Patent Application
20150285248
The present invention relates to an improved semi-positive displacement rotary pump. More particularly, the pump has an improved impeller with replaceable wiper inserts in the impeller lobes to improve the efficiency and performance.
The prior art includes many rotary pumps for pumping liquids such as water, oil, gasoline, and other materials. In such pumps, the tolerance of clearance between the impellers and the pump chamber is critical to the proper functioning of the pump. The clearance must be great enough so the impellers do not touch a pump chamber wall and destroy various components of the pump, yet small enough that the pump operates efficiently and with minimal vibration by pushing the liquid through the pump chamber. Moreover, such pumps must be made out of materials that can maintain the required critical tolerance and withstand extreme vibration. As such, rotary pumps are expensive to manufacture and may suffer from a lack of a high degree of tolerance. Furthermore, many rotary pumps are difficult and expensive to maintain since after excessive wear, the entire impeller(s) require replacement.
U.S. Pat. No. 1,348,772 to Auger, which is hereby incorporated by reference in its entirety, teaches the use of packing material, such as felt, on an end of each lobe of a rotary pump to help increase the efficiency of the pump. However, packing materials wear out quickly which reduces efficiency of the pump unless the packing material is replaced frequently. Additionally, materials such as felt are semi-porous which allows flow though the material and reduces efficiency. Furthermore, the packing material may come loose from the lobe at high speeds as the pump impellers rotate, which greatly reduces the efficiency of the pump, rendering it unusable.
U.S. Pat. No. 6,053,717 to Dixon discloses a rotary pump with a wiper feature incorporated in lobes of an impeller and is hereby incorporated by reference in its entirety. U.S. Pat. No. 6,053,717 to Dixon fails to disclose various novel aspects of the present invention including, for example, a pump whereby at least one wiper is in contact with at least one lobe throughout a full rotation (360°) of the pump. An impeller lobe is most efficient when in extremely close proximity with either a housing or another impeller. Without a small tolerance between the impeller lobe and either the housing or other impeller, excessive backflow occurs resulting in lower efficiency. Additionally, the interaction between the area where the surface of one lobe tip comes in close proximity with the other impeller can cause hydraulic hammering which causes vibration and unnecessary wear of the shaft bearings. A general need is recognized to reduce the void and increase the degree of contact and communication between the lobe tip and either the housing or other impeller while limiting vibration and damage to the pump.
Therefore, there is a need for a rotary pump having a high degree of tolerance which is relatively inexpensive to manufacture, maintains contact with either the interior chamber wall or other impeller, has an increased-wear replaceable wiper blades which does not come loose at high speeds, and which can be changed quickly and efficiently without significant expense.
Therefore, it is an object of the present invention to improve the efficiency of a rotary pump and to reduce the manufacturing costs of making such a pump. It is a further object of the present invention to provide an improved impeller which has removable, extended-wear wiper blades which can be replaced quickly and cost effectively. Another object is to assure contact between the wiper blades and either the housing or other impeller by a spring or other biasing means and by the shape of the interior chamber wall and other impeller. Another object is that each wiper blade has a retention means which keeps the wiper blade attached to the impeller lobe during high rotational speeds of the impellers. A further object is to provide a more efficient path of action between two lobes and/or a housing by increasing the locus of successive contact points therebetween. Another object is to provide an improved impeller which has removable, extended-wear wiper inserts located on at least one periphery or face of an impeller lobe. Another object is to assure contact between each impeller lobe facial wiper blade and the pump housing by a spring or other biasing means.
In one embodiment of the present invention, a positive displacement rotary pump is provided with an improved impeller having a plurality of lobes, each of the lobes comprising a plurality of removable wiper blade inserts with a surface in substantially constant contact with the chamber wall of the pump. Such an impeller improves the efficiency of the pump while decreasing the manufacturing cost of the pump as a result of reduced tolerances between the pump chamber wall and the end of the wiper blade. Spring or biasing means provided in connection with the blades provide a force against the wiper insert within an impeller of the present invention, maintaining the wiper insert in substantially constant contact with the interior chamber wall of a pump or other impeller, even after significant wear of the wiper insert.
