Controlled operation chocolate refiner

A refiner for mixtures and suspensions having a non-Newtonian rheological characteristic, such as chocolate, which comprises a plurality of power driven refining rollers, and a means of changing the pressure thereof on the respective supports, wherein a means is also provided which is effective to change the actual crowning of the rollers, or the effect of an equivalent crowning, as well as a means of changing the speed of said refining rollers. The crown change is achieved by having the individual rollers supported on an oscillating support adapted to oscillate its respective roller relatively to the associated roller by rotation about an orthogonal midaxis with respect to the roller longitudinal axes, thereby a contact point is established at the roller middle area or circumference while their ends are offset. The speed of the refining rollers is changed through independent and individually operated controls, such as a DC motor. By changing the pressure, crowning, and speed of the rollers, either individually or in combination, the machine may find universal applicability to different viscosity products in desired conditions.

BACKGROUND OF THE INVENTION 
This invention relates to chocolate refiner having universal operation 
characteristics. 
As is known in the art, chocolate refiners functions to impart chocolate 
with a determined fineness or grain size, while making it as homogeneous 
as possible. The fineness degree aimed at is dictated by the subsequent 
utilization of the chocolate. For chocolate products of fine quality, 
degrees of fineness in the order of about 15-30 .mu.m are usual. That 
fineness is achieved by successively squeezing the chocolate through a 
plurality of refining roller pairs which are spring loaded in succession 
against each other, the inlet pair forming the feed-in roller pair and the 
last of the rollers forming the delivery roller. 
With such prior machines, one can adjust the pressure on the individual 
rollers either separately or simultaneously on all rollers. The latter are 
set apart from each other to form a nip through which the material 
entrained therealong by adhesion is caused to pass. The speeds of the 
individual rollers increase from the inlet roller pair to the delivery 
roller. Conversely, the thickness or depth of the chocolate film will 
decrease from the inlet roller pair (e.g. at about 100-400 .mu.m) toward 
the delivery roller (e.g. to 15-30 .mu.m). The refining action results 
from a simultaneous compression or squeezing action, and a drawing or 
shearing action exerted on the chocolate film. The refining rollers are 
currently quite wide. e.g. up to about two meters wide. Accordingly, it is 
specially difficult to maintain such small thicknesses over such great 
widths with those rollers. 
It is known to control the thickness of the chocolate film being delivered 
by varying the pressure of the refining rollers, in particular of the 
feed-in roller pair. 
Owing to high pressure levels being used between the rollers during the 
refining process, the roller surfaces tend to flex inwardly, along the 
opposed generatrices thereof, resulting in the formation of an increased 
depth slit at the middle. This phenomenon is made quite appreciable by the 
refining rollers being of hollow construction, i.e. constructed to convey 
a cooling medium through their interiors, that is a medium effective to 
remove the heat generated during the refining process. To oppose that 
hogging tendency, it is known to construct the refining rollers with a 
degree of compensating counter-crown. The latter will, of course, be taken 
up in operation by a set working pressure in the presence of a product 
having a given viscosity. Refiners have, therefore, been constructed 
heretofore for given thicknesses of the chocolate films to be delivered. 
As the viscosity of the product to be processed varies, e.g. between 
batches, an attempt is made at maintaining the desired fineness by 
changing the roller pressure, the rollers being carried in slidable 
supports mounted in the machine frame. 
In actual practice, it has been found that in spite of the control exerted 
on the refining roller support pressure, it is very difficult to achieve 
and maintain the desired degrees of fineness as the viscosity of the 
product to be processed changes, particularly where high production 
outputs are aimed at. Of course, for each individual refiner, the amount 
of crowning for each roller is determined in accordance with the 
experience gained by the manufacturer in relation to the characteristics 
of a product to be refined. 
Thus, with one prior refiner, it is impossible to provide a product film 
having a fineness which deviate appreciably from the machine fineness 
rating. With products whose viscosities are markedly different, the user 
has been obliged heretofore to purchase a range of refiners. As an 
example, in the United States, highly liquid pastes are often used, 
whereas in Germany and Greece quite different pastes are often adopted. 
