U.S. patent application number 15/812234 was filed with the patent office on 2018-03-08 for liquid color closed loop refill method and apparatus.
The applicant listed for this patent is Stephen B. Maguire. Invention is credited to Stephen B. Maguire.
Application Number | 20180066639 15/812234 |
Document ID | / |
Family ID | 1000003001285 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180066639 |
Kind Code |
A1 |
Maguire; Stephen B. |
March 8, 2018 |
LIQUID COLOR CLOSED LOOP REFILL METHOD AND APPARATUS
Abstract
Method and apparatus for furnishing process machines with liquid
color from a supply thereof provides a loop conduit having
respective ends receiving liquid color from the supply and
discharging liquid color back into the supply, pumping liquid color
through the loop conduit and discharging liquid color from the loop
conduit at an intermediate position into a reservoir associated
with a process machine upon liquid color level in the reservoir
being at a low level limit.
Inventors: |
Maguire; Stephen B.; (West
Chester, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Maguire; Stephen B. |
West Chester |
PA |
US |
|
|
Family ID: |
1000003001285 |
Appl. No.: |
15/812234 |
Filed: |
November 14, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14620345 |
Feb 12, 2015 |
9841010 |
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15812234 |
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61939816 |
Feb 14, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 49/20 20130101;
F16K 21/18 20130101; Y10T 137/0324 20150401; Y10T 137/7339
20150401; Y10T 137/469 20150401; Y10T 137/7287 20150401; G05D 9/04
20130101; F04B 23/02 20130101; Y10T 137/86035 20150401; G05D 9/12
20130101; F04B 2201/1201 20130101; Y10T 137/86027 20150401; Y10T
137/2673 20150401; Y10T 137/2698 20150401; Y10T 137/4757 20150401;
Y10T 137/7313 20150401; F04B 49/065 20130101 |
International
Class: |
F04B 23/02 20060101
F04B023/02; G05D 9/12 20060101 G05D009/12; G05D 9/04 20060101
G05D009/04; F16K 21/18 20060101 F16K021/18; F04B 49/20 20060101
F04B049/20; F04B 49/06 20060101 F04B049/06 |
Claims
1. A method for furnishing a plurality of process machines with
liquid color from a supply thereof, comprising: a. providing a loop
conduit having outbound and inbound segments with respective ends
receiving liquid color from the supply and discharging liquid color
back into the supply; b. continuously pumping liquid color through
the loop conduit; c. providing a plurality of liquid color
discharge positions in the outbound segment; d. discharging liquid
color from the loop conduit at one of the liquid color discharge
positions on the outboard segment into a respective reservoir
connected by a supply conduit to a respective process machine upon
liquid color level in the respective reservoir being at a
gravimetrically determined low level limit or upon a detector
connected to the respective process machine signaling the need for
liquid color by the machine.
2. The method of claim 1 further comprising intermittently mixing
liquid color in the supply.
3. The method of claim 1 further comprising continuously mixing
liquid color in the supply.
4. The method of claim 1 further comprising increasing pumping
speed whenever liquid color is being discharged from the loop
conduit into the reservoir.
5. The method of claim 1 further comprising discharging liquid
color from the loop conduit by actuating a valve.
6. The method of claim 5 further comprising sensing weight of the
reservoir and upon sensed weight falling below a preselected value,
actuating the valve to discharge liquid color from the conduit to
replenish the reservoir.
7. The method of claim 1 further comprising sensing weight of the
reservoir and upon sensed weight falling below a preselected value
discharging liquid color from the conduit to replenish the
reservoir.
8. The method of claim 2 further comprising sensing weight of the
reservoir and upon sensed weight falling below a preselected value
discharging liquid color from the conduit to replenish the
reservoir.
9. The method of claim 5 further comprising: a. continuously
sensing weight of the reservoir; b. replenishing the reservoir with
liquid color from the conduit when sensed reservoir weight falls
below a preselected level; and c. halting replenishment of the
reservoir with liquid color from the conduit when sensed reservoir
weight reaches a predetermined level.
