Note: Descriptions are shown in the official language in which they were submitted.
~s~
COLOR CHANGER
This invention relates to color changers and
more particularly to apparatus for selectively provid-
ing paint of various colors to paint appllcator
apearatus .
Attention is directed to applicants` related
co-pending patent application, Serial No. 4
entitled "Circulating Color Changer with Improved
Valve and Manifold," filed on even date herewith,
James ~olibas, inventor.
There have been numerous color changer
devices for controlling the alternative delivery of
paint of selected colors to spraying apparatus,
stopping of non~selected colors, and cleaning of the
system between color selection operation. Various
kinds of color changers today in use, however, have
certain inherent disadvantages.
Such disadvantages are frequently the result
of specific parameters or characteristics of the
particular paint to be used, such as the paint's
viscosity or its solids content. For example, in many
painting systems, heat is required to reduce the
viscosity of otherwise heavy or thick paint to a point
where it can be more easily sprayed~
Where heat is utilized, it is known to apply
heat to the paint at specific locations in the system.
If paint flow is stopped for any significant time,
paint at the heat location may be overheated, and
charred, or otherwise damaged. Likewise, paint remote
from -the heaters cools. This affects the paint's
viscosity and thereby causes variations in paint
atomization and finish.
Some paints, such as the metallics ! for
example, may include solids which should be maintained
in uniform suspension throughout the supply and piping
system during any application operation.
The same stoppage of paint flow for any
significant time may let solids within the paint
settle out of the desired suspension, producing a
non-uniform coating in sprayed paint and electrostatic
grounding problems.
~0 ~nown color changers for high pressure
svstems operating at ranges exceeding 1000 psi, for
example, are generally referred to as dead-end, or
non-circulating to gun, changers. Paint is generally
conveyed to the applicator gun, moving through a
system including a color changer manifold. ~owever,
when the gun or applicator is shut down, or the
particular paint color is not being selected, paint
flow is stopped between the changer manifold and the
.' ~: . ' : ` '
8'~
--3--
gun with paint circulating between the paint supply and
manifold only. The paint which is dead ended between the
manifold and gun can cool. Even where there are no
temperature gradients, for example, solids can settle out of
suspension. Thus, in a heavy or viscous metallic paint, ~or
e~ample, paint in such known systems may be subjected to both
un~esirable cooling and set~ling. Prior recirculating
changers for low pressure systems operating in the range of 80
to 200 psi, for example, utilized bellows devices for
1~ separating and sealing paint from elements of the paint valve
actuators. Such bellows rupture and break, however, if usecl
in a high pressure system at 1000 psi and above, for example.
Accordingly, it has been one objective of the
inven~ion to provide an improved color changer.
A further objective of the invention has been to
provide an improved color changer which prevents paint
overhPating, temperature gradients, or solids Erom settling
ou~ of suspension for both the paint selected and the paint of
non-selected colors.
~a Anothex objective of the invention has been to
provide an improved color changer having apparatus
facilitating the addition or removal of any number of speciEic
colors ~o be changed.
A further objective of the invention has been to
provide a fully recirculating color changer for a high
pressure paint applying system.
~n/rm
--4--
To these ends, an improved color changer
according to a preferred embodiment of the invention
preferably includes a plurality of identical changer
modules, one module for each color of paint to be
selected, and providing for full recirculation of
paint of all non-selected colors, and a continuous
recirculation return to supply of excess paint of a
selected color during a spraying operation in a high
pressure painting system.
The changer includes a universal applicator
supply manifold and a universal applicator return
manifold, defined respectively by interconnected bores
in a plurality of module supply and return blocks.
Each module also includes a recirculation block
defining a recirculation passageway.
~ A normally closed supply valve, in each
module, passes paint of a non-selected color to a
normally closed, but pneumatically opened recircu-
lation valve on the recirculation block. Paint is
thus passed back to its supply through the recircula-
tion passage. ~hen paint of this color is selected,
the supply valve is pneumatically opened, the recircu-
lation valve closed, and paint is conveyed to the
supply manifold block of that module, and thus to the
universal supply manifold, the spray guns, and the
universal return manifold. From the return manifold,
the paint flows to the return manifold block of the
module and to a normally closed, but now ~opened,
,
~, .
return valve. The return valve iq mount~d t~ th~
recirculation block and passes paint to the common
recirculation passage and back to the supply.
