Gasometer

GASOMETER (from French gaz—gas and Greek metron—measure), a vessel used in laboratories for collecting (and also for measuring) gas, from which the collected gas can be dispensed as desired. Depending on the properties of the gas being collected (carbon monoxide, carbon dioxide, chlorine, sulfur dioxide, hydrogen, etc.), metal or glass gasometers are used. The figure shows a very common type of laboratory gasometer of the Mitscherlich system—a glass vessel with metal connecting parts, with a capacity of 16 liters. To use it, it is first filled with water through funnel A, after having previously opened taps a and b; then

these taps are closed.

the screw-on

c is removed,

and gas is admitted from the gas generator through tube b. As the gas is admitted, the water flows out of the lower opening. Upon filling the vessel with gas, cap c is screwed on and tap b is closed. When tap a is opened, water rushes from the funnel into the vessel, and the gas, acquiring a pressure corresponding to the water column, is displaced through tube b and used as required. Due to the transparency of the vessel, one can always judge by the water layer what amount of gas is present in the gasometer. In metal gasometers, which are built on the same principle, water-gauge tubes running the entire height of the vessel are provided for this purpose. Gases strongly absorbed by water, such as sulfur dioxide, are collected not over water, but over mercury. Small Bunsen mercury gasometers are convenient for this purpose. For collecting chlorine, chlorine gasometers are used, similar to the one shown in the figure, but manufactured without metal parts, exclusively from glass, with ground-in glass parts.

F. Budagyan