It is a Bolt Neck Heavy Wall Filtering Flask With Tubulation.These Flasks are cast in special moulds.It comes in various capacities according to the requirement. It is designed to impart maximum mechanical strength. The neck finish is designed for strength and to ensure good stopper fit. These flasks are bottle shaped. It is made of heat resistant borosilicate glass. This flask is also called a Büchner Flask, vacuum flask, filter flask, side-arm flask or Kitasato flask.It is a thick walled Erlenmeyer flask with a short glass tube. The short tube and hose barb effectively acts as an adapter over which the end of a thick-walled flexible hose (tubing) can be fitted to form a connection to the flask. The other end of the hose can be connected to source of vacuum such as an aspirator, vacuum pump, or house vacuum. Preferably this is done through a trap which is designed to prevent the sucking back of water from the aspirator into this flask.
It’s thick wall provides it the strength to withstand the pressure difference while holding a vacuum inside. This flask is primarily used together with a Büchner funnel fitted through a drilled rubber bung or an elastomer adapter (called Büchner ring) at the neck on top of the flask for filtration of samples. It can also be used as a vacuum trap in a vacuum line to ensure that no fluids are carried over from the aspirator or vacuum pump to the evacuated apparatus or vice versa.
