Abstract
The disclosed embodiment is related to a manufacturing method of a die-formed 3-dimensional plastic impeller of a centrifugal pump and the impeller manufactured thereby, including a mold for twisted blade and a mold for impeller outlet, the mold for twisted blade is configured to form a twisted blade portion of each blade of the impeller, the mold for impeller outlet is configured to form a rear portion of each blade, a hub rim part of the impeller, and a shroud rim part of the impeller so that the hub rim part, the shroud rim part, and the blades are formed in a single piece at the same molding process.
Claims
1. A manufacturing method of a die-formed 3-dimensional plastic impeller of a centrifugal pump, characterized in that, a hub of the impeller comprises a hub rim part and an inner hub, the hub rim part has a hub hole, a shroud of the impeller comprises a shroud rim part and an inner shroud, the shroud rim part has a shroud hole, a plurality of blades of the impeller each have a twisted blade portion located between the hub hole of the hub rim part and the shroud hole of the shroud rim part; using a mold for twisted blade and a mold for impeller outlet to form the impeller; the mold for twisted blade comprises a fixed die and a moving die, using the fixed die and the moving die placed through the hub hole and the shroud hole to form the twisted blade portions, wherein the twisted blade portions are arranged in circle at a central portion of the shroud and the hub and are formed above the central portion; using the mold for impeller outlet to integrally form the rest portion of the blades other than the twisted blade portions as well as the hub rim part used to bear power transmission; wherein the shroud hole of the shroud rim part and the hub hole of the hub rim part are respectively configured for the inner hub and the inner shroud to be disposed thereto by heat welding or melting rods, thereby together forming the impeller.
2. The manufacturing method according to claim 1, characterized in that, the hub rim part comprises a power transmission seat.
3. The manufacturing method according to claim 1, characterized in that, the mold for impeller outlet has a hub slide and a shroud slide that are radially slidable, the hub slide has a hub slide surface configured for forming an inner surface of the hub rim part facing towards the shroud rim part, and the shroud slide has a shroud slide surface configured to form an inner surface of the shroud rim part facing towards the hub rim part, the hub slide surface is a flat surface configured to form the inner surface of the hub rim part to be a flat surface, and the shroud slide surface is a convex conical surface configured to form the inner surface of the shroud rim part to be a concave conical surface.
4. The manufacturing method according to claim 1, characterized in that, the mold for impeller outlet has a hub slide and a shroud slide that are radially slidable, the hub slide has a hub slide surface configured to form an inner surface of the hub rim part facing towards the shroud rim part, and the shroud slide has a shroud slide surface configured to form an inner surface of the shroud rim part facing towards the hub rim part, the hub slide surface is a convex conical surface configured to form the inner surface of the hub rim part to be a concave conical surface, and the shroud slide surface is a flat surface configured to form the inner surface of the shroud rim part to be a flat surface.
5. The manufacturing method according to claim 1, characterized in that, a shroud line and a hub line of the rest portion of each of the blades other than the twisted blade portion are the same in blade angle, the mold for impeller outlet and the moving die are in a single piece, and the hub rim part and the blades are formed in a single piece at the same molding process.
6. The manufacturing method according to claim 1, characterized in that, a shroud line and a hub line of the rest portion of each of the blades other than the twisted blade portion are different in blade angle, the shroud rim part and the hub rim part are parallel to each other, and the mold for impeller outlet only provides a single radially mold slide in a space between any two of the blades adjacent to each other.
7. A die-formed 3-dimensional plastic impeller of a centrifugal pump, characterized in that, the 3-dimensional plastic impeller comprises: a shroud, a hub, and a plurality of blades, together form flow channel in the impeller for working fluid, the shroud and the hub are configured to restrict a flow path of the working fluid, the hub is configured to transmit torque to the blades, each of the blades has a 3-dimensional twisted shape configured to improve pump efficiency, characterized in that: each of the blades comprises a front portion, a rear portion connected to the front portion, a shroud line connected to the shroud, and a hub line connected to the hub, wherein the shroud line comprises a first shroud line and a second shroud line, the hub line comprises a first hub line and a second hub line, the first shroud line and the first hub line are located on the front portion, the second shroud line and the second hub line are located on the rear portion, and the first shroud line and the first hub line are different in blade angle; the hub comprises a hub rim part and an inner hub, the hub rim part has a hub hole, and the hub rim part has a power transmission seat configured to transmit torque to the blades; the shroud comprises a shroud rim part and an inner shroud, the shroud rim part has a shroud hole; the front portion of each of the blades is located between the hub hole of the hub rim part and the shroud hole of the shroud rim part; the rear portions of the blades and the hub rim part are formed in a single piece at the same molding process, and the rear portions of the blades are connected to the shroud rim part; and the inner shroud and the inner hub are respectively installed in the shroud hole and the hub hole so as to be combined with the front portions of the blades.
