JP2020128714A - Submerged pump - Google Patents

Abstract

To provide a submerged pump capable of preventing infiltration of water from a pump chamber to an oil chamber.SOLUTION: A submerged pump 100 comprises: a motor 1; a suction port 7 to suck liquid into a pump chamber 3; a base section 41 which is installed on a rotary shaft 2 rotary driven by the motor 1; an impeller 4 which is installed in the pump chamber 3 and includes a blade section 42 arranged on the base section 41 at the side of the suction port 7 in a shaft direction of the rotary shaft 2; and a mechanical seal 6 which is installed in an oil chamber 5 between the pump chamber 3 and motor 1 and includes sliding sections 6a and 6b sliding along with rotation of the rotary shaft 2. The suction port 7 is configured to allow the fluid to flow into the pump chamber 3 in a direction perpendicular to the shaft direction and arranged at a position closer to the mechanical seal 6 than to the impeller 4 in the shaft direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a submersible pump.

Conventionally, a submersible pump including a mechanical seal has been known (for example, refer to Patent Document 1).

In Patent Document 1, a motor for rotating an impeller arranged in a pump chamber via a rotary shaft, a mechanical seal arranged in an oil chamber between the pump chamber, and a liquid flowing into the pump chamber are disclosed. A submersible pump having a suction port for allowing the submersible pump is disclosed. The suction port is arranged immediately below the impeller (on the side opposite to the motor side of the impeller in the axial direction of the rotating shaft). The submersible pump makes the suction port side of the impeller a negative pressure by rotating the impeller in order to allow the liquid to flow from the suction port, and the side opposite to the suction port side of the impeller (mechanical seal side). Is configured to be in a pressurized state (positive pressure).

JP 2002-310091 A

However, in the submersible pump of Patent Document 1 described above, the side (mechanical seal side) opposite to the suction port side of the impeller is in a pressurized state (positive pressure), so that the pump chamber side is changed to the oil chamber side. There is a problem that water pressure from the pump chamber to the oil chamber is likely to occur due to the pressure applied to the sliding portion of the mechanical seal in the direction.

The present invention has been made to solve the above problems, and one object of the present invention is to provide a submersible pump capable of suppressing water infiltration from a pump chamber to an oil chamber. is there.

A submersible pump according to one aspect of the present invention includes a motor, a suction port that allows liquid to flow into a pump chamber, a base portion that is attached to a rotary shaft that is rotationally driven by the motor, and a suction port of the base portion in the axial direction of the rotary shaft. A blade part provided on the side of the pump chamber, and an impeller arranged in the pump chamber, and a sliding part that slides with the rotation of the rotating shaft, and is arranged in the oil chamber between the pump chamber and the motor. And a mechanical seal, and the suction port is configured to allow the liquid to flow into the pump chamber from a direction intersecting the axial direction, and is arranged at a position closer to the mechanical seal than the impeller in the axial direction. ..

In the submersible pump according to one aspect of the present invention, by configuring as described above, the liquid is caused to flow into the pump chamber from the suction port between the mechanical seal and the impeller in the axial direction of the rotating shaft, and the impeller is also provided. This allows the liquid to flow in the direction away from the mechanical seal. That is, contrary to the conventional case where the suction port is arranged directly below the impeller, the mechanical seal side of the impeller is used as a negative pressure to flow the liquid to the impeller side, and the mechanical seal side of the impeller is Can set the opposite side to a pressurized state (positive pressure). Accordingly, it is possible to suppress the pressure from being pushed to the sliding portion of the mechanical seal in the direction from the pump chamber side to the oil chamber side, and thus it is possible to suppress the water from the pump chamber to the oil chamber. .. In the axial direction, since the suction port is located closer to the mechanical seal than the impeller, the mechanical seal can be further separated from the pressurized region of the pump chamber, effectively, It is possible to prevent water from entering the oil chamber from the pump chamber.

In the submersible pump according to the above aspect, preferably, a portion of the pump chamber on the oil chamber side is configured to have a negative pressure due to rotation of the impeller. According to this structure, it is possible to suppress the negative pressure generated by the rotation of the impeller from being applied from the pump chamber side to the oil chamber side so as to push the sliding portion of the mechanical seal. Therefore, it is possible to prevent water from entering the oil chamber from the pump chamber.

