Re: Impaction - Blow Bars & Apron Gaps
Hi daneh,
Silence was the firm reply. Let us reason together.
1 - apron gaps - I assume you are taling about "fines" as a desirable end product. Larger gaps usually mean coarser product, but it depends on the product handled and on the process. The reason you have not had any responses is because most people have no idea of the answer. You should be able to knock up some sort of test rig in the Lab which will guide your optimisation process without interfering with production.
2 - The shape of the impact bar has an obvious effect on the generation of fines. A dull impact tip cannot generate small particles. The answer again is Lab testing to guide optimisation. And - institute an inspection routine during your short-shuts. Take photos of the tips, and record them against production results. You should be able to plot tip shape against fines production over a period of time. Once the efficiency takes a dive you know it will pay to do a change-over. But how much loss of efficiency can justify a 3 day shut is something your management must assess.
3 - bar swell is a result of metal distortion under stress. Without hammer blows a blacksmith cannot forge metal. Without product you cannot simulate the metal distortion or "swell"
When all else fails - use your left and / or right=brain. Often times the answer is obvious if we just look at the correct mechanical principle applicable to the detail under investigation.
All the best - Sgt John.Rz
http://au.groups.yahoo.com/group/bionicresearch ■
Re: Impaction - Blow Bars & Apron Gaps
thanks, i know that im reaching here, i didnt really expect an answer, just nice to try. i wish lab testing were an option, as the machine's performance in the next week will dictate whether it is replaced with a roll crusher. thanks again for you insights.
regards,
Dane H ■
Impaction - Blow bars & apron gaps
Hopefully this is not becoming a nag, but i would still like further input on the orientation of our impactor in regard to high fines production and high thru-put. here are a few pieces of information from mike goulding @ hazemag canada and my thoughts on each.
1-Using a 2:1 ratio wrt apron gaps. we use a 3/4" first gap and a 1/2" second gap. mike suggested that a 1" first gap will allow more effective use of both aprons. this seems reasonable to me, however do bigger gaps not mean less fines?
2-We just turned our blow bars (it had been more than a year since they were last turned probably 2 years), mike said that applications where fines production desired, sharp leading edges are imperative. this also makes a lot of sense, but am wondering how often is often as far as rotation. this process requires approx 2-3 day shutdown to complete.
3-Our literature says to allow 1/4" for bar swell. mike explained that the bars will likely swell approx 3/8" then become seated. is there any merit in seating our bars during the current shut down to allow more accurate apron settings? or would running the machine sans product not produce the stress causing bar swell?
any input on this would be great; and i in no way am questioning mikes credibility i would just like a more practically based opinion on this matter. thanks ■