Method and apparatus for applying a material to a web

A method and apparatus of manufacturing a web which is striped with add-on material, comprising: a first arrangement which establishes a sheet of base web from a first slurry and moves the established sheet along a first path; a second arrangement for preparing a second slurry; a moving orifice applicator operative so as to repetitively discharge the second slurry upon the moving sheet of base web, the moving orifice applicator comprising: a chamber box arranged to establish a reservoir of the second slurry across the first path; an endless belt having an orifice, the endless belt received through the chamber box; a drive arrangement operative upon the endless belt to continuously move the orifice along an endless path and repetitively through the chamber box, the orifice when communicated with the reservoir being operative to discharge the second slurry from the reservoir through the orifice; a flow distribution system for introducing the second slurry into the chamber box at spaced-apart feed locations along the chamber box; a flow monitoring system for reading fluid pressure at spaced-apart locations along the chamber box; and a controller arranged to identify which of the feed ports is operatively adjacent a monitored location of highest pressure variation, the controller selectively adjusting output of the flow distribution system at the identified feed location counteractively to the highest pressure variation, the controller adjusting output of a remainder of the feed locations counteractively to the output adjustment at the identified feed location.

FIELD OF INVENTION 
The present invention relates to method and apparatus for applying a 
predetermined pattern of add-on material to a base web, preferably in the 
form of stripes, and more particularly, to a method and apparatus for 
producing cigarettes papers having banded regions of additional material. 
BACKGROUND AND CIRCUMSTANCES OF INVENTION 
Techniques have been developed for printing or coating paper webs with 
patterns of additional material. These prior techniques have included 
printing with gravure presses, blade coating, roller coating, 
silkscreening and stenciling. 
U.S. Pat. No. 4,968,534 to Bogardy describes a stenciling apparatus wherein 
a continuous stencil comes into intimate contact with a paper web during 
application of an ink or the like. The apparatus includes an arrangement 
which draws air through the stencil prior to the application of the ink. 
The mechanical arrangement is such that to change the pattern, the stencil 
must be changed. Additionally, such apparatus are unworkable at the 
wet-end of paper-making machines. 
In the related, commonly assigned application, U.S. Ser. No. 07/847,375, an 
embodiment of a moving orifice applicator is disclosed which includes an 
elongate "cavity block" or chamber and a perforated endless belt whose 
lower traverse passes along the bottom portion of the chamber. The chamber 
is positioned obliquely across a web-forming device (such as a Fourdinier 
wire). In operation, a slurry of additional material is continuously 
supplied to the chamber as the endless belt is looped through the bottom 
portion of the chamber such that plural streams of material are generated 
from beneath the chamber to impinge the web passing beneath the chamber. 
As a result, bands of additional material are applied repetitively to the 
web. The orientation, width, thickness and spacing of the bands are all 
determinable by the relative speed and orientation of the endless belt to 
the moving web. 
Preferably, the pattern of additional material is applied as uniformly as 
possible so as to render consistent product across the entire span of the 
web. However, Fourdrinier machines are very wide (approximately 10 to 20 
feet or more) and that circumstance creates the need to extend the slurry 
chamber to extreme lengths. Accordingly, fluid conditions, particularly 
pressure, at one end of a slurry chamber may differ significantly from 
those at the other. Significantly, we have discovered that variations in 
pressure can cause the fluid discharge from the orifices to vary 
significantly as the orifices move from one end of the chamber to the 
other. 
It is believed that as the belt progresses through the slurry chamber, its 
motion imparts a pumping action upon the slurry. Unless corrective 
measures are undertaken, this action tends to increase fluid pressure at 
the downstream end of the chamber (where the belt exits the chamber). The 
motion of the belt may also create a region of low pressure where the belt 
enters the chamber. Additionally, the very end portions of the chamber 
itself tend to impart flow disturbances. All these circumstances can 
create undesireable variations in the discharge of slurry along the slurry 
chamber and manifest imperfections in the paper product being 
manufactured. 
In U.S. Ser. No. 07/847,375, slurry is introduced into the chamber at a 
plurality of spaced-apart locations along the chamber. However, the slurry 
may be introduced such that it, too, creates local fluid disturbances 
which can be problematic to uniformity. 
When using the applicator in constructing banded cigarette papers, the 
add-on material is usually a form of fibrous cellulose. Such material 
tends to collect at or about edges and corners of the apparatus within the 
chamber. If the collections are allowed to accumulate, they can partially 
or totally clog the perforations of the endless belt and create other 
problems that disrupt proper and efficient operation of the applicator. 
We have also come to realize that unless precautions are undertaken, the 
belt may entrain bits of the slurry and carry them out of the chamber. 
Because the belt moves so quickly, this extraneous slurry is soon thrown 
from the belt, especially where the path of the belt changes direction. 
Such action creates spots and other blemishes on the final product, 
exacerbates machine cleaning requirements and may accelerate wear and tear 
in the applicator. 
OBJECTS OF THE INVENTION 
Accordingly, it is an object of the present invention to provide uniformity 
in the application of a slurry from a moving orifice applicator. 
It is another object of the present invention to provide a capacity to 
correct non-uniformities in fluid conditions along the chamber of a moving 
orifice applicator. 
Yet another object of the present invention is to alleviate the pumping 
action of the moving belt upon fluid contained within the chamber of a 
moving orifice applicator. 
Still another object of the present invention is to eliminate spotting of a 
web as it passes beneath a moving orifice applicator. 
Another object to the present invention is to provide removal of any 
extraneous slurry material that may become entrained upon the endless belt 
of a moving orifice applicator upon exiting the slurry chamber thereof. 
Still another object of the present invention is to provide for the 
introduction of fluid into the chamber of a moving orifice applicator such 
that disruption and non-uniformities in fluid conditions are minimized. 
Yet another object of the present invention is provision for adjustments in 
fluid conditions at spaced locations along the chamber in a manner which 
can dynamically achieve and then maintain a uniform fluid pressure 
throughout the operative portion of the chamber and throughout the 
operation of the applicator. 
Still another object of the present invention is to minimize the disruptive 
effect of end portions of the chamber of a moving orifice applicator upon 
fluid conditions within the chamber. 
SUMMARY OF INVENTION 
These and other objects are achieved with the present invention whose 
aspects include a method and apparatus for the production of a web having 
banded regions of add-on material, more particularly a cigarette paper 
having stripes of additional cellulosic material added thereto. A 
preferred method includes the steps of: establishing a first slurry, and 
preparing a base web by laying the first slurry into a sheet form while 
moving the base web sheet along a first path. The method further comprises 
the steps of preparing a second slurry; and repetitively discharging the 
second slurry so as to establish stripes upon the base web. The last step 
itself includes the steps of establishing a reservoir of the second slurry 
across the first path; moving a belt having an orifice along an endless 
path, which path includes an endless path portion along the reservoir 
where the orifice is communicated with the reservoir so as to discharge 
the second slurry from the reservoir through the orifice onto the laid 
first slurry. The method also includes the step of controlling fluid 
pressure at spaced locations in the reservoir in direction along the 
endless path portion so as to achieve consistent discharge of the second 
slurry. 
