U.S. patent application number 11/686759 was filed with the patent office on 2008-09-18 for impeller with anti-vapor lock mechanism.
This patent application is currently assigned to KEEPALIVE, INC.. Invention is credited to Thomas Joseph Vento.
Application Number | 20080226467 11/686759 |
Document ID | / |
Family ID | 39762904 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080226467 |
Kind Code |
A1 |
Vento; Thomas Joseph |
September 18, 2008 |
IMPELLER WITH ANTI-VAPOR LOCK MECHANISM
Abstract
An impeller for preventing air-lock in a pump, the impeller in
its basic embodiment includes a top plate, the top plate having a
center axis and a peripheral edge, a plurality of vanes, each vane
attached to the top plate, at least one small protrusion projecting
from the periphery of the top plate, and at least one ventilation
channel having an outlet located near the protrusion, and an inlet
located near the center axis of the top plate. The present
invention also contemplates a centrifuge pump and an aerator device
having the impeller of the present invention.
Inventors: |
Vento; Thomas Joseph;
(Tarpon Springs, FL) |
Correspondence
Address: |
AKERMAN SENTERFITT
P.O. BOX 3188
WEST PALM BEACH
FL
33402-3188
US
|
Assignee: |
KEEPALIVE, INC.
Tarpon Springs
FL
|
Family ID: |
39762904 |
Appl. No.: |
11/686759 |
Filed: |
March 15, 2007 |
Current U.S.
Class: |
417/53 ; 416/92;
417/410.1 |
Current CPC
Class: |
F04D 9/003 20130101;
F04D 29/2277 20130101 |
Class at
Publication: |
417/53 ; 416/92;
417/410.1 |
International
Class: |
F04D 9/00 20060101
F04D009/00 |
Claims
1. An impeller for preventing air-lock in a pump, the impeller
comprising: a top plate having a center axis, a top side, a bottom
side, and at least one orifice; a plurality of vanes, each being
attached to the top plate; at least one small protrusion projecting
from the periphery or the top side of the top plate; and at least
one ventilation channel having an outlet and an inlet.
2. The impeller according to claim 1, wherein the plurality of
vanes are radially attached to the top plate.
3. The impeller according to claim 1, wherein the plurality of
vanes are axially attached to the top plate.
4. The impeller according to claim 1, wherein: the vanes are
attached to the bottom side of the top plate; and the at least one
small protrusion projects from the top side of the top plate and
the each small protrusion is located near each orifice of the top
plate.
5. The impeller according to claim 1, wherein: the at least one
orifice is located near the center axis of the top plate.
6. The impeller according to claim 5, wherein the at least one
orifice includes an angled wall.
7. The impeller according to claim 1, wherein: the outlet of the at
least one ventilation channel is located near the periphery of the
top plate, and the inlet is located near the at least one orifice
of the top plate.
8. The impeller according to claim 1, wherein: the outlet of the at
least one ventilation channel is located near the protrusion, and
the inlet is located near the center axis of the top plate.
9. The impeller according to claim 1, wherein each vane is axially
hollow.
10. A pump comprising: a pump casing defining a pump chamber, the
casing having a top, a bottom, and a side; an electric motor; at
least one water inlet located on the bottom of the housing; at
least one water outlet located on the side of the housing; an
impeller operatively disposed within said pump casing for moving
liquid from the water inlet to the water outlet, the impeller
comprising a top plate having a center axis, a top side, a bottom
side, and at least one orifice; a plurality of vanes, each being
attached to the top plate; at least one small protrusion projecting
from the periphery or the top side of the top plate; and at least
one ventilation channel having an outlet and an inlet; pump drive
means extending through the pump casing bottom and connected to the
impeller; and means for mounting the housing and the pump means in
operative association.
11. A method for preventing air lock in a pump, the method
comprising the steps of: providing a centrifuge pump having an
impeller operatively disposed within said pump casing for moving
liquid from the water inlet to the water outlet, the impeller
comprising a top plate having a center axis, a top side, a bottom
side, and at least one orifice; a plurality of vanes, each being
attached to the top plate; at least one small protrusion projecting
from the periphery or the top side of the top plate; and at least
one ventilation channel having an outlet and an inlet; rotating the
impeller; creating a negative pressure near the outlet of the
ventilation channel; and suctioning the air accumulated near the
center axis of the impeller from the inlet to the outlet of the
ventilation channel.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to an impeller, and more
particularly, an impeller provided with an air-release mechanism to
prevent air-lock of a pump.
