centrifugal pump

Abstract

A centrifugal pump is provided that can pump a liquid at extremely low or high temperatures and can be test-run at room temperature. [Solution] A centrifugal pump 1 according to the present invention comprises an impeller 4, a rotating shaft 61, a bearing 7, a bearing support member 8, and elastic bodies 9a-9h. The bearing has an outer peripheral surface 7S. The bearing support member has an inner peripheral surface 8S and recesses Ra-Rh. The bearing and bearing support member are made of metal. The inner peripheral surface is disposed opposite the outer peripheral surface, and the elastic bodies are disposed in the recesses. At a first temperature, the inner peripheral surface abuts against the outer peripheral surface so that a predetermined fit is achieved between the bearing and the bearing support member, and the elastic bodies are pressed by the outer peripheral surface radially outward from the rotating shaft. At a second temperature, the elastic bodies protrude radially inward beyond the inner peripheral surface to support the bearing.

Description

[Technical Field]

[0001] The present invention relates to a centrifugal pump. [Background technology]

[0002] BACKGROUND ART A centrifugal pump including a rotating shaft, a bearing, and a housing is known (see, for example, Patent Document 1).

[0003] The rotating shaft is supported by a bearing. The bearing is supported (held) by a part of the housing or a member that supports the bearing (hereinafter collectively referred to as the "bearing support member"). The bearing support member is disposed radially outward of the bearing of the rotating shaft. Both the bearing and the bearing support member are made of metal. When the centrifugal pump is operating, both the bearing and the bearing support member are in contact with the pumped liquid flowing through the centrifugal pump.

[0004] For example, when the pumped fluid flowing through a centrifugal pump is a cryogenic liquid (e.g., -230°C), the bearings and bearing support members are cooled by the pumped fluid. As a result, the bearings and bearing support members contract. On the other hand, when the pumped fluid flowing through a centrifugal pump is a high-temperature liquid (e.g., 150°C), the bearings and bearing support members are heated by the pumped fluid. As a result, the bearings and bearing support members expand. If the bearings and bearing support members are made of metals with the same thermal expansion coefficient, the fit between the components remains constant regardless of the temperature of the pumped fluid (cryogenic or high). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-094794 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the bearing and the bearing support member are made of metals with different thermal expansion coefficients, the fit between the components changes depending on the temperature of the pumped fluid. Therefore, the bearing support member is designed to ensure that the centrifugal pump operates normally (i.e., the bearing support member can reliably support the bearing) at the operating temperatures (cryogenic and high temperatures) of the centrifugal pump. For example, when a centrifugal pump is designed to operate at cryogenic temperatures, a metal with a higher thermal expansion coefficient than the metal constituting the bearing is selected for the bearing support member. Therefore, at the temperature (cryogenic temperatures) when the centrifugal pump delivers fluid, the fit between the components is appropriate, and the bearing support member reliably supports the bearing. On the other hand, at temperatures during the manufacture and maintenance of the centrifugal pump (e.g., room temperature: 20°C ± 15°C), a gap may form between the bearing and the bearing support member. Furthermore, when a centrifugal pump is designed to operate at high temperatures, a metal with a lower thermal expansion coefficient than the metal constituting the bearing is selected for the bearing support member. Therefore, at the high temperatures during the pumping operation, the fitting between the components is proper, and the bearing support member securely supports the bearing. However, at the temperatures during the manufacturing and maintenance of the centrifugal pump, a gap may form between the bearing and the bearing support member. When the bearing and the bearing support member are made of metals with different thermal expansion coefficients, a gap forms between the bearing and the bearing support member during manufacturing and maintenance. This makes it difficult to perform a test run of the centrifugal pump.

[0007] An object of the present invention is to provide a centrifugal pump that can pump a liquid at extremely low or high temperatures and can be test-run at room temperature. [Means for solving the problem]

[0008] A centrifugal pump according to one embodiment of the present invention is a centrifugal pump used at a first temperature, comprising: an impeller that sucks in a pumped liquid and discharges the pumped liquid; a rotary shaft that rotates the impeller; a bearing that supports the rotary shaft; a bearing support member that is disposed radially outward of the bearing in the radial direction of the rotary shaft and supports the bearing; and three or more elastic bodies that are sandwiched between the bearing and the bearing support member, wherein the bearing has a cylindrical outer peripheral surface, and the bearing support member has a cylindrical inner peripheral surface and three or more recesses that are disposed on the inner peripheral surface in the circumferential direction of the inner peripheral surface, The bearing and the bearing support member are each made of metal, the inner circumferential surface is arranged to face the outer circumferential surface, and each of the multiple elastic bodies is arranged in each of the multiple recesses so as to abut against the outer circumferential surface, and at the first temperature, the inner circumferential surface abuts against the outer circumferential surface so that the fit between the bearing and the bearing support member is a predetermined fit, and each of the elastic bodies is pressed radially outward by the outer circumferential surface, and at a second temperature different from the first temperature, each of the elastic bodies protrudes radially inward beyond the inner circumferential surface and supports the bearing. [Effects of the Invention]

[0009] The present invention can provide a centrifugal pump that can pump a liquid at extremely low or high temperatures and can be test-run at room temperature. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a centrifugal pump according to an embodiment of the present invention; [Figure 2] FIG. 2 is a partially enlarged schematic cross-sectional view of part A in FIG. [Figure 3] FIG. 4 is a schematic front view of the vicinity of a bearing of the centrifugal pump at a second temperature. [Figure 4] 4 is a partially enlarged schematic front view of the vicinity of the boundary between the bearing of the centrifugal pump and the bearing support member of the centrifugal pump in FIG. 3. FIG. [Figure 5]FIG. 3 is a schematic front view of the bearing and its vicinity at a first temperature. [Figure 6] 6 is a partially enlarged schematic front view of the vicinity of the boundary between the bearing and the bearing support member in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a centrifugal pump according to the present invention (hereinafter referred to as "the pump") will be described below with reference to the drawings. In each drawing, the same members and elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions of each element may be exaggerated for the sake of convenience, and are not limited to the proportions shown in each drawing.

