US2674073A - Relieved nonskid seal roll and method of use - Google Patents

Description

April 6, 1954 A. s. TAYLOR ETAL RELIEVED NONSKID SEAL ROLL AND METHOD OF USE Filed Dec. 5, 1950 2 Sheets-Sheet l E Y m P INVENTORS Fxm/wr it 6771?, Apr/7a,? a. 74y: 0A

ATTORNEY April 6, 1954 A. s. TAYLOR ET AL 2,674,073 RELIEVED NONSKID SEAL ROLL AND METHOD OF USE 2 Sheets-Sheet 2 Filed Dec. {5, 1950 I l 4 I I 1 I I I I m; nh l. Z

v 'Hm' b INVENTORS ATTORNEY Patented Apr. 6, 1954 RELIEVED NONSKID SEAL ROLL AND METHOD OF USE Arthur Sinclair Taylor, Spring Valley, and Frank Edwin Stirn, Pearl River, N. Y., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine Application December 5, 1950, Serial No. 199,244

9 Claims. I

This invention relates to improvements in a method and mechanism for forming and filling capsules from soft gelatin strip which capsules may be filled with any desired material, and relates particularly to the use of a seal roll which has depressions therein of a size sufiicient to permit the expansion of a filled capsule into the depression so that as the seal roll compresses "through the gelatin layers forming the capsule, the displaced volume can expand into the relieved depressions on the seal roll. and also to a releasing agent to prevent the adhesion of the gelatin strip.

An additional advantage is that the gelatin shells in the cavity die roll may be completely filled, thereby permitting the use of a doctor blade with either a liquid or a powder. It permits filling the capsule shells level full before placing the cover thereon.

Another object of our invention is to provide a method of varying the size of capsules which may be produced from a single cavity die roll by changing the seal roll only.

It is an additional advantage of our invention that uniform capsules may be obtained without metering the individual charges.

It is yet another object of our invention to provide a resilient insert to form a portion of the areas of the depressions whereby variations in the capsule contents compress this resilient por tion without any tendency to be forced out of the die system.

It is yet another object of our invention to permit the depressions to be subjected to a vacuum pulling the gelatin into the depression and thereby assist in preventing the skidding of the gelatin on the seal roll, and aid in heat transfer.

It is a further object of our invention to provide a releasing agent for the seal roll which prevents the gelatin film from sticking to the seal roll.

It is yet another advantage of our invention that great precision in the timing of the die roll and the seal roll is not required. It permits the use of an inexpensive seal roll with an easily formed depressed area rather than an expensive built-up or engraved die roll, and obviates the necessity for precise mating axially and angularly of the seal roll and the die roll.

In the past it has been the custom to use cooperating die members such as is shown by Cowley. U. S. Patent 2,387,747. With such a type of construction, accurately mated cutting out rims were required as, for example, shown by his Figure 2. With capsules of the size used for medicinal purposes, a variation of a few thousandths of an inch from the proper position would give a defective seal. By using a cutting out rim against a cylindrical surface of the seal roll, it is possible to use a much less precise structure. The depressions in our seal roll can be matched against the die roll so that a 32nd of an inch variation or more in any direction from the center position gives perfect capsules. Such precision can be attained by the use of the naked eye, and rapidly. The prior type of device required accurate measurements with micrometers or optical devices to insure a proper seal.

Our device may be used in connection with the general type of capsuling machine shown by Cowley or that disclosed in our copending applications, Serial No. 164,426 filed May 26, 1950 and Serial No. 174,748 filed July 19, 1950.

When a fiat seal roll is used against a cavity die roll, the two gelatin strips are compressed down into the cavity and there must be sufficient space left in the cavity for this compression, and it is necessary that this compression take place evenly so that trapped material does not distort the capsule.

By the use of the present invention, there is provided a seal roll which has a depression opposite each capsule forming cavity so that the capsule shell may be filled level full. This permits the use of a doctor blade with free flowing powders and permits overflow filling with a liquid. As the upper layer of gelatin is placed over the capsule shell, it closes the shell without trapping air. As the seal roll and die roll press the two gelatin strips together so that the upstanding edges on the cavity roll out into the two gelatin sheets and simultaneously seals them, the displaced volume of material can shift into a depression in the seal roll, thereby permittingya perfect seal of the cut out portions of the gelatin strips.

By making the depression area somewhat smaller than the size of the die cavity rim, any variations in the gears, or in machining, or in adjustment, is self-compensating. When the capsule is released from the cavity, it will assume a symmetrical configuration and any distortion in the symmetry of the mating of the die members does not afiect the symmetry of the finished product.

