JP6614484B2 - Electric submersible pump and electric submersible pump system including the same - Google Patents

Description

  The present invention relates to an electric liquid submersible pump in which at least a part is disposed in a liquid, and an electric liquid submersible pump system including the same.

  As an electric liquid submersible pump, there exist some which are indicated in the following patent documents 1, for example. This electric submersible pump includes a submersible pump arranged in water, a motor arranged in water and driving the submersible pump, and an inverter attached to a casing of the submersible pump.

JP 2002-223574 A

  Electric submersible pumps are sometimes used to pump liquids such as oil and hot water that are buried deep underground. Such an electric liquid submersible pump is often arranged at a position several thousand meters underground. In this case, the length of the power transmission cable that sends power to the submerged pump becomes several thousand meters, and the power loss in the power transmission cable increases.

  Therefore, an object of the present invention is to provide an electro-hydraulic pump that can suppress power loss, and an electro-hydraulic pump system including the same.

The motor-driven liquid pump as one aspect according to the invention for achieving the above object is
At least a portion is placed in a liquid, and a pump in the liquid for pumping the liquid, and a motor for driving the liquid pump is disposed in the liquid, and the step-down unit, a pressure equalizing seal mechanism, Ru comprising a. The step-down device lowers the voltage of the AC power from the outside to a voltage suitable for driving the motor and supplies the motor with the reduced AC power. The step-down circuit is attached to the motor casing of the motor. to have a, a voltage reducer casing cover. The motor includes a stator, a motor rotating shaft, a rotor attached to the motor rotating shaft and rotating relative to the stator integrally with the motor rotating shaft, and the motor casing covering the stator and the rotor. Have. The motor rotation shaft has a first end and a second end, and the first end protrudes from the motor casing. The submerged pump has a pump rotation shaft connected to the motor rotation shaft. The pressure equalizing seal mechanism is attached to the motor casing and covers a part of the first end portion of the motor rotating shaft, and a meandering flow path meandering in the seal casing together with the seal casing And a flow path forming member for forming The meandering channel includes a liquid inlet for introducing the liquid into the interior thereof, a communication port communicating with the inside of the motor casing, a liquid flowing in from the liquid inlet, one of the inside of the motor casing and the meandering channel. And a liquid contact portion for contacting the insulating oil filled in the portion.

  The electric liquid submersible pump may be installed at a position of about 1000 m underground, or sometimes installed at a position of 3000 m or more underground. For this reason, the cable which sends electric power to the motor of the pump for electric liquid is also a long cable of 1000 m or more. Thus, when the length of the cable is increased, the power loss in the cable cannot be ignored. Since the submerged pump has a step-down device, high-voltage AC power can flow through the cable. The power loss of a cable is proportional to the square of the value of the current flowing through this cable. For this reason, in the said electrohydraulic pump, by increasing the voltage value of the power flowing through the cable, the current value of this power is decreased and the power loss in the cable can be suppressed.

  Further, in the submerged pump, since high-voltage AC power can flow through the cable, the outer diameter of the conductor forming the cable can be reduced, and thus the outer diameter of the cable can also be reduced. . For this reason, in the said motor submersible pump, the manufacture (or purchase) cost of a cable can be held down. Furthermore, since the electric liquid pump can reduce the total weight of the cable, the installation cost of the cable can be reduced.

  An external liquid flows into the seal casing from the liquid inlet. For this reason, the pressure inside this seal casing becomes the same as the pressure outside the seal casing. In addition, since the inside of the seal casing and the inside of the motor casing communicate with each other through the communication port, the pressure inside the motor casing becomes the same as the pressure inside the seal casing, and as a result, the pressure outside the seal casing and outside the motor casing. Will be the same. Therefore, even when the depth of the electric liquid pump is deepened and the pressure of the liquid at the position where the electric liquid pump is installed increases, pressure equalization can be achieved between the motor casing and the outside of the motor casing. It is done. For this reason, in the said motor submerged pump, the motor damage by external pressure can be prevented irrespective of the installation depth of a motor submerged pump.

  Further, in the electric liquid submersible pump including the pressure equalizing seal mechanism, a communication hole is formed at the boundary between the motor casing and the step-down casing to connect the motor casing and the step-down casing. May be.

  In the electric liquid submersible pump, a communication hole is formed to allow communication between the motor casing and the step-down casing. For this reason, in the electric liquid submersible pump, the pressure in the step-down casing is the same as the pressure in the motor casing, and as a result, the pressure is the same as the pressure outside the motor casing and outside the step-down casing. Therefore, in the electric submerged pump, the depth of the electric submerged pump is deepened, and even when the pressure of the liquid at the position where the electric submerged pump is increased, damage to the step-down device due to external pressure is prevented. Can do.

  Further, in any one of the above-described submersible pumps having the motor rotation shaft, the second end portion of the motor rotation shaft protrudes from the motor casing and enters the step-down casing. You may have a stirring blade attached to a 2nd end part and stirring or circulating the insulating oil with which the said pressure | voltage fall casing is satisfy | filled.

  In the electric submerged pump, the motor rotating shaft rotates, so that the insulating oil filled in the step-down casing can be stirred or circulated by the stirring blades in the step-down casing. Therefore, in the submerged pump, the cooling of the step-down circuit in the step-down casing can be promoted.

An electro-hydraulic pump as another aspect according to the invention for achieving the above object is as follows:
At least a part is disposed in the liquid, and includes a submerged pump that pumps up the liquid, a motor that is disposed in the liquid and drives the submerged pump, a step-down device, and an insulating oil pump. The step-down device includes a step-down circuit that lowers the voltage of AC power from the outside to a voltage suitable for driving the motor and supplies AC power that has been dropped to the motor, and a step-down circuit that is attached to a motor casing of the motor. And a step-down casing for covering. The insulating oil pump is disposed in the step-down device casing, by discharging inhale insulating oil filled in the step-down unit casing, Ru is to or circulated stirred insulating oil filled in the step-down unit casing .

  In the electric submersible pump, the insulating oil filled in the step-down casing is stirred by the insulating oil pump or circulated in the step-down casing. Therefore, cooling of the step-down circuit in the step-down casing can be promoted.

