JP2007085309A - Submerged motor pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-sealed submerged motor pump having a small outer diameter and short overall length. <P>SOLUTION: A submerged motor pump 1 is equipped with a pump part 11 and a submerged motor 12 arranged in series with the pump part 11. A heat exchanger 13 for executing heat exchange between primary cooling liquid sealed in the submerged motor 12 and secondary cooling liquid which is a pumping liquid in the pump part 11 is formed integrally with the outer periphery of the submerged motor 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a submerged motor pump, and more particularly to a water-sealed submerged motor pump in which a cooling liquid of a submerged motor is sealed against pumping liquid.

  A submerged motor pump is known which is installed in a protective tube and suspended and used for discharging liquefied natural gas stored in underground rocks or discharging bottom water. In particular, when the pumped liquid is liquefied natural gas or the like and is corrosive, a water-sealed submerged motor pump in which the cooling liquid of the submerged motor is sealed against the pumped liquid is used. This water-sealed submerged motor pump includes a water-sealed circulating type that forcibly circulates the coolant of the submerged pump to a heat exchanger installed on the ground, and heat exchange for cooling the coolant of the submerged pump. It is roughly divided into a water-sealing type in which the vessel is provided in the submerged motor pump itself.

  As a water-sealed submerged motor pump, a configuration in which a heat exchanger is further arranged outside the submerged motor is known. A configuration in which a heat exchanger is arranged in series with respect to a pump and a submerged motor is known. For example, in Patent Document 1, a helical heat transfer tube through which the coolant of a submerged motor passes inside is arranged on the discharge port side of the pump unit, and the pumped liquid is used as a secondary coolant. A submerged motor pump is disclosed.

  On the other hand, the power cable for supplying power to the submerged motor in this type of submerged motor pump is generally a very long one that is connected directly to the submerged motor at the lower end side and a connection box arranged on the ground at the upper end side. Is.

JP 2002-130191 A

  However, in a configuration in which a heat exchanger is further provided outside the submerged motor, a pipe for introducing the primary coolant from the submerged motor to the heat transfer pipe of the heat exchanger is required. The diameter increases. Therefore, it cannot be used in a protective tube with a small inner diameter. Moreover, in the structure which has arrange | positioned the heat exchanger in series with respect to the pump and the motor, the length of the whole liquid motor pump becomes long and it enlarges. Furthermore, if the power cable is a single long piece directly connected to the submerged motor as described above, it is necessary to always transport the power cable together with the submerged motor pump, and the submerged motor is equivalent to the weight of the cable. Since the weight of the pump becomes heavy, handling and transportation are complicated.

  An object of the present invention is to solve the problems in the conventional water-sealed submersible motor pump, and to provide a water-sealed submersible motor pump having a small outer diameter and a short overall length. Another object of the present invention is to improve the handleability and transportability of the submerged motor pump.

  The present invention is a pump unit, a submerged motor for driving the pump unit arranged in series with the pump unit, a primary coolant sealed in the submerged motor, and a pumped liquid of the pump unit. A submerged motor pump comprising a heat exchanger for exchanging heat with a secondary coolant, wherein the heat exchanger is integrated with an outer periphery of the submerged motor. Provide a pump.

  By making the heat exchanger integral with the outer periphery of the submerged motor, piping for guiding the primary coolant to the heat exchanger can be omitted, and the outer diameter of the submerged motor can be reduced. As a result, the submerged motor pump of the present invention can be used by being inserted into a protective tube having a smaller inner diameter. Further, since the heat exchanger is not arranged in series with the pump unit or the submerged motor, the length of the submerged motor pump as a whole can be reduced. Furthermore, there is no need to install a heat exchanger on the ground.

  Specifically, the heat exchanger is formed between an outer peripheral frame of the submerged motor and a cover surrounding the outer peripheral frame, and a heat exchange chamber to which the pumped liquid is supplied from the pump unit, and the heat And a heat transfer tube that is piped to the exchange chamber and through which the primary coolant passes.

