JPH0612790U - Cooling water circulation type pump - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a cooling water circulation pump that prevents collision between return water of cooling water and suction water sucked into the pump and reduces collision noise. [Structure] An impeller 10 in a pump casing 1 is driven by a drive shaft 15 rotated by a motor 20, and a part of high-pressure water in the pump casing is driven by a can 30 of the motor.
In a pump that introduces the cooling water into cooling water, guides the cooling water through the return hole 34 formed in the drive shaft, and discharges the cooling water to the low-pressure side on the suction side, the cooling water is discharged to the drive shaft 15 through the return hole of the drive shaft. The guide portion 40 is provided to change the cooling water to be guided along the flow direction of the water sucked from the suction port. The cooling water returned from the return hole of the drive shaft has its direction corrected by the guide portion so as to follow the flow direction of the suction water. To reduce.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cooling water circulation pump in which an impeller is driven by a canned motor and this canned motor is forcibly cooled by cooling water.

[0002]

[Prior art]

 In a multistage centrifugal pump (also referred to as a turbine pump), a canned motor is used to rotationally drive an impeller housed in a casing.

A canned motor blocks noise around the rotor such as a humming noise by covering the rotor with a can. A pump using such a canned motor is effective as a low noise type pump. Is.

By the way, when the rotor is covered with the above-mentioned can in order to prevent the noise of the motor from leaking to the outside, the heat generated in the can is also prevented from being released, and the temperature in the can rises. There is a defect. In order to prevent this, a structure in which the motor is water cooled is adopted. A conventional water-cooled motor pump of this type will be described with reference to FIG.

In the figure, 1 is a pump casing, and 2 is a casing cover that covers the back surface of the pump casing 1. A suction port 3 is opened at the front end of the pump casing 1, and a suction port flange 4 is attached to the suction port 3. A discharge port 5 is opened at the upper end of the pump casing 1, and a discharge port flange 6 is attached to this discharge port 5.

In the pump casing 1, a first stage guide vane 7 and a second stage guide vane 8 are fixed together by bolts 9 to the casing cover 2. A first-stage impeller 10 and a second-stage impeller 11 are rotatably housed in these first-stage guide vanes 7 and second-stage guide vanes 8, respectively. The first-stage impeller 10 and the second-stage impeller 11 are attached to the drive shaft 15, and rotate integrally with the rotation of the drive shaft 15. In this case, the space sleeve 12 is inserted between the first-stage impeller 10 and the second-stage impeller 11, and the first-stage impeller 10 and the sleeves 13 and 2 are secured by the tightening nut 13 screwed onto the tip of the drive shaft 15. The stepped impeller 11 is fixed to the drive shaft 15.

A canned motor 20 is connected to the back surface of the casing cover 2. In the canned motor 20, the front end and the rear end of the motor casing 21 are liquid-tightly closed by the end plates 22 and 23, respectively, and the rear end of the drive shaft 15 is introduced therein. The drive shaft 15 also serves as a motor shaft, and is rotatably supported by bearings 24 and 25 on the end plates 22 and 23, respectively. In addition, 26 is a thrust bearing. A rotor 27 is fixed around the drive shaft 15, and a stator 28 is attached to the inner surface of the motor casing 21 so as to face the rotor 27. A can 30 is provided on the inner peripheral surface of the stator 28 to partition the inside of the motor into the inner and outer radial directions. The inside of the motor is divided in the radial direction by the can 30 so as to be liquid-tight, and the rotor 27 can freely rotate in the internal space.

This internal space is a water cooling chamber 31. High-pressure water pressurized by the impeller 11 is introduced into the water cooling chamber 31 to cool the inner peripheral surfaces of the rotor 27 and the can 30. The front end plate 22 is formed with an introduction hole 32 for introducing the high pressure water pressurized by the second-stage impeller 11 into the water cooling chamber 31. A guide hole 33 for returning the cooling water in the cooling chamber 31 to the low pressure side of the pump is formed in the rear end plate 23, and the guide hole 33 faces the rear end surface of the drive shaft 15. A cooling water return hole 34 is formed through the drive shaft 15 along the center line. The return hole 34 communicates with a recirculation hole 35 opened on the front end face of the drive shaft 15, and the recirculation hole 35 is opened toward the suction port 3.

