US2471358A - Capsulating method and apparatus - Google Patents

Description

May 24, 1949. v. v. sTEPHx-:NSON 2,47L358 CAPSULATING METHOD AND APPARATUS Filed Nov. 22, 1946 2 She'ets-SheeIl 1 IIIIII I I I I I IIIIII III 24, 1949. v. v. sTEPHENsoN 2471358 CAPSULATING METHOD AND APPARATUS Filed Nov. 22, 1948 2 Sheets-Sheet 2 Patented May 24, 1949 UNITED STATES ATENT OFFICE 2,471,858 CAPSULATIN G METHOD AND ,APPARTUS Vernon V. Stephenson, Seattle, Wash.

Application November 22, 1946, Serial No. 711,702

(cl. 18-1 I 6 Ciaims.

This invention relates to method and apparatus for the production of seamless capsules and has as its main object the improvement of such` capsules ,by` the provision of a covering or skin of improved character 'as to strength and uniformity.

,Capsules of the seamless type have heretofore been produced by injecting drops of liquid content substance, such as `fish oil, into a body of liquid capsulating material, ordinarily gelatin,

Vthroughzwhich the drops of content substance Will` rise while collecting a coating of the content substance. Superposed on the capsulating material isv ,abody of liquid which is hardening as to`- the` capsulating, material and through which the pellet will rise.` Heretofore the'supernatant hardeningliquid'has ordinarily been carbon tetrachloride-with added 'materialrfor the suitable adjustment of thespecific gravity. A sharp interface exists between the carbon tetrachloride and the capsulating material and the nascent capsule is frequently vinjured or ruptured as it breaks through this-interface. In accordance with the present invention cooled water is used as the hardening agent with greatly improved results. There is a short zone of intermergence of the two liquid bodiesl and this zone, as opposed to a sharp interface, is readily penetrated by the soft skinned .capsule so that deformation or -rupturing thereof is substantially eliminated. In -view of the rather acrid nature of carbon tetrachloride, water isa much pl-easanter agent to work with and, of course, involves practically no cost. i

`In the'use of heat-liquefied gelatin, the procedure isiextremely critical since the gelatin deteriorates when heated to the required capsulating temperaturefor any extended period. If the gelatin is subjected to heat for any substantial length of time,it provides a weak covering very apt to beruptured in passing the interface, where one exists, or later on in handling. Heretofore, the gelatin has been fed from a heated reservoir, and while it has been proposed to heat the gelatin in the reservoir only to .a degree to render it able to fiowto the capsulating apparatus where its temperature is raised to the necessary degree, this nevertheless kept thegelatinv at a relatively high temperature for a substantial period. In accordancev with another phase` of the present invention,` this difi'icultyV isV largely overcome by injectingthe gelatin into'the capsulating chamber from a mass which is in cold plastic form, liquef'ying heat being-applied substantially only to thegelatin-in'the receptacle; f I

Another diificultyheretofore encountered has been in the injection of the content substance into the capsulating bath. There .has not been a sharp cut-off behind the injected drop and the emergent dropv has had a tail disappearing more or less due to surface .tensionas the drop rises in the capsulating liquidvbut interfe'ring with the rapid gathering of the intended spherical covering. In accordance with another phase of the presentinvention, improved injecting-means are provided wherebyV a sharp cut-off is provided Abehind each drop so that`it` almost instantaneously assumes a substantially'spherical form, thus facilitating the rapid formationaround it of a substantially spherical covering 'of theocapsulating material. a a I Illustrative apparatus accordance with the invention is shown 'in the accompanying drawingsinwhich Figure 1 shows somewhat diagrammatically and with parts; in Vertical sectiona, completeinstallation, i

Figur-e 2is a section on line 2 2 of` Figure 1,

Figure 3 isan enlargement vof the lower portion of Figure 1 showing, certaincontrol apparatus in Vertical section, and

