possible to prevent the suction performance of the pump from being adversely affected.

In this embodiment, the second balance hole 2d is formed on the side of the main plate 2e of the impeller 2 so as to be suitable when the axial thrust force acts in the suction direction.
However, in the case where the axial thrust force acts on the side opposite to the suction direction, as in the second embodiment of the present invention shown in FIG. 3, the side plate 2f side of the impeller 2 is shown. By providing the second balance hole 2d in the, the total sum of the axial thrust forces can be reduced. In this case, the axial thrust force acting on the side plate 2f side of the impeller 2 is smaller than the axial thrust force acting on the main plate 2e side. This also applies to each of the following embodiments.

FIG. 4 shows a canned motor pump according to a third embodiment of the present invention. In this example, a slightly thick protrusion 3c is formed on the end face of the casing cover 3 on the impeller side.
And the boss portion 2 of the impeller 2
A second diaphragm mechanism 20b is formed between the outer peripheral surface of b and the outer peripheral surface of the protruding portion 3c, and a third noncontact contact between the outer peripheral surface of the protrusion 3c and the inner peripheral surface of the liner 2c on the main plate side of the impeller 2. Aperture mechanism 2
0c is provided. That is, the inner peripheral surface of the projecting portion 3c approaches the outer peripheral surface of the boss portion 2b of the impeller 2 with a slight gap to form the flow path g therein.
The outer peripheral surface approaches the inner peripheral surface of the liner 2c of the impeller 2 with a slight gap, and the flow path h is formed there.

As described above, by providing the third throttle mechanism 20c, in addition to the excellent effects of the first embodiment, the amount of the pump handling liquid passing through the flow path h is reduced, and the pump The efficiency can be further improved.

FIG. 5 shows a canned motor pump according to the fourth embodiment of the present invention. In this example, a solid round bar-shaped rotor 5 is used and a second end cover 11 is provided. A through hole 22 is provided for guiding the circulating liquid flowing along the flow from the space D to the external low pressure portion.

In this embodiment, the circulating liquid flowing along the second flow for cooling the motor portion and cooling and lubricating the bearings 9a, 9b is flown from the space E to the flow passage a. Path b, space A, flow path c, space B, flow path d, flow path e
After passing through the space C and the space C, it is guided to an external low-pressure portion via a pipe connected to the through hole 22.

In the second flow, the temperature of the circulating liquid (liquid handled by the pump) rises to some extent in order to cool the motor part and cool and lubricate the bearings 9a and 9b. When handling liquefied gas or the like, there is a large change in the saturated vapor pressure with a rise in temperature, and there is a danger that this circulating liquid will vaporize. In such a case, returning the circulating fluid to the vicinity of the impeller 2 may cause cavitation at the entrance of the impeller 2. In this example, in addition to the above-mentioned excellent effects, there is an advantage that the suction performance of the pump can be maintained.

In each of the above-mentioned embodiments, plating or thermal spraying may be applied to both or one of the peripheral surfaces constituting the diaphragm mechanism, or the peripheral surface constituting the diaphragm mechanism may be constituted by a replaceable push.

[0054]

As described above, according to the present invention, a pressure liquid chamber for guiding a part of the pressurized liquid after passing through the impeller is provided adjacent to the impeller-side bearing, and the pressure liquid chamber is provided. By configuring the liquid in the chamber to return to the suction side of the impeller, it is possible to prevent the amount of liquid returning from the pressure liquid chamber to the suction side of the impeller from increasing with the lapse of operating time. As a result, the pressure in the pressure liquid chamber can be kept constant at all times, and the cooling of the motor portion and the cooling and lubrication of the bearing can be reliably performed with sufficient lubricating liquid.
At the same time, the axial thrust force acting on one of the main plate and the side plate of the impeller is reduced by the balance hole provided on the outer diameter side of the liner diameter of one of the main slope and the side slope of the impeller to reduce the axial thrust force. Can be reduced.

