GB755396A - Improvements in and relating to the manufacture of capsules - Google Patents

Abstract

755,396. Moulding capsules. GUNNELL CAPSULATIONS, Inc. Oct. 23, 1954, No. 30596/54. Class 87(2) Capsules are made and filled simultaneously by feeding measured charges of encapsulating material, e.g. gelatin, and filling material, e.g. medicament, in a liquid state into a mould in concentric streams and allowing the encapsulating material to harden so that it forms a seamless shell enclosing the filling material, the feeding of the encapsulating material commencing shortly before and terminating shortly after that of the filling material to ensure that the charge of filling material is completely covered. The mould is cooled or heated according to whether a thermoplastic or thermosetting encapsulating material is used. The apparatus shown comprises a series of cylindrical moulds 10 mounted on brackets 32 which are slidable vertically in arms 28 carried by an intermittentlyrotated hollow shaft 15, each mould comprising a jacket 14 through which cooling water is circulated by means of flexible pipes 16 and 17 connected to the shaft 15. The bottom of each mould is closed by a plunger 41, 43 which is held in position by a packing ring 42 and arranged to be moved upwardly by a plunger 44 at a discharge station to eject a completed capsule 13. A cam-actuated plunger 48, located at a station intermediate the discharge and filling stations, operates to return the plunger 41 to a predetermined position, the stroke of this plunger being adjustable to,vary the capacity of the mould. The brackets 32 are urged downwardly by springs 34, and each bracket is elevated at the filling station by a plunger 36 which is operated by a camactuated lever of adjustable length (see Fig. 3, not shown). The contour of the cam is such that the bracket is then lowered at the filling rate and finally returned quickly to its original level to break the stream of gelatin. The gelatin and filling material are delivered to successive moulds through a nozzle 51 comprising concentric tubes 52, 53 connected by pipes 58 and 83 and twoway valves 61 and 81 respectively to reservoirs 57 and 78, the valves being operated in synchronism with plungers 59 and 80 whereby measured charged of gelatin and filling material are drawn into chambers 62 and 82 and delivered to the nozzzle. The plungers are operated through links and levers by cams 65 and 96 on a shaft 66, the effective lengths of the levers being adjustable to vary the strokes of the plungers and hence the quantities delivered in accordance with the size of the moulds. The plunger 80 operates a lever 91 on the filling stroke to tension a spring 93 so that at the end of the stroke it is retracted quickly, to an extent determined by engagement of a screw 94 and stop 95, to break the column of filling material. The gelatin reservoir 57 and pipe 58 are surrounded by a jacket through which a heated liquid is circulated, and the filling material reservoir 78 and pipe 83 are surrounded by a similar jacket through which a coolant is circulated.