An Improved Process for the Production of Building Stones, Bricks, and like Articles.
Year: 1899

page_text: Date of Application, 23rd Jan., 1899
Complete Specification Left, 11th May, 1899-Accepted, 5th Aug., 1899
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Building Stones, Bricks,
and like Articles.
I, HUGO WERTIIS, of 41, Aldersgate Street, in the City of London, Merchant,
(being a communication from abroad by Peter Kleber, formerly of 64, Trierer-
Allesstrasse, Malatatt-Burbach, Rhine Province, in the Kingdom of Prussia,
Manufacturer, and now of 9, Binger Strasse, Mayence, in the Grand Duchy of
Hesse, in the Kingdom of Prussia) do hereby declare the nature of this invention
to be as follows:―
This invention relates to an improved process for the manufacture of building
stones and bricks by the employment of a mixture of sand and lime, and the
invention has for its object to produce such artificial stones and bricks of a better
quality by a simpler, shorter and less expensive process than those known.
The object of the applicant's invention is to effect slaking of the lime without
using water in any appreciable excess thus rendering any prolonged or severe
drying operation unnecessary and to bring about the setting of the material
before treating it, for the purpose of hardening it, with high pressure steam.
This object is attained by carrying out the slaking operation in successive stages
and subsequently completing the manufacture of the stone in the manner herein.
after described.
In carrying the invention into effect fine moist sand or quartz is mixed with
burnt and ground lime in the proportion of 1 of lime to from 8 to 15 parts by
weight of moist sand and the sand and lime are intimately and thoroughly mixed
together within a mixing machine of any ordinary construction. By the intimate
and thorough admixture in the mixing machine of the moist sand and lime, the
lime becomes partially slaked owing to the presence of moisture in the sand, great
heat is developed and the mixture becomes a fine powder. The mixture of sand
and lime is then conveyed from the outlet of the first mixing machine to the
inlet hopper of a second mixing machine where, however, it is caused to remain
for from one half hour to one hour so that it may become a fine dry powder in
which the whole of the moisture originally existing in the sand is completely used
in chemical combination to produce the slaking of part of the lime. On this treat.
ment the mass increases about 1/5th of its previous volume and the heat occasioned
in the partial slaking effects the formation of lime silicates so that to some small
degree the chemical action is similar to that effected on the subsequent treatment
by steam. The mixture is then passed into the second mixing machine where a
quantity of water is added by means of a sprinkler or other suitable jet, just
sufficient and no more than sufficient to effect the complete slaking of the whole
of the lime remaining unslaked. The quantity of water required for the purpose
will depend in part upon the degree of moisture of the moist sand employed in
the first mixing machine.
The treatment of the sand and lime, whereby a fine dry powder is first produced
and then afterwards final and complete slaking, enables the mixture to be effected

page_text: with a less expenditure of power than would be the case if the sand and the lime
were sufficiently wetted to form a plastic mass in the first instance, while the
pulverulent condition permits of a more intimate and thorough slaking of the
lime than would be possible by a complete initial slaking.
The mass on passage from the second mixing machine may be conveyed to a
reciprocating channel frame whence it may be distributed on the reciprocation
of the frame to the hoppers superposed above the presses employed. In the move-
ment of the reciprocating channel frame the mass is caused to pass along its entire
length and in passing a certain quantity drops through apertures suitably provided
in the frame above the hoppers. For convenience the reciprocating channel frame
is provided with a number of such apertures each of which is capable of being
closed, while each of the hoppers that are superposed above the presses employed
are divided into two compartments for convenience in alternate working. One
compartment in each of the series of hoppers employed is filled one day and allowed
to remain overnight for use in the presses and closed chambers on the following
day, the mass upon that day being caused to fill the other compartment of the
hoppers. The mass should be allowed to stand for a period of time of from 10 to 36
hours after the addition of the full quantity of water required for slaking before
being moulded the exact time being determined by the condition and appearance
of the mass.
The mass after treatment in the second mixing machine may probably be found
to be somewhat too stiff for moulding and a small quantity of water or of lime
milk must then be added in order to give it the necessary plasticity. Care must
be taken, however, to add no more water than is absolutely necessary for this pur-
pose as any excess will have to be eventually dried out entailing delay and expense
which is the special object of my invention to avoid.
The mass in its fresh condition is then moulded in presses of any usual con-
struction, and is immediately taken to the chambers without further drying and
and is there subjected to treatment by steam for preferably from 3 to 10 hours
and can there be completely indurated at preferably a pressure of from 6 to 8
atmospheres. The pressure of steam or duration of treatment may, however, be
increased for the purpose of effecting more rapid or greater induration. By treat-
ment in this manner the mass can stand a high pressure of steam to any degree
without disintegration.
It will of course be understood that no moulds are necessary to employ for con-
taining the mass when under treatment by steam.
The invention is not confined to the actual proportion of lime and sand herein-
before specified as it is possible to employ a greater or less proportion of lime as
required to produce different degrees of hardness.
To the mass on mixture in the second mixing machine may be added cement
slate dust or other ingredients as body materials.
Dated this 23rd day of Jan 1800
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.
An Improved Process for the Production of Building Stones, Bricks,
and like Articles,
I, HUGO WERTHIS, of 41, Aldersgate Street, in the City of London, Merchant,
(being a communication from abroad by Peter Kleber, formerly of 64, Trierer-
Allesstrasse, Malatatt-Burbach, Rhine Province, in the Kingdom of Prussia,

