Note: Descriptions are shown in the official language in which they were submitted.
A~ hRAlUS FOR SEAL]NG CAPSULES
The present invention relates to the prepara-tion of
capsules, such as may contain edible ingredients and
comprise telescopically engaged capsule halves, and more
particularly to an apparatus for permanently sealing such
capsule halves to each other to render the capsules
tamper-proof and tamper-evident.
The caps~les with which the present invention is concerned
are well known and have been in broad use for many years.
Such capsules are generally prepared from an edible
natural substance such as gelatin, and are generally
cylindrical telescopically engaging tubes, each tube
having one end thereof sealed, so that upon coaxial
disposition, they are capable of holding a quantity of
material. Generally, such capsules are utilized in the
pharmaceutical and food industries, to hold edible and
pharmaceutically active materials such as medicines,
vitamin preparations, and other edibles both solid and
liquid. The materials from which the capsules are
prepared are usually hydrophilic, and thereby adapted to
dissolve in the intestine after ingestion.
One of the difficulties that has long been encountered in
the use of such capsules as stated, has been their
ability and occasional tendency to disengage from each
other, whereby the contents of the capsule escape and are
lost. Accordingly, the prior art is replete with numerous
approaches directed to the maintenance of the sealing
engagement between the capsule halves.
The problem of the disengagement of the capsule halves
from each other has recently become more acute, in view of
the well publicized deliberate disassembly of certain
encapsulated medicaments and the inclusion therein of
certain poisons such as cyanide. This deliberate act was
~$
. .
~6~
successfully acc(~lnplish~d b~(~3u ~ cal-sules were
inadequately sealed and gave no evidellce of their
tampering. That is, the slip fit engagement between the
capsule halves was easily disrupted and the cap part of
the capsule was removed, so that the intruder WdS able to
insert a small but lethal quantity of poison or other
disruptive agent therein.
The events described above have spurred a renewed interest
on the part of the industry and the public at large to
develop methods and associated apparatus to render these
capsules tamper-proof by the placement of appropriate
indicators of tampering on the capsule. One such approach
to this problem has been known for some time, and is
disclosed in U.S. Patent No. 1,861,047. In this patent, a
circular band of hardened gelatin is disposed about the
seam that occurs ~etween the respective capsule halves
comprising the body and the cap part that receives it.
The application of the hardened gelatin band is presumed
to act as a capsule seal and tamper indicator, to indicate
when the capsule parts have been separated so that
evidence of tampering is visually apparent.
The procedure outlined in the '047 patent and the capsules
treated thereby have been found to be deficient, however,
as it was possible to separate the body part from the cap
part, modify the contents theréof and thereafter replace
the cap and body parts in position against each other and
reband the rejoined capsule so as to avoid detection of
tampering.
Further deficiencies in the aforementioned technique
relate to the material used to form the band. Generally,
gelatin is utilized and it is found that the application
thereof is dif~icult to control, with the result that the
bands initially applied are frequently irregular, split,
intermittent in extent and generally non-uniform in
~L2~ ga~
appc(~ n . . I~ lso, t~le a~ catlon o~ e gelatin t)and
tends to i~l~r~dllce moisture into the capsule contents
which in the instance of most capsule ingredients causes
instability, and correspondingly drastically reduces shelf
life of the contents. Likewise, if the drying system
utilized in conjunction with the application of the
gelatin band fails to function properly, excessive wetting
of the capsule at the site of the band and consequent
capsule deformation, particularly after large quantities
of capsules are discharged into a holding drum, in
accordance with conventional manufacturing
practice,accentuates capsule deformation and results in
increased numbers of capsule rejects.
Another bonding technique in broad use presently, is
essentially a branding procedure, wherein a heated probe
is applied against the outer surface of the capsule cap
portion with sufficient pressure to urge it against the
adjacent wall of the capsule body, and to cause both to
melt superficially and thereby bond to each other.
This technique has the drawback that it frequently causes
capsule deformation, by virtue of the localized heating
which can contribute to increased frequency of capsule
rejects. Likewise, the nature of the bond formed by this
procedure is extremely local and renders the capsule
vulnerable to undetectable vioiation, as with a scalpel or
needle probe, to facilitate disengagement of the capsule
halves for introduction of an adulterant~
Both of the aforementioned techniques are also inefficient
and costly, as the equipment in the instance of the
banding technique, is extremely expensive and limited in
its rate of output. Likewise, the equipment utilized in
the branding technique is complex, as one must have in
addition to the branding equipment, a separate low speed
machine ~or the purpose of holding the capsules during the
branding process.
