- Gas Expansion Pycnometer
Also known as constant volume gas pycnometer, it comprises two chambers – sample and reference. A sample is put in the sealed chamber located in the pycnometer. Then, the pressure is applied as per the target measure. The readings are recorded. The opening of the expansion valve situated between the sample chamber and reference chamber let the gas expand to the reference chamber. This, in turn, creates a pressure drop ratio which verifies the density/volume of the said sample. It does so by comparing the recorded readings to the volume of a standard measured earlier through a similar process.
- Variable Volume Pycnometer
Also known as gas comparison pycnometer, it consists of single or dual variable volume chambers. The cell volume for the sample can vary according to types and size. After the sample is placed in the sample chamber, a piston is placed at the initial position simultaneously. Then the valve is opened and gas is filled in pycnometer. The valve is closed after which the initial gas pressure in the pycnometer is measured using an absolute pressure transducer. The piston is moved to another position to measure the final pressure.
A pycnometer is very important science laboratory equipment for scientific and many other types of research.