HK1187391B - Non-metallic vertical turbine pump - Google Patents

Description

Non-metal vertical turbine pump

Cross Reference to Related Applications

This application claims the benefit of U.S. patent application serial No. 61/374,452, filed on 8/17/2010, the entire disclosure of which is incorporated herein by reference.

Background

Conventional fluid (e.g., water) pumps can be oriented in a vertical or horizontal position based on the direction of the shaft. Vertical pumps, units having a vertical shaft configuration, can be further classified as dry or wet well configurations, and subsequently as screw, propeller or vertical turbine pumps. A vertical turbine pump includes a motor mounted on some type of base or motor support attached to an upper surface of a motor attachment member. The pump shaft can be directly attached or coupled to the motor and extend downward toward the casing and the impeller via a cylindrical support or vertical tube member. Depending on the vertical pump design, the casing may be of a spiral (typically single stage with a vortex diffuser) or vaned (typically multi-stage) diffuser configuration. The impeller includes a plurality of impeller blades that rotate with the motor and shaft and increase the exit velocity of the fluid. The impeller also creates a pressure differential while pumping water from the inlet or suction end to the outlet or discharge end. The impeller of a screw-type pump typically includes a radial impeller blade configuration that turns the fluid 90 degrees within the casing to direct the pumped fluid to a casing discharge end perpendicular to the casing suction end. The impeller of a vertical turbine pump typically includes a mixed flow impeller vane configuration that turns the fluid more than 90 degrees into a vaned diffuser housing that continues to turn the fluid until it is discharged 180 degrees from the inlet. The impeller of a propeller pump (typically a single stage) does not change the direction of fluid flow and the fluid exits the impeller and housing 180 degrees from the inlet. Vertical pumps are used in several applications. For example, in agricultural irrigation, water is pumped up from the ground water level. In addition, water can be pumped from rivers or lakes for use in power plants. Additionally, the pump can be used to pump water in reverse osmosis applications.

For ease of manufacturability, impellers and vertical turbine pumps have been made of metallic materials. Unfortunately, the associated corrosiveness of metal components affects the life of these pumps. Therefore, when a vertical pump is used and corrosion is an issue, screw pumps that have been made of corrosion resistant non-metallic materials are utilized.

Impeller and vertical turbine pumps comprise a vane housing comprising a plurality of diffuser vanes arranged in the housing at a position downstream of the impeller. Similar to a spiral, the diffuser vanes increase the flow area in the direction of fluid flow, thus reducing the velocity of the fluid flowing through the housing and increasing the head pressure. Furthermore, the impeller blades of a vertical turbine pump are twisted, defining a combined axial and radial flow characteristic. Due to the complex geometry of impeller and vertical turbine pump components, conventional impeller and vertical turbine pumps are not currently made from fiberglass reinforced molded non-metallic materials because of the inability to provide sufficient molds to make these non-metallic parts. In particular, since the diffuser has two or more passages, the diffuser is not formed from a single piece made of uniform material.

For example, schmidt pump valve companies have attempted to manufacture vertical turbine pumps made from a single block forged from non-metallic corrosion resistant materials. However, complex pump components such as impellers and diffusers are machined from these single block forgings without fiberglass reinforcement using multi-axis tooling that limits the design and size of these components due to "line of sight" machining limitations. In addition, conventional vertical turbine pumps having certain non-metallic components also include certain wet components made of metal, such as a discharge elbow.

Accordingly, what is desired is an improved non-metallic vertical turbine pump made of corrosion resistant fiberglass reinforced resin having parts that can be molded into uniform solid shapes and that include reduced wet metal parts.

Disclosure of Invention

According to one embodiment, a vertical turbine pump may include: a motor and a drive shaft coupled to the motor for rotation; a housing with a mixed flow diffuser, the diffuser including a diffuser hub and diffuser vanes projecting outwardly from the diffuser hub; and a mixed flow impeller configured to be rotatably fitted inside the casing, the mixed flow impeller having an impeller hub, impeller blades extending from the impeller hub, and front and rear shrouds connected to opposite ends of the impeller blades. At least one of the mixed flow impeller and the mixed flow diffuser may be made of a non-metallic material and be a single uniform component. The non-metallic material can be reinforced by glass fibers; and has improved corrosion resistance, although capable of exhibiting similar strength to metal parts. The pump may include: a discharge head comprising a discharge cylinder, an elbow, and a stuffing box holder extending into the elbow at a joint; and a non-metallic material covering the joint. The pump may also have a metal mount supporting the motor and disposed between the elbow and the discharge cylinder, and at least one insert at an interface between the elbow and the cylinder.

