Note: Descriptions are shown in the official language in which they were submitted.
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AGGLOMERATION PROCES~S
T~le present invention is concerned with a novel process
for agglomerating carbohydrate materials. More particularly,
ithis invention is concerned with a novel process for contacting
a solid, pulverulent carbohydrate with water or an aqueous syrup
or solution of a carbohydrate under conditions suffieient to
produee a dry, free-flowing agglomerate. This invention is espe-
eially useful for forming dry, free-flowing agglomerates of
- suerose and invert sugar useful as an instant dry fondant which
is readily and quiekly reconstituted on mixing with water.
The agglomeration of sugar and other pulverulent solid
earbohydrates by eontaet of the solid with water or an aqueous
binder solution is well known. Sueh processes have been employed
to prepare, inter alia, icing sugars, brown sugars, milk products
and stareh produets, as well as produets useful as direct com-
pression tabletting vehieles, ete. In general, however, sueh
proeesses have entailed the
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use of complicated equipment and procedures in an effort
to achieve what apparently was believed to be the
necessary uniformity of agglomeration to yield a free-
flowing, non-caking, yet easily reconstitutable product.
S For example, in one such process, as disclosed
in U. S. Patent No. 3,305,447 to Reimers et al, granulated
sucrose and a binding agent are mixed under conditions of
turbulent shear and impact action in a mechanical mixer
known as the "Turbulizer." The resulting product is
described as being a substantially dry, homogeneous
granular admixture. However, the~product cannot be used
as such. Rather, as is taught by Reimers et al, the
product first must be pulverized, then compacted and
finally ground to form a product useful for tabletting
purposes.
In another process, disclosed in U. S. Patent
No. 3,518,095 to Harding et al, sugar and a binder syrup
are admixed in a high intensity mlxer such as a
Patterson-Kelly blender, under conditions of uniform
intermingling and distribution of the sugar and syrup to
form agglomerates, and rolling of the agglomerates to
form generally spherical, firm agglomerates. These
agglomerates are useful as dry fondants or as direct
- tabletting vehicles. See U. S. Patent No. 3,627,583.
The aforementioned procedures achieve mixing
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of the solid material and the liquid binder through the use
of equipment in which the`energy of mixing is imparted by`
means of solid stirrers or rotary mixing vessels, in which
impingement of the solid and the resulting agglomerate on
equipment surfaces is an essential feature.
Still other processes have involved spraying
syrups onto suspended particles of sugar. For example,
Armstrong et al, in U. S. Patent No. 3,391,003, disclose
spraying a liquid wetting agent onto particles maintained
in a fixed fluidized bed. The Armstrong et al product, by
virtue of being formed in a fluidized bed, inherently has
a uniform particle size. However, the process is relatively
inefficient in that a substantial proportion of the end
product comprises particles of unagglomerated solid feed. -?
This is undesirable where the agglomerate is composed of
two or more different materials, one supplied in the form
of a solid feed and another in the form of a liquid binder.
Unless the sizes of the product particles are extremely
; uniform, size-segregation of the product can occur, leading
to a product of varying composition.
French Patent No. 868,314 to the Pillsbury Co.,
also discloses an agglomeration process employing what is
essentially a fixed fluidized bed as the agglomeration
means. In this process, sugar particles supported on a
screen are slightly fluidized with moist air or steam to
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effect agglomeration. The bed, still suspended over thescreen is then transported successively through a hot air
drying chamber and a cooling chamber.
In still another approach, somewhat related to
- 5 the fluid bed techniques of Armstrong et al and Pillsbury,
Reimers et al, in U. S. Patent No. 3,143,478, disclose a
method involving contacting a falling curtain of pulverized
sugar with a moistening fluid, such as water, steam or
moist air. This process is carried out in two stages:
first, the particles are moistened with a low velocity stream
without causing turbulent movement of the solid particles;
; then the moist particles are contacted with a high velocity
gas stream to create turbulence and effect agglomeration.
Ordinarily, the resulting product must be dried in a
subsequent drying step.
