I hope this post is not too boringly technical as I provide some context to what follows in future posts about my life in the 1980s.
The Courtelle plant at Grimsby consisted of three separate factories. South Factory, originally commenced in the 1960s was the oldest. North Factory followed in the early ’70s. West Factory was completed not long before my arrival there in 1978.
South Factory contained six production lines in three pairs, each pair associated with a single chemical plant installation. These pairs were designated Units 1, 2 and 3 and the lines A to F. Typically the chemical plant consisted of a sequence of pumps, heat exchangers and vessels in which the chemical acrylamide was mixed with a solution of sodium thiocyanate. If that sounds like a potentially toxic mixture, it was. This solution was a clear semi-liquid with the consistency of treacle. Heat and pressure caused the acrylonitrile to “polymerise” – basically the molecules were realigned, changing the behaviour of the product. Small quantities of other chemicals were added also to give the finished fibre certain desirable properties.
Strange but True: The metal from which the jets are made is an alloy of Platinum and Rhodium. They are, therefore, extremely valuable and spares are kept in a secure store. Worn jets are sold back to the metal merchant to be recycled.
On the production floor, the mixture was forced through a “jet” – actually a curved metal sheet perforated by several hundred thousand tiny holes – into a bath containing a weak solution of sodium thiocyanate. The sodium thiocyanate from the treacle like liquid was immediately attracted to the weaker solution leaving the polymerised acrylamide, which instantly solidified into hundreds of thousands of fine fibres. These fibres were then stretched by passing between rollers to further reduce their thickness. The fibres were then washed to remove any residual sodium thiocyanate, passed through a bath containing a liquid wax which softened the fibre; if required, a dye bath of the desired colour, and thence to a dryer which consisted of a series of 24 perforated drums through which air was drawn by fans. Above and below the drums were a series of finned tubes containing steam to heat the in-drawn air.
From the dryer the fibres passed between hot plates which applied a crimp to them before dropping through a hole in the floor into a box. Each line held five jet and bath combinations, the fibres from each of which came together before the softener and dye baths to be separated again on exit from the dryer. The whole was usually referred to as a “spinning line”.
The solution of sodium thiocyanate from the baths was pumped back to the chemical plant where an evaporator recreated the strong solution required for the next batch. If this is a fair outline of the nature of South Factory, then North West Factory was a more or less exact replica, with units numbered 4, 5 and 6 and lines G to M. North East Factory contained several lines that operated on slightly different principles and was not much used during my time there. West Factory, referred to as Unit Ten, had 6 lines, designated AA to FF, each with 6 jets.
The plant operated 24 hours a day, seven days a week, except for North West Factory which contained the lines that were shut down, in pairs, for the major overhaul I had been engaged to manage. Except, also, for one eight hour shift each week when one line was shut down for general maintenance and cleaning.
Once I became a permanent member of the Engineering team I began to become involved in further projects, each of which was undertaken with the co-operation of the Management team of the relevant factory. In each case this consisted of an Engineer, responsible for maintenance of all the equipment, a Production Manager for the chemical plant and another for the spinning lines in each of the three factories. There were also an Electrical Engineer and an Instrument Engineer.
The three Factory Engineers, the three Project Engineers (of which I was one) and the Electrical Engineer shared weekend and bank holiday duties on a rota for which we were paid an allowance. Thus I “worked” every seventh weekend and one bank holiday each year. The seven annual bank holidays were rotated so that, in theory and for example, we only had to do Christmas Day once every seven years.
I used quotation marks around “work” because it was only necessary to attend for 3-4 hours on Saturday and Sunday, or the designated bank holiday, to investigate any problems that might have developed over night and to sign work authorisations for such tasks as needed to be tackled by the Engineering craftsmen once you had satisfied yourself that the necessary safety precautions were in place and understood by the work team. Thereafter one would be “on-call” for the remainder of the day should any further problem arise – a rare occasion.
There were, in addition, a Works Engineer, with overall responsibility for all Engineering on the three factories, a Services Engineer who was responsible for the safe operation of the steam and power generating plant and all air and water services, and a Site Engineer whose responsibilities also included the rayon production factory which had been in operation at Grimsby since the 1950s and took wood pulp from SAICCOR, where I had worked six years earlier.