8. The 3-dimensional plastic impeller according to claim 7, characterized in that, the shroud is configured for a wear ring to be installed thereon.
9. The 3-dimensional plastic impeller according to claim 7, characterized in that, the second shroud line and the second hub line of each of the blades are the same in blade angle.
10. The 3-dimensional plastic impeller according to claim 7, characterized in that, the shroud rim part and the inner shroud are formed in a single piece.
11. An impeller of centrifugal pump, characterized in that, the impeller comprises: a hub comprising a hub rim part and an inner hub, wherein the hub rim part has a hub hole; and a plurality of blades being arranged along the hub rim part, wherein the blades each have a twisted blade portion located at the hub hole of the hub rim part and formed above a central portion; wherein the hub rim part and the blades are formed in a single piece at the same molding process, the twisted blade portions and the hub rim part do not overlap with each other, and the hub hole of the hub rim part and the inner hub are disposed by heat welding or melting rods, thereby together forming the impeller.
12. The impeller according to claim 11, characterized in that, each of the blades comprises a front portion and a rear portion connected to each other, the front portion is the twisted blade portion and connected to the hub rim part via the rear portion, each of the front portions has a first shroud line and a first hub line, and the first shroud line and the first hub line are different in blade angle.
13. The impeller according to claim 12, characterized in that, the inner hub is connected to the hub rim part and the first hub line of each of the blades.
14. The impeller according to claim 11, characterized in that, further comprises a reinforcing metal embedded in the hub rim part and the blades.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1A is a side cross-sectional view of a conventional plastic impeller having 2-dimensional blades.
[0067] FIG. 1B is a top view of the plastic impeller in FIG. 1A.
[0068] FIG. 1C shows the grid-lines of the 2-dimensional blade in FIG. 1A.
[0069] FIG. 1D is a perspective exploded view of the 2-dimensional blade in FIG. 1A.
[0070] FIG. 2A is a side cross-sectional view of a conventional plastic impeller having 3-dimensional blades but having no shroud.
[0071] FIG. 2B is a top view of the plastic impeller in FIG. 2A.
[0072] FIG. 2C shows the grid-lines of the 3-dimensional blade in FIG. 2A.
[0073] FIG. 2D is a schematic view of the 3-dimensional blade in FIG. 2A showing a plurality of curved sections thereof.
[0074] FIG. 3A is a side cross-sectional view of a conventional plastic impeller having a 2.5-dimensional blade surface but having no shroud.
[0075] FIG. 3B is a top view of the plastic impeller in FIG. 3A.
[0076] FIG. 3C shows the grid-lines of the 3-dimensional blade in FIG. 3A.
[0077] FIG. 4A is a side cross-sectional view of a plastic impeller according to a first embodiment of the disclosure.
[0078] FIG. 4B is a top view of the plastic impeller in FIG. 4A.
[0079] FIG. 4C shows a grid-lines of the blade in FIG. 4A.
[0080] FIG. 4D illustrates an exploded view of the plastic impeller of the first embodiment of the disclosure and the molds for manufacturing the same.
[0081] FIG. 4E is a partial enlarged side cross-sectional view of the plastic impeller of the first embodiment of the disclosure.
[0082] FIG. 4F is a side cross-sectional view of a variant of the plastic impeller of the first embodiment of the disclosure.
[0083] FIG. 4G is a partial enlarged side cross-sectional view of the variant of the plastic impeller of the first embodiment of the disclosure.
[0084] FIG. 5 is an assembly cross-sectional view of the plastic impeller of the first embodiment of the disclosure.
[0085] FIGS. 6A-6B illustrate exploded views of the plastic impeller of the first embodiment of the disclosure, taken from different angles.
[0086] FIGS. 7A-7B illustrate exploded views of the plastic impeller of the first embodiment of the disclosure, taken from different angles.
[0087] FIG. 8A is a side cross-sectional view of a plastic impeller according to a second embodiment of the disclosure.
[0088] FIG. 8B is a top view of the plastic impeller in FIG. 8A.
[0089] FIG. 8C shows a grid-lines of the blade in FIG. 8A.
