Safety in Hydraulic Cylinder Lifting Systems - Heavy Movable ...

if we analyze the requiremenfs for these type of cylrlindeas related to the piliars on which the ABS concept is
based we find the fotloMng:
I Isrfiueneal surrounding factors;
Bridges are iocated mostly h coastal or industrialized areas. This impties that the cylinders are subjected
to an aggressive or salq en$ro-onment. The exposure to posSb8e air pollulion (Acid rain) or a salt-water
environment demands for high corrosive resistant design solutions.
Funcgona&w of the finear motor min the hydr~ulic drbe system;
Tpiw3ly the bddge leafs are d&en by a set of Wo or four cyiinders. L should be vesed &at the qiinders
have the capam to lift adlor hold the bpjdge in dynamic as wefl as static load skaQons. The position
indicator systems play a key mfe i4~ the safe and adequate control of the bridge ds'ie.
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s Requirements of the cylinders as mechaniwl construction element of the total;
As per DIN 397634 fhe hydraulic steeB structures in civil engineering should be designed for a life%me of 70
years. For the drive system an expected lifegme of 35 years is required. W& dynamic loaded steels
sbudures exceeding a movement rate 0% 10,000 in 35 years the design should be based on an in%n$e
Iifegme. As bridges fa!! Mhin this category the basis for deign of hydwu!ic cylinders in this aappliwgon is an
infringe Hifetime.
EnvironmnftaI Cond%ions vs. Corrosion Protedion:
Piston rods:
The weakest and wlnerabie element in hydraulic cylinders was twelitionaliy the pidon rod. Since the
intrdoction of the Ceramax coating in 1989 %his belongs to the past. Since the market inQoduc%on "Classic"
Ceramax is recog~ized as a trend setting superior piston rod coating for genera! applicaGons in c~rrosbe and
abrasive envjronmenk dh proven track record. Ceramax is an in-house Rexroth Hydraudy~ae development.
Well over 10.000 cyiinde~ are delweaed Mh Ceramax rod coating.
In 1998 the possibil9 was created to develop and apply engineered coagngs for protedon (corrosion)
against extreme external influences based on new spragng techno1ogy as an add%on to the "Classic"
Ceramax.
Fufier developments %is new spwgng bechnsjogy offew, epsglneered coaBngs, total ~~otecGon
against extreme chemical attack such as exposure to 13.5% HCL in combination with 4 5% HF.
This new spragng process is based on the foilo~ng. The "classic" Ceramax is appPied using a plasma
spraying process. This peasma process is spraying the ceramic matefial M very high temperatures
(approx. 30.000 "GI and relaWely low ve8aW (approx. 2810 rnis). Because of th~ high temperawre only
ceramic matefial is suBabfe because twill not born or oxidize.
Wtfh the new technology the gayer is sprayed using a jet (dh oxygen and fuel) with relahe Iow
tempratures (approx. 2.500 "C) but a very high velocq {(approx. 2.000 mls). Wfi this spragng
process it is possible to compose an engineered layer to a speddic task using carbides {for hardwe=) in a
metallic matrix.
fig. 2 New spraying technology
fig. 1 Plasma spraying
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