page_text: Manufacturer, and now of 9, Binger Strasse, Mayence, in the Grand Duchy of
Hesse, in the Kingdom of Prussia) 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:-
-
This invention relates to an improved process for the manufacture of building
stone and brick from a mixture of sand and time by which artificial stone or bricks
are more quickly produced of a better quality at a lower cost and by less costly
means than the processes hitherto employed in rendering mixtures of sand and
lime into artificial stone or bricks.
The objects of the improved process are to avoid the use of an excessive quan-
tity of water beyond the amount required for the complete hydration of the lime
used so as to render unnecessary the preliminary drying operation otherwise
requisite to economise fuel in the subsequent hardening process, to obtain a mix-
ture which can be conveniently handled in the process of moulding it by mechan-
ical pressure and which will set to some extent before it is finally hardened or
indurated by the action of high pressure steam and to wholly avoid the use of
the expensive and troublesome moulds frequently used in other such processes
within the steam chambers in which the induration or hardening is effected.
These objects are attained in the manner hereinafter described.
In carrying the invention into effect 1 part of ground burned lime is mixed
with from 8 to 15 parts by weight of moist sand the quantity of moisture present
in the sand preferably being that which it normally contains in its natural con-
dition. The lime and sand are uniformly incorporated with each other by being
intimately and thoroughly mixed within a mixing machine of any ordinary con-
struction. During the operation of mixing a portion of the lime is hydrated or
slaked accompanied by a considerable rise of temperature of the mass and thus
the whole of the moisture originally present in the sand combines with a portion
of the lime so that when the operation of mixing which should preferably be
continued until the whole of such moisture has combined with the lime is com-
pleted the resulting mixture is in a dry pulverulent form having a volume about
20 per cent. greater than its original volume. By this means a mixture of even
and uniform composition is obtained with the expenditure of a minimum amount
of power. The mixture is then discharged from the first mixing machine into
the inlet hopper of a second mixing machine. With some descriptions of lime it
is found to be advantageous to allow the mixture to remain at rest in the hopper
of the second mixing machine before treating it further with the object of ensur-
ing that the whole of the moisture originally present in the sand shall enter into
chemical combination with that portion of the lime which it is chemically equiva-
lent to hydrating.
The treatment in the second mixing machine consists in adding to the dry
pulverulent mixture by means of a sprinkler or other appropriate device for evenly
distributing water in jets or sprays such a further quantity of water and no more
as will suffice to slake or hydrate the remainder of the lime which was not slaked
or hydrated in the first stage of the process. The mixing is continued until the
whole of the water added is uniformly and evenly distributed throughout the mass.
A considerable rise in temperature due to the hydration of the further quantity
of lime results, and if the operation is properly conducted and an excess of water
beyond that chemically necessary for the hydration of the whole of the lime has
not been added the resulting mixture is of a dry and pulverulent form.
It is highly important that an excess of water should not be used at this stage
of the process otherwise a sloppy mass will be produced of uneven composition
and the bydration of the lime will not be so rapid as when an excess of water is
absent. Moreover the mixture is effected with a less expenditure of power than
would be requisite in the case of the plastic mass which would be the result of
adding an excess of water and a more thorough and intimate mixture and con-
sequently more complete hydration of the lime is obtained in a shorter time than
would otherwise be the case.