[0012] In the following description, each temperature (cryogenic, high, room temperature) refers to the temperature of the fluid in contact with each component of the pump (particularly the bearings and bearing support components described below). That is, for example, when the pump is operating (pumping), the fluid is the pumped liquid. Also, when the components of the pump are not in contact with the liquid, for example, due to maintenance, the fluid is the gas in contact with the components (e.g., outside air in the installation environment of the pump, or nitrogen gas or helium gas used for purging). Each component of the pump has approximately the same temperature as the fluid it is in contact with. That is, for example, the temperature of each component is cryogenic when the fluid is a cryogenic liquid, and room temperature when the fluid is a gas at room temperature (20°C ± 15°C).

[0013] ●Configuration of this pump First, the construction of the pump will be described below.

[0014] In the following description, the extremely low temperature is an example of the first temperature in the present invention, and the room temperature is an example of the second temperature in the present invention.

[0015] FIG. 1 is a schematic cross-sectional view of the pump, showing an embodiment of the pump. In the figure, the flow of the pumped fluid is indicated by white arrows.

[0016] This pump 1 is used to pump a pumped liquid. In this embodiment, the "pumped liquid" is a cryogenic liquid. The "cryogenic liquid" is, for example, liquid hydrogen. That is, in this embodiment, the "cryogenic temperature" is, for example, -253°C. This pump 1 includes a pump section 2, a motor section 3, and an impeller 4.

[0017] In the present invention, the cryogenic liquid may be liquid nitrogen, liquid helium, or the like.

[0018] In the following description, the "forward direction" refers to the direction in which the impeller 4 is disposed relative to the motor unit 3, and the "rearward direction" refers to the opposite direction to the forward direction. In other words, in the axial direction of the rotating shaft 61 described below, the "forward direction" refers to the direction in which the front end portion 61a of the rotating shaft 61 is oriented, and the "rearward direction" refers to the opposite direction to the forward direction.

[0019] The forward direction is an example of a first direction in the present invention, and the rearward direction is an example of a second direction in the present invention.

[0020] The pump unit 2 sucks in and discharges the pumped fluid and includes a housing 21, a pump chamber 22, a suction pipe 23, a discharge pipe 24, and an internal flow path 25.

[0021] The housing 21 accommodates the motor unit 3. The housing 21 defines a pump chamber 22 and an internal flow path 25. The housing 21 is made of a metal such as an aluminum alloy. The front end of the housing 21 extends cylindrically forward to form a suction pipe 23. The rear end of the housing 21 extends cylindrically rearward to form a discharge pipe 24. An internal flow path 25 is formed between the housing 21 and the motor unit 3 (housing 5, described later) along the front-to-rear direction. The internal flow path 25 is in communication with the pump chamber 22 and the discharge pipe 24. That is, the housing 21 defines the pump chamber 22, the suction pipe 23, the discharge pipe 24, and the internal flow path 25.

[0022] The pump chamber 22 accommodates the impeller 4 .

[0023] The suction pipe 23 is a flow path for the pumped liquid to be sucked into the pump chamber 22.

[0024] The discharge pipe 24 is a flow path for the pumped liquid discharged from the pump chamber 22 .

[0025] The internal flow path 25 is a flow path through which the pumped liquid sucked into the pump chamber 22 from the suction pipe 23 is guided to the discharge pipe 24 .

[0026] The motor unit 3 is driven under predetermined driving conditions to rotate the impeller 4 in the pump chamber 22. The motor unit 3 is housed in a housing 21. The specific configuration of the motor unit 3 will be described later.

[0027] The impeller 4 is attached to a front end 61a of a rotary shaft 61, which will be described later, and rotates with the rotation of the rotary shaft 61. That is, the impeller 4 rotates with the rotation of the motor unit 3. As the impeller 4 rotates, the pumped fluid that has been sucked into the pump chamber 22 from the suction pipe 23 is discharged via the internal flow path 25 and the discharge pipe 24. In other words, the impeller 4 sucks in the pumped fluid and discharges it.

[0028] ●Motor section configuration Next, the configuration of the motor unit 3 will be described below.

[0029] FIG. 2 is a partially enlarged schematic cross-sectional view of part A in FIG. 3 is a schematic front view of the vicinity of the bearing 7 at the second temperature. For ease of explanation, these figures show a simplified view of the vicinity of the bearing 7. In the following explanation, FIG. 1 will be referred to as well as FIGS. 2 and 3 as appropriate.

[0030] The motor section 3 includes a housing 5, a motor 6, bearings 7a and 7b, bearing support members 8a and 8b, and a plurality of (eight in this embodiment) elastic bodies 9a, 9b, 9c, 9d, 9e, 9f, 9g, and 9h.

[0031] In the following description, when the bearings 7a and 7b are not particularly distinguished from each other, the bearings 7a and 7b are collectively referred to as the bearings 7.

[0032] In the following description, when the bearing support members 8a and 8b are not particularly distinguished from each other, the bearing support members 8a and 8b are collectively referred to as the bearing support member 8.

[0033] Furthermore, in the following description, when the elastic bodies 9a to 9h are not particularly distinguished from one another, the elastic bodies 9a to 9h are collectively referred to as the elastic body 9.

[0034] The housing 5 defines a motor chamber 51. The housing 5 is made of a metal such as an aluminum alloy. The housing 5 includes the motor chamber 51 and two liquid inlets 52 and 53.

[0035] The motor chamber 51 accommodates a rotary shaft 61, a rotor 62, a stator 63, a bearing 7, a bearing support member 8, and an elastic body 9.

