U.S. patent application number 11/450615 was filed with the patent office on 2007-12-13 for integrated mixing pump.
Invention is credited to Maynard Chance.
Application Number | 20070286745 11/450615 |
Document ID | / |
Family ID | 38822205 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070286745 |
Kind Code |
A1 |
Chance; Maynard |
December 13, 2007 |
Integrated mixing pump
Abstract
A mixing pump includes a power cylinder and a second cylinder
wherein one of the power cylinder and the second cylinder is
interchangeable between single and double acting and wherein a
working fluid is supplied to the power cylinder under pressure.
Inventors: |
Chance; Maynard; (Houston,
TX) |
Correspondence
Address: |
OSHA LIANG L.L.P.
1221 MCKINNEY STREET, SUITE 2800
HOUSTON
TX
77010
US
|
Family ID: |
38822205 |
Appl. No.: |
11/450615 |
Filed: |
June 9, 2006 |
Current U.S.
Class: |
417/397 ;
417/404 |
Current CPC
Class: |
F04B 9/113 20130101;
B01F 5/12 20130101; B01F 15/0216 20130101; B01F 5/0685 20130101;
F04B 5/02 20130101; B01F 15/0237 20130101 |
Class at
Publication: |
417/397 ;
417/404 |
International
Class: |
F04B 35/00 20060101
F04B035/00 |
Claims
1. A mixing pump comprising: a power cylinder; and a second
cylinder; wherein one of the power cylinder and the second cylinder
is interchangeable between single and double acting; wherein a
working fluid is supplied to the power cylinder under pressure.
2. The mixing pump of claim 1, wherein the power cylinder includes
a biasing mechanism.
3. The mixing pump of claim 1, further comprising a third
cylinder.
4. The mixing pump of claim 1, wherein one of the working fluid and
an additive fluid is supplied to the second cylinder.
5. The mixing pump of claim 4, wherein the additive fluid is at
least one of glycol and control system concentrate.
6. The mixing pump of claim 1, further comprising a fluid selector
valve coupled to the second cylinder.
7. The mixing pump of claim 1, further comprising a switch valve to
alternately direct the working fluid between a first chamber and a
second chamber of the power cylinder.
8. A mixing pump comprising: a power cylinder; a second cylinder;
and a third cylinder; wherein a working fluid is supplied to the
power cylinder under pressure.
9. The mixing pump of claim 8, wherein at least one of the power
cylinder, the second cylinder, and the third cylinder is
interchangeable between single and double acting.
10. The mixing pump of claim 8, wherein at least one of the working
fluid and an additive fluid is supplied to at least one of the
second cylinder and the third cylinder.
11. The mixing pump of claim 10, wherein the additive fluid is at
least one of glycol and control system concentrate.
12. The mixing pump of claim 8, wherein the working fluid is
potable water.
13. The mixing pump of claim 8, further comprising a switch valve
to alternately direct the working fluid between a first chamber and
a second chamber of the power cylinder.
14. A mixing pump comprising: a first cylinder, a second cylinder,
and a piston assembly; a first piston of the piston assembly
dividing the first cylinder into a first chamber and a second
chamber; a second piston of the piston assembly dividing the second
cylinder into a third chamber and a fourth chamber, wherein the
second piston is displaced by the first piston; a pressurized
working fluid connected to a switching mechanism, wherein the
switching mechanism is configured to alternately communicate the
pressurized working fluid between the first and second chambers of
the first cylinder to displace the first piston; and a first
additive fluid connected to an inlet of one of the third and the
fourth chambers of the second cylinder; wherein the pressurized
working fluid and the additive fluid are outputted to a supply tank
as the piston assembly reciprocates within the first and second
cylinders.
15. The mixing pump of claim 14, wherein the first and second
cylinders are sized to output a specified ratio of the pressurized
working fluid and the first additive fluid.
16. The mixing pump of claim 14, wherein a second additive fluid is
connected to an inlet of the other of the third and fourth chambers
of the second cylinder.
17. The mixing pump of claim 16, wherein the first and second
cylinders are sized to output a specified ratio of the pressurized
working fluid, the first additive fluid, and the second additive
fluid.
18. The mixing pump of claim 14, wherein the first additive fluid
is connected to an inlet of the other of the third and fourth
chambers of the second cylinder.
