US2702923A

US2702923A - Method of capsulating

Info

Publication number: US2702923A
Application number: US281739A
Authority: US
Inventors: Neal N Plourde
Original assignee: GUNNELL CAPSULATIONS Inc
Current assignee: GUNNELL CAPSULATIONS Inc
Priority date: 1952-04-11
Filing date: 1952-04-11
Publication date: 1955-03-01
Anticipated expiration: 1972-03-01

Description

March 1955 N. N. PLOURDE 2,702,923

METHOD OF-CAPSULATING Filed April 11, 1952 3 Sheets-Sheet 1 FIG I INVENTOR NEAL .N. PLOURDE I: BY

ATTORNEY March 1, 1955 N. N. PLOURDE METHOD OF CAPSULATING 3 Sheets-Sheet 2 Filed April 11, 1952 FIG 2A INVENTOR f NEAL-N. PLO RD MW ATTOR .\'EY

March 1955 N. N. PLOURDE METHOD OF CAPSULATING 3 Sheets-Sheet 3 Filed April 11, 1952 1.\ ENTUR NEAL N. PLOURDE,

A T71 )RNEY United States Patent- METHOD OF CAPSULATING Neal N. Plourde, Detroit, Mich., assignor to Gunnell Capsulations, Inc., Van Dyke, Mich., a corporation of Michigan Application April 11, 1952, Serial No. 281,739

7 Claims. (Cl. 18-48) This invention relates to improving the character of capsule coatings or shells.

Capsule shells of the character here involved are applied in liquid or fluid condition to a measured quantity of capsule fill or content material, and thereafter treated to harden and finish the coating. According to the present invention the capsule with its fluid or semi-fluid coating or shell is rotated in the treating medium to maintain the shell of uniform thickness until it has hardened sufiiciently to lose its capacity to flow. The capsule shell while in a soft but non-fluid condition may also be formed into non-spherical shape. I

The further nature and details of the invention Will readily appear from the following description of illustrative embodiments of the invention shown in the accompanying drawings.

In said drawings:

Fig. 1 is a sectional elevation of a treating receptacle equipped with capsule rotating means in the form of a pair of belts;

Fig. 1A is a sectional View taken along the line A--A 1n Fi 1;

l ig. 2 is a view similar to Fig. 1 wherein a single belt and a stationary surface cooperate to rotate the capsule;

Fig. 2A is a sectional view taken along the line A-A in Fi 2' l ig. 3 is a view similar to Fig. 1 showing opposed belts arranged both to rotate the capsule and to form 1t1nto nonspherical shape;

Fig. 4 is a view similar to Fig. 2 showing the belt arranged to travel in a horizontal direction; and

Fig. 5 is a view similar to Fig. 1 wherein a series of rollers instead of belts are employed to rotate the capsules.

Seamless capsules may be formed, as in Gunnell Patent 2,342,661, by applying a coating or covering fluid form around a quantity of capsule content material, and then hardening or setting the coating. In the case of thermoplastic shell materials, such as gelatin, thrs is done initially by cooling the shell in a cooled liquid bath through which the capsule is passed. The fluid shell material may be initially applied in various ways such as by passing a globule of content material through a bath of gelatin in liquid condition and collecting a seamless layer of shell material directly on the globule, as in said Gunnell patent. In another method shown in Mabbs Patent 2,379,816, a measured quantity of content material is extruded inside a tubular stream of shell material. Globules of the composite material are dropped into a cooling bath to harden the shell. The surface tension of the content and shell materials causes the capsules to assume spherical shapes. The invention is not limited to any particular way of initially applying a fluid coating to the content material.

Since the coating or shell, however applied, remains fluid or semi-fluid for an appreciable time after it has been applied to the contentmaterial and has assumed a spherical shape, the forces acting on its cause the shell to thin off at the top of the capsule and collect adjacent the bottom of the capsule as it passes through the cooling or setting bath. This may be caused by gravity, unequal cooling of the shell, etc. Capsules with a coating of nonuniform thickness will often be defective (e. g., the thin portion of the shell is weak and often breaks), but in any case they are not marketable.

