JP5365927B2 - Submerged motor pump wire drawing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an insulation structure capable of preventing liquid leakage and withstanding a high voltage at a through part of an electric wire. <P>SOLUTION: The electric wire of a submerged motor pump is led out of the inside of a casing 7a filled with a pressurized liquid to the outside of low pressure via a lead-out part 12 penetrating an end plate (support) 7f of the casing 7a. In the lead-out part 12, a first insulating tube 12b is provided to enclose the periphery of a rod-shaped conductor 12a and a second insulating tube 12c formed with irregularity on the outer peripheral face along the axial direction is provided to enclose the casing external side periphery of the first insulating tube 12b. The support of the casing 7a is held between the first and second insulating tubes 12b, 12c along the axial direction and the first and second insulating tubes 12b, 12c are fastened along the axial direction via a flange 12d provided at the conductor 12a, a nut 12j screwed to the conductor 12a, a washer 12h and a disc spring 12i. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a wire drawing device that pulls out a wire so as to penetrate a casing filled with pressurized liquid of a submerged motor pump.

  Liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) is stored in a pressure vessel, and a liquefied gas pump is used to take out the liquefied gas from the pressure vessel. . The liquefied gas pump is generally used as a submerged pump in which a driving motor is integrated because the pump main body is used in a state where the pump body is immersed in the liquefied gas liquid in the pressure vessel.

  In this submerged pump, for example, as described in FIG. 2 of Patent Document 1, a rotary shaft that is rotatably supported by upper and lower bearing portions is provided in a pump unit, and an upper side of the rotary shaft is provided. A motor part is provided on the lower side, and a pump part is provided on the lower side so that it is immersed in the liquid of liquefied gas.

  The liquid pressurized in the pump part is sent out of the pressure vessel from the discharge port of the casing through the pipe, while a part of the pressurized liquid is provided in the lower bearing portion and the casing. After flowing into the motor part from the passage hole, circulation is performed from the upper side bearing part and the liquid passage hole provided in the casing through the balance device to the outside of the casing and again into the pump part. It is used for lubrication of parts and cooling of the stator and rotor.

  An electric wire (covered cable) for supplying electric power to the motor portion in the pump unit is pulled out from the casing and connected to an external power supply device outside the pressure vessel.

  Here, the inside of the casing is filled with pressurized liquid, whereas the outside of the casing is filled with liquid before being pressurized by the pump, so that a pressure difference occurs between the inside and outside of the casing. Yes. This pressure difference between the inside and outside of the casing must be maintained in order to circulate the liquid in the casing and to effectively operate the balance device for reducing the thrust load acting on the bearing portion. In the penetration portion of the covered cable arranged to penetrate, closing means such as a gland packing and a fastening gland is provided to keep the liquid tight.

  However, in the penetration part of the coated cable used at extremely low temperature, even if it is configured to be liquid-tight by a closing means such as a gland packing, the component shrinks or deteriorates due to a temperature change from room temperature to cryogenic temperature. The liquid tightness may not be maintained.

  On the other hand, in order to increase the voltage in order to reduce the size of the high-output motor, it is necessary to further strengthen the insulation at the penetration portion of the covered cable.

  Further, there is one described in Patent Document 2, for example, as means for constructing the penetration portion of the covered cable in a liquid-tight manner and reinforcing the insulation. This is because a rod-shaped terminal is attached so as to penetrate the disk-shaped terminal plate, and a sheathed cable is connected to both ends of the terminal, and the periphery of the terminal is surrounded by a fluororesin molded pipe, or a resin-impregnated tape Or the like, and a creeping insulation distance and a space insulation distance necessary between the terminal connection portion and the connecting box are to be secured.

