Feed Rate Variation
It is not possible to advise properly without more details of the feed system. From the outline information given it would appear likely that there is an erratic flow channel from a hopper to a discharge device that suffers from the behaviour of dynamic arches. If you care to send copies of the relevant drawings to lyn@ajax.co.uk, I will try to advise further.
The other problem noted seems to relate to the failure of bearings on a belt conveyor. If the equipment is working on an aggressive atmosphere with large amounts of fugitive, abrasive dust that cannot be reduces I can only suggest discussions with bearing suppliers to see if better seals are available. If I have missed something in this query, perhaps you will give more details of the problem. ■
Re: Improvement Advice On Solid Transport System
Regarding your mentioned failure of bearings in rollers, generally this should not be a problem with present day development in this area.
I presume that the rollers are operating at atmospheric air temperature. If it is not so, the temperature influence is to be accounted for effect on sealing materials, grease viscosity, etc. Also, if the rollers are sometimes hot and sometimes cold during a day due to operational nature, it will result into severe air breathing by the rollers, wherein grease contaminated with abrasive dust will enter into the bearings. This can result into early failure of the bearings.
Also you are saying that the environment is very dusty and you are frequently re-greasing the rollers. Firstly, I will suggest you to opt for grease sealed for life design, and accept the reasonable life as could be achieved considering grease ageing etc. If you wish to have re-greasing, then grease nipple needs to be thoroughly cleaned before re-greasing to prevent entry of dust alongwith the grease. To me it looks, this will be difficult to achieve and better to have grease sealed for life idlers.
Irrespective of the type of sealing whether re-greasable / non re-greasable; please review the sealing arrangement of the roller. This needs to have multi-stage type so that dust particles will have to cross 3 to 4 barriers before reaching the bearing.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyor.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 5882916 ■
Re: Improvement Advice On Solid Transport System
Adding to Mr. Mulani's answer:
1. Air breathing has been countered in a number of ways as previously addressed in this forum. Our preference is to add air hoes in the roller end disk. The hole is oriented down on the wing rolls and drilled near the shell to help eject any condensate due to hot and cold cycling of temperature in moist air.
2. Grease for-life does not mean the same thing to all parties. We distinguish ball bearing without grease fittings as the sufficient interpretation of some. One needs to add: factory shielded and greased for life to hold the grease in the bearing cavity.
Lawrence Nordell
Conveyor Dynamics, Inc. ■
Re: Improvement Advice On Solid Transport System
Adding to Nordell's answer having omitted roller drives (drive pulleys):
The pillow block bearings need to have a "Taconite" type seal addition that traps the ingress of dust in the outer Taconite labyrinth of the pillow block housing. This is a special cavity perfected many years ago in the dusty Hibbing iron ore range of Minnesota. Most of the world's heavy duty mine conveyors, designed for +10 years of service, implement Taconite seals for pulleys, motors, reducers, and low speed mounted holdbacks.
Ask your bearing supplier for more details. The specific design varies between manufactures. There may be a problem with clearances. The Taconite seal pushes the bearing centers further apart.
If you need further assistance please contact us.
email: nordell@conveyor-dynamics.com
website: www.conveyor-dynamics.com
ph: 360-671-2200
fx: 360-671-8450
Lawrence Nordell
Conveyor Dynamics, Inc. ■
Re: Improvement Advice On Solid Transport System
With respect to the large fluctuation on the injection system, one needs to ask if the it existed from start-up of the system or just developed over time. Unless it is a maintenance issue, it looks like you have unreliable transition from the hopper to the transport system.
With respect to the idlers (roller), I see no reason why there is such a high failure. If the grease is leaving the bearings, it is either because the grease type is not appropriate for the application or because the idler is not properly vented.
We manufacture idler rolls with simple labyrinth seal designs installed in agressive environments and never experienced such problem. In my opinion something simple is hurting your equipment.
Contact us if you need assistance.
Antonio Reis
reis@vitrom.com
www.vitrom.com
Vitrom Manufacturing Consultants. ■
Detail On Fluctuate Problem
THANKS FOR ADVICE,
OUR SYSTEM SUPPLY (NITROGEN) IS CONSISTENT(IN MY OPINION) OUR PIPING DESIGN ARE USING 2 PC 90 DEGREES ELBOW AND 2 PC 135 DEGREES ELBOW. WE NEED TO RELOCATE THE HOPPER IF WE ARE PLAN TO REDUCE ELBOW QUANTITY. THE PIPE LENGTH IS ALMOST THE SAME FOR EACH PIPE (DN 40). AT THE END OF THE LAYOUT WE ATTACHED HOSE. ALL THE ELBOW IS BANK TYPE. PLEASE TO ADVICE ABOUT THESE MATTER FOR MORE DETAIL. ■
Fluctuating Feed
I would need to see a sketch of the hopper to secure a better understanding of the situation. Can you send a drawing to lyn@ajax.co.uk ■
Re: Improvement Advice On Solid Transport System
Considering your grease problem, let us know the type of bearing used. Are they Y-type ? There is a lot of chance for the greasing passages are not matching with the plummerblock and bearing outer race. If the bearing is slightly misaligned, the grease passage will be shut off. You need to take care before and after installation. and also during regular maintenance, while greasing.
Without smart observation, you cannot make out the difference if the grease is passing inside the bearing or not. Also note that the grease quantity inside the bearing will be less compared to other conventional plummerblocks. ■
Improvement advice on solid transport system
Hello,
I am the person who incharge on carbon transport and injection system, HBI / Ferro alloy conveying system at my plant. I would like to request your advice about some matter on both area,
Carbon transport/ injestion system,
The fluctuation of flow is too high, some time its going to reach 40 kg/min (lowest), and sometimes the reading is around 130kg/min without any pressure adjustment. Our system is using silo with capasity 30 tonne and transporting pressure around 5 bar (max. setting pressure), its going to enter daily hopper with capasity 5 tonne that the system is developed by Stein industrie- Injection pressure also around 5 bar. Dispenser capasity is around 1 tonne with 6 bar safety limit switches. Acc. to your experience, what was the main reason of that fluctuation? and what was the best sizes for carbon powder?, at the time being we are using 0.1 to 1 mm.
HBI/Ferro alloy conveying system,
Our area is dusty and a lot of type of grease had been try but at these moment no grease is able to mantain the bearing wether for idle roller or drive roller, almost 30% of the bearing already damaged, on the next three month we going to face hard time to change all the bearing, please to advice me the method to solve this problem. ■