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Posted on 25/08/10, under Aggregates & Mining, Application News, Bulk Solids Handling, Bulk Solids Measurement, Cement, Environment & Recycling, Exhibitions, Level Measurement, Nucleonics, Radar, VEGA Product News · RSS · No Comments
Non-Contact Level and Mass Flow Measurement and Control with Microwave and Radiometric based Instruments in Solids Handling – PART 1
Mr. Doug Anderson, Mr. Graeme Cross, Mr. Gary Baker
Abstract
Solids handling offers many challenges for measurement and control. The product properties are the most major – dust abrasion, impacts, bulk density, material flow and movement. These all have an impact on the type of handling equipment, as well as the measurement and control systems that say “when” and “how much”, no matter what parameter is being measured. Many measurement systems incorporate mechanical parts or movements, which require contact with the product or process. By using non-contact devices, the ease of implementation, and improvement to lifespan and reliability can outweigh any price difference, should there be one.
Introduction
This paper looks at 2 areas in particular, level and mass flow measurement, to explore the options for some applications, particularly for difficult to handle product or difficult to measure situations. These are not definitive for all applications, but some alternative ideas, with application examples, to show other ways these have been solved, to increase reliability and productivity, saving space and downtime for some difficult to measure areas.
Factors to consider for level measurement of solids
The product to be measured and the accuracy required, are the first considerations for a system.
A silo weighing system may be more suitable for the application, whenever it is practicable and affordable to use one, especially on a new installation, they are normally the first choice.
However this is not always suitable, and some of these considerations will also help decide. The elements to factor in for a measurement application is the type of vessel, what the surface area and profile is likely to be like for a representative level measurement, what the vessel is manufactured from, and the top and bottom forms, outlet and roof structures etc. These will have an affect on the performance of a measurement system.
Process conditions for measurement
If a vessel is to be measured, the filling stream and type has to be taken into account. Dust, air conveying, filling noise and turbulence will all play a role.
When the vessel is emptying, will there be bridging or rat-holing? If the vessel is ‘zeroed’ or ‘tared’ on a weigh cell system, because there is ‘nothing coming out’, what are the consequences if there are still tons of material inside? Temperature of the incoming product and pressure inside the vessel, particularly if it is high, also play a part.
Mechanical, product and safety
Mechanical forces exerted by the product, for example if a cable based level device is used and it is a mass flow silo, will there be a significant loading on the roof of the vessel, or will corrosion/abrasion cause wear to any devices in contact with the process. Could the product build-up significantly on the vessel or on the measurement probe. Finally there are the safety considerations, is ATEX for combustible dust and ignitable gases etc. required and what are the consequences should the vessel overfill?
PART 2 coming soon….
If you would like more information on the above blog please contact us on the details below.
Factors to consider for level measurement of solids
Posted on 13/08/10, under About VEGA, Aggregates & Mining, Bulk Solids Handling, Cement, Environment & Recycling, Exhibitions, Information, Instrument Ranges, Measurement Principles, VEGA Events · RSS · No Comments
Bulk Solids Europe 2010
International Conference on Storing, Handling and Transporting Bulk.
Posted on 09/08/10, under Application News, Information, Level Measurement, Pressure Measurement, Radar, VEGA Product News, Water and Waste, pressure · RSS · No Comments
Loch Level
SIL 2 has now become a requirement with loch level. The issue lies with the flood control gates for various lochs. If an obstruction sits underneath a sensor i.e. boat, canoeist it can make the PLC system think that there has been a sudden rise in the loch level. What VEGA offer are two devices that are SIL2 approved, the VEGAWELL pressure sensors and the non contact VEGAPULS 61 radar. The two inputs must see the level change before any flood gates are opened. For remote area, our new PLICSPLUS electronics only require 9.6 volts to power them so we can now use small wind turbines and link them with solar panels for the battery back up. Also, with the new GPRS electronics within our instruments you only need a data SIM card and we can transmit the signal to anywhere that has a mobile phone reception.
Typical installations on open water for level measurement of reservoirs, lochs, rivers and tide gauging
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Posted on 15/07/10, under About VEGA, Application News, Guided Microwave TDR, Level Measurement, Offshore Oil & Gas, Petrochemical, Radar, VEGA Product News · RSS · No Comments
Drilling Mud Level Measurement
The solution for drilling mud level measurement is easy for VEGA. We have sold many instruments for mud level measurement for onshore and offshore applications. Our solution will range from Guided Wave Radar technology to non contact radar. Most of the drilling mud’s are stored in storage vessels and are transferred into cyclones or similar type processes. We measure bentonite clays/muds to synthetic drilling fluids. Our radars are installed on the top of the vessels and ranged over the height of the vessel, this signal can be displayed remotely at the fill point by using a basic VEGADIS 61 display or you can take the 2 wire 4-20ma signal back to the DCS. The key point is that our instruments will work well even with the high pressures and steam produced within the process and product build up is not an issue with the guided wave radar solution.
If you would like more information on the above blog please contact us on the details below.
Posted on 09/07/10, under About VEGA, Application News, Applications, Guided Microwave TDR, Information, Level Interface, Level Measurement, Offshore Oil & Gas, VEGA Product News · RSS · No Comments
Condensate/Water Interface
VEGA have offered simple guided microwave radar level solutions for compressor knock out drums for various oil and gas platforms. The radar is installed in a suitable bridal for the 0-100 % range and can also have a magnetic indicator showing the level for dual redundancy systems. The temperature and pressures we would be looking at would be 80 degree and 85 bar, which is low as our radar range can reach up to 450 degrees and 450 bar! The issue with the knock out drums is that part of the process is condensate water that has a low dielectric value of about 1.6 and within the bottom of the bridal there could be water with a dielectric of 80. The radar will see the higher dielectric water at the bottom of the bridal and the magnetic level indicator will see the top level of the condensate water. So the solution ( if you cannot drain the water ) is to set the radar up for ‘1st large echo’ and change the Db threshold from 3 to 30. This will prevent the radar looking at any other products through the low dielectric condensate water. This easy parameter change is done by using Pactware software that can be downloaded free of charge from our website. This is a simple solution to a major process problem for offshore applications and by understanding the process we can offer reliable advice for critical applications that involve process trip faults.
If you would like more information on the above blog please contact us on the details below.
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