In a related method, U. S. Patent No. 2,856,318
to Peebles discloses agglomerating lactose in a chamber by
allowing lactose powder to fall through a chamber wherein
it is contacted with a water spray and steam. In this
process, the flow of solid feed and agglomerates is
counter to the flow of air through the chamber. Despite
relatively long residence times (10 to 60 seconds), the
agglomerate has a moisture content of the order of 10-16
; percent.
As is evident from the above-cited references,
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the proceduresof the prior art all are relatively complex
and/or require relatively expensive equipment to achieve
the desired agglomeration.
- It is an object of the present invention to
provide a simple method for agglomerating sugar and other
solid, pulverulent carbohydrates.
It is another object of this invention to provide
a method for agglomerating sugar and other solid, pulverulent
carbohydrates which employs simple equipment.
Still other objects of the present invention will
be evident from the ensuing specification, exampLes and
claims.
In essence, the present invention comprises con-
tacting particulate sugar or other solid, pulverulent
carbohydrate which is entrained in pneumatic transport flow
in a carrier gas, typically air, with a spray of a binder
fluid, e.g., water or an aqueous binder solution, and
maintaining the resulting mixture of pulverulent solid and
binder fluid in pneumatic transport in the carrier gas to
form and carry off the agglomerates. This procedure is
most easily carried out by entraining the particulate solid,
e.g., sugar, in an air stream, passing the stream through
a conduit having mounted therein one or more nozzles adapted
to direct a spray of a liquid binder onto the entrained sugar,
and thereafter discharging from the conduit an agglomerated
product.
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More particularly, the invention relates to a method
for agglomerating a pulverulent solid carbohydrate with an
aqueous medium which comprises spraying said aqueous medium on-
to said solid entrained in pneumatic transport in a flowing gas
stream in a spray zone, the linear velocity of said gas
stream being in the range of from 2500 to 8000 feet per
minute, maintaining the resulting mixture of said aqueous
medium and said pulverulent solid entrained in pneumatic
transport in said gas stream for a period of time sufficient
to form said agglomerates, and removing said agglomerates
from said spray zone by pneumatic transport in said gas
stream.
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Figure 1 illustrates, in schematic form, equipment
which can be employed to carry out the process of the present
invention.
Figure 2 illustrates, in schematic form, an
alternate form of equipment which can be employed to carry
out the process of this invention.
In essence, the equipment comprises in combination,
a source of pulverized solid carbohydrate, e.g., sugar, a
source of entraining fluid, e.g., air, means for admixing
solid with entraining fluid, a conduit through which the
solid is transported in pneumatic flow by the entraining
fluid, a means for directing a spray of binder fluid, e.g.,
a sugar syrup, onto the entrained solid, means for separatïng
agglomerates from entraining fluid and, if necessary, means
for reducing the moisture content of the agglomerates.
As shown in Fig. 1, particulate solid (sugar)
and entraining fluid are transported from suitable sources
1 and 2 to a mill, such as a Bauer mill 3, where the
solid (sugar) is pulverized to form particles having the
sizes desired in the particular agglomerated product to be
made. The pulverized solid (sugar) is entrained in the fluid
(air) in the mill and the resulting admixture is discharged
into conduit 4. In Fig. 1, conduit 4 is shown as having a
generally vertical orientation, and the air and entrained
solids are shown as being passed upwardly through the
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conduit. This is not essential to the present invention,
and conduit 4 may hàve any orientation, including a hori-
zontal orientation, and the air-entrained solid stream may
be passed through the conduit in any direction, e.g.,
upwardly or downwardly through a generally vertical conduit.
The proportion of entraining fluid and solid, the particle
sizè of the solid and the fluid flow rate are all selected
so that the solid is swept through conduit 4 in pneumatic
flow, and substantial contact of solids with the walls of
conduit 4 is avoided.
