JP6591601B2 - Submersible electric pump with oil return mechanism - Google Patents

Description

  The present invention relates to a submersible electric pump having an oil return mechanism.

  Conventionally, a small submersible electric pump including an oil chamber provided with a mechanical seal between the pump chamber and the motor chamber is known so that the pressure water in the pump chamber does not enter the motor chamber. However, this submersible electric pump has a disadvantage that pressure water, oil, or the like entering the oil chamber from the sliding portion may flow into the motor chamber due to wear or surface roughness of the sliding portion of the mechanical seal.

  Therefore, in order to prevent pressure water, oil, etc. from flowing into the motor chamber, a submersible pump that shuts off power to the motor by installing a submersion detection sensor in the oil chamber and detecting water intrusion into the oil chamber. Has been proposed (see, for example, Patent Document 1). In addition, a water immersion chamber is further provided between the oil chamber and the motor chamber to prevent the pressure water in the pump chamber and the oil in the oil chamber from entering the motor chamber, thereby detecting water intrusion in the water immersion chamber by the water immersion detector. Also, a submersible pump having a configuration that ensures a long time until the motor is deenergized has been proposed (see, for example, Patent Document 2).

JP 2002-310091 A JP 2007-332825 A

  However, in the submersible pump disclosed in Patent Document 1, when the pressure water in the pump chamber is submerged in the oil chamber by the submersion detection sensor, the pressure water, oil, or the like is prevented from flowing into the motor chamber. In order to suppress this, it is necessary to forcibly stop the submersible pump, pull it out of the water, remove the pump casing, the oil casing, etc., perform the maintenance work, and then restore it. In this case, in order to continue the operation, it is necessary to have a spare submersible pump and take emergency measures with the spare submersible pump. For this reason, there is a problem that a lot of labor is required for maintenance.

  Moreover, in the submersible pump of the above-mentioned Patent Document 2, since the water storage chamber is provided between the oil chamber and the motor chamber, it is possible to secure a long time until the motor is deenergized. The structure becomes complicated, and at the same time, the overall height of the pump is high and the size is increased. In addition, when the inundation detector detects inundation into the inundation reservoir chamber, the submersible pump is forcibly stopped and pulled up from the water in the same manner as the submersible pump of Patent Document 1 to perform maintenance work. Need to be restored. In this case, in order to continue the operation, an emergency response must be made with a spare submersible pump. For this reason, there is a problem that a lot of labor is required for maintenance.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a submersible electric pump having an oil return mechanism that can be easily maintained. is there.

  A submersible electric pump having an oil return mechanism according to one aspect of the present invention includes a motor chamber in which driving parts of a motor are incorporated, a pump chamber in which an impeller driven by the motor is disposed, and a mechanical seal having a sliding portion An annular space that is provided so as to surround the rotating shaft that communicates with the oil chamber disposed between the motor chamber and the pump chamber and the sliding portion of the mechanical seal and transmits the drive of the motor to the impeller. And a fluid return path that communicates the annular space chamber and the oil chamber.

  In the submersible electric pump having the oil return mechanism according to one aspect of the present invention, the above configuration allows the pressure water in the pump chamber to enter the oil chamber through the sliding portion of the mechanical seal. When fluid containing oil enters the annular space chamber from the oil chamber, the pressure in the annular space chamber is increased with the inflow of fluid. Then, when the pressure in the annular space exceeds the pressure in the oil chamber, the fluid flowing from the oil chamber into the annular space chamber is returned to the oil chamber through the fluid return path. Accordingly, it is possible to suppress additional water from the pump chamber to the oil chamber and to effectively suppress water from entering the motor chamber. Further, since the fluid containing the oil flowing out from the oil chamber is returned to the oil chamber through the fluid return path, it is not necessary to remove the pump casing, the oil casing, etc. and perform the maintenance work. Moreover, it is not necessary to have a spare submersible pump in order to continue operation. As a result, maintenance and management of the submersible electric pump can be easily performed without requiring much labor and cost for maintenance.

  The submersible electric pump having the oil return mechanism according to the one aspect preferably further includes a pump mechanism portion that is provided in the annular space chamber and sends fluid to the oil chamber side. With this configuration, the pressure in the annular space chamber can be forcibly increased, so that the oil rising from the sliding portion can be suppressed. As a result, oil leakage from the oil chamber can be effectively suppressed, and accordingly, water immersion from the pump chamber to the oil chamber can be suppressed to the minimum.