  By using the outer peripheral frame of the submerged motor as a part of the heat exchanger, the outer diameter of the submerged motor can be effectively reduced.

  More specifically, the submersible motor pump includes a secondary coolant inlet pipe that connects the discharge side of the pump unit and the inlet of the heat exchange chamber, the outlet of the heat exchanger chamber, and the suction of the pump unit. A secondary coolant outlet pipe connecting the sides. The submerged motor rotates in conjunction with the rotation of the primary cooling liquid inlet communicating with one end of the heat transfer tube, the primary cooling liquid outlet communicating with the other end of the heat transfer tube, and the drive shaft of the submerged motor. And a rotating body that circulates the primary coolant between the heat transfer tube, the primary coolant inlet, and the primary coolant outlet. The rotating body is, for example, a thrust collar provided on the motor shaft. The rotating body may be an impeller fixed to the motor shaft.

  It is preferable to further include a watertight connector comprising a receptacle electrically connected to the motor unit, and a plug provided in a power cable for supplying power to the motor unit and fitted into the receptacle. Since the power cable can be separated from the submerged motor pump by this connector, handling and transportability are improved.

  In the submerged motor pump of the present invention, since the heat exchanger has an integral structure with the outer periphery of the submerged motor, the outer diameter of the motor unit can be reduced and can be used by being disposed in a protective tube having a smaller inner diameter. Further, since the heat exchanger is not arranged in series with the pump unit or the motor unit, the overall length of the submerged motor pump can be reduced. Furthermore, there is no need to install a heat exchanger on the ground. Furthermore, by providing a connector consisting of a receptacle electrically connected to the submerged motor and a plug provided on the power cable for power supply, the power cable can be easily attached to and detached from the submerged motor pump. Handleability and transportability are greatly improved.

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

  FIG. 1 to FIG. 2B show a water-sealed high-in-water submersible motor pump 1 according to an embodiment of the present invention. As shown in FIG. 3, the submerged motor pump 1 is disposed in a straight tubular protective tube 3 having openings at both ends extending from the ground surface to an underground tank 2 provided in the ground. A pumping pipe 4 is connected to the upper end of the submerged motor pump 1, and the upper end of the pumping pipe 4 extending to the ground surface through the protective pipe 3 is connected to a downstream pipe 5.

  The submerged motor pump 1 includes a pump unit 11 and a submerged motor 12 for driving the pump unit 11. The submerged motor 12 is arranged in series below the pump unit 11. Moreover, the outer diameter of the pump part 11 and the submerged motor 12 is set smaller than the inner diameter of the protective tube 3, and the submerged motor pump 1 as a whole has an elongated shape. The primary coolant is sealed inside the submerged motor 12. As will be described in detail later, the submerged motor pump 1 includes a heat exchanger 13 that is integrated with the outer periphery of the submerged motor 12, and the primary coolant is the pumped liquid of the pump unit 11 in the heat exchanger 13. It is cooled by heat exchange with the secondary coolant.

  Next, the pump unit 11 will be described. As most clearly shown in FIG. 2A, the pump unit 11 in this embodiment includes five-stage pumps 16 </ b> A to 16 </ b> E having a common pump shaft 15. Each pump 16 </ b> A to 16 </ b> E includes a pump casing 17, a sliding bearing 18 of the pump shaft 15, and an impeller 19 fixed to the pump shaft 15. The pump casings 17 of the five-stage pumps 16 </ b> A to 16 </ b> E are connected in series so that the suction side is the lower side and the discharge side is the upper side. A connection casing 21 is connected to the suction side of the pump casing 17 of the pump 16A in the first stage (the lowermost side in the drawing), and the connection casing 21 is provided with a suction port 21a. On the other hand, a check valve casing 23 is connected to the discharge side of the pump casing 17 of the pump 16E at the fifth stage (the uppermost side in the drawing) via an intermediate casing 22. In the check valve casing 23, a check valve 24 which is a spring type in this embodiment is accommodated. The check valve casing 23 is connected to the lower end side of the water pumping pipe 4. The liquid (for example, liquefied natural gas) in the underground tank 2 sucked from the suction port 21 a is sequentially pressurized by the five-stage pumps 16 </ b> A to 16 </ b> E, and then passed through the intermediate casing 22 and the check valve casing 23. It is discharged to the pumping pipe 4 and sent to the downstream pipe 5 arranged on the ground surface through the pumping pipe 4.

