432 



THE INDIA RUBBER WORLD 



[May 1, 1914. 



posed of a complexity of gases, including hydrocarbons, 

 carbon monoxide and dioxide, and, most important from our 

 standpoint, slight quantities of acid and creosote vapors. 

 The acid vapors bring about coagulation, but being in such 

 dilute condition they cannot injure the rubber fibre. Creosote 

 is known to be one of the most powerful preservative agents. 

 Its action on the latex is to eliminate the protein njatter 

 which in time would cause the putrefaction of rubber which 

 is known as tackiness. Finally, the heat of the smoke brings 

 about the evaporation and consequent removal during coagula- 

 tion of a large percentage of the water in the latex. This, it 

 is presumed, will allow a more perfect union of the molecular 

 particles of rubber and a consequent greater intermolecular 

 attraction (cohesion) than if all the water remained until 

 after coagulation. This ought naturally to result in a greater 

 tensile strength. 



Our second contention, namely, that the standard of quality 

 of plantation rubber can be raised to that of Brazilian Tapajoz 

 Fine, can be proven by a series of experiments like those con- 

 ducted by the designers of the smoke-coagulating machine de- 

 scribed below. Furthermore, the latices are drawn from trees 

 of the same species, as already mentioned ; therefore they ought 

 to be, and have been proven to be, very similar in chemical 

 composition, and to yield to the same treatment with similar 

 results. The loss of $20,000,000 per year is therefore an un- 

 qualified waste, and can be avoided, as it is simply the result of 

 uneconomic production methods. 



Regarding our third contention, namely, that the Brazilian 

 process of coagulation can be applied to Eastern plantation con- 

 ditions: We have performed many quantitative experiments which 

 have proven beyond any doubt that the Brazilian coagulation 

 operation can be performed by a machine. 



The slowness and laboriousness of the Brazilian hand process 

 is therefore no more a deterring factor to its use on planta- 

 tions. 



The coagulating machine, which M. H. Korn, civil engineer, 

 and H. W. Farwell, lecturer and instructor in the department 

 of physics at Columbia University, have evolved and patented 

 after three years of study and experimentation, performs the 

 coagulation operation exactly as the Brazilian does it, but with 

 a very great saving in labor and time. The several machine 

 models have shown under exact quantitative experiments that 

 we can coagulate and cure up to l}/2 tons of latex per day of 

 10 hours on one machine, the resulting rubber being exactly like 

 the Brazilian grade of smoke cured rubber. 



The efficiency of the machine and its large capacity are simply 

 the result of : 



(1) A larger coagulating area on which the latex may be 

 exposed to the co- 

 agulating and curing 

 action of the smoke. 



(2) A more undiluted 

 and thorough appli- 

 cation of the smoke 

 constituents. 



(3) A more rapid, ex- 

 act and even applica- 

 tion to the coagulat- 

 ing cylinder of the 

 minutely thin layers 

 of latex, none of 

 them being thicker 

 than 0.008 of an inch 

 (0.2 of one milli- 

 meter). 



(4) The timely use of 

 a correct and evenly 

 preserved smoke- 

 temperature. 



Gexer.\l View of Rubber Coacul.^ting Machine. 



General dimensions; 



6' 0" X 4' 0" X 5' 0". 

 Patented in the plantation 

 rubber producing countries. 



GEXERAL STRUCTURE OF THE COACUL.VTING MACHINE 

 AND ITS MODE OF OPER.\TION. 

 In order to obtain a general conception of the structure of 

 the machine reference will be made to the perspective drawing 

 in the following description : 



The machine consists essentially of a smoke chamber, within 

 which a coagulating cylinder revolves at a constant speed, and 

 which is carried by lugs on the truss frame. A smoke inlet 

 and an exhaust port are so disposed over the surface of the 

 smoke chamber that the coagulating smoke, which is kept at a 

 constant temperature throughout, will completely envelope the 

 coagulating cylinder at all limes. The latex is conveyed from 

 the general receiving tank to the latex-restrvoir seen in the 

 drawing on top and a little to one side of the smoke chamber. 

 The reservoir runs on a track, bolted to the rear of the truss 

 frame, so that it may be moved toward or away from the 

 coagulating cylinder as required. The front face of the reser- 

 voir is fitted with a series of orifices, which are opened and 

 closed by means of gates. These gates are actuated by a central 

 cam shaft and a series of cams. The cam shaft is operated by 

 a set of intermittent or "time" gears, which in turn obtains 

 its power from the main shaft of the coagulating cylinder. 

 This time gearing, not seen in the illustration, is a necessary 

 and ingenious adjunct to the machine, inasmuch as it provides 

 for and automatically takes care of the most disturbing factor 

 in smoke coagulation, namely, the variation in the percentage of 

 water contents in the latex. The rapidity of smoke coagulation 

 depends almost entirely on this. The time gearing gives a 

 range of from one-quarter to five times the average length of 

 time required to completely coagulate a layer of rubber of 

 constant and predetermined thickness. The sectional area of 

 the latex orifices may be varied somewhat, but is ordinarily set so 

 that the flow from them is such as to deposit a layer of latex of 

 0.008 of one inch maximum thickness. The smoke generator is 

 a simple grated combustion chamber so arranged that slow 

 combustion of the fuel will take place in order to generate the 

 maximum amount of smoke. The gases of combustion are 

 drawn into the machine by suction, there set in whirling motion 

 to reach every exposed particle on the surface of each new 

 layer of latex, and are then expelled into the atmosphere. The 

 orifices are protected against any possible clogging by precau- 

 tionary devices, which have shown their effectiveness in actual 

 tests on models of the machine. 



The operation of the machine is somewhat as follows : The 

 batch of milk to be coagulated during the day, and stored in a 

 general receiving tank, is first tested for its water contents by 

 means of a small gage. The percentage of water present being 

 known, the intermittent gearing which fixes the time allowed 



each new layer of 

 latex to coagulate and 

 cure is set by the 

 movement of a setting 

 lever to the correct 

 time gear. The latex 

 is then allowed to 

 run into the reservoir, 

 which it will fill to a 

 certain depth, kept 

 constant throughout the 

 operation. The smoke 

 generator, having been 

 started, it is made to 

 pass into and through 

 the machine. Before 

 entering, however, the 

 gases are brought to 

 the correct tempera- 

 ture for proper curing, 

 considering the water 



Designed by Max Henry Kom, C. E., 



82 Beaver St., New York. 



Hermon W. Farwell, A. B., 



Dept. Physics, Columbia University. 