A binder syrup is introduced into conduit 4
through nozzle 5, located in conduit 4 and spaced from
the inlet of conduit 4 from mill 3 a distance such that
turbulence resulting from introduction of the entrained
solid-fluid mixture into conduit 4 has subsided. The
spray particles from nozzle 5 impact upon the entrained
pulverulent solid, forming a liquid film on the surfaces
of the solid particles. As the moistened particles travel
through conduit 4 they contact one another, allowing the
formation of agglomerates to occur. The moistened particles
and the resulting agglomerates are entrained in and are
removed from the spray zone by pneumatic transport in the
flowing fluid stream. In addition, depending upon the
temperature of the entraining fluid, the temperature and
amount of binder liquid, and the residence time of the
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moistened particles and the resulting agglomerates in
conduit 5, drying of the agglomerates occurs to a greater
or lesser extent.
It is a feature of the process of this invention
that a highly uniform intermingling of liquid binder and
pulverized solid is readily achieved. As a consequence,
the composition of the agglomerates formed by this process
is surprisingly uniform, despite the fact that agglomera~es
whose particles have widely varying sizes may be formed.
In contrast, processes of the prior art produce agglomerates
of pulverulent solid and binder whose proportions of these
components can vary significantly with particle size.
It is a further feature of this invention that
agglomeration is effected substantially only by contact of
liquid and solid. The contact of solid and liquid with
equipment surfaces, i.e., conduit walls, is to be avoided
and plays little or no role in effecting agglomeration.
Still another feature of this invention is that
agglomeration and drying of the resulting agglomerate occurs
very rapidly. Ordinarily, residence time of the agglomerate
in the agglomeration apparatus employed to practice the
process of this invention is very short, of the order of 1
second or less, and yet relatively dry agglomerates,
containing of the order of 5 percent or less moisture, are
rèadily obtained.
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~ The agglomerates formed in accordance with this
invention are separated from the entraining fluid and, if
necessary, unagglomerated solids or undersized "dust,"
as by use of a cyclone separator 16. Optionally, the
agglomerates may be dried in dryer 17, following which
they are shipped to storage, to packaging operations, or to
any other suitable destination.
With reference to Fig. 2, an-alternate form of
apparatus comprises feed hopper 21, in which pulverized
sugar is contained, and an air intake duct 22. Sugar is
entrained in the air in duct 23, and the sugar-air mixture
fed to conduit 24, which is generally horizontal. As shown,
conduit 24 is slightly inclined to permit the conduit to be
washed out easily, and is provided with spray nozzle 25
at its lower end, through which binder syrup is introduced.
Conduit 24 may be of constant cross-section over its entire
length. Alternatively, as shown in Fig. 2, the initial or
mixing section 24a, in which nozzle 25 is mounted, may be
of enlarged cross-section to minimize the contact of spray
or still-moist agglomerates with the walls of conduit 24.
The balance of conduit 24 may be of reduced cross-section
(24b) to convey dried agglomerates away from mixing section
24a. The dried agglomerates are recovered from the air
stream in cyclone 26.
As is evident from the foregoing, the agglomeration
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1~86~)7
process of the present invention is much simpler in concept,
equipment and mode of operation than are the agglomeration
processes o` the prior art. Furthermore, by ensuring highly
uniform intermingling of binder fluid with pulverulent solid,
it provides agglomerates of remarkably uniform composition,
regardless of agglomerate size.
The process of this invention is to be distinguished
from that of Reimers et al, as disclosed in U. S. Patent No.
3,140,201. In this prior art process, a mixture of a solid
(sugar) and a binder syrup is introduced into a toroidal
grinding cha~ber, and is violently transported through the
chamber by air at sonic or supersonic velocity. The resulting
violent contact of the entrained agglomerates causes them to
be reduced in size and, after sufficient size reduction the
smaller particles are withdrawn through a classifying section.
By avoiding premixing of solid and binder, the process of
this invention avoids the need for co-grinding and, hence the
need for high velocity air found by Reimers et al to be
essential to affect size reduction. Further, in the process
of Reimers et al, agglomeration in effect occurs prior to
suspension in air; the air serves only as a transport medium
for ~ing and grinding. In the process of this invention,
the air serves as a transport medium for drying and agglomera-
tion. As a consequence, applicant's process employs simpler
equipment and does not require the use of high pressure air.
