Pump

Abstract

To extend life by reducing wear of bearings in a pump.SOLUTION: A pump comprises: a casing having a hollow shape; a rotating shaft arranged along a vertical direction inside the casing; an impeller provided on the rotating shaft; a plurality of radial bearings for rotatably supporting the rotating shaft with respect to the casing, and receiving a load in a direction perpendicular to the rotating shaft; and a noncontact axial bearing for rotatably supporting the rotating shaft with respect to the casing, and receiving a load in an axial direction to the rotating shaft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to pumps. [Background technology]

[0002] Vertical rotary pumps are pumps that pressurize fluids. A vertical rotary pump has a rotating shaft arranged vertically inside a casing, which is rotatably supported by bearings in the casing and has an impeller fixed to its lower end. In this case, bearings are generally provided at the top and bottom of the casing, rotatably supporting the rotating shaft at two locations. Examples of such pumps include those described in Patent Documents 1 and 2.

[0003] The pumps described in Patent Documents 1 and 2 support the rotating shaft with rolling bearings (radial bearings) at different axial positions and are equipped with an axial thrust balancing device. The radial load acting on the rotating shaft is supported by multiple ball bearings, and the thrust load acting on the rotating shaft is eliminated or reduced by the axial thrust balancing device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-296586 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-297786 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional pumps, the rotating shaft is supported by multiple rolling bearings (radial bearings), and the multiple rolling bearings absorb the radial load acting on the rotating shaft. It is also conceivable that conventional pumps would absorb the thrust load acting on the rotating shaft using a single ball bearing. However, in this case, the rolling bearing absorbs both the radial load and the thrust load, resulting in excessive load acting on the rolling bearing, accelerating wear on the rolling bearing and shortening its lifespan. Providing an axial thrust balancing device, as in the pumps described in Patent Documents 1 and 2, poses the problem of a complex structure.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a pump that extends the lifespan by reducing bearing wear. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the pump of the present disclosure comprises a hollow casing, a rotating shaft arranged vertically inside the casing, an impeller provided on the rotating shaft, a plurality of radial bearings that rotatably support the rotating shaft relative to the casing and receive loads in a direction perpendicular to the rotating shaft, and a non-contact axial bearing that rotatably support the rotating shaft relative to the casing and receive loads in the axial direction of the rotating shaft. [Effects of the Invention]

[0008] According to the pump of the present disclosure, the wear on the bearings can be reduced, thereby extending their lifespan. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the pump of this embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view showing a non-contact axial bearing. [Figure 3] FIG. 3 is a cross-sectional view of the non-contact axial bearing taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a main part of a non-contact axial bearing. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0011] <Pump configuration> FIG. 1 is a schematic diagram showing the pump of this embodiment.

[0012] 1, pump 30 has a drive unit 31 and a pump body 32, and drive unit 31 has a drive motor 33. Pump body 32 is a device for pressurizing a liquid (e.g., liquid hydrogen) as a fluid. Note that the fluid is not limited to liquid hydrogen, and may be other liquids or gases.

[0013] The tank 41 is a container for storing liquid and is also a vacuum insulated container. The tank 41 is provided with an outer peripheral flange 41a at the top and is mounted on a stand (not shown). The upper flange 42 is placed on top of the tank 41 with the pump body 32 suspended, and is installed in an airtight manner. The tank 41 is a cylindrical, bottomed, insulated structure, and has an internal liquid storage chamber 43.

[0014] A supply pipe 44 and a gas exhaust pipe 45 are connected to the side of the tank 41. The supply pipe 44 is a pipe for supplying liquid from an external supply source to the liquid storage chamber 43 of the tank 41. The supply pipe 44 is provided on the bottom side of the tank 41. The gas exhaust pipe 45 is a pipe for exhausting components vaporized in the liquid storage chamber 43 to the outside. The gas exhaust pipe 45 is provided above the supply pipe 44.

[0015] The pump body 32 is disposed inside the tank 41. The pump body 32 includes a casing 51, a rotary shaft 52, a plurality of impellers 53A, 53B, and 53C, a plurality of radial bearings and 55, and a non-contact axial bearing .

[0016] The casing 51 has a hollow shape. The casing 51 may be made of a single member, or may be made by assembling multiple members together. The casing 51 is disposed inside the tank 41, and is supported by being suspended by connecting its upper end to the upper flange 42. The casing 51 has a cylindrical shape centered on an axis O along the vertical direction, but is not limited to a cylindrical shape. Furthermore, the axis O is the center of the tank 41 and the casing 51, but the center of the tank 41 and the center of the casing 51 may be offset from each other.

[0017] Casing 51 is provided with suction section 61 at its lower end and discharge section 62 at its upper end. Suction section 61 opens toward the liquid stored in liquid storage chamber 43 of tank 41. Discharge section 62 is connected to discharge pipe 63. Note that suction section 61 may be directly connected to a pipe extending from supply pipe 44 or another supply pipe. In other words, the liquid may be introduced directly into suction section 61 from the pipe without first being stored in liquid storage chamber 43 of tank 41.

[0018] The rotating shaft 52 is disposed vertically inside the casing 51. The rotating shaft 52 has a cylindrical shape centered on the axis O. The casing 51 and the rotating shaft 52 are disposed concentrically around the axis O. The impellers 53A, 53B, and 53C are provided on the rotating shaft 52. A plurality of the impellers 53A, 53B, and 53C (three in this embodiment) are disposed at intervals in the axial direction of the rotating shaft 52. The impeller 53A is fixed to the lower end of the rotating shaft 52 and is integrally provided with an inducer 64. However, the inducer 64 does not necessarily have to be provided at the lower end of the rotating shaft 52. The impeller 53A and the inducer 64 are located in the suction section 61 of the casing 51. The impellers 53B and 53C are fixed to the rotating shaft 52 vertically above the impeller 53A.

[0019] Impellers 53A, 53B, 53C and inducer 64 are integrally provided on rotary shaft 52. Impellers 53A, 53B, 53C and inducer 64 are rotatable integrally with rotary shaft 52 and are also movable integrally in the axial direction. However, the number of impellers 53A, 53B, 53C is not limited to three, and may be two or less, or four or more.

[0020] When rotary shaft 52 rotates, impellers 53A, 53B, 53C and inducer 64 rotate integrally. Then, the liquid in liquid storage chamber 43 is sucked into suction section 61 by inducer 64, and is pressurized by one stage by impeller 53A. The liquid pressurized by one stage is supplied to impeller 53B through passage 65 provided in casing 51. Here, the liquid is pressurized by two stages by impeller 53B. Here, the liquid pressurized by two stages is supplied to impeller 53C through passage 66 provided in casing 51. Here, the liquid is pressurized by three stages by impeller 53C.

[0021] The liquid pressurized in three stages by impeller 53C is supplied to discharge part 62 through passage 67 provided in casing 51 and discharged from discharge pipe 63. Note that it is preferable that a plurality of passages 65, 66, 67 are provided at intervals in the circumferential direction on the outside of impellers 53A, 53B, 53C.

[0022] The radial bearings 54, 55 support the rotating shaft 52 rotatably relative to the casing 51. A plurality of radial bearings 54, 55 (two in this embodiment) are provided. The radial bearing 54 is arranged at the upper part of the casing 51 in the vertical direction, and the radial bearing 55 is arranged at the lower part of the casing 51 in the vertical direction. The number of radial bearings 54, 55 is not limited to two, and three or more may be provided. The radial bearings 54, 55 receive a load in a direction perpendicular to the rotating shaft 52 (the radial direction of the rotating shaft 52). The radial bearings 54, 55 are preferably rolling bearings (ball bearings), but are not limited to rolling bearings (ball bearings). The radial bearings 54, 55 may be non-contact bearings.

[0023] The non-contact axial bearing 56 rotatably supports the rotating shaft 52 relative to the casing 51. The non-contact axial bearing 56 is disposed in a vertically intermediate portion of the casing 51. Specifically, the non-contact axial bearing 56 is disposed vertically above the multiple radial bearings 54, 55. However, the position of the non-contact axial bearing 56 is not limited to being above the multiple radial bearings 54, 55, and may be between the multiple radial bearings 54, 55 or below the multiple radial bearings 54, 55.

[0024] The non-contact axial bearing 56 bears the axial load of the rotating shaft 52. A hydrostatic bearing is applied to the non-contact axial bearing 56. However, the non-contact axial bearing 56 is not limited to a hydrostatic bearing, and a magnetic bearing may also be applied. Since the non-contact axial bearing 56 is a hydrostatic bearing, it has a disk 71, a bearing body 72, and a fluid supply mechanism 73. The disk 71 is fixed to the outer periphery of the rotating shaft 52. The disk 71 is rotatable integrally with the rotating shaft 52 and is also movable axially integrally therewith. The bearing body 72 is fixed to the casing 51. The bearing body 72 forms a manifold for applying axial pressure to an upper surface 71a and a lower surface 71b of the disk 71. The manifolds 81b, 82b (see FIG. 4) apply uniform pressure in the circumferential direction by supplying an appropriate amount of high-pressure liquid to the entire circumferential area of the upper surface 71a and the lower surface 71b of the disk 71. The fluid supply mechanism 73 applies fluid pressure to the upper surface 71a and the lower surface 71b of the disk 71 by supplying fluid to the bearing body 72.

[0025] Fluid supply mechanism 73 supplies fluid pressurized by impellers 53A, 53B, and 53C to upper surface 71a and lower surface 71b of disk 71. Fluid supply mechanism 73 has a supply passage 74 that connects passage 67 and bearing body 72. When rotating shaft 52 rotates, impellers 53A, 53B, and 53C rotate to pressurize the liquid and supply the high-pressure liquid to passage 67. Fluid supply mechanism 73 supplies a portion of the high-pressure liquid that has been pressurized in three stages by impeller 53C and flows through passage 67 from supply passage 74 to bearing body 72, where it acts on upper surface 71a and lower surface 71b of disk 71.

[0026] When the rotating shaft 52 starts to rotate, the impellers 53A, 53B, and 53C do not rotate and the liquid cannot be pressurized, so the fluid supply mechanism 73 applies fluid (high-pressure liquid) supplied from the outside to the upper surface 71a and lower surface 71b of the disc 71.

[0027] The casing 51 also houses a drive motor 33 that constitutes the drive unit 31. The drive motor 33 is disposed between the impeller 53C and the radial bearing 54. The drive motor 33 has a stator 76 and a rotor 77. The casing 51 has the stator 76 fixed to its inner periphery. The stator 76 is cylindrical and has a stator core and a stator coil. The rotating shaft 52 has the rotor 77 fixed to its outer periphery. The rotor 77 is cylindrical and has a rotor core (for example, a permanent magnet or laminated steel plates). In the drive motor 33, the stator 76 fixed to the casing 51 and the rotor 77 fixed to the rotating shaft 52 face each other in the radial direction with a gap between them.

[0028] <Non-contact axial bearing> FIG. 2 is a longitudinal cross-sectional view showing a non-contact axial bearing, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 showing the non-contact axial bearing, and FIG. 4 is a cross-sectional view showing a main part of the non-contact axial bearing.

[0029] As shown in Figures 2 to 4, the non-contact axial bearing 56 receives an axial load acting on the rotating shaft 52. The non-contact axial bearing 56 is a hydrostatic bearing. The non-contact axial bearing 56 has a disk 71, which is fixed to the rotating shaft 52. The non-contact axial bearing 56 has a bearing body 72. The bearing body 72 has an upper bearing body 81 and a lower bearing body 82.

[0030] The upper bearing body 81 and the lower bearing body 82 are ring-shaped. The upper bearing body 81 is fixed to the casing 51 so as to face the outer periphery of the upper surface 71a of the disk 71 with a gap in the axial direction. The lower bearing body 82 is fixed to the casing 51 so as to face the outer periphery of the lower surface 71b of the disk 71 with a gap in the axial direction. The upper bearing body 81 has an upper pocket 81a formed at a position facing the upper surface 71a of the disk 71. A plurality of upper pockets 81a (four in this embodiment) are provided at intervals in the circumferential direction. The lower bearing body 82 has a lower pocket 82a formed at a position facing the lower surface 71b of the disk 71 with a gap in the circumferential direction.

[0031] Additionally, an upper manifold 81b is formed on the upper surface of the upper bearing body 81 that does not face the upper surface 71a of the disk 71. The upper manifold 81b has a circular ring shape that extends in the circumferential direction. A lower manifold 82b is formed on the lower surface of the lower bearing body 82 that does not face the lower surface 71b of the disk 71. The lower manifold 82b has a circular ring shape that extends in the circumferential direction. The upper pocket 81a and the upper manifold 81b are communicated by a communicating passage 81c. The lower pocket 82a and the lower manifold 82b are communicated by a communicating passage 82c.

[0032] The supply passage 74 branches into an upper supply passage 74a and a lower supply passage 74b. The upper supply passage 74a is connected to an upper manifold 81b, and the lower supply passage 74b is connected to a lower manifold 82b. A high-pressure fluid supply device 91 is provided outside the pump body 32, and a supply passage 92 extending from the high-pressure fluid supply device 91 is connected to the supply passage 74. The high-pressure fluid supply device 91 is, for example, a compressor or an accumulator pump. The number of divisions of the upper pocket 81a and the lower pocket 82a is not limited to four, and may be three or less or five or more.

[0033] When the pump body 32 is started, that is, before the rotating shaft 52 reaches a predetermined rotational speed, the impellers 53A, 53B, and 53C cannot pressurize the liquid to a predetermined pressure. At this time, the fluid supply mechanism 73 supplies high-pressure liquid from the supply passage 92 and the supply passage 74 to the bearing body 72 using the high-pressure fluid supply device 91. That is, the high-pressure liquid is supplied from the upper supply passage 74a to the upper bearing body 81 and from the lower supply passage 74b to the lower bearing body 82. The high-pressure liquid supplied to the upper bearing body 81 then passes from the upper manifold 81b through the connecting passages 81c to the upper pockets 81a and acts on the upper surface 71a of the disk 71. The high-pressure liquid supplied to the lower bearing body 82 passes from the lower manifold 82b through the connecting passages 82c to the lower pockets 82a and acts on the lower surface 71b of the disk 71.

[0034] Here, because the liquid pressure acting on the upper surface 71a and the lower surface 71b is approximately the same, the disk 71 is held in a neutral position between the upper bearing body 81 and the lower bearing body 82, where they do not come into contact with each other. Even if an axial load acts on the rotating shaft 52 to which the disk 71 is fixed, the vertical pressures acting on the lower surface 71b of the disk 71 prevent the rotating disk 71 from coming into contact with the upper bearing body 81 and the lower bearing body 82. That is, when the disk 71 moves upward due to the automatic adjustment mechanism, the load from the upper pocket 81a increases, pushing the disk 71 down, and when the disk 71 moves downward, the load from the lower pocket 82a increases, pushing the disk 71 up.

[0035] Thereafter, when pump body 32 starts and rotating shaft 52 reaches a predetermined rotation speed, impellers 53A, 53B, and 53C can pressurize the liquid to a predetermined pressure. At this time, fluid supply mechanism 73 stops operation of high-pressure fluid supply device 91 and supplies the high-pressure liquid pressurized by impeller 53C from supply passage 74 to bearing body 72. Therefore, disc 71 continues to be held in a neutral position between upper bearing body 81 and lower bearing body 82, where it does not come into contact with either of them.

[0036] <Pump operation> As shown in FIG. 1 , before driving the drive unit 31 (drive motor 33), high-pressure liquid is supplied to the non-contact axial bearing 56 by the high-pressure fluid supply device 91, which levitates the rotating shaft 52 via the disk 71. When the drive unit 31 (drive motor 33) is driven, the rotating shaft 52 is driven to rotate, which rotates the impellers 53A, 53B, 53C and the inducer 64 fixed to the rotating shaft 52, thereby operating the pump body 32. At this time, the radial bearings 54 and 55 support a load on the rotating shaft 52 in a direction perpendicular to the rotating shaft 52 (the radial direction of the rotating shaft 52). Furthermore, because high-pressure liquid is supplied to the non-contact axial bearing 56, the non-contact axial bearing 56 supports a load on the rotating shaft 52 in the axial direction.

[0037] When pump body 32 is operated, liquid in liquid storage chamber 43 is sucked into suction section 61 by inducer 64 and is pressurized by one stage by impeller 53A. The liquid pressurized by the first stage is supplied to impeller 53B through passage 65 and is pressurized by two stages. The liquid pressurized by the second stage is supplied to impeller 53C through passage 66 and is pressurized by three stages.

[0038] A portion of the liquid that has been pressurized in three stages is supplied from supply passage 74 to bearing body 72, and operates non-contact axial bearing 56. A portion of the liquid that has been pressurized in two stages rises along rotating shaft 52 and cools drive motor 33. Most of the liquid that has been pressurized in three stages is then supplied to discharge portion 62 through passage 67 and discharged from discharge pipe 63.

[0039] [Effects of this embodiment] The pump of the first aspect comprises a hollow casing 51, a rotating shaft 52 arranged vertically inside the casing 51, impellers 53A, 53B, and 53C provided on the rotating shaft 52, a plurality of radial bearings 54 and 55 that rotatably support the rotating shaft 52 relative to the casing 51 and receive loads perpendicular to the rotating shaft 52, and a non-contact axial bearing 56 that rotatably support the rotating shaft 52 relative to the casing 51 and receive loads in the axial direction of the rotating shaft 52.

[0040] In the pump according to the first aspect, the radial bearings 54, 55 rotatably support the rotating shaft 52 and receive loads perpendicular to the rotating shaft 52, while the non-contact axial bearing 56 rotatably supports the rotating shaft 52 and receives loads in the axial direction of the rotating shaft 52, thereby reducing wear on the radial bearings 54, 55 and thereby extending their lifespan.

[0041] The pump according to the second aspect is the pump according to the first aspect, and further, the non-contact axial bearing is a hydrostatic bearing, which prevents wear on the non-contact axial bearing 56 and reduces wear on the radial bearings 54 and 55, thereby extending their lifespan.

[0042] A pump according to a third aspect is the pump according to the first aspect, except that the non-contact axial bearing is a magnetic bearing, thereby preventing wear on the non-contact axial bearing 56 and reducing and extending wear on the radial bearings 54 and 55.

[0043] A pump according to a fourth aspect is the pump according to any one of the first to third aspects, wherein the radial bearing is a rolling bearing, thereby simplifying the structure.

[0044] A pump according to a fifth aspect is the pump according to any one of the first to fourth aspects, and further includes non-contact axial bearing 56 disposed vertically above the plurality of radial bearings 54, 55. This improves the ease of maintenance of non-contact axial bearing 56.

[0045] A pump according to a sixth aspect is the pump according to any one of the first to fifth aspects, and further includes non-contact axial bearing 56 having a disk 71 fixed to rotating shaft 52 and a fluid supply mechanism 73 that supplies fluid to an upper surface 71a and a lower surface 71b of disk 71. This allows non-contact axial bearing 56 to be configured with a simple structure, thereby simplifying the structure.

[0046] The pump according to the seventh aspect is the pump according to the sixth aspect, further comprising: fluid supply mechanism 73 that supplies fluid pressurized by impellers 53A, 53B, and 53C to upper surface 71a and lower surface 71b of disk 71. This eliminates the need to supply fluid from an external source, and by operating non-contact axial bearing 56 using a minimum amount of fluid, loss of pressurized fluid can be minimized.

[0047] The pump according to an eighth aspect is the pump according to the sixth or seventh aspect, and further includes a fluid supply mechanism 73 that supplies fluid, supplied from the outside, to the upper surface 71a and the lower surface 71b of the disk 71 when the rotating shaft 52 starts to rotate. This allows the non-contact axial bearing 56 to operate from the start of the pump body 32, thereby preventing wear on the non-contact axial bearing 56 and reducing wear on the radial bearings 54, 55, thereby extending their lifespan. [Explanation of symbols]

[0048] 30 Pump 31 Drive unit 32 Pump body 33 Drive motor 41 Tank 42 Upper flange 43 Liquid storage chamber 44 Supply pipe 45 Gas exhaust pipe 51 Casing 52 Rotation axis 53A, 53B, 53C impellers 54,55 Radial bearings 56 Non-contact axial bearing 61 Suction part 62 Discharge part 63 Discharge pipe 64 Inducer 65, 66, 67 aisles 71 Disc 72 Bearing body 73 Fluid supply mechanism 74 Supply passage 76 Stator 77 Rotor 81 Upper bearing body 82 Lower bearing body 91 High-pressure fluid supply device 92 Supply passage

Claims

1. a hollow casing; a rotating shaft disposed vertically inside the casing; an impeller provided on the rotating shaft; a plurality of radial bearings that rotatably support the rotary shaft relative to the casing and receive a load in a direction perpendicular to the rotary shaft; a non-contact axial bearing that rotatably supports the rotary shaft with respect to the casing and receives an axial load of the rotary shaft; A pump comprising:

2. The non-contact axial bearing is a hydrostatic bearing.

2. The pump of claim 1.

3. The non-contact axial bearing is a magnetic bearing.

2. The pump of claim 1.

4. The radial bearing is a rolling bearing. A pump according to any one of claims 1 to 3.

5. the non-contact axial bearing is disposed vertically above the plurality of radial bearings; 2. The pump of claim 1.

6. The non-contact axial bearing includes a disk fixed to the rotating shaft and a fluid supply mechanism that supplies fluid to an upper surface and a lower surface of the disk.

2. The pump of claim 1.

7. the fluid supply mechanism supplies the fluid pressurized by the impeller to the upper and lower surfaces of the disk.

7. The pump of claim 6.

8. the fluid supply mechanism supplies fluid supplied from an external source to the upper and lower surfaces of the disk when the rotation shaft starts to rotate; A pump according to claim 6 or claim 7.

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