[0036] The liquid inlets 52, 53 are holes that penetrate the housing 5. The liquid inlets 52, 53 communicate with the internal flow path 25 and the motor chamber 51, and introduce the pumped liquid into the motor chamber 51. The motor chamber 51 is filled with the introduced pumped liquid. The liquid inlets 52, 53 are located, for example, in the front portion of the housing 5.

[0037] In the present invention, the liquid inlets 52 and 53 may be disposed in the rear or central part of the housing 5.

[0038] In the present invention, the number of the liquid inlets 52 and 53 is not limited to two, and may be any number that allows the pumped liquid to be introduced into the motor chamber 51 .

[0039] Furthermore, in the present invention, the housing 5 does not necessarily have to include the liquid inlets 52 and 53. In this case, for example, the pumped liquid may be introduced into the motor chamber 51 via the bearings 7a and 7b.

[0040] The motor 6 includes a rotating shaft 61 , a rotor 62 , and a stator 63 .

[0041] The rotating shaft 61 rotates due to the rotation of the rotor 62 and transmits rotational power to the impeller 4. In other words, the rotating shaft 61 rotates the impeller 4. The rotating shaft 61 is cylindrical in shape. The rotating shaft 61 is made of a metal such as stainless steel. The rotating shaft 61 is inserted through the rotor 62 and fixed to the rotor 62. A front end 61a of the rotating shaft 61 protrudes into the pump chamber 22.

[0042] In the following description, the "axial direction" refers to the direction along the rotation axis of the rotating shaft 61 (front-to-back direction), the "radial direction" refers to the radial direction of the rotating shaft 61, and the "circumferential direction" refers to the circumferential direction of the rotating shaft 61.

[0043] The rotor 62 rotates due to the rotating magnetic field generated by the stator 63. The rotor 62 has a cylindrical shape that extends along the axial direction.

[0044] The stator 63 generates a rotating magnetic field that rotates the rotor 62 (rotating shaft 61). The stator 63 has a cylindrical shape that extends along the axial direction.

[0045] The bearings 7 support the rotating shaft 61 so that it can rotate freely. The bearings 7 are, for example, known rolling bearings. The bearings 7 are cylindrical in shape along the axial direction. The bearings 7 are made of metal such as stainless steel. The bearings 7a support the front part of the rotating shaft 61, and the bearings 7b support the rear part of the rotating shaft 61. In the radial direction, the bearings 7 are arranged outward from the rotating shaft 61. The bearings 7 have an outer circumferential surface 7S.

[0046] The outer peripheral surface 7S has a cylindrical shape extending along the axial direction.

[0047] The bearing support member 8 is attached to the housing 5 and supports the bearing 7. The bearing support member 8 is, for example, a bearing holder. The bearing support member 8 has a cylindrical shape along the axial direction. The bearing support member 8 is made of a metal such as an aluminum alloy. In this embodiment, the thermal expansion coefficient of the metal constituting the bearing support member 8 is greater than the thermal expansion coefficient of the metal constituting the bearing 7. In other words, the bearing 7 and the bearing support member 8 are made of metals having different thermal expansion coefficients. At cryogenic temperatures, the inner diameter 8r of the bearing support member 8 is substantially the same as the outer diameter 7r of the bearing 7 (see FIG. 5 ). When the bearing 7 is not disposed radially inside the bearing support member 8, the inner diameter 8r of the bearing support member 8 is smaller than the outer diameter 7r of the bearing 7 at cryogenic temperatures. In other words, the fitting between the bearing 7 and the bearing support member 8 is predetermined at cryogenic temperatures. The "predetermined fit" is a fit to the extent that the bearing 7 is tightly fitted into the bearing support member 8 (to the extent that the bearing support member 8 can properly support the bearing 7). At room temperature, the inner diameter 8r of the bearing support member 8 is larger than the outer diameter 7r of the bearing 7 (see FIG. 3). In other words, a slight gap is generated between the bearing 7 and the bearing support member 8. The bearing support member 8a supports the bearing 7a, and the bearing support member 8b supports the bearing 7b. In the radial direction, the bearing support member 8a is disposed outward of the bearing 7a, and the bearing support member 8b is disposed outward of the bearing 7b. The bearing support member 8 has an inner circumferential surface 8S and a plurality of (eight in this embodiment) recesses Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh.

[0048] In the following description, when the recesses Ra to Rh are not particularly distinguished from one another, the recesses Ra to Rh are collectively referred to as recesses R.

[0049] The inner peripheral surface 8S has a cylindrical shape extending along the axial direction, and is disposed so as to face the outer peripheral surface 7S in the radial direction.

[0050] FIG. 4 is a partially enlarged schematic front view of the vicinity of the boundary between the bearing 7 and the bearing support member 8 in FIG. For ease of explanation, the drawing shows in a simplified manner the vicinity of the boundary between the bearing 7 and the bearing support member 8. In the following description, FIGS. 1 to 3 will be referred to as appropriate together with FIG.

[0051] The recesses Ra to Rh are arranged at equal intervals on the inner peripheral surface 8S in the circumferential direction (i.e., the circumferential direction of the inner peripheral surface 8S). The recesses R are shaped like grooves extending along the axial direction. When viewed in the axial direction, the recesses R are substantially U-shaped. The recesses R have a first end R1, a second end R2, and open ends R3 and R4.

[0052] In the present invention, the number of recesses R is not limited to "8" as long as it is three or more.

[0053] Furthermore, the shape of the recess R when viewed in the axial direction is not limited to a U-shape. That is, for example, the shape of the recess R when viewed in the axial direction may be any shape that can accommodate the elastic body 9.

[0054] The first end R1 is the front end of the recess R. The first end R1 is open toward the front.

[0055] The second end R2 is the rear end of the recess R. The second end R2 is open toward the rear.

[0056] In the present invention, at least one of the first end R1 and the second end R2 does not have to be open in the front-rear direction.

