Arrangement for cleaning dispense valves

A cleaning nozzle directs a spray of cleaning solution against a dispense valve or other object to be cleaned. The cleaning nozzle is evacuated to draw away cleaning solution, establishing a flow of cleaning solution through the cleaning nozzle. The cleaning nozzle is mounted on an "X-Y table" to follow similarly mounted dispense valves in order to reduce down time for valve cleaning.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to the cleaning of multiple nozzle dispense 
heads, individual dispense valves and other equipment used to dispense a 
flowable medium. 
2. Description of the Related Art 
Dispensing equipment of the type contemplated herein typically includes a 
nozzle or dispense port from which a flowable medium emerges to enter into 
a receptacle. Viscous fluids, for example, tend to accumulate at the 
exterior surface of the nozzle after a dispense operation is completed. It 
may be desirable for reasons of cleanliness, sanitation or metering 
accuracy, to remove such residue, and accordingly several arrangements 
have been proposed to meet this need. For example, commonly owned German 
patent application P 43 31 924.6 proposes a generally cylindrical cleaning 
brush mounted for rotation on a horizontal axis within a vessel of 
cleaning fluid. The vessel is mounted for movement underneath a dispense 
nozzle. The brush is powered so as to rotate, cleaning the dispense nozzle 
by mechanical action of its bristles, and by bringing cleaning fluid to 
the surface of the dispense head as the brush rotates. 
The medium being dispensed may vary widely in its characteristics. For 
example, a medium containing little or no pigment, such as a varnish, may 
be cleaned in a relatively easy manner. However, paints and other coatings 
which are heavily loaded with pigment materials may require considerably 
greater effort and corresponding increased quantities of cleaning fluids 
to successfully complete a cleaning operation. At times, dispense valves 
are employed to meter paint tints which are becoming increasingly 
concentrated over time, to provide a maximum amount of tinting ability in 
a minimum volume of tint material. Accordingly, it can be expected that a 
greater quantity of cleaning material would be required to remove such 
concentrated tinting materials. Perhaps an even greater challenge arises 
when dispense nozzles deliver highly viscous pasty materials in the form 
of offset printing inks. At times, such materials have been known to hang 
in substantial quantities from the underside of a dispense nozzle. The 
difficult flow characteristics of these materials is further aggravated by 
the amount of grit they contain. A brush, or other mechanical cleaning 
media, when brought in contact with such materials, quickly becomes fouled 
and action must be quickly taken to resolve the situation, before the 
materials harden. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved cleaning 
system for dispense nozzles and the like equipment, which deliver flowable 
materials to a receptacle. 
Another object according to principles of the present invention is to 
provide a cleaning system of the above-described type in which contact 
with the residual material is kept to a minimum. 
Another object according to principles of the present invention is to 
provide a cleaning system suitable for use with both static and moving 
dispense nozzles. 
A further object according to principles of the present invention is to 
provide a cleaning system which can employ a number of different cleaning 
solutions in a single cleaning operation. 
These and other objects according to principles of the present invention 
are provided in a cleaning nozzle which comprises: 
a housing having opposed first and second ends, a sidewall extending 
between the first and second ends and an inlet wall at the second end; 
a tapered wall extending from the first end; 
a recess wall joined to the sidewall at a point remote from the first end 
of the housing; 
the recess wall and the sidewall cooperating to form an open ended concave 
recess portion extending into the housing from the first end of the 
housing; 
a standoff wall between the recess wall and the inlet wall, cooperating 
therewith to form an inlet chamber within the housing; 
the tapered wall cooperating with the sidewall to form an outlet chamber; 
the sidewall defining an outlet port communicating with the outlet chamber; 
the inlet wall defining an inlet port communicating with the inlet chamber; 
the recess wall defining a plurality of apertures extending from the inlet 
cavity to the recess portion, so that cleaning media entering the inlet 
chamber has a directed path toward the first end of the housing, whereby 
an external part seated against the housing adjacent its first end will 
lie in the path of travel of the cleaning media; 
the tapered wall defining at least one aperture communicating from the 
recess portion to the outlet chamber so that cleaning media can be 
withdrawn away from the recess portion to the outlet port. 
