Modern transfer chute design can utilize granular flow mechanics that simulates the flow of solids in particle form and the gas field that surrounds the ore particles.

Conveyor Dynamics, Inc. (CDI) has developed mathematical tools that can provide assessment of the gas turbulence and the airborne dust which can be generated based on the terminal velocity of all particle sizes when they exceed gravity's force. From this we can provide a retention time to decant the particle groups, dependent on the unsteady gas flow induced by particle motion, in all manner of chute designs.

Chute design has stepped beyond an art form and parameter guesswork. We practice dust control by knowing where to inhibit gas turbulence and eliminate dust leakage. It is not obvious. The form of the chute surfaces and stilling regions, within the chute, are necessary to achieve the ultimate goal of a dust-less transfer. Without knowing the gas dynamics, you are guessing. The gas dynamics are dependent on the particle dynamics. The particle dynamics are dependent on: chute shape, particle size distribution and shapes, chute surface frictions, particle surface friction, surface moisture, and so on.

We are happy to demostrate our methods. Compare our phyical modeling vs the meta-physical.

Lawrence Nordell

Conveyor Dynamics, Inc.

1111 West Holly St.

Bellingham, WA 98225

USA

website: www.conveyor-dynamics.com ■

I am pretty much interested in your Dustless Transfers chutes.

I am currently working in the industry where the dust problems becomes quite an issue. We handle different kind of material (lime stone - 30-80mm, basalt - 60-150 mm, coke 120-250 mm).

I would very much appreciate if you could send me some kind of brochure or catalogue of your chutes.

Best regards,

Janusz Tchorzewski

ul. Kwiatowa 14

66-131 Cigacice

Poland

janusz.tchorzewski@rockwool.com ■

Lawrence Nordell

We came to know that, you are supplying Dust less Chutes for Belt Conveyor Transfer Points. As we are in leaders of Indian Cement Industry, we hope your product is very useful to us. So, let we have your broucher / catalogue and product details for our records and consideration in various up-coming projects.

Early response in this regards is highly appreciated.

Regards

Regards,

Harihar Dora

ACC Limited

Project Engineering & Implementation Group

ACC Thane Complex, L. B. S. Marg,

Thane 400 604, INDIA

Phone: +91-22-25818038

Fax : +91-22-25824395

Email : harihar.dora@acclimited.com

www.acclimited.com ■

The logic of designing transfers that do not generate dust are described in detail in our book "The Transfer Chute Design Manual" in Chapter 9. (see www.conveyortransferdesign.com)

We have designed and successfully designed chutes that are relatively dust free for nearly 10 years now. In the book we describe a successful installation in an alumina plant.

Cheers

Colin Benjamin

Gulf Conveyor Systems P/L

For more information, please visit:

https://forum.bulk-online.com/showth...threadid=21089 ■

Here is an interesting read about some reputed experts fighting over the right to claim "Dustless Transfer"

Judgement in a USA court case removed a number of claims. See:

http://www.717madisonplace.com/wp-co...010/02/ccc.pdf

My posting this also poses a question of Patent Claims: even though the Patent is granted, it can be taken away. ■

In order to evaluate the level of dust emission measure in a ore transfer chute you must understand the gas, the rock flow and the geometry elements of the chute that controls solids and gas flows.

Many claim to have insight into ore and gas behavior. The proof is in understanding and predicting the flow based on known physics. Tests are conducted to quantify the rock and gas behavior. Some professionals resort to video imaging the rock flow and dust flow analysis by known and accepted particle size distribution, dust volume, and mass captured in the gas flow field.

I offer a set of images depicting rock flow and gas dynamics induced by rock flow. The gas velocity and regions of liberation of the dust in the rock flow associated with the gas velocity can then be determined.

Such as model can predict the gas volume and velocity leaving the exit points within the chute volume. Based on the gas velocity, known formulae predict the lifting of small dust particles and suspending them in the gas stream with sufficient time for the dust to be expelled from within the chute.

Without having reasonably accurate knowledge of the gas field, one cannot predict the behavior of dust emissions with accuracy unless experiments are conducted.

We believe these images are first time 3-D rock shaped granular stream, with induced gas flow, has been achieved. We wish to see if others have achieved the same.

