Fluid conveyor

Abstract

[Problem] To provide a fluid conveyor that exhibits high conveying efficiency. [Solution] This fluid conveyor 20 comprises a casing 21 and a spiral blade 22. The spiral blade 22 is fixed to an inner peripheral surface 31 of the casing 21 and protrudes inward. The spiral blade 22 is formed by spirally bending a flat bar, and extends in an axial direction 7 at a predetermined pitch 121. The protrusion width 123 of the spiral blade 22 is less than a half of the inner diameter of the casing 21. A central flow passage 34 is formed along a central axis 6 at the center of the casing 21. The fluid conveyor 20 is rotatably supported by a support mechanism and is rotationally driven by a driving device.　

Description

Fluid Conveyor

[0001] The present invention relates to a device for transporting a fluid, and more particularly to the structure of a fluid transporter used in the device.

[0002] 2. Description of the Related Art Conventionally, there have been provided devices for transporting powder, granules, etc., as well as devices for transporting liquid or gas to generate thrust.

[0003] Patent Document 1 discloses a powder conveying device for conveying powders such as wheat flour, skim milk powder, toner, etc. The powder conveying device disclosed in this document includes a cylindrical body, a rotating shaft disposed at the center of the cylindrical body, a spiral blade extending from the rotating shaft, and a motor. The motor rotates the spiral blade via the rotating shaft, and the rotated spiral blade conveys the powder.

[0004] Patent Document 2 discloses a liquid transport device used as a side thruster device for a ship. The side thruster device (liquid transport device) disclosed in this document includes a motor disposed inside a through-hole that penetrates the bottom of the ship in the left-right direction, and a propeller attached to the drive shaft of the motor. The propeller rotated by the motor transports a liquid such as seawater, thereby generating thrust.

[0005] JP 2015-174733 A JP 2024-12890 A

[0006] The powder conveying device described in Patent Document 1 includes the rotating shaft, which is disposed in the powder conveying path, thereby reducing the capacity of the conveying path. On the other hand, the side thruster device described in Patent Document 2 has a motor disposed in the through-hole, thereby reducing the cross-sectional area of ​​the through-hole, i.e., the area of ​​the flow path through which the liquid passes. As a result, conventional powder or liquid conveying devices have a problem of reduced powder or liquid conveying efficiency. Note that, in this specification, powder, granules, liquid, and gas may be collectively referred to as "fluid."

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fluid transport device that can improve the efficiency of transporting a fluid.

[0008] (1) The fluid conveying device according to the present invention comprises a cylindrical casing to which a fluid is supplied, and a spiral blade protruding from the inner peripheral surface of the casing and extending helically at a predetermined pitch along the central axis of the casing.

[0009] When the casing rotates around the central axis, the spiral blade rotates along with the casing. Because the spiral blade extends spirally along the central axis, the rotating spiral blade can move (convey) the fluid supplied to the casing from one side to the other in the direction of the central axis. Because this spiral blade protrudes from the inner peripheral surface of the casing, it does not have a rotation axis like conventional blades. Therefore, the fluid transport is not hindered by the rotation axis, and the flow path volume within the casing is larger than that of conventional fluid transport devices. As a result, the fluid transport efficiency is improved.

[0010] (2) A fluid conveying device according to the present invention comprises a cylindrical casing to which a fluid is supplied, and N (N is plural) protruding blades each protruding from the inner peripheral surface of the casing and arranged at equal intervals around the central axis of the casing, wherein the protruding blades are inclined relative to the direction of the central axis of the casing and radial directions so as to convey the fluid by rotating around the central axis.

[0011] When the casing rotates around the central axis, the protruding blades rotate together with the casing. Because the protruding blades are inclined relative to the direction of the central axis and the radial direction, the rotating protruding blades can move (convey) the fluid supplied to the casing from one side to the other in the direction of the central axis. Because these protruding blades protrude from the inner peripheral surface of the casing, they do not have a rotation axis like conventional blades. Therefore, the fluid transport is not hindered by the rotation axis, and the flow path volume within the casing is larger than that of conventional fluid transport devices. As a result, the fluid transport efficiency is improved.

[0012] (3) The N protruding blades may be arranged along N imaginary spirals extending at a predetermined pitch (P) in the direction of the central axis and displaced by P / N along the central axis.

[0013] In this configuration, the relative positions of the N protruding blades are the same as the relative positions of the multiple threads in a so-called multiple-start (N-start) screw. The N protruding blades formed in this manner can efficiently transport fluid.

[0014] (4) The number of the protruding blades may be three.

[0015] (5) The spiral blade may have a radial projection width from the casing that is less than half the inner diameter of the casing.

[0016] In this configuration, a central flow passage without spiral blades is formed around the central axis of the casing. This allows the fluid to pass through the central flow passage smoothly. Therefore, even if the fluid contains particles with relatively large outer diameters, malfunctions due to clogging of the particles are suppressed.

[0017] (6) The length of the protruding blades projecting radially from the casing may be less than half the inner diameter of the casing.

[0018] In this configuration, a central flow passage without any protruding blades is formed around the central axis of the casing. This allows the fluid to pass through the central flow passage smoothly. Therefore, even if the fluid contains particles with relatively large outer diameters, malfunctions due to clogging of the particles are suppressed.