10. The method of claim 6 further comprising: a. continuously
sensing weight of the reservoir; b. opening the valve to replenish
the reservoir with liquid color from the conduit when sensed
reservoir weight falls below a preselected level; and c. closing
the valve to halt replenishment of the reservoir with liquid color
from the conduit when sensed reservoir weight reaches a
predetermined level.
11. The method of claim 1 further comprising: a. continuously
sensing weight of the reservoir; b. opening a valve to replenish
the reservoir with liquid color from the conduit when sensed
reservoir weight falls below a preselected level; and c. closing
the valve to halt replenishment of the reservoir with liquid color
from the conduit when sensed reservoir weight reaches a
predetermined level.
12. The method of claim 7 further comprising increasing pumping
speed upon sensed reservoir weight decreasing to within a
preselected amount of the preselected level and decreasing pumping
speed upon sensed reservoir weight increasing to at least the
predetermined level.
13. The method of claim 6 further comprising increasing pumping
speed upon sensed reservoir weight decreasing to within a
preselected amount of the preselected level and decreasing pumping
speed upon sensed reservoir weight increasing to at least the
predetermined level.
14. A method for furnishing process machines with liquid color from
a supply thereof, comprising: a. providing a loop conduit having
respective ends receiving liquid color from the supply and
discharging liquid color back into the supply; b. pumping liquid
color through the loop conduit; c. mixing liquid color in the
supply; d. discharging liquid color from the loop conduit into a
reservoir associated with a process machine by opening at least one
valve in the loop conduit upon the process machine signaling a need
for liquid color; e. halting discharge of liquid color from the
loop conduit; f. increasing pumping speed upon sensed reservoir
weight decreasing to within a preselected amount of the preselected
level and decreasing pumping speed upon sensed reservoir weight
increasing to at least the predetermined level.
15. Apparatus for furnishing process machines with liquid color
from a supply thereof, comprising: a. a loop conduit for carrying
liquid color from the supply to the process machine(s) and back to
the supply; b. a pump for circulating liquid color around the loop
conduit; c. a detector for sensing when additional liquid color is
needed by an associated process machine; d. a valve in the loop
conduit for diverting liquid color from the loop to the associated
process machine upon the detector sensing the need for
replenishment.
16. Apparatus of claim 15 further comprising: a. a reservoir
associated with each process machine for temporarily storing liquid
color received from the loop conduit until needed by the process
machine; and b. wherein the detector comprises a load cell for
detecting the weight of the reservoir and hence the amount of
liquid color therein.
17. Apparatus of claim 16 further comprising a solenoid for
actuating the valve.
18. Apparatus of claim 17 wherein segments of the loop conduit are
structurally mounted adjacent to one another such that liquid color
travels in opposite directions in the mounted segments and the
valve is in one of the segments.
19. A method for furnishing process machines with liquid color from
a supply thereof, comprising: a. providing a loop conduit having
respective ends receiving liquid color from a supply and
discharging liquid color back into the supply; b. pumping liquid
color through the loop conduit; c. discharging liquid color from
the loop conduit at an intermediate position thereon to a process
machine upon liquid color level for the process machine being at a
low level limit.
20. The method of claim 19 further comprising increasing pumping
speed upon liquid color level for the process machine being at the
low level limit.
21. A method for furnishing a plurality of process machines with
liquid color from a supply thereof, consisting of: a. providing a
loop conduit having outbound and inbound segments with respective
ends receiving liquid color from the supply and discharging liquid
color back into the supply; b. continuously pumping liquid color
through the loop conduit; c. providing a plurality of liquid color
discharge positions in the outbound segment; d. discharging liquid
color from the loop conduit at one of the liquid color discharge
positions on the outboard segment into a respective reservoir
connected by a supply conduit to a respective process machine upon
liquid color level in the respective reservoir being at a
gravimetrically determined low level limit or upon a detector
connected to the respective process machine signaling the need for
liquid color by the machine.
