One of the basic principles of product safety in food production is that only ingredients that are safe for humans are used. Neither visible foreign bodies nor trace substances that are difficult to detect and hazardous to health must be allowed to enter the end product. Of course, this requirement also applies to the food production process.

Potential trace materials include, for example, oils or greases used to lubricate the components in the production machines. However, as it is sometimes unavoidable that some lubricant gets into the finished food products, lubricants that are safe for human consumption must be used. Manufacturers of lubricants produce specially designed products whose use is regulated by laws and industry standards. These regulations vary from country to country. However, there are basically three categories of lubricants that may be used in the food industry:

• H1 lubricants: they may accidentally come into contact with the food produced and must not be harmful.
• H2 lubricants: They must not come into contact with foodstuffs and are only to be used in closed systems.
• H3-soluble oils: They may be used to clean or operate equipment or machines that come into contact with food, but must be washed off before use.

As special lubricants for the operation of Tsubaki's drive chains in food technology are expensive, the company looked for alternatives and developed one with the 'Lambda' chain: These drive or conveyor chains are equipped with a self-lubricating function that is designed for permanent lubrication - no re-lubrication is required throughout their service life.

Permanently lubricated

The core concept of the 'Lambda' design is the use of an oil-impregnated sintered bush. It ensures that the chain lubricates itself over its entire service life. The majority of the lubricant remains in the chain so that there is no contamination of products, packaging and other objects.

Exploded view of the 'Lambda' chain from Tsubaki. The sixth generation of the chain is lubricated with NSF-H1 lubricant impregnated into the bushes as standard.

© Tsubaki

The design in detail: The 'Lambda' chain is a roller chain in which a special bushing made of porous sintered material is used. The oil is introduced into the capillaries by means of a vacuum process, thus creating a reservoir for lubricant in the chain. Heating and capillary action during operation allow this lubricant to reach the surface of the sintered bush, where it forms a light lubricating film. This means that the chain does not require any subsequent or additional lubrication; it supplies itself with the necessary lubricant. The roller chains are compatible with standard BS/DIN and ANSI chain sizes.

As the chain's joints are always lubricated, frictional forces are minimized and wear is reduced. This reduces chain maintenance costs. Particularly in industries and applications where expensive lubricants have traditionally been used, additional chain lubricants can be dispensed with, even in difficult environments.

As standard, the 'Lambda' chain is lubricated with the food grade lubricant 'NSF-H1', but H3 oil impregnations are also available on request. The chain is designed to withstand moderate rinsing procedures during the cleaning process at temperatures of up to +150 °C. Versions for use at higher temperatures are available as an option.

Simply installed

To simplify installation, the pin and link plate of a slip-fit locking link are designed as a kind of sliding fit. This locking link usually has a 20% lower fatigue strength than the chain itself. To compensate for this loss and still meet user requirements for easy installation, Tsubaki has developed the stamped ring compaction process. This creates a cold deformation around the pin hole of the link plate. This leads to a residual stress around the pin and thus to an increase in strength. This increases the power transmission back to 100 %. Breakage points on the connecting links are therefore a thing of the past, as a significantly higher fatigue strength is generated around the pin eye of the locking plate.

The chain is fully interchangeable with standard BS roller chains and can therefore be used in existing machines without conversion. The same applies to the use of standard BS sprockets.

Lubricated for life

Tsubaki's first lifetime-lubricated chain was launched 30 years ago. Over the years, the chain has undergone continuous further development: 1988 saw the introduction of the chain in the ANSI standard, and in 1992 the BS/DIN standard was realized. In 1995, the first maintenance-free chains with attachments came onto the market. In 1998, the second generation of the 'X-Lambda' was given optimized joint protection, and in 2005 the BS/DIN series was launched on the market as fully compatible with the usual standard roller chains. In 2012, the developers optimized the oil-impregnated sintered bushes so that they contain more lubricant and therefore have a longer service life. Finally, in 2018, the lubricant contained in the sintered bushes was changed to a food-grade NSF-H1 lubricant.

Author:
Angela Struck Is a freelance journalist and Managing Director of 'Presse Service Büro' in Langenpreising.