JP2003184787A - Centrifugal motor pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal motor pump having high efficiency and a long life and preventing the occurrence of cavitation even when operating at a high speed. <P>SOLUTION: This centrifugal motor pump has a motor rotor 6 and a motor rotor can 6a arranged integrally with an impeller 5 inside a pump chamber constituted of a pump casing 1 and a motor stator case 2. A pump casing side wall surface of the impeller 5 and the corresponding pump casing wall surface are formed in conical or approximately conical shapes. A recessed groove 5c for generating dynamic pressure is formed on the pump casing side wall surface of the impeller 5. A motor stator side wall surface of the motor rotor can 6a and the corresponding motor stator case wall surface are formed in flat or conical or approximately conical shapes. A recessed groove 6b for generating dynamic pressure is formed on the motor stator side wall surface of the motor rotor can 6a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal motor pump, and more particularly to a centrifugal motor pump capable of achieving high efficiency and long life and suppressing the occurrence of cavitation when operating at high speed.

[0002]

14 to 16 are views showing a general structure of a centrifugal motor pump of this type. FIG. 14 is a sectional view, FIG. 15 is a view showing a section A of FIG. 14, and FIG. Figure 1
It is a figure of the suction part seen from B of FIG. As shown in FIG. 14, an impeller 5 and a motor rotor 6 are arranged integrally with the main shaft 4 in a pump chamber formed of a motor stator case 2 into which a pump casing 1 and a motor stator 3 are fitted. In order to protect the motor rotor 6 from corrosion and erosion due to the pump handling liquid, a motor rotor can 6a is fixed to the motor rotor 6 to cover the outer surface of the motor rotor 6 on the side of the stator case 2.

A plurality of suction holes 1a are formed in the pump casing 1 in the axial direction, and these suction holes 1a constitute the suction passage of the pump. The pump handling liquid that has flowed in from the suction port 1s passes through the suction hole 1a, the impeller 5, and the volute 1b of the pump casing 1 and reaches the discharge port. Then, by a series of pump actions, the radial thrust and axial thrust acting on the rotating body constituted by the main shaft 4, the impeller 5, the motor rotor 6, and the motor rotor can 6a are
Bearings 7a and 7b arranged in the pump casing 1 and the motor stator case 2, and a thrust plate 8 arranged in the main shaft 4.
It is supported by a and 8b.

The impeller 5 shown in FIGS. 14 and 15 is a semi-open type impeller having no side plate on the suction port side, but as the impeller 5, as shown in FIG. 17, a side plate is provided on the suction port side. A closed type impeller with 5a may be used in some cases. In the centrifugal motor pump shown in FIGS. 14 to 17,
The magnetic field generated by the motor stator 3 gives a rotational torque to the motor rotor 6, and the main shaft 4, the impeller 5 and the motor rotor can 6a integrally fixed to the motor rotor 6
It rotates at the same rotation speed as the motor rotor 6. The rotation of the impeller 5 gives velocity energy to the pump handling liquid,
By decelerating the speed of the pump handling liquid in the volute 1b of the pump casing 1, it is converted into pressure energy.

In centrifugal pumps, the radial thrust acting on the impeller can be calculated for specific pumps whose performance is known, as the dimensions of the pump components are determined. For example, A. J. Stepano
ff “Centrifugal and Axial”
According to "Flow PUMPS (1948)", when the speed reducing structure in the pump casing is a volute, the radial thrust can be calculated by the following equation. Fr = K × H × ρ × D × B × ξ ... …… Equation 1 K = Ko × {1- (Q / Qbep) ² } ………… Equation 2 where Fr: radial thrust acting on impeller K: Radial thrust coefficient H: Total pump head ρ: Density of pump handling liquid D: Outer diameter of impeller B: Impeller outlet width (sum of passages, main plate and side plates) ξ: Pump casing In the case of a single volute as shown in FIG. 15, ξ = 1 Ko: radial thrust coefficient Q at deadline (Q = 0) Q: pump operating flow rate Qbep: flow rate at maximum efficiency point of pump.

Since the total head is proportional to the square of the rotational speed of the pump, from Equation 1, the radial thrust is proportional to the square of the rotational speed of the pump. Similarly, the axial thrust acting on the impeller of the centrifugal pump can be calculated from the above-mentioned book. According to it, the calculation formula is different between the semi-open type and the closed type of the impeller.

