pump

Abstract

The present invention provides a pump that can reduce the amount of liquid handled by shortening the pre-cooling (pre-heating) time. [Solution] The pumps 1 to 1Z according to the present invention comprise an impeller 26, a pump chamber 22, and a motor unit 3. The motor unit comprises a rotating shaft 5, a stator 7, and a motor housing 4. The rotating shaft comprises an axial passage 51 located inside the rotating shaft along the axial direction of the rotating shaft, a valve 52 located in the axial passage for opening and closing the axial passage, and a projection 5a protruding from the motor housing toward the pump chamber. The axial passage comprises at least one inlet 511 located in the projection and at least one outlet 512 located in a second direction from the inlet. The valve is configured to open the axial passage when a liquid used for pre-cooling or pre-heating the motor is introduced into the axial passage through the pump chamber, and to close the axial passage when the impeller rotates and discharges the liquid being handled.

Description

Technical Field

[0001] The present invention relates to a pump.

Background Art

[0002] Pumps for pumping handling liquids at temperatures away from normal temperature (e.g., 20°C ± 15°C) are known (see, for example, Patent Document 1). Each member of the pump (e.g., the housing, the rotating shaft, the bearings, etc.) is, for example, made of metal. During the operation of the pump, each member is in contact with the handling liquid flowing inside the pump. Therefore, for example, when the handling liquid flowing inside a centrifugal pump is an extremely low-temperature liquid (e.g., -230°C) such as liquid hydrogen or a high-temperature liquid (e.g., 150°C) such as oil, each member is cooled or heated by the handling liquid. As a result, each member shrinks or expands.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The material of each component is selected appropriately based on various factors (e.g., pump performance and size, temperature and properties of the fluid being handled, pump operating environment, etc.). Therefore, the materials of each component may be metals with different coefficients of thermal expansion. In this case, the fit between each component (the relative positional relationship between each component) changes depending on the temperature of the fluid being handled. Accordingly, each component is designed so that the pump operates normally at the operating temperature (cryogenic or high temperature). That is, for example, at the operating temperature of the pump, the fit between each component (the relative positional relationship between each component) is appropriate, while at the temperature when the pump is not operating (e.g., room temperature), the fit becomes inappropriate (gaps may occur between each component). Therefore, pre-cooling (pre-heating) of the pump (each component) is necessary before the pump starts operating.

[0005] Typically, the handling fluid is used to pre-cool (pre-heat) a pump. The internal structure of a pump is complex, with many small gaps and thick components. Therefore, a long time and a large amount of handling fluid are required for the fluid to circulate throughout the pump and for each component to be sufficiently pre-cooled (pre-heated).

[0006] The present invention aims to provide a pump that can reduce the amount of liquid handled by shortening the pre-cooling (pre-heating) time. [Means for solving the problem]

[0007] A pump in one embodiment of the present invention comprises an impeller for drawing in and discharging a liquid, a pump chamber for housing the impeller, and a motor unit for rotating the impeller. The motor unit comprises a rotating shaft to which the impeller is attached, a stator for rotating the rotating shaft, and a motor housing for housing the rotating shaft and the stator. The direction in which the impeller is positioned relative to the motor housing is a first direction, and the direction opposite to the first direction is a second direction. The rotating shaft has an axial flow path arranged inside the rotating shaft so as to be aligned with the axial direction of the rotating shaft. The motor comprises a valve positioned in the shaft passage for opening and closing the shaft passage, and a projection extending from the motor housing toward the pump chamber to which the impeller is attached, wherein the shaft passage comprises at least one inlet positioned in the projection and at least one outlet positioned in the second direction from the inlet, and the valve is configured to open the shaft passage when a liquid used for pre-cooling or pre-heating the motor section is introduced into the shaft passage via the pump chamber, and to close the shaft passage when the impeller rotates and discharges the liquid being handled. [Effects of the Invention]

[0008] This invention can reduce the amount of liquid handled by shortening the pre-cooling (pre-heating) time. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view of an embodiment of the pump according to the present invention. [Figure 2] This is a partially enlarged schematic cross-sectional view of the pump, showing the vicinity of the valve. [Figure 3] This is a schematic cross-sectional view of the pump shown above, illustrating the state in which pre-cooling is being performed. [Figure 4] This is a partially enlarged schematic cross-sectional view of the pump showing the state of the valve when pre-cooling is being performed. [Figure 5] This is a schematic cross-sectional view of the pump in operation. [Figure 6]This is a partially enlarged schematic cross-sectional view of the pump, showing the state of the valve in the pump while it is in operation. [Figure 7] This is a schematic cross-sectional view of the pump, showing another embodiment of the pump according to the present invention. [Figure 8] Figure 7 is a partially enlarged schematic cross-sectional view of the pump, showing the vicinity of the auxiliary valve. [Figure 9] Figure 7 is a schematic cross-sectional view of the pump showing the pump in a state where pre-cooling is being performed. [Figure 10] Figure 7 is a partially enlarged schematic cross-sectional view of the pump, showing the state of the auxiliary valve when pre-cooling of the pump is being performed. [Figure 11] This is a schematic cross-sectional view of the pump in operation shown in Figure 7. [Figure 12] This is a partially enlarged schematic cross-sectional view of the pump, showing the state of the auxiliary valve of the pump in operation (Figure 7). [Figure 13] This is a schematic cross-sectional view of the pump, showing yet another embodiment of the pump according to the present invention. [Figure 14] Figure 13 is a schematic cross-sectional view of the pump showing the pump in a state where pre-cooling is being performed. [Figure 15] This is a schematic cross-sectional view of the pump, showing yet another embodiment of the pump according to the present invention. [Figure 16] Figure 15 is a partially enlarged schematic cross-sectional view of the pump, showing the vicinity of the valve. [Figure 17] Figure 16 is a partially enlarged schematic cross-sectional view of the pump, showing the pump in a state where pre-cooling is being performed. [Figure 18] This is a schematic cross-sectional view of the pump in a modified example. [Figure 19] Figure 15 is a partially enlarged schematic cross-sectional view of the vicinity of the valve, showing another embodiment of the valve in the pump. [Modes for carrying out the invention]

[0010] Embodiments of the pump according to the present invention (hereinafter referred to as "the present pump") will be described below. In the following description, each drawing is referred to as appropriate. In each drawing, the same members and elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, the dimensional ratios of each element may be exaggerated for convenience of explanation and are not limited to the ratios shown in each drawing.

[0011] ● Pump (1) ● ● Configuration of the pump First, the configuration of the present pump will be described.

[0012] FIG. 1 is a schematic cross-sectional view of the present pump showing an embodiment of the present pump.

[0013] The present pump 1 pumps the handling liquid. The present pump 1 includes a pump section 2 and a motor section 3.

[0014] The "handling liquid" is the liquid to be pumped by the present pump 1, and in particular, it is a liquid at a temperature (hereinafter referred to as "specific temperature") that requires pre-cooling or pre-heating of the present pump 1 before the operation of the present pump 1. In the present embodiment, the handling liquid is an extremely low temperature liquid (for example, liquid hydrogen), and the specific temperature is an extremely low temperature (for example, -253°C).

[0015] In the following description, the "front direction" is the direction in which the impeller 26 (described later) is arranged with respect to the motor section 3, and the "rear direction" is the opposite direction of the front direction. The front direction is an example of the first direction in the present invention, and the rear direction is an example of the second direction in the present invention.