Figure 4 is a `wiringdiagram, for theV control apparatus. i i I v A base plate Ill has formed in its top surface a cavity I which is cylindrical on a `Vertical axis and receives and has sealed therein the Vlower end of a Vertical cylindrical tube` l2 of glass, or other suitable. material, in the lower portion of which is to be maintained a bodyof liquid capsulating material. Alvertical cylindrical tube [3 extends into` a bore in the ,bottom of the base plate coaxially with the. cylinder |2 and terminates in a coaxial nozzle portion M sealed in a counter-bore and ,projectingintothe cylinder |2. The extremityiof the nozzle has an inturned fiange l5 defining an opening |6 coaxial with cylinder IZ, the inner surface ,ofthe fiange constituting a valve vseat.` Slidable in .the upper portion of the tube |3 is a plunger I] whichincludes a reduced portion I!!l received with fiow clearance in the nozzle portion M 4and terminating in a short Acentral stud I 9 receivable lwith clearance` in the opening `16.,.P1unger I 'iconstitutes a valve body whose upper end cooperates with the seat providedbythe fiang |5. The lower part of the plunger has an'axial bore 20 branched laterally at its upper end to the outer surface of the plunger.

here shown, the tube 13 comprises sections. threaded-together at 2| and providing a` shoulderZZ serving as. an abutment for one end of a compression spring 23 whose other end bears against the plunger to yieldingly retain the valve means in closed relation.

At its lower end, tube |3 is fianged outwardly to provide a cap |3' into which is threaded a cylinder 24 which has a bottom wall 25. Slidable in the cylinder 24 is a power piston 26 which is formed as part of a pump piston A2`| working in the lower portiony 'of'tube 13. compression spring 2B normally holds the piston against an adjustable stop 29 constituted by a screw threaded in the wall 25. Referencenumeral 30 designates a stop collar surrounding the stem 2`| and limiting the upward movement of the piston.

In Figure 1, reference numeral`3| designates a tank containing a liquid content substance and reference numeral 32 designates a pipe extending from tank 3| and lthrough a check valve 33 into .tube `|3 above listem'v 2f|y as most clearly shown in Figure 3. The check'yalveihcludes a ball 34 andva compression "spring "35, N h

Reference -numeral .36ides'ignates a l`rotary valve includinga casing-ttl anda cylindrical'plugil, the latter being'provided)withy adiametrical bore 39. The casi'ngi3'l`is provided a radial inlet in connection 'with' asourceflFigure 1, of' com- 'pressed air throughazpipe' 4| and has a radial exhaust 'opening'j in |onnectionfwith' an exhaust pipe' 42. Interiorly 'itheiilcasingfjsfeat isarcuately relieved at"43,IFig'ure fad sllprovidedfwith a `radial opening midwayjbetweenthe'ends of the recess and in' co'r'i;i'erti on`,'v`v'ith a'pipe v44, "Ir'he latter extends'to'cylinder' 241`1b'e`neath piston 26 and is provided'iwith*a'resti'ictedf'orifice 'fitting or choke; pipe 46 leadsfrom pipef44 in advance of 'fitting" '45` `to^fabellows` 41 which includes a top plate*l 48 y'('z'a'rryingA aiblock of *insulation49 cooperable with the lower` spring arm 50 of a'no'rmallyiopen' switchflfgl'whih includes an armV 52' en'g'ag'eame' `by la'r'mL su i when 'the' benws is expanded from, normally collapsedl condition.

The tube |3., .oriatjleast itslup'per'portionQis of non-ma'tgne'tic'I materialfand'is Tsurrounded by a solenoid coil 53. Pl'unger'- |`|,"`whi`ch" is magnetic, serves as an armatureffor'icoil* 53,the'lar'rangement 'being 'such ;thatwlien' 'the 'coil is energized the plunger is retracted so thatflow can, occur through`v the 'bor L'" around 4' valve' 'portion l8,

ductor 54,'is shown* `asfbeifr'igf in connection with one's'ide of coil` 5,3'thr ughf; a 'wire'55and the other 'side of fthe coil is fin connection with switch arm 52 through'fa' cimluctor` tt,l jThe otherjline conductor" 51' isin `lcanectiqn x'withz the switch arm 50 and;cofiseduentlyjfwhlen theiswitch is closed, coil 53 will be energied.