Other aspects of the present invention include, among others, the step of 
preparing the second slurry by repetitvely refining a cellulosic pulp 
until a Freeness value is achieved in the range of approximately -300 to 
-900 ml .degree.SR while removing heat from the cellulosic pulp during at 
least a portion of the repetitively refining step; chamber box design 
features which further minimize pressure variations along the reservoir; 
and chamber box features which minimize wear and facilitate maintenance 
and repair.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1A, a preferred embodiment of the present invention 
comprises a cigarette paper making machine 2, which preferably includes a 
head box 4 operatively located at one end of a Fourdrinier wire 6, a 
source of feed stock slurry such as a run tank 8 in communication with the 
head box 4, and a moving orifice applicator 10 in operative communication 
with another source of slurry such as a day tank 12. 
The head box 4 can be one typically utilized in the paper making industry 
for laying down cellulosic pulp upon the Fourdrinier wire 6. In the usual 
context, the head box 4 is communicated to the run tank 8 through a 
plurality of conduits 14. Preferably, the feed stock from the run tank 8 
is a refined cellulosic pulp such as a refined flax or wood pulp as is the 
common practice in the cigarette paper making industry. 
The Fourdrinier wire 6 carries the laid slurry pulp from the head box 4 
along a path in the general direction of arrow 16 in FIG. 1A, whereupon 
water is allowed to drain from the pulp through the wire 6 by the 
influence of gravity and at some locations with the assistance of vacuum 
boxes 18 at various locations along the Fourdrinier wire 6 as is the 
establish practice in the art of cigarette paper making. At some point 
along the Fourdrinier wire 6, sufficient water is removed from the base 
web pulp to establish what is commonly referred to as a dry line 20 where 
the texture of the slurry transforms from one of a glossy, watery 
appearance to a surface appearance more approximating that of the finished 
base web (but in a wetted condition). At and about the dry line 20, the 
moisture content of the pulp material is approximately 85 to 90%, which 
may vary depending upon operating conditions and the like. 
Downstream of the dry line 20, the base web 22 separates from the 
Fourdrinier wire 6 at a couch roll 24. From there, the Fourdrinier wire 6 
continues on the return loop of its endless path. Beyond the couch roll 
24, the base web 22 continues on through the remainder of the paper making 
system which further dries and presses the base web 22 and surface 
conditions it to a desired final moisture content and texture. Such drying 
apparatus are well known in the art of paper making and may include drying 
felts 26 and the like. 
Referring now to both FIGS. 1A and 2, the moving orifice applicator 10 
preferably comprises an elongate chamber box 30 for establishing a 
reservoir of add-on slurry in an oblique relation across the path of the 
Fourdrinier wire 6. The moving orifice applicator also includes an endless 
perforated steel belt 32, whose pathway is directed about a drive wheel 
34, a guide wheel 36 at the apex of the moving orifice applicator 10 and a 
follower wheel 38 at the opposite end of the chamber box 30 from the drive 
wheel 34. The endless belt 32 is directed through a bottom portion of the 
chamber box 30 and subsequently through a cleaning box 42 as it exits the 
chamber box 30, moves toward the drive wheel 34 and continues along the 
remainder of its circumlocution. 
As each perforation or orifice 44 (FIG. 5) of the belt 32 passes through 
the bottom portion of the chamber box 30, the orifice 44 is communicated 
with the reservoir of slurry established in the chamber box 30. At such 
time, a stream 40 of slurry discharges from the orifice 44 as the orifice 
44 traverses the length of the chamber box 30. The discharge stream 40 
impinges upon the base 22 passing beneath the moving orifice 10 so as to 
create a stripe of additional (add-on) material upon the base web 22. The 
operational speed of the belt 32 may be varied from one layout to another, 
but in the preferred embodiment, the belt is driven to approximately 1111 
feet per minute when the Fourdrinier wire is moving at approximately 500 
feet per minute and the chamber box 30 is oriented 27.degree. relative to 
the direction of the wire. The spacing of the orifices 44 along the belt 
32 and the operational speed of the belt 32 is selected such that a 
plurality of streams 40, 40' emanate from beneath the chamber box 30 
during operation of the moving orifice application, simultaneously. 
Because of the oblique orientation of the moving orifice applicator 
relative to the path 16 of the base web 22 and the relative speeds of the 
Fourdrinier wire 6 and the endless belt 32, each stream 40 of add-on 
material will create a stripe of add-on material upon the base web 22. At 
the above speeds and angle, the moving orifice applicator 10 will 
repetitively generate stripes of add-on material that are oriented normal 
to a longitudinal edge of the base web 22. If desired, the angle and/or 
relative speeds may be altered to produce stripes which are angled 
obliquely to the edge of the base web 22. 
For a particular orifice 44, after it exits from the chamber box 30, the 
adjacent portions of the belt 32 about the orifice 44 are cleansed of 
entrained add-on slurry at the cleaning station 42 and the orifice then 
proceeds along the circuit of the endless belt 32 to reenter the chamber 
box 30 to repeat an application of a stripe upon the base web 22. 
Referring particularly to FIG. 1A, the moving orifice applicator is 
preferably situated obliquely across the Fourdrinier wire 6 at a location 
downstream of the dry line 20 where condition of the base web 22 is such 
that it can accept the add-on material without the add-on material 
dispersing itself too thinly throughout the local mass of the base web 
slurry. At that location, the base web 22 retains sufficient moisture 
content (approximately 85 to 90%) such that the add-on slurry is allowed 
to penetrate (or establish hydrogen bonding) to a degree sufficient to 
bond and integrate the add-material to the base web 22. 
Preferably, a vacuum box 19 is located coextensively beneath the chamber 
box 30 of the moving orifice applicator 10 so as to provide local support 
for the Fourdrinier wire 6 and facilitate the bonding/integration of the 
add-on slurry with the base web 20. The vacuum box 19 is constructed in 
accordance with designs commonly utilized in the paper making industry 
(such as those of the vacuum boxes 18) The vacuum box 19 is operated at a 
relatively modest vacuum level, preferably at approximately 60 inches of 
water or less. Optionally, additional vacuum boxes 18' may be located 
downstream of the moving orifice applicator 10 to remove the additional 
quantum of water that the add-on slurry may contribute. It has been found 
that much of the removal of water from the add-on material occurs at the 
couch roll 24 where a vacuum is applied of approximately 22-25 inches 
mercury. 