19. The mixing pump of claim 14, further comprising: a third
cylinder; a third piston of the piston assembly dividing the third
cylinder into a fifth chamber and a sixth chamber, wherein the
third piston is displaced by the first piston; and a second
additive fluid connected to an inlet of at least one of the fifth
and sixth chambers of the third cylinder.
20. The mixing pump of claim 19, wherein the first, second, and
third cylinders are sized to output a specified ratio of the
pressurized working fluid, the first additive fluid, and the second
additive fluid.
21. The mixing pump of claim 14, wherein the pressurized working
fluid is switchably connected to an inlet of at least one of the
third and fourth chambers of the second cylinder.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a mixing system.
More particularly, the invention relates to a mixing system for
pumping two or more liquids from storage tanks to a supply
tank.
[0003] 2. Background Art
[0004] There are numerous situations in which it is necessary to
pump a mixture of fluids created from multiple sources. In the
chemical industry and the fuel industry, it is desirable to control
proportions within a mixture. For example, offshore oil drilling
rigs often use water based fluids for hydraulic power for subsea
control systems. Hydraulic fluids are typically low viscosity
fluids used for the transmission of useful power by the flow of the
fluid under pressure from a power source to a load. A liquid
hydraulic fluid generally transmits power by virtue of its
displacement under a state of stress with low compressibility.
[0005] Hydraulic power is often used to actuate subsea tools. One
example of a subsea control system that uses hydraulic power is a
blowout preventer ("BOP"). A BOP forms a seal around drill string
to seal off well-head pressure when an area of high pressure, such
as a high pressure gas pocket, has been contacted during drilling.
A BOP may use hydraulic fluid to actuate numerous components of the
BOP. For example, hydraulic actuators may be used to move BOP rams
axially within a bonnet assembly in a direction generally
perpendicular to a wellbore axis.
[0006] At present, many conventional hydraulic fluids are not
suitable for subsea applications due to their low tolerance to sea
water contamination or to contamination by hydrocarbons. For
example, conventional hydraulic fluids tend to readily form
emulsions with small amounts of hydrocarbons. Furthermore, in
marine environments, problems may arise due to bacterial
infestations in the hydraulic fluid, especially from anaerobic
bacteria, such as sulfate reducing bacteria prevalent in sea water.
Additionally, though some conventional hydraulic fluids are
substantially non-corrosion-resistant, many, in fact, cause
corrosion with metals in contact with the fluid. Other conventional
hydraulic fluids are reactive with paints, metal coatings, and
elastomeric substances. Further, depending on the location of the
control systems in which hydraulic fluids are used, the freezing
point of the hydraulic fluid may need to be lowered.
[0007] Accordingly, in order to create a hydraulic fluid that may
be used in a particular system, multiple additives may be combined
with a base fluid. The majority of base fluids are potable water.
In some instances, a hydraulic or BOP control fluid concentrate may
be added to potable water. Control fluid concentrates are additive
fluids that may be used, for example, to provide lubricity for
moving parts in the control system, prevent corrosion of ferrous
metal alloys, provide anti-wear properties, and provide a biocide.
A biocide, also known as a bactericide, is an additive that
prevents growth of micro-organisms. Commercially available examples
of control fluid concentrates include Erifon HD 603HP, provided by
MacDermid (Pasadena, Tex.), and Stack Magic, provided by Houghton
Offshore (Houston, Tex.). At standard dilution ratios, control
fluid concentrates and working fluids may be used at temperatures
down to 32.degree. F. (0.degree. C.). In instances having
operational temperatures below 32.degree. F. (0.degree. C.), a
glycol additive may be used to lower the freezing point of the
hydraulic fluid.
[0008] These fluids (working and additive fluids) are commonly
mixed on a rig and stored in a supply tank. The ratio of the
components of the mixture must be accurate enough to provide the
right amount of biocide, lubricity, wear, and anti-freeze
protection. Incorrect ratios of the components of the mixture may
cause premature wear or failure of control system components.
Alternatively, excess additive amounts are costly.
[0009] Generally, once the ratios of components of a control system
fluid are determined for a particular application, the ratio does
not change. However, if the ratio is changed, it is usually based
on a change in operational temperature to accommodate fluctuations
for the need of glycol.
