US1638886A

US1638886A - Method of bleaching wood pulp

Info

Publication number: US1638886A
Application number: US10811A
Authority: US
Inventors: Frederick G Sherbondy; Max E Boehm
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-02-21
Filing date: 1925-02-21
Publication date: 1927-08-16
Anticipated expiration: 1944-08-16

Description

Aug. 16 1927.

1,638,886 F'. G'. SHERBONDY ET AL METHOD OF' BLEACHING WOOD PULP Filed Feb. 21. 1925 2 Sheets-Sheet 1 H H Hlllllllllmlpllm WWUHHUUI HHH Ilmlilllllm n 1,638,886 Away 15, 1927' F, G, sHERBONDY ET A'- METHOD 0F BLEACHING WOOD PULP Filed Feb. 21. 1925 2 Sheets-Sheet 2 lulerbo .7l/@wc :Boe/Uw,

Patented Aug. 16, y192,7.

UNITED STATES i l l 1,888,888 PATENT OFFICE.

FREDERICK e. sHnnBoNDY, or AKRON, OHIO, AND MAX n. Bonnin, or ArrLn'rON,

WISCONSIN. f -v METHOD Aor BLEACHING WOOD Prim.

f! i Application led February 21,11/925 Serial No. 10,811.

4The object of our invention .is to provide a novel apparatus and method for bleaching, under pressure, wood pulp at a highconsistency, the invention being adapted, however, for use'in'connection with the bleaching of `other materials.

'lore specifically, the method resides in agitating and mixing the stock, at high consistency, and under pressure, with the bleach liquor, in a closed container, Without the application of heat; and, by this cold bleaching, under pressure, of the stock, at a high consistency, a` much tougher grade of'work is secured than is possible in Ahot-bleaching,

" 'which has a tendency to weaken the fibres of the stock. Another advantage of this method of bleaching in a closed, air-tight container,- is that escape of chlorine gas is prevented, thereby economizing in the cost of practising the method.

YThe Aapparatus resides in a closed container or retort, which is constructed so as to be pressure tight -and thus retain all the chlorin gases, and whereby the pressure of the gases evolved'in the retort makes it possible, to secure a better penetration of the bleach liquor into the stock.' The invention also resides in providing the retort, inteniorly, with baffles, so arranged that it is possible to thoroughly mix the stock at a high consistency.

An apparatus capable of practising the method is disclosed in the accompanying drawings, in which like reference-characters denote corresponding structural parts in the several views. Briefly described:

Figure l is a view in side elevation of our retort or engine;

Figure 2 is a view in end elevation thereof;

Figure 3 .is a view in top plan of the retort removed from its supporting pillars; and

Figure 4r is a view in section, taken upon the plane of the section line l-h indicated in Fig. 1, looking in the direction ci the arrows shown in connection therewith.

Referring, now, in detail to the drawings:

l indicates, in general, our ,globe rotary bleaching engine, which i-s constructed pressure proof and air-tight, so as to prevent 'escape of chlorine gas in the operation thereof, and which is provided with a man-hole 2 tightly closed by a cover 3 when t-he engine is in operation,` and with a valve 4, said cover and valve being preferably disposed at da-metrica-lly-Opposite points on the engine.

The engine is also provided with

tru'nnions

5, 5, rotatably supported in bearings at the top of

pillars

6, 6. y

, Fast Aon one of said trunnions. is a gearwheel 7 meshing `with a gear-train driven from a suitable source of power, whereby the engine or retort may be revolved. at thespeed desired.

Interiorly, the globe l is provided with equidistantly spaced pairs of

wings

8, 8, each pair being, roughly, bow-shaped, as shown. These wings constitute agitators or baiiles, which agitate and mix the stock with the bleach liquor. Referring to the drawing it will be seen'that the wing-shaped ballles are not all arranged -alike,.but are so arranged that the point`or the apex of adjacent baffles point in opposite directions With respect to the direction of rotation, that is, one set of alternate ballles point yin the direction of rotation while the other set of bales point in the opposite direction to that of rotation. By the construction described, it iso possible to expeditiously mix stock, at high consistency, with the bleach liquor, and to carry on the bleaching operation under pressure.

This pressure may be gas evolved from the chlorine used in the bleaching liquor, or such pressure may be supplemented, as required, by other forms of gas, or by water, or by steam forced into the rotary bleaehelv or retort. The action of the apparatus is as follows:

The rotation of the globe tends to raise the pulp on the rip-turning side of the charnber and to cause it to flow back towards the lowerrnost point of the globe. This causes the pulp to move continuously in a rolling or as to'. cause alternate concentrating and spreading` of the flow. It will be seen that as a baille point-ing away from the direction of rotation passes through t-he stock, it will carry a portion of the mixture along in front of it, and as it begins its upward travel the sides of the baile form a pocket-like element and direct the flow towards the point Of the batile,'where it will pass over the upper edge in a concentrated stream. But with respect to an adjacent balle, the'sides will act as dellectors for the stream and will cause the stock to spread out and pass over sure, in a closed retort, there is no loss of the bleach liquor or gases, resulting in a substantial saving over customer methods :of bleaching in an open receptao e. Since the retort is pressure-proof, the gases generated in the bleaching operation are coninedjta d the pressure thereof makes it possible to 'get a better penetration of the" liquor into the q stock.

Having thus fully described our invention, what We claim as new and desire to secure by Letters-Patent of the United States is:

l. The method of bleaching pulp which consists in enclosing a mixture of pulp and bleaching liquor within a sealed spherical container, and agitating the mixture by subjecting it to alternate spreading and concentrating flow action. v

2. The metlr'ri'of bleaching pulp which consists in encl` sing a mixture of pulp and bleaching liquor within a sealed container, agitating the mixture by causing it to flow continuously in one direction with alternate spreading and concentrating action.

3. The method 4of bleaching pulp which consists in enclosing a mixture of pulp and bleaching liquor within a sealed spherical container, and agitating the mixture by subjecting it to a rolling flow towards a common point.

4. The method of bleaching pulp wliich consists in admitting a mixture of ulp and bleaching liquor to a spherical cham er, sealing the chamber, subjecting the mixture to pressure, agitating the mixture by rotating the chamber and causing the flow of the mixture to alternately s read and concentrate.

5. The method o bleaching pulp which consists in admitting a mixture of ulp and bleaching liquor to a spherical cham er,'seal' ing the chamber, subJecting the mixture to' pressure, agitating the mixture by rotating the chamber continuously in one direction and causing the flow of the mixture to alternately spread and concentrate.

v In testimony whereof, We affix our signatures.

FREDERICK G. sHERBoNDY. MAX E. Bo-EHM.