Liquid filled capsules

Capsules are filled with liquid-fill by introducing the liquid into a capsule body held in an upright orientation. A capsule cap is fitted over an open end of the capsule body to close the capsule. The closed capsule is held in the upright orientation until the contents have stabilised. The holding period allows excess pneumatic pressure to be dissipated prior to sealing the cap to the body. The holding period may alternatively allow solidification of the liquid-fill. Advantageously, the closed capsules are held in an upright tube ( 4,6 ) in a vertical stack.

The apparatus for providing a holding period comprises an enclosure 2 containing a series of hollow substantially vertical tubes 4 , 6 which is arranged over the ejection station generally indicated as reference numeral 8 of a conventional filling machine. A conventional filling machine comprises a lower block 100 for holding a batch (for example 12) of capsule bodies and a corresponding upper block 102 for holding the respective capsule caps. Typical capsules are indicated as 104 , 106 . Ejection pins 108 , 110 are vertically moveable within the block 100 for vertically ejecting the filled closed capsules. According to the present invention, these filled closed capsules are ejected into the lower end of tubes 4 , 6 wherein they form a vertical stack. One capsule after another is ejected into the lower end of the stack until it passes out of the top thereof. The enclosure 2 comprises an inlet 9 and outlet 10 for passing cooling gas or liquid around the upright tubes for cooling them (particularly in the case of a molten liquid fill). A pneumatic-operated piston arrangement 12 is attached to a bracket 14 on the enclosure. The piston is arranged to lift the enclosure to enable removal of rejected capsules. It is known that conventional filling machines have a mechanism for diverting rejected capsules. This pneumatic arrangement thus operates to prevent reject capsules from entering the upright tubes. At the lower end of each tube are provided rubber retaining rings 16 for preventing the lowermost capsule falling back towards the ejection station. These may be in the form of a groove around the outside of the tube having a slot communicating with the interior of the tube across which the rubber ring is stretched. This constitutes a resilient detent over which each capsule must pass as it is ejected into the lowermost part of the tube. At the upper end of the tubes is provided an ejection block 20 which serves to direct the capsules ejected from the top of the tubes at the end of the holding period sideways into an ejected capsule chute 22 . The chute directs the ejected capsules towards a conventional collection area. The capsules are then carried forward to a sealing station where a band of sealing material is applied in conventional manner. The ejection block is formed of a plastics material machined to provide conduits 26 aligned with the upright tubes and communicating with an inclined upper space 24 leading towards the ejected capsule chute. The process is operated as follows. In a conventional machine the upper block 102 is aligned over lower block 100 and a batch of twelve prelocked capsules introduced into blocks 102 / 100 . The bodies are drawn from the caps into lower block 100 by applying suction thereto leaving the caps in upper block 102 . The lower block 100 containing the capsule bodies is then moved to a filling station wherein the bodies are filled with liquid. The lower block is then moved to a closing station where the caps are replaced over the open end of the bodies, by moving the bodies upwards into the caps into the fully locked position. The closed locked capsules are then moved to the ejection station shown in FIG. 1 . At the ejection station, ejection pins 108 , 110 move the filled closed capsules vertically into the tubes 4 , 6 and past the retaining rings 16 . The retaining rings prevent the capsule falling back to the ejection station. As further closed capsules are ejected into the lower end of the tubes, the tubes become filled with capsules. Each capsule is retained in the tube for the holding period until it is ejected via the ejection block 20 into the chute 22 . In the case of rejected capsules, the pneumatic piston 12 is operated to raise the assembly clear of the ejection station to allow the rejected batch of capsules to be diverted elsewhere. The residence time in the tubes is generally in the region 20-40 seconds, typically around 30 seconds. This allows sufficient time for excess pneumatic pressure to be released from the liquid filled capsule prior to collection of the filled capsules and passage to the sealing station where a band of adhesive solution is applied around the junction between the cap and the body.