.
~2~
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In copending Canadian Patent Application S.N. 454,863 -
Graham, filed May 22, 1984, a method for permanently
sealing capsules is disclosed which utilizes capillary
infiltration of the interstitial space between the over-
lapping walls of the assembled capsule. One of several
suitable adhesion-promoting fluids for the capsule wall
material is applied and thereby located within the inter-
stitial space, after which the capsules are exposed to
dielectric energy, such as by microwave heating, to bond
the contigugous capsule walls to each other. The
adhesion-promoting fluids include liquids having high
dielectric constants, such as lower alcohols.
In conjunction with this new technique it has been
determined that an apparatus would be desirable that
would facilitate the rapid, uninterrupted sealing of
large numbers of capsules on a commercial scale. As
no such apparatus capable of continuously performing
the aforesaid operations is known, the present invention
is believed to provide an apparatus that is parti-
cularly responsive to this need.
In accordance with the present invention, an apparatusis disclosed for the permanent bonding of the telescop-
ing halves of capsules prepared from resinous mate-
rials, and comprises a longitudinally extended base
having an infeed end and a discharge end; a con-
veyor means mounted on the base and extending from
the infeed end to the discharge end, for the move-
ment of capsules disposed thereon; capsule dispenser
means for holding a quantity of capsules to be treated,
located in communication with the infeed end; fluid
applicator means for applying an adhesion-promoting
fluid to the outer surface of said capsules
located downstream of said capsule dispensing
~;~6~9~
m~dllS; at l~ast one capsule ~ashing nleans for rirlsing
excess adhesion-promoting fluid from said capsules located
clownstream nf said app1ying means; drying means
downstream of said capsule washing means; dielectric
energy means located downstream of said drying means; and
collecting means located downstream of said dielectric
energy applying means, for collecting and either holding
or otherwise handling the finished capsules.
The capsule dispenser means may comprise a hopper into
which the unsealed capsules are charged for uniform
distribution along the conveyor means. In such instance,
a vibrating adjustable hopper may be uti1ized. The fluid
applicator means may comprise a spray dispenser assembly
having a dispenser head with at least one and preferably
multiple dispenser ports, positioned to direct a spray of
adhesion-promoting fluid against the capsules as they pass
by the spray dispenser assembly on the conveyor means.
Alternately, the fluid applicator means may comprise a
fluid bath containing a quantity of the adhesion-promoting
fluid and the conveyor means may be adapted to pass
through the bath. In similar fashion, the capsule washing
means may utilize similar assemblies to tne fluid
applicator means. Moreover, both or all units may be
identical or different as indicated, within the scope of
the invention.
The drying means of the invention may comprise an air
tunnel through which the conveyor means would pass, and
air circulating means, such as a fan or blower may be
associated with the tunnel to assure that a constant flow
of air passes therethrough. Where desirable, a heater may
be associated with the air circulating means so that
heated air is utilized in the air tunnel. In such
instance, a temperature regulator may be included so that
temperature may be varied to suit the specific capsules
being treated.
.. ,. . . . .... . .. ~ . ~
~2~
The dielectric energy means m~y colllprise an oven with a
chamber having an inlet and outlet end positioned to
permit the conveyor means to pass through the chamber. A
dielectric energy emitter such as a radio frequency unit
or microwave heating unit is located within the chamber
and positioned to direct the respective form of wave
energy against the capsules as they pass through3 to
promote the bonding of the adjacent capsule halves.
The collecting means may be a receptacle or other capsule
handling equipment, in the instance where the capsules are
immediately transferred from the present apparatus to
another station where they are packaged and shipped.
Alternately, the collecting means may be a receptacle for
holding a quantity of capsules after they are processed.
In the instance where the capsules contain liquids, the
collecting means may be adapted for transfer of the
capsules to the infeed end of the apparatus, to permit the
treatment of the capsules to be repeated.
