US2492861A - Apparatus and method for manufacturing capsules by upward displacement - Google Patents

Description

Dec, 27, 1949 w. GUNNELL 2,492,861

APPARATUS AND METHOD FOR, MANUFACTURING CAPSULES BY UPWARD DISPLACEMENT Filed May 27, 1946 INVEVTOR. ROBERT w. GUNNELL AIIQRNEL A Patented Dec. 27, 1949 APPARATUS AND METHOD FOR MANUFAC- TUBING CAPSULES PLACEMENT BY UPWARD DIS- Robert W. Gunnell, Detroit, Mich., assignor to Industrial Sound Systems, Inc.,

Cleveland,

Ohio, a corporation of Ohio Application May 27, 1946, Serial No. 672,568

3 Claims. C1. 18-1) This invention relates to the manufacture of capsules and particularly to the formation of a seamless leak-proof coating about a globule of content material such as a medicament, vitamin oil or the like.

Reference is hereby made to my United States Patent No. 2,342,661, dated February 29, 1944. Generally the method of manufacture therein disclosed comprises the introduction of a measured amount of refrigerated content material, which advantageously may be in liquid form into a bath of heated congealable film-forming or coating material having the characteristics of being substantially liquid while hot and a tough solid at room temperatures, one such material being of the group of gelatins. Manifestly, the congealable content material in contact with the surface of the refrigerated content material is sufficiently cooled, thereby to solidify a film or coating about the globule substantially to comprise 'a seamless continuous enclosure or protective coating. Essentially, the time of exposure of the content material to the heated coating material is determinative of the characteristics of the ultimate capsule. Excessive exposure of the coated globule therein eventually results in the equalization of material temperatures whereby the solidified coating may be remelted ultimately to produce a capsule with an insufficient amount of film thereon; and too little exposure invariably results in considerable unevenness and the incomplete coverage of the globule. Subsequently, the coated globule is exposed to a bath of cool conditioning liquid, which hardens the deposited coating sufficiently to enable the capsule to be handled for drying and packaging without damaging or deforming the final product.

It is an advantageous feature of the capsulating process described that substantially the entire manufacture may be automatically induced. For the purpose materials of definite and predetermined specific gravities and solubilities are selected, such that the immiscible content material automatically rises or falls within the coating material depending on whether the specific gravity thereof is less or more respectively than the surrounding liquid. Similarly, the conditioning liquid is selected to be immiscible with the coating liquid and of a specific gravity in relation thereto which will dispose the column on one sideor the other of the coating liquid, such that themoving globule will pass therethrough subs'cqliehtly to the passage through the coating liquid. For example, when the content material has a lesser'spcciflc gravity than the coating and the conditioning liquids, the'globule willrise first through the coating material and then through the column of conditioning material which is selected to be of lesser specific gravity than the coating material thus to b superposed thereon.

It is well understood that from the product viewpoint, it is a desideratum to produce capsules containing a measured amount of content material, so that as inthe case of medicaments or vitamin oils, capsules of substantially equal strength are continuously produced. It is equally well understood from a physico-chemical viewpoint, that substantially equally sizedglobules necessarily be formed. Otherwise the non-uniform flow of the heterogeneous mixturev of globules will prove a detriment to'the continuity of production, in view of Stokes lawsrelating the rate of settling or rise ofa particle in proportion to the square of its radius. There fo iajit is evident that any non-uniform globules formed will greatly vary in the rate of rise, thereby to produce a production process not conducive, to the continuity of fiow necessary for mass production. j

Not infrequently, portions of ejected material break away from the nozzle before the ejection cycle has been completed, thereby to produce. substantially non-uniform globules, and beadlets.

For other reasons having a relationship with the rate of flow, buoyancy effect, means of ejection, or surface tensions, one or a number'of globulesv and beadlets of content material may formfrom one injection cycle thereby to produce variously sized globules which remain in the liquid.col-.

umns for different lengths of time, producing an undesirable product and a'process which necessitates frequent purging substantially to eliminate the beadlets contaminating the various liquid columns.