Attachments

rock shaped granular dem particles discharging (DOC)

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I offer a typical problem facing the cement industry. How to identify and correct existing chute with improper dust control.

It is one thing to tell a client you can it. It another to tell that you can do it with all the physics to show the before and after results. Then back up the claim with guarantees and field measurements.

Photo:

Cement Plant Clinker Dust Liberation – Belt moves right to left

Notice Dual Pneumatic Dust Collectors – Not too Efficient – Note: forward stilling chamber

Conveyor Dynamics, Inc. (CDI) is providing a new chute system that will eliminate this problem. Our rock and gas model can predict the size and quantity of dust liberation. It can also predict the damage to chute liners, belt wear, belt tracking and belt loading configuration for maximum belt capacity. Note: we include the present dust collection negative pressures in our model to identify present extraction efficiency.

Why is it leaking, where is it leaking, and how much is leaking can all be answered with the new modeling techniques.

Attachments

nordell_transfer (JPG)

■

Sorry, did not include the example photo in last posting. Here it is.

Attachments

cement plant clinker dust liberation (DOC)

nordell_transfer (JPG)

■

Originally Posted by nordell

My posting this also poses a question of Patent Claims: even though the Patent is granted, it can be taken away.

Claims regarding Patents raise a number of questions that a blanket statement "has patented a new dustless transfer chute" do not address -

Is this a granted patent or an application?

In what country or countries has this patent been granted (or applied for)?

What are the claims made for the patent?

There can always be an application for revocation if there are grounds that the patent should not have been granted.

And if you have prior art, or details covered by the claims have been published prior to the application date, then there's not much value in the patent anyway.

A quick espacenet search has not shown any patents in the name of Gulf Conveyor Systems ?? Perhaps the patent number could be supplied so we can all read the claims? ■

Designer,

We also do not see patents in our search of Gulf or Mr. Colin Benjamin. The patents may exist. Best if Mr. Benjamin can present the evidence. Power to him if he has a claim or three.

We will see if he truly has demostratable performance improvements and what they are. Hopefully, he will not make us suffer with silence. He has shown great interest and expositories in promoting a book.

Did you read the court action I posted earlier? ■

Thank you for posting the judgement in this patent case. I have read it and the verdict was to be expected. Let me explain;

1) The original posting by Glenn Segars referred to a very successful dustless installation that Gulf did in the alumina industry. The claim that it was based on patented technology was totally erroneous. Gulf never did apply for a patent for this.

2) We were aware of the patent granted to Alan Weakley and always believed it was substantially based on prior art that he received gratis from Gulf and Prok. I was asked to be an expert witness for the defence but declined.

3) We refer to the patents in our book "The Transfer Chute Design Manual" and cover the design of dustless transfers from first principles. In the book we actually state that we do not believe that these patents had merit. Those parts of the patent that were deemed to have merit are not aspects we believe are required to achieve or design a dustless transfer.

In respect to designing transfers that minimise the generation of dust the principles are quite logical and easy to follow. It is well covered in the book and does not require any expensive software such as DEM to be used.

Trust this clears up the matter

Colin Benjamin

Gulf Conveyor Systems P/L ■

Originally Posted by Glenn Segers

Gulf conveyors has patented a new dustless transfer chute

This is a precise and unambiguous statement.

Searches by myself and Nordell have failed to locate a patent in the name of "Gulf Conveyors".

Now it turns out that the statement was untrue.

Sorry, but this casts a bit of a cloud over Gulf Conveyor Systems ■

Hi Designer or should I say Les,

It was never my claim nor my posting so I think your statement is a bit off. I was unaware that Glenn had made the posting and feel he may have been confused in that Gulf Holdings at the time were talking to those that claimed to hold a patent. This is the patent that Larry now refers to.

Cheers

Col Benjamin

Gulf Conveyor Systems P/L ■

I suddenly realise that the original post was dated September 2002.

Things move on in eight years!

PS, whatever makes you think my name is Les ■

Sorry,

Colin, you have been posting claims about dustless trasfers from your days learning from Tasma-Warajay (sic) prior to 1995.

Why did you allow an employee to post claims, in 2002 and you did not correct this erroneous fact until I post on dustless chute patent claims, in 2010? This falls a little below credible. Maybe, there was gold in them hills.

