The PTFE Buchner funnel and its suction filtration device---Nanjing binglab

The PTFE Buchner funnel and its suction filtration device are an instrument used in the laboratory to filter using vacuum or negative pressure suction.

Buchner’s funnel is in the shape of a flat cylinder with many small holes on the bottom of the cylinder. Connected with a long and narrow cylindrical exit.

When using, generally put filter paper on the bottom of the cylinder, insert the funnel into the upper opening of the Buchner flask and seal the interface (for example, with a rubber ring). The side port of the Buchner flask (generally recommended to use polytetrafluoroethylene) is connected to the exhaust system. Then pour the solid and liquid mixture to be separated into the top, the liquid component is drawn into the flask under negative pressure, and the solid remains on the top.

It is often used to extract crystals in organic chemistry experiments. In this case, after the filtration is completed, a small amount of pure solvent can be used above to wash off the impurities on the crystal surface.

Use of the Buchner funnel

Wet the filter paper with water first, and pump it so that the filter paper is close to the bottom of the funnel, which can prevent the things to be filtered from leaking. Pour in the filtrate, turn on the machine to pump, you can stir it a little, and only the filtered substance remains.

It is not acceptable to directly use an ordinary funnel, paste the filter paper, and then connect the air pump for suction filtration (replacing the Teflon Buchner funnel). Because the walls of the funnel are close to the filter paper, negative pressure suction filtration does not work on it. Only the lower top corner of the funnel produces a pressure differential. Since the mouth is large and there is only one mouth, it is easy to break. (wet filter paper is not firm)

Features of PTFE Buchner funnel:

1. Can replace the ceramic Buchner funnel on the market to avoid chipping

2. Strong corrosion resistance: can withstand strong acid and alkali, aqua regia, magic acid, hydrofluoric acid and other organic reagents

3. Pure white appearance, high temperature resistance: operating temperature -200～250℃

4. Anti-pollution: The blank value of metal elements is low. Lead and uranium content less than 0.01ppb

5. Non-stick surface, easy to clean

6. Filtration using vacuum or negative pressure suction can also be matched with a suction filter bottle for vacuum filtration of crystals or coarse precipitates in inorganic preparation to prevent corrosive solvents from splashing

7. Buchner funnels of various specifications and matching suction filtration devices can be customized according to customer requirements