In a further embodiment, the conveyor means may comprise a
single conveyor or plural conveyors. In the latter
embodiment, a first conveyor may extend from the infeed
end in communication with the dispenser means, and beyond
the drying means to a discharge end. A second conveyor
may be positioned in communication with the discharge end
of the first conveyor and adapted to pass through the
dielectric energy means. A particular construction
illustrated herein, positions the second conveyor beneath
the first conveyor with its direction of travel adapted to
be opposite to that of the first conveyor and in the
direction of the infeed end of the ~atter.
~dditional equipment may be included in accordance ~ith
the present invention. For example, the fluid applicator
means may be provided with fluid chillers, solvent
-- 6
3l~6~8~L
--7--
recovery tanks and washing systems, in the instance
where continuous commercial operation is involved,
and, with respect to the chiller systems, it is desired
to apply the adhesion-promoting liquid at a lowered
temperature. Multiple capsule washing stations may be
employed in the instance a wash solution is required
to assist in the removal of excess adhesion-promoting
fluid dispensed by the fluid applicator means, prior
to the removal of all treatment fluids.
Similarly, the drying means may be constructed with a
variety of components, and may operate by vacuum, infra-
red heat or simply the circulation of warm air, for the
purpose of removing the remaining traces of adhesion-
promoting fluid and washing fluids, as will be described
hereinafter.
The present sealing apparatus is capable oE high speed
operation, and may process as many as 1 million capsules
per hour. The apparatus is of simple construction and
operation, so that maintenance and other operating costs
are favourably minimized. Moreover, the employment of
dielectric heating with power units that may range
between 10 and 15 kW, assures that energy requirements
are likewise favourably reduced. The present apparatus
is naturally most effective when utilized in accordance
with the method outlined in the earlier referenced co-
pending Canadian Patent Application, S.N. 454,863.
Accordingly, it is a principal object of the present
invention to prepare an apparatus for sealing tele-
scopically assembled capsules.
It is a further object of the present invention to
provide an apparatus as aforesaid that operates rapidly
and achieves a permanent bond between the respective
overlapping capsule halves.
It is a still fur Lher ~b jecl of the present invention to
provide an appdratus as aforesaid that is of simple
construction and operation.
It is a still further object of the present invention to
provide an apparatus as aforesaid that is inexpensive to
operate.
Other objects and advantages will become apparent to those
skilled in the art from a review of the ensuing
description considered with reference to the following
illustrative drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic view of an apparatus in accordance
with the present invention.
FIGURE 2 is a perspective view of an apparatus in
accordance with an alternate embodiment of the present
invention.
DE~AlLtU Ut~(;K~ UN
~eterring now to the ~rawings, an~ initially to E~GURE 1,
the capsule sealing apparatus of the present invention
comprises a longitudinally extended base 2 having an
infeed end 4 and a discharge end 6. A conveyor means 8 is
mounted upon base 2 and extends from infeed end 4 to
discharge end 5 as shown. A capsu1e dispenser means 10 is
shown above infeed end 4 and is thereby adapted for
communication with conveyor 8. Capsule dispenser means 10
may hold a quantity of capsules not shown herein, and is
adapted to discharge a uniform number of such capsules
onto the conveyor means 8.
. ~ .. . .. . ...
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A flLIicl ap~)licator mearls 12 communicates with conveyor
rneans 8 and is positioned downstrealil of capsule dispenser
means 10. Fluid applicator means 12 applies an
adhesion-promoting fluid to the capsules as they travel
therepast. At least one capsule washing means such as
capsule washing means 14 is positioned adjacent and
downstream of fluid applicator means 12,in communication
with conveyor means 8. In one embodiment of the operation
of the present apparatus capsule washing means 14 is
adapted to dispense a quantity of a washing fluid or other
solvent that will remove the excess of adhesion-promoting
fluid applied by the fluid applicator means 12. In an
alternate embodiment, discussed in greater detail later
on, plural capsule washing means 14 are present, the first
in sequence used to dispense a fluid to assist in the
removal of the adhesion-promoting fluid, and the next in
sequence serving to remove all treatment fluids from the
outer surfaces of the capsules.
