Why level measurement ? : Week 3/15/2012

In the last article, we discussed about whether it is possible to both measure & improve the FAD. In this article, we will discuss about Level measurement

Why level measurement?

Measurement of level in variety of vessels used in industry is important. There can be valuable liquids, hazardous liquids or important liquids that need to be stored carefully. Wrong or inaccurate level measurements can result in real levels in vessels being excessively higher or lower than their measured values. While low levels can cause pumping problems, high levels can cause vessels to overflow. This may cause safety and environmental problems. If the vessels are operating at wrong intermediate levels, it can result in poor operating conditions and also result in wrong accounting of material.

The level of a liquid in a vessel can be measured directly or inferentially. Examples of direct level measurement include float, magnetostrictive, retracting, capacitance, radar, ultrasonic and laser level measurement technologies. Weight and differential pressure technology measure level inferentially. All have problems that can potentially affect the level measurement.

Types of Level Measurement

Direct Measurements :

  • Radar
  • Guided radar
  • Electromechanical
  • Ultrasonic
  • Laser
  • Capacitance

Inferential Measurements :
  • Hydrostatic pressure
  • Differential pressure
  • Weight

What is so great about Radar?

The most important thing about radar technology is that it does not make any contact with the liquid or solid material in the vessel. Radar measurements are not influenced by airspace conditions like humidity, heavy vapors, and vapor layer stratification due to temperature fluctuations. It works well with heavy dust in the measurement area.

You can use non-contact radar gauges for tank and vessel level measurement on almost any liquid and many solids. It can be used in storage condition or during processing. It is versatile because it is not affected by changes in product or process in connection with temperature, pressure, density, conductivity, vapors, or dust. Since the measurements are done without contacting the measured liquid or solid, it makes them versatile and reliable. 

When it comes to Liquid Level Measurement....

Traditionally DP type /Capacitance type level transmitters were the only most common solutions for liquid level measurement. However, today it is possible to get the latest technology of guided wave radar at similar prices, it become more advantageous to go for the guided wave radar technology.

Usually, DP type transmitters are associated with issues related to frequent maintenance, accuracy & high dependability on many components. All these issues can be overcome with the use of guided wave radar technology
When it comes to Solid Level Measurement....

In high bins and silos, sensors with cables may suffer mechanical wear, or by mechanical load and adhesion of the product. This can reduce the lifetime of "contact" sensors and increase user’s maintenance and servicing cost. Non-contact Radar Level Transmitters don’t have these problems. They are easy to install and configure. This means :
Saving in maintenance costs
Savin in service costs
Increase in the lifetime of your sensors
Reliable measuring results
Safer processes

In our next article, we will discuss about some applications for guided level radar technology.