Each module thus preferably includes a
supply manifold block, a return manifold block, a
recirculation block and pneumatic piston controlled
supply, recirculation and return valves connec~ed
respectively thereto, as noted, for supplyin~ and
receiving a selected paint of one color to and from
universal manifolds and the supply, for recirculating
paint o the one color to the supply when that color
paint is not selected, and for recirculating unused
paint of the one color when the one color is selected.
No bellows are used in the respective
valves, and thus the changer is particularly useful
for high pressure airless spraying.
One module is provided for each paint color,
and each module is provided with bores and sealable
porting so it can be easily stacked and secured by
screws to an adjacent module. In order to increase
the number of colors a basic color changer according
to the invention can handle, it is only necessary to
add modules to the basic changer. For example, it is
easy to increase the number of colors a basic two-
color changer can handle merely by stacking the samenumber of add-on modules required for the number of
colors to be added.
'
J~
--6--
The assembly of modules is easily accom-
plished, with each module including and defining its
own portion of the universal supply and return mani-
folds. No additional piping or connections, except
- 5 lines to and from the additional color supply, and to
and from the valve control solenoid, are required.
Moreover, the full recirculating capabil-
ities noted above are retained wi~hout long or signif-
icant stagnant areas for any paint during a painting
operation. Also, areas of non-flow, such as between
the supply and recirculation valves of a selected
module when the paint of that module is being sprayed,
are eventually recirculated through the supply and
system before further application where it is homogen-
ized as to heat and mixture.
DuJe to the interconnection of the manifoldblocks, pressure drop through the system is not
significantly increased as it might be if each addi-
tional color required further piping between the
manifold portions of each module or paint valve ports.
In addition, and according to the invention,
separate solvent and air modules are provided for
cleaning the color changer between color changes. The
solvent and air modules are disposed upstream in the
universal supply manifold. The dump valve is disposed
downstream in the universal return manifold, to
provide for entire system cleaning between color
changes. These modules do not require recirculation
:
. . . I .
,
~5 !3 ~ '
valves or recirculation blocks as the used solvent is
simply piped to the dump valve, and the air is also
vented or piped to the dump valve.
Accordingly, the color changer of the
invention can be particularly effective with high
pressure airless systems. Where the changer is used
in high pressure systems, the valves may be provided
with additional springing to help the valve close when
high pressure flow may otherwise tend to keep it open.
The invention thus provides a recirculating
color changer wherein paint o~ all non-selected colors
is continually recirculated, and excess paint of a
selected color is also returned to supply.
Add-on modules define their own portions of
universal supply and return manifolds, and can easily
be added to a basic changer to handle additional
colors, while retaining the full recirculation advan-
tages described above in a high pressure spraying
system.
These and other objectives and advantages
will become readly apparent from the following de-
tailed description of a preferred embodiment of the
invention and from the drawings in which:
Fig. 1 is a diagrammatic, exploded, perspec-
tive view showing a three~color color changer accord-
ing to the invention;
Fig. 2 is a cross-sectional view of a single
color module taken along lines 2-2 of Fig. 1, and
showing a paint flow path for a selected color, the
dots or stippling indicating paint flow;
Fig. 3 is a diagrammatic cross-sectional
view similar to Fig. 2, but showing a paint flow path
when the paint color of the module is not selected,
the dots or stippling indicating paint flow;
Fig. 4 is a diagrammatic cross-sectional
view of a valve actuator of a valve of Fig. 2 showing
a helper spring used for high pressure systems; and
Fig. 5 is a diagrammatic view taken on lines
5-5 of Fig. 1 and similar to Fig. 2, but showing
solvent cleaning appàratus.
Turning now to the drawings, there is shown
in Fig. 1 thereof a color changer 10 according to a
preferred embodiment of the invention. It will be
appreciated that color changer 10 is particularly
adapted for utilization in painting systems which are
utilized to apply more than one particular color to an
object. Multiple-color painting systems are utilized
in many varied applications.
It is frequently desirable to apply paint of
different types within an application system, such as
normal paint of one or more given colors and other
paints having solids therein, such as metallic paints,
for example.
It will be appreciated that the color
changer 10, as described herein, is useful in a
variety of varying types of painting systems where it
~'
:
~2'~5~ t
_9_
is desired to utilize more than one color or type of
paint for application by a particular applying appara-
tus, such as an electrostatic paint spraying gun or
other form of applicator.