In the case of the semi-open type impeller shown in FIG. 18, the axial thrust can be calculated by the following equation. The axial thrust T _f acting on the suction side surface is T _f = (A ₂ −A ₁ ) × H _v / 2 × ρ ... Equation 3 The axial thrust T _b acting on the anti-suction side surface is T _b = ^{_{a 2 × {H v -u 2}} 2 / (8 × 2 × g)} × ρ ......... formula 4 axial thrust T of the _{net, T = T b -T f =} a 2 × {H v -u a ^{_{2 2 / (8 × 2 ×}} g)} × ρ- (a 2 -A 1) × H v / 2 × ρ ......... formula 5 wherein, _{H v:} total head at the impeller outlet _{u 2:} blade Circumferential velocity g at the vehicle outlet: Gravity acceleration ρ: Density of pump handling liquid A ₁ : Impeller side surface area (A _{1 in} FIG. 18) A ₂ : Impeller side surface area (A _{2 in} FIG. 18)

For a particular pump,
A₁, A_Two, G, ρ are constant, so A_Two× ρ = K1,8
× 2 × g = K2, (A_Two-A₁) / 2 x ρ = K3
For example, Equation 5 becomes     T = K1 × (H_v-U_Two ^Two/ K2) -K3 x H_v           = K1 x H_v-U_Two ^TwoX K1 / K2-K3 x H_v       = (K1-K3) x H_v-U_Two ^Two× K1 / K2 ……… Equation 6 Further, in the equation 6, K1-K3 = K4, K1 / K2 =
If we say K5, Equation 6 becomes     T = K4 × H_v-K5xu_Two ^Two             ……… Equation 7 Becomes Here, K1 to K7 are all constant.

Assuming that the rotation speed of the above specific pump is 2
If doubled, H_vIs 4 times, u_TwoDoubles.
At this time, the net axial thrust T2 is T2 = K4 × (4 × H_v) -K5 × (2 × u_Two)^Two = 4 x (K4 x H_v-K5xu_Two ^Two) = 4 × T = 2^Two× T And the net axial thrust is proportional to the square of the rotation speed.
It

On the other hand, in the case of the closed type impeller shown in FIG. 19, the axial thrust can be calculated by the following equation. Axial thrust _{T f} acting on the suction _{side, T f = (A 2 -A} 1) × the ^{_{{H v -u 2 2 / (}} 8 × 2 × g)} × ρ ......... formula 8 anti suction side The acting axial thrust T _b is T _b = A ₂ × {H _v −u ₂ ² / (8 × 2 × g)} × ρ (Equation 9) The net axial thrust T is T = T _b −T _f = A ₁ × {H _v −u ₂ ² / (8 × 2 × g)} × ρ (Equation 10) where, H _v : total head u _{2 at the} impeller outlet part: ₂ : impeller outlet part Circumferential velocity g: Gravity acceleration ρ: Density of pump handling liquid A ₁ : Area of impeller side surface (A _{1 in} FIG. 19) A ₂ : Area of impeller side surface (A _{2 in} FIG. 19) Semi-open type impeller As in the case of, since A ₁ , g, ρ in Equation 10 is constant for a specific pump,
If A ₁ × ρ = K6 and 8 × 2 × g = K7, then Equation 10
Is T = K6 × (H _v −u ₂ ² / K7) ...

Assuming that the rotation speed of the above specific pump is 2
If it is doubled, H _v is 4 times and u ₂ is doubled.
The net axial thrust T2 at this time is T2 = K6 × {(4 × H _v ) − (2 × u ₂ ) ² / K7} = 4 × {K6 × (H v -u 2 2 / K7)} = a ^{4 × T = 2 2 × T} , the axial thrust of the net is proportional to the square of the rotational speed. As shown in the above formula, the radial thrust and axial thrust acting on the impeller are proportional to the square of the rotational speed of the pump.

As described above, when the centrifugal motor pump is operated at a high speed, the radial thrust force and the axial thrust force acting on the rotating body constituted by the main shaft 4, the impeller 5, the motor rotor 6 and the motor rotor can 6a are as follows. It is proportional to the square of the rotation speed. In high-speed operation, the increased thrust increases the bearing load per unit area acting on the bearings 7a and 7b and the thrust plates 8a and 8b. For that purpose, the bearing 7
The inner and outer diameters of a and 7b are increased, and the thrust plate 8
By increasing the outer diameters of a and 8b to increase the pressure receiving area, it is possible to cope with an increase in bearing load.