According to another embodiment, a non-metallic vertical turbine pump can be manufactured using a method of molding at least a portion of the pump, the method including providing a core, making a cut in the core, introducing a non-metallic composite material into the cut and around opposing ends of the core, and removing the core. The manufacturing step may include machining a cut-out in the core. The composite material may be a glass fiber reinforced resin, wherein the glass fibers are oriented to provide a desired level of internal strength and bonding, and the resin comprises a vinyl ester resin or an epoxy resin. The core may have a lower melting temperature than the composite material. The core may also be a wax-like body formed by introducing wax into the silicone rubber mold.

Drawings

The foregoing summary, as well as the following detailed description of various embodiments of the present application, will be better understood when read in conjunction with the appended drawings. Reference is made to the accompanying drawings for the purpose of illustrating various embodiments of the disclosure. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:

fig. 1A is a schematic perspective view of a vertical turbine pump constructed in accordance with one embodiment, including a proximal end portion including a motor and a drive shaft attached to an intermediate portion including an exhaust tube connected to the motor by a motor attachment member, and a distal end portion attached to the intermediate portion via the exhaust tube, the distal end portion including a housing holding an impeller, a diffuser, and a suction horn;

fig. 1B is a schematic sectional elevational view of the vertical turbine pump shown in fig. 1A.

FIG. 2 is an enlarged cross-sectional partial perspective view of the proximal and intermediate portions of the vertical turbine pump shown in FIG. 1A, the discharge elbow of the vertical turbine pump shown in FIG. 1A;

FIG. 3A is a schematic cross-sectional perspective view of a portion of the distal end of the vertical turbine pump shown in FIG. 1A including a distal end portion and an exhaust tube;

FIG. 3B is a schematic cross-sectional elevational view of the distal portion and the distal end of the evacuation tube shown in FIG. 3A;

FIG. 4A is an enlarged schematic perspective view of a distal portion of the vertical turbine pump shown in FIG. 1A including a housing, an impeller, a diffuser and a suction horn;

FIG. 4B is a schematic cross-sectional elevation view of the housing, impeller, diffuser and suction horn shown in FIG. 4A;

FIG. 5A is an enlarged cross-sectional perspective view of the impeller shown in FIGS. 4A, 4B;

FIG. 5B is an enlarged cross-sectional perspective view of the housing and diffuser shown in FIGS. 4A, 4B;

FIG. 6A illustrates a vertical turbine pump according to an embodiment; and

fig. 6B shows a vertical turbine pump according to another embodiment.

FIG. 7 is a perspective view of a molded uniform impeller mounted to a drive shaft according to one embodiment;

FIG. 8A is a perspective view of a core configured to produce the molded uniform impeller shown in FIG. 7;

FIG. 8B is a schematic view showing glass fiber reinforced fibers introduced into and around the core shown in FIG. 8A;

FIG. 8C is a schematic view of a core and glass fibers disposed in a mold cavity;

FIG. 8D is a perspective view of the molded construction after resin is introduced and hardened inside the mold cavity;

FIG. 8E is a perspective view of the molded construction shown in FIG. 8D removed from the mold cavity;

FIG. 8F is a perspective view of the molded construction with the flashing removed;

fig. 9A to 9C are perspective views of the molded impeller with the core removed;

10A-10C are perspective views of a mold core configured for use in the manufacture of a diffuser;

FIG. 10D is a view of a mold core and fibers of glass fibers arranged in a mold cavity used in the manufacture of a diffuser;

FIG. 10E is a perspective view of the molded construction after resin is introduced and hardened inside the mold cavity used in the manufacture of the diffuser; and

fig. 11A-11C are perspective views of a non-metallic discharge elbow and stuffing box flange for manufacturing a vertical turbine pump.