[0010] Currently, there are generally two types of mixing systems
used to mix multiple fluids into a hydraulic fluid for use in
subsea control systems. The first mixing system includes an
individual pump and motor for each fluid component. In this system,
each component fluid may be stored in a separate storage tank and
separate motor driven pumps supply each component fluid to a supply
tank. Accordingly, variations in the calibrations of the pumps or
variations in the water supply pressure may result in an inaccurate
mixture. Additionally, failure of a single motor may result in an
inaccurate mixture. Further, as space is limited on ocean rigs, it
is often difficult to provide sufficient space for three storage
tanks, three pumps, and three motors, in addition to a supply
tank.
[0011] A second, less common, mixing system includes a single motor
with multiple drive belts coupled to multiple pumps. In this
system, each component fluid may be stored in a separate storage
tank and separate pumps driven by a single common motor with
multiple belt drives supply each component to a supply tank.
Variations in water supply pressure, however, may result in
inaccurate mixture ratio. Additionally, maintenance of the belt
drives and pulleys for the belt drives may cause variations in the
mixture ratio. Further, as pump calibration is critical to
maintaining a desired ration, variations in the calibrations of the
pumps may result in inaccurate mixtures.
[0012] Accordingly, there exists a need for a mixing system that
provides accurate ratios of each component of a mixture.
Additionally, there exists a need for accurate ratios of each
component of a mixture when fluid inlet pressures may vary.
Further, there exists a need for a mixing system that requires a
small amount of space on an ocean rig.
SUMMARY OF INVENTION
[0013] In one aspect, the present invention relates to a mixing
pump having a power cylinder and a second cylinder, wherein one of
the power cylinder and the second cylinder is interchangeable
between single and double acting and wherein a working fluid is
supplied to the power cylinder under pressure.
[0014] In another aspect, the present invention relates to a mixing
pump including a power cylinder, a second cylinder, and a third
cylinder, wherein a working fluid is supplied to the power cylinder
under pressure.
[0015] In another aspect, the present invention relates to a mixing
pump including a first cylinder, a second cylinder, and a piston
assembly. Preferably, a first piston of the piston assembly divides
the first cylinder into a first chamber and a second chamber and a
second piston of the piston assembly divides the second cylinder
into a third chamber and a fourth chamber. Preferably, a
pressurized working fluid is connected to a switching mechanism
wherein the switching mechanism is configured to alternately
communicate the pressurized working fluid between the first and
second chambers of the first cylinder to displace the first piston.
Preferably, a first additive fluid is connected to an inlet of one
of the third and the fourth chambers of the second cylinder,
wherein the pressurized working fluid and the additive fluid are
outputted to a supply tank as the piston assembly reciprocates
within the fist and second cylinders.
[0016] Other aspects and advantages of the invention will be
apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a flow diagram of a mixing system in accordance
with an embodiment of the present invention.
[0018] FIG. 2 is a flow diagram of a mixing system in accordance
with an embodiment of the present invention.
[0019] FIG. 3 is a cross-sectional view of a mixing system in
accordance with an embodiment of the present invention.
[0020] FIG. 4 is a chart of volume ratios of the embodiment shown
in FIG. 3 in an embodiment of the present invention.
DETAILED DESCRIPTION
[0021] In one aspect, embodiments of the present invention relate
to mixing systems that supply a pre-determined ratio of at least
two fluids to a supply tank. In another aspect, embodiments of the
present invention relate to mixing systems that provide three
fluids to a mixing pump that pumps a pre-determined ratio of the
three fluids to a supply tank. In another aspect, embodiments of
the present invention relate to mixing pumps that control a ratio
of components of a mixture being pumped into a supply tank.
[0022] Referring initially to FIG. 1, a flow diagram of a mixing
system 100 and a cross-sectional view of a mixing pump 102 in
accordance with embodiments of the present invention is shown.
Mixing system 100 includes mixing pump 102 and a drive pump 104.
Drive pump 104 may be any device known in the art that supplies a
base working fluid. In this disclosure, the term "base" is used to
describe the fluids from which the final hydraulic fluid is based.
