Concrete, and in the Apparatus Employed therein.
Year: 1886

page_text: Concrete, and in the Apparatus Employed therein.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman 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 firstly to the mixing of the materials employed in making
beton or concrete secondly to the arrangement or construction of apparatus for
mixing and triturating or reducing the said materials and thirdly to the operation of
ramming or laying the said materials in the moulds.
The concrete or artificial conglomerate known in France as "beton Coignet" is
prepared by mixing together sand, lime and cement slightly moistened with water
and triturating this mixture in cylindrical machines or mills. The pasty composition
thus obtained is delivered into moulds in which it is compressed by ramming performed
by hand or mechanically. In order that the blocks or structures formed with this
material may be of a homogeneous nature it is necessary to pay unremitting attention
to the proportions of sand, lime and cement passing through the mill. There is
comparatively little difficulty on this point in working small mills working inter-
mittently and dealing with small quantities only of materials at a time but it is
otherwise in the case of large mills working continuously. In order to obtain a better
result the materials are turned over on the ground with shovels before throwing them
into the mill. This method involves a considerable amount of labour and is moreover
an irregular and clumsy expedient and the mill has to do the work of mixing as well
as that of triturating or reducing the materials.
The effectual mixing of the materials is also impeded by the water that is sprinkled
over them when they are yet imperfectly mixed the lime and cement thus wetted
caking together in lumps which do not readily mix with the sand.

page_text: In laying and ramming the concrete in the moulds a certain amount of difficulty
is experienced in practice in effecting a perfect union between the parts that are laid
on different days. It is necessary to carefully clean and scrape the surface of the
concrete already laid and to wet it before proceeding to put on the next layer. These
preparations are liable to be frequently neglected or carelessly performed by the
workmen and the solidity of the structure is consequently endangered owing to the
imperfect union that takes place. All these disadvantages are obviated by means of
the improvements in the preparation and treatment of concrete forming the object
of this invention as hereinafter described.
The mixing of the materials is performed before they are wetted and in a specially
constructed apparatus a small quantity of materials being mixed at a time after which
the materials spread in a thin layer are sprinkled with water at the same time as they
are transferred to the hopper of a continuously acting reducing mill. Chloride of
calcium added to this mixture even when it consists simply of sand and lime has the
effect of accelerating and promoting the setting. Moreover chloride of calcium being
of a deliquescent nature retards the drying and thus enables the lime and cement to
harden gradually under the most favorable conditions. The chloride of calcium may
be used either in the form of a solution in the water which is thrown over the
mixture or preferably by mixing it with the lime just before the latter is mixed with
the other materials.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
An apparatus employed for effecting the mixture and trituration of the materials
according to this invention is illustrated in vertical and longitudinal_section in
Figure 1 of the accompanying drawings Figure 2 being a plan, and Figure 3 a
section taken along the line 1-2-3-4 figure 1.
This apparatus is carried on an iron frame G which may be provided with shafts
and mounted on travelling wheels as shown in the Drawing. The frame G carries a
footplate or platform P surrounded by a railing for the workman, a water cistern R
provided with a perforated tube and cock r, a mixer B and a measuring box or
hopper C cast in one piece and a shaking or vibrating table D. A ladder shaped
support or frame made in two parts is attached to the side of the hopper C and
carries a chain bucket elevator A. Underneath the frame G there is a triturating or
reducing mill F hung upon a shaft M supported by the side beams. All the operating
parts of this apparatus receive motion from a shaft Q drawn by a pulley N and a belt
connected with a portable engine or other suitable motor. This shaft drives the
mill F by means of bevel gear n n' and the mixer B by means of sprocket wheels ppl
figures 2 and 3 and an endless chain. The mixer transmits motion to the shaking
table D through wheels jj and also drives the elevator by means of chain wheels
The elevator shaft is provided with a clutch operated by a lever L³. I do not limit
myself to these methods of transmitting motion to the various parts as the same may
evidently be modified according to circumstances without affecting the principles of
the invention and an elevator of any suitable construction may be employed to carry
up the sand or gravel and deliver it into the measuring hopper C in place of the
elevator illustrated in the drawing.
99.
The measuring hopper C is made with sides inclined at an angle corresponding
with the natural slope of the sand in order to ensure its filling and is provided with
a door c in the form of à segment of a horizontal hollow cylinder capable of being
turned on an axis a by means of a hand lever L provided with a counterweight 7.
This arrangement enables the sand even when wet to be instantaneously discharged
from the measuring hopper. The sides of the mixer B are preferably cast in one
with those of the hopper C so that there may be no unevenness of surface liable to
obstruct the motion of the sand. A labourer standing on the platform P throws a
measured quantity of lime and cement into the mixer along with the sand and the
materials are effectually stirred and mixed by rotating arms carried on a horizontal

page_text: shaft B arranged in the mixer as indicated in the drawing (figs. 1 and 3). A dis-
charging door bin the form of a segment of a hollow cylinder capable of being turned
excentrically on a centre a¹ by means of a hand lever L'enables the contents of the
mixer to be discharged bodily and intermittently on to the shaking or vibrating
table D located underneath. The sides of the mixer are cast with or connected to
plates mm¹ for the purpose of enabling the apparatus to rest conveniently upon the
frame G. The shaking table D is suspended from the plates m m¹ by vibrating links 1.
An arm or arms d carried by the shaft e operated by a pawl or wiper acted on by a
ratchet or campushes against a transverse bar t attached to the table and carries
the latter to move towards the right hand side of the machine. Springs impel the
table in the