Ecotribology: Environmentally acceptable tribological practices
Introduction
The ways and measures to reduce the impairment of the environment and the consumption of resources, which means to overcome or, at least, to reduce the problems caused by these aspects are, in general, initiated or enhanced by the following driving forces:
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Environmental facts and ecological needs.
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Public awareness.
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Government directives and regulations.
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Globalisation of markets.
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Economic incentives.
Section snippets
Defining problems and solutions
There are two main aspects which have to be considered:
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Savings of resources and energy.
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Reducing the impact on the environment.
These two main aspects are characterised by the following terms:
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Savings of basic resources and materials.
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Optimum design practices.
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Optimum operation practices.
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Reduced energy consumption.
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Protection of the environment.
These aspects will be explained and discussed in the following chapters.
Savings of resources and materials
The following aspects have to be considered when necessary actions shall be focussed on such savings. They are characterised by:
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Depletion of certain raw materials, e.g. crude oil, coal, metals.
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Energy consumption for extraction and production of raw materials.
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Useful lifetime of products.
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Recovery and recycling of used materials.
Optimum design
All aspects of optimum design practices are characterised by:
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Use of renewable and recycled materials.
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Tribologically appropriate design.
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Production: cutting, forming processes.
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Assembling and dismantling.
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Tribologically appropriate selection of materials.
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Easy machinability and deformability.
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Low friction and wear behaviour: base material, surface films.
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To economise renewable and recycled materials belong:
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Direct and indirect savings of raw materials (materials with limited occurrence).
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Energy savings,
Optimum operation practices
The optimum operation practices are characterises by automatic controls, high efficiencies and reduced consumption of lubricants.
Automatic control results in reduced needed man power and in reduced energy consumption (in many cases).
High efficiencies mean, if possible, using machine element types processing higher efficiencies, e.g. spur gears instead of worm gears, roller bearings, instead of mixed film lubricated journal bearings. The results are: Less consumption of energy.
Reduced
Reduced energy consumption
A reduction of energy consumption can be achieved by direct and indirect savings, as defined below:
- Direct savings
- Primary savings
reduction of mechanical friction losses (operating cost)
- Secondary savings
less frequent replacement of worn and failed parts and less necessity to reproduce them (metal working and maintenance cost)
- Tertiary savings
less expenditure for extraction and reproduction of raw materials needed for the production of parts which have to be replaced (cost of energy content of
Protection of the environment
Best methods to protect the environment include:
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Usage of environmentally acceptable materials.
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Less impairment of the environment by lubricants.
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Fewer leakages.
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Extended lubricant change periods.
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Treatment, recycling and disposal.
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Using environmentally acceptable lubricants.
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Both aspects will be explained more in detail.
The usage of environmentally acceptable materials is characterised by the application and usage of:
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Recycled materials.
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Materials, easy to dispose.
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Materials, which do not impair the
Summary
As summary and conclusion the following (Fig. 4) is used indicating the factors of the environmental evaluation from the
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different raw materials and the steps,
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design material,
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material transport,
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production using materials,
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product transport,
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usage and application until disposal.