U.S. patent number 3,920,227 [Application Number 05/479,116] was granted by the patent office on 1975-11-18 for adjustable mixing device.
Invention is credited to Philip E. Davis, Jr..
United States Patent |
3,920,227 |
Davis, Jr. |
November 18, 1975 |
Adjustable mixing device
Abstract
An adjustable mixing device for mixing and blending fluids in a
container which has a fluid impeller adapted for pumping the fluids
substantially laterally in counter-rotating and circular continuous
motion in the container that is area-adjustable for varying the
volume of fluids pumped to adjust the torque load on the impeller
to prevent overload on the mixing motor during start-up. The
impeller of the mixing device can be adjusted from outside the
container without impeller removal.
Inventors: |
Davis, Jr.; Philip E. (Houston,
TX) |
Family
ID: |
23902722 |
Appl.
No.: |
05/479,116 |
Filed: |
June 13, 1974 |
Current U.S.
Class: |
366/329.1;
366/249; 416/149; 416/186R; 366/330.1; 210/219; 366/601; 416/121;
416/186A |
Current CPC
Class: |
B01F
7/1645 (20130101); Y10S 366/601 (20130101) |
Current International
Class: |
B01F
7/16 (20060101); B01F 005/16 () |
Field of
Search: |
;259/95,96,7,8,23,24,43,44,66,67,107,108,121,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jenkins; Robert W.
Attorney, Agent or Firm: Pravel & Wilson
Claims
I claim:
1. A mixing apparatus for agitating fluids in a container
comprising:
a. drive shaft means adapted to extend into a container,
b. support means for supporting said drive shaft means for axial
rotation;
c. driving means mounted with one end of said drive shaft means for
imparting a driving force thereto for axial rotation;
d. impeller means mounted with an opposite end of said drive shaft
means for immersion in a fluid in a container having a surface
coacting with the fluid for positively displacing a portion of said
fluid outward substantially laterally from the axial alignment of
said drive shaft means and into counter-rotating and circulating
turbulences within said container; and
e. area-adjusting means for adjusting the surface area of said
impeller means coacting with the fluid for varying the volume of
fluid positively displaced during axial rotation for controlling
the torque required from said driving means;
f. said impeller means comprising
1. a first impeller member having at least one blade member mounted
therewith;
2. a second impeller member having at least one blade member
mounted therewith;
3. said second impeller member being disposed in longitudinal
spaced relationship with said first impeller member to provide an
adjustable space therebetween and to provide a longitudinal
overlapping arrangement of said blade members for engagement of
said blade members to form an adjustable surface for said coacting
with a portion of the fluid;
4. one of said impeller members mounted with said drive shaft for
fixed axial rotation;
5. one of said impeller members rotatably mounted with said
area-adjusting means for axial rotation and adapted for
longitudinal movement relative to said other impeller member
whereby the fixedly mounted impeller member drives the rotatably
mounted impeller member during axial rotation; and
6. at least one of said impeller members having an axial opening to
provide for fluid flow in the container into the space between said
impeller members for positive displacement thereof substantially
laterally through said space by said longitudinally overlapping
blade members during axial rotation.
2. The mixing apparatus of claim 1, including:
means mounting said area-adjusting means for adjusting said
impeller meeans from the exterior of the container.
3. The mixing apparatus of claim 1, including:
anticavitation means adapted for mounting with said impeller means
for maintaining said fluid in the container substantially level
during said axial rotation.
4. The mixing apparatus of claim 1, wherein said driving means
includes:
a. speed control means mounted with said drive shaft means, and
b. motor means connected therewith for imparting a driving force
and rotation to said speed control means and drive shaft means.
5. The mixing apparatus of claim 1 wherein:
a. said first impeller member includes a first hub member mounted
with said drive shaft means and disposed in axial alignment
relative thereto, said first hub member having at least one blade
member mounted therewith; and
b. said second impeller member includes a second hub member
rotatably mounted with said area-adjusting means and disposed in
axial alignment relative to said drive shaft means and
longitudinally movable relative to said first hub member upon
actuation of said adjusting means, said second hub member having at
least one blade member mounted therewith.