The submersible pump according to the above aspect preferably further includes a discharge port through which the liquid flows out from the pump chamber, and the suction port is arranged at a position that does not overlap the discharge port in the axial direction. According to this structure, as compared with the case where the suction port overlaps with the discharge port in the axial direction, the liquid flowing from the suction port is separated from the mechanical seal (axial direction toward the impeller). ) Can be effectively generated. That is, it is possible to generate the region in the pressurized state at a position further away from the mechanical seal. As a result, it is possible to more effectively prevent water from entering the oil chamber from the pump chamber.

In this case, preferably, the suction port is arranged at a position closer to the mechanical seal than the discharge port in the axial direction. According to this structure, the region to be pressurized can be generated at a position further apart from the mechanical seal, so that the water from the pump chamber to the oil chamber can be further suppressed.

In the submersible pump according to the above aspect, the opening area of the suction port is preferably larger than the area of the cross section of the rotating shaft orthogonal to the axial direction. According to this structure, since a relatively large opening area of the suction port can be secured, the liquid can effectively flow into the pump chamber.

In the submersible pump according to the above aspect, the opening area of the suction port is preferably substantially the same as the area of the inner region of the inner diameter of the end portion of the blade portion on the suction port side. According to this structure, the amount of liquid suitable for the specifications of the impeller can be made to flow from the suction port.

The submersible pump according to the above aspect preferably further includes a discharge port through which the liquid flows out from the pump chamber, and the suction port and the discharge port are arranged on one side and the other side of the rotary shaft, respectively. According to this structure, compared with the case where the suction port and the discharge port are arranged on the same side of the rotation shaft, the liquid that flows in the order of the suction port, the impeller, and the discharge port when viewed in the axial direction of the rotation shaft. It is possible to prevent the orientation of the object from changing significantly. That is, the liquid can efficiently flow in the pump chamber.

According to the present invention, as described above, it is possible to provide the submersible pump capable of suppressing the infiltration of water from the pump chamber into the oil chamber.

It is a typical side view showing the section shape of the submersible pump by one embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment]
(Constitution of submersible pump)
An underwater pump 100 according to an embodiment of the present invention will be described with reference to FIG. 1.

As shown in FIG. 1, the submersible pump 100 includes a motor 1, a rotary shaft 2, a pump chamber 3, an impeller 4, an oil chamber 5, and a mechanical seal 6. Further, the submersible pump 100 includes a suction port 7 that allows the liquid to flow into the pump chamber 3, and a discharge port 8 that causes the liquid to flow from the pump chamber 3. The submersible pump 100 is a vertical submersible pump in which the rotating shaft 2 extends in the vertical direction.

In each drawing, the axial direction of the rotary shaft 2, that is, the vertical direction is shown as the Z direction. Further, in the Z direction, the upper side is shown as the Z1 direction and the lower side is shown as the Z2 direction.

The motor 1 is hermetically sealed so that water from the outside does not enter. Further, the motor 1 is configured to rotationally drive the impeller 4 connected to the rotary shaft 2 via the rotary shaft 2. Specifically, the motor 1 includes a stator 11 and a rotor 12. The stator 11 is arranged on the outer side (outer peripheral side) of the rotor 12. The stator 11 has a coil (not shown). Further, the stator 11 is configured to generate a magnetic field when power is supplied from the cable C. The rotor 12 is attached to the rotating shaft 2 and is arranged inside (inner peripheral side) of the stator 11 so as to face the stator 11. That is, the motor 1 is an inner rotor motor. Further, the rotor 12 is configured to rotate together with the rotating shaft 2 by the magnetic field from the stator 11. The rotor 12 is configured to drive the impeller 4 to rotate via the rotary shaft 2.

The rotary shaft 2 is configured to rotate by driving the motor 1. Further, the rotary shaft 2 is configured to transmit the driving force (torque) of the motor 1 to the impeller 4. The rotating shaft 2 is rotatably supported by bearings 21 and 22. The rotary shaft 2 is arranged so as to extend from the motor 1 through the oil chamber 5 to the pump chamber 3. Further, an impeller 4 is attached to an end portion (Z2 direction side end portion) opposite to the motor 1 side end portion (Z1 direction side end portion) of the rotary shaft 2.

An impeller 4 is arranged in the pump chamber 3. The pump chamber 3 is configured such that the liquid flows from the suction port 7 and the liquid flows from the discharge port 8 as the impeller 4 is rotationally driven.

