IMPROVED METHODS OR PROCESSES OF, AND APPARATUS FOR, IMPREGNATING MINERAL SUBSTANCES OR COMPOUNDS WITH BITUMINOUS PRODUCTS
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine Lake,
"
& Co., Patent Agents, Southampton Buildings, London for an invention of
IMPROVED METHODS OR PROCESSES OF, AND APPARATUS FOR, IMPREGNATING
MINERAL SUBSTANCES OR COMPOUNDS WITH BITUMINOUS PRODUCTS"
A. com-
munication from abroad by Richard Michelet and Louis Tescher, both of
Berlin, Prussia,
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 23rd August 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, "IMPROVED METHODS OR PROCESSES OF, AND
APPARATUS FOR, IMPREGNATING MINERAL SUBSTANCES OR COMPOUNDS WITH
BITUMINOUS PRODUCTS A communication from abroad by Richard Michelet
and Louis Tescher, both of Berlin, Prussia
"
This Invention relates to improved methods or processes of impregnating more
or less porous stones, bricks, or other articles made from native or artificially
prepared minerals, with bituminous substances for the purpose of producing an
exceedingly durable material for paving, building and other purposes, and to
apparatus for performing the same.
The said methods or processes are applicable to the impregnation, both of native
porous stones, such as native sand-stone, lime-stone, chalk, gypsum and the like,
and of artificially prepared stones, such as clay-bricks, clay-pipes, cement-stones,
tiles, and the like, or of porous stones or moulded pieces of any mineral com-
position.
The said Invention consists essentially in subjecting the stones or moulded pieces
to be impregnated with bituminous products, to the action of intense heat, vacuum,
and pressure. For this purpose the stones or moulded pieces, after they have been

page_text: previously dried or burned according to requirements, so as to attain the requisite
degree of consistency, and to have, as far as possible, all moisture removed out of
them, are placed in a receptacle of any suitable construction provided with an
air-tight cover. The said receptacle having been closed so as to be perfectly
air-tight, is subjected to the action of a temperature of about four hundred degrees
(Fahrenheit) more or less, as the temperature, in a measure, depends upon the
character and quality of the bitumen used, and also on the composition of the
stones or minerals to be impregnated; but in every instance the temperature to
which the stones, bricks, or other articles are subjected whilst in the said receptacle,
must be above three hundred and ten degrees (Fahrenheit). After heating the
stones, bricks, or other pieces, as described, the air is exhausted from the said
receptacle so as to produce a vacuum within the same.
The object of this vacuum is to fully open the pores of the porous minerals to be
impregnated, and to remove every remaining trace of moisture from the same.
The tendency of the stones or pieces to absorb and retain in themselves the
bituminous substances, which are now allowed to enter the receptacle, is thereby
greatly increased. In order to cause the bitumen to thoroughly penetrate the
stones, the latter are now subjected to a pressure of two, or more atmospheres.
The stones, or other pieces, having thus been thoroughly saturated with bitumen
within a comparatively short time, are allowed to remain in the receptacle for a
further period, the surplus bitumen having been drawn off, the original temperature
of four hundred degrees, more or less, being maintained within the receptacle
during the whole operation. The impregnated minerals are then taken out of the
receptacle and when cool are ready for use.
The action of a higher temperature than three hundred and ten degrees, in
combination with a pressure above that of the atmosphere, causes the bitumen to
so combine with the impregnated stone, as to render even the influence of very
high temperatures incapable of removing it again, because the bitumen in con-
sequence of the above described treatment, is not merely drawn in by the stones,
but combines more or less with the clay, lime, cement or the like, of which the
said stones or moulded pieces may consist, according to the character of the
material. In some cases the employment of a vacuum may be dispensed with,
and the bitumen pressed directly into the stones, heated as above described.
The bituminous products suitable for these processes are asphaltum, coal-tar,
pitch, ozokerite, residues of petroleum, or the like.
The apparatus made according to the said invention is illustrated in the
accompanying drawing, in which,
Figure 1 is a front view, partly in section, of the said apparatus.
Figure 2 is a side elevation, and,
Figure 3 is a plan, partly in section, of the same.
Figure 4 is an end elevation of a truck on which the stones, bricks, or other
moulded pieces to be impregnated, are placed in the receptacle.
Like letters indicate corresponding parts throughout the drawing.
a is a furnace; c the boiler for containing the bituminous substances; e the
receptacle into which the stones or the like to be impregnated are placed;
b, b, and d, d', are dampers for closing the flues of the boiler c and the receptacle e
respectively; f is the flue leading to the chimney; g and h are pipes connecting
the boiler c with the receptacle e; i is an aperture (generally closed by a cover)
for conveying the bitumen into the boiler c; is an air-pump, connected with the
receptacle e by means of the pipe k, and provided with the three-way cocks m
and m³, for the purpose of rarifying and compressing the air in the said receptacle;
n (Figures 2 and 4) is a truck for conveying the stones and other articles to be
impregnated within the receptacle e. The receptacle e is closed in front by a
removable cover; a crane or other suitable means is provided for the purpose of
facilitating the handling of the said cover which latter is provided with a
thermometer, and vacuum and pressure gauges.