Furthermore, the term "working" is used to describe base fluids
that are used as the working medium to drive mixing pumps (e.g.,
drive pump 102) in accordance with embodiments of the present
invention. Therefore, a single fluid may be used as a base fluid
and as a working fluid in accordance with embodiments of the
present invention. As such, in one embodiment, drive pump 104 may
be a motor-drive pump. Alternatively, in another embodiment, drive
pump 104 may be a tower that supplies pressurized working fluid by
gravity. Mixing system 100 is configured to receive at least two
fluids from individual storage tanks or fluid pipelines. As shown
in FIG. 1, mixing system 100 is configured to receive a base
working fluid and at least one additive fluid (e.g. glycol and/or
control fluid concentrate). While potable water is described as the
working fluid throughout this disclosure, it should be understood
by those having ordinary skill in the art that any fluid may be
used as a base fluid without departing from the scope of the
present invention.
[0023] As shown in cross-sectional view of mixing pump 102 in FIG.
1, mixing pump 102 includes a power cylinder 114 coupled to a
second cylinder 116. Cylinders 114, 116 may be coupled by any
method known in the art, for example, by welding or bolting. A
first piston 120 is disposed inside power cylinder 114 and a second
piston 122 is disposed inside second cylinder 116. A piston rod 126
couples first piston 120 and second piston 122 together. In one
embodiment, piston rod 126 may be integrally formed with first
piston 120 and second piston 122. Alternatively, in another
embodiment, piston rod 126 may be bolted or welded to first piston
120 and second piston 122. Piston rod 126 extends laterally from
power cylinder 114 into second cylinder 116 through an opening in a
first end 128 of power cylinder 114. A seal (not shown) may be
disposed in the opening of first end 128 of power cylinder 114
around piston rod 126 to prevent fluid flow between cylinders 114,
116. Those having ordinary skill in the art will appreciate that
the seals may be formed from any material known in the art, for
example, an elastomer.
[0024] As discussed above, a base fluid and at least one additive
fluid may be combined with mixing system 100. The base fluid and at
least one additive fluid may be any fluids known in the art. For
example, in the embodiment shown in FIG. 1, the base fluid may be
potable water 112. In another embodiment, additive fluids that may
be combined with base fluid include, but are not limited to, glycol
106 and a control system concentrate 108. In another embodiment,
drive pump 104 may be configured to receive potable water 112 and
discharge pressurized water 113 into power cylinder 114. In another
embodiment, drive pump 104 may be a high volume, low pressure water
pump. In another embodiment, glycol 106 may be stored in a tank and
supplied to second cylinder 116 by gravity. Additionally, in
another embodiment, control system concentrate 108 may be stored in
a tank and supplied to second cylinder 116 by gravity. A selector
valve 138 may selectively supply additive fluids, such as control
system concentrate 108 or glycol 106, depending on the preferred
additive fluid to second cylinder 116.
[0025] Referring still to FIG. 1, power cylinder 114 includes an
inlet 160 and an outlet 162 in a first chamber 140 and an inlet 161
and an outlet 163 in a second chamber 142. Similarly, second
cylinder 116 has an inlet 150 and an outlet 152 in a first chamber
144 and an inlet 151 and an outlet 153 in a second chamber 146.
Thus, with two chambers, each cylinder 114, 116 may be single or
double acting. For the purpose of this disclosure, a single-acting
cylinder is one where a single chamber outputs fluid to a holding
tank and a double-acting cylinder is one where both chambers output
fluid to the holding tank. As such, both chambers of a
single-acting cylinder may fill with fluid from an inlet, but only
one of the two chambers will direct fluid to the holding tank when
the piston is reciprocated. The fluid (if present) in the other,
not active, chamber may be vented out back to the supply tank or
any other location. In the embodiment shown in FIG. 1, cylinders
114, 116 are double acting, thus allowing fluids to fill each
chamber 140, 142, 144, and 146 and exit to a holding tank through
outlets 152, 153, 162, and 163. Therefore, those having ordinary
skill in the art will appreciate that the present invention is not
limited to the action (single or double acting) of each
cylinder.
[0026] In the embodiment shown in FIG. 1, a base working fluid
(e.g. potable water 112) may be supplied to drive pump 104. As
such, potable water 112 enters drive pump 104 to become pressurized
water 113, which is pumped into power cylinder 114. A switch valve
132 directs pressurized water 113 into first chamber 140 or second
chamber 142. Switch valve 132 may be controlled by a valve
controller 159. Glycol 106 or control system concentrate 108 may be
fed by gravity into chambers 144, 146 of second cylinder 116.