The motor-driven liquid pump as still another aspect according to the invention for achieving the above-described object,
A submerged pump that is at least partially disposed in the liquid and that pumps the liquid, a motor that is disposed in the liquid and that drives the submerged pump, a step-down device, and a suction from the step-down device in the submerged pump And a cylindrical liquid guide that extends to the mouth and covers the outer peripheral side of the step-down device and the outer peripheral side of the submerged pump . The step-down device includes a step-down circuit that lowers the voltage of AC power from the outside to a voltage that matches the driving of the motor and supplies the AC power that has dropped to the motor, and a step-down circuit that is attached to the motor casing of the motor. And a step-down casing for covering. The liquid guide forms a liquid flow path for flowing the liquid between an inner peripheral side of the liquid guide, an outer peripheral side of the step-down device, and an outer peripheral side of the submerged pump, based on the step-down unit, to the side where the liquid pump is present on the opposite side, to have a opening for guiding the liquid to the inside of itself.

  In the electric submerged pump, external liquid flows into the suction port of the submerged pump through the liquid flow path formed by the liquid guide. For this reason, the flow velocity of the liquid flowing on the outer peripheral side of the step-down device is higher than the flow velocity of the liquid flowing on the outer peripheral side of the step-down device when there is no liquid guide. Therefore, in the electric liquid submersible pump, the heat transfer coefficient between the step-down casing and the liquid is increased, and the heat radiation from the step-down device can be promoted.

  In the motor-driven liquid pump having the liquid guide, the step-down device may include a turbulent flow promoting portion protruding outward from the step-down device casing.

  Since the electric submerged pump has a turbulent flow promoting portion that protrudes outward from the step-down casing, the liquid flowing along the step-down casing becomes turbulent. For this reason, the electric liquid submersible pump has a high heat transfer rate between the step-down casing and the liquid, and can promote heat radiation from the step-down device.

  In any one of the above-described submerged pumps, the step-down device is an inverter, the inverter includes the step-down circuit, and converts the AC frequency of AC power supplied to the motor, and the inverter And an inverter casing that covers the circuit and is attached to the motor casing.

  In the electric liquid submersible pump, the number of revolutions of the motor rotation shaft can be changed by changing the AC frequency of the AC electric power sent to the motor of the electric liquid submerged pump by the inverter. For this reason, the rotation speed of the pump rotation shaft connected to the motor rotation shaft can be changed, and as a result, the discharge amount of the liquid L in the submerged pump can be increased or decreased. That is, in the electric submerged pump, the amount of liquid discharged from the submerged pump can be changed by operating the inverter.

  Further, in the electric liquid submersible pump, it is not necessary to arrange an inverter on the ground, so that the ground space can be effectively utilized. In particular, when the electric submersible pump is used in a submarine oil field, it is possible to effectively use the offshore platform with large installation space restrictions.

  The motor-driven liquid pump having the inverter includes a Peltier element having a heat absorbing part and a heat radiating part. The inverter circuit has a heating element, and the heat absorbing part of the Peltier element is bonded to the heating element. It may be.

  In the electric liquid submersible pump, heat dissipation of the heat generating element of the inverter circuit can be promoted.

  In this case, you may provide the heat sink which thermally connects the said thermal radiation part of the said Peltier device, and the said inverter casing.

  In the electric liquid submersible pump, heat from the heating element of the inverter circuit can be radiated to the outside through the heat sink and the inverter casing.

  Further, in any one of the above-described submerged pumps, the step-down device is a transformer, and the transformer covers the voltage step-down circuit and the voltage change circuit, and is attached to the motor casing. A transformer casing.

An electric liquid submersible pump system as one aspect according to the invention for achieving the above object is as follows:
The electric submersible pump having the transformer, an external inverter that is installed outside the liquid and converts an AC frequency of external AC power, the external inverter, and the transformer of the electric submersible pump And a cable for electrically connecting the two.

  In the electric submerged pump system, the rotational speed of the motor rotation shaft can be changed by changing the AC frequency of the AC power sent to the motor of the electric submerged pump by the out-of-liquid inverter. For this reason, the rotation speed of the pump rotation shaft connected to the motor rotation shaft can be changed, and as a result, the amount of liquid discharged from the submerged pump can be increased or decreased. That is, in the electric submerged pump, the amount of liquid discharged from the submerged pump can be changed by operating the out-of-liquid inverter.

  Further, in the electric liquid submersible pump system, since the inverter is installed outside the liquid, the inverter can be easily repaired or inspected.

An electric submerged pump system according to another aspect of the invention for achieving the above object
The electric liquid pump having the transformer, an external inverter that is installed outside the liquid and converts an alternating current frequency of AC power from the outside, and an AC power that is installed outside the liquid and is supplied from the external inverter A submerged transformer that boosts the voltage of the power supply, and a cable that electrically connects the submerged transformer and the transformer of the submerged pump.

  Also in the electric submerged pump system, the discharge amount of the liquid in the submerged pump can be changed by operating the submerged inverter. Moreover, in the said electric submerged pump system, since the voltage of the alternating current power from a submerged inverter is boosted with a submerged transformer, the inverter which processes low voltage | pressure alternating current power can be used as a submerged inverter.

  The cost of an inverter that can process high-voltage AC power is very high compared to the cost of an inverter that processes low-voltage AC power. For this reason, in the said electric liquid submersible pump system, the cost regarding a liquid outside inverter can be held down.

  According to one embodiment of the present invention, power loss can be suppressed.

It is explanatory drawing which shows the structure of the pump system in electric liquid in 1st embodiment which concerns on this invention. It is sectional drawing of the pump in electric liquid in 1st embodiment which concerns on this invention. It is a sectional view of a pressure equalization seal mechanism, a motor, and a transformer in a first embodiment concerning the present invention. It is explanatory drawing which shows the structure of the pump system in electrically driven liquid in 2nd embodiment which concerns on this invention. It is explanatory drawing which shows the structure of the pump system in electric liquid in 3rd embodiment which concerns on this invention. It is explanatory drawing which shows the structure of the inverter circuit in 3rd embodiment which concerns on this invention. It is explanatory drawing which shows the structure of the inverter circuit of the modification in 3rd embodiment which concerns on this invention. It is sectional drawing of the pressure equalizing seal mechanism, motor, and transformer in 3rd embodiment which concerns on this invention. It is sectional drawing of the pressure equalization seal mechanism of the 1st modification in 3rd embodiment which concerns on this invention, a motor, and a transformer. It is sectional drawing of the pressure equalization seal mechanism of the 2nd modification in 3rd embodiment which concerns on this invention, a motor, and a transformer. It is sectional drawing of the pressure equalization seal mechanism of the 3rd modification in 3rd embodiment which concerns on this invention, a motor, and a transformer. It is principal part sectional drawing of the inverter of the 4th modification in 3rd embodiment which concerns on this invention.

