LIQUID DENSITY MEASUREMENT

During gas density measurements, when variations in pressure and temperature are small, the temperature and pressure act Difficulties in THE measurement of densities of fluids are due to complexities in processes, venation of fluid dens[i.e!; witting the process, and the diverse characteristics of the process lndfluids governesses. Some of these methods arc: custom designed and applicable to special cases only. Others are very similar in principles and technology, and can be used for many different types of fluids. Presently, apart from conventional methods, many advanced techniques have been developed, for example, density meters based on electromagnetic principles, which are intelligent instrumentation systems. 

Depending on •the applications, fluid densities can be measured both .in static or dynamic forms. In general, static density measurements of fluids are well-developed, precise, and have greater resolution than most dynamic techniques. Chronometer and buoyancy are examples of static techniques that can be adapted to cover small density ranges with a resolution and precision, 

'Today, many static density measurement devices are computerized, coming with appropriate supporting hardware and software. In general, static type measurements. are employed in laboratory conditions, and dynamic methods are employed for real-time measurements where properties of fluids vary from time to time, . 

Density can also he detected indirectly through the measurement of some other process property: Measurement of boiling point elevation is one of the common methods of indirect density detection. Here resistance elements com¬pare the temperature of the boiling process sample with that of boiling water at the same pressure. The differential temperature scale for a particular 'solution can be calibrated in terms of density. This method is also used for end-point determination in evaporators.