Particularly, in addition to the pressure liquid chamber, the pressure in the space formed by the casing cover, the sleeve, and the impeller, and the space formed by the casing cover and the impeller can be made substantially constant. By providing a balance hole on the outer diameter side of the liner diameter of the main plate of the impeller, the pressure on the main plate side of the liner section is made smaller than the pressure on the side plate side, and the axial thrust force acting on the impeller is increased. It is possible to prevent the bearing life from being shortened. Further, the amount of the liquid passing through the balance hole of the impeller is made substantially constant, so that the adverse effect on the suction performance of the pump due to the change in the flow velocity of the liquid can be prevented.

It should be noted that a spiral groove and a groove extending along the axial direction are provided on the inner peripheral surfaces of both bearings arranged on both sides of the rotor,
Further, by providing a groove extending along the radial direction also on the sliding surface with the thrust plate, while slightly increasing the circulation amount of the liquid for cooling the motor part and cooling and lubricating the bearing, as the operating time elapses, It is possible to surely perform cooling of the motor part and cooling and lubrication of the bearing.

[Brief description of drawings]

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

FIG. 2 is a diagram showing pressure distributions acting on a main plate side and a side plate side of the impeller in FIG.

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

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

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

FIG. 6 is a sectional view showing a conventional canned motor pump.

7 is a graph showing a pressure measurement result in one space in the canned motor pump shown in FIG.

[Explanation of symbols]

1 pump casing 2 impeller 2a Same balance hole 2b Same boss 2c same liner 2d The second balance hole 2e Same main plate 2f same side plate 3 casing cover 3a Same convex portion 3b, 3c same protrusion 5 rotor 6 distance piece (sleeve) 7a, 7b Thrust plate 8a, 8b shaft sleeve 9a, 9b bearing 14 through holes 20a, 20b, 20c diaphragm mechanism 21 circulation holes 22 through holes A to D space E space (pressure liquid chamber) F, G, H space ah flow path

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomotoshi Hirata 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Tomoyuki Yamazaki 4-1-1 Honfujisawa, Fujisawa-shi, Kanagawa Ceremony company Ebara Densan (72) Inventor Koichi Otake 4-1-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture Ebara Densan (72) Inventor Takayuki Kuronuma 4-chome, Fujisawa, Kanagawa Stock company Ebara Densan (56) Reference JP-A-8-219075 (JP, A) JP-A-1-182600 (JP, A) JP-A-1-315692 (JP, A) JP-A-3- 237293 (JP, A) Actual development 4-65984 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04D 13/06

Claims (5)

(57) [Claims] 1. A can rotor and a rotor to which a pump impeller is fixed are provided, bearings are arranged at both ends of the rotor, and the motor is rotated by a boosted pump handling liquid after passing through the impeller. In a canned motor pump configured to cool a child and a can-sealed motor stator arranged with a gap therebetween, and cool and lubricate each of the bearings, the pump handling on the inner peripheral surface as each of the bearings. With a groove through which liquid flows, a balance hole is provided on the outer diameter side of the liner diameter of one of the main plate and side plate of the impeller, and the pump is provided at a position adjacent to the end face of the impeller-side bearing on the impeller side. A pressure liquid chamber for guiding a part of the liquid to be handled is provided, and the pump liquid to be handled in the pressure liquid chamber is divided into two directions. One pump liquid is used to cool the motor part and both shafts. Cooling and subjected to lubrication, canned motor pump, characterized by being configured to return to the pump suction side via the diaphragm mechanism and the other pump handling liquid. 2. The throttle mechanism is provided between the casing cover and a sleeve that rotates integrally with the rotor, and between the casing cover and the outer peripheral surface of the boss portion of the impeller, respectively. The described canned motor pump. 3. The canned motor pump according to claim 2, wherein a third throttle mechanism is provided between the inner peripheral surface of the liner on the main plate side of the impeller and the pump casing. 4. A through hole is provided inside the rotor for returning the pump handling liquid after cooling the motor part and cooling and lubricating both bearings to the pump suction side. The canned motor pump according to any one of 1 to 3. 5. A pump casing containing a rotor and a stator of the motor unit, the pump handling liquid after cooling the motor unit and cooling and lubricating both bearings flows out of the pump casing. The canned motor pump according to any one of claims 1 to 3, wherein a through hole is provided.