[0057] When viewed in the axial direction, the opening ends R3 and R4 are radially inward ends of the recessed portion R. When viewed in the axial direction, the opening ends R3 and R4 are located at the boundary between the inner circumferential surface 8S and the recessed portion R.

[0058] Here, when the radial direction passing through the center P1 of the recess R in the circumferential direction of the inner surface 8S is a specific radial direction D1, in a direction perpendicular to the specific radial direction D1 and the axial direction (hereinafter referred to as the "perpendicular direction"), the length RL1 of the opening ends R3, R4 of the recess R arranged in the specific radial direction D1 is smaller than the outer diameter 9r of the elastic body 9.

[0059] The elastic bodies 9 expand and contract in the radial direction to press against the bearing 7. The elastic bodies 9 are, for example, coil springs. The elastic bodies 9 are made of, for example, a metal such as stainless steel. Each of the elastic bodies 9a to 9h is disposed in a corresponding one of the recesses Ra to Rh so that the free length direction of the elastic body 9 is along the axial direction. That is, in the radial direction, each of the elastic bodies 9a to 9h is sandwiched between the bearing 7 and the bearing support member 8. Each of the elastic bodies 9a to 9h abuts against the outer circumferential surface 7S and the corresponding recess Ra to Rh (bearing support member 8).

[0060] Here, the outer diameter 9r of the elastic body 9 is larger than the depth (length in the radial direction) RL2 of the recessed portion R. The outer diameter 9r of the elastic body 9 is smaller than the width (length in the perpendicular direction) RL3 of the recessed portion R. Therefore, at room temperature, the elastic body 9 is accommodated in the recessed portion R with only a portion of the elastic body 9 protruding radially inward beyond the inner circumferential surface 8S.

[0061] In the present invention, the number of elastic bodies 9 is not limited to "8" as long as it is three or more (the same number as the number of recesses R).

[0062] ● Supporting the bearing at the first temperature Next, support of the bearing 7 when the temperatures of the bearing 7 and the bearing support member 8 are at the first temperature (extremely low temperature) will be described below. The temperatures of the bearing 7 and the bearing support member 8 are at the first temperature when the pump 1 is operating.

[0063] The following explanation is an example when the pump 1 is pumping pumped liquid (when the pump 1 is operating). When the pump 1 is operating, the pumped liquid is sucked into the pump chamber 22 from the suction pipe 23 as the impeller 4 rotates. The sucked pumped liquid passes through the liquid inlets 52, 53 and the bearings 7a, 7b and is introduced into the motor chamber 51. In other words, the motor chamber 51 is filled with the pumped liquid. Therefore, the bearing 7 and the bearing support member 8 are in contact with the pumped liquid and are cooled to a first temperature (extremely low temperature).

[0064] FIG. 5 is a schematic front view of the vicinity of the bearing 7 at the first temperature. FIG. 6 is a partially enlarged schematic front view of the vicinity of the boundary between the bearing 7 and the bearing support member 8 in FIG. For the sake of convenience, these figures show the vicinity of the boundary between the bearing 7 and the bearing support member 8 in a simplified manner.

[0065] In the following description, FIGS. 1 to 4 will be referred to as appropriate along with FIGS. 5 and 6.

[0066] The bearing 7 and the bearing support member 8 are cooled to a first temperature by the treated fluid. As a result, the bearing 7 and the bearing support member 8 contract. As described above, the thermal expansion coefficient of the bearing support member 8 is greater than that of the bearing 7. Therefore, the bearing support member 8 contracts more than the bearing 7. At this time, each of the elastic bodies 9a to 9h is pressed radially outward by the outer circumferential surface 7S in accordance with the amount of contraction of the bearing 7 and the bearing support member 8.

[0067] Here, the bearing support member 8 is designed so that the fit between the bearing 7 and the bearing support member 8 becomes a predetermined fit when the temperature of the bearing support member 8 becomes substantially the same as the temperature of the handled fluid (first temperature: cryogenic temperature). Therefore, when the temperature of the bearing 7 and the bearing support member 8 becomes substantially the same as the temperature of the handled fluid, the inner circumferential surface 8S abuts against the outer circumferential surface 7S and presses the outer circumferential surface 7S radially inward. As a result, the bearing 7 is fixed to the bearing support member 8 by an external force (a force acting radially inward) from the bearing support member 8. At this time, each of the elastic bodies 9a-9h is pressed radially outward by the outer circumferential surface 7S and is accommodated inside the corresponding recesses Ra-Rh. In this way, at the first temperature (cryogenic temperature), the bearing 7 is supported by the bearing support member 8, which is a rigid metal body, with a predetermined fit. In other words, the bearing 7 is properly supported by the bearing support member 8.

[0068] ● Supporting bearings at the second temperature Next, support of bearing 7 when the temperatures of bearing 7 and bearing support member 8 are at the second temperature (room temperature) will be described below. The temperatures of bearing 7 and bearing support member 8 are at the second temperature when pump 1 is not pumping the pumped liquid (for example, during maintenance of pump 1). In the following description, Figures 1 to 6 will be referenced as appropriate.

[0069] The following explanation is an example of maintenance of the pump 1. During maintenance of the pump 1, outside air in the installation environment of the pump 1 is introduced into the housing 5, and the pumped liquid inside the housing 5 is discharged to the outside of the housing 5. Therefore, the bearing 7 and the bearing support member 8 are in contact with the outside air (gas). Therefore, the temperature of the bearing 7 and the bearing support member 8 is approximately the same as the temperature of the gas they are in contact with (second temperature: room temperature). In other words, during maintenance of the pump 1, the bearing 7 and the bearing support member 8 are heated from the first temperature (cryogenic temperature) to the second temperature (room temperature). As a result, the bearing 7 and the bearing support member 8 expand.

[0070] As described above, the thermal expansion coefficient of the bearing support member 8 is greater than that of the bearing 7. Therefore, the bearing support member 8 expands more than the bearing 7. At this time, a small gap is generated between the bearing 7 and the bearing support member 8.