[0003] 2. Description of the Related Art
[0004] Rotary pumps are well known structures employed to pump
fluids from one location to another. Rotary pumps have been
developed for a number of different uses, ranging from fire engine
apparatus to volumetric dosing of commercially important materials.
Rotary pumps may be classified according to structural features of
their material propelling elements. An example of the most
commercially important types of rotary pump is the centrifuge
pump.
[0005] Most centrifuge pumps comprise a generically cylindrical
casing and an impeller, or a plurality of impellers mounted inside
the casing to drive a fluid through the pump. The pumps typically
operate by taking in a fluid and adding energy from the fluid by
kinematics means; thus, the fluid pressure is increased, by the
interaction of rotating blades or vanes with the fluid as it passes
through. This energy, however, provides several undesired side
effects such as air-locking of the pump.
[0006] The pressure of the fluid in a pump drops as it flows from
the suction flange through the suction nozzle and into the
impeller. The amount of pressure drop is a function of many
factors, including pump geometry, rotational speed, frictional and
hydraulic shock losses, and flow rate.
[0007] If the pressure at any point within the pump falls below the
vapor pressure of the fluid being pumped, vaporization or
cavitation will occur. Bubbles are formed as a result of this
pressure drop. Lower pressures in the impeller center axis are
caused by variations in velocity of the fluid and friction losses
as the fluid enters the impeller.
[0008] The bubbles are caught up and swept outward along the
impeller vane. Somewhere along the non-visible side of the impeller
vane, the pressure may once again exceed the vapor pressure and
cause the bubbles to collapse, producing the phenomenon called
air-lock.
[0009] During air locking, the pump not only fails to serve its
basic purpose of pumping the liquid, but also may experience
excessive noise and vibrations, internal damage, leakage from the
seal and casing, bearing failure, etc. The extent of the
air-locking damage can range from a relatively minor amount of
pitting after years of service to catastrophic failure in a
relatively short period of time. In summary, air-locking is an
abnormal condition on the pump that can result in loss of
production, equipment damage, and worst of all, personnel
injury.
[0010] In the prior art, air-lock is cleared from the pump by
turning the pump off, thus releasing the back pressure of air and
allowing the water in the pump outlet hose to descend back through
the pump, thereby forcing any trapped air out of the impeller
chamber. The pump is then restarted, and in theory, but not always
in practice, the pump resumes the normal pumping of liquid.
[0011] Numerous attempts have been made over the years to design a
pump, which prevents or relieves air-lock. One is an "anti-airlock"
pump manufactured by Rule. This pump incorporates a device, which
is designed to periodically detect whether there is air present at
the pump impeller. If air is detected at the pump impeller, the
device shuts the pump off, allowing air to leave through the
impeller output line. However, this device does not proactively
clear the air-lock, and the impeller pump may remain air-locked
during the interval between testing for air-lock.
[0012] U.S. Pat. No. 4,913,620 entitled "Centrifugal Water Pump" to
Kusiak et al. teaches a centrifugal water pump in which the pumping
chamber is horizontally oriented, and such chamber has two wall
portions or sectors of different radius. One wall portion has a
radius substantially the same as the outer most radial path of the
impeller blades, and the other wall portion has a radius
substantially constant, but slightly greater than the radius of the
radical path of the impeller blades. Connecting the two chamber
wall portions are terminal walls, one of which is located adjacent
to the outlet port. A first deflecting wall directs the pumped
water upward into the outlet port. A second deflecting wall breaks
up any air and air bubbles, and fills any space wherein air or air
bubbles could collect. The device of Kusiak et al. is mechanically
complex, and in order to function properly, the device requires the
divider wall to create a positive and negative pressure (as opposed
to a normal flow of water), which actually reverses the flow of
water, thereby allowing any trapped air to escape.
[0013] U.S. Pat. No. 4,087,994 entitled "Centrifugal Pump with
Means for Precluding Airlock" to Goodlaxson discloses a centrifugal
pump with means for precluding air lock wherein the impeller of the
pump includes finger-like projections on each blade which extend
radially outwardly from the impeller body into the outer annulus of
the pumping chamber. These projections cut through the liquid,
which has been centrifuged to the outer annulus, thus causing a
turbulence, which draws a portion of the liquid into the body of
the impeller for mixing with trapped air.
