Pumping device

Abstract

The present invention provides a pumping device that can suppress vibration even when pumping low-viscosity, low-temperature fluids at high pressure and high flow rates. [Solution] The pump device comprises a rotating shaft centered on an axis extending vertically, an upper radial bearing that supports the upper part of the rotating shaft so as to be rotatable around the axis, a lower radial bearing that supports the lower part of the rotating shaft so as to be rotatable around the axis, a first seal mechanism provided between the upper radial bearing and the lower radial bearing, an electric motor that rotates the rotating shaft around the axis between the upper radial bearing and the first seal mechanism, a plurality of impellers provided below the first seal mechanism for pumping a low-viscosity, low-temperature fluid from below upward, and a second seal mechanism provided between the lower radial bearing and the first seal mechanism, wherein the plurality of impellers include a pair of impellers mounted back-to-back, and the second seal mechanism is provided at the mounting position of the pair of impellers mounted back-to-back.

Description

Technical Field

[0001] The present disclosure relates to a pump device.

Background Art

[0002] Patent Document 1 discloses a pump for pumping a low-viscosity cryogenic fluid. This pump includes a pump section for increasing the pressure of the fluid and a motor section for driving the pump section.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the pump pumps at high pressure and large flow rate, it has been an issue that the rotating shaft vibrates greatly due to the flow of the low-viscosity cryogenic fluid.

[0005] The present disclosure provides a pump device capable of suppressing vibration even when pumping a low-viscosity cryogenic fluid at high pressure and large flow rate.

Means for Solving the Problems

[0006] To solve the above problems, the pump device according to the present disclosure comprises: a rotating shaft centered on an axis extending in the vertical direction; an upper radial bearing that rotatably supports the upper part of the rotating shaft around the axis; a lower radial bearing that rotatably supports the lower part of the rotating shaft around the axis; a first seal mechanism provided between the upper radial bearing and the lower radial bearing, through which the rotating shaft is inserted; an electric motor between the upper radial bearing and the first seal mechanism that rotates the rotating shaft around the axis; a plurality of impellers provided below the first seal mechanism that pump a low-viscosity, low-temperature fluid from below upward as the rotating shaft rotates around the axis; and a second seal mechanism provided between the lower radial bearing and the first seal mechanism, through which the rotating shaft is inserted, wherein the plurality of impellers include a pair of impellers mounted back-to-back, and the second seal mechanism is provided at the mounting position of the pair of impellers mounted back-to-back. [Effects of the Invention]

[0007] According to the pump device of this disclosure, vibration can be suppressed even when pumping low-viscosity, low-temperature fluids at high pressure and high flow rates. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a pump device according to the first embodiment of this disclosure. [Figure 2] This is a schematic diagram of a pump device according to a second embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] <First Embodiment> (Pump system configuration) Hereinafter, a pump device 1 according to the first embodiment of this disclosure will be described with reference to Figure 1. The pump device is a device for pressurizing a low-viscosity cryogenic fluid L. In this embodiment, the case in which the cryogenic fluid L is liquid hydrogen will be described as an example. However, the cryogenic fluid L pressurized by the pump device 1 is not limited to liquid hydrogen, but may be other liquids or gases. For example, the cryogenic fluid L may be a liquefied gas other than liquid hydrogen, such as natural gas (LNG) or liquefied petroleum gas (LPG). The pump device 1 pumps the cryogenic fluid L at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h. As shown in Figure 1, the pump device 1 comprises a sump 10 and a cryogenic fluid pump 20.

[0010] (Sample) Sump 10 stores a cryogenic fluid L (liquid hydrogen in this embodiment). Sump 10 is a vacuum-insulated container. That is, sump 10 is an insulated structure with a bottomed cylindrical shape. Sump 10 is installed on a stand (not shown). Sump 10 has a sump body 11, an outer flange 12, an upper flange 13, and a mounting wall 14. The sump body 11 is formed in a bottomed cylindrical shape that opens upward. A liquid storage chamber 15 is formed inside the sump body 11. The cryogenic fluid L is stored in the liquid storage chamber 15. A supply pipe 2 and a gas discharge pipe 3 are connected to the side of the sump body 11. The supply pipe 2 is a pipe that allows the cryogenic fluid L to be supplied into the liquid storage chamber 15 from an external supply source. The gas discharge pipe 3 is a pipe that allows the gaseous component of the cryogenic fluid L that has vaporized in the liquid storage chamber 15 to be discharged to the outside of sump 10. The gas discharge pipe 3 is positioned vertically above the supply pipe 2. The gas discharge pipe 3 may also be configured to allow the liquid portion of the cryogenic fluid L to be discharged to the outside of the sump 10.

[0011] The outer flange 12 is provided on the upper part of the side of the sump body 11 and protrudes from the outer surface of the sump body 11. The upper flange 13 is attached to the upper part of the sump body 11. It closes the opening of the sump body 11. The upper flange 13 is attached to the outer flange 12 from above to maintain airtightness within the liquid storage chamber 15. The mounting wall portion 14 is attached to the lower surface of the upper flange 13. The mounting wall portion 14 is a flat plate-shaped member that extends horizontally.

[0012] (Cryogenic fluid pump) The cryogenic fluid pump 20 is a device that pressurizes and pumps a cryogenic fluid L (liquid hydrogen in this embodiment) to a desired pressure. The cryogenic fluid pump 20 is located inside the sump 10. The cryogenic fluid pump 20 in this embodiment comprises a rotating shaft 21, a casing 30, a bearing device 40, an electric motor 50, a first seal mechanism 4, a first outer seal portion 7, an impeller 55, a second seal mechanism 5, a second outer seal portion 8, an inducer 6, and a cryogenic fluid flow path 60.

[0013] (Axis of rotation) The rotation axis 21 is centered on an axis O that extends in the vertical direction Dv. One side in the direction of axis O is the lower side Dvd, and the other side in the direction of axis O is the upper side Dvu. Furthermore, the circumferential direction with respect to axis O will be simply referred to as the circumferential direction, and the radial direction with respect to axis O will be simply referred to as the radial direction. The rotation axis 21 is provided so as to be rotatable around this axis O.