[0090] FIG. 8D illustrates an exploded view of the plastic impeller of the second embodiment of the disclosure and the molds for manufacturing the same FIG. 9 is an assembly cross-sectional view of the plastic impeller of the second embodiment of the disclosure.
[0091] FIG. 10A is a side cross-sectional view of a plastic impeller according to a third embodiment of the disclosure.
[0092] FIG. 10B is a top view of the plastic impeller in FIG. 10A.
[0093] FIG. 10C shows a grid-lines of the blade in FIG. 10A.
[0094] FIG. 10D illustrates an exploded view of the plastic impeller of the third embodiment of the disclosure and the molds for manufacturing the same.
[0095] FIG. 11 is an assembly cross-sectional view of the plastic impeller of the third embodiment of the disclosure.
[0096] FIG. 12 is an assembly cross-sectional view of a plastic impeller according to a fourth embodiment of the disclosure.
[0097] wherein, the labels in the drawings: [0098] 5 impeller [0099] 7 rotor [0100] 8 wear ring [0101] 11, 51 shroud [0102] 12, 22, 52 hub [0103] 13, 23, 33, 53 blade [0104] 54 suction [0105] 55 reinforcing metal [0106] 131, 231, 331, 531 meridional width [0107] 132, 232, 332, 532 leading edge [0108] 134, 234, 334, 534 shroud line [0109] 135, 235, 335, 535 hub line [0110] 136, 236, 336, 536 trailing edge [0111] 137, 237, 337, 537 sector width [0112] 138, 238, 338, 538 mean line [0113] 233, 333 twisted blade portion [0114] 239, 339 blade surface [0115] 239a curved line element [0116] 339b straight line element [0117] 511 shroud rim part [0118] 512 inner shroud [0119] 512a wear ring seat [0120] 512b welding segment [0121] 512c melting hole [0122] 521 hub rim part [0123] 521a power transmission seat [0124] 522 inner hub [0125] 522a melting hole [0126] 522b welding segment [0127] 530a front portion [0128] 530b rear portion [0129] 534a welding segment [0130] 534b melting rod [0131] 535a welding segment [0132] 535b melting rod [0133] 5110 shroud hole [0134] 121, 221, 321, 5111 inner surface [0135] 5210 hub hole [0136] 111, 5211 inner surface [0137] 5341 first shroud line [0138] 5342 second shroud line [0139] 5351 first hub line [0140] 5352 second hub line [0141] B11, B21, B31, B51 inlet width [0142] B12, B22, B32, B52 outlet width [0143] ![custom-character]()
meridional coordinate [0144] M1 mold for twisted blade [0145] M11 fixed die [0146] M12 moving die [0147] M2 mold for impeller outlet [0148] M21 hub slide [0149] M211 hub slide surface [0150] M22 shroud slide [0151] M221 shroud slide surface [0152] β blade angle [0153] β.sub.2 outlet blade angle
DETAILED DESCRIPTION
[0154] The detailed features and advantages of the disclosure are set forth in the detailed description below, which are for those skilled in the art to understand the technical contents of the disclosure, and in accordance with the disclosure, the scope of the claims, and the accompanying drawings, any person skilled in the art can easily understand the purpose and advantages of the disclosure. The following embodiments further elaborate on the disclosure but do not limit the scope of the disclosure by any point of view.
[0155] In addition, the disclosure of the disclosure will be disclosed in the following figures. For clarity, many practical details will be explained in the following descriptions. However, it should be understood that these practical details are not used to limit the disclosure.
[0156] Moreover, some existing conventional structures and components may be shown in a simple schematic manner for the purpose of simple illustration. In addition, some of the features in the drawings of the disclosure may be slightly enlarged or changed in proportion or size for the purpose of understanding and viewing the technical features of the disclosure, but this is not intended to limit the disclosure. The actual size and specifications of the products manufactured in accordance with the disclosure of the disclosure may be adjusted according to the requirements, the characteristics of the product itself, and the contents of the disclosure as disclosed below.
First Embodiment
[0157] Firstly, referring to FIGS. 4A-4C, and FIG. 5, FIG. 4A is a side cross-sectional view of an impeller 5 according to the first embodiment of the disclosure, FIG. 4B is a top view of the impeller 5 in FIG. 4A, FIG. 4C shows a grid-lines of the blade 53 in FIG. 4A, and FIG. 5 is an assembly cross-sectional view of the impeller 5 of the first embodiment of the disclosure. This embodiment provides a plastic impeller 5 for a centrifugal pump having 3-dimensional flow channels.
