1. Field of the Invention
This invention relates to centrifugal pumps of the industrial type and specifically relates to providing an assembly of components for converting a centrifugal pump having a vortex-type impeller to a centrifugal pump having a spiral-type impeller for expanding the usefulness of the pump and increasing pump operation.
2. Description of Related Art
Centrifugal pumps are used in many industries to pump either clear water or slurries, the latter of which contain both fluid and solid components. The solids content of slurries vary in type and size, but all slurries are abrasive to some degree on the components of the pump. Therefore, centrifugal pumps are structured with varying abilities to withstand the varying degrees of abrasiveness of slurries. Pumps are consequently selected for their ability to process slurries of a given abrasiveness.
A centrifugal pump of the vortex type is one example of a slurry pump that is particularly constructed to process very abrasive slurries. The impeller of a vortex pump is made of very hard metal materials to withstand highly abrasive types of slurries. The impeller is particularly shaped to receive the influent slurry so that the solids content is processed by the impeller in a manner that reduces the impact of the solids on the impeller, thereby lessening the degradation of the impeller. The impeller may be configured with recessed areas between the impeller vanes which further contribute to the ability to process the slurry while lessening the impact of the solids on the impeller. Such impellers are known as recessed vortex impellers.
While vortex impellers are well-suited for their intended purpose, it is a natural consequence of the construction of vortex impellers, especially recessed vortex impellers, that certain pump efficiency is sacrificed due to the fact that the impeller is recessed from the main flow path of the fluid entering the pump. Occasions arise where the nature of the slurry being processed in a given installation changes, such as in a municipal waste facility. While the vortex centrifugal pump that is installed in the facility may still be operational, the fact that a vortex pump is less efficient than other types of centrifugal pumps becomes problematic to the optimal operation of the plant. In many instances, the vortex pump may be shut down and the installation modified to bypass the vortex pump in favor of processing the influent in a more efficient manner.
Thus, it would be beneficial in processing industries to provide a means by which a less efficient vortex centrifugal pump may be converted to a more efficient type of centrifugal pump responsive to a change in the type of slurries being processed, and in doing so employ the same pump casing and drive system of the existing vortex centrifugal pump to avoid having to replace the entire pump or having to modify the entire installation, both of which are extremely costly to plant operation.
In accordance with the present invention, a components assembly is provided for replacing the vortex-type impeller and related elements of a vortex-type centrifugal pump to convert the centrifugal pump to a more efficient type of pump, such as a spiral impeller-type centrifugal pump, using the same pump casing, drive assembly and seal assembly of the existing centrifugal pump. The components assembly of the present invention is adaptable for use in converting virtually any centrifugal pump of one impeller type to a centrifugal pump of a different impeller type, but is described herein by way of example only with respect to converting a vortex impeller pump to a spiral impeller pump.
The component assembly of the present invention generally comprises a new and different type of impeller that is selected to replace the current impeller of the centrifugal pump for improved or application-adapted operation. The component assembly also includes a back plate for positioning between the new impeller and the drive side casing of the pump casing to adapt the new impeller to the pump casing. A back plate may not always be necessary in that the new impeller may be configured especially to be adapted to an existing pump casing.
The component assembly of the present invention also may comprise a suction cover that is adapted to the new and different type of impeller of the component assembly. The suction cover is configured for attachment to the existing pump casing. The component assembly may not necessarily include a new suction cover if the original suction cover of the pump can be used and/or adapted to the new type of impeller that is installed in the existing pump casing. It may require a special designing of the new impeller to accommodate the existing suction cover, however.
The back plate and suction cover of the component assembly of the present invention are particularly structured and configured for attachment to the existing pump casing of the centrifugal pump. That is, they are structured with attachment points for securement, usually by means of bolts or pins, to the pump casing.
In some pump conversions, depending on the type of new impeller being installed in the existing pump casing, the component assembly of the present invention may also include an impeller adapter member, or impeller flange, to adapt the new impeller to the back plate of the component assembly or to the existing pump casing of the pump. An impeller adapter member may not always be required to effect the conversion, however.