  Hereinafter, various embodiments and various modifications of the submerged pump system according to the present invention will be described in detail with reference to the drawings.

  The motor-driven submersible pump system in various embodiments and various modifications is a system that pumps liquid in a vertical shaft dug down vertically from the ground or the like to the ground or the like. Specifically, the electric submersible pump system in various embodiments and various modifications is a system that pumps crude oil from an oil well that is a shaft. However, the present invention is not limited to the one that pumps crude oil, and may be one that pumps water, hot water, or the like flowing in the ground.

"First Embodiment of Electric Liquid Pump System"
A first embodiment of a submerged pump system according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the submerged pump system of the present embodiment includes a submerged pump 10 that pumps the liquid L in the shaft H to the ground, and a pipe 1 that guides the liquid L from the submerged pump 10 to the ground. And a wellhead 2, a ground inverter (external inverter) 3 that changes the AC frequency of the AC power supplied to the submersible pump 10, and AC power from the ground inverter 3 is sent to the submersible pump 10. And a power transmission cable 5.

  Both the ground inverter 3 and the wellhead device 2 are installed on the ground. A pipe 1 is connected to the wellhead device 2. Further, the wellhead device 2 supports a power transmission cable 5 that is mostly disposed in the shaft H.

  The electric submerged pump 10 includes a submerged pump 11, a motor 31 that drives the submerged pump 11, a pressure equalizing seal mechanism 41 that seals the motor 31, and a voltage of AC power sent from the power transmission cable 5. A transformer (step-down) 51 that steps down to a pressure suitable for driving 31 and a sensor 81 are provided.

  The submerged pump 11, the pressure equalization seal mechanism 41, the motor 31, the transformer 51, and the sensor 81 are disposed in the vertical shaft H from the top to the bottom in this order. A suction port 14 i is formed in the lower part of the submerged pump 11, and a discharge port 14 o is formed in the upper part of the submerged pump 11. The pipe 1 connects the discharge port 14 o of the submerged pump 11 and the wellhead device 2. The power transmission cable 5 is connected to the transformer 51 via the pipe 1, the submerged pump 11, the seal mechanism, and the outer peripheral side of the motor 31 via the wellhead device 2 from the ground inverter 3. Examples of the sensor 81 include a sensor that detects the temperature and pressure of the liquid L at the position where the submerged pump 11 is disposed, and a sensor that detects vibration of the submerged pump 11. Signals from these sensors are sent to the ground via, for example, a conductor of the power transmission cable 5 or a signal cable different from the power transmission cable 5.

  Here, it is assumed that the rated voltage of the motor 31 is 440V, for example. Moreover, the voltage of the alternating current power sent to the ground inverter 3 and the voltage of the alternating current power which flows through the power transmission cable 5 shall be 6600V, for example. In addition, the rated voltage 440V of the motor 31 and the voltage 6600V of AC power flowing through the power transmission cable 5 are examples, and the present embodiment is not limited to this. That is, high-voltage AC power having a voltage higher than the rated voltage of the motor 31 may flow through the power transmission cable 5.

  As shown in FIG. 2, the submerged pump 11 includes a pump unit 15 and a separator unit 21. The pump unit 15 is rotatable about the axis A and a columnar main body rotation shaft 16 that is long in the axial direction in which the axis A extends, a blade 17 fixed to the main body rotation shaft 16, and the main body rotation shaft 16. The bearing 18 to support and the cylindrical main body casing 19 which covers these are provided. The separator unit 21 is rotatable about the axis A and a columnar separator rotating shaft 22 that is long in the axial direction in which the axis A extends, a blade 23 fixed to the separator rotating shaft 22, and the separator rotating shaft 22. The bearing 24 to support and the cylindrical separator casing 25 which covers these are provided. Both the main body casing 19 and the separator casing 25 have a cylindrical shape with the axis A as the center.

  The axial direction of the submerged pump 11 is vertical when the submerged pump 11 is installed in the shaft H. Hereinafter, the submerged pump 11 will be described in a state where the submerged pump 11 is installed in the shaft H in order to easily understand the submerged pump system.

  The separator rotation shaft 22 is connected to the lower side of the main body rotation shaft 16. The separator casing 25 is connected to the lower side of the main body casing 19. That is, the separator unit 21 is disposed on the lower side with respect to the pump unit 15. The pump rotating shaft 12 includes the separator rotating shaft 22 and the main body rotating shaft 16. The pump casing 13 includes the separator casing 25 and the main body casing 19. In the separator casing 25, in other words, in the lower portion of the pump casing 13, the aforementioned suction port 14 i for sucking the liquid L in the shaft H is formed. The above-described discharge port 14 o is formed in the upper portion of the pump casing 13. The separator casing 25 is further formed with a foreign matter discharge port 26 at an upper portion of the suction port 14i.

  The blades 23 of the separator unit 21 apply centrifugal force to the liquid L that has flowed into the separator casing 25 from the suction port 14i. Foreign matter such as sand and stone in the liquid L is separated from the liquid L by this centrifugal force. The separated foreign matter is discharged out of the separator casing 25 from the foreign matter discharge port 26 of the separator casing 25. The liquid L from which the foreign matter has been separated flows into the main body casing 19. The liquid L is sent upward by the rotation of the main body rotation shaft 16 and flows into the pipe 1 from the discharge port 14 o of the pump casing 13. The liquid L that has flowed into the pipe 1 is sent to the wellhead device 2 through the pipe 1.