Japanese Patent Publication No. 61-5558 JP-A-10-318179

  However, since the submerged motor pump is used in the cryogenic liquid of the liquefied gas, even if the technique described in Patent Document 2 is adopted, the contraction or deterioration of the parts due to the cryogenic temperature occurs. There is a risk that a gap will be formed between the fixed part of the end of the molded pipe or the fixed part of the resin-impregnated tape winding body and the terminal plate due to the creepage insulation distance between the terminal and the connecting box. There is a possibility that the gap becomes shorter or a gap is formed between the terminal and the terminal plate, so that the liquid leaks into the connecting box and the pressure is released.

  In particular, in order to provide insulation capable of withstanding a high voltage, the insulation portion must be made longer than in the case of a low voltage, and the conductors must be made longer accordingly. When a long material is used at a very low temperature, the material shrinks more, and the problem is that the liquid leaks from the gap and the liquid tightness cannot be maintained.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and penetrates the casing in a state where a pressure difference is generated inside and outside the casing filled with pressurized liquid. Thus, when a wire of a submerged motor pump is drawn out, it is intended to provide a wire drawing structure of a submerged motor pump having an insulating structure that can withstand a high voltage while preventing leakage of liquid in a through portion of the wire. .

In order to achieve the above object, a wire drawing device for a submerged motor pump according to the present invention is immersed in a cryogenic liquid and driven at a high voltage, and the casing is filled with a pressurized liquid. It is drawn in de motor pump from the interior of the casing into a low pressure external to a wire drawing device of the submerged motor pump to which a high voltage is applied, through the casing, the electric wire is connected to both ends, one end a flange portion, a conductor nut forming the threaded threads on the other end, a first insulating tube penetrating the casing surrounds the periphery of the conductor, the casing outside of the first insulating tube surrounds the periphery of the side, comprising a second insulating tube creepage insulation distance and spatial insulation distance uneven outer peripheral surface of the shaft direction are formed is secured, the said first and second Pinching along the support portion provided on said casing by an insulating tube in the axial direction, and the conductor nuts and washers screwed on the conductor and the flange portion, and the conductor by a temperature change of the cryogenic from room temperature, the casing The first and second insulating pipes are tightened in a liquid-tight manner between the first and second insulating pipes along the axial direction via a disc spring that absorbs a gap generated between the first and second insulating pipes and the nut by elastic deformation. It is characterized by.

  According to the electric wire drawing device of the submerged motor pump according to the present invention, the first insulating tube or the first insulating pipe is provided between the conductor at the high potential and the support portion of the casing at the ground potential. A creeping insulation distance and a space insulation distance are secured by a second insulation pipe disposed concentrically with the insulation pipe, and a nut, washer and disc spring exposed from the second insulation pipe and at a high potential. The creeping insulation distance and the space insulation distance are ensured by the unevenness formed on the outer peripheral surface of the second insulating tube. Thereby, the insulation which can endure a high voltage can be comprised with respect to the electric wire pulled out so that it may penetrate a casing.

  In addition, by inserting a disc spring between the nut and washer screwed to the conductor, the difference between the first and second insulating pipes, nut, washer, and disc spring due to the contraction amount due to temperature change from room temperature to cryogenic temperature. Even when each member becomes longer due to the high voltage as well as the low voltage, the gap formed is absorbed by the elastic deformation of the disc spring, and the contact state of the contact surface between the support portion of the casing and the first and second insulating tubes The liquid can be prevented from leaking through the wire lead-out portion.

1 is a cross-sectional view showing a submerged pump unit that employs an electric wire drawing device for a submerged motor pump according to a first embodiment of the present invention. It is sectional drawing which expands and shows the principal part of the electric wire extraction apparatus of the submerged motor pump in FIG. It is sectional drawing which shows the electric wire extraction apparatus of the submerged motor pump by 2nd Embodiment of this invention. It is sectional drawing which shows the electric wire extraction apparatus of the submerged motor pump by 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a submerged pump unit that employs a wire drawing device for a submerged motor pump according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing the main part of the wire drawing device of the submerged motor pump in FIG.