The present apparatus also includes a drying means 16
likewise communicating with the conveyor means 8 and
disposed downstream of capsule washing means 14. Drying
means 16 is provided to remove the excess moisture or
fluid that may remain either outside or within the
capsules after they emerge from capsule washing means l~o
A dielectric energy means 18, iocated downstream of drying
means 16 and in similar communication with conveyor means
8 is positioned to receive the dried capsules emerging
from drying means 16, and to expose the capsules to
dielectric energy to cause the bonding of the adjacent
overlapping capsule wall surfaces, in accordance with the
technique outlined hereinafter. Lastly, a collecting
means 20 is disposed in communication with discharge end 6
and thereby receives the capsules emerging ~rom dielectric
energy means 18, for storage, shipment or further
processing.
- ~6~
~eferrirlg further to FlGll~E 1 in detail, the present
apparatus is schematically depicted, and the base 2 can be
seen to comprise an essentially longitudinally extended
table or the like offering a continuous horizontal support
for the present apparatus. The conveyor means 8 comprises
an endless belt 22 which may be motor actuated by means
not shown herein. Likewise, the specific conveyor means
rnay vary in accordance with the differin~ conveyor
constructions already known and commercially available.
No attempt is therefore made herein to set forth a
specific conveyor as the present invention is not limited
to a particular conveyor construction for its operation.
Capsule dispenser means 10 may comprise a hopper 2~ which
is provided with a conventional constriction at the bottom
thereof for the release of capsules upon belt 22. In
particular, a vibrating hopper may be chosen and used,
which is adapted by its operation to dispense a uniform,
single layer of capsules upon belt 22. In this way, each
of the capsules is likely to receive the same treatment as
it passes through the apparatus.
Th~ fluid applicator means 12 comprises a fluid spray
dispenser assembly 26, having a dispenser manifold 28
positioned so as to extend over belt 22. One or more
dispenser ports 30 (one only illustrated~ are provided
along manifold 28 and are adapted to direct a spray of
adhesion-promoting fluid downward against the capsules as
they are fed past assembly 26.
Spray assembly 26 may be covered by a spray shield 32 as
illustrated, that may be appropriately vented in a manner
not illustrated herein, to prevent the undue generation of
airborne effluent in the instance where it is desirable to
limit the escape of the adhesion~promoting fluid into the
atmosphere. In the instance where the adhesion-promoting
-- 10 --
~%~
fluid is exp10sive as in the inst~ !here hY~dne ~r
petroleum ether are ~tilized, the entire spray dispenser
assembly 26 can be appropriately enc10sed and made
explosion-proof by appropriate insulation, and hy the
installation of other safety equipment known in the art.
Spray dispenser assembly 26 may also include a solvent
tank 34 that would operate in conjunction with dispenser
manifold 28, to provide a constant, and if desired,
recirculating supply of the adhesion-promoting fluid. In
such 1atter instance, appropriate drains may be disposed
adjacent belt 22, to permit excess adhesion-promoting
fluid to run off and to return to solvent tank 34.
Capsule washing means 14 may be similarly constructed to
capsule dispenser means 10, and may therefore include a
spray dispenser assembly 36, a dispenser manifold 38, a
dispenser port 40, a spray shield 42 and a solvent tank 44.
Each of these components would operate in like manner to
the comparable components discussed above with respect to
fluid applicator means 12, with the only difference being
that, at this station, a quantity of a washing fluid or
solvent would be sprayed over the outer surface of the
capsules to remove excess adhesion-promoting fluid,
leaving the adhesion-promoting fluid in the desired
location between the capsule halves.
As discussed earlier, plural capsule washing means 14 may
be employed where a first wash with a solvent of the
adhesion-promoting fluid is desirable to initiate the
removal of the latter from the capsules. Thereafter, the
capsules can be finally washed with a washing fluid as in
accordance with the procedure a1ready discussed, to remove
all adhesion-promoting fluid and in this instance
additional solvent, from the surfaces of the capsules.
~2Ç~0~
Thus, ~/nile a single cal-sule ~iashi~ S is illustrated,
it is to be understood that a second spray dispenser
assembly such as assembly 36 may be positioned alony belt
22 downstream ~rom assembly 36 as illustrated, so that the
illustrated assembly 36 would apply the solvent solution
for the adhesion-promo-ting fluid, and the second spray
dispenser assembly would apply the washing fluid or
solvent as discussed earlier on herein. Thus, while the
installation of plural capsule washing means 14 is not
illustrated as such installation per se is believed to be
within the skill of the art, the provision of the plural
units as discussed above is within the scope of the
invention.
