Dear Andrs M,

Although the basic technology is simple, pneumatic conveying calculations must describe a complex set of interactions between many parameters.

A complicating factor is the compressibility of the conveying gas.

The many universities and companies, who are active in the research and manufacturing of pneumatic conveying installations have developed ways of estimating and calculating those installations by measurements on test rigs with scaling factors and databases of built installations as references for future installations.

By discovering trends in the influence of changed parameters on the pneumatic conveying performance, a number of quasi- formulas are generated and applied.

And this for many materials, pressures, velocities, loading ratios, installations with various horizontal and vertical pipe lengths and number of bends.

Especially the companies have kept the knowledge (whether experience or calculation methods) for themselves for commercial reasons.

For more information I recommend (my own) article in the BULKBLOG:

Pneumatic conveying, Performance and Calculations:

https://news.bulk-online.com/?p=65

Dense phase- or dilute phase pneumatic conveying:

https://news.bulk-online.com/?p=238

Pneumatic conveying, turbo- or positive displacement air mover:

https://news.bulk-online.com/?p=309

Energy consumption per ton of a pneumatic conveying system:

https://news.bulk-online.com/?p=331

Pneumatic conveying, an unexpected relationship.

https://news.bulk-online.com/?p=445

Pneumatic unloaders: Problems to avoid

https://news.bulk-online.com/?p=74

Influence of electro static charge on pneumatic conveying.

https://news.bulk-online.com/?author=15

Have a very nice day

Teus ■

Andres,

Another software program you can get is Pneucalc. It is from Pneumatic Conveying Consultants.

But if you know EXcel you can easily use my article "Theory and Design of Dilute Phase Pneumatic Conveying Systems" to run your calculations.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Dear Andrs M.

Even when someone has a pneumatic conveying program that is based on physics (not on trends) and works, I seriously doubt that without extensive practical experience this program would be of almost no value to the user.

It would help to build an understanding of the technology though.

Interpreting the calculation results, whether they possibly will be matching the real world, without field references is very tricky.

Nevertheless, many pneumatic conveying installations are built and work.

How these installations are calculated (or guessed) or based on previous installations is always kept hidden from the users and the public.

Articles about this subject never reach a level where the conclusions lead to a direct applicable knowledge or method.

In the land of blind, one eye is king.

Have a nice day

Teus ■

Over the years I have seen a number of programs by a number of companies for pneumatic conveying systems. Most of the reputable companies have some sort of programme / spreadsheet normally developed in house, which I must admit people guard it with there life. I have accumulated a number of such programs over the years some are so old they run in DOS. Latest ones are vista compatible! So for average man looking for these programs will not find many commercially available PC software as pointed in this thread.

Lean phase system design is the easy one; companies with test plants calculate the friction factors for different materials and develop a program very similar to Mr Amrit paper. Since it is not always possible to test all the materials once a comprehensive database for materials is developed the new materials are related to this database on bulk density, particle size, shape etc. This is where experience comes in and I will totally agree with Mr Teus “In the land of blind. One eye is the king”

Dense phase program is slightly different and requires conveying characteristic curves developed for every material. These curves normally will have information like distance vs pressure drop at different conveying rates. Pick up and exit velocities, Max SLR etc etc. This requires extensive testing in test plants. Since it is not an easy task we don't see many people selling dense phase systems. But again some companies with test plants do a trial on the material and design the system on scaling. ■

Dear Mantoo,

Do you have an idea of the consistency of the programs, which you have collected?

Are they based on the same mathematical approach?

Do they use the same velocities for the same material?

The same capacity-pressure curves?

Are the programs consistent in respect to the results when off standard installations are calculated? (F.i. at extreme velocities or pressures).

How is the reliability of the various programs when it comes to built installations?

Sometimes, I have the feeling that some people guard a program with their life, where there is no real program. And that is exactly what they want to hide.

I remember that a failed commission capacity test was corrected by the argument that the tested capacity was below the contract capacity, because the tested grain had a bulk density of 720 kg/m3 instead of the contractual 750 kg/m3.

By multiplying the tested capacity by the factor 750/720 brought the tested capacity within the required value range.

As if the capacity of a pneumatic unloader was proportional to the material bulk density!

The company, I just started working for at the time, had accepted this misleading argument for many earlier units.

Maybe, this lack of consistency in the description of pneumatic conveying is the core of the many questions of engineers, searching for a clue.

Have a nice day

Teus ■

Somehow or other we all have to make money to survive, it's just a case of how you do it. You can design/make/supply hardware or you can write software, it's a matter of what you choose.