To prevent the gelatin strip from slipping on the seal roll, it is necessary to operate without a lubricant on the seal roll. An oil such as has been previously used to prevent sticking will allow the gelatin film to slide and give an uneven 3 seal. This is particularly noticeable with fiat oval capsules in which there is a straight cylindrical central portion between hemispherical ends.

At the same time, the seal roll must be treated so that the gelatin film will not stick to it. If the seal roll is warm, as is preferred for rapid operation, there is an even greater tendency for the gelatin strip to melt or stick on to the seal roll.

We have now found that certain materials which are volatile, non-tacky, non-Water soluble and which have a comparatively low viscosity and high adhesivity for the seal roll, are effective as releasing agents. A deodorized kerosene is particularly advantageous for this purpose. The commercially available material sold as Deobase by L. Sonneborn Sons, Inc., New York, is in this class. This material is a petroleum distillate, refined to freedom from kerosene odor,

with a specific gravity of approximately 0.775; Saybolt viscosity at 100 F. of 30-35; an open cup flash point of around 170-l80 F.; an initial boiling point between 3'70 and 396 F. and an end point between 480 and 500 F., and meets U. S. P. requirements on the acid test; has an unsulphonatable residue of 97% or higher, and a pour test of 25 F. with a water white color. The particular material referred to has practically no odor. are entirely satisfactory'for operation of the machine, except that the kerosene odor is usually undesirable in the finished product and is difiicult to remove;

We prefer to use a very thin film of the releasing agent. A pad of fibrous material, such as gauze, resting on the surface of the seal roll, which pad is moistened with the releasing agent from time to time, gives a useful rate of feed.

To more easily enable the understanding of our improvement, a particular embodiment thereof is shown in the attached drawings in which:

Figure 1 shows the gelatin capsule machine, embodying our invention.

Figure 2 shows the new sealroll'in operation against a cavity die roll.

Figure 3 shows an alternative form of seal roll in which a resilient cushion is used for part of the compression.

As shown in Figure 1 a lower gelatin film H which may be supplied from any standardgelatin casting means and which may be oiled on the die roll'contacting side and whichmay be coated with an interior coating such as gum benzoin on the interior side is fedonto acavity die roll l2. Certain details of this cavity die roll are described and claimed inour co-pending application Serial No. 164,426 filed May 26, 1950.

As more clearlyshown in Figure 2, the-cavity die-roll l2-has in its surface aseries of capsule forming cavities 13. At the bottom of each cavity is at least one capsule ejector plug M. As the gelatin film comes in contact with the cavity die roll as it rotates, it is pulled down into the capsule forming cavities by theeffects of reduced pressure thereby forming a gelatin lined capsule forming cavity or capsule shell l5.- As the cavity die roll rotates, a seriesof such capsule shells are uniformly and continuously formed in the lower gelatin film. As these-cavities pass by position A shown in Figure 2, the capsule contents l6 may be discharged into thepassing series of shells.

As shown in Figure 2, the contents area liquid,

Kerosenes which have an odor 4 which may have suspended solids to form a paste, which is uniformly discharged from a liquid nozzle H. The liquid may be uniformly discharged by a constant flow means such as a gear pump i8 which may be driven through a suitable variable drive means so that the rate of flow may be adjusted. The nozzle uniformly and continuously discharges its contents into the passing capsule shells. Even though not measured the charges in the individual shells are extremely uniform. Usually a variation of less than 1% occurs in production operations.

By using a nozzle which does not touch the inner side of the gelatin film, it is convenient to fill capsule shells which are formed in a film which is coated'with a sticky lining. A layer of a material such as gum benzoin may be applied to the gelatin film. It adheres to both the unstretched film as well as the stretched portions forming the shell, and provides a tenacious protective layer which isolates the gelatin film and the capsule contents. Prior machines using a filling shoe which rests on the film, such as shown by Donofrio 2,513,852, cannot use such a coating because it would adhere to the shoe.

The capsule contents may be either a liquid or a paste, a liquid having solid particles therein; or a powder filling mechanism may be-used to fill powdered contents into the individual capsule shells. Such a powder-fillingmechanism is shown in more detail in ourapplication Serial No. 164,426 filed May 26,- 1950. The series of thus filled capsule shells rotate towards the contact with the seal roll.

The seal roll is is suitably journalled on bearings 20 in a support frame Zlso that'positioning rods 22 urge the seal roll into contact withthe cavity die roll. The positioning rods are in turn spring loaded by means of a hold-down spring 23 and a yoke 2 The-tension of the spring is adjustable by means of an adjusting handle 25; The seal roll itself may have integral heater elements 26 therein; The heater elements are diagrammatically shown as electrical resistances because such resistances are'particularly convenient although other sources of heat may be used. A- thermostat 21 controls the energy supplied to the seal roll soas to maintain the temperature as desired. The thermostat and leads may be on the rear roll. The sealroll may havea valve plate 28 on one side thereof and bearing against the-seal'roll so that over a portion of the periphery of its travel a chest 29 is in contact with the ends of pressure; control duets 3U.

