Porcelain Buchner Funnel - Glazed

A glazed porcelain Buchner funnel with a thin stem, made for vacuum filtration. It's glazed inside and out except for the top rim, and it's designed to seal well and last. The glaze protects the porcelain from chemical attack.

Why the rim is left unglazed

• Porcelain has to rest on a surface while it is fired in the kiln. A bare rim can't fuse to the kiln shelf or firing rack, and it lets the funnel be handled and turned over safely while it's being made.
• The unglazed rim has a slightly textured edge, which helps prevent small chips when you turn the funnel upside down on a flat bench or stack funnels for storage.

Key features

• The smooth white glaze resists aggressive acids, organic solvents and alkalis almost completely. The exception is hydrofluoric acid.
• A flat porcelain plate with small, evenly spaced holes is fixed inside the funnel. It supports a round filter paper under strong suction, so the liquid pulls through evenly without tearing the paper.
• It handles extreme temperatures, resists sudden thermal shock and can be autoclaved for sterilisation.
• The thin stem tapers, so it slides into narrow-necked filter flasks without scraping the glass or getting stuck in the neck. The taper also lets liquid drain smoothly, stops splashing and prevents air locks.

Sizes

• 20mm O.D. (fits 13mm I.D. filter paper)
• 50mm O.D. (fits 40mm I.D. filter paper)
• 65mm O.D. (fits 55mm I.D. filter paper)
• 75mm O.D. (fits 65mm I.D. filter paper)
• 105mm O.D. (fits 90mm I.D. filter paper)
• 127mm O.D. (fits 110mm I.D. filter paper)
• 143mm O.D. (fits 125mm I.D. filter paper)
• 172mm O.D. (fits 150mm I.D. filter paper)
• 210mm O.D. (fits 185mm I.D. filter paper)
• 270mm O.D. (fits 240mm I.D. filter paper)
• 300mm O.D. (fits 285mm I.D. filter paper)

Specifications

• Material: dense laboratory porcelain
• Finish: glazed over the whole inside and outside to protect against chemicals, except the top rim, which is left unglazed so it can't fuse in the kiln
• Filter plate: fixed perforated plate with evenly spaced drain holes to support round filter papers
• Stem: thin and tapered, to fit narrow flask necks, avoid vacuum bottlenecks and run liquid cleanly down the side wall of the flask
• Chemical resistance: organic solvents, aggressive acids and alkalis (not hydrofluoric acid)
• Temperature: safe for autoclave sterilisation, and stable through rapid temperature changes up to 1,000 °C without the glaze softening
• Country of origin: India