[0014] (Casing) The casing 30 forms the outer shell of the cryogenic fluid pump 20. The casing 30 is hollow. The casing 30 is suspended from the upper flange 13 via the mounting wall 14. The casing 30 is cylindrical, but not limited to, an axis O extending vertically. Although both the sump 10 and the casing 30 extend from the axis O, the centers of the sump 10 and the casing 30 may be offset. The casing 30 houses the components of the cryogenic fluid pump 20, including the rotating shaft 21, bearing device 40, electric motor 50, first seal mechanism 4, first outer seal part 7, impeller 55, second seal mechanism 5, second outer seal part 8, inducer 6, etc. The casing 30 may be composed of a single component, or it may be composed of multiple components assembled together.

[0015] In this embodiment, the casing 30 includes a motor casing 31, a pump casing 32, and a flange portion 33. The motor casing 31 is formed in a bottomed cylindrical shape that opens downward. The pump casing 32 is located below the motor casing 31. The pump casing 32 is formed in a bottomed cylindrical shape that opens upward. The flange portion 33 includes an upper flange 33a provided at the lower end of the motor casing 31 and a lower flange 33b provided at the upper end of the pump casing 32. The upper flange 33a protrudes radially outward from the outer circumferential surface of the motor casing 31. The upper flange 33a is formed integrally with the motor casing 31. The lower flange 33b protrudes radially outward from the outer circumferential surface of the pump casing 32. The lower flange 33b is formed integrally with the pump casing 32. The lower flange 33b contacts the upper flange 33a and is fixed to the upper flange 33a by means of bolts (not shown), for example. The flange portion 33 firmly assembles the motor casing 31 and the pump casing 32.

[0016] A suction part 34 is provided at the lower end of the pump casing 32. The suction part 34 is open downward. The low-temperature fluid L stored in the liquid storage chamber 15 of the sump 10 is inhaled into the casing 30 through the suction part 34. Note that the suction part 34 may be directly connected to the supply pipe 2 or other pipes extended from the supply pipe 2. That is, the low-temperature fluid L may be introduced directly from the pipe into the suction part 34 without being temporarily stored in the liquid storage chamber 15 of the sump 10.

[0017] An upper accommodation chamber 35 is formed at the upper end of the motor casing 31. The upper end of the rotary shaft 21 is accommodated in the upper accommodation chamber 35. The low-temperature fluid L flowing upward along the rotary shaft can penetrate into the upper accommodation chamber 35.

[0018] (Bearing device) The bearing device 40 is a device that supports the rotary shaft 21 so as to be rotatable about the axis O. The bearing device 40 includes a radial bearing 41, a thrust disk 42, and a thrust bearing 43.

[0019] (Radial bearing) The radial bearing 41 is arranged to receive the radial load of the rotating shaft 21. That is, the radial bearing 41 is arranged concentrically with the rotating shaft 21 and is provided so as to cover the rotating shaft 21 from the outer peripheral surface. A plurality of radial bearings 41 are provided. In the present embodiment, an upper radial bearing 41a and a lower radial bearing 41b are provided. The upper radial bearing 41a is arranged above the casing 30 in the vertical direction. The upper radial bearing 41a supports the upper part of the rotating shaft 21 so as to be rotatable about the axis O. The lower radial bearing 41b is arranged below the casing 30 in the vertical direction. The lower radial bearing 41b supports the lower part of the rotating shaft so as to be rotatable about the axis O. The type of the radial bearing is not limited. For example, the radial bearing 41 may be a rolling bearing, a sliding bearing, or a magnetic bearing. Also, the upper radial bearing 41a and the lower radial bearing 41b may be bearings of the same type or bearings of different types. Hereinafter, the embodiment will be described by taking the case where both the upper radial bearing 41a and the lower radial bearing 41b are magnetic bearings as an example.

[0020] (Thrust disk) The thrust disk 42 is fixed to the outer peripheral portion of the rotating shaft 21. The thrust disk 42 is in a disk shape provided so as to expand the diameter of the rotating shaft 21 in the radial direction while being fixed to the rotating shaft 21. The thrust disk 42 is rotatable integrally with the rotating shaft 21. Also, the thrust disk 42 is movable integrally with the rotating shaft 21 in the direction of the axis O.

[0021] (Thrust bearing) The thrust bearing 43 is provided so as to sandwich the thrust disk 42 in the direction of the axis O. The thrust bearing 43 in the present embodiment is a hydrostatic bearing. The thrust bearing 43 is, for example, a non-contact bearing. For example, the thrust bearing 43 may be a magnetic bearing. However, the thrust bearing 43 is not limited to non-contact bearings. Also, the thrust bearing 43 is arranged above the upper radial bearing 41a and the lower radial bearing 41b in the vertical direction.

[0022] (First sealing mechanism) The first seal mechanism 4 is, for example, a seal mechanism called a balance sleeve. The first seal mechanism 4 is provided between the upper radial bearing 41a and the lower radial bearing 41b in the direction of axis O. The first seal mechanism 4 is formed in the shape of a disc centered on axis O, and the rotating shaft 21 is inserted through it. The first seal mechanism 4 is also provided at the same position in the direction of axis O as the flange portion 33 of the casing 30, that is, at a position that radially overlaps with the flange portion 33 of the casing 30. The first seal mechanism 4 is formed in the shape of a flange protruding from the rotating shaft 21. The first seal mechanism 4 divides the space inside the casing 30 in the vertical direction Dv. The first seal mechanism 4 is covered from the radially outer side by the first outer seal portion 7. A gap is provided between the outer circumferential surface of the first seal mechanism 4 and the inner circumferential surface of the first outer seal portion 7, such that a pressure difference is created between the upper and lower parts of the first seal mechanism 4, while allowing the low-temperature fluid L to flow through. The pressure in the space above the first seal mechanism 4 is lower than the pressure in the space below the first seal mechanism 4. Therefore, a thrust force is applied to the first seal mechanism 4 from bottom to top along the axis O. This thrust force from bottom to top is regulated by the first seal mechanism 4. Also, within the casing 30, the pressure in the space above the first seal mechanism 4 gradually decreases as you move upward, but the pressure remains roughly the same from the first seal mechanism 4 to the upper housing chamber 35. The pressure inside the upper housing chamber 35 is an intermediate pressure, similar to that between the second stage impeller 55b and the third stage impeller 55c, due to the balance piping 65 described later.