Detailed Description

Referring to fig. 1A to 1B, the vertical turbo pump 20 is elongated substantially in a longitudinal direction L extending parallel to the L axis, and further extends in a lateral direction a parallel to the a axis and substantially perpendicular to the longitudinal direction L, and a lateral direction T extends parallel to the T axis and substantially perpendicular to the longitudinal direction L and the lateral direction a. It should be understood that, unless otherwise indicated, an axial direction can be referred to synonymously with the longitudinal direction L, and, unless otherwise indicated, a radial direction can be referred synonymously with a direction substantially perpendicular to the longitudinal direction L, such as the transverse direction a.

The vertical turbo pump 20 can include: a proximal portion 17, the proximal portion 17 being at an upper end defining a fluid discharge end; a distal portion 19, the distal portion 19 being at an opposite lower end spaced from the proximal portion 17 in the longitudinal direction L and defining a fluid inflow end; and an intermediate portion 18, the intermediate portion 18 being disposed between the proximal portion 17 and the distal portion 19. The proximal end portion 17 can include a motor 22 and a drive shaft 28 extending from the motor 22 and rotationally coupled to the motor 22. During operation of the pump 20, the motor 22 actuates the drive shaft 28 to rotate about the L-axis. As described below, the motor 22 and drive shaft 28 of the proximal section 17 can be connected to the intermediate section 18. The intermediate portion 18 can include a motor support 24, an attachment member 25, a driven shaft 29, and a discharge tube 32. The discharge tube 32 can include a cylindrical body 35 and an elbow 33 that is radially curved to define an outlet 36.

The motor support 24 and the attachment member 25 can be configured to attach to the discharge tube 32 and secure the motor 22 to the discharge tube 32 so as to hold the motor 22 in place over the discharge tube 32 during operation of the vertical turbine pump 20. The attachment member 25 can be configured to connect the motor support 24 to the discharge tube 32. In one embodiment, the intermediate portion 18 can include a mounting plate 26 that can be secured to the attachment member 25. The mounting plate 26 can be used to secure the vertical turbine pump 20 in a desired position.

Referring to fig. 1B and 2, the intermediate portion 18 can further include a coupling 23 that rotationally couples the drive shaft 28 of the proximal portion 17 to the driven shaft 29 such that rotation of the drive shaft 28 about the L-axis causes rotation of the driven shaft 29 about the L-axis during operation of the pump 20. The driven shaft 29 extends axially in the longitudinal direction L from the coupling 23 through the distal end portion 19 of the pump 20.

The elbow 33 can define an opening 58 that receives the driven shaft 29. As shown, the driven shaft 29 can pass through an opening 58 at the distal end of the coupling 23 at a joint 61 that fixedly connects the opening 58 of the elbow 33 to the stuffing box support 27. The stuffing box support 27 can extend proximally upward from the joint 61 about the driven shaft 29. The stuffing box support 27 can include a stuffing box 27 that houses a gasket or mechanical seal 41 against the driven shaft 29 to prevent fluid flowing through the elbow 33 from passing through the opening 58 and into the stuffing box 37. In one embodiment, the seal or mechanical seal 41 can be configured to allow some flow of fluid from the elbow 33 through the opening 58 to the bearing 44a, which provides lubricant to the bearing 44 a. In another embodiment, the stuffing box 37 can include an injection port 39, the injection port 39 configured to deliver lubricant to the bearing 44 a.

The upper portion of the attachment member 25 can have a proximal flange 81, the proximal flange 81 having a proximal surface 81a that mates with the distal surface 24b of the motor support 24. A radially inward portion of the proximal flange 81 can mate with a cross member 82 of the attachment member 25. The cross member 82 can extend downward in the longitudinal direction L to a fixing member 83 of the attachment member 25. Securing member 83 can extend inwardly from cross member 82 in a radial direction (which radial direction can be used interchangeably herein with the transverse direction) to define opening 56 disposed between distal end 33b of elbow 33 and proximal end 35a of cylinder 35. The vertical turbine pump 20 can include an insert 57, the insert 57 configured to fit within the opening 56 such that fluid flowing through the discharge tube 32 contacts the insert 57, and the insert 57 is prevented from making contact with the attachment member 25. Vertical turbine pump 20 can include one or more, such as a pair of, resilient O-rings 84a, 84b, which resilient O-rings 84a, 84b secure insert 57 between distal end 33b of elbow 33 and proximal end 35a of cylinder 35.

