Density is defined as mass per unit volume. The relative density is a unitless quantity equal to the ratio of the density of matter to the density of water at standard temperature. In fact, density indicates how dense the mass of matter is. For example, lead is a dense substance because a large amount of it is concentrated in a smaller volume on the other hand, the density of air experiments is very low.
Measuring and controlling fluid density can be important and vital in industrial processes. Density measurements provide useful information about compounds, chemical concentrations or suspended solids in a liquid.
Density is measured in similar ways to surface measurement methods. Some of the density measurement methods are:
• Differential Pressure
Mass flow meters are also able to measure density. The following describes the density measurement methods.
The basis of this type of measurement is based on the constant height of the liquid and the differential pressure measurement. Since it is possible to change the level, the performance is based on the pressure difference between two specific points. Because the height between two points does not change, any change in pressure is due to a change in density. The distance between the points is equal to the difference in liquid pressure between the two heights.
Density measurement using radiation is based on the greater absorption of gamma rays by increasing the relative density of the material. The main elements of such a system include a fixed gamma source (usually radium) and a detector. Here the detector converts changes in the intensity of the rays received from a constant volume of liquid into an electrical signal. This type of measurement is often used in rubbing. Where the density of the sludge determines the effectiveness of the reservoir sludge.
The attenuation of a vibrating object in a fluid increases with increasing fluid density. The vibrating object is vibrated by an external energy source and can be a reed or a submerged plate.
Density can be measured in one of two ways:
1. Change in the natural frequency of the vibration when the vibrating object is energetically constant.
2. Change in the strength and magnitude of the vibration when the vibrating object is periodically hit (such as a bell).
Fixed surface overflow tanks are the easiest way to measure density because only one differential pressure transmitter is needed. This method is similar to the hydrostatic pressure measurement method, except that the measured density is related to the distance between the dry and wet bases (H). In this case, it does not matter how much the fluid level changes and only the liquid level should be higher than the connection point of the wet base to the tank. However, applications with variable surface or static pressure require estimation.
Effects of temperature on density
An increase in temperature causes the liquids to expand, resulting in a change in density. Not all liquids expand at the same rate. To ensure the accuracy of the measurement, the relative density measurement must be corrected based on the effects of temperature, although this is not practically the case in many cases.
In applications where accurate measurement of relative density is crucial, the temperature may be controlled for a constant volume. Of course, it is possible to make the necessary corrections for small temperature changes in calibration of precision density instruments.