  1 and 2, a pump unit 1 is installed in a pressure vessel that stores liquefied gas, and drives a motor portion and a pump portion that are housed therein to pressurize the liquid of the liquefied gas so as to be external to the pressure vessel. It is configured as a submerged pump that pumps out the air.

  The unit case 2 of the pump unit 1 is composed of a cylindrical container that is divided into upper and lower parts, and the lower unit case 2a is provided with a suction port 3 for sucking liquid such as liquefied gas, and the upper unit case 2b. Are provided with a liquid discharge port 4, a wire drawing pipe 5, and the like.

  In the unit case 2, a pump part 6 is provided at the lower part and a motor part 7 is provided at the upper part. The pump portion 6 is provided with a rotary shaft 8 and a multistage impeller 6b fixed to the rotary shaft 8 in a pump-side casing 6a. In the present embodiment, a six-stage impeller 6b is provided.

  A partition wall 6c is provided in the central portion of the pump portion 6 in the axial direction. The lower three-stage impeller 6b sandwiches the partition wall 6c so as to pressurize the liquid and send it upward. The impeller 6b pressurizes the liquid and sends it out downward.

  A suction port 6d for sucking the liquid in the unit case 2 is provided at the lower end of the pump-side casing 6a. The upper space of the lower three-stage impeller 6b and the upper space of the upper three-stage impeller 6b are connected to the pipe 6e. The lower space of the upper three-stage impeller 6b is connected to a conduit 9c that communicates with the discharge port 4 via conduits 9a and 9b. As a result, the pump portion 6 pressurizes the liquid sucked from the suction port 6d to a pressure half of the set pressure by the lower three-stage impeller 6b, and further pressurizes the set pressure to the discharge port 4 by the upper three-stage impeller 6b. It is designed to send out.

  The upper space of the upper three-stage impeller 6b is filled with a liquid having a pressure that is half the set pressure as described above. This liquid is separated from the lower-side liquid passage hole 7g provided in the casing and the lower-side liquid passage hole 7g. It flows into the motor portion 7 through the bearing portion 7c.

  The motor portion 7 is disposed in a motor-side casing 7a with a rotating shaft 8 common to the pump portion 6 being rotatably supported by upper and lower bearing portions 7b and 7c. A rotor 7d is attached to the rotary shaft 8, and a stator 7e is attached to the inner peripheral surface of the motor side casing 7a at a position opposite to the rotor 7d.

  The liquid having a pressure half of the set pressure flowing into the motor portion 7 passes through the lower bearing portion 7c, passes through the rotor 7d and the stator 7e, passes through the upper bearing portion 7b and the upper liquid passage hole 7h. Further, circulation is performed through the balance device 15 and discharged to the outside of the motor-side casing 7a and again sucked into the suction port 6d. As a result, the bearings 7c and 7d are lubricated and the rotor 7d and the stator 7e are cooled.

  The half-pressurized liquid is also used to operate a balance device for reducing the thrust load. That is, a thrust load due to the weight of the rotor 7d is applied to the bearing portions 7c and 7d via the rotary shaft 8. In order to reduce this thrust load, the rotary shaft 8 is held so as to be movable up and down, and a pressurized liquid is applied to the balance device 15 to float the rotor 7d attached to the rotary shaft 8. Then, the liquid is discharged out of the casing 7a through a gap (not shown) of the balance device. The gap of the balance device is adjusted so that the pressure in the casing 7a is appropriate so that the balance device operates effectively. For this reason, it is necessary to keep the inside of the casing 7a liquid-tight so that pressure does not escape from other than the gap of the balance device.

  Thus, since it is necessary to fill the pressurized liquid in the motor-side casing 7a and maintain the pressure, a pressure difference is generated between the inside and outside of the motor-side casing 7a.

  An electric wire 10 for supplying electric power to the motor portion 7 in the pump unit 1 is drawn out of the casing 7a so as to penetrate the end plate 7f of the motor-side casing 7a, and further through the terminal box 11 to the outside of the pressure vessel. It is designed to be connected to the power supply unit.