The cylindrical body 35 of the discharge tube 32 can extend distally from the attachment member 25 to the distal end portion 19 of the vertical turbine pump 20. As shown, the cylindrical body 35 can be a tubular member defining a bore 45 extending through the cylindrical body 35. The driven shaft 29 can be disposed within the bore 45 of the cylindrical body. The cylindrical body 35 can further include a bearing 44b that extends radially inward from the cylindrical body 35 to support the driven shaft 29. The proximal end 35a of the cylindrical body 35 can be coupled to the distal end 33b of the elbow so that, in operation, fluid flows from the distal portion 19 of the pump 20, through the cylindrical body 35 and the elbow 33 of the discharge tube 32, and out the outlet 36 of the elbow 33.

Referring to fig. 3A and 3B, the cylindrical body 35 defines a distal end 35B that is connectable to the distal portion 19 of the pump 20. The spacer 31 disposed at the upper end of the distal end portion 19 can be configured to mate with the distal end 35b of the cylinder 35. The distal portion 19 can further include a housing 38, the housing 38 having an upper end 38a secured to a lower end 31b of the spacer 31. In addition, distal portion 19 can include an inlet 40. The inlet 40 is configured to draw fluid into the distal portion 19 of the pump 20. In one embodiment, the inlet 40 can be in the form of a suction horn 42 secured to the lower end 38b of the housing 38. The inlet 40 can be angularly offset relative to the outlet 36. As shown in fig. 1B, the inlet 40 and the outlet 36 can be offset so that they are substantially perpendicular to each other.

Referring to fig. 3A and 3B, the suction horn 42 can include a bearing 44c that slidably supports the driven shaft 29 at the distal end 29B such that the bearing 44c remains stationary within the suction horn 42 as the driven shaft 29 rotates about the L-axis. The impeller 30, which can be configured to be rotatably fitted within the housing 38, is rotatably coupled to the driven shaft 29 so that the impeller 30 rotates together with the driven shaft 29. As shown, the impeller 30 can be disposed adjacent the bearing 44c such that rotation of the driven shaft 29 causes the impeller 30 to rotate within the housing 38. The vertical turbine pump 20 can include a diffuser 50, which diffuser 50 can be integral with the housing 38 at a location adjacent the impeller 30. The diffuser 50 can be slidably coupled to the driven shaft 29 adjacent the impeller 30 such that as the driven shaft 29 rotates, the diffuser 50 remains stationary within the housing 38. During operation of pump 20, fluid can flow proximally from inlet 40, through housing 38, through spacer 31, and into discharge tube 32. As the motor 22 drives the shafts 28 and 29, fluid can be drawn into the inlet 40, thus causing the shafts 28 and 29 to rotate about the L-axis, which in turn causes the impeller 30 to rotate about the L-axis.

Referring to fig. 4A, 4B, 5A, and 7, the impeller 30 can include a hub 46, the hub 46 configured to be mounted to the driven shaft 29 for rotation about a rotational axis that can be defined by the longitudinal L axis. The forward shroud 47 and the aft shroud 49 can extend radially outward from the hub 46 and are axially spaced from each other along the longitudinal direction L. A plurality of circumferentially spaced impeller blades 48 can extend between the forward shroud 47 and the aft shroud 49. At least one to all of the impeller blades 48 are capable of twisting about respective axes defined by a first directional component defined by the axis of rotation and a second directional component angularly (e.g., perpendicularly) offset from the first directional component defined by a direction substantially perpendicular to the axis of rotation. Thus, the impeller blades 48 can be referred to as mixed flow blades. Likewise, the impeller 30 can be referred to as a mixed flow impeller. The impeller 30 can be referred to as a containment impeller because both axial ends of the impeller blades 48 are attached to respective shrouds, such as the front shroud 47 and the rear shroud 49. During operation, rotation of the impeller 30 causes the vanes 48 to create a negative pressure in the suction horn 42 that draws fluid, such as water, through the impeller 30 into the housing 38.

