Details

BHR: Despite announcing your retirement from the Practical Belt Conveying training course, you have plans to remain involved in the conveyor industry. Can you elaborate on what you have in mind?

DB: Yes, for a long time I have felt that as Australia is one of the world’s largest users of high-capacity belt conveyor systems, we should do more local conveyor engineering research. Hence, the idea to form the proposed Australian Conveyor Research Association materialised.

ABHR: So what are the objectives of this Association?

DB: The whole project is still very much in its infancy and things may well change as we progress with its development. In essence, I plan to form a ‘not for profit’ association of individuals who are employed in the belt conveyor industry in design, construction, operations or maintenance, plus academics and corporations such as engineering consultants, mining companies and equipment suppliers.

The objectives of the Association will be:
• To identify areas of belt conveyor engineering where specific research could increase equipment reliability or reduce operating costs.
• To develop ideas for selected belt conveyor research projects.
• To source funds for specific belt conveyor research projects.
• To arrange for belt conveyor research projects to be implemented.
• To publish the results of the research projects.

ABHR: And how will the Association operate?

DB: The Association will have a management committee, elected by the members, and specialist technical committees will also be established as necessary to progress the selected research projects. Hopefully the major players in the industry will provide financial support to run the Association. Further down the track I envisage that a separate limited company will be established, most likely in WA, to carry out the major research projects and this company would be run by a board whose members would be from the key

sponsor companies. This board would also include at least two senior members of the Association’s management committee.

ABHR: Is there any reason why you would choose to establish a new company to carry out the research projects rather than using existing University research facilities?

DB: That’s a good question and one that a number of people have asked. I have had preliminary discussions with a professor at Curtin University in Perth and in his opinion the planned research projects that I discussed with him were too big for a university to handle and that it would take too long to get the desired results. Some of the research projects that I have in mind are going to be very ambitious and will require million dollar-plus budgets! From preliminary discussions with some of the major mining companies I believe that if these companies contribute large sums of money for this research they will want a ‘bullet proof’ company structure that ensures that once the money has been committed the research will continue to completion and that their company representatives on the board will have some control over how the money is spent and that targets are being met.

It is for these reasons that I believe we will need both the incorporated association to get individuals and corporations involved and the security of a limited company for the actual research, where the big money will be spent.

ABHR: Does this mean that existing university research facilities will be bypassed?

DB: Not necessarily; I will in fact be seeking the support of the academic world and I am sure that there will be a role for the universities in these projects.

ABHR: Do you see yourself as the main player in this new venture?

DB: Initially I will be driving the bus but I am not looking for a full-time role. In fact the Association must be structured such that once established it will run without my input or that of any other specific individual. I see my role as the catalyst required to get the project started after which I would like to take a more backseat role.

ABHR: Can you explain why you believe that this research is necessary?

DB: Certainly, but it might be a long answer! A lot of belt conveyor research has been carried out over the years, particularly in Germany at Hannover University and in the USA by Conveyor Dynamics Inc and others but there are still many areas of conveyor engineering that require further study and one standout topic is drive traction.

Current engineering practice for drive traction calculations on belt conveyors is based on the use of Euler’s rope friction equation that was first published in 1762. Euler’s experiments were conducted using a leather belt on a polished metal drum, which is very different to a belt conveyor drive with hundreds or thousands of kW being transmitted into the belt.

Design based on Euler’s equation is therefore at best an approximation. If the drive traction calculation is too conservative, the selected belt could be stronger and therefore more expensive than necessary. If the selected slack side tension value is too low, the belt may slip at the drive causing reliability problems. Today, the use of ceramic lagging has become very common but we have no idea what sort of stresses this type of lagging generates in the belt. It is my belief and that of others in the industry that ceramic drive pulley lagging may contribute to splice failures.

All applications of Euler’s equation to conveyor drive traction calculations are currently based on the assumption that both the tight side and the slack side belt tensions will be uniform across the width of the belt. In the real world of belt conveyors there are features of the conveyor that will cause the tensions across the belt at a drive pulley to vary, with some parts of the belt width experiencing an increase in tension and other areas a decrease in tension.

The most common of these tension-changing features are trough transitions and a bend or snub pulley that is in contact with the carry side of a worn belt and is located close to the drive pulley. The tension variations across the belt are believed to be the cause of otherwise unexplained belt slip problems that have occurred on some conveyors and more importantly splice failures on some conveyors where these features exist.

While several people have studied tension variations in transitions and certain aspects of drive traction, to the best of my knowledge no one has looked at all the variables affecting drive traction or the affect of not having uniform tension across the belt at the drive. A better understanding of the drive mechanics is clearly required if engineers are to be able to design conveyors with a greater degree of accuracy. Improved knowledge in this area should lead to higher reliability and a reduction in belting costs.

I have given the topic of drive traction a lot of thought and I believe that it would be necessary to build three different test machines to carry out this research. Each of the three machines would have a different role to play in the task of fully understanding the drive mechanics.

The principal objective of this research will be to develop a new drive traction formula that includes all the variables that could affect the result including the elastic modulus of the belt, the drive pulley diameter and the belt velocity.

To ensure meaningful results these test machines will have to operate at real world belt tensions and with different belt types including ST, PN and NN construction. These test machines could also be used to answer the unknowns associated with tension variations across the belt and what happens when ceramic lagging is used . In addition to drive traction, there are many other areas of belt conveyor engineering that the Association could take an active role in researching in the future.

ABHR: Who do you see as the major sponsors for this work? DB: The main beneficiaries will obviously be the end users, i.e. the big mining companies such as BHP Billiton and Rio Tinto plus the big port operators and therefore I would expect these companies to be the major sponsors.

I also believe that the large engineering consultants have a moral responsibility to plough back some of their profits into this type of engineering research or at least to provide financial support for the proposed Association.