U.S. patent application number 11/455003 was filed with the patent office on 2007-12-20 for multiple pusher liquid color pump.
Invention is credited to Stephen B. Maguire.
Application Number | 20070292288 11/455003 |
Document ID | / |
Family ID | 38861751 |
Filed Date | 2007-12-20 |
United States Patent
Application |
20070292288 |
Kind Code |
A1 |
Maguire; Stephen B. |
December 20, 2007 |
Multiple pusher liquid color pump
Abstract
A liquid color pumping includes a housing, a plurality of
pushers within the housing, a deformable tube for transporting
liquid color from the supply thereof to where the liquid color will
be used with the tube being positionably removable in the housing
at a location at which of the pushers when displaced squeeze the
tube positioning of the pushers resulting in the pushers serially
contacting the tube when displaced and the controller repeated
actuating the pushers in sequence to draw liquid color into the
pumping zone and then to force liquid color out of the pumping zone
through the tube at increased pressure.
Inventors: |
Maguire; Stephen B.; (Glen
Mills, PA) |
Correspondence
Address: |
CHARLES N. QUINN;FOX ROTHSCHILD LLP
2000 MARKET STREET, 10TH FLOOR
PHILADELPHIA
PA
19103
US
|
Family ID: |
38861751 |
Appl. No.: |
11/455003 |
Filed: |
June 16, 2006 |
Current U.S.
Class: |
417/474 |
Current CPC
Class: |
F04B 43/082
20130101 |
Class at
Publication: |
417/474 |
International
Class: |
F04B 43/08 20060101
F04B043/08 |
Claims
1. A pump for liquid color, comprising: a) a housing; b) a
plurality of pushers within the housing; c) a deformable tube for
transporting liquid color from a supply thereof to where the liquid
color will be used; d) the tube being insertable into the housing
and positionable to a location therein at which at least one of
each of the pushers when displaced squeezes the tube against a
stop; and e) a controller for actuating the pushers in sequence
whereby the pusher which upon displacement squeezes the tube
against a stop thereby forces at least a portion of liquid color
through the tube towards the position at which the liquid color
will be used.
2. The pump of claim 2 where the controller repeatedly actuates the
pushers.
3. A pump for liquid color, comprising: a) a housing; b) a pusher
within the housing; c) a deformable tube for transporting liquid
color from a supply thereof to where the liquid color will be used;
d) the tube being removably positionable within the housing to a
location at which the pusher when displaced squeezes the tube; and
e) a controller for actuating the pusher whereby upon pusher
displacement squeezing the tube at least a portion of the liquid
color is forced through the tube and out of the pump.
4. The pump of claim 4 in which the controller repeatedly actuates
the pusher.
5. A pump for liquid color, comprising: a) a housing; b) three
pushers within the housing, positioned side by side respecting one
another; c) a compressible tube for transporting liquid color from
a supply thereof to where the liquid color will be used; d) the
tube being insertable into the housing to a position at which each
of the pushers when displaced squeeze the tube against the housing
interior, with the side by side positioning of the pushers
resulting in the pushers serially contacting the tube when
displaced; and e) a controller for repeatedly actuating the pushers
in sequence whereby a first pusher is displaced to squeeze the tube
closed while a second and a third pusher are not displaced, thereby
permitting liquid color to flow through the tube from the supply to
a first position of tube closure, then the second pusher is
displaced to squeeze the tube closed and trap liquid color in the
tube between the first position of tube closure and a second
position of tube closure, then the first pusher is permitted to
return to its undisplaced position thereby permitting liquid color
to flow through the tube past the first position of tube closure
and the third pusher is displaced to squeeze the tube and thereby
force at least a portion of the trapped liquid color through the
tube past the first position of tube closure.
6. A pump for liquid color, comprising: a) a housing; b) a
plurality of pushers within the housing; and c) a controller for
actuating the pushers in sequence whereby a pusher upon
displacement squeezes a deformable tube thereby forcing at least a
portion of liquid color through the tube towards a location at
which the liquid color will be used.
7. A method for pumping liquid color, comprising repeatedly
actuating three pushers, positioned side by side respecting one
another, in sequence whereby a first pusher is displaced to squeeze
a compressible tube, for transporting liquid color from a supply
thereof to where the liquid color will be used, into a closed
disposition while a second and a third pusher are not displaced,
thereby permitting liquid color to flow through the tube from the
supply to a first position of tube closure, then the second pusher
is displaced to squeeze the tube closed and trap liquid color in
the tube between the first position of tube closure and a second
position of tube closure, then the first pusher is permitted to
return to its undisplaced position thereby permitting liquid color
to flow through the tube past the first position of tube closure
and the third pusher is displaced to squeeze the tube and thereby
force at least a portion of the trapped liquid color through the
tube past the first position of tube closure.