Referring to fig. 4A, 4B and 5B, the diffuser 50 includes a hub 52 separated from the interior surface of the housing 38 by a gap defining a passage 54 for fluid flow through the housing 38. The diffuser 52 also includes a plurality of diffuser vanes 56 that project radially outward from the hub 52 to contact or attach to or against an interior surface of the casing 38. Thus, fluid forced into the housing 38 by the impeller 30 travels through the passage 54. The diffuser vanes 56 are each twistable so as to define a front surface relative to a direction of fluid flow that is twisted about a respective axis defined by a first directional component defined by the longitudinal L-axis and a second directional component angularly (e.g., perpendicularly) offset relative to the first directional component, defined by a direction that is generally perpendicular to the L-axis, and thus can be referred to as mixed flow vanes. The diffuser vanes 56 can also increase the surface area in the proximal direction of the fluid flowing through the passage 54. Thus, during operation, the diffuser vanes 56 are configured to reduce the velocity of the fluid flowing through the housing 38, which increases the head pressure. Thus, fluid pressurized by rotation of the impeller 30 during operation is driven to flow through the housing 38 and the discharge tube 32 and out the elbow 33.

While the vertical turbine pump 20 has been described in connection with an embodiment, it should be understood that the vertical turbine pump can be constructed in accordance with alternative embodiments. For example, the motor support 24 can be configured as desired. Further, as shown in fig. 6A, the vertical turbine pump 20 can have a motor support 24' that is improved relative to the motor support 24 shown in fig. 1A-1B. For example, the motor support 24' can lack the mounting plate 26.

Referring to fig. 6B, the vertical turbine pump 20 can be configured according to another alternative embodiment, and for example, the vertical turbine pump 20 can include a plurality of housings, such as housings 38' and 38 "connected in series and spaced apart along the longitudinal direction L. Each housing 38' and 38 "includes an integral diffuser and houses an impeller of the type described herein. During operation of the pump 20, the multiple housings 38 and impellers 30 being connected in series can create a higher pressure in the fluid being pumped than a single housing and impeller. It should be understood that vertical turbine pumps 20 according to other embodiments can include any number of housings, such as three or more housings connected in series, as desired. This embodiment can also include an integral diffuser and house an impeller in each housing. By using two or more casings and impellers in series, the pressure of the fluid flowing through the vertical turbine pump 20 is increased.

In accordance with one aspect of the present invention, it is recognized that it is desirable to manufacture the vertical turbine pump 20 from a non-metallic and, thus, non-corrosive material such as fiberglass. It is recognized that conventional molding techniques include Resin Transfer Molding (RTM) and compression molding. In RTM, reinforcing fibers such as glass fibers are oriented before resin is injected into a mold, and thus the strength of a molded part is improved in the direction of fiber orientation. In compression moulding, the orientation of the reinforcing fibres is generally less controlled or not, thus resulting in a compression moulded part having a greater thickness than an identical RTM moulded part having a given strength. Thus, since an RTM molded part can be made thinner than the same compression molded part, the following description describes a manufacturing process with respect to an RTM, but it should be understood that the present invention is not limited to an RTM and can include compression molding or any suitable alternative manufacturing technique as would be readily understood by a person skilled in the art.

In conventional RTM manufacturing, the molded part is removed from the mold in a direction by separating the dies. However, to construct the impeller blades 48 and diffuser blades 56 that twist both axially and radially, a mold core having the inverse shape of the molded part is disposed in the mold cavity. Unfortunately, reliable core materials have not been available for use in manufacturing components of the vertical turbine pump 20. For example, while it is well known that mold cores can be made from materials including ceramics, alloy materials having low melting points, and waxes, it has been found that while ceramics exhibit desirable strength to support the reinforcing fibers and maintain their structural integrity during the molding process, ceramics are stronger than the injected resin. Therefore, it is not feasible to reliably remove the ceramic core from the molded part because it results in damage to the molded part. The present inventors have recognized that alloy materials such as bismuth exhibit low melting points (e.g., lower than the melting point of the injected resin) and, thus, can be melted and removed from the molded part. However, the weight of bismuth is almost three times heavier than the injected resin and thus results in a molded structure that is too heavy and difficult to handle before the core is removed. In addition, low melting point alloys are difficult to machine and to maintain a desired shape after machining. For example, bismuth expands upon cooling. Eventually, any unmelted or hard bismuth present during start-up and operation may damage the pump. The present inventors have also recognized that wax cores are commercially viable, and that conventional waxes do not have the desired strength to withstand the forces generated during RTM or compression molding. For example, the inventors have found that during compression molding, the wax core undergoes structural failure as the resin is compressed inside the core. As such, the inventors have found that when using an RTM process, the wax core breaks when the reinforcing fibres are compressed against the core.

