O c t . , 1913
T H E J O C R N d L OF I,YDCSTRIdL A S D ESGI-VEERISG CHEMISTRY
w a s produced a t the rate of 2,900,000 tons per year a t the Gary, I n d . by-product coke oven plant, on a mixture of 7 6 . 4 per cent Pocahontas and 23.6 per cent high volatile coals. The conservation of coal through producing this amount of coke in b y product ovens instead of bee-hive ovens amounts to about 1,190,ooo tons per year. It has been found by the United States Steel Corporation t h a t the coke produced in by-product ovens, when properly made, is fully equal in quality to t h a t obtained in beehive ovens; and t h a t it is possible to utilize a larger variety of coals, when properly selected and mixed, including coals which up t o the present time have been practically regarded as “noncoking.” and make a highly satisfactory metallurgical coke. T h e by-product plant can be erected near the blast furnaces and it is practicable t o ship to it coking coals from any radius within favorable freight rate; this, however, is not the case with the bee-hive ovens, which, in most cases, are placed near the coal mine which supplies the coal, and, when the mine is exhausted, the bee-hive plant has t o be abandoned. Blauvelt pointed out t h a t the first ovens in this country coked 1 4 tons of coal per oven per 2 4 hours, and t h a t 2 j ovens, with a carbonizing capacity of I I O tons a day, were regarded as the proper unit for one crew of men. “ T h e oven of to-day is carbonizing 20 tons per day, and practically the same crew of men, with the help of modern machi will handle j o ovens He stated that from or more, carbonizing 1,000 tons per d 40,000,000 t o jo,ooo,ooo feet per day of illuminating gas from coke ovens are now produced and sold in the Vnited States. T h e following points were indicated b y Blauvelt as important to a well-designed oven: Largest yield of surplus gas; ability to substitute producer gas for oven fuel gas; maximum yield of by-products; maxirnun yield of good coke ; shortest coking time ; lowest cost of operation and repairs; simple and strong, with weight properly distributed. -4twater called attention to the fact t h a t the recovery oven has achieved a definite place as a part of the steel-making process, and t h a t it presents economies and advantages with which the present-day steel manufacturers must reckon. bleissner had referred to the employment of benzol as a motor fuel; Atwater cited the case of a truck engaged in general city delivery work. On a six months’ test with benzol alone as a fuel, a gallon of benzol yielded 1 5 per cent more work than a gallon of gasolene; based on an equal number of heat units supplied the efficiency was about the same. “NERADOL D”, A SYNTHETIC TANNIN Stiasny, in the course of a paper on artificial tannins,’ gives an account of the production of “ syntans ” (synthetic tannins), one of which products has been placed on the market by the Badische Company, Ltd., under the name of “Seradol D.” Syntans are condensation products which may be produced either by heating phenol; with formaldehyde in a slightly acid solution and solubilizing the resinous products thus obtained by means of sulfuric acid, or they can be made by first sulfonating the phenols and then condensing them with formaldehyde under such conditions that only soluble products are formed. “Neradol D ” resembles, in its appearance, a vegetable tannin extract of bright color. The analogy between this product and natural tannins is shown by the following behavior of “ Seradol D : ” 1ts”water solution is of a semi-colloidal character, passing a semi- permeable membrane only slowly and giving n precipitate with gelatine solution. Iron salts produce a deep hluish violet coloration, and a IO per cent solution of iron alum is a suitable means of controlling the course of “Neradol D ” tannage; this is done by placing a fexv drops of the iron solution 011 the fresh cut of a half-tanned hide, when the tanned layers are colored deep blue. Lead acetate as well as aniline hydrochloride give precipitates with “h-eradol D.” Stiasny makes 1
Ciiani. i I - o r l d . 2 , S o . 7 , 2 1 G .
See also THISJ O U R X A L , 6 , 7 0 5 .
863
special mention of the very bright color of solutions of “Keradol D ” and of the complete solubility in cold water-distinct advantages over the ordinary tannin extracts. It is said that the real character of “Seradol D ” is t h a t of a light leather tannin, and that sumach and gambier are those natural tannins whose effects have the greatest resemblance to t h a t of “rieradol D.” It may be used a s a bleaching agent of dark-colored leather; in this case the retanning action of this artificial tannin prevents loss of weight, which accompanies most of the usual methods of bleaching heavy leathers. ___THE CAUSES AND PREVENTION OF SEWER PIPE FAILURES
It has been stated that, with the inclusion of cement pipe and the cost of labor and materials, it is probable t h a t $75,ooo,ooo are spent annually in this country in the construction of sewers and drains. This expenditure has been largely based upon a visual examination of the pipe or tile, and a conjectural inference as to the loads which it may be expected t o carry safely. IVith a view of developing a correct method of calculating the loads on pipe and of preparing adequate standard specifications for the quality of drain tile and sewer pipe, the Engineering Experiment Station of Iowa State College has conducted a series of experiments, the results of which are reported by Engineering Record. 68, 46; these are presented a t some length on account of their interest to the ceramic and sanitary engineer. The following general conclusions reached as t o the failure of drain tile and sewer pipe in ditches are based on extensive data obtained from drainage engineers: I . There h a r e been a large number of failures of drain tile and sewer pipe by cracking in ditches, and there is a wide prevalence of cracked pipe in existing sewers and drains. The cracking is generally confined to pipe larger than 14 in. in diameter. Engineers have not properly appreciated either the extent or the importance, nor have they fully understood the causes, of cracking of drain tile and sewer pipe in ditches. 2 . The principal cause of the cracking of the drain tile and sewer pipe in ditches is simply that, as a t present manufactured, sizes larger than I j in. in diameter are very generally too weak to carry the weight resting upon them from more than a few feet depth of ditch filling. 3. In very many cases it is entirely impossible to prevent cracking in ditches of drain tile and sewer pipe as a t present manufactured by any possible reasonable amount of care in bedding and laying the pipe and refilling the ditches, -1material difference in the carrying power of the pipe, however, can be made by proper care in bedding and laying. 4. Drain tile and sewer pipe crack more readily in ditches with hard bottoms than when laid on slightly yielding soils j . I t is reasonable, advantageous and necessary to require the pipe-laying contractor carefully t o shape the bottom of the ditch to fit the under half of the pipe surface, and to bed the pipe carefully for this distance in sand or granular soil, so as to secure a firm, uniform bearing. 6 . Drain tile and sewer pipe are so rigid and crack from such slight distortions, as compared with the yielding of the most solidly tamped earth filling, t h a t it is not feasible to prevent cracking by tamping the ditch filling on each side of thc pipe a t the midheight. Such side tamping, however, should always be required, and thoroughly done, for i t is of great value in preventing the collapse of pipe after it is cracked. j. IThere the pipe is found to crack in spite of faithful observance of the specifications stated in j and 6 above, the only effective remedy, other than using stronger pipe, is to bed the pipe in concrete up to the midheight. Such concrete can be lean, and need not be thick if the soil is firm, but must thoroughly fill all spaces between the lower half of the pipe and the bottom and sides of the ditch.
