INDUSTRIAL AND ENGINEERING CHEiMISTRY growth of the chemical ware business, it was found disadvantageous to carry on both lines of manufacture under the same management, and the German-American Stoneware Works was incorporated to take over the chemical ware business under the control of the German corporation. In 1919 the German holdings were taken over and ultimately sold by the Alien Property Custodian and the name was changed to the General Ceramics Company. The stock is now 94.5 per cent American-owned; of the remainder 5 per cent is held by the Deutsche Ton- und Steinzeugwerke and 0.5 per cent by the Steatit-Magnesia Corporation in consideration of the privilege of utilizing all improvements made in equipment and in methods of manufacture a t the German plants. The General Ceramics Company have therefore at their disposition the accumulated experience of practically the entire European industry and are in touch with the latest developments in stoneware equipment throughout the world. Full advantage is taken of these facilities by frequent visits of their technical men to the European plants and to the chemical and other factories where the products of these plants are in service. The great fund of technical information thus made available has to be supplemented by constant investigation in the laboratory of the various raw materials used (all of which are of American production), as it is found that batches taken from the same mine may differ widely in physical and chemical properties. The development of special clay bodies to meet certain specific requirements is another important branch of this work. How successful this has been is indicated by a comparison of the physical properties of special bodies made in 1921 with similar ware made in 1927: 1921 1460 65,000 7,900,000 0.0000027
Specific heat Thermal conductivity, K
0.188 0.8
1927 4080 113,000 5,900,000 0.0000019 0.199 2.0
To Fred A. Whitaker, superintendent of the Keasbey, N. J., plant, is due the credit for the high standard of material and workmanship maintained in the chemical ware products of the General Ceramics Company. He has been with the company more than twenty years, having gained his experience a t the German plants.
Vol. 20, No. 5
From 1907 the business of the General Ceramics Company was almost entirely with the chemical industry. The war caused an enormous increase in the demand for their products for use in the manufacture of explosives and poison gas, and to meet this demand their manufacturing facilities had to be very greatly augmented. The armistice consequently found them, like many other manufacturing concerns in this country, with a plant much larger in capacity than their normal business would justify. Efforts were therefore made to find outlets for their product outside the chemical industry, and the success of these efforts is evidenced by the fact that every year since the armistice has seen a substantial increase in their sales, with the exception of 1924 when the total of the previous year was not quite reached. This steady increase in the consumption of acid-proof clay products is the more remarkable when we consider the large array of so-called acid-resistant materials that have been offered to the chemical industry during the past twenty years which might have been expected to affect adversely the consumption of chemical ware. These favorable results are also due in part to a change in the mental attitude of the chemical industry to the use of chemical ware. Before the General Ceramics Company entered this field only simple shapes of comparatively small dimensions were made in this country, and when large or complicated equipment was required, or where exceptional conditions had to be met, the stoneware had to be imported. Consequently the chemical manufacturer looked to other materials of construction and chemical ware was used only where nothing else would stand up. Now that a high-grade product is made here, this prejudice has practically disappeared and the chemical manufacturer has been persuaded that clay products are among the most permanent and least expensive materials in which to manufacture acids and other corrosives. The user of these chemicals has also been made to realize that the logical material in which to handle corrosives is the material in which they are manufactured. The potential field for the use of acid-proof clay products is so broad that there is no reason to doubi that the success that has attended this industry will be even more remarkable in the future. PERCY C. KINGSBURY
A Simple Automatic Control of Vacuum' S. P. Miller and P.V. McKinney THECOLLEGE OF WOOSTER, WOOSIER,OHIO
N T H E course of a recent investigation in the vacuum Inecessary fractionation of petroleum lubricating oils it was found t o have an automatic control of the vacuum pressure. After a search of the literature the Bureau of Mines method2 was selected. I n adapting this method to a college laboratory, rather more restricted in its engineering facilities than the bureau, the valve presented some difficulty. The following is therefore offered as a workable modification which can be constructed in any college or industrial laboratory. The vacuum produced b y a standard pump is to be controlled b y a valve to the atmosphere. The simple device of a fine capillary opening closed by a solid rubber stopper seating against it is used for this valve. The stopper is mounted on the end of the arm of a n electromagnet. The vibrator of an old bell was reconstructed for this purpose. It is operated b y platinum contacts in the mercury of the manometer, which is so adjusted as to close the circuit when 1
Received February 29, 1928.
* Bur. Mines, Repts. Invcsfigalions 2819 (July, 1927).
the desired pressure is attained. The electromagnet is mounted vertically and the arm bent down to a right angle. The lower end of the rubber To M L n o m a t r r stopper is smoothed and softened by washing with s o d i u m hydroxide. The inner tube of a blast lamp makes a n excellent capillary and is supported by wooden cleats. The nozzle is filed to a rather s h a m tir, and has an opening ofabout 0.4 mm. diameter. To ~9actcl.r This device held vacuum reduced to 5 mm. pressure, a t which the p l a t i n u m points of the manometer ~ V d c ~ ~ had ~ d been ~ k set and autobRd Manometer matically controlled within 0.3 mm.
26