The impeller 4 is attached to a rotary shaft 2 that is driven to rotate by a motor 1. The impeller 4 includes a base portion 41 and a blade portion 42.

The base portion 41 is attached to the rotating shaft 2 and is configured to rotate together with the rotating shaft 2. The base 41 has a disc shape extending in a direction orthogonal to the axial direction (Z direction) of the rotating shaft 2. The blade portion 42 is provided on the suction port 7 side (Z1 direction side) of the base portion 41 in the axial direction (Z direction) of the rotating shaft 2. The blade portion 42 is composed of a single blade or a plurality of blades.

The impeller 4 is configured to generate a negative pressure near the suction port 7 side (Z1 direction side) of the impeller 4 in the axial direction (Z direction) of the rotating shaft 2 by being rotationally driven. .. At the same time, the impeller 4 is configured to generate a positive pressure in the axial direction (Z direction) of the rotating shaft 2 near the suction port 7 side of the impeller 4 (Z2 direction side). .. That is, the impeller 4 is configured such that, in the axial direction (Z direction) of the rotating shaft 2, the vicinity of the side (Z2 direction side) opposite to the suction port 7 side of the impeller 4 is in a pressurized state. .. As a result, the impeller 4 draws in the fluid flowing from the suction port 7 and generates a flow toward the discharge port 8. Therefore, the portion of the pump chamber 3 on the oil chamber 5 side is configured to have a negative pressure due to the rotation of the impeller 4.

The negative pressure and the positive pressure mean that they are a negative pressure and a positive pressure, respectively, with a static water pressure at a water depth substantially equal to that of the impeller 4 as a reference water pressure. Further, in the axial direction (Z direction) of the rotary shaft 2, the suction port 7 side (Z1 direction side) of the impeller 4 is the oil chamber 5 side (mechanical seal 6 side) of the impeller 4.

The oil chamber 5 is arranged between the pump chamber 3 and the motor 1. The oil chamber 5 is filled with oil. A mechanical seal 6 is arranged in the oil chamber 5.

The mechanical seal 6 includes sliding portions 6 a and 6 b that slide with the rotation of the rotating shaft 2, a fixed member 61, a rotating member 62, and a spring 63.

The sliding portion 6a is provided on the counter load side of the mechanical seal 6, that is, on the motor 1 side (upper side) of the oil chamber 5. Therefore, the sliding portion 6a suppresses the oil in the oil chamber 5 from flowing into the motor 1 (motor chamber) side.

The sliding portion 6b is provided on the load side of the mechanical seal 6, that is, on the pump chamber 3 side (Z2 direction side) of the oil chamber 5. Therefore, the sliding portion 6b suppresses the liquid in the pump chamber 3 from flowing into the oil chamber 5.

The fixing member 61 is fixed to the inner wall of the oil chamber 5. Further, the fixing member 61 is formed in an annular shape so as to surround the rotating shaft 2. The rotary member 62 is attached to the rotary shaft 2. That is, the rotating member 62 is configured to rotate together with the rotating shaft 2. The rotating member 62 is formed in an annular shape so as to surround the rotating shaft 2. The rotating member 62 is biased toward the fixed member 61 by a spring 63. The fixed member 61 and the rotating member 62 are arranged so as to face each other in the axial direction of the rotating shaft 2.

The fixed member 61 and the rotating member 62 have sliding surfaces 611 and 621 between the fixed member 61 and the rotating member 62, respectively. That is, in the sliding portions 6a and 6b, the sliding surface 611 of the fixed member 61 and the sliding surface 621 of the rotating member 62 are configured to slide with each other. Further, a small amount of oil in the oil chamber 5 enters between the sliding surfaces 611 and 621. As a result, the sliding surfaces 611 and 621 are lubricated and the sliding portions 6a and 6b (oil chamber 5) are sealed.

The suction port 7 (suction flow path) is configured to allow the liquid to flow into the pump chamber 3 from a direction intersecting the axial direction (Z direction) of the rotating shaft 2. The suction port 7 is arranged at a position closer to the mechanical seal 6 than the impeller 4 (position on the Z1 direction side) in the axial direction of the rotating shaft 2 (Z direction). That is, in the axial direction (Z direction) of the rotary shaft 2, the distance D1 between the upper end of the suction port 7 and the lower end of the mechanical seal 6 is equal to the lower end of the suction port 7 and the upper end of the impeller 4 (the blade portion 42 described later). Is smaller than the distance D2 from the end 42a).