[0071] When a small gap is generated between the bearing 7 and the bearing support member 8, a portion of the elastic body 9 protrudes radially inward from the inner circumferential surface 8S due to the restoring force (elastic force) of the elastic body 9. At this time, the elastic body 9 is still pressed radially outward by the outer circumferential surface 7S (bearing 7). Therefore, the bearing 7 is pressed radially inward by the restoring force (elastic force) of the elastic body 9. Generally, the restoring force in the direction perpendicular to the free length direction of the elastic body 9 is greater than the restoring force in the free length direction of the elastic body 9. Therefore, the bearing 7 is pressed by the strong restoring force of the elastic body 9. As a result, at the second temperature, the bearing 7 is supported (sandwiched) by the elastic body 9, not by the bearing support member 8. As a result, the inner circumferential surface 8S is separated from the outer circumferential surface 7S over the entire circumferential direction. At this time, the bearing support member 8 and the elastic body 9 are designed to be able to support the bearing 7 with a force that allows for a simple trial run of the pump 1 (for example, operation without pumping liquid and at low speed).

[0072] Thus, at the first temperature (cryogenic temperature), the bearing 7 and the bearing support member 8 are cooled by the pumped liquid and contract. The fit between the bearing 7 and the bearing support member 8 is designed to provide a predetermined fit at the first temperature (cryogenic temperature). That is, the bearing 7 is fixed at an appropriate position relative to the bearing support member 8 in the radial direction (a position where the centers of the rotating shaft 61, the bearing 7, and the bearing support member 8 are aligned when viewed in the axial direction). Therefore, the pump 1 operates normally as designed at the first temperature (cryogenic temperature). That is, the pump 1 is capable of pumping the pumped liquid at the first temperature (cryogenic temperature). That is, the pump 1 is usable at the first temperature. Furthermore, at the second temperature (normal temperature), a gap is generated between the bearing 7 and the bearing support member 8. That is, the inner circumferential surface 8S is spaced from the outer circumferential surface 7S. At this time, the bearing 7 is pressed radially inward by the restoring force (elastic force) of the elastic body 9 sandwiched between the bearing 7 and the bearing support member 8. In other words, the bearing 7 is simply fixed (maintained) in an appropriate position relative to the bearing support member 8 in the radial direction. Therefore, test operation of the pump 1 is possible at the second temperature (room temperature).

[0073] Summary According to the embodiment described above, the pump 1 is used at a first temperature (cryogenic temperature). The pump 1 includes an impeller 4, a rotating shaft 61, a bearing 7, a bearing support member 8, and a plurality of elastic bodies 9a-9h. The bearing support member 8 is disposed radially outward of the bearing 7 and supports the bearing 7. The elastic body 9 is sandwiched between the bearing 7 and the bearing support member 8. The bearing 7 includes a cylindrical outer peripheral surface 7S. The bearing support member 8 includes a cylindrical inner peripheral surface 8S and a plurality of recesses Ra-Rh. Each of the recesses Ra-Rh is disposed on the inner peripheral surface 8S in the circumferential direction. The bearing 7 and the bearing support member 8 are made of metals having different thermal expansion coefficients. The thermal expansion coefficient of the bearing support member 8 is greater than that of the bearing 7. The inner peripheral surface 8S is disposed to face the outer peripheral surface 7S. Each of the elastic bodies 9a-9h is disposed in a corresponding one of the recesses Ra-Rh so as to abut against the outer peripheral surface 7S of the bearing 7. At a first temperature, the inner peripheral surface 8S abuts against the outer peripheral surface 7S so that a predetermined fit is achieved between the bearing 7 and the bearing support member 8. Each of the elastic bodies 9a-9h is pressed radially outward from the rotating shaft 61 by the outer peripheral surface 7S. At a second temperature (room temperature) different from the first temperature, each of the elastic bodies 9a-9h protrudes radially inward from the inner peripheral surface 8S of the rotating shaft 61 to support the bearing 7. With this configuration, at the first temperature, the fit between the bearing 7 and the bearing support member 8 is a predetermined fit (tight fit). At this time, the bearing support member 8 properly supports the bearing 7. Therefore, the pump 1 is capable of pumping the pumped fluid at the first temperature. On the other hand, at the second temperature, each of the elastic bodies 9a to 9h protrudes radially inward beyond the inner circumferential surface 8S, and simply supports the bearing 7. Therefore, in the pump 1, a test run of the centrifugal pump is possible at the second temperature.

[0074] Furthermore, according to the embodiment described above, the shape of the recess R is a groove that is aligned with the axial direction of the rotating shaft 61. The elastic body 9 is a coil spring, and is disposed in the recess R so that the free length direction of the elastic body 9 is aligned with the axial direction. In general, the restoring force of the elastic body 9 in a direction perpendicular to the free length direction is greater than the restoring force of the elastic body 9 in the free length direction. Therefore, according to this configuration, at the second temperature (room temperature), the bearing 7 is appropriately fixed (maintained) at an appropriate position relative to the bearing support member 8 in the radial direction.

[0075] Furthermore, according to the embodiment described above, the recess R has a first end R1 and a second end R2. In the recess R, the first end R1 is disposed on the front side. In the recess R, the second end R2 is disposed on the rear side. The first end R1 and the second end R2 are open in the axial direction. With this configuration, a user of the pump 1 (hereinafter referred to as the "user") can place the elastic body 9 in the recess R via the first end R1 and the second end R2. In other words, the user can insert the elastic body 9 into the recess R from the axial side. This makes assembly of the pump 1 easier.

[0076] Furthermore, according to the embodiment described above, the length RL1 of the open ends R3, R4 of the recess R in the orthogonal direction perpendicular to the specific radial direction D1 and the axial direction is smaller than the outer diameter 9r of the elastic body 9. With this configuration, when the rotating shaft 61 is arranged parallel to the horizontal direction, the elastic body 9 will not fall out of the recess R even if the user pulls out the bearing 7 from the bearing support member 8. This makes assembly of the pump 1 easier.