  In this case, preferably, the pump mechanism is disposed at least one of the outer peripheral portion of the rotating shaft and the position facing the outer peripheral portion of the rotating shaft. If comprised in this way, when a pump mechanism part is arrange | positioned in the outer peripheral part of the rotating shaft in an annular space chamber, an annular space chamber can be pressure | voltage-rised strongly. Further, when the pump mechanism portion is disposed at a position facing the outer peripheral portion of the rotating shaft, the pressure in the annular space chamber can be weakly increased. Further, when the pump mechanism portion is arranged at both the outer peripheral portion of the rotating shaft and the position facing the outer peripheral portion of the rotating shaft, the annular space chamber can be boosted efficiently and strongly. As a result, an appropriate pump mechanism can be selected and provided according to the submersion pressure from the pump chamber.

  The submersible electric pump having the oil return mechanism according to the one aspect preferably further includes a sealing member provided at the motor chamber side end of the annular space chamber and sealing the annular space chamber.

  In the submersible electric pump having the oil return mechanism according to the first aspect, the annular space chamber is preferably formed to extend from the oil chamber side toward the motor chamber side so as to surround the rotation shaft.

  The submersible electric pump having the oil return mechanism according to the one aspect preferably further includes a backflow prevention unit that is provided in the fluid return path and prevents the fluid from flowing back from the oil chamber. If comprised in this way, even when it stores with a submersible electric pump sideways, the leak by the backflow of the oil from an oil chamber can be prevented.

  The submersible electric pump having the oil return mechanism according to the one aspect preferably further includes a detection unit that is provided in the fluid return path and detects the return status of the fluid. If comprised in this way, it can be determined and monitored easily whether the return of fluid is functioning normally.

  ADVANTAGE OF THE INVENTION According to this invention, the submersible electric pump which has an oil return mechanism which can perform maintenance management easily as mentioned above can be provided.

It is the schematic which showed the submersible electric pump by 1st Embodiment of this invention. It is the schematic which showed the submersible electric pump by 2nd Embodiment of this invention. It is the schematic which showed the submersible electric pump by 3rd Embodiment of this invention. It is the schematic which showed the submersible electric pump by 4th Embodiment of this invention. It is the figure which showed the pump mechanism part of the submersible electric pump by 4th Embodiment of this invention. It is the schematic which showed the submersible electric pump by 5th Embodiment of this invention. It is the figure which showed the pump mechanism part of the submersible electric pump by 5th Embodiment of this invention.

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

(First embodiment)
A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the submersible electric pump 100 according to the first embodiment includes a motor 1, a motor chamber 1a, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a sliding portion. A mechanical seal 6 having 6a and 6b, an annular body 7, an annular space 8 and a fluid return path 9 are provided. The submersible electric pump 100 is an example of the “submersible electric pump having an oil return mechanism” in the present invention.

  Drive parts for the motor 1 are housed inside the motor chamber 1a. The driving parts of the motor 1 include a stator 11 and a rotor 12. The motor chamber 1a is sealed so that water from the outside does not enter. Further, the motor 1 is configured to rotationally drive the impeller 3 (rotating shaft 2).

  The stator 11 has a coil. Moreover, the stator 11 is arrange | positioned at the outer peripheral part in the motor chamber 1a. Further, the electric power supplied from the power cable 13 is configured to generate a magnetic field by supplying electric power to the coils of the stator 11. The rotor 12 is disposed inside the motor chamber 1 a so as to face the stator 11, and is provided on the outer periphery of the rotating shaft 2. The rotor 12 is configured to rotate by a magnetic field from the stator 11.

  The rotating shaft 2 is configured to rotate by driving the motor 1. The rotary shaft 2 is configured to transmit the drive of the motor 1 to the impeller 3. The rotating shaft 2 is rotatably supported by bearings 21 and 22. The bearing 21 is provided on the opposite side of the motor chamber 1a (the opposite side to the pump chamber 4). The bearing 22 is provided on the load side (pump chamber 4 side) of the motor chamber 1a. The rotating shaft 2 is disposed so as to extend from the motor chamber 1 a through the oil chamber 5 to the pump chamber 4. An impeller 3 is attached to the end of the rotary shaft 2 on the pump chamber 4 side.

  The impeller 3 is disposed in the pump chamber 4. Moreover, the impeller 3 gives speed energy to water by rotationally driving. And the speed energy of water is converted into pressure energy in the pump chamber 4, so that the pressure is applied to the water and sent. That is, by the rotational drive of the impeller 3, water is sucked up from the water suction port 41 of the pump chamber 4, and the water sucked up from the discharge port 42 is discharged.