6. The apparatus of claim 5 wherein said adjusting means
includes:
a. an adjustment rod having one end adapted for mounting with said
second impeller hub member and having an opposite end extending
exteriorly of said container, the longitudinal axis of said
adjustment rod being in substantial alignment with the longitudinal
axis of said drive shaft means; and
b. means mounted with said opposite end of said adjustment rod for
adjusting said adjustment rod upwardly and downwardly about its
longitudinal axis whereby said second impeller member is also
adjusted upwardly and downwardly relative to said first impeller
member to provide an increase or decrease in the total longitudinal
area of said blade members which coact with the fluid positively
displaced through the space between said impeller members.
7. The mixing apparatus of claim 6 wherein said means for adjusting
the adjustment rod includes:
an actuating member threadably mounted with said opposite end of
said adjustment rod and rotatable for axial adjustment of said
adjustment rod.
8. The mixing apparatus of claim 1 including:
a. an upper circular plate attached to the upper edge of said blade
member of said first impeller member; and
b. a lower circular plate attached to the bottom edge of said blade
member of said second impeller member and parallel to said upper
circular plate;
said blade members being longitudinally adjustable relative to each
other for positioning the lower edge of the first impeller blade
member and the upper edge of the second impeller blade member so as
to overlap each other in variable amounts upon adjustment thereof
by said adjusting means to transmit a driving force from one of
said impeller blade members to said other impeller blade member
during said axial rotation; and
at least one of said circular plates having said axial opening to
provide for said fluid flow into said space between said impeller
members.
9. The mixing apparatus of claim 8 wherein:
a. said first impeller member includes a first hub member mounted
with said drive shaft means and disposed in axial alignment
relative thereto, said first hub member having said blade member
mounted therewith; and
b. said second impeller member including a second hub member
rotatably mounted with said area-adjusting means and disposed in
axial alignment relative to said drive shaft means and
longitudinally movable relative to said first hub member upon
actuation of said adjusting means, said second hub member having
said second impeller blade member mounted therewith.
10. The mixing apparatus of claim 9 wherein said blade members of
each of said impeller members are respectively mounted with said
first and second hub members, each of said blade members having a
substantially arcuate shape and extending substantially laterally
from the respective axial alignments of each of said hub members to
the respective peripheries of said upper and lower circular
plates.
11. The mixing apparatus of claim 8 wherein:
said first impeller member includes a plurality of blade members;
and
said second impeller member includes a plurality of blade members.
Description
BACKGROUND OF THE INVENTION
The present invention relates to mixing devices and more
particularly pertains to apparatus for mixing and blending highly
viscous fluids such as drilling fluids, concrete, petroleum crudes,
aqueous oleaginous emulsions and the like.
Many viscous fluids, prepared by mixing or blending liquid and dry
granular ingredients, substantially immiscible liquids and the like
have tendencies to change viscosities and/or to separate into
layers upon standing. For example, drilling fluids prepared from
intimately mixed dry materials and liquids, gels and other special
ingredients, tend to "settle out" or precipitate upon standing into
thin liquid upper layers and heavy bottom residues or, in some
instances, to form thixotropic gels. This occurs frequently at oil
and gas well drilling sites due to constant interruptions in the
drilling operation. Another example is petroleum crudes which have
the tendency to form substantially undefined layers of differing
viscosities during storage.
The separation and viscosity change properties of these highly
viscous fluids create problems for conventional mixing devices
employed to remix these fluids to consistent viscosities
throughout. Due to these properties, large starting torques are
required to restart agitation of the fluids. Such large starting
torques place increased stress on the mixing device employed which
can result in frequent breakdown and repair problems. For example,
the required large starting torques can result in overloading the
mixing device power source, thereby causing damage thereto.