- S It will also be appreciated that color
changers are utilized in high pressure systems, that
is, on the order of about 1000 psi and above, such as
2000 to 3000 psi.
As shown in the drawings, color changer 10
includes what will be referred to as a basic two-color
color changer 11 and an additional color module means
12 added to the basic two-color changer 11, so as to
form a three-color colox changer 10 as shown in Fig.
1. The color module 12 is shown in exploded form from
the basic color changer 11 for illustrative purposes
only and it will be appreciated that in use; the color
'` module 12 is connected to and operatively associated
with the basic color changer 11 to form the integral
color changer 10.
Also it will be appreciated that normally
color changers are utilized where two or more difer-
ent colors or different types of paints or fluids are
to be utili2ed within the system. Accordingly, the
basic color changer 11 is provided with means for
selecting between two different colors or types of
paints and it will be appreciated that additional
color modules, such as the module 12, can be added to
make a multiple-color color changer to provide a color
.~
`
--10--
changer having ~he capacity fo~ selecting between three or
more different colors or types of paints or fluids to be
handled by the system. Basic color changer 11 can thus be
made-in a unitary construction, or can be assembled from
modules such as module 12, and appropriate solvent and air
pur~e and dump valve components.
~ eferriny now to more of the details of the color
chan~3er as shown in Fig. 1, it will be appreciated that the
color changer 10 includes a universal paint supply maniEold 13
and a universal paint return manifold 14. As shown in Fig. 1,
the manifolds 13 and 14 are deEined by machined aluminum
blocks, such as at 15 and 16. As shown in Fig. 1, the blocks
15 and 16 are integral and extend throughout the basic two-
~olor color changer 11. It will be appreciated that the
blocks 15 and 16 could be manufactured in separate assemblies,
on~ block or each color, as will be described with respect to
tl~e color module 12.
It will be further appreciated that the manifolds 13
and 1~, respectively, eventually terminate at ports 17 and 18,
located in terminal blocks 19 and 20, respectively, for
conneotion to appropriate conduits leading to and from
appropriate paint spraying guns, for example. Terminal blocks
19 and 20 are used at the end of changer 10 for this purpose
regardless of the number of modules used in the changer.
rn/rm
,
~5~
Considering the color module 12, it will he
appreciated that this module includes a paint supply
valve 25, a recirculation valve 26 and a paint return
valve 27, not particularly shown in Fig. 1 but more
readily seen in FigsO 2 and 3. The module 12 also
includes a supply manifold block 28, a return manifold
block 29 and a recirculation block 30. Supply valve
25 and recirculation valve 26 are connected together
by means of a connecting block 31 disposed there-
between and containing a bore 32 therethrough, opera-
tively connecting a constantly open output port 33 in
valve 25 to a constantly open input port 34 in the
valve 26. In similar fashion, a connecting block 36
is mounted and extends between the return manifold
block 29 and the return valve 27. Block 36 includes a
bore 37 therethrough, interconnecting an output port
38 of the manifold block 29 with an input port 39 of
the return valve 27.
It will also be appreciated that the respac-
~0 tive recirculation valve 26 and return valve 27 areboth operatively mounted on the recirculation block 30
which defines a common recirculation passageway 41
therein.
It will also be appreciated, particularly
from viewing Figs. 1 and 2, that the supply manifold
block 28 contains and defines a portion 13a of the
universal supply manifold 13. Likewise, the return
manifold block 29 defines a portion 14a of the
universal return manifold 14. The supply manifold
portion 13a and the return manifold portion 14a are
situated as shown in Fig. 1 to eventually be connected
to the specific supply and return ports 17 and 18 of
5 the terminal blocks 19 and 20. of course, where other
modules are utilized, each of the modules includes 'à
supply manifold block 28 and a return manifold block
29, each of which defines a respective portion of the
supply and return manifolds 13 and 14 in a similar
fashion, as does the module 12. ~ealing means, such
as grooves and O-rings, may be provided on abutting
faces of the manifold blocks to prevent leakage along
manifolds 13, 14.
Referring again to Fig. 1, it will be
appreciated that the basic two-color color changer 11
also includes equivalent structure to the module 12
for each specific color to be applied. That is, for
example, the apparatus for selecting color number 1
includes a supply valve 25a, a recirculation valve
26a, and a return valve 27a lnot shown), all of which
correspond ~o the supply recirculation and return
valves 25-27, respectively, of the module 12. Like-
wise, the apparatus for selecting paint color number 2
includes a supply valve 25b, a recirculation valve 26b
and a return valve 27b, all of which also correspond
for example to the supply recirculation and return
valves 25-27 of the module 12. Of course' and as
noted above, it would be possible to provide each of
.~
.,
-13-
the cspparatus for color number 1 and color number 2 in
separate modular form, identical to that of module 12.