[0023] (Electric motor) The electric motor 50 rotates the rotating shaft 21 around axis O between the upper radial bearing 41a and the first seal mechanism 4 in the direction of axis O. The electric motor 50 has a stator 51 and a rotor 52. The stator 51 is fitted to the inner circumferential surface of the casing 30. The stator 51 is cylindrical in shape and has a stator core and stator coils. The rotor 52 is integrally fixed to the rotating shaft 21 inside the stator 51. The rotor 52 is cylindrical in shape and has a rotor core (for example, a permanent magnet or laminated steel plate). The stator 51 fixed to the casing 30 and the rotor 52 fixed to the rotating shaft 21 face each other radially with a gap between them.

[0024] (Impeller) Multiple impellers 55 are provided below the first seal mechanism 4. The multiple impellers 55 pump the low-temperature fluid L from below upward as they rotate around the axis O of the rotating shaft 21. The multiple impellers 55 include a pair of impellers 55 mounted back-to-back. In this embodiment, the lower radial bearing 41b is provided between two adjacent impellers 55. The number of impellers 55 can be changed as appropriate, but in this embodiment, the case in which five stages of impellers 55 are provided will be described.

[0025] Multiple impellers 55 gradually pump the low-temperature fluid L drawn into the casing 30 from the suction section 34. Hereinafter, the five impellers 55 will be referred to as the first-stage impeller 55a, second-stage impeller 55b, third-stage impeller 55c, fourth-stage impeller 55d, and fifth-stage impeller 55e, in order from the low-pressure side. The first-stage impeller 55a may be described as the low-pressure impeller 55, the second-stage impeller 55b and third-stage impeller 55c as the intermediate-pressure impellers 55, and the fourth-stage impeller 55d and fifth-stage impeller 55e as the high-pressure impellers 55. In addition, the fifth-stage impeller 55e may be described as the final-stage impeller 55.

[0026] The first stage impeller 55a is positioned below the lower radial bearing 41b. The first stage impeller 55a is positioned to pump the cryogenic fluid L upward. The second stage impellers 55b to the fifth stage impellers 55e are located between the lower radial bearing 41b and the first seal mechanism 4 in the axial direction O (vertical direction Dv). From bottom to top, the second stage impeller 55b, third stage impeller 55c, fifth stage impeller 55e, and fourth stage impeller 55d are positioned. The second stage impeller 55b and third stage impeller 55c are positioned to pump the cryogenic fluid L upward, while the fourth stage impeller 55d and fifth stage impeller 55e are positioned to pump the cryogenic fluid L downward. The third stage impeller 55c and fifth stage impeller 55e are positioned back to back.

[0027] (Second sealing mechanism) The second sealing mechanism 5 is, for example, a sealing mechanism called a center stage. The second sealing mechanism 5 is provided between the lower radial bearing 41b and the first sealing mechanism 4. The second sealing mechanism 5 is formed in a cylindrical shape with axis O as its center, and the rotating shaft 21 is inserted through it. The second sealing mechanism 5 is provided at the mounting positions of a pair of impellers (in this embodiment, the third stage impeller 55c and the fifth stage impeller 55e) that are mounted back-to-back. More specifically, the back-to-back third stage impeller 55c and the fifth stage impeller 55e are fitted onto the outer circumferential surface of the second sealing mechanism 5.

[0028] (Inducer) The inducer 6 is located below the lower radial bearing 41b and the multiple impellers. The inducer 6 is positioned within the suction section 34 of the casing 30. The inducer 6 rotates integrally with the rotating shaft 21. This rotation of the inducer 6 draws the low-temperature fluid L into the casing 30.

[0029] (Low-temperature fluid channel) The low-temperature fluid passage 60 carries the low-temperature fluid L. The low-temperature fluid passage 60 has a main passage 61, a discharge section 62, a discharge pipe 63, a branch passage 64, and a balance pipe 65. The main passage 61 is shown with a solid line, the branch passage 64 with a dashed line, and the balance pipe 65 with a dotted line.

[0030] (Main channel) The main flow path 61 allows the low-temperature fluid L to flow through multiple impellers 55. The main flow path 61 includes a first main flow path 61a, a second main flow path 61b, and a third main flow path 61c. The first main flow path 61a guides the low-pressure, cryogenic fluid L, which has been pressurized by the first-stage impeller 55a, to the second-stage impeller 55b. The first main flow path 61a is formed, for example, within the casing 30. The first main flow path 61a connects the first-stage impeller 55a and the second-stage impeller 55b so as to bypass the lower radial bearing 41b. The second main flow path 61b guides the intermediate-pressure, cryogenic fluid L, which has been pressurized by the second-stage impeller 55b and the third-stage impeller 55c, to the fourth-stage impeller 55d. The second main flow path 61b is formed, for example, within the casing 30. The third main flow path 61c guides the high-pressure, low-temperature fluid L, which has been pressurized by the fourth-stage impeller 55d and the fifth-stage impeller 55e, to the discharge section 62, which will be described later. The third main flow path 61c is, for example, a pipe located radially outward from the outer surface of the casing 30. The third main flow path 61c may also be provided inside the casing 30.

[0031] (Discharge part) The discharge section 62 is formed on the lower surface of the upper flange 13. When viewed from below, for example, the discharge section 62 is formed in a circular shape centered on axis O. High-pressure, low-temperature fluid L, which has been pressurized by a plurality of impellers 55, is supplied to the discharge section 62.

[0032] (discharge pipe) The discharge pipe 63 extends upward from the center of the discharge section 62. The discharge pipe 63 discharges the low-temperature fluid L from the discharge section 62 to the outside.