Moreover, increased energy is required to produce the large
starting torques required which may be unavailable or in reduced
supply in remote operating areas, such as the abovementioned remote
drilling sites.
DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 3,339,897 issued to the present inventor on Sept. 5,
1967, discloses a continuous mixing device for drilling fluids
which has a turbine-type impeller mounted with a driving shaft that
is rotated by a power source. The mixing device is believed to be a
substantial advance in the art of mixing devices useful for mixing
and remixing viscous fluids. However, it has been found that the
described mixing device can be overloaded during starting or
opertating under heavy torque loads caused by highly viscous or
dense fluids. The present invention is an improvement of the device
described in the aforesaid U.S. Pat. No. 3,339,897.
SUMMARY OF THE INVENTION
The present invention is an improved mixing device for agitating
fluids in a container that includes a mixing motor mounted with a
drive shaft that extends into the fluid with an area-adjustable
impeller mounted thereon. The area-adjustable impeller is adapted
for positively displacing or pumping the fluid in the container
outwardly substantially laterally from the drive shaft to provide
counter-rotating and circular currents in the fluid throughout the
container. The area-adjustable impeller is adapted for adjustment
to vary the volume of fluid positively displaced during rotation so
as to control the torque load on the motor during start-up and
operation. The impeller is adjustable from the exterior of the
container without removal of the impeller or mixing device from the
container.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view, partially schematic and partially in
section, of the mixing device of this invention with the improved
area-adjustable impeller in partial cross-section;
FIG. 2 is a cross-sectional view of the area-adjustable impeller
taken along line 2--2 of FIG. 1 which illustrates in detail the
impeller blades of the invention; and
FIG. 3 is a fragmentary view, partially in cross-section, which
illustrates certain details of the area-adjustable impeller of this
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 of the drawings, the improved mixing apparatus
of the invention, generally M, is adapted for mounting with a
container, generally C, which is preferably a large cylindrical
structure of large capacity including a cyclindrical wall 10 having
an annular flange 10a attached to its upper edge, a bottom 10b and
a circular roof 10c detachably mounted with the annular flange 10a.
Container C is provided with an inlet means 12 for admitting fluids
to be mixed into the container C and an outlet means 14 which
includes a valve 14a to control the fluid flow from the container
C.
The circular roof 10c is provided with an opening 10d that is
located substantially in its center and the mixing apparatus M is
mounted with the roof 10c in vertical alignment with opening 10d.
The mixing apparatus M includes a shaft means S extending
vertically through the opening 10d into the container C and an
impeller means I mounted at the lower end of the drive shaft means
S and disposed within the container C for immersion in and
agitation of a fluid in the container. The drive shaft means S
extends through a support means X which is provided for supporting
the drive shaft means S and impeller means I vertically within the
container C for axial rotation. The support means X is attached to
roof 10c about the roof opening 10d by any conventional means, such
as bolts, 10e.
The mixing apparatus M further includes driving means D mounted
with the upper end of the drive shaft means S for imparting a
driving force for axially rotating the drive shaft means S and the
impeller means I, and an area-adjusting means A for adjusting the
surface area of the impeller means I coacting with the fluid during
axial rotation for controlling the torque required from the driving
means D to provide the axial rotation.
As shown in FIG. 1, the drive shaft means S includes upper and
lower hollow drive shaft members 20a and 20b attached in vertical
axial alignment by means of rigid coupling members 21a and 21b
which are disposed substantially immediately below roof 10c within
the container C. Upper hollow shaft member 20a is mounted at
substantially its upper end with the driving means D and extends
through and is supportably mounted with the support means X. The
lower shaft member 20b has mounted at its lower end the impeller
means I which is located above the bottom 10b of the container C.
Preferably, the rigid coupling members 21a and 21b are bolted
together (not shown) so as to provide easy removal of the lower
drive shaft member 20b and the impeller means I for cleaning,
repair, storage, transfer and the like.