In` Figure 1,) the valve plug" 38 is 'indicated as beingdriven byaf:rn'otof'58' through' a speed' reducer59 andin Figure' 3.y ljtheidir'ection'oi rotation of the plug 'is'in'dicatdpas icl'o'ckwise. With the plug lin the Vpositionshown,z 'air 'under 'pressure is'being suppliedfrom'the `s`ource`4|l` to the ca'sing rece`ss '43 l and' thhceto pipe 44. 'The bellows' is iminedia'tely ep'andedclosing switch 5|, as shownyand; "thusi'energizing' coil '1 53 "so that plunger is retracted' and the' valve imemb'er IB is unseated,=as'fs l'iown.4 Due' to'the lag caused by the choke ;45, this 'energization occurs sughtiy priorfl'tdthe ;limited Lpward ,movement of 'the pump piston and'when'this' movement occurs, a drop 1 of fcntent" sub'stancej 'tube l 3 "be- I r h isfforc'd through oriflce IB, the size 'of 'the' dropfbeing determined'by the length of the'fpis'tnstroke' 'as c'ontrolled'by the abutment 29. The operated relation of the parts is maintained for the instant required for the end of the plug passage 39 to pass from the end of recess 43 into register with the exhaust pipe 42 and, at that point, the opposite end of the plug passage has reached the opposite end of the recess 43 so that the system is exhausted. The bellows collapses, spring 23 returns plunger ll, spring 38 returns piston 26, and tube |3 is replenished by content substance drawn through the check valve 33 as the piston descends, spring :35 being substantially weaker than spring 23. When coil 53 was de-energized by the opening of switch 5|, spring 23 snapped plunger to seated position, imparting a substantial jar to the nozzle and thus sharply breaking the drop loose as assisted by the entry of stud |9 into orifice |6. The released drop is in effect, shot upwardly, but without disruptive result, into the body of capsulating material in the lower part of cylinder |2 and quickly assumes a 'substantially spherical form. i

Projecting through a r'adial'opening adjacent the lower end of cylinder |2 below the level of capsulating material desired to be maintained in the container defined by the cylinder in 'conjunction with the'base plate, is :the tip end of a nozzle 60. The extremity'of the nozzle tip is closed and between it' and the wall of the cylinder the tip is provided with peripheral openings just beyond a seat which is provided for a spring pressed ball 6|. The outerend of the nozzle is threaded in an opening in a'housing 62 in which is reciprocable a nut 63 having a cylindrical' extention 64 constituti'ng a'piston working in a cylindricall portion of lthe nozzle, the nut being 'held against rotation by rmeans' of a' finger 65 which 'is received' in al longitudinally extending groove 66 lin a wall 'of the hous'ing. The nut is engaged by a screw 61 journalled in an end wall of the housing and having fixed thereto outwardly of the wall a ratchet wheel 68v with which is co- 'operable a pawl 59,' Figure 4, pivoted to the armature ll)v of a sol'enoid'll, the ends of the solenoid' coil being `in |connection, respe'ctively, with lead 54 through a'wire 12 and'with switch arm 52 through a wire' 13.

With the piston 64 retracted, a stick of gelatin in plastic condition can be introduced into the nozzle througha door 14, Figure 3, whichA may then be latched closed ;in any suitable manner. Wheel 68` may now befmanually turned to advance the piston so as to push the gelatin mass up tothe check 6|, Thereupon, the apparatus being set in operation, solenoid f|| vwill be energized each time switch 5| is closed so that wheel 68 is stepped around and gelatin is intermittently extruded past the' check into the container. When 'the supply in the nozzleis exhausted, the piston 64 is again retracted'and aA new stick of plastic gelatin inserted. The check4 6| prevents withdrawal from vthe container' when the piston is `retracted.