[0158] In this embodiment, the impeller 5 includes a plurality of blades 53, a hub rim part 521, an inner hub (rear inner plate) 522, a shroud rim part 511, and an inner shroud (front inner plate) 512. As shown in FIG. 5, the shroud rim part 511 and the inner shroud 512 together from a shroud 51, and the hub rim part 521 and the inner hub 522 together from a hub 52, In addition, as shown in FIG. 4A or FIG. 4F, the shroud rim part 511 has an inner surface 5111, the surface element of the inner surface 5111 on the r_z plane is a curved line; the hub rim part 521 has an inner surface 5211, the surface element of the inner surface 5211 on the r_z plane is a straight line parallel to the r-axis so as to form a flat surface; in other words, the inner surface 5211 is a 2-dimensional annular flat surface.
[0159] Further, as shown in FIG. 4A or FIG. 4B, the hub rim part 521 has a hub hole 5210, the shroud rim part 511 has a shroud hole 5110, each blade 53 is at least partially located between the shroud hole 5110 of the shroud rim part 511 and the hub hole 5210 of the hub rim part 521.
[0160] In detail, regarding the blade 53, on the r_z plane (meridional plane), the blade 53 has a leading edge 532 near the suction 54, the blade 53 has a shroud line 534 at a side thereof connected to the shroud rim part 511, the blade 53 has a hub line 535 at a side thereof connected to the hub rim part 521, the blade 53 has a trailing edge 536 at a side thereof located furthest away from the suction 54, and there is a mean line 538 between the shroud line 534 and the hub line 535. In more detail, in this embodiment, the blade 53 includes a front portion 530a and a rear portion 530b connected to each other, the front portion 530a is the portion of the blade 53 located relatively closer to the leading edge 532, and the rear portion 530b is the portion of the blade 53 located relatively closer to the trailing edge 536; that is, the front portion 530a is the portion of the blade 53 located relatively closer to the suction 54, and the rear portion 530b is the portion of the blade 53 located relatively away from the suction 54. Also, in this embodiment or some other embodiments, the shape of the front portion 530a is much more twisted than the rear portion 530b, thus, the front portion 530a is the 3-dimensional twisted portion of the blade 53 and can also be called twisted blade portion. In addition, the front portion 530a of the blade 53 is located between the shroud hole 5110 of the shroud rim part 511 and the hub hole 5210 of the hub rim part 521, in other words, the twisted blade portion of the blade 53 is located between the shroud hole 5110 of the shroud rim part 511 and the hub hole 5210 of the hub rim part 521. In addition, the front portion 530a is connected to the hub rim part 521 and the shroud rim part 511 via the rear portion 530b.
[0161] In addition, the meridional width 531 of the blade 53 gradually decreases from the widest suction width B51 of the blade 53 to the narrowest outlet width B52 of the blade 53. In addition, in FIG. 4B, viewing from the angle on the r_θ plane, two adjacent blades 53 have a sector width 537 therebetween, the leading edge 532, the shroud line 534, and the hub line 535 do not overlap with one another. Particularly, in FIGS. 4A and 4B, regarding the front portion 530a and the rear portion 530b of the blade 53, the shroud line 534 of the blade 53 includes a first shroud line 5341 and a second shroud line 5342, the hub line 535 of the blade 53 includes a first hub line 5351 and a second hub line 5352; in other words, the first shroud line 5341 and the first hub line 5351 respectively are the portions of the shroud line 534 and the hub line 535 on the front portion 530a, and the second shroud line 5342 and the second hub line 5352 respectively are the portions of the shroud line 534 and the hub line 535 on the rear portion 530b. In this embodiment, on the shroud line 534, only the second shroud line 5342 is directly connected to the shroud rim part 511; on the hub line 535, only the second hub line 5352 is directly connected to the hub rim part 521.
[0162] In this embodiment and other embodiments, the blade 53 is in a twisted shape, thus the second shroud line 5342 and the second hub line 5352 of the rear portion 530b of the blade 53 do not overlap with each other on the grid-lines of blade 53 (e.g., shown in FIG. 4C), and the first shroud line 5341 and the first hub line 5351 of the front portion 530a of the blade 53 are different in blade angle, thus the first shroud line 5341 and the first hub line 5351 do not overlap with each other on the grid-lines of the blade 53 (e.g., shown in FIG. 4C). The non-overlapping between the first shroud line 5341 and the first hub line 5351 on the front portion 530a can be seen more obvious on the impeller 5 viewing from the grid-lines, thus the front portion 530a of the blade 53 has a more drastic geometry change compared to the rear portion 530b.