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As is evident from the foregoing, the process
of this invention relies essentially on the principles of
pneumatic transport. These principles are well known, and
- will not be further detailed here. Due to the simplicity
of th'is invention, these known principles may be simply
adapted through a few simple experiments to permit
aggl'omeration of any suitable combination of pulverulent
solid and binder fluid.
Solids which may be agglomerated in accordance
with this invention may vary widely. The process of this
invention is of particular value in producing agglomerated
food products from solids such as sugars of various kinds,
including mono-, di- or t'risaccharides such as arabinose,
xylose, ribose, fructose, mannose, galactose, sucrose,
maltose, lactose and the like, sugar alcohols such as
xylitol, sorbitol and mannitol, as well as other carbohy-
drates such as starch, or other solid food products such as
dried whole milk powder, dried cheese powder and the like.
Sugars are preferred for use as the solid. The solid can
be obtained synthetically, or it can be a refined natural
product such as corn syrup solids, molasses solids, honey
solids and maple syrup solids.
The sizes of the solid particles are not highly
critical, and depend upon the product desired and the
ability to transport the particles, and their agglomerates,
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in pneumatic transport. In general, the pulverulent solid
may have up to 80 weight percent of its particles having
sizes of up to about 35 mesh (Tyler series). For most food
products, smaller sizes, e.g., 85 percent or less below
80 mesh, are desired for proper taste or feel characteristics.
If the product is to serve as a dry fondant, the solid sugar
should be composed of particles, of which 99 percent have
sizes of less than 325 mesh.
The entraining fluid can be any gaseous substance
capable of entraining the pulverulent solid and supporting
pneumatic flow. To the extent the product agglomerates are
intended for use as food of pharmaceutical products, it
should also be non-toxic; and it should be essentially
inert to the materials being agglomerated. As a practical
matter, air is the ~eferred entraining fluid due to its
ready availability. On the other hand, gases such as
nitrogen, argon, etc., theoretically could be employed.
Because one function of the fluid entraining medium
is to dry the agglomerate, it is highly desirable that the
fluid have a relatively low moisture content. This may be
achieved through use of a heated fluid. For example, if
ambient air is the source of entraining fluid, the air is
; desirably heated, preferably to temperatures of the order
from about 150 to about 300F (65C to 150C), by any
suitable technique. Alternatively, or additionally, the air
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may first be treated in known manner to reduce its
moisture content.
The proportion of entraining fluid to pulverulent
solid is not highly critical, and will depend upon the
degree of agglomeration desired and the amount of drying
of the ~oduct agglomerate to be obtained during the process.
Obviously, the greater the ratio of fluid to solid, the
fewer opportunities there are for agglomeration to occur.
On the other hand, if the density of the pneumatic solid-
fluid system is too great, efficient operation of the processof this invention, in particular drying of agglomerates, may
be hindered. Further, the amount of fluid will depend upon
the amountof moistu~e in the fluid itself, or introduced
with the binder. To achieve the same degree of dryness in
the agglomerate product, greater quantities of and/or
warmer streams of fluidizing medium must be employed to
efféctively remove the greater moisture burden. In general,
however, densities of from about 0.003 to about 0.03 pound
of pulverulent solid per cubic foot of entraining fluid,
e.g., air, are employed. Densities of from about 0.01 to
about 0.02 pound solid per cubic foot of air are preferred.
The velocity of the fluid through the conduit is that velocity
which is sufficient to entrain the solid and transport the
solid in pneumatic flow. To achieve high density agglomerates,
linear velocities in excess of about 2500 ft./min. should be
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~86(~7
14
employed, with linear velocities in excess of about
4000 ft./min. being desired to minimize the possibiiity
of settling of larger particles and the need to clean the
apparatus. Linear velo~ities in the range of from about
6000 to about 8000 ft./min. are especially preferred.
