Tanjung Priok super port - WorldCargo News Online

CARGO HANDLING
Braking cranes on the run
In 2011 the Japanese Association
for Cargo Handling Machinery
Systems, in operation with the
Ministry of Land, Infrastructure
and Transport, Omaezaki Port and
Shizuoka Prefectural Office conducted
an experiment with dynamic
rail clamps. As a result, dynamic
rail clamps are now recommended
for all Japanese ports.
Not everyone in the braking
industry agrees that rail clamps
that act on the top of the crane
rail are a good option for a dynamic
storm brake. Several manufactures
believe they are a holding
brake only, and cranes should
be equipped with wheel brakes to
stop the crane in the long travel
distance. However, many cranes
are fitted with rail clamps with
brake pads (rather than serrated
shoes) to provide dynamic braking
in an E-stop situation.
Blown away
In January 2010 a crane in the Port
of Omaezaki was blown along the
rail by wind. The port and the organisations
listed above began a
study to try and determine,
amongst other things, whether rail
clamps can effectively stop a crane
in motion, and a realistic coefficient
of friction (CoF) to use
when specifying rail clamps
(known as “rail brakes” in Japan).
The biggest problem with rail
clamps is that the crane rail is the
braking surface. It can be wet,
greasy from hydraulic oil and
other contaminants, warped and
uneven. To test some of these factors,
Omaezaki used a crane on
its west wharf fitted with a rail
clamp with a pressing force of 500
kN on top of the rail, generating
a braking force of around 300 kN
with a maximum stroke of 10mm.
Two sets of brake pads were
used: one measured 290 x 125mm
In an effort to prevent crane
runaways, dynamic rail clamps are
now recommended in Japan
and the other was half that size.
The linings were a metal-based
synthetic resin material.
The dynamic CoF of the brake
was calculated in a series of experiments
where the crane was accelerated
to a predetermined
speed and the emergency stop
button was then pressed. Tests were
repeated over several months to
assess the impact of wear of the
brake pads, in dry and wet conditions
and on a greasy rail.
Wide variations
The first results were quite random,
with dynamic CoFs varying
between 0.1 and 0.4. It made little
difference whether the rail was
wet or dry. Grease and oils, however
dramatically cut the dynamic
CoF to around 0.1, and once the
pads were contaminated this could
not be improved by cleaning.
Further investigation revealed
that the biggest factor affecting
performance was the state of the
crane rail and the clearance between
the rail and brake pad.
When the test was repeated on
another section of crane rail where
the clearance did not exceed the
specifications of the clamp, the
results were much more consistent,
with dynamic CoF values in
the range of 0.22 to 0.36 on wet
and dry rails. Doubling the size of
the brake pad had little effect.
The study concluded that dynamic
rail clamps are able to stop
cranes in a reliable, predictable
manner, but there is a need for rail
clamps that have more stroke tolerance
to accommodate uneven
crane rails. Masharahu Sinohara,
executive officer for engineering
and planning at Osaka Port remarked
that although rail clamps
are not mandatory, they are now
recommended and most new STS
cranes in Japan have them.
Long travel target
In other developments, Chinese
brake manufacturer Jiangxi
Huawu Brake Company has made
developing electromagnetic multidisc
brakes and wheel brakes for
gantry long travel applications a
research priority. In recent years
Huawu has focused on brakes for
wind turbines and it achieved sales
of Yuan50M in this market in
2012. It is now targeting other
industrial applications where imported
products still dominate the
domestic Chinese market, working
with universities and the
Jiangxi Provincial Science and
Technology Department to develop
new products.
As far as growing its export
business is concerned, Huawu recently
stated its intention to “continue
to intensify efforts to develop
the international market.” It
will try to leverage ZPMC’s overseas
spare parts network to build
a sales channel into overseas markets,
but is also building an “international
marketing team” to
promote cooperation with foreign
companies.
Römer into Asia
Germany-based manufacturer of
brakes and other components
Römer Fördertechnik GmbH has
signed an exclusive representation
agreement with Singapore-based
Portek. Portek, which previously
worked with Ican, will be Römer’s
sole representative in the following
markets: Singapore, Indonesia,
Malaysia, Vietnam, Philippines,
Thailand, Laos, Myanmar, Brunei,
Cambodia and Hong Kong. The
agreement also covers countries
where Portek is operating terminals
- currently Algeria, Gabon,
Malta, Rwanda and Latvia.
In its brake product line
Römer has developed a new
thruster called the Turbo brake lifting
system (TBLS) that reduces
the brake actuation time from
350-450 millisecs to 150 millisecs.
Römer builds its own thrusters
under the RBL (Römer Brems-
Lüftgeräte) brand. Depending on
the load, said the company, the
apply time of a regular hydraulic
thruster according to DIN 15430
amounts to ca. 300-500 millisecs.
By a special control of the pump
motor, this apply time is reduced
to about 150 millisecs, independent
of the load (even in case of a
power failure) with integrated uninterrupted
power supply.
The control system reduces the
inrush current and the thermal
load on the motor, which Römer
says will improve service life significantly.
The TBLS can be used
with drum, disk and band brakes.
Römer is making a concerted
push into ports and has supplied
crane OEMs including Hans
Kuenz, Konecranes, Terex, KSR
Germany (part of Kranunion) and
Paceco España. It is also targeting
storm brakes, where it claims that
many brakes are actually undersized
because they are specified with an
unrealistically high CoF for the application.
Römer is adamant that
the only appropriate value is
µ=0.25 according to DIN 15019,
but says this is frequently exceeded.
As regards other crane components,
Römer has developed a
new buffer system that enables the
piston rod of the buffer to retract
Italy-based RIMA Srl has kept up
a busy stream of business this year,
following a strong 2012. It has received
multiple orders for storm
brakes for container handling
cranes, in particular for automated
stacking cranes (ASCs)
and bulk handling cranes, placed
by OEMs in Germany, India,
China and the Middle East. In
addition, there were important orders
for other hydraulic components
including micro-motion control
systems for port cranes and offshore
applications.
In the early part of this year
more orders have come in, from
WorldCargo
news
Römer’s Turbo brake lifting system actuates in just 150 millisecs
when two cranes are working very
closely together, and extend again
when the cranes move apart. This
will be particularly useful on retrofit
applications where space is often
constrained. ❏
RIMA storms forward
OEMs including Mitsubishi
Heavy Industries, Mitsui Engineering
& Shipbuilding, Baltkran
and PHB (in Spain).
Highlight include the orders
from Trans Gulf Port cranes (part
of IMCC) in Abu Dhabi for the
rail clamps and hydraulic trim,
list and skew systems for 10 STS
cranes and the rail brakes for 25
ASCs it is building for DP World,
Jebel Ali Terminal 3.
The 40 ASCs being supplied
by Kalmar to DP World
London Gateway (phase 1) are
also being furnished with
RIMA rail brakes. ❏
RIMA rail clamp on STS container crane in the Far East
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May 2013 71