This concept was developed conceptually by Alan Huth when he worked at the Clinton Coal Loader at Gladstone Qld. in the mid '80's. He contracted Paul Sundstrom of Tasman Engineers to do the engineering detail of his concept. I met up with Alan and Paul in the late '80's as part of research we were doing on transfer chute design and we ie Gulf and Tasman joined forces for about 3-4 years taking the technology beyond washed coal applications. We split to do our own thing when Tasman and Warajay Engineering merged in the early 90's. We continued to work with such entities as the CRA-ATD facility in Bently Perth. Overall we have always credited Alan Huth for developing the concept, initially for a shiploading application and he has been recognised in the early 90's for the pioneering work he did in this and other areas.

There will be some who will say the concept of curved deflectors were used before this but when we talk hood and spoons we refer to a design that encompasses controlling the material flow using accurate projection of the material trajectories such that impact and spillage is absolutely minimised. The first instance of the concept being applied outside of Australia to my knowledge was by Larry Nordell at Palabora in the mid '90's and this chute is documented. Today the concept is applied very widely and is being used to dewater material streams by picking up on the differences in the trajectories of ROM material and water and/or water laden slurries and also in dustless transfer applications where, by carefully controlling the material flow through the transfer, we can almost eliminate the generation of dust at a transfer point without a baghouse. A case in point is an application we did for Comalco at Bell Bay on alumina transfer that was very successful and gave far better results than any baghouse. For those that could be interested in this I can send you details.

There are a number of papers available starting with one that Paul and I presented in I believe 1992 at an engineering conference in Rockhampton

covering "hood and spoon" transfers. Until recent times when the University of Newcastle started publishing some of their research work on material trajectories there has, however, not been a lot of accurate pulications on the trajectory calculations. It is this plus how to design the elements to retain flow control that remains the core to this technology if it is to be applied and used successfully in all apllications. It is also the amount of engineering required that makes this technology more expensive than alternate transfer chute designs.

Col Benjamin

Gulf Conveyor systems P/L

colin.benjamin@gcsm.com.au ■

Dr. Jerry Johanson of Jenike and Johanson worked for US Steel back in the 1960's (according to my memory). He worked for/with Hendrik Colijn.

Henk was a lead scientist at US Steel in charge of bins, bunkers, silos, chutes, ... flow physics.

A full scale curved chute model was fabricated and used as a test bed for various materials and moistures. Products were introduced to the chute system and high speed photography was used to capture the surface effects that are observable with the camera. A report was written on the subject chute and flow dynamics. The surface pitch could be altered to render various product speeds. ■

Hi there Matt..

I first used hoods back in the 80's. They are very good for sticky materials like power staion ash with lots of sticky fines. (We lined the earlier ones with thick glass)

The fun starts though when you have a spoon collecting at the bottom. You cannot really use the spoon on sticky materials as they tend to not self clear.

The spoon also tends to have an impact spot which I have seen wear out in about two weeks.. even on fine coal..

Also, the hood and spoon has to be set up for the set flow of material through it. You can see why they tend to be unsuitable for VSD applications

Lastly, the hood and spoon is poor for the secondaryhandling of scraper dribblings.

For the above reasons, I have only ever used the hood part (for the ash), and hood and spoons where the client insists. Normally I can talk the clients out of it but some still insist on their use. We have fortunately come a long way since hoods and spoons

Cheers

LSL Tekpro ■

Hi Graham,

You note a concern using hood and spoon with VFD? Proper concepts that can take advantage of changing speed and trajectory is not new. Have you tried it?

How is your experience with ROCKY DEM doing? We hear little from LSL on this subject. Have you tried it yet? High wear spots can easily be avoided using ROCKY. Proper valley angles and internal surface wear are quickly identified.

Larry ■

Hi Larry..

Indeed, we have been using Rocky for some time now.

We use it in parallel with my model based on first principals, and are making good progress.

There are some variables we have to put into the Rocky simulation which we are a bit hazy about, but yes..generally going well.

Cheers

LSL Tekpro ■

Hi Graham,

We also had problems a long time ago with cohesive materials building up in the spoon sections. We now know why and it basically because the design logic we used then and frankly up until recently was flawed. In September after we have fully lodged a patent I will create a post that further explains our findings. Importantly Larry, our design methodology is far more accurate than any computational method, it has just taken us quite some time to get the verifiable proof we needed.

Cheers

Colin Benjamin

Gulf Conveyor Systems Pty. Ltd.

www.conveyorsystemstechnology.com ■

Graham,

Let us clear the haze. Tell us what you want to do, ROCKY parameters you are using, and we can assist in getting them right. ■