8. The method of claim 7 further comprising removably positioning
the compressible tube within a pusher housing to a location at
which a displaced pusher squeezes the tube.
9. A method for pumping liquid color, comprising: a) repeatedly
actuating three pushers, positioned side by side respecting one
another, in sequence by, i) displacing a first pusher to squeeze a
compressible tube, for transporting liquid color from a supply
thereof to where the liquid color will be used, into a closed
disposition, and ii) retaining a second and a third pusher from
displacement, iii) thereby permitting liquid color to flow through
the tube from the supply to a first position of tube closure, iv)
displacing the second pusher to squeeze the tube closed and trap
liquid color in the tube between the first position of tube closure
and a second position of tube closure; and v) returning the first
pusher to its undisplaced position; vi) thereby permitting liquid
color to flow through the tube past the first position of tube
closure; and vii) displacing the third pusher to squeeze the tube
and thereby force at least a portion of the trapped liquid color
through the tube past the first position of tube closure.
10. The method of claim 7 further comprising removably positioning
the compressible tube within a pusher housing to a location at
which a displaced pusher squeezes the tube.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This patent application discloses subject matter in common
with U.S. patent application Ser. No. ______ entitled "Liquid Color
Gravimetric Metering Apparatus and Methods", filed concurrently
herewith in the name of Stephen B. Maguire.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to processing of plastic
resin material for fabrication into finished plastic parts and more
particularly to methods and apparatus for pumping liquid color
material used to impart a desired color to the finished plastic
parts.
[0004] 2. Description of the Prior Art
[0005] Color is imparted to finished plastic parts by adding a
coloring agent, either liquid color material or solid color
pellets, to plastic resin material as it is being fabricated into
finished plastic parts. The liquid color or the colored pellets
control the color of the finished plastic parts. Depending on
whether liquid color or solid colored pellets is used, the position
at which the coloring agent is added to the plastic resin material
during the part fabrication process may change.
[0006] Pumps for liquid color are known. Liquid color diaphragm
pumping apparatus is disclosed in pending U.S. patent application
Ser. No. 10/066,338, published as United States patent publication
2003-0142580, and in pending U.S. patent application Ser. No.
10/856,422, published as United States patent publication
2005-0052945.
[0007] Additionally, peristaltic pumps are commonly used for
pumping liquid color because all of the liquid color remains in the
peristaltic pump tubing, at all times. As a result, when changing
colors there is no contamination of the liquid color and no clean
up required. When using a peristaltic pump, the only thing required
to change colors is to change the tube in the peristaltic pump.
However, peristaltic pumps, with these advantages, tend to be
unreliable and are expensive.
SUMMARY OF THE INVENTION
[0008] The multiple pusher liquid color pump of this invention in
its preferred embodiment uses three pneumatic cylinder driven
pushers and three solenoids to operate those pneumatic cylinders in
a carefully selected sequence of on and off pulses. When operating
the pump, a deformable tube is placed below the pushers. The
pushers are desirably positioned side by side in a housing and are
attached to the ends of pusher rods connected to the pneumatic
cylinders. These desirably plastic pushers periodically press on
the tube, which is in front of the pushers, thereby squeezing and
compressing the tube against a preferably flat surface.
[0009] The three pushers are preferably aligned and adjacent one to
another. As a result, in the course of one sequence of pusher
operations, the first and second pushers serve as check valves,
compressing the tube and thereby shutting off flow through the tube
when either of these pushers is activated. Then, when activated and
advanced, the center pusher squeezes the tube to displace liquid
color forward. When retracted, the center pusher permits the tube
to relax. This serves to suck in liquid color from the liquid color
supply, for subsequent additional pumping. The sequence is
repeated, rapidly, to provide the desired flow of liquid color
material.
[0010] This pump has many of the advantages of peristaltic pumps,
but is simpler and costs considerably less. This pump does not
include a drive motor, has no bearings and does not include any DC
drive circuitry. The solenoids are preferably driven by simple
on/off signals preferably from a simple, low cost, computerized
control. Variable output of the pump is achieved by regulating the
timing of the pulse sequences, i.e., performing the sequences
faster or slower. Like a peristaltic pump, use of different
diameter tubes produces different pump ranges for output of liquid
color.