page_text: The operation is as follows:-The slides b' and d are closed so as to allow the
heated gases from the furnace to heat the boiler c. The truck n being loaded with
stones, bricks, or other mineral pieces, is pushed into the receptacle e, the latter is
then closed by means of its cover, so as to be perfectly air-tight. The slides b¹ and d
are now opened, so as to allow the heated gases to heat the receptacle e to a degree
as above described. As complete a vacuum as possible is then produced in the
receptacle e by means of the air-pump, and for the purpose above mentioned; the
valve p of the pipe h is now opened so as to allow the bitumen which is in a
heated condition in the boiler c to be drawn into the receptacle e after which, the
valve p and the slides band d¹ are closed.
The three-way cocks of the air-pump then being reversed, the requisite pressure
herein before referred to is created within the receptacle e and the bitumen forced
into the open pores of the stones, bricks or other pieces. A thorough impregnation
is thus effected within about two hours more or less (depending on the thickness
of the stones to be impregnated), after the lapse of which time the cock of the
pipe g is opened and the surplus bitumen remaining in the receptacle e is forced
back again into the boiler c by means of the pressure prevailing in the receptacle e.
Any sedimentary matter remaining in the receptacle e is conducted, through the
pipe k, to a suitable reservoir by opening the valve o, in consequence of which the
normal atmospheric pressure is restored in the receptacle e. The cover is then
removed from the latter and the truck taken out. Another loaded truck is then
pushed in and the process repeated.
Having thus fully described the said invention as communicated to me by my
foreign correspondents, and the manner of performing the same, I wish it understood
that I am aware that, heretofore, clay-bricks and the like have been impregnated
with bituminous substances by boiling them in the latter for a certain length of
time; I am also aware of the previous employment of a vacuum and subsequent
pressure for impregnating, for instance, wooden sleepers for railroad purposes; I do
not therefore claim broadly the treatment of stones with bitumen, nor the use of a
vacuum and pressure for the purpose of such impregnation. I also wish it
understood that I do not confine myself to the construction of the apparatus as
herein before described, since the same may be varied greatly, and still be suitable
for the said purpose, but I claim,
First. The method or process of impregnating with bituminous substances,
native or artificial porous stones, or moulded mineral pieces or articles, by heating
them within a closed receptacle to a temperature of more than three hundred
and ten degrees (Fahrenheit) and then, by means of compressed air or other
gases, forcing the bitumen into the stones or other mineral articles, substantially
as described
Second. The method or process of impregnating with bituminous substances,
native or artificial porous stones, or moulded mineral pieces or articles, by heating
them within a closed receptacle, to a temperature of more than three hundred and
ten degrees (Fahrenheit) then creating a vacuum in the said receptacle containing
the stones or other mineral articles, and then, by means of compressed air or
other gases, forcing the bitumen into the said stones or other mineral articles,
substantially as set forth.
Third. In an apparatus for impregnating with bituminous substances, stones,
bricks, or other mineral articles, by means of the combined action of intense heat,
and pressure, the combination, with the air-tight impregnating receptacle e, of the
boiler c in which the bituminous substances are heated, the pipe h for conveying
the bitumen from the boiler c into the receptacle e, the pipe g for conveying the
surplus bitumen from the receptacle e into the boiler c, the air-pump 7 provided
with the three-way cocks m, m¹, and conduit-pipe k, the dampers b, b', and d, d',
for alternately directing the heated gases from the furnace to the boiler c and to
the receptacle e, and suitable apparatus for facilitating the easy removal of the

page_text: closing cover for the purpose of pushing in or taking out the truck n, all
substantially as herein described, and for the purpose specified.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this twenty third day of August in the year of our Lord One
thousand eight hundred and eighty two.
ME DART T ATOT