  Next, the submerged motor 12 will be described with further reference to FIGS. As shown most clearly in FIG. 2B, the submerged motor 12 includes a cylindrical outer peripheral frame 26 having upper and lower ends opened. A motor shaft 28 to which a rotor 27 is fixed is accommodated in the outer peripheral frame 26. A stator 29 is fixed to the inner surface of the outer peripheral frame 26 so as to face the rotor 27. A stator winding 31 is wound around the stator 29. A cylindrical frame cover 32 whose upper and lower ends are open is attached to the outside of the outer peripheral frame 26.

  An opening on the upper end side of the outer peripheral frame 26 is sealed with an upper bearing bracket 34, and a seal casing 35 is fixed thereon. The upper end of the motor shaft 28 that penetrates the upper bearing bracket 34 and protrudes into the seal casing 35 is connected to the lower end of the pump shaft 15 by a sleeve coupling 36. Further, the motor shaft 28 is sealed at the seal casing 35. In the present embodiment, the shaft seal device is a tandem type considering the prevention of adhesion of deposits such as calcium carbonate that may be deposited in the liquid in the underground tank 2 and the vertical movement of the motor shaft 28 and the pump shaft 15. The mechanical seal 37 is adopted. Further, the seal casing 35 includes a pressure adjusting device 38.

  On the other hand, the opening on the lower end side of the outer peripheral frame 26 is sealed with an end plate 41. A lower bearing bracket 44 including a lower part 42 and an upper part 43 is disposed inside the outer peripheral frame 26 near the end plate 41. A lower part 42 is fixed above the end plate 41 with a space therebetween, and an upper part 43 is fixed thereon.

  Here, the bearing structure of the motor shaft 28 will be described. An upper radial bearing 46 and a lower radial bearing 47 made of slide bearings are attached to the upper bearing bracket 34 and the lower bearing bracket 44, respectively. The radial load of the motor shaft 28 is supported by the upper radial bearing 46 and the lower radial bearing 47. A thrust collar 48 is provided in the vicinity of the lower end of the motor shaft 28. The lower part 42 and the upper part 43 of the lower bearing bracket 44 correspond to upper and lower surfaces of the thrust collar 48, respectively. A lower thrust bearing 49 and an upper thrust bearing 50 are attached. The thrust load of the motor shaft 28 is supported by the lower thrust bearing 49 and the upper thrust bearing 50.

  Next, the cooling method of the submerged motor 12 will be described. The interior of the submerged motor 12, that is, the space sealed by the outer peripheral frame 26, the upper bearing bracket 34, the mechanical seal 37, and the end plate 41 is filled with the primary coolant. Hereinafter, the heat exchanger 13 for cooling the primary coolant will be described.

  The outer peripheral frame 26 includes an upper flange-like portion 26a and a lower flange-like portion 26b that protrude outward, and the upper end side and the lower end side of the frame cover 32 are located on the upper flange-like portion 26a and the lower flange-like portion 26b. It is fixed. The frame cover 32 surrounds the outer peripheral frame 26 with a space therebetween, and constitutes a heat exchange chamber 51 in which a cylindrical space formed between the outer surface of the outer peripheral frame 26 and the inner surface of the frame cover 32 is sealed. . As will be described in detail later, a pumped liquid that functions as a secondary coolant is supplied into the heat exchange chamber 51. Further, in the heat exchange chamber 51, one heat transfer tube 52 through which the primary coolant passes is provided. Specifically, the heat transfer tube 52 is provided in a spiral shape so as to surround the periphery of the outer peripheral frame 26. As shown in FIGS. 2B and 6, a spacer 53 is interposed between the heat transfer tube 52 and the outer peripheral frame 26.