While this does not represent a major difficulty for large chocolate 
producers, the cited limitation to prior refiners may be economically 
unacceptable for small producers, who have been forced to modify the 
formulations and technological cycles of their products to meet the 
requirements of prior refiners and make the products processable on such 
machines. This reflects sometimes unfavorably on the characteristics of 
the finished product, because a change in the fat content of the chocolate 
paste, as made necessary in order to make it processable, would later 
affect the refining operation, which is known to impart the final product 
with its specific taste. 
Alternatively, where the preset crowning fails to provide a product having 
a desired fineness, or where the product viscosity changes, it has been 
common practice heretofore to mechanically manipulate the machine itself. 
That manipulation may affect the amount of crown and roller speeds. In the 
former case, the rollers must be disassembled and returned to the machine 
manufacturer, thereafter they are delivered back to the user for 
reassembling, which operation usually takes some weeks. In the latter 
case, since speed changes would generally be small, the roller gears have 
to be altered or replaced. Both operations are of an empirical nature and 
carried out by trial and error, depending on one's experience, thereby 
they may be easily unsuccessful, and in all cases quite expensive, 
time-consuming, and the cause for considerable downtime. 
SUMMARY OF THE INVENTION 
It is a primary object of this invention to provide a chocolate refiner 
which can accommodate chocolate films of different thicknesses for 
processing, as well as significantly different initial viscosities 
thereof, thereby the refiner may be utilized as a universal type of 
refiner. 
A further object of the invention is to provide such a refiner which can 
operate in a fully automated mode, that is capable of producing in a 
self-adjusted manner and on a continuous basis chocolate films having a 
desired thickness from different types or formulations of the starting 
chocolate paste, or in the presence of deviations thereof, thereby 
virtually any types of chocolate may be refined on the same machine, and 
by converse, for a given chocolate type, the machine may be adjusted to 
suit desired product and operation parameters. 
These objects are achieved, according to this invention, by a refiner for 
mixtures and suspensions having a non-Newtonian rheological 
characteristic, such as chocolate, inks, paints, and the like, comprising, 
carried in a frame, a pair of rollers for feeding in a chocolate paste to 
be refined, and a plurality of refining rollers and actuators therefor, as 
well as a means effective to cause a pressure change on the supports for 
the refining rollers, characterized in that it comprises, in combination: 
(a) a means effective to produce a change in the actual crowning, or in the 
effect of an equivalent crowning, of the refining rollers; 
(b) a means effective to produce a speed change in said refining rollers; 
and 
(c) a means effective to produce a change in the pressure on the refining 
rollers; 
a control means being associated therewith for effecting either 
individually or in combination required adjustment actions on said means 
to change the pressure on the refining rollers, and change the speed and 
crowning thereof, a microprocessor control unit means, and gauges for 
measuring a pilot reference parameter for the microprocessor, such as the 
thickness of the product film being delivered or the viscosity thereof, 
being also preferably provided. 
Further embodiments of this invention are characterized by the features 
particularly pointed out herinbelow. 
To achieve its objects, the invention utilizes the principle of acting on 
the pressure existing between refining rollers and simultaneously, or 
alternatively, also on the other two parameters which, as found in the 
course of actual tests, can affect the final fineness value, namely on the 
roller crowning and speed thereof. 
By manipulating the indicated parameters, it becomes advantageously 
possible to achieve at any one time a desired fineness in high output rate 
conditions. 
The roller speeds are changed according to the invention by providing each 
roller to advantage with an independent control which is adjustable as 
desired and comprises, for examples, a mechanical motor speed variator or 
a DC electric motor. It would be readily possible to use expanding pulleys 
or other devices known per se. It should be noted that by changing the 
speed of the first roller in the feed-in roller pair, one can influende 
both the final fineness degree and hourly production rate. It is further 
pointed out that an increase of the relative speed differential between 
any two adjoining rollers results in a higher degree of refining. 
According to the invention, the variations in the roller crownings are 
accomplished indirectly by slanting the axes of two contiguous rollers 
with respect to each other with a pivotal motion centered on the middle of 
such rollers, thereby contact is maintained between the two rollers at the 
middle region thereof, while the gap therebetween increases gradually 
toward the ends. This is the equivalent, in practice, of increasing the 
amount of crown therein. This solution affords the important advantage of 
making the rollers shiftable in a relatively simple, quick, and reliable 
manner using conventional means. 
In a further embodiment of this invention, a crowning change is produced by 
changing the pressure level of the liquid coolant contained within the 
rollers, thereby the crowning change is substantially proportional to the 
variation in the applied pressure. 
