The developing of the wash wheel

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  • The developing of the wash wheel

    Stuart S Smith

    The current wash wheel, used for wash fastness testing, is very closely related to its predecessors. Stuart Smith tells us more.

    Although dyed clothes have always faded because of exposure to light, washing and other causes, testing for and evaluating the degree of such fading is a relatively recent operation. These days, it is a highly technical process, often involving computers to analyse data and shade differences, but machines very similar to some of the original designs from the 1920s and 1930s are still in existence.

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    The wash wheel old . . .

    Most test inshumentation available today was developed after World War 11. The demand for quality control was fuelled by dye and fibre technology improvements and increasing public awareness. A realisation of environmental matters has had a similar effect recently.

    Material testing is the evaluation of physical performance andor chemical properties. Whilst the Society has always been to the fore in its involvement in establishing procedures, particularly in i d e n w n g dyestuff properties, there has also been considerable input by research institutes and major high street stores. Consequently, the manufacturers of test equipment usually respond to specific needs rather than working as the instigators of new procedures or standards. The last ten years and its developments in microchip technology has proved a dramatic stimulus to the instrument engineering industry, and much of todays equipment not only provides the controlled mechanics for a particular test, but is also the impartial analyst and communicator.

    development of a machine for testing is that used for evaluating wash fastness, one of the first such machines to be

    Perhaps the best example of the

    created. The AATCC can be credited with the first innovation in the area, and it introduced the Launderometer in the late 1920s. The aim was to produce a means by which an impersonal and reproduciblc test could be made. The Launderonieter provided a standard and defined means of agitation at a controlled temperature in response to the realisation that the so- called standard controlled test methods of the day, stating temperature, hme and soap solution, when carried out in different laboratories produced different results. This was not surprising when one considers the following quotation from the SDCs 1934 publication, Fasttress fu wrrslririg.

    In the past, the majority of tests were carried out by stirring a plait of the sample with undyed material in the test liquor in a beaker, a method that lends itself to irregular results. It is now recommended that the samples are used as fabrics whenever this is possible, and the dyed yarns or sliver are first knitted and then tested in this form.

    wheel, was introduced in the same year. Similar to the American machine, it had some important improvements. The original British wash wheel was designed by the Calico Printers Association, and was made by Longclose Engineering of Leeds. It consisted of an aluminium wheel, to which were attached 24 stainless steel jars that were easily openable for filling. The wheel rotated in a bath containing water heated to the desired temperature by gas, and thermostatically maintained. A standard pot was introduced, and the rotation speed set at 40 revolutions a minute, the direction reversing after every five revolutions. This was an important start on the road towards standard wash fastness testing, but a number of other important parameters had not been considered and were later incorporated into the design.

    By the early 1970s, two fundamental but totally different requirements were still considered when it came to wash fastness standardisation. The washing tests, which are quickly and easily made without the use of special apparatus, are

    The British version, known as the wash

    quite adequate for routine testing. On the other hand, they are unsatisfactory for a stmdard grading of dyeings.

    During the post-war years, the wash wheel found use, but most dyers and consumerS still appeared to accept the nominal values provided by the dyer or dyestuff manufacturers. The emergence of high street stores in the field of quality control made the industry realise that it had to become fully accountable.

    Those who did not possess wash whcvls continued to use hand-stirred beakers and other such mechanical devices. In many cases, these bore no relationship to thc supposed universal standard test procedure. These inconsistencies led to discussions between Marks & Spencer m d lioaches Engineering in early 1971 to try and find a way to standardise the

    , . . and new

    situation. This led to the modern wash wheel. It was specifically designed to comply with the standards specified by the RSI, IS0 and the SDC, and made its entrdncv at ITMA in Milan in 1975. The wash wheel today is microchip controllrd, and a far cry from the large aluminium wheels with gas burners of the 1930s.

    Stuart Smith is managing director , i t Roaches Engineering, Leek, Staff\, UK, and current SDC president elect

    298 JSDC VOLUME 110 OCTOBER 1994