[0033] (Branching channel) The branch channel 64 branches off from the main channel 61 and allows the cryogenic fluid L to flow through the upper radial bearing 41a, the lower radial bearing 41b, the electric motor 50, and the thrust bearing 43. The branch channel 64 in this embodiment has a first branch channel 64a, a second branch channel 64b, and a third branch channel 64c. The first branch channel 64a supplies a portion of the cryogenic fluid L supplied from the first stage impeller 55a to the second stage impeller 55b to the lower radial bearing 41b. The first branch channel 64a in this embodiment is formed to return from the second stage impeller 55b through the lower radial bearing 41b to the first main channel 61a. The first branch channel 64a is composed of, for example, a passage formed within the casing 30 and gaps between each member. The cryogenic fluid L supplied to the lower radial bearing 41b is returned to the first main channel 61a. The second branch channel 64b returns a portion of the low-temperature fluid L supplied from the fifth-stage impeller 55e to the discharge section 62 to the third-stage impeller 55c. The second branch channel 64b is composed of, for example, a passage formed within the casing 30 and gaps between the various components. The third branch channel 64c supplies a portion of the low-temperature fluid L supplied from the third-stage impeller 55c to the fourth-stage impeller 55d to the upper first seal mechanism 4, the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43. The low-temperature fluid L that has passed through the thrust bearing 43 is temporarily stored in the upper storage chamber 35. The third branch channel 64c is composed of, for example, a passage formed within the casing 30 and gaps between the various components. In this embodiment, the third branch channel 64c is a gap between the various components within the casing 30, and the upstream end of the third branch channel 64c is the gap between the first seal mechanism 4 and the first outer seal section 7.

[0034] (Balanced piping) The balance pipe 65 returns the low-temperature fluid L that has passed through the upper radial bearing 41a, the electric motor 50, and the thrust bearing 43 to the intermediate-pressure impeller 55 among the multiple impellers 55 (in this embodiment, between the second-stage impeller 55b and the third-stage impeller 55c). By connecting the upper housing chamber 35 with the region between the second-stage impeller 55b and the third-stage impeller 55c within the casing 30, the balance pipe 65 reduces the pressure difference and suppresses the thrust force in the axial direction O applied to the first seal mechanism 4. The balance pipe 65 is, for example, a pipe positioned radially outward from the outer circumferential surface of the casing 30. The balance pipe 65 may also be provided inside the casing 30.

[0035] (Flow of cold fluids) Next, the flow of the low-temperature fluid during the operation of the pump device 1 will be explained. As shown in Figure 1, when the electric motor 50 is driven, the rotating shaft 21 rotates, and the impeller 5 and inducer 6 fixed to the rotating shaft 21 rotate. At this time, the rotating shaft 21 is subjected to loads perpendicular to the rotating shaft 21 (radial direction) by the radial bearing 41. In addition, the rotating shaft 21 is subjected to loads in the direction of axis O by the thrust bearing 43.

[0036] The cryogenic fluid L in the liquid storage chamber 15 is drawn into the suction section 34 by the inducer 6 and pressurized in stages by multiple impellers 55. The cryogenic fluid L drawn into the suction section 34 by the inducer 6 is pressurized by the first stage impeller 55a. Subsequently, the cryogenic fluid L is sent to the second stage impeller 55b through the first main flow path 61a. The cryogenic fluid L is further pressurized by the second stage impeller 55b and the third stage impeller 55c to become an intermediate-pressure cryogenic fluid L. Most of the intermediate-pressure cryogenic fluid L is sent to the fourth stage impeller 55d through the second main flow path 61b. At this time, a portion of the cryogenic fluid L is sent from the second stage impeller 55b to the lower radial bearing 41b through the first branch flow path 64a. This cryogenic fluid L has a cooling function as a lubricant for the lower radial bearing 41b. The cryogenic fluid L supplied to the lower radial bearing 41b passes through the first branch channel 64a and is returned to the first main channel 61a. In this way, a portion of the cryogenic fluid L circulates between the second stage impeller 55b and the lower radial bearing 41b.

[0037] The cryogenic fluid L sent from the third stage impeller 55c to the fourth stage impeller 55d is further pressurized by the fourth stage impeller 55d and the fifth stage impeller 55e to become high-pressure cryogenic fluid L. Most of the high-pressure cryogenic fluid L is sent to the discharge section 62 through the third main flow path 61c and discharged to the outside of the pump device 1 through the discharge pipe. At this time, a portion of the cryogenic fluid L supplied from the fifth stage impeller to the discharge section 62 is returned to the third stage impeller 55c from the fifth stage impeller 55e through the second branch flow path 64b. In addition, a portion of the cryogenic fluid L supplied to the fourth stage impeller 55d is sequentially supplied to the upper first seal mechanism 4, the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43 through the third branch flow path 64c. This cryogenic fluid L serves as a lubricant and cooling fluid for the first seal mechanism 4, the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43. The cryogenic fluid L supplied to the thrust bearing 43 is temporarily stored in the upper storage chamber 35. The cryogenic fluid L stored in the upper storage chamber 35 is returned to the intermediate-pressure impeller 55 (between the second-stage impeller 55b and the third-stage impeller 55c) via the balance pipe 65. This suppresses the gasification of the cryogenic fluid L compared to when it is returned to the lowest-pressure impeller 55. The cryogenic fluid L returned to the intermediate-pressure impeller 55 is then gradually pressurized again by the intermediate-pressure impeller 55 and the high-pressure impeller 55.

[0038] (Effects and Benefits) The pump device 1 with the above configuration can achieve the following effects. In this embodiment, the pump device 1 comprises a rotating shaft 21, an upper radial bearing 41a, a lower radial bearing 41b, a first seal mechanism 4, an electric motor 50, a plurality of impellers 55, and a second seal mechanism 5. The rotating shaft 21 is centered on an axis O that extends vertically. The upper radial bearing 41a supports the upper part of the rotating shaft 21 so that it can rotate around the axis O. The lower radial bearing 41b supports the lower part of the rotating shaft 21 so that it can rotate around the axis O. The first seal mechanism 4 is provided between the upper radial bearing 41a and the lower radial bearing 41b, and the rotating shaft 21 is inserted through it. The electric motor 50 rotates the rotating shaft 21 around the axis O between the upper radial bearing 41a and the first seal mechanism 4. Multiple impellers 55 are positioned below the first seal mechanism 4 and, as the rotating shaft 21 rotates around its axis O, pressurize the low-temperature fluid L from below upward. The second seal mechanism 5 is positioned between the lower radial bearing 41b and the first seal mechanism 4, through which the rotating shaft 21 is inserted. Furthermore, the multiple impellers 55 include a pair of impellers 55 mounted back-to-back, and the second seal mechanism 5 is positioned at the mounting location of the pair of back-to-back impellers 55.