  As shown in FIG. 3, the motor 31 includes a stator 35, a motor rotation shaft 32, a rotor 36 attached to the motor rotation shaft 32, a motor casing 33 that covers the stator 35 and the rotor 36, and a motor rotation shaft 32. And a bearing 34 that rotatably supports the motor. The motor rotation shaft 32 has a columnar shape that is long in the axial direction about the axis A. The rotor 36 is fixed to the motor rotation shaft 32. The motor casing 33 has a cylindrical shape with the axis A as the center. The stator 35 is fixed to the inner peripheral surface of the motor casing 33 so as to face the stator 35 in the radial direction with respect to the axis A. The axis A of the motor 31 is located on the extension line of the axis A of the submerged pump 11. Therefore, the motor rotating shaft 32 extends in the vertical direction. The motor rotating shaft 32 has an upper end (first end) 32a and a lower end (second end) 32b. An upper end portion 32 a of the motor rotation shaft 32 protrudes upward from the motor casing 33 and is connected to the pump rotation shaft 12. The motor casing 33 is filled with insulating oil I.

  The pressure equalizing seal mechanism 41 prevents the liquid L in the shaft H from flowing into the motor casing 33 from the gap between the outer periphery of the motor rotating shaft 32 partially protruding from the motor casing 33 and the motor casing 33. prevent. The pressure equalizing seal mechanism 41 is disposed between the pump casing 13 and the motor casing 33. The pressure equalizing seal mechanism 41 is formed with a cylindrical seal casing 43 centering on the axis A of the motor rotating shaft 32 and a flow path formation that forms a meandering flow path 45 that meanders in cooperation with the seal casing 43 in the seal casing 43. Member 44.

  The meandering channel 45 has a liquid inlet 47 that guides the liquid L in the shaft H to the inside thereof, and a communication port 46 that communicates with the motor casing 33. The meandering channel 45 meanders in the vertical direction within the seal casing 43. The liquid inlet 47 is formed in the upper part of the seal casing 43. The communication port 46 is the above-described gap between the outer periphery of the motor rotating shaft 32 and the motor casing 33. The meandering channel 45 is a continuous channel from the liquid inlet 47 to the communication port 46. A portion of the meandering channel 45 on the communication port 46 side is filled with insulating oil I. In addition, the portion on the liquid inlet 47 side in the meandering channel 45 is filled with the liquid L flowing into the meandering channel 45 from the liquid inlet 47. The liquid L and the insulating oil I are in contact with each other in the meandering channel 45. In the position where the liquid L and the insulating oil I are in contact with each other in the meandering flow path 45, the insulating oil I is positioned above the liquid L. The position where the liquid L and the insulating oil I are in contact with each other forms the liquid contact portion 48 of the meandering channel 45.

  In the present embodiment, the specific gravity of the liquid L is greater than the specific gravity of the insulating oil I so that the liquid L positioned on the lower side does not float in the insulating oil I positioned on the upper side with respect to the liquid contact portion 48. large. That is, here, the insulating oil I having a specific gravity smaller than the specific gravity of the liquid L in the shaft H is selected.

  Since the liquid L in the shaft H flows from the liquid inlet 47 into the seal casing 43, the pressure inside the seal casing 43 is the same as the pressure outside the seal casing 43. Further, since the inside of the seal casing 43 and the inside of the motor casing 33 communicate with each other through the communication port 46, the pressure inside the motor casing 33 becomes the same as the pressure inside the seal casing 43, and as a result, the outside of the seal casing 43. And the pressure outside the motor casing 33 is the same. Therefore, even when the depth of the electric liquid pump 10 is deepened and the pressure of the liquid L is increased at the position where the electric liquid pump 10 is installed, the electric liquid pump 10 is provided between the motor casing 33 and the outside of the motor casing 33. Pressure equalization is achieved. For this reason, in this embodiment, the infiltration of the liquid L into the motor 31 due to the external pressure can be prevented regardless of the installation depth of the electric liquid pump 10, and the pressure difference between the inside and outside of the motor 31 can be substantially eliminated. Therefore, the motor 31 can be prevented from being damaged.

  The transformer 51 includes a transformer circuit 54 and a transformer casing 53 that is cylindrical with the axis A as the center and covers the transformer circuit 54. The transformer circuit 54 is a circuit that converts the 6600 V AC power voltage sent from the power transmission cable 5 into 440 V AC power that matches the rated voltage of the motor 31. That is, the transformer circuit 54 is a step-down circuit. Moreover, the transformer casing 53 that covers the transformer circuit 54 is a step-down casing. The transformer circuit 54 supplies 440 V AC power to the motor 31.

  The transformer casing 53 is also filled with insulating oil I. The upper end of the transformer casing 53 and the lower end of the motor casing 33 are connected. The inside of the motor casing 33 and the inside of the transformer casing 53 are partitioned by a wall plate 38 that forms the motor casing 33 or the transformer casing 53. The wall plate 38 is formed with a communication hole 39 that allows the motor casing 33 and the transformer casing 53 to communicate with each other. For this reason, the pressure in the transformer casing 53 becomes the same as the pressure in the motor casing 33, and as a result, the pressure outside the motor casing 33 and outside the transformer casing 53 becomes the same. Therefore, even if the installation depth of the electric liquid pump 10 becomes deeper and the pressure of the liquid L at the position where the electric liquid pump 10 is installed becomes higher, damage to the transformer 51 due to external pressure can be prevented.

  In the present embodiment, the rotational speed of the motor rotating shaft 32 can be changed by changing the AC frequency of the AC power sent to the motor 31 of the submerged liquid pump 10 by the ground inverter 3, or changing the voltage depending on the case. For this reason, the rotation speed of the pump rotation shaft 12 connected to the motor rotation shaft 32 can be changed, and as a result, the discharge amount of the liquid L in the submerged pump 11 can be increased or decreased. That is, the discharge amount of the liquid L in the submerged pump 11 can be changed by operating the ground inverter 3.

  In the present embodiment, since the inverter 3 is installed on the ground, the inverter 3 can be easily repaired or inspected.

  Further, in the present embodiment, the pressure equalization between the motor casing 33 and the outside of the motor casing 33 and the pressure equalization between the inside of the transformer casing 53 and the outside of the transformer casing 53 are attempted. For 33 and 53, a robust pressure-resistant structure is not required. For this reason, in this embodiment, the manufacturing (or purchase) cost of the motor 31 and the transformer 51 can be suppressed. Furthermore, in this embodiment, since the weight reduction of the motor 31 and the transformer 51 is achieved, the installation cost of the submerged pump 10 can be suppressed.

