USRE1449E - Delphia - Google Patents

Description

PATENT OFFICE.

WILLIAM F. L DD, on N W YORK,N. Y., AND MoRRIsL. KEEN, or PHILA- DELPHIA, PA., ASSIGNEES, BY- MESNE ASSIGNMENTS, on CHAS. WATT AND HUGH BURGESS.

IMPROVED PROCESS'OF TREATING WOOD OR OTHER VEGETABLE SUBSTANCE IN THE MANUFACTUliE OF PAPER-PULP.

Specification forming part of Letters Patent No. 11,343, dated July 18, 1854; Reissue No. 608, dated October 5,

1858; Etntedated August 19, 1853; Reissue No. 1,449, da-ted Avril 1, 1863.

To all whom it may concern Be it known that CHARLES WATT and HUGH BURGESS, of London, England, did invent,

make, and apply to use certain Improvements in Pulping and Disintegrating Vv'ood and other Vegetable Substances, (for which Letters Patent were granted to them by Her Majesty the Queen of Great Britain, bearing date the 19th of August, 1853;) and we do hereby declare that the following is a full, clear, and exact de-' scription of said invention and of the mode of carrying out the same in practice.

The wood or vegetable substances upon which it is intended to operate by this process should first be reduced to fine shavings or cuttings. This may be done in any suitable machine. The shavings or cuttings of varying, with the nature of the vegetable substance being acted upon, to a strength of about 10. The varied nature of the vegetable substance to be operated upon is such that only general directions can be given for the strength of the alkali, or the degree of heat to be used, or the duration of the operation. Boiling in a solution of caustic alkali under pressure is of essential importance. By the words under pressure is meant a pressure at near or above 300 of Fahrenheits scale, which is the ordinary pressure used; but a heat and corresponding pressure of from 300 to 500 may be used, according to the nature of .the vegetable substance to be treated, whether resinous or non-resinous, or otherwise, and the time may be from four to twelve hours, -according to the nature of the substance. After the vegetable substance has been thus op- DIVISION. B. erated upon by caustic alkali under heatand pressure for the requisite time, as above described, it should be discharged from the boiler while under pressure into a tank or other reservoir with proper safety-valves and pipes for the discharge of the steam, and should be drawn, as Soon as the steam shall have escaped, into open vats, where it ca be operated upon 'in the next stage of the process; or it may be drawn directly into the vats from the boiler.

The vats which receive the wood shavings or cuttings, or other vegetable formed into pulp, should be constructed with suitable means of drainage. The alkaline solutions must then be removed from the pulp either by percolation and subsequent washing in the vats or by pressure in any conven ieut apparatus and subsequent washing. The mode by percolation has generally been found sufficient. The alkaline solutions thus obtained may be saved and evaporated down, and the residium burned in a furnace suitably constructed, so as to prepare the alkaline substances for use in a repetition of the same process. The alkaline solutions having been removed by percolation and washing or by pressure and washing, the wet mass of woody or vegetable pulp is nowto be exposed to the action of chlorine, or the compounds of chlorine with oxygen, for the purpose of bleaching it and preparing it for the manufacture of white paper. Brown, colored, or unbleached paper of a good quality can be produced from the pulp as soon as the alkalinesolutions are removed; but for the production of good white paper it is necessary to subject the pulp to the bleaching process. If the material used be wood or vegetable substance of anon-resinous nature, the pulp may be bleached by subjecting it to the action of chlorine in a gaseous form, or, which is preferable in this case, in an aqueous solution, in any of the common and well-knownmodes. If the wood or vegetable substance be of a alkaline solutions should be removed by the mode above described, and the pulpy mass should be exposed to the "action of chlorine or substances being resinous nature, the V its compounds with oxygen This may be done by placing the pulpy mass of woody or vegetable substance on racks or drawers arranged in a chamber, and applying chlorine or its compounds with oxygen in the gaseous form, which with resinous substances is preferable to the aqueous solution, until the mass is sufiiciently acted upon. The mass must then be again well washed and treated with a weak solution of caustic alkali, (warm preferred,) which changes the red color to a dark brown. The alkaline solutionshould then be removed by Washing, and the resulting gray pulp may be bleached by any ordinary method of bleaching.

What we claim as the invention of CHARLES WATT and HUGH BURGESS is.

1. The process of treating wood or other Vegetable substance by boiling in an alkali '2 d 7 I 1,449 7 h under pressure, as a process or preparatory process for making pulp for the manufacture of paper from such woods or other vegetable substances, substantially as described,

2. The process of treating resinous woods by boiling in an alkali under pressure, and treating the product with chlorine and its compounds with oxygen for making white pulp for the manufacture of paper from such woods, substantially as described.

MoRRIsL. KEEN. (WILLIAM F. LADD.

Witnesses to \V. F. Ladd: J ONATHAN S. ODELL, SAMUEL OoLEs.

. \Vitness'es to M. L. Keen:

GEo. O. WARD, PATRICK WARD.