[0077] ●Other embodiments● In the embodiment described above (hereinafter referred to as the "first embodiment"), the treated liquid is a cryogenic liquid. Alternatively, the treated liquid in the present invention may be a high-temperature liquid (e.g., 150°C). In this case, the relationship between the thermal expansion coefficients of the bearing 7 and the bearing support member 8 is reversed from that in the first embodiment. That is, the thermal expansion coefficient of the bearing support member 8 is smaller than that of the bearing 7. At this time, the bearing 7 and the bearing support member 8 are heated to a first temperature (high temperature) by the treated liquid. As a result, the bearing 7 and the bearing support member 8 expand. Because the thermal expansion coefficient of the bearing support member 8 is smaller than that of the bearing 7, the bearing 7 expands more than the bearing support member 8. At this time, each of the elastic bodies 9a to 9h is pressed radially outward by the outer circumferential surface 7S in accordance with the amount of expansion of the bearing 7 and the bearing support member 8. In this case, the high temperature is an example of the first temperature in the present invention.

[0078] Here, the bearing support member 8 is designed so that the fit between the bearing 7 and the bearing support member 8 becomes a predetermined fit when the temperature of the bearing support member 8 becomes substantially the same as the temperature of the handled fluid (first temperature: high temperature). Therefore, when the temperatures of the bearing 7 and the bearing support member 8 become substantially the same as the temperature of the handled fluid (first temperature), the inner circumferential surface 8S abuts against the outer circumferential surface 7S and presses the outer circumferential surface 7S radially inward. As a result, the bearing 7 is fixed by an external force (a force acting radially inward) from the bearing support member 8. At this time, each of the elastic bodies 9a to 9h is pressed radially outward by the outer circumferential surface 7S and is accommodated inside the recess R. In this way, at the first temperature (high temperature), the bearing 7 is supported by the bearing support member 8, which is a rigid metal body, with a predetermined fit. In other words, the bearing 7 is appropriately supported by the bearing support member 8.

[0079] Thus, at the first temperature (high temperature), the bearing 7 and bearing support member 8 are heated by the pumped fluid and expand. The fit between the bearing 7 and bearing support member 8 is designed to provide a predetermined fit at the first temperature (high temperature). That is, the bearing 7 is fixed at an appropriate position relative to the bearing support member 8 in the radial direction (a position where the centers of the rotating shaft 61, bearing 7, and bearing support member 8 are aligned when viewed in the axial direction). Therefore, the pump 1 operates normally as designed at the first temperature (high temperature). That is, the pump 1 is capable of pumping the pumped fluid at the first temperature (high temperature). That is, the pump 1 is usable at the first temperature. Furthermore, at the second temperature (normal temperature), a gap is generated between the bearing 7 and bearing support member 8. That is, the inner circumferential surface 8S is spaced from the outer circumferential surface 7S. At this time, the bearing 7 is pressed radially inward by the restoring force (elastic force) of the elastic body 9 sandwiched between the bearing 7 and the bearing support member 8. In other words, the bearing 7 is simply fixed (maintained) in an appropriate position relative to the bearing support member 8 in the radial direction. Therefore, test operation of the pump 1 is possible at the second temperature (room temperature).

[0080] In the first embodiment described above, the bearing 7 and the bearing support member 8 are made of metals with different thermal expansion coefficients. Alternatively, the bearing 7a and the bearing support member 8a in the present invention may be made of metals with the same thermal expansion coefficient. With this configuration, the fit between the bearing 7a and the bearing support member 8a remains constant regardless of the temperature (cryogenic or high) of the handled fluid. That is, the front portion of the rotating shaft 61 is fixed in a predetermined position. Even if the rotating shaft 61 thermally expands and contracts, the position of the front portion of the rotating shaft 61 remains fixed. On the other hand, at the second temperature, a gap is generated between the bearing 7b and the bearing support member 8b, allowing the rear portion of the rotating shaft 61 to expand and contract in the axial direction. Therefore, even if the temperature changes between the first temperature and the second temperature, the impeller 4, which is located on the front side of the rotating shaft 61, is unlikely to shift in position. In this configuration, the bearing 7a is an example of a second bearing in the present invention. The bearing support member 8a is an example of a second bearing support member in the present invention.

[0081] Furthermore, in the first embodiment described above, the bearing 7 and the bearing support member 8 are made of metals with different thermal expansion coefficients. Alternatively, the bearing 7 and the bearing support member 8 in the present invention may be made of metals with the same thermal expansion coefficient. In this case, when the centrifugal pump is operating (when pumped liquid is being pumped), the bearing 7 generates heat as the rotating shaft 61 rotates at a predetermined rotation speed (a rotation speed that can pump a desired amount of pumped liquid) or higher. At this time, the temperature of the bearing 7 is higher than the temperature of the bearing support member 8. As a result, the bearing 7 expands more than the bearing support member 8 in accordance with the temperature difference between the bearing 7 and the bearing support member 8. At this time, the bearing support member 8 may be designed to utilize the expansion of the bearing 7 due to heat generation from the bearing 7 to achieve a predetermined fit (tight fit) between the bearing 7 and the bearing support member 8. That is, for example, at a first temperature (extremely low temperature), the bearing 7 generates heat when the rotating shaft 61 is rotating. As a result, the inner circumferential surface 8S abuts against the outer circumferential surface 7S so that the fitting between the bearing 7 and the bearing support member 8 is maintained as desired. At this time, the elastic body 9 is pressed radially outward by the outer circumferential surface 7S. Furthermore, when the rotating shaft 61 is not rotating, the bearing 7 is cooled (heat generation subsides). As a result, a gap is generated between the bearing 7 and the bearing support member 8. The gap between the bearing 7 and the bearing support member 8 is designed to be slightly smaller than the gap in the first embodiment. At this time, a portion of the elastic body 9 slightly protrudes radially inward from the inner circumferential surface 8S due to the restoring force (elastic force) of the elastic body 9. That is, for example, at the second temperature (room temperature), when the rotating shaft 61 is not rotating, the elastic body 9 protrudes radially inward from the inner circumferential surface 8S and supports the bearing 7. With this configuration, the pump 1 is capable of pumping the pumped liquid at the first temperature (extremely low temperature). At the second temperature (normal temperature), the pump 1 can be test-run.