[0019] (7) A fluid conveying device according to the present invention is used in a fluid conveying device, which includes a cylindrical casing to which a fluid is supplied, spiral blades projecting from the inner peripheral surface of the casing and extending helically at a predetermined pitch along the central axis of the casing, a support body supporting the casing so that the casing can rotate around the central axis, and a drive device disposed outside the casing and rotating the casing.

[0020] In a fluid transport device, a drive unit rotates a casing. The casing is supported by a support, allowing it to rotate smoothly. The spiral blade rotates along with the casing. The rotating spiral blade can move (transport) the fluid supplied to the casing from one side to the other in the direction of the central axis. This spiral blade protrudes from the inner circumferential surface of the casing, and does not have a rotation shaft like conventional blades. Therefore, fluid transport is not hindered by the rotation shaft, and the flow path volume within the casing is larger than in conventional fluid transport devices. As a result, fluid transport efficiency is improved.

[0021] (8) A fluid conveying device according to the present invention is used in a fluid conveying device. The fluid conveying device includes a cylindrical casing to which a fluid is supplied, N (N is plural) protruding blades each protruding from the inner peripheral surface of the casing and arranged at equal intervals around the central axis of the casing, a support that supports the casing rotatably around the central axis, and a drive device that is arranged outside the casing and rotates the casing. The protruding blades are inclined with respect to the direction of the central axis of the casing and the radial direction so as to convey the fluid by rotating around the central axis.

[0022] In a fluid transport device, a drive unit rotates a casing. The casing is supported by a support, allowing it to rotate smoothly. The protruding blades rotate together with the casing. The rotating protruding blades can move (transport) the fluid supplied to the casing from one side to the other in the direction of the central axis. Because these protruding blades protrude from the inner circumferential surface of the casing, they do not have a rotation axis like conventional blades. Therefore, the transport of the fluid is not hindered by the rotation axis, and the flow path volume within the casing is larger than in conventional fluid transport devices. As a result, the fluid transport efficiency is improved.

[0023] (9) The N protruding blades may be arranged along N imaginary spirals extending at a predetermined pitch (P) in the direction of the central axis and displaced by P / N along the central axis.

[0024] In this configuration, the relative positions of the N protruding blades are the same as the relative positions of the multiple threads in a so-called multiple-start (N-start) screw. The N protruding blades formed in this manner can efficiently transport fluid.

[0025] (10) The drive device may have a plurality of magnetic bodies arranged circumferentially on the outer peripheral surface of the casing, a plurality of excitation coils arranged circumferentially radially outward of the casing from the magnetic bodies, and a drive circuit that generates a rotating magnetic field in the excitation coils.

[0026] In this configuration, the rotating magnetic field generated by the excitation coil applies a rotational torque due to magnetic force to the casing to which the magnetic body is attached, which allows the casing to rotate without contact, thereby improving the durability of the fluid transport device.

[0027] According to the present invention, the efficiency of transporting fluid is improved.

[0028] FIG. 1 is a cross-sectional view of a fluid transporting device 10 including a fluid transporter 20 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the fluid transporter 20 according to an embodiment of the present invention. FIG. 3 is a view taken along the line III-III in FIG. 2. FIG. 4 is a perspective view of a main portion of the fluid transporter 20. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 1. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 1. FIG. 7 is a schematic circuit diagram of the fluid transporting device 10. FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 1. FIG. 9 is a perspective view of a main portion of a fluid transporter 70 according to a first modification of the embodiment of the present invention. FIG. 10 is a view taken along the line X-III in FIG. 9. FIG. 11 is a cross-sectional view of the fluid transporter 70. FIG. 12 is a diagram illustrating the positional relationship of protruding blades 71, 72, and 73 and the positional relationship of imaginary spirals 74, 75, and 76. FIG. 13 is a cross-sectional view of a fluid transporting device 80 according to a second modification of the present invention, including the fluid transporter 20 according to an embodiment of the present invention. Fig. 14 is a cross-sectional view of a fluid transporting device 90 according to Modification 3, which includes the fluid transporting device 20 according to the embodiment of the present invention. Fig. 15 is a cross-sectional view of a fluid transporting device 100 according to Modification 4, which includes the fluid transporting device 20 according to the embodiment of the present invention.

[0029] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. Note that this embodiment is merely one aspect of the fluid transporter and fluid transport device according to the present invention, and it goes without saying that the implementation may be changed without departing from the spirit and scope of the present invention.

[0030] [Fluid transport device 10]

[0031] FIG. 1 is a cross-sectional view of a fluid transporting device 10 including a fluid transporter 20 according to an embodiment of the present invention.

[0032] The fluid transport device 10 is disposed between two pipes 11 through which fluids are supplied. In this embodiment, the concept of fluid includes liquids, gases, powders, and granules. Liquids include water, crude oil, petroleum products, and alcohol. Petroleum products include heavy oil, light oil, gasoline, benzene, and toluene. Gases include natural gas, fuel gas, air, and rare gases. Powders include grain flour, skim milk powder, and toner. Granules include grains, resin pellets, and crushed ore. Grains include corn, rice, and beans. The fluid transport device 10 is used, for example, to transport crude oil, natural gas, and grains; transport fuel gas within cities; and transport water, alcohol, benzene, and rare gases within factories. It is also used as a propulsion engine for ships and an air-conditioning system for buildings.

[0033] When the fluid transporting device 10 is operated, the fluid in the pipe 11 is transported along the axial direction 7 in a manner described below. A feature of the fluid transporting device 10 is the structure of the fluid transporter 20, which will be described in detail later. The fluid transporting efficiency is improved when the fluid transporter 20 has the structure described below.

