Special Care Instructions - HUPFER TTW/M Betriebsanleitung

Chapter 7
Page 24
7.4

Special Care Instructions

The resistance to corrosion of stainless steels is based on a passive layer which is formed on the surface
when oxygen is admitted. The oxygen in the air is sufficient for the formation of the passive layer, so that
faults or damage to the passive layer can be remedied again automatically by mechanical action.
The passive layer develops or reforms more quickly when the steel comes into contact with flowing water
containing oxygen. The passive layer can be chemically damaged or disrupted by agents having a reducing
(oxygen-consuming) action when the steel comes into contact with them in concentrated form or at high
temperatures.
Such aggressive substances are for example:
substances containing salt and sulphur
chlorides (salts)
seasoning concentrates (e.g. mustard, vinegar essence, seasoning cubes, saline solutions)
Further damages can occur due to:
extraneous rust (e.g. from other components, tools or rust film)
iron particles (e.g. grinding dust)
contact with non-ferrous metals (element formation)
lack of oxygen (e.g. no admission of air, low-oxygen water).
General working principles for the handling of appliances made of "refined stainless steel":
Always keep the surface of appliances made from stainless steel clean and accessible to the air.
Use cleaning agents suitable for stainless steel. No bleaching and chloride-containing cleaning
agents should be used.
Remove layers of lime scale, grease, starch and egg-white daily by cleaning. Corrosion can occur
underneath these layers due to lack of air admission.
After each cleaning operation remove all cleaning agent residues by wiping thoroughly. Afterwards,
the surface should be thoroughly dried.
Do not bring parts made from stainless steel into contact with concentrated acids, seasonings, salts
etc. for longer than is absolutely necessary. Acid fumes which generate during cleaning of tiles also
promote the corrosion of "refined stainless steel".
Avoid damaging the surface of the stainless steel, particularly by metals other than stainless steel.
Residues of extraneous metals produce extremely small amounts of chemical elements which can
cause corrosion. In any case, contact with iron and steel should be avoided because that leads to
extraneous rust. If stainless steel comes into contact with iron (steel wool, steel particles from pipes,
water containing iron), this can be a trigger for corrosion. Therefore, for mechanical cleaning use
exclusively refined steel wool or brushes with natural, plastics or refined steel bristles. Steel wool or
brushes with unalloyed steel lead to extraneous rust due to abrasion.
Tray transport trolley
TTW/M
Cleaning and Care
Special Care Instructions
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