U.S. patent number 3,690,518 [Application Number 05/089,381] was granted by the patent office on 1972-09-12 for modular applicator system.
This patent grant is currently assigned to Nordson Corporation. Invention is credited to Robert G. Baker, Samuel R. Rosen.
United States Patent |
3,690,518 |
Baker , et al. |
September 12, 1972 |
MODULAR APPLICATOR SYSTEM
Abstract
A fluid operated system of modular guns for extruding or
spraying liquids such as molten adhesives. The system includes
multiple guns in the form of readily removable cylindrical modules
that mount in apertures of a fixed service block or manifold which
receives the supply lines for the liquid and the gun operating
pressurized fluid. The service block and guns have passages which
register when the system is assembled whereby the guns may be
easily removed from the fixed service block and replaced without
disconnecting any fluid lines or other service equipment.
Inventors: |
Baker; Robert G. (Avon, OH),
Rosen; Samuel R. (Lorain, OH) |
Assignee: |
Nordson Corporation (Amherst,
OH)
|
Family
ID: |
22217347 |
Appl.
No.: |
05/089,381 |
Filed: |
November 13, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
776177 |
Nov 15, 1968 |
3570725 |
|
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|
Current U.S.
Class: |
222/504;
222/559 |
Current CPC
Class: |
B05C
5/0275 (20130101); B05C 5/001 (20130101); B65B
51/023 (20130101); B05C 5/0237 (20130101) |
Current International
Class: |
B05C
5/00 (20060101); B65B 51/02 (20060101); B05C
5/02 (20060101); B65B 51/00 (20060101); G01f
011/06 () |
Field of
Search: |
;222/275,504,510,330,132 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tollberg; Stanley H.
Parent Case Text
This application is a continuation-in-part application of our
copending application Ser. No. 776,177 filed Nov. 15, 1968, now
U.S. Pat. No. 3,570,725 entitled "Modular Adhesive Applicator,"
which application is assigned to the assignee of this application.
Claims
1. A modular apparatus for emitting a liquid from a pressurized
source onto a substrate comprising
a service block module having essentially only static parts and
defining a first passage for a liquid, and a second passage for a
gun actuating pressurized fluid, said module having at least one
aperture intersecting said passages,
a readily removable gun module including a body mounted in said
aperture of said service block module,
said gun module including a nozzle,
said gun module including essentially all the movable parts of said
apparatus, said gun module body defining a first passage for liquid
communicating between said liquid passage in said service block
module and said nozzle, said first passage in said gun module body
being in sealing registration with said liquid passage in said
service block module when said modules are in assembled relation,
said gun module body also defining a second passage for pressurized
fluid communicating between said pressurized fluid passage in said
service block module, said pressurized fluid passages of said gun
module and service module also being in sealing registration when
said modules are in assembled relation,
a movable valve element in said gun module for opening and closing
liquid flow through said nozzle, and
movable means in said gun module responsive to connection with said
pressurized fluid for operating said valve.
2. The modular apparatus of claim 1 which further includes multiple
apertures intersecting said service block module passages and a
readily removable modular gun mounted in each of said
apertures.
3. The modular apparatus of claim 1 in which said gun module body
is generally cylindrical in configuration and in which said
aperture is circular in cross section, said aperture having
internal threads and said gun module body having external threads
threaded into said threaded aperture so as to removably mount said
gun module in said aperture.
4. The modular apparatus of claim 2 which further includes spring
means for biasing each of said valve elements of each of said gun
modules to a closed position and adjustable preload means for
adjusting the spring tension operable to maintain said valve
elements in a closed position, said adjustable preload means
enabling the several gun modules to be adjusted to equalize the
pressure required to open each gun module.
5. The modular apparatus of claim 4 which further includes means to
adjust the stroke of each of the movable valve elements of each of
the gun modules, said stroke adjustment means being independent of
said preload adjustment means in each of said gun modules.
6. The modular apparatus of claim 1 in which the said gun module
body is generally cylindrical body and has a through bore extending
axially therethrough, a portion of said body being externally
threaded so as to enable said body to be threaded into a threaded
section of said aperture of said service block module, the axial
bore of said cylindrical body being internally threaded at its
opposite ends, said nozzle being threaded into said bore at one end
and a closure cap threaded into the threaded bore at the opposite
end.