page_text: When the hydration of practically the whole of the lime has been effected a
small additional quantity of water or of milk of lime may be added in order to
temper the whole into a more or less plastic mass and render it into such a con-
dition that it will cohere with a considerable degree of firmness when submitted
to mechanical pressure in the moulds of the presses subsequently employed..
The quantity of water or of milk of lime necessary for this operation will depend
very considerably upon the state of fineness of division of the sand and lime em-
ployed and more or less upon the other physical characteristics of these materials.
The object however to be fulfilled is the production by means of a minimum
quantity of water of a more or less plastic mass which will firmly cohere when sub-
mitted to pressure in mechanical moulding presses and which will to a certain
extent set or harden after pressure and before it is hardened by the subsequent
process of steaming. Great care must however be exercised to add no more water
than is absolutely necessary for this purpose as any excess so added will have to be
eventually evaporated out of the mass in the steaming chambers and thus con-
siderable delay and increased expense by reason of the fuel thus wasted will be
entailed which it is one of the special objects of this invention to avoid.
The mass discharged from the second mixing machine is conveyed and dis-
tributed by means of a reciprocating channel frame to a series of hoppers super-
posed above the presses used for moulding the mixture into bricks or other
articles of the desired shape and size.
The accompanying drawing illustrates in diagrammatic longitudinal section
an arrangement of a reciprocating channel frame a superposed above the mould-
ing presses. The channel frame is supported by lateral pivotted arms b, and is
inclined in the direction in which the lime and sand mixture is distributed.
The reciprocation is effected from a counter shaft by means of a crank or crank
disc mounted thereupon and a connecting rod c.
The mixture of sand and lime may be delivered upon the reciprocating chan-
nel frame a by means of a conveyor which conveys the mixture from a lower
floor where the first mixing may take place.
In the movement of the reciprocating channel frame a the mixture is caused
by means of the reciprocation thereof to pass along its entire length and in so
doing a certain quantity of the mixture falls through apertures h¹ suitably
provided therein into the hoppers g h placed above each of the moulding presses i.
Each of the apertures g¹¹ mentioned is capable of being closed and each of the
hoppers which feed the presses into which the mixture is delivered is
divided into two compartments g and so as to provide for alternate working.
It is found to be an advantage in order to ensure thorough and complete
hydration of the whole of the lime to allow the mass to stand before moulding
it for a period of from 10 to 36 hours after it has been prepared in the manner
herein before described the exact time being determined by the condition_and
appearance of the mass. For this purpose each of the compartments in each of
the series of hoppers is filled one day and allowed to remain over night for use in
the presses on the following day the other compartment of the hopper being
used to receive the mass intended to be used on the next day following, the size
of the hoppers and the respective compartments being adjusted accordingly.
The mixture after standing as above described is then in its fresh condition
fed into the presses which may be of any usual construction and is therein
moulded by mechanical pressure into bricks or other articles of the desired
shape and size. The moulded bricks or other articles are then piled or stacked
upon trucks or carriages of convenient size and suitable construction and with-
out any preliminary drying process such as is used in other processes and the
loaded trucks are conveyed to and placed in steaming chambers of suitable size
and construction where they are subjected to the action of steam of a pressure
preferably of from 6 to 8 atmospheres for a period of from 3 to 10 hours according
to circumstances. By the action of the steam calcium silicates are formed in
the body of the moulded mass and as a consequence induration and hardening

page_text: of the bricks or other articles results. The pressure of the steam or the duration
of treatment may be varied or increased for the purpose of effecting more rapid
or a greater degree of induration.
By the preparation and treatment of the mixture in the manner hereinbefore
described bricks or other articles so prepared from it can be indurated at a higher
pressure of steam without undergoing disintegration. There is also the further
advantage that the moulds required to be used in other processes for holding the
mixtures of sand and lime during induration so as to avoid cracking or disin-
tegration are in this process quite unnecessary and thus the use and maintenance
of such moulds which are both costly and cumbersome and expensive to main-
tain and use are altogether avoided.
To the mixture produced in the second mixing machine may be added cement
slate dust or other substances of a like nature as body materials or substances
intended to impart any particular colour to the indicated articles.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I desire it to be understood that I am aware
that artificial stone or bricks have been made by the process of treating a mix-
ture of sand and lime with high pressure steam. I therefore make no claim to
the actual proportions of lime and sand hereinbefore specified or for such pro-
cess except when carried out under the particular conditions herein before set
forth but I declare that what I claim is:-
1. A process for the production of artificial stone or brick consisting in the
treatment of a mixture of sand and lime with water the water employed being
regulated as hereinbefore described and subsequently tempering, moulding and
hardening the material substantially as hereinbefore described.
2. A process for the production of artificial stone or brick consisting in the
treatment of a mixture of sand and lime with water and high pressure steam
according to the method herein before described in which the first step consists
in the production of a dry pulverulent mixture of sand lime and hydrate of lime
by employing sand in a moist condition so as to hydrate a portion only of the
lime employed; the second step consists in the production of a pulverulent mix-
ture of sand and hydrated lime by the employment of water in quantity only
chemically sufficient to hydrate the lime remaining unhydrated from the first
step and in allowing a sufficient time to complete the hydration of the lime; the
third step consists in bringing the mixture into a plastic cohesive condition
suitable for moulding by mechanical pressure by the addition if necessary of
a minimum quantity of water; the fourth step consists in moulding the desired
articles from the plastic mass prepared as described by means of mechanical
pressure and the fifth step consists in subjecting the moulded blocks to the action
of high pressure steam without the employment of moulds in the steaming cham-
ber all substantially as herein before described.
3. The hereinbefore described process for the production of artificial stone
and bricks.
This with day of N LANGI
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and
25, Cross Street, Manchester, Agents.