Said pressure may be varied advantageously with the intermediary of devices 
and circuitry known per se. 
Advantageously, according to the invention, any variations of the 
adjustment parameters, and specifically of the roller pressure, crowning, 
and speeds, are determined or established automatically through an 
intervening microprocessor. The latter would process input signals 
representative of a reference parameter, e.g. thickness or fineness of the 
chocolate film being delivered, or of the viscosity of the chocolate batch 
to be treated, and supply output signals causing an adjustment action 
being brought about on one or more of the adjustment parameters. The 
thickness of the film being delivered may be measured indirectly and 
advantageously by means of a colorimeter, as disclosed in Italian 
Application No. 20 718 A/83 by this same applicant. Since the effects of 
adjusting a single adjustment parameter, such as the roller pressures, 
crownings, or speeds, also reflects on the remaining two parameters 
influensing them, the selection of the parameter(s) of adjustment to be 
acted upon will be made either manually, in the instance of manual 
adjustment facilities, in accordance with operation curves of the refiner, 
or directly by the microprocessor in accordance with stored reference 
values or specific routines.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Making reference to the drawing views, where similar parts are identified 
with like reference characters, FIGS. 1 and 2 show two contiguous refining 
rollers having a profile shaped lateral surface, i.e. a crowned one as 
shown in an exaggerated way for clarity of illustration. Such profiles 
follow essentially a symmetrical parabola pattern. In the example shown, 
the two rollers 1 and 2 have coplanar longitudinal axes, thereby the same, 
when viewed from above, overlap each other. The parabola profiles are are 
arranged to touch each other at the midpoint 0 and move gradually away 
toward the ends. This condition corresponds to a zero load or pressure 
condition of the refining roller supports. In operation, the pressure on 
the roller supports will cause a deflection in the crowned profile at the 
respective opposed generatrices, thereby the creation of the most uniform 
gap or product thickness possible is approximated over the entire length 
of the rollers. Actually, and as mentioned hereinabove, with a fixed 
profile design this may only be achieved within a very small thickness 
range and in the presence of uniform product viscosity and operating 
parameters, such as speed, output rate, etc. 
According to the invention, in order to provide at any one time the 
required amount of crowning to meet individual requirements, the use of 
devices is herein proposed which are effective to determine a variation in 
the real crowning effect, that is in the actual crowning measurable on the 
rollers, or equivalent crowning. In the former case, the invention 
provides for the use of pressure amplifiers, indicated at 3 in FIG. 1, 
acting on the pressure of the liquid coolant inside the rollers. By 
raising the pressure of the liquid coolant, the amount of crowning is 
increased, and viceversa. According to the invention, a means of 
controlling the temperature of the liquid coolant is also provided in 
order to be able to also control the roller temperature in a desired way. 
An equivalent crowning variation may be obtained, advantageously according 
to the invention, by the provision of an oscillating support for the 
refining rollers, as shown in FIGS. 2 to 6. In this embodiment, the 
rollers may be made truly cylindrical because the crowning effect would be 
achieved by the expedient of causing said rollers to oscillate with 
respect to each other, acting either on each roller or both rollers. In 
the example shown, the rollers overlap and may be swung in a vertical 
plane about the vertical midaxis of said rollers, indicated at 0'. Each 
variation in the roller angle of oscillation results in a change of the 
distance separating the centers of the end circumferences, which occurs 
proportionally also with the various circumferences included between the 
end and middle ones, which are at all times in contact irrespective of the 
angle of oscillation selected. 
Thus, such rollers form "variable crowning" rollers. 
The swinging support device for the refining rollers, according to the 
invention, will be now described with reference to FIGS. 3-6. The rollers 
of the refiner are indicated at 4, 5, 6, 7, and 8, respectively. The 
rollers 4 and 5 form the first and second rollers in the pair of feed-in 
rollers, and the roller 8 forms the delivery roller. 