If you choose to write software what are you going to write to make money? The high volume software is operating systems and standard 'office' software, but these are largely sewn up these days. You could write specialist software like something to design pneumatic conveying systems. But how long would it take and what's the market? How many would you sell, it's not a mass market, established system designers will probably have their own in house solutions so you're left with start up companies. You'd probably have to pitch the price quite high to cover the time you spent writing it which will suppress sales. If it's good it will probably be hacked and posted on a download site which will suppress sales even more. Not all countries have a good record recognising intellectual property rights.

So maybe that's why there aren't many programmes to design pneumatic conveying systems, too much work for too little return. Spend your time making money elsewhere. ■

Yes supply and demand / intellectual property rights are a good reasons.

But there is also a legal aspect of it. If you sell a software and someone sizes a system on it and it doesn't work then ? Who's liability is it....if you sell it with a disclaimer then what confidence the user will have in it.

Then again lot of people can put a rotary valve and roots blower to somewhat reasonable levels. The more challenging bit is the dense phase conveying keeping the screw pump out, the blow tank, air manifold design and operating sequence probably are equally important as the material conveying properties.......... ■

Dear designer,

I believe that your conclusion is very true.

It describes the dilemma, whether to publish or not.

As long as the software is propriety of one party it is possible to make your living with the exclusive knowledge.

The most lucrative way of making money for others is being a free rider and as you say, leave you with no return for your efforts.

However, there is also such a thing as intellectual pleasure in the technology and in intellectual achievements.

I used this attitude to fulfill a job and made a living out of it and enjoyed doing that.

If there are not many programs to design pneumatic conveying systems, that also indicates that the hacking and leaking (F.i. by redundant employees) is not effective.

Assuming that there are chasers on the market, why don’t they catch anything?

Cheers

Teus ■

Originally Posted by Teus Tuinenburg

However, there is also such a thing as intellectual pleasure in the technology and in intellectual achievements.

Intellectual pleasure (like being able to do The Times crossword), but this alone doesn't put food on the table....... ■

Dear designer,

For me, it worked the other way around.

My job(s) were to design and build pneumatic unloaders and to do that, I had to develop the knowledge on my own steam. Getting the knowledge of the shelf or have it explained by an expert was not an option.

And I always enjoyed it and I still do.

The food on the table made me develop the knowledge.

Mr Andrs seems to find himself in the same position and therefore started this thread.

I hate crosswords, because after success you throw them away.

Cheer up

Teus ■

Gents,

In my opinion the main problem is that there is a big gap in teaching the subject of solids handling in our colleges and universities. Pneumatic conveying is a part of solids handling and except for two or three universities it is not taught by any one else. This is the main reason that we do not have more, commercially available, pneumatic conveying calculation programs.

Those programs that are available do not explain the theory and the basis that were used in their programs, thus rendering their programs a black box.

This is why there is so much cynicism being expressed above.

I attempted to open this black box through my article on dilute phase design and technology. This article gives a proven method for dilute phase conveying system design. Solids friction factor is the only term that has to be determined.

This article can easily become a basis for a computer program.

I hope I will be able to write a similar article on dense phase design in the near future.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting ■

Originally Posted by Amrit Agarwal

In my opinion the main problem is that there is a big gap in teaching the subject of solids handling in our colleges and universities.

This is a true statement. There are universities across the world who are involved with bulk materials handling, but the number is limited. (It's a dirty messy business bulk material handling, without the glamour of the new technologies). However, my experience is that pneumatic conveying, together with flow from hoppers, tend to be the primary area of R&D possibly because it's easy to accommodate lengths of relatively small bore piping circulating around a university laboratory. ■

Dear designer, Mr. Agarwal, Mantoo,

Now that we know the reasons for the absence of working pneumatic conveying software, what should be done to improve this situation?

Andrs (and probably many others) is still facing his problem.

Mr. Agarwal used the qualification “black box”.

However, “black boxes” can reveal their content by correlating the input and the output.

F.i. by plotting the capacity against a range of K factors and check the reliability when extremes are used as input, s.a. K=0.

Or solving the program for a range of capacities against conveying pressure. This should give the air only pressure drop for the installation at a capacity=0.

The ultimate check is to calculate a Zenz diagram

Also comparing the various software for consistency is a way to discover the underlying theories.

I am convinced that you will find alarming results.

Back to the problem of knowledge sharing.

A possible solution could be a PhD candidate, who develops the theory into mathematical equations and a computing algorithm. During his promotion research, he should also work as an installation builder, operator and trouble shooter. Especially, the trouble shooting function will reveal a lot of information on the subject of detailed phenomena.

His thesis should be published afterwards, which brings us back to the considerations of designer and Mantoo.

Quotes

Designer:

how long would it take and what's the market?

established system designers will probably have their own in house solutions so you're left with startup companies.

Not all countries have a good record recognizing intellectual property rights.

too much work for too little return.

