- 28 June 2006 -

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Optimising product quality

One of the most important driving forces for the development of industrial processes in the present day is the need for better product quality. Ken Sutherland looks at factors involving filtration and separation equipment that are concerned with product quality, and how some industries are improving it.

In the case of most products from industrial manufacture that are either fluids or processed (i.e. not machined) solids, the quality of that product is a vital factor in the success of the manufacturing process, and therefore in its profitability. This is true whether the product is for sale on the retail market, for consumption or household use, or on the business-to-business market, to be employed in some subsequent process.

One major parameter in product quality is usually purity - although for some it is performance that counts, rather than composition. However, the search for better purity is an increasingly important goal.

It is not a new search by any means: purity of a product has always been a good selling point, but what was "pure" a decade ago may be unacceptable now. Certainly "crystal-clear" or "sparkling" are usually good descriptive terms for a liquid product, whether it is to be drunk or rubbed onto the dining room table.

Cloudy can be good

It is, of course, true that purity, in the form of perfect clarity, may not be the desired end result of processing. A crystal clear winterised oil may be needed for, say, lubrication purposes, or to stand in a cold larder, but "real" lemonade is expected to exhibit some cloudiness, while honey lovers are divided between the clear, runny honey devotees and those that like a crystallizing, almost solid product.

So purity must be taken in context, and may be a measure of the absence of deleterious impurities from a mixture of several desirable components.

Product quality requirements

There are a myriad of industrial products, each with its own product quality parameters. The output from any filter can be considered a product, including:

•  a clear liquid, free of suspended solids and/or dissolved material;
•  a liquid suspension, free of particles above a certain size;
•  a waste liquid fit for disposal, and therefore free of solid contaminants above a certain limit, and of as much dissolved matter as possible;
•  inlet air, fit to breathe comfortably, and/or free of abrasive dust;
•  exhaust air, suitable for discharge to the environment and therefore free of solid and gaseous contaminants; and
•  solid material as free from mother liquor and as dry as possible, but with little or no crystal damage, and well suited for subsequent mixing or drying.
This list suggests three main goals for a filtration process: making a product that is right for a subsequent industrial use, or fit for human consumption (ingestion or inhalation), or safe to discharge into the environment. These goals all have powerful controlling forces, whose demands increase steadily, driving the filtration industry to develop better products to meet them.

With these filter product classifications in mind, it can be seen that product quality improvement is necessary in order to:

•  give a high quality final product and so to maximise profits;
•  achieve the very precise requirements for the feed to a subsequent process;
•  protect the users of a ventilated space (home, office or factory) from air-borne contaminants;
•  protect the users of water from harmful contaminants, whether for drinking or process use;
•  save money on materials that would otherwise be wasted, and perhaps permit re-use of such material; and
•  satisfy the requirements of corporate responsibility and/or environmental pressures to protect us and our surroundings from harmful waste products.
It is thus clear that the achievement of better product quality is a multi-faceted objective, with not just greater sales, and therefore higher profits, as the goal.

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