[0016] The pump section 2 sucks and discharges the handling liquid. The pump section 2 includes a housing 21, a pump chamber 22, a suction port 23, a discharge port 24, an internal flow path 25, and an impeller 26.

[0017] The housing 21 houses the impeller 26 and the motor unit 3, and partitions the pump chamber 22 and the internal flow path 25. The housing 21 is made of, for example, an aluminum alloy. The front end of the housing 21 extends cylindrically forward, forming the suction port 23. The rear end of the housing 21 extends cylindrically backward, forming the discharge port 24. Between the housing 21 and the motor unit 3 (housing 31 (described later)), the internal flow path 25 is partitioned so as to surround the motor unit 3. The internal flow path 25 communicates with the pump chamber 22 and the discharge port 24. In other words, the housing 21 constitutes the pump chamber 22, the suction port 23, the discharge port 24, and the internal flow path 25.

[0018] The pump room 22 houses the impeller 26.

[0019] The suction port 23 is the flow path for the liquid being drawn into the pump chamber 22.

[0020] The discharge port 24 is the flow path for the liquid being handled, which is discharged from the pump chamber 22.

[0021] The internal flow path 25 is a flow path that guides the liquid being handled, which is drawn into the pump chamber 22 from the suction port 23, to the discharge port 24.

[0022] The impeller 26 is attached to the motor unit 3 and rotates as the motor unit 3 operates. As the impeller 26 rotates, the liquid being handled, which is drawn into the pump chamber 22 from the suction port 23, is discharged to the outside of the pump 1 via the impeller 26, the internal flow path 25, and the discharge port 24.

[0023] The motor unit 3 is driven under predetermined driving conditions to rotate the impeller 26. The motor unit 3 is housed in the housing 21. The motor unit 3 comprises a housing 4, a rotating shaft 5, a rotor 6, a stator 7, and bearings 8 and 9.

[0024] The housing 4 accommodates the rotating shaft 5, rotor 6, stator 7, and bearings 8 and 9. The shape of the housing 4 is substantially cylindrical, oriented in the front-rear direction. The housing 4 is made of, for example, an aluminum alloy. The housing 4 comprises a motor chamber 41, a front bracket portion 42, a rear bracket portion 43, and a peripheral wall portion 44. The housing 4 is an example of a motor housing in the present invention.

[0025] The motor chamber 41 houses the rotating shaft 5, rotor 6, stator 7, and bearings 8 and 9. The motor chamber 41 is an internal space of the housing 4, partitioned by the housing 4. The motor chamber 41 includes a front space 42S and a rear space 43S (both described later). The motor chamber 41 is an example of an internal space in the present invention.

[0026] The front bracket portion 42 holds the bearing 8. The shape of the front bracket portion 42 is cylindrical. The front bracket portion 42 is located at the front end of the housing 4. The front bracket portion 42 partitions the pump chamber 22. The space inside the front bracket portion 42 (hereinafter referred to as "front space 42S") is in communication with the pump chamber 22.

[0027] The rear bracket portion 43 holds the bearing 9. The rear bracket portion 43 is cylindrical in shape. The rear bracket portion 43 is located at the rear end of the housing 4. The rear bracket portion 43 partitions a part of the internal flow path 25. The space inside the rear bracket portion 43 (hereinafter referred to as "rear space 43S") is in communication with the internal flow path 25.

[0028] The peripheral wall portion 44 has a cylindrical shape. A front bracket portion 42 is arranged adjacent to the peripheral wall portion 44 in a cylindrical shape in the front direction, and a rear bracket portion 43 is arranged adjacent to the peripheral wall portion 44 in the rear direction. The peripheral wall portion 44 partitions a part of the internal flow path 25.

[0029] The rotating shaft 5 rotates due to the rotation of the rotor 6 and transmits rotational power to the impeller 26. In other words, the rotating shaft 5 rotates the impeller 26. The shape of the rotating shaft 5 is cylindrical along the front-rear direction. The rotating shaft 5 is made of, for example, stainless steel. The rotating shaft 5 is inserted into the rotor 6 and fixed to the rotor 6. The rotating shaft 5 comprises a front end 5a, a front end face 5b, a rear end face 5c, an outer circumferential surface 5d, an axial flow path 51, and a valve 52.

[0030] In the following explanation, "axial direction" refers to the direction along the axis of rotation of the rotation axis 5 (front-back direction). "Radial direction" refers to the radial direction of the rotation axis 5. "Inward direction" refers to the inward direction in the radial direction, and "outward direction" refers to the outward direction in the radial direction. "Circumferential direction" refers to the circumferential direction of the rotation axis 5.

[0031] The front end portion 5a protrudes forward from the housing 4 toward the pump chamber 22 and is located inside the pump chamber 22. An impeller 26 is attached to the front end portion 5a. The front end portion 5a is an example of a protruding portion in the present invention.

[0032] In this invention, the front end portion 5a may protrude into the interior of the suction port 23. In this case, the pump chamber 22 and the suction port 23 are examples of the pump chamber in this invention.

[0033] The front end surface 5b is a surface oriented in the forward direction. The front end surface 5b is located at the front end 5a. That is, the front end surface 5b is located in the pump chamber 22 and faces the pump chamber 22.

[0034] The rear end surface 5c is a surface oriented towards the rear. The rear end surface 5c is housed in the rear bracket portion 43. That is, the rear end surface 5c is located in the rear space 43S (in other words, the motor room 41). As a result, the rear end surface 5c faces the region of the internal flow path 25 that is located towards the rear of the rotating shaft 5. The rotating shaft 5 is housed in the housing 4, except for the front end portion 5a.

[0035] The outer surface 5d is a surface that faces outward. The shape of the outer surface 5d is cylindrical.

[0036] Figure 2 is a partially enlarged schematic cross-sectional view of the pump 1 showing the vicinity of the valve 52 on the rotating shaft 5. In the following description, Figure 1 will be referred to together with Figure 2 as appropriate.

[0037] The axial passage 51 is a passage for the pre-cooling liquid (described later; the same applies hereafter) and is a through-hole that penetrates the rotating shaft 5 in the front-rear direction. The axial passage 51 is located inside the rotating shaft 5 from the front end surface 5b to the rear end surface 5c so as to be aligned with the front-rear direction. The shape of the axial passage 51 is, for example, cylindrical. The axial passage 51 comprises an inlet 511, an outlet 512, a valve chamber 513, and a seating surface 514.

[0038] The inlet 511 introduces the pre-cooling liquid into the axial flow path 51. The inlet 511 is located on the front end surface 5b. That is, the inlet 511 opens toward the pump chamber 22.

[0039] The outlet 512 leads the pre-cooled liquid out of the axial flow path 51. The outlet 512 is located on the rear end face 5c. That is, the outlet 512 is located further back than the inlet 511 and opens toward the internal flow path 25. As a result, the axial flow path 51 communicates with the internal flow path 25 via the outlet 512 and the rear space 43S. The outlet 512 is an example of an end face outlet in the present invention.

[0040] The valve chamber 513 houses the valve 52. The valve chamber 513 is located in a part of the axial flow path 51 (in this embodiment, at the rear end). The front-facing surface of the valve chamber 513 functions as a seating surface 514.