Further, the suction port 7 is arranged at a position that does not overlap the discharge port 8 in the axial direction (Z direction) of the rotating shaft 2. Further, the suction port 7 is arranged at a position closer to the mechanical seal 6 than the discharge port 8 (a position on the Z1 direction side) in the axial direction of the rotating shaft 2 (Z direction).

The flow path cross section of the suction port 7 (the broken line portion in FIG. 1) is formed in a circular shape. The opening area S1 of the suction port 7 is larger than the area S2 of the cross section of the rotary shaft 2 orthogonal to the axial direction (Z direction) of the rotary shaft 2. The opening area S1 of the suction port 7 has substantially the same size as the opening area of the discharge port 8. Further, the opening area S1 of the suction port 7 is substantially the same as the area S3 of the inner region of the inner diameter (the liquid suction port of the impeller 4) at the end 42a of the blade portion 42 on the suction port 7 side (Z1 direction side). It's size.

The suction port 7 and the discharge port 8 are arranged on one side and the other side of the rotary shaft 2, respectively. That is, the suction port 7 and the discharge port 8 are arranged so as to sandwich the rotating shaft 2, and the center line (not shown) of the suction port 7 and the discharge port 8 in a plan view (viewed from the Z direction). Are arranged on substantially the same straight line.

The submersible pump 100 is provided with a rib portion 9 extending along the suction port 7 so as to project inward from the inner surface of the casing forming the pump chamber 3 on the impeller 4 side of the suction port 7. There is. The rib portion 9 guides the liquid flowing from the suction port 7 to the vicinity of the rotating shaft 2 before reaching the vicinity of the impeller 4. The rib portion 9 causes the submersible pump 100 to generate a flow of liquid in the pump chamber 3 from almost directly above the impeller 4 (Z1 direction side) toward the impeller 4.

(Effects of the embodiment)
In this embodiment, the following effects can be obtained.

In the present embodiment, as described above, in the axial direction of the rotary shaft 2, the liquid is caused to flow into the pump chamber 3 from the suction port 7 between the mechanical seal 6 and the impeller 4, and the mechanical seal 6 is made by the impeller 4. Liquid can flow away from. That is, contrary to the conventional case where the suction port 7 is arranged directly below the impeller 4, the liquid is caused to flow to the impeller 4 side while the mechanical seal 6 side of the impeller 4 is used as a negative pressure, and The side opposite to the mechanical seal 6 side of 4 can be in a pressurized state (positive pressure). As a result, it is possible to prevent pressure from being applied to the sliding portion 6b of the mechanical seal 6 in the direction from the pump chamber 3 side to the oil chamber 5 side. Can be suppressed. Since the suction port 7 is located closer to the mechanical seal 6 than the impeller 4 in the axial direction, the mechanical seal 6 can be further separated from the region of the pump chamber 3 in the pressurized state. Thus, it is possible to effectively prevent the water from entering the oil chamber 5 from the pump chamber 3.

In the present embodiment, as described above, the portion of the pump chamber 3 on the oil chamber side is configured to have a negative pressure due to the rotation of the impeller 4. As a result, it is possible to prevent the negative pressure generated by the rotation of the impeller 4 from applying a pressure that pushes the sliding portion 6b of the mechanical seal 6 in the direction from the pump chamber 3 side to the oil chamber 5 side. .. For this reason, it is possible to suppress water from entering the oil chamber 5 from the pump chamber 3.

In the present embodiment, as described above, the discharge port 8 that causes the liquid to flow out from the pump chamber 3 is further provided, and the suction port 7 is arranged at a position that does not overlap the discharge port 8 in the axial direction. As a result, as compared with the case where the suction port 7 overlaps the discharge port 8 in the axial direction, the liquid flowing from the suction port 7 is separated from the mechanical seal 6 (the axis toward the impeller 4). Flow) can be effectively generated. That is, it is possible to generate a region in a pressurized state at a position further away from the mechanical seal 6. As a result, it is possible to more effectively suppress water from entering the oil chamber 5 from the pump chamber 3.

In the present embodiment, as described above, the suction port 7 is arranged closer to the mechanical seal 6 than the discharge port 8 in the axial direction. As a result, a region to be pressurized can be generated at a position further apart from the mechanical seal 6, so that water infiltration from the pump chamber 3 into the oil chamber 5 can be further suppressed.

