Like most mechanical components, developments in chains over the years have resulted in improvements, with variants available that last longer, suit extremes of environment or temperature, and are corrosion resistance. Here we take a look at three of the latest chain products available in the UK and the features they offer.
For many years, chains have provided a simple and reliable method of power transmission for a wide range of machinery, ranging from agricultural equipment to conveyor systems. However, the individual application and the environment in which the chain is to be installed means there are a number of considerations – the tensile strength demanded, wear life, lubrication demands, ability to withstand chemicals or seawater without corroding, ability to withstand extremes of temperatures, the amount of noise produced, plus many more.
Chains that exhibit signs of rust need to be replaced or failure can occur. As a solution, FB Chain has introduced a leaf chain that, it claims, will remain rust-free for at least six years. The SuperShield chain is said to be particularly suitable for use with forklift trucks and other materials handling products which operate in harsh outdoor environments, or where regular equipment washdown occurs.
The chain undergoes a three-stage corrosion protection process. It is pre-treated before a protective coating is applied and, once this has cured, a second top coat is added. The absence of acids or electrolysis in the coating process assures freedom from hydrogen embrittlement, which is known for causing cracking problems with zinc plated chain. There is also no reduction in breaking strength.
The company claims that under tests designed to simulate a highly corrosive atmosphere, the SuperShield chain remained rust-free for over 600 hours; while ‘standard’ untreated chain began to rust after 12 hours and zinc-plated chain developed signs of corrosion after 70 hours.
Tsubaki, meanwhile, is offering four versions of its BS/DIN European Standard Chain for use across the widest range of operating environments – including low temperature, sanitary, outdoor, and wet and humid atmospheres.
In the ‘corrosion resistant’ category are BS PC plastic combination and BS stainless steel chains. BS PC chain offers the benefit of a stainless base, with link plates manufactured from SUS304 and spring clips from SUS301. These materials combine with inner chain links of engineering plastic to produce high levels of corrosion resistance, and the additional benefits of lube-free operation, low noise performance and weight saving: BS PC chain is 50% lighter than BS standard roller chain, claims the company.
The BS stainless steel chain is designed for more aggressive environments such as underwater, acidic and alkaline applications, and operation in temperatures from -20°C to +400°C. All basic components of this chain are manufactured from SUS304 stainless steel, except the spring clips, which are made of SUS301. Variants are also available for extremely arduous conditions, including a Titanium chain (ANSI).
Corrosion protected chains complement the two versions above. With these, the BS N.E.P. chain is suitable for use in environments exposed to seawater, acid rain and other adverse weather conditions, and doesn’t contain any chemically hazardous substances such as Hexavalent Chromium, Lead, Cadmium and Mercury. BS N.E.P. chain is a standard Tsubaki BS chain that has undergone a special surface treatment process. The link plates, bushes and bearing pins have a special three-stage coating; and the chain rollers have a coating designed to resist corrosive conditions. Kilowatt ratings for N.E.P. chain are the same as those for corresponding sizes of Tsubaki standard BS chain, but with a higher working temperature range of -10°C to +150°C. A high temperature lubricant is available for operations above 60°C. Also available is BS NP Chain, which offers light corrosion resistance and is suitable for outdoor conditions with exposure to water. This has an operating temperature range of -10 to +60°C.
Improved roller chain
For where a significantly extended service life is required, iwis is offering the Everlast Plus series, an improved generation of low-maintenance roller chains, coated in black to distinguish them from their predecessors.
The improved properties are said to result mainly from the improved modern sintered materials from which they are made. The chains have new oil-soaked sintered bushes and a slightly modified bolt specification, and under laboratory tests showed an improvement in wear lifespan of more than 300%, claims the company.
The Everlast Plus product programme fulfils all requirements of ISO 606, DIN 8187 and DIN 8188. The only change in the chain’s geometrical design is the slightly protruding track bushing, which significantly reduces friction between inner and outer guide plates. A carefully applied pretension improves the chain’s run-in behaviour.
The new chains are available in sizes 06B to 16B and ANSI 40 to 160. An extended range of chains with attachment parts is already being planned and will be available this year.
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