A Pressure Equalizing Funnel (Jointed and Graduated) is a specialized piece of laboratory glassware used for the controlled addition of liquids into a closed system, such as a vacuum or inert-gas environment. It is characterized by a side tube that balances internal pressure, allowing reagents to flow smoothly without needing to remove the stopper.
Key Component Specifications
- Pressure Equalizing Arm: A narrow-bore glass tube connecting the top of the funnel to the stem below the stopcock to ensure constant pressure.
- Graduations: Features high-visibility markings (often white enamel) to measure the exact amount of liquid being dispensed.
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Jointed Connections: Equipped with standard taper ground glass joints:
- Top (Female/Socket): For attaching a stopper or condenser.
- Bottom (Male/Cone): For secure insertion into a reaction flask.
- Common Sizes: 14/23, 19/26, 24/29, or 29/32.
- Material: Made from Borosilicate 3.3 glass, which provides excellent thermal shock resistance and chemical durability.
Operational Tips
- Inert Environments: Essential for handling air-sensitive reagents where maintaining a sealed system is critical.
- Stopcock Choice: PTFE stopcocks are preferred for high-purity or corrosive work as they do not require grease and won't "freeze".
- Cleaning: For grease-free performance, use PTFE stopcocks; if using glass stopcocks, ensure they are lightly greased to prevent jamming.