JP7294942B2 - oil drilling pump - Google Patents

Description

The present disclosure relates to crude oil drilling pumps.

A pump called ESP (Electrical Submersible Pump) has been widely used as a device for pumping up crude oil from an oil well. As shown in Patent Document 1 below, a pump includes a rotating shaft that rotates around the rotating shaft, a plurality of impellers that are integrally provided with the rotating shaft, and a casing that covers the rotating shaft and the impellers from the outer peripheral side. I have it. This pump is placed in a pipe inserted into a well (oil field), and a rotating shaft is rotated by an electric motor to pump underground oil upwards.

In recent years, a pump using a canned motor as an electric motor has been proposed for the purpose of improving maintainability and making the apparatus compact. This type of pump includes a production pipe inserted into an oil well, a motor rotor arranged inside the production pipe, a motor stator integrally provided on the inner peripheral side of the production pipe, and a motor stator integrally provided above the motor rotor. a pump rotor covered by the pump rotor, a pump stator that covers the pump rotor from the outer peripheral side and forms a flow path through which the crude oil flows, and a thrust bearing that rotatably supports the pump rotor with respect to the production pipe. . The motor stator has a coil, and a magnet is provided on the outer peripheral surface of the motor rotor facing the coil. By energizing the coil, the motor rotor and the pump rotor are rotated by electromagnetic force. This causes crude oil to be sucked up from the lower end of the pump.

Japanese Patent Publication No. 2018-508701

By the way, in the pump as described above, the thrust bearing is unavoidably exposed to crude oil. Since slurry is mixed in crude oil, if the slurry flows into the thrust bearing, the wear of the sliding contact parts will be accelerated. As a result, the stable operation of the pump may be hindered.

The present disclosure has been made to solve the above problems, and an object thereof is to provide a crude oil drilling pump that can be operated more stably.

In order to solve the above problems, a crude oil drilling pump according to the present disclosure includes a production pipe having a tubular shape along an axis extending in the vertical direction, a pump rotor extending in the production pipe in the axial direction, the production pipe and the a pump stator enclosing the pump rotor between itself and the pump rotor, the pump rotor comprising a plurality of pump shafts sequentially connected in the axial direction, and a plurality of stages provided on each of the pump shafts; It has an impeller that rotates with the pump shaft to pump crude oil upward, and a thrust collar that is provided on each of the pump shafts and protrudes radially outward, and the pump stator extends along the axis. It has a cylindrical stator body, and a thrust pad that protrudes radially inward of the axis from the inner peripheral surface of the stator body and supports the thrust collar slidably from below in the circumferential direction.

According to the present disclosure, it is possible to provide a crude oil drilling pump that can be operated more stably.

1 is a vertical cross-sectional view showing the configuration of a crude oil drilling pump according to an embodiment of the present disclosure; FIG. FIG. 4 is a diagram showing a configuration of a connection portion of a pump shaft according to an embodiment of the present disclosure; FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; 1 is a diagram showing the configuration of a thrust bearing according to an embodiment of the present disclosure; FIG. It is a figure showing composition of an impeller concerning an embodiment of this indication.

Hereinafter, a crude oil drilling pump according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 5. FIG. A crude oil extraction pump 100 according to the present embodiment is a device for pumping up crude oil from an oil well. As shown in FIGS. 1 and 2, this crude oil drilling pump 100 includes a pump body P, a motor M, a drilling pipe 9, a lower end thrust bearing portion Bd, and an intermediate thrust bearing portion Bs. The pump main body P is driven by the power supplied from the motor M. The excavation pipe 9 covers the pump main body P, the motor M, the lower end thrust bearing portion Bd, and the intermediate thrust bearing portion Bs from the outer peripheral side, and has a tubular shape centered on an axis O extending in the vertical direction.

The pump main body P has a production pipe main body 1A, a pump rotor 21, and a pump stator 3. The production pipe main body 1A is a tubular member coaxial with the drilling pipe 9 and arranged on the inner peripheral side of the drilling pipe 9 . The pump rotor 21 includes a plurality of pump shafts 21S connected in the direction of the axis O, a coupling sleeve 30 (see FIG. 2) connecting the pump shafts 21S, and a plurality of impellers 5 fixed to the pump shafts 21S. ,have.

