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Acoustic sensor monitors solids in pipes, filters

A Pulsar Process Measurement product story

Edited by the Engineeringtalk editorial team Dec 19, 2000

Using stress wave technology developed for non-destructive aerospace testing, the Pulsarguard acoustic sensor is ideally suited to the tricky problem of monitoring the flow of solids in pipes

In many process measuring applications, often the simpler the solution, the more effective the results.

Using stress wave technology originally developed for non-destructive testing in the aerospace industry, the Pulsarguard acoustic sensor from Pulsar Process Measurement provides the ideal low cost solution for monitoring a wide range of industrial processes.

The non-invasive, easy-to-fit Pulsarguard works by 'listening' to the sounds generated within a particular process caused by impacts, cavitation and friction.

It then differentiates between unwanted background noise and the narrow bands of useful noise information, to provide a unique acoustic profile of the process.

The sensor is ideally suited to the tricky problem of monitoring the flow of solids in pipes and ducts and, as a result, finds extensive application in pneumatic conveying systems both for alarm and on-going process monitoring.

By detecting small changes in solids flow pattern the Pulsarguard is very effective in monitoring the condition of filters.

The information from the sensor can be used to provide advance warning of blocking or clogging well before costly damage occurs while burst and damaged filters can be detected almost instantly.

In the food industry, the Pulsarguard can be used to detect blocked feeders, screens and pipes- a common occurrence where sticky or viscous products are involved.

The unit can also differentiate between the flow patterns of different grades of ingredients, such as flour, being conveyed to storage silos.

Sending a particular grade of flour to the wrong silo can cause product contamination, resulting in expensive material wastage and lost production.

Sensors fitted to the inlet pipe of each silo can quickly detect which grade of flour is being conveyed and trigger the supply to be switched off immediately contamination is detected.

It can also be used to alarm for the presence or absence of material in flight as well as monitoring the operation of fans,blowers and pumps.

The Pulsarguard has a wide range of uses in the cement and allied industries.

Fitting sensors to multiple kiln supply lines,for instance, can check for continual product feed for each and every material used in the combustion process.

The early detection of missing product optimizes kiln firing and minimizes the need for kiln shut down.

In ship cement off-loading systems, the Pulsarguard can play an important role in monitoring flow in the discharge lines preventing over pressure conditions in the receiving vessel when material flow has ceased.

The rugged acoustic sensor and built-in signal conditioning electronics are incorporated into a compact unit which is sensitive to process changes whilst ignoring audible noise and vibration.

The unit operates from a 24Vdc power supply and provides a 0 to 10Vdc coupled output.

Full sealing to IP68 is achieved by means of an all stainless steel construction and,as a result, the Pulsarguard is immune to electromagnetic interference.

This construction, together with the non- energy storing design, also means that the sensor can be used in hazardous areas, including Zones 0 and 20.

There is no doubt that the success of the Pulsarguard lies in its ease-of-use.

The unit is simply bolted to a predetermined point and because the sensor is completely non-invasive there is no need to shut down the process during installation.

Depending on what is being monitored, this may be adjacent to a pump or blower, or directly onto a process pipe flange as shown in the photograph.

Depending on the application, the Pulsarguard can be connected to an optional control unit with set points, PLC or chart recorder and can be used for short term profile monitoring or as part of a permanent control system.

Set-up and calibration is done on a case-by-case 'practical approach' basis depending on what the sensor will be monitoring, thus ensuring that the unit operates at optimum effectiveness.

The Pulsarguard is part of Pulsar's extensive range of level control and process monitoring equipment.