Chicago, IL, United States
The New Lexington High Voltage Porcelain Co., New Lexington, O.
An industry that has grown to be quite a power in this country and one that has not been given very much attention in the clayworking field, due, no doubt, to the secrecy in the manufacture of this class of goods, is the porcelain insulator business. Insulators of all kinds are now made of porcelain, from the small insulator or knob to insulators required to stand a test of over 150,000 volts. These are all made of porcelain and the insulators of the latter type are all of larger size and are made with caps to protect them from the weather and to prevent the insulator from taking up the current. At the factory of the above-named company, nothing is made but what is known as high-voltage stuff, none of the smaller varieties, such as knobs, cleats, rosettes, sockets, tubes, etc., are made there as they devote their attention strictly to the larger class of goods.
The process of manufacture is a great deal the same as the manufacture of pottery ware, although not so intricate as a whiteware pottery where the goods are decorated.
The slip-room or mixing-room where the clay is prepared, is almost identically the same as any ordinary pottery. The clay, flint, spar, etc., are thrown from the cars they come in, into the clay bins which are located just outside of the slip-house. The different clays are then carefully weighed up and wheeled to the blunger mill, which in this case is a large revolving cylinder and not the regular pattern blunger mill. A peculiar thing about the high-voltage-porcelain industry is that they invariably use cylinders to mix their body in and not a regular blunger mill. They claim that a porcelain body may be easier and more thoroughly blunged in a cylinder than it can in a blunger mill, and it certainly is plausible. A hopper is placed over the door of this mill and the clays are then thrown; the mill is run for a certain length of time until the charge is thoroughly blended and the tight door of the machine is then removed and a door With a nozzle on is then placed on in its place. The charge from the blunger, which by the way has been saturated with water in the Munger mill, is then allowed to run into the agitator where it is kept agitated or stirred up. It is not allowed to settle until the workmen are ready to pump it into the filter presses, which is done by means of pressure pumps, forcing the liquid clay from the agitator into the filter presses, from which it comes in the constituency of putty. A peculiar thing about the porcelain business is the fact that a steam pump cannot be operated successfully for pumping clay into a filter press, due, no doubt, to the fact that the body contains so much grit that it cuts the plunger and packing to such an extent that it does not pay to use them.
After the clay comes from the filter presses, sometimes it is stored in a damp clay cellar for as long as two, three, or even four weeks, where they have the necessary room, the longer the better, and is then removed and run through the pugmill. In some factories the clay is not aged at all but is run through the pugmill as soon as received from the filter presses. However, it is best to age the clay somewhat, as aged clay works much easier and makes smoother and much evener ware and it also reduces cracking and breakage at the kilns. The clay is run through the pugmill, which chews it up and removes the air from the mass. A little water is also run into the mill at the same time, tempering the clay to any desired constituency. The porcelain clay, being so tough, is very hard to pug and as they use their clay so hard it also makes this work very tedious to get the clay tempered rightly. Sometimes it is necessary to run the clay through two or three times before this is accomplished. This, of course, depends a great deal upon the kind of pugmill