Vacuum filtration is a quick technique for separating a solid from a liquid. The water flowing in the water pump draws air from the vacuum flask, and the contents of the Buchner funnel are sucked into the flask (a filter placed in the bottom of the funnel separates the solid from the liquid). The solid remaining in the funnel is then recovered more easily and is much drier than during simple filtration. The conical seal makes it possible to seal the assembly, preventing the passage of air between the Buchner funnel and the vacuum flask. It maintains the vacuum in the assembly and also avoids physical constraints (glass against glass).

Composition:

• A vacuum flask 250 mL Boro glass 3.3
  
• A polypropylene water pump
  
• Polypropylene Buchner funnel (Ø 70 mm)
  
• Two tapered seals
  
• Vacuum pipe - length 1 meter (Øint 8 mm - Øext 16 mm)