According to the present invention the shell material is prevented from segregating and is maintained uniformly distributed over the content material by rotating the capsule until the shell material has hardened to non-fluid condition. Various means for rotating the capsule may be employed. These are not limited to the illustrative means. According to the means here illustrated, substantially as soon as the capsule enters the cooling and hardening bath it is placed in control of a rotating device and is rotated thereby about a generally horizontal axis at a rate sulficient to prevent segregation of the shell material. One form of rotating device is a belt 10 moving in the direction of travel of the capsule which transmits to the capsule as it is suspended in the hardening bath suflicient force to rotate it. The layer of liquid dragged along by the moving belt may exert sufficient frictional force to rotate the capsule without actual contact of the capsule with the belt itself. Various means may be employed to maintain an operative contact with the capsule. In Fig. 1, for example, another oppositely traveling belt is placed opposite the main belt 10 and spaced therefrom a distance sufficient to receive the capsule between the adjacent runs of the belts. Substantial frictional contact with the capsule is not necessary because the belts in moving through the cooling bath drag a film of liquid with them which film is suflicient to cause rotation of the capsule. Where, as in the present case, the capsule rises through the hardening bath, the upwardly traveling run of the belt, in this case belt iii, preferably travels slightly faster than the downward travel of the opposite belt 11, thereby to assist in moving the capsule upwardly through the bath. For other directions of capsule travel, i. 'e., down, horizontally, etc., the belt moving in the direction of capsule travel should have the higher rate of speed. Preferably the capsule is placed between the belts to be rotated as soon as practicable after it enters the cooling bath.

A jet of liquid or circlulation of the liquid may also be employed to cause the capsule to rotate through the apparatus.

The rate of rotation of the capsule need not be sufiicient to create any substantial centrifugal forces since the shell material is maintained at a uniform thickness simply by continuously changing the position of the capsule so as to counteract any tendency of the shell material to distribute itself non-uniformly.

The belts may be formed of a plurality of metal links which present a smooth surface to the capsules or they may be made of flexible metal or fabric. Preferably the belts are supported in such way that their spacing may be adjusted and their rate of speed regulated. The length of run of the belts should depend somewhat on the rate of travel of the capsule through the bath. Generally such length varies from 8 to 16 inches. For travel of the capsule through a horizontal bath, the belts would be appropriately re-arranged to follow the direction of travel of the capsule.

Fig. 1 illustrates details of one illustrative adjusting means. The several pairs of belt pulleys 12 and .13 are supported on vertical members 14 which are in turn carried on transverse members 15 extending across the receptacle 16 containing the bath of cooling or hardening liquid. The belt runs are laterally spaced or adjusted, in this case, by means of slots 17 in the plate members 14 through which supporting screws or bolts connecting the same to the transverse members 15, pass. The belt pulleys l2 and 13 are rotated in the same direction (thereby causing the adjacent runs of belts 10 and 11 to travel in opposite directions) by shaft 18 through flexible driving elements such as chains and sprockets. The driving means here represented at 19 is preferably capable of variation in speed to adjust belt speeds.

Guide means, here shown in the form of rods 20 adjacent the edges of the belts, prevent lateral escape of the capsules.

In cases of horizontal capsule travel the active run of the belt may be very slightly above the liquid of the bath but having contacted therewith initially to draw up a meniscus of liquid at both edges of thebelt. This acts as guide means to prevent the capsule from moving laterally out of the path of the belt. Fig. 4 illustrates one arrangement for horizontal travel, but it will be understood that with obvious rearrangement, the constructions shown in the other figures may be employed for horizontal capsule travel.

After the shell material has hardened sufiiciently to render it non-fluid, the capsule in its still plastic condition may then be processed to non-spherical form. This may be accomplished with the devices shown in Fig. l by causing the belts and 11 to converge slightly to exert compression on the capsules and elongate them in the direc tion of their axes into cylindrical or oblate spheroid form. For this purpose the entrance ends of the belts are spaced apart by the diameter of the capsule plus about to ,4 inch and the exit ends are brought together so as to be spaced only about of the initial diameter of the capsule. The capsule remains under the control of the belts until it is hardened sufficiently to maintain its elongated shape.

In cases where the capsule travels downwardly through hardening bath, the belts are advantageously adjusted for entry of the capsule at the top instead of the bottom. In such case their directions of travel are reversed and their upper ends are spaced to receive the capsule, such spacing being approximately the diameter of the capsule plus 6 to 4 inch, depending upon the action on the capsule desired.

In Fig. 2 is illustrated a simple form of rotating device comprising a single belt 21 located opposite a fixed or stationary surface 22. In the case of upwardly traveling capsules the inner or active run of the belt travels upwardly and rotates the capsules over the fixed surface 22. Guide rods 23 prevent lateral escape of capsules. The thickness of the channel through which the capsules pass may be adjusted by moving the fixed surface 22 either toward or away from the belt. Slots 24 are provided for this purpose. By tapering the thickness of the passage the capsules may be pressed after the shell material has as sumed a non-fluid state, to elongate the capsule.