Further objects according to principles of the present invention which will 
be become apparent from studying the appended description and drawings are 
provided in a cleaning mechanism which includes a cleaning nozzle of the 
above-described type, disposed on a platform which is mounted for movement 
in a plane located adjacent the dispense nozzle. The system comprises 
cleaning apparatus for cleaning a valve, including; 
a nozzle housing having opposed first and second ends, a sidewall extending 
between the first and second ends and an inlet wall at the second end; 
a tapered wall extending from the first end; 
a recess wall joined to the sidewall at a point remote from the first end 
of the housing; 
the recess wall and the sidewall cooperating to form an open ended concave 
recess portion extending into the housing from the first end of the 
housing; 
a standoff wall between the recess wall and the inlet wall, cooperating 
therewith to form an inlet chamber within the housing; 
the tapered wall cooperating with the sidewall to form an outlet chamber; 
the sidewall defining an outlet port communicating with the outlet chamber; 
the inlet wall defining an inlet port communicating with the inlet chamber; 
the recess wall defining a plurality of apertures extending from the inlet 
cavity to the recess portion, so that cleaning media entering the inlet 
chamber has a directed path toward the first end of the housing, whereby 
an external part seated against the housing adjacent its first end will 
lie in the path of travel of the cleaning media; 
the tapered wall defining at least one aperture communicating from the 
recess portion to the outlet chamber so that cleaning media can be 
withdrawn away from the recess portion to the outlet port; 
transport means for transporting the cleaning nozzle about a dispense area, 
comprising: a table supporting the cleaning nozzle, seating means for 
seating the cleaning nozzle against a part to be cleaned by moving the 
cleaning nozzle toward and away from the table, and the transport means 
further comprising x-y indexing means for moving the cleaning nozzle and 
table about a plane.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, and initially to FIGS. 1 and 2, a first 
embodiment of a cleaning nozzle according to principles of the present 
invention, is generally indicated at 10. In the cross-sectional view of 
FIG. 2, only the lower end of a dispense valve 12 is shown. The cleaning 
nozzle 10 includes an outer, generally cylindrical wall 14, which is 
preferably integrally formed with a bottom wall 16 and a mounting flange 
18. A concave recess 20 is formed at the upper end of the dispense nozzle, 
by a generally frustoconical sidewall 22 joined at its lower end to a 
recess wall 24. Members forming recess 20 are spaced above bottom wall 16 
by a generally cylindrical standoff 28, cooperating with the bottom wall 
to form a substantially enclosed entry chamber 30. The bottom wall 16 
defines an opening 34 through which one or more types of cleaning media 
enter chamber 30. 
The standoff 28 and sidewall 22 cooperate with wall 14 and bottom wall 16 
to form a generally annular evacuation chamber 38. An exit aperture 40 is 
formed in wall 14 for communication with a vacuum source, shown 
schematically in FIG. 2 as fan 64. A series of holes 44 are formed in 
recess 24. Cleaning media in chamber 30 passes through holes 44 to recess 
20, exiting through holes 48 formed in sidewall 22, so as to enter 
evacuation chamber 38. 
Cleaning nozzle 10 preferably comprises an elastomeric gasket 50 formed at 
the upper end 52 of sidewall 22, being located adjacent the upper end 54 
of wall 14. As indicated in FIG. 2, the elastomeric gasket 50 is 
dimensioned to sealingly engage nozzle 12, so as to effectively enclose 
recess 20, forming a cleaning chamber therewith. 
In operation, cleaning media enters opening 34 at the bottom of the 
cleaning nozzle, entering chambers 30. The cleaning media then passes 
through holes 44 to enter recess 20. In the preferred embodiment, holes 44 
have a length substantially greater than their cross-sectional size so as 
to collimate or give direction to the cleaning media passing therethrough. 
Cleaning media passing the upper surface of recess wall 24 emerges from 
holes 44, being directed onto the exposed surface 58 of valve 12 with 
sufficient momentum to clean the valve surface. The cleaning media is then 
drawn through holes 48 in wall 22 to enter evacuation chamber 38, being 
drawn out through hole 40 in wall 14. 
