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Properties and performance of textiles

Acrylic fibre filter bags for power generation plants answers

Pre test answers

Term	Definition
industrial fabric	Textile structures used in engineering applications.
filter bag	Made from a fabric that has a function to trap or filter.
coal dust cake	Fly ash that has collected as waste.
acrylic fibre	A synthetic filament or staple of petroleum base.
ring spinning	Draws, twists and winds in the one operation.
power station	An industry that manufactures electrical power for society.
S-twist yarn	A yarn that has a left-hand twist.
2 x 2 twill weave	A woven fabric characterised by diagonal lines that float over two yarns.
dimensional stability	A finish that aims to stabilise a fabric through a heat process.
emissions	Substances that are expelled to the atmosphere.

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Activity Answers

In designing filter bags for this specific industry end use, a performance fabric has been engineered to perform in intense heat and chemical environments. Because synthetic Homoacrylic polymers are resistant to high temperatures and chemicals this long chain polymer system is an excellent fibre choice for this industrial end-use. In order for the fabric to filter air and trap fly ash, a twill weave construction using an S-twist yarn is required. The hairy woollen spun yarn has the ability to collect dust and the twill fabric sheds the dust cake easily on shaking. The combination of acrylic properties with twill weave using an S-twist woollen spun system achieves a fabric with superior sustained performance level. Textiles are diverse in their nature and application and the acrylic fibre is a clear choice in helping prevent pollution as we continue with a high demand for power generated from coal fired power stations.
In your own words justify the use of a heat set, twill weave fabric made from an S-twist acrylic spun yarn for the industrial end-use of filter bags for power generation plants.
To answer this question, you must have a good understanding of the glossary definition for justify.

Justify means to support an argument or conclusion.

In your answer you need to demonstrate or support with reasons why a heat set, twill weave fabric made from an S-twist acrylic spun yarn was chosen for this industrial fabric to manufacture filter bags. Your answer should demonstrate an understanding of the properties of textiles.

A heat set finish applied to a fabric for filter bags is necessary because the bag fabric will heat to a possible 140°C. This is an extremely high temperature and the bag fabric will need to withstand such a temperature and not shrink or deteriorate earlier than designed. Filter bags that shrink will not be economically viable for the industry. Heat setting the fabric makes the fabric dimensionally stable and therefore productive for longer periods of time.

A twill weave fabric is chosen because a twill weave inherently sheds soil easily or in this case the ash cake that solidifies on the surface of the fabric is easily shaken off.

An S-twist yarn made of Homoacrylic staple fibres is highly suitable because spun yarns have a hairy surface which allow for greater dust collection. The synthetic filament, Homoacrylic, is resistant to high heat temperatures and industrial chemicals.

This combination of fabric finish, fabric structure, yarn and fibre type creates a high performance textile that can perform at the industry settings required.
Using this web site answer the following questions:
1. State the industrial end-uses for fabrics that Albany International manufacture for the global market (page 3)
  Insulation panels for aerospace and aeronautical applications, filtration fabrics, specialty belting, paper making felts, fibrous cement machine felts, paddings and coverings for the dry cleaning industries, pneumatic conveying media, Nomex high temperature belting.
2. State the fibres that Albany International use for their industrial fabrics and choose one of these fibres and research this fibre further.
  Polyester, acrylic, polyethylene, polypropylene, Nomex, Teflon, polyamide, PPS and fibreglass.
  
  For example, the filament PPS or Polyphenyl-sulphide is classified as a synthetic. It is resistant to dry heat and moist heat to 190°C. Its dry heat operational temperature is an amazing 232°C. This filament doesn't burn and is highly resistant to alkalis, acids and organic solvents.
With reference to the fibre properties chart, design a functional criteria list for a conveyor belt in a biscuit factory then choose a combination from the following options to create your industrial fabric.
A fabric conveyor belt in a biscuit factory would need to be heat resistant to high baking temperatures between 150 to 180°C or above. The fabric would need to be dimensionally stable in high temperature environments and it would also be desirable for the fabric conveyer belt to not shed lint (because you wouldn't want fluff to adhere to the biscuit base). Better fabric choices for a biscuit making conveyor belt would be a heat set, singed needled felt made from a synthetic, multifilament yarn, possibly a Homoacrylic. This combination would be chosen because of the resistance of the acrylic polymer to heat. A synthetic needled felt fabric that has been singed to remove the protruding fibre ends or fluff, would produce a conveyer belt that would perform to the industrial environment.

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