U.S. patent application number 10/170922 was filed with the patent office on 2003-12-18 for impeller assembly for centrifugal pumps.
This patent application is currently assigned to Hackett, William Franklin JR.. Invention is credited to Snider, Phillip.
Application Number | 20030231959 10/170922 |
Document ID | / |
Family ID | 29732637 |
Filed Date | 2003-12-18 |
United States Patent
Application |
20030231959 |
Kind Code |
A1 |
Snider, Phillip |
December 18, 2003 |
Impeller assembly for centrifugal pumps
Abstract
An impeller assembly for centrifugal pumps that enables
self-priming in a relatively short time period includes an impeller
and at least one winglet (e.g., six winglets with a trapezium
cross-sectional shape). The impeller includes an impeller body with
an eye opening therein. The eye opening is configured for the
passage of a fluid (e.g., water) therethrough when the impeller
assembly is in use. The impeller body also includes at least one
vane, with a leading end, disposed about the eye opening. The at
least one winglet is positioned to protrude into the eye opening of
the impeller body and may, for example, be coupled to the leading
end of the vane.
Inventors: |
Snider, Phillip;
(US) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Hackett, William Franklin
JR.
175 E. Alamo Drive
Chandler
AZ
85225-1221
|
Family ID: |
29732637 |
Appl. No.: |
10/170922 |
Filed: |
June 12, 2002 |
Current U.S.
Class: |
416/186R |
Current CPC
Class: |
F04D 9/02 20130101; F04D
29/2261 20130101 |
Class at
Publication: |
416/186.00R |
International
Class: |
F04D 029/24 |
Claims
What is claimed is:
1. An impeller assembly for a centrifugal pump, the impeller
assembly comprising: an impeller, the impeller including: an
impeller body with an eye opening therein, the eye opening
configured for the passage of a fluid therethrough when the
impeller assembly is in use; at least one vane disposed about the
eye opening, the at least one vane having a leading end; and at
least one winglet positioned to protrude into the eye opening of
the impeller body.
2. The impeller assembly of claim 1, wherein a cross-section of the
winglet is trapezoidal in shape.
3. The impeller assembly of claim 1, wherein a cross-section of the
winglet is triangular in shape.
4. The impeller assembly of claim 1, wherein a cross-section of the
winglet is oblong in shape.
5. The impeller assembly of claim 1, wherein the impeller body and
winglet are configured as a unitary whole.
6. The impeller assembly of claim 5, wherein the at least one
winglet is coupled to the leading edge of the at least one
vane.
7. The impeller assembly of claim 6, wherein there are six vanes
and six winglets and each of the six winglets is coupled to a
leading edge of a different vane.
8. The impeller assembly of claim 1, wherein the impeller assembly
is configured for use in a self-priming centrifugal pump.
9. An impeller assembly for a centrifugal pump, the impeller
assembly comprising: a rotatable impeller, the impeller including:
an impeller body with an eye opening therein, the eye opening
configured for the passage of a fluid therethrough when the
impeller assembly is in use; at least one vane disposed about the
eye opening, the at least one vane having a leading end; and at
least one winglet coupled to the leading edge of the at least one
vane and positioned to protrude into the eye opening of the
impeller.
10. The impeller assembly of claim 9, wherein there are six vanes
and six winglets.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates, in general, to pump
assemblies and, in particular, to impeller assemblies for
centrifugal pumps.
[0003] 2. Description of the Related Art
[0004] Centrifugal pumps are widely used in chemical, food,
irrigation and other industries to pump a variety of liquids (e.g.,
water) and liquid-solid mixtures. Centrifugal pumps are a type of
kinetic energy pump that imparts energy to a liquid through
centrifugal force produced by a rotating impeller. The energy is
used to increase the pressure of the liquid and move the liquid
from one point to another.
[0005] FIG. 1 is a simplified cross-sectional depiction of a
conventional centrifugal pump 10 that includes a stationary casing
12 and an impeller 14 with curved vanes 16 (also referred to as
"blades" and shown as lines for simplicity) and an axially-disposed
eye opening 18. Rotation of impeller 14, and thus curved vanes 16,
(e.g., by a motor [not shown] operatively coupled to impeller 14)
within stationary casing 12 reduces the pressure at eye opening 18
of the impeller, causing liquid to flow into eye opening 18 from a
suction inlet (e.g., an intake pipe, not shown).
