One of the main requirement of rotary vessels proper
operating is an assurance of adequate forces' distribution in their support
systems.
Unfortunately, this aim is not always possible to achieve. One of
the obstacle is shape errors of roller raceway such as conicity, saddleback
distortion or characteristic edges, which take place even with correct rollers'
position parameters. They make that the assurance of rotary drum's mechanical
stability is impossible, being a boundary of its free axial motion.
In the
past, and at present, the error roller's replacement with the new one with
cylindrical shape is the antidote to this state.
But this is the economic
groundless activity (dis- and assembly expenses, transport and machining
expenses), and besides, it forces the plant to stop.
The need of the new
solution of this important problem appeared.
Going to satisfy this demand, our firm took on the activity leading to study and
create device to large dimensions and weights rotary parts' resurfacing during
their normal operation.
The attempts of rotary parts regeneration during their operation were performed
for many years, but the imperfection of past control and power transmission
systems and the gap in metrology assortment's field, manifesting as the lack of
precision positioning systems and the lack of the big diameter measuring devices
in the operation conditions, destined this method to fail.
But taking advantages of the processing way into consideration, the temptation
to improve was significant. So, in the first quarter of 1995, after one year of
experiments, we managed to outline final machine tool concept.
Simultaneously
we made the project of precision device to large diameter's measurement during
rotation, with 0.1 mm accuracy.
This device, operating on circumference
measurement principle, arised in 1996 and has been tested during many of rotary
drum inspections.
Soon, we could offer, with a big satisfaction, to our clients usage of full
numerical moveable machine tool.
For the first time, the machine was used during complex rollers of lime kiln
no 1 regeneration in KUJAWY S.A. (LAFARGE) in October 1996.
Work on this plant (3 piers) has lasted for 16 days (24 hours per day).
No disruption appeared and new cylindrical rollers' raceways
restored the proper operation's conditions of support system's rotary elements.
Since that moment, roller regeneration has been the constant
position of our company's services proposal.
ADVANTAGES
- No necessity of expensive and laborious dis- and mantling.
Avoiding of these actions lets us in simply way save time and people's effort.
Besides, this makes, that no heavy equipment such as cranes, jacks etc. are needed.
- Elimination of expensive transportation to and from
regeneration place. Parts, to which the method is destined, are generally large
and heavyweight. Regeneration of them requires massive stationary machine tools,
but they are only in few machine-shops.
- Possibility of process continuity assurance. More than
once, especially in seasonal lines, there are priorities, which force to
uninterrupted plant's operating. It is difficult to reconcile these non drum
stoppage's requirements with replacement of its parts.
In the case mentioned
above this method seems to be irreplaceable, making possible combination of
regeneration with full plant operating.
- Basing on real rotary axis during regeneration. Such
machining datum assures the more proper part's work during its normal usage.
Wrong established rotary axis on stationary device is often the cause of work's
disruptions after part mantling on spot.
APPLICATION
- Rotary vessels rollers' regeneration during their normal operation.
- Regeneration of other large dimensions rotary parts.