Volumeters

A volumeter is an instrument designed to determine the volume of a material or cavity. The term covers devices used to measure the volume of liquids, solids, and gases, whether by displacement, pressure measurement, or other physical principles. Volumeters are used in laboratories and manufacturing to obtain quantitative volume data essential for density calculations, porosity assessments, formulations, and quality control.

Displacement-based volumeters determine volume by the amount of liquid displaced when a sample is immersed. A sample of irregular shape is submerged in a calibrated liquid-filled container; the change in liquid volume or the buoyant force exerted on the sample yields the sample’s volume. Devices of this type include immersion methods and pycnometers, which have a known container volume and are used with a solvent to deduce the volume via mass measurements.

Gas or vapor volumes can be measured with volumeters that relate pressure, temperature, and amount of gas, applying the ideal gas law or calibrated standards. Some volumeters use differential pressure or flow measurements to determine the volume of a closed chamber or cavity.

Accuracy in volumetry depends on temperature control, proper calibration, and an understanding of liquid density, surface tension, and buoyancy effects. Volumeters find use in chemistry for solvent and solid measurements, in materials science for density and porosity, in geology for rock and sediment volumes, and in quality control for absorptive and composite materials.