[0034] As shown in Figure 1, the fluid conveying device 10 comprises a fluid conveyer 20, a support mechanism 40 that supports the fluid conveyer 20, a drive device 50 that rotates the fluid conveyer 20, and a joint 60 that connects the fluid conveyer 20 to the above-mentioned pipe 11.

[0035] [Fluid conveyor 20]

[0036] Fig. 2 is a cross-sectional view of the fluid transporter 20 according to the embodiment of the present invention. Fig. 3 is a view taken along the line III-III in Fig. 2. Fig. 4 is a perspective view of the main part of the fluid transporter 20, with a part cut away.

[0037] As shown in Fig. 2, the fluid conveyer 20 has a casing 21 and a spiral blade 22. In Fig. 1 and Fig. 2, the spiral blade 22 is shown as a side view rather than a cross-sectional view. In these figures, a hatched area 33 is a connection portion (welded portion) between the spiral blade 22 and the inner circumferential surface 31 of the casing 21.

[0038] The casing 21 is a cylindrical member having an inner peripheral surface 31 and an outer peripheral surface 32. In the figure, a dashed dotted line 6 indicates the central axis of the casing 21. The direction of this central axis 6 coincides with the axial direction 7. The casing 21 is made of a ferrous material such as stainless steel, or a non-ferrous metal such as an aluminum alloy. However, in this embodiment, the casing 21 is made of a stainless steel pipe that is commercially available as a standard product. The material of the casing 21 is not particularly limited and is determined appropriately depending on the properties of the fluid to be transported.

[0039] The inner diameter 111 and the wall thickness 117 of the casing 21 are determined depending on the type of fluid to be transported and the required transport amount. The outer diameter 112 of the casing 21 is determined by the inner diameter 111 and the wall thickness 117 of the casing 21.

[0040] The spiral blade 22 is fixed to the inner peripheral surface 31 of the casing 21 and protrudes inward from the inner peripheral surface 31. In this embodiment, the material constituting the spiral blade 22 is the same as that of the casing 21, and is made of a ferrous material such as stainless steel or a non-ferrous metal such as an aluminum alloy. The spiral blade 22 is made of, for example, a rectangular flat bar. In this embodiment, the spiral blade 22 is formed by bending this flat bar into a spiral shape by press working. The region 33 of the spiral blade 22 is welded to the inner peripheral surface 31 of the casing 21, and the spiral blade 22 is formed integrally with the casing 21.

[0041] As shown in Figures 2 to 4, the spiral blade 22 extends helically along the axial direction 7 of the casing 21. As shown in Figure 2, the spiral shape of the spiral blade 22 is determined by a helix angle α. In this embodiment, the helix angle α refers to the inclination of the helix with respect to the imaginary cross-section 12 of the casing 21 (a plane perpendicular to the central axis 6). The helix angle α determines the pitch 121 of the spiral blade 22. The pitch 121 is the length of one revolution of the spiral in the axial direction 7. The helical shape of the spiral blade 22 may be determined by this pitch 121. The wall thickness 26, total length 118, and helix angle α of the spiral blade 22 are determined depending on the type of fluid to be transported and the required transport amount.

[0042] The height of the spiral blade 22, i.e., the protruding width 123 of the spiral blade 22 in the radial direction 8, is less than half the inner diameter 111 (less than the radius of curvature of the inner circumferential surface 31) at any portion in the axial direction 7. This forms a central flow passage 34 around the central axis 6. In Figures 2 and 4, the central flow passage 34 is indicated by a two-dot chain line. The central flow passage 34 is formed by the inner edge 25 of the spiral blade 22 and extends along the axial direction 7.

[0043] The protrusion width 123 is not particularly limited, but is determined appropriately depending on the properties of the fluid. In this embodiment, the protrusion width 123 is determined so that the diameter 113 of the central flow path 34 is larger than the maximum diameter of the granular material being transported. This prevents the fluid from clogging inside the casing 21, even if the fluid being transported is granular.

[0044] [Support mechanism 40]

[0045] FIG. 5 is a cross-sectional view taken along line VV in FIG. 1, showing the structure of the support mechanism 40. As shown in FIG.

[0046] 1 and 5, the support mechanism 40 includes a frame 41 and a plurality of rolling elements 42 supported by the frame 41. The plurality of rolling elements 42 function as a support body that supports the fluid conveyer 20.

[0047] In this embodiment, the frame 41 is made of a rectangular tubular member. The frame 41 houses the fluid conveyor 20 and surrounds the casing 21 in the circumferential direction 9. The frame 41 is fixed to a building such as a factory or the hull of a ship via a bracket or the like (not shown). Note that the frame 41 may have another shape, such as a cylindrical shape, as long as it can surround the casing 21 in the circumferential direction 9.

[0048] As shown in Fig. 1, a plurality of rolling elements 42 are arranged at one end and the other end of the casing 21 in the axial direction 7. In this embodiment, four rolling elements 42 are arranged around one end of the casing 21, and similarly, four rolling elements 42 are arranged around the other end of the casing 21. While each of the one end and the other end is supported by four rolling elements 42, the number of rolling elements 42 supporting the one end and the other end is not particularly limited, and may be three or more. As shown in Fig. 5, in this embodiment, the rolling elements 42 are arranged evenly (at 90-degree intervals) in the circumferential direction 9.