22. Apparatus for furnishing process machines with liquid color
from a supply thereof, consisting of: a. a loop conduit for
carrying liquid color from the supply to the process machine(s) and
back to the supply; b. a pump for circulating liquid color around
the loop conduit; c. a detector for sensing when additional liquid
color is needed by an associated process machine; d. a valve in the
loop conduit for diverting liquid color from the loop to the
associated process machine upon the detector sensing the need for
replenishment.
23. A method for furnishing process machines with liquid color from
a supply thereof, consisting of: a. providing a loop conduit having
respective ends receiving liquid color from a supply and
discharging liquid color back into the supply; b. pumping liquid
color through the loop conduit; c. discharging liquid color from
the loop conduit at an intermediate position thereon to a process
machine upon liquid color level for the process machine being at a
low level limit.
24. Apparatus for furnishing process machines with liquid color
from a supply thereof, consisting essentially of: a. a loop conduit
for carrying liquid color from the supply to the process machine(s)
and back to the supply; b. a pump for circulating liquid color
around the loop conduit; c. a detector for sensing when additional
liquid color is needed by an associated process machine; d. a valve
in the loop conduit for diverting liquid color from the loop to the
associated process machine upon the detector sensing the need for
replenishment.
25. A method for furnishing process machines with liquid color from
a supply thereof, consisting essentially of: a. providing a loop
conduit having respective ends receiving liquid color from a supply
and discharging liquid color back into the supply; b. pumping
liquid color through the loop conduit; c. discharging liquid color
from the loop conduit at an intermediate position thereon to a
process machine upon liquid color level for the process machine
being at a low level limit.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This patent application is a 35 USC 120 continuation
application of U.S. Ser. No. 14/620,345, now published as United
States patent publication U.S. 2015-0233369 A1, filed 12 Feb. 2015
in the name of Stephen B. Maguire and entitled "Method and
Apparatus for Closed Loop Automatic Refill of Liquid Color," which
in turn claimed the benefit of the priority of U.S. provisional
application Ser. No. 61/939,816 filed 14 Feb. 2014 in the name of
Stephen B. Maguire and entitled "Liquid Color Closed Loop Automatic
Refill System"; the priority was claimed under 35 USC 119 and 35
USC 120; such priority is also claimed for this application.
STATEMENT REGARDING FEDERAL FINANCING RESPECTING THIS INVENTION
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] Liquid color is metered from containers. When the liquid
runs out and a process machine, namely an injection molding machine
or extruder, is operating producing plastic parts, there is a time
period where no color is being metered, and production parts must
be scrapped because they do not get the required color. One
solution is to alarm when color level is low, and change the liquid
color container before the liquid color runs out. However, this
results in the remaining liquid color being wasted, or a mess due
to spillage, when transferring the remaining liquid color into the
new container.
[0004] A better solution is to simply refill the container before
the liquid color runs out. Currently available systems for doing
this involve a level sensor to detect low level in the primary
container, and then a reserve container and pump standing by for
refilling the primary container.
[0005] The reserve container may be small, but preferably is large
enough to last for many weeks. Two thousand pound capacity totes
are standard in the industry.
[0006] This reserve container may be very close, or may be located
at some distance. In either case a pump is required for the reserve
container for transferring the liquid color into the primary
container.
[0007] Factories always have many process machines. Each requires
its own primary supply of color, and its own metering pump. In
current systems if, for example, 5 process machines are running and
automatic refill of these containers is desired, then each process
machine requires its own "reserve" container and a reserve pump as
well. This need for 5 reserve containers and 5 pumps is still
present even if all process machines are running the same
color.
SUMMARY OF THE INVENTION
[0008] When multiple process machines are running the same color, a
more efficient system as provided by the instant invention is to
have one large reserve container with a pump to resupply all
primary containers.
[0009] That is how the system of this invention works. One large
reserve container is preferably used to refill each of the primary
containers when any one of the primary containers runs low on
liquid color.
[0010] As a further refinement, this invention preferably also
incorporates a closed loop system to supply liquid color to all of
the process machines. Liquid is preferably continuously pumped out
through a piping system that reaches all of the process machines
and then returns to the reserve container. This assures a constant
supply of "fresh" liquid color, with no risk of the liquid color
settling or separating in the liquid color supply lines. (Settling
can occur when liquid color heavily loaded with pigment is left
sitting in the liquid color supply conduit.) As an added benefit,
this continuous flow also assures continuous turnover of liquid
color and mixing of the liquid color in the reserve container.