[0011] Accordingly, in one of its aspects this invention provides a
pump for liquid color used in fabrication of plastic parts by
molding or extrusion, where the pump preferably includes a housing,
pushers, desirably three, within the housing, with the pushers
preferably being positioned side by side respecting one another, a
compressible tube for transporting liquid color from a supply
thereof to where the liquid color is to be used, with the tube
preferably being removably insertable into the housing to a
position at which each of the pushers, when displaced, squeezes the
tube against structure connected to or forming a part of the
housing, with the side by side positioning of the pushers resulting
in the pushers, upon appropriate actuation, contacting and
squeezing the tube in a desired, preselected sequence of
operations.
[0012] In this aspect, the invention preferably further includes a
controller for repeatedly actuating the pushers in sequence whereby
a first pusher is preferably displaced to squeeze the tube closed
while the second pusher and the third pusher are not displaced,
thereby permitting liquid color to flow through the tube from the
supply to a first position of tube closure, preferably then the
second pusher is preferably displaced to squeeze the tube closed
and trap liquid color in the tube between the first position of
tube closure and a second position of tube closure, and preferably
then the first pusher is preferably permitted to return to its
undisplaced position thereby permitting liquid color to flow
through the tube past the first position of tube closure and
preferably a third pusher is displaced preferably to squeeze the
tube and thereby force at least a portion of the trapped liquid
color through the tube past the first position of tube closure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a front elevation of a multiple pusher liquid
color pump of this invention, for use in practicing the method
aspects of this invention.
[0014] FIG. 2 is a broken front elevation of the lower portion of
the pump illustrated in FIG. 1, with a liquid color delivery tube
removed from the pump housing and shown outside the pump
housing.
[0015] FIGS. 3A through 3F are schematic depictions of three
pushers, illustrated in FIGS. 1 and 2, forming portions of the
pump.
[0016] FIG. 3A depicts the pushers at an initial position at which
all three pushers are retracted and are ready to begin one cycle of
pusher movement for pumping liquid color.
[0017] FIG. 3B depicts the pushers at positions at which a first
pusher has advanced to squeeze the liquid color supply tube closed,
while the second and third pushers have not been displaced, thereby
permitting liquid color to flow through the squeezable liquid color
supply tube from the supply to a first position of tube
closure.
[0018] FIG. 3C depicts the pushers at positions with a second
pusher having additionally been displaced to squeeze the liquid
color supply tube closed and thereby trap liquid color in the tube
between the first position of tube closure defined by the first
pusher and a second position of tube closure defined by the second
pusher.
[0019] FIG. 3D depicts the pushers at positions at which the first
pusher has retracted, the second pusher remains in place to keep
the liquid color supply tube closed at the second position of tube
closure, and a third, center pusher has been displaced to squeeze
the liquid color supply tube and thereby forcedly squeeze some of
the trapped liquid color through the tube past the first position
of tube closure thereby supplying liquid color to a plastic resin
processing machine.
[0020] FIG. 3E depicts the pushers at positions at which the second
pusher remains displaced to continue squeezing the liquid color
supply tube closed while the third pusher has completed travel
towards the liquid color supply tube thereby completing squeezing
of the liquid color supply tube and forcing substantially all of
the liquid color which had been trapped within the liquid color
supply tube downstream of the seal position of tube closure out of
the liquid color tube towards a plastic resin processing machine
for consumption of the liquid color.
[0021] FIG. 3F depicts the pushers at positions at which the second
and third pushers have retracted, the first pusher has advanced to
squeeze the liquid color supply tube closed at the first position
of tube closure thereby permitting liquid color to flow into the
tube from the supply to the first position of tube closure
whereupon the cycle of pusher movement for supplying liquid color
through the liquid color supply tube to a plastic resin process
machine may repeat.
DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE KNOWN FOR
PRACTICE OF THE INVENTION
[0022] Referring to FIG. 1 where triple pusher pump 16 is
illustrated with the front panel of the pump housing removed in
order that the interior components of triple pusher pump 16 may be
viewed, pusher pump 16 includes three pushers, designated 28, 30,
32 respectively. Pushers 28, 30, 32 act against and squeeze liquid
color supply line 22 in an ordered sequence thereby to control flow
of liquid color through supply line 22 and to pump liquid color to
a plastic resin process machine such as an extruder or an injection
molding press via liquid color supply line 22. Each of first,
second and third pushers 28, 30, 32 is connected to and actuated by
a piston-cylinder combination, where first, second and third
piston-cylinder combinations have been designated 34, 36, 38
respectively as being associated with first, second and third
pushers 28, 30 and 32.