7. The modular apparatus of claim 6 in which a portion of said
axial bore defines a fluid cylinder in said gun module at one end
of said cylindrical body and another portion of said axial bore
defines a liquid chamber at the opposite end of said body, said
first passage of said gun module communicating with said fluid
cylinder and said second passage of said gun module communicating
with said liquid chamber.
8. The modular apparatus of claim 7 in which said movable means
includes a piston slideable in said cylinder and which further
includes spring means operable between said piston and said closure
cap to bias said piston and said movable valve element to a closed
position.
9. A modular apparatus for ejecting a liquid from a pressurized
source onto a substrate, comprising
a fixed service block module having essentially only static parts
and defining a passage for liquid and a passage for pressurized
operating fluid, said service block module having at least one
aperture intersecting said passages,
a readily removable gun including a body removably mounted in said
aperture of said service block module,
said gun module including a nozzle,
means defining a fluid cylinder in said gun module body,
a piston in said fluid cylinder,
said gun module body containing essentially all the movable parts
of said apparatus and defining a first passage communicating
between said liquid passage in said service block module and said
nozzle and a second passage communicating between said fluid
passage in said service block module and said fluid cylinder, said
first and second passages of said body being in sealing
registration with their respective passages in said service block
module when said modules are in assembled relation, and
a movable valve element in said gun module operatively connected to
said piston for opening and closing liquid flow through said
nozzle.
10. The modular apparatus of claim 9 which further includes
multiple apertures intersecting said service block passages and a
readily removable modular gun mounted in each of said
apertures.
11. The modular apparatus of claim 9 in which said gun modules body
is generally cylindrical in configuration and in which said
aperture is circular in cross section, said aperture having
internal threads and said gun module body having external threads
threaded into said threaded aperture so as to removably mount said
gun module body in said aperture.
12. The modular apparatus of claim 10 which further includes spring
means for biasing each of said valve elements of each of said gun
modules to a closed position and adjustable preload means for
adjusting the spring tension operable to maintain said valve
elements in a closed position, said adjustable preload means
enabling the several gun modules to be adjusted to equalize the
pressure required to open each gun module.
13. The modular apparatus of claim 12 which further includes means
to adjust the stroke of each of the movable valve elements of each
of the gun modules, said stroke adjustment means being independent
of said preload adjustment means in each of said gun modules.
14. The modular apparatus of claim 9 in which the said gun module
body is generally cylindrical and has a through bore extending
axially therethrough, a portion of said body being externally
threaded so as to enable said body to be threaded into a threaded
section of said aperture of said service block module, the axial
bore of said cylindrical body being internally threaded at its
opposite ends, said nozzle being threaded into said bore at one end
and a closure cap threaded into the threaded bore at the opposite
end.
15. The modular apparatus of claim 14 in which a portion of said
axial bore defines said fluid cylinder in said gun module at one
end of said cylindrical body and another portion of said axial bore
defines a liquid chamber at the opposite end of said body, said
first passage of said gun module body communicating with said fluid
cylinder and said second passage of said gun module body
communicating with said liquid chamber.
16. The modular apparatus of claim 15 which further includes spring
means operable between said piston and said closure cap to bias
said piston and said movable valve element to a closed
position.
17. The modular apparatus of claim 16 which further includes
adjustable preload means for adjusting the spring tension operable
to maintain said valve element in a closed position.
18. The modular apparatus of claim 17 which further includes means
to adjust the stroke of said movable valve element, said stroke
adjustment means being independent of said preload adjustment
means.
19. A modular apparatus for ejecting a liquid from a pressurized
source onto a substance, comprising
a fixed service block module having essentially only static parts
and defining a passage for liquid and a passage for pressurized
operating fluid, said service block module having multiple
apertures intersecting said passages,
a readily removable gun module mounted in each of said apertures of
said service block module,
each of said gun modules including a nozzle,
means defining a fluid cylinder in each of said gun modules,
a piston in each of said fluid cylinders,
said gun modules including essentially all the movable parts of
said apparatus and defining a first passage communicating between
said liquid passage in said service block module and said nozzle
and a second passage communicating between said fluid passage in
said service block module and said fluid cylinder, said first and
second passages of each of said gun modules being in sealing
registration with their respective passages in said service block
module when said modules are in assembled relation, and
a movable valve element in said gun module operatively connected to
said piston for opening and closing liquid flow through said
nozzle.