While both fluid applicator means 12 and capsule washing
means 14 have been illustrated herein with reference to a
spray dispenser assembly, it is possible that the
respective stations may comprise treatment tan~s or
troughs through which the conveyor bearing the capsules
may pass. In such instance, the conveyor may be modified
in a number of conventional ways to assure that the
capsules remain uniformly dispersed as they pass through
the bath. For example9 belt 22 may have a series of
regularly spaced, transverse partitions or barriers~ to
assure that a regular number of capsules remain within a
given area on the belt. Alternate1y, the belt may pass
through the bath at an extremely slight acute angle, so
that the capsules would be unlikely to conyregate on the
conveyor and, perhaps to fall off the conveyor and into
the bath. Thus, while not specifically shown herein, the
present invention is believed to include within its scope
alternate fluid dispensing means to those illustrated
herein.
Referring further to FIGURE 1, drying means 16 located
downstream of the capsule washing means 14, receives the
fluid-treated capsules and removes excess moisture from
their S~rfd((' . bf'j',il',, In(`d~ colnilrises an air t~inn~-l
46 tha-t ~x~end. lor,gitu~linally over belt 22, and pro~ides
for the circul~tion of a flo~ of air past the capsules to
dry them out. Tunnel 46 as illustrateda develops a f~ow
of air (shown by the small arrows) that is countercurrent
to the direction of travel of the capsules along belt 22
(belt travel direction illustrated by the larger arrow).
Thus, tunnel 46 has an inlet plenum 48 which, while not
illustrated herein as such, may be of increased size, to
receive the initial flow of circulating air therein.
Similarly, outlet or exhaust plenum 50 is located at the
opposite end of tunnel 46 and represents the point at
which the air flow is recirculated or otherwise exhausted~
Tunnel 46 as illustrated in FIGURE 1 is a recirculating
system, having a circulating means or blower 52 positioned
adjacent inlet plenum 48. Optionally, a heating means or
heater coil 54 may be positioned upstream of blo~er 52, in
the instance where it is desired to circulate heated air
through tunnel 46. Heating means 54 may be appropriately
regulated by a thermostat, not shown herein, so that the
exact temperature of the circulating air may be precisely
controlled. In this way drying temperatures may be
modified to suit different capsule products being sealed.
Also, the relatively moisture-laden air leaving tunnel 46
may be appropriately dried out by passage through heating
means 54, so that, if desired, drying means 16 may operate
in closed-100p fashion. Naturally, however9 the invention
is not limited to this specific construction and
operation, as the tunnel 4& may receive heated air from a
separate source and may not necessarily operate by air
recirculation.
Dielectric ener3y means 18 is located to receive conveyor
belt 22 as shown, to cause the final bonding of the
capsules, in accordance with a process described briefly
later on herein. Dielectric energy means 18 comprises a
- 13 -
~6~
,liell t~ic o~en ~, h~ving an ~ " Il,let r)~ dn(i ~n oven
oulle~ f,0 thdt are adapted to receive belt 22 bearing the
c~psules thereon. The interior of oven 56 comprises an
oven chamber 62 having d dielectric energy emitter 6~
shown schematically. A variety of dielectric ovens may be
suitable for the purpose of sealing capsules, and~ for
example, dielectric energy emitter 64 may be adapted for
the emission microwave energy, or radio frequency wave
energy, at a variety of energy levels. In the instance
where gelatin capsules containing powdered medicaments are
being sealed, the energy emitter 64 may be set to emit
energy through a range of 10 to 15 kW. This level has
been found to be sufficient for a throughput of 1 million
capsules per hour, which is a substantially greater
processing capacity than is available with any apparatus
known presently. Capsule residence time is extremely
brief and the capsules emerging from oven 56 are
completely sealed.
After emerging from dielectric energy means 1~, the
capsules reach discharge end 6 where they are deposited in
a collecting means 20, which may be simply a receptacle 66.
From this point, the capsules may be stored for further
processing or may be transferred for packaging and
shipment. In the instance where capsules containing
various liquids have been treated by passage through the
present apparatus, it may be désirable to repeat the
treatment a plurality of times to assure 100% fluid-tight
sealing of the capsule halves. In such instance, the
collecting means 20 may comprise a conveyor or other
transport means not shown herein) that may automatically
return the treated capsules to capsule dispenser means 19
for a further pass through the apparatus. The specific
construction of such an alternate collecting means may
vary within the scope of the present invention.