The lower part of cylinder |2 lis heated, with the heat localiz'ed as Zfar as possible in any suitable manner. Induction heating may be utilized as here indicated. In1 Figure 2, a coil wrapped around the lower portion of the cylinder has its ends 15 and 16, Figure 1, 'in connection with a source of high frequency 'power and a second coil has its ends and '|8 in connection with a high frequency load tuner. Preferably, a gelatin is used having a relatively high gel point, lfor example F. since suchv a gelatin has superior strength. The gelatin in the 'container should |be in free flowing condition such as is produced at a temperaturafor example, ofA 1,15, and may have a specific gravity of the order of 1.090.

Since the nozzle 80 projects-into the heated container, the gelatin in its extremity Will be relatively fluid but to prevent the heating of the plastic gelatin in the outer portion of the nozzle, the latter may be jacketed as indicated at 19, Figures 2 and 3 for the circulation of a cooling fluid. The point is that the plastic gelatin should be maintained in that condition as nearly as possible up to the time of its discharge into the container. i

Furthermore, the volume of liquefied gelatin in the container should be maintained at a minimum. In general, the cross-sectional area of the gelatin body should be no greater than to enable the nascent capsules to rise without bumping the cylinder wall and without creating too much turbulence, and the depth of the gelatin body should be substantially only that necessary to permit the desired accretion of capsulating material by the injected drops. In this manner, no gelatin will remain in the heated bath long enough to materially deteriorate. The gelatin in the bath is consumed at a rate depending on the size and frequency of the injected drops of content substance and the delivery rate of the gelatin extrusion apparatus is such as to maintain a substantially Constant level of gelatin in the container, this level being generally indicated at L in Figure 1. Different pawl and ratchet drives may be used to obtain different rates of feed.

The upper end of cylinder |2 projects into and is sealed against the rabbeted lower margin of a circular opening 88 formed in a circular plate 8|, the interior of the cylinder being fiush with the opening. Threaded on the plate is a ring 82 having an annular groove receiving a gasket 83 which makes a peripheral seal with a cylinder 84 which is supported on the plate. Supported on the plate within and in spaced relation to the cylinder 84, is a cylinder or curtain 85 which is coaxial With the opening 80. The upper ends of the two cylinders terminate at the same height and the annular space between them is closed at the top by a sealing member 86.

The lower portion of cylinder 85 is provided with a number of symmetrically disposed up- Wardly and inwardly directed openings 81. Reference numeral 88 designates an inlet pipe for the hardening fiuid, which in this instance is water at the required temperature, the pipe being lead into the upper end of cylinder 84 to the annular space between the two cylinders.

supported on the upper end of the cylinders is a pan 89 having a bottom opening 90 registering with the inner wall of cylinder 85. At one side the pan has a Weir 8| below which is an inclined screen 92 whose lower end is above a conveyor 93.

Water introduced through pipe 88 fiows down the annular space and into cylinder 85 in an upward direction and fills the container means from the gelatin level L up to the overflow. The flow into cylinder 85 is even, due to the symmetrical disposition of openings 81, so that turbulence immediately above the gelatin bath is minimized. The upwardly convergent currents tend to hold the rising capsules to the center line of the container. The temperature of the water may be maintained at, for example, from 60 to 75 F. By using a suitable anti-freeze, the temperature of the water can be maintained below 32 F. if desired, but the higher temperature range mentioned is ordinarily satisfactory.. .The water directly adjacent the gelatin bath of vcourse graduates in temperature from'that of. the .bath to that of the main body of water.. .There is an appreciable intermergence of the water `and liquid gelatin with the beneficial effect,` mentioned at the outset, of providing an easypassage of the soft skinned capsule from the gelatin body to the water body. However, there. is no general. dilution of the gelatin body by the water. In rising through the water column, whichis also rising, the gelatin coating of the `pellets hardens and the pellets pass over the weir 8| and then roll down screen 92 onto the conveyor 83 the water falling through the screen. The conveyor delivers the pellets for further processing or packaging.

