US1406938A

US1406938A - Method for producing wood flour

Info

Publication number: US1406938A
Application number: US358199A
Authority: US
Inventors: John J Cunningham
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-02-12
Filing date: 1920-02-12
Publication date: 1922-02-14
Anticipated expiration: 1939-02-14

Description

PATENT OFFICE.

JOHN J.CUNNINGHAM, OF GLENS FALLS, NEW YORK.

METHOD FOR PRODUCING WOOD FLOUR No Drawing.

To all whom it may concern:

Be it known that 1, JOHN J. CUNNING- HAM, a citizen of the United States, and a resident of Glens Falls, in the county of Warren and State of New York, have invented a new and Improved Method for Producing Wood Flour, of which the following is a full, clear, and exact descriptlon.

The invention relates to wood flour such as is used in the manufacture of phonograph records and other articles.

The object of the invention is to provide a new and improved method for producing wood flour from raw sawdust in an exceedingly economical manner.

The method consists essentially in screening raw sawdust, grinding the screened sawdust under development of heat to vaporize the moisture contained in the raw sawdust, separatin the vapors and the reduced sawdust, and bolting the sawdust to separate the coarse sawdust from the wood flour.

In order to carry this method into effect, I proceed in detail as follows: The raw sawdust as received from a saw mill, pulp mill or other plant and forming practically a valueless by-product, is passed over screens of a proper mesh to screen the sawdust from chips, pieces of bark and similar larger pieces. The screened raw sawdust is next passed in close proximity to a large magnet for the purpose of attracting metallic ob jects such as nails,'points of saw teeth and the like, to completely free the screened sawdust of the metal pieces. The screened raw sawdust is next reduced by grinding it in a grinding mill of the flour mill type, having a fixed and a rotating stone provided on their opposite faces with the usual grooves or channels. By subjecting the raw sawdust to the grinding action between the mill stones suflicient heat'is generated by the contact of the raw sawdust with the stones to vaporize the moisture contained in the sawdust. the grinding stones to draw the ground sawdust and the vapor from the grinding mill, and then the reduced sawdust and the vapor are blown by the suction fans into cyclones or dust collectors, usually located on the roof of the lant The v p s and he air Specification of Letters Patent.

Suction fans are installed adjacent Patented Feb. 14, 1922.

Application filed February 12, 1920. Serial No. 358,199.

drawn in by the suction fans pass out through the exhaust pipe on top of the cyclone, while the reduced and dry sawdust drops down into a pipe which connects the bottom of the cyclone with a bolting machine having screens of bolting silk and similar to the bolts used in the manufacture of flour from cereals. By subjecting the sawdust to the bolting action, the coarse particles of the sawdust are separated from the wood flour and the latter is now conveyed to a hydraulic press and formed under very heavy pressure into a bale having a burlap cover and weighing approximately 350 lbs. The coarse sawdust separated from the wood flour during the bolting operation is returned to the grinding mill to be reground into wood flour with the raw sawdust as above described.

It is understood that by vaporizing the moisture contained in the raw sawdust during the grinding action, the sawdust freed of the moisture is very finely comminuted by the rinding stones to form wood flour of a higi grade.

It will be noticed that by the arrangement described the sawdust is completely used up and formed into wood flour and the latter on account of being deprived of its moisture is in condition for forming one of the constituents of a composition of which phonograph records and other articles are'made.

It will further be noticed that it is very essential that metallic articles are removed from the raw sawdust as otherwise the wood flour is impure and the mill stones are liable to be injured by contact with the metallic substances.

It is understood that in the manufacture of wood flour as heretofore practiced it has been customary to grind pieces of wood into flour, but these pieces of wood had to be prepared especially for grinding, and hence the cost of the production of wood flour was considerable and very much higher than wood flour made from raw sawdust by the method above described. 1

From the foregoing it will be seen that by the process described, ordinary raw sawdust, which forms a practically valueless byproduct in saw mills, pulp mills and similar plants, is converted into a valuable wood flour and at comparatively little expense.

Having thus described my invention, I duced saw dust and vapors to a blast of air claim as new and desire to secure by Letters to force them into an elevated separator to 10 Patent i separate the vapors from the reduced saw The herein described method of producing dust, and delivering the saw dust to a b0lt- Wood flour, consisting in screening raw saw ing cloth by gravity, whereby the saw dust dust, grinding the saw dust under the deisthoroughlydried before being bolted so as velopment of heat to vaporize the moisture to insure the pro er boltin of the same. contained in the saw dust, subjecting the re- 1 o JoiiN J. GIfNNINGHAM.