[0023] First piston-cylinder combination 34 has been shown with the
exterior of the cylinder portion of the combination cut away to
reveal the inner workings of piston-cylinder combination 34. As
visible in FIG. 1, piston-cylinder combination 34 includes a
cylinder designated 56 and a piston 58, where piston 58 is in a
form of a relatively flat plate.
[0024] Piston cylinder combination 34 further includes a piston
return spring 60, which is preferably of spiral configuration and
slidably contacts the curved interior of cylinder 56, serving to
return piston 58 to a vertically extreme upwards position when
pressurized air is not furnished to piston-cylinder combination
34.
[0025] A first solenoid designated generally 40 actuates a first
air valve designated generally 46 to supply compressed air via a
line 61 to first piston-cylinder combination 34, thereby to push
piston 58 downwardly. Fixed to piston 58 is a connecting rod 62 to
which first pusher 28 is affixed, at the end of connecting rod 62
remote from piston 58. First, second and third piston-cylinder
combinations 34, 36, 38 rest on plate 66 and are retained in
position thereon by suitable nut and bushing combinations, one of
which is designated 64 in FIG. 1. Connecting rod 62 passes slidably
within nut-bushing combination 64 as connecting rod 62 reciprocates
responsively to downward force resulting when air is applied to the
upper side of piston 58 and, once that air pressure is relaxed,
when return spring 60 urges piston 58 upwardly into the position in
the position illustrated in FIG. 1.
[0026] In comparing FIG. 1 with FIG. 2 it is evident that liquid
color supply line 22 may be removed from housing 68 in which pump
16 is enclosed. Such positioning of liquid color supply line 22
outside of housing 68 is illustrated in FIG. 2.
[0027] A controller, not illustrated, connects to solenoids 40 via
lines 54 and is programmable so as to permit any desired sequence
of operation of piston-cylinder combinations 34, 36, 38 thereby to
permit any desired sequence of squeezing or unsqueezing of liquid
color supply line 22 when positioned within housing 68 in the
general manner illustrated in FIG. 1.
[0028] First and third pushers 28, 32 are configured outer
peripheries that are curved, and would appear as cylinders if
viewed from the side in FIGS. 1 and 2, facing towards liquid color
supply line 22. These curved outer peripheries are designated 70 in
FIGS. 1 and 2. The curved outer peripheries 70 of pushers 28, 32
facilitates pushers 28 and 32 operating as off-on valves as
respecting flow of liquid color through liquid color supply line
22. Specifically, curved peripheries 70 permit pushers 28, 32 to
act as off-on valves defining first and second positions of tube
closure, with a first position of tube closure being directly
beneath pusher 28 and the second position of tube closure being
directly beneath pusher 32. The curvature of surfaces 70 contacting
liquid color supply tube 22 when pushers 28 and 32 are positioned
against tube 22 and have squeezed tube 22 closed means tube 22 is
closed only over a very short length, immediately beneath pushers
28 and 32, when either of those pushers are actuated by their
associated piston-cylinder combination 34 or 38.
[0029] Contrasting, third pusher 30 has a surface 72 facing liquid
color supply tube 22 that is flat. Surface 72, being flat, results
in liquid color within the portion of tube 22 directly beneath
pusher 30 and along the entire length of surface 72 running
parallel to liquid color supply line 22, being pushed out of liquid
color supply line 22 when third pusher 30 is actuated by associated
piston-cylinder combination 36 and pusher 30 squeezes liquid color
supply line 22 completely closed, thereby forcing all liquid color
material within liquid color supply line 22 beneath the projected
area of pusher 30 towards the outlet of liquid color supply line in
the direction indicated by arrow B in FIG. 1.
[0030] Actuation of a given solenoid such as solenoid 40 by the
controller, via a signal sent to solenoid 40 through line 54, opens
valve 46 thereby allowing pressurized air from a remote source, not
illustrated in the drawings, which is furnished to valve 16 via an
air line not shown in the drawings, to be applied to the upper
surface of piston 58 forcing piston 58 downwardly in FIG. 1 and
thereby actuating, for example, pusher 28 and forcing pusher 28
against liquid color supply line 22, thereby to close liquid color
supply line 22 at a position at first tube closure.