[0049] In this embodiment, the rolling element 42 is a disk member having a predetermined thickness, and is supported by a support shaft 44. This support shaft 44 is arranged along the central axis 6. A through hole 43 is provided in the center of the rolling element 42, and the support shaft 44 is inserted into this through hole 43. The rolling element 42 is rotatable around the support shaft 44. In this embodiment, both ends of the support shaft 44 are supported by fixing members 45, and the support shaft 44 is fixed to the frame 41 via the fixing members 45.

[0050] The peripheral surface of each rolling element 42 abuts against the outer peripheral surface 32 of the casing 21, thereby allowing the fluid conveying device 20 to rotate smoothly around the central axis 6. Since the casing 21 is in rolling contact with the rolling elements 42, resistance to the rotation of the casing 21 is reduced. This in turn improves the durability of the fluid conveying device 20 and the fluid conveying device 10. Note that the rolling elements 42 do not need to be disk members, and may be rollers or spheres. In short, the rolling elements 42 may be any elements that are in rolling contact with the casing 21.

[0051] [Driver 50]

[0052] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 1, showing the structure of the driving device 50. Fig. 7 is a schematic circuit diagram of the fluid transporting device 10.

[0053] The driving device 50 includes the mounting member 23 and the plurality of magnetic bodies 24 shown in Figures 2 and 1, the holding member 52, the stator core 59, and the plurality of exciting coils 51 shown in Figures 1 and 6, and the driving circuit 53 shown in Figure 7. The mounting member 23 and the plurality of magnetic bodies 24 are provided on the casing 21 of the fluid conveyer 20, as shown in Figure 2. The holding member 52 and the stator core 59 are provided on the frame 41 of the support mechanism 40, as shown in Figure 1.

[0054] 2 and 3 , the mounting member 23 is a hollow ring-shaped member that is attached to the outer peripheral surface 32 of the casing 21. In this embodiment, the mounting member 23 is fixed to the casing 21 via an adhesive or other known fastener. The mounting member 23 is disposed in the center of the casing 21 in the axial direction 7, i.e., at or near the center of gravity of the casing 21. A plurality of magnetic bodies 24 are housed and fixed inside the mounting member 23. That is, the magnetic bodies 24 are fixed to the casing 21.

[0055] The magnetic bodies 24 are typically permanent magnets, but may also be magnetized metal bodies. As shown in Figures 3 and 6, the multiple magnetic bodies 24 are evenly arranged along the circumferential direction 9. In this embodiment, as shown in Figure 3, four magnetic bodies 24 are arranged at 90-degree intervals in the circumferential direction 9. The number of magnetic bodies 24 is not limited to four, and may be two or more.

[0056] The stator core 59 according to this embodiment (see FIGS. 1 and 6) has a known structure and includes a ring-shaped portion and a plurality of teeth protruding from the ring-shaped portion. Conductive wires are wound around the teeth to form the excitation coils 51.

[0057] 6, the multiple excitation coils 51 are arranged radially outward of the casing 21 relative to the magnetic body 24. In this embodiment, three excitation coils 51 are formed, and these are arranged evenly (at 120-degree intervals) along the circumferential direction 9. Note that the number of excitation coils 51 is not limited to three, and may be two or more.

[0058] The holding member 52 is a hollow ring-shaped member, and is fixed to the frame 41 via a known fixing means. In this embodiment, the holding member 52 is made of resin and has insulating properties. In other words, the holding member 52 is a so-called insulator, and the stator core 59 and the exciting coil 51 are housed within the holding member 52.

[0059] In this embodiment, the inner diameter 114 of the holding member 52 is slightly larger than the outer diameter 115 of the mounting member 23, and the holding member 52 does not come into contact with the mounting member 23. Therefore, even if the casing 21 rotates around the central axis 6, the holding member 52 or the exciting coil 51 does not hinder the rotation of the casing 21.

[0060] 7, the holding member 52 has a connector 54. The connector 54 is electrically connected to the excitation coil 51 by a lead wire 55. One end of a cable 56 is connected to the connector 54.

[0061] The drive circuit 53 is realized by a printed circuit board 57 (see FIG. 6) and various electronic components (not shown) mounted on the printed circuit board 57 .

[0062] 6, the printed circuit board 57 is attached to the frame 41 via screws or the like. In this embodiment, the printed circuit board 57 is attached to the outer surface of the frame 41. However, the printed circuit board 57 may also be attached to the inner surface of the frame 41.

[0063] The various electronic components include a connector 58 (see FIG. 7), resistors, capacitors, diodes, coils, ICs, etc. The other end of the cable 56 is connected to the connector 58, and the printed circuit board 57 is electrically connected to the excitation coil 51 through the cable 56.

[0064] The IC may be, for example, a commercially available driver IC for a three-phase AC motor. Drive circuit 53 (driver IC) converts power supplied from a power supply (not shown) into three-phase AC power and supplies it to excitation coil 51. The excitation coil 51, supplied with the three-phase AC power, generates a rotating magnetic field around casing 21. Because magnetic body 24 is provided in casing 21, the formed rotating magnetic field and the magnetic force generated by magnetic body 24 cause casing 21 to rotate around central axis 6. Printed circuit board 57, on which various electronic components are mounted, functions as a control circuit, while excitation coil 51 functions as a so-called load.

[0065] The power source may be an external power source supplied to the fluid transporting device 10 from a facility such as a factory, or may be an internal power source such as a battery attached to the fluid transporting device 10.

[0066] [Joint 60]

[0067] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 1, showing the joint 60. As shown in FIG.