In the multi-stage centrifugal pump having such a configuration, the drive shaft 15 is rotated by the rotation of the motor 20, so that the first-stage impeller 10 and the second-stage impeller 11 are respectively the first-stage guide vanes 7 and the second-stage impellers. Rotate in the eye guide vane 8. The rotation of the impellers 10 and 11 sucks water from the suction pipe connected to the front surface, connects the water upward, and discharges the water toward the discharge pipe. That is, the water in the suction pipe is sucked from the suction port 3 through the central portion of the impeller 10 to the first-stage guide vanes 7 as the first-stage impeller 10 rotates, and inside the first-stage guide vanes 7. Pressurized. The pressurized water is sucked into the second-stage guide vane 8 from the central portion of the second-stage impeller 11, and is pressurized in the second-stage guide vane 8. This pressurized water is sent to the discharge pipe side through the discharge port 6.

In the motor 20 of such a multi-stage centrifugal pump, since the can 30 is installed in the motor casing 21, the noise of the motor 20 is reduced from leaking to the outside and low noise becomes possible. .

During operation of the pump, high-pressure water pressurized by the second-stage impeller 11 in the pump casing 1 is introduced from the introduction hole 32 into the water cooling chamber 31 partitioned by the can 30. The cooling water contacts the inner peripheral surfaces of the rotor 27 and the can 30 in the water cooling chamber 31 to cool them. The cooling water in the cooling chamber 31 is sent to the return hole 34 formed in the drive shaft 15 through the outlet hole 33, and from the return hole 34 to the return hole 35 opened in the front end surface of the drive shaft 15 to the pump casing 1. It is discharged to the low pressure part, that is, near the suction port 3.

The cooling water discharged in the vicinity of the suction port 3 is mixed with the new water sucked from the suction pipe, sucked into the first stage guide vane 7 through the first stage impeller 10, and the first gas After being pressurized in the id vane 7, it is sucked by the second stage guide vane 8 from the second stage impeller 11 and is pressurized in the second stage guide vane 8 and discharged from the discharge port 6. Then, a part of the high-pressure water pressurized in the second-stage guide vane 8 is sent to the water cooling chamber 31 again to cool the motor 20.

That is, the introduction hole 32, the water cooling chamber 31, the derivation hole 33, the return hole 34 formed in the drive shaft 15, and the return hole 35 constitute a circulation path of cooling water, and the water flowing through this circulation path is used. The motor 20 is forcibly cooled. Therefore, it is possible to prevent the temperature inside the motor 20 from rising and prevent a problem such as seizure of the motor.

[0014]

[Problems to be solved by the device]

 However, in the case of the conventional structure shown in FIG. 3, the cooling water in the cooling chamber 31 is discharged from the return hole 34 formed in the drive shaft 15 through the outlet hole 33 to the low pressure portion of the pump casing 1 through the return hole 35. However, the reflux hole 35 formed at the front end of the drive shaft 15 is opened toward the suction port 3 of the pump casing 1, and therefore the water discharged from the reflux hole 35 is sucked into the suction port 3. Face-to-face collision with suction water sucked from.

Such collision of water with water causes a collision noise, and since the pressure of the cooling water is high, there is a drawback that the suction water is disturbed and the suction characteristic of the pump is deteriorated. In particular, despite the fact that this type of pump was developed as a low-noise type, the generation of the above-mentioned water collision noise has a problem that impedes the above-mentioned initial purpose.

The present invention has been made in view of the above circumstances, and its purpose is to prevent collision between the return water of the cooling water and the suction water sucked into the pump, reduce the collision noise, and reduce the noise. It is intended to provide a cooling water circulation type pump that can realize noise reduction.

[0017]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention drives an impeller housed in a pump casing by a drive shaft integrally formed with a motor shaft of a canned motor, sucks it from a suction port of the pump casing, and pressurizes it with a high pressure. A part of the water is introduced into the can of the motor as cooling water, and this cooling water is guided through the return hole formed in the drive shaft and discharged to the low pressure part on the suction side of the impeller, and the discharged cooling water. In the cooling water circulation type pump, which is designed to mix with the suction water introduced from the suction port,

The drive shaft is provided with a guide portion for changing the cooling water discharged from the return hole of the drive shaft so as to follow the flow direction of the intake water sucked from the suction port of the pump casing. To do.

[0019]

[Action]

 In the above configuration, the cooling water returned through the return hole of the drive shaft is internally adjusted in its discharge direction so as to be along the flow direction of the water sucked from the suction port, so that the return water is the suction water. Will no longer collide with.

