Ask not "what are the maximum temperatures that a conveyor structure can sustain", but "my chain conveyor will be subject to a temperature of (.. insert your temperature here ..) degrees C, what materials of construction should I use". ■

"Please reply without re-phrasing my question", and you are the one asking for help...............

Now we know you are talking about 300 deg C we have a benchmark for the temperatures you are talking about.

The following link may serve as a starting point for your work.

http://www.ias.ac.in/matersci/bmsfeb...%20strength%22

Google is a wonderful thing :-) ■

Dear Sir,

Resistance of chains to temperature is mainly limited by the fact that some of the components of the chains such as rollers, bushings, pins and sometimes the links themselves are heat treated components.

This is necessary in order to give them adequate hardness to resist to the huge pressures (high forces localized on small contact areas) generated during the engagement with the sprockets.

In applications inside ovens therefore, it is necessary to verify that the thermal cycle (quick heating in the carrying path and slow cooling in the return path) will not reverse the heat treatment, converting the hardened components back into normal steel, with limited capacity to resist to high contact pressures.

Heating the return path too is not to be considered a viable solution, still the chains will undergo to a thermal cycle during outages and start-ups.

We at Magaldi have designed a specialized "pan conveyor" named Superbelt for hot applications that not uses chains and sprockets, therefore does not have the above mentioned limitations.

The main application is to convey red hot bottom ashes in coal fired power plants.

Mounted directly underneath the boiler and continuously subjected to the radiation of the combustion chamber, it moves tons of red hot clinkers 24 hour/day, with scheduled boiler outages of 2 - 3 years., therefore we can consider this application similar to the one in the furnace mentioned by you.

I do not want to exceed in advertising my company on the forum, therefore if you wish to have more information, please visit us at www.magaldi.com or e-mail us at superbelt@magaldi.com

Regards,

Paolo Magaldi ■

Dear Sir,

We also design bucket elevators which for certain applications are unique and perfectly performing.

On the other hand we strongly think that The Superbelt conveyor, thanks to its unique features, is the best answer to all applications where the transportation of material involves heat, heavy load and abrasion.

Please do not hesitate to contact us, we'll be glad to exchange more information if required.

Kindest Regards ■

Dear Sir,

I have omitted an important information that maybe can let you consider differently the Superbelt technology.

This conveyor, as anticipated in my first reply to the forum, for the Power Plant application is positioned directly under the boiler receiving, evacuating and cooling bottom ash with temperatures up to 750°C, plus direct radiation of the boiler directly on the belt.

Please surf our website at www.magaldi.com and view the MAC System section, you'll find interesting solutions and more information about the Superbelt technology.

Regards ■

Joshi,

I answer you on behalf of Paolo because he is out of the office.

Breaking load of mesh and chains depends from their design.

In your application, we are using a type of mesh with a breaking load of 900 kg/cm of width, this means a breaking load 90 tons over a 1.000 mm belt like the one we are proposing to use in your application.

With the data you gave us, the working load of the mesh will be 15 kg/cm only, with a safety factor of 60!

Therefore in this case, you do not need to look for the lateral hollow pin chains.

Regards, Fabio de Feo ■

Dear Shri Joshi,

The earlier respondents have already gone into specific details. The general approach to deal with the issue could be as below.

1) One has to decide the maximum temperature the steel components would acquire, while passing through the furnace or heating chamber.

2) Steel characteristics at such temperature i.e. the yield strength of steel at such temperature.

3) The safety factor that would be available corresponding to this temperature, and adequacy of this safety factors as per the nature of the equipment.

4) If the component are heat treated, then implication of heating up and cooling on the characteristics of the components i.e. the reduction in the specific characteristics at the temperature and whether the heating cooling will permanently destroy such characteristics.

5) Corrosion effect on steel item due to such heating and cooling. This corrosion effect will also be influenced by the composition of air within the heating chamber (often the air in the heating chamber will have a addition of different gases as compared to the atmospheric air).

6) One has to involve the metallurgist and has to also refer to the applicable literature for the steel.

The above mentions the general approach for self decision. However, one can possibly minimise such exercise if he can see the similar installation and use the prevailing experience about the behaviour of various items for the temperature and application under question. This could be known from the user. The competent and experienced manufacturer of relevant items will have such data based on their study and field experience, however such information will be of proprietary nature.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■