In another embodiment of the present invention, a positive displacement rotary pump is provided with an improved impeller having a plurality of lobes, each of the lobes comprising a plurality of removable wiper blade inserts with a surface in substantially constant contact with the chamber wall of the pump. Each lobe further comprises a first and second facial wiper blade wherein the first facial wiper blade extends outwardly and is positioned substantially perpendicular to the top plane of the impeller lobe and extends along the top plane of the impeller lobe such that it bisects the top plane of the lobe and the second facial wiper blade extends outwardly normal to the bottom plane of the impeller lobe and extends along the bottom plane of the impeller lobe such that it bisects the bottom plane of the lobe. Spring or biasing means provided in connection with the blades provide a force against the first and second facial wiper inserts within an impeller of the present invention, maintaining the facial wiper inserts in substantially constant contact with the top and bottom surfaces of the pump chamber housing, even after significant wear of the wiper insert.
In a preferred embodiment, an impeller comprises generally rounded lobes for increasing contact points and creating a longer path of action with respect to additional components. The generally rounded lobes comprise wiper inserts disposed generally radially thereon. Wiper inserts are preferably distributed on a lobe at even radial spacing. In one embodiment, three wiper inserts are disposed along a radial terminus of a lobe. It will be expressly recognized, however, that the present invention is not limited to a three-wiper arrangement. It is contemplated that lobes of the present invention may comprise any number of wiper inserts on a lobe terminus.
In another embodiment, an impeller comprises generally rounded lobes for increasing contact points and creating a longer path of action with respect to additional components. The generally rounded lobes comprise wiper inserts disposed generally radially thereon as well as a first and second facial wiper insert. Wiper inserts are preferably distributed on a lobe at even radial spacing. In one embodiment, three wiper inserts are disposed along a radial terminus of a lobe. It will be expressly recognized, however, that the present invention is not limited to a three-wiper arrangement. It is contemplated that lobes of the present invention may comprise any number of wiper inserts on a lobe terminus. Similarly, facial wiper inserts are preferably distributed such that the first facial wiper blade extends outwardly normal to the top plane of the impeller lobe and extends along the top plane of the impeller lobe such that it bisects the top plane of the lobe and the second facial wiper blade extends outwardly normal to the bottom plane of the impeller lobe and extends along the bottom plane of the impeller lobe such that it bisects the bottom plane of the lobe.
In one embodiment, a pump is provided with a plurality of wiper inserts where each of the wiper inserts comprise a biasing member for biasing the wiper inserts in a radially outward manner thereby facilitating contact between wiper inserts and lobe features.
The present invention provides a novel timing sequence of a plurality of pump lobes which, in various embodiments, enables the pump to run dry for an indefinite time period without adversely affecting the pump components.
These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below. Further, the summary of the invention is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail in the summary of the invention, as well as, in the attached drawings and the detailed description of the invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this summary of the invention. Additional aspects of the present invention will become more readily apparent from the detailed description, particularly when taken together with the drawings.
Those of skill in the art will recognize that the following description is merely illustrative of the principles of the disclosure, which may be applied in various ways to provide many different alternative embodiments. This description is made for illustrating the general principles of the teachings of this disclosure invention and is not meant to limit the inventive concepts disclosed herein.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosures.
It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein.
The present invention has significant benefits across a broad spectrum of endeavors. It is the applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment of the method that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary method is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, can be modified in numerous ways within the scope and spirit of the invention, the invention being measured by the appended claims and not by the details of the specification.
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term be limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph.
It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted from these drawings. It should be understood, of course, that the invention is not limited to the particular embodiments illustrated in the drawings.
The present invention generally relates to an improved semi-positive displacement rotary pump. More particularly, the present invention provides an improved impeller for use in a rotary pump.