In the example shown, the rollers 6, 7, and 8 are carried individually in a 
support 9, 10, 11 at one end, and in a support 12, 13, 14 at the other 
end. Such supports have been selected with the same configuration for the 
rollers 6, 7, 8, as shown particularly in FIG. 4. They accommodate 
bearings 15, 16 carrying the end spindles 17, 18 of the rollers. The 
supports 9, 10, 11 and 12, 13, 14 are connected together by a shaft 19 
which is carried, through bearings 20, 21, on the uprights 22, 23 of the 
frame, no further illustrated, of the refiner. As may be seen particularly 
in FIGS. 3 and 4, the shaft 19 has at its ends respective cams or 
eccentric spindles 24, 25 juxtaposed with respect to each other. The cams 
24 and 25 are accommodated in two bushings 26, 27, respectively on the 
supports 9, 10, 11 and 12, 13, 14. A 90 degrees rotation of the shaft 19 
causes a like rotation of the cam 24, which moves the support 9 in the 
direction of the arrow F, while the cam 25 moves the support 12 in the 
opposite direction as indicated by the arrow F1. There results an 
oscillation of the longitudinal axis of the roller 6 through an angle 
.alpha. in the horizontal plane. 
At the ends, the axis of the shaft 19 and associated roller will be shifted 
from its preceding position at one end by an amount "d" equal to the 
amplitude of the oscillation by the cam 24, and at the other end, by a 
similar amount "d" equal to the amplitude of the cam 25, since both cams 
24 and 25 have similar dimensions. 
The 90-degree movement of the cams about the axis of the shaft 19 is 
accomplished by means of a lever 28. The latter is driven by a nut screw 
29 engaging with the worm 30 which is driven rotatively by a DC motor 31. 
The latter may be controlled either independently or, as explained 
hereinafter, by means of a control microprocessor 32. Indicated at 33 is 
an interface or converter of digital-analog signals. 
The engagement of said lever 28 with the nut screw 29 is accomplished, as 
shown in FIGS. 3 and 4, by means of a throughgoing end seat 34 of 
slit-like configuration in the forked end of the lever 28, wherewith two 
opposed pins 35 of the nut screw 29 engage. 
Shown in detail in FIG. 5a are two adjacent rollers such as 6 and 7, the 
longitudinal axes whereof lay in a common vertical plane and the 
respective cams 24 whereof are in their upper positions. Following 
rotation of the same, or of their shaft 19, through 90.degree., said cams 
will bring about a displacement of associated supports 9, 12 and 10, 13, 
or of the related pivots of the rollers 6 and 7, by an amount "d" equal to 
the cam amplitude of oscillation, as may be seen in FIG. 5b. In the 
example shown, accordingly, the rollers 6 and 7 will be offset at their 
ends by an amount 2d. 
While in the example shown the rollers 6, 7, and 8 are supported swingingly 
by means of the supporting devices illustrated, in the instance of the 
roller 5 in the pair of feed-in rollers 4 and 5, this has end supports 36 
made rigid with the refiner frame (FIG. 6). The roller 4 is supported, in 
the example considered, to be displaceable by an oscillating supporting 
device configured, by way of example, in accordance with a modification 
with respect to the device illustrated for the rollers 6, 7, and 8. The 
oscillating support for the roller 4 is shown best in FIGS. 6 and 6a. That 
support comprises two lateral sides 37 which support, at the middle region 
thereof, the pivot pins or spindles of the roller 4 and cooperate at their 
upper ends 37a with a reaction abutment 39 of an oil-operated device 40 
rigid with the machine frame and controllable through a pressure amplifier 
41 associated with a pneumatic servocontrol 42. The same, in the instance 
of a central control unit, is connected to a drive motor 43 piloted by the 
microprocessor 32. The lateral sides 37 have holes 44 formed at their 
opposed ends 37b which accommodate a spindle, or journalled end 45 of the 
shaft, in turn housed in a corresponding seat of a respective oscillating 
lateral side 46. Said lateral sides 46 are hinged at 47 to a respective 
end support 48 rigid with the refiner frame. The oscillating lateral sides 
46 have an oblique lower side 49 in the form of an abutment incline 
wherewith cooperates a respective actuating incline 50, set slidable over 
a respective bearing surface 51 rigid with the machine frame. Each incline 
50 is made rigid at one end with a nut screw 52 which is threaded onto a 
worm 53 adapted to be rotated by a reversible electric motor 54. The same, 
in the central control unit embodiment, is connected to the microprocessor 
32. Rotation of the worm 53 in either directions causes the incline 50 to 
be moved forward or rearward, with attendant raising or lowering of the 
oscillating lateral sides 46 and consequently of the lateral sides 37, and 
hence of the cylinder 4. In order to make the movements smoother, 
intervening rolling bodies may be introduced, e.g. in the form of balls or 
rollers, between the sliding surfaces. Shown in FIG. 6b is the oscillatory 
movement of the roller 4 relatively to the next roller 5. 
