I visited a couple asphalt plants this week. Different manufacturers and different sizes. One thing was common, trunnions were not adjusted properly. In addition, plant crews were hesitant to work on them. Could you please educate the group as to simple methods of adjustment. This seems to be a common problem.
No question being book smart is one thing but someone with experience can in no question create the optimum end result. Before any adjustment is made measurements and many checks must be made. Check things like bearings on trunions, alignment (measure) tire and trunnion wear pattern, chattering of tires, things that may bind the drum etc. The most common mistake made when adjusting trunnions is over adjustment. I adjust 1 face or 1/5 of a turn and wait at least 1 day of running to see results. If the tires are badly worn this could take longer. Patience to see results is a must. Generally the calls I recieve to adjust trunnions is because misalignment has caused big problems. Continually pay attention to the alignment and adjust as required and the tires and trunnions will last a lot longer
Always measure your trunnnions first.. Some may be pushing “down hill” and some “up hill”.. When this happens it can be bad for your trunnions.. We would normally make small adjustents at a time, maybe like 1/6th of a turn or one flat on the adjustment nut.. If its a square head take it one flat.. you can run it for a day or two and watch it and eventually get all your trunions back to “zero” and square everything up.. If the tire is out of balance and does not have a flat face anymore then it makes it harder to adjust..
One reason most people hate working on them is because its very time consuming and then you have to run the pant awhile to see if the adjustment worked, if not then you have to do it all over again. I worked for a company that had a foreman that would make an uphill adjustment one day and then a down hill for two days and then back up hill the next. 5 days a week or how ever many days they ran he would go from zero to up hill back to zero to down hill back to zero and so on.. It would take about an hour and a half every day but his trunnions and his tires on the drum were always if great shape. This was on a 1980 something Barber Green 5 ton batch plant that still runs to this day..
hope this helps some
when i comes to drum/trunnion adjustment, I ask 2 questions.
1 does it need adjusting, 2 is it adjustable.
if your drum is pushing hard either up hill or down hill at a production rate you normally do not run, perhaps not, unless its a susatianable rate that you will run often.
is it adjustable , are the trunnions flat/true, or worn wedge shaped? are the bearings in good shape? if the answer to either is no, then adjusting will be very diffuclt if not impossible. tire wear is another factor. but the fast answer is , since we all have smart phones, i have downloaded a PDF file that makes it as easy as it gets, simply follow the arrow for your drum roatation, ( flipping the phone wich ever way you need to, then set it down right in front of the trunnion and it makes deciding wich way to “cut” it easy, and yes SMALL adjustments are more fruitfull than large ones.
to find the file i use www.industrialkiln.com/images/Roller%20Adjustments.pdf
there is also a mathmatical formula that works
You should look at the Maxam Equipment self aligning trunnion design on their web-site.
I am not an asphalt man but know bearings. To me the trunnion should be thought of as a bearing. And so my add to this is if the trunnion and tire surfaces are already worn, and more than likely unevenly, the problem is compounded exponentially i.e. wear begats more and faster wear. So people who wait until there is a wear problem, are a bigger problem in themselves.