US2195680A - Apparatus for continuous treatment of wood pulp, cellulose, and similar material with bleaching liquid, alkali, or other chemicals - Google Patents

Description

,19s.ss0 AND SIMILAR P 1940. .1. c. F. c. RICHTER APPARATUS FOR CONTINUOUS TREATMENT OF WOOD PULP, CELLULOSE,

MATERIAL WITH BLEACHING LIQUID, AIJKALI, OR OTHER CHEMICALS l, 1936 2 Sheets-Sheet 1 a/MWm:

a f M n & J

Filed Dec.

April 1940. J. c. F. c. RICHTER 2.195.680

OUS TREATMENT OF WOOD PULP, CELLULQSE, AND SIMILAR CHEMICALS 2 Sbeets-Shee't 2 APPARATUS FOR CONTINU MATERIAL WITH BLEACHING LIQUID, ALKALI, OR OTHER EIgIJ Filed Dec.

Patented Apr. 2, 1940 v UNITED, STATES PATENT OFFICE Johan. Christofler Fredrik Cari Richter, Oslo,

Norway, assignor to Aktiebolaget Kamyr, Oslo Norway Application December 1, 1938, Serial No. 113,722 In Sweden December 9, 1985 2 Claims.

The present invention has for its object an apparatus for continuous treatment of wood pulp, cellulose and similar material, and the purpose of the invention is to provide an apparatus of 5 this type, in which the treatment can take place continuously without the necessity of conveyors, scrapers, stirring devices or similar movable parts in the apparatus. Particularly the invention relates to the treatment of stock having a medium consistency, i. e., from 5 to 12 or 14% dry material.

In accordance with the invention, the apparatus comprises a U-shaped channel having two vertical or inclined sections interconnected at the 15 bottom with a curved section of substantially the same cross section.

The material to be treated is introduced at the top of one channel after having been mixed with v the necessary chemicals, and the material then passes through the whole U-shaped channel, rising in the other section of the channel to a level which is dependent on the consistency of the material. v The channel section in which the material moves upwards is provided with an overflow, which maybe adjustable, as well as with a device for supplying liquid-for continuously removing material which has passed downwards through the first sectionof the U-shaped channel, and 80 upwards through the second section.

Some preferred embodiments of the invention are diagrammatically illustrated on the drawings. Figures 1 and 2 are diagrammatlcal cross sections of two different forms, whereas Figures 3 88 and 4 show cross section and plan view of a third embodiment. In accordance with the embodiment illustrated on Figure l, I is a mixing device of suitable construction for mixing the material with the chem- 40 icals with which it is to be treated. I and 3 are two channels, which may have circular or polygonal cross section and which are interconnected at their lower ends by means of a curved channel having the same cross section. The mixture 45 of material and chemicals is continuously supplied at the top of channel 2 and let out continuously at an overflow 4 in the side wall of channel 3 I Inthe upper part of channel3 there is located a water supply tube 5. From the overl0 flow the material passes into a storing tank 6, the object of which is to equalize the variations in the flow" of material which may occur owing to variations in the velocity of the mass passing through the channel. It In accordance with the form illustrated on Figure 2, the two parts 2 and 3 of the U-shaped channel are spaced from each other in order to obtain the smoothest possible passage through the apparatus, whereby it is obtained that the difference of level in the two passages may be kept low.

In accordance with the embodiment illustrated on Figure 2 the adjustable overflow 4 opens into the space between channels 2 and 3, in which the storing tank is located. The two channels 2, 3 need not necessarily be perpendicular, but may also be inclined at a certain angle, provided the angle of inclination is sumciently big to allow for automatic adjustment of the difference in level between the material in the two sections of the channel irrespective of the friction during the movement of the material through the apparatus.

In accordance with the form illustrated on Figures 3 and 4 there is provided at the top of channel 2 a pump 8 for thick pulp, this pump providing an additional pressure, which is in some cases necessary with highly concentrated material in case the static pressure difference between the two parts of the channel should not be suflicient.

The material may be supplied to channel 2 either through pump 8 or through an ordinary I filling opening 9.

Instead of the adjustable overflow 4 there is illustrated another type comprising a grid or screen, through which the material is removed that the cross section of the channel is large and other section being provided at the side facing the first section with an overflow for continuously removing the material treated,jsaid overflow being located substantially below the top level in said first section, a. storing tank for the treated material formed by and being located in the space between the twosections of the U-shaped channel.

- 2. An apparatus for the continuous treatment of wood pulp, cellulose and the like with chemicals, such as bleaching liquid, alkali or the like, comprising a substantially vertical U-shaped channel having a large, substantially uniform '2 n I f 1 2,195,680.

unobstructed cross section, the inner walls of said channel forming a storing tankior the treated material, one section of said channel be- 1 ing provided at the top with means for supplying material and chemicals and the other section being provided at a lower level with an overflow directed so as to empty into said tank whereby the material being treated may flow by gravity from saidrneans for supplying material to said

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