This post is little offbeat, its about a booklet on felt used in paper making machines, published in 1975 by a company named Porritts & Spencer. P&S is a UK based company established in 1914, its operative till day as per an online source. The booklet was a complimentary copy my father had received during his tenure at Mysore Paper Mills. I found it in a heap of paper early 2000s, kept it as a souvenir- a 45 year old autographed & dated souvenir. Now I felt like sharing the lovable pictures and informative narration. The booklet is titled: FELT - TO FILL A LONG AND ENDLESS WANT. The following text is transcript of the story as it is. Hoping you enjoy the peek into the history of paper making technology.
For thousands of years man's urge to express himself, progressing from gesture and speech to a need to record for future generations his history and his thoughts, led to the use of whatever materials came easily to hand pictures on stone and clay tablets, to writing on animal skins and papyrus, from which paper as we know it, derives its name. It was around A.D. 105 that a Chinese court official, Ts'ai Lun, invented paper, producing for his emperor Ho Ti's inspection the first ever sheet of paper. Made from stock prepared by mascerating in water the bark of the mulberry tree, hemp waste, old rags and fishnet, the art of paper making was kept a close secret for 500 years.
It eventually found its way to Japan and some 700 years later to the west.
Paper was produced in Italy during the year 1276 by dipping a frame, with a screened bottom, into a vat of stock, lifting it out and allowing it to drain, thus leaving a sheet of mash on the screen. After pressing and drying, a sheet of paper was formed, the size being regulated by the frame size which could be lifted manually from the vat.
It was not until 1798 that the process of papermaking was mechanised. A machine constructed by the Frenchman Nicholas-Louis Robert, consisted of a moving screen belt receiving a continuous flow of stock which delivered an unbroken length of wet paper to a pair of squeeze rollers. This then was the crude forerunner of the modern papermaking machine and this is where we-Porritts & Spencer came into the picture.
The earliest records available show that the Porritt family were textile manufacturers in the year 1808, and during the next hundred years three separate Porritt descendants operated in competition with each other. However, they were re-united in 1914 and in conjunction with J. H. Spencer & Sons, Ltd., Porritts & Spencer Ltd., was created.
To meet the demand of the paper industry more mills were built or acquired until, in 1968, a merger took place between the two major British manufacturers, creating one of the three largest manufacturers of mechanical clothing in the world.
When ancient man felt outraged at another's use of his invention of felt Scapa Group Ltd., now owns or controls more than 20 manufacturing units throughout the world.
Scapa Group Ltd., now owns or controls more than 20 manufacturing units around the world.
The paper manufacturing industry in India has also been growing rapidly and to meet the increasing demand for both woollen-based and cotton felts, Porritts & Spencer (Asia) Ltd. was established with a modern factory at Faridabad, Haryana, which went into production on 26 October 1970. Since then orders continue to pour in, and most types of wet and dryer felts have been produced for almost every paper and board mill in India, leading to very considerable savings in foreign exchange outlays to the nation.
Calling for a much heavier material than is produced in conventional textile mills, machines for papermaker's felt manufacture are designed to be capable of producing material weighing from 400 grams to 4,000 grams per square metre.
The specially equipped quality control laboratory ensures that the woollen yarn conforms to specific requirements of tensile strength required by the customer.
The looms manufacture the basic fabric prior to processing, which at this preliminary stage is referred to as being in the 'grey or greasy state.
Catering to the particular requirements of a partieular machine, felts are literally tailor-made to order. Designs are determined by such factors as the type of papermaking machine, type of paper manufactured, nature of raw materials used, speed of machine and state of stock, such as pH, freeness etc.
After the basic material has been woven to a specific design it is then rendered endless by
manual splicing or felting, requiring a high degree of expertise on the part of each operator. In order to sustain the level of quality called for in what amounts to a totally invisible darn, it could take a single operator a full day to complete just seven inches of splicing. Once felting is completed the material goes to another section where it is slowly turned on rotating rollers to facilitate close examination for faults, which at this 'grey' stage can be conveniently corrected.
The felt is now ready for shrinking or milling to a pre-determined size thus preventing either stretching or narrowing when running at high speed on a paper machine.
After milling the felt is washed and chemically treated for protection against bacterial infestation, moth damage etc.
The endless fabric is now mounted on heavy rolls, one of which is some six feet in diameter and steam heated. After stretching to a pre determined tension the felt rotates and is slowly dried. This controlled process ensures uniform tension at all points when the felt is in use on a paper machine.
To prevent the paper in its wet state being marked by the weave, felts often have fibres teased out of their structure to form a fluffy cover. This is done by rotating the felt and allowing it to contact hundreds of vegetable teazles which are mounted on a revolving drum.
Some felts are made by laying a very uniform layer of wool upon an open woven endless fabric and passing it continuously through a machine equipped with an oscillating board containing many thousands of barbed needles -the needles force the fibres of wool through the fabric and anchor them, thus producing a porous and non-marking felt.
The manufacture of paper also calls for the use of cotton felts. Made from cotton yarn which is wound from a specially constructed creel onto a warping drum under calculated tension to ensure uniform quality in the felt to be produced again, tailor-made to the explicit specifications supplied by the customer great care is exercised to ensure that the felt will run true to the papermaking machine.
Cotton yarn for the weft is run onto specially constructed shuttles which, on the weaving looms, attain speeds of 40 60 m.p.h.
These cotton-felt looms are considerably heavier and wider than looms in a conventional cotton weaving mill. producing wider and much thicker fabric which is subjected to high levels of quality control.
At this weaving stage, an alert worker checks the woven cloth for possible flaws and faults, which can be corrected on the machine.
After a pre-determined length is woven, it is removed and stretched and either hand spliced to make it endless, like a woollen felt, or is fitted with a mechanical seam-a very specialised operation.
Elaborate arrangements are made for maintaining a constant level of temperature and humidity necessary for the various stages of felt production. The units, contained in their own rooms, are in fact giant-sized desert coolers equipped with an immense blower some 7 to 8 feet in diameter, fitted with a proportionately giant-sized duct for distributing conditioned air to all parts of the factory where it is needed.
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