Belt Weighers For Stacker Reclaimer Application
Dear Sir,
What is your experience of installing belt weighers on booms of stacker / reclaimer.Has your company ever supplied belt weighers for such application, is there a special software or system required for the belt weighers? ■
Weighing On Stacker Reclaimers
Dear P.J.Talreja,
I have been involved in supplying belt weighing equipment on stacker reclaimer booms. If the boom is fixed at a set elevation then there generally is little problem. If the stacker uses a variable angle luffing conveyor then the calibration will shift depending on the angle of the conveyor. As both the zero and span calibration points change, it is a very complex problem to solve.
We have in the past supplied angle compensation units but I have very little confidence in them.
We would usually recommend that the belt weigher is installed further back in the conveyor system from the boom conveyor. I can understand that this could be a problem if you are using the information from the belt weigher to control the stacking and reclaiming but if the weigher is being used for control purposes only then probably a 5% error is acceptable. We would in this instance set the conveyor at its mid point angle and calibrate at this point with material. The error caused by any angle change is roughly proportional to the Cosine of the angle of the conveyor away from its original calibration point.
If you want accurate and repeatable results then don't weigh on a variable angle conveyor.
Problems can also be encountered when the boom moves and the effective length of the conveyor with material present changes. The weigher should be at least 20 idler sets away from the worst case position and even so the tension change will probably still produce errors.
Regards
Jon Scarrott ■
Re: Belt Weigher Guide
Dear Mr Scarrott ,
Thank you very much for guidance. Our experience has also not been too good as far as the belt weigher performance are concerened on conveyors not meeting all the requirements. I espescially had a doubt on belt weighers for stacker which now stands clarified. I have also sent tou a mail seperately for the free guide on belt weighers.
Thank you,
Best Regards, ■
Angle Compensation
This discussion addresses an important, often overlooked, issue.
Our company developed an Automatic Angle Compensator many years ago. This device eliminates the effect of a change in the angle of elevation of the conveyor and is available for around $400 USD.
You are not alone in your distrust of Angle Compensating devices. The older technology had a slightly higher failure rate than other scale components.
Angle Compensation was originally developed for use on stackers. The analog version was simply a potentiometer with pendelum. When the elevation of the conveyor changed, the pendelum turned the pot to increase signal from the scale (commensurate with the increase in conveyor angle). When the angle decreased, the signal was proportionally decreased. These Angle Sensors did function properly, but had a tendency to fail after a few years (the pot wore out simply wore out). When this occurred, scale performance became unpredictable; depending on when the angle sensor decided to short out.
The new generation of Automatic Angle Compensators are digital, and sense G-force changes in multiple directions simulaneously. Durability is greatly enhanced. There are no moving parts. They are now widely used on stackers and high vibration applications, i.e. portable crushing and screening equipment, with very good results. ■
Belt Weiger
where from i can have the basic knowldge of belt weigher and solid flowmeter how to select and design data
prdp.ks@sify.com ■
Re: Belt Weigher Guide
Contact you local Schenck Process representative who will be able to help you select the most suitable weigher for your application.
www.schenckprocess.com ■
Belt Weigher Guide
I have emailed you the Lodestone Belt Weigher Guide
Hope this helps
Regards
Jon Scarrott ■
Angle Compensation
Your device looks very interesting. As you say the older versions just wore out and the belt weigher was then blamed for giving bad results.
Do you have a data sheet that you could send me?
regards
Jon Scarrott
Lodestone Electronics ■
Belt Weigher Guide
The Lodestone Belt Weigher Guide is now available in pdf format. It gives details of all the good and bad aspects of installing a belt weigher and how to get the best out of your weighing equipment.
If you would like a free copy of this guide please email Lodestone Electronics Ltd at sales@lodestone-electronics.com.
Jon Scarrott
www.lodestone-electronics.com ■