[0027] In the embodiment shown in FIG. 1, as first chamber 140 of
power cylinder 114 fills with pressurized water 113, first piston
120 moves to the right. As first piston 120 moves to the right,
pressurized water 113 that may be in second chamber 142 of power
cylinder 114 is forced through outlet 163 to a supply tank (not
shown). Simultaneously, piston rod 126 moves second piston 122 of
second cylinder 116 to the right. As second piston 122 moves to the
right, glycol 106 enters through inlet 150 and fills first chamber
144 and glycol 106 in second chamber 146 of second cylinder 116 is
forced out through outlet 152 to the supply tank (not shown).
Switch valve 132 then switches pressurized water 113 flow from
inlet 160 to 161, thereby filling second chamber 142 of power
cylinder 114. Accordingly, first piston 120 moves to the left.
[0028] As first piston 120 moves to the left, pressurized water 113
in first chamber 140 of power cylinder 114 is forced through outlet
162 to the supply tank (not shown). Simultaneously, piston rod 126
moves second piston 122 of second cylinder 116 to the left. As
second piston 122 moves to the left, glycol 106 in first chamber
144 is forced through outlet 152 of second cylinder 116 to the
supply tank (not shown) and glycol 106 enters through inlet 151 and
fills second chamber 146. Check valves 188 may be disposed on the
additive fluid lines entering and exiting second cylinder 116 to
prevent reverse flow of additive fluids 106, 108 therethrough.
Therefore, switch valve 138 may be used to alternately fill first
chamber 140 and second chamber 142 of power cylinder 114 such that
pistons 120 and 122 reciprocate to pump and mix base working fluid
112 and glycol 106 together.
[0029] In another embodiment, if glycol 106 is no longer preferred
in the mixture, selector valve 138 may change additive fluid supply
to second cylinder 116 from glycol 106 to control system
concentrate 108, for example. Additionally, in another embodiment,
selector valve 138 may change additive fluid supply to each chamber
144 and 146 of second cylinder 116, for example, allowing glycol
106 to enter into first chamber 144 and control system concentrate
108 to enter into second chamber 146. Accordingly, the mixing pump
102 performs in the same manner described above. Those having
ordinary skill in the art will appreciate that selector valve 138
may be actuated by any method known in the art, for example,
manually, or electrically.
[0030] Further, in another embodiment, power cylinder 114 may
instead be single acting. In this embodiment, power cylinder 114
may include a biasing mechanism to push against first piston 120.
For example, with a spring disposed within second chamber 142 of
power cylinder 114, pressurized working fluid may fill first
chamber 140, move piston 120 to the right, and compress the spring
disposed within chamber 142. When compressed, the spring may be
used to then push first piston 120 to the left, rather than needing
pressurized working fluid to switch from flowing across inlets 160,
161. Those having ordinary skill in the art will appreciate other
biasing mechanisms, such as elastomer, may be used without
departing from the scope of the present invention. Furthermore, in
such circumstances, second chamber 142 of single acting power
cylinder 114 may be vented to prevent accumulation of pressure
within second chamber 142 as first piston 120 moves. As such, those
having ordinary skill in the art will appreciate that any of the
chambers may be vented when used within a single acting cylinder of
the present invention.
[0031] Referring now to FIG. 2, a flow diagram of a mixing system
200 and a cross-sectional view of a mixing pump 102 in accordance
with embodiments of the present invention is shown. Mixing pump 102
of mixing system 200 in FIG. 2 further includes a third cylinder
118, in addition to power cylinder 114 and second cylinder 116. A
third piston 124 is disposed inside third cylinder 118. Piston rod
126 then couples first piston 120, second piston 122, and third
piston 124 together. Piston rod 126 extends laterally from power
cylinder 114 to third cylinder 118 through an opening in a second
end 130 of power cylinder 114. A seal may be disposed in the
opening of second end 130 of power cylinder 114 around piston rod
126 to prevent fluid flow between cylinders 114, 118.
