“Funnel” covers several different jobs: gravity filtration, liquid–liquid extraction, and vacuum filtration. Choosing the right family first is more important than comparing prices within the wrong category.
| Type | Job | Key choice |
|---|---|---|
| Conical filter funnel | Gravity filtration | Top diameter, stem length, glass or PP |
| Separatory funnel | Liquid–liquid extraction | Volume, stopcock material, joint size |
| Buchner funnel | Vacuum filtration | Filter diameter, frit porosity, flask fit |
| Fritted filter funnel | Fine filtration | Pore size G1–G4, cleaning method |
Conical funnels are simple and effective for coarse filtration with paper. A long stem improves the liquid column and speeds flow; a short stem is easier to clean. Plastic (PP) funnels are durable and inexpensive; glass funnels are easier to see through and resist many solvents.
For extraction, the stopcock is the critical part. PTFE stopcocks resist most solvents and do not require grease; glass stopcocks need careful greasing and can seize. Match the joint size to your flask, and choose a volume that leaves room for shaking and venting.
Vacuum filtration needs a Buchner funnel, a filter paper or frit, and a suction flask. Frit porosity matters: G1 is coarse, G4 is fine. A fine frit clogs faster with particulate samples; a coarse frit may pass fines. For sticky or biological samples, a paper filter on a Buchner funnel is often easier to clean than a frit.
We supply conical, separatory, Buchner and fritted funnels in glass and plastic. Send the volume, pore size or joint size and the filtration method; we will confirm the exact item and lead time.
Use a Buchner funnel with a suction flask and a suitable filter paper or frit. Match the funnel diameter to the paper and the flask.
G1 is the coarsest and G4 the finest. Choose based on the particle size you need to retain and how quickly the frit may clog.
Glass is autoclavable and solvent-resistant; PP is durable and economical for aqueous work. Choose based on solvent and cleaning needs.
PTFE is the usual choice because it resists most solvents and does not need grease. Glass stopcocks require careful maintenance.
Yes, by back-flushing with a suitable solvent. Avoid scraping the frit with metal tools, which can damage the pores.
Tell us the sizes, quantities and sterility requirements. We reply within 2 hours on business days.
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