As shown in FIG. 2, a pair of pump shafts 21S adjacent to each other in the vertical direction (the direction of the axis O) face each other with a gap G therebetween. A cylindrical fitting member 41 is fitted to each shaft end. These fitting members 41 are covered with the coupling sleeve 30 from the outer peripheral side. The coupling sleeve 30 is a spline coupling that connects the fitting members 41 to each other by spline fitting, and has a plurality of key grooves extending in the direction of the axis O on its inner peripheral surface (sleeve inner peripheral surface 30i). are formed at intervals. A plurality of linear protrusions that engage with the key groove are formed on the outer peripheral surface of the fitting member 41 . As a result, the pair of adjacent pump shafts 21S can rotate about the axis O together. A gap between the fitting member 41 and the coupling sleeve 30 is covered with a cover member 40 from above.

As shown in FIG. 1, the pump stator 3 has a stator main body 3H that covers the impeller 5 from the outer peripheral side, and a stator extension portion 3E. The stator main body 3H repeats expansion and contraction in diameter from the bottom to the top, thereby accommodating the impeller 5 and defining the stator flow path Fs through which the crude oil flows. The configurations of the impeller 5 and the pump stator 3 will be described later. The stator extension 3E is integrally provided below the stator main body 3H and has a cylindrical shape centered on the axis O. As shown in FIG. A lower end thrust pad 7d, which will be described later, is attached to the lower end of the stator extension 3E.

As shown in FIG. 1, the motor M has a production pipe tip 1B, a motor rotor 22, a coil C, and a magnetic member 22M. The production pipe tip portion 1B has a cylindrical shape and is integrally provided below the production pipe main body 1A. The production pipe body 1A and the production pipe tip 1B form the production pipe 1 as a whole. A plurality of coils C arranged in the circumferential direction are provided on the inner peripheral surface of the production pipe distal end portion 1B. This coil C generates an electromagnetic force by a current supplied from the outside. The motor rotor 22 is arranged inside the coils C and has a columnar shape extending along the axis O. As shown in FIG. The motor rotor 22 is connected to the lowermost pump shaft 21S of the plurality of pump shafts 21S forming the pump rotor 21 via a lower end spline coupling 30d. The plurality of pump shafts 21S and the motor rotor 22 form the rotor 2 as a whole. A permanent magnet as a magnetic member 22M is provided on the outer peripheral surface of the motor rotor 22 . Rotational force is applied to the rotor 2 by an electromagnetic force generated between the magnetic field generated by energizing the coil C and the magnetic field of the magnetic member 22M.

The leading end portion 1B of the production pipe is supported from below by an annular support portion 4 projecting radially inwardly from the inner peripheral surface of the excavation pipe 9. As shown in FIG. An opening on the inner peripheral side of the support portion 4 is an opening H for taking in the crude oil. The lower end of the motor rotor 22 is inserted through this opening H. Inside the motor rotor 22, in addition to the opening H, a suction passage Fi for sucking crude oil is formed. This suction flow path Fi communicates with a stator flow path Fs formed on the inner peripheral side of the pump stator 3 .

Further, on the outer peripheral surface of the motor rotor 22 and above the magnetic member 22M, an annular lower end thrust collar 6d projecting radially outward and centered on the axis O is provided. The bottom thrust collar 6d is supported from above and below by bottom thrust pads 7d provided on the inner peripheral surface of the pump stator 3 (stator extension 3E). These lower end thrust collar 6d and lower end thrust pad 7d form a lower end thrust bearing portion Bd. The rotor 2 (pump rotor 21 and motor rotor 22) is rotatably supported around the axis O with respect to the pump stator 3 by the lower end thrust bearing portion Bd and an intermediate thrust bearing portion Bs, which will be described later.

Next, the configuration of the connecting portion of the pump shaft 21S and the configuration of the intermediate thrust bearing portion Bs will be described with reference to FIGS. 2 and 3. FIG. As shown in FIG. 2, the shaft ends of a pair of adjacent pump shafts 21S are opposed to each other with a gap G extending in the vertical direction, and are covered by the coupling sleeve 30 via the fitting member 41 from the outer peripheral side thereof. ing. A through hole 80 is formed in the coupling sleeve 30 to communicate the gap G with the stator flow path Fs on the outer peripheral side. More specifically, as shown in FIG. 3, the coupling sleeve 30 has a through hole 80 formed in the circumferential direction. The through-hole 80 extends rearward in the rotational direction R of the rotor 2 from the radially inner end (outlet 80b) to the radially outer end (inlet 80a). Further, the inlet 80a is provided with a capture section 81 for capturing slurry contained in the crude oil. A mesh made of metal is preferably used as the trapping portion 81 . The trapping section 81 regulates the passage of the slurry, while allowing the liquid phase components of the crude oil to pass through, excluding the slurry.