Referring now to
One advantage of the improved impeller for a rotary pump of the present invention is that the close tolerances of the clearance of the impellers 1a, 1b and the pump chamber 11 are not critical due to the impeller and wiper blade 8 design. In contrast, manufacturing tolerances which allow for the clearance of impellers 1a, 1b and pump chamber walls 11 as shown in the prior art are very critical. In these pumps, if the components are not within tolerance, the pump will not work due to loss of suction capacity and/or excessive vibration. In the pump of the present invention, the tolerances are not as critical, because the wiper insert is biased to extend outward from the lobe periphery 4 until prevented by the retention means which interferes with a wiper insert stop. This ability to extend to varying degree allows the wiper blade 8 to remain in substantial constant contact with the pump chamber wall 11 or other impeller assures peak efficiency.
Therefore, the pump of the present invention is less expensive to produce and can be made from a wider variety of materials than pumps previously utilized for similar uses. Prior to the present invention, similar pumps had to be made out of certain metals such as cast iron, aluminum, bronze, brass, and ferrous type metals, because the tolerances and the need to minimize vibration of the pump were critical. However, the wiper insert 8 improvement of the present invention allows the pump to be constructed with lower tolerances (i.e., greater distance between the pump chamber wall 11 and the impeller peripheries 3, 4). Thus, the pump can be made out of numerous types of materials, including, but not limited to, cast iron, bronze, stainless steel, fiberglass, plastic, aluminum, engineered polymers, thermoplastics, rubber composites, foam rubber and ferrous type metals.
As further shown in
For example, and still referring to
Yet another advantage of the improved rotary pump of the present invention is that the suction capability of the pump may be significantly and reliably increased over the suction capability of other rotary pumps since the wiper inserts of the present invention are more efficient, non-porous and wear evenly. A tighter seal is created during rotation because of constant contact of the wiper blade insert 8 with the chamber wall 11, which improves pump efficiency over the life of the wiper insert.
As shown in
Another advantage of the improved rotary pump of the present invention is that the wiper insert 8 is easy to replace, making it possible to maintain a tight seal for the life of the pump. Wiper inserts 8 of the present invention can be manufactured from a variety of materials including, but not limited to, rubber, nitrile, viton, polymers, nylon based resins, foam rubber, teflon and any other material which is generally wear-resistant and conducive to frictionally engage the surface of the pump chamber wall. Such a material can be selected to be compatible with materials from which the pump chamber wall 11 and impeller is constructed. Preferably, the wiper insert 8 is additionally compatible with the fluid serviced through the pump and thus custom designed for the particular pump application.
As shown in
Impellers of the present invention can have one or more lobes 3, 4. Preferably, an impeller of the present invention comprises three lobes. Each lobe 3, 4 of the impeller 1 has a first end or periphery, located proximal to the pump chamber wall 11, and a second end 5, located proximal to a central axis 2. The lobes 3 are commonly disposed approximately 120° apart in a preferred embodiment.
Each impeller 1 has a plurality of substantially arcuate cut-out portions 15. Each of the substantially arcuate cut-out portions 15 has a conjugate surface 28. The wiper insert 8 forms one or more seals over the conjugate surface 28.
The interaction between the wiper blade 7 and the conjugate surface 28 as the impellers 1 rotate, as well as the constant contact achieved therebetween, provide higher pump efficiency without any hydraulic hammering effect which causes unwanted vibration in the prior art.
According to one embodiment, each lobe periphery 4 has an interconnection means for securing a wiper insert 8 within a lobe. In certain embodiments, interconnection means are formed to removably, yet securely, hold the wiper insert 8 of the present invention such that the wiper insert 8 extends beyond the impeller lobe periphery and is maintained in substantially constant contact with the pump chamber wall 11 and/or conjugate surface 28 during rotation of the impeller. Insertion and assembly of the wiper blades are further shown in
Referring now to
Interconnection means, however, can be any shape, geometry, or arrangement suitable for holding the wiper insert 8 of the present invention in such a manner. Preferably, interconnection means comprise one or more cavities. The cavities comprise a narrow opening at a most distal edge of the lobe periphery such that the blade 7 of the wiper insert 8 is projected through the opening, while at least a portion of the blade member 7 and biasing member 9 is positioned within the cavity or channel.