However, when the inner diameter and outer diameter of the bearing and the thrust plate are increased, the peripheral speed (product of diameter and rotational speed) also increases. Depending on the materials of the bearings 7a and 7b and the thrust plates 8a and 8b, the permissible peripheral speeds have their respective limits, and therefore, when operating at high speed, the rotational speed of the motor pump also has a limit. That is, when the main shaft 4, the impeller 5, the motor rotor 6, and the motor rotor can 6a are below the permissible peripheral speeds of their materials, the permissible maximum rotational speed of the motor pump is the bearings 7a, 7b and the thrust plates 8a, 8
It depends on the permissible peripheral speed of b.

Next, the bearings 7a, 7b and the thrust plate 8
a, 8b are sliding by friction loss h _f of the material, the dynamic friction coefficient of the sliding surface is proportional to the bearing load and the peripheral speed can be calculated by the following equation. h _f = μ × F × v ・ ・ ・ Equation 12 where μ : Dynamic friction coefficient F of sliding surface : Bearing load v of bearings and thrust plates : Peripheral speed of bearing and thrust plate

In equation 12, the dynamic friction coefficient μ is
Even if the material of the thrust plate is specified, there will be no gap between these sliding surfaces.
It changes depending on the temperature and surface pressure of the existing film.
So I can't specify it. However, in centrifugal motor pumps
Between these sliding surfaces when the motor pump is operating.
Is the sliding surface because the liquid handled by the pump is constantly circulating.
The temperature of the intervening film may be considered constant and in fact
Determines that the coefficient of dynamic friction μ is a constant value. Also, bearing load
F is proportional to the square of the rotation speed of the motor pump,
v is proportional to the rotation speed of the motor pump. That is,
By sliding bearings 7a, 7b and thrust plates 8a, 8b
Friction loss h _fIs proportional to the cube of the rotation speed of the motor pump
To do.

Furthermore, since the pressure loss in the suction hole 1a of the pump casing 1 is proportional to the square of the flow velocity here, that is, the square of the flow rate, a pressure drop occurs at the inlet of the impeller 5 and cavitation occurs. Easier to do. In order to prevent the occurrence of cavitation, it is preferable that the inlet of the impeller 5 be free of obstacles such as the suction hole 1a and the bearing 7a.

As described above, this type of centrifugal motor pump has the following problems when operating at high speed. (1) The maximum permissible rotational speed of the motor pump is limited due to the limited peripheral speed of the bearing material. (2) Since the friction loss due to sliding of the bearing is increased, the pump efficiency is reduced and the bearing life is shortened. (3) Cavitation is likely to occur because the suction hole and the bearing are arranged in the suction portion.

As a means for solving these problems, there is a magnetic bearing mounting type motor pump in which an active magnetic bearing is mounted so that the rotating body can be operated in a non-contact state. In this motor pump, since the rotating body can be supported in a non-contact manner even at high speed operation, the friction loss due to the sliding of the bearing is about 1/10 of that of the conventional slide bearing, which improves the pump efficiency and extends the life of the bearing. It is possible. However, an electromagnet that acts as a bearing,
And a controller (control circuit) for adjusting the electric current of the electromagnet to hold the rotating body in a non-contact manner,
Due to the consumed power, the efficiency of the motor pump as a whole was reduced.

As another means, there is a dynamic pressure bearing type motor pump which employs a dynamic pressure bearing as a bearing and can operate a rotating body in a non-contact state. In this motor pump, since the rotating body can be supported in a non-contact manner even at high speed rotation, it is possible to improve pump efficiency and extend the life of the bearing. However, the bearing that supports the radial thrust and the axial thrust that increases in proportion to the square of the rotation speed of the motor pump does not function at one location on the non-suction side. Therefore, in this model, it is necessary to provide a suction hole, a bearing, etc. on the suction side, and it is not possible to suppress the occurrence of cavitation.

[0020]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is possible to achieve high efficiency and long life even when operating at high speed, and to suppress the occurrence of cavitation. An object is to provide a centrifugal motor pump.