  The end plate 7f of the motor-side casing 7a is provided so as to close the inside of the motor-side casing 7a, and supports the upper bearing portion 7b and also supports the lead-out portion 12 of the electric wire 10 in a liquid-tight manner.

  As shown in FIG. 2, the lead-out portion 12 of the electric wire 10 is configured such that a rod-shaped conductor 12a passes through the end plate 7f, and the covered cables 10a and 10b are connected to both ends thereof. Further, the first insulating tube 12b and the second insulating tube 12c arranged concentrically are provided on the outer periphery of the conductor 12a.

  The conductor 12a cuts the covered cables 10a and 10b inside and outside the casing 7a, and prevents liquid from leaking outside through the gap between the covering and the cable.

  The first insulating tube 12b is provided so as to surround the rod-shaped conductor 12a and the flange 12d provided on the conductor 12a and to penetrate the end plate 7f. The first insulating tube 12b is formed with a step portion 12e at the axially intermediate portion of the inner peripheral surface, and the flange portion 12d of the conductor 12a abuts on the step portion 12e to prevent axial movement. In addition, the liquid tightness between the conductor 12a and the first insulating tube 12b is enhanced by the contact surface between the flange 12d and the step 12e.

  The second insulating tube 12c is formed with a smooth inner peripheral surface, but the outer peripheral surface is formed with irregularities along the axial direction so as to surround the upper part of the first insulating tube 12b. And concentrically provided close to the outer peripheral surface of the first insulating tube 12b.

  The first and second insulating pipes 12b and 12c are formed with step portions 12f and 12g on the outer peripheral surface, and the step portions 12f and 12g are used to support the end plate 7f of the motor side casing 7a in the axial direction. Is sandwiched along.

Further, a nut 12j is screwed onto the upper portion of the rod-shaped conductor 12a via a washer 12h and a disc spring 12i. The nut 12j, the washer 12h, the disc spring 12i and the conductor 12a are screwed into the conductor 12a. The first and second insulating tubes 12b and 12c are tightened along the axial direction by the provided flange portion 12d. In this example, a plurality of, for example, two, disc springs 12i are stacked in series to increase the amount of contraction absorbed.

  Thus, the first insulating tube 12b and the first insulating tube 12b are connected between the conductor 12a at the high potential and the flange 12d of the conductor 12a and the end plate (supporting portion) 7f of the motor-side casing 7a at the ground potential. The creeping insulation distance and the space insulation distance are ensured by the second insulating pipe 12c arranged concentrically with the insulating pipe 12b.

  The nut 12j, nut 12h, and disc spring 12i that are exposed from the second insulating tube 12c and are at a high potential have a creeping insulation distance and a space insulation distance due to the unevenness formed on the outer peripheral surface of the second insulating tube. Will be.

  Therefore, it is possible to configure insulation that can withstand high voltage with respect to the lead-out portion 12 of the electric wire 10 that is drawn out so as to penetrate the motor-side casing 7a.

  The lead-out portion 12 is used in an environment with a temperature change from room temperature to extremely low temperature, and the temperature change causes the components such as the first and second insulating tubes 12b and 12c to contract. Even in this case, the normal temperature of the first and second insulating tubes 12b and 12c, the nut 12j, the washer 12h, and the disc spring 12i can be obtained by inserting the disc spring 12i between the nut 12j screwed into the conductor and the washer 12h. The gap formed by the difference in the amount of contraction due to the temperature change from ultra-low temperature is absorbed by the elastic deformation of the disc spring 12i. For this reason, the contact state of the contact surface between the end plate (supporting portion) 7f of the motor-side casing 7a and the step portions 12f and 12g of the first and second insulating tubes 12b and 12c can be maintained, and the drawer portion 12 can be maintained. The liquid can be prevented from leaking through.

