car applications. Cycle times for dumping
can be as fast as 35 sec. per car and
tonnage throughput can reach 5000 or
more tph. Unloading rates can increase
dramatically when multiple dumpers are
installed, in tandem, triple or even
quadruple configuration.
Adumping cycle begins when a
loaded railcar moves into position inside
the dumper barrel. The dumper cradle
begins to rotate and the mechanical
clamp arms descend from their support
posts. By the time rotation reaches 15
˚
,
the spill truss supports the side of the car
and the clamps have locked on. The car
is securely gripped and supported
throughout the rest of the rotation cycle.
Once the car has reached 160
˚
of
rotation, dumping action has been
completed. Barrel movement is then
reversed and the car returns to its upright
position. As this is happening, the
clamps release, the platen locks
disengage, the platen hooks align the rails
with the yard tracks and the now-empty
car is ready to exit the dumper. Faster
unloading times are realised when rotary
dumper installations are matched to unit
trains. To achieve the fastest times and
highest productivity with minimal
personnel, dumpers must be matched to
auxiliary equipment, such as train
positioners, car indexers, travelling
hammermills and track systems designed
to handle high numbers of cars.
When circumstances require it, a
dumper can be adapted and
customised beyond its standard features
to match special site or environmental
considerations. This means that for
bulk-handling requirements that are
even more demanding than the accepted
standards for trains and railcars, choose
a manufacturer that carefully
analyses each potential application to
establish peak forces encountered
during each phase of train unloading.
This ensures the proper sizing of drives,
arm configurations and wheel chocks.
Precise engineering methodology can
assure successful operations for many
decades to come.
Turnover dumper
A turnover dumper can be installed
where a site calls for a combination of a
shallow foundation and track-level
receiving hoppers. Such considerations
lead to lower construction costs and
faster erection schedules. The turnover
dumper is used for low to moderate
throughput applications.
The operational sequence of a
turnover dumper is similar to that of a
rotary dumper. A railcar is positioned on
the platen, clamps lock it into place and
the dumper inverts it to a maximum of
170
˚
. The essential difference between
the two lies with the arcing movement
of a turnover dumper in comparison to
the axial rotation of a rotary. Each car
must be uncoupled and dumped
individually in a turnover dumper.
Heyl & Patterson Inc. is currently
engineering a turnover dumper barrel
for Oxbow Carbon LLC. The unit will be
installed at an Oxbow facility in
Buenos Aires, Argentina, and will be
used to unload fuel-grade coal for use in
its production facility. The new steel
structure, which includes an upgraded
clamping system, will replace a
Heyl & Patterson dumper of the same
style that was originally installed at the
site in 1980. The unloading systemwill
continue to use existing electrical and
mechanical drives.
CR dumper
Somewhat between the rotary and the
turnover is the c-shaped rotary – or CR
– dumper. This style is in use around the
world for high-speed dumping of
random and non-rotary coupled cars.
Rotary-coupled unit trains can be
handled with this same dumper because
the centre of rotation is the same as the
coupling centre. The open-sided feature
of this design allows the arm of the car
positioner or indexer to pass through the
Rotary railcar dumper, manufactured by Heyl & Patterson.
Heyl & Patterson turnover dumper similar to the one being installed in Argentina for
Oxbow Carbon.
56
|
World Coal
|
June 2015