20. The modular apparatus of claim 19 in which each of said gun
modules is generally cylindrical in configuration and in which said
apertures are circular in cross section, said apertures having
internal threads and said gun modules having external threads
threaded into said threaded apertures so as to removably mount said
gun modules in said apertures.
21. The modular apparatus of claim 19 which further includes spring
means for biasing each of said valve elements of each of said gun
modules to a closed position and adjustable preload means for
adjusting the spring tension operable to maintain said valve
elements in a closed position, said adjustable preload means
enabling the several gun modules to be adjusted to equalize the
pressure required to open each gun module.
22. The modular apparatus of claim 21 which further includes means
to adjust the stroke of each of the movable valve elements of each
of the gun modules, said stroke adjustment means being independent
of said preload adjustment means in each of said gun modules.
23. The modular apparatus of claim 19 in which each of the said gun
modules comprises a generally cylindrical body having a through
bore extending axially therethrough, a portion of said body being
externally threaded so as to enable said body to be threaded into a
threaded section of one of said apertures of said service block
module, the axial bore of said cylindrical body being internally
threaded at its opposite ends, said nozzle being threaded into said
bore at one end, and a closure cap threaded into the threaded bore
at the opposite end.
24. The modular apparatus of claim 23 in which a portion of said
axial through bore of each of said bodies defines said fluid
cylinder at one end of said cylindrical body and another portion of
said axial bore defines a liquid chamber at the opposite end of
said body, said first passage of said gun module communicating with
each of said fluid cylinders and said second passage of said gun
module communicating with said liquid chamber.
25. The modular apparatus of claim 24 which further includes spring
means operable between each of said pistons and said closure caps
to bias said pistons and said movable valve elements to a closed
position.
26. The modular apparatus of claim 25 which further includes
adjustable preload means for adjusting the spring tension operable
to maintain each of said valve elements of each of said gun modules
in a closed position.
27. The modular apparatus of claim 26 which further includes means
to adjust the stroke of said movable valve elements of each of said
gun modules, said stroke adjustment means being independent of said
preload adjustment means.
Description
This invention relates to the application of liquids to surfaces
and especially to equipment used to apply beads, ribbons or small
unitary deposits of extruded or sprayed material in a desired
pattern under high speed production conditions. More particularly,
the invention relates to equipment which is particularly suitable
for applying heated liquids such as "hot melt" molten adhesives to
various materials such as flat sheets or webs of paper or cardboard
of the type commonly used in packaging and adhering a variety of
products. The invention, though, is equally applicable to the
application of other liquid materials such as coating materials and
paints which may be applied cold or at room temperature.
"Hot melt" liquids are typically of the asphaltic or synthetic
resin type and are generally in their solid state at room
temperature. When heated to molten form, however, they change in
physical state to a relatively viscous liquid which may be pumped
through the nozzle of an applicator tool or gun and applied to a
surface in the form of a continuous bead or ribbon or as
intermittent deposits. Normally, such hot melt materials are
converted to a molten state in a heater and then transmitted to
applicator guns under pressure through heated lengths of flexible
hose. The applicator guns are preferably heated also to assure that
the adhesive remains in molten form until it leaves the nozzles of
the guns.
In many high speed packaging applications, the molten or liquid
"hot melt" is applied to moving sheet material such as a web of
paper or flattened cardboard cartons. In other applications the
"hot melt" is applied to filled containers prior to the sealing of
the flaps or an end closure. In still other applications, the
molten material is used in the coating or assembly of parts.
Certain types of applicator guns used for application of hot melt
adhesives as well as the application of other liquids are operated
by means of fluid cylinders which open and close a valve in the
molten liquid feed line and thus interrupt the extrusion or
expulsion of the liquid from the nozzle of the gun. Where air
operated guns are used it is necessary, of course, to use an air
pressure line from a pressure source. Also, since the body of the
gun is normally heated to maintain the liquid in a molten or low
viscosity state, it is essential that electrical service lines also
be connected to the gun.
A problem encountered with this type of equipment, particularly in
the application of hot melt adhesive but also in the application of
other liquid materials, has been the time consuming cleaning
operation which must be accomplished at periodic intervals. The
cleaning requires the removal of all of the fluid lines and other
service lines from the gun and afterward the reconnection of the
lines as well as the careful repositioning of the gun so as to
extrude the beads of liquid at a proper predetermined location. All
this is quite time consuming and requires the interruption of a
continuous production facility at frequent intervals.