The moving orifice applicator 10 is supported in its position over the 
Fourdrinier wire 6 preferably by a framework including vertical members 
48, 48' which include a stop so that the moving orifice applicator 10 may 
be lowered consistently to a desired location above the Fourdrinier wire 
6, preferably such that the bottom of the chamber box 30 clears the base 
web 22 on the Fourdrinier wire 6 by approximately one to two inches, 
preferably less than 1.5 inch. 
Preferably, the chamber box 30 is of a length such that the opposite end 
portions 50, 50' of the chamber box 30 extend beyond the edges of the base 
web 22. The over-extension of the chamber box 30 assures that any fluid 
discontinuities existing arising at the end portions of the chamber box 30 
do not affect the discharge streams 40 as the streams 40 deposit add-on 
material across the base web 22. By such arrangement, any errand spray 
emanating from the ends of the chamber box 30 occurs over edge portions of 
the base web 22 that are trimmed away at or about the couch roll 24. 
Either or both of the vertical members 48, 48' of the support frame work 
for the moving orifice applicator 10 may be pivotal about the other so as 
to adjust angulation of the applicator 10 relative to the Fourdrinier wire 
6. However, our preferred practice has been to fix the vertical members 
48, 48' of the support frame work and to vary only the speed of endless 
belt 32 in response to changes in operating conditions of the paper making 
machine 2. 
The chamber box 30 receives add-on slurry from the day tank 12 at spaced 
locations along the chamber box 30. Uniform pressure is maintained along 
the length of the chamber box 30 by the interaction of a flow distribution 
system 60, a pressure monitoring system 62 and a programmable logic 
controller 64 such that the pumping action of the belt 22 and other flow 
disturbances along the length of the chamber box 30 are compensated 
locally and continuously to achieve the desired uniformity of pressure 
throughout the chamber box 30. A main circulation pulp 15 delivers slurry 
from the day tank 12 to the flow distribution system 60. 
Details regarding how the controller initiates and maintains uniform 
pressure along the chamber box 30 will be discussed later in reference to 
FIGS. 9-15. 
Referring now to FIGS. 2 and 3A, the drive wheel 34 is driven by a 
selectable speed motor 52 which is operatively connected to the drive 
wheel 34 by a drive belt. Preferably, the motor 52 is supported by the 
framework of the moving orifice applicator, and both the motor 52 and the 
drive belt are encased within a housing 53 so as to capture any extraneous 
material (such as bits of slurry) that may find its way to and be 
otherwise flung from the drive system of the drive wheel 34. Preferably, 
the motor is an Allen-Bradley Model 1329C-B007NV1850-B3-C2-E2, 7.5 hp., 
with a Dynapa Tach 91 Modular Encoder. Of course, other types and models 
of motors that are known to those of ordinary skill in the pertinent art 
would be suitable for this application. 
The drive wheel 34 is advantageously positioned upstream of the chamber box 
30 along the pathway of the belt 32 so that the belt 32 is pulled through 
the chamber box 30. A significant degree of the directional stability is 
achieved by the close fit of the belt 32 throughout the length of the 
elongate chamber box 30. However, precise control of the tracking of the 
belt 32 about its pathway circuit is effected by placement of an infrared 
proximity sensor 54 at a location adjacent the guide wheel 36. The 
infrared proximity sensor 54 comprises an emitter 56 and a sensor 58 which 
are mutually aligned relative to one of the edges of the belt 32 such that 
if the belt strays laterally from its intended course, a signal from the 
sensor is affected by a relative increase or decrease in the interference 
of the edge with the emitter beam. A controller 59 in communication with 
the sensor 58 interprets the changes in the signal from the sensor 58 to 
adjust the yaw of the guide wheel 36 about a vertical axis so as to return 
the edge of the belt 32 to its proper, predetermined position relative to 
the beam of the emitter 56. 
Suitable devices for the proximity sensor 54 includes a Model SE-11 Sensor 
which is obtainable from the Fife Corporation of Oklahoma City, Okla. 
Referring now also to FIG. 3B, the guide wheel 36 rotates about a 
horizontally disposed axle 36a, which itself is pivotal about a vertical 
axis at a pivotal connection 57 by the controlled actuation of a pneumatic 
actuator 61 The actuator 61 is operatively connected to a free end portion 
36b of the axle 36a and is responsive to signals received from the 
controler 59. Preferably, both the pivotal connection 57 and the actuator 
61 are fixed relative to the general framework of the applicator 10 during 
operation the applicator 10; and a connection 54a is provided between the 
sensor 54 and the free end 36b of the axle 36a so that the sensor 54 
rotates as the yaw of the guide wheel 36 is adjusted. The connection 54a 
assures that the sensor 54 remains proximate to the edge of the belt 32 as 
the guide wheel 36 undergoes adjustments. 
Preferably, the actuator 61 and the pivotal connection 57 are affixed upon 
a plate 39a which is vertical displaceable along fixed vertical guides 39b 
and 39c. Preferably, releaseable, vertical bias is applied to the plate 
39a so as to urge the guide wheel 36 into its operative position and to 
impart tension in the endless belt 32. 
Along the return path of the endless belt 32, from the drive wheel 34 over 
the guide wheel 36 and back to the follower wheel 38, the belt 32 is 
enclosed by a plurality of housings, including outer housings 68, 68' and 
a central housing 70 which also encloses the infrared proximity sensor 54 
and the controller 59 of the tracking system 55. The housing 68, 68' and 
the housing 70 prevent the flash of errand slurry upon the base web 22 as 
the belt 32 traverses the return portion of its circuit. 
Referring particularly to FIG. 2, the housings 70 and various other 
components of the applicator 10 (such as the wheels 34, 36 and 38; the 
chamber box 30; the cleaning box 42; and the motor 52) are supported by 
and/or from a planar frame member 72. The planar frame member 72 itself is 
attached at hold-points 73,73' to a cross-member (an I-beam, box beam or 
the like), which cross-member is supported upon the vertical members 48, 
48'. In the alternative, an I-beam member or a box beam member may be used 
as a substitute for the frame member 72, with the chamber box 30 and other 
devices being supported from the beam member. 
Referring again to FIG. 3A, in either support arrangement, the chamber box 
30 is preferably hung from the support member with two or more, spaced 
apart adjustable mounts 77a, 77b that permit vertical and lateral 
adjustment (along arrows y and x in FIG. 3A, respectively) of each end of 
the chamber box 30 so that the chamber box 30 may be accurately leveled 
and accurately angled relative to the Foundrinier wire, and so that the 
chamber box 30 may be accurately aligned with the belt 32 to minimize 
rubbing. 
Referring now to FIG. 4, the chamber box 30 includes at its bottom portion 
76 a slotted base plate 78 and first and second wear strips 79 and 80, 
which in cooperation with the base plate 78 define a pair of opposing, 
elongate slots 81 and 82 which slidingly receive edge portions of the 
endless belt 32. Preferably, the elongate slots 81 and 82 are formed along 
a central bottom portion of the base plate 78, but alternatively, could be 
formed at least partially or wholly in the wear strips 79 and 80. 