The upper hollow drive shaft member 20a extends vertically through
the roof opening 10d and through the support means X which includes
a support housing 30 mounted with the roof 10c and a plurality of
bearing means 31a and 31b mounted therewith and rotatably mounted
with the upper shaft 20a. The bearing means 31a, 31b are preferably
located at the upper and lower ends of the support housing 30 and
support the upper drive shaft means S and impeller means I for
axial rotation.
The upper hollow drive shaft member 20a also is mounted at
substantially its upper end with a speed control means R of the
drive means D. The speed control means R can be any conventional
type known in the art for varying the axial rotation speed and
drive force of the drive shaft means S and the impeller means I
under varying torque load conditions and is preferably a
conventional gear reduction box 40, as shown in FIG. 1 partially in
phantom. As known, such a gear reduction box 40 has a plurality of
driven gears 40a adapted for attachment with the upper drive shaft
20a and an equal plurality of driving gears 40b mounted with a
driving gear shaft 40c which is further attached at its upper end
with a driven pulley 40d. The driven gears 40a and the driving
gears 40b are adapted for engagement to provide predetermined
ratios between the speed of rotation of the drive shaft means S and
the speed provided at the driven pulley 40d. Speed and driving
force is provided at the driven pulley 40d by motor means such as
an electric motor 50 having a driving pulley 50a at one end
connected by a belt drive 50b to the driven pulley 40b of the gear
reduction box 40.
The gear reduction box 40 includes a gear housing 40e which can be
supported by attachment to the support housing 30 (not shown) if
desirable. The electric motor 50 can be supported by mounting with
the support housing 30 such as by means of a stanchion 50c.
The impeller means I of the mixing apparatus M is of turbine-type
construction including a plurality of area-adjustable impeller
blade means, generally B, extending outwardly substantially
laterally from the axial alignment of the impeller means I and the
drive shaft means S for positively displacing a portion of the
fluid in the container C outwardly and laterally in
counter-rotating and circular turbulences or currents to accomplish
the desired fluid mixing. The impeller blade means B are
area-adjustable and coact with the fluid for varying the volume of
fluid positively displaced during rotation so as to reduce the
torque load required to axially rotate the impeller means I. More
particularly, the impeller means I is illustrated in FIG. 1 as
including an upper impeller 60 mounted with a driving hub 61 which
is in turn mounted with the lower end of the hollow drive shaft
member 20b and extends axially therewith. The upper impeller 60
includes a plurality of arcuate-shaped driving blades 62 attached
at their respective inward tips 62a to the driving hub 61 that
extend outwardly substantially laterally to the axis of the hub 61.
The driving blades 62 are disposed so as to provide vertical
longitudinal fluid displacement surfaces relative to the vertical
axis of driving hub 61 and drive shaft means S. An upper circular
plate 63 is transversely attached to the upper edges of the driving
blades 62 and has an axial opening 64 about the driving hub 61
which defines an axial intake means 64a for drawing a portion of
the fluid to the impeller blade means B for positive outward
displacement as more particularly described hereafter. The upper
circular plate 63 has a radius substantially equal to the distance
the arcuate driving blades 62 extend laterally from the driving hub
61.
The impeller means I further includes a lower impeller 70 mounted
with a driven hub 71 which is in axial alignment with driving hub
61 and is supportably mounted with the area-adjusting means A. The
lower impeller 70 is adapted for axial rotation and for upward and
downward longitudinal movement relative to the upper impeller 60.
The lower impeller 70 also includes a plurality of arcuate-shaped
driven blades 72 attached at their respective inward tips 72a to
the driven hub 71 and extend outwardly substantially laterally
therefrom. Driven blades 72 are parallel relative to driving blades
62 and are thus disposed to provide vertical longitudinal fluid
displacement surfaces relative to the axis of the drive shaft means
S and impeller means I. A lower circular plate 73 is transversely
attached to the lower edges of the driven blades 72 that is
parallel to the upper circular plate 63 to provide a space
therebetween through which the portion of fluid is outwardly
positively displaced. Lower circular plate 73 has a radius
substantially equal to the distance driven blades 72 extend
laterally from driven hub 71 and has an axial opening 74 which
defines an axial intake means 74a for drawing a portion of the
fluid inwardly for positive outward displacement.