[0068] The joint 60 is a so-called swivel joint, and in this embodiment, a standard product (a commercially available product) is used. As shown in the figure, the joint 60 connects the fixed pipe 11 and the casing 21, which rotates relative to the pipe 11. The joint 60 is attached to both ends of the casing 21 in the axial direction 7. The joint 60 is fixed to the frame 41 in a manner described below, and together with the support mechanism 40, supports the casing 21 rotatably.

[0069] The joint 60 includes an outer cylinder 61, an inner cylinder 62 (see FIG. 1), a seal member 63, and a filter 68 (see FIG. 1). As shown in FIG. 1, the seal member 63 has a flange 65 and a plurality of protrusions 64, which are integrally formed in this embodiment. The protrusions 64 abut against the outer peripheral surface 32 of the casing 21. The protrusions 64 are aligned along the axial direction 7. The seal member 63 is fixed by sandwiching the flange 65 between the outer cylinder 61 and the inner cylinder 62.

[0070] The outer cylinder 61 is fixed to the frame 41 via screws or other known fixing means. The outer cylinder 61 and the inner cylinder 62 have a first connection port 66 and a second connection port 67 located on the opposite side. The casing 21 is inserted into the first connection port 66, and the pipe 11 is inserted into the second connection port 67, with the casing 21 facing the pipe 11 across the filter 68. A seal member may also be provided on the second connection port 67 side.

[0071] The filter 68 typically has a mesh structure and prevents foreign matter from entering the casing 21. The filter 68 may be attached only to the side of the casing 21 where the fluid flows in.

[0072] [Operation of fluid transport device 10]

[0073] When three-phase AC power is supplied to the excitation coil 51 by the drive circuit 53, a rotating magnetic field is formed around the casing 21. A magnetic force acts on the magnetic body 24 in this rotating magnetic field, causing the casing 21 to rotate. The spiral blade 22 rotates together with the casing 21. The rotating spiral blade 22 causes a helical vortex to form in the fluid, transporting the fluid flowing into the casing 21 from one side to the other side.

[0074] The direction in which the fluid is transported is determined by the direction of rotation of the casing 21 and the spiral blade 22. The direction of rotation of the casing 21 and the spiral blade 22 is determined by the direction of the rotating magnetic field formed by the excitation coil 51. The direction of the rotating magnetic field is controlled by the drive circuit 53 (driver IC), so the fluid transport device 10 can arbitrarily adjust the direction in which the fluid is transported.

[0075] [Effects of the embodiment]

[0076] 1 and 2, the spiral blade 22 is provided to protrude from the inner peripheral surface 31 of the casing 21, so that a rotary shaft having a conventional blade is not present inside the casing 21. Therefore, compared with the conventional fluid transporting device, the cross-sectional area and capacity of the flow path for the transported fluid are larger, and as a result, the transport efficiency of the fluid transporter 20 or the fluid transporting device 10 is improved.

[0077] In addition, since the spiral blade 22 protrudes from the inner peripheral surface 31 of the casing 21, no gap is created between the spiral blade 22 and the inner peripheral surface 31 of the casing 21. This has the advantage that the conveyed fluid does not get stuck between the spiral blade 22 and the inner peripheral surface 31 of the casing 21.

[0078] In this embodiment, the central flow passage 34 is formed around the central axis 6 of the casing 21, and the fluid is smoothly transported through the central flow passage 34. Therefore, even if the fluid contains particles with a relatively large outer diameter, malfunctions due to clogging of the particles are suppressed.

[0079] In this embodiment, the rotating magnetic field generated by the excitation coil 51 applies a rotational torque to the casing 21 to which the magnetic body 24 is attached. That is, the casing 21 is rotated without contact, rather than via a gear or belt. Therefore, the durability of the fluid transport device 10 is improved.

[0080] [Modification 1]

[0081] Fig. 9 is a partially cutaway perspective view of a main part of a fluid transporter 70 according to Modification 1 of this embodiment, Fig. 10 is a view taken along the X-arrow line in Fig. 9, and Fig. 11 is a cross-sectional view of the fluid transporter 70.

[0082] Fluid conveying device 70 according to this modification has protruding blades 71, 72, and 73 instead of spiral blade 22 (see FIGS. 2 and 4). In the following description, the same reference numerals are used for components similar to those of fluid conveying device 10, and description thereof will be omitted.

[0083] The fluid conveying device 10 includes a fluid conveying device 70 (see FIG. 9), a support mechanism 40, a drive device 50, and a joint 60 (see FIG. 1). The support mechanism 40 supports the fluid conveying device 70 rotatably around a central axis 6. The drive device 50 rotates the fluid conveying device 70. The joint 60 connects the fluid conveying device 70 to the pipe 11.

[0084] 9 to 11, the fluid conveying device 70 has a casing 21 and three protruding blades 71, 72, and 73. The number N of the protruding blades is not limited to three, but may be two or more. In other words, N is an integer of two or more.

[0085] 9 and 10 , the protruding blade 71 has an outer edge 130 (see FIG. 10 ) that runs along the inner circumferential surface 31 of the casing 21, an inner edge 131, a pair of side edges 132, 133, and a pair of spiral surfaces 134, 135. The spiral surface 134 and the spiral surface 135 are opposite sides of each other. In this modification, the thickness 122 of the protruding blade 71 is the same as the thickness 26 of the spiral blade 22 according to the above embodiment. The side edges 132, 133 are continuous with both ends of the inner edge 131 and are also continuous with the inner circumferential surface 31.