The central slot 84 in the base plate 78 terminates within the confines of 
the chamber box 30 adjacent to the end portions 50, 50' of the chamber box 
30. Preferably, each terminus of the central slot 84 is scalloped so as to 
avoid the accumulation of slurry solids at those locations. The width of 
the central slot 84 is minimized so as to minimize exposure of the fluid 
within the chamber box 30 to the pumping action of the belt 32. In the 
preferred embodiment, the slot is approximately 3/8 inch wide, whereas the 
diameter of the orifices 44 in the endless belt 32 are preferably 
approximately 3/32 inch. 
Each of the wear strips 79, 80 extend along opposite sides of the bottom 
portion 76 of the slurry box 30, co-extensively with the base plate 78. An 
elongate shim 86 and a plurality of spaced apart fasteners 88 (preferably 
bolts) affix the wear strips 79,80 to the adjacent, superposing portion of 
the base plate 78. 
The tolerances between the respective edge portions of the belt 32 and the 
slots 81, 82 are to be minimized so as to promote sealing of the bottom 
portion 76 of the chamber box 30. However, the fit between the belt 32 and 
the slots 81,82 should not be so tight as to foment binding of the endless 
belt 32 in the slots 81, 82. In the preferred embodiment, these 
countervailing considerations are met when the slots 81, 82 are configured 
to present a 1/16 inch total tolerance in a width-wise direction across 
the endless belt 32. In the direction normal to the plane of the belt, the 
belt has preferably a thickness 0.020 inch, whereas the slots 81, 82 are 
0.023 inch deep. These relationships achieve the desired balance of proper 
sealing and the need for facile passage of the belt 32 through the bottom 
portion 76 of the chamber box 30. 
Preferably, the wear strips 79, 80 are constructed from ultra high 
molecular weight polyethylene or Dalron. 
Included within the confines of the chamber box 30 are bevelled inserts 89, 
90 which extend along and fill the corners defined between the base plate 
78 and each of the vertical walls 91, 92 of the chamber box 30. The 
inserts preferably present a 45 degree incline from the vertical walls 91, 
92 toward the central slot 84 of the base plate 78. This arrangement 
avoids stagnation of fluid in the confines of the chamber box 30, which 
would otherwise tend to accumulate the solid content of the slurry and 
possibly clog the chamber box 30 and the orifices 44 of the endless belt 
32. 
Near the bottom portion 76 of the chamber box 30, a plurality of 
spaced-apart pressure ports 94 communicate the pressure monitoring system 
62 with the interior of the slurry box 30. The pressure monitoring system 
62 was previously mentioned with reference to FIG. 1A and will be 
discussed in further detail in reference to FIGS. 9 and 10. 
Along the upper portion of the chamber box 30, a plurality of spaced-apart 
feed ports 96 are located along the vertical wall 91. The feed ports 96 
communicate the flow distribution system 60 with the interior of the 
slurry box 30. Preferably, the feed ports 96 are located close to the lid 
plate 31 of the chamber box 30. The flow distribution system 60 has been 
noted in reference to FIG. 1 and will be discussed further detail in 
reference to FIGS. 9 and 11. 
The feed ports 96 are spaced vertically by a distance h above where the 
endless belt 32 traverses through the bottom portion 76 of the chamber box 
30. The feed ports 96 introduce slurry into the chamber box 30 in a 
substantially horizontal direction. The vertical placement and the 
horizontal orientation of the ports 96 dampened vertical velocities in the 
fluid at or about the region of endless belt 32 at the bottom portion 76 
of the chamber box 30. The arrangement also decouples the discharge flows 
40 through the orifices 44 from the inlet flows at the feed ports 96. 
The height h in the preferred embodiment is approximately 8 inches or more; 
however, the vertical distance h between the feed ports 96 and the endless 
belt 32 may be as little as 6 inches. With greater distances h, there is 
lesser disturbance and interaction between the fluid adjacent the endless 
belt 32 and the fluid conditions at the feed ports 96. 
In the preferred embodiment, the number of feed ports 96 amounted to twelve 
(12), but the invention is workable with as few as 6 inlet feed ports 96. 
Although not preferred, the invention could be practiced possibly with as 
few as 4 inlet feed ports 96. The number of feed ports 96 depends upon the 
width of the paper making machine in any particular application. The 
preferred spacing between the feed ports 96 is approximately 12 inches and 
preferably not greater than approximately 24 inches, although it is 
possible to operate with even greater separation. 
Referring now to FIG. 5, each of the orifices 44 along the endless belt 32 
include a bevelled portion 45 adjacent the side of the endless belt 44 
facing into the chamber box 30. By such arrangement, the solids content of 
the slurry is not allowed to collect at or about the orifices 44 during 
operation of the applicator 10. More particularly, slurry fiber is not 
allowed to collect about the orifice and deflect the jets of slurry being 
discharged. Accordingly, the bevelled portions 45 of the orifices 44 
promote consistent delivery of slurry from the applicator 10 and reduce 
malfunctions and maintenance. 
Referring now to FIG. 6, in an alternate embodiment of the chamber box 30', 
the vertical walls 91', 92', together with the base plate 78' and inclined 
bevelled elements 89', 90' cooperate with a retractable armature 100, 
which at its operative end portion supports an elongate wear strip 102. 
The elongate wear strip 102 extends the length of the chamber box 30' and 
is supported at spaced locations along each side of the chamber 30' by a 
plurality of retractable armatures 100 and 101. In this embodiment, the 
wear strips 79' and 80' are mounted upon and are retractable with the 
armatures 100 and 101, respectively. In FIG. 6, the armatures 100 along 
one side of the chamber box 30 are shown in a retracted position, while 
the armatures 101 along the opposite side of the chamber box 30' are shown 
in an engaged position, where the respective wear strip 90' is biased 
against the base plate 78'. In actual operation, the armatures 100 and 101 
are pivoted between the retracted and engaged positions simultaneously. 
Each retractable armature 100, 101 is pivotally mounted upon one or a pair 
of vertical flanges 106, which preferably provides support for an actuator 
mechanism 107 for moving the retractable armature 100, 101 from an 
operative, engaging position where the wear strips 89', 90' are urged 
against base plate 78' to a retracted position where the wear strips 89', 
90' are spaced away from the base plate 78' and the endless belt 32'. 
The actuator mechanism 107 is preferably an air cylinder 108 which is 
operatively connected to the pivot arms 109, 110 of the armatures 100 and 
101, respectively. Other mechanical expediencies could be selected for 
pivoting the retractable armatures 100 and 101, as would be readily 
apparent to one of ordinary skill in the art upon reading this disclosure. 
An elastomeric seal 104 is provided between the lower portions of the 
chamber box walls 91', 92' and the base plate 78' so as to create a 
fluid-proof seal about the entire periphery of the base plate 78'. 