Upper impeller 60 and lower impeller 70 are positioned relative to
each other so that the lower edges 62b of driving blades 62 and the
upper edges 72b of driven blades 72 overlap to provide an
interference fit. In operation, the rotational driving force
provided by driving means D through drive shaft means S to the
upper impeller 60 is imparted by driving blades 62 to the driven
blades 72 so as to cause the upper impeller 60 to drive the lower
impeller 70. The interference fit of driving blades 62 and driven
blades 72 also provide longitudinal areas between upper circular
plate 64 and lower circular plate 74 which coact with the portion
of the fluid to positively displace it outwardly from the impeller
means I axis.
Referring now to FIG. 2, which is a cross-sectional view of the
impeller means I taken along line 2--2 of FIG. 1, the plurality of
impeller blades 62 are spaced equidistant apart. An equal plurality
of driven blades 72 are spaced equidistant apart and positioned
between the driving blades 62. Each of the driving blades 62 and
driven blades 72 have arcuate shapes and extend outwardly so that
the respective outward tips 62c, 72c are behind the respective
inward tips 62a, 72a attached to the respective driving hub 61 and
driven hub 71. FIG. 2 also specifically illustrates the overlapping
relationship and interference fit of the lower edges of driving
blades 62 with the upper edges of driven blades 72.
Referring again to FIG. 1, the lower impeller 70 and driven hub 71
are supported relative to the upper impeller 60 and driving hub 61
for upward and downward longitudinal movement by the area-adjusting
means A which includes an adjusting rod 80 adaptable for
supportable mounting at its lower end with the driven hub 71 and
extending axially within the hollow drive shaft means S and through
the speed control means R. The adjustment rod 80 is freely
rotatable relative to the hollow drive shaft means S. The lower end
of adjustment rod 80 is threadably mounted with a support nut 81
upon which the driven hub 71 rests. The upper end of adjustment rod
80 is threadably attached to an adjustment nut 82 which has a hand
wheel 83 attached thereto. The adjustment nut 82 engages at its
lower end the upper end 20c of the upper hollow shaft member 20a
and is supported thereon. Axial rotation of adjustment nut 82
raises or lowers the adjustment rod 80 longitudinally which in turn
raises or lowers the lower impeller 70. This raising and lowering
of lower impeller 70 accordingly increases and decreases the total
longitudinal area of impeller blades 62 and 72 which coacts with
the fluid so as to vary the volume of fluid positively displaced
outwardly during rotation of the impeller means I.
Referring now to FIG. 3, the cylindrical driving hub 61 is
illustrated as having an axial bore 61a through which the lower end
of the hollow drive shaft member 20b extends. The hollow shaft
member 20b and the hub 61 have respective grooves 20d and 61b
aligned with each other so as to receive a key K which locks them
together. A circular anticavitation plate 90 is attached by an
annular weld 90a to the upper end of the cylindrical driving hub 61
parallel to the upper and lower circular plates 63 and 72. As shown
in FIG. 1, the circular anticavitation plate 90 is spaced above the
axial intake means 64a. In operation, the anticavitation plate 90
prevents vortexing of the fluid and thereby prevents the entrance
of air into the intake means 64a.
Referring now to FIG. 3, the driving hub 61 is shown as also having
an axial bore 61c at its lower end that is adapted to receive the
driving hub 71 for upward and downward longitudinal movement
therein. Cylindrical driven hub 71 has a diameter slightly less
than the axial bore 61c and is disposed therein. Driven hub 71 also
has an axial bore 71a slightly in excess of the diameter of
adjustment rod 80. Adjustment rod 80, extending axially through
hollow drive shaft means S and being free to rotate relative
thereto, such as during longitudinal adjustment, also extends
through the bore 71a of the driven shaft 71. The adjustment rod 80
and the hub 71 have respective grooves 80a and 71b in alignment and
adapted to receive a key Y which locks them together. The support
nut 81 threadably attached to the lower end of adjustment rod 80
supports the driven hub 71 within the axial bore 61c of the driving
hub 61.