[0041] Valve 52 opens and closes the axial passage 51. Valve 52 is housed in a valve chamber 513. That is, valve 52 is positioned in the axial passage 51. Valve 52 comprises a valve body 521 and a biasing member 522.

[0042] The valve body 521 opens and closes the axial passage 51 by moving inside the valve chamber 513. The shape of the valve body 521 is, for example, spherical. The valve body 521 is made of, for example, stainless steel.

[0043] The biasing member 522 biases the valve body 521 forward (towards the seating surface 514). The biasing member 522 is, for example, a coil spring made of stainless steel. The biasing member 522 is positioned behind the valve body 521. The spring constant of the biasing member 522 is set to such an extent that the valve body 521 can move backward due to the hydraulic pressure of the pre-cooling liquid.

[0044] The rotor 6 rotates due to the rotating magnetic field generated by the stator 7. The rotor 6 has a cylindrical shape that is aligned along the axial direction.

[0045] The stator 7 generates a rotating magnetic field that rotates the rotor 6 (rotating shaft 5). The shape of the stator 7 is cylindrical along the axial direction.

[0046] Bearings 8 and 9 rotatably support the rotating shaft 5. Bearings 8 and 9 are, for example, known ball bearings. Bearings 8 and 9 are, for example, made of stainless steel. Bearing 8 is mounted on the front bracket portion 42 and supports the front part of the rotating shaft 5. Bearing 9 is mounted on the rear bracket portion 43 and supports the rear part of the rotating shaft 5.

[0047] In this configuration, the fit between each component (e.g., housing 4, rotating shaft 5, bearings 8, 9, etc.) is designed to be appropriate (allowing the pump 1 to pump fluid normally) at a specific temperature. Therefore, at temperatures far from the specific temperature (e.g., room temperature), the fit becomes inappropriate (allowing the pump 1 to pump fluid normally). Consequently, the pump 1 requires pre-cooling before operation begins.

[0048] "Pre-cooling" refers to the process of cooling the temperature of each component of the pump 1 to a predetermined temperature (the temperature of the fluid being handled) before the pump 1 is put into operation. "Pre-cooling liquid" is the liquid used for pre-cooling and is the fluid being handled.

[0049] ● Operation of pump (1) Next, the operation of pump 1 will be explained below, focusing on the operation of valve 52. Figures 1 and 2 will be referred to as appropriate in the following explanation.

[0050] As mentioned above, when pump 1 is not operating, pre-cooling of pump 1 is performed before pump 1 starts operating.

[0051] Figure 3 is a schematic cross-sectional view of the pump 1 showing the state in which pre-cooling is being performed. Figure 4 is a partially enlarged schematic cross-sectional view of the pump 1 showing the state of valve 52 when pre-cooling is being performed. In these figures, a portion of the pre-cooling liquid flow is indicated by thick arrows.

[0052] The pre-cooling liquid is pressurized by a predetermined pressurizing means (e.g., a pump, gas pressurizer, etc.) and introduced into the pump 1. The pre-cooling liquid mainly flows in the following order: suction port 23, pump chamber 22, impeller 26, internal passage 25 (i.e., between housings 21 and 4), and discharge port 24 (first flow F1). At this time, each component in contact with the pre-cooling liquid (pump chamber 22, suction port 23, discharge port 24, internal passage 25, impeller 26, housing 4, etc.) is cooled by the pre-cooling liquid. The pre-cooling liquid also flows through bearings 8 and 9 to the motor chamber 41 (second flow F2). At this time, each component in contact with the pre-cooling liquid (rotating shaft 5, rotor 6, stator 7, bearings 8 and 9, etc.) and the motor chamber 41 are cooled by the pre-cooling liquid. Furthermore, the pre-cooling liquid introduced into the pump chamber 22 flows from the inlet 511 into the shaft passage 51. The pre-cooling liquid flowing through the axial passage 51 moves the valve body 521 backward due to its hydraulic pressure. At this time, the axial passage 51 (valve 52) opens. Consequently, the pre-cooling liquid flowing through the axial passage 51 flows into the internal passage 25 via the valve chamber 513, outlet 512, and rear space 43S (third flow F3). At this time, the rotating shaft 5 in contact with the pre-cooling liquid is cooled from the inside by the pre-cooling liquid.

[0053] Here, the second flow F2 is the flow that passes through bearings 8 and 9. Therefore, the flow rate of the second flow F2 is considerably less than that of the first flow F1. Consequently, the cooling rate inside the motor section 3 may be slow with only the second flow F2. Therefore, in this pump 1, the rotating shaft 5 is cooled from the inside by the third flow F3. As a result, the rotating shaft 5 and rotor 6 are rapidly cooled by the third flow F3.

[0054] After pre-cooling is complete, pump 1 becomes operational (for pumping the liquid being handled).

[0055] Figure 5 is a schematic cross-sectional view of the pump 1 in operation. Figure 6 is a partially enlarged schematic cross-sectional view of the pump 1 showing the state of valve 52 in operation. In these figures, a portion of the flow of the fluid being handled is indicated by thick arrows.

[0056] During the operation of the pump 1, the handling fluid is introduced into the pump chamber 22 via the suction port 23. The handling fluid introduced into the pump chamber 22 is drawn into the impeller 26, discharged into the internal passage 25, and then discharged to the outside of the pump 1 through the discharge port 24. The handling fluid flowing through the internal passage 25 is also introduced into the motor chamber 41 via the bearing 9, filling the motor chamber 41, and is returned to the pump chamber 22 via the bearing 8. At this time, the handling fluid flowing through the internal passage 25 also enters the valve chamber 513 from the outlet 512. In addition, the handling fluid introduced into the pump chamber 22 also enters the shaft passage 51 from the inlet 511. Therefore, the front of the valve body 521 is filled with the handling fluid that has entered from the pump chamber 22, and the rear of the valve body 521 is filled with the handling fluid that has entered from the internal passage 25. The handling fluid flowing through the internal passage 25 is pressurized by the impeller 26. Therefore, the hydraulic pressure of the fluid being handled in the rear direction of the valve body 521 is higher than the hydraulic pressure of the fluid being handled in the front direction of the valve body 521. Consequently, the valve body 521 is pressed against the seat surface 514 by the hydraulic pressure of the fluid being handled and the biasing force of the biasing member 522, and the axial passage 51 (valve 52) closes. As a result, backflow of the fluid being handled through the axial passage 51 is prevented.

[0057] Thus, the motor unit 3 is cooled from the outside by the first flow F1 and from the inside by the second and third flows F2 and F3. As a result, in this pump 1, the motor unit 3 is cooled in a shorter time compared to the motor unit in a conventional pump that does not have an axial flow path 51 (hereinafter referred to as "conventional pump"). Therefore, the amount of pre-cooling liquid is also reduced. In other words, the time required for pre-cooling (pre-cooling time) is shortened, and the amount of pre-cooling liquid is reduced.

[0058] Furthermore, valve 52 functions as a one-way valve, allowing the pre-cooling liquid to pass from the front to the rear and preventing the handling liquid from passing from the rear to the front. Therefore, backflow of the handling liquid through the axial passage 51 is prevented. As a result, no performance degradation of the pump 1 due to such backflow occurs.

