On Thursday I was very grateful to have been given the 'Chance' to visit Pilkingtons at St. Helens on 23rd August, where I was escorted around the rolled plate plant by Brian Quirk, the Chief Engineer and Production Manager. I would like to record my thanks to Brian for an excellent and illuminating tour!
I was accompanied by Ray Drury, the former Chief Engineer at Chance Brothers until 1976, and it is entirely due to Ray that we were afforded this opportunity.
M6 was only "slightly horrendous" (he,he) and there was an accident both ways, plus accompanying rubber-neckers (grrr!) and I'm sooooo glad I don't have to do that trip much.
My flabber was completely gasted by the sheer scale of the rolled plate plant, so it was nice to be able to finally get things into proportion. A composite mixture of sand and cullet is fed into the regenerative tank furnace and the rate it is fed depends entirely on the amount of molten glass (several tons) swilling around. The furnaces are staggering due to the size - and the heat was rather wilting, to say the least! Brian and Ray decided to have a casual chat down the side of one furnace while I melted... :spls: Of course, the weather that day was the hottest this year after a long period of very cool, dull, and rainy weather! :spls: :spls:
The molten glass is then fed between the two rollers (up to 18-in/45cm. dia and about 6-ft/2m in length), with the bottom roller containing the embossed pattern. The ribbon of textured rolled plate glass is still very malleable when it emerges and is still glowing orange. Rollers are replaced on a fairly regular basis and regenerated at the on-site machine shop.
The continuous ribbon of glass then passes through a 100-yard (75-metre)? annealing lehr - the length of which is quite surprising, until you consider the speed of about 300 inches (7.6m) of rolled glass being produced per minute, and this does start to bring things into perspective.
Following this, single sheets of glass are snapped off and then trimmed to a regular width. From the moment the furnace is fed with sand and cullet, all this is an entirely automatic process that just requires a single person to stack and pack the finished glass at the end of the line! OK, there are three other blokes who monitor temperature and alarms from a control room, but otherwise there is no manual intervention unless the sticky stuff hits the whirly bits.
At the machine shop used rollers are sand-blasted to refurbish them. However, some textured rollers, such as the Flemish texture (see photo below), are chrome plated (without any nickel content, as a glass technologist will tell you) to provide a superior finish. When you see a Flemish texture, you begin to understand why this ultra-smooth finish is a requirement. There is quite an interesting story behind Flemish: it was first developed in... [but you can read about this in the book...
Hard to believe that some of the equipment designed and installed by Ray Drury, c.1970, is still
in operation (albeit modified along the way), and that Chance were achieving slightly faster rolling speeds in 1976 than Pilks are today! Brian did point out, however, that the plant output is limited by the furnace volume.
Progress? In some respects yes, but the technology has remained pretty static for the past 30+ years. I suppose the old adage, "if it ain't broke, don't fix it" stands up pretty well.
Any questions, please just ask.