The conduit employed in practicing the process
.
of this invention may be made of any suitable material and
it may have any desired cross-section. ~s is noted above,
the conduit is preferably vertically oriented and it
should be substantially straight to limit the opportunity
for agglomerates to contact conduit walls, especially in the
region at and shortly downstream from the spray nozzle.
Cylindrical conduits are preferred. Similarly, the size
(i.e., diameter and length) of the conduit is not highly
critical. The diameter is largely a function of the amount
of solid material to be processed in a given time period,
and the ability to maintain stable pneumatic flow. Further,
the conduit should be sufficiently wide to permit intro-
duction of the binder spray without significant wetting of
the conduit walls in the neighborhood of the spray. In
general, it has been found that the minimum cross-sectional
dimension of the conduit should be in the range of from
about 5 to about 15 inches (12.7 to 38.1 cm), and preferably
from about 8 to about 11 inches (20.3 to 27.94 cm).
The binder medium which is employed in accordance
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with this invention is any`liquid which, when it contacts
the pulverulent solid particles, causes them to have tacky,
sticky, adherent surfaces. Thus, the binder may be a
solvent for the solid, and in the event the agglomerate is
intended for human consumption, a non-toxic solvent is
employed. As a practical matter, water is employed as the
solvent. It is a good solvent for many materials, it is
inexpensive, it is non~toxic, and it is not so rapidly
evaporated that sufficient time to form agglomerates will
be precluded. It is preferred, however, that the binder
include dissolved adhesive substances, in addition to the
solvent, to enhance adhesion and therefore agglomeration.
Such adhesives include polyhydrGxy compounds, such as
propylene glycol, glycerol, erythritol, arabitol, xylitol,
adonitol, mannitol, dulcitol, sorbitol, sugars such as
arabinose, xylose, ribose, glucose, mannose, fructose,
sucrose, maltose, lactose, dextrose and the like, as well
as gums such as agar, carageenin, locust bean, guar and
the like. Mixtures of two or more binding agents may be
employed. Invert sugar is preferred when preparing instant
dry fondant from pulverized sucrose. Natural syrups or
other natural or even refined products may be employed,
including corn syrup, molasses, honey, maple syrup and the
like. Where an aqueous solution is employed as the liquid
binder medium, the concentration of binder solid is not
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highly critical. In particular, highly supersaturated
solutions, such as those requirèd by Gillett et al, U. S.
Patent No.~2,824,808, are not r~quired. In general, the
concentration of the solids in the binder fluid or syrup is
a function of the solubility of the solute, and the
viscosity and sprayability of the solution, which in turn
is dependent upon the temperature of the solution. Other
factors are the drying capacity of the agglomerator, the ~
desired levels of water and solid binder in the final
agglomerate and the temperature of the entraining fluid.
In general, however, the solution will contain no more than
85 weight percent dissolved solids.
As a general rule, the ratio of water to total
solids, including solids in the aqueous binder medium,
should not exceed about 20 parts water per 100 parts solid.
; If the solids are water soluble, then smaller amounts of
water are preferred. For example, when spraying an invert
syrup onto pulverized sucrose, the total amount of water
ordinarily should not exceed 6.5 parts per 100 parts of
solids. The reason for the use of smaller amounts of
water is that, by dissolving a portion of the solids, the
total effective solid surface area involved in the agglomera-
tion process is reduced. Therefore, the amount of liquid
(solution) phase must be reduced in proportion to the decrease
in solid surface to permit effective agglomeration and
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drying of the resulting agglomerates. In the case of
invert syrups, syrups having a range of from about 25 to
` about 85 Brix and from about 25 to about 70 weight percent
- invert have been found useful. In the case of aqueous
gum solutions, gum concentrations of from about 1 to about
3 weight percent are normally employed.
The liquid binder is desirably at an elevated
temperature, especially when the liquid binder is a syrup
or solution. In this way, the viscosity of the solution is
reduced to facilitate spraying. The temperature should not
be so high, however, that crystallization is induced through
cooling when contacted with much cooler air or other
entraining fluid, nor should it be so great that flash
evaporation of the solvent occurs, thereby precluding
agglomeration altogether. Ordinarily, the temperature of
the binder liquid should be greater than that of the entrain-
ing fluid, and temperatures of the order of from about 120F
to about 200F (50 to 105C) have been found useful.