[0011] When a primary container requires liquid color, the
invention preferably uses a diverter valve to divert the liquid
color flow from the circulation loop into the selected primary
container. As an additional feature, to allow refill to occur as
rapidly as possible, the invention preferably increases the pump
rate of the circulation pump to its maximum. When not refilling a
container the recirculation pump rate is slowed to a rate that is
reasonable and that conserves energy, or in the most preferred
practice of the invention, conserves compressed air that is
preferably used to drive the pump.
[0012] As an added feature of the invention, metering systems, with
one located at each process machine, use load cells to control
metering gravimetrically. The load cells are also available to
signal the proper time for refill to occur. Level sensors can be
used in place of the load cells.
[0013] In one of its aspects, this invention provides a method for
furnishing process machines with liquid color from a supply thereof
where the method preferably commences with providing a loop conduit
having respective ends receiving liquid color from the supply and
discharging liquid color into the supply. The method preferably
proceeds with pumping liquid color through the loop conduit. The
method then discharges liquid color from the loop conduit at an
intermediate position thereon into a reservoir associated with a
process machine upon the process machine signaling a need for
liquid color.
[0014] The method may further include providing at least one valve
in the conduit for discharging liquid color therefrom and
discharging liquid color from the loop conduit by actuating the
valve.
[0015] In another one of its aspects, this invention preferably
provides apparatus for furnishing process machines with liquid
color where the apparatus preferably includes a supply of liquid
color, a loop conduit for carrying liquid color with the loop
conduit preferably running from the supply to the process machines
and back to the supply, a pump for circulating liquid color around
the loop, a detector for sensing when liquid color is needed by an
associated process machine, and a valve in the loop for diverting
liquid color from the loop to the associated process machine upon
the detector sensing the need for replenishment. In an apparatus
aspect of the invention, a solenoid is preferably provided for
actuating the valve. Furthermore in an apparatus aspect of the
invention, segments of the loop conduit are preferably structurally
mounted adjacent to one another such that liquid color travels in
opposite directions in the mounted segments and the valve is in one
of the segments.
[0016] In still another one of its aspects, this invention provides
a method for furnishing process machines such as injection molding
presses, compression molding presses and extruders, and ancillary
machines such as receivers and gravimetric blenders, with liquid
color from a supply of liquid color. In one of these method
aspects, the invention proceeds by providing a loop conduit having
respective ends receiving liquid color from the supply and
discharging liquid color back into the supply, and discharging
liquid color from the conduit loop at an intermediate position
thereon into a reservoir associated with a process machine upon the
process machine signaling a need for liquid color.
[0017] The method may further include intermittently mixing liquid
color in the supply or continuously mixing liquid color in the
supply.
[0018] In yet another one of its aspects, the method may further
include increasing pumping speed whenever liquid color is being
discharged from the loop conduit into a reservoir associated with a
process machine. The method may further include providing at least
one diverter valve in the conduit for discharging liquid color from
the conduit, and specifically discharging the liquid color from the
liquid conduit by actuating the diverter valve.
[0019] In still another aspect of the invention, the invention
embraces the steps of sensing weight of the reservoir and upon
sensed weight of the reservoir falling below a pre-selected value,
actuating a diverter valve to discharge liquid color from the
conduit to replenish the reservoir.
[0020] The method may further embrace sensing the weight of the
reservoir and upon sensed reservoir weight falling below a
pre-selected value, discharging liquid color from the conduit to
replenish the reservoir.
[0021] The method may further embrace the step of increasing
pumping speed upon sensed reservoir weight decreasing to within a
pre-selected amount of the pre-selected level and decreasing
pumping speed upon sensed reservoir weight increasing to at least
the pre-determined level.
