US415608A - Process of bleaching - Google Patents

Description

(No Model.) Y

L. Q. BRIN. PROCESSO? BLBAGHING.

No. 415,608. Y .Patented Nom-19, 1889.v

UNITED STATES VPATENT OFFICE.

LON QUEN"IN BRIN, OF PARIS, FRANCE, ASSIGNOR TO 'llIE yCO1\I'l`INE-I\TTAL OXYGEN COMPANY, (LIMITEDQ OF IVEUTMINSTER, ENGLAND- PROCESS OFBLEACHING.

SPECIFICATION forming part of Letters Patent No. 415,608, dated November 19, 1889.

APPHCHGOH 51e/d July 9, 1888. Serial No. 279,422. (No specimens.) Patented in England April 12, 1888, No. 5,458; in Germany May 24, 1888, No. 46,811, and in Austria-Hungary November l, 1888, No. 22,012 and Noi/10,071.

To @ZZ whom it may concern,.-`

Be it known that I, LoN QUENTIN BRTN, engineer and chemist, a citizen of the French Republic, residing at 7 Rue Gavarni, Paris, in the Republic of France, have invented certain Improvements in Bleaching, (for which Ihave obtained patents in Great Britain, No. 5,453, dated April 12, 1888; in Germany, No. 46,811, dated May 24, 1888, and in Austria-lfIungary, Io Nos. 22,012 and 40,071, dated November 1,

1888,) of which the following is a specification.

The said invention has for its object to provide a bleaching process which is more rapid than such operations as usually conducted, and in which economyin the bleaching agent is effected.

The said invention consists in the combined use for bleaching purposes of oxygen and 2o bleachingpowder, chlorine, or equivalent chlorous bleaching agent, it being found most advantageous, however, to employ bleachingpowder. The use of oxygen in connection with the bleaching powderor agent is for the purpose of economizing the latter, enabling the same result to be accolnplished with a great saving in the more expensive bleaching agent. From the use of oxygen,moreover, in the manner hereinafter described, it results 3o that the fibers of the material bleached are left in better condition than when the ordinary bleaching substances alone are employed.

Many attempts have heretofore been made to utilize the action of oxygen in bleaching fibrous and other substances; but these attempts have hitherto been unsuccessful, mainly, it is believed, because the conditions under which oxygen can be made to co-oper- 4o ate in producing a bleaching effect have not been sufficiently well understood. It has therefore been generally supposed and held by the best authorities on the subject that by the employment of oxygen gas in bleaching processes no oxidation of the fibers and consequent decolorization is effected thereby, but that the only effect of the use of oxygen (or air containing the same) has been a purely mechanical one. This is probably true in `respect of the processes in which it hashere- 5o tofore been attempted to employ oxygen. I have found, however, by careful experiments, jfirst on a small scale and afterward repeated lon a commercial scale with large quantities of fibrous material-such as paper-pulp-that 5 5 `by the use of oxygen (pure or practically pure) in the manner herein pointed out from twenty-five to thirty-five per cent. of the expensive chlorous bleaching agent may be saved. The oxygen when admitted in accord- 6o ance with this invention is found to be actually absorbed, and when the supplyof oxygenis properly regulated there is no excess -to pass off. This indicates that the natu-ral colori11g-matters present are removed by di- 65 rect oxidation of the fibers, and it is believed that such oxidation is not effected at a bound, but progresses by stages. The reactions that take place are obscure and complicated. My experiments indicate that while the original 7o coloring-matters are not acted on bythe gase` ous oxygen some of the intermediate products or unstable compounds are so acted upon and bleached by further oxidation when free oxygen is presented to them. 7 5

It has been proposed heretofore to force through a vat containing fibrous material. to be bleached and a chlorous bleaching agent a powerful current of air with the object of producing the ozone modification of oxygen 8o in presence of the material being bleached. Such process, however, would not increase the efficiency of the bleaching agent for the reason, among others, that the current of air necessarily carries off a comparatively large quantity of chlorine vapor, which loss is not compensated by any effect the oxygen of the air introduced might produce. The presence of any inert gas (as nitrogen) has not only the effect of carrying off portions of the valu- 9o able bleaching agent, but has the further effeet, as I have found, of interfering with the action of the oxygen that would otherwise take place, as above stated, in connection with the bleaching agent. Therefore to produce the saving above indicated and to obtain the most advantageous results it is necessary to use oxygen pure and without admlxture With other gases and to regulate the amount of the gas used so that there may be no excess passing off, and consequently no impoverishment of the bleaching solution.

rlhe proportions of materials ,employed will of course vary somewhat With the character of the substances bleached, and with other Variable conditions; but the following directions will serve to enable those skilled in the 1o art to carry out the invention so as to obtain good results. ln operating upon one ton of esparto grass, which ordinarily requires two hundred pounds of bleaching-powder, two hundred feet of oxygen were used, enabling me to dispense with from fifty to seventy pounds of bleaching-powder and resulting in a pulp of equally good color and brilliancy, and which yielded a paper of superior tensile strength.

The accompanying drawing illustrates in Vertical section an apparatus adapted forearrying out the operations according to this invention. l

i The vat, potcher, or other vessel a contains the material to be bleached and the bleaching solution, when this is used instead of a gas, and is provided with a roll or cylinder l), armed with projections on its periphery and adapted to be driven in the direction of arrow 0c by 3o any suitable motor. At one side of roll l) is a dam or obstruction c, to facilitate stirring and the continuous circulation of the mass, as Well as 'the mixing` therewith of the oxygen, which is admitted by a pipe CZ in front of the roll and perforated at the part that is Within the vessel. Pipe d is protected by a shield e. YThrough this pipe the oxygen is forced by any suitable forcing device at. just sufficient pressure to overcome the head of Water, so that it comes in contact with the matter to be bleached, and is thoroughly agitated therewith by the action of the roll b.

Having now fully described my said invention, what I claim, and desire to secure by Letters Patent, is-

l. The process of bleaching herein described, consisting in acting upon the material to be bleached With a chlorous bleaching agent, and While so acting introducing into the bath oxygen in regulated quantities and free from adinixture with other gases, substantially as set forth.

2. The process of bleaching brous and other substances by treating the same with a chlorous bleaching solution, and While agitating the mass introducing free oxygen in regulated quantities, substantially as set forth.

In testimony whereof I have signed my n ame to this specification in the presence of two subscribing witnesses.,

LEON QUENTIN BRIN.

Witnesses:

E. MULLINs, 13 Inrerness Terrace, l/V. London..

FRANK ScHLoEssER, Connaught Mansions, lTctofrict Street, Westnz/L'nsler.

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