US1718949A - Process of preparing carbon dopes - Google Patents

Description

July 2, 1929. w DIXON 1,718,949

PROCESS OF PREPARING CARBON DOPES Filed March 23, 1927 //VV/V TOR." Hnnow 141/7. 0km,

Patented July 2, 1929.

UNlTE ears @FFEQ HAROLD W. A. DIXON, NEW YORK, N. Y.

PROCESS OF PREPARING CARBON DOPES.

My invention is particularly adapted for the commercial production of the colloid compositions which are used for coating carbon paper and similar fabrics. Such compositions primarily include particles of solid matter such as carbon and dye substances, in suspension in a waxy substance, which is liquid when hot and during the spreading of the coating upon the desired web or textile fabric, and thereafter becomes solid when chilled. Ordinarily, the carbon. coloring matter, and wax-like ingredients of the prospective coating are primarily mixed, in a more or less lumpy state, in kettles which are heated, by steam or otherwise, and provided with means to agitate their contents. The crude magma thus formed is more or less granular and irregular in composition. Therefore, it must be further treated to reduce the size of the particles and render the mass more homogeneous. An essential step in such treatment is the repeated passage of the mass between the members of a milling couple, until the particles in the colloid are reduced to dimen sions of the order of, say, one micron. During such treatment, it is necessary, or at least highly desirable, to maintain the mass heated above atmospheric temperatures, to effect such treatment economically.

Therefore, I have devised an apparatus including a suitable milling couple in conjunction with means for repeatedly passing the colloid through said mill, and that apparatus is the subject matter of my application Serial No. 177,723 filed March 23, 1927, for Letters Patent of the United States. I find it convenient to utilize such apparatus in the method 'herein claimed; the essential feature of the latter being that the conduits and passageways throughout the apparatus are preheated and any waxy deposits therein .dissolved and removed by and with hot oil which is thereafter used as one of the ingredients of the next batch of colloid which is passed through the apparatus to effect comminution of its particles.

In the drawings; Fig. I is a diagrammatic plan view of apparatus including a milling couple and means for repeatedly progressingthe liquid between the opposed surfaces thereof.

Fig. II is a fragmentary and somewhat diagrammatic sectional View of a milling couple of a form which I prefer to employ to present 55 metallic surfaces in opposed spaced relation,

in contact with the opposite faces of a film of the colloid progressed between them.

Fig. III is a fragmentary and somewhat diagrammatic sectional View of a modified form of milling couple which may be substituted for that of Fig. II, in the. apparatus shown in Fig. I.

Fig. IV is a plan View of the valx e structure indicated in Fig. I, but with the rotary valve body turned to the alternative position.

Referring to Fig. I; the two colloid containers 1 and 2, which are preferably steam heated kettles or tanks, are arranged to be alternately connected, by the valve structure 3, with the mill 4 so that, with said valve in the position shown, the colloid is withdrawn from the container 1, passed between the milling couple 5 and 6 in said mill, and discharged into the container 2, by the operation of the pressure pump 8 and suction pump 9 and, with the valve structure 3 in an alternative position shown in Fig. IV, the colloid is withdrawn from said container 2, passed between the members 5 and 6 of said milling couple, in the same direction as before, but returned to said container 1. Said valve may be turned by the handle 7 to the extent limited by the stop lugs 10.

To effect such operation; said container 1 is provided with-the conduit 11, controlled by the cook 12 and leading to the port 13 in the end closure 14 of the valve casing 15. Said port 13 is in registry with one end of the duct 17 which extends through the rotary valve body 18 and then in registry with the port 20 in said closure 14: which is provided with the conduit 21 leading, through said pressure pump 8, to the inlet port 22 in the casing of said mill 4. Said port 22 opens into the mill pressure chamber 23, and the colloid passes thence through the interstice 25 between said milling members 5'and 6, which are continuously maintained in'axially spaced relation. The conoidal configuration of the opposed metallic milling surfaces of said members 5 and 6 is such that when they are rotated at sufficient velocity, there is a centrifugal effeet which progresses the colloid in an evolute ath into the vacuum chamber 26 from which it is exhausted, through the conduit 28, by said pump 9, so as to produce a partial vacuum in said vacuum chamber 26. Said conduit 28 leads through said exhaust pump 9 to the port 29 in said end closure 14 of the valve casing 15. Said port 29 is in registry with the end of the duct 30 which extends through said rotary valve body 18 and then in" registry with the port 31 in said closure 14 which is provided with the conduit 33 controlled by the cock 34 and leadinginto said container2.

In the form of mill shown in Fig. III, the conduit 21 discharges into the pressure chamber 36 within the rotor 37, of the milling couple, which has radial ducts 38 leading to its cylindrical perimeter, which is opposed to the internal cylindrical surface of the stator 39. There is a cylindrical interstice 40 between the opposed milling surfaces of said milling couple 37 and 39 through which the milled colloid passes into the vacuum chamber 42 comprising the s aces on both of the axially opposite sides 0 said rotor 37, from which the milled colloid is exhausted into the conduit 28. In that form of mill; rotation of the milling member 37 has such centrifugal e-fi'ect upon the colloid passing through it from the pastes used for coatin chamber 36 as to continually present such colloid under pressure at the interstice 40; but there is no direct centrifugal effect upon the film in said interstice tendin to discharge it from between the members 0% the couple.

However, it is to be understood that any suitable mill structure may be included in the apparatus above described with reference to Fig. I.