  By the way, the submerged pump 10 may be located at a depth of about 1000 m underground, or sometimes installed at a position of 3000 m or more underground. For this reason, the power transmission cable 5 that sends power to the motor 31 of the submerged liquid pump 10 is also a long cable of 1000 m or longer. Thus, when the length of the power transmission cable 5 is increased, the power loss in the power transmission cable 5 cannot be ignored. In the present embodiment, a voltage higher than the rated voltage of the motor 31 of the submerged liquid pump 10, specifically, AC power of 6600 V flows through the power transmission cable 5. Then, the AC power of 6600 V is stepped down to 440 v that is the rated voltage of the motor 31 by the transformer 51 of the submerged liquid pump 10, and then this AC power is supplied to the motor 31. That is, in the present embodiment, high-voltage AC power can flow through the power transmission cable 5. The power loss of the power transmission cable 5 is proportional to the square of the value of the current flowing through the power transmission cable 5. For this reason, in this embodiment, the current value of this electric power becomes small by enlarging the voltage value of the electric power which flows through the power transmission cable 5, and the power loss in the power transmission cable 5 can be suppressed.

  Moreover, in this embodiment, since the high voltage alternating current power can be sent through the power transmission cable 5, the outer diameter of the conductor which forms the power transmission cable 5 can be made small. Can also be reduced. For this reason, in this embodiment, the manufacturing (or purchase) cost of the power transmission cable 5 can be suppressed. Furthermore, in this embodiment, since the total weight of the power transmission cable 5 is reduced, the installation cost of the power transmission cable 5 can also be suppressed.

"Second Embodiment of Electric Liquid Pump System"
A second embodiment of the submerged pump system according to the present invention will be described with reference to FIG.

  As in the first embodiment, the submerged pump system of the present embodiment is a submerged pump 10 that pumps the liquid L into the shaft H, and a pipe that leads the liquid L from the submerged pump 10 to the ground. 1, a wellhead 2, and a ground inverter (external inverter) 3 a that changes the AC frequency of the AC power supplied to the submerged pump 10. In the present embodiment, the submerged pump 10, the pipe 1, and the wellhead device 2 are the same as those in the first embodiment. The electric submerged pump system of the present embodiment further includes a ground transformer (external transformer) 4 that boosts AC power from the ground inverter 3a, and AC power boosted by the ground transformer 4 to the electric submersible pump. And a power transmission cable 5 to be sent to 10.

  The ground transformer 4 is installed on the ground in the same manner as the ground inverter 3 a and the wellhead device 2.

  For example, 440 V AC power is sent to the ground inverter 3a of the present embodiment. The ground inverter 3a changes the AC frequency of the AC power. However, the ground inverter 3a outputs AC power without changing the voltage. Therefore, this ground inverter 3a outputs 440v of AC power.

  The ground transformer 4 increases the voltage of the AC power from the ground inverter 3a. Specifically, the ground transformer 4 boosts the AC power of 440V to 6600V. The power transmission cable 5 sends 6600 V AC power from the ground transformer 4 to the transformer 51 of the submerged pump 10. In the present embodiment, the voltage of the AC power flowing through the power transmission cable 5 may be higher than the rated voltage of the motor 31 of the submerged pump 10, and is not limited to 6600V. Moreover, the voltage of the alternating current power sent to the ground inverter 3a should just be lower than the voltage of the alternating current power which flows through the power transmission cable 5, and is not limited to 440V.

  Also in this embodiment, the 6600V AC power sent to the transformer 51 of the submerged pump 10 is stepped down to 440V AC power by the power transmission cable 5 in the same manner as the above embodiment. To the motor 31 of the submerged pump 10.

  Therefore, also in this embodiment, the power loss in the power transmission cable 5 can be suppressed as in the first embodiment. Furthermore, also in this embodiment, the manufacturing (or purchase) cost and installation cost of the power transmission cable 5 can be suppressed.

  By the way, 6600V AC power is sent to the ground inverter 3a of the first embodiment. That is, the ground inverter 3a of the first embodiment has a specification capable of processing 6600V AC power. On the other hand, 440V AC power is sent to the ground inverter 3a of the present embodiment. That is, the specification which can process 440V alternating current power is enough for the ground inverter 3a of this embodiment. The cost of an inverter that can process high-voltage AC power is very high compared to the cost of an inverter that processes low-voltage AC power. For this reason, in this embodiment, the cost regarding an inverter can be held down rather than the said 1st embodiment. However, in this embodiment, since the ground transformer 4 is provided in addition to the transformer 51 of the submerged pump 10, the cost related to the transformer is higher than that in the first embodiment.

  The increase in the cost of the high-voltage inverter with respect to the cost of the low-voltage inverter is often larger than the increase in cost due to the increase of one transformer. For this reason, in the electro-hydraulic pump system of this embodiment, cost may be able to be suppressed compared with the electro-hydraulic pump system in said 1st embodiment.

“Third embodiment of pumping submersible system”
A third embodiment of the submerged pump system according to the present invention will be described with reference to FIGS.

  The submerged pump system of this embodiment includes a submerged pump 10a that pumps liquid L into the shaft H, a pipe 1 that guides the liquid L from the submerged pump 10a to the ground, and a wellhead. 2 and a power transmission cable 5 for sending AC power from the ground to the submerged pump 10a.

  For example, 6600 V alternating current flows through the power transmission cable 5 of the present embodiment, as in the above embodiments.

  The electric submerged pump 10a of this embodiment includes a submerged pump 11, a motor 31 that drives the submerged pump 11, a pressure equalizing seal mechanism 41 that seals the motor 31, an inverter 61, and a sensor 81. ing. The submerged pump 11, the motor 31, the pressure equalizing seal mechanism 41, and the sensor 81 in the electric submerged pump 10a of this embodiment are the same as those of the above embodiments. Therefore, the submerged pump 10a of this embodiment is obtained by replacing the transformer 51 in each of the above embodiments with an inverter 61.

  The inverter 61 of this embodiment includes an inverter circuit 64 and an inverter casing 63 that covers the inverter circuit 64. As shown in FIG. 6, the inverter circuit 64 includes a step-down circuit (AC / AC) 65 that lowers the voltage of AC power from the power transmission cable 5, and AC / DC conversion that converts AC power from the step-down circuit 65 into DC power. A circuit 66 and a DC / AC conversion circuit 67 that converts the DC power from the AC / DC conversion circuit 66 into AC power having a predetermined frequency. Therefore, the inverter 61 of the present embodiment changes the voltage and frequency of AC power from the power transmission cable 5. The step-down circuit 65 reduces the voltage of 6600 V AC power from the power transmission cable 5 to 440 V. AC power from the DC / AC conversion circuit 67 is sent to the motor 31. The control signal to the inverter circuit 64 is sent from the ground via a conductor of the power transmission cable 5 or a signal cable different from the power transmission cable 5, for example.