[0021]

In order to achieve the above-mentioned object, the present invention provides a centrifugal motor in which a motor rotor and a motor rotor can are integrated with an impeller in a pump chamber constituted by a pump casing and a motor stator case. In the pump, the pump casing side wall surface of the impeller and the opposing pump casing wall surface are formed into a conical shape or a substantially conical shape, and a concave groove for generating dynamic pressure is provided on the pump casing side wall surface of the impeller. The motor stator side wall surface and the opposing motor stator case wall surface are formed in a planar shape, a conical shape, or a substantially conical shape, and a concave groove for generating a dynamic pressure is provided on the motor stator side wall surface of the motor rotor can. Is.

According to the present invention, dynamic pressure is generated on the side wall surface of the pump casing and the side wall surface of the motor stator case of the rotating body, so that the rotating body can be operated in a non-contact state. Efficiency and long life can be achieved, and there is no need to install suction holes or bearings on the suction side.
The occurrence of cavitation can be suppressed. In a preferred aspect of the present invention, a permanent magnet or a magnetic material is arranged on a wall surface of the pump casing facing the impeller. As a result, the impeller is sucked to the suction side, and the impeller is easily supported in a non-contact manner.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views showing a centrifugal motor pump according to a first embodiment of the present invention. FIG. 1 is a cross-sectional view, FIG. 2 is a view showing a cross-section C of FIG. 1, and FIGS. 1
It is a figure which shows the cross section D in. The same or corresponding parts as those of the conventional example are designated by the same reference numerals, and the duplicated description thereof will be omitted.

As shown in FIG. 1, an impeller 5 and a motor rotor 6 which are integrally formed are arranged in a pump chamber composed of a pump casing 1 and a motor stator case 2 into which a motor stator 3 is fitted. In order to protect the motor rotor 6 from corrosion and erosion due to the pump handling liquid, a motor rotor can 6a is fixed to the motor rotor 6 to cover the outer surface of the motor rotor 6 on the side of the stator case 2. Figure 1
In the motor pump shown in (1), there is no bearing or thrust plate as in the conventional example, and the wall surface of the impeller 5 on the pump casing 1 side and the opposing pump casing wall surface are conical or substantially conical. A conical apex P is formed at an angle of 5d. On the other hand, the motor rotor can 6
The wall surface of the motor stator 3 side of a and the wall surface of the motor stator case 2 facing each other are formed in a flat shape.

As shown in FIG. 2, the surface of the blade 5b of the impeller 5 is provided with a concave groove 5c for generating dynamic pressure.
Further, as shown in FIGS. 3 and 4, a concave groove 6b for generating dynamic pressure is also provided on the surface of the motor rotor can 6a. FIG. 3 shows an example of a groove on the surface of the motor rotor can, and FIG. 4 shows another example of a groove on the surface of the motor rotor can. Axial gaps δ1 and δ2 are formed between the pump casing 1 and the impeller 5, and an axial gap δ is formed between the motor rotor can 6a and the motor stator case 2.
3 is formed.

The magnitude of the dynamic pressure generated on the side wall surface of the pump casing 1 and the side wall surface of the motor rotor 6 of the impeller 5 depends on the sizes of the gaps δ1, δ2 and δ3, respectively. The smaller the clearances δ1, δ2, and δ3, the greater the dynamic pressure. Moreover, in FIG. 3, although the concave groove 6b has one line,
In FIG. 4, the groove 6b has two grooves, and the area where dynamic pressure is generated can be increased by increasing the number of grooves.

The impeller 5 shown in FIGS. 1 and 2 is a semi-open type having no side plate on the suction port side, but as shown in FIG. 5, it is a closed type having a side plate 5a on the suction port side. May be used. In this case, as shown in FIG. 6, the concave groove 5c for generating dynamic pressure is provided on the outer surface of the side plate 5a.

In the centrifugal motor pump configured as shown in FIGS. 1 to 6, before starting, for example, in the case of installation in which the suction port 1s is directly above, the impeller 5, the motor rotor 6, and the motor rotor can 6a. The rotating body constituted by is mounted on the stator case 2. When the motor pump is started and the pressure in the pump chamber rises, the pressure distribution in the impeller 5 becomes that shown in FIG. 7 for the semi-open type and that shown in FIG. 8 for the closed type. Therefore, the net axial thrust acting on the rotating body is larger on the wall surface on the motor rotor can 6a side than on the wall surface on the impeller 5 side. Then, the rotor is pushed toward the suction side, the gaps δ1 and δ2 are reduced, and the gap δ3 is increased, so that the dynamic pressure on the wall surface on the impeller 5 side is increased. The axial thrust force acting on the impeller 5 is reversed, and the wall surface on the impeller 5 side is larger than the wall surface on the motor rotor can 6a side.

