Fluid reaction surfaces (i.e. – impellers) – Specific blade structure – Formed with main spar
Reexamination Certificate
2002-11-06
2004-09-28
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Specific blade structure
Formed with main spar
C416S235000, C416S24100B, C029S889000
Reexamination Certificate
active
06796770
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of impeller design and manufacture.
BACKGROUND OF THE INVENTION
A number of approaches have been proposed in the manufacture of impellers. In most cases, the manufacture is achieved through the formation of the desired shape(s) from plate substrate, for example formed sheet metal. A primary problem with this prior art approach is that, in many circumstances, it is difficult or impractical to use preferred durable materials, such as certain metals, to achieve the configuration desired. In order to obtain a hydrofoil impeller design, for example, the thickness of the impeller blade must vary along the mean chamber line from the leading edge of the impeller to the trailing edge. The shape and tortuosity can dramatically affect impeller performance, but are difficult to control using standard processing techniques.
Generally, shortcomings of the prior art arise from (1) difficulties in maintaining uniformity in mass production and (2) lack of adequate dimensional accuracy in complex patterns for use in current impeller technology. Additionally, modifying the shape of an impeller blade to achieve better impeller performance has many costs associated with the design, testing, and tooling required to arrive at the desired blade configuration. Thus, there is a need for an improved method for impeller design and manufacture.
With the increased use of Computer Aided Design (CAD) solid modeling systems, a new technique of manufacturing technology has emerged that enables translation of the CAD output data into a three-dimensional (3-D) physical object. This technology is commonly referred to as solid free form fabrication (SFF) or layer manufacturing, which entails building an object on a layer-by-layer and point-by-point basis. CAD with SFF technologies allow for greater repeatability which allows for high quality mass production of the object. Forming objects automatically in three dimensions is useful in verifying a CAD database, evaluating design feasibility, testing part functionality, assessing aesthetics, checking ergonomics of design, aiding in tool and fixture design, creating conceptual models and sales/marketing tools, generating patterns for investment casting, reducing or eliminating engineering changes in production, and providing small production runs.
On the other hand, the resin materials that are currently available for SFF are also subject to certain manufacturing and process limitations in structural stability and rigidity, in chemical resistance and abrasion, and in manufacturing cost.
Accordingly, the need exits for a cost effective solution to increasing impeller performance without the significant investment required for reconfiguring and tooling a new impeller blade. The present invention fulfills these and other needs, and overcomes the drawbacks of the prior art, at least to some extent.
SUMMARY OF THE INVENTION
It is therefore a feature and advantage of the present invention to provide methods and compositions for designing and fabricating impellers with a desired degree of improved dynamics, dimensional accuracy and stability, and corrosion and erosion characteristics.
The above and other features and advantages are achieved, in one aspect, through the use of novel impeller design and construction methods using preferably coupled with CAD software, computer-controlled SFF techniques, to manufacture at least a portion of an impeller blade. This approach allows impeller devices to be produced with high precision and optimum shape for the required process.
It is a still further aspect of the present invention to provide methods for imparting structural strength to the impeller apparatus and blades, preferably, by providing a metal skeleton to fit the interior of the blade.
It is yet another aspect of the instant invention to provide a method for the production of resin impellers that have desirable chemical and abrasion resistance characteristics and rigidity. Preferably, the entire resin-constructed impeller is electroless plated with a ductile material such as copper or nickel, followed by electrolytic plating of a metal such as nickel, cadmium, or chrome to provide hardness, and chemical and abrasion resistance.
It is still a further aspect of the present invention to provide an impeller comprising at least one blade having at least one blade segment fabricated using any one of a solid free form manufacturing technique. The blade preferably has an exterior surface and a skeletal support structure disposed inside the blade to support the blade.
It is still a further aspect of the present invention to provide an impeller comprising at least one blade having at least one blade segment fabricated using any one of a solid free form manufacturing technique.
It is still a further aspect of the present invention to provide an impeller blade having an exterior surface, comprising a metal-plated layer at least partially covering the exterior surface of the blade.
It is still a further aspect of the present invention to provide an impeller, comprising at least one blade having at least one blade segment fabricated using any one of a solid free form manufacture technique, said blade having an exterior surface and a metal-plated layer at least partially covering the exterior surface of the blade.
It is still a further aspect of the present invention to provide a method for making an impeller blade comprising the step of forming a matrix of sequential layers of polymer material using a solid free-form fabrication technique.
It is still a further aspect of the present invention to provide a method of manufacturing an impeller, comprising forming a matrix of sequential layers of polymer material using a solid free-form fabrication technique to form at least one blade segment having an exterior surface and metal-plating the exterior surface.
It is still a further aspect of the present invention to provide a method of manufacturing an impeller, comprising forming a matrix of sequential layers of polymer material using a solid free-form fabrication technique to form at least one blade segment having an exterior surface, and disposing a skeletal support structure with the blade segment.
It is still a further aspect of the present invention to provide an impeller comprising at least one blade segment fabricated using and one of a solid free form manufacture technique, and a means for providing supplemental structural support to said blade.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
REFERENCES:
patent: 2659444 (1953-11-01), Stanley
patent: 3799701 (1974-03-01), Rothman
patent: 4122673 (1978-10-01), Leins
patent: 4137619
Gigas Bernd
Hale Steve
Baker & Hostetler LLP
Kershteyn Igor
Look Edward K.
SPX Corporation
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