It has therefore been an objective of this invention to
substantially reduce or eliminate the difficulties encountered in
cleaning or replacing applicator guns.
Another objective of this invention has been to reduce the number
of supply lines and service lines required to supply a plurality of
guns used to apply viscous liquids, such as molten adhesives, to
translating packaging materials or the like.
Still another object has been to reduce the time needed to remove
and replace an extrusion gun from a fixed mount in a system for
applying liquid coating and extrusion materials wherein the gun
must be frequently cleaned.
These and other objects are accomplished by a modular apparatus
with a fluid or air type operating system and a pumping system for
the viscous liquid to be extruded or sprayed, the apparatus
including a fixed service module or manifold defining a passage or
manifold for the viscous liquid and a passage or manifold for
operating fluid. The passage for the viscous liquid communicates
with the pumping system and the passage for operating fluid
communicates with a fluid pressure line. One or more removable gun
modules are mounted in the fixed service block module. Each gun has
a passage communicating between the viscous liquid passage in the
service block module and an extrusion nozzle, and a passage for
operating fluid communicating between the operating fluid passage
in the service block and a fluid cylinder. The guns are cylindrical
and have threads for mounting in the service module so that the
guns may be readily removed from the service module for service or
replacement without disturbing the connections to the service
module (air line, electrical lines and hydraulic lines.) Multiple
guns may be mounted in the service module in a random pattern (not
necessarily in a straight line or geometrical pattern, nor
necessarily parallel to each other) so that a pattern of adhesive
or other material can be applied to a product or a substrate to
fulfill any pattern requirement. Each gun consists of a cylindrical
body which contains a ball valve, located in a chamber which is
filled with the viscous liquid when the gun is in operation. The
valve is opened by a rod which is attached to the ball and passes
through a seal which separates the liquid material from an
atmospheric vent chamber. The rod continues through a second seal
located between the vent chamber and an air cylinder where the rod
is attached to a piston. By applying pressurized fluid, as for
example air, to the piston the ball is pulled from the valve seat
allowing material to flow out of the gun onto the product or
substrate. When the pressure is removed from the piston a spring
returns the ball to its closed position on the valve seat. An
adjustment is provided on the return spring so that the amount of
fluid pressure required to actuate the gun is adjustable. Since the
force required to actuate each individual gun varies because of
differing internal gun fiction forces, the adjustable preload of
the spring allows several guns to be adjusted to equalize the
pressure required to open each gun. Thus each gun may be adjusted
to open at the same time. This is particularly desirable when the
product or substrate is moving and registration of the pattern is
required.
In the preferred embodiment a heater is provided in the service
module to maintain the liquid in a molten or low viscosity state
until after it leaves the nozzle of the gun.
The primary advantage of this modular applicator system is the ease
with which it enables multiple modular guns to be arranged in
random, closely spaced patterns. The patterns may have points of
application spaced as closely as the diameter of a single gun and
may be arranged or configurated in any pattern in which gun
receiving holes may be drilled or machined into the service module
or block.
Another advantage of this invention is the miniturization which it
facilitates. Guns constructed in accordance with this invention may
be manufactured relatively inexpensively in small sizes or in small
diameter cylindrical housings. These small size guns in turn may be
used in applications where larger guns would not fit and could not
be accommodated .
These and other objects and advantages of this invention will be
more readily apparent from the following description of the
drawings in which:
FIG. 1 is a cross sectional view through a modular system
incorporating the invention of this application.
FIG. 2 is a cross sectional view through the service module taken
on line 2--2 of FIG. 1.
FIG. 3 is an enlarged cross sectional view through a gun module
taken on line 3--3 of FIG. 1.
Referring first to FIG. 1, there is illustrated a four-gun
applicator system 10 for applying a heated liquid material to a
substrate. In the illustrated embodiment the four gun modules or
guns 11, 12, 13 and 14 are mounted in alignment in a service module
or service block 15. The guns could, though, be mounted out of
alignment or in any pattern in the service module 15 but for ease
of illustration they are shown in linear alignment.
The service module 15 comprises a generally rectangular block
through which there extends a pressurized fluid or air passage 16
and a parallel liquid flow passage 17. In the preferred embodiment
there is also an atmospheric vent passage 18 extending parallel to
and located between the two other passages 16 and 17. These three
transverse passages are intersected by four gun mounting apertures
20, 21, 22 and 23 which are perpendicular to the passages 16-18.
