Re: Johason Indicizer Usage In Evaluation Hopper And Chute Prob…
When in doubt - ask the experts Jenike Johanson Inc.
None of these are actual measured design variables. "Index" means that it is most likely an empirical measurement enabling you to compare flour to cornflakes, or gravel. It is most likely limited to powders, or product with high fines content.
The only measure which relates to design is Arching Index (AI) - which shows recommended hopper outlet to eliminate arching, angle of repose (can't eliminate that), segregation potential, tablet and fill weight variation - does all that come out as inches of throat diameter?
Ratholing Index (RI) is looser - indicates ratholing, lumps formation, and flushing potential - ratholing has to do with hopper outlet size and bottom cone shape. If the product will rathole it can also dump, or flush. I'm not sure about the lumps formation.
Flow Rate Index (FRI) - this indicator is amazing - combining limiting feed rates, fluidization, air current segregation potential, dearation time, press rate and capsule fill rates. I understand that you cannot predict flow rates in anything but a mass-flow bin. So you will need to design a mass-flow bin to start with and all these wonderful things will follow.
Bin Density Index (BDI) - indicates gravimetric capacity. Is this the same as bulk density - which is a parameter you need to design the bin?
Feeder Density Index (FDI) - density to Tableting Press - probably an indication of the highest bulk density achievable into the press. Does this relate to kg/m3 - unknown.
Springback Index (SBI) - indicates special hangup problems - probably not predictable by normal engineering formulae.
The rider seems to be that the base index relates to a 10 ft bin with a 12 inch outlet. If you are dealing with a 30 ft bin other things might happen. Or if you a are using a 4 inch exit pipe the response will be different again.
That's why the Vendor says - these electronic things will give you some indication - but don't believe us - prove it for yourself in your application, and find out what all these indicators mean in your plant. ■
Johason Indicizer Usage in Evaluation Hopper and Chute Problem.
Its very clear for me how we use the indicizer to compare differenct materials to each other using AI, RI, HI, CI, FRI, FDI, BDI. However, if i want to use the 3 indicizers to solve a problem in a hopper or a chute, what is the normal procedure.
What i found In some old reports, that all the results are based on a Hypothetical hopper that is 10 ft.in diameter, with 12- inch outlet diameter. How can I apply the Indicizers to evaluate a Real hopper problem if i am using fixed hypothetical dimentions?
i appreciate if there is any answer to my question, i have read many articles in www.indicizers.com but i didnt find an answer to my question
Regards
Joseph Rizk Fahmy ■