Furthermore, as shown in FIG. 2, an intermediate thrust bearing portion Bs is provided below the coupling sleeve 30 . One intermediate thrust bearing portion Bs is provided for each pump shaft 21S. The intermediate thrust bearing portion Bs includes an intermediate thrust collar 6 (thrust collar) provided on the outer peripheral surface of the pump shaft 21S (shaft outer peripheral surface 21o), and an intermediate thrust pad 7 (thrust pad) fixed to the pump stator 3. ,have.

The intermediate thrust collar 6 protrudes radially outward from the outer peripheral surface 21o of the shaft, and includes a thrust collar body 6H having an annular shape centered on the axis O, and a second thrust collar body 6H provided on the outer peripheral end face of the thrust collar body 6H. It has two convex portions 61 . The second protrusion 61 protrudes radially outward from the outer peripheral surface of the thrust collar main body 6H, thereby forming an annular shape centered on the axis O. As shown in FIG. The dimension of the second convex portion 61 in the direction of the axis O is smaller than the dimension in the direction of the axis O of the thrust collar main body 6H.

The intermediate thrust pad 7 is fixed to the upper end of the pump stator 3 (stator main body 3H). The surface of the intermediate thrust pad 7 facing upward is a sliding surface Sc that slides on the thrust collar main body 6H. The pump stator 3 is provided with a first protrusion 31 that protrudes upward so as to cover the sliding surface Sc from the outer peripheral side (see FIG. 2 or FIG. 4). That is, the dimension of the first convex portion 31 in the direction of the axis O is set larger than the dimension of the intermediate thrust pad 7 in the direction of the axis O. As shown in FIG. Furthermore, the upper end of the first protrusion 31 faces the above-described second protrusion 61 from below. A slight gap is formed in the axis O direction between the first protrusion 31 and the second protrusion 61 . Furthermore, a slight radially expanding gap is formed between the first convex portion 31 and the thrust collar main body 6H.

Next, the configuration of the impeller 5 will be described with reference to FIG. The impeller 5 has a disk 51 , blades 52 and a shroud cover 53 . The disk 51 is fixed to the outer peripheral surface of the pump shaft 21S and has a disc shape centered on the axis O. As shown in FIG. The downward facing surface of the disk 51 is a disk main surface 51M. The disk main surface 51M is curved from the inner side to the outer side in the radial direction from the lower side to the upper side.

A plurality of blades 52 arranged at intervals in the circumferential direction are provided on the disk main surface 51M. Although not shown in detail, each blade 52 is curved forward in the rotational direction of the rotor 2 from the radially inner side to the outer side. Also, the blade height of the blade 52 (rising dimension from the disk main surface 51M) gradually decreases from the bottom to the top.

The upward facing surface (disk back surface 51B) of the disk 51 extends in a planar shape from the inner side to the outer side in the radial direction from the bottom to the top. A swirl vane Ws and a partition 90 are provided in order from the radially outer side to the inner side on the disk back surface 51B. A plurality of swirl vanes Ws are provided at intervals in the circumferential direction. Each swirl vane Ws has a plate shape extending in the radial direction. The partition portion 90 protrudes upward from the disk back surface 51B radially inside the swirl vanes Ws. The partition part 90 has a cylindrical shape centered on the axis O. As shown in FIG. A space is formed radially inward of the partition portion 90 . Further, the disk 51 is formed with a balance hole Bh penetrating the disk 51 in the direction of the axis O from the disk main surface 51M to the disk rear surface 51B.

The shroud cover 53 has a funnel shape covering the plurality of blades 52 from below. The shroud cover 53 is curved from the inner side to the outer side in the radial direction from the bottom to the top.

The impeller 5 configured as described above is covered with the stator main body 3H from the outer peripheral side. A surface of the inner peripheral surface of the stator main body 3H that faces the shroud cover 53 is a facing surface P1. A first stepped portion D1 that covers the lower end of the shroud cover 53 in the direction of the axis O and in the radial direction is formed in the lower portion of the facing surface P1. A portion of the shroud cover 53 facing the first step portion D1 is a first seal portion S1. Furthermore, a baffle plate B is provided in a portion above the first stepped portion D1 on the facing surface P1. The baffle plate B has a plate shape that protrudes radially inward from the facing surface P1 and extends in the radial direction. A plurality of baffle plates B are provided at intervals in the circumferential direction.