[0059] ●Summary (1) In the above description, the rotating shaft 5 comprises a front end 5a, an axial passage 51, and a valve 52. The front end 5a protrudes from the housing 4 toward the pump chamber 22, and an impeller 26 is attached to the front end 5a. The axial passage 51 is located inside the rotating shaft 5 so as to be aligned with the axial direction. The valve 52 is located in the axial passage 51 and opens and closes the axial passage 51. The axial passage 51 comprises an inlet 511 and an outlet 512. The inlet 511 is located in the front end 5a, and the outlet 512 is located on the rear end face 5c, further back than the inlet 511. The valve 52 is configured to open the axial passage 51 when pre-cooled liquid is introduced into the axial passage 51 via the pump chamber 22, and to close the axial passage 51 when the impeller 26 rotates and discharges the liquid being handled (during the operation of the pump 1). In this configuration, the motor unit 3 is cooled from the inside by the third flow F3. Therefore, compared to conventional pumps, this pump 1 shortens the pre-cooling time and reduces the amount of pre-cooled liquid. In addition, backflow of the handled liquid through the axial flow path 51 is prevented during the operation of this pump 1. As a result, there is no performance degradation of this pump 1 due to such backflow.

[0060] In the above description, the pump 1 is equipped with a discharge port 24 and an internal flow path 25. The internal flow path 25 guides the liquid being handled, discharged from the impeller 26, to the discharge port 24. The outlet 512 is located on the rear end face 5c and opens toward the internal flow path 25. In this configuration, the pre-cooling liquid cools the rotating shaft 5 from the inside up to the rear end of the rotating shaft 5. Therefore, the pre-cooling time is further shortened and the amount of pre-cooling liquid required is further reduced.

[0061] In the above description, valve 52 is designed to open the axial passage 51 by the hydraulic pressure of the pre-cooling liquid when the pre-cooling liquid is introduced into the axial passage 51 via the pump chamber 22. Valve 52 is also designed to close the axial passage 51 by the hydraulic pressure of the handled liquid when the impeller 26 rotates and discharges the handled liquid (during the operation of the main pump 1). With this configuration, valve 52 can reliably ensure the flow of the pre-cooling liquid during pre-cooling and reliably prevent backflow of the handled liquid during the operation of the main pump 1.

[0062] In the above description, the inlet 511 is positioned forward of the impeller 26. In this configuration, the pre-cooling liquid is easily introduced into the shaft flow path 51 without being obstructed by the impeller 26. Furthermore, the pre-cooling liquid cools the rotating shaft 5 from the front end 5a. As a result, the pre-cooling time is further shortened and the amount of pre-cooling liquid required is further reduced.

[0063] ●Pump (2)● Next, another embodiment of this pump (hereinafter referred to as the "second embodiment") will be described below, focusing on the differences from the previously described embodiment (hereinafter referred to as the "first embodiment"). In the second embodiment, the configuration of the motor section differs from that of the first embodiment. In the following description of the second embodiment, for the sake of clarity, the same reference numerals as in the first embodiment and components having common functions are used, and detailed explanations are omitted. Figures 1 and 2 will be referenced as appropriate in the following description.

[0064] ●Pump (2) configuration Figure 7 is a schematic cross-sectional view of the pump, showing a second embodiment of the pump.

[0065] This pump 1X delivers the liquid being handled. This pump 1X comprises a pump unit 2 and a motor unit 3X.

[0066] The motor unit 3X is driven under predetermined driving conditions to rotate the impeller 26. The motor unit 3X is housed in the housing 21. The motor unit 3X comprises the housing 4X, a rotating shaft 5, a rotor 6, a stator 7, and bearings 8 and 9.

[0067] The housing 4X houses the rotating shaft 5, rotor 6, stator 7, and bearings 8, 9. The shape of the housing 4X is substantially cylindrical along the front-rear direction. The housing 4X is made of, for example, an aluminum alloy. The housing 4X comprises a motor chamber 41, a front bracket portion 42, a rear bracket portion 43, a peripheral wall portion 44, two auxiliary passages 45, and two auxiliary valves 46. The housing 4X is an example of a motor housing in the present invention.

[0068] Figure 8 is a partially enlarged schematic cross-sectional view of the pump 1X showing the vicinity of the auxiliary valve 46 of the housing 4X. In the following description, Figure 7 will be referred to together with Figure 8 as appropriate.

[0069] The auxiliary passage 45 is a passage for pre-cooling liquid and is a through-hole that penetrates the front bracket portion 42 (housing 4) in the front-rear direction. The auxiliary passage 45 is located inside the front bracket portion 42 (housing 4) so ​​as to be aligned with the front-rear direction. The shape of the auxiliary passage 45 is, for example, cylindrical. The auxiliary passage 45 is located on the outside of the bearing 8. That is, in an axial view, the auxiliary passage 45 is located near the bearing 8 so as to sandwich the bearing 8 together with the axial passage 51. The auxiliary passage 45 comprises an inlet 451, an outlet 452, a valve chamber 453, and a seating surface 454.

[0070] The inlet 451 introduces the pre-cooling liquid into the auxiliary flow path 45. The inlet 451 is located on the front surface of the front bracket section 42 and opens toward the pump chamber 22.

[0071] The outlet 452 leads the pre-cooling liquid from the auxiliary flow path 45. The outlet 452 is located on the rear surface of the front bracket portion 42 and opens toward the motor chamber 41.

[0072] The valve chamber 453 houses the auxiliary valve 46. The valve chamber 453 is located in a part of the auxiliary flow path 45 (the rear end in the second embodiment). The front-facing surface of the valve chamber 453 functions as a seating surface 454.

[0073] The auxiliary valve 46 opens and closes the auxiliary passage 45. The auxiliary valve 46 is housed in the valve chamber 453. That is, the auxiliary valve 46 is positioned in the auxiliary passage 45. The auxiliary valve 46 comprises an auxiliary valve body 461 and a biasing member 462.

[0074] The auxiliary valve body 461 opens and closes the auxiliary passage 45 by moving inside the valve chamber 453. The shape of the auxiliary valve body 461 is, for example, spherical. The auxiliary valve body 461 is made of, for example, an aluminum alloy.

[0075] The biasing member 462 biases the auxiliary valve body 461 forward (towards the seating surface 454). The biasing member 462 is, for example, a coil spring made of aluminum alloy. The biasing member 462 is positioned behind the auxiliary valve body 461. The spring constant of the biasing member 462 is set to such an extent that the auxiliary valve body 461 can move backward due to the hydraulic pressure of the pre-cooling liquid.

[0076] ● Operation of pump (2) Next, the operation of pump 1X will be described below, focusing on the operation of the auxiliary valve 46. Figures 7 and 8 will be referred to as appropriate in the following description.

[0077] Figure 9 is a schematic cross-sectional view of the pump 1X showing the state in which pre-cooling is being performed. Figure 10 is a partially enlarged schematic cross-sectional view of the pump 1X showing the state of the auxiliary valve 46 when pre-cooling is being performed. In these figures, a portion of the pre-cooling liquid flow is indicated by thick arrows.

[0078] When pre-cooling is performed, the first to third flows F1 to F3 occur, similar to the first embodiment.