[0014] This mixing action causes the air to be centrifuged with
liquid and alleviates air lock in the pump. However, it should be
noted that the vortex formed at the inlet of the pump is not
reduced in size or eliminated.
[0015] U.S. Pat. No. 5,213,718 entitled "Aerator and Conversion
Methods," and U.S. Pat. No. 5,275,762 entitled "Aerator" to
Burgess, teach aerators wherein an impeller draws a water and air
mixture down through an upwardly directed impeller inlet into a
cavitation zone (i.e., the centrifugal pump is mounted upside down
compared to the normal operating position). When the centrifugal
pump rotates, the vacuum formed in the cavitation zone by rotation
of the impeller will draw air through the air tube into the
cavitation center axis where a portion of the air will be entrained
in the water flowing through the vane impeller and out the water
flow, directing means into the tank. Excess air drawn into the
cavitation center axis through the inlet tube can escape upwardly
through the water inlet, thereby preventing air-locking of the
impeller, as would occur if air were to accumulate in the
cavitation zone of a centrifugal pump mounted in the "normal" pump
operating position, with the water inlet opening downwardly. The
pump preferably floats on the water with the air/water inlet for
the centrifugal pump immediately below the surface. Such a system
has a number of attendant problems. First, a centrifugal pump is
designed to be operated in a certain orientation. The pump may be
operated upside down near the surface for periods of time without
damage; however, if operated upside down at depth for any length of
time, air in the motor housing will exit through the seal between
the motor shaft and the impeller, and water will enter the motor
housing, thereby causing damage. Further, if the pump is operated
on the surface, oxygenation of the water will occur near the
surface of the tank, and the lower reaches of the bait well will
not be aerated.
[0016] Further yet, if the pump is operated at depth, the design
must permit escape of excess air out through the water inlet so as
to prevent air-locking of the pump, or to permit flooding and
restarting of an air-locked pump. The design must thus anticipate
the various depths at which the pump may be operated, and the
air-escape parameters for each depth. Such a design cannot optimize
the air/water mixture for maximum oxygenation of the pump at every
given depth. As a result of these design constraints, the
oxygenation efficiency is adequate, but much less than optimal.
[0017] U.S. Pat. No. 4,917,577 entitled "High Speed Centrifugal
Aerator" to Stirling teaches a high speed centrifugal aerator
including (1) a frustro-conical shaped impeller chamber within
which is mounted a similarly shaped mismatched impeller with blades
significantly smaller than the chamber, the impeller chamber having
a bottom inlet, and the bottom inlet having a venturi gas inlet for
mixing gas with the flowing liquid. To be effective, the impeller
must operate at a very high speed in order for the flow of fluid
through the bottom inlet to be sufficient to create a suction on,
and draw gas through, the venturi gas inlet. This high flow rate
would render the aerator impractical for use in small applications
such as bait wells, since the high turbulence would be injurious to
the baitfish. More importantly, since the impeller blades are
significantly smaller than the impeller chamber, most of the fluid
does not come into contact with the blades. This may be desirable
where the objective is to achieve high flow and low agitation.
However, where the object is to achieve a high rate of mixing of
air into a relatively small volume of water, as would be required
in a bait well application, this high-speed centrifugal aerator is
entirely unsuitable. Finally, the venturi gas inlets must be narrow
to be effective as the pump is cycled through many ON-OFF periods,
during which the venturi gas inlets will be flooded and dried,
resulting in sedimentation and encrustation. The venturi jets will
require attention and cleaning over time.
[0018] It would therefore be an advantage in the art to provide an
impeller that eliminates or minimizes the above-mentioned and other
problems, limitations and disadvantages typically associated with
conventional pumps, and to prevent air lock of the pump
impeller.
SUMMARY OF THE INVENTION
[0019] It is an object of the present invention to provide an
impeller designed to prevent air-lock of the pump.
[0020] It is yet another object of the present invention to provide
an impeller, which prevents air lock of the pump and does not
require constant monitoring by the operator.
[0021] It is yet another object of the present invention to provide
a mechanism by which air-lock may be prevented in currently
available pumps.
[0022] It is yet another object of the present invention to provide
a pump for pumping water, sewage or other liquid material from one
location to another without having the problem of air lock.
