Improved Process for Making Cement or Cement Mortar.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improved Process for Making Cement or Cement Mortar.
I, OTTO BökleN, of Lauffen, on the Neckar, Wirtemberg, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
Cement consists of numerous particles of dissimilar composition essentially of
two groups, one of which is a glass like silicate and the other approximates to lime
powder.
In preparing the cement, a lime lye or solution is formed by the combination of
the water with the lime powder, in which lye the glass like silicate should be
dissolved. The more completely this dissolving takes place, the more perfect
becomes the subsequent hardening so long as the chemical composition of the cement
is a correct one.
In all the methods hitherto employed for preparing cement, the complete
dissolving of the silicate in the lime lye is not even approximately attained, and
the consequences of this are the numerous well known bad properties of cement such,
for instance, as cracking, sweating, nitrification, and many others.
By employing my improved process, the silicate is completely dissolved and the
cement is thereby properly prepared.
This improved process consists mainly in exposing the moistened cement mingled
with sand or other mixing material, in other words the cement mortar, on the one
hand to a high pressure, and simultaneously the separate grains of the game to a
lateral frictional movement. By a single application of this treatment, by means
of pressure and lateral friction, a portion of the cement, and by repeated applications
the whole mass of the cement, is dissolved, which is shown by the surplus grey
liquid gradually losing its rough feeling.
The cement mortar is set in motion at each pressure, whereby the lateral adjust-
ment becomes constantly smaller with the increasing compression of the cement.
Already, with the first strong pressure, the volume diminishes and the mortar is
compressed into a tough mass which is erroneously regarded by all practical
people as the commencement of the setting, which latter is, however, as a matter of
fact, only initiated by the dissolution of the silicates in the lye.
A strong pressure, together with a simultaneous lateral displacement of the
cement particles, may be produced in very many ways, for instance, in any of the
following ways:-
1. A vessel open at the top, which serves as a mould, is well filled with cement
mortar and a heavy roller moved backwards and forwards over it. The roller
penetrates into the soft mass and pushes a portion of it in front of it to one side or
the other according to the direction of the roller.
2. The pan of a mill, with vertical stones is filled with cement mortar and
the stones set in operation, the action being the same as in the first named case.
3. A vessel, open at the top and filled with cement mortar, may be placed under
the pressure plate of a press and subjected to the pressure of the latter, whilst the
lateral displacement of the cement mortar particles may be caused by-
a. An inclined and changeable direction of the pressure of the plate of the
press:
b. Giving the working side of the plate of the press a wavy, ridged or jagged
form, so that, at each application of the pressure, elevations and depressions
result in the surface of the mortar, whilst care must be taken that, at each
adjustment of the plate of the press, the ridges of the mortar and those of
the plate come each time in contact:

page_text: c. Giving the bottom of the vessel a wavy, ridged or rugged form, so that the
mortar, when pressed into the strongly conical depressions of the same,. is
squeezed together sideways.
4. The mortar may be pounded with hammers, and, in case they are operated
mechanically, the hammers are set obliquely or have an irregular course and
strike a different place at each blow. In the case of manual hammers, the
lateral motion is produced by the skilful handling of the hammer on the part of
the workman, and, in this mode of operating, it is necessary to give the bottom of
the vessel the form described in paragraph 3.
5. By means of crushing apparatus, such as stone breakers, roller mills and the
like.
In consequence of the above named vigorous treatment of the cement mortar, it
casily may happen that the mixing material, such, for instance, as grains of sand,
but more particularly pumice stones, pebbles or the like, may become broken
up. In such case, the mortar, after having been treated in the manner herein-
before described for this process, is placed a second time in the mixing machine,
or thoroughly mixed with a shovel by hand, in order to allow the freshly broken
surfaces to be wet by the cement solution. It is then easily either thrown into
the mould, or used for building purposes as toughened prepared cement.
There is no danger of premature hardening, in the cement which has been so
energetically treated by my process, as the hardening only commences in about two
hours' time and this time fully suffices for the thorough treatment of the material
by this process.
The weather-resisting capabilities, firmness and even resistance to fire in cementing
performed by my process are essentially greater than in works executed with cement
formed according to previously known methods.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
An improved process for making cement or cement mortar, characterised by the
energetic, mechanical treatment of the cement mortar, by subjecting it to alternate
strong pressure with a simultaneous lateral displacement of the mortar particles,
which may be done by means of rollers travelling backwards and forwards, roller
mills, pug mills, stamps, squeezing mechanisms, stone breakers, presses with obliquely
moving pressure plates, or with pressure plates having wavy, ridged or jagged
shaped under sides, which, at each pressure, alter their position, and further,
by means of a cement mortar holder having a jagged, ridged or wavy shaped
bottom, as well as by means of hand hammers, substantially as hereinbefore
described.
Dated this 2nd day of November 1892.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.