For some reactions, it is nescessary to maintain the reaction under a flow of a gas rather than using balloon/septa techniques to hold a reaction under a modified atmosphere. There are a number of possible circumstances where this is desirable:

• A gas is produced during the reaction, and a setup is required where the generated gas can be safely vented from the reaction and the reaction remains under the desired gas being introduced to the reaction.

• A gas is consumed during the reaction and it is nescessary to ensure the pressure doesn't reduce during the reaction.

• It is nescessary to 'degas' the reaction solvent, where a gas (typically nitrogen) is bubbled through the solution, and the setup needs to allow this gas flow to be released from the setup.

There are two separate components to these setups, which may be used individually, or more common in combination. These two components are:

• A nitrogen bubbler which usually consists of a ground-glass joint (cone) which can be placed into the socket of a round bottomed flask or condenser. These usually have an attachment for a nitrogen inlet and an oil bubbler outlet. The oil bubbler outlet allows the flow rate of the gas to be observed.

• A Pasteur pipette setup which is used to bubble a gas through the solution in the flask.