[0163] Specifically, it would be clearer viewing from the grid-lines of the blade 53 in FIG. 4C, the outlet blade angles β.sub.2 are the same at the outlet, but closer to the suction 54 (i.e., closer to the axis of the impeller 5), the shroud line 534 and the hub line 535 have a greater difference in the blade angle β, meaning that the twist degree of the blade increases, this particularly occurs at the 3-dimensional twisted front portion 530a near the leading edge 532 of the blade 53, thus the mold slides that are removed in a radial manner cannot be used to form the front portion 530a of this embodiment, the contents will be illustrated in the following paragraphs.
[0164] Further, referring to FIG. 4D, an exploded view of the impeller 5 of the first embodiment of the disclosure and the molds for manufacturing the same is provided. In this embodiment and other embodiments, the molds for forming the impeller 5 within a single process can be divided into two units: a mold for twisted blade M1 and a mold for impeller outlet M2 shown in FIG. 4D. The mold for twisted blade M1 is configured to form the highly twisted front portions 530a (i.e., the twisted blade portions) between the hub hole 5210 of the hub rim part 521 and the shroud hole 5110 of the shroud rim part 511. In detail, the mold for twisted blade M1 includes, for example, a fixed die M11 and a moving die M12, the cooperation of the fixed die M11 and the moving die M12 is able to form the front portions 530a of these blades 53, since the shroud line 534 and the hub line 535 of the blade 53 at the front portion 530a have a greater difference in blade angle (i.e., the shroud line 534 and the hub line 535 of the blade 53 at the front portion 530a have a larger degree of non-overlapping on the grid-lines of the blade), thus the demolding of the fixed die M11 and the moving die M12 of the mold for twisted blade M1 is to axially remove the fixed die M11 and the moving die M12 respectively from the hub hole 5210 of the hub rim part 521 and the shroud hole 5110 of the shroud rim part 511 in opposite directions. Since the front portion 530a (i.e., the twisted blade portion) of each blade 53 is located between the shroud hole 5110 of the shroud rim part 511 and the hub hole 5210 of the hub rim part 521, axially removing the fixed die M11 and the moving die M12 along two opposite directions will not interfere with the blades 53, the shroud rim part 511, and the hub rim part 521. Herein, note that the disclosure is not limited to the positions, configurations, and features of the fixed die M11 and the moving die M12 shown in the drawings; for example, in some other embodiments, the positions of the fixed die M11 and the moving die M12 and features thereon can be switched.
[0165] In addition, since the shroud line 534 and the hub line 535 of the blade 53 on the rear portion 530b has a smaller difference in blade angle (i.e., on the grid-lines of the blade, the shroud line 534 and the hub line 535 of the blade 53 on the rear portion 530b have a lesser degree of non-overlapping), even in some other embodiments, the shroud line 534 and the hub line 535 of the blade 53 on the rear portion 530b may overlap with each other viewing from the grid-lines of the blade. As such, the mold for impeller outlet M2 may have a plurality of radially slidable mold slides or mold slide groups for integrally forming the rest portion (e.g., rear portion 530b) of the blade 53 other than the front portion 530a (i.e., the twisted blade portion).
[0166] As shown in FIG. 4D and FIG. 4E, specifically, in this embodiment, the mold for impeller outlet M2 may include plural groups of mold slide sets respectively configured to form the portions of the flow channels near outlet (i.e., the space between the rear portions 530b of the blades 53, the shroud rim part 511, and the hub rim part 521), each mold slide set may include a hub slide M21 and a shroud slide M22, at least part of the hub slide M21 and at least part of the shroud slide M22 can be cooperated with each other to form the inner surface 5211 of the hub rim part 521, the inner surface 5111 of the shroud rim part 511, and the rear portions 530b of the blades 53, wherein the hub slide M21 has a hub slide surface M211 configured to form the inner surface 5211 of the hub rim part 521, and the shroud slide M22 has a shroud slide surface M221 configured to form the inner surface 5111 of the shroud rim part 511. In this embodiment, the surface element of the hub slide surface M211 of the hub slide M21 is a straight line so as to form a flat surface, thus, the inner surface 5211 of the hub rim part 521 can be formed to be a flat surface having a surface element being a straight line. The surface element of the shroud slide surface M221 of the shroud slide M22 is a curved line, thus the shroud slide surface M221 is a convex conical surface; in such a case, the inner surface 5111 of the shroud rim part 511 can be formed to be a concave conical surface having a surface element being a curved line. On the other hand, since the impeller 5 requires the surface element of the inner surface 5111 of the shroud rim part 511, being a curved line, and the surface element of the inner surface 5211 of the hub rim part 521, being a straight line, the aforementioned hub slide M21 and shroud slide M22 are required. According to this requirement, the hub slide M21 and the shroud slide M22 are removed one after another. Specifically, after the blades 53, the shroud rim part 511, and the hub rim part 521 had been formed, the hub slide M21 is first removed in radial direction, and then the space that was occupied by the hub slide M21 becomes available for the removal of the shroud slide M22 so that the shroud slide M22 can be easily removed without interfering with the rear portions 530b of the blades 53, the shroud rim part 511, and the hub rim part 521.