  The oil chamber 5 is disposed between the motor chamber 1 a and the pump chamber 4. That is, the oil chamber 5 is provided in order to prevent the water in the pump chamber 4 from entering the motor chamber 1a. The oil chamber 5 is filled with oil. In the oil chamber 5, a mechanical seal 6 having sliding portions 6a and 6b is provided. Specifically, the sliding portion 6 a on the side opposite to the load side of the mechanical seal 6 (the side opposite to the pump chamber 4) is provided on the motor chamber 1 a side of the oil chamber 5. That is, the sliding portion 6a on the side opposite to the load side of the mechanical seal 6 (the side opposite to the pump chamber 4) is provided so that the fluid containing the oil in the oil chamber 5 does not enter the motor chamber 1a side. The sliding portion 6 b on the load side (pump chamber 4 side) of the mechanical seal 6 is provided on the pump chamber 4 side of the oil chamber 5. That is, the sliding portion 6 b on the load side (pump chamber 4 side) of the mechanical seal 6 is provided so that the pressure water in the pump chamber 4 does not enter the oil chamber 5.

  The mechanical seal 6 includes a fixed member 61, a rotating member 62, and a spring 63. The fixing member 61 is fixed to the housing of the oil chamber 5. The fixing member 61 is formed in an annular shape so as to surround the rotating shaft 2. The rotating member 62 is attached to the rotating 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 urged toward the fixed member 61 by a spring 63. The fixed member 61 and the rotating member 62 are disposed so as to face each other in the axial direction of the rotating shaft 2. Further, the fixed member 61 and the rotating member 62 have sliding surfaces 611 and 621, respectively. That is, in the sliding portions 6a and 6b, the sliding surface 611 of the fixing member 61 and the sliding surface 621 of the rotating member 62 are configured to slide relative to each other. Further, the oil in the oil chamber 5 slightly enters between the sliding surfaces 611 and 621. Thus, the sliding surfaces 611 and 621 are lubricated, and the sliding portions 6a and 6b (oil chamber 5) are sealed.

  The annular body 7 is provided so as to protrude from the wall 51 on the side opposite to the load of the oil chamber 5 (the side opposite to the pump chamber 4) toward the motor chamber 1a. The annular body 7 is provided in an annular shape so as to surround the rotation shaft 2 with a predetermined distance from the rotation shaft 2. A seal 71 is provided at the end of the annular body 7 on the motor chamber 1a side. As the seal 71, it is desirable to use, for example, an oil seal, a seal lip, or a seal having a mechanism for generating a thrust on the load side such as an inclined rib or a groove at a lip portion that slides with the rotary shaft 2. The seal 71 is disposed between the annular body 7 and the rotary shaft 2. The annular body 7 is provided with a hole 7a.

  The annular space 8 is surrounded by the annular body 7. The annular space portion 8 communicates with the sliding portion 6 a (sliding surfaces 611 and 621) of the mechanical seal 6 and is formed to extend toward the motor chamber 1 a so as to surround the rotating shaft 2. The annular space portion 8 is configured such that fluid including oil leaks from the sliding portion 6 a on the opposite side of the mechanical seal 6 (opposite side to the pump chamber 4). The end of the annular space 8 on the motor chamber 1a side is sealed with a seal 71. That is, the annular space portion 8 is a sealed space, and is configured such that the internal gas is compressed by the inflow of oil and the pressure rises.

  Here, in this embodiment, the fluid return path 9 is provided so as to communicate the annular space portion 8 and the oil chamber 5. Specifically, the fluid return path 9 includes a hole 51 a provided in the wall 51 on the side opposite to the load of the oil chamber 5 (the side opposite to the pump chamber 4), and a hole 7 a provided in the annular body 7. And are formed to be conductive. That is, the fluid return path 9 is configured to return the fluid containing the oil in the annular space 8 to the oil chamber 5. In addition, the fluid return path 9 is preferably configured by a pipe member such as a pipe or a tube, but may be configured such that an opening formed in an integral shape or a groove shape is sealed with a lid. In other words, the annular space 8 and the oil chamber 5 may be configured to communicate with each other.