[0039] According to the above configuration, both the upper and lower ends of the rotating shaft 21 are supported by the upper radial bearing 41a and the lower radial bearing 41b. This suppresses vibration of the rotating shaft 21 as a whole. The motor 50 and impeller 55, which are sources of vibration, are positioned between the upper radial bearing 41a and the lower radial bearing 41b, and the first seal mechanism 4 is positioned between the motor 50 and the impeller. The first seal mechanism 4 is, for example, called a balance sleeve. Furthermore, a second seal mechanism 5 is provided at the mounting position of the pair of impellers 55 that are mounted back-to-back. The second seal mechanism 5 is, for example, called a center stage. The first seal mechanism 4 and the second seal mechanism 5 provide damping to the rotating shaft 21, further suppressing vibration of the rotating shaft 21. Therefore, the pump device 1 of this embodiment can suppress vibration even when pumping high pressure and large flow rates. From another perspective, the first sealing mechanism 4 functions as a weight positioned between the electric motor 50 and the impeller 55. This causes the electric motor 50 and the impeller 55 to vibrate separately. This prevents the vibrations of the electric motor 50 and the impeller 55 from negatively affecting each other. As a result, the overall vibration of the pump device 1 is suppressed.

[0040] In this embodiment, the lower radial bearing 41b is located between two adjacent impellers 55.

[0041] The pump device 1 can supply the low-temperature fluid L, which is pressurized by the impeller 55, to the lower radial bearing 41b. This allows the pump device 1 to cool and lubricate the lower radial bearing 41b at the same time. In particular, in this embodiment, the lower radial bearing 41b is positioned between the first-stage impeller 55a and the second-stage impeller 55b, and the low-temperature fluid L is circulated between the first-stage impeller 55a and the lower radial bearing 41b by the first branch passage 64a. This allows the pump device 1 to cool and lubricate the lower radial bearing 41b with the low-temperature fluid L while suppressing the load on the lower radial bearing 41b.

[0042] In this embodiment, the pump device 1 is provided below the lower radial bearing 41b and the plurality of impellers 55, and includes an inducer 6 that sucks in the low-temperature fluid L.

[0043] This prevents the suction of the low-temperature fluid L from being obstructed by the lower radial bearing 41b or the impeller 55. Furthermore, vibrations caused by the suctioned low-temperature fluid L colliding with the lower radial bearing 41b or the impeller are suppressed. As a result, the pump device 1 can smoothly suction the low-temperature fluid L.

[0044] In this embodiment, the pump device 1 pumps the low-temperature fluid L at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h.

[0045] The pump device 1 can suitably suppress vibrations while pumping a low-temperature fluid at high pressure and high flow rate when pumping a low-temperature fluid at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h.

[0046] In this embodiment, the pump device 1 includes a thrust bearing 43 and a low-temperature fluid passage 60. The low-temperature fluid passage 60 has a main passage 61, a branch passage 64, and a balance pipe 65. The thrust bearing 43 is positioned above the upper radial bearing 41a. The low-temperature fluid passage 60 circulates the low-temperature fluid L. The main passage 161 circulates the low-temperature fluid L so that it passes through multiple impellers 55. The branch passage 64 branches off from the main passage 61 and circulates the low-temperature fluid L so that it passes through the upper radial bearing 41a, the lower radial bearing 41b, the electric motor 50, and the thrust bearing 43. The balance pipe 65 returns the low-temperature fluid L that has passed through the upper radial bearing 41a, the electric motor 50, and the thrust bearing 43 to the impeller 55 with intermediate pressure among the multiple impellers.

[0047] As a result, the flow of the low-temperature fluid L is branched from the impeller 55 and supplied to the upper radial bearing 41a, the lower radial bearing 41b, and the electric motor 50. The low-temperature fluid pump 20 can cool and lubricate the upper radial bearing 41a, the lower radial bearing 41b, and the electric motor 50 with this branched low-temperature fluid L. Furthermore, according to this embodiment, the low-temperature fluid pump 20 can return the low-temperature fluid L that has passed through the electric motor 50 and the upper radial bearing 41a to the intermediate-pressure impeller 55 via the balance pipe 165, thereby circulating it. In addition, the low-temperature fluid L is returned to the intermediate-pressure impeller 55. As a result, the gasification of the low-temperature fluid L is suppressed compared to when the low-pressure fluid L is returned to the lowest-pressure side of the impeller 55.

[0048] In this embodiment, the low-temperature fluid L is liquid hydrogen.

[0049] When the low-temperature fluid L is liquid hydrogen, the pump device 1 can effectively suppress vibrations while pumping the low-temperature fluid L at high pressure and high flow rate.

[0050] <Second Embodiment> (Pump system configuration) Hereinafter, the pump device 101 according to the second embodiment of this disclosure will be described with reference to Figure 2. Components common to the first embodiment will be given the same names and reference numerals, and their descriptions will be omitted as appropriate. In the second embodiment, the radial bearing 41 is a hydrostatic bearing, and the configuration of the low-temperature fluid passage 160 differs from that of the first embodiment.

[0051] (Low-temperature fluid channel) The low-temperature fluid flow path 160 includes a main flow path 161, a discharge section 162, a discharge pipe 163, a branch flow path 164, and a balance pipe 165. The main flow path 161 is shown with a solid line, the branch flow path 164 with a dashed line, and the balance pipe 165 with a dashed line.