It is an object of this invention to. provide a new and improved method for introducing a.

measured quantity of content material into superposedlayers of coating and conditioning liquids in a manner which substantially eliminates the formation of undesirable beadlets of the.

content material.

Another object is the production of a device of the type described which is adapted to introduce content materials into acoating liquid in a' manner that encourages the .formation .of individual globules vcontaining the 'measured,

amount of elected content material.

A further bject is to produce an material is retained in the immediate vicinity of the ejection nozzle until the measured amount of content material is ejected, thereby to encourage the formation of a single globule containing all of the material ejected.

A still further object is to provide a downwardly inclined ejection tube whereby the content material must rise'by the nozzle so that all of the measured material will be contained therein.

Other objects and advantages of the invention will hereinafter appear, and for purposes of illustration but not of limitation, embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a front sectional elevatlonal view of the capsulating apparatus provided with an improved ejection nozzle;

Figure 2 is an enlarged detailed view partially in section of the nozzle illustrated in Figure 1;

Figure 3 is a detailed sectional view of the conventional upright nozzle and illustrated the formation of beadlets therefrom;

Figure 4 is a detailed fragmentary view of capsulating apparatus in the region. of the ejection nozzle; and

Figure 5 is a detailed sectional view of another form of eiection nozzle.

The illustrated embodiment of the invention comprises a chamber I having a series of orifices arranged in the bottom thereof. only one orifice H being shown in the illustration for the introduction therethrough of content material conducted to the ejection device I 2 by means of a tubular passage l3 communicating with the material reservoir I4 A part l connects the tube l3 with a cylinder H5 in which a piston l1 and a piston rod l8 are reciprocable to eject a measured amount of content material which automatically flows into the cylinder to fill the space intervening between the piston and the orifice.

It is evident that the controlled stroke of the piston is determinative of the amount of content material which will be forced from the nozzle I9 and into the base of the column 20 of coating material. It is to be understood that other metering means may be provided to regulate the amount of content material ejected. One such means for use in combination with the above described elements ma include a bleed valve to release a measured portion of the content material entrapped by the movement of the piston II beyond the inlet port 15.

The piston and cylinder are enclosed by a housing 2| which is secured, as by brazing. to the bottom of the chamber In in axial alignment with a tubular sleeve 22 that extends upwardly into the column of con ent material. and forms an integral part of the chamber or is secured thereto in a manner which militates against leakage of liquids therethrough. As illustrated in Figures 1, 2 and 4, a nozzle I9 is adapted to have one end 23 securely seated in the vertically disposed sleeve 22 with the outwardly extending portion formed into a curvilinear nose 24, the end portion of which is inclined downwardly to form an angle with the horizontal whereby the rise of the globule of content material ejected therefrom is not impaired by the nozzle, nor such that the globule will be spaced from the nose by the mere fact that arise occurs immediately ,on ejection. A suitable angle has been found to be in the region of 25 with the horizontal. Fire polished glass has been found to be a suitable material for 4 use as the nozzle member, glass being easily formable to the desired shape, impervious to the attack of the heated contacting materials, and presenting less wall friction to the passing content material which may be viscous in the cooled state. However, it is h to be understood that other formable tubular material may be used.

For production purposes, it is desirable to introduce the content material at a reduced temperature substantially in the range of 0-20 F. and for such purposes, cooling jackets or coils 25 are disposed about the cylinder housing 2i, it being understood that additional means for .cooling may be provided including cooling coils ing liquid at reasonable elevated temperatures and solid at ordinary room conditions, being edible, non-toxic, substantially tasteless, and insoluble with the materials to be contained there- 1n.

As previously explained, after the refrigerated globule has acquired a solidified film of coating material, it is necessary to cool and set the capsule so that it may be subsequently handled, dried, and packaged, and for such purpose, a col umn 28 of conditioning material having a lower specific gravity and being immiscible with the coating material, is superposed thereon. The coated capsule C continues to rise therethrough to the surface in view of the fact that the specific gravity of the combined coating film and content material is less than the specific gravity of the conditioning liquid which is continuously cooled to a predetermined temperature range by means of cooling coils 29 wound about the upper portion of the chamber Ill.