[0022] In another one of its aspects, this invention provides a
method for furnishing process machines with liquid color from a
supply by providing a loop conduit having respective ends receiving
liquid color from the supply and discharging liquid color into the
supply, pumping liquid color through the loop conduit, mixing
liquid color in the supply, providing at least one valve in the
conduit for discharging liquid color therefrom, discharging liquid
color from the loop conduit into a reservoir associated with the
process machine by opening a valve in the loop conduit upon the
process machine signaling a need for liquid color, halting
discharge of liquid color from the loop conduit, and increasing
pumping speed upon sensed reservoir weight decreasing to within a
pre-selected amount of the pre-selected level but decreasing
pumping speed upon sensed reservoir weight increasing to at least
the pre-determined level.
[0023] In still yet another one of its aspects, this invention
provides apparatus for furnishing process machines with liquid
color where the apparatus includes a loop conduit for carrying
liquid color running from the supply to the process machines and
back to the supply, a pump for circulating liquid color around the
loop, a detector for sensing when additional liquid color is needed
by an associated process machine, and a valve in the loop for
diverting liquid color from the loop to the associated process
machine upon the detector sensing the need for replenishment. The
apparatus may further include a reservoir associated with each
process machine for temporarily storing liquid color received from
the loop conduit until needed by the process machine and a load
cell for detecting the weight of the reservoir and hence the amount
of liquid color therein.
[0024] The apparatus may further preferably include a solenoid for
actuating the valve.
[0025] In one more aspect of the apparatus, segments of the loop
conduit may be structurally mounted adjacent to one another such
that liquid color travels at opposite directions in the mounted
segments and the valve is in one of those segments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic representation of apparatus embodying
the method for practicing aspects of the invention.
[0027] FIG. 2 is an artist's rendition, in isometric form, of
apparatus manifesting aspects of the invention and showing a number
of process machines receiving liquid color in accordance with the
invention.
[0028] FIG. 3 is an isometric drawing of a portion of a loop
conduit of the invention, with a diverter valve positioned therein,
with the conduit and the diverter valve mounted on a common support
structure.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring to the drawings in general and to FIG. 1 in
particular, apparatus embodying the invention and suitable for
practice the method aspects of the invention is designated
generally 10 and includes a loop conduit 12 leading from a liquid
color supply 16 to a pump 14. From the pump 14, the loop conduit 12
proceeds to a diverter valve 18 and from diverter valve 18 on
around to the liquid color supply 16 to deposit liquid color that
has not been diverted by valve 18 back into liquid color supply 16.
Diverter valve 18, when actuated, diverts liquid color from loop
conduit 12 down through supply conduit 28 into a reservoir or
holding tank 20.
[0030] A load cell 22 senses the weight of reservoir or holding
tank 20 and thereby senses the weight of liquid color within
reservoir or holding tank 20. Load cell 22 may be supported by
structure resting on a floor 26. It is to be understood that any
suitable structure may be used for supporting load cell 22 in a
position to sense the weight of reservoir or holding tank 20.
[0031] An agitator or mixer 24 is provided for mixing liquid color
within a supply 16. Agitator or mixer 24 is depicted only
schematically. Agitator or mixer 24 is conventionally
motor-driven.
[0032] Diverter valve 18 is preferably actuated by solenoid 30.
Upon actuation of valve 18 by solenoid 30, liquid color flowing
through loop conduit 12 is diverted to flow down through supply
conduit 28 into reservoir or holding tank 20, rather than flowing
around the remainder of loop conduit 12 and back into liquid color
supply 16.
[0033] Solenoid 30 actuates diverter valve 18 to open diverter
valve 18 to permit flow of liquid color through supply conduit 28
into reservoir 20 upon sensed weight of reservoir 20 being low,
indicating a low level of liquid color within reservoir 20. Weight
sensing is performed by load cell 22. Once load cell 22, which
continuously senses weight of reservoir or holding tank 20, senses
that reservoir or holding tank 20 is beginning to approach its
maximum capacity for liquid color, a signal is sent to solenoid 30.
The signal de-actuates diverter valve 18 whereupon no liquid color
is permitted to flow into supply conduit 28, but rather liquid
color continues to flow through valve 18 around loop conduit 12 and
back to liquid color supply 16.