[0023] Rotary pumps are designed to pump a non-compressible fluid
such as water, fuel, etc. An example of the most commercially
important type of rotary pump is centrifuge pumps.
[0024] In a centrifuge pump, the energy imparted to the impeller
blades is normally used to move the impeller blades against the
liquid to cause flow of the liquid through the impeller cavity,
developing a negative pressure or suction on the upstream side, and
a positive pressure or discharge head on the downstream side.
[0025] However, once air is introduced into the impeller cavity,
the impeller energy is diverted to first expanding air in the
negative pressure side of the impeller, and then re-compressing air
on the downstream side of the impeller. Further, as the volume of
air is increased (due to the negative pressure) on the inlet side,
this expanded air displaces the liquid, reducing the amount of
water sucked into the impeller cavity. As the air exits the
impeller cavity, it is compressed to reduce volume; this constant
compressing having the end effect of reducing the output at the
downstream side of the impeller.
[0026] Following extensive experimentation, the present inventor
was able to determine that conventional pumps could be modified so
as to prevent or clear air-locks by providing an impeller that in
its basic embodiment comprises: a top plate, the top plate having a
center axis and a peripheral edge; a plurality of vanes, each vane
attached to the top plate; at least one small protrusion projecting
from the periphery of the top plate; and at least one ventilation
channel having an outlet located near the protrusion, and an inlet
located near the center axis of the top plate.
[0027] The plurality of vanes can be radially or axially attached
to the top plate.
[0028] In the first preferred embodiment, the impeller for
preventing air-lock in a pump according to the present invention
comprises: a top plate, the top plate having a center axis, a top
side, a bottom side, and at least one orifice; a plurality of
vanes, each vane attached to the bottom side of the top plate; and
at least one small protrusion projecting from the top side of the
top plate, wherein the each small protrusion is located near each
orifice of the top plate.
[0029] In the second preferred embodiment, the impeller for
preventing air-lock in a pump according to the present invention
comprises: a top plate, the top plate having a center axis, a top
side, a bottom side, and at least one orifice; and a plurality of
vanes, each vane attached to the bottom side of the top plate; and
wherein the at least one orifice is located near the center axis of
the top plate.
[0030] In the third preferred embodiment, the impeller for
preventing air-lock in a pump according to the present invention
comprises: a top plate, the top plate having a center axis, a top
side, a bottom side, a periphery, and at least one orifice; a
plurality of vanes, each vane attached to the bottom side of the
top plate; and at least one ventilation channel having an outlet
located near the periphery of the top plate, and an inlet located
near the at least one orifice of the top plate.
[0031] In the fourth preferred embodiment, the impeller for
preventing air-lock in a pump according to the present invention
comprises: a top plate, the top plate having a center axis, a top
side, a bottom side; a plurality of vanes, each vane attached to
the bottom side of the top plate, wherein each vane is axially
hollow.
[0032] The present invention also contemplates a pump comprising: a
pump casing defining a pump chamber, the casing having a top, a
bottom, and a side; an electric motor; at least one water inlet
located on the bottom of the housing; at least one water outlet
located on the side of the housing; an impeller operatively
disposed within said pump casing for moving liquid from the water
inlet to the water outlet, the impeller comprising a top plate, the
top plate having a center axis and a peripheral edge; a plurality
of vanes, each vane attached to the top plate; at least one small
protrusion projecting from the periphery of the top plate; and at
least one ventilation channel having an outlet located near the
protrusion, and an inlet located near the center axis of the top
plate; pump drive means extending through the pump casing bottom
and connected to the impeller; and means for mounting the housing
and the pump means in operative association.
[0033] In the same way, the present invention includes a pump
having an impeller according to the second, third, and fourth
preferred embodiment of the present invention.
[0034] Finally, the present invention contemplates a method for
preventing air lock in a pump, the method comprising the steps of:
[0035] providing a pump having an impeller operatively disposed
within said pump casing for moving liquid from the water inlet to
the water outlet, the impeller comprising a top plate, the top
plate having a center axis and a peripheral edge; a plurality of
vanes, each vane attached to the top plate; at least one small
protrusion projecting from the periphery of the top plate; and at
least one ventilation channel having an outlet located near the
protrusion, and an inlet located near the center axis of the top
plate; [0036] rotating the impeller; [0037] creating a negative
pressure near the outlet of the ventilation channel; and [0038]
suctioning the air accumulated near the center axis of the impeller
from the inlet to the outlet of the ventilation channel.