Nevertheless, it may be more economically advanta~eous to
provide the basic two-color color cllanger 11 in the form as
shown in Fig. 1 as an integral unit, since the basic color
cllallger will be utilized for operations requiring only two
colors and one or more identical modules 12 added thereto wlle
~daiciollal colors or types of paints are to be utili~ed in the
system.
It will also be appreciated that the basic two-
eolor changer 11 also includes means for cleaning the entire
system between changes of color or types of paint. In this
regard, a solvent supply valve 45 (Figs. 1 and 5) is connected
co ~he block 15 and is operatively interconnected with the
- slniversal supply manifold 13 upstream of the apparatus for
applyillg colors numbers 1 and 2. Solvent can be supplied tO
tlle inlet conduit 46 and, when the solvent valve ~5 is opelled,
s~lvent is introduced into the universal supply manifold 13
s~here it can flow out to the guns, back throu~h the return
manifold 14 and then can be conveyed to a dump valve (Fig.
5~. In tllis regard, it will be appreciated that the apparatus
~or introducing solvent for clean~ng purposes into the system
is somewhat similar to the module 12 with the ex~eption of the
lack of any type of recirculation valve, such as the
recirculation valve 26 as shown in Fig. 2. Since it is not
believed necessary to recirculate solvent when solvent is not
~eing utilized in the system, the solvent valve 45 does not
~n/rm
-14-
include an outlet port 33, which port is simply closed up, for
e~ample, wllere a similar type of valve is utilized. Also, it
will be appreciated that any outlet port from any
recirculation block, such as circulation block 30, which might
be utilized with the solvent apparatus, is also closed up,
e~cept as such port leads to a solvent and waste paint dump.
~ ccordingly, the solvent supply valve ~5 can be
opened to admit solvent to the universal supply ~anifold 13.
From there, solvent runs through the conduit to the spraying
1~ apparatus, back to the universal return manifold 14 an~
through a dump valve 453, which is a valve similar to the valve
27 shown in Fig. 2. A diagrammatic illustration of the
solvent apparatus is shown in Fig. 5, wherein the dump valve
4~ can be opened to pass solvent and waste paint to a waste
t~nk (not shown).
It will be appreciated that the solvent can thus be
run tllrough the system from upstream of all colors at an
upstream portion of maniold 13, throughout the system to a
dump downstream of all return manifolds 14 and return valves
2~ ~G ~or thorough cleaning.
After a solvent application through the respective
mani~olds 13, 14 and the remainder of the system, it may be
advantageous to purge any remaining solvent in the system by
blowing pressurized air through the manifolds and other
conduits, paint applying apparatus and the like. In this
regard, an air supply valve is connected to a source of
pressurized air pressure and is mounted on the block 15, being
rn/rm
-15-
operatively conr.ected also to the universal supply maniEold 13
upstream of the solvent supply valve 45. When air supply
valve 50 is open, it serves to pass pressurized air through
the universal manifolds 13, any intervening conduits, the
application apparatus, the return manifolds 14, and through
the dump valve or return valve 48 to the dump, thereby purgin~
solvent fxom the system. Thus, dump valve 4~ is also opened
during the air purge.
Turning now to the details of the particular color
module 12, which are similar to those details for each of ~he
modules or apparatus for applying each of the separate colors
or types of paint including that particular apparatus in the
two-color changer ll, it will be appreciated that each module
or color applying apparatus can be operated independently.
The valves are preferably controlled by pneumatically operated
piStOllS which control the various valves 25-27 in each module
or changer apparatus in a predetermined manner. Each module
is selectively operated in order to select a particular color
for application by a paint applying apparatus and at the same
xn/xm
, ~. ,,
. - . ,
-16-
time provide recircula~ion for paint of that color
when such paint is not being selected.
Turning now to the details of Figs. 2-5, it
will be appreciated that the particular valves which
are utilized in the color changer 10 each constitute a
valve of the type referred to by applicant as an A7A
valve, which applicant has used in non-circulating
dead end color changers.