The binder liquid is sprayed on the entrained
pulverulent solid in any convenient manner, as by use of
one or more nozzles in the conduit wall or positioned in the
conduit. If a single nozzle is employed, it preferably is
positioned at the axis of the conduit and oriented to direct
the spray downstream, i.e., in the direction of flow of
pulverulent solid. If the nozzle is directed upstream, it
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rapidly becomes coated with solid and spray. Several
nozzles arranged around the wall of the conduit may be
employed if desired. The nozzle may be of the airless or
the pneumatic type. The æize of the droplets of the binder
spray is not narrowly critical, and can vary depending upon
the desired size of the agglomerates, with increased droplet
size giving larger agglomerates. In general, droplets of
the order of from about 5 to about 50 microns have been
found suitable.
The length of the conduit following the spray zone
is not highly critical. It provides a zone for further
agglomeration and drying of the agglomerates. In general,
for a conduit having a width of 8 to il inches, it has
~- been found that useful results are obtained where the spray
zone is located 4 to 6 diameters from the inlet end and the
total length of the straight section of the conduit is of the
order of 40-50 diameters.
The residence time of the agglomerate is a function
of air velocity and conduit length. In accordance with this
invention,it has been found that drying occurs virtually
instantaneously with residence times of 1 second or less
providing effective drying. If desired, residence times of
up to 5 seconds or even higher can be employed, but
ordinarily such long residence times are not required.
` As is noted above, the agglomerates which are
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formed in accordance with this invention are separated
from the entraining fluid, further dried if necessary, and
then sent to storage, bagging or other operation. The
agglomerates are typically smaller in size than agglomerate~s
formed by other processes. Nonetheless, they are free-
flowing and non-caking, and they can be readily reconstituted
by admixing with water. Because of the relatively low
particle size, dry instant fondant prepared by the process
of this invention can be used in lesser amounts than prior
art dry fondants to make a creamy fondant of comparable
consistency.
Having generally described the invention, the
following examples are presented as being illustrative of
the practice of the present invention. Although they will
pertain to the manufacture of dry fondant, the procedures
can be readily adapted to form other agglomerates, including
icing sugar, brown sugar, flavored flour, starch, enriched
wheat flour and other similar products.
Example 1
The apparatus comprised a Spray Systems No.
; 200278-45 nozzle axially mounted in an 8-inch diameter,
vertical duct of circular cross-section, having a length of
about 45 feet. Pulverized sucrose (99% less than 325 Tyler
mesh) entrained in warm air at 170F was passed upwardly
through the duct at a rate of 1740 pounds of sucrose per hour.
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The air velocity was about 7000 ft./min., providing a
residence time of entrained solids in the duct of less
than 1 second. An invert syrup (72 Brix, 54% invert
sugar) at a temperature of 140F was sprayed at a rate of
318 pounds per hour into the duct in the same direction
as the flow of the air-entrained sucrose. The spray was
in the form of a flat spray. The product was collected
in a cyclone and transferred to a dryer operating at
200F or 95C. The sieve analysis of the product was:
Retained on 20 Mesh - 0.9
Retained on 80 Mesh - 19.1~
Retained on 120 Mesh - 25.7%
Less than 120 Mesh - 54.3%
The less than 120-mesh fraction contained 13.8~ invert
sugar, and was found on microscopic analysis to be composed
primarily of agglomerates. Analysis of the product showed
16~ invert in the total product and 13.8~ invert in the minus
120-mesh fraction, confirming that even the fine particles
were agglomerates. On reconstitution with 100 parts solids
to 12 parts water, all but about 1~ reconstituted in 2
minutes. The product was found to be free-flowing and non-
caking after storage in 35-pound bags on pallets staked 8
bags high fox 15 months under ambient conditions.