[0167] However, the geometrical shapes of the hub slide M21 and the shroud slide M22 can be modified according to actual requirements, and the disclosure is not limited thereto. For example, as shown in FIG. 4F and FIG. 4G, in a variant of the previous embodiment, the impeller 5 is required to have the surface element of the inner surface 5111 of the shroud rim part 511 to be a straight line and the surface element of the inner surface 5211 of the hub rim part 521 to be a curved line, correspondingly, the hub slide surface M211 of the hub slide M21 for forming the inner surface 5211 of the hub rim part 521 has a surface element which is a curved line, such that the inner surface 5211 of the hub rim part 521 can be formed to be a concave conical surface having a surface element of curved line; and the shroud slide surface M221 of the shroud slide M22 for forming the inner surface 5111 of the shroud rim part 511 has a surface element which is a straight line, such that the inner surface 5111 of the shroud rim part 511 can be formed to be a flat surface having a surface element of straight line. Similarly, the hub slide M21 and the shroud slide M22 are removed one after another. Specifically, after the blades 53 had formed, the shroud slide M22 is firstly removed in radial direction, and then the space that was occupied by the shroud slide M22 becomes available for the removal of the hub slide M21 so that the hub slide M21 can be easily removed without interfering with portions that had formed in the previous process, such as the rear portion 530b of the blades 53, the shroud rim part 511, and the hub rim part 521. In addition, note that the geometric configurations or the mating surfaces of the hub slide and the shroud slide can be modified according to actual requirements, and the disclosure is not limited thereto.
[0168] Further, referring to FIG. 5, the impeller 5 is assembled to a rotor 7. The impeller 5 includes the shroud 51, the hub 52 and the blades 53. As discussed above, the shroud 51 is formed by the aforementioned shroud rim part 511 and inner shroud 512. Referring to FIG. 4A and the FIG. 5, the inner shroud 512 is at the shroud hole 5110 of the shroud rim part 511 and can be assembled to the shroud rim part 511 and the blades 53 by heat welding, ultrasonic welding or other suitable ways. In addition, a wear ring seat 512a is disposed on the inner shroud 512 and is configured for the installation of a wear ring 8. The hub 52 is formed by the aforementioned hub rim part 521 and inner hub 522. Referring to FIG. 4A and FIG. 5, the inner hub 522 is located at the hub hole 5210 of the hub rim part 521 and can be assembled to the hub rim part 521 and the blades 53 by heat welding, ultrasonic welding or other suitable ways. In addition, a power transmission seat 521a is disposed on the hub rim part 521 and is configured for being installed to the rotor 7.
[0169] The inner shroud 512 and the inner hub 522 in FIG. 5 can be additionally produced by using simple molds, the inner shroud 512 and the inner hub 522 are respectively connected to the first shroud line 5341 and the first hub line 5351 of each blade 53 so as to be assembled to the shroud rim part 511, the hub rim part 521 and the blades 53 and thereby together forming a complete 3-dimensional plastic impeller. For example, FIGS. 6A-6B illustrate exploded views of the impeller 5 of the first embodiment of the disclosure, taken from different angles, the welding segment 512b of the inner shroud 512 can be joined to the welding segments 534a of the blades 53 by heat welding, ultrasonic welding or other suitable ways; in a similar manner, the welding segment 522b of the inner hub 522 can be joined to the welding segments 535a of the blades 53 by heat welding, ultrasonic welding or other suitable ways. Alternatively, FIG. 7A-7B also illustrate exploded views of the impeller 5 of the first embodiment of the disclosure, taken from different angles, the inner shroud 512 may have melting holes 512c for the melting rods 534b to be inserted therein, the melting rods 534b can be heated to be joined with the melting holes 512c. Similarly, the inner hub 522 may have melting holes 522a for the melting rods 535b of the blades 53 to be inserted therein, the melting rods 535b can be heated to be joined with the melting holes 522a. Accordingly, the inner shroud 512 and the inner hub 522 are not produced by the molding process of forming the shroud rim part 511, the hub rim part 521, and the blades 53 into a single piece.