[0006] Curved vanes 16 are configured to accelerate and direct the
liquid away from eye opening 18. Rotating curved vanes 16 of
impeller 14 direct the liquid outward by centrifugal force, into
stationary casing 12 and subsequently out a discharge exit 20. The
accelerated outward flow of the liquid (i.e., from eye opening 18
towards stationary casing 12) reduces the pressure at eye opening
18, allowing more liquid to enter eye opening 18.
[0007] A drawback of centrifugal pumps is that they must be
"primed" prior to use. "Priming" is the addition of liquid to the
casing in order to displace (i.e., evacuate) any entrained air,
create a liquid seal within the casing and, thereby, prepare the
pump for the initiation of liquid flow therethrough. Although
self-priming centrifugal pumps (i.e., a centrifugal pump that is
configured to automatically remove [evacuate] air from the suction
inlet and that may handle liquids, gases and liquid-gas mixtures)
are known, the time period required to complete a self-priming
process in such self-priming centrifugal pumps may be undesirably
long.
[0008] Still needed in the field, therefore, is a self-priming
centrifugal pump that may complete a self-priming process in a
relatively short time period. In addition, the self-priming
centrifugal pump should be or a relatively simple and easily
manufactured structure.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention provides an impeller assembly for
centrifugal pumps that enables self-priming in a relatively short
time period. In addition, the impeller assembly is of a relatively
simple and thus easily manufactured construction.
[0010] An impeller assembly for a centrifugal pump according to one
exemplary embodiment of the present invention includes an impeller
and at least one winglet. The impeller includes an impeller body
with an eye opening therein. The eye opening is configured for the
passage of a fluid (e.g., water) therethrough when the impeller
assembly is in use. The impeller body also includes at least one
vane, with a leading end, disposed about the eye opening. The
winglet(s) are positioned to protrude into the eye opening of the
impeller body and may, for example, be coupled to the leading end
of the vane.
[0011] The provision of winglet(s) in the eye opening of impeller
assemblies according to one exemplary embodiment of the present
invention has been demonstrated to significantly reduce the time
period required for a self-priming process when such impeller
assemblies are used in centrifugal pumps. It is postulated, without
being limiting, that this reduction is due to two effects. First,
when in motion during use of the impeller assembly, the winglet(s)
provide an air-foil-like dynamic with the eye opening that creates
a vacuum-differential (also referred to as "lift") effect. The
vacuum differential ("lift") effect enhances the evacuation of gas
(e.g., air) from the centrifugal pump during a self-priming
process. Second, moving winglet(s) serve to divide any gas bubbles
(e.g., air bubbles) with which they come into contact into smaller
gas bubbles. The smaller gas bubbles are more readily entrained in
liquid passing through the centrifugal pump and, therefore, quickly
evacuated from the centrifugal pump.
[0012] Furthermore, the inclusion of winglets in an impeller
assembly according to one exemplary embodiment of the present
invention results in simple and easily manufactured impeller
assembly.
[0013] A better understanding of the features and advantages of the
present invention will be obtained by reference to the following
detailed description that sets forth illustrative embodiments, in
which the principles of the invention are utilized, and the
accompanying drawings
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a simplified cross-sectional depiction of a
conventional centrifugal pump;
[0015] FIG. 2A is a simplified cross-sectional depiction of an
impeller assembly according to one exemplary embodiment of the
present invention;
[0016] FIG. 2B is a simplified cross-sectional depiction of the
impeller assembly of FIG. 2A along line A-A.
[0017] FIG. 3 is a drawing depicting the cross-sectional shape of a
winglet included in one embodiment of the present invention;
and
[0018] FIGS. 4A, 4B and 4C are simplified left-side, edge and
right-side depictions, respectively, of an impeller body included
in one embodiment of the present invention.
