Complex automated systems are in demand in the field of measuring liquids. Engineers are pushing the boundaries to seek a more precise level of measurement & control system for liquids, due to the ever-more-stringent process control, and an inexorably strict condition of regulating the process. Advanced and enhanced accuracy of level measurement makes it possible to decrease complex process fluctuation, bringing about high-quality results, lesser costs, and even much lesser waste.
For measuring the level of liquids (heavy or light-weight) a few characteristics need to be considered. The damage caused by the improper selection of instruments can be of the same intensity even though the characteristics of liquids are more predictable than solids.
In the following sections, we shall walk you through some of the key factors that you should consider before you decide to measure levels in liquids.
● Types of Level Measurement/ Monitoring
One needs to understand the different kinds of methods that are available for level measurement/monitoring before they can choose the right one from an array of tools available.
- Gauges that help in the visual indication of the level.
- Switches are very helpful in the detection and control of levels, they are versatile, reliable, and robust in their function. These easy-to-install switches come in various sizes and make.
- On the other hand, transmitters are very useful for the continuous monitoring of the level in the tanks. The process application and functional requirement that is chosen, decide the type of instrument required. Remote programming is a viable option with a range of transmitters offering high temperature and pressure operations.
● Nature of Liquid
Some liquids are highly corrosive and can hence cause corrosion. In automation, process liquids can be both clean and clear or may have suspended particles as well. These liquids can even be corrosive, non-corrosive, hazardous, acids, alkalis, solvents, or expensive liquids, depending on their uses and properties. This makes the compatibility of materials used for the construction of a level measuring system important before dealing in liquids.
Properties of the liquid need to be pointed out to the engineers from whom you are planning to buy the level measuring instruments because it aids them to select an appropriate instrument.
● Properties of Liquid
Before deciding on the equipment, properties of liquids such as density (Kg/m3), viscosity (CPS), conductivity (us), or dielectric constant need to be studied and analyzed as they are responsible for the proper functioning and accuracy of the equipment. The temperature variations can cause changes in densities which makes it an important factor while selecting the equipment, and when density starts affecting the pressure it becomes even more challenging to measure the levels of liquids.
● Condition of Liquid
Condition of liquid means the activity of the liquid when in the tank that is foaming, fuming, boiling, or turbulent. Knowing the condition of liquid is vital as it helps in the selection of the accessories that are required to reduce the effect of agitation of liquid. Formations of vapors are a feature associated with most of the chemicals (especially, solvents and fuels). Vapors are the most common reason for incorrect readings as they can cause a problem with the functioning of the sensors and build pressure as well. There is a need to vent the tanks well before considering installing a level measuring unit.
● Operating Conditions
Considering these limits helps to select the equipment which will withstand them. Since level measuring instruments have minimum and maximum limits for temperature and pressure conditions parameters we must note the parameters to which the liquids are subjected, considering these limits will help select the equipment which will withstand them.
● Area Classification
The environment is also a very important contributing factor in the maintenance and functioning of the instruments. As per the statutory norms and industry standards, instrument manufacturers need to be briefed about the environment in which the equipment and the machinery are going to be set up. The environment where the liquids are handled could be hazardous, non-hazardous, or dusty. Having prior knowledge of these can help in choosing the appropriate instrument enclosure and weatherproofing (IP)/flameproofing that can function seamlessly in the respective environment.
● Sterile/Aseptic Process
To avoid contamination biotech and pharmaceutical processes have to be carried out under sterile conditions. These require a special type of process connections like tri-clover fittings to reduce the chances of contamination. Hence contact parts must have a mirror finish. Ultrasonic and radar level transmitters (that is the non-contact type instruments) are preferred for such applications. Moreover, these processes have high temperature and pressure conditions. Ultrasonic, guided-wave radar is among one of the more versatile technologies available.
If all of the above-mentioned factors are considered for level measurements in liquids, then you are good to go out to choose the appropriate equipment that can cater to your requirements in various processes.