Filtering Funnels
Filtering Funnels
Filtering funnels, also known as Buchner and Hirsch funnels, include a cylinder separated from the funnel with a fritted glass disc or perforated plate. Fritted glass disc funnels are immediately ready for use, while perforated plates call for filter paper moistened with liquid to prevent initial leakage.
Vacuum suction then draws the liquid through the filter and into the cylinder. Porcelain filtering funnels are resistant to acids and alkalis, except for hydrofluoric acid, but should not be used in the filtration of extremely corrosive reagents, which can slowly corrode their protective enamel. The funnels are glazed both outside and inside, except the rim, and are autoclavable.
What Is a Buchner Funnel Used for?
Buchner funnels are used in the laboratory for vacuum-assisted liquid filtering. In organic chemistry, these funnels are used to collect recrystallized compounds because they help remove moisture from the final product.
How Does a Buchner Funnel Work?
Buchner funnels consist of an open straight-sided cylindrical chamber that narrows to a tube- or pipe-shaped opening. The tube-like extension can be placed through a stopper, which is then placed into the top of a filtration or Buchner flask. Plastic versions may have a bung hole located at the side of the chamber to which a vacuum may be attached. Buchner funnels are reusable.
What Types of Buchner Funnels Are There?
The bottom of the Buchner funnel chamber may be perforated or contain a separate fritted disc. Filter paper is used for Buchner funnels with perforated lower surfaces. Place the filter paper of the preferred porosity inside the chamber, pre-wet, add the liquid, and apply the vacuum.
Filtration with a Buchner funnel proceeds more quickly than letting the liquid flow simply using gravity. Most Buchner funnels are also rated for a maximum vacuum pressure.
Quickfit™ Glass Büchner Funnel with Glass Sintered Disc
Used in place of conventional filter papers that would be destroyed by acids and alkalis. Quickfit™ Glass Büchner Funnel with Sintered Glass Disc is manufactured from chemical-resistant borosilicate glass. Integral ground glass cone on stem connects to Quickfit™ Büchner flasks and vessels.
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Haldenwanger™ Porcelain Buchner Funnel
Use these funnels for a variety of filtration applications. Haldenwanger™ Porcelain Buchner Funnels are constructed from optimized laboratory porcelain.
Lenz Laborglasinstrumente™ Microfilter Funnels
Created from borosilicate glass. Lenz Laborglasinstrumente™ Microfilter Funnels are ideal for concentrating organisms in fluid samples.
Lenz Laborglasinstrumente™ Borosilicate Glass Conical Filter Tube
Made of DURAN™ borosilicate glass. Lenz Laborglasinstrumente™ Borosilicate Glass Conical Filter Tubes are used for filtration of very small volumes and is highly resistant to most chemicals such as solvents, acids, and alkalis.
Lenz Laborglasinstrumente™ Filter Funnels
Made of borosilicate glass. Lenz Laborglasinstrumente™ Filter funnels are ideal for separating solids from liquids via laboratory filtration.
DWK Life Sciences DURAN™ Filter Funnel, conical shape
The filter funnel has a melted filter plate and is used for filtration without vacuum. When using the filter funnel, a filter paper can be dispensed with.
Bel-Art™ SP Scienceware™ Buchner Table-Top Funnels, 18 in. (45.7cm) I.D.
Filter large volumes quickly with a polyethylene plastic Table-Top Buchner Funnel.
Bel-Art™ SP Scienceware™ Buchner Table-Top Funnels, 10.25 in. (26cm) I.D.
Filter large volumes quickly with a polyethylene plastic Table-Top Buchner Funnel.
Fisherbrand™ Glass Funnel Filter with Sintered Glass Disc
Constructed of borosilicate glass and available in a variety of capacities. Fisherbrand™ Glass Funnel Filters with Sintered Glass Disc filter medium precipitates ranging from 16 - 40μm and 10 to 14μm pore sizes respectively.
Kartell™ Polypropylene Buchner Funnels
Manufactured from robust, lightweight polypropylene for durability and excellent chemical resistance. Kartell™ Polypropylene Buchner Funnels with an integral filter is ideal for separating solids from liquids in a laboratory.
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Robu™ Büchner Filter Funnels with Porosity 2 VitraPOR™ Glass Filter Discs
Robu™ Büchner Filter Funnels with Glass Filter Discs are made of pure borosilicate 3.3 glass and are highly resistant to most chemicals, including solvents, acids, and alkalis. The VitraPOR™ filter disc is rated as Porosity 2 (Pore size: 40 to 100 μm, Standard: ISO 4793-80).
Robu™ Borosilicate Glass Buchner Filter Funnels
Filter Funnels are made of pure borosilicate glass 3.3. This versatile and recyclable material offers excellent properties for the most diverse fields. It is highly resistant to most chemicals such as solvents, acids and alkalis.
DWK Life Sciences DURAN™ Filter Crucible
Filter crucibles are filters that are used like filter chutes in solid-liquid separation by means of vacuum. They are particularly suitable for precipitation, which must be dried to a constant weight.