dear jones, if you will fabricate the inner cone of silo wall in step construction,you know what will happen,there will be layer of material always on those steps and this layer will protect every feed coming from grabs and to stop the dust generated around this hopper you can go for special design like sandwitch type hopper. ■

Dear Mr. Jones,

Possibly you are referring to protect the hopper from the impact of falling material. If it is so, then the best solution is to provide strong grid with appropriate opening at the hopper mouth, somewhat at lower level from the top edge. This grid will bear most of the impact from falling material and would result into protection to the hopper wall and equipment at the hopper outlet. By the way, what is the size of material and bulk density of material?

If you are referring to protection to hopper from the impact by swing of the grab, then what about the damage to the grab that can occur due to the impact? The grab could be more expensive compared to hopper and will it not need protection? Primarily, the automation for the grab bucket operation should avoid the impact with the hopper. If need be, you may think about improving the automatic operation.

Regards,

Ishwar G Mulani.

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

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

i request hon. mr mulani to wet /give expert comments on our proposal also.

anil seth ■

Dear Shree Anil Seth,

I appreciate your suggestion to me to give thought on your reply. Presently, the basic question is not so clear. Hence, I have given reply considering two possibilities. In this situation, when full data is not known, it is difficult to give opinion about the relative merit of differing suggestion, because the same are subjective in nature. So, it would be inappropriate on my part, to say which one is better. However, if you want to have some specific opinion, please communicate to me on my email.

Regards,

Ishwar G Mulani.

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

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

I think what RJones refers to is damage to receiving hoppers caused by the impact bulk grabs on cranes when unloading bulk materials from ships.

Some crane operators are careless when working under pressure to complete the emptying of a vessel and will swing the grab into the structure of the hopper. The point of impact may be on the outside of the hopper, or the inside of the hopper.

I know they shouldn't, but they have in the past and I'm sure will do again in the future, maybe some of them should be in the demolition business ;-) ■

Dear Mr. Designer,

The effect of impact you are referring can be reduced by placing truck tyres at the likely zone of impact. Also, ship / boat fenders are available which will be more than adequate to prevent the damage from impact. But I think, vehicle tyres are likely to suit the requirement.

Regards,

Ishwar G Mulani.

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

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

I feel you are reffering to unloading hoppr to receive material from ship.

In case hopper is mounted on ship unloader and ship unloader grab damage is in question then same can be solved by automation.

In case of ordinary crane with grab is unloading then it is better to mount hopper on dampers to avoid load of material/ swinging grab.

A R SINGH ■

A R SINGH

To illustrate your comments can you give an example of how you have mounted such a hopper on dampers. ■

Dear designer

The basic question is not clear. Based on the application and downstreem equipment hopper lmounting or other solution can be provided.It is not possible to give solution in isolation.

A R SINGH ■