In the preferred embodiment, the holes 44, 48 are arranged along two 
concentric circles, and most preferably, are aligned in pairs along radial 
lines. As illustrated in FIGS. 1 and 2, it is generally preferred that the 
holes 44 be located along a circle spaced from the center of the valve 
surface to be cleaned, even though it is important that the center of the 
valve surface be cleaned as effectively as the rest of the surface. 
Further, it is important that the pattern of media flow within recess 20 
does not form pockets of stagnation, with flow streams of media entering 
and exiting the chamber conflicting with one another in a way which 
disturbs a continuous flow through the cleaning nozzle. Accordingly, in 
one of the preferred embodiments illustrated in the figures, it will be 
seen that the sidewall 22 is formed generally at a 45 degree angle and 
that gasket 50 is positioned such that the surface 58 of the cleaning 
nozzle is disposed a distance d from the top surface of recess wall 24. In 
the preferred embodiment, the distance d is generally one-half the radial 
distance r1, a radial distance of holes 44 from the center c of the 
cleaning nozzle, which corresponds to the center of the dispense valve 
being cleaned. Further, the holes 48 are approximately twice as far away 
from center c as are the holes 44, and accordingly r.sub.2 is generally 
twice the distance of r.sub.1. In the most preferred embodiment, the 
distance d is slightly less than one-half the distance r.sub.1 and is 
approximately 45% of the distance of r.sub.1. Further, it will be noted 
from FIG. 1 that the holes 48 are larger in size than the holes 44. It has 
been found that the relative size and location of holes 44, 48 is 
important to ensure a continuous flow of cleaning media through the 
cleaning nozzle 10. With reference to FIG. 2, it will be seen that holes 
48 are spaced above the upper surface of recess wall 24 so as to reduce 
the need for flow exiting holes 44 to reverse in direction, before exiting 
to holes 48. In a preferred embodiment, the bottoms of holes 48 are 
positioned at generally one-half the distance d above the upper surface of 
recess wall 24. 
It will be appreciated that valves of different configuration may require a 
different relative spacing of components of cleaning nozzle 10, differing 
from that shown and described above. However, it is generally preferred 
that the holes 48 be located outside of the holes 44 and that the holes 48 
be located above the recess wall 24 in which holes 44 are formed. 
As will be seen herein, nozzle 10 can accommodate different types of 
cleaning media flows, without requiring modification. For example, the 
cleaning media entering hole 34 may come from a variety of sources. For 
example, cleaning media may pass through a pump 60 which provides a steady 
pressurized flow of cleaning media entering chamber 30. Alternatively, 
cleaning media may pass through a pump 62 which pulsates the pressurized 
flow of cleaning media, sending pulses or spaced waves of cleaning media 
into chamber 30. FIG. 8 illustrates, in schematic form, the pulsating 
operation of nozzle 10, described above, with waves of cleaning media 
impacting surface 58 of dispense valve 12. Accordingly, the cleaning flow 
impinging on valve surface 58 may either be a steady flow, or may be 
pulsating. In an alternative arrangement, cleaning media may be drawn from 
inlet conduit 66 by suction forces created by vacuum pump 64. In either 
event, cleaning spray is ejected from evacuation chamber 38 by a vacuum 
pump 64. As seen above, the cleaning nozzle 10 is formed from a minimum 
number of inexpensive components, and can be quickly and easily serviced, 
if necessary, especially since it contains no moving parts. Turning now to 
the arrangement of FIGS. 3 and 4, an alternative embodiment of a cleaning 
nozzle is generally indicated at 80. Cleaning nozzle 80 is essentially 
identical in construction to cleaning nozzle 10, except for the recess 
wall, indicated by the referenced numeral 82 in the figures. As can be 
seen in FIG. 4, the recess wall 82 is separated from the standoff 28 and 
the sidewall 22, being freed for rotation about the center axis of the 
cleaning nozzle 80. Recess wall 82 is mounted by bearings 86 to the upper 
end of entry chamber 30, at a point adjacent to joinder of standoff 28 and 
sidewall 22, thereby reducing frictional losses which might otherwise 
impair the free rotation of the recess wall. A plurality of turning vanes 
90, generally resembling turbine blades, are located on the underneath 
surface of recess wall 82. A portion of the flow entering holes 44 from 
entry chamber 30 impinges on turning vanes 90, thereby rotationally 
driving recess wall 82 in the direction shown by arrows 92 in FIG. 3. 