, The content material may be medicinal oils such as Vitamin-rich fish oils, for instance a soup-fin shark oil having a specific gravity of 0.920 at F. As above mentioned, the gelatin may have a specific gravity of 1.090, butsince the content material constitutes the dominant part of the coated pellets, the specific gravity of the latter will sill be less than that of pure water so that the pellets will readily rise through Vthe latter.

I have shown the invention in one practical embodiment by way of example and it will be understood that other forms and arrangements of parts are possible and are contemplated under the invention as defined in the following claims.

I claim:

1. Capsulating apparatus comprisng receptacle means containing a body of liquid capsulating material, a conduit in connection with the bottom part of the receptacle means for the supply thereto of liquid content substance, valve means comprising a valve seat in the conduit adjacent said receptacle means and a spring loaded valve body cooperating with said seat and normally preventing discharge from said conduit, said valve body being magnetic, a coil with respect to which said valve body is arranged as an armature, an energizing circuit for said coil and a normally open switch therein, a source of content substance, a pump having its intake side in connection with said source and its output side in connection with said conduit, expansible Chamber means associated with said pump for the operation thereof, expansible Chamber means for operating said switch, a source of air under pressure, a control valve in connection with said air source and both of said expansible Chamber means, means for Operating said control valve for the intermittent supply of air to both of said expansible Chamber means, and choke means between said control valve and the expansible chamber Operating means for the pump.

2. In capsulating apparatus comprising a container for a liquid capsulating material and a nozzle associated with the container for the intermittent injection of content material into the container, the combination of means for jarring the nozzle at each injection to detach a drop of the content material therefrom.

3. In eapsulating apparatus comprising a container for a liquid capsulating material and a.: nozzle associated with the container for the inter-. mittent injection of content material into the container, the combination of a plunger slidable in said nozzle, an abutment for said plunger in the extremity of the nozzle, spring means urging said plunger against the abutment, and means for retracting said plunger at each injection and 're'leasing it for return by said spring means *whereby to jar the nozzle'to detach a drop of the vcontent material therefrom.

4.'In` capsulating apparatus comprising a contain'erv for 'a liquid capsulating material and a nozzle associated with the container for the inter- -mittentinjection of content material into the `'(onta'iner, the combination of a valve body mov- 'able in the n'ozzle, a seat at the tip of the lnozzle 'for 'said valve body, spring means'urging said -valve body'against said seat, andlmeans for retracting said valve body at each injection and lreleas'ing' it for return' by said spring VVmeans "`Wie1"e'by to 'jar the nozzle to detach a drop'of :the

cntent'material therefrom.

v'5. In the manufacture of seamless capsules by intermittently injecting liquid capsulating' sub- 'stance lfrom a nozzle intoa bath'of' 'liquid capffsulating'f'material Whereby to form "'p'ellets com- 'prsing al core of the content substance and a soft coating'of :the capsulating material, and 'then "hardening`- the c'oating, the method' which com- `1"ri'ses'jarring thenozzle at each'injecting'action tofac'ilitate theseparation of a drop from' the "nozzle.

` 6. Capsulating anparatus comprsing container means'for av capsulating material, a vertically elongat'ed'tank above said container means in communication therewith and of larger horizontal 'section than the same, a curtain in said tank defining an annular chamber therewith spaced outwardly of said container means, an inlet at the upper end of said Chamber for a liquid which is hardning as to the-capsulating material, pas- Sage means between the lower part of said chamber and the interior of said curtain, an overflow at the top of said curtain, and-means for injecting drops of content substance into the bottom of said container means, said passage means comprising a number of inwardly and upwardly directed openings injsaid curtain.

VERNON V. STEPHENSO-N.

` REFERENCES' CITED *The 'following' references are of record in the file of' this" patent:

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