The component assembly of the present invention allows an existing centrifugal pump in an installation to be converted to a more efficient type of pump without having to remove and replace the entire pump from the installation, and allows the existing pump to have continued use in the installation rather than having to modify the installation to avoid use of the less efficient vortex pump, which substantially affects plant operation and cost efficiencies. The present invention also allows the use of existing piping dimensions which advantageously effects operation and cost efficiencies. These and other advantages of the present invention are described further in the detailed description of the drawings.
In the drawings, which illustrate what is currently considered to be the best mode for carrying out the invention:
The vortex centrifugal pump 10 further comprises a wear plate 36 that registers against and is bolted to the drive side casing 12, as best shown in
The vortex pump 10 also comprises a suction side cover 50 that bolts on to the volute casing 14. The suction side cover 50 has a centrally formed opening that defines the inlet 52 of the pump 10. It can be seen that slurry entering the pump 10 through the inlet 52 encounters the rotating vortex impeller 40 and is conveyed to the volute 54 of the pump 10, and then exits through the outlet 56 of the pump 10.
The component assembly 60 of the present invention is shown in
As best seen in
An impeller adapter 67 may also be provided as part of the component assembly 60 of the present invention to adapt the new type impeller to the existing pump casing 12, 14. The impeller adapter 67 may be configured for use alone or in tandem with a back plate 64 as illustrated. The impeller adapter is shown in
The new impeller 68 may, in turn, be secured to the impeller flange 66 by means such as bolts or pins 78. The impeller flange 66 is also formed with a central opening 80 for receipt of the terminal end 44 of the drive shaft 30 therein. The central opening 80 is axially aligned with a central opening 82 formed in the new impeller 68 through which a threaded bolt 84 is extended to secure the new impeller 68 to the terminal end 44 of the drive shaft 30.
The new impeller 68 of the present invention may be virtually any type of impeller that is suitable for use in a centrifugal pump. The new impeller 68 illustrated in
The component assembly of the present invention may also include a suction side cover 70 which is likewise configured to accommodate the configuration of the new impeller, or spiral-type impeller 68, as shown in
In converting the existing centrifugal pump 10 from, for example, a vortex impeller type to a spiral impeller type, in accordance with the invention, the old suction side cover 50 is unbolted from the volute casing 14, the vortex impeller 40 is unbolted from the terminal end 44 of the drive shaft 30 and the impeller 40 is removed from within the wear plate 36. The wear plate 36 is then unbolted from the drive side casing 12 and is removed. All other components of the pump remain in place, including the drive shaft 30.
The back plate 64 of the component assembly 60 of the present invention is then positioned within the circumferential drive side opening 72 of the volute casing 14 and registered against the drive side casing 12. The back plate 64 is then bolted in place against the drive side casing 12. The impeller flange 66 is next positioned over the terminal end 44 of the drive shaft 30 with the axially-extending collar 76 positioned through the central opening 74 of the back plate 64. The spiral impeller 68 is then positioned over the impeller flange 66 and is secured to the terminal end 44 of the drive shaft 30. The new suction side cover 70 is then positioned against and bolted to the volute casing 14 as shown. The newly configured pump 62 is then ready for operation
The component assembly of the present invention is provided for configuring an existing centrifugal pump of one type, defined by the type of impeller installed in the pump, to a new type of centrifugal pump having a different type of impeller. The component assembly thereby enables the conversion of an existing centrifugal pump to a new type of pump that can meet changes in pumping applications, or increase pumping efficiencies in a resident installation or pumping application. By enabling the conversion of a resident centrifugal pump to a new type of pump, operation costs are significant reduced since a whole new pump does not need to be installed and the amount of down-time required to provide the installation with a better or more efficient pump is significantly reduced.
Thus, the component assembly of the present invention can be adapted for use in converting virtually any type of centrifugal pump to a new type of pump. Hence, reference herein to specific details of the invention, particularly as may be illustrated in the drawings is by way of example only and not by way of limitation.
This application is a non-provisional application claiming priority to provisional patent application Ser. No. 60/475,104 filed Jun. 2, 2003.
Number | Date | Country | |
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60475104 | Jun 2003 | US |