[0052] (Main channel) The main flow path 161 circulates a cryogenic fluid L through multiple impellers 55. The main flow path 161 has a first main flow path 161a, a second main flow path 161b, and a third main flow path 161c. The first main flow path 161a guides the low-pressure cryogenic fluid L, which has been pressurized in the first-stage impeller 55a, to the second-stage impeller 55b. The first main flow path 161a is formed, for example, within the casing 30. The first main flow path 161a connects the first-stage impeller 55a and the second-stage impeller 55b so as to bypass the lower radial bearing 41b. The second main flow path 161b guides the intermediate-pressure cryogenic fluid L, which has been pressurized in the second-stage impeller 55b and the third-stage impeller 55c, to the fourth-stage impeller 55d. The second main flow path 161b is formed, for example, within the casing 30. The third main flow path 161c guides the high-pressure, low-temperature fluid L, which has been pressurized by the fourth-stage impeller 55d and the fifth-stage impeller 55e, to the discharge section 162, which will be described later. The third main flow path 161c is, for example, a pipe located radially outward from the outer circumferential surface of the casing 30. The third main flow path 161c may also be provided inside the casing 30.

[0053] (Discharge part) The discharge section 162 is formed on the lower surface of the upper flange. The third flow path is formed in a circular shape centered on axis O, for example, when viewed from below. High-pressure, low-temperature fluid L, which has been pressurized by a plurality of impellers 55, is supplied to the discharge section 162.

[0054] (discharge pipe) The discharge pipe 163 extends upward from the center of the discharge section 162. The discharge pipe 163 discharges the low-temperature fluid L from the discharge section 162 to the outside.

[0055] (Branching channel) The branch passage 164 branches off from the main passage 161 and allows the low-temperature fluid L to flow through the upper radial bearing 41a, the lower radial bearing 41b, the electric motor 50, and the thrust bearing 43. The branch passage 164 in this embodiment has a first branch passage 164a, a second branch passage 164b, a third branch passage 164c, a fourth branch passage 164d, and a fifth branch passage 164e. The first branch passage 164a supplies a portion of the low-temperature fluid L, which has been pressurized by the third-stage impeller 55c, to the lower radial bearing 41b. The first branch passage 164a is composed of, for example, a passage formed within the casing 30 and gaps between each member. The second branch passage 164b returns a portion of the low-temperature fluid L supplied from the fifth-stage impeller to the discharge section 162 back to the third-stage impeller 55c. The second branch channel 164b is composed of, for example, a passage formed within the casing 30 and gaps between the various components. The third branch channel 164c supplies a portion of the low-temperature fluid L supplied from the third stage impeller 55c to the fourth stage impeller 55d to the upper first seal mechanism 4 and the electric motor 50. The third branch channel 164c mainly supplies the low-temperature fluid L to the electric motor 50. The third branch channel 164c is composed of, for example, a passage formed within the casing 30 and gaps between the various components. In this embodiment, the third branch channel 164c is a gap between the various components within the casing 30, and the upstream end of the third branch channel 164c is the gap between the first seal mechanism 4 and the first outer seal portion 7. The fourth branch channel 164d and the fifth branch channel 164e each branch off from the first main channel 161a. The fourth branch channel 164d mainly supplies the low-temperature fluid L to the upper radial bearing 41a. The fifth branch channel 164e primarily supplies the cryogenic fluid L to the thrust bearing 43. Some of the cryogenic fluid L that has passed through the thrust bearing 43 is temporarily stored in the upper storage chamber 35. The fourth branch channel 164d and the fifth branch channel 164e are pipes positioned, for example, radially outward from the outer surface of the casing 30. The fourth branch channel 164d and the fifth branch channel 164e may also be provided inside the casing 30.

[0056] (Balanced piping) The balance pipe 165 returns the low-temperature fluid L that has passed through the upper radial bearing 41a, the motor 50, and the thrust bearing 43 to the intermediate-pressure impeller 55 among the multiple impellers 55 (in this embodiment, between the second-stage impeller 55b and the third-stage impeller 55c). The balance pipe 165 in this embodiment has a first balance pipe 165a, a second balance pipe 165b, and a third balance pipe 165c. The first balance pipe 165a returns the low-temperature fluid L that has leaked from the motor 50 and the upper radial bearing 41a to the area between the second-stage impeller 55b and the third-stage impeller 55c within the casing 30. The first balance pipe 165a mainly returns the low-temperature fluid L that has passed through the motor 50 to the intermediate-pressure impeller. The second balance pipe 165b returns the cryogenic fluid L leaking from the upper radial bearing 41a and thrust bearing 43 to the area between the second stage impeller 55b and the third stage impeller 55c within the casing 30. The second balance pipe 165b primarily returns the cryogenic fluid L that has passed through the upper radial bearing 41a to the impeller at intermediate pressure. The third balance pipe 165c returns the cryogenic fluid L leaking from the upper housing chamber 35 to the area between the second stage impeller 55b and the third stage impeller 55c within the casing 30. The third balance pipe 165c primarily returns the cryogenic fluid L that has passed through the thrust bearing 43 to the impeller 55 at intermediate pressure. The first balance pipe 165a, the second balance pipe 165b, and the third balance pipe 165c are, for example, pipes arranged radially outward from the outer circumferential surface of the casing 30. The first balance pipe 165a, the second balance pipe 165b, and the third balance pipe 165c may be provided inside the casing 30. Furthermore, the pressure difference in the space inside the casing 30 connected by each balance pipe 165 is reduced, and the thrust force in the axial direction O applied to the first seal mechanism 4 is suppressed.

[0057] (Flow of cold fluids) Next, the flow of the low-temperature fluid during the operation of the pump device 1 will be explained. As shown in Figure 2, when the electric motor 50 is driven, the rotating shaft 21 rotates, and the impeller 55 and inducer 6 fixed to the rotating shaft 21 rotate. At this time, the rotating shaft 21 is subjected to loads in the direction perpendicular to the rotating shaft 21 (radial direction) by the radial bearing 41. In addition, the rotating shaft 21 is subjected to loads in the direction of axis O by the thrust bearing 43.

