26

Jan

2015

Reliability and Accuracy for Chemical Tanks

Published on Monday, January 26, 2015

 

Chemical tanks showing the installation of Pulsar equipment

Summary - Level Star 110 (now incorporated into the Ultra Controller Range) non-contacting ultrasonic level measurement was supplied to a major chemical manufacturer, resolving a problem that had in effective gauging of Sodium Hydroxide. The Pulsar equipment replaced ultrasonic equipment previously supplied by a different manufacturer which had not dealt with the multiple echoes from the dome top of the tank.

Equipment used:

The tanks within the application (see pictured) were 3.6 metres high, with a deep domed top. The ultrasonic equipment that had been previously in place was failing because of the multiple echoes created by the ultrasonic pulse bouncing around the inside of the vessel. Multiple echoes can be a problem, especially when considering relatively short shot applications on liquids. In this type of application, the multiple echoes were almost as significant as the "true" echo and can swamp the transducer. The echo-processing software can have difficulty in discriminating the correct echo from the mass of competing signals.

dB6 Flanged TransducerPulsar non-contacting ultrasonic instruments have the advantage of DATEM echo processing software, which leads the world in terms of sophistication. DATEM is able to pick out the correct echo among all the competing "noise" and, once identified, will maintain its contact, following it as the level rises and falls. On rare occasions, even DATEM will not pick out the correct echo automatically. In these cases, it is a simple matter to identify the correct level, after which DATEM will take over and continue to follow the correct echo against all competing signals. In this application, Pulsar supplied Level Star controllers (now Ultra controllers), mounted locally to the tanks to provide local display for the plant operators.

The tanks are cylindrical and the Level Star (now Ultra) uses the measurement of liquid level to automatically calculate the volume present in the tank. In addition, the Level Star provides both high and low level alarms to warn staff of potential problems and to identify re-order points.

The transducers used were flanged dB6, with a PTFE face to protect the transducer from the caustic chemicals.

The Level Stars (now Ultra) and transducers were easy to install and simple to set-up, and using Pulsar's unique menu-driven set-up routines, installation was completed in only a couple of hours. The correct level was accurately identified straight away by the equipment, which has provided accurate measurement now for an extended period, proving that Pulsar equipment has the staying power for tough applications.

From the Pulsar Archives - March 2005

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