[0170] Referring to FIG. 5, the power of the pump is transmitted via the power transmission seat 521a and the hub rim part 521 and then to the blades 53, since these three portions are formed in a single piece at the same molding process; that is, the blades 53, the hub rim part 521, and the power transmission seat 521a thereof have no seams, joints, or junction caused by any other processes among them. Therefore, there are no seams or structural discontinuity among the blades 53, the hub rim part 521, and the power transmission seat 521a, thus the single piece formed by these portions has high structural strength. As such, the hub rim part 521 is able to be employed to receive the main loading or power transmission of the pump, helping to expand the application range of the pump. In addition, although the inner shroud 512 and the inner hub 522 are formed by using simple molds and then assembled to other parts to form a complete impeller by heat welding, ultrasonic welding or other suitable ways, the inner shroud 512 and the inner hub 522 are merely employed to restrict the fluid in the range of the impeller 5 but not employed to directly receive the main load or power transmission of the pump, thus the way of forming the inner shroud 512 and the inner hub 522 does not affect the structural strength of the pump. As a result, the impeller 5 of this embodiment is able to operate at various applications under conditions, such as high temperature (e.g., 200° C.) and high load.
Second Embodiment
[0171] Referring to FIGS. 8A-8C and FIG. 9, FIG. 8A is a side cross-sectional view of an impeller 5 according to a second embodiment of the disclosure, FIG. 8B is a top view of the impeller 5 in FIG. 8A, FIG. 8C shows a grid-lines of the blade 53 in FIG. 8A, FIG. 9 is an assembly cross-sectional view of the impeller 5 of the second embodiment of the disclosure. As shown in the figures, the main differences between this embodiment and the previous embodiments are: the meridional width 531 of the blade 53 of the second embodiment decreases in a direction pointing from the inlet width B51 to the portion between the front portion 530a and the rear portion 530b, the shroud rim part 511 has an inner surface 5111 whose surface element on the r_z plane is a straight line parallel to the r-axis and thus forming a flat surface, in other words, the inner surface 5111 is a 2-dimensional annular flat surface; the hub rim part 521 has an inner surface 5211 whose surface element on the r_z plane is a straight line parallel to the r-axis and thus forming a flat surface, in other words, the inner surface 5211 is a 2-dimensional annular flat surface. That is, the inner surface 5111 and the inner surface 5211 are parallel to each other, thus the meridional width 531 does not change in a direction pointing from to the portion between the front portion 530a and the rear portion 530b toward the outlet width B52, and the second shroud line 5342 and the second hub line 5352 are substantially parallel to each other on the r_z plane. That is, in this embodiment, the meridional width 531 of the front portion 530a of the blade 53 decreases in a direction pointing from the inlet width B51 toward the outlet width B52 along the mean line 538, but the meridional width 531 of the rear portion 530b of the blade 53 does not change along the mean line 538. As shown in FIG. 8B, the leading edge 532, the shroud line 534, and the hub line 535 do not overlap with each other at the front portion 530a of the blade 53, and the shroud line 534 and the hub line 535 do not overlap with each other at the rear portion 530b of the blade 53.
[0172] In addition, on the grid-lines of the blade 53 shown in FIG. 8C, the outlet blade angles are the same, in the range from the portion between the front portion 530a and the rear portion 530b to the trailing edge 536, the second shroud line 5342 and the second hub line 5352 have a difference in blade angle β within 10 degrees. Therefore, the mold for the impeller outlet in this embodiment can be modified to be a single mold slide that can be removed in the radial direction.
[0173] In detail, further referring to FIG. 8D, an exploded view of the impeller of this embodiment and the molds for manufacturing the same is illustrated. In this embodiment, the shroud rim part 511 and the hub rim part 521 are substantially parallel to each other on the r_z plane (meridional plane), that is, the inner surfaces of the shroud rim part 511 and the hub rim part 521 facing towards each other are parallel to each other, thus the space between the shroud rim part 511 and the hub rim part 521 does not increase in width from the outside towards the inside. Therefore, comparing to the aforementioned FIG. 4D, the mold for impeller outlet M2 of this embodiment may be a single mold slide with a uniform thickness and capable of being radially removed, and the hub slide surface M211 and the shroud slide surface M221 of the single mold slide for forming the inner surface 5211 of the hub rim part 521 and the inner surface 5111 of the shroud rim part 511 have surface elements both being a straight line. By this configuration, the mold for impeller outlet M2 is able to be removed in the radial direction on the r_z plane (meridional plane). Also, the shroud rim part 511 and the hub rim part 521 are parallel viewing from the r_z plane (meridional plane), the sector width 537 increases as the radius increases on the r_θ plane, thus the demolding of the mold for impeller outlet does not lead to interference.
