Ensuring the headspace of a vial contains a specific gas

Expertise Series

When confronted with the task of ensuring that the headspace of a vial contains a customer specified gas there are several options available. However if the evacuation of atmospheric gasses and replacement with a specified gas is critical and must be verified, the challenge requires specialized equipment.


Most gassing systems used today are passive systems which flush a vial with gas in order to displace the atmospheric gas with the new gas. This is a generally reliable system for open vials when the evacuation of the original gas is not 100% critical. When the removal of the original gas is critical to the function of the product in the vial, more aggressive techniques must be employed to ensure the removal of the original atmosphere.

Bosch has recently introduced a continuous motion rotary de-gas machine, RCV 3480, capable of processing vials with partially inserted Lyo stoppers. The RCV 3480 performs multiple evacuation flush cycles of the headspace gasses before it mechanically seats the stoppers. The RCV is able to run at a rate of up to 450 vials per minute.

Immediately after the liquid filling station, lyo stoppers are partially inserted into the vials. Lyo stoppers are used to allow a passageway for the degassing/gassing procedure.

Clean Turret PhotoAs a partially stoppered vial comes into one of the 48 stations mounted on a rotary station, a bladder is inflated around the neck of the vial to seal the headspace.  Vacuum is applied to the vial at levels up to 28 inches of mercury, followed by a gas that is then sequentially introduced into the headspace. Each of these steps is verified via individual transducers located in each head. The number and duration of the flush/fill cycles can be adjusted by the operator depending on the speed of the machine. 

After the flushing process is completed, the lyo stopper is seated, sealing the vial while still in one of the 48 stations. Once seated, the vial is now sealed to the atmosphere and exits the rotary degasser. Vials can then be sent to a conventional capper.    

All utilities for the RCV 3480 are routed through a rotary union and distributed to each head and are electronically controlled individually via isolation valves.  Stainless steel process parts are passivated and cleaned for oxygen service. All process parts can be cleaned or flushed using vaporized hydrogen peroxide.   

The servo driven system uses a PLC via Ethernet and a slip ring to control all on board process steps. The system is capable of running multiple recipes, displaying critical process data and tracking each vial through the machine via a shift register. Any rejected vial is flagged and later ejected and removed from the flow by a vacuum starwheel to a reject station.

With the increasingly complex requirements demanded by manufacturers, this novel solution provides an effective way of dealing with products sensitive to atmospheric gasses.

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