On the other hand, in the radial direction, the radial total of the radial thrust Fr acting on the impeller and the load (applied to the impeller) generated by the dynamic pressure must be balanced. When the radial thrust Fr acts on the rotating body, the gap δ1 or δ2 in the direction opposite to the direction of Fr becomes small, and therefore the radial component force of the load P2 generated by the dynamic pressure shown in FIG. The gap R1 or R2 decreases until the force R2 increases and balances with the radial thrust Fr. When the specified rotation speed is reached, the operating point becomes constant,
The direction and magnitude of the radial thrust Fr become constant, and the motor pump can be operated without contact at a position where the radial thrust Fr acting on the rotating body and the reaction force R2 are balanced.

Next, in a case where the suction port 1s is horizontally horizontal and the discharge port is directly above, the rotor is in a state of δ2 = 0 and δ3 = 0 in FIG. 1 before starting. . When the motor pump is started and the pressure in the pump chamber rises, the pressure distribution in the impeller 5 becomes that shown in FIG. 7 for the semi-open type and that shown in FIG. 8 for the closed type. Therefore, the net axial thrust acting on the rotating body is greater on the wall surface on the motor rotor can 6a side than on the wall surface on the impeller 5 side.

On the other hand, in the radial direction, it is necessary to balance the resultant force of the radial thrust Fr and the mass of the rotating body with the radial reaction force R2 of the load P2 generated by the dynamic pressure.
Until the resultant force is balanced, the clearance δ1 or δ2 becomes smaller, and the reaction force R2 becomes larger. When the specified rotation speed is reached, the operating point becomes constant, the direction and magnitude of the radial thrust Fr become constant, and the radial thrust Fr acting on the rotating body, the mass W, and the reaction force R2 are balanced. In position, the motor pump can be operated contactless.

The conditions under which the motor pump can be operated in a non-contact manner will be described below using equations. During operation of the motor pump, the following six types of external forces act on the rotating body. W: Mass of rotating body (excluding buoyancy equivalent to volume) M: Magnetic attraction force acting on the motor rotor F1: Dynamic pressure load acting on the impeller side wall surface F2: Dynamic pressure acting on the motor stator side wall surface Load Fr: Radial thrust T: Net axial thrust

As shown in FIGS. 10 (a) and 10 (b), the center of rotation of the rotating body is O, and the points O are separated from each other by 90 °, and the three axes of X, Y, and Z are arranged. Assuming orthogonal coordinate axes, these external forces have a certain fixed direction and distance with respect to the point O and the three axes X, Y, and Z. These external forces are decomposed into three component forces in parallel to the three axes,
These component forces are balanced for each of the three axes,
If the moments of these component forces and the distance from the point O are balanced with respect to each of the three axes, the rotating body can be supported in a non-contact manner.

Here, the subscripts of the three component forces are _X , _Y and _Z, and the component force distances from the point O to the three axes are _XL , _YL and _ZL . The equilibrium formula of component force for each of the three axes is: W _X + M _X + F1 _X + F2 _X + Fr _X + T _X = 0 ... Formula 13 On the Y axis, W _Y + M _Y + F1 _Y + F2 _Y + Fr _Y + T _Y = 0 ... Formula 14 On the Z axis, W _Z + M _Z + F1 _Z + F2 _Z + Fr _Z + T _Z = 0 Formula 15

The moment balance equation is as follows:     W_X× W_XL+ M_X× M_XL+ F1_X× F1_XL+ F2_X× F2_XL     + Fr_X× Fr_XL+ T_X× T_XL= 0 ………… Equation 16 On the Y axis,     W_Y× W_YL+ M_Y× M_YL+ F1_Y× F1_YL+ F2_Y× F2_YL     + Fr_Y× Fr_YL+ T_Y× T_YL= 0 ... Formula 17 On the Z axis,     W_Z× W_ZL+ M_Z× M_ZL+ F1_Z× F1_ZL+ F2_Z× F2_ZL     + Fr_Z× Fr_ZL+ T_Z× T_ZL= 0 ... Formula 18 In order to satisfy the above expressions 13 to 18, the motor po
The dimensions of the pump may be determined.