The driving blades 62 of the upper impeller 60 are attached by
welding, bolting or like attachment of their upward portions of
their inward tips 62a to the lower end of the driving hub 61 so
that the lower edges 62b extend below and beyond the driving hub 61
lower end. The driven blades 72 of the lower impeller 70 are
likewise attached to the lower end of the driven hub 71 at their
inward tips 72a. However, the driven blades 72 have notches 72d at
the upper portions of their respective inward tips 72a which are
adapted to receive the lower end of driving hub 61 when the driven
hub 71 is longitudinally raised in the driving hub axial bore 61c.
The driving blade lower edges 62b and the driven blade upper edges
72b are adapted to overlap in an interference fit while the driven
hub 71 is disposed within the driving hub bore 61c so as to impart
the rotational driving force to the lower impeller 70 as mentioned
hereinbefore.
As shown in FIG. 3, each of the impeller blades 62 and 72 have
respective curved leading edges 62d and 72e adjacent the respective
axial openings 64 and 74 of the respective parallel circular plates
63 and 73. These curved edges 62d and 72e bite portions of the
fluid in the container C during rotation so as to draw portions of
the fluid into the impeller means I for outward displacement during
rotation.
In operation, the mixing apparatus M of this invention can be
employed to intimately mix and agitate substantially any type of
viscous fluid, to blend wet and dry ingredients, or to blend fluids
capable of changing viscosity without the heretofore attendant
dangers of motor damage due to excessive torque loads. Since torque
loads and power requirements are usually the heaviest during
start-up of the mixing device M when the impeller means I is
immersed in a fluid in the container C, this description of
operation will begin therewith. Prior to initial start-up, it is
preferred to adjust the total longitudinal area provided by the
blade means B which coact with the fluid for positive displacement
thereof. This is accomplished by rotating the adjustment nut 82 in
the proper direction to raise or lower the adjustment rod 80 which
in turn longitudinally raises or lowers the lower impeller 70,
thereby decreasing or increasing the total longitudinal area of the
blade means B to that desired. The volume of fluid which can be
positively displaced outwardly during initial rotation is thus
varied to the desired amount which will result in a reduced torque
load required for rotation.
When power is supplied to the motor 50, a driving force is imparted
to the gear reduction box 40 which rotates the drive shaft means S
and the upper impeller 70. The rotational driving force is imparted
through the interference fit of the driving blades 62 and the
driven impeller blades 72 to rotate the lower impeller 70. During
rotation, a portion of the fluid is drawn through the intake means
64a and 74a and positively displaced outwardly substantially
laterally by the blades 62 and 72 coacting with the parallel upper
and lower plates 63 and 73. Continuous rotation of the impeller
means I causes continuous circular and counter- rotating
turbulences of the fluid within the container as shown by arrows T
in FIG. 1 whereby substantially all the fluid in the container C is
intimately mixed. The anti- cavitation plate 90 prevents vortexing
of the fluid, which thereby prevents excessive air bubbles during
mixing. The anticavitation plate, accordingly, maintains the fluid
in a substantially level position.
In the event it is determined that the torque load required for
rotation of the impeller means I in the particular fluid to be
mixed is too great, or in the alternative it is less than that
which the motor 50 can handle without damage, the adjustment nut 82
can be rotated in the proper direction so as to increase or
decrease the total longitudinal area of the blade means B coacting
with the fluid as described hereinbefore. Thus, it can be readily
appreciated that the adjustment can be made as desired to control
the torque load required for rotation.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape, and materials as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *