Description of the new Westinghouse plant at Emeryville, CA

EASTBAY'S WESTINGHOUSE

PLANT SHOWS MARVELS Of

MODERN MANUFACTURING

By K. VAN RIBBINK.

That there is a "romance of manufacturing" besides the utility aspect, is something the general public is well aware of, in these days of the industrial century.

The Eastbay region, great industrial center of the Pacific Coast, has numerous factories, practically all of which have something of interest to teach the layman as well as the engineer. The various processes followed constitute a remarkable testimonial to the powers of the human mind.

One of the most interesting of these processes is that through which high voltage porcelain insulators are turned out in the great plant of the Westinghouse Electric Company in Emeryville. Here one sees the natural feldspar, flint and clay stored huge caves, to be presently transformed through a succession of machines into shining porcelain bodies for use in electric transmission lines throughout the West.

The Emeryville plant of the Westinghouse Electric Company was built to better serve the western utilities engaged in the rapid electrical developmentof the Mountain and Pacific Coast States. It is the only high voltage insulator factory in this territory and the first Westinghouse manufacturing unit in the West. More than one hundred men and women are employed in this plant, and a second unit is now in course of construction, upon the completion of which the number of employees will be in more than doubled.

The making of these porcelain insulators is particularly of interest, since it modernizes one of the oldest and finest crafts of human history--that of porcelain manufacturing. The Chinese, back into their remotest dynasties were past masters of this art. From them the Dutch learned much, witness the fame of blue Delft ware. The French with "Sevres Ware" and the English with "old Doulton" followed suit, and fabulous prices are paid to these days for old ornamental porcelain.

The porcelain insulators manufactured by the Westinghouse Co. in the Eastbay plants, require a greater strength, durability and purity than the purely "ornamental porcelain of the ancients and moderns. In these great plants the various substances constituting the porcelain are carefully proportioned, "aged," and processed, and then, before the finished product finds its destination for use in high power transmission lines, and the like, it is submitted to a series of tests that seem almost terrific to the layman. For example—currents of 130,000 to 230,000 volts of electricity are passed on and around the insulators. At such times, the testing department presents the general appearance or a "lightning factory" with darts of forked lightning running up and down the finished articles. One type of insulators, furthermore, is subjected to a 50,000 pounds weight test, to see whether it is possible to pull them apart. The slightest flaw, and the article a rejected.

Of particular interest to Californians is the fact that much of the material used in the process of manufacturing, comes from the California deposits.

The following is a general synopsis of the manufacturing process of the Westinghouse hlgh voltage insulator factory.

"Of the three principal raw materials used in the manufacture of high voltage porcelain bodies, feldspar of excellent quality is obtained from California deposits. The flint is obtained from Illinois and the clays are at present imported from England.

"The raw materials are unloaded and distributed direct from cars into six storage bins, each of 200 tons capacity.

"Charging scales of 1600 pounds capacity, carried on overhead monorail tracts, are used to weigh and convey the materials from the storage bins to the ball mills and blungers. The water used in the grinding and mixing of the materials is accurately measured through a flow meter and proportioned with proper allowance for the moisture content of the clays. Although the flint and feldspar are received ground to a fineness which will permit the materials to pass through a 200 mesh lawn, they are again ground wet in a ball mill before they are mixed with the clays. The china clay and ball clay properly proportioned are mixed in the blungers until all lumps are disintegrated and the fine particles suspended in the water. After the nonplastic materials are ground to the proper fineness they are forced from the "ball mill" into the "blunger" by compressed air and there mixed with the clays which have been previously suspended in water.

"The blunged body or "slip" flows by gravity into storage cisterns and from the cisterns through vibrating lawns, the last of which is 150 mesh, and then through a magnetic separator to large storage tanks.

"The refined slip is then pumped to leaf type filter presses on the floor level where by carefully controlled pressure the water is forced out through filter cloth and the slip reduced to a plastic body with approximately twenty-three per cent water content. After the filter cakes have been removed from the press the body is given a preliminary "pugging" and stored in large closed concrete cellars.

"After removal from the storage cellar the body is again mixed in the "pug mills" and, through dies of proper dimensions and shapes, extruded in columns from which blanks of clay are obtained of the weight required for the size and type of insulator to be made.

"All of the pin type and suspension insulators are formed by the most modern presses in use for insulator manufacture. Blanks of the plastic clay are formed and placed in plaster of paris molds, shaped to conform closely to the top surfaces of the insulator unit. A hot revolving tool is then brought down on the clay in the mold, forcing the clay to flow under pressure and accurately shaping the under surface of the insulator. After the excess clay has been cleaned from the face of the mold and any necessary fettling operations are completed the molds containing the pressed insulator parts are placed in a steam heated release dryer until the pressed ware can be removed from the mold and handled without distorting its shape. The drying of the plastic body, accelerated by the absorption of moisture by the plaster of paris molds, results in sufficient shrinkage to permit the easy removal of the ware from the molds.

"After the pressed ware has been removed from the molds and further properly dried the surface which had been in contact with the mold is trimmed off and the tie wire grooves are cut in the pin type insulators.

"The ware, which is now of the shape of the porcelain part required after firing, is conveyed through a tunnel dryer 90 feet long, in which the moisture content is reduced to that required for successful firing in from 36 to 65 hours, depending upon the size and sections of the insulators. This drying is carried on by circulating air under very accurately controlled temperature and humidity conditions, the temperature being gradually increased and the humidity decreased as the drying progresses.

"The dried insulator parts are then covered with the glazing slip, which has been previously prepared to give the desired color glaze, and which fuses into a glass at the firing temperature of the porcelain body, resulting in a surface that cleans readily.

"The insulators are then placed in refractory contains of "saggers" which are stacked in the kiln. The kilns are fired with California oil and gas.

"After the inspection of the insulators drawn from the kiln they are subjected to a vigorous 60 cycle "flashover" test. The voltage of the 300 K. V. A., 250,000 volt testing transformer used for the 60 cycle flashover and puncture tests is controlled from a panel, from which the operator has an unobstructed view of all tests and high voltage equipment. The uniform regulator of voltage up to 150,000 is accomplished through a 9 K. V. A., 220 volt induction regulator with 100 per cent regulation. The test voltages are indicated at the control panel both by a crest voltmeter operated from the condenser bushing of the transformer and from a special voltmeter winding in the transformer.

"In addition to pin type and guy strain insulators this new Westinghouse plant is now producing 15,000 suspension insulators a month. Manufacturing equipment is provided for a larger production, and additional kilns may be added as soon as a greater output is required to meet the demands for porcelain insulators which are playing a vital part in the economic transmission and distribution of electrical energy in the West."