FIG. 6 depicts the whole assembly formed by the oscillatory supporting 
device for the refining rollers and the air-oil circuit and the powered 
pressure regulators for controlling and adjusting the pressure of the 
refining rollers 6, 7, and 8. In FIG. 6, there are indicated at 55 and 56, 
respectively, a colorimeter and viscosimeter. The same function to provide 
a reference quantity indicative, respectively, of the thickness of the 
chocolate film beng delivered and of the viscosity of the chocolate batch 
being fed in, in order to provide a reference parameter for the central 
control unit of the refiner. The colorimeter and viscosimeter may be any 
ones. A suitable colorimeter is disclosed in Italian Patent Application 
No. 20 718 A/83, filed on Apr. 21, 1983 by this same applicant. The 
colorimeter serves the purpose of supplying a control unit, advantageously 
a microprocessor, with processed values of the delivered film color, as 
sensed and indirectly representative of the thickness thereof. With these 
devices the real thickness of the film being delivered is monitored over 
its entire width, or the possible appearance of so-called "dry bands" is 
monitored. In the refiner according to the cited application, the 
processed optical readout signals are utilized to control the pressure to 
the supports of the refining rollers. According to this application, the 
same function to pilot the microprocessor 32. That same piloting action 
could be provided by signals supplied from the viscosimeter 56 located 
directly upstream of the feed-in roller pair, 4 and 5. In the instance of 
the colorimeter, sensing of a darker color hue means a larger thickness 
than a paler hue sensing. Thus, if in operation a darker zone is sensed at 
the middle region of the chocolate film being delivered, then this may 
either mean that an insufficient pressure is applied to the refining 
rollers or that the crownning amount is too low, or both. To restore the 
desired conditions, a pressure increase will be then brought about through 
the regulators 57, 58 (FIG. 6), and if that action proves inadequate, then 
the crowning effect value is increased by acting on the oscillatory 
supporting devices through their actuators 54 and 31 until the color hue 
on the film being delivered shows to be once again uniform over the entire 
width thereof. 
It should be enhanced that in treating highly viscous products, i.e. on the 
occurrence of a viscosity increase in the body or batch of chocolate to be 
treated, one is first of all to increase the pressure on the first roller 
4. Should that action be inadequate to provide the required fineness, one 
would then act on the speed of said roller 4 by reducing it, and 
optionally and proportionally, by reducing also that of the following 
refining rollers. 
Upon the occurrence of a chocolate film which is delivered with a greater 
fineness at its middle region, the amount of crowning of the first 
refining roller 6 shall have to be increased and, if necessary, also the 
amount of crowning in the other refining rollers is to be increased 
proportionally. 
In the presence of a very flowable starting body, opposite adjustments to 
what is stated hereinabove must be effected with highly viscous or denser 
products. 
It should be enhanced here that to achieve an increase in output, it will 
be sufficient to increase the speeds of the gear motors 59, 60, 61, 62, 63 
associated with the rollers 4-8, leaving the speed ratii otherwise 
unaltered. In fact, an increase in the feed-in-rate would result in an 
increased chocolate paste demand by the machine, that is by the roller 
pair 5, 6, and accordingly, in an increased thickness of the chocolate 
film across all the rollers, including the last refining roller 8, whereat 
the increased thickness will be advantageously monitored by the cited 
colorimeter 55. 
The individual actions on pressure, speed, and crowning provided by this 
refiner may be either effected manually, that is by manually operating the 
corresponding controls, or through a microprocessor central unit control. 
The use of a microprocessor affords full automation of the refiner, whose 
operation may accordingly be piloted, e.g. by means of cards or routines, 
in accordance with the different chocolate types or pastes to be refined. 
Shown in FIG. 7 is a graph setting forth in principle the relationship 
between the viscosity or plasticity (expressed as fat percent in the 
chocolate paste) of a given chocolate paste, the pressure P in kilograms 
to be applied to the supports of the refining rollers, and the sum of the 
crownings a roller pair should have for the respective opposed 
generatrices of said rollers to be truly parallel in operation, that is 
when subjected to a given pressure load "P". 