[0079] The pre-cooling liquid introduced into the pump chamber 22 (a portion of the pre-cooling liquid directed toward the second flow F2) flows around the impeller 26 and also flows from the inlet 451 into the auxiliary flow path 45. The pre-cooling liquid flowing into the auxiliary flow path 45 moves the auxiliary valve body 461 backward due to its hydraulic pressure. At this time, the auxiliary flow path 45 (auxiliary valve 46) opens. Therefore, the pre-cooling liquid flowing into the auxiliary flow path 45 flows into the motor chamber 41 via the valve chamber 453 and outlet 452 (fourth flow F4). At this time, the rotor 6 and stator 7 (motor chamber 41) are cooled by the pre-cooling liquid. In addition, the bearing 8 is cooled from the inside by the second flow F2 and also from the outside by the pre-cooling liquid of the fourth flow F4.

[0080] Thus, in this pump 1X, the path for the pre-cooling liquid flowing to the motor chamber 41 is greater than in this pump 1 of the first embodiment. Therefore, the rotor 6, stator 7, bearings 8 and 9, and motor chamber 41 are cooled by the pre-cooling liquid in a shorter time than in the first embodiment. As a result, the amount of pre-cooling liquid is reduced compared to the first embodiment.

[0081] Figure 11 is a schematic cross-sectional view of the pump 1X in operation. Figure 12 is a partially enlarged schematic cross-sectional view of the pump 1X showing the state of the auxiliary valve 46 of the pump 1X in operation. In these figures, a portion of the flow of the fluid being handled is indicated by thick arrows.

[0082] Similar to the first embodiment, during the operation of the pump 1X, the handling fluid flowing through the internal passage 25 is introduced into the motor chamber 41 via the bearing 9, filling the motor chamber 41. At this time, the handling fluid introduced into the motor chamber 41 also enters the valve chamber 453 from the outlet 452. In addition, the handling fluid introduced into the pump chamber 22 also enters the auxiliary passage 45 from the inlet 451. Therefore, the area in front of the auxiliary valve body 461 is filled with handling fluid that has entered from the pump chamber 22, and the area behind the auxiliary valve body 461 is filled with handling fluid that has entered from the motor chamber 41. The handling fluid introduced into the motor chamber 41 is pressurized by the impeller 26. Therefore, the hydraulic pressure of the handling fluid behind the auxiliary valve body 461 is higher than the hydraulic pressure of the handling fluid in front of the auxiliary valve body 461. Therefore, the auxiliary valve body 461 is pressed against the seat surface 454 by the hydraulic pressure of the fluid being handled and the biasing force of the biasing member 462, and the auxiliary passage 45 (auxiliary valve 46) closes. As a result, backflow of the fluid being handled through the auxiliary passage 45 is prevented.

[0083] Thus, the motor unit 3X is cooled from the outside by the first flow F1 and from the inside by the second to fourth flows F2 to F4. As a result, in this pump 1X, the motor unit 3X is cooled in an even shorter time compared to the motor unit in a conventional pump. Therefore, the amount of pre-cooling liquid is also reduced. In other words, the pre-cooling time is further shortened and the amount of pre-cooling liquid is further reduced.

[0084] Furthermore, the auxiliary valve 46 functions as a one-way valve, allowing the pre-cooling liquid to pass from front to back and preventing the handling liquid from passing from back to front. Therefore, backflow of the handling liquid through the auxiliary passage 45 is prevented. As a result, no performance degradation of the pump 1X due to such backflow occurs.

[0085] ●Summary (2) In the above description, the pump 1X, specifically the motor unit 3X, is equipped with an auxiliary passage 45 and an auxiliary valve 46. The auxiliary passage 45 penetrates the housing 4. The auxiliary valve 46 is located in the auxiliary passage 45 and opens and closes it. The handling fluid discharged from the impeller 26 is introduced into the motor chamber 41. When the pre-cooling fluid is introduced into the auxiliary passage 45, the auxiliary valve 46 opens the auxiliary passage 45 due to the hydraulic pressure of the pre-cooling fluid, and when the impeller 26 rotates and discharges the handling fluid, the auxiliary passage 45 closes due to the hydraulic pressure of the handling fluid discharged from the impeller 26. In this configuration, the pre-cooling time is further shortened and the amount of pre-cooling fluid is further reduced compared to the motor unit 3 in the first embodiment.

[0086] In the above description, the auxiliary flow path 45 is positioned outward from the bearing 8. In this configuration, the bearing 8 is cooled from the inside by the second flow F2 and from the outside by the fourth flow F4.

[0087] ●Pump (3)● Next, yet another embodiment of the pump according to the present invention (hereinafter referred to as the "third embodiment") will be described below, focusing on the differences from the first and second embodiments. In the third embodiment, the configuration of the rotating shaft differs from that of the first and second embodiments. In the following description of the third embodiment, for the sake of convenience, the same reference numerals as in the first and second embodiments, and components having common functions, are used, and detailed descriptions are omitted. In the following description, Figures 1, 2, 7, and 8 will be referenced as appropriate.

[0088] ● Pump (3) configuration Figure 13 is a schematic cross-sectional view of the pump, showing a third embodiment of the pump.

[0089] This pump 1Y is used to pump the liquid being handled. This pump 1Y comprises a pump unit 2 and a motor unit 3Y.

[0090] The motor unit 3Y is driven under predetermined driving conditions to rotate the impeller 26. The motor unit 3Y is housed in the housing 21. The motor unit 3Y comprises a housing 4X, a rotating shaft 5Y, a rotor 6, a stator 7, and bearings 8 and 9.

[0091] The rotating shaft 5Y rotates due to the rotation of the rotor 6 and transmits rotational power to the impeller 26. In other words, the rotating shaft 5Y rotates the impeller 26. The shape of the rotating shaft 5Y is cylindrical along the front-rear direction. The rotating shaft 5Y is made of stainless steel, for example. The rotating shaft 5Y is inserted into the rotor 6 and fixed to the rotor 6. The rotating shaft 5Y includes a front end 5a, a front end face 5b, a rear end face 5c, an outer circumferential surface 5d, an axial flow path 51Y, and a valve 52.

[0092] The axial passage 51Y is a passage for the pre-cooling liquid and is a through-hole that penetrates the rotating shaft 5Y in the front-rear direction. The axial passage 51Y is located inside the rotating shaft 5Y from the front end surface 5b to the rear end surface 5c, along the front-rear direction. The axial passage 51Y comprises an inlet 511, an outlet 512, a valve chamber 513, a seating surface 514 (see Figure 2), and two intermediate outlets 515.

[0093] The valve chamber 513 is located in a part of the axial flow path 51Y (in the third embodiment, the front end 5a).

[0094] The intermediate outlet 515 leads the pre-cooling liquid from the axial flow path 51Y. In the circumferential direction, the intermediate outlets 515 are arranged at equal intervals (180° intervals) on the outer circumferential surface 5d. In the axial direction, the intermediate outlets 515 are located between the rotor 6 and the bearing 9. That is, the intermediate outlets 515 are located behind the inlet 511 and open toward the motor chamber 41. The intermediate outlet 515 is an example of a circumferential outlet in the present invention.

[0095] ● Operation of pump (3) Next, the operation of this pump 1Y will be described below, focusing on the differences between its operation and that of the first and second embodiments. Figure 13 will be referenced as appropriate in the following description.

[0096] Figure 14 is a schematic cross-sectional view of pump 1Y showing the pump 1Y in the state where pre-cooling is being performed. In this figure, a portion of the pre-cooling liquid flow is indicated by a thick arrow.

[0097] When pre-cooling is performed, the first to fourth flows F1 to F4 are generated, similar to the second embodiment.

[0098] The pre-cooling liquid that flows from the pump chamber 22 into the axial flow path 51Y also flows into the motor chamber 41 from the intermediate outlet 515 (fifth flow F5). At this time, the rotor 6 and stator 7 (motor chamber 41) are cooled by the pre-cooling liquid.

[0099] Thus, the axial flow path 51Y has two types (three) of outlets: the outlet 512 and two intermediate outlets 515. In other words, the outlets of the axial flow path 51Y include the outlet 512 and two intermediate outlets 515. Therefore, in this pump 1Y, the path for the pre-cooling liquid flowing to the motor chamber 41 is greater than that of this pump 1X in the second embodiment. As a result, in this pump 1Y, the motor section 3Y is cooled in an even shorter time compared to the motor section 3X in the second embodiment. Therefore, the amount of pre-cooling liquid is reduced compared to the second embodiment.

[0100] During the operation of pump 1Y, the fluid being handled is introduced into the motor chamber 41 not only from the bearing 9 but also from the intermediate outlet 515. Here, the fluid being handled introduced into the motor chamber 41 from both the bearing 9 and the intermediate outlet 515 is introduced from the internal passage 25. In other words, even if the intermediate outlet 515 were not present, the fluid being handled would still be introduced into the motor chamber 41 from the internal passage 25. Therefore, even if the fluid being handled is introduced into the motor chamber 41 from the intermediate outlet 515 during the operation of pump 1Y, this introduction does not affect the performance of pump 1Y.

[0101] ●Summary (3) In the above description, the axial flow path 51Y is equipped with an intermediate outlet 515. The intermediate outlet 515 is located on the outer circumferential surface 5d and opens toward the motor chamber 41. In this configuration, the motor section 3Y is cooled in an even shorter time compared to the motor section 3X in the second embodiment. Therefore, the amount of pre-cooling liquid is further reduced.

[0102] ●Pump (4)● Next, yet another embodiment of the pump according to the present invention (hereinafter referred to as the "fourth embodiment") will be described below, focusing on the differences from the first to third embodiments. In the fourth embodiment, the configuration of the rotating shaft differs from that of the first to third embodiments. In the following description of the fourth embodiment, for the sake of clarity, the same reference numerals as in the first to third embodiments and components having common functions are used, and detailed explanations are omitted.

[0103] ● Pump (4) configuration Figure 15 is a schematic cross-sectional view of the pump, showing a fourth embodiment of the pump.

[0104] Pump 1Z is used to pump the liquid being handled. Pump 1Z comprises a pump unit 2 and a motor unit 3Z.

[0105] The motor unit 3Z is driven under predetermined driving conditions to rotate the impeller 26. The motor unit 3Z is housed in the housing 21. The motor unit 3Z comprises the housing 4, the rotating shaft 5Z, the rotor 6, the stator 7, and the bearings 8 and 9.

[0106] The rotating shaft 5Z rotates due to the rotation of the rotor 6 and transmits rotational power to the impeller 26. In other words, the rotating shaft 5Z rotates the impeller 26. The shape of the rotating shaft 5Z is cylindrical along the front-rear direction. The rotating shaft 5Z is made of stainless steel, for example. The rotating shaft 5Z is inserted into the rotor 6 and fixed to the rotor 6. The rotating shaft 5Z comprises a front end 5a, a front end face 5b, a rear end face 5c, an outer circumferential surface 5d, an axial flow path 51Z, and two valves 52.

[0107] Figure 16 is a partially enlarged schematic cross-sectional view of the pump 1Z showing the vicinity of valve 52 on the rotating shaft 5Z. In the following description, Figure 15 will be referred to together with Figure 16 as appropriate.

[0108] The axial passage 51Z is a passage for the pre-cooling liquid and is a through-hole that penetrates the rotating shaft 5Z. The axial passage 51Z is located inside the rotating shaft 5Z from the front end surface 5b to near the rear end, along the longitudinal direction. The rear end of the axial passage 51Z is branched into two and bent at a right angle along the radial direction. The axial passage 51Z comprises an inlet 511, two valve chambers 513, two seating surfaces 514, and two outlets 516.

[0109] The outlet 516 leads the pre-cooling liquid from the axial flow path 51Z. In the circumferential direction, the outlets 516 are arranged at equal intervals (180° intervals) on the outer circumferential surface 5d. In the axial direction, the outlets 516 are located between the rotor 6 and the bearing 9. That is, the outlets 516 are located behind the inlet 511 and open toward the motor chamber 41. The outlet 516 is an example of a circumferential outlet in the present invention.

[0110] The valve chamber 513 houses the corresponding valve 52. The valve chamber 513 is positioned radially along the rear end of the axial flow path 51Z. In the radial direction, the inner surface of the valve chamber 513 functions as a seating surface 514.

[0111] ● Operation of pump (4) Next, the operation of this pump 1Z will be described below, focusing on the differences from the operation of the first to third embodiments. Figures 15 and 16 will be referenced as appropriate in the following description.

[0112] Figure 17 is a schematic cross-sectional view of pump 1Z, showing the pump 1Z in the pre-cooling state. In this figure, a portion of the pre-cooling liquid flow is indicated by a thick arrow.

[0113] When pre-cooling is performed, first and second flows F1 and F2 are generated, similar to the first embodiment.

[0114] The pre-cooling liquid introduced into the pump chamber 22 also flows from the inlet 511 into the shaft passage 51Z. The pre-cooling liquid flowing into the shaft passage 51Z moves the valve body 521 backward due to its hydraulic pressure. At this time, the shaft passage 51Z (valve 52) opens. Therefore, the pre-cooling liquid that flowed into the shaft passage 51Z flows into the motor chamber 41 via the valve chamber 513 and outlet 516 (sixth flow F6). At this time, the rotating shaft 5, rotor 6, and stator 7 (motor chamber 41) are cooled by the pre-cooling liquid. The pre-cooling liquid that flows into the motor chamber 41 flows into the internal passage 25 via the bearing 9.

[0115] During the operation of this pump 1Z, the fluid being handled, introduced into the motor chamber 41 via the bearing 9, enters the outlet 516 and presses the valve body 521 against the seat surface 514. As a result, the axial passage 51Z (valve 52) closes. Consequently, backflow of the fluid being handled through the axial passage 51 is prevented. Consequently, the motor section 3Z is cooled in a shorter time compared to the motor section of a conventional pump. Therefore, the amount of pre-cooled fluid is reduced. In other words, the pre-cooling time is shortened and the amount of pre-cooled fluid is reduced.

[0116] ●Summary (4) In the above description, the axial flow path 51Z is provided with two outlets 516. The outlets 516 are located on the outer circumferential surface 5d and open toward the motor chamber 41. In this configuration, the motor section 3Z is cooled from the inside by the sixth flow F6. Therefore, in this pump 1Z, the pre-cooling time is shortened and the amount of pre-cooling liquid is reduced compared to conventional pumps.

[0117] ●Variations● Next, a modified version of the pump 1 in the first embodiment will be described below, focusing on the differences from the first embodiment. In the modified version, the configuration of the axial flow path differs from that of the first embodiment. In the following description of the modified version, for the sake of clarity, the same reference numerals as in the first embodiment and components having common functions are used, and detailed explanations are omitted.

[0118] Figure 18 is a schematic cross-sectional view of the pump 1 in a modified example. In the following description, Figures 1 and 2 will be referred to as appropriate, along with Figure 18.

[0119] The axial flow path 51 comprises two inlets 511, an outlet 512, a valve chamber 513, and a seating surface 514.

[0120] In the circumferential direction, the inlets 511 are arranged at equal intervals (180° intervals) on the outer circumferential surface 5d. In the axial direction, the inlets 511 are located between the impeller 26 and the front bracket portion 42 (housing 4). The inlets 511 open toward the pump chamber 22. In this configuration, the pre-cooling liquid is less likely to be introduced into the axial flow path 51 than in the first embodiment, but it is still introduced into the axial flow path 51, similar to the first embodiment. As a result, similar to the first embodiment, the motor portion 3 is cooled from the inside by the third flow F3. Therefore, in this pump 1, the pre-cooling time is shortened and the amount of pre-cooling liquid is reduced compared to conventional pumps.

[0121] ●Other Embodiments● In the present invention, the configurations described in each embodiment and modification may be combined with or substituted for each other to the extent that the present invention can be constructed.

[0122] In this invention, the liquid being handled is not limited to cryogenic liquids. That is, for example, the liquid being handled may be a high-temperature liquid (e.g., oil). In this case, the specific temperature is high (e.g., 150°C). Furthermore, pumps 1 to 1Z perform preheating instead of precooling, and a preheating liquid (liquid used for preheating: the liquid being handled) is introduced instead of a precooling liquid.

[0123] In the present invention, the number of axial channels 51, 51Y, and 51Z is not limited to "1".

[0124] In the present invention, the shapes of the axial channels 51, 51Y, and 51Z are not limited to a cylindrical shape. That is, for example, the shapes of the axial channels 51, 51Y, and 51Z may be multi-stage cylindrical.

[0125] In the present invention, the number of inlets 511 is not limited to "1". That is, for example, the number of inlets 511 may be "2", as shown in the modified example.

[0126] In the present invention, the inlet 511 does not have to be positioned forward of the impeller 26. That is, for example, the front end surface 5b may be positioned rearward of the front end of the impeller 26, and the inlet 511 may be positioned at the same location as the impeller 26 in the axial direction.

[0127] In the present invention, the number of outlets 512 is not limited to "1". That is, for example, the number of outlets 512 may be "2", as shown in the fourth embodiment.

[0128] In the present invention, the position of the valve chamber 513 is not limited to the position of each embodiment (the rear end and front end of the axial flow path 51, 51Y, 51Z).

[0129] In the present invention, the number of intermediate outlets 515 is not limited to "2". Furthermore, in the axial direction, the intermediate outlets 515 may be positioned between the bearing 8 and the rotor 6.

[0130] In the present invention, the shape of the valve body 521 is not limited to a spherical shape. That is, for example, the valve body 521 may be plate-shaped or conical.

[0131] In the present invention, the configuration of the valve 52 is not limited to the configuration of each embodiment, as long as it functions as a one-way valve that allows the pre-cooled liquid to pass through but prevents the handling liquid discharged from the impeller 26 from passing through. That is, for example, the valve 52 may be a duckbill valve. Also, for example, in the fourth embodiment, the valve 52 may be closed by centrifugal force.

[0132] Figure 19 is a partially enlarged schematic cross-sectional view of the vicinity of valve 52, showing another embodiment of valve 52 in the fourth embodiment.

[0133] The valve 52 includes a valve body 521 configured to open the axial passage 51Z when the rotating shaft 5Z is not rotating, and to close the axial passage 51Z when the rotating shaft 5Z is rotating, due to the centrifugal force resulting from the rotation of the rotating shaft 5Z. In this case, the outer surface of the valve chamber 513 functions as a seating surface 514. The valve body 521 is housed in the corresponding valve chamber 513 and is arranged to be radially movable. The valve body 521 does not contact the seating surface 514 by the hydraulic pressure of the pre-cooling liquid alone. Even with this configuration, the pre-cooling time is shortened and the amount of pre-cooling liquid is reduced compared to conventional pumps.

[0134] In the present invention, the valve 52 does not necessarily have to be equipped with a biasing member 522.

[0135] In the present invention, the number of auxiliary flow paths 45 and auxiliary valves 46 is not limited to "2".

[0136] In the present invention, the position of the auxiliary channel 45 is not limited to the front bracket portion 42. That is, for example, the auxiliary channel 45 may be located in the rear bracket portion 43 and / or peripheral wall portion 44 of the housing 4.

[0137] In the present invention, the shape of the auxiliary valve body 461 is not limited to a spherical shape. That is, for example, the auxiliary valve body 461 may be plate-shaped or conical.

[0138] In the present invention, the shape of the rear bracket portion 43 is not limited to a cylindrical shape. That is, for example, the shape of the rear bracket portion 43 may be a bottomed cylindrical shape having a bottom in the rearward direction. In this case, the rear bracket portion 43 may have at least one through hole that penetrates in the front-rear direction through the portion of the rear bracket portion 43 located in the rearward direction of the bearing 9 and / or the rotating shaft 5 (rear wall portion). The rear end face 5c of the rotating shaft 5 faces the rear wall portion of the rear bracket portion 43, and the outlet 512 may communicate with the internal flow path 25 through the through hole.

[0139] ●Embodiments of the present invention● Next, embodiments of the present invention as understood from the embodiments described above will be described below, with reference to the terms and reference numerals described in each embodiment.

[0140] A first embodiment of the present invention comprises an impeller (e.g., impeller 26) for sucking in and discharging a liquid to be handled, a pump chamber (e.g., pump chamber 22) for housing the impeller, and a motor section (e.g., motor sections 3-3Z) for rotating the impeller, wherein the motor section comprises a rotating shaft (e.g., rotating shafts 5, 5Y, 5Z) to which the impeller is attached, a stator (e.g., stator 7) for rotating the rotating shaft, and a motor housing (e.g., housing 4, 4X) for housing the rotating shaft and the stator, wherein the direction in which the impeller is positioned relative to the motor housing is a first direction, the direction opposite to the first direction is a second direction, and the rotating shaft has axial passages (e.g., axial passages 51, 51Y, A pump (e.g., this pump 1 to 1Z) comprises a motor casing (51Z), at least one valve (e.g., valve 52) disposed in the axial passage for opening and closing the axial passage, and a projection (e.g., front end 5a) projecting from the motor housing toward the pump chamber to which the impeller is attached, wherein the axial passage comprises at least one inlet (e.g., inlet 511) disposed in the projection, and at least one outlet (e.g., outlets 512, 516, intermediate outlet 515) disposed in the second direction from the inlet, and the valve is configured to open the axial passage when a liquid used for pre-cooling or pre-heating the motor section is introduced into the axial passage through the pump chamber, and to close the axial passage when the impeller rotates and discharges the liquid being handled. With this configuration, the pre-cooling time is shortened and the amount of pre-cooled liquid is reduced compared to conventional pumps. In addition, backflow of the handled liquid through the axial flow path is prevented during the operation of this pump.

[0141] A second embodiment of the present invention is a pump (e.g., pumps 1 to 1Y) that is the first embodiment and has a discharge port (e.g., discharge port 24) from which the handling liquid is discharged, and an internal passage (e.g., internal passage 25) that guides the handling liquid discharged from the impeller to the discharge port, wherein the outlet is an end face outlet (e.g., outlet 512) located on the end face (e.g., rear end face 5c) on the second direction side of the rotating shaft, and the axial passage is able to communicate with the internal passage via the end face outlet. With this configuration, the pre-cooling time is further reduced, and the amount of pre-cooling liquid is further decreased.

[0142] A third embodiment of the present invention is a pump (e.g., the pump 1Y, 1Z) of the first or second embodiment, wherein a portion of the fluid being handled discharged from the impeller is introduced into the internal space of the motor housing (e.g., motor chamber 41), and the outlet is a circumferential outlet (e.g., intermediate outlet 515, outlet 516) located on the outer circumferential surface of the rotating shaft (e.g., outer circumferential surface 5d) and opening toward the internal space. With this configuration, the pre-cooling time is further reduced, and the amount of pre-cooling liquid is further decreased.

[0143] A fourth embodiment of the present invention is a third embodiment, wherein the valve is a pump that opens the axial passage by the hydraulic pressure of the liquid when the liquid is introduced into the axial passage through the pump chamber, and closes the axial passage by the hydraulic pressure of the liquid discharged from the impeller when the impeller rotates and discharges the liquid being handled. This configuration ensures that the pre-cooling liquid flows reliably during pre-cooling and reliably prevents backflow of the handled liquid while the pump is operating.

[0144] A fifth embodiment of the present invention is a third embodiment, wherein the valve opens the axial passage when the rotating shaft is not rotating, and closes the axial passage by centrifugal force when the rotating shaft is rotating, in a pump (for example, this pump 1Z). With this configuration, the pre-cooling time is shortened and the amount of pre-cooled liquid is reduced compared to conventional pumps.

[0145] A sixth embodiment of the present invention is a pump that is the first embodiment, wherein the inlet is positioned in the first direction relative to the impeller. With this configuration, the pre-cooling liquid is easily introduced into the axial flow path.

[0146] A seventh embodiment of the present invention is a pump (e.g., pump 1X, 1Y) of the first embodiment, wherein a portion of the handling fluid discharged from the impeller is introduced into the internal space of the motor housing (e.g., motor chamber 41), and the motor unit comprises an auxiliary passage (e.g., auxiliary passage 45) penetrating the motor housing, and an auxiliary valve (e.g., auxiliary valve 46) disposed in the auxiliary passage for opening and closing the auxiliary passage, wherein the auxiliary valve opens the auxiliary passage by the hydraulic pressure of the liquid when the liquid is introduced into the auxiliary passage, and closes the auxiliary passage by the hydraulic pressure of the handling fluid discharged from the impeller when the impeller rotates and the handling fluid is discharged. With this configuration, the pre-cooling time is further reduced, and the amount of pre-cooling liquid is further decreased.

[0147] An eighth embodiment of the present invention is a seventh embodiment, wherein the motor unit comprises a bearing (for example, bearing 8) that rotatably supports the rotating shaft, and the auxiliary flow path is arranged radially with respect to the rotating shaft and outward from the bearing, in a pump. In this configuration, the bearing is cooled from both the inside and the outside. [Explanation of Symbols]

[0148] 1 pump 22 Pump Room 26 Impeller 3. Motor section 4. Enclosure (Motor enclosure) 41 Motor room (internal space) 5. Rotation axis 5a Front end (protrusion) 5c Rear end face (end face) 5d Outer surface 51 Axial flow path 511 Entrance 512 Exit (end exit) 52 valves 7 Status 8 bearings 1X Main pump 3X Motor Unit 4X enclosure (motor enclosure) 44 Auxiliary channel 45 Auxiliary valve 1Y Main Pump 3Y Motor Section 5Y rotation axis 51Y Axial flow path 515 Intermediate outlet (peripheral outlet) 1Z Main Pump 3Z Motor Section 5Z rotation axis 51Z Axial flow path 516 Exit (peripheral exit)

Claims

1. An impeller that sucks in and discharges the liquid being handled, A pump chamber housing the impeller, A motor unit that rotates the impeller, It has, The motor section is The rotating shaft to which the impeller is attached, A stator that rotates the aforementioned rotating shaft, A motor housing that houses the rotating shaft and the stator, Equipped with, The direction in which the impeller is positioned relative to the motor housing is the first direction, and the direction opposite to the first direction is the second direction. The aforementioned rotating shaft is An axial channel is disposed inside the rotating shaft so as to be aligned with the axial direction of the rotating shaft, At least one valve is arranged in the axial flow path and opens and closes the axial flow path, A protruding portion extends from the motor housing toward the pump chamber, to which the impeller is attached, Equipped with, The aforementioned axial flow path is At least one entrance is provided in the protruding portion, At least one outlet positioned in the second direction from the aforementioned inlet, Equipped with, The aforementioned valve, When the liquid used for pre-cooling or pre-heating the motor section is introduced into the shaft passage via the pump chamber, the shaft passage is opened, When the impeller rotates and the handling fluid is discharged, the axial flow path is closed. It is configured in such a way. pump.

2. The outlet from which the liquid being handled is discharged, An internal flow path that guides the liquid being handled, discharged from the impeller, to the discharge port, It has, The aforementioned outlet is, An end face outlet is located on the end face on the second direction side of the rotation shaft. Equipped with, The axial flow path is capable of communicating with the internal flow path via the end face outlet. The pump according to claim 1.

3. A portion of the handling fluid discharged from the impeller is introduced into the internal space of the motor housing. The aforementioned outlet is, A circumferential outlet is positioned on the outer surface of the rotating shaft and opens toward the internal space, Equipped with, The pump according to claim 1 or 2.

4. The aforementioned valve, When the liquid is introduced into the axial channel via the pump chamber, the liquid pressure of the liquid opens the axial channel. When the impeller rotates and the handling fluid is discharged, the hydraulic pressure of the handling fluid discharged from the impeller closes the axial passage. The pump according to claim 3.

5. The aforementioned valve, When the rotating shaft does not rotate, the shaft flow path is opened. When the rotating shaft rotates, the centrifugal force closes the shaft channel. The pump according to claim 3.

6. The inlet is positioned in the first direction relative to the impeller. The pump according to claim 1.

7. A portion of the handling fluid discharged from the impeller is introduced into the internal space of the motor housing. The motor section is An auxiliary channel that penetrates the motor housing, An auxiliary valve is arranged in the auxiliary flow path and opens and closes the auxiliary flow path, Equipped with, The aforementioned auxiliary valve is When the liquid is introduced into the auxiliary channel, the liquid pressure of the liquid opens the auxiliary channel. When the impeller rotates and the handling liquid is discharged, the auxiliary flow path is closed by the liquid pressure of the handling liquid discharged from the impeller. The pump according to claim 1.

8. The motor section is A bearing that rotatably supports the aforementioned rotating shaft, Equipped with, The aforementioned auxiliary channel is In the radial direction of the rotating shaft, the bearing is positioned outward from the bearing. The pump according to claim 7.

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