The present inventors have recognized that a "blue blend" processable wax, commercially available as "blue blend" from machinery wax. The "Blue Blend" wax has a specific gravity of 0.035 pounds per cubic inch, a hardness of 50 to 55 (shore hardness scale), a flash point of 575F, a softening point of 226F, a drop melting point of 227F, and a volume shrinkage of 5%, and is considered engravable by the inventors.

Referring to fig. 8A, wax can be molded into a desired wax structure 60 having a suitable shape to provide a mold core 62 disposed inside the mold cavity to facilitate production of an RTM manufactured impeller 30. Thus, the mold core 62 can be defined by the desired wax structure 60. Specifically, the mold core 62 defines the inverse of the structure of the impeller 30 such that the solid areas of the mold core 62 define open areas or air pockets of the impeller 30 that are free of material, while the open areas or air pockets are defined by the mold core 62 defining the solid structure of the impeller 30. According to the illustrated embodiment, the wax structure 60 is molded in the shape of a bowl having a central hub 63 at one end. To prevent cracking of the wax structure 60 as it cools, the molding dies that define the shape of the wax structure 60 can be made of silicone rubber. During the manufacture of the wax structure 60, the silicone rubber minimizes heat dissipation as the wax structure 60 hardens. A multi-axis Computer Numerical Control (CNC) machine can mill or otherwise machine the wax structure 60 with a cut 64 in the shape of the impeller blade 48.

Referring to fig. 8B, reinforcing fibers 70, such as glass fibers, are oriented in a desired direction, placed along the upper and outer surfaces of the mold core 62, and inserted through the cut-outs 64. As shown in fig. 8C-8D, the fiberglass load-bearing core 62 is placed in a mold cavity 72 defined between a pair of mold dies (one die 74 is shown), and resin 76 is injected into the mold cavity 72 to form an intermediate structure 78, the intermediate structure 78 including a solid uniform composite structure 80, the composite structure 80 including the resin 76 and the reinforcing fibers 70 carried by the mold core 62. The uniform composite structure 80 is a fiberglass reinforced resin according to the illustrated embodiment, and thus includes resin 76 and embedded reinforcement resin 70, such that the resin and fibers are integrally bound and uniform throughout. Once the composite structure 80 is hardened, the molding dies can be separated to reveal the hardened composite structure 80, as shown in fig. 8E. The composite structure 80 may be skived around its periphery to remove resin 76 disposed around the periphery of the mold core 62, as shown in fig. 8F.

If desired, the resin 76 can be any non-corrosive resin, such as a vinyl ester resin, an epoxy resin, or any alternative suitable resin. According to one embodiment, the composite structure 80 has a higher melting point than the wax pattern core 62. According to the illustrated embodiment, the wax core 62 melts at any temperature above 227 degrees Fahrenheit, such as about 267 degrees Fahrenheit, while the resin 76 and the composite structure 80 have a melting point above 350 degrees Fahrenheit. Mold core 62 also exhibits a specific gravity of greater than 0.034 pounds per cubic inch and a hardness of 50 to 55 shore hardness. Thus, as shown in fig. 9A-9C, the intermediate structure 78 can be subjected to heat that is higher than the melting point of the mold core 62 but lower than the melting point of the composite structure 80 in order to remove the mold core 62 from the composite structure 80 and produce the impeller 30. In particular, according to the illustrated embodiment, the intermediate structure 78 may be heated in order to cure the resin and melt the wax pattern core 62, thus removing the core 62 from the composite structure 80. Curing the composite structure 80 may require heating in excess of 200 degrees fahrenheit, so the intermediate structure 78 can be heated in order to cure the composite structure and simultaneously melt the wax core 62. The wax mold core 62 flows out of the intermediate structure 78 and leaves the molded impeller 30. The remaining wax remaining on the impeller 30 after the wax core 62 is melted can be flushed out of the pump 20 during operation. Unlike bismuth, the remaining wax is soft enough that it does not damage the vertical turbine pump 20 during normal operation.

