DURAN® Dropping Funnel, with Ground Joints and Pressure Equalisation Tube, Cone NS 19/26, 100 mL

These dropping cylinders are ideal for the measured addition of solutions, reagents and/or chemicals to a reaction mixture. The double graduated scale shows the approximate volume of liquid contained in the funnel or the volume dispensed from the funnel. Pressure-equalising dropping funnels have an additional narrow-bore glass tube from the bulb of the funnel, to the ground glass joint around the stem. These replace the liquid volume lost in the bulb with the equivalent gas volume from the flask into which the reagent is flowing, and are useful when handling air-sensitive reagents in a sealed, inert-gas environment. Without this tube, or some other means to equalize the pressure between a sealed receiving flask and the bulb of the funnel, the flow of fluid from the bulb will stop.