Each of the valves 25, 26 and 27 are simi-
lar. Beginning with supply valve 25, that valve 25 isconnected to a paint supply conduit 55, connecting a
supply of paint to valve port 56. The supply valve
itself includes a valve seat 57 and a reciprocating
valve member 58, preferably comprising a ball-like
member 58 as shown. Valve member 58 is mounted on a
reciprocal stem 59 connected at its upper end to a
pneumatically operated piston 60. Stem 59 is provided
above the paint inlet chamber 61 with any necessary
sealing in order to maintain the paint within the
valve body and to prevent it from leaking upwardly.
W~ep holes 64 prevent any paint which does leak
upwardly from entering the air system for the pneumat-
ically operated piston 60; Each of the modules may
include air inlet ports, such as ports 62 (see Fig.
1), for supplying pressurized air to expansible
chambers 63. It will be appreciated that the respec-
tive air inlet ports 62 may be provided with appropri-
ate air fittings for selective connection to a source
.
-17-
of selectively controlled pressurized air, or to an
exhaust. When it is desired to close the valve 25,
air pressure in chamber 63 is exhausted back through
inlet port 62 and the valve spring 65 operates to urge
the stem 59 and the ball member 58 against the seat 57
to close off the passageway through the seat. It will
also be appreciated that supply valve 25 is controlled
so as to be a normally closed valve, wherein the valve
is normally positioned such as shown in Fig. 3.
~n the condition as shown in Fig. 3, any
paint admitted through the Gonduit 55 into chamber 61
is ducted through the bore 32 to the inlet port 34 of
the recirculation valve 26, which is a normally closed
valve similar to valve 25. Since valve 26 is normally
closed, paint moves through that valve 26 into the
recirculation block 30, only when the valve 26 is
pneumatically opened. When the valve is pneumatically
opened, such as when paint of the color associated
with this module is not selected, paint moves throu~h
the common recirculation chamber 41 and to the paint
return through a suitable conduit, such as paint
return conduit 67, to the supply of paint of the
particular color with which the module is associated.
t will also be appreciated that the return
valve 27, as shown in Fig. 3, is also in its normally
closed position at this time. This prevents any
selected paint of another color, returning in univer-
sal conduit 14, from entering the return to the
.
.
: ` .
5~
-18-
particular non-selected paint color or type controlled
by the module of Fig. 3, as will be described. In
this regard, it will be appreciated that each of the
return manifold blocks 29 also includes a check valve
70, diagrammatically shown in Fig. 2 and 3, for
preventing any portion of the paint between the
manifold block 29 and the return valve 27 from return-
ing into the conduit 14. As will be later described,
when valve 27 is closed, it traps paint between the
seat of valve 27 and the check valve 70. ~his paint,
being non-compressible, serves to hold check valve 70
closed, and thus prevents paint of ano~her color from
passing check valve 70 toward valve 27 and paint
behind check valve 70 from passing forwardly into
manifold 14.
Returning to Fig. 2, it will be appreciated
that the supply valve 25 and the return valve 27 are
normally closed. When a paint color or type associ-
ated with the module of Fig. 2 is selected, these two
valves 25, 27 can be opened by the application of
pressurized air to the expansible chambers beneath the
operative pistons. At the same time, return valve 26
in that module is exhausted through the air inlet 66,
thereby permitting the return spring 73 of the valve
26 to close the ball member 74 of valve 26 against its
seat 75, preventing any paint in the chamber 76 o the
recirculation valve 26 from returning to the common
recirculation passageway 41.
--19--
In this operation, where paint of the
particular module is to be utilized in a paint appli-
cation procedure, the paint is admitted through the
supply valve 25 into the chamber 61 and through the
seat 57 to the universal manifold 13, and particularly
into the portion 13a of the common maniEold in the
manifold block 28. From there, the paint runs down to
or through the manifold 13 where it exits at the
terminal block 19 through port 17 and goes to the guns
or paint applying apparatus, as indicated in Fig. 2.
Of course, it will be appreciated that the
outlets and inlets to and from the paint applying
apparatus as shown in Figs. 2 and 3 are diagrammatic
only and are shown at a 90 angle with respect to
their disposition in Fig. 1 for the purposes of
clarity and to illustrate the flow of paint through
the module when paint of the color which the module
controls is utilized. ,~
From the manifold 13, the paint is circu-
lated to the applicators. Any paint not appliedreturns through the port 18 to the universal paint
return manifold 14. Paint moves along the universal
manifold 14 fills up such manifold 14, and opens the
check valve 70 in the manifold block 29 of the module
which is controlling the paint being used. Paint
flows through the check valve 70, tbrough the now
opened return valve 27 and past check valve 82 into
'.'.'.-'';1` ' ~ ,
,
-20-
the recirculation chamber 41 and Erom there back to the supply
of pain~ for the color being utilized.
