U.S. patent number 3,674,205 [Application Number 05/143,309] was granted by the patent office on 1972-07-04 for multiple color paint spray system.
This patent grant is currently assigned to Champion Spark Plug Company. Invention is credited to Erhard Kock.
United States Patent |
3,674,205 |
Kock |
July 4, 1972 |
MULTIPLE COLOR PAINT SPRAY SYSTEM
Abstract
A multiple color paint spray system for sequentially supplying
selected ones of a plurality of colors to a single spray outlet. A
pair of parallel paint manifolds are each connected to the sources
of a plurality of colored paints and a solvent. Both manifolds are
connected to a single spray gun through a two position valve or to
a group of guns each having its two position valve. While paint of
one color is being supplied to the outlet from one manifold, the
other manifold is conditioned by a solvent purge and filled with
the next color to be supplied so that color change to the spray gun
or guns may be rapidly effected by switching the two position valve
or all the valves simultaneously from one manifold to the other. In
a second embodiment, a four-way valve is used to simultaneously
supply paint of one color to the gun from one manifold to carry the
solvent purge from the second manifold to a disposal source.
Inventors: |
Kock; Erhard (Toledo, OH) |
Assignee: |
Champion Spark Plug Company
(Toledo, OH)
|
Family
ID: |
22503490 |
Appl.
No.: |
05/143,309 |
Filed: |
May 14, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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7465 |
Feb 2, 1970 |
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Current U.S.
Class: |
239/1; 239/112;
239/574; 137/240; 239/569 |
Current CPC
Class: |
B05B
12/14 (20130101); Y10T 137/4259 (20150401); B05B
12/149 (20130101) |
Current International
Class: |
B05B
12/00 (20060101); B05B 12/14 (20060101); E01b ();
E05b 015/02 () |
Field of
Search: |
;239/112,569,574,1
;137/240,606 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Grant; Edwin D.
Parent Case Text
CROSS REFERENCE TO A RELATED APPLICATION
This is a continuation-in-part of my co-pending application Ser.
No. 007,465, filed Feb. 2, 1970 now abandoned.
Claims
I CLAIM:
1. A fluid control system for supplying a selected one of a
plurality of fluids to a single outlet with means for rapidly
changing from one selected fluid to another comprising, in
combination, a single fluid outlet, a first fluid manifold having a
manifold outlet and connected to the source of each of said
plurality of fluids, a second manifold having a manifold outlet and
connected to said source of each of said plurality of fluids, a
plurality of inlet valves for individually controlling fluid flow
from each fluid source into each of said manifolds, a manifold
selector valve operably connecting either said first or said second
manifold outlets to said single fluid outlet, a first and a second
dump valve positioned, respectively, in said first and second
manifold outlets upstream of said manifold selector valve whereby,
while one fluid is supplied to said single fluid outlet through
said first manifold, said second manifold can be preconditioned to
supply another fluid by opening said second dump valve and filling
said second manifold and its manifold outlet up to said open dump
valve with said other fluid.
2. The fluid control system of claim 1 which further includes means
for purging said manifolds with air to remove all other fluids
therefrom.
3. The fluid control system of claim 1 which includes means to
close the fluid inlet valve to said first manifold to terminate
flow of one fluid and to open another inlet valve to initiate flow
of another fluid in said first manifold for a predetermined time
prior to shifting said manifold selector valve to initiate fluid
flow from said second manifold to said single fluid outlet.
4. The fluid control system of claim 3 which further includes means
for opening said first dump valve following movement of said
manifold selector valve to initiate fluid flow from said second
manifold.
5. A multiple color spray paint system for supplying to a spray gun
a selected paint color from one of a plurality of color paint
sources and for rapidly changing from one color to another
comprising, in combination, a pair of paint manifolds each having a
manifold outlet and each connected to the source of each of a
plurality of paint colors, a plurality of paint inlet valves for
individually controlling paint flow of each color paint into each
of said pair of paint manifolds, a manifold selector valve operably
connecting one or the other of said manifold outlets to said spray
gun, and a dump valve in each of said manifold outlets upstream of
said manifold selector valve whereby, while a first color paint is
supplied to said spray gun through one manifold, the other of said
manifolds can be preconditioned to supply another color paint by
opening said dump valve in said other manifold outlet and filling
said other manifold and said other manifold outlet up to said open
dump valve with said other color paint.
6. The multiple color spray paint system of claim 5 which further
includes means for purging said manifolds with air to remove all
other fluids therefrom.
7. The multiple color spray paint system of claim 5 which further
includes a source of paint solvent connected to each of said
manifolds through a pair of solvent inlet valves and means to close
the paint inlet valve to said one manifold to terminate flow of
said first color paint and to open the solvent inlet valve to said
one manifold to initiate flow of solvent in said one manifold for a
predetermined time prior to shifting said manifold selector valve
to initiate flow of said other color paint from said other manifold
to said spray gun.
8. The multiple color spray paint system of claim 7 which further
includes means for opening said dump valve of said one manifold
after shifting said manifold selector valve to initiate flow of
said other color paint from said other manifold.
9. A method of supplying a selected one of a plurality of color
paints and for shifting from such selected one paint to another
selected paint and supplying it to a paint spray gun from a pair of
paint manifolds each having a valved connection to each of said
color paint sources and a valved connection to a source of solvent
with said manifolds alternately connected to said gun through a
manifold selector valve and with each manifold having a dump valve
upstream of said manifold selector valve comprising the steps of
sequentially (1) closing the valve supplying said selected one
color to the one manifold connected to said spray gun and opening
the solvent valve to that manifold to initiate flow of solvent
through that manifold toward said spray gun, (2) moving said
manifold selector valve to connect said other manifold to said
spray gun to terminate flow of solvent toward said spray gun, (3)
and opening the dump valve of said one manifold to direct solvent
flow therethrough.
10. The method of claim 9 which further includes the steps of (4)
opening a paint inlet valve to initiate flow of another selected
color paint from its source into said one manifold and (5)
subsequently closing the dump valve of said one manifold after
filling said one manifold with said other selected color paint.
11. A multiple color spray paint system for supplying to a spray
gun a selected paint color from one of a plurality of color paint
sources and for rapidly changing from one color to another
comprising, in combination,
a plurality of pressurized sources of color paint,
a pressurized source of paint solvent,
a pair of paint manifolds each having a common flow passage in
communication with each of said paint sources and said solvent
source,
a plurality of paint inlet valves in each paint manifold for
individually controlling flow of paint from said paint sources to
said common flow passage of said manifold,
a manifold outlet in each manifold at one end of said common flow
passage,
a solvent inlet valve in each paint manifold at the other end of
said common flow passage and upstream of all of said paint inlet
valves,
a manifold selector valve for alternately connecting one or the
other of said manifold outlets to such spray gun and
a dump valve between said manifold selector valve and the manifold
outlet of each paint manifold.
12. The multiple color spray system of claim 11 which further
includes means for automatically purging one of said manifolds with
solvent through its associated dump valve and for filling it with
another selected color paint while said other manifold is supplying
paint of a selected color through said manifold selector valve to
said gun.
13. The multiple color spray system of claim 11 which further
includes means for opening the dump valve and the solvent inlet
valve to the manifold supplying paint to said gun a predetermined
time prior to shifting said manifold selector valve to connect said
other manifold to said gun.
14. A fluid control system for supplying a selected one of a
plurality of fluids to a single outlet with means for rapidly
changing from one selected fluid to another comprising, in
combination, a single fluid outlet, a first fluid manifold having a
manifold outlet and connected to the source of each of said
plurality of fluids, a second manifold having a manifold outlet and
connected to said source of each of said plurality of fluids, a
plurality of inlet valves for individually controlling fluid flow
from each fluid source into each of said manifolds, a four-way
selector valve simultaneously operably connecting one of said
manifold outlets to said single fluid outlet and the other of said
manifold outlets to a waste outlet, whereby, while one fluid is
supplied to said single fluid outlet through said first manifold,
said second manifold can be preconditioned to supply another fluid
by filling said second manifold and its manifold outlet up to said
waste outlet with said other fluid.
15. The fluid control system of claim 14 which further includes
means for purging said manifolds with air to remove all other
fluids therefrom.
16. The fluid control system of claim 14 which includes means to
close the fluid inlet valve to said first manifold to terminate
flow of one fluid and to open another inlet valve to initiate flow
of another fluid in said first manifold for a predetermined time
prior to shifting said four-way selector valve to initiate fluid
flow from said second manifold to said single fluid outlet and from
said first manifold to said waste outlet.
17. A multiple color spray paint system for supplying to a spray
gun a selected paint color from one of a plurality of color paint
sources and for rapidly changing from one color to another
comprising, in combination, a pair of paint manifolds each having a
manifold outlet and each connected to the source of each of a
plurality of paint colors, a plurality of paint inlet valves for
individually controlling paint flow of each color paint into each
of said pair of paint manifolds, a four-way selector valve operably
connecting one of said manifold outlets to said spray gun and the
other of said manifold outlets to a waste outlet whereby, while a
first color paint is supplied to said spray gun through one
manifold, the other of said manifolds can be preconditioned to
supply another color paint by filling said other manifold and said
other manifold outlet up to said waste outlet with said other color
paint.
18. The multiple color spray paint system of claim 17 which further
includes means for purging said manifolds with air to remove all
other fluids therefrom.
19. The multiple color spray paint system of claim 17 which further
includes a source of paint solvent connected to each of said
manifolds through a pair of solvent inlet valves and means to close
the paint inlet valve to said one manifold to terminate flow of
said first color paint and to open the solvent inlet valve to said
one manifold to initiate flow of solvent in said one manifold for a
predetermined time prior to shifting said four-way valve to
initiate flow of said other color paint from said other manifold to
said spray gun.
20. A multiple color spray paint system for supplying to a spray
gun a selected paint color from one of a plurality of color paint
sources and for rapidly changing from one color to another
comprising, in combination,
a plurality of pressurized sources of color paint,
a pressurized source of paint solvent,
a pair of paint manifolds each having a common flow passage in
communication with each of said paint sources and said solvent
source,
a plurality of paint inlet valves in each paint manifold for
individually controlling flow of paint from said paint sources to
said common flow passage of said manifold,
a manifold outlet in each manifold at one end of said common flow
passage,
a solvent inlet valve in each paint manifold at the other end of
said common flow passage and upstream of all of said paint inlet
valves,
a four-way manifold selector valve for alternately connecting one
or the other of said manifold outlets to such spray gun and
simultaneously connecting the remaining one of said manifold
outlets to a waste outlet.
21. The multiple color spray system of claim 20 which further
includes means for automatically purging one of said manifolds with
solvent through said four-way selector valve and said waste outlet
and for filling it with another selected color paint while said
other manifold is supplying paint of a selected color through said
four-way manifold selector valve to said gun.
22. A method of supplying a selected one of a plurality of color
paints and for shifting from such selected one paint to another
selected paint and supplying it to a paint spray gun from a pair of
paint manifolds each having a valved connection to each of said
color paint sources and a valved connection to a source of solvent
with said manifolds alternately connected to said gun through a
selector valve comprising the steps of sequentially (1) closing the
valve supplying said selected one color to the one manifold
connected to said spray gun and opening the solvent valve to that
manifold to initiate flow of solvent through that manifold toward
said spray gun, (2) shifting said manifold selector valve to
connect said other manifold to said spray gun and to terminate flow
of solvent toward said spray gun and to connect said one manifold
to said waste outlet to direct solvent flow therethrough.
23. A multiple color paint spraying system comprising, in
combination, a first manifold and a second manifold, a plurality of
fluid inlet conduits in fluid communication with each of said
manifolds, a manifold outlet conduit extending from each of said
manifolds to a common selector valve downstream of said manifolds,
a paint spray outlet and a waste disposal outlet operably connected
to said selector valve, and means for alternately directing the
flow of one fluid from one of said fluid inlet conduits through one
of said manifolds to said paint spray outlet and the flow of a
second fluid from another of said fluid inlet conduits through the
other of said manifolds to said waste disposal outlet.
Description
BACKGROUND OF THE INVENTION
This invention relates to a paint spray system in which a plurality
of paints may be selectively supplied one at a time to a single
spray outlet or to each gun of a multiple gun installation. More
particularly the invention is a spray paint control system for
selectively supplying to the spray outlet one of a number of
colored paints and for rapidly changing from one color to another.
The invention may be used with electrostatic or conventional spray
installations and is particularly useful in high speed finishing
applications in which a series of articles to be sprayed or coated
are sequentially passed through a coating zone. In such systems,
such as in the painting of automotive parts, it is desirable to
finish a number of parts in one color and then to rapidly change to
another color. The rapid change is, of course, important to prevent
the necessity of stopping or slowing the conveyor or leaving a gap
between parts on the conveyor while the change-over is taking
place.
It is also desirable when changing from one color to another to
provide for a means for purging the paint lines leading to the gun
with a solvent to remove any paint residue from the previous color,
prior to initiating spraying the next selected color. Apparatuses
which will feed separate colors to a single spray outlet and which
will also permit the operator to clean the spray gun by passing a
solvent through it as a part of the color change cycle are known
and U.S. Pat. Nos. 3,219,273 and 3,145,930 show devices of this
general class.
One of the undesirable features in multiple color spray gun systems
which include a solvent purge, particularly such as those shown in
U.S. Pat. No. 3,155,539 and in my earlier U.S. pat. No. 3,450,092,
is that, in flowing solvent through the paint lines and gun to
remove the residue of the previous paint, the solvent leaving gun
enters the painting zone or spray booth which increases the fire
hazard due to the volatility of the solvent. This is particularly
true in systems where the solvent purge is conducted at an
increased flow rate which is necessary to reduce the time for color
change in order to keep pace with the movement through the spray
zone of the objects being coated. The increased flow rate, due to
increased supply pressure, will cause an increase in the spray area
of the exiting solvent to further compound the fire hazard.
SUMMARY OF THE INVENTION
This invention provides a control system for a paint spray
apparatus which is capable of rapidly switching from one selected
paint color to another, which includes a means for providing a
solvent purge to remove paint residue from the entire system except
for the relatively short passages within the spray gun itself and
which does not allow any solvent to enter the spray zone. These
objects are accomplished through use of a pair of parallel
connected paint manifolds which are each connected to the sources
of colored paints and solvent and with each manifold connected to
the spray gun or guns through a two position manifold selector
valve. This valve is moved to alternately connect one or the other
manifold to the spray gun. When multiple guns are used in one
installation for spraying the same color, each gun may have its own
manifold selector valve which are switched simultaneously so that
all guns are shifted from one manifold to another.
Positioned adjacent the manifold selector valve and in the line
connecting it to the manifold is a dump valve for each manifold
which, in one position, allows the paint from that manifold to the
manifold selector valve and, in the other position, directs paint
from that manifold to a waste dump, bypassing the manifold selector
valve. In a second embodiment a four-way manifold selector valve is
used to simultaneously supply paint of one color to the gun from
one manifold and direct a solvent purge from the second manifold to
a disposal source. With this system, and suitable valve controls,
one manifold can be purged and filled with the next selected color
paint while the other manifold is still supplying a first selected
color paint to the spray gun. Upon movement of the manifold
selector to connect the other manifold to the gun, only a small
amount of the old paint residue must be forced out through the gun
prior to initiating spraying with the newly selected paint and no
solvent enters the spraying area. The operation and advantages of
this system will be more fully understood from the following
detailed description of a preferred embodiment thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of the dual manifold paint supply
system of this invention, showing paint manifolds I and II each
connected to a pressurized source of air, solvent, and paint colors
A-D. The outlets of the manifolds I and II are shown connected to a
single spray gun through the manifold selector valve.
FIG. 2 is a schematic diagram of a second embodiment of the dual
manifold paint supply system of the invention showing the outlets
of manifolds I and II connected to a four-way manifold selector
valve.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a pair of paint manifolds, designated I and
II, are shown with each having an elongated flow passage 10
extending throughout its length with the lower end of the flow
passage 10 connected to a manifold outlet line 11. As schematically
shown in the drawing, each manifold is formed by a plurality of
valve segments which are secured together in a row to form an
elongated manifold having a common flow passage extending
throughout its length.
As illustrated in the broken away portion of manifold II, a series
of inlet valves, each one contained in a valve segment, is
connected to the flow passage 10 from top to bottom. Each of the
corresponding inlet valves in each of the manifolds is connected
through fluid supply lines 12-17 to a pressurized source of air,
solvent and paint colors A-D. It should be understood that any
number of paint colors can be utilized in this system with larger
manifolds which provide a separate fluid inlet valve for each
individual paint color and that the illustrated system which
includes only air, solvent and four paint colors is not intended to
limit the number of fluids which may be controlled using the
principles of the present system.
Each of the fluid inlet valves is pneumatically controlled by an
air cylinder which, when actuated, moves to the left in the drawing
of manifold II to open the fluid inlet valve for flow from the
fluid supply controlled by that valve to the flow passage 10 within
the manifold. In the drawing, the inlet valves and air cylinder for
manifold I are designated as I-air, I-S (solvent), I-A, etc. while
the inlet valves and air cylinders for manifold II are designated
in a similar manner. Each of the air cylinders controlling the
inlet valves are connected to a source of control air pressure
through air lines 18 and 19 leading from a control air supply to
branched air headers, each of which are connected to the
appropriate air cylinder through electrically controlled air valves
20-31 as indicated. A visual indicator 32 may be connected in each
header line between the air valves 20-31 and the appropriate air
cylinder. The indicators 32, the details of which are not shown,
provide a visual indication of the position, open or closed, of the
appropriate paint inlet valve. It is apparent that the fluid inlet
valves could also be electrically controlled using a solenoid
winding directly acting upon the valves.
The manifold outlet line 11 from each of the manifolds I and II is
connected to a manifold selector valve which is a two position
valve for alternately connecting one or the other of the manifolds
I or II to the spray gun through a spray gun supply line 33. The
position of the manifold selector valve is shown as connecting
manifold II to the gun supply line 33. The manifold selector valve
is pneumatically controlled through air control lines 34 and 35
which are connected to the control air line 18 through a branch
line 36 and an electrically controlled air valve 37. The air valve
37, as shown in its lower position, connects control air pressure
to the line 34 while, in the upper, dotted line position, the
control air is connected to the air control line 35 which will move
the manifold selector valve to its other position to connect paint
manifold I to the gun.
A pair of bypass or dump valves I and II are connected to the
respective manifold outlet lines 11 on either side of the manifold
selector valve as shown. The dump valves I and II are pneumatically
controlled by electrically controlled air valves 38 and 39 and have
an open position, in which the manifold outlets 11 are connected to
a dump line 40 which leads to a waste collector 41. In their closed
position, the dump valves I and II close communication between the
dump line 40 and the manifold outlet lines 11. The position of the
dump valves I and II is shown by indicators 42. The dump valves I
and II and the manifold selector valve could also be controlled
electrically.
The supply of control air to each of the air solvent and paint
inlet valves in both manifolds, the manifold selector valve, and
the two dump valves I and II is electrically controlled so that a
valve control apparatus can be positioned in a control station
remote from the spray booth. The electrical control apparatus can
be a manually operated push button type in which the operator has
an appropriate button for changing the position of each of the
valves so that any desired operating sequence, as will be
subsequently explained, can be manually controlled by the operator
Preferably however, the electrical control for the control air to
the valve includes an automatic or semi-automatic cycling device
which is preprogrammed in accordance with the speed of the conveyor
carrying the articles through the spray booth and desired color
variations for those articles so that semi- or fully automatic
color change can be preprogrammed into the electrical control
apparatus. One such device which has been successfully incorporated
and which is representative of a number of mechanical-electrical
memory devices is generally known as an "Edon Chain" which is
marketed by the Edon Industrial Products Company, 2891 Industrial
Row, Troy, Mich. 48084. This device is a driven endless chain
having a plurality of movable pins which can be placed along the
chain to actuate electrical switches positioned in the path of the
pins to open or close circuitry to control the position of the
fluid valves in the color change system thus described. Other
electro-mechanical memory devices including punch card or tape
controlled computers may be readily adapted to program the desired
sequence of valve operation in the previously described system and
will be apparent to those skilled in the art.
Using the color change apparatus previously described and as shown
in the drawing, the following are two examples of an operating
sequence which may be used to rapidly effect the change from
spraying one color to spraying with another color.
EXAMPLE
Assume that the spray gun is spraying the objects to be coated with
paint color A from manifold II. In this condition, which is that
shown in the drawing, both of the dump valves I and II are closed,
the manifold selector valve is in the position to connect manifold
II with the gun, the paint inlet and its air cylinder II-A are open
while the valves II-air, II-S and the other paint valves in
manifolds II are closed.
Assume that it is desired to spray with paint B for a given time
and to subsequently change again to spray with paint C. Manifold I
will have been previously conditioned, as will be subsequently
described, so that it is filled with paint B in the manifold outlet
line 11 up to manifold selector valve. With the controller
programmed to switch spraying to paint B and then to paint C, the
following valve movement sequence takes place:
1. The manifold selector valve moves to its alternate position to
connect manifold I to the spray gun through line 33. This of course
cuts off manifold II and the gun changes to paint B as soon as the
remaining paint A is pushed out of line 33 through the spray
gun.
2. Dump valve II opens.
3. Inlet valve II-A closes and inlet valve II-S opens so that
solvent purges the common flow passage 10 through manifold II,
pushing paint A out the dump valve II into dump line 40 to the
waste collector 41.
4. Inlet valve II-S closes and inlet valve II-C opens, so that the
new paint color C pushes solvent out through the dump valve II to
fill the lines leading to the manifold selector valve with paint
C.
5. dump valve II closes. In this condition, manifold II is now
preconditioned to be ready to immediately supply paint of color C
to the gun as soon as the manifold selector valve is again moved
and the above sequence is repeated on corresponding valves on the
other manifold.
In the above described sequence of Example I, it should be noted
that solvent never enters the spray booth through the spray gun,
that each manifold is preconditioned to spray another color paint
while the other manifold is supplying paint to the gun so there is
no down time, and that the common flow passage 10 in the manifold
and the lines leading up to the manifold selector valve are purged
with solvent prior to introduction of another color of paint.
EXAMPLE II
Again assume that paint A being supplied to the gun through
manifold II with the manifold selector valve in the position as
shown. Assume that manifold I has been preconditioned and filled
with paint B, as described with reference to Example I. With the
electrical control programmed to switch from paint A to paint B and
later to paint C, the following sequence of valve operation takes
place:
1. Inlet valve II-A closes and valve II-S opens. In this condition,
solvent pushes paint A through the common flow passage 10 of
manifold II towards the manifold selector valve.
2. The manifold selector valve moves to its alternate position to
connect manifold I and paint B to the spray gun. This stops the
flow of solvent through the manifold outlet line 11 until dump
valve II is opened. The time delay between the opening of the
solvent valve II-S and the switching of the manifold selector valve
is such that the solvent which is purging paint A from manifold II
will completely clear manifold II itself but will not reach the
manifold selector valve. This time interval, is of course dependent
upon the length of the manifold outlet 11, and the rate of paint
flow and is easily determined for a given installation. This system
has the advantage in that while paint A in the manifold is being
purged by the solvent, most of the paint A in the system ahead of
the solvent is pushed out to the spray gun, thus reducing the
amount of paint loss in a color changeover.
3. Valve II-S closes and valve II-C opens so that paint C pushes
solvent out of the manifold II and manifold outlet line 11 through
the dump valve II.
4. dump valve II closes so that manifold II is now preconditioned
to immediately supply paint C as soon as the manifold selector
valve is again switched to its position shown in the drawing.
It should be appreciated that in either of the operational
sequences described in Examples I and II above, the dual manifold
system has the advantage of providing almost instantaneous change
from one color to another. Because each of the manifolds is being
purged and conditioned with a subsequent paint while the other
manifold is still supplying a desired paint to the spray gun, the
amount of time for an effective color change is substantially
reduced. For example, using a built up manifold of 45 inches in
length, the volume within the manifold's internal passages is about
70 cc. When changing from one color to another with an intermediate
solvent change, the replaced liquid must be scrubbed in effect by
the subsequent liquid so that several volume changes within the
manifold are necessary. For example, with a solvent flow rate of
600 cc per minute, it would take approximately 40 seconds to purge
that manifold of a previous color with solvent and refill it with a
subsequent color. Using the system of this invention, the complete
color change can be effected in approximately 2-3 seconds,
depending upon the length of the paint supply line 33. It is to be
understood that the only time delay in changing from one paint to
another in the instant system is that required to flow the new
paint through the line 33 to the gun. By positioning the manifold
selector valve as close as is possible to the gun, this time is
reduced to a minimum.
To further accelerate the paint change cycle, the source of solvent
may be under a pressure higher than that of the paint sources so
that supply line 13 and solvent flowing through the manifolds I and
II when the valves I-S or II-S are open is under higher pressure
and thus flows at a higher rate. The higher solvent pressure also
improves the purging action in the interior of the manifolds. Such
increased solvent pressure does not present any undesirable fire
hazards in the present system because no solvent flows through the
gun, as would be the case with prior art color change systems.
An air purge to dry the manifold interior and prevent solvent
dilution may be included in the present system, using a source of
air under pressure connected to the manifold I and II as shown in
the drawing. If an air purge following the solvent purge is
desired, the operating sequence of Examples I and II would include
the step of closing the appropriate solvent inlet valve and opening
the appropriate air inlet valve for a predetermined time to push
out solvent with air. Finally, it should be noted that in each
case, the solvent and air inlet valves are positioned in the
manifold at the end remote from the manifold outlet line 11 so that
solvent and air purges are effective to scrub the entire length of
the common flow channel 10 in the manifolds.
It will be apparent to those skilled in the art that the timing of
valve movements in the sequence described in Examples I and II may
be varied to fit the desired installation to attain the advantages
provided by the dual manifold system of this invention. The timing
and sequence of opening and closing each of the valves is, of
course, dependent upon the frequency with which the articles to be
sprayed are presented in the spray zone and the particular
selection of color sequence is, of course, dependent upon the
desired color output for the articles being coated.
Referring to FIG. 2, a second embodiment substantially similar in
function and structure to the first embodiment described above is
shown. In this embodiment, a four-way manifold selector valve 43 is
positioned between the outlet lines 11 from manifolds I and II. The
four-way manifold selector valve 43 combines the functions of the
manifold selector valve and the dump valves I and II shown in FIG.
1.
The four-way valve 43 comprises a body 44 having a valve inlet 45
connected to the manifold outlet 11 from manifold I and a valve
inlet 46 connected to the manifold outlet 11 from manifold II; a
spray gun supply outlet 47 and a waste disposal outlet 48. A
rotatable cylindrical valve member 49 is located within a
complementary bore 50 in the body 44. Two curved passageways 51
within the cylindrical valve member 49 provide fluid communication
simultaneously from one of the valve inlets 45 or 46 to the gun
supply outlet 47 and from the other of the inlets 45 or 46 to the
waste disposal outlet 48.
The valve member 49 may be rotated by air actuated means to
alternatively direct fluid selected from a color source in one of
the manifolds, as described above, to the gun supply outlet 47 and
purging fluid from the second manifold to the waste disposal outlet
48. A single dump valve 52 downstream of the waste disposal outlet
47 provides a means for controlling fluid flow from the purging
manifold to the waste collector 41.
Thus, for example, when the four-way selector valve 43 is
positioned as shown in FIG. 2, a selected color from manifold II is
supplied to the spray gun and the solvent and air purge being
cycled through manifold I is sent through the waste disposal outlet
48 to the waste collector 41. Prior to effecting a color change,
solvent flow in manifold I from the solvent supply line is
terminated and flow from a selected color supply line to purged
manifold I is initiated, pushing the remaining solvent through the
waste disposal outlet 48 and the single open dump valve 52 to the
waste collector 41. The color flow through manifold I toward the
waste collector is terminated by closing the single dump valve 52.
Thus a selected color under pressure is now in manifold I and the
manifold outlet line 11 up to the four-way selector valve 43.
To effect color change, the cylindrical valve member 49 is rotated
90.degree. to place the manifold outlet 11 from manifold I in fluid
communication with the spray gun supply outlet 47. Since the
selected color from manifold I is already in the manifold outlet
line 11 prior to shifting the four-way valve 43, the new color will
rapidly enter the gun supply line 33 and the gun when the valve 43
is shifted. Shifting of the four-way valve 43 will also place
manifold II in fluid communication with the waste disposal outlet
48 as described. The purging cycle is now initiated in manifold II.
Thus the four-way valve 43 provides means for simultaneously
directing a selected color to the spray gun from one manifold and
purging fluid to the waste collector 41 from the second manifold
and means for realigning the manifold outlets 11 to exchange color
supply and purging cycles from one manifold to the other. Other
advantages of the present system in various modifications thereto
will be apparent to those skilled in the art and may be made
without departing from the spirit and scope of the following
claims.
* * * * *