The pressure chest 29 is connected to a 3-way valve 3| whereby the pressure control ducts .and the chest may be either connected'to the vacuumsystemor to the atmosphere. As later indicated, it will be seen that depending upon thechoice of operation either a negative or atmospheric pressure may be used in this chest.

Adjacentto the seal roll ls'andpositionedby the frame 2l'is a support plate 32. Above the support plate and adjacent thereto'are'wiperretaining rods 33. Between the. wiper retaining rods and'the support plate is placed a wiper. 34

which may conveniently be a gauze pad or' other textile fabric or fibrous pad. This fibrous pad which serves as a wiper is positioned against the seal roll by the operator and moistened with kerosene. For pharmaceuticalpurposes, as previously described, it is desired that anodor-free kerosene be used; The-keroseneis supplied to the rotating seal roll by this wiper. It is desired that an extremely thin kerosene film be used.

and accordingly the wiper is moistened but slightly. In operation, a kerosene-filled oil can may be used and the rag moistened every hour or so by several drops of kerosene, or more conveniently, a drip oiler filled with kerosene may be used and set to drop a single drop of kerosene every several minutes. The speed of operation, temperatures, the exact kerosene fraction etc. will cause a variation in the requirements for the thinness of the kerosene coating. The operator can easily tell by inspection whether or not sufiicient of the releasing agent is being fed to the roll. If the gelatin film starts to stick to the roll, more of the releasing agent is needed. If the film starts to skid and give an uneven seal, less is needed. After a short period of operation, the rate of feed is easily determined.

The upper gelatin film 36, which also may be.

coated on theinside with a gum such as gum benzoin or other interior coating materials as desired, is fed against the upper seal roll, and carried by the upper seal roll around towards the bite or line of contact of the two rolls. The upper seal roll may be operated at a slightly higher temperature than the cavity die roll, so that the film strip contacting th up per seal roll is warmed. Either the upper roll may be heated or a, heater 3? of the radiant type caused to radiate heat against the gelatin film. If the seal roll itself is used as the sole heating means, it is necessary that a vacuum be pulled in the pressure control chest 29 so as to pull the upper gelatin film against the seal roll for heat transfer. The film may be released just before the point of seal so as to permit the elasticity of the film to act against the contents of the capsule shell and reduce the tendency towards formation of air bub" bles. The thus temperature-conditioned upper gelatin film rotates towards the contact with the lower gelatin strip which contains the filled capsule shells as illustrated in Figure 2.

As shown at A in Figure 2 the upper gelatin strip approaches the lower strip, and as shown at B the coating edges of the capsule forming cavities cut through the two gelatin films causing them to unite. The displacement of the two gelatin films downward by the interaction of the two rolls causes part of the capsule forming portions of the upper gelatin film to be pressed into the depression as in the seal roll. These depressions should be large enough so as to receive the entire displaced portion from the capsule forming cavities. The volume is approximately that of the two gelatin film strips over the area of the cavity.

Because the upper gelatin strip presses against the capsule contents and because of the elasticity of the film, there is a tendency forair bubbles to escape as the rolls approach. The capsule contents are more viscous and are entrapped, thereby giving uniform and consistent capsules. As the two rolls rotate, the cutting out rims of the cavity dies cut through the two gelatin films causing them to unite with each other as shown at C in Figure 2. The residual web may be held against the seal roll and then drawn oif to be re-melted and re-used.

The capsule forming cavities containing the completed capsules continue rotation as shown in D until the release point where the completed capsules 4| are rejected from the cavity dies, as shown in Figure 1. This phase of the capsule forming operations is disclosed in our earlier applications above referred to.

zofyvarious sizes of capsules in a single pair of rolls,

6" We havev found that by varying the size'and the shape of the depressions of the cavity die roll and by leaving the capsule shells slightly less than level filled, it is readily possible to manufacture capsules of a smaller size than would be obtained by completely filling the capsule shell.- It is therefore possible for the operator to manufacture different sizes of capsules with a singlecavity die roll by varyingthe seal roll. As will be obvious to those skilled in the art, the. seal roll is much the less complicated of the two, and the size variation is thus much more economically obtained than if it were necessary to have two sets of rolls for each size.

If a resilient insert All as shown in Figure 3 be used in each of the depressions, it is convenient to let the resilient insert, which may be of r a soft rubber, absorb any size variation in the capsules and it is then convenient to manufacture the size variation being determined by the rate of feedv of capsule contents into the capsule shells.