[0086] The protruding blades 72 and 73 have the same shape as the protruding blade 71. The protruding blade 72 has an outer edge 140, an inner edge 141, a pair of side edges 142 and 143, and a pair of helical surfaces 144 and 145, with the helical surfaces 144 and 145 being reversed. The protruding blade 73 has an outer edge 150, an inner edge 151, a pair of side edges 152 and 153, and a pair of helical surfaces 154 and 155, with the helical surfaces 154 and 155 being reversed. The outer edges 130, 140, and 150 correspond to one another, and the inner edges 131, 141, and 151 correspond to one another. The side edges 132, 142, and 152 correspond to one another, and the side edges 133, 143, and 153 correspond to one another. The helical surfaces 134, 144, 154 correspond to one another, and the helical surfaces 135, 145, 155 correspond to one another.

[0087] In FIG. 9, the hatched areas 77 correspond to the outer edges 130, 140, and 150, and these areas 77 are the connection portions (welded portions) between the protruding blades 71, 72, and 73 and the inner peripheral surface 31 of the casing 21.

[0088] As shown in Figure 10, three protruding blades 71, 72, and 73 are fixed to the inner circumferential surface 31 of the casing 21 and each protrude inward from the inner circumferential surface 31. In this modified example, the three protruding blades 71, 72, and 73 are arranged at equal intervals (120-degree intervals) around the central axis 6. The protruding blades 71, 72, and 73 are made of the same material as the casing 21. The protruding blades 71, 72, and 73 are made of, for example, a rectangular flat bar. The protruding blades 71, 72, and 73 are formed by bending this flat bar by press working, as shown in Figure 9. The above-mentioned regions 77 of the protruding blades 71, 72, and 73 are welded to the inner circumferential surface 31 of the casing 21, and the protruding blades 71, 72, and 73 are formed integrally with the casing 21.

[0089] As shown in Fig. 10 , the protruding length 79 of the protruding vanes 71 is designed appropriately depending on the properties of the fluid being conveyed. The protruding length 79 is constant in the circumferential direction 9, and in this modification, the protruding length 79 is less than half the inner diameter 111 of the casing 21 (less than the radius of curvature of the inner circumferential surface 31). This forms a central flow passage 125 around the central axis 6. In Fig. 9 , the central flow passage 125 is indicated by a two-dot chain line. The central flow passage 125 is formed by the inner sides 131, 141, and 151 of the protruding vanes 71, 72, and 73, and extends along the axial direction 7.

[0090] As shown in Figure 10, the side edges 132 and 133 of the protruding vane 71 each extend along the radial direction 8. The angle between the direction in which the side edge 132 extends and the direction in which the side edge 133 extends is 120 degrees. The same is true for the protruding vanes 72 and 73. In this modified example, the side edge 133 of the protruding vane 71 is separated from the side edge 142 of the protruding vane 72 by a distance 78 in the circumferential direction 9. The same is true for the relationship between the side edge 143 of the protruding vane 72 and the side edge 152 of the protruding vane 73, and the relationship between the side edge 153 of the protruding vane 73 and the side edge 132 of the protruding vane 71. This distance 78 can be set as appropriate.

[0091] FIG. 12 is a diagram illustrating the positional relationship of the protruding blades 71, 72, and 73 in the axial direction 7 and the positional relationship of the virtual spirals 74, 75, and 76 that serve as their reference.

[0092] In this modification, the protruding blades 71, 72, and 73 form a so-called triple helix, as shown in Fig. 9. That is, the protruding blades 71, 72, and 73 are arranged in a positional relationship similar to the positional relationship between the threads of a triple-start screw. Fig. 12 shows a schematic diagram of the positional relationship between the protruding blades 71, 72, and 73.

[0093] A triple-thread thread is virtually formed on the inside of the casing 21. In the figure, reference numerals 74, 75, and 76 indicate the trajectories of the threads developed on a plane, and in this specification, these are particularly referred to as a first imaginary helix 74, a second imaginary helix 75, and a third imaginary helix 76. Therefore, the pitch 124 (corresponding to "pitch (P)" in the claims) of the first imaginary helix 74, the second imaginary helix 75, and the third imaginary helix 76 is the same, and the first imaginary helix 74 and the second imaginary helix 75 are relatively displaced in the axial direction 6 by one-third of the pitch 124 (corresponding to "P / N" in the claims). The positional relationship between the second imaginary helix 75 and the third imaginary helix 76 and the positional relationship between the third imaginary helix 76 and the first imaginary helix 74 are also similar. In other words, the first imaginary spiral 74 , the second imaginary spiral 75 and the third imaginary spiral 76 are displaced relative to each other by an angle of 120 degrees around the central axis 6 .

[0094] In the figure, dashed double-dashed lines 71, 72, 73 indicate the positions of protruding blades 71, 72, and 73 arranged along the first imaginary spiral 74, second imaginary spiral 75, and third imaginary spiral 76, respectively.

[0095] The helical surfaces 134, 135 of the protruding vane 71 extend along a first imaginary spiral 74. Therefore, the protruding vane 71 is inclined with respect to the axial direction 7 and the radial direction 8. This inclination angle is defined by the angle (helical angle α) of the first imaginary spiral 74 with respect to the imaginary cross-section 12, as shown in Figure 11. Similarly, the helical surfaces 144, 145 of the protruding vane 72 extend along a second imaginary spiral 75, and the helical surfaces 154, 155 of the protruding vane 73 extend along a third imaginary spiral 76.