Preferably guide members, such as the sheet metal guides 25 and 26 in Figs. 1 and 2 respectively are located at the entrance ends of the belts to direct the capsules from their points of introduction into the bath into operative relation with the belts. As here shown, such guides are carried at the ends of guide rods 20.

In Fig. 3 a plurality of belts are shown which permit a greater flexibility in the treatment given the capsule. The main belt 30 has associated with it a lower belt 31 and an independent upper belt 32 capable of independent spacing and direction of travel. The belts are here shown arranged for upward travel of the capsule.

Belts

30 and 31 are adjusted as in the case of the belts of Fig. l to rotate the capsule and move it upwardly until the shell material is no longer fluid. Thereafter the capsule travels into the control of

belts

30 and 32 which are more closely spaced to exert compression on the capsule until it is hardened. If the adjacent runs of the belts travel in opposite directions the capsule will be rolled and compressed into an elongated cylindrical form as heretofore explained. If the adjacent runs of the

belts

30 and 32 travel in the same direction, the capsule may be compressed into a flat lozenge or tablet shape. A deflector guard 33 is located between the

belts

31 and 32 to guide the capsules from one belt to the next to prevent their escape between the belts.

The aforesaid belts may advantageously be supported and driven in a manner similar to that illustrated in Fig. 1.

In Fig. 5 a different form of rotating means is shown comprising a series of pairs of rolls whose adjacent surfaces travel in opposite directions and cause the capsule to rotate as aforesaid. The rolls 41 of one series may advantageously travel at a slightly higher speed than those of the other series 42 to assist in moving the capsules in the desired direction of travel, i. e., in this case, upwardly. Deflectors 43 are located between the rolls to prevent escape of capsules. Suitable guide means prevent escape of capsules.

It is clear from the foregoing that various means may be employed to rotate and later compress the capsules if it be desired to give them non-spherical shape.

Obviously the invention is not limited to the details of the illustrative process, since these may be variously modified. Moreover, it is not indispensable that all features of the invention be used conjointly, since various features may be used to advantage in different combinations and sub-combinations.

Having described my invention, I claim:

1. In the method of making capsules in which the con tent material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath and rotating the capsule while in the bath until the coating is in non-fluid condition by directing said capsules into close proximity with the surface of a rotating member in said bath.

2. In the method of making capsules in which the content material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath and rotating the capsule while in the bath to prevent segregation of the coating and maintaining a uniform thickness of the coating until the latter has hardened to non-fluid condition by bringing said capsules into rolling contact with the surface of a rotating member in said bath.

3. In the method of making capsules in which the content material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath and rotating the capsule while in the bath until the coating is in non-fluid condition, and then before the coating has hardened but after it has lost its fluidity, shaping the capsule into non-spherical form and maintaining such form until the coating has hardened sufficiently to maintain such non-spherical form.

4. In the method of making capsules in which the content material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated in spherical form into a liquid coating hardening bath and rotating the capsule while in the bath until the coating is in non-fluid flexible condition, and then shaping the capsule into non-spherical form and maintaining such form until the coating has hardened to self-sustaining condition.

5. In the method of making capsules in which the content material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath, passing the capsule through the bath and simultaneously rotating it until the coating is in non-fluid condition by directing the capsules between a pair of surfaces in said bath which are spaced apart generally to correspond with the diameter of the capsules and at least one of said surfaces being caused to rotate.

6. In the method of making capsules in which the content material is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath, causing said capsules to travel between a pair of closely spaced belts in said bath which are caused to travel in opposite directions, and causing said belts to rotate said capsules.

7. In the method of making capsules in which the content rnaterial is covered with a coating material in fluid condition, the steps of introducing the capsule thus coated into a liquid coating hardening bath, directing a tangential force against at least one side of the capsule while in the bath and before the coating has become non-fluid to cause the capsule to rotate and continuing the application of said tangential force to said capsule until the coating is in a non-fluid condition.

References Cited in the file of this patent UNITED STATES PATENTS 2,332,671 Scherer Oct. 26, 1943 2,342,661 Gunnell Feb. 29, 1944 2,531,986 Pile et a1. Nov. 28, 1950