[0034] The invention further embraces regulation of the speed of
pump 14. Desirably the speed of pump 14 is increased upon the
sensed weight of reservoir 20 decreasing to within a pre-selected
amount of a pre-selected low level, but speed of pump 14 is
decreased upon the sensed weight of reservoir 20 increasing to at
least a pre-determined high level.
[0035] The invention further embraces regulation of the mixing or
agitation provided by agitator/mixer 24 for liquid color in liquid
color supply 16. A feed line 38 leads from reservoir or holding
tank 20 to the associated process machine to supply liquid color to
the process machine, as indicated by the arrow in FIG. 1.
[0036] Referring now to FIG. 2 which is an artist's rendition of
the manner in which the invention and apparatus embodying the
invention might be installed in a plastic injection molding
facility, apparatus in accordance with the invention is designated
generally 10 with the loop conduit designated generally 12 and a
pump designated generally 14 being associated with a reservoir or
holding tank 20, all as illustrated in FIG. 2. Valves 18 are
provided for diverting liquid color from loop conduit 12 into
individual reserve or holding tanks 20 with one such reserve or
holding tank 20 being associated with each one of the process
machines 34, which in the drawing are illustrated as injection
molding presses. Valves 18 are not visible in FIG. 2.
[0037] Liquid color is delivered from individual reservoirs or
holding tanks 20 to the process machines 34 by feed line 38. There
is one feed line 38 for each reservoir/holding tank 20-process
machine 34 combination as illustrated in FIG. 2. Weight of each
reservoir or holding tank 20 is measured by an associated load cell
22 located preferably below reservoir or holding tank 20. There is
preferably an individual load cell 22 for each reservoir or holding
tank 20. Load cells 22 are supported by suitable structure, which
also supports the associated reservoir or holding tank 20 and which
preferably rests on a floor 26 of the facility in which process
machines 34 are located.
[0038] An agitator or mixer is provided for liquid color residing
in liquid color supply 16. Hoppers 36 associated with each one of
process machines 34, in this case injection molding presses, retain
granular resin until the granular resin is needed by the molding
machine for the manufacture of plastic parts.
[0039] Each reservoir/holding tank 20 is connected to loop conduit
12 by a supply conduit 28 leading downwardly from a diverter valve,
not shown in FIG. 2, that when actuated by a solenoid, not shown in
FIG. 2, diverts liquid color from loop conduit 12 downwardly
through supply conduit 28 into reservoir or holding tank 20.
[0040] A feed line 38 is provided for each of the reservoir/holding
tank-process machine combinations as illustrated in FIG. 2.
[0041] A controller 32 is provided for each reservoir or holding
tank 20. Controller 32 actuates solenoid 30 thereby to open
diverter valve 18 and permit downward flow of liquid color, under
pressure, from loop conduit 12 into reservoir or holding tank
20.
[0042] FIG. 3 illustrates a mounting block/diverter valve/loop
conduit segment assembly, one of which is provided for each reserve
holding tank 20. Mounting block 44 is mounted on a framework 46
that is associated with and supports reservoir/holding tank 20,
load cell 22 and solenoid 30. Framework 46 is illustrated and
designated so in FIG. 2, but is not illustrated in FIG. 3.
[0043] Mounting block 44 supports outbound segment 40 and inbound
segment 42 of loop conduit 12. A diverter valve 18 is provided in
the outbound segment of loop conduit 40 and is actuated by solenoid
30. Upon energizing solenoid 30 and consequent activation of
diverter valve 18, liquid color flowing in the outbound segment 40
of loop conduit 12 is diverted downwardly by valve 18 and flows
through supply conduit 28 into a particular reservoir or holding
tank with which diverter valve 18 and supply conduit 28 are
associated. Arrows A and B in FIG. 3 denote the direction of flow
of liquid color with liquid color flowing outwardly as indicated by
arrow A through outbound segment 40 of loop conduit 12 and liquid
color returning to supply 16 through inbound segment 42 of loop
conduit 12 as indicated by arrow B.