In one embodiment, an impeller of the present invention has a biasing means 9 which is situated between the wiper insert and a back edge of the wiper insert cavity 10. The biasing means 9 provides substantially constant pressure on the wiper insert 8 such that the wiper insert 8 is pushed toward a pump chamber wall 11 or conjugate surface 28. That is, the biasing means 9 when compressed will have a tendency to expand outwardly toward the chamber wall 11 or conjugate surface 28. This biasing provides for extended wiper blade 7 life and improved pump efficiency. In one embodiment, the biasing means 9 comprises a mechanical type spring. Such a biasing element can be metal, plastic, rubber, or any similarly appropriate material. In another embodiment, the biasing means 9 comprises the material utilized for the wiper insert 8 as shown in
In addition, each lobe 3 in this embodiment has facial wiper inserts 58 located on each plane 82, 84 of the lobe 3, which extend between the shaft 2 of the impeller 1 and the end of the lobe 3 such that the facial wiper inserts 58 bisect the lobe 3. Further, each facial wiper insert 58 protrudes outward and substantially normal to the plane of the each lobe plane 82, 84. The various components of the embodiment according to
One advantage of the embodiment of
The blade 70 also has 3 protrusions 71, 72, 73 extending outwardly from the bottom plane of the blade 70. While this embodiment employs three protrusions 71, 72, 73, one skilled in the art would recognize that a variable number of protrusions could be employed. These protrusions 71, 72, 73 act to secure the blade 70 to the impeller lobe via a track embedded in the impeller lobe. The blades 70 of the present embodiment located at the end of the impeller lobe further have two cavities 74, 75 present at each end of the blade 70. The purpose of these cavities 74, 75 is to allow mating with the facial wiper blades 58. One skilled in the art will recognize, however, that these cavities 74, 75 are only employed in the impeller embodiment which utilizes the facial wiper inserts 58. When the blade 70 is used in the embodiment without facial wiper inserts 58, as show in
A preferred embodiment of a rotary pump of the present invention is depicted in
Bearings are used in a pump of the present invention to reduce friction. Such bearings are coupled, for example, to the axial shafts 42, 44. Preferably, the pump of the present invention comprises needle bearings 46, 48. Needle bearings used in a pump of the present invention provide significant advantages. For example, needle bearings are manufactured to hold closer tolerances, extend the life of the pump significantly, and allow less friction between pump components. Less energy is required to operate the pump due to better suction and discharge performance of the pump, thus requiring less maintenance than other types of bearings.
The pump comprises sleeves 50a, 50b pressed onto the shafts 42, 44 which provide strength to the shafts 42, 44. More particularly, the sleeves comprise an inner race for the bearing, which is pressed onto the shafts 42, 44. The sleeves generally increase the life of the bearing and the shafts because the bearing and sleeve, or inner race, are constructed of the same metals and therefore have the same hardness. This design enables the use of unlimited types of material to make the pump shafts. Additional sealing and gearing elements 52 are provided and generally housed within pump housing features 40, 54. Pressure safety means are provided, including exhaust port housing 56 for containing a safety valve.
The pump has seals comprised of mechanical seals, spring seals, packed seals, porcelain seals, spring reinforced lip seals, or any seal that physically fits the housing and shaft of the pump of the present invention. Preferably, the pump has high-pressure lip seals.
Devices of the present invention have been shown to provide significant, unexpected, and non-obvious improvements over prior art devices. As further illustrated by representative test data provided below, a 1.5″ pump comprising features of the present invention has been shown to achieve efficiency levels between approximately 93% and 98%.
While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein are capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. The use of “including,” “comprising,” or “adding” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof, as well as, additional items.
This Non-Provisional patent application is a Continuation-in-Part of U.S. patent application Ser. No. 13/763,940, filed Feb. 11, 2013, which claims the benefit of priority from U.S. Provisional Patent Application No. 61/597,569, filed Feb. 10, 2012, the entire disclosures of which are hereby incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 61597569 | Feb 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13763940 | Feb 2013 | US |
| Child | 14746493 | US |