  The inverter circuit 64 need not have the above configuration. That is, any configuration may be used as long as it has a function of reducing the voltage and a function of converting the frequency of the power. For example, as shown in FIG. 7, the inverter circuit 64a includes an AC / DC conversion circuit 65a that converts AC power from the power transmission cable 5 into DC power, and a step-down that reduces the pressure of the DC power from the AC / DC conversion circuit 65a. A circuit (DC / DC) 66a and a DC / AC conversion circuit 67a that converts the DC power from the step-down circuit 66a into AC power having a predetermined frequency may be included.

  As shown in FIG. 8, the inverter casing 63 has a cylindrical shape with the axis A as the center. The upper end of the inverter casing 63 and the lower end of the motor casing 33 are connected. The motor casing 33 and the inverter casing 63 are partitioned by a wall plate 38 that forms the motor casing 33 or the inverter casing 63. The wall plate 38 is formed with a communication hole 39 that allows the motor casing 33 and the inverter casing 63 to communicate with each other. The inverter casing 63 is filled with the insulating oil I as in the motor casing 33. For this reason, the pressure in the inverter casing 63 is the same as the pressure in the motor casing 33, and as a result, the pressure is the same as the pressure outside the motor casing 33 and the inverter casing 63. Therefore, even if the depth of installation of the electro-hydraulic pump 10a becomes deep and the pressure of the liquid L at the position where the electro-hydraulic pump 10a is installed increases, damage to the inverter 61 due to external pressure can be prevented.

  In this embodiment, 6600V AC power sent to the inverter 61 of the submerged pump 10a by the power transmission cable 5 is stepped down to 440V by the step-down circuit 65 (or 66a) of the inverter 61, and then is submerged in the motor fluid. It is supplied to the motor 31 of the pump 10a.

  Therefore, also in this embodiment, the power loss in the power transmission cable 5 can be suppressed as in the above embodiments. Furthermore, also in this embodiment, the manufacturing (or purchase) cost and installation cost of the power transmission cable 5 can be suppressed.

  Moreover, in this embodiment, as a result of connecting the inverter casing 63 to the motor casing 33, the distance between the motor 31 and the inverter 61 can be shortened, and harmonic countermeasures can be minimized. Furthermore, loss due to the sine wave filter can be suppressed.

  Furthermore, in this embodiment, the inverter casing 63 is connected to the motor casing 33, the inverter 61 is disposed in the shaft H, and it is not necessary to dispose the inverter on the ground, so that the ground space can be effectively used. . In particular, when the submersible oil pump system according to the present embodiment is used in a submarine oil field, it is possible to effectively use the offshore platform with large installation space restrictions.

"First variant of electric liquid pump system"
A first modification regarding the submerged pump system of the third embodiment will be described with reference to FIG.

  The electro-hydraulic pump 10b of the present modification also includes the sub-liquid pump 11, the pressure equalizing seal mechanism 41, the motor 31, and the inverter 61, like the electro-hydraulic pump 10a of the third embodiment.

  The lower end portion (second end portion) 32 b of the motor rotating shaft 32 of this modification penetrates the wall plate 38 forming the motor casing 33 or the inverter casing 63 and enters the inverter casing 63. A stirring blade 77 is provided at the lower end 32 b in the inverter casing 63.

  The stirring blade 77 rotates as the motor rotating shaft 32 rotates. For this reason, the insulating oil I in the inverter casing 63 is stirred by the stirring blades 77 or circulates in the inverter casing 63. Therefore, in this modification, cooling of the inverter circuit 64 can be promoted.

  The present modification is applied to the electric liquid pump 10a of the third embodiment, but may be applied to the electric liquid pump 10 of the first and second embodiments as necessary. Good. In this case, the lower end portion 32 b of the motor rotation shaft 32 protrudes into the transformer casing 53, and the stirring blade 77 is provided on the lower end portion 32 b of the motor rotation shaft 32.

"Second variant of pump system for electric liquid"
The 2nd modification regarding the pump system in electric liquid of the said 3rd embodiment is demonstrated using FIG.

  The electro-hydraulic pump 10c according to the present modification also includes the sub-liquid pump 11, the pressure equalizing seal mechanism 41, the motor 31, and the inverter 61, like the electro-hydraulic pump 10a of the third embodiment.

  An insulating oil pump 78 that sucks the insulating oil I in the inverter casing 63 and discharges the insulating oil I is disposed in the inverter casing 63 of this modification. This insulating oil pump 78 is driven by a motor (not shown). This motor is driven by electric power from a drive circuit (not shown). For example, the drive circuit converts AC power sent to the inverter circuit 64 into power suitable for driving the motor, and supplies this power to the motor.

  In this modification, the insulating oil I in the inverter casing 63 is stirred by the insulating oil pump 78 or circulates in the inverter casing 63. Therefore, also in this modification, cooling of the inverter circuit 64 can be promoted similarly to the first modification.

  The present modification is applied to the electric liquid pump 10a of the third embodiment, but may be applied to the electric liquid pump 10 of the first and second embodiments as necessary. Good. In this case, the insulating oil pump 78 is provided in the transformer casing 53.

“Third Modification of Electric Submersible Pump System”
The 3rd modification regarding the pump system in electric liquid of the said 3rd embodiment is demonstrated using FIG.

  Similarly to the electric submerged pump 10a of the third embodiment, the electric submerged pump 10d of the present modification also includes the submerged pump 11, the pressure equalizing seal mechanism 41, the motor 31, and the inverter 61. The electric-liquid sub-pump 10 d of this modification further includes a cylindrical liquid guide 71.