Referring to fig. 10A-10C, a shell core wax structure 60' can be fabricated in a manner similar to that described above with respect to the wax structure 60 that provides a mold core for the construction of the impeller 30. Specifically, in addition to using a silicone rubber mold, a heat lamp can also be employed to prevent the wax at the open end of the mold from hardening before the wax at the bottom of the mold hardens. For example, the wax mold core 62 can have a thickness that increases from the closed portion to the open end. This technique allows the wax to cool slowly in a direction from the closed portion of the mold core 62 (e.g., the bottom of the mold core 62) toward the open end of the mold core 62, thus minimizing the likelihood of crack formation during cooling.

Thus, the wax structure 60' can provide a housing core 62', which housing core 62', although manufactured as described above with respect to core 62, is configured to manufacture the housing 38 with its integral diffuser 50. For example, the mold core 62' defines the inverse configuration of the housing 38 such that the solid areas of the mold core 62' define the open areas or air pockets of the material-free housing 38, while the open areas or air pockets defined by the mold core 62' define the solid configuration of the housing 38. Thus, the mold core 62' has the shape of a shell having a shape higher than the mold core 62 corresponding to the shape of the impeller 30 and defining a circumference larger than the circumference of the mold core 62. A multi-axis Computer Numerical Control (CNC) machine can mill or otherwise machine the wax structure 60 'with cutouts 64' in the shape of the diffuser vanes 56. Thus, resin is injected into the mold cavity and allowed to harden, and the mold core 62' is removed in the manner described above to produce and manufacture the housing 38 with its integral diffuser 50 relative to the mold core.

Around the core 62 'and within the core 62' are placed reinforcing fibers 70. As shown in fig. 10D, the fiberglass load-bearing core 62' can be placed in a molding cavity 72' defined between a pair of molding dies (one die 74' is shown). Fig. 10E shows the molding die after resin 76 has been injected into the molding cavity 72 'to form an intermediate structure (not shown) comprising a solid uniform composite structure comprising the resin 76 and the reinforcing fibers 70 carried by the core 62'. Once the composite structure has hardened, the mandrel 62' can be removed relative to the composite structure 78 in the manner described above, relative to manufacturing the mandrel, and the housing 38 with its integral diffuser 50.

It will be appreciated that the molded impeller 30 and housing 38 are both homogeneous, one-piece, solid components. That is, the parts of each component are manufactured as a single unitary structure in the form of glue, non-molded resin, bolts, fasteners, or other discrete connectors without joints. For example, the impeller blades 48 are integrally connected to the front 47 and rear shrouds 49. Likewise, the diffuser vanes 56 are integrally connected to the diffuser hub 52.

Referring now to fig. 11A, the joint 61 between the elbow 33 and the stuffing box support 27 can be made so that the shaft opening 58 receives the downward extending stuffing box support 27. These pipes are joined using hand lay-up techniques for glass fiber reinforced pipe transport to produce unconventional tees. In particular, a manufacturing tool such as element FT can be used to align the centerlines of the elbow 33 and the stuffing box support 27. Once the elbow 33 and stuffing box support 27 are aligned, reinforcing fibers 70, such as glass fiber sheets, can be manually oriented along the exterior surface of the elbow 33 and the exterior surface of the spanning joint 61 of the stuffing box 37 as shown in fig. 11B. If fiberglass sheets are used, the fibers 70 can be aligned lengthwise along the stuffing box support 27 and elbow 33 to provide stability to the joint 61. After placement of the fibers 70, resin can be coated on the outside surfaces of the elbow 33, the stuffing box support 27, and also across the joint 61. Since the resin is also coated on the fibers 70, it can be said that the outer surfaces of the elbow 33 and the stuffing box support 27 are made of the composite material 80. Furthermore, it can be said that the outer surfaces of the elbow 33 and the stuffing box support 27 are uniform.