Third Embodiment
[0174] Referring to FIGS. 10A-10C and FIG. 11, FIG. 10A is a side cross-sectional view of an impeller 5 according to a third embodiment of the disclosure, FIG. 10B is a top view of the impeller 5 in FIG. 10A, FIG. 10C shows a grid-lines of the blade 53 in FIG. 10A, FIG. 11 is an assembly cross-sectional view of the impeller 5 of the third embodiment of the disclosure.
[0175] The main differences between this embodiment and the previous embodiments are: the third embodiment is for the impeller 5 of pump with a lower flow rate, higher head, and lower specific speed, wherein the impeller 5 may not have the aforementioned shroud rim part 511, and the blade 53 only requires 3-dimensional twisted geometry at the front portion 530a, and the rear portion 530b of the blade 53 may have a 2-dimensional blade geometry. Specifically, the first shroud line 5341 and the first hub line 5351 are different in blade angle (i.e., the first shroud line 5341 and the first hub line 5351 do not overlap with each other on the grid-lines of the blade), but the second shroud line 5342 and the second hub line 5352 may be the same in blade angle (i.e., the second shroud line 5342 and the second hub line 5352 may overlap with each other on the grid-lines of the blade). The hub rim part 521 has an inner surface 5211, the surface element of the inner surface 5211 is a straight line parallel to r axis on the r_z plane.
[0176] In addition, on the grid-lines of the blade in FIG. 10C, the rear portion 530b of the blade 53, the shroud line 534, the mean line 538, and the hub line 535 are the same in blade angle β.
[0177] Therefore, in this embodiment, the mold for the impeller outlet for forming the rear portion 530b of the blade 53 has no need to be radially removed but can be axially removed similar to the process in removing the mold for twisted blade for forming the front portion 530a of the blade 53. In detail, further referring to FIG. 10D, FIG. 10D illustrates an exploded view of the impeller of this embodiment and the molds for manufacturing the same. In this embodiment, since the impeller 5 does not have the shroud rim part 511, the side of the blades 53 away from the hub rim part 521 is not covered, and the rear portion 530b of the blade 53 is a 2-dimensional blade geometry, thus, the moving die M12 of the mold for twisted blade M1 for forming the twisted front portion 530a (i.e., the twisted blade portion) can be integrally formed with the mold for impeller outlet M2 for forming the rear portion 530b, and they can be axially removed along a direction away from the hub rim part 521 without interfering with the blades 53 during the removal.
[0178] Regarding the shroud 51, the shroud rim part 511 and the inner shroud 512 can be formed of a single piece by using simple molds, and then the shroud 51 can be connected to the blades 53 by heat welding, ultrasonic welding or other suitable ways so as to form a complete impeller 5.
Fourth Embodiment
[0179] Referring to FIG. 12, FIG. 12 is an assembly cross-sectional view of an impeller 5 according to a fourth embodiment of the disclosure. The main differences between this embodiment and the previous embodiments are: reinforcing metal 55 is embedded in the blades 53, the hub rim part 521, and the shroud rim part 511 of the impeller 5, the reinforcing metal 55 is configured to improve the rigidity of the overall structure, allowing the plastic impeller to work stably at high temperature (200° C.) and high load without failure. Note that, in some other embodiments, the shroud rim part 511 may not contain the reinforcing metal 55; that is, in such a case, in the impeller 5, the reinforcing metal 55 is only embedded in the blades 53 and the hub rim part 521.
[0180] Accordingly, the manufacturing method of the 3-dimensional plastic impeller for centrifugal pump and the impeller manufactured thereby as disclosed in the previous embodiments of the disclosure at least can achieve the following effects: 1. Each part can be produced using mold and can be automatically demolded, having production value; 2. The twisted blade portions can be formed by using a removable and separable fixed die and moving die, and the 3-dimensional twisted blade geometry helps improve pump performance; 3. The blades and the hub rim part are formed in a single piece at the same molding process and thus having a higher structural strength, the hub rim part directly transmits torque to the blades, which helps the impeller to operate at high working temperature (e.g., approximately 200° C.) or high load without being damaged.