Your derision on DEM is also a little too self-serving. Since, I assume, you do not have analytic tools on gas dynamics prediction, why would you hang out a target with unfounded claims, dismissing DEM w/ Gas. "Read my book, all will be solved"?

Taking aim at your target, I challenge you to a duel of dustless. I will give you a GA of an existing chute that needs to be corrected to make it dustless. I will pay you, your fee (if reasonable), if you can meet or beat the CDI design claim for dust transport. Client will measure the result with well known dust analysis tools. Of course this means two chute inserts will need to be fabricated. I believe the client is willing to have such an evaluation where test result can be published.

On this subject, I am told, 20 km Curragh mid-drive chute, was modified by eliminating the hood & spoon, see below images. This has certainly made a lot more dust at mid-station drive. Why remove the curved hood and adjustable spoon? The client had a problem with the vibrating feeder that caused his surge problems at the mid station. LORA had a problem with the spoon drive that was fixable. Now we see high dust and much shorter belt life. Do you know who made these modification and why?

I post again referencing the dust generating transfer, modified from CDI dustless design type at 20 km Curragh mid-drive. The first two images ,rock and gas flow, are similar to Curragh after the hood and spoon were modified. The second two are similar to the original design intent minimizing high gas and dust flow exiting the skirts.

Attachments

chre_1_rock (JPG)

gas_sz0_06_2 (JPG)

chte_2_rock (JPG)

chte_2_gas_2 (JPG)

■

The last posting shows the concept of return gas flow illustrated in the second image. The large chute chamber does produce this effect.

The fourth image is quite different. The rock and gas is captured in a glove type configuration minimizing entry of gas into rock stream. The volume and velocity of the gas exiting the posted images gives rise on how the gas and dust might be quantified.

We have not shown the secondary dust control features that further reduce the gas velocity and dust emissions. Interested parties are welcome for discussion. ■

Hi Larry,

Pretty pictures do not create a design. I have many similar designs like what you depict that work, some do no not. Engineering starts with understanding the problem and going through a design process that develops a design that could work. Once you have a design then you can evaluate it using whatever process you want. If you like what DEM does for you, go with it. My point and you continue to avoid it is that DEM does not design the transfer, it only evaulates what has been designed. Our book walks you through the ACTUAL design process giving engineers a choice. Employ consultants like you and I that claim we are experts for a great deal of money or have a go themselves. We then give them some guides as how they can evaluate their designs including the use of DEM. Most transfers can be fixed by simply understanding the underlying design principles and this is where I am coming from. As to challenges and the like, these are all meaningless and a bit of grandstanding that takes the average FORUM user nowhere. You want to promote the use of your expertise and sell DEM programmes, I have co-written a book that I have some pride in. Lets leave it at that and lets those that buy and read the book be the eventual arbiters.

Cheers

Colin Benjamin



Gulf Conveyor Systems P/L ■

Hi Larry,

A short after thought, the book is a lot cheaper than my fees so rather than pay my costs as you offered, why not just buy a copy of the book and you will have the answer to your challenge.

Cheers again

Col Benjamin ■

Earlier, I stated I would leave this thread in peace.

Ill choice of words demonstrates intolerance, as you continue to sneer at DEM based technology. "Pretty pictures do not create a design." How trite, unbecoming or just ignorant.

Personally, I do not care if you never accept it. I believe the readers should know the "Best Available Technology" or in the patent fight Mr. Weakly-Wyoming labelled "BAT". It may or may not come from your book.

We too have designed hundreds of flow control chutes. We publish results with predictions and measured achievements: +20 times belt life wear reduction, elimination of belt punctures, high reduction in rock spillage, and vast improvement in belt cleaning, elimination of dust, et al. We have made comparisons with existing systems and improved systems using scientific dust measurement devices. We read the J&J, Tunra, Wollongong and other rheology reports, and we apply their findings. The key word here is we " publish" our methods and results.

Our methods come from substantial experience as well. We also see intuition is not always right.

I note, you have no interest in determining if there are better ways as the future unfolds. It’s a shame you wish to ignore the possibility "Best Available Technology" may go beyond your book. We are not a threat to you selling the book. We do not see the book as a threat to our business. I sincerely stated, I hope the industry is made better by your book.

