Introducing new technology to the market is never an easy task, but laser technology developed for the process control industry has proved very successful, both locally and internationally. Laser has now become synonymous with ultrasonic and radar for distance measurement applications. The local company, Laser Measurement, develops and manufactures laser equipment for noncontact distance measurement for various industrial industries, including mining.
The instruments, lasermeters, have been successfully installed in various applications where they are used for level control in bins and silos, and for positioning applications of heavy machinery. The reason why laser is chosen is that it can cope with the dust and vibration present in these applications. The operating range of these meters varies from a short 20 m to as long as 350 m. Tests are being done to expand the current range up to 500 m.
Newco Instruments, the sole agent for LaserM's products in the Vaal Triangle, Gauteng and Mpumalanga, has installed lasers with confidence in the iron, steel and metal industries. "Laser technology has a substantial advantage over other technologies used for level control and positioning applications. Its narrow, parallel beam allows for measurement over vast distances, with no interference from unwanted signals. Travelling at the speed of light, a rapid response from the signal controls processes with greater efficiency," states Jaco van der Linde, MD of Newco Instruments. One of Newco Instruments' main clients in the Vaal Triangle has several lasers currently operating, mainly in anti-crane collision and tippler railcar positioning applications.
In above applications, the lasermeters are mounted in the open, either fixed to a tippler railcar or from the point from where it is being measured from using a reflector plate to increase signal strength. The tippler railcar is positioned over four to eight bins, where the laser is used to position the car so that the material is dumped into the correct bin, with no contamination in neighbouring bins. In this particular application the meters have been working successfully for four years.
At another very successful application site Newco Instruments has used the lasermeter LM4 to position a scrap car over a 40 m range. The lasermeter is fixed to the side of the scrap car. The scrap car 'collects' dumping material from a crane then moves to the furnace where the material is dumped.
Laser Measurements' international partner, K-Tek Corporation, also uses these lasermeters in the same type of applications in the USA and other countries. In one installation there are silos 18 m high, where several conveyors and trippers load each silo independently but simultaneously.
Problems associated with this particular application are:
* Several silos are being filled and emptied at the same time.
* Materials with small particle size create dust.
* Extreme peaking and slumping.
* Products' colours vary.
* Dielectrics vary greatly.
* High vibration when the silos are turned on.
In this particular application, all the competitive instruments like radar and ultrasonic have been tried, but without any success. Reasons for failure has been cited as the moving locations of rat holes, worn through sensor cables, changing dielectrics due to different materials, moisture changes and uneven coatings. The short range of this particular application makes the LMO2 the instrument of choice
New software in the lasermeters, due for release soon, is the C+ version with enhanced dust penetration capabilities. This is currently being tested at application sites locally and internationally with encouraging results. Laser Measurements' company policy of 'think laser' is used to focus the industry to the benefits of laser technology and to view laser as the superior technology for level control in many process control systems.
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