~ le 2
Employing the apparatus and procedure described
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in Example 1, an invert syrup (72 Brix, 18% invert) was
sprayed~at 142F and 400 lb./hr; onto air-entrained
pulverized sucrose at 170 and 1250 lb./hr. There was
obtained a dried agglomerate similar to that of Example
1, which contained 8.1% invert and 0.75% water. The
product was free-flowing and non-caking after storage in
35-pound bags on pallets stacked 8 bags high for 14 1/2
months under ambient conditions.
Example 3
The apparatus described in Example 1 was employed,
except that a nozzle designed to give a conical rather than
a flat spray (Nozzle No. 49267650) was employed. The
pulverized sucrose was charged at 170F and a rate of
1140 lb./hr. and the syrup (72 Brix and 18% invert) was
charged at 190F and 420 lb./hr. The dried agglomerate
contained 11.8% invert and 0.98% water. Prior to drying,
the product contained 9.4% invert and 2.48% water. The
; product was free-flowing and non-caking after storage in
35-pound bags on pallets stacked 8 bags high for one year
under ambient conditions.
Example 4
The apparatus consisted of a 40-foot long by
8-inch diameter vertical duct having a circular cross-
section and an axially-positioned Spraco No. 49267640
nozzle located 5 feet from the bottom of the duct.
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Pulverized sucrose was charged at 170F and a rate of
2460 lb./hr. and syrup (66.5 Brix, 58.7~ invert) was
charged at 190F and a rate of 270lb./hr. There was
obtained a dried agglomerate having 6.67% invert and 1.30%
water and a screen analysis of:
Retained on 20 Mesh - 3.4%
Retained on 90 Mesh - 27.0%
Retained on 200 Mesh - 41.8%
Through 200 Mesh - 27.8%
The product was reconstituted with water in 2 m~nutes. On
storage in a 35-pound bag for 1 month at 40F under 1 lb./
sq. inch pressure, the agglomerate took soft set, but
resisted sericus caking. Similar results were observed
after storage under these conditions for a total period
of 9 months.
Examples 5 - 7
A series of three experiments was run in an
apparatus of the type shown in Fig. 2, employing a Spraying
Systems No. 60100 nozzle axially mounted in a 6-inch square
duct inclined at an angle of about 3 degrees from the
horizontal. The duct was 6 feet long, and the nozzle was
positioned about 3 feet from the feed hopper. The downstream
end of the duct was connected to a 30-foot long, 4-inch
square duct.
In each experiment, pulverized sucrose (99~ less
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than 325 Tyler mesh) entrained in warm air was passed
through th~e duct and was sprayed with invert syrup in
the form of a full cone spray in the same direction as
that of the air-entrained sucrose. The agglomerated
sucrose and invert product was collected in a cyclone
and analyzed for moisture and invert sugar content and
particle size distribution. The residence time of solids
in the duct was less than 1 second.
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The data for these experiments are summarized
` as follows: -
Table I
Example
Experimental Conditions 5 6- 7
Sucrose:
Feed rate, lb./hr. 480 452 485
Air: -
Temperature, F 192 219 208
Linear velocity, ft./min. 3888 3888 3975
Invert Syrup:
Brix 72 72 71.5
Percent Invert ~ 32 36.4 46
Temperature, F 146 158 154
Feed rate, lb./hr. 83.5 106 102
Ratio of Syrup to total weight
of Sucrose and Syrup, ~ 14.8 19.0 17;4
Spray Conditions:
Air pressure, psi 50 50 50
Rate of air flow through
nozzle, ft3(ambient air)/min. 11.4 11.2 11.2
Spray pressure, psi 40 43 43
Product Anal sis:
Moisture, weight % 1.3 0.9 0.9
Invert sugar, weight % 5.6 7.4 8.6
Sieve Analysis:
Retained on 20 Mesh 1.0 2.1 1.2
Retained on 80 Mesh 28.0 20.1 27.1
Retained on 140 Mesh 33.4 27.9 30.8
Less than 140 Mesh 37.5 49.2 40.9
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