Of the inner peripheral surface of the stator main body 3H, a region above and adjacent to the facing surface P1 is a connection surface P2. The connection surface P2 is concave in a curved shape toward the radially outer side. Further, a region above and adjacent to the connection surface P2 is a downstream surface P3. The downstream surface P3 extends from the radially outer side to the inner side in an upward direction. A plurality of vanes V and a stator shroud 3S fixed to the inner peripheral side of the vanes V are provided on the downstream surface P3. Each vane V has a plate shape protruding radially inward from the downstream surface P3. A plurality of vanes V are arranged at intervals in the circumferential direction.

The stator shroud 3S faces the disk back surface 51B from above. A downward facing surface (stator shroud lower surface 3B) of the stator shroud 3S is provided with a projecting portion Pt and a second stepped portion D2 in order from the radially outer side toward the inner side. The projecting portion Pt protrudes downward so as to cover the radially outer edge of the disc 51 from the radially outer side with a gap therebetween. The second step portion D2 covers the partition portion 90 provided on the disk back surface 51B from the radially outer side. That is, the portion of the stator shroud lower surface 3B radially inner than the second stepped portion D2 recedes upward from the radially outer portion. A second seal portion S2 is formed by the second step portion D2 and the partition portion 90 .

Here, the area of the shroud cover 53 radially outside the first seal portion S1 is defined as a first area A1. A second area A2 is defined as a radially outer area of the disk back surface 51B relative to the second seal portion S2. The dimensions of each part are set so that the area (projected area) of the first area A1 is larger than the area (projected area) of the second area A2 when viewed from the direction of the axis O.

(Effect)
Next, the operation of the crude oil extraction pump 100 will be described. In order to operate the crude oil drilling pump 100, the rotor 2 is rotated by supplying electric power to the motor M described above. When the rotor 2 rotates, the crude oil in the oil well is sucked up by the pump main body P from the opening H formed at the lower end of the drilling pipe 9 . At this time, the crude oil is also sucked up by the suction passage Fi formed in the motor rotor 22 .

Here, in the crude oil drilling pump 100 described above, the thrust bearings (lower end thrust bearing portion Bd, middle thrust bearing portion Bs) are exposed in the stator flow path Fs, and are therefore exposed to the crude oil flowing through the flow path. state. Since crude oil contains slurry, if the slurry flows into the thrust bearing, the wear of the sliding surface Sc will be accelerated. As a result, the stable operation of the crude oil drilling pump 100 may be hindered. Therefore, the present embodiment adopts the configuration as described above.

According to the above configuration, the pump rotor 21 is formed by connecting the plurality of pump shafts 21S, and the thrust collar 6 is provided on each pump shaft 21S. Further, the pump stator 3 is provided with a plurality of thrust pads 7 that support each thrust collar 6 from below. Therefore, compared to a configuration in which only one thrust collar 6 and one thrust pad 7 are provided in the rotor 2, the load applied to each thrust collar 6 and thrust pad 7 is dispersed, and one of the intermediate thrust bearing portions Bs The load per hit can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be reduced.

According to the above configuration, the first convex portion 31 covers the sliding surface Sc between the thrust collar 6 and the thrust pad 7 from the outer peripheral side. Furthermore, the first protrusion 31 is covered with a second protrusion 61 facing from above. Therefore, the sliding surface Sc is less likely to be directly exposed to crude oil flowing on the inner peripheral side of the pump stator 3 . As a result, the possibility of slurry contained in the crude oil flowing into the sliding surface Sc is reduced, and wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

According to the above configuration, the area of the first region A1 radially outside the first seal portion S1 in the shroud cover 53 positioned downward (upstream side) when viewed in the direction of the axis O is positioned upward (downstream side). It is larger than the area of the second region A2 on the radially outer side of the second seal portion S2 on the disk back surface 51B. As a result, a load is applied to the impeller 5 in an upward direction. Therefore, the thrust load (the load directed from above to below) to be borne by each thrust collar 6 and each thrust pad 7 can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