In operation, all of the armatures 100, 101 along both sides of the chamber 
box 30' are pivoted simultaneously so that the wear strips 79', 80' are 
moved as units to and from their operative and engaged positions. The 
retractable armatures 100, 101 facilitate quick and speedy maintenance, 
repair and/or replacement of the endless belt 32', the wear strips 79', 
80' and the base plate 78'. 
Referring now FIGS. 2, 7 and 8, after progressing through the chamber box 
30, the endless belt 32 enters the cleaning box 42 which is arranged to 
sweep away any entrained slurry that may have been carried from the box 30 
by the belt 32. Preferably, the cleaning box 42 is supported from the 
planar frame member 72 by a bracket 110 and includes an upper and lower 
plate 112 and 114 which are connected to one another so as to be biased 
toward each other by a spring 116 so as to create a moderate positive 
clamping action toward the belt 32. The biasing action of the spring 116 
is adjustable by conventional arrangement such as by a nut 118. The 
biasing spring 116 creates a clamping action of the plates 112, 114 upon 
pairs of fibrous wiper elements 120, each which receive the endless belt 
32 between its upper wiper element 121u and its lower wiper element 121lr. 
In the preferred embodiment, these pairs wiper elements 120 are six in 
number, parallel to one another and arranged at an oblique angle relative 
to the pathway of the endless belt 32. Preferably, each of the upper and 
lower wiper elements 121u and 121lr comprise cotton roping of 
approximately 1/4 to 1/2 each diameter. The endless belt 32 passes between 
the upper and lower wipers 121u, 122lr of each pair of wiper elements 120. 
The pairs of wiper elements 120 sweep slurry material from the endless 
belt 32 as it passes therebetween. Referring particularly to FIG. 8, 
adjacent pairs of wiper elements 120 and 120' defined channels 124' 
therebetween for directing fluid across the endless belt 32 to purge 
extraneous slurry material away from the endless belt 32 as it passes 
through the cleaning box 42. 
In the preferred embodiment, water is introduced through the first 3 
channels 124a-c from nozzles 126a-c to flush the belt 32 with water. 
Thereafter, a plurality of air jet nozzles 128d-f direct airstreams out 
channels 124d-f to sweep extraneous water and any remaining slurry from 
belt 32. Preferably, the drying box 42 is operated such that the belt 32 
is entirely dry before it reaches the drive wheel 34 so that the drive 
wheel 34 does not collect and throw slurry and/or water about the adjacent 
environment. 
Preferably, water is supplied to the water nozzle 126a at approximately 3 
liters per minute (minimum) to the nozzle 126b at approximately 2 liters 
per minute (minimum) and to the nozzle 126c at approximately 1 liter per 
minute (minimum). 
Referring to FIG. 9, as previously described, slurry from the day tank 12 
is delivered to the flow distribution system 60 by a main, circulation 
pump 15. Preferably, exit pressure from the main circulation pump 15 is 
controlled by an appropriate arrangement 140 such as a pressur control 
valve 142 and a flowmeter 144 such that slurry is delivered to the flow 
distribution system 60 at a predetermine pressure, preferably in the range 
of approximately 50 to 70 psig (most preferably approximately 60 psig), 
and in the preferred embodiment, preferably in the range of 4 to 10 
gallons per minute, more preferably approximately 5 gallons per minute. 
Optionally, a supply of chalk that is stored in a chalk tank 146 is 
introduced into the add-on slurry at a location downstream of the 
flowmeter 144, under the control of a chalk metering pump 147 and chalk 
flowmeter 148. Preferably, the arrangement includes a static mixer 149 to 
provide uniform mixing of chalk into the main slurry stream. 
The slurry flow from the day tank 12 and the main circulation pump 15 is 
delivered to the flow distribution system 60, which will now be described 
with reference to the first two of a larger plurality of metering pumps 
150 so that unnecessary duplication of description and designations is 
avoided. 
The flow distribution system 60 preferably comprises a plurality of 
metering pumps 150 (e.g. 150a and 150b), which are each operatively 
controlled by their connections 152 (e.g. 152a and 152b) to the controller 
64, such that signals from the controller 64 can control each pump speed 
(and therefore flow rate) individually and selectively. Each of the 
metering pumps 150a, and 150b are each individually communicated with the 
main circulation pump 15 via a flow circuit 154. The discharge end of each 
of the pumps 150a and 150b are connected (communicated) to one of the feed 
ports 96 (e.g. 96a and 96b), respectively such that preferably each 
metering pump 150 singularly delivers slurry to one of the associated feed 
ports 96. This arrangement is replicated throughout the plurality of 
metering pumps 150 so that each of the individual feed ports 96 along the 
length of the chamber box 30 are connected with one of the metering pumps 
150. The pumps 150a and 150b are communicated to the feed ports 96a and 
94b through lines 156a and 156b, respectively. 
Accordingly, by such arrangement a signal from the controller 64 to the 
first metering pump 150a might establish a pump speed at the metering pump 
150a which delivers a controlled flow rate from the metering pump 150a to 
the first feed port 94a under individual, possibly differentiated rate 
from the flow rates delivered by the other metering pumps 150b-z to the 
other feed ports 94a. 
The control signals from the controller 64 are predicated upon processing 
of signals received from each of the pressure sensors 160 of the flow 
monitoring system 62. For sake of clarity and avoidance of unnecessary 
duplication of description and designations, the flow monitoring system 62 
will be described in reference to the first and second pressure sensors 
160a and 160b. 
Each pressure sensor 160 (e.g. 160a and 160b) is communicated with one of 
the pressure ports 94 through a conduit 162 (e.g. 162a and 162b, 
respectively). Each of the pressure sensors 160 (e.g. 160a and 160b) is 
communicated with the controller 64 through electrical connections 164 
(e.g. 164a and 164b, respectively). 
Such arrangement is repeated for each of the pressure sensors 160 such that 
each of the pressure ports 94a through 94z are communicated with a 
pressure sensor 160 which sends a signal indicative of a local static 
pressure in the chamber box 30 to the controller 64. 
In the preferred embodiment, the number of feed ports 96 numbered twelve 
(12) and the pressure ports 94 numbered twenty-four (24). Accordingly, 
pairs of pressure ports 94 were arranged adjacent each feed port 96 (of 
course, subject to the vertical spacing between the feed ports 96 and the 
pressure ports 94). It is contemplated that the invention is readily 
practiced with even greater numbers of pressure ports 94 and feed ports 96 
or far fewer of the same. In an alternate embodiment, the feed ports 96 
numbered six (6) and the pressure ports 94 numbered twelve (12). The 
invention is operable with even fewer. The total number of feed ports 96 
will depend upon the length of the chamber box 30, with spacing between 
adjacent feed ports 96 being established at less than approximately 24 
inches, and preferably about 12 inches. 