[0096] As shown in Fig. 9, the protruding vanes 71, 72, and 73 are arranged so as to divide the inner peripheral surface 31 of the casing 21 into three equal parts in the circumferential direction. Therefore, as shown in Fig. 12, the length 126 (the distance between the side edges 132 and 133) of the protruding vane 71 extending in the axial direction 7 is approximately one-third of the pitch 124 of the first imaginary spiral 74. The same is true for the length 126 of the protruding vanes 72 and 73 extending in the axial direction 7.

[0097] [Effects of Modification Example 1]

[0098] 9 to 11, the protruding blades 71, 72, 73 are inclined with respect to the axial direction 7 and the radial direction 8, and therefore the rotating protruding blades 71, 72, 73 can transport the fluid from one side of the axial direction 7 to the other. The protruding blades 71, 72, 73 are provided to protrude from the inner circumferential surface 31 of the casing 21, and therefore a rotating shaft having conventional blades is not present inside the casing 21. Therefore, compared with conventional fluid transport devices, the cross-sectional area and capacity of the flow path for the transported fluid are larger, and as a result, the transport efficiency of the fluid transporter 70 or the fluid transport device 10 is improved.

[0099] Since the protruding blades 71, 72, and 73 extend along imaginary spirals 74, 75, and 76 (see FIG. 12), the three protruding blades 71, 72, and 73 form part of the threads of a triple-start screw. Therefore, the fluid conveyer 70 can convey fluid efficiently.

[0100] In addition, because the protruding blades 71, 72, 73 are provided to protrude from the inner peripheral surface 31 of the casing 21, no gaps are formed between the protruding blades 71, 72, 73 and the inner peripheral surface 31 of the casing 21. This has the advantage that the conveyed fluid does not get stuck between the protruding blades 71, 72, 73 and the inner peripheral surface 31 of the casing 21.

[0101] In this modification, a central flow passage 125 is formed around the central axis 6 of the casing 21 (see FIG. 9), and the fluid is smoothly transported through the central flow passage 125. Therefore, even if the fluid contains particles with a relatively large outer diameter, malfunctions due to clogging of the particles are suppressed.

[0102] In the fluid transporter 70 according to this modification, the protruding vanes 71, 72, and 73 extend along imaginary spirals 74, 75, and 76, and have a curved shape, but the protruding vanes 71, 72, and 73 may be flat. Making the protruding vanes 71, 72, and 73 flat facilitates the manufacture of the fluid transporter 70.

[0103] [Modification 2]

[0104] FIG. 13 is a cross-sectional view of a fluid transporting device 80 according to Modification 2, which includes the fluid transporter 20 according to the embodiment.

[0105] The fluid conveying device 80 employs a pair of bearings 81 in place of the support mechanism 40 (see FIG. 1). The pair of bearings 81 function as supports that support the fluid conveyer 20. Note that the configurations other than those described below are the same as the configurations described in the above embodiment, and therefore the same components as those in the above embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0106] As shown in FIG. 13, the fluid transporting device 80 includes a fluid transporter 20 , a driving device 50 , a joint 60 , and a pair of bearings 81 .

[0107] One bearing 81 is located at one end of the casing 21 in the axial direction 7, and the other bearing 81 is located at the other end of the casing 21. The magnetic body 24 is located between the pair of bearings 81 in the axial direction 7. The bearing 81 includes an outer ring 82, an inner ring (not shown), a cage (not shown), and a plurality of rolling elements 83. The rolling elements 83 are balls or needles. The cage positions the rolling elements 83 and holds the rolling elements 83 rotatably. A standard product (commercially available product) can be used as the bearing 81.

[0108] [Modification 3]

[0109] FIG. 14 is a cross-sectional view of a fluid transporting device 90 according to Modification 3, which includes the fluid transporter 20 according to the embodiment.

[0110] The fluid transport device 90 has a motor 94, a drive gear 96, and a connecting gear 92, and this mechanism rotates the casing 21. Note that the configuration other than that described below is the same as the configuration described in the above embodiment, and therefore the same components as those in the above embodiment are given the same reference numerals and their description will be omitted.

[0111] 14, the fluid conveying device 90 includes a fluid conveyer 20, a support mechanism 40, a joint 60, and a driving device 93. The driving device 93 includes a connecting gear 92 provided on the fluid conveyer 20, and a motor 94, a driving gear 96, and a printed circuit board 97 provided on the frame 41 side.

[0112] The connecting gear 92 is ring-shaped and fixed to the outer circumferential surface 32 of the casing 21. The motor 94 may be a DC motor or an AC motor. The drive gear 96 is fixed to a drive shaft 95 of the motor 94. The drive gear 96 is engaged with the connecting gear 92, and when the drive gear 96 rotates together with the drive shaft 95, the casing 21 rotates via the connecting gear 92.

[0113] Various electronic components are mounted on the printed circuit board 97. These electronic components include connectors, resistors, capacitors, diodes, coils, and ICs. Lead wires extending from the motor 94 are connected to the connectors. These lead wires electrically connect the motor 94 and the printed circuit board 97. The ICs are, for example, commercially available motor driver ICs.