No one is discrediting your book, your experience, or those of your colleagues.However, users should be aware that DEM rock flow (Newtonian and non-Newtonian physics) with 3-D gas dynamics, may produce a refined geometry, beyond common methods. DEM-Gas may show other beneficial results in combination with less discussed tuning methods to produce a superior result. Pretty pictures of true flow behavio is coming.

I assume we are both trying to:

a) minimize dust emissions

b) minimize belt wear

c) minimize spillage

d) minimize power to accelerate the product - how much saving can be achieved?

e) centralize the belt burden

f) maintain the highest high surcharge angle

g) minimize impact forces of the larger rock and tramp metal

h) minimize stream pressure that otherwise may lead to belt punctures.

All of these attributes can be quantified in the DEM code. Results will not necessarily come from CDI, but, from many who understand the importance of proper engineering metrics.

Let us see how the future unfolds. I too need say no more. ■

I will buy your book, if you guaranty we will find it insightful, rewarding, humours, and accurate, or our money back.

Do you agree to this deal? ■

Hi Larry,

At no stage have I nor will I sneer at DEM. I was looking at DEM before you if you recall many years ago. In an earlier email I also have said I continue to monitor and look at DEM and its advances BUT I also believe it still has serious limitations in some applications and have enough evidence to back up my claims (not published in the book). It also does not change what I have said and continue to say, it is a design aid, not a tool as DEM cannot develop a design, that has to be put into the model by the designer. Sure if you have done enough designs you could use a design library to see how an old design would look under different circumstances but DEM requires designs to be inputted. As with other methodolgies you can use such an aid to fine tune designs and that is the purpose of such aids. Better to evaluate as best you can before you build.

The outcome logic both of us try to achieve in any design of a transfer that minimses dust generation is as you say identical. Our methodologies appear to be very different. The book is about design starting from first principles. It does go into a lot of detail but most importantly while it looks at design aids, the way they work and their attributes it does not dwell on them. It is much more focussed on the design process. As for the book offer you made I cannot offer to you what I do not offer to others. There are no returns. If you want to take me up more directly on this particular subject email me direct.

Cheers

Colin Benjamin

Gulf Conveyor Systems P/L ■

Colin,

Your memory is fading faster than mine. We came together when you told me about your interest in Paul Cleary's DEM work at CSIRO, in late 1994 or early 1995.

I am puzzled at how you can be fully informed on the advancements of DEM, when you are very occupied writing. DEM is being studied by hundreds of researches in most major university in all advanced and developing countries of the world. Its power will exceed FEA. It is FEA's mathematical superset. Where do you obtain your technical insight?

I do understand your claim that DEM is not a design tool. I do not agree. Just as with starting any design venture, there are apriori details. These are axioms of design. They are simple to verbalize. They are another stretch to put into practice. We know these axioms and practice them. Axiom do not design, they are the first step such as, what slope, what shape - Bernoulli (brachistochrone problem) perhaps, or not. There are too many other factors that DEM enlightens for us.

We engaged CSIRO, in 1995, and jointly concluded that CDI was about 5 years ahead of CSIRO, at that time, based on their planned progress. CSIRO-CDI made plans for a privatized joint venture, which incorporate the best advancements of both companies. Most of the DEM technology came from CDI. Paul validated our methods together with our fluid dynamics integration during a CSIRO visit to our Bellingham office.

Analytic trials were given by the Rio Tinto Perth Reseach Center (ATD), to validate the solid-fluid-gas codes. Remeber where Mr. Donecker collected his lab equipment from.

CSIRO's applied mechanics researchers visited our office in Bellingham and met our team of 4 PhD's. A strategy was set to jointly market a new DEM-GAS code called ROCKY.

About 2 years later, we abandoned the joint venture, which is another story.

CDI kept the concepts, we further developed a new ROCKY, The new ROCKY has many more advanced features, beyond any DEM code on the market today.

Enough. ■

Hi Larry,

One thing you never stop doing in this industry is learning and while I may not have committed the energy you have into DEM, I am aware of its capabilities as I not only see the end result but researchers and others are very quick to want to keep people like me abreast with it's capabilities. I am fascinated as to how you can claim DEM is a design tool when it is a modelling programme but that is another story as you say. We will continue to come from different directions and I guess have many more disagreements on matters of design going forward, this issue being on of them.

All the best

Col Benjamin



Gulf Conveyor Systems P/L ■