According to the above configuration, since the baffle plate B is provided on the facing surface P1, the flow velocity of the fluid flowing along the facing surface P1 decreases. This increases the static pressure of the fluid on the shroud cover 53 side (that is, on the upstream side). Furthermore, since the swirl vane Ws is provided on the disk rear surface 51B, the flow velocity of the fluid flowing along the disk rear surface 51B increases. This reduces the static pressure of the fluid on the disk back surface 51B side (that is, downstream side). As a result, the impeller 5 is subjected to a force directed from the upstream side to the downstream side (that is, from the bottom to the top). Therefore, the thrust load (the load directed from above to below) to be borne by each thrust collar 6 and each thrust pad 7 can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

According to the above configuration, the gap G is formed between the adjacent pump shafts 21S. Some components of the crude oil flow into this gap G through the through holes 80, so that an intermediate pressure can be ensured. On the other hand, the slurry contained in the crude oil is captured by the capturing portion 81 and therefore does not flow into the gap G described above. That is, slurry can be prevented from flowing into between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) through the gap G. As a result, the possibility of wear occurring between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) can be reduced.

According to the above configuration, the gap between the fitting member 41 and the coupling sleeve 30 is covered with the cover member 40 from above. Therefore, it is possible to reduce the possibility of slurry flowing into the gap. As a result, the possibility of wear occurring between the coupling sleeve 30 and the fitting member 41 can be reduced.

According to the above configuration, the through hole 80 extends toward the rear side in the rotation direction R of the pump shaft 21S (that is, the side opposite to the rotation direction R) from the radially inner side toward the outer side. Therefore, it is possible to reduce the possibility of slurry flowing into the through hole 80 as the pump shaft 21S rotates. As a result, the possibility of wear occurring between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) can be reduced.

As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings, but the specific configuration is not limited to these embodiments, and design changes and the like are included within the scope of the present disclosure.
For example, the lower end thrust pad bearing portion Bd and the intermediate thrust bearing portion Bs described in the above embodiments specifically include parallel plane bearings, inclined plane bearings, tapered land bearings, step bearings, pocket bearings, spiral groove bearings, and It is possible to use a herringbone groove bearing that is appropriately selected according to the design and specifications.

<Appendix>
For example, the crude oil drilling pump described in each embodiment is understood as follows.

(1) A crude oil drilling pump 100 according to a first aspect includes a production pipe 1 having a tubular shape along an axis O extending in the vertical direction, a pump rotor 21 extending in the direction of the axis O within the production pipe 1, and a pump stator 3 surrounding the pump rotor 21 between the production pipe 1 and the pump rotor 21; the pump rotor 21 includes a plurality of pump shafts 21S sequentially connected in the direction of the axis O; The shafts 21S are each provided with a plurality of stages, and an impeller 5 that pumps crude oil upward by rotating together with the pump shaft 21S, and a thrust collar 6 that is provided on each of the pump shafts 21S and protrudes radially outward. The pump stator 3 includes a cylindrical stator body 3H extending along the axis O, and a thrust collar projecting radially inward of the axis O from the inner peripheral surface of the stator body 3H. and a thrust pad 7 that supports 6 from below so as to be slidable in the circumferential direction.

According to the above configuration, the pump rotor 21 is formed by connecting the plurality of pump shafts 21S, and the thrust collar 6 is provided on each pump shaft 21S. Further, the pump stator 3 is provided with a plurality of thrust pads 7 that support each thrust collar 6 from below. Therefore, compared to a configuration in which one thrust collar 6 and one thrust pad 7 are provided, for example, the load applied to each thrust collar 6 and thrust pad 7 can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be reduced.

(2) In the crude oil drilling pump 100 according to the second aspect, the pump stator 3 protrudes upward so as to cover the sliding surface Sc between the thrust collar 6 and the thrust pad 7 from the outer peripheral side. The thrust collar 6 has one convex portion 31, and the thrust collar 6 has a second convex portion 61 that protrudes radially outward and faces the upper end of the first convex portion 31 from below.