[0082] Furthermore, in the present invention, the elastic body 9 is not limited to a metal coil spring as long as a portion of it protrudes inward from the inner peripheral surface 8S at room temperature. That is, for example, the elastic body 9 may be made of a cylindrical elastic material (e.g., rubber). In this case, the shape of the elastic body 9 is not limited to a cylindrical or columnar shape.

[0083] Furthermore, in the present invention, the elastic body 9 does not have to be arranged in the recessed portion R so that the free length direction of the elastic body 9 is along the axial direction. That is, for example, the elastic body 9 may be arranged in the recessed portion R so that the direction perpendicular to the free length direction of the elastic body 9 is along the axial direction. In this case, the shape of the recessed portion R may be, for example, a cylindrical shape along the radial direction.

[0084] Furthermore, in the present invention, the recesses Ra to Rh do not have to be arranged at equal intervals on the inner circumferential surface 8S. That is, for example, it is sufficient that the recesses Ra to Rh are arranged on the inner circumferential surface 8S so that the bearing 7 is fixed (maintained) in a predetermined position (a position where the rotating shaft 61 can be supported).

[0085] Furthermore, in the present invention, a part of the inner circumferential surface 8S at the second temperature (room temperature) may be in contact with a part of the outer circumferential surface 7S.

[0086] ●Embodiments of the present invention● Next, embodiments of the present invention that can be understood from the above-described embodiments will be described below, using the terms and symbols described in the embodiments.

[0087] A first embodiment of the present invention is a centrifugal pump (for example, this pump 1) used at a first temperature (for example, extremely low temperature or high temperature), and includes an impeller (for example, impeller 4) that sucks in a treated liquid and discharges the treated liquid, a rotating shaft (for example, rotating shaft 61) that rotates the impeller, a bearing (for example, bearing 7) that supports the rotating shaft, a bearing support member (for example, bearing support member 8) that is arranged outside the bearing in the radial direction of the rotating shaft and supports the bearing, and three or more elastic bodies (for example, elastic bodies 9a to 9h) that are sandwiched between the bearing and the bearing support member, and the bearing has a cylindrical outer peripheral surface (for example, outer peripheral surface 7S), and the bearing support member has a cylindrical inner peripheral surface (for example, inner peripheral surface 8S) and a periphery of the inner peripheral surface. and three or more recesses (e.g., recesses Ra to Rh) arranged on the inner circumferential surface in a radial direction, the bearing and the bearing support member are each made of metal, the inner circumferential surface is arranged to face the outer circumferential surface, and each of the plurality of elastic bodies is arranged in each of the plurality of recesses so as to abut on the outer circumferential surface, and at the first temperature, the inner circumferential surface abuts on the outer circumferential surface so that a predetermined fit is achieved between the bearing and the bearing support member, and each of the elastic bodies is pressed outward in the radial direction by the outer circumferential surface, and at a second temperature (e.g., room temperature) different from the first temperature, each of the elastic bodies protrudes radially inward beyond the inner circumferential surface to support the bearing. With this configuration, the pump can pump the liquid at extremely low or high temperatures, and the centrifugal pump can be test-run at room temperature.

[0088] A second embodiment of the present invention is a centrifugal pump according to the first embodiment, wherein the first temperature is lower than the second temperature, and the thermal expansion coefficient of the bearing support member is greater than the thermal expansion coefficient of the bearing. With this configuration, the pump can pump the liquid at extremely low temperatures, and the centrifugal pump can be test-run at room temperature.

[0089] A third embodiment of the present invention is a centrifugal pump according to the first embodiment, wherein the first temperature is higher than the second temperature, and the thermal expansion coefficient of the bearing support member is lower than the thermal expansion coefficient of the bearing. With this configuration, the pump can pump the liquid at high temperatures, and the centrifugal pump can be test-run at room temperature.

[0090] A fourth embodiment of the present invention is a centrifugal pump according to the second or third embodiment, wherein the shape of the recess is a groove along the axial direction of the rotating shaft, the elastic body is a coil spring, and the elastic body is arranged in the recess so that the free length direction is along the axial direction. According to this configuration, at the second temperature (room temperature), the bearing is appropriately fixed (maintained) in a predetermined position (a position where the rotating shaft can be supported).

[0091] A fifth embodiment of the present invention is a centrifugal pump in which, in the fourth embodiment, the direction in which one end (e.g., front end 61a) of the rotating shaft is directed in the axial direction is a first direction (e.g., forward direction), and the direction opposite to the first direction is a second direction (e.g., rearward direction), and the recess has a first end (e.g., first end R1) arranged on the first direction side of the recess, and a second end (e.g., second end R2) arranged on the second direction side of the recess, and at least one of the first end and the second end is open toward the axial direction. This configuration makes it easier to assemble the pump during maintenance.

[0092] A sixth embodiment of the present invention is a centrifugal pump in the fifth embodiment, wherein, among the radial directions, a direction passing through the center of the recess in the circumferential direction (e.g., center P1) is a specific radial direction (e.g., specific radial direction D1), and in a direction perpendicular to the specific radial direction and the axial direction, the length of the opening end (e.g., opening end R3, R4) of the recess arranged in the specific radial direction is smaller than the outer diameter (e.g., outer diameter 9r) of the elastic body. This configuration makes it easier to assemble the pump during maintenance.

