industrial environments, manufacturing
Anti corrosion castors is the new buzz word in the industry.
Corrosion, defined crudely, is the degradation of material, altering the
chemical composition of a substance. The most dramatic evidence of corrosion
was the Silver Bridge disaster in 1967, in West Virginia in the United States
of America. This suspension bridge collapsed largely due to the corrosion of
the iron supports under the bridge, killing forty six people. Left unchecked
corrosion in an industrial setting can have equally disastrous and dangerous
consequences.
In industrial environments, manufacturing facilities and institutional workplaces, such as hospitals and food producers, the importance of having anti corrosion castors is paramount. At any time gas and liquids can attack the exposed surface of the castors, which are being used to manoeuvre heavy machinery or equipment. For example a common problem is cleaning of equipment castors and bed castors in hospitals. Corrosion in castors and wheels can have dramatic effects and even lead to premature castor failure. This failure of castors due to corrosion can have huge implications. This premature failure can be due to surface changes after and during corrosion, which can lead to loss in the castors strength and result in brittleness.
Some materials can resist corrosion naturally; however other materials require additional treatments to ensure they remain sound. During the manufacturing process of castors, the metal castor frame undergoes a zinc plating treatment. Zinc plated castor frames provide an effective anti corrosion treatment. Although effective in the majority of situations, certain environments do require the castors to have stainless steel frames, which do not rust or corrode over time. Food manufacturing facilities for example are required to have stainless steel castors, as they can withstand the high level of cleaning and chemicals. Outdoor environments also require the castors to be anti corrosive. For example in Marinas castors are used to manoeuvre boats around the yard. These marine castors can be exposed to harsh weather conditions, sea salt and water. Ensuring castors can withstand such conditions is paramount.
Not only are the castors housings anti corrosive, but also the wheels housed in the castors need to have chemical resistance to corrosive gasses and liquids. When choosing castors and wheels it is important that some consideration is given to the environment they will be working and what chemical substances are present in their place of use. Chemicals used in industrial and institutional settings extend from Acetic Acid to Zinc Rhodanide, and incorporating all the chemicals on the periodic tables in between! The general rule is the harder the wheel, the more resistance they will have. For example nylon, polyurethane and polypropylene wheels show more resistance to a range of chemicals than rubber wheels. Of course this wheel resistance does depend upon the contact duration, concentration of the corrosive substances, as well as humidity and temperature in the working environment. Chemical resistance guides also indicate wheel resistance to certain chemicals, and does not give an indication for chemical mixtures.
As an alternative anti corrosive castor, there are a new breed of synthetic castors on the market which have been specifically designed for institutional environments. These castors have housings made of a resistant polyamide and any metal parts are manufactured out of stainless steel.