Preferably, the chamber box 30 is operated in a fully filled condition and 
includes a pressure relief valve 166 at the end portion 50' of the chamber 
box 30 adjacent the cleaning box 42. The pressure relief valve 166 is 
provided as a precaution against an undesired build-up of fluid pressure 
within the chamber box 30. 
Preferably, the metering pumps 150 of the flow distribution system are 
mounted apart from the remainder of the moving orifice applicator, such as 
on a separate stand at one end of the moving orifice applicator 10. 
Preferably, the pressure sensors 160 are supported from the planar frame 
member 72 of the moving orifice applicator 10. The metering pumps 150 are 
preferably a progressive cavity type of pump, such as a Model NEMO/NE 
Series from Nezsch Incorporated of Exton, Pa. A host of other equally 
suitable pumps could be used instead. 
Referring now to FIG. 10, each pressure sensor 160 comprises a first 
conduit 162 which communicates a respective sensor port 94 with a chamber 
172. A pressure transducer 174 includes a pressure deflectable membrane 
176 in operative communication with the pressure chamber 172. A second 
line 178 communicates the chamber 172 with a source of water 180. A 
control valve 182 at a location along the conduit 178 is opened and closed 
selectively by a two-way solenoid 184 so as to control the introduction of 
water from the source 180 through the conduit 178, the chamber 172 and the 
conduit 162 for filling those elements with water and for flushing during 
shut-down and maintenance. During operation of the moving orifice 
applicator 10, the control valve 182 remains closed so as to maintain a 
column of water extending from the control valve 182 through the remainder 
of the conduit 178, the chamber 172 and the conduit 162. A check valve 186 
at a location along the conduit 178 between control valve 182 and the 
chamber 172 prevents an undesired backflow of fluid into the control valve 
182 or the water supply 180. 
Referring now to FIG. 11, the preparation of the slurry for the production 
of the cigarette paper using the moving orifice applicator 10 initiates 
with the cooking of flax straw feed stock 190, preferably using the 
standard Kraft process that prevails in the paper making industry. The 
cooking step is followed by a bleaching step 210 and a primary refining 
step 220. Preferably, the preferred process includes a secondary refining 
step 230 before the majority of the refined slurry is directed to the run 
tank 8 of the headbox 4. Preferably, the refining steps 220 and 230 are 
configured to achieve a weighted average fiber length in the flax slurry 
of approximately 0.8 to 1.2 mm, preferably approximately 1 mm. Preferably, 
a chalk tank 240 is communicated with the run tank 8 so as to establish a 
desired chalk level in the slurry supplied to the headbox 4. 
Preferably, a portion of the slurry from the second refining step 230 is 
routed toward to a separate operation 245 for the preparation of an add-on 
slurry for application by the moving orifice applicator 10. This operation 
245 begins with the collection of refined slurry in a recirculation chest 
250 wherefrom it is recirculated about a pathway including a multi-disc 
refining step 260 and a heat exchanging step 270 before returning to the 
circulation chest 250. Preferably, in the course repeating the refining 
step 260 and the heat exchanging step 270, heat is removed from the slurry 
at a rate sufficient to prevent a runaway resculation of temperature in 
the slurry, and more preferably, to maintain the slurry at a temperature 
that is optimal for the refining step 260, in the range of approximately 
135 to 145.degree. F., most preferably approximately 140.degree. F. for a 
flax slurry. The add-on slurry is recirculated along this pathway of steps 
250, 260, 270 and back to 250 until such time that the add-on slurry 
achieves a Freeness value of a predetermined value in the range of 
approximately -300 to -900 milliliter .degree.Schoppler-Riegler (ml 
.degree.SR). The upper end of the range is preferable (near-750 ml 
.degree.SR). 
An explanation of negative freeness values can be found in "Pulp Technology 
and Treatment for Paper", Second Edition, James d' A. Clark, Miller 
Freeman Publications, San Francisco, Cailf. (1985), at page 595. 
Upon completion of the recirculation operation, the extremely refined 
add-on slurry is ready for delivery to the day tank 12 associated with the 
moving orifice applicator 10, wherefrom it is distributed along the length 
of the chamber box 30 of the moving orifice applicator as previously 
described. However, it is usually preferred to undertake a further 
recirculation step 275 wherein the add-on slurry is recirculated from the 
second chest 285 again through the heat exchanger (of step 270) with 
little or no further refining so as to achieve a desired final operational 
temperature in the add-on slurry (preferably, approximately 95.degree. F.) 
prior to delivery to the day tank 12 and the applicator 10. Accordingly, 
the heat exchanger is preferably configured to serve at least dual 
purposes, to maintain an optimal temperatures in the add-on slurry as it 
is recirculated through the refiners and to remove excess heat in the 
add-on slurry at the conclusion of refining steps in anticipation of 
delivery to the applicator 10. 
The second slurry chest 285 also accommodates a semi-continuous production 
of slurry. 
Preferably, the multi-disc refining 260 of the recirculation pathway is 
performed using refiners such as Beloit double multi-disc types or Beloit 
double D refiners. The heat exchangers used in the step 270 of the 
recirculation pathway avoid the build-up of heat in the slurry which might 
otherwise result from the extreme refining executed by the multi-disc 
refiners in step 260. Preferably, the heat exchanger is a counter-flow 
arrangement such as a Model 24B6-156 (Type AEL) from Diversified Heat 
Transfer Inc. For the preferred embodiment, the heat exchanger of step 270 
is configured to have a BTU rating of 1.494 MM BTU per hour. 
Fines levels in the add-on slurry range from approximately 40-70% 
preferably about 60%. Percentiles of fines indicate the proportion of 
fibers of less than 0.1 mm length. 
Preferably, the slurry that is supplied to the head box 4 (the "base sheet 
slurry") is approximately 0.5% by weight solids (more preferably 
approximately 0.65%); whereas the slurry that is supplied to the moving 
orifice applicator 10 (the "add-on slurry") is preferably at approximately 
a 2 to 3% by weight solids consistency. For flax pulp, the Freeness value 
of fibers in the in the base sheet slurry at the head box 4 is preferably 
in the range of approximately 150 to 300 ml .degree.SR, whereas the add-on 
slurry at the chamber box 30 is preferably at a Freeness value in the 
range of approximately -300 to -900 ml .degree.SR, more preferably at 
approximately -750. Preferably, the solids fraction of the base sheet 
slurry is approximately 50% chalk and 50% fiber, whereas in the add-on 
slurry, the relationship is approximately 10% chalk (optionally) and 90% 
or more fiber. Optionally, the add-on slurry may include a 5 to 20% chalk 
content, preferably a Multiflex that is obtainable from Speciality 
Minerals, Inc. 
As previously described in reference to FIG. 1A, the add-on slurry is 
applied to the base web by the applicator 10, whereupon water is further 
removed and the sheet is dried upon passage through the drying felts 26. 