[0039] The foregoing has outlined rather broadly the more pertinent
and important features of the present invention in order that the
detailed description of the invention that follows may be better
understood, and so that the present contribution to the art can be
more fully appreciated. Additional features of the invention will
be described hereinafter, which form the subject of the claims of
the invention. It should be appreciated by those skilled in the art
that the concept and the specific embodiments disclosed may be
readily utilized as a basis for modifying or designing other
aerators for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent structures do not depart from the spirit and
scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] For a fuller understanding of the nature and objects of the
present invention, reference should be made by the following
detailed description taken in with the accompanying drawings in
which:
[0041] FIG. 1 is a cross-sectional view of the pump having an
impeller according to the basic embodiment of the present
invention.
[0042] FIG. 2 is a top view of the impeller according to the basic
embodiment of the present invention.
[0043] FIG. 3 is a bottom view of the impeller according to the
basic embodiment of the present invention.
[0044] FIG. 4 is a perspective bottom view of the impeller
according to the basic embodiment of the present invention.
[0045] FIG. 5 is a top view of the impeller according to the first
preferred embodiment of the present invention.
[0046] FIG. 6 is a bottom view of the impeller according to the
first preferred embodiment of the present invention.
[0047] FIG. 7 is a perspective view of the impeller according to
the first preferred embodiment of the present invention.
[0048] FIG. 8 is a top view of the impeller according to the second
preferred embodiment of the present invention.
[0049] FIG. 9 is a bottom view of the impeller according to the
second preferred embodiment of the present invention.
[0050] FIG. 10 is a perspective bottom view of the impeller
according to the second preferred embodiment of the present
invention.
[0051] FIG. 11 is a top view of the impeller according to the third
preferred embodiment of the present invention.
[0052] FIG. 12 is a bottom view of the impeller according to the
third preferred embodiment of the present invention.
[0053] FIG. 13 is a perspective bottom view of the impeller
according to the third preferred embodiment of the present
invention.
[0054] FIG. 14 is a perspective bottom view of the impeller
according to the fourth preferred embodiment of the present
invention.
[0055] FIG. 15 is a top view of the impeller according to the
fourth preferred embodiment of the present invention.
[0056] FIG. 16 is a bottom view of the impeller according to the
fourth preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0057] The present invention is directed to a pump for pumping
water, sewage, or other liquid material from one location to
another. The pump includes an impeller, or impeller that is rotated
in moderately close proximity to a stationary plate or stator. The
stationary plate has a central, coaxial inlet through which liquid
passes, and is thereafter conveyed by centrifugal force along the
impeller-plate spacing to an outlet at the periphery of the
impeller and the plate.
[0058] The pump may be any conventionally available pump such as
centrifugal pump, an impeller pump, or a mixed flow. Preferably,
the pump is a centrifugal pump, such as a centrifugal rotary bilge
pump that is well known in the art.
[0059] Centrifugal pumps are classified into three
categories--submersible, dewatering and trash.
[0060] Submersible pumps offer contractors versatility on the job
site. These pumps are, by definition, submersible in water
containing solids up to one-quarter inch in diameter and less than
10 percent by weight. Submersible pumps are relatively inexpensive,
can run unattended, and are lightweight and quiet. They can pump
unwanted water from well casings, tunnels, shafts, flooded
basements, manholes, vaults, swimming pools, and field drainage
collection systems. They can also supply water-to-water fountains,
waterfalls and small irrigation projects.
[0061] Dewatering pumps are also somewhat inexpensive but do not
contain high-quality components. Centrifugal dewatering pumps
feature high-volume flow capabilities, are lightweight, and have a
compact design. The water being pumped must be relatively clean,
containing solids up to one-quarter inch in diameter and less than
10 percent by weight. These units are best suited for pumping water
from manholes, flooded basements, utility vaults, swimming pools,
lakes and barge holds. Dewatering pumps can also supply water to
rural fire trucks, water trucks and small irrigation projects.
[0062] In contrast, trash pumps cost more, but they contain
high-quality components. The construction and rental industries
often prefer this type of pump, which has high-volume flow
capabilities, is lightweight and compact, and has a pump housing
that you can easily open for cleaning. These pumps can handle
clean, muddy, mucky, and sandy or gravelly water with solids up to
2 inches in diameter and between 10 to 25 percent by weight. Trash
pumps can remove unwanted water from excavations less than 20 feet
deep, flooded basements, manholes, utility vaults, mining work,
swimming pools, lakes and barge holds.