DESCRIPTION OF PREFFERED EXEMPLARY EMBODIMENTS
[0019] FIGS. 2A and 2B are simplified depictions of an impeller
assembly 100 for use in a centrifugal pump in accordance with one
exemplary embodiment of the present invention. Impeller assembly
100 includes an impeller 102 and six winglets 104 (shown in
cross-section in FIG. 3). Impeller 102 includes a first impeller
body 106 with an eye opening 108 therein, a second impeller body
110 (through which eye opening 108 also passes) and a keyway 112.
Eye opening 108 is configured for the passage of fluid (e.g.,
water) therethrough when impeller assembly 100 is in use in a
centrifugal pump.
[0020] Winglets 104 are configured to protrude within eye opening
108 (see, for example, FIG. 2B) of impeller 102 and are also
configured for movement in a predetermined pattern (e.g., the
circular pattern indicated by arrow A of FIGS. 2B and 3) when
impeller assembly 100 is in use in a centrifugal pump.
[0021] Referring to FIGS. 4A-4C, first impeller body 106 includes
six curved vanes 114 disposed within eye opening 108. Each of the
curved vanes 114 has a leading edge 116 that is located proximal to
eye opening 108. First impeller body 106, curved vanes 114 and
winglets 104 may be formed of any suitable material known to one
skilled in the art including, but not limited to, PET white
plastic.
[0022] In the embodiment of FIGS. 2A, 2B, and 4A-4C, a winglet 104
is coupled to the leading edge 116 of each curved vane 114 by, for
example, being formed as a unitary whole with curved vanes 114 of
first impeller body 106. Preferably, each winglet 104 is machine or
molded as a solid part of a corresponding impeller vane but may
also be a separate piece coupled appropriately, as one skilled in
the art will understand, to a corresponding leading edge.
Therefore, when first impeller body 106 and curved vanes 114 are
rotated (e.g., at a rotation speed in the range of 10 rpm to 3,500
rpm), winglets 104 move in a circular pattern within eye opening
108.
[0023] Preferably, entrance vane angles are selected from a chart
provided in various engineering books, such as, for example, "The
Pump Hand Book." Such a chart allows one skilled in the art to
select a preferred vane entrance angle using desired impeller
efficiency and impeller specific speed.
[0024] Winglets 104 are configured to operate as rudimentary wings
(i.e., airfoils) during movement in the predetermined pattern. This
airfoil characteristic of winglets 104 is illustrated in FIG. 3.
Winglets 104 have a trapezium (either quadrilateral or trapezoidal)
cross-sectional shape and may be considered to possess a "top" side
200 and a "bottom" side 202. Thus, winglets 104 substantially fill
corresponding vanes 114 as may be seen in FIG. 4C and therefore the
trapezium shape is preferable. The dimensions of sides 200, 202 are
likewise selected to substantially fill vanes 114. Once apprised of
the present disclosure, one skilled in the art will recognize that
other winglets of other cross-sectional shapes may be employed such
as, for example, triangular or oblong cross-sectional shapes.
[0025] When a fluid (e.g., water or air) flows past winglet 104 it
travels farther along top side 200 than over bottom side 202 (as
illustrated by the dashed arrows of FIG. 3) creating a vacuum
differential or lift effect within eye opening 108. This effect
facilitates evacuation of gas from a centrifugal pump during a
self-priming process. In addition, the movement of winglet 104
serves to divide (i.e., break-up) large air bubbles into smaller
gas bubbles that are more readily mixed with liquid and evacuated
during a self-priming process.
[0026] The provision of winglet(s) that protrude into the eye
opening of impeller assemblies according to one exemplary
embodiment of the present invention has been demonstrated to
significantly reduce the time period required for self-priming
processes. For example, test results indicate that a conventional
self-priming centrifugal pump that required five minutes to
complete self-priming when pumping water required only thirty
seconds when winglets were provided in the eye opening of the
centrifugal pump.
[0027] It should be understood that various alternatives to the
embodiments of the invention described herein may be employed in
practicing the invention. It is intended that the following claims
define the scope of the invention and that structures within the
scope of these claims and their equivalents be covered thereby.
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