[0031] FIGS. 3A through 3F depict one desired and preferred
sequence of operation of pushers 28, 32, 30 to pump liquid color
through liquid color supply line 22.
[0032] In FIG. 3A pushers 28, 30, 32 are all depicted at an initial
position, at which all three pushers 28, 32, 30 are retracted and
are ready to begin one cycle of pusher movement for pumping liquid
color through liquid color supply line 22. Arrow A denotes that
liquid color is entering liquid color supply line 22 and Arrow B
denotes liquid color exiting liquid color supply line 22 after
passing the position of pushers 28, 32, 30.
[0033] Referring to FIG. 3B, first pusher 28 has advanced to
squeeze liquid color supply line 22 closed at a position to first
tube closure while second pusher 32 and third pusher 30 have not
been displaced. Accordingly, liquid color continues to flow into
liquid color supply line 22 from a supply of liquid color as
indicated by Arrow A, but the liquid color cannot flow past the
first position of tube closure defined by the intersection of first
pusher 28 with liquid color supply line 22, since first pusher 28
has squeezed liquid color supply line 22 closed.
[0034] Next, as illustrated in FIG. 3C, second pusher 32 has been
displaced to squeeze liquid color supply line 22 closed thereby to
define a position of second tube closure, and thereby has trapped
liquid color in the segment of liquid color supply line 22 between
the first and second positions of tube closure as defined by first
pusher 28 and second pusher 32 having squeezed liquid color supply
line 22 closed at the positions shown. Such squeezing and resulting
closure of liquid color supply line 22 traps a portion of liquid
color between the two positions of liquid color supply line
closure, as illustrated in FIG. 3C, between pushers 28 and 32.
[0035] Next, first pusher 28 is retracted by release of the air
pressure through deactuation of the associated solenoid 40 and
action of return spring 60 pushing piston 58 in cylinder 56
upwardly, thereby raising first pusher 28 away from and out of
contact with liquid color supply line 22, as illustrated in FIG.
3D. At the same time, third pusher 30 is actuated, begins to travel
downwardly, and encounters liquid color supply line 22 as
illustrated in FIG. 3D. This encounter begins to compress liquid
color supply line 22 as illustrated in FIG. 3D thereby beginning to
push liquid color out of that segment of liquid color supply line
22 in the direction indicated by Arrow B in FIG. 3D. This liquid
color can only move in the direction of Arrow B in FIG. 3D due to
the continued presence of second pusher 32 in the position
illustrated in FIG. 3D whereby second pusher 32 has closed liquid
color supply line 22 at the position of second tube closure.
Therefore, there is only one direction that liquid color can travel
in response to the tube being squeezed by third pusher 30.
[0036] As depicted in FIG. 3E, third pusher 30 continues its
downward travel, continuing to squeeze liquid color supply line 22
more and more closed, thereby continuing to force liquid color that
was within liquid color supply line 22 below the umbrella of third
pusher 30, out of liquid color supply line 22, in the direction
indicated by Arrow B in FIG. 3E. As was the case illustrated in
FIG. 3D, continued presence of second pusher 32 squeezing liquid
color supply line 22 closed as illustrated in FIG. 3E results in
liquid color within liquid color supply line 22 being able to move
only in a single direction, indicated in Arrow B in FIG. 3E.
[0037] Once third pusher 30 has completed squeezing the liquid
color that is within tube 22 below the umbrella of pusher 30, first
pusher 28 is actuated thereby closing liquid color supply tube 22
at a position of first tube closure, where first pusher 28 has
squeezed liquid color supply tube closed, thereby preventing
passage thereby of any liquid color. Second pusher 32 and third
pusher 30 have been retracted by deactuation of their associated
solenoids, which are not numbered in FIG. 1, with the result that
second and third pushers 30, 32 have retracted to a position above
and out of contact with liquid color supply line 22. As a result,
liquid color again fills the portion of liquid color supply line 22
up to the position of first tube closure defined by pusher 28, with
the liquid color coming from the supply in the direction indicated
by Arrow A in FIG. 3F. From this position the pumping cycle may
repeat. Note that the orientation and positions of first, second
and third pushers 28, 32, 30 is identical in FIGS. 3F and 3B.
[0038] The controller preferably adjusts the speed of pump 16 so
that the desired amount of liquid color preferably is always
supplied by pump 16 at the rate needed for a given material recipe.
Hence, pump 16 is preferably controlled to run faster or slower in
order to maintain a desired rate of liquid color use.
* * * * *