[0032] As shown in FIG. 2, glycol 106 may be stored in a tank and
supplied to either (or both) chamber 144, 146 of second cylinder
116. Additionally, potable water 112 may also be supplied to either
(or both) chamber 144, 146 of second cylinder 116. Selector valve
138 may be used to selectively supply potable water 112 or glycol
106 to second cylinder 116, depending on an operational
temperature. Further, control system concentrate 108 may be stored
in a tank and supplied to third cylinder 118 by gravity. However,
those having ordinary skill in the art will appreciate that the
present invention is not limited to any particular fluid supplied
to the cylinder in that a base fluid and/or an additive fluid may
be supplied to any of the chambers and cylinders within the mixing
pump of the present invention.
[0033] Referring still to FIG. 2, third cylinder 118 has an inlet
170 and an outlet 171 in a chamber 148. Accordingly, power cylinder
114 and second cylinder 116 are double acting, and third cylinder
118 is single acting. Thus, for third cylinder 118, fluid may only
enter chamber 148. However, as discussed above, those having
ordinary skill in the art will appreciate that the present
invention is not limited to the action of each cylinder. As such,
while third cylinder 118 is shown as a single-acting cylinder
having only one active chamber 148, it should be understood that a
dual-acting cylinder having a second chamber may be used.
Furthermore, as described above in reference to second cylinder
116, potable water 112 may also be supplied to chamber 148 to
accommodate a variety of mixing ratios. Further still, a switching
mechanism may be used to alternately communicate potable water 112
to any chamber of any cylinder on selected (e.g, one of every two,
one of every three, etc.) strokes of piston 120 to accommodate wide
range of mixing ratios.
[0034] As shown in FIG. 2, as first chamber 140 of power cylinder
114 fills with pressurized water 113, third piston 124 will move
simultaneously to the right with first piston 120 and second piston
122. As piston 124 moves to the right, control system concentrate
108, filled in chamber 148 of third cylinder 118, is forced through
outlet 171 and into the supply tank (not shown). When switch valve
132 switches pressure water 113 flow from inlet 160 to 161, thereby
filling second chamber 142 of power cylinder 114, third piston 124
will simultaneously move to the left with first piston 120 and
second piston 122. As piston 124 moves to the left, control system
concentrate 108 enters chamber 148 of third cylinder 118 through
inlet 170.
[0035] In the embodiment shown in FIG. 2, if the operational
temperature changes and glycol 106 is no longer needed in the
mixture, selector valve 138 may change fluid supply to second
cylinder 116 from glycol 106 to potable water 112. Accordingly, the
mixing pump 102 performs in the same manner described above and the
ratio of control system concentrate 108 remains unchanged.
[0036] Referring now to FIG. 3, a cross-sectional view of a mixing
system 300 in accordance with embodiments of the present invention
is shown. Mixing pump 102 includes a power cylinder 114, a second
cylinder 116, and a third cylinder 118 such that each of cylinders
114, 116, and 118 is double acting and has two chambers that may
receive fluid. Power cylinder 114 includes chambers A and B, second
cylinder 116 includes chambers C and D, and third cylinder includes
chambers E and F. During operation, as chamber A of power cylinder
114 fills with fluid, chamber C of second cylinder 116 and chamber
E of third cylinder 118 may fill with fluid and remaining chambers
B, D, and F may expel fluids. Correspondingly, as chamber B of
power cylinder 114 fills with fluid, chamber D of second cylinder
116 and chamber F of third cylinder 118 may fill with fluid and
remaining chambers A, C, and E may expel fluids. In one embodiment,
the full volume ratio of chamber A to chamber B to chamber C to
chamber D to chamber E to chamber F (i.e., A:B:C:D:E:F) is
5:5:1:0.5:2:3. Therefore, chamber C would be five times larger in
volume than chamber A, and chamber E would be two times larger in
volume than chamber A.