  The liquid guide 71 has a cylindrical shape centering on the axis A, and is continuous from the lower end of the inverter 61 to the suction port 14 i of the submerged pump 11. The liquid guide 71 covers the outer peripheral side of the inverter 61, the outer peripheral side of the motor 31, the outer peripheral side of the pressure equalizing seal mechanism 41, and the outer peripheral side of the submerged pump 11. The liquid guide 71 includes a shaft between the inner peripheral side of the liquid guide 71, the outer peripheral side of the inverter 61, the outer peripheral side of the motor 31, the outer peripheral side of the pressure equalizing seal mechanism 41, and the outer peripheral side of the submerged pump 11. A liquid flow path 72 for flowing the liquid L in H is formed. The liquid flow path 72 has an opening 73 at its lower end.

  The liquid L in the shaft H passes through the liquid flow path 72 formed by the liquid guide 71 and flows into the suction port 14 i of the submerged pump 11. The channel area of the liquid channel 72 is smaller than the channel area in the shaft H. For this reason, the flow velocity of the liquid L flowing on the outer peripheral side of the inverter casing 63 is higher than the flow velocity of the liquid L flowing on the outer peripheral side of the inverter casing 63 when the liquid guide 71 is not provided. Therefore, in this modification, the heat transfer rate between the inverter casing 63 and the liquid L is increased, and heat dissipation from the inverter 61 can be promoted.

  In this modification, in order to further promote heat dissipation from the inverter 61, the inverter casing 63 may be provided with a turbulent flow promoting portion 62 such as a fin or a pin protruding outward from the outer surface of the inverter casing 63. The turbulent flow promoting unit 62 may be further provided in the pump casing 13. As an example of the turbulent flow promoting unit 62, as described above, there are fins and pins that disturb the flow of the liquid L between the outer peripheral side of the inverter casing 63 and the liquid guide 71. However, a plurality of fins may be provided for the purpose of increasing the heat transfer area on the outer surface of the inverter casing 63. In this case, the plurality of fins protrude outward from the outer surface of the inverter casing 63 and extend in the vertical direction along the flow direction of the liquid L.

  The present modification is applied to the electric liquid pump 10a of the third embodiment, but may be applied to the electric liquid pump 10 of the first and second embodiments as necessary. Good. In this case, the liquid guide 71 covers the outer peripheral side of the transformer casing 53.

“Fourth Modification of Electric Submersible Pump System”
The 4th modification regarding the pump system in electric liquid of the said 3rd embodiment is demonstrated using FIG.

  The electro-hydraulic pump according to the present modification also includes an under-water pump, a pressure equalizing seal mechanism, a motor, and an inverter, similar to the electro-hydraulic pump 10a of the third embodiment. The inverter 61e in the motor-driven liquid pump of this modification includes a Peltier element 68.

  The inverter circuit 64 includes a substrate 64b and a plurality of heating elements 64c mounted on the substrate 64b. The Peltier element 68 is bonded to the surface of the heat generating element 64c. The Peltier element 68 includes a heat absorbing portion 68a that absorbs heat and a heat radiating portion 68b that releases this heat. The heat absorbing portion 68a of the Peltier element 68 is bonded to the surface of the heating element 64c.

  When a current flows through the Peltier element 68, heat is transferred from a part of the Peltier element 68 to another part. A part of the Peltier element 68 forms the above-described heat absorbing portion 68a, and the other portion forms the above-described heat radiating portion 68b. The Peltier element 68 is driven by electric power from a drive circuit (not shown). For example, the drive circuit converts the AC power sent to the inverter circuit 64 into a DC current suitable for element driving, and supplies the DC power to the Peltier element 68.

  In this modification, heat dissipation of the heating element 64c of the inverter circuit 64 can be promoted. In order to further promote this heat radiation, it is preferable to provide a heat sink 69 between the heat radiation portion 68 b of the Peltier element 68 and the inner surface of the inverter casing 63. The heat sink 69 is preferably formed of a material having a higher thermal conductivity than the material forming the inverter casing 63. A part of the heat sink 69 is in contact with the heat radiating portion 68 b of the Peltier element 68, and the other part is in contact with the inner surface of the inverter casing 63. For this reason, the heat sink 69 plays a role of thermally connecting the heat dissipation portion 68b of the Peltier element 68 and the inverter casing 63.

  This modification is suitable as a method for cooling the inverter 61 when the temperature of the liquid L at the position where the inverter 61e is disposed is high and the inverter 61 cannot be sufficiently cooled by the method of the third modification. It is.

  1: piping, 2: wellhead, 3, 3a: ground inverter (liquid inverter), 4: ground transformer (liquid transformer), 5: power transmission cable, 10, 10a, 10b, 10c, 10d : Electric submersible pump, 11: Submerged pump, 12: Pump rotating shaft, 13: Pump casing, 14i: Suction port, 14o: Discharge port, 15: Pump part, 16: Main body rotating shaft, 17: Blade, 18: Bearing: 19: Main body casing, 21: Separator part, 22: Separator rotating shaft, 23: Blade, 24: Bearing, 25: Separator casing, 26: Foreign substance discharge port, 31: Motor, 32: Motor rotating shaft, 32a: Upper end Part (first end part), 32b: lower end part (second end part), 33: motor casing, 34: bearing, 35: stator, 36: rotor, 38: wall plate, 39: communication hole, 41: pressure equalization seal Structure: 43: Seal casing, 44: Flow path forming member, 45: Serpentine flow path, 46: Communication port, 47: Liquid inlet, 48: Liquid contact part, 51: Transformer (step-down), 53: Transformer Casing (step-down casing) 54: Transformer circuit (step-down circuit) 61, 61e: Inverter (step-down) 62: Turbulence promoting part 63: Inverter casing (step-down casing) 64, 64a: Inverter circuit 64b: substrate, 64c: heating element, 65, 66a: step-down circuit, 68: Peltier element, 68a: heat absorption part, 68b: heat dissipation part, 69: heat sink, 71: liquid guide, 72: liquid channel, 73: opening, 77: stirring blade, 78: insulating oil pump, 81: sensor, H: shaft, I: insulating oil, L: liquid

Claims (15)

