1. Field of the Invention
This invention relates to a pump or pumping assembly, arrangement or combination; and more particularly, to an improvement to an impeller and suction liner combination used therein.
2. Description of Related Art
In pumps used for solids handling, the primary cause of reduced life and premature failure is recirculation from the outer diameter of the impeller to the suction of the impeller. The solids in the flow abrade and erode the impeller and suction liner, reducing their ability to seal and increasing the severity of the problem as additional wear occurs.
According to some embodiments, the present invention may take the form of apparatus, such as a pump or pumping assembly, arrangement or combination for solids handling, comprising a suction liner in combination with an impeller. The suction liner has a suction liner spiral design. The impeller has forward curved impeller suction side pump out vanes. The suction liner spiral design and the forward curved impeller suction side pump out vanes are configured to handle solids so as to exclude abrasive solids from an impeller/suction side liner gap by increasing the resistance to slurry flow from a high pressure area at the periphery of the impeller, and expel the solids which do manage to enter the impeller/suction side liner gap by guiding the solids away from a suction eye of the impeller, so that abrasive erosion is substantially prevented to significantly reduce wear and a tight clearance is substantially maintained at the impeller/suction side liner gap between the impeller and the suction liner, which substantially prevents degradation of pump performance through excessive leakage.
According to some embodiments of the present invention, the suction liner spiral design and the forward curved impeller suction side pump out vanes are configured to handle solids substantially have a weight concentration (Cw)<about 40% and/or a solids size distribution <about 200 microns.
According to some embodiments, the present invention may also include one or more of the following features:
The suction liner spiral design may be configured with at least one of the following: one spiral or at least two overlapping spirals.
Each overlapping spiral may be configured to start at an outer periphery of an inner rim of the spiral liner and end at an outer rim or periphery of the suction liner.
Each overlapping spiral may be configured to start at an outer periphery of the inner rim of the spiral liner and end at an intermediate location between the inner rim and the outer rim or periphery of the suction liner.
The two overlapping spirals may be configured to start at opposite sides of an outer periphery of the inner rim and end at opposite sides of the outer rim or periphery.
The impeller may be configured with an inner rim and an outer rim or periphery, and the forward curved impeller suction side pump out vanes may extend from the inner rim and end at the outer rim or periphery.
The forward curved impeller suction side pump out vanes may also be spaced equidistantly about the impeller face.
The suction liner spiral design may be configured with an outside diameter that is dimensioned relative to a suction liner outside diameter based at least partly on a percentage of best efficiency flow pumped by the pump.
The dimension of the outside diameter of the suction liner spiral design relative to the pump liner outside diameter may be inversely related to the change in the percentage of the best efficiency flow pumped by the pump.
The dimension of the outside diameter of the suction liner spiral design relative to the pump liner outside diameter may be reduced if the percentage of the best efficiency flow pumped by the pump is increased.
The dimension of the outside diameter of the suction liner spiral design relative to the pump liner outside diameter may be increased if the percentage of the best efficiency flow pumped by the pump is decreased.
The present invention disclosed herein assists in moving solids away from the area in question and thereby improving both the service lifespan and efficiency of a pump or pumping assembly, arrangement or combination. This technology is an improvement of the technology disclosed in an earlier filed patent application no. WO 2005/038260 A1, corresponding to U.S. Pat. No. 7,766,605, assigned to the assignee of the instant patent application.
For example, experimentation has indicated that forward curved pump out vanes have a wear reducing effect in some situations, as do relationships between the spiral design, pump out vane design, solids size distribution, and solids concentration by volume or weight:
In slurries with a greater percentage (%) concentration by weight or volume, prevention of all suction side leakage is paramount. The designs disclosed herein act to exclude abrasive solids from the impeller/suction side liner gap by increasing the resistance to slurry flow from the high pressure area at the impeller periphery. The designs disclosed herein also expel solids which do manage to enter the gap by guiding them away from the suction eye of the impeller. By both expelling and excluding solids, abrasive erosion is substantially prevented and a tight clearance is substantially maintained at the gap between the impeller and suction side liner, which substantially prevents degradation of pump performance through excessive leakage.
These and other features, aspects, and advantages of embodiments of the invention will become apparent with reference to the following description in conjunction with the accompanying drawing. It is to be understood, however, that the drawing is designed solely for the purposes of illustration and not as a definition of the limits of the invention.
The drawings, which are not necessarily to scale, include the following Figures:
a is a plan view of a suction liner spiral design for about 50% best efficiency point (BEP) operation according to some embodiments of the present invention.
b is a plan view of a suction liner spiral design for about 80% BEP operation according to some embodiments of the present invention.
a is a plan view of forward curved impeller suction side pump out vanes according to some embodiments of the present invention.
b is a plan view of rear curved impeller suction side pump out vanes according to some embodiments of the present invention.
In the following description of the exemplary embodiment, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration an embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized, as structural and operational changes may be made without departing from the scope of the present invention.
According to some embodiments of the present invention, the suction liner spiral designs 142 (
a shows a suction liner spiral design generally indicated by the arrow 144 for about 50% best efficiency point (BEP) operation according to some embodiments of the present invention, where the suction liner spiral design 144 includes two overlapping spirals 144a and 144b.
b shows a suction liner spiral design generally indicated by the arrow 146 for about 80% best efficiency point (BEP) operation according to some embodiments of the present invention, where the suction liner spiral design 146 includes two overlapping spirals 146a and 146b.
In
In
In mathematics, a spiral is generally understood to be a curve which emanates from a central point, getting progressively farther away as it revolves around the point. The spirals shown in
In
In
Alternatively, and by way of comparison, for Cw>about 50%, the impeller 12″ may be used having an impeller face 120″ with five (5) back curved pump out vanes 124 (see
In
The arrangement between the shaft 16 and the impeller 12 is described in provisional patent application Ser. No. 61/365,947, filed 20 Jul. 2010, which was subsequently filed as regular utility application Ser. No. 13/186,647, filed on 20 Jul. 2011, claiming benefit to the earlier filed provisional application, both applications are hereby incorporated by reference in their entirety.
Although described in the context of particular embodiments, it will be apparent to those skilled in the art that a number of modifications and various changes to these teachings may occur. Thus, while the invention has been particularly shown and described with respect to one or more preferred embodiments thereof, it will be understood by those skilled in the art that certain modifications or changes, in form and shape, may be made therein without departing from the scope and spirit of the invention as set forth above.
This application claims benefit to patent application Ser. No. 61/366,319, filed 21 Jul. 2010, which is hereby incorporated by reference in its entirety.
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Number | Date | Country | |
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20120051897 A1 | Mar 2012 | US |
Number | Date | Country | |
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61366319 | Jul 2010 | US |