The embodiments described in connection with the embodiments shown have been presented by way of illustration, and the invention is not intended to be limited to the disclosed embodiments. Furthermore, unless otherwise indicated, the structures and components of each embodiment described can be applied to the other embodiments described herein. Accordingly, it will be appreciated by those skilled in the art that the invention is intended to cover all modifications and alternative arrangements included within the spirit and scope of the invention, e.g., as set forth in the appended claims.

Claims (12)

1. A vertical turbine pump elongated in a longitudinal direction, the vertical turbine pump comprising:

a motor and a drive shaft rotatably coupled to the motor such that rotation of the motor causes the drive shaft to rotate;

a housing having an inner surface;

a mixed flow diffuser including a diffuser hub spaced from an inner surface of the casing, the diffuser further including a plurality of mixed flow diffuser vanes projecting outwardly from the diffuser hub to the inner surface of the casing and twisted so as to define surfaces that are curved in the following directions: the direction comprises a direction component in a longitudinal direction and a direction component in a direction substantially perpendicular to the longitudinal direction; and

a mixed flow impeller configured to be rotatably fitted inside the casing, the mixed flow impeller having an impeller hub, a plurality of impeller blades, and front and rear shrouds connected to opposite ends of the impeller blades, the impeller blades extending from the impeller hub in: the direction comprising a directional component in a longitudinal direction and a directional component in a direction substantially perpendicular to said longitudinal direction,

wherein the diffuser hub, the mixed flow diffuser vanes and the casing are collectively made of a non-metallic material and are a single uniform unitary, fiberglass-reinforced solid component formed by a die molding process that places a fiberglass load-bearing core in a single mold cavity defined between a pair of molding dies.

2. The vertical turbine pump of claim 1, wherein the pump comprises: a discharge head comprising a discharge cylinder, an elbow, and a stuffing box holder extending into the elbow at a joint; and a second non-metallic material that is a glass fiber reinforced non-metallic material and covers the joint.

3. The vertical turbine pump of claim 1, wherein the single mold cavity is a first single mold cavity, and the impeller hub, the plurality of impeller blades, and the forward and aft shrouds of the mixed flow impeller are made of a single, fiberglass reinforced unitary component formed by a die molding process that places a fiberglass load-bearing core in a second single mold cavity defined between a pair of molding dies.

4. The vertical turbine pump of claim 1, wherein the glass fibers are oriented so as to bond to the non-metallic material.

5. The vertical turbine pump of claim 1, wherein the non-metallic material is a resin.

6. The vertical turbine pump of claim 5, wherein the resin comprises a vinyl ester resin or an epoxy resin.

7. A mixed flow impeller for a vertical turbine pump, comprising:

an impeller hub configured to rotate about an axis of rotation;

a plurality of mixed flow impeller blades extending outwardly from the impeller hub, each of the impeller blades twisted so as to curve along an axis defined by a first directional component defined by the axis of rotation and a second directional component defined by a direction substantially perpendicular to the axis of rotation; and

a front shroud and a rear shroud connected to opposite ends of the impeller blades,

wherein the impeller blades, the impeller hub, and the front and rear shrouds are integrally formed with one another to define a single, uniform, unitary solid component formed by a die molding process that places a fiberglass load-bearing core in a single mold cavity defined between a pair of molding dies, and are made of resin and reinforcing fibers.

8. The mixed flow impeller of claim 7, wherein the fibers are oriented so as to bond to the resin.

9. The mixed-flow impeller of claim 7, wherein the resin comprises a vinyl ester resin or an epoxy resin.

10. A vertical turbine pump component comprising:

a diffuser hub; and

a housing having an inner surface spaced radially outwardly from the diffuser hub;

the diffuser hub including a plurality of mixed flow diffuser vanes projecting outwardly from the diffuser hub to an inner surface of the casing, each of the diffuser vanes twisted so as to curve along an axis defined by a first directional component and a second directional component, the second directional component being substantially perpendicular to the first directional component,

wherein the diffuser hub, the plurality of mixed flow diffuser blades and the casing are collectively made from a single uniform unitary solid component made using resin and reinforcing fibers formed by a die molding process that places a fiberglass load bearing core in a single mold cavity defined between a pair of molding dies.

11. The vertical turbine pump component of claim 10 wherein the fibers are oriented so as to bond to the resin.

12. The vertical turbine pump component of claim 10 wherein the resin comprises a vinyl ester resin or an epoxy resin.