Referring now also to FIG. 1B, at the conclusion of the paper making 
process, a paper is constructed having a base sheet portion 3 and a 
plurality of uniformly applied, uniformly spaced, mutual parallel banded 
regions 5 of highly refined add-on cellulosic material of weighted average 
fiber length in the range of approximately 0.15 mm to 0.20 mm. In these 
banded regions 5, the cigarette paper has a reduced air permeability in 
comparison to that of the regions of the base sheet 3 between the banded 
regions 5. Referring now also to FIG. 1C, the paper is wrapped about a 
column of tobacco to form the tobacco rod of a cigarette 7, which will at 
the banded regions exhibit a slower burn rate in comparison to those 
regions of the base sheet 3 between the banded regions 5. 
The operation of the cigarette paper making machine and method of the 
preferred embodiment has been described with respect to flax feedstock. 
The apparatus and associated methodologies are readily workable with other 
feedstocks such as hardwood and softwood pulps, eucalyptus pulps and other 
types of pulps used in the paper making industry. The alternate pulps may 
have different characteristics from flax, such as differences in averge 
fiber length, which may necessitate adjustment of the degree of refining 
in steps 220 and 230 in the preparation of the base sheet slurry with some 
pulps. With an alternative pulp, it may be acceptable to skip one or both 
of the refining steps 220 and 230, particularly if the pulp exhibits a 
very short average fiber length in comparison to flax. However, in order 
for the preparation of the add-on slurry to progress satisfactorily, the 
slurry which is to be diverted to the recirculation chest 250 should 
exhibit an initial weighted average fiber length approximating that 
previously described for the refined flax base sheet slurry, that is, 
having a weighted fiber length of approximately 0.7 mm to 1.5 mm and more 
preferably aproximately 0.8 mm to 1.2 mm. With these alternative pulps, 
the add-on slurry is recirculated through the refining step 260 and the 
heat exchanging step 270 until a comparable desired Freeness value is 
obtained (in the range of -300 to -900 ml .degree.SR, preferably 
approximately -750 ml .degree.SR). As with flax, the extreme degree of 
refining of the add-on slurry avoids fiber build-up at or about the 
orifices 44 or the belt, which in turn avoids jet deflections at the 
orifices 44. 
Because the flow of the fluid stream 40 emanating from each orifice 44 as 
the orifice 44 passes along the bottom portion of the chamber box 30 is 
proportional to the pressure differential across the orifice 44, it is 
imperative that fluid pressure be established and then held as uniformly 
as possible along the entire journey of each orifice 44 along the bottom 
portion 76 of the chamber box 30. The discussion which follows with 
reference to FIGS. 12A-C provide the preferred control logic operation for 
execution by the controller 64 in operating the flow distribution system 
60 responsively to the pressure monitoring system 62 such that uniformity 
is achieved in the discharge streams 40 from each orifice 44 as they 
journey along the bottom portion 76 of the chamber box 30. 
Fundamentally, the controller 64 preferably executes a fuzzy logic control 
operative which is predicated upon the following rules: 
1. total slurry flow into the chamber box 30 will be maintained at a 
predetermined, grand total flow rate; 
2. all metering pumps will be operated initially at the same speed/flow 
rate to deliver the desired total flow rate; 
3. because the metering pumps 150 will operatively confound each other, 
adjustments in pressure will be undertaken locally with only a small 
subset of the total number of pumps, such as one or two metering pumps 150 
at a time (or optionally from one to five or more, depending on the size 
of the chamber and/or the number of metering pumps); 
4. no adjustment will be undertaken if the variance in pressure readings 
along the chamber box 30 falls within a predetermined, acceptable level 
(or threshold); 
5. a local adjustment in pressure (by adjusting the pump speed of a 
selected metering pump 150) will be undertaken only upon a demonstration 
that the causal local condition (a low or high pressure perturbation 
beyond the predetermined threshold) has persisted for a predetermined 
amount of time; 
6. that the degree of adjustment will be scaled relative to the magnitude 
of the perturbation such that detection of a small scaled, persistent 
perturbation will necessitate a small adjustment and detection of a large 
scaled, persistent perturbation will necessitate a large adjustment; and 
7. even after an adjustment, further adjustments will not occur until after 
the condition persists for predetermined amount of time as set forth in 
step 5. 
Referring now to FIG. 12A, the controller 64 preferably executes steps 
which initiate with setting the total flow rate (step 210), which in the 
preferred embodiment may be in the range of 5 or 6 gallons slurry per 
minute for a typically sized paper making machine. Larger machines may 
require larger flow rates. Additionally, in a step 220 a target range of 
pressure ("P.sub.range ") is established, which in the preferred 
embodiment identifies a total range of variation in pressure along the 
chamber box 30 that is acceptable for proper and consistent operation of 
the moving orifice applicator 10. As way of non-limiting example, the 
pressure range of variation may be selected to the 1.5 inches of water or 
less when the operational pressure at the bottom portion 76 of the chamber 
box 30 is established at or about 6 to 18 inches water (more preferably, 
approximately 6 to 8 inches of water). 
Once the total flow rate and P.sub.range have been established, the 
controller 64 executes a first subroutine 205 to resolve whether flow 
conditions in the chamber box 30 warrant an adjustment in the flow rate of 
any of the metering pumps 150. The subroutine 205 begins with the pressure 
monitoring system 62 being tapped in a step 230 to read each of the 
plurality of pressures along the pressure ports 94. In the preferred 
embodiment, 24 pressure readings would be undertaken in step 230. All 
these pressure values ("P.sub.i ") are used to calculate an average 
pressure ("P.sub.ave ") in a step 240. Also the controller 64 resolves 
which amongst all the values of pressure (P.sub.i) is the highest pressure 
reading ("P.sub.max ") and which is the lowest pressure reading 
("P.sub.min "). In a step 260, the controller 64 resolves a value for the 
actual pressure range from the difference between P.sub.max and P.sub.min. 
A test ("Test No. 1") is then conducted in a step 270 which compares the 
actual pressure range to the target pressure range that had been 
predetermined in step 220. If the actual pressure range is less than the 
target pressure range, the fluid conditions in the chamber box 30 are 
nominal and the controller 64 sets itself to execute a timing step 275 
which creates a 10 second delay before looping back to the pressure 
reading step 230 to repeat this sub-routine to again check the 
acceptability of variance in the new set of pressure readings P.sub.i 
throughout the length of the chamber box 32. 
If the actual pressure range is greater than the target pressure range, 
then the logic circuit proceeds to the next test 280 ("Test No. 2") which 
determines whether this (positive) result of the first test has persisted 
for a predetermined time, such as being repeated consecutively for one 
minute (i.e., 6 consecutive occurrences in view of the 10 second delay 
created in step 275 between each pressure reading step 230). If this Test 
No. 2 has not been met, then the logic circuit sets itself to execute the 
timing step 275 before looping back to the pressure reading step 230. If 
the Test No. 2 has been positive for a pre-determined number of 
consecutive times, then the logic circuit enters a flow control subroutine 
290. 