[0063] The term "centrifugal pump" as used herein is intended to
mean a pump, which utilizes the throwing force of a rapidly moving
impeller. The liquid is pulled in at the center or center axis of
the impeller and is discharged at the outer rim of this impeller.
By the time the liquid reaches the outer rim of the impeller, it
has acquired considerable velocity. The liquid is then slowed down
by being led through either a volute or a conical housing. The
simplest method for converting dynamic pressure to static pressure
is to slowly increase the volute delivery channel area (e.g., a
taper of no greater than 8 degrees). This is known as a diffuser,
and is often used on small pumps. As the velocity of the liquid
decreases, its pressure increases. The shape of the outlet has the
effect of changing the low-pressure, high velocity fluid to high
pressure, low velocity. That is, some of the mechanical kinetic
energy is transformed into mechanical potential energy. In other
words, the velocity head is partially turned into a pressure
head.
[0064] The device according to the present invention will now be
discussed in greater detail by reference to the drawings.
[0065] FIG. 1 illustrates a cross-sectional view of the pump device
10 according to the present invention. The pump comprising: a
housing (not shown); a pump casing 20 defining a pump chamber, the
casing 20 having a top, a bottom, and a side; an electric motor 25;
at least one liquid inlet 30 located on the bottom of the housing;
at least one liquid outlet 40 located on the side of the housing;
an impeller 45 operatively disposed within said pump casing for
moving liquid from the liquid inlet 30 to the liquid outlet 40, the
impeller 45 comprising a top plate 50, the top plate having a
center axis 60, a plurality of vanes 70, each vane radially
attached to the plate 50, at least one small protrusion 80 slightly
projecting from the periphery 85 the top plate, and at least one
ventilation channel 90 located near each protrusion 80, each
ventilation channel 90 running from the periphery of the top plate
100 (exit) to an orifice 110 located near the center axis of the
top plate 120 (entrance), wherein when the impeller rotates, a
negative pressure is produce near the exit 100 of each ventilation
channel 90, wherein the negative pressure suctions the air
accumulate near the center axis 60 of the impeller, wherein the air
is release from the center axis 60 of the impeller via the orifices
110 and through the entrance 120 of the ventilation channels to the
exit 100 of the ventilation channel; pump drive means 130 extending
through the pump casing bottom and connected to the impeller 45; an
air inlet to introduce air into the housing; and means for mounting
the housing and the pump means in operative association.
[0066] The motor may be powered by any suitable means such as an
internal battery, an external portable battery, or via electrical
connections to the main electrical supply system of a boat (in
which case the electric drive motor includes insulated and encased
electrical conductors 140. The ends of the electrical connection
means may be provided with electrically conductive clamps (not
shown) whereby the clamps may be clamped to the terminals of an
electric battery or other source of electrical power. The portable
power supply (not shown) may be provided in a housing, which can be
mated, integral with the pump casing 20, or may be located outside
the motor casing and inside or outside the boat transom, in which
case external electrical connection means 140 are required.
[0067] The pump housing 20 is shaped so as to encompass the
impeller 45 and to define a liquid inlet 30 and a liquid outlet 40.
In the design as illustrated in FIG. 1, the liquid inlet area is
immediately below, and co-axial with, the drive shaft 130 and "eye"
of the impeller 60.
[0068] The impeller 45 comprises a top plate 50, which is fixed at
its center to the drive shaft 130. The impeller 45 is provided with
a plurality of vanes 70 which are attached radially or axially to
the impeller top plate 50. The vanes extend downwardly and are in
close tolerance with the bottom wall portion 150 of the housing
20.
[0069] The material of the impeller depends of the type of fluid
being pumped. In the majority of the cases, it is preferable that
the impeller be made of a non-corrosive material such as
plastic.
[0070] What differentiates the impeller of the present invention
from those known in the art is that the basic embodiment of the
impeller according to the present invention includes at least one
small protrusion 80 slightly projecting from the periphery 85 of
the top plate 50 and at least one ventilation channel 90 having an
outlet 100 located near each protrusion 80, and an inlet 120
located near the center axis of the top plate.
[0071] The air accumulated near the center axis of the impeller
enters the inlet 120 via an orifice 110 located near the center
axis of the impeller.