[0058] The cryogenic fluid L in the liquid storage chamber 15 is drawn into the suction section 34 by the inducer 6 and pressurized in stages by multiple impellers 55. The cryogenic fluid L drawn into the suction section 34 by the inducer 6 is pressurized by the first stage impeller 55a. Subsequently, the cryogenic fluid L is sent to the second stage impeller 55b through the first main flow path 161a. The cryogenic fluid L is further pressurized by the second stage impeller 55b and the third stage impeller 55c to become an intermediate-pressure cryogenic fluid L. Most of the intermediate-pressure cryogenic fluid L is sent to the fourth stage impeller 55d through the second main flow path 161b. At this time, a portion of the cryogenic fluid L is sent from the third stage impeller 55c to the lower radial bearing 41b through the first branch flow path 164a. This cryogenic fluid L has a cooling function as a lubricant for the lower radial bearing 41b.

[0059] The cryogenic fluid L sent from the third stage impeller 55c to the fourth stage impeller 55d is further pressurized by the fourth stage impeller 55d and the fifth stage impeller 55e to become high-pressure cryogenic fluid L. Most of the high-pressure cryogenic fluid L is sent to the discharge section 162 through the third main flow path 161c and discharged to the outside of the pump device 101 through the discharge pipe 163. At this time, a portion of the cryogenic fluid L supplied from the fifth stage impeller 55e to the discharge section 162 is returned from the fifth stage impeller 55e to the third stage impeller 55c through the second branch flow path 164b. In addition, a portion of the cryogenic fluid L supplied to the fourth stage impeller 55d is supplied to the upper first seal mechanism 4 and the electric motor 50 through the third branch flow path 164c. Furthermore, a portion of the low-temperature fluid L flowing through the main channel 161 is supplied to the upper radial bearing 41a through the fourth branch channel 164d and to the thrust bearing 43 through the fifth branch channel 164e. As a result, the low-temperature fluid L has a cooling function as a lubricant for the first seal mechanism 4, the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43. The low-temperature fluid L supplied to the first seal mechanism 4, the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43 is returned to the intermediate-pressure impeller 55 (between the second-stage impeller 55b and the third-stage impeller 55c) through either the first balance pipe 165a, the second balance pipe 165b, or the third balance pipe 165c. The low-temperature fluid L returned to the intermediate-pressure impeller 55 is then gradually pressurized again by the intermediate-pressure impeller 55 and the high-pressure impeller 55.

[0060] (Effects and Benefits) The pump device 101 of the second embodiment can have the same configuration as the pump device 1 of the first embodiment and achieve the same effects.

[0061] In this embodiment, the branching channel 164 includes a third branching channel 164c that mainly supplies low-temperature fluid L to the electric motor 50, a fourth branching channel 164d that mainly supplies low-temperature fluid L to the upper radial bearing 41a, and a fifth branching channel 164e that mainly supplies low-temperature fluid L to the thrust bearing 43. Furthermore, the balance piping 165 includes a first balance piping 165a that mainly returns the low-temperature fluid L that has passed through the electric motor 50 to the impeller at intermediate pressure, a second balance piping 165b that mainly returns the low-temperature fluid L that has passed through the upper radial bearing 41a to the impeller at intermediate pressure, and a third balance piping 165c that mainly returns the low-temperature fluid L that has passed through the thrust bearing 43 to the impeller at intermediate pressure.

[0062] As a result, the pump device 101 can supply the low-temperature fluid L to the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43, and return the low-temperature fluid L from each of them to the impeller 55 at an intermediate pressure. Therefore, differences in the amount of low-temperature fluid L supplied and the temperature at the time of supply between the electric motor 50, the upper radial bearing 41a, and the thrust bearing 43 are suppressed.

[0063] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0064] <Note> The pump devices 1 and 101 described in each embodiment can be understood, for example, as follows.

[0065] (1) The pump devices 1, 101 according to the first embodiment include a rotating shaft 21 centered on an axis O extending in the vertical direction, an upper radial bearing 41a that rotatably supports the upper part of the rotating shaft 21 around the axis O, a lower radial bearing 41b that rotatably supports the lower part of the rotating shaft 21 around the axis O, a first seal mechanism 4 provided between the upper radial bearing 41a and the lower radial bearing 41b, through which the rotating shaft 21 is inserted, and a mechanism that rotates the rotating shaft 21 around the axis O between the upper radial bearing 41a and the first seal mechanism 4. The device comprises an electric motor 50, a plurality of impellers 55 located below the first seal mechanism 4, which pump a low-viscosity, low-temperature fluid L from below upward as the rotating shaft 21 rotates around its axis O, and a second seal mechanism 5 located between the lower radial bearing 41b and the first seal mechanism 4, through which the rotating shaft 21 is inserted. The plurality of impellers 55 include a pair of impellers 55 mounted back-to-back, and the second seal mechanism 5 is located at the mounting position of the pair of impellers 55 mounted back-to-back.

[0066] According to the above configuration, both the upper and lower ends of the rotating shaft 21 are supported by the upper radial bearing 41a and the lower radial bearing 41b. This suppresses vibration of the rotating shaft 21 as a whole. The motor 50 and impeller 55, which are sources of vibration, are positioned between the upper radial bearing 41a and the lower radial bearing 41b, and the first seal mechanism 4 is positioned between the motor 50 and the impeller 55. The first seal mechanism 4 is, for example, called a balance sleeve. Furthermore, a second seal mechanism 5 is provided at the mounting position of the pair of impellers 55 that are mounted back-to-back. The second seal mechanism 5 is, for example, called a center stage. The first seal mechanism 4 and the second seal mechanism 5 provide damping to the rotating shaft 21, further suppressing vibration of the rotating shaft 21. Therefore, the cryogenic fluid pump 20 of this embodiment can suppress vibration even when pumping high pressure and large flow rates.

[0067] (2) The pump devices 1, 101 of the second embodiment are the pump devices 1, 101 of (1), wherein the lower radial bearing 41b may be provided between two adjacent impellers 55.

[0068] The pump devices 1 and 101 can supply the low-temperature fluid L, which is pumped by the impeller 55, to the lower radial bearing 41b. This allows the pump devices 1 and 101 to cool and lubricate the lower radial bearing 41b at the same time.

[0069] (3) The pump devices 1, 101 of the third embodiment are the pump devices 1, 101 of (1) or (2), and may include an inducer 6 provided below the lower radial bearing 41b and the plurality of impellers 55 for drawing in the low-temperature fluid L.

[0070] This prevents the suction of the low-temperature fluid L from being obstructed by the lower radial bearing 41b or the impeller 55.

[0071] (4) The pump device 1, 101 of the fourth embodiment is any one of the pump devices 1, 101 of (1) to (3), which pumps the low-temperature fluid L at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h.

[0072] Pump devices 1 and 101 can suitably suppress vibrations while pumping low-temperature fluid at high pressure and high flow rate when pumping low-temperature fluid at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h.

[0073] (5) A fifth pump device 1, 101 is any one of the pump devices 1, 101 of (1) to (4), comprising a thrust bearing 43 positioned above the upper radial bearing 41a and a low-temperature fluid passage 160 through which the low-temperature fluid L flows, wherein the low-temperature fluid passage 160 may have main passages 61, 161 through which the low-temperature fluid L flows so that it passes through a plurality of impellers 55, branch passages 64, 164 branching from the main passages 61, 161 through which the low-temperature fluid L flows so that it passes through the upper radial bearing 41a, the lower radial bearing 41b, the electric motor 50, and the thrust bearing 43, and balance pipes 65, 165 that return the low-temperature fluid L that has passed through the upper radial bearing 41a, the electric motor 50, and the thrust bearing 43 to the impeller 55 with intermediate pressure among the plurality of impellers 55.

[0074] As a result, the flow of the low-temperature fluid L is branched from the impeller 55 and supplied to the upper radial bearing 41a, the lower radial bearing 41b, and the electric motor 50. The low-temperature fluid pump 20 can cool and lubricate the upper radial bearing 41a, the lower radial bearing 41b, and the electric motor 50 with this branched low-temperature fluid L. Furthermore, according to this embodiment, the low-temperature fluid pump 20 can return the low-temperature fluid L that has passed through the electric motor 50 and the upper radial bearing 41a to the intermediate-pressure impeller 55 via the balance pipe 165, thereby circulating it. Moreover, since the low-temperature fluid L is returned to the intermediate-pressure impeller 55, the gasification of the low-temperature fluid L is suppressed.

[0075] (6) The pump device 1, 101 of the sixth embodiment is any one of the pump devices 1, 101 of (1) to (5), and the low-temperature fluid L may be liquid hydrogen.

[0076] When the low-temperature fluid L is liquid hydrogen, the pump devices 1 and 101 can effectively suppress vibrations while pumping the low-temperature fluid L at high pressure and high flow rate. [Explanation of Symbols]

[0077] 1. Pumping device 2 Supply pipe 3. Gas discharge pipe 4. First sealing mechanism 5. Second sealing mechanism 6 Inducers 7. First outer seal section 8. Second outer seal section 10 Samp 11. Sump Unit 12 Outer flange 13 Upper flange 14 Mounting wall section 15 Liquid storage chamber 20 Cryogenic fluid pumps 21 Rotation axis 30 Casing 31 Motor casing 32 Pump casing 33 Flange section 33a Upper flange 33b Lower flange 34 Suction section 35 Upper containment chamber 40 Bearing device 41 Radial bearing 41a Upper radial bearing 41b Lower radial bearing 42 Thrust Discs 43 Thrust bearing 50 Electric motor 51 stata 52 rotors 55 Impeller 55a First stage impeller 55b Second stage impeller 55c 3rd stage impeller 55d 4th stage impeller 55e Fifth stage impeller 60 Low-temperature fluid channel 61 Main channel 61a First Main Channel 61b Second Main Channel 61c Third Main Channel 62 Discharge part 63 Discharge pipe 64 branch channels 64a First branch channel 64b Second branch channel 64c Third branch channel 65 Balanced piping 101 Pumping device 160 Low-temperature fluid channel 161 Main channel 161a First Main Channel 161b Second Main Channel 161c Third Main Channel 162 Discharge part 163 Discharge pipe 164 Branch Channel 164a First branch channel 164b Second branch channel 164c Third branch channel 164d Fourth branch channel 164e Fifth branch channel 165 Balanced piping 165a First balance piping 165b Second balance piping 165c Third balance pipe Dv vertical direction Dvu upper side DVD bottom L Cryogenic fluid O axis

Claims

1. An axis of rotation centered on an axis extending vertically, An upper radial bearing that supports the upper part of the rotating shaft so that it can rotate around the axis, A lower radial bearing that supports the lower part of the rotating shaft so that it can rotate around the axis, A first seal mechanism is provided between the upper radial bearing and the lower radial bearing, through which the rotating shaft is inserted, Between the upper radial bearing and the first seal mechanism, there is an electric motor that rotates the rotating shaft around its axis, A plurality of impellers are provided below the first sealing mechanism and, as the rotating shaft rotates around its axis, pump a low-viscosity, low-temperature fluid from below upward. A second seal mechanism is provided between the lower radial bearing and the first seal mechanism, through which the rotating shaft is inserted, Equipped with, The plurality of impellers include a pair of impellers mounted back-to-back, The second sealing mechanism is provided at the mounting position of the pair of impellers that are mounted back-to-back. Pumping device.

2. The lower radial bearing is provided between two adjacent impellers. The pump device according to claim 1.

3. The pump device according to claim 1 or 2, further comprising an inducer provided below the lower radial bearing and the plurality of impellers for drawing in the low-temperature fluid.

4. The aforementioned low-temperature fluid is pumped at a pressure of 0.5 to 3.0 MPa and a flow rate of 1.5 to 10.0 t / h. The pump device according to claim 1 or 2.

5. A thrust bearing positioned above the aforementioned upper radial bearing, A low-temperature fluid channel through which the low-temperature fluid flows, Equipped with, The low-temperature fluid channel is A main channel through which the low-temperature fluid is circulated so as to pass through multiple impellers, A branch channel that branches off from the main channel and allows the low-temperature fluid to flow through the upper radial bearing, the lower radial bearing, the electric motor, and the thrust bearing, A balance pipe returns the low-temperature fluid, which has passed through the upper radial bearing, the electric motor, and the thrust bearing, to the impeller with the intermediate pressure among the plurality of impellers. Having, The pump device according to claim 1 or 2.

6. The low-temperature fluid is liquid hydrogen. The pump device according to claim 1 or 2.

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