The upper surface of the conditioning column 2 8 is level with the lower edge of a downwardly inclined delivery spout or chute 30 comprising a part of the chamber l0 and which is suitable for drawing off excess liquids within the chamber and through which the conditioned capsules C may be delivered from the surface of the condi-- tioning liquid column.

In operation, the ejected refrigerated globule remains in the immediate vicinity of the nose in view of the necessity of first overcoming the downwardly directed directional movement of the globule upon emission by the buoyancy forces which naturally urge the globule in the upward direction. Evidently the time interval required for the deceleration in the one direction and the acceleration in the other, in combination with the movement of the globule ini-,.

tially in the downwardly direction and subsequently in the upwardly direction, causes the globule to remain in the region of the delivery nose a substantially greater time interval than.

would be obtained as from an upwardly disposed nozzle I9 from which the liquid content material is initially forced in an upward direction as illustrated in Figure 3, In the latter method, the

buoyant forces operate to increase the rate ofupward movement of the emitted liquid, thereby-1 to elongate the globule and in combination with.

the surface tension forces, to cause it to break away from the nozzle before all of the content material has been emitted. In this manner one or more globules A and beadlets B are produced from the measured amount of material. It is manifest that the delay of the globule at the nose of the ejection nozzle will be instrumental in the formation of a single globule that contains all of the measured amount of content material, so that detrimental beadlets or variously sized globules will not be formed.

One other modification of ejection device suitable for the purposes described is illustrated in Figure 5, the globule delaying feature residing in an upwardly inclined baifie 3| which is positioned over the vertically disposed nozzle 32 secured to the tubular sleeve 33 by means of a connecting plate 34. The baffle 3| operates to retard the upward movement of the upwardly ejected content material so that the entire measured amount is delivered before the globule is separated from the nozzle a distance suflicient to cause globule separation therefrom. Theoretically, the bafile resists the forces urging the globule in the upward direction, the resultant force operating to move the globule in the inclined direction being substantially less, thereby more slowly to move the content liquid from the vicinity of the nozzle. In addition, the baffle forces a change in the direction of flow as well as presentlng a surface that ofiers substantial resistance to flow, thereby to enhance the desired retention of the globule in the immediate region of the nozzle until all of the measured material has been ejected.

It is manifest that I have produced a novel and new ejection means whereby the ejected content material is caused to remain in the immediate region of the emitting nose enabling the entire amount of content material to be forced therefrom before the globule has broken away from the ejection device, and in this manner to produce globules which are uniform in size, thereby to eliminate the formation of non-uniform globules and beadlets which are undesirable and are a detriment to the production process.

It is to be understood that numerous changes in details of construction and choice of materials may be effected without departing from the spirit of the invention especially as defined in the appended claims.

What I claim is:

1. In a capsule forming apparatus, the combination of a chamber having therein superposed layers of capsule coating liquid and cooling liquid of difierent specific gravities and immiscible with each other, and a nozzle in said chamber disposed at an angle substantially greater than but less than with the direction of natural flow, said nozzles introducing the liquid content material into the coating liquid for passage through said superposed liquid layers.

2. Apparatus for forming capsules as claimed in claim 1, in which the content material is of lesser specific gravity than the coating or cooling liquid thereby naturally to flow upwardly through said superposed columns, said cooling liquid being of lesser specific gravity than the coating liquid thereby to be superposed thereon, and means for refrigerating the upper portion of the cooling liquid column.

3. The method of fabricating capsules which comprises introducing in a downwardly inclined direction thereby to be delayed at the point of introduction into a capsule coating liquid, the content substance at a temperature below the congealing point of the capsule coating liquid so that the content substance will acquire a congealed film of coating material, and causing the coated content substance subsequently to rise out of the coating liquid and into a body of cooling liquid, thereby to harden the film of coating material about the content substance.

ROBERT W. GUN'NELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,275,154 Merrill et al Mar. 3, 1942 2,339,114 Scherer Jan. 11, 1944 2,342,661 Gunnell Feb. 29, 1944 2,428,911 Gunnell Oct. 14, 1947 2,436,439 Lincoln et al. Feb. 24, 1948

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