  In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, it communicates with the sliding portion 6a on the anti-load side (opposite side to the pump chamber 4) of the mechanical seal 6 and faces the motor chamber 1a so as to surround the rotating shaft 2. The annular space 8 formed to extend, a seal 71 provided at the end of the annular space 8 on the side of the motor chamber 1a for sealing the annular space 8, and the annular space 8 and the oil chamber 5 communicate with each other. A fluid return path 9 is provided. Thereby, due to the pressure water in the pump chamber 4 entering the oil chamber 5 or the like, the oil chamber is passed through the sliding portion 6a on the side opposite to the load of the mechanical seal 6 (the side opposite to the pump chamber 4). When fluid containing oil enters the annular space 8 from 5, the pressure in the annular space 8 sealed by the seal 71 at the end of the motor chamber 1 a is increased as the fluid flows in. Then, when the pressure in the annular space portion 8 exceeds the pressure in the oil chamber 5, the fluid flowing into the annular space portion 8 from the oil chamber 5 is returned to the oil chamber 5 through the fluid return path 9. Accordingly, it is possible to suppress additional water immersion from the pump chamber 4 into the oil chamber 5 and to effectively suppress water immersion into the motor chamber 1a. Further, since the fluid containing the oil flowing out from the oil chamber 5 is returned to the oil chamber 5 through the fluid return path 9, there is no need to perform maintenance work by stopping the pump and removing the pump casing and the oil casing. Further, it is not necessary to have a spare submersible electric pump in order to continue operation. As a result, maintenance and management of the submersible electric pump 100 can be easily performed without requiring much labor and cost for maintenance.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, an example of a configuration in which a backflow prevention unit is further provided in the configuration of the first embodiment will be described.

  As shown in FIG. 2, the submersible electric pump 200 according to the second embodiment includes a motor 1, a motor chamber 1 a, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6. And an annular body 7, an annular space 8, and a fluid return path 9. The submersible electric pump 200 is an example of the “submersible electric pump having an oil return mechanism” in the present invention.

  Here, in the second embodiment, the fluid return path 9 is provided with a backflow prevention unit 91 that prevents the fluid from flowing back from the oil chamber 5. The backflow prevention unit 91 includes a check valve ball 911 and a stopper 912. That is, the backflow prevention unit 91 has a ball check mechanism. The check valve ball 911 is configured to open to allow fluid to pass through when the pressure in the annular space portion 8 becomes high with respect to the oil chamber 5. At that time, the check valve ball 911 is configured to come into contact with the stopper 912 and stop. The check valve ball 911 is configured to be pushed up and closed so as not to pass the fluid when the fluid flows backward from the oil chamber 5 through the fluid return path 9.

  The rest of the configuration of the second embodiment is the same as that of the first embodiment.

  In the second embodiment, the following effects can be obtained.

  In the second embodiment, as in the first embodiment, the annular space 8, the seal 71 that seals the annular space 8, the fluid return path 9 that communicates the annular space 8 and the oil chamber 5, and Is provided. Thereby, maintenance and management of the submersible electric pump 200 can be easily performed without requiring much labor and expense for maintenance.

  In the second embodiment, as described above, the backflow prevention unit 91 that is disposed in the fluid return path 9 and prevents the fluid from flowing back from the oil chamber 5 is provided. Thereby, even when the submersible electric pump 200 is laid down for a long time, for example, leakage due to the backflow of oil from the oil chamber 5 can be prevented.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, an example of a configuration in which a detection unit is further provided in the configuration of the second embodiment will be described.

  As shown in FIG. 3, the submersible electric pump 300 according to the third embodiment includes a motor 1, a motor chamber 1 a, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6. And an annular body 7, an annular space 8, a fluid return path 9, and a detector 10. The submersible electric pump 300 is an example of the “submersible electric pump having an oil return mechanism” in the present invention.

  Here, in the third embodiment, the fluid return path 9 is provided with a detection unit 10 that detects the fluid return status. The detection unit 10 is configured to detect, for example, the flow and speed of fluid and moisture in the fluid. That is, the detection unit 10 is provided to monitor whether or not the fluid return is functioning normally.

  In addition, the other structure of 3rd Embodiment is the same as that of the said 2nd Embodiment.

  In the third embodiment, the following effects can be obtained.

  In the third embodiment, similarly to the first embodiment, the annular space portion 8, the seal 71 that seals the annular space portion 8, the fluid return path 9 that communicates the annular space portion 8 and the oil chamber 5, and Is provided. Accordingly, maintenance and management of the submersible electric pump 300 can be easily performed without requiring much labor and cost for maintenance.