According to the above configuration, the first convex portion 31 covers the sliding surface Sc between the thrust collar 6 and the thrust pad 7 from the outer peripheral side. Furthermore, the first protrusion 31 is covered with a second protrusion 61 facing from above. Therefore, the sliding surface Sc is less likely to be directly exposed to crude oil flowing on the inner peripheral side of the pump stator 3 . As a result, the possibility of slurry contained in the crude oil flowing into the sliding surface Sc is reduced, and wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

(3) In the crude oil drilling pump 100 according to the third aspect, the impeller 5 includes a disk-shaped disk 51 fixed to the pump shaft 21S and a downward-facing surface of the disk 51 that is circumferentially spaced apart. and a shroud cover 53 that covers the blade 52 from below, and a first seal that forms a clearance between the outer peripheral surface of the shroud cover 53 and the pump stator 3 A second sealing portion S2 is formed to form a clearance between the pump stator 3 and the disk rear surface 51B of the disk 51 facing upward. is larger than the area of the second region A2 radially outward of the second seal portion S2 of the disk back surface 51B when viewed in the direction of the axis O. .

According to the above configuration, the area of the first region A1 radially outside the first seal portion S1 in the shroud cover 53 positioned downward (upstream side) when viewed in the direction of the axis O is positioned upward (downstream side). It is larger than the area of the second region A2 on the radially outer side of the second seal portion S2 on the disk back surface 51B. As a result, a load is applied to the impeller 5 in an upward direction. Therefore, the thrust load (load directed downward from above) that each thrust collar 6 and each thrust pad 7 should bear can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

(4) In the crude oil drilling pump 100 according to the fourth aspect, the pump stator 3 is circumferentially spaced from the facing surface P1, which is the portion facing the outer peripheral surface of the shroud cover 53 in the pump stator 3. A plurality of baffle plates B are provided and each extend in the radial direction, and the impeller 5 has swirl vanes Ws that are provided at intervals in the circumferential direction on the disk back surface 51B and each extend in the radial direction.

According to the above configuration, since the baffle plate B is provided on the facing surface P1, the flow velocity of the fluid flowing along the facing surface P1 decreases. This increases the static pressure of the fluid on the shroud cover 53 side (that is, on the upstream side). Furthermore, since the swirl vane Ws is provided on the disk rear surface 51B, the flow velocity of the fluid flowing along the disk rear surface 51B increases. This reduces the static pressure of the fluid on the disk back surface 51B side (that is, downstream side). As a result, the impeller 5 is subjected to a force directed from the upstream side to the downstream side (that is, from the bottom to the top). Therefore, the thrust load (the load directed from above to below) to be borne by each thrust collar 6 and each thrust pad 7 can be kept small. As a result, wear of the thrust collar 6 and the thrust pad 7 can be suppressed.

(5) In the crude oil drilling pump 100 according to the fifth aspect, the pair of pump shafts 21S that are vertically adjacent to each other are spaced apart from each other at the upper ends and the lower ends. through the coupling sleeve 30 radially through the coupling sleeve 30 and open to the gap G between the pair of pump shafts 21S. is formed, and a part of the through-hole 80 has a trapping portion 81 for trapping the slurry in the crude oil.

According to the above configuration, the gap G is formed between the adjacent pump shafts 21S. Some components of the crude oil flow into this gap G through the through holes 80, so that an intermediate pressure can be ensured. On the other hand, the slurry contained in the crude oil is captured by the capturing portion 81 and therefore does not flow into the gap G described above. That is, slurry can be prevented from flowing into between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) through the gap G. As a result, the possibility of wear occurring between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) can be reduced.

(6) The crude oil drilling pump 100 according to the sixth aspect further includes fitting members 41 fitted to the pair of pump shafts 21S, respectively, and the coupling sleeve 30 is provided between the pair of fitting members 41. The pair of pump shafts 21S are connected by being spline-fitted to each other, and the upper ends of the fitting member 41 and the coupling sleeve 30 are further provided with a cover member 40 that covers the gap therebetween.

According to the above configuration, the gap between the fitting member 41 and the coupling sleeve 30 is covered from above by the cover member 40, and leakage is prevented by a seal (not shown) such as an oil seal. Therefore, it is possible to reduce the possibility of slurry flowing into the gap. As a result, the possibility of wear occurring between the coupling sleeve 30 and the fitting member 41 can be reduced.

(7) In the crude oil drilling pump 100 according to the seventh aspect, the through hole 80 extends rearward in the rotational direction R of the pump shaft 21S from radially inward to outward.

According to the above configuration, the through hole 80 extends toward the rear side in the rotation direction R of the pump shaft 21S (that is, the side opposite to the rotation direction R) from the radially inner side toward the outer side. Therefore, it is possible to reduce the possibility of slurry flowing into the through hole 80 as the pump shaft 21S rotates. As a result, the possibility of wear occurring between the coupling sleeve 30 and the pump shaft 21S (fitting member 41) can be reduced.