Thus, a rotational velocity is imparted to flow exiting holes 44, creating 
a swirl pattern within recess 20. 
Turning now to FIGS. 5 and 6, cleaning nozzle 100 is substantially 
identical to cleaning nozzle 80 described above, except for the addition 
of upstanding bristles 102 attached to the upper surface of recess wall 
82. The bristles may take other forms, conventionally available, other 
than that shown in the figures, and a smaller or larger number of bristles 
may be employed. Further, the bristles could be replaced by a sponge pad 
riding atop the surface of recess wall 82, substantially filling the space 
between recess wall 82 and the surface 58 of the dispense valve 12. The 
sponge will become loaded with cleaning media and thereby provide cleaning 
media contacting surface 58 of dispense valve 12. Alternatively, the 
sponge could be perforated to allow spray to impact the surface 58. 
Further, bristles 102 could be replaced by other mechanical cleaning 
media, such as an abrasive screen, or a fiber pad, conventionally 
available for such purpose. 
Turning now to FIGS. 7a-7e, a cleaning cycle according to principles of the 
present invention will be described. As shown in FIG. 7a, a vacuum is 
initially drawn in cleaning nozzle 10 under the force of vacuum pump 64 
which is shown in FIG. 2. The gasket 50 preferably forms an hermetic seal 
with respect to dispense valve 12, so as to create an hermetically sealed 
chamber surrounding the recess 20. As will be seen herein, it is generally 
preferred that cleaning nozzle 10 be mechanically raised in position 
against valve 12. This alone may be relied upon to provide the necessary 
hermetic seal between gasket 50 and valve 12. However, the negative 
pressure applied to the interior of the cleaning nozzle could also be 
relied upon for this purpose. 
As a next step in the cleaning operation illustrated in FIG. 7b, cleaning 
media enters chamber 30. The cleaning media may either be pressurized or 
may be drawn by suction by an external vacuum source, such as the vacuum 
pump 64 illustrated in FIG. 2. In either event, FIG. 7b shows the initial 
entry of cleaning media into chamber 30. During this time, a vacuum 
continues to be applied to exit hole 40. FIG. 7c shows a later stage of 
operation, with cleaning media being passed through holes 44, so as to 
contact the valve 12. As described above, cleaning media passes through 
holes 48 so as to exit cleaning nozzle 10 through hole 40. 
After the dispense valve is sufficiently cleaned, the flow of cleaning 
media entering chamber 30 is shut off while a vacuum continues to be 
applied through exit hole 40. At the moment of time illustrated in FIG. 
7d, a vacuum continues to be applied to exit hole 40 so as to withdraw 
cleaning media filling recess 20. As mentioned above, it is preferred that 
the holes 48 be spaced above the recess wall 24 and accordingly a layer of 
cleaning media remains atop recess wall 24. Increasing the vacuum applied 
to the cleaning nozzle will draw down a certain amount of cleaning media, 
but may not be sufficient to completely withdraw all cleaning media from 
the cleaning nozzle. This may become important, for example, when the same 
cleaning nozzle is used with incompatible cleaning media, or when 
contamination of later applied cleaning media is to be avoided. 
Accordingly, as illustrated in FIG. 7e, a negative pressure or a vacuum is 
applied to entrance aperture 34. For example, one of the pumps 62, 
illustrated in FIG. 2, can be reversed to draw a vacuum through the 
cleaning nozzle 10. As shown in FIG. 7e, vacuum continues to be drawn 
through exit aperture 40, although this negative pressure may be lessened 
or removed to ensure that vacuum drawn at entrance aperture 34 
successfully withdraws cleaning media which puddles atop the recess wall 
24, and which may cling to the walls of chamber 30. 