  In the third embodiment, as described above, the detection unit 10 that is disposed in the fluid return path 9 and detects the fluid return state is provided. Thereby, it is possible to easily determine and monitor whether or not the fluid return is functioning normally.

  The remaining effects of the third embodiment are similar to those of the aforementioned first and second embodiments.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. 4 and FIG. In the fourth embodiment, an example of a configuration in which a pump mechanism is further provided in the configuration of the third embodiment will be described.

  As shown in FIG. 4, the submersible electric pump 400 according to the fourth embodiment includes a motor 1, a motor chamber 1 a, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6. And an annular body 7, an annular space 8, a fluid return path 9, and a detector 10. The submersible electric pump 400 is an example of the “submersible electric pump having an oil return mechanism” in the present invention.

  Here, in the fourth embodiment, the annular space portion 8 is provided with a pump mechanism portion 81 that sends fluid to the sliding portion 6a side of the mechanical seal 6 on the side opposite to the load (the side opposite to the pump chamber 4). ing. The pump mechanism part 81 is arrange | positioned at the outer peripheral part of the rotating shaft 2, as shown in FIG. The pump mechanism 81 has a spiral groove 811. As a result, when the pump mechanism 81 rotates together with the rotary shaft 2, the fluid in the annular space 8 is sent along the spiral groove 811 to the oil chamber 5 side.

  In addition, the other structure of 4th Embodiment is the same as that of the said 3rd Embodiment.

  In the fourth embodiment, the following effects can be obtained.

  In the fourth embodiment, as in the first embodiment, the annular space portion 8, the seal 71 that seals the annular space portion 8, the fluid return path 9 that communicates the annular space portion 8 and the oil chamber 5, and Is provided. Accordingly, maintenance and management of the submersible electric pump 400 can be easily performed without requiring much labor and cost for maintenance.

  In the fourth embodiment, as described above, the pump mechanism is arranged in the annular space portion 8 and sends the fluid to the sliding portion 6a side of the mechanical seal 6 on the side opposite to the load (the side opposite to the pump chamber 4). A portion 81 is provided. Thereby, since the pressure in the annular space part 8 can be forcedly raised, oil rising from the sliding part 6a can be suppressed. As a result, the leakage of oil from the oil chamber 5 can be effectively suppressed, so that the water intrusion from the pump chamber 4 into the oil chamber 5 can be suppressed to the minimum.

  In the fourth embodiment, as described above, the pump mechanism portion 81 is disposed on the outer peripheral portion of the rotating shaft 2 in the annular space portion 8. As a result, the annular space 8 can be strongly boosted.

  The remaining effects of the fourth embodiment are similar to those of the aforementioned first to third embodiments.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, an example of a configuration in which a pump mechanism 82 is further provided in the configuration of the third embodiment will be described.

  As shown in FIG. 6, the submersible electric pump 500 according to the fifth embodiment includes a motor 1, a motor chamber 1 a, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6. And an annular body 7, an annular space 8, a fluid return path 9, and a detector 10. The submersible electric pump 500 is an example of the “submersible electric pump having an oil return mechanism” in the present invention.

  Here, in the fifth embodiment, the annular space portion 8 is provided with a pump mechanism portion 82 that sends fluid to the sliding portion 6a side on the side opposite to the load side of the mechanical seal 6 (opposite side to the pump chamber 4). ing. As shown in FIG. 7, the pump mechanism portion 82 is disposed at a position facing the outer peripheral portion of the rotating shaft 2. That is, the pump mechanism portion 82 is provided on the inner peripheral portion of the annular body 7. The pump mechanism 82 has a spiral groove 821. Thereby, when the fluid around the rotating shaft 2 is rotated by the rotation of the rotating shaft 2, the fluid is sent along the spiral groove 821 to the oil chamber 5 side.

  The remaining configuration of the fifth embodiment is similar to that of the aforementioned third embodiment.

  In the fifth embodiment, the following effects can be obtained.

  In the fifth embodiment, similar to the first embodiment, the annular space portion 8, the seal 71 that seals the annular space portion 8, and the fluid return path 9 that communicates the annular space portion 8 and the oil chamber 5. Is provided. Thereby, maintenance and management of the submersible electric pump 500 can be easily performed without requiring much labor and cost for maintenance.

  In the fifth embodiment, as described above, the pump mechanism is arranged in the annular space portion 8 and sends the fluid to the sliding portion 6a side of the mechanical seal 6 on the side opposite to the load (the side opposite to the pump chamber 4). A portion 82 is provided. Thereby, since the pressure in the annular space part 8 can be forcedly raised, oil rising from the sliding part 6a can be suppressed. As a result, the leakage of oil from the oil chamber 5 can be effectively suppressed, so that the water intrusion from the pump chamber 4 into the oil chamber 5 can be suppressed to the minimum.