In the present embodiment, as described above, the opening area of the suction port 7 is larger than the area of the cross section of the rotary shaft 2 orthogonal to the axial direction. As a result, a relatively large opening area of the suction port 7 can be secured, so that the liquid can effectively flow into the pump chamber 3.

In the present embodiment, as described above, the opening area of the suction port 7 is substantially the same as the area of the inner region of the inner diameter of the end portion 42a of the blade portion 42 on the suction port 7 side. Thereby, the amount of liquid suitable for the specifications of the impeller 4 can be introduced from the suction port 7.

In the present embodiment, as described above, the discharge port 8 for causing the liquid to flow out from the pump chamber 3 is further provided, and the suction port 7 and the discharge port 8 are arranged on one side and the other side of the rotary shaft 2, respectively. .. Thereby, as compared with the case where the suction port 7 and the discharge port 8 are arranged on the same side of the rotary shaft 2, the suction port 7, the impeller 4, and the discharge port 8 are viewed from the axial direction of the rotary shaft 2. It is possible to suppress a large change in the direction of the liquid flowing in order. That is, the liquid can efficiently flow in the pump chamber 3.

(Modification)
It should be understood that the embodiments disclosed this time are exemplifications in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications (modifications) within the scope.

For example, in the above-described embodiment, an example in which the shape of the suction port is circular is shown, but the present invention is not limited to this. In the present invention, the shape of the suction port may be a shape other than a circular shape such as a rectangular shape.

Further, in the above-described embodiment, the example in which the discharge port and the suction port do not overlap each other in the axial direction of the rotating shaft has been shown, but the present invention is not limited to this. In the present invention, the discharge port and the suction port may overlap each other.

Further, in the above-described embodiment, an example is shown in which the center lines (not shown) of the suction port and the discharge port are arranged on substantially the same straight line in a plan view (viewed from the Z direction). Is not limited to this. In the present invention, they may be arranged on different straight lines (when viewed from the Z direction) in plan view. Therefore, for example, in plan view (as viewed from the Z direction), the suction port and the discharge port may be arranged so as to overlap with each other.

Further, the opening area of the suction port is not limited to that described in the above embodiment.

Further, in the above-described embodiment, the example in which the present invention is applied to the vertical submersible pump in which the rotary shaft is arranged to extend in the vertical direction has been shown, but the present invention is not limited to this. The present invention may be applied to a horizontal submersible electric pump in which a rotary shaft is arranged so as to extend in the horizontal direction. At this time, the suction port is preferably arranged on the lower side.

1 Motor 2 Rotating Shaft 3 Pump Chamber 4 Impeller 5 Oil Chamber 6 Mechanical Seals 6a, 6b Sliding Part 7 Suction Port 8 Discharge Port 41 Base 42 Blade 42a (Suction Port Side of Blade) 100 Submersible Pump

Claims (7)

A motor,
A suction port that allows liquid to flow into the pump chamber,
An impeller disposed in the pump chamber, including a base portion attached to a rotary shaft that is rotationally driven by the motor, and a blade portion provided on the suction port side of the base portion in the axial direction of the rotary shaft. ,
A mechanical seal disposed in an oil chamber between the pump chamber and the motor, including a sliding portion that slides with the rotation of the rotating shaft;
The suction port is configured to allow liquid to flow into the pump chamber from a direction intersecting the axial direction, and is arranged at a position closer to the mechanical seal than the impeller in the axial direction. underwater pump. The submersible pump according to claim 1, wherein a portion of the pump chamber on the oil chamber side is configured to have a negative pressure due to rotation of the impeller. Further comprising a discharge port for discharging the liquid from the pump chamber,
The submersible pump according to claim 1, wherein the suction port is arranged at a position that does not overlap the discharge port in the axial direction. The submersible pump according to claim 3, wherein the suction port is arranged at a position closer to the mechanical seal than the discharge port in the axial direction. The submersible pump according to any one of claims 1 to 4, wherein an opening area of the suction port is larger than an area of a cross section of the rotary shaft orthogonal to the axial direction. The submersible pump according to any one of claims 1 to 5, wherein the opening area of the suction port is substantially the same as the area of the inner region of the inner diameter of the end portion of the blade portion on the suction port side. Further comprising a discharge port for discharging the liquid from the pump chamber,
The submersible pump according to any one of claims 1 to 6, wherein the suction port and the discharge port are arranged on one side and the other side of the rotary shaft, respectively.

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