Referring to FIG. 9, liquid cleaning media enters conduit 110, while air or 
other material combines with the flow, under controlled operation of 
regulator 112. The combined flow then enters cleaning nozzle 10. In the 
preferred embodiment, air is injected into liquid cleaning media to 
provide the desired momentum impinging on the dispense valve surface. 
Although air injection reduces the mass of the mixture impinging on the 
dispense valve, the velocity imparted to the mixture can be readily 
increased, and the flow characteristics of the mixture through the holes 
44 can be rendered more favorable. In addition, favorable cleaning can be 
obtained with a substantial savings on cleaning material. 
In FIG. 10 a cleaning system generally indicated at 120 includes a 
conventional multi-section valve 122 which controls the flow of cleaning 
solution entering and leaving cleaning nozzle 10. Operation of valve 122 
is schematically illustrated in FIG. 11. As indicated in FIGS. 7 and 11, 
cleaning solution may be drawn from a plurality of different sources 
124a-124c. Valve 122 can direct flow into cleaning nozzle 10 through any 
one of the sources 124a-124c. Also, flow exiting cleaning nozzle 10 can be 
directed to any one of the sources 124a-124c, as desired. As indicated in 
solid lines in FIG. 11, one example of operation of valve 122 is shown, 
with material being drawn from and returning to the same source 124c. 
However, with cleaning valve 122, cleaning solution drawn from sources 124c 
can, after passing through cleaning nozzle 10, be directed to a different 
source, such as source 124b. Further, valve 122 can be made to operate in 
sequence, first drawing solution from source 124a, returning the solution 
to that source. After the cleaning nozzle has been purged of cleaning 
solution from source 124a, valve 122 can direct cleaning solution from 
source 124b, returning the solution to source 124b. After the cleaning 
nozzle is purged of solution from source 124b, solution from source 124c 
can thereafter be routed through cleaning nozzle 10 by valve 122. 
Further cleaning operations are possible with the present invention. For 
example, a cleaning system generally indicated at 130 is illustrated in 
FIG. 12. In this embodiment, cleaning solution is drawn from source 124a, 
being routed through valve 122 to enter cleaning nozzle 10. The cleaning 
solution exiting cleaning nozzle 10 is directed to a second cleaning 
source 124b, and does not return to source 124a. As indicated 
schematically in FIG. 12, cleaning solutions may be passed through 
cleaning nozzle 10 in batches. One important commercial application 
pertains to the cleaning of dispensing nozzles which deliver offset 
printing inks, especially such inks which have particularly strong 
coloring agents. For example, the arrangement of FIG. 12 can be used to 
clean a first valve with fresh cleaning solution. The first batch of 
cleaning solution exiting dispense nozzle 10 will be particularly dirty, 
and oftentimes will have elevated levels of grit suspended in the 
solution. This first batch of cleaning solution may be retained for other 
uses, or may be discarded. Thereafter, a second batch of cleaning solution 
can be circulated through dispense nozzle 10, being retained in a 
different receptacle. This somewhat cleaner solution can be reused in the 
initial cleaning stages for another dispense valve, for example. 
Turning now to FIGS. 13-17, a cleaning system according to principles of 
the present invention, is generally indicated at 200. The cleaning system 
is shown mounted beneath a dispense system generally indicated at 202. The 
dispense system 202 includes a plurality of dispense valves 204 mounted on 
a movable tray 206 so as to be selectably positioned under a stationary 
actuator 208 having a jaw 210 for engaging the upper ends of the dispense 
valves. As indicated by arrow 214, jaw 210 is movable up and down to 
operate the dispense valve 204. The dispense valves 204 have dispense 
nozzles 220 from which material emerges for passage to a receptacle 
located below, not shown in the figures. 
Referring to the bottom plan view of FIG. 15, tray 206 is mounted for 
movement in a plane, located underneath actuator 208. The arrangement for 
moving tray 206 is conventional, being sometimes termed an "X-Y table". In 
this arrangement, tray 206 is mounted on rails 224 and is driven by 
actuator 226 for movement in a direction of arrows 228. Actuator 226 is 
preferably pneumatic, but may also be hydraulic or electrically operated. 