Mantoo:

Most of the reputable companies have some sort of program / spreadsheet normally developed in house, which I must admit people guard it with their life.

companies with test plants do a trial on the material and design the system on scaling

Unquote

Referring to the market, I would say that the pneumatic conveying market is rather big, in bulk conveying as well in other industrial sectors. (The threads in this forum prove that).

Referring to guarding knowledge (or non knowledge) with their life even exists among colleagues in the same company. (employees politics is a Walhalla for managers)

It seems that there is a world to win, but nobody wants or gets the chance to do it.

Keep up the spirit

Teus ■

Being from academic background I can say with confidence that Pneumatic conveying field is a very well researched area. I have seen research papers on this subject form 1920's and a very steady stream of research form 1940's to date. There has been significant research carried out in Universities in USA, UK, Germany, Norway, Australia, Japan and South Africa over the past few decades. More recently some research work is coming from research groups in Singapore, China and India.

In my opinion there is no lack of information on this subject it is a very well researched and understood. If required there are enough models already available to develop a software. It boils down to who should do it and why ? Thousands of research papers are available on line and all the Ph.D. thesis are available in the central libraries and anyone can access them. There are some books also available the oldest one I can remember on multi phase flow was by “Boothroyd” published in 60's.

Looking form commercial aspect, if I was buying an expensive conveying system I would like to see a reference list and maybe a site visit to see a similar system running. So if any one wants to use a software to start a business it will be a difficult task (but is doable).

Most of the requests we get here on this forum are about non- performing systems as this filed is plagued with them. (I will not go into the debate why why don't perform). Mostly the requests come from plant engineers who just want to make these system work and are not normally interested in understanding pneumatic conveying. For them a troubleshooting guide will be very beneficial.

I like the term “Black Box” to me it just means “I know some thing you don't”.It is people with experience and knowledge in this field tell others that it is a back box but actually it is not. It is very well researched and well documented field only problem is there are very few people who have this knowledge and experience. ■

Dear Mantoo,

Although ,being from a practical background, I agree that pneumatic conveying is very well researched around the world. Indeed this research has generated many reports, articles, opinions, simulations and recommendations for further investigations.

However, the academic approach still has to be translated to a practical way of designing and trouble shooting.

The thousands of research papers, which are available on line and all the Ph.D. thesis do seldom share a common view on how to approach a calculation model.

The common character of the published knowledge do share the mathematical skill of the authors.

When I read the articles, I mostly end up with the remark: OK, interesting and now what?

Sometimes I discover an eye-opener that helps me further or confirms a previous assumption.

If you want to buy a pneumatic conveying system by reference and visits to similar installations is OK, but not a scientific approach. It does not work when you want to have an off standard installation.

Plant engineers who are not normally interested in understanding pneumatic conveying, for them troubleshooting will be difficult without understanding.

The term “Black Box” can also be used for “I don’t know something that you don't know”.

This is in reality more the case than we think.

However, I agree that a black box must have some content that is put in before and the box is painted black afterwards.

And, if pneumatic conveying is so researched and understood, remains the question why is there no common understanding and design approach and still there are the many requests here on this forum about non- performing systems.

May be the combination between theory and practice is not yet made?

What now?

Teus ■

While the pneumatic conveying market may be thought of as big, it is clear that this is not the case for commercial pneumatic conveying design software.

Basic market economics dictate the number of products and the cost per unit. If there was a large demand there would be a significantly greater number of products on the market as companies sought to cash in on the opportunity. Look at the CAD market, here there is a large demand for software, catered for by software ranging from freeware to ten's of thousands of US$. So, as there aren't a myriad of pneumatic design applications, the demand cannot be there. ■

Dear designer,

Considering the many companies offering pneumatic conveying installations and equipment, this market must be substantial. After all, they are all making a living out of it.

Pneumatic conveying software can only be used for pneumatic conveying installations as conveyor belt software can only be used for conveyor belts.

Indeed, the software market for dedicated software is limited to the respective industry.

That does not mean that the industry itself is small.

However, CAD software is useful in any industry and therefore CAD software has a greater market.

Nevertheless, Mr. Andrs (who started this thread) is not really served with information that allows him to calculate pneumatic conveying installations.

May be that is also a good thing, because using calculation software without proper and full understanding of the theory and practice can result in unwanted consequences.

Mr. Andrs has to keep up his own trousers or consult a pneumatic conveying expert (with calculation software and field experience) or develop his own software.

There might be a myriad of pneumatic design applications, pneumatic conveying follows the same rules of physics everywhere, which can be handled by a basic algorithm.

Supply and demand.

In this case supply is low and demand???

May be the demand is there (being able to calculate your equipment better than the competition is beneficial) but the willingness to pay the price is low.

Your argument of economics seems to rule everything, I agree to that.

Have a nice day

Teus

How much energy could be saved if all pneumatic conveying installations were designd and working as energy efficient as possible? ■