  In order to circulate the primary coolant, the thrust collar 48 has a function as an impeller. Referring to FIG. 5, the thrust collar 48 is formed with an axial flow path 48a extending from the lower end and a radial flow path 48b extending radially from the axial flow path 48a. The axial flow path 48 a opens in a space between the end plate 41 and the lower part 42 of the lower bearing bracket 44. On the other hand, the radial flow path 48 b opens in an annular space formed by the outer periphery of the thrust collar 48 and the lower part 42 and the upper part 43 of the lower bearing bracket 44.

  As most clearly shown in FIG. 5, the lower flange-like portion 26 b of the outer peripheral frame 26 has an inside of the submerged motor 12 (a space between the aforementioned end plate 41 and the lower part 42 of the lower bearing bracket 44). A primary coolant inlet 26c communicating with the primary coolant inlet 26c is formed, and a lower end 52a of the heat transfer tube 52 is connected to the primary coolant inlet 26c. Further, the upper part 43 of the lower bearing bracket 44 includes an annular space formed by the outer periphery of the thrust collar 48 and the lower part 42 and the upper part 43 of the lower bearing bracket 44, the rotor 27 and the stator 29. A flow path 43a is formed to communicate with the space in which the water is accommodated. Accordingly, as indicated by a two-dot chain line L1 in FIG. 5, the primary coolant flowing in from the primary coolant inlet 26c reaches the space in which the rotor 2 and the stator 29 are accommodated via the thrust collar 48.

  On the other hand, as shown most clearly in FIG. 4A, on the upper end side of the outer peripheral frame 26, a primary coolant outlet 35a communicating with the inside of the submerged motor 12 is formed in the lower portion of the seal casing 35. The liquid outlet 35 a is connected to the upper end 52 b of the heat transfer tube 52. Further, the upper bearing bracket 34 is formed with a flow path 34a for communicating the space in which the rotor 27 and the stator 29 are accommodated with the primary coolant outlet 35a side. Therefore, as indicated by a two-dot chain line L2 in FIG. 4A, the primary coolant flows from the space in which the rotor 27 and the stator 29 are accommodated toward the primary coolant outlet 35a. The primary coolant outlet 35a is also connected to a head tank 54 provided on the ground surface.

  Next, the flow path of the secondary coolant (pumped liquid of the pump unit 11) in the heat exchanger 13 will be described. First, a secondary coolant inlet pipe 56 extending in the vertical direction is provided, the upper end of which is connected to the discharge side of the second stage pump 16B of the pump unit 11 and the lower end of which is connected to the inlet of the heat exchange chamber 51. . As most clearly shown in FIG. 5, the inlet of the heat exchange chamber 51 is composed of end plates 41 and flow paths 41 a and 26 d formed below the lower flange-like portion 26 b of the outer peripheral frame 26. As shown by a one-dot chain line L3 in FIG. 5, a part of the pumped liquid discharged from the second-stage pump 16B flows into the heat exchange chamber 51 through the secondary coolant inlet pipe 56.

  Further, a secondary coolant outlet pipe 57 extending in the vertical direction is provided in which the lower end is connected to the outlet of the heat exchange chamber 51 and the upper end is connected to the discharge side of the first stage pump 16A of the pump unit 11. . As shown most clearly in FIG. 4B, the outlet of the heat exchange chamber 51 is composed of the upper flange-like portion 26 a of the outer peripheral frame 26, the upper bearing bracket 34, and the flow paths 26 e, 34 b, 35 b in which the seal casing 35 is formed. 4B, the secondary coolant that has flowed out from the outlet of the heat exchange chamber 51 flows through the secondary coolant outlet pipe 57 toward the discharge side of the first-stage pump 16A.