FIG. 8 shows the thickness values for the product film being delivered at 
the delivery refining roller 8, as measured, for example, in a prior 
refiner having a fixed crowning, in the presence of a uniform or constant 
speed product throughout the measuring period and at different pressures, 
as specified. The side M denotes the motor side, the middle region is 
indicated at C, and the remote side to the motor side is indicated at O. 
The M-O segment denotes the roller length. It may be gathered from the 
graph that at a pressure of 4,500 kg a thickness is achieved of 18 .mu.m 
for the chocolate film over the entire width thereof. If the pressure is 
to be increased, in order to achieve a higher film fineness, an actual 
fineness decrease is determined in practice at the end regions of the 
chocolate film, while at the middle portion thereof a growing thickness 
increase is recorded due to a progressive hogging of the various refining 
roller pairs at the opposed generatrices thereof. 
To further explain the different influences of the various parameters on 
the machine performance, the graphs of FIGS. 9 and 10 reflect the 
relationships between the different parameters which are to be considered 
in connection with adjustment actions, namely viscosity, crowning, and 
pressure, in conjunction with other product parameters of determining 
interest, such as the product fineness, and operative parameters, such as 
the speed of the first roller, output rate in kg/hour, and viscosity of 
the starting product. The required conditions for the desired operation 
are set forth on an exemplary straight line. The individual symbols mean: 
o=preset values 
+=result aimed at 
xx=variable value 
*=actually achieved results 
.noteq.=intervening differences. 
In plotting the graphs, the following function f relations between the 
various parameters have also been taken into account: 
output Q=f speed of the feed-in roller pair, 
viscosity=f crowning and machine speed, 
crowning=f pressure on the rollers, 
fineness=f speeds of the feed-in roller pair and refining rollers. 
The full lines represent the settable parameters and the dash lines the 
consequent ones. In FIG. 9, the broken lines S1 and S2 denote the 
variations conceptually intervening for the various parameters considered 
as the viscosity, .mu.2 and .mu.3, of the chocolate paste being fed in 
varies, and specifically, in the vent of the same decreasing (S1) and 
increasing (S2). The distances between single points on the broken lines 
and straight line for balanced operation, that is illustrating the 
respective overall conditions for the desired operation, show the 
conceptual deviations of the respective parameters. 
The crowning-viscosity interrelation may be observed in FIG. 11. It is 
shown therein that the rolling pressure is directly proportional to the 
thickness differential between the thicknesses upstream and downstream of 
each roller pair. As the product viscosity increases, the boundary layer 
thickness also increases and the cited thickness differential with it, 
namely the pressure exerted by the product on the two rollers. To achieve 
uniform degrees of fineness, accordingly, the amount of crowning will be 
increased. 
FIG. 12 shows how hourly output is increased by increasing the speeds of 
the rollers--while keeping the ratii therebetween constant. That increase 
varies, however, as a function of the product viscosity. 
It may be appreciated from the foregoing description of the embodiments 
proposed and operation of the machine according to the invention that the 
latter can effectively achieve the object underlying the present invention 
and the advantages stated in the preamble. In particular, a refiner has 
been provided which has a highly flexible operation and can accommodate 
virtually any chocolate pastes in conditions as desired for each specific 
situation. 
In practice, it will be readily possible to replace individual parts with 
other technically and/or functionally equivalent parts, as well as to use 
servocontrols of any suitable types, without departing from the true scope 
of this invention. 
The oscillating supports for the rollers may also deviate from the two 
embodiments thereof given above by way of example, again without departing 
from the scope of the invention. 
Substantial to the invention is the provision in the same refiner of three 
individual control facilities, or combined facilities, as regards roller 
pressure, speed, and crowning. Also substantial is the provision of a 
central control unit with a microprocessor, in order to achieve operation 
conditions which are both fully automatizable and capable of providing the 
required results starting from materials which may be originally 
different. 
While reference has been made throughout the above description to chocolate 
as a prime material, it will be obviously understood that the inventive 
refiner may be employed with any mixtures or suspensions in the plastic 
state, irrespective of the non-Newtonian rheological characteristics 
thereof, such as with inks, paints, etc. 
All of the features which can be inferred from this specification, appended 
claims, and accompanying drawings are regarded as essential to this 
invention, either singly or in any combination thereof.