[0093] A seventh embodiment of the present invention is a centrifugal pump according to the second or third embodiment, wherein in the axial direction of the rotating shaft, the direction in which one end (e.g., front end 61a) of the rotating shaft is directed is a first direction (e.g., forward direction), and the direction opposite to the first direction is a second direction (e.g., rearward direction), the impeller is attached to the end of the rotating shaft on the first direction side, the bearing is arranged on the second direction side of the rotating shaft, and comprises a second bearing (e.g., bearing 7a) arranged on the first direction side of the rotating shaft and supporting the rotating shaft, and a second bearing support member (e.g., bearing support member 8a) arranged outward of the second bearing in the radial direction and supporting the second bearing, and the second bearing and the second bearing support member are each made of a metal having the same thermal expansion coefficient. According to this configuration, the impeller disposed on the first direction side of the rotary shaft is less likely to become misaligned.

[0094] An eighth embodiment of the present invention is a centrifugal pump according to the first embodiment, wherein the bearing and the bearing support member are each made of metal having the same thermal expansion coefficient, and at the first temperature, when the rotating shaft is rotating, the temperature of the bearing is higher than the temperature of the bearing support member, and the inner circumferential surface abuts the outer circumferential surface so that the fit between the bearing and the bearing support member is a predetermined fit, and at the second temperature, when the rotating shaft is not rotating, each of the elastic bodies protrudes radially inward beyond the inner circumferential surface to support the bearing. With this configuration, the pump can pump the liquid at extremely low temperatures, and the centrifugal pump can be test-run at room temperature. [Explanation of symbols]

[0095] 1. Centrifugal pump 4 impellers 61 Rotation axis 7. Bearings 7a Bearing 7b Bearing 7r outer diameter 7S outer surface 8 Bearing support member 8a Bearing support member 8b Bearing support member 8S Inner surface 8r inner diameter 9 Elastic Body 9a Elastic body 9b Elastic body 9c Elastic body 9d Elastic body 9e Elastic body 9f Elastic body 9g elastic body 9h elastic body 9r outer diameter D1 Orthogonal direction P1 center R recess Ra recess Rb recess Rc recess Rd recess Recess Rf recess Rg recess Rh recess R1 First end R2 2nd end R3 Open end R4 Open end

Claims

1. 1. A centrifugal pump for use at a first temperature, comprising: an impeller that sucks in a pumped fluid and discharges the pumped fluid; a rotating shaft that rotates the impeller; a bearing for supporting the rotating shaft; a bearing support member that is disposed outward of the bearing in a radial direction of the rotating shaft and supports the bearing; three or more elastic bodies sandwiched between the bearing and the bearing support member; and The bearing is Cylindrical outer surface, With The bearing support member is a cylindrical inner circumferential surface; three or more recesses arranged on the inner circumferential surface in the circumferential direction of the inner circumferential surface; With the bearing and the bearing support member are each made of metal; The inner circumferential surface is disposed so as to face the outer circumferential surface, The plurality of elastic bodies are respectively disposed in the plurality of recesses so as to abut against the outer circumferential surface, At the first temperature, The inner peripheral surface abuts against the outer peripheral surface so that the fitting between the bearing and the bearing support member is a predetermined fitting, Each of the elastic bodies is pressed outward in the radial direction by the outer circumferential surface, At a second temperature different from the first temperature, Each of the elastic bodies protrudes radially inward beyond the inner circumferential surface and supports the bearing. Centrifugal pump.

2. the first temperature is lower than the second temperature, The thermal expansion coefficient of the bearing support member is greater than the thermal expansion coefficient of the bearing.

2. The centrifugal pump of claim 1.

3. the first temperature is higher than the second temperature, The thermal expansion coefficient of the bearing support member is smaller than the thermal expansion coefficient of the bearing.

2. The centrifugal pump of claim 1.

4. the recessed portion has a groove shape extending along the axial direction of the rotation shaft, The elastic body is It is a coil spring, The elastic body is disposed in the recess so that the free length direction of the elastic body is along the axial direction.

4. The centrifugal pump according to claim 2 or 3.

5. In the axial direction, a direction in which one end of the rotation shaft is oriented is a first direction, and a direction opposite to the first direction is a second direction, The recessed portion is a first end portion of the recess portion that is disposed on the first direction side; a second end portion of the recess portion that is disposed on the second direction side; With At least one of the first end and the second end opens in the axial direction.

5. The centrifugal pump according to claim 4.

6. Among the radial directions, a direction passing through a center of the recess in the circumferential direction is a specific radial direction, a length of an open end of the recess arranged in the specific radial direction in a direction perpendicular to the specific radial direction and the axial direction is smaller than an outer diameter of the elastic body; 6. The centrifugal pump according to claim 5.

7. In the axial direction of the rotation shaft, a direction in which one end of the rotation shaft is oriented is a first direction, and a direction opposite to the first direction is a second direction, The impeller is attached to an end of the rotary shaft on the first direction side, The bearing is disposed on the second direction side of the rotation shaft, a second bearing disposed on the first direction side of the rotation shaft and supporting the rotation shaft; a second bearing support member disposed outward of the second bearing in the radial direction and supporting the second bearing; and the second bearing and the second bearing support member are made of metals having the same thermal expansion coefficient; 4. The centrifugal pump according to claim 2 or 3.

8. the bearing and the bearing support member are made of metals having the same thermal expansion coefficient; When the rotating shaft is rotating at the first temperature, the temperature of the bearing is higher than the temperature of the bearing support member, The inner peripheral surface abuts against the outer peripheral surface so that the fitting between the bearing and the bearing support member is a predetermined fitting, At the second temperature, when the rotating shaft is not rotating, Each of the elastic bodies protrudes radially inward beyond the inner circumferential surface and supports the bearing.

2. The centrifugal pump of claim 1.

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