Tray 206 is also movable in a perpendicular direction, being mounted on 
rails 232 for movement by actuator 234 in a direction of arrows 236. In a 
preferred embodiment shown in the figures, sixteen dispense valves are 
mounted on tray 206, and any one of the 16 valves can be indexed so as to 
be positioned underneath the stationery actuator 208. 
A cleaning nozzle 10 is carried on a separate "X-Y table" for movement in a 
plane parallel to the plane of movement of tray 206. Cleaning nozzle 10 is 
mounted on a table 250 (see FIG. 15) which in turn is mounted on rails 252 
for movement in a direction of arrows 254. Rails 252 are in turn mounted 
on rails 258 for movement in direction of arrows 260. Power for driving 
table 250 on rails 252, 258 may be provided by any suitable conventional 
means, such as a belt system traveling along the rails, driven by 
actuators 264, 266, respectively. 
The aforementioned actuators are coupled by electrical conductors to a 
conventional programmable logic controller or similar control device. The 
device can independently control movement of tray 206 and table 250, but 
preferably coordinates their movements in the following manner. A desired 
dispense valve mounted on tray 206 is moved into position under actuator 
208 and a desired dispensing operation is completed. Thereafter, the 
control device determines which dispense valve is to be positioned next, 
underneath actuator 208 and plans a path for movement of tray 206. The 
control device then operates actuators 264, 266 so as to move table 250 
along the same path, so that cleaning nozzle 10 can follow directly 
underneath the last dispensed valve as it moves away from actuator 208. 
During this time, a cleaning nozzle is moved into contact with a dispense 
valve in a manner indicated in FIGS. 16 and 17. Referring now to FIGS. 16 
and 17, a plurality of solenoid actuators 274 are mounted on table 250 so 
as to move the cleaning nozzle 10 up and down in the direction of arrows 
276. 
As a dispense valve is either located at the dispense position or recently 
moved away from actuator 208, cleaning nozzle 10 is brought underneath the 
dispense valve and, under control of the control device, the cleaning 
nozzle is raised into position, being seated against the dispense valve. 
Cost savings may be obtained if the control system is required only to 
"home" the cleaning nozzle at a point underneath the dispense nozzle. The 
cleaning cycle is then initiated and preferably completed while tray 206 
is being indexed to bring the next dispense valve underneath actuator 208, 
and if necessary, while a second dispensing operation is being carried 
out. Thereafter, solenoids 274 are controlled by the control device and 
actuators 264, 266 are operated by device to position the cleaning nozzle 
10 under the dispense valve which has most recently completed a dispensing 
operation. In this manner, dispensing operations need not be halted for 
valve cleaning. The actuators 264, 266 could also be of the pneumatic or 
hydraulic type if desired. 
The cleaning nozzle 10 has been described above with respect to a single 
cleaning valve. However, the present invention is also directed to use of 
cleaning valves which service a dispense head, having multiple discharge 
nozzles. Referring to FIGS. 18 and 19, a dispense head 300 has a plurality 
of incoming conduits 302 terminating in a plurality of dispense nozzle 
304. The dispense head 300 has a sidewall 310 which preferably includes a 
lower beveled corner. The cleaning nozzle 10 is the same as that described 
above with reference to FIGS. 1 and 2 and the cleaning operations carried 
out with nozzle 10 are the same as those described above. It will be 
readily appreciated that cleaning nozzle 10 can be reconfigured in size 
and shape to accommodate a wide variety of dispense valves. 
The drawings and the foregoing descriptions are not intended to represent 
the only forms of the invention in regard to the details of its 
construction and manner of operation. Changes in form and in the 
proportion of parts, as well as the substitution of equivalents, are 
contemplated as circumstances may suggest or render expedient; and 
although specific terms have been employed, they are intended in a generic 
and descriptive sense only and not for the purposes of limitation, the 
scope of the invention being delineated by the following claims.