A submerged pump that is at least partially disposed in the liquid and pumps the liquid;
A motor arranged in the liquid to drive the submersible pump;
A buck,
A pressure equalizing seal mechanism ;
With
The step-down device lowers the voltage of the AC power from the outside to a voltage suitable for driving the motor and supplies the motor with the reduced AC power. The step-down circuit is attached to the motor casing of the motor. And a step-down casing covering the
The motor includes a stator, a motor rotating shaft, a rotor attached to the motor rotating shaft and rotating relative to the stator integrally with the motor rotating shaft, and the motor casing covering the stator and the rotor. The motor rotating shaft has a first end and a second end, and the first end protrudes from the motor casing;
The submerged pump has a pump rotating shaft connected to the motor rotating shaft,
The pressure equalizing seal mechanism is attached to the motor casing and covers a part of the first end portion of the motor rotating shaft, and a meandering flow path meandering in the seal casing together with the seal casing A flow path forming member for forming
The meandering channel includes a liquid inlet for introducing the liquid into the interior thereof, a communication port communicating with the inside of the motor casing, a liquid flowing in from the liquid inlet, one of the inside of the motor casing and the meandering channel. A liquid contact part for contacting the insulating oil filled in the part,
Electric submersible pump. In the motor-driven liquid pump according to claim 1 ,
A communication hole for communicating the inside of the motor casing and the inside of the step-down casing is formed at the boundary between the inside of the motor casing and the inside of the step-down casing.
Electric liquid pump. In the electric liquid pump according to claim 1 or 2 ,
The second end of the motor rotation shaft protrudes from the motor casing and enters the step-down casing.
A stirring blade attached to the second end and stirring or circulating the insulating oil filled in the step-down casing;
Electric liquid pump. A submerged pump that is at least partially disposed in the liquid and pumps the liquid;
A motor arranged in the liquid to drive the submersible pump;
A buck,
An insulating oil pump;
With
The step-down device includes a step-down circuit that lowers the voltage of AC power from the outside to a voltage that matches the driving of the motor and supplies the AC power that has dropped to the motor, and a step-down circuit that is attached to the motor casing of the motor. And a step-down casing that covers,
The insulating oil pump is disposed in the step-down device casing, by discharging inhale insulating oil filled in the step-down unit casing, Ru is to or circulated stirred insulating oil filled in the step-down unit casing ,
Electric liquid pump. A submerged pump that is at least partially disposed in the liquid and pumps the liquid;
A motor arranged in the liquid to drive the submersible pump;
A buck,
A cylindrical liquid guide that extends from the step-down device to the suction port in the submerged pump, and covers the outer peripheral side of the step-down device and the outer peripheral side of the submerged pump ;
With
The step-down device includes a step-down circuit that lowers the voltage of AC power from the outside to a voltage suitable for driving the motor and supplies AC power that has been dropped to the motor, and a step-down circuit that is attached to a motor casing of the motor. And a step-down casing that covers,
The liquid guide forms a liquid flow path for flowing the liquid between an inner peripheral side of the liquid guide, an outer peripheral side of the step-down device, and an outer peripheral side of the submerged pump,
The liquid flow path has an opening for guiding the liquid to the inside thereof on the side opposite to the side where the submerged pump exists with respect to the step-down device.
Electric liquid pump. In the motor-driven liquid pump according to claim 4 or 5 ,
Equipped with a pressure equalizing seal mechanism,
The motor includes a stator, a motor rotating shaft, a rotor attached to the motor rotating shaft and rotating relative to the stator integrally with the motor rotating shaft, and the motor casing covering the stator and the rotor. The motor rotating shaft has a first end and a second end, and the first end protrudes from the motor casing;
The submerged pump has a pump rotating shaft connected to the motor rotating shaft,
The pressure equalizing seal mechanism is attached to the motor casing and covers a part of the first end portion of the motor rotating shaft, and a meandering flow path meandering in the seal casing together with the seal casing A flow path forming member for forming
The meandering channel includes a liquid inlet for introducing the liquid into the interior thereof, a communication port communicating with the inside of the motor casing, a liquid flowing in from the liquid inlet, one of the inside of the motor casing and the meandering channel. A liquid contact part for contacting the insulating oil filled in the part,
Electric submersible pump. In the electrohydraulic pump according to any one of claims 1 to 3 , and 5 ,
An insulating oil pump that is disposed in the step-down casing and sucks and discharges the insulating oil that is filled in the step-down casing, thereby stirring or circulating the insulating oil that is filled in the step-down casing.
Electric liquid pump. The electric fluid pump according to any one of claims 1 or et 4,
Continuing between the step-down device and the suction port of the submerged pump, and having a cylindrical liquid guide covering the outer peripheral side of the step-down device and the outer peripheral side of the submerged pump,
The liquid guide forms a liquid flow path for flowing the liquid between an inner peripheral side of the liquid guide, an outer peripheral side of the step-down device, and an outer peripheral side of the submerged pump,
The liquid flow path has an opening for guiding the liquid to the inside thereof on the side opposite to the side where the submerged pump exists with respect to the step-down device.
Electric liquid pump. In the motor-driven liquid pump according to claim 5 or 8 ,
The step-down device has a turbulence promoting portion protruding outward from the step-down casing.
Electric liquid pump. The electric fluid pump according to any one of claims 1 through 9,
The step-down device is an inverter;
The inverter includes the step-down circuit, and includes an inverter circuit that converts an AC frequency of AC power supplied to the motor, and an inverter casing that covers the inverter circuit and is attached to the motor casing.
Electric liquid pump. In the electric liquid pump according to claim 10 ,
Comprising a Peltier element having a heat absorption part and a heat radiation part,
The inverter circuit has a heating element,
The heat generating element has a heat absorbing portion of the Peltier element bonded thereto,
Electric submersible pump. In the electric liquid pump according to claim 11 ,
A heat sink that thermally connects the heat dissipation portion of the Peltier element and the inverter casing;
Electric submersible pump. The electric fluid pump according to any one of claims 1 through 9,
The step-down device is a transformer;
The transformer includes a transformer circuit that forms the step-down circuit, and a transformer casing that covers the transformer circuit and is attached to the motor casing.
Electric liquid pump. A pump in electric liquid according to claim 13 ;
An external inverter that is installed outside the liquid and converts an AC frequency of AC power from the outside;
A cable for electrically connecting the inverter outside the liquid and the transformer of the submerged pump;
Electric submersible pump system. A pump in electric liquid according to claim 13 ;
An external inverter that is installed outside the liquid and converts an AC frequency of AC power from the outside;
An external transformer that is installed outside the liquid and boosts the voltage of the AC power from the external inverter;
A cable for electrically connecting the external transformer and the transformer of the submerged pump;
Electric submersible pump system.

Images