- 14 -
~L21E~013~
lhe t~p~ ,tlls ill~lstra~e(l ~cilelna~ic~lly in FIGURE 1 and
describ~d in detail above is but one embodiment of the
present invention. Referring now to FIGURE 2 an alternate
embodiment of the invention, however clearly within its
spirit and scope is illustrated in perspective. Referring
now to FIGUXE 2, an apparatus is shown which utilizes as
its primary distinction from the apparatus of FIGURE 1,
two conveyors as part of the conveyor means 8. Thus, a
first conveyor 72 is shown which is disposed on an
independent primary base 74 and extends from an infeed end
76 commencing just before hopper 78, and extending to a
discharge end 80, situated beyond air tunnel 82. A second
conveyor 84 is shown that extends below first conveyor 72
and is adapted to travel in the opposite direction,
through dielectric oven 86, where it terminates at a
collector 88. Second conveyor 84 has an infeed end 90
which is adapted to receive the capsules ~rom discharge
end 80, and a discharge end 92 from which the finally
treated capsules may pass to collector 88. As shown,
discharge end 80 and infeed 90 may be provided with
appropriate discharge chute 94 and receiving chute 96,
respectively mounted on discharge end 80 and infeed end 90
to facilitate the passage of capsules from the first
conveyor 72 to the second conveyor 84. Similarly, the
apparatus shown in FIGURE 2 may be constructed so that
dielectric oven 86 provides part of the support for
primary base 74 at the discharge end 80 o~ first conveyor
72.
In other respects, however, the apparatus illustrated in
FI6URE 2 is genera11y similar in operation, as the fluid
applicator means 98 and capsule washing means 100 are
comparable in construction and operation to the like
structures illustrated in FIGURE 1. The perspective view
of FIGURE 2 permits a better view of the dispenser
manifolds 102 and 104, so that a plurality of respective
dispenser ports 106 and 10~ can be seen. Likewise, air
- 15 -
12~8~
~UIIr~e~ i j5 i~ttc`r illustrated so th~t il-llet plc~nllrll ]1
and exha-lst pl~num 112 are more accurately depicted.
While air tunnel 82 is not shown with appropriate heating
or air recirculating means, it is to be understood that it
can be fitted with these elements in a manner similar to
that illustrated in FIGURE 1, so that the disclosure and
discussion earlier presented herein is applicable hereto.
Referring further to FIGURE 2, the respective conveyors 72
and 84 are shown with schematically illustrated actuating
means or motors 114 and 116 which in accordance with
conventional conveyor construction, would be operatively
connected to the respective conveyors by a drive roller
such as rollers 118 and 120, respectively. In other
respects, the construction of conveyors 72 and 84 is in
accordance with conventional equipment of this type, and
no specific claim is made to the conveyor construction
part from the environment of the present invention.
The operation of the ap~aratus of the present invention
` will now be described with reference to a particular
method for sealing capsules. Thus~ a quantity of capsules
may be fed into the capsule dispenser means or hopper, and
may thereafter be released in a one-capsule layer along
the belt of the conveyor. For most capsule sealing
applications, the belt width may be 18 inches.
The capsules are then fed to the ~luid applicator means
where they are passed through the spray dispenser assembly
and under the dispenser ports. At this point, a quantity
of an adhesion-promoting fluid such methanol, or a mixture
of methanol and carbon tetrachloride, may be applied to
3n the capsules to infiltrate the space between the adjacent
capsule halves~
The capsules pass immediately from the fluid applicator
means to the capsule washing means, where in one
- 16 -
embodiment, a simildr spray dispenser ~ ~lly rele~(s a
quantity of a washing fluid, such as hex2ne, petroleum
ether or carbon tetrachloride. This Fluid is applied -to
remove the excess adhesion-promoting fluid remaining on
the outer surfaces of the capsules, to prevent any
subsequent damage to the capsule walls.
