Handling Break-Seal Glass Flasks
Chemie Blocks
Handling Break-Seal Glass Flasks
When you order gaseous products from Chemie Blocks in Break-Seal Glass Flasks, they are shipped in volumes up to a 0.5 litre size and packed at atmospheric pressure. The flask is closed with a glass break-seal so that the gas can be transferred to another vessel using the below method.
We would suggest that it would be advantageous to conduct a simulated dry run of the various steps in the sequence outlined below to ensure that the procedure is fully understood.
This will also ensure that all necessary equipment is available at hand for immediate use.
Diagram 1
- Gently insert a metal magnet (or a glass coated magnet if metal is incompatible with the gas) into the neck of the flask containing the labelled gas.
- With the flask neck held horizontally, use a second magnet on the outside to carefully guide the inner magnet to the glass seal (see Diagram 1).
- With the flask neck horizontal, gently insert an inner magnet, then carefully use an outer magnet to guide the inner magnet close to the area of the break-seal.
Diagram 1
Diagram 2
Diagram 2
- Using tubing that is chemically compatible with the gas, connect the flask to your vacuum system.
- Evacuate the tubing, then close the valve to the pumping system before breaking the seal (see Diagram 2).
- For a more controlled release of the gas, prior to breaking the seal, condense the gas as a liquid by cooling the bottom tip of the flask in dry ice or liquid nitrogen.
- Evacutate the tubing and system, then close off the valve. The gas may be condensed in the bottom tip if required.
Diagram 3
- Use the outer magnet to move the inner magnet up and down the stem of the flask, gently tapping the seal until it breaks (see Diagram 3).
- Sometimes repeated tapping or even trying a different area of the tip may be necessary to break the seal.
- Using the outer magnet, raise the inner one up and down gently against the break-seal until the tip breaks.
- The valve can now be opened to a connected reaction vessel and the gas can be transferred (please ensure first that the pump has been closed off from the reaction system).
- The transfer may be facilitated by slightly warming the break-seal glass flask while simultaneously cooling a previously evacuated or partially evacuated reaction vessel.
Diagram 3
