Re: The Johanson Indicizer
Not sure where you are located but the following links may halp:
I believe the system is now marketted by Johanson Innovations in the US (see http://www.indicizer.com/?content=1).
Glasgow Caledonian University in the UK also did a lot of work with Jerry Johanson and this device so may also be able to help (see http://cibsh.gcal.ac.uk/index.html) ■
Indicizer Test Interpretation
We are Diamondback Technology, Inc. and are probably the author of your report (under our former affiliation with JR Johanson, Inc.). We can send you information with regard to the interpretation of the Johanson Indices as well as comments on your current application. Please visit our site at www.diamondbacktechnology.com and select "Testing Services". Click on the Johanson Indicizer System link which will take you to the Johanson Innovations, Inc. site (the current supplier of Johanson Indicizers). Click on the "Indicizer Application Guide" in the "Related Links" area on the right side of the page. It may answer your questions. A graphical interpretation of the Indices is shown on the "Technical Papers" page, "Indices at a Glance".
Maybe, more simply, just e-mail/call me and we can discuss.
Regards,
Lee Dudley
President
Diamondback Technology, Inc.
805-544-3775 x15
805-549-8282 FAX
415-793-1255 mobile
ldudley@diamondbacktechnology.com ■
Re: The Johanson Indicizer
Lee,
thank you for your reply and I have checked out the links and read various references. I still have a slight confusion with regard to the relationship between the measured angles of slide and the Hopper Index and Chute Index.
From your site :-
Hopper Index
"Derived from the wall surface friction angle determined at either the hopper outlet or at the top of the hopper, whichever has the greater friction angle."
Chute Index
"Derived from the chute surface adhesion after impact from a bulk solid."
"Derived" implies to me that a measurement is made and then modified in some way to get the Index.
But from "Flow Indices in the prediction of powder behavior." by Dr Jerry Johanson :-
Hopper Index and Chute Index
.. the Hopper Index (HI) and Chute Index (CI), are determined by the angle of slide or friction angle on a flat plate. The angle of slide is determined by placing a predetermined load on a powder sample confined in a circular ring on a flat plate. The plate is then tipped until the ring, solids and load slip continuously down the plate. The angle at which this occurs is the angle of slide. The arc tan of this angle is the surface friction coefficient between the powder and the plate at the applied pressure. This angle of slide is then interpreted as the HI or the conical half-angle required to cause mass flow.
The value of the CI is similarly determined, except the powder confined in the ring on the plate is first uni-axially compressed onto the plate at 100psf. This compaction load is carefully removed to leave the sample undisturbed on the plate. The plate is then slowly tilted until the unloaded sample breaks away and slides. This slide angle is interpreted as the Chute Angle Index to prevent build-up on chutes.
This implies to me that the measured values are used as the Hopper Index and Chute Index.
Could you please clarify which is the correct interpretation.
Regards ■
Re: The Johanson Indicizer
The HI and CI are measured as described in Dr. Johanson's "Flow Indices in the prediction of powder behavior.". The friction angle of slide against a hopper wall sample (phi prime) is measured as a function of applied normal pressure. The HI equals approximately 42- phi prime. This equation results from the fundamental bulk solids flow curves developed by Dr. Jenike and Dr. Johanson at Utah over 40 years ago. The derivation results from an interpolation to the actual wall pressure for the application. The same is true for CI with the adhesion effect added.
Regards,
Lee Dudley ■
Re: The Johanson Indicizer
Lee,
It did seem to me more likely that the angles of slide were the starting point for establishing the index rather than being the index itself. Thank you for the clarification.
Regards ■
Re: The Johanson Indicizer
Good luck.
Try getting hold of Dr Jerry Johanson, he was said to be retired some 4 years ago , but you might always get him to answer a mail. though the mail I have is in san Luis Obispo , probably with Diamondback, from what I know I believe he sold his assets in that enterprise .
I would also like to have hiis e mail. as we are endeavoring in the unknown , and would like to bounce some ideas with him, from time to time.
Marco Flores. ■
Re: The Johanson Indicizer
Marco, send me an email at
ldudley@diamondbacktechnology.com or call
805-544-3775 x15
I will answer or get an answer from Dr. Johanson as I frequently meet with him.
Regards, ■
The Johanson Indicizer
Can someone help me with some information on the Johanson Indicizer tests.
I have a report from some 8 years back on material tests using the this system, but it is little short on detail and the organisation who did the work no longer exists so I can't ask them.
In particular the report refers to tests to arrive at the Hopper Index (HI) and Chute Index (CI) and gives the results measured in degrees. The notes in the report imply that these values are angles of slide of the material on surfaces representing the walls of the hopper and chute, reference being made to fresh mild steel and rusty mild steel giving two sets of results. But the sets of numbers quoted for HI and CI are significantly different so they can't be just simple angles of slide (fresh mild steel HI=19 deg, CI=33 deg).
If anyone can shed some light on the tests and the origin of the Hopper Index and Chute Index I would much appreciate it. ■