[0044] During operation, liquid color is desirably pumped
continuously by pump 14 out of liquid color supply 16 through loop
conduit 12. With loop conduit 12 being a "continuous" conduit, loop
conduit 12 reaches all of process machines 34, albeit indirectly,
through supply conduits 28 and feed lines 38, with loop conduit 12
then returning to liquid color supply 16. This assures a constant
supply of "fresh" liquid color with no risk of the liquid color
settling or separating in the liquid color supply line, namely loop
conduit 12. As an additional benefit, this continuous flow through
loop conduit 12 assures continuous turnover of liquid color and
mixing of the liquid color in liquid color supply 16.
[0045] When a reserve or holding tank 20 requires liquid color,
diverter valve 18 is actuated to divert liquid color from loop
conduit 12, specifically from the outbound segment 40 of loop
conduit 12, into the associated reservoir or holding tank 20.
Preferably, when a reservoir or holding tank 20 requires additional
liquid color, the speed of pump 14 is increased to drive liquid
color through loop conduit 12 faster and at higher pressure,
thereby to minimize the time required for liquid color
replenishment into reservoir or holding tank 20. When not refilling
a reservoir or holding tank 20, pump 14 is preferably slowed to a
rate that is reasonable and conserves energy, while continuing to
circulate liquid color around loop conduit 12.
[0046] The metering system, namely the solenoid 30 and controller
32 associated with each reservoir or holding tank 20 uses a load
cell 22 to control the metering of liquid color into each reservoir
or holding tank 20 gravimetrically. Load cell 20 additionally
signals the proper time for refill to occur, namely when the amount
of liquid color in reservoir or holding tank 20 is excessively low
and there is risk that there will be insufficient liquid color
flowing through feed line 38 to satisfy the needs of process
machine 34. While use of load cells is preferable, level sensors in
reserve or holding tank 20 may also be used in place of load
cells.
[0047] In another aspect of the invention, a detector may be
provided associated with a process machine 34 to indicate when
liquid color is needed by that associated process machine. The
detector then provides signal to the controller 32 which actuates
solenoid 30 to move diverter valve 18 so that liquid color is
supplied through supply conduit 28 to reservoir/holding tank 20.
Desirably, a signal is also provided at that time to pump 14 to
drive pump 14 at its maximum speed, to provide liquid color at high
pressure thereby quickly filling the associated reserve or holding
tank 20 and replenishing the liquid color needed by the associated
process machine 34.
[0048] As illustrated in FIG. 3, liquid color preferably moves in
opposite directions with respect to mounting block 44, thereby
balancing any stresses on mounting block 44 resulting from the
dynamic flow of liquid color in directions A and B in FIG. 3.
Additionally, pumping speed of pump 14 is desirably increased upon
sensed weight of a reservoir or holding tank 20 decreasing to
within a pre-selected amount of a pre-selected level, while
decreasing pumping speed upon the sensed reservoir weight
increasing to at least the pre-determined level as a result of the
reservoir or holding tank 20 being filled with liquid color to a
pre-determined level.
[0049] As discussed above and from the foregoing description of the
exemplary embodiments of the invention, it will be readily apparent
to those skilled in the art to which the invention pertains that
the principles and particularly the structures disclosed herein and
the methods of use thereof can be used for applications other than
those specifically mentioned. All such applications of the
invention are intended to be covered by the appended claims unless
expressly excluded therefrom.
[0050] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics of
the invention. The disclosed embodiments are therefore to be
considered in all respects as illustrative and not restrictive with
the scope of the invention being indicated by the appended claims
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are
therefore intended to be embraced therein.
[0051] As used in the claims herein, the term "comprising" means
"including" while the term "consisting of" means "including so much
and no more" and the term "consisting essentially of" means
including the recited elements and those minor accessories required
and known to be used in the art to facilitate the invention as
claimed. The scope of the invention is, therefore, indicated by the
appended claims rather than by the foregoing description and all
changes which come within the range of equivalency of the claims
are to be considered to be embraced within the scope of the
claims.
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