Various modifications in the exact size and,

shape of the die rolls will suggest themselves to those skilled in the art of capsule manufacturing.

Having thus set forth certain'preferred embodiments thereof, as our invention we claim:

1. A method of controlling the adhesion of a gelatin strip to a capsule machine roll, which 1 comprises coating the roll with a thin layer of kerosene, then contacting the roll with a gelatin strip whereby sliding of the gelatin strip on the roll is prevented, but the stri will release from the roll after capsule formation.

2. A die roll system for a gelatin capsule machine which includes a cavity die roll, capsule forming cavities therein, a rim surrounding each of said cavities, a juxtaposed seal roll comprising a substantially cylindrical rim contacting surface and a plurality of depressions therein, said de-' pressions corresponding in spacing to the said cavities, and of such dimensions as will permit said rims to contact the cylindrical portion of the seal roll, and the depressions being of such volume as to permit displaced portions of the capsule contents to be received therein during sealing of the capsule.

3. In combination in a gelatin capsule machine, a cavity die roll, capsule forming cavities therein, said cavities being large enough to hold both the bottom portion of the gelatin strip forming the capsule and the entire contents of the capsule, a rim surrounding each of such capsule forming cavities, a substantially cylindrical surface seal roll, the cylindrical surface of which is in rolling contact with said rims, a plurality of depressions in said seal roll in patterned relationship corresponding to said cavities, and a kerosene distributing means bearing on the surface of said seal roll whereby said seal roll is constantly coated with a thin layer of kerosene.

4. The combination of claim 3 in which the kerosene distributing means is a stationary fibrous pad.

5. The combination of claim 3 in which the kerosene distributing means is a gauze pad.

6. In the process of manufacturing soft gelatin capsules the steps which comprise continuously supplying a lower gelatin group, passing said lower strip in contact with a rotating cavity die roll, applying vacuum to cavities in said die roll to pull the strip thereinto, thereby forming a series of capsule shells in said strip, filling each of said capsule shells with the contents of a single capsule, supplying an upper gelatin strip,

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coating a seal roll with a thin layer of kerosene, passing said upperstrip into contact with the kerosene coated seal roll, rotating the upper gelatin strip into contact with the filled capsule shell containing lower gelatin strip, sealing together and cutting out the portions of each strip adjacent the filled capsule shells, thereby forming capsules, and separating said capsules and the residual strips from the rolls and each other.

7. In the processof manufacturing soft gelatin capsules the steps 7 which comprise continuously supplying a lower gelatin strip, passing said lower strip in contact with a rotating cavity die roll,

applying vacuum to cavities in said die roll topull the strip thereinto, thereby forming a series of capsule shells in said strip, filling each of said capsule shells with the contents of a single capsule, supplying an upper gelatin strip, heating a seal roll to a higher temperature than the cavity dierroll, coating the seal roll with a thin layer of kerosene, passing said upper strip into contact with the kerosene coated seal roll, rotating the upper gelatin strip into contact with the filled capsule shell containing lower gelatin strip, sealing together and cutting out the portions of each strip adjacent the filled capsule shells, thereby forming capsules, and separating said capsules and the residual strips from the rolls and each other.

8. In the process of manufacturing soft gelatin capsules the steps which comprise continuously supplying a lower gelatin strip, passing said lower strip i contact with a rotating cavity die roll, applying vacuum to cavities in said die roll to pull the strip thereinto, thereby forming a series of capsule shells in said strip, filling each of said capsule shells with the contents of a single capsule, supplying an upper gelatin strip, coating a depression-containing seal roll with a thin layer of kerosene, passing said upper strip into contact with the kerosene coated seal roll, rotating the upper gelatin strip into contact with the filled capsule shell containing lower gelatin strip, the

applying vacuum to cavities in said die roll to pull the strip thereinto, thereby forming a series of capsule shells in said strip, filling each of saidcapsule shells with the contents of a single capsule, supplying an upper gelatin strip, coating a seal roll with a thin layer of deodorized kerosene, passing said upper strip into contact with the deodorized kerosene coated seal roll, rotating the upper gelatin strip into contact with the filled capsule shell containing lower gelatin strip, sealing together and cutting out the portions of each strip adjacent the filled capsule shells, thereby forming capsules, and separating said capsules and the residual strips from the rolls and each other.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 641,623 Chorley Jan. 16, 1900 947,457 Ratignier et a1 Jan; 25, 1910 2,288,327 Scherer June 30, 1942 2,323,581 Weckesser July.6, 1943 2,387,747 Cowley Oct. 30, 1945 2,513,852 Donofrio June 4, 1950 OTHER REFERENCES Hackhs Chemical Dictionary, 3rd ed., 1944, page 635, published by The Blakiston Co., Philadelphia, Pa.

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