[0020]

【Example】

 The present invention will be described below based on an embodiment shown in FIGS. 1 and 2.

This embodiment shows an example applied to a multi-stage centrifugal pump (turbine pump), and since it may be similar to the conventional configuration shown in FIG. 3 in most points, the same parts are designated by the same reference numerals. The description will be omitted and only the points different from the conventional one will be described.

That is, in this embodiment, the guide member 40 is provided at the inner end of the drive shaft 15. This guide member 40 is a modification of the conventional tightening nut 13. The tightening nut has a cap nut structure, and one end of this nut, that is, the guide member, is connected to the return hole 35 formed in the drive shaft 15, A guide hole 41 is formed, the other end of which is open obliquely rearward. The opening direction of the guide hole 41 is toward the central suction port of the first-stage impeller 10 (the central opening of the first-stage guide vane), so that the cooling water returned through the return hole 34 of the drive shaft 15 is returned. The recirculation water is discharged from the recirculation hole 35 toward the first stage guide vane 7 through the guide hole 41 of the guide member 40. This direction is almost the same as the flow of suction water introduced from the suction port 3 of the pump casing 1.

Therefore, according to such a configuration, the cooling water that cools the motor 20 and is returned to the pump casing 1 is introduced from the guide hole 41 of the guide member 40 through the suction port 3 of the pump casing 1. It is discharged in almost the same direction as the flow of suction water. Therefore, the return water of the cooling water and the suction water sucked from the suction port 3 do not collide head-on with each other, so that the collision noise of water can be prevented.

Further, since the return water of the cooling water flows into the impeller 10 along the flow of the suction water sucked by the impeller 10, there is no turbulent flow in this inflow water, and the impeller 10 has good suction characteristics. Become Pump performance is improved. The present invention is not limited to the above embodiment.

That is, in the case of the above embodiment, an example applied to a multistage centrifugal pump (turbine pump) was shown, but since the present invention has a structure for returning the cooling water of the motor to the low pressure side, the pump is a multistage However, it may be a single-stage type. The guide member 40 is not limited to the common member with the tightening nut, and may be configured separately from the tightening nut.

Furthermore, the return water guide hole 41 is not limited to being correctly oriented in the same direction as the flow of the suction water, and in short, the flow direction of the return water and the flow direction of the suction water are 90 ° to each other. In such a case, it is feasible because the collision noise is extremely reduced when the two flows intersect at an angle of 90 ° or less.

[0027]

[Effect of device]

 As described above, according to the present invention, the return direction of the cooling water returned through the return hole of the drive shaft is corrected by the guide portion so as to follow the flow direction of the water sucked from the suction port. Will flow almost in the same direction as the suction water, and they will not collide with each other. Therefore, the collision noise of water is not generated or becomes small, and the noise is reduced. Furthermore, the collision of these waters reduces turbulence, improves suction characteristics, and improves pump performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a multistage centrifugal pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the embodiment.

FIG. 3 is a cross-sectional view of a multi-stage centrifugal pump showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pump casing, 2 ... Casing cover, 3 ... Suction port, 5 ... Discharge port, 6, 7 ... Guide vane, 10, 11
... impeller, 15 ... drive shaft, 20 ... motor, 21 ... motor casing, 27 ... rotor, 28 ... stator, 30 ...
Can 31, 31 ... Water cooling chamber, 32 ... Inlet hole, 33 ... Outlet hole,
34 ... Return hole, 35 ... Reflux hole, 40 ... Guide member, 41 ...
Guide hole.

Claims (1)

[Scope of utility model registration request] 1. An impeller housed in a pump casing is driven by a drive shaft integrally formed with a motor shaft of a canned motor, and a part of high-pressure water sucked from a suction port of the pump casing and pressurized by the impeller is driven. It is introduced into the can of the motor as cooling water, and the cooling water is guided through the return hole formed in the drive shaft and discharged to the low pressure portion on the suction side of the impeller, and the discharged cooling water is introduced from the suction port. In the cooling water circulation pump adapted to be mixed with the suction water, the cooling water discharged from the return hole of the driving shaft is attached to the driving shaft along the flow direction of the suction water sucked from the suction port of the pump casing. A cooling water circulation type pump characterized in that a guide portion for changing to is provided.