[0072] The operation of the pump will now be described. When the
electric motor 25 is energized, drive shaft 130 rotates, causing
corresponding rotation of the impeller 45 whereby water is drawn
into the water inlet 30 to the water outlet 40. When the impeller
rotates, the protrusions close the gap B between the impeller vanes
and the pump casing creating a decreasing cross-sectional area,
thus the velocity of the liquid increases, and the static pressure
decreases creating a venturi effect (Bernoulli's principle). In
other words, total system energy, i.e. sum of the potential and
kinetic energy, remains constant in a flowing system (neglecting
friction). The gain in velocity occurs at the expense of pressure.
At the point of minimum cross-section, the velocity is at a
maximum, and the static pressure is at a minimum.
[0073] The negative pressure suctions the air accumulated near the
center axis 60 of the impeller, thus the air is released from the
pump via the orifices 110 and through the entrance 120 of the
ventilation channels to the exit 100 of the ventilation channel.
FIGS. 2-4.
[0074] There is a further drop in pressure due to shock and
turbulence as the liquid strikes and loads the edges of impeller
vanes. The net effect of all the pressure drops is the creation of
a very low-pressure area around each ventilation channel.
[0075] In the first preferred embodiment, the impeller 150 for
preventing air-lock in a pump according to the present invention
comprises: a top plate 160, the top plate having a center axis 170,
a top side 180, a bottom side 190, and at least one orifice 200; a
plurality of vanes 210, each vane attached to the bottom side 190
of the top plate 160; and at least one small protrusion 220
projecting from the top side 180 of the top plate 160, wherein the
each small protrusion is located near each orifice 200 of the top
plate 160. FIGS. 5-7.
[0076] The protrusions in this embodiment act in the same manner as
the protrusions in the basic embodiment.
[0077] In the second preferred embodiment, the impeller 230 for
preventing air-lock in a pump according to the present invention
comprises: a top plate 240, the top plate having a center axis 250,
a top side 260, a bottom side 270, and at least one orifice 280;
and a plurality of vanes 290, each vane attached to the bottom side
270 of the top plate 240; and wherein the at least one orifice 280
is located near the center axis 250 of the top plate 240. FIGS.
8-10.
[0078] Each orifice includes an angled wall section (not shown).
The angled wall increases the speed of the fluid creating a venturi
effect in the impeller. Accordingly, due to the angle and velocity
of the fluid, thus suction is generated at the top side of the
impeller,
[0079] In the third preferred embodiment, the impeller 300 for
preventing air-lock in a pump according to the present invention
comprises: a top plate 310, the top plate having a center axis 320,
a top side 330, a bottom side 340, a periphery 350, and at least
one orifice 360; a plurality of vanes 370, each vane attached to
the bottom side 340 of the top plate 310; and at least one
ventilation channel 380 having an outlet 390 located near the
periphery 350 of the top plate 310, and an inlet 400 located near
the at least one orifice 360 of the top plate 310. FIGS. 11-13.
[0080] In the fourth preferred embodiment, the impeller for
preventing air-lock in a pump according to the present invention
comprises: a top plate 160, the top plate having a center axis 170,
a top side 180, a bottom side 190; a plurality of vanes 210, each
vane attached to the bottom side 190 of the top plate 160, wherein
each vane is axially hollow 215. FIGS. 14-16.
[0081] During an extensive research, applicant discovered that any
opening through the impeller will produce a drop in the pressure
near the area of the opening, thus the air accumulate near the
center axis of the impeller will be suctioned out of the impeller
though the opening.
[0082] In accordance with this invention, the pump can
automatically rid itself of air-lock. Thus, constant monitoring for
the presence of air-lock, so that corrective action can be taken,
is eliminated or reduced to a minimum.
[0083] It can, therefore, be seen that the design of the impeller
disclosed herein offers a unique constriction for preventing or
alleviating air-lock in a pump.
[0084] The output from the pump having an impeller according to the
present invention is uninterrupted, smooth and non-turbulent, so as
to provide optimal conditions.
[0085] Although this invention has been disclosed and described in
its preferred form with a certain degree of particularity, it is
understood that the present disclosure of the preferred form is
only by way of example, and that numerous changes in the details of
operation and in the combination and arrangement of parts may be
resorted to without departing from the spirit and scope of the
invention as hereinafter claimed.
* * * * *