  The lead-out portion 12 is provided with cylindrical insulating covers 13 and 14 so as to cover the connection portion between the conductor 12a and the covered cables 10a and 10b.

  FIG. 3 is a cross-sectional view showing a wire drawing structure of a submerged motor pump according to the second embodiment of the present invention. The present embodiment is different from the first embodiment in that the contact surface between the end plate (supporting portion) 7f of the motor side casing 7a and the step portions 22f and 22g of the first and second insulating tubes 12b and 12c. The first and second insulating pipes 12b and 12c are characterized by being inclined with respect to the axial direction.

  With such a configuration, the contact area between the end plate (supporting portion) 7b and the step portions 22f and 22g of the first and second insulating tubes 12b and 12c is increased, and the liquid tightness of the contact portion is increased. Can be increased.

  FIG. 4 is a cross-sectional view showing a wire drawing structure of a submerged motor pump according to a third embodiment of the present invention. This embodiment is different from the first embodiment in that the outer peripheral surface of the second insulating tube 22c is inclined and configured in a conical shape.

  According to the present embodiment, the contact area between the lower surface of the second insulating tube 22c and the end plate (supporting portion) 7f is increased, and the strength of the rod-shaped conductor 12a in the falling direction is increased so that the contact surface contacts. The liquid-tightness of the contact portion can be improved, and the creeping insulation distance of the outer peripheral surface of the second insulating tube 22c is increased, so that the protruding height of the drawer portion 12 is reduced. Can do.

DESCRIPTION OF SYMBOLS 1 ... Pump unit 2 ... Unit case 2a ... Lower unit case 2b ... Upper unit case 3 ... Suction port 4 ... Discharge port 5 ... Electric wire drawing pipe 6 ... Pump part 6a ... Pump side casing 6b ... Impeller 6c ... Partition wall 6d ... Suction Ports 6e, 9a, 9b, 9c ... pipeline 7 ... motor portion 7a ... motor side casing 7b, 7c ... bearing 7d ... rotor 7e ... stator 7f ... end plate (support)
7g, 7h ... Liquid passage hole 8 ... Rotating shaft 10 ... Electric wires 10a, 10b ... Covered cable 11 ... Terminal box 12 ... Lead-out part 12a ... Conductor 12b ... First insulating tube 12c, 22c ... Second insulating tube 12d ... Parts 12e, 12f, 12g, 22f, 22g ... Step 12h ... Washer 12i ... Belleville spring 12j ... Nuts 13 and 14 ... Insulating cover 15 ... Balance device

Claims (3)

In a high-pressure submerged motor pump that is driven at a high voltage by being immersed in a cryogenic liquid and filled with pressurized liquid in the casing, the high voltage is drawn from the inside of the casing to the low pressure outside. A wire pulling device for the submerged motor pump to be applied, wherein the conductor penetrates the casing, the wire is connected to both ends, a hook portion is formed at one end, and a thread is formed at which the nut is screwed to the other end; a first insulating tube penetrating the casing surrounds the periphery of the conductor, the first around the casing outer side of the insulating tube surrounds, creepage insulation distance unevenness is formed on the outer peripheral surface of the axial and comprising a second insulating tube space insulation distance is secured, the sandwiched the support portion provided on the casing by the first and second insulating tube along the axial direction, and the guide Nuts and washers screwed on the conductor and the flange portion, and the conductor by a temperature change of the cryogenic from room temperature, the casing, the first and second insulating tube, disc spring to a gap generated between the nut absorbed by elastic deformation An electric wire drawing device for a submerged motor pump, wherein the first and second insulating pipes are liquid-tightly tightened between the casing and the casing along the axial direction.   The contact surface between the support portion of the casing and the first and second insulating tubes is inclined with respect to the axial direction of the first and second insulating tubes. The electric wire drawing device of the submerged motor pump as described. The electric wire drawing device for a submerged motor pump according to claim 1 or 2, wherein the outer peripheral surface of the second insulating tube is inclined to form a conical shape.

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