IMPROVEMENTS IN THE MEANS OR METHOD OF AND PROCESS FOR PROTECTING AND PRESERVING WOOD
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Lorentz Albert Groth at the Office
of the Commissioners of Patents on the 2nd October 1880. A communication
from abroad by Albrecht Edward Barthel, of Detroit, in the County of Wayne
and State of Michigan, United States of America.
LORENTZ ALBERT GROTH, K.G.V., Civil Engineer and Proprietor of the Scandi-
navian Patent Office, under the Firm of L. A. Groth & Co., 97, Finsbury Pavement,
and 20, Forhaabningsholins Allee, Copenhagen. IMPROVEMENTS IN THE MEANS
OR METHOD OF AND PROCESS FOR PROTECTING AND PRESERVING WOOD." A oom-
munication from abroad by Albrecht Edward Barthel, of Detroit, in the County
of Wayne and State of Michigan, United States of America.
This Invention relates to an improved process of treating wood to prevent the
decay of the same and render it capable of resisting in a higher degree atmospheric
influences and other destructive agencies.
The Invention consists in treating the wood first with a solution of sulphate of
soda or magnesia, and then with a solution of chloride of barium, either after the
wood has been exposed to steaming or without steaming the same.
In the methods heretofore employed for preserving wood the chemicals by which
the wood has been impregnated have been more or less expensive, so that their
application has been necessarily limited. I have discovered that by the employ-
ment of solutions of sulphate of soda or magnesia and chloride of barium not only
a very effective preservative action is exerted upon the wood by the formation of
sulphate of baryta in the cellular tissues of the same, but moreover, by the presence
of the insoluble salts of chloride of sodium or magnesium the wood is protected
against fire, it being only charred thereby.
The chemicals employed are furthermore less expensive than those heretofore
used for impregnating purposes, which is a point of great importance, as thereby
the application of the process can be greatly extended.
In carrying my Invention into practice the wood may be first exposed to the
action of steam in a closed chamber to drive off the sap, moisture, and other matters.
After steaming a vacuum is created in the said chamber by means of an air pump.
The wood is then charged with a solution of sulphate of soda or magnesia, about
two pounds of either salt being dissolved in about 100 pounds of water.
The surplus liquid is discharged from the chamber, and then a solution of

page_text: chloride of barium forced or charged into the wood. The proportion of chloride
of barium is about two thirds by weight of that of the sulphate of soda or
magnesia for 100 pounds of water.
In treating large timbers, such as piles and pieces for docks, ships, and similar
structures, it would be inconvenient to subject them to the action of steam in a
chamber. In these cases the solutions are charged one after the other by hydrostatic
pressure by any approved apparatus devised for this purpose.
By the successive treatment of the wood with solutions of sulphate of soda or
magnesia and chloride of barium, with or without steaming, a decomposition of the
salts takes place in the tissues of the wood, and the insoluble salts of sulphate of
baryta and chloride of sodium or magnesium are deposited therein. These are
active agents to resist the decaying influences of the atmosphere, moisture, or
parasites. These insoluble salts serve not only as preserving agents, but as they
fill the tissues of the wood, also as a protection against destruction by fire, as the
wood can only be charred but not be burned with flame.