In accordance with my method; batches of colloid such as the carbon dope or other color pa er or textile fabrice, as above contemp ate are successively mixed and treated in the ap aratus described and discharged therefrom alter repeated passage between the milling couple therein until the particles of the colloid are disinte rated and dispersed therein to the desired egree. Thefirst step in said process is to heat in one of the containers 1 or 2 aforesaid, a sufficient quantity of oil to be used in such a single batch. The second step is to circulate the hot oil through the conduits and assageways of the apparatus to be traversed by the/colloid, by operating said pumps. The efl'ect of such circulation is to not only heat the apparatus to such temperature as to I batch to be progressed therethrough without solidification, but also dissolves out, into the oil, any waxy matter which has been deposited in the apparatus; second step; the hot oil having been deposited in one of said containers, the third step is to add thereto the other ingredients to form the desired batch of colloid which, of course, is

heated to the desired degree. The fourth step is to circulate the colloid through the mill until the particles and oil globules therein have beencomminuted and dispersed in the colloid to the desired degree.

Thereupon, the milled colloid may be withdrawn from the container 1 or 2 in which it permit the colloid At the conclusion of saidbe conveniently employed as above contem-- plated to control the conduits leading to and from said containers 1 and 2. However, it is obvious that said conduits may be other wise controlled.

I have found it desirable to provide means.

to vary the rate of rotation of the rotor from one thousand revolutions to more than twenty thousand revolutions per minute; and to vary the clearancebetween the milling surface of said rotor and the opposed surface of the stator-from .002 inch u lard, according to the materials in the colloid and the desired degree of comminution thereof.

Although I find it convenient to use the oil ingredient of a carbon do )0 colloid as the medium for preheating and cleansing the apparatus; my invention is not limited to colloidscontaining oil, but is applicable to colloids comprising other liquids which may be used for the heating medium, for instance, textile emulsions, (1 es and cements in which the principal liquit ingredient is water. In such cases the water or other liquid ingredient of the prospective colloid may be used as-the heating and cleansing medium.

Therefore, I do not desire to limit myself to the precise details of construction, arrangement or )rocedure above set forth, as it is obvious t at various modifications may be made therein without departing from the essential features of my invention, as defined in the appended claims.

I claim:

1. A process of preparing, in successive hatches, a colloidal composition, including oil and wax, which solidifies at atmospheric temperatures. which consists in charging a container with a suflieient quantity of oil for one batch; preheating said oil above atmospheric temperatures; progressing the hot oil irom said container to another container, through apparatus including a pressure pump. a rela tively rotary milling couple, an exhaust pump, and conduits connecting them, and

thereby preheating said apparatus to such temperature as to prevent solidification of such colloidal composition therein; retaining said hot oil in the apparatus while adding to said oil the other ingredients to form a single batch; and progressing said batch alternately from one of said containers to the other, through said apparatus, while thus heated, until the globules of oil and particles of other matter in said batch are comminuted and dispersed therein to the desired degree.

2. A process of preparing, in successive batches, a colloidal composition, including oil and wax, which solidifies at atmospheric temperatures, which consists in charging a container with a sufficient quantity of oil for one batch; preheating said oil above atmospheric temperatures; progressing the hot oil from said container to another container, through apparatus including a relatively rotary milling couple, and thereby preheating said apparatus to such temperature as to prevent solidification of such colloidal composition therein; retaining said hot oil in the apparatus while adding to said oil the other ingredients to form a single batch; and progressing said batch alternately from one of said containers to the other, through said ap paratus, while thus heated, until the particles of matter in said batch are comminuted and dispersed therein to the desired degree.

3. A process of preparing, in successive batches, a colloidal composition which solidifies at atmospheric temperatures, which consists in charging a container with a sufficient quantity of a liquid ingredient for one batch; preheating said liquid above atmospheric temperatures; progressing the hot liquid from said container to another container, through apparatus including a relatively rotary milling couple, and thereby preheating said apparatus to such temperature as to prevent solidification of such colloidal composition therein; retaining said hot liquid in the apparatus while adding to said liquid the other ingredients to form a single batch; and progressing said batch alter-.

nately from one of said containers to the other, through said apparatus, while thus heated, until the particles of matter in said batch are comminuted and dispersed therein to the desired degree.

4. A process of preparing, in successive batches, a colloidal composition, including liquid and solid matter, which consists in charging a container with a suflicient quantity of liquid for one batch; preheating said liquid; progressing the heated liquid through apparatus including a relatively rotary milling couple, and thereby preheating said apparatus; retaining said heated liquid in the apparatus While adding to said liquid the other ingredients to form a single batch; and progressing said batch alternately from one of said containers to the other, through said apparatus, while thus heated, until the particles of matter in said batch are comminuted and dispersed therein to the desired degree.

5. A process of preparing a colloidal composition, including liquid and other matter, which consists in preheating a liquid ingredient for said colloidal composition; progressing the heated liquid through apparatus including a relatively rotary milling couple, and thereby preheating said apparatus; retaining said heated liquid in the apparatus while adding to said liquid the other ingredients for the colloidal composition; and progressing said colloidal composition through said apparatus, until the particles of mattter are comminuted and dispersed in the colloidal composition to the desired degree.

In testimony whereof, I have hereunto signed my name at New York, New York,

this 23rd day of February, 1926.

HARoLD W. A. DIXON.

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