  In the fifth embodiment, as described above, the pump mechanism 82 is disposed at a position facing the outer peripheral portion of the rotating shaft 2. Thereby, the annular space 8 can be boosted weakly.

  The remaining effects of the fifth embodiment are similar to those of the aforementioned first to third embodiments.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims, and further includes meanings equivalent to the scope of claims and all modifications (variants) within the scope.

  For example, in the first to fifth embodiments, the example in which the present invention is applied to the vertical submersible electric pump arranged so that the rotation axis extends in the vertical direction is shown, but the present invention is not limited to this. You may apply this invention to the horizontal submersible electric pump arrange | positioned so that a rotating shaft may extend in a horizontal direction.

  Moreover, in the said 1st-5th embodiment, although the fluid return path showed the example comprised by pipe members, such as a pipe and a tube, this invention is not limited to this. In the present invention, the fluid return path may be provided by forming a groove in a housing or the like and capping the groove. Further, a fluid return path may be formed by digging a channel in the housing.

  Moreover, in the said 4th Embodiment, the pump mechanism part is arrange | positioned at the outer peripheral part of a rotating shaft, and in the said 5th Embodiment, the example of the structure by which the pump mechanism part is arrange | positioned in the position facing the outer peripheral part of a rotating shaft. However, the present invention is not limited to this. In this invention, you may arrange | position a pump mechanism part in both the outer peripheral part of a rotating shaft, and the position facing the outer peripheral part of a rotating shaft.

  Moreover, in the said 4th and 5th embodiment, although the example of the structure by which the spiral groove was provided in the pump mechanism part was shown, this invention is not limited to this. In the present invention, a wing-shaped blade or a centrifugal blade may be provided in the pump mechanism portion so as to send (pressurize) the fluid in the annular space portion.

  Moreover, although the said 1st-5th embodiment showed the example of the structure by which the mechanical seal which has the two sliding parts 6a and 6b was provided in the oil chamber, this invention is not limited to this. In the present invention, a mechanical seal of one sliding portion 6b may be provided in the oil chamber, or a mechanical seal having three or more sliding portions may be provided.

DESCRIPTION OF SYMBOLS 1 Motor 1a Motor chamber 2 Rotating shaft 3 Impeller 4 Pump chamber 5 Oil chamber 6 Mechanical seal 6a, 6b Sliding part 8 Annular space part 9 Fluid return path 10 Detection part 11 Stator (drive component)
12 Rotor (drive parts)
71 Seal 81, 82 Pump mechanism 91 Backflow prevention unit 100, 200, 300, 400, 500 Submersible electric pump (submersible electric pump having an oil return mechanism)

Claims (7)

A motor room in which motor drive parts are installed;
A pump chamber in which an impeller driven by the motor is disposed;
An oil chamber provided with a mechanical seal having a sliding portion, and disposed between the motor chamber and the pump chamber;
An annular space chamber formed to surround a rotating shaft that communicates with the sliding portion of the mechanical seal and transmits the drive of the motor to the impeller;
A submersible electric pump having an oil return mechanism, comprising a fluid return path communicating the annular space chamber and the oil chamber.   The submersible electric pump having an oil return mechanism according to claim 1, further comprising a pump mechanism section that is provided in the annular space chamber and sends a fluid to the oil chamber side.   3. The submersible electric pump having an oil return mechanism according to claim 2, wherein the pump mechanism is disposed at least one of an outer peripheral portion of the rotating shaft and a position facing the outer peripheral portion of the rotating shaft.   The submersible electric pump having an oil return mechanism according to any one of claims 1 to 3, further comprising a sealing member that is provided at an end of the annular space chamber on the motor chamber side and seals the annular space chamber.   5. The oil return mechanism according to claim 1, wherein the annular space chamber is formed to extend from the oil chamber side toward the motor chamber side so as to surround the rotation shaft. Submersible electric pump.   The submersible electric pump having an oil return mechanism according to any one of claims 1 to 5, further comprising a backflow prevention unit that is provided in the fluid return path and prevents backflow of fluid from the oil chamber.   The submersible electric pump having an oil return mechanism according to any one of claims 1 to 6, further comprising a detection unit that is provided in the fluid return path and detects a fluid return state.

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