Referring now to FIGS. 12B and 12C, the flow control subroutine 290 
preferably includes a first logic regime A which undertakes to resolve 
which one of the metering pumps 150 is to have its speed (and therefore 
its flow rate) adjusted to overcome the non-uniformities in pressure 
readings along the chamber box 30. The logic regime A adjusts the speed of 
whichever pump 150 will contribute the greatest impact on the pressure 
profile along the chamber box 30. A second logic regime B resolves whether 
conditions are such that a greater magnitude in adjustment in pump flow 
must be undertaken or whether a lesser adjustment is to be executed. A 
final logic regime C resolves how all of the remaining metering pumps 150 
are to be adjusted (preferably equally) so that the total flow rate 
delivered by the flow distribution system 60 into the chamber box 30 is 
maintained at the predetermined value established in step 210. Upon 
execution of logic regimes A through C, the controller returns back to the 
timing step 275 for the ten second delay and then to the pressure reading 
step 230 to reinitiate pressure readings. 
The logic regime A includes the steps of resolving at each pressure port 94 
a pressure differential (".DELTA.P.sub.i ") between the respective 
pressure reading Pi and the average pressure calculated in step 240. 
Absolute values of these pressure differentials .DELTA.P.sub.i are then 
resolved in a step 310 and compared such that a resolution of the greatest 
absolute value among all values of pressure differentials .DELTA.P.sub.i 
is ascertained. The controller 64 then executes steps 330 and 340 to 
identify which metering pump 150 is operatively adjacent the pressure port 
94 which provided the greatest absolute value amongst all the values of 
pressure differentials .DELTA.P.sub.i 
Once that metering pump has been identified, the controller 64 enters the 
logic regime B so as to resolve the appropriate magnitude of adjustment in 
accordance with a flow adjustment subroutine 350. 
Preferably, the flow adjustment subroutine 350 includes a test ("Test No. 
3") in a step 360 wherein it compares the pressure differential 
.DELTA.P.sub.i of the identified metering pump to a threshold value (such 
as 3 inches of water). If the measured pressure differential 
.DELTA.P.sub.i is greater than the threshold value, the logic circuit 
generates a control signal to the selected metering pump 150 to adjust its 
pump flow rate by a greater factor, which in the preferred embodiment is 
predetermined to be 10 percent of its then existing flow rate. In 
addition, if the measured pressure differential is negative (the local 
pressure is below the average pressure, then the pump flow of the selected 
metering pump 150 is increased by 10 percent. If the measured pressure 
differential is positive then the pump flow is reduced by 10 percent. 
If the Test No. 3 at step 360 indicates that the absolute value of measured 
pressure differential is less than the threshold value (3 inches of 
water), then the logic circuit executes a signal generating step that 
commands an adjustment of flow rate in the identified pump by a lesser 
factor, which in the preferred embodiment is a five percent adjustment in 
flow rate (or speed). Upon executing either step 370 or 380 as a result of 
Test No. 3 and step 360, the logic circuit then executes the third logic 
subroutine C. 
The logic regime C is arranged to maintain the grand total flow rate into 
the chamber box 30. It initiates with an analytical resolution of the 
change in total flow rate (".DELTA. Flow Rate") resulting from the 
adjustment in the pump flow of the selected metering pump 150 from the 
execution of the logic regime B. It then executes a step 400 in 
communication with all the remaining, non-selected metering pumps 150 to 
adjust each of the remaining (non-selected) metering pumps 150, preferably 
equally, in compensation of the .DELTA. Flow Rate contributed by the 
selected metering pump so as to maintain the predetermined, grand total 
flow rate that had been established in step 210. 
For example, if the first metering pump 150a is selected in logic regime B 
to have its flow rate increased by 10 percent in step 370 thereof, then in 
step 400 of logic regime C, all other metering pumps (150b through 150z) 
would have their flow rates decreased equally by the change in flow rate 
at pump 150a divided by the number of pumps in the set defined by pumps 
150b through 150z. 
Upon completion of the logic regime C, the logic circuit returns to the 
timing step 275, and after the 10 second delay, to the pressure reading 
step 230. 
Referring now to FIGS. 13 and 14, an applicator 10 having 24 pressure ports 
was started with a total slurry flow rate target of 6 gallons per minute, 
with all of the metering pumps 150 set at essentially equal speds, and 
with the controller 64 being inoperative. As shown in FIG. 13, under such 
conditions, the pressure along the chamber box was lowest at the inlet end 
(where the belt enters the chamber) and continued to generally increase 
along the chamber box 30 to the opposite end of the chamber box 30, 
creating a spread of pressure variation of approximately 8.3 inches of 
water. 
Contrastingly, upon activation of the controller 64 and further operation 
of the slurry applicator, the pressure readings along the chamber box 
progressed toward those shown in FIG. 14, wherein the spread of pressure 
variation is reduced to 1.6 inches water. Having discovered that flow-rate 
at the orifices is very sensitive to discontinuities in chamber box 
pressure, the improved pressure uniformity achieved with the present 
invention contributes a more uniform discharge through each belt orifice 
as it moves along the bottom portion of the chamber box 30. 
Referring now to FIG. 15, a graphical representation is provided typifying 
fluid conditions in relation to a progression of time in an operation of 
the applicator 10 in accordance with the teachings of the present 
invention, wherein a line x indicates average pressure in the chamber box 
30, line y indicates flow rate through the the chamber box 30 and line z 
indicates the magnitude of pressure variation along the chamber box 30. 
Line z evidences how in this example pressure variation is reduced to 
approximately one-third of initial values in a short period of time. 
In operation, the desired uniform pressure level within the chamber box 30 
as configured in the preferred embodiment is preferably between 6 to 18 
inches of water. In some applications, it may be necessary to operate at 
higher pressures. 
Many modifications, substitutions and improvements may be apparent to the 
skilled artisan without departing from the spirit and scope of the present 
invention as described and defined herein and in the following claims. By 
non-limiting examples, other expedients for maintaining uniform pressure 
in the chamber box and consequently, uniform jetting of slurry would 
become apparent to one of ordinary skill in the art upon reading this 
disclosure. Such alternatives might include establishing the desired, 
differentiated flow rates of the metering pumps empirically or through 
alternative feedback and looped control routines. In the preparation of 
the add-on slurry, different consistencies and feedstocks might be used, 
or different types or refiners and heat exhangers. Likewise, the base 
sheet slurry need not be nessarily laid upon a Fourdinier wire, but 
instead, could be placed upon an endless steel belt or any other 
arrangement known in the pertinent art as suitable for establishing a base 
web. Additionally, the base plate 78' might be rendered retractable in a 
like manner as were the shims 79' and 80' in the embodiment shown in 
FIG.6.