[0037] Referring now to FIG. 4, a chart of volume ratios of base
fluid to additive fluid when combined from chambers A, B, C, D, E,
F of a mixing pump 102 (e.g. FIG. 3) in accordance with embodiments
of the present invention is shown. Particularly, in the embodiment
shown in FIG. 3, one base fluid and one additive fluid may be added
to mixing pump 102 to provide a mixture for the supply tank (not
shown). In FIG. 4, the first column provides the chambers of mixing
pump 102 from FIG. 3 that may be filled with a working fluid and
the second column provides the chambers of mixing pump 102 that may
be filled with an additive fluid. Column 3 then provides a ratio of
the working fluid to the additive fluid in a mixture after one full
stroke of the mixing system 300. One full stroke refers to the
pistons of the cylinders moving completely right and then moving
completely left, allowing each chamber A, B, C, D, E, and F to fill
completely with working fluid or additive fluid once. As shown in
column 3 of FIG. 4, mixing system 300 of FIG. 3 allows for a broad
range of ratios between the working fluid and the additive fluid
(e.g. from 30:1 to 1.54:1).
[0038] Those having ordinary skill in the art will appreciate that
the size of the cylinders, the size of the pistons, and the size of
the piston rod may vary without departing from the scope of the
present invention. Specifically, the sizes and volumes of the
cylinders, pistons, and piston rod may be used to vary the ratio of
individual components required for the mixture. For example, in one
embodiment, by increasing the size of chambers E, F in FIG. 3 such
that chamber E is four times larger in volume than chamber A and
chamber F is five times larger in volume than chamber A (i.e., a
mixing pump full volume ratio of 5:5:1:0.5:4:5), the maximum
possible ratio of working fluid to additive fluid may increase to
38:1. In another embodiment, the size of a portion of piston rod
126 coupling first piston 120 to second piston 122 may be changed
with respect to portions coupling first piston 120 to third piston
124. In this embodiment, the changed volume of the portion of
piston rod 126 coupling first piston 120 to second piston 122 may
increase or decrease the displacement volume of chambers A, D such
that the mixing pump full volume ratio may be varied. Thus,
changing the full volume ratio of the chambers with respect to one
another allows for the ratio of the resulting mixture to
change.
[0039] As shown and described with reference to FIGS. 1-3, the
present invention provides a mixing system and a mixing pump that
is powered by pressurized working fluid. The pressurized working
fluid supplied to the power cylinder is used to regulate the amount
of additive fluid that may enter and exit the mixing pump.
Therefore, by regulating the configuration and geometry of the
cylinders of the mixing pump, the ratio of the multiple additive
fluids in the working fluid may be maintained without relying on
multiple pumps and/or a constant water pressure.
[0040] Those having ordinary skill in the art will appreciate that
the present invention is not limited to the use of pistons. For
example, in another embodiment, instead of a piston, a flexible
diaphragm may be used. As pressurized working fluid enters the
chambers of a cylinder, the flexible diaphragm may transfer
pressure from one chamber to another chamber, allowing fluid to
enter and exit the respective chambers. Additionally, in another
embodiment, a plunger pump may be used instead of piston. Thus, the
present invention is not limited by specific means to translate
pressure from one chamber of a cylinder to another.
[0041] Those having ordinary skill in the art will appreciate that
the present invention may be provided with a feedback mechanism. A
feedback mechanism may be used to provide a relative position of a
piston within its corresponding cylinder, thereby providing the
current volumes of the chambers with the cylinder. Common examples
that may be used for a feedback mechanism may be a linear variable
displacement transducer ("LVDT"), a microswitch, or a magnet.
[0042] While embodiments described above refer to a mixing system
and mixing pump with three cylinders (i.e., one power, two additive
cylinders), those having ordinary skill in the art will appreciate
that additional fluids may be combined at differing ratios by
providing additional cylinders and pistons. These additional
pistons may be coupled to the piston rod and powered by a fluid
pressure acting within a power cylinder. For example, in another
embodiment, a fourth cylinder having a fourth piston disposed
therein may be added to the mixing pump. As such, the fourth
cylinder may be attached to the third cylinder with the fourth
piston may be coupled to the third piston through the piston rod.
As the piston rod, and therefore the third piston, moves from the
fluid pressure within the power cylinder, the fourth piston would
correspondingly move within the fourth cylinder, pumping the fluids
supplied to the fourth cylinder to a supply tank.
[0043] Advantageously, the present invention provides a mixing
system with accurate and reliable ratios of components in a
mixture. The present invention provides a mixing system that
requires less space for operation. Further, the present invention
provides a mixing system with fewer pumps and motors, allowing a
mixing pump to be most cost effective.
[0044] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims.
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