[0114] A drive circuit for the motor 94 is formed by the printed circuit board 97 and various electronic components mounted on the printed circuit board 97. This drive circuit converts power supplied from a power supply (not shown) into drive power such as pulse power or three-phase AC power and supplies it to the motor 94. When drive power is supplied to the motor 94, the casing 21 rotates as described above, and the spiral blade 22 rotating together with the casing 21 transports the fluid.

[0115] [Effects of Modification 3]

[0116] The casing 21 can be rotated by a simple configuration of the motor 94 and the gears 92 and 96 .

[0117] [Modification 4]

[0118] FIG. 15 is a cross-sectional view of a fluid transporting device 100 according to a fourth modification, which includes a fluid transporter 20 according to the embodiment.

[0119] In the fluid transporting device 10 described in the above embodiment, the casing 21 is rotated by the excitation coil 51 and the magnetic body 24, whereas in the fluid transporting device 100 described in this modification, the casing 21 is rotated by the motor 94, the drive pulley 103, the driven pulley 104, and the endless belt 105. Note that the configuration other than that described below is the same as the configuration described in the above embodiment and the modification. The same components as those in the above embodiment and the modification are assigned the same reference numerals, and description thereof will be omitted.

[0120] The fluid conveying device 100 includes a fluid conveying device 20, a support mechanism 40, a joint 60, and a driving device 102. The driving device 102 includes a driven pulley 104 on the fluid conveying device 20 side, and a motor 94, a driving pulley 103, an endless belt 105, and a printed circuit board 97 on the frame 41 side.

[0121] The driven pulley 104 is fixed to the outer peripheral surface 32 of the casing 21. The drive pulley 103 is fixed to the drive shaft 95 of the motor 94. The endless belt 105 is wound around the drive pulley 103 and the driven pulley 104. When the drive pulley 103 rotates, the driven pulley 104 and the casing 21 rotate via the endless belt 105.

[0122] [Effects of Modification 4]

[0123] The casing 21 can be rotated by a simple configuration of the motor 94, pulleys 103 and 104, and endless belt 105.

[0124] [Other Modifications]

[0125] In the above embodiment and each modified example, the protruding width 123 of the spiral blade 22 and the protruding length 79 of the protruding blades 71, 72, 73 are set to less than half the inner diameter 111 of the casing 21, and central flow passages 34, 125 are formed, but the protruding width 123 and the protruding length 79 may be set to the same as half the inner diameter 111 of the casing 21, and central flow passages 34, 125 may not be formed.

[0126] In the above embodiment, the casing 21 is rotatably supported by the support mechanism 40 and the joint 60. However, when the joint 60 is used, the casing 21 may be rotatably supported only by the joint 60. The joint 60 functions as a support that supports the fluid conveyer 20.

[0127] In the above embodiment, the fluid transport device 10 is provided with a joint 60, but if the fluid transport device 10 is not connected to a pipe 11, such as when used as a propulsion unit for a ship, the fluid transport device 10 may not be provided with a joint 60.

[0128] In the above embodiment, the casing 21 is supported via the rolling elements 42 and the bearings 81, but instead of these, the casing 21 may be rotatably supported by an air bearing using compressed air or a bushing.

[0129] In the above embodiment and each modified example, the casing 21, spiral blade 22, and protruding blades 71, 72, and 73 are made of metal. However, the casing 21, spiral blade 22, and protruding blades 71, 72, and 73 may also be made of resin. For example, the casing 21, spiral blade 22, and protruding blades 71, 72, and 73 may be manufactured from fiber reinforced plastic (FPR). Typically, when the fluid being transported is corrosive to metal and has low transport resistance, the casing 21, spiral blade 22, and protruding blades 71, 72, and 73 are made of resin.

[0130] DESCRIPTION OF SYMBOLS 6: Central axis 7: Axial direction 8: Radial direction 9: Circumferential direction 10, 80, 90, 100: Fluid conveying device 11: Pipe 20, 70: Fluid conveyer 21: Casing 22: Spiral blade 24: Magnetic body 31: Inner peripheral surface 32: Outer peripheral surface 34, 125: Central flow path 40: Support mechanism 41: Frame 42, 83: Rolling body (support) 50, 93, 102: Drive device 51: Excitation coil 53: Drive circuit 57, 97: Printed circuit board 60: Joint 63: Sealing member 68: Filter 71, 72, 73: Protruding blade 79: Protruding length 81: Bearing 111: Inner diameter 112: Outer diameter 121, 124: Pitch 123: Protruding width

Claims

1. A fluid conveying device comprising: a cylindrical casing to which a fluid is supplied; and a spiral blade protruding from the inner peripheral surface of the casing and extending helically at a predetermined pitch along the central axis of the casing.

2. A fluid conveying device comprising: a cylindrical casing to which a fluid is supplied; and N (N is plural) protruding blades each protruding from the inner peripheral surface of the casing and arranged at equal intervals around the central axis of the casing, wherein the protruding blades are inclined relative to the direction of the central axis of the casing and radially in order to convey the fluid by rotating around the central axis.

3. A fluid conveyor as described in claim 2, wherein the N protruding blades extend in the direction of the central axis at a predetermined pitch (P) and are arranged along N imaginary spirals formed by displacing the N / N along the central axis.

4. The fluid transporter according to claim 3, wherein the number of said protruding blades is three.

5. A fluid conveyor according to claim 1, wherein the radial projection width of said spiral blade from said casing is less than half the inner diameter of said casing.

6. A fluid conveyer according to any one of claims 2 to 4, wherein the length of the protruding blades projecting radially from the casing is less than half the inner diameter of the casing.

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