Focusing on Funnels

Funnels are basically pipes with wide, conical mouths that end into narrow tubes. They are used in transferring liquid, fluid and other fine-grained substances into containers that have small openings, preventing spillage during the process.

Most funnels are usually made of plastic, glass, stainless steel or porcelain. The material should be strong enough to withstand the mass and force of the substance being transferred. Also, it should not create any adverse reactions to the substance.

Glass is most commonly used for laboratory funnels as it does not react to many substances, unlike funnels made from metals or plastics. In transferring aqueous solutions, plastic funnels made of polyethylene can also be used. Plastic is also the material utilized for funnels used in transferring powdered substances that cannot come into contact with solvent during transfer. Powder funnels have wide mouths and short stems that do not clog easily.

There are many other different kinds of funnels used for specialized and specific applications in the laboratory. A few of these funnels are filter funnels, thistle funnels (so called because they resemble thistle flowers), and dropping funnels.

Dropping dropper funnels, also called tap funnels, usually have stopcocks that allow the fluids to be slowly transferred to another container. Dropper funnels have taps and valves that allow the controlled release of a liquid.

Buchner and Hirsch funnels, two types of funnels usually used with filter papers can be used to remove fine particles from a liquid mixture in a filtration process. More demanding processes use a sintered glass first instead of filter papers.

Another type of funnel is separatory funnel. These are used in liquid-liquid extractions. This process involves separating a form of liquid mixed to another liquid. Disposable paper funnels, another type of funnels, are used in messy processes where it would be difficult to clean the funnel after the transfer, such as in transferring motor oil to a car.