Generally, a magnetic material is used as the material of the motor rotor, but in order to improve the efficiency of the motor alone, the motor rotor can 6a may be an extremely thin plate or a permanent magnet may be used. In such a case, as shown in FIG. 11, the number of recessed grooves 6b is increased to increase the area for generating dynamic pressure on the motor rotor can 6a side, or as shown in FIG. When the permanent magnet or the magnetic material 1c is arranged on the wall surface facing the impeller 5 surface and the rotor is attracted to the suction side, the rotor can be easily supported in a non-contact manner. If the motor stator case 2 and the motor rotor can 6a are made of a material having a small coefficient of static friction, the motor pump can be started easily. The material having a small coefficient of static friction is, for example, ceramics whose surface is polished or polyetheretherketone.

Further, as shown in FIG. 13, if the motor rotor can 6a side is also formed in a conical shape or a substantially conical shape, the reaction force can be increased with respect to a radial load such as a radial thrust. Since the rotating body is in contact with the pump casing and the motor stator case before starting the motor pump, for example, if the circuit configuration allows the motor to operate at low speed at startup, the amount of wear due to sliding will be reduced. It can be reduced.

[0038]

As described above, according to the present invention,
Since the rotating body can be operated in a non-contact state in the axial direction and the radial direction, friction loss can be reduced, high efficiency and long life can be achieved, and it is not necessary to dispose a suction hole or a bearing on the suction side. The occurrence of cavitation can be suppressed.

[Brief description of drawings]

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

FIG. 2 is a view showing a cross section C in FIG.

FIG. 3 is a diagram showing a cross section D in FIG. 1.

FIG. 4 is a diagram showing a cross section D in FIG. 1.

FIG. 5 is a view showing a closed type impeller.

FIG. 6 is a view showing a side plate of a closed type impeller.

FIG. 7 is a diagram showing a pressure distribution of a semi-open type impeller.

FIG. 8 is a diagram showing a pressure distribution of a closed type impeller.

FIG. 9 is a diagram showing a load and a component force due to dynamic pressure.

FIG. 10 is a diagram showing three directions in the motor pump.

FIG. 11 is a diagram showing a motor rotor can in which the number of grooves is increased.

FIG. 12 is a view in which a permanent magnet or a magnetic material is put in the pump casing.

FIG. 13 is a sectional view showing a centrifugal motor pump according to a second embodiment of the present invention.

FIG. 14 is a cross-sectional view showing a conventional centrifugal motor pump.

15 is a diagram showing a cross section A in FIG.

16 is a diagram viewed from B in FIG. 14. FIG.

FIG. 17 is a view showing a closed type impeller.

FIG. 18 is a diagram illustrating an area of a side surface of an impeller.

FIG. 19 is a diagram illustrating an area of a side surface of an impeller.

[Explanation of symbols]

1 pump casing 1a Suction hole 1b volute 1c Permanent magnet or magnetic material 1s suction port 2 motor stator case 3 motor stator 4 spindles 5 impeller 5a side plate 5c groove 6 motor rotor 6a Motor rotor can 7a, 7b bearings 8a, 8b thrust plate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F04D 29/42 F04D 29/42 AE 29/66 29/66 BF term (reference) 3H020 BA10 BA26 3H022 AA01 BA02 CA50 DA08 3H033 AA01 BB01 BB06 CC01 CC03 DD06 EE07 EE11 3H034 AA01 BB01 BB06 CC04 DD01 EE07 EE09

Claims (2)

[Claims] 1. A centrifugal motor pump in which a motor rotor and a motor rotor can are integrated with an impeller in a pump chamber formed by a pump casing and a motor stator case. In the centrifugal motor pump, the impeller pump casing side wall surface and the opposing pump casing wall surface are provided. Is formed into a conical shape or a substantially conical shape, and a concave groove for generating dynamic pressure is provided on the pump casing side wall surface of the impeller, and the motor stator side wall surface of the motor rotor can and the facing motor stator case wall surface are flat or conical A centrifugal motor pump, which is formed in a substantially conical shape, and is provided with a concave groove for generating a dynamic pressure on a side wall surface of a motor stator of the motor rotor can. 2. The centrifugal motor pump according to claim 1, wherein a permanent magnet or a magnetic material is provided on a wall surface of the pump casing facing the impeller.