It will be appreciated that the flow of paint
through return valve 27, as shown in Fig. 2, is a flow of
excess paint t~hich is not applied by the applicator. In
particular, it will be appreciated that while the applicator
is functioning, a certain amount of the paint admitted to the
sys~em through the supply valve 25 will actually be applied
and will not be returned to the universal return maniEold l~.
EIowever, some of the paint will be recirculated, in the manner
as shown in connection with the description of Fig. 2, back to
the paint supply so that paint is not burnt within the system
an~ so that any solids in the paint do not settle out, but
remain in suspension. Should the applicators be closed off,
for example, then the flow of paint through the module as
shown in Fig. 2 becomes somewhat greater, and s~ill
constitutes a recirculation of paint throughout the system.
It will be appreciated that during this time, all of the other
modules are closed by virtue of the normally closed valves 25
and 27 and the paint color being used merely fills up t~le
maniEolds 13 and 14, exiting only through the module for the
color which has been selected.
It should also be appreciated that while paint
pressurizes the check valves 70 in all return manifolds 14,
only check valve 70 of the module for the selected paint will
open. The other check valves remain closed by the back
pressure of their color paint between the check valve and its
rn/rm
.
.
:~ :
~. ..
~,
-21-
associated, now-closed, return valve 27.
When it is desired to change to another color or
type of paint, the valve 25 and the valve ~7 are released and
closed, while at the same the recirculation valve 26 is
opened, letting the previous color of paint recirculate now
only througll its module. Thereafter, the solvent supply valve
~5 is opened and solvent runs through the supply manifold 13
from upstream o all color modules or apparatus for selecting
a color, thereby cleaning out the universal manifold 13 alld
all downstream conduits and applicators. The solvent is the
returned to the return manifold 14 through the port 18 and
terminal block 20, ana runs through the return manifold 14 ~o
a point downstream of all of the modules or color selecting
ap~ar~tus to the opened dump valve 48, where the solvent is
~etllrned to a waste tank tnot shown). Thus, the entire system
is cleaned by solvent, with paint of the various colors
recirculating through each module and through the valves 2S
~nd ~ thereof. Thereafter, the solvent supply valve is
~losed and, if desired, the air valve 50 may be opened tO dry
~he entire system by directing air through the entire common
supply manifold 13 to the applicator guns and through the
~eturn manifold 14 to the dump valve. In this regard, the
dump valve 48 is retained open while the air is blown there-
through so that air is exhausted through the dump or waste
valve. More typically, the newly selected color would be
introduced directly after the solvent flush to push solvent
remaining in the system out of the dump valve 48.
rn/~)
. .
,.
-22-
It will also be appreciated that each oE the valves
25, 26 and 27 in each of the modules contains a check valve,
such as the check valve 80, 81 and 82, as shown respectively
in valves 25, 26 and 27. These valves prevent any backflow o~
paint, solvent or the like through the respective valves and
yet are easily opened when the valves are opened in order to
pern~it the proper flow of paint therethrough.
It will also be appreciated that each of the valves
is constructed and oriented such that the operative flow of
paint therethrough is in the same direction as the closing
motion o the ball member 58. For exa~ple, the operative flow
of paint through the seat 57 is in a downward direction, which
is the same direction as the ball member 58 would be used to
close that valve. The specific check valves 80, 81 and 82 are
thus utilized to prevent any back pressure which may occur in
the valves from tending to open the main ball members of the
valves and thereby prevent any unintentional opening or
leaka~e o~ paint beyond the valves in an opposite direction o-f
what is intended.
~0 In this regard, it will be noted that check valves
70 and 80 are extremely important to insuring
~n~x~
'
-23-
total integrity of the respective paint colors. ~or
example, in a module whose color is not being selec-
ted, check valve 80 keeps paint of another color in
manifold 13 from openlng valve 25 in the non-selected
module, and contaminating paint therein. Also, the
closing of return valve 27 in a non-selected module
traps paint of that module's color between the seat of
valve 27 and check valve 70. Since this paint is
non-compressible, the trapped paint is useful to hold
check valve 70 closed against passage therethrough of
any paint of another color, or solvent, from return
manifold 14. This contamination of the paint of the
non-selected modules is effectively prevented by the
respective check valves 70 and 80.