The apertures 20-23 are step bored for reception of the guns 11-14
respectively and each includes a small diameter end section 24, a
larger diameter section 25, a still larger diameter middle section
26 and a large diameter end section 27. A portion of the large
diameter end section 27 is threaded, as indicated at 28, for
reception of a threaded end section of a modular gun, as is
explained more fully hereinafter.
In applications in which the system is intended to be used to apply
hot melt or heated materials, the service module or block 15
includes a transverse bore 30 within which there is mounted an
electrical resistance heater 31. The flow of electrical current
through this heater 31 is controlled by a thermostat 32 mounted in
a recess 33 in the face of the block 15. The recess is covered by a
plate 34 bolted or otherwise secured to the service module so as to
enclose the thermostat containing recess 33.
The service module may be mounted at an applicator station in any
convenient manner. In the illustrated embodiment the service block
15 is secured to a mounting bracket 38 by bolts 39. The mounting
bracket is in turn slideable over a bar 40 to which it is secured
by a locking screw 41.
The four gun modules 11-14 are identical and therefore only one is
illustrated and described in detail. As may be seen most clearly in
FIGS. 1 and 3, the gun modules are generally circular and tubular
in configuration for mounting in the circular cross section
apertures 20-23 of the service module. Each gun includes a tubular
body 45 through which there extends an axial bore 46. This bore
defines a high pressure fluid or air cylinder 47 at one end and a
liquid chamber 48 at the opposite end. A small diameter section 49
of the bore interconnects the cylinder 47 and chamber 48.
The bore 46 of the body is closed at one end by an end closure cap
50 threaded into an internally threaded end 51 of the bore 46. The
opposite end of the bore 46 in the body 45 is similarly closed but
by a nose piece 53 threaded into an internally threaded end section
54 of the body.
A stepped axial bore 55 extends through the nose piece 53. The
larger diameter section of this bore 55 defines a chamber 56 which
is open to the liquid chamber 48 of the body. This latter chamber
56 communicates with a small diameter port 57 which is open to the
end of the gun. In the illustrated embodiment, the nozzle 59 of the
gun is threaded onto the end of the nose piece 53.
An internal shoulder of the nozzle 53 at the intersection of the
small diameter bore 57 and the larger diameter chamber 56 forms a
valve seat 63 for a ball valve 64. This ball valve 64 and valve
seat 63 together form a check valve 65 for controlling flow of
pressurized liquid from the liquid chambers 56 and 48 of the gun.
Liquid is supplied to these chambers through a transverse passage
66 in the body 45 of the gun. When the gun is assembled in the
service module or service block 15, this passage 66 registers with
the transverse liquid supply passage 17 through which liquid, as,
for example, hot melted adhesive, is supplied to the system 10 at
high pressure, as, for example, 400 pounds per square inch.
The ball valve 64 is mounted upon one end of a piston rod 68. This
rod extends upwardly through the small diameter section 49 of the
bore 46 and at the opposite end terminates in a threaded section
69. A piston 70 is mounted upon the threaded section 69 of the rod.
This piston comprises four stacked rings 71-74. The upper one 74
and the lower one 71 of these rings are threaded onto the section
69 of the rod 68 so as to facilitate adjustment of the piston on
the rod. This adjustment of the piston enables the stroke of the
check valve to be adjusted by varying the distance the piston is
movable from a valve closed position to a position in which the top
87 of the piston 70 contacts the bottom surface 88 of the closure
cap 50.
An air seal, preferably a Teflon seal, 75 is sandwiched between the
two middle rings 72 and 73 of the piston. This seal 75 prevents the
escape of air pressure from the high pressure cylinder 47 located
beneath the piston to a low pressure chamber 76 in the closure cap
50. This latter chamber 76 is maintained at atmospheric pressure
through a transverse passage 77 in the cap 50 which opens to
atmosphere.
An adjustable preload spring 80 is located in the chamber 76 of the
closure cap and bears against one side of the piston 70 so as to
force the piston and the ball valve 64 to a closed position. The
opposite end of this spring 80 bears against an adjustable seat 81
which is slideable in the chamber 76 of the closure cap. This seat
81 rests against an end 82 of a preload adjustment screw 83. The
screw is threaded through a threaded aperture 84 of the closure cap
50 and is secured in an adjusted position by a lock nut 85. By
adjusting the screw 83 and thus the axial position of the seat 81,
the force holding the valve closed and thus the force required to
open the valve may be adjusted. This adjustment enables air
pressure required to open several guns to be equalized even though
the internal friction of the individual guns may be different.
Air pressure in cylinder 47 controls opening and closing of the
check valve 65. This pressure, generally in the form of air
pressure, is supplied to the cylinder 47 through a transverse
passage 86 which registers with the passage 16 in the service
module. High pressure air supplied to the passage 16 effects
opening of the check valves by causing the pistons of the guns to
move upwardly until the tops 87 of the pistons engage the bottom
edge 88 of the caps 50. When the pressure in the passage 16 is
released or opened to atmosphere, the springs 80 effect closing of
the valves.
In order to prevent leakage of air pressure from the chamber 47
through the bore 49 and to prevent leakage of liquid from the
chamber 48, an air seal 90 is provided around the rod 68 in the air
cylinder 47 and a liquid seal 91 is provided around the rod 68 in
the liquid chamber 48. The seal 90 includes a resilient Teflon
washer 92 held in place by a spring washer 93. The liquid or
hydraulic seal 91 also includes a resilient Teflon washer 94 but
this seal is held in place by a washer 95 and a backing spring 96.
At one end the spring bears against the washer 95 and at the
opposite end it bears against an end surface 97 of the nozzle 53.
To further insure that liquid does not leak into the air cylinder,
a transverse vent aperture 98 is provided in the body 45
intermediate to the seals 90 and 91. This vent 98 is connected to
the through passage 18 in the service module so that it is always
open to atmosphere.
OPERATION
The four guns 11-14 are individually threaded into the service
module and when so assembled, the air passages 86 of the guns
register the air passage 16 of the service module. Similarly, the
liquid passages 66 register with the liquid passage 17 of the
service module and the atmospheric vents 98 register with the
atmospheric vent 18 of the service module. Air is prevented from
leaking around the exterior of the gun from the passage 16 to the
passage 18 by O-ring seals 100 which are mounted in grooves 101 in
the exterior of the bodies 45. Two other O-rings 102 and 103 are
mounted in grooves 104 and 105 in the bodies 45 to prevent liquid
from leaking around the exterior of the body from the liquid
passage 17 of the service module.
The individual guns are so adjusted by the preload adjustment screw
83 that all four open simultaneously when air pressure is supplied
to the gun through the passage 16 of the service module. This air
pressure causes the pistons 70 of the guns to move upwardly until
the top surfaces 87 of the pistons contact the bottom surfaces 88
of the closure caps 50. This upward movement of the pistons effects
the upward movement of the check ball valves 65 and permits liquid
supplied to the guns at high pressure (as, for example, 400 psi) in
passage 17 to pass through and out of the liquid chambers 55 via
the nozzle ports 57. The strokes of the guns are preadjusted prior
to assembly of the guns by locating the pistons 70 on the piston
rods 68 so that the liquid flows at the proper rate through the
check valve 65. After the liquid material has been deposited upon a
substrate, the air pressure in passage 16 is opened to atmosphere
and the guns are caused to close as a result of the springs 80
forcing the pistons and the attached check valves to a closed
position.
When it is necessary to clean one of the guns or if foreign matter
should cause a gun to break, the service lines to the service
module 15 need not be disconnected from the service module.
Specifically, the air line to the passage 16, the fluid line to the
passage 17 and the electric lines to the heater 31 and thermostat
32 need not be disconnected. All that is required is for the lines
to be closed or shut off and the clogged or broken gun to be
removed by unthreading it from the mounting aperture of the service
module. A new gun may then be inserted by threading it into the
aperture and the system restarted. The clogged or broken gun may
then be cleaned or repaired without closing down any production
facilities while this cleaning or repair takes place.
While we have described only a single preferred embodiment of the
invention, persons skilled in the art to which this invention
pertains will readily appreciate changes and modifications which
may be made without departing from the spirit of our invention.
Specifically, the modular guns may be arranged in any kind of
random pattern in a mounting block and may be angulated relative to
each other so as to locate the deposits from the gun in even closer
spacing than the spacing of the gun nozzle orifices. Additionally,
the system has been specifically described as applied to a hot melt
application and including a heated service module. The invention is
equally applicable, though, to unheated liquid applications.
Therefore, we do not intend to be limited except by the scope of
the appended claims. Having described our invention, we claim:
* * * * *