In the alternate embodirnent discussed earlier~ plural
capsule washing means or spray dispenser assemblies may be
provided, in the instance where d first washing fluid is
to be applied to assist in the removal of
adhesion-promoting fluid. For example, when the
adhesion-promoting fluid is a solution of water and
isopropanol, a first washing fluid of pure isopropanol may
be applied to assist in removing the isopropanol solution
from the surfaces of the capsules. Thereafter, a washing
liquid such as carbon-tetrachloride, hexane and petroleum
ether may be sprayed on the capsules to remove any
remaining adhesion-promoting fluid, as well as residual
solvent utilized as the first washing fluid. Similarly,
if the adhesion-promoting fluid comprises a suspension of
gelatin in methanol, one may apply methanol as a first
washin~ fluid, followed by application of a second washing
fluid selected from carbon tetrachloride and the like.
After emerging from the capsule washing means, the
capsules enter the drying tunnél where they are exposed to
a flow of air which may, as illustrated herein, be in
countercurrent relationship to the direction of travel of
the capsules. In a particular embodiment, the drying
tunnel may be 6 feet in length and may utilize an air flow
of ~00 cfm, and a temperature ranging from 90 to 100C.
The residence time of the capsules in the drying tunnel is
usually on the order of 1 minute or less, as this is
sufficient time to successfully evaporate or volatize off
any excess and unwanted ~luids that may be present on the
outer surfaces of the capsules.
~2~
.
Ihe c~ps~lles then travel through the dicle(lric ~nergy
~ealls which, as indicated earlier, may op~ e at an
energy emission leve1 of from 10 to 15 ~, to generate
sufficient heat to achieve the sealing or bonding of the
capsule walls to each other. In this connection, the
adhesion-promoting fluid may be one having a high
dielectric constant, so that -the exposure to dielectric
energy achieves a localized solubilization or solvation of
the adjacent capsule walls, and thereby forms a firm weld
or bond that is both tamper-proof and fluid-tight. In
this connection and as described earlier, the capsules may
be passed through the present apparatus a plurality of
time to achieve complete, fluid~tight bonding of the
capsule walls, in the instance where the capsules contain
various liquids.
After emerging from the dielectric energy means, the
capsules are fed to the discharge end of the conveyor,
where they are deposited in an appropriate collecting
means, such as the receptacle and alternate structures
described earlier. Alternately, in the instance where
residual moisture is believed to remain in the capsules, a
further drying means may be disposed between the
dielectric energy means and the collecting means, so that
the capsules may be subjected to a further drying cycle.
Such drying means may be of thé type illustrated herein,
or may comprise a vacuum drying apparatus7 infrared heat
generating apparatus or other means known for this purpose.
The present invention is intended to embrace all of these
alternate drying means within its scope.
The apparatus described and illustrated in FIGURES 1 and 2
may be further modified in the instance where specific
treatments must be employed. Thus, in the instance of
certain capsules wherein the adhesion-promoting fluid and
the washing fluid tend to discolor or otherwise adulterate
~26~g4
the capsule walls, it may be desirable to dispense the
adhesion-promoting fluid at a temperature which may be
lowered to on the order of -20C. In such instance, the
fluid applicator means may be modified to include a fluid
chilling system such as a refrigeration or heat exchange
coil, to pre-cool the adhesion-promoting fluid to the
desired temperature prior to the application of the fluid
to the capsules. Similarly, and as illustrated, the fluid
applicator means and capsule washing means may utilize
solvent recovery systems, including solvent tanks and
other recirculating means, to conserve the respective
fluids, and to avoid unnecessary release of these fluids
into the surrounding working environment.
From the foregoing, it can be seen that the present
apparatus is of simple constrllction and operation. The
nature of the apparatus and the process that it performs
make it possible to achieve the high volume of capsule
processing indica-ted earlier. Thus, when the conveyor
belt is operated at a speed of from 20 to 80 feet per
minute and the other operating parameters specified above
are observed, it has been found that a wide variety of
capsules may be processed in quantities of up to 1 million
capsules per hour. Naturally, various parameters of
specific capsule formula-tions will vary, and the present
apparatus can be modified accordingly.
It is understood that the invention is not limited to the
illustrations described and shown herein, which are deemed
to be merely illustrative of the best modes of carrying
out the invention, and which are suitable of modification
of form, size, arrangement of parts and details of
operation. The invention rather is intended to encompass
all such modifications which are within the spirit and
scope and defined by the claims.
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