US1587799A - Process for the production of wood pulp - Google Patents

Description

Patented June 8, 1926..

UNITED STATES PATENT OFFICE.

PROCESS FOR THE IRODUCTION OF WOOD PULP.

ll'o Drawing. Application filed Iune'20, 1523, Serial 110,648,707. Renewed November 11,1925.

The present invention relates to im rovements 1n the process of making woo and has particular reference to wood pulp -'used in the manufacture of light paper such as is usedin the newspa er business.

although not necessarily con ned to that purpose. Wood pulp 'of this character is commonly produced at the present time by grinding suitable blocks of wood. A rotatmg grindstone is'usuallyemployed and pre j ljogks to further treatment whereby they are separated into fibers which latter form the pulp without being cut into small particles. The wood pulpthus obtained is of considerably better quality than wood pulp obtained by grinding action and requires the addition of considerably less sulphide pulp for roducing a suitable mixture for the pro notion of paper. Other advantages" of my process will appear as the specification proceeds. I

In its preferred form my process em- 80 braces the following steps. Pieces of wood of any suitable form are fed into a machine known as a chipper consisting essentially of a plurality of rotary knife blades mounted axially in spaced relation, and are all cut across the grain into blocks of comparativelyshort length. say three-fourths of an inch.' These blocks are passed through a crusher or wood hog with the result that the blocks are separated into slivers of the same 40 length and preferably of the thickness of a match. To facilitate the further breaking up of these slivers it is advisable to pass the same through a pair of rollers whereby the slivers are flattened. From the rollers, or if none are used, from thecrusher the slivers are fed into a beater which separates the slivers, into fibers in the presence of water. The use of hot water in the beater is preferred to cold water. The-pulp propulp- -duced by this process may be further sub- 5 jected totreatment in refiners or brushers.

The advantages of my process are apparent; in the first place any waste Wood may be used while in the grinding process" it is necessary to use pieces of wood of certain dimensions for conveniently handling the same. A comparatively small amount of water" 's necessary while the grindstone has tobe flushed continuously to wash away the ground pulp.- There is a. considerno able saving in power since the wood'instead of being attacked at the line of highest resistance as in the grinding process is separated along the lines of least resistance.

The product is superior in so. far as the 65 fibers inthe final process inter-twine and exercise a binding action as distinguished from the ground wood. in which the pulp is held together by cohesion only. As 'a further advantage it should be mentioned that m process requires less skillful handling t an the grinding process in which latter a highly skilled mechanic has to main tain close watch continuously because it is necessary that the surface of the stone be maintainedjust right, with the grain on the sameneither too-sharp and deeo nor too dull and shallow. It is also necessary in th rindin process to exert an even pressure since too strong a pressure will cause too much friction and produce a burning action while lack'of pressure renders the operation inefficient. The-single steps of my'process and the handling of the achines for carrying out the same are simple as to require. little expert super; vision. I

I claim: The process of making woodpulp which consists in cutting pieces of wood across the grain into comparatively short blocks in crushin the blocks to. produce slivers substantialTy of the thickness of a match,'in rolling the slivers for flattening the same and in beating the slivers thus obtained into i pulp in the presence of Waiter.

HENRY FRANCIS JOSEPH Permian