  2A and 2B, when the pumps 16A to 16E of the pump unit 11 are driven by the submerged motor 12, the primary coolant circulates along a path indicated by a two-dot chain line L5 due to the impeller effect of the thrust collar 48. . Specifically, the primary coolant pressurized by the impeller effect passes through the lower bearing bracket 44, the lower radial bearing 47, the stator winding 31, and the upper radial bearing 46 from the primary coolant outlet 35 a to the heat exchange chamber. It flows into the heat transfer pipe 52 piped in 51. The primary cooling water is cooled by heat exchange with the secondary cooling liquid in the heat exchange chamber 51 when passing through the heat transfer tube 52. The cooled primary cooling water flows from the primary coolant inlet 26 c into the outer peripheral frame 26 and returns to the thrust collar 48. On the other hand, the secondary coolant flows along a path indicated by a one-dot chain line L6. Specifically, the secondary coolant that has flowed into the secondary coolant inlet pipe 56 from the discharge side of the second-stage pump 16 </ b> B flows into the lower portion of the heat exchange chamber 51 through the secondary coolant inlet pipe 56. Then, heat exchange is performed with the primary coolant flowing through the heat transfer tube 52. The secondary coolant that has flowed into the secondary coolant outlet pipe 57 from the upper part of the heat exchange chamber 51 passes through the secondary coolant outlet pipe 57 and returns to the discharge side of the first-stage pump 16A. The secondary cooling liquid is returned to the discharge side of the first-stage pump 16A and pressurized to some extent, so that vaporization due to temperature rise can be achieved even when the secondary cooling liquid (lifted liquid) is a liquid with a low saturated vapor pressure. Can be prevented.

  As described above, in the submerged motor pump 1 of the present embodiment, the heat exchanger 13 is integrated with the outer periphery of the submerged motor 12, so that piping for guiding the primary coolant to the heat exchanger 13 is omitted. The outer diameter of the submerged motor 12 can be reduced. As a result, the submerged motor pump 1 of the present embodiment can be used by being inserted into the protective tube 3 having a smaller inner diameter. Further, since the heat exchanger 13 is not arranged in series with the pump unit 11 and the submerged motor 12, the length of the submerged motor pump 1 as a whole can be reduced. Furthermore, there is no need to install a heat exchanger on the ground.

  Next, a method for supplying power to the submerged motor 12 will be described. As shown in FIGS. 1, 2A, and 6, in order to supply power to the submerged motor 12 from the power cable 64, a plurality of watertight connectors 61 (three in this embodiment) are submerged. 1 is provided. This connector 61 is provided on a receptacle 62 electrically connected to the stator winding 31 of the submerged motor 12 and a power cable 64 extending through a protective tube (see FIG. 3) to the power supply on the ground side or to the power system. And a plug 63 into which the receptacle 62 is fitted. Since the power cable 64 can be separated from the submerged motor pump 1 by this connector, handling and transportability are improved.

  Referring to FIG. 8, the receptacle 62 (submerged motor 12 side) of the connector 61 includes a male contact 67 and a pin insulator 68 in the shell 66. On the other hand, the plug 63 of the connector 61 (power cable 64 side) includes a female contact 71 and a socket insulator 72 electrically connected to the power cable 64 in the end bells 69 and 70. The female connector 61 and the socket insulator 72 protrude from the end of the end bell 69. Further, the end bell 69 is provided with a coupling nut 73 at the tip. When the plug 63 is inserted into the receptacle 62, the male contact 67 is inserted into the female contact 71, the submerged motor 12 side and the power cable 64 side are electrically connected, and the pin insulator 68 is inserted into the socket insulator 72. . After the coupling of the receptacle 62 and the plug 63 is completed, the coupling nut 73 is screwed into the shell 68 of the receptacle 62, and the plug 63 is filled with resin.

  The power cable 64 is provided with a corrugated metal sheath 76 made of stainless steel or the like in consideration of permeability, water immersion, and corrosivity. By adopting this corrugated metal sheath 76, it is possible to ensure good flexibility while preventing intrusion of liquefied natural gas, seawater or the like into the power cable. Further, by providing a special polyethylene layer 77 outside the power cable 64, it can be directly installed in liquefied natural gas, seawater, or the like.

