DE189735C - - Google Patents

Description

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Erased on May 16, 1918

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IMPERIAL

PATENT OFFICE.

PATENT LETTERING

- ■ Jig 189735 CLASS 55 b. GROUP

ALVAR MÜNTZING in STOCKHOLM.

Patented in the German Empire on June 20, 1906.

In all previously used processes for the production of cellulose by boiling the Raw material is the raw material, e.g. B. wood, filled into the cooker in the crushed state. In the cookers, the whole amount of wood is used to clear the cellulose fibers, i. H. so to dissolve the rest z. B. encrusting constituents certain cooking liquor cooked until the filling as

ίο treated as finished applies. Here the Cooker either completely closed during cooking or with pipes be connected, which allow a circulation (possibly also a refreshment) of the cooking liquor.

However, since the chemicals used to prepare the cooking liquor, such as caustic alkalis, in connection with sodium sulphide or potassium sulphide, acid sulphurous acid salts etc. with continued action on the cellulose fibers also attack them, see above that they, especially at high temperature and strong pressure, are not only weakened, but also to be more or less dissolved, so has been the case with the previous cooking methods it cannot be avoided that at least some of the cellulose fibers are weakened and part of it was dissolved. As a result, the "yield" is neither so great was still of as good quality as it was theoretically could have been. The fact that what the wood As concerns, part of it is often more soluble and easier to cook than another at the same time material entering the cooker. For this reason, the addition of lye must be so strong and cooked with it until the wood or wood that is difficult to cook other raw material is certainly sufficiently dissolved and broken up. You can't do that avoid that the loose and easy-to-cook raw material in the cooker, such as * it is said that it is cooked too strongly, so that part of the fiber is attacked or completely dissolved will. Furthermore, it cannot always be avoided that part of the wood is more humid than someone else who is supposed to be cooked at the same time. As a result of the fact that the wetter Wood is harder to cook than dry, this results in the same ratio, as mentioned above.

To avoid these inconveniences, the new cooking method should be used during the cooking process the removal of the freed cellulose fibers immediately after their final treatment be made possible.

The new method is that the freed fibers immediately after their exposure with the circulating in a known manner Cooking liquor torn from the cooking vessel or vessels and put in a suitable one Apparatus to be collected for what purpose the cooker or the cooker in such open connection with the outer conduit that entrainment and separation the fibers can move unhindered. The cooking liquor, which by sufficiently strong Tubes is passed through is expedient

a so-called filter press, as used in the manufacture of sugar, kaolin and the like. to be used. Such apparatus, however, then become special for the present purpose customized. The: cellulose fibers remain in the apparatus. back while the outgoing Lye by any pump device in a known manner to the other end of the cooker is returned.

ίο Cooking takes place either in lying cylindrical boilers or in upright-standing boilers, the former rotating can be moved.

The two embodiments of the cooking appliances are shown in the drawing.

Fig. Ι illustrates the cooking apparatus in one embodiment.

A is the cylindrical cooker, which can be set in rotation by means of a transmission device below and which runs with the roller tracks B in appropriately designed wheels. A manhole for bringing in the wood is marked with C and the lye line from the boiler is marked with D.

E is a branch catcher, in which larger branches and wood that has not been divided are caught by a latticework. F denotes an apparatus, e.g. B. a filter press to separate the cellulose fiber from the liquor.

G is a pumping device, whereby the liquor coming from F is returned directly or through a heating device H to the cooker. If necessary, new cooking liquor can be fed in through the pipe K.

During the boiling and the lye circulation, the cooker will be faster enough Rotation kept so that the raw material for the cellulose in the boiler through Friction can excrete the cellulose fiber to the extent that it is finished.

Fig. 2 illustrates the apparatus in a second embodiment, wherein the circulation the lye and the excretion of the cellulose fiber take place in approximately the same way as in the previous case. The only difference is that the lye is from the lower end of the digester comes off and is fed back at the top of the digester. At this The cooker stands still while the lye is circulating. If so desired the cooker can be provided with a movement device such that the same can sometimes be set in rotation about a horizontal axis, however Of course, the caustic lines must be uncoupled and the cooker must be closed with taps got to.

In the cellulose fibers, which in one certain apparatus (filter press) are excreted, some of the lye remains, which washed out in an expedient manner and, if alkalis in any form at Cooking is cleaned in order to recycle the chemicals used in the liquor. Instead of the in This amount of lye removed during boiling can be done in a known manner and after new lye of suitable strength can be added to the lye during the to maintain a more uniform strength throughout the cooking time. You can also do that with Use stronger lye at the beginning of cooking or after reloading wood, than the clearing of the fiber generally requires.

In those cases where the fiber can be freed sufficiently without applying pressure, and can clean, the supply of new raw material can gradually during the Cooking happen. The horizontal digesters are then used during loading shut down. If steam pressure is required, two cookers are used alternately, see above that one can be cleaned and loaded with new wood, while the other is cooking. When the latter has progressed so far that a new load is required is required, the cooking liquor is passed from the latter cooker to the one which has previously been charged had been.

The new cooking process has the particular advantage that the wood is not chopped into chips must be, rather the wooden blocks or slats brought into the stove in such lengths as appropriate to the size of the stove and convenience. Besides the cost of hacking are saved, one avoids the considerable loss of wood that occurs when chopping arises, and also the shortening of fibers by the chopping knife.

When cooking with horizontal stoves using undivided wooden blocks or Lath wood, which lies horizontally in the cooker, will keep the cooker rotating so quickly, that the cellulose fibers are rubbed off the surfaces of the blocks or slats, to the extent that they are sufficiently cleared and cleaned for this purpose.

The new cooking process can of course also be used for raw materials other than wood be, in which case the arrangement or device of the digester may have to be adapted to the type of raw material.

Instead of uniting one apparatus of each type shown in the drawing several of these can of course be used at the same time. Likewise can also one or more of the apparatus, e.g. B. the branch catcher, omitted under favorable circumstances will. Instead of the suds heater

Steam could be directed into the stove or the stove could be heated in some other way will.

Claims (2)

Patent Claims: i. Process of making pulp by boiling wood at constant Circulation of the cooking liquor through the cooker and possible refreshment of the cooking liquor, characterized in that the freed fibers as they are freed with the flow the cooking liquor can be led out of the cooking vessel and collected. 2. Cooker for performing the method according to Patentnspruch 1, characterized in that an apparatus (z. B. a filter press F) for collecting the fibers "is switched on in the pipe (D) for the circulating liquor. 1 sheet of drawings.