Using laser technology for level measurement in process control

May 2002 Level Measurement & Control

Laser instruments used for level control in process measurement use a semiconductor laser, which has the ability to flash on and off very rapidly. It measures distance by timing how long it takes a pulse of laser light to travel from the laser instrument to the object directly ahead and back again.

One of the main characteristics that gives laser its unique level measuring ability is based on the fact that it has a very short wavelength (compared to ultrasound and microwave radiation). This means that the beam of light emitted can be focused so that there is virtually no beam divergence. The laser can then be focused on an object without any interference from surrounding objects.

Another characteristic that plays a major role in lasers measuring ability stems from the fact that the laser radiation propagates through the medium at the speed of light. This means that very high update rates are achievable, with none of the 'lock-in' problems that can be experienced when using ultrasonic instruments. With laser instruments, the measurement is not at all dependent on the pressure or temperature of the medium, as the speed of light remains relatively unchanged through any gaseous medium. In applications, such as petrol or gas tanks where the density of the gaseous medium is unknown (and continually changing) laser instruments will give an accurate measurement without any calibration problems.

"Compared to other methods of level measurement laser is technologically much more advanced. It is faster, more accurate and easier to use than ultrasonic, radar, nuclear or mechanical methods. It appears that it will become the favoured method of level sensing as soon as it becomes price competitive with other existing technologies," concludes LaserM.

LaserM

011 314 4130

[email protected]

Further reading:

Small, inexpensive radar level transmitters
VEGA Controls SA Level Measurement & Control
Anyone who needs to keep processes running needs level measurement technology that measures reliably. However, what is needed is not always the most ‘fully featured’ solution, but the smartest one. This is exactly what VEGAPULS radar transmitters of the BASIC series do.

Read more...

---

Meeting the challenges of tank obstructions interfering with radar
Level Measurement & Control
One of the most challenging applications for non-contacting radar level transmitters is measuring level in tanks with internal obstructions, such as agitators, heating coils, pipes, ladders or baffles. Rosemount non-contacting radar level transmitters from Emerson feature an advanced solution that enables accurate and reliable level measurements in tanks with obstructions.

Read more...

---

A fresh approach to dairy processing
VEGA Controls SA Level Measurement & Control
Ensuring the quality and safety of milk throughout the production process is of the utmost importance in the dairy industry. The VEGABAR pressure transmitters are suitable for hygienic applications. They are an asset in the dairy industry and have been used with success for measuring the milk level and the process pressure in storage tanks.

Read more...

---

Multiphase level measurement
Mecosa Level Measurement & Control
The measurement of more than two phases or of interfaces that are not clearly defined poses a number of challenges for measurement technology. Radiation-based measuring systems such as Berthold‘s EmulsionSENS master these problems.

Read more...

---

Simple and efficient level measurement in the mining, minerals and metals industries
Endress+Hauser South Africa Editor's Choice Level Measurement & Control
Measuring devices in the mining, minerals and metals industries face the challenge of varying material states and long distances in measurement height. Endress+Hauser’s answer to these challenges is the new Micropilot family.

Read more...

---

Level measurement of an acid dosing tank at a WWTP
Level Measurement & Control
Ferric chloride and other acids are essential chemical substances in water and wastewater treatment. To control the dosing of acid solutions, an Australian wastewater treatment plant uses a special container to store, mix and add these chemicals. The company opted in favour of KROHNE’s OPTIWAVE 1540 radar level transmitter

Read more...

---

Powering sub-Saharan Africa’s energy future
VEGA Controls SA Level Measurement & Control
Crude oil storage plays an important role in the energy infrastructure of sub-Saharan Africa. The management of crude oil storage in comes with numerous challenges, including safety concerns, environmental conditions and infrastructural limitations.

Read more...

---

A new era in radiometric level and density measurement
Mecosa Level Measurement & Control
The LoopSeries LB 430 radiometric detector from Berthold Technologies has a revolutionary power solution and sets new standards in level and density measurement.

Read more...

---

Level measurement of leachate from sewage sludge humification
KROHNE Level Measurement & Control
A municipal utility in eastern Germany operates a state-of-the-art wastewater treatment plant with sustainable sludge treatment. The ultrasonic signal was being partially deflected by the wind, leading to frequent false measurements and inefficient process workflows. The problem was solved by replaced the ultrasonic level sensor with KROHNE’s OPTIWAVE 1540 non-contact radar.

Read more...

---

Groundbreaking measurement system
Mecosa Level Measurement & Control
Berthold Technologies has launched the LoopSeries LB 430, an innovative, industry-leading measurement system designed to enhance operational efficiency with advanced level, density, and level switch capabilities.

Read more...

---