The longitudinal cross-sectional view which shows the submersible motor pump which concerns on embodiment of this invention. The longitudinal cross-sectional view which shows the upper part of the submerged motor pump which concerns on embodiment of this invention. The longitudinal cross-sectional view which shows the lower part of the submersible motor pump which concerns on embodiment of this invention. The longitudinal cross-sectional view which shows the installation state of the submersible motor pump which concerns on embodiment of this invention. FIG. 4 is a partial enlarged view of a portion IV (an outlet portion of the primary coolant from the submerged motor) in FIG. The elements on larger scale of the part IV (inlet part to the heat exchanger of a secondary coolant) of FIG. The longitudinal cross-sectional view of the part V of FIG. The expanded sectional view in the VI-VI line of FIG. 2A. The expanded sectional view in the VII-VII line of FIG. 2B. The partial cross section front view which shows a connector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Submersible motor pump 2 Underground tank 3 Protection pipe 4 Pumping pipe 5 Piping 11 Pump part 12 Submerged motor 13 Heat exchanger 15 Pump shaft 16A-16E Pump 17 Pump casing 18 Slide bearing 19 Impeller 21 Connection casing 21a Suction port 22 Intermediate casing 23 Check valve casing 24 Check valve 26 Outer frame 26a Upper flange-like portion 26b Lower flange-like portion 26c Primary coolant inlet 26d, 26e Flow path 27 Rotor 28 Motor shaft 29 Stator 31 Stator winding 32 Frame cover 34 Upper bearing bracket 34a, 34b Flow path 35 Seal casing 35a Primary coolant outlet 35b Flow path 36 Sleeve coupling 37 Mechanical seal 38 Pressure adjusting device 41 End plate 41a Flow path 42 Lower part 43 Upper part 43a Road 44 Lower bearing bracket 46 Upper radial bearing 47 Lower radial bearing 48 Thrust collar 48a Axial flow path 48b Radial flow path 49 Lower thrust bearing 50 Upper thrust bearing 51 Heat exchange chamber 52 Heat transfer tube 52a Lower end 52b Upper end 53 Spacer 54 Head tank 56 Secondary coolant inlet pipe 57 Secondary coolant outlet pipe 61 Connector 62 Receptacle 63 Plug 64 Power cable 66 Shell 67 Male contact 68 Pin insulator 69, 70 End bell 71 Female contact 72 Socket insulator 73 Coupling nut 76 With wave Metal exterior 77 Special polyethylene layer

Claims (4)

A pump unit, a submerged motor for driving the pump unit disposed in series with the pump unit, a primary coolant sealed in the submerged motor, and a secondary coolant that is a pumped liquid of the pump unit In a submerged motor pump comprising a heat exchanger for performing heat exchange with
The submersible motor pump, wherein the heat exchanger has an integral structure with an outer periphery of the submerged motor. The heat exchanger is
A heat exchange chamber formed between an outer peripheral frame of the submerged motor and a cover surrounding the outer peripheral frame, to which the pumped liquid is supplied from the pump unit;
The submerged motor pump according to claim 1, further comprising: a heat transfer pipe that is piped to the heat exchange chamber and through which the primary coolant passes. A secondary coolant inlet pipe connecting the discharge side of the pump unit and the inlet of the heat exchange chamber;
A secondary coolant outlet pipe connecting the outlet of the heat exchange chamber and the suction side of the pump unit;
The submerged motor is
A primary coolant inlet communicating with one end of the heat transfer tube;
A primary coolant outlet communicating with the other end of the heat transfer tube;
A rotating body that rotates in conjunction with rotation of a drive shaft of a submerged motor and circulates the primary coolant between a heat transfer tube, a primary coolant inlet, and a primary coolant outlet, The submerged motor pump according to claim 2.   The watertight structure connector further comprising: a receptacle electrically connected to the motor unit; and a plug provided in a power cable for supplying power to the motor unit and fitted into the receptacle. 4. The submerged motor pump according to any one of 3 above.

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