100 Crude oil drilling pump 1 Production pipe 1A Production pipe main body 1B Production pipe tip 2 Rotor 21 Pump rotor 21S Pump shaft 21o Shaft outer peripheral surface 22 Motor rotor 22M Magnetic member 3 Pump stator 3B Stator shroud lower surface 3E Stator extension 3H Stator main body 3S Stator shroud 30 Coupling sleeve 30d Lower end spline coupling 30i Sleeve inner peripheral surface 31 First convex portion 4 Support portion 40 Cover member 41 Fitting member 5 Impeller 51 Disk 51B Disk back surface 51M Disk main surface 52 Blade 53 Shroud cover 6 Thrust collar 61 Two projections 6d Lower end thrust collar 6H Thrust collar main body 7 Thrust pad 7d Lower end thrust pad 80 Through hole 80a Inlet 80b Outlet 81 Capturing part 9 Excavation pipe 90 Section B Baffle plate Bd Lower end thrust bearing Bs Intermediate thrust bearing Bh Balance hole C Coil D1 First stepped portion D2 Second stepped portion Fi Suction flow path Fs Stator flow path H Opening M Motor O Axis P1 Opposed surface P2 Connection surface P3 Downstream surface Pt Protruding portion S1 First seal portion S2 Second seal portion V Vane Ws swirl wing

Claims (7)

a cylindrical production pipe along an axis extending in the vertical direction;
a pump rotor extending axially within the production tube;
a pump stator enclosing the pump rotor between the production tube and the pump rotor;
with
The pump rotor is
a plurality of pump shafts sequentially connected in the axial direction;
an impeller that is provided with a plurality of stages on each of these pump shafts and pumps up the crude oil by rotating together with the pump shaft;
a thrust collar provided on each of the pump shafts and projecting radially outward;
has
The pump stator is
a cylindrical stator body extending along the axis;
a thrust pad projecting from the inner peripheral surface of the stator main body radially inward of the axis and supporting the thrust collar slidably in the circumferential direction from below;
oil drilling pump with The pump stator is
a first convex portion protruding upward so as to cover the sliding surface between the thrust collar and the thrust pad from the outer peripheral side;
2. The crude oil drilling pump according to claim 1, wherein the thrust collar has a second projection projecting radially outward and facing the upper end of the first projection from below. The impeller is
a disc-shaped disc fixed to the pump shaft;
blades circumferentially spaced on the downwardly facing surface of the disc;
a shroud cover that covers the blade from below;
has
A first seal portion forming a clearance between the shroud cover and the pump stator is formed on the outer peripheral surface of the shroud cover,
A second sealing portion forming a clearance between the pump stator and the pump stator is formed on the rear surface of the disk facing upward,
The area of a first region radially outward of the first seal portion in the shroud cover when viewed in the axial direction is the area of a second region radially outward of the second seal portion of the disc rear surface when viewed in the axial direction. 3. A crude oil drilling pump according to claim 1 or 2, which is greater than. The pump stator is
a plurality of radially extending baffle plates provided at intervals in the circumferential direction on a facing surface of the pump stator, which is a portion facing the outer peripheral surface of the shroud cover ;
The impeller is
4. A crude oil drilling pump according to claim 3, further comprising radially extending swirler vanes circumferentially spaced on the back surface of said disk. The pair of pump shafts that are vertically adjacent to each other are arranged with an upper end and a lower end spaced apart from each other,
having a coupling sleeve that connects the pair of pump shafts so as to cover them from the outer peripheral side;
a through hole is formed in the coupling sleeve so as to penetrate the coupling sleeve in a radial direction and open to a gap between the pair of pump shafts;
5. The crude oil drilling pump according to any one of claims 1 to 4, wherein a part of said through-hole has a capture portion for capturing slurry in said crude oil. further comprising fitting members respectively fitted to the pair of pump shafts,
The coupling sleeve is spline-fitted to each of the pair of fitting members to connect the pair of pump shafts,
6. The crude oil drilling pump according to claim 5, further comprising a cover member on upper ends of said fitting member and said coupling sleeve to cover a gap therebetween. 7. The crude oil drilling pump according to claim 5, wherein the through-hole extends rearward in the rotational direction of the pump shaft as it goes from the radially inner side to the outer side.

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