Moreover, it will also be noted that as to
paint trapped in the modules between a check valve 70
and return 27, that paint, upon later selection of
that module, is first recirculated through valve ~7
back to the paint supply and then through the system
to the applicators. This insures proper heating of
that paint component, and mixing of any solids therein
prior to application.
It will also be appreciated that each of the
modules is easily stackable or mountable against one
another to define, in part, the respective universal
supply and return manifolds. This is accomplished by
means of appropriate grooves and O-rings in the ports
at the edge of the supply and return manifold blocks
.~
, ;.:~ `~ ' :
' `'' ::: :
,: ~ `
-24-
of the respective modules. It will also be appreci-
atea that the entire changer can be mounted on a
bracket, such as bracket s as shown in Figs. 2 and 5,
for mounting on a framework or any appropriate sup-
porting structure.
It will also be appreciated that the respec-
tive valves, such as valves 25, 26 and 27, for exam-
ple, are connected together through appropxiate
stacking means such as stack screws S in manifold
blocks 28 and 29. For example, valves 25 and 26 could
be connected together via block 31 and appropriate
screws ~not shown~ extending therethrough. Similarly,
the return manifold block 29 is connected to the
return valve 27 by the block 36 and by screws (not
shown). It will also be appreciated that the respec-
tive modules 12 can be connected to the changer 11 and
to additional modules by means of stacking screws r
such as the screws S as shown in Fig. 1.
Turning momentarily now to Fig. 4, there is
shown diagrammatically the top area of a valve, such
as valve 84, which is similar to the valves 25, 26 and
27. Valve 84 is particularly adapted for utilization
in a high pressure, airless paint spraying system, for
~, example. This valve 84 is identical to the valves 25
26 and 27 and a valve 84 is substituted for each of
these in each color module for higher pressure appli-
cation operations. The valve 84 differs only in the
addition of the helper spring 85, which is disposed
~5~
above the piston 86 for supplementing the normal
- spring (such as spriny 65 in Fig. 2) to close the
valve. In this regard, it will be appreciated that
the high pressure flow of paint through such a valve
may, simply by its high pressure, tend to maintain the
ball member off the valve seat, even though air
pressure is removed from beneath the piston 86. In
this regard, the spring 85 may be provided in color
changers which are to be utilized with high pressure
spraying systems in order to insure that the valves
will close when the control air is removed thererom.
While not heretofore msntioned r it will also
be appreciated that each of the valves 25, 26 and 27
includes its own control air inlet port r such as port
62 ~Yhich was described with respect to the paint
supply valve. Such inlet ports, for example, may
comprise the inlet port 66 in the paint recircul&tion
valve 26 as shown in Fig. 1, but not shown in Figs. 2
and 3 for reasons of clarity. Similarly, all of the
return valves, such as valve 27, include air inlet
ports, such as air inlet ports 68b as shown in Fig. 1,
~ith respect to the color changer apparatus for color
number 2.
Accordingly, it will be appreciated that the
color changer according to the invention is capable of
handling numerous different colors which can be
selected by the appropriate application of control
means to the respective valves of the various color
I, i ~
~58~
-26-
modules, or the valves of the basic two-color changer
11, in order to selectively supply paint of a particu-
lar color or type and under high pressures such as
1000 psi or over to an applicator apparatus and
recirculating both non-selected paints, and excess
selected paint to prevent overheating, the settling of
solids, etc.
Accordingly, the invention provides a
modular color changer for selectively supplying paint
to applicators and recirculating unselected paint
constantly to the supply of paints of the non-selected~
colors. It will also be appreciated that the utiliza-
tion of identical color modules and their associated
component portions of the universal supply and return
manifolds makes the addition of numerous colors or
types of paint to a basic color changer an easy task
to accomplish with minimal additional piping and
assembly difficulties while retaining the recircu-
lation capacities for both selected and non-selected
paints. The pressure drop across the additional color
changers is maintained at a very low level due to the
utilization~ of the respective manifold blocks, and
elimination of significant additional piping.
These and other modifications, applications,
and advantages will become readily apparent to those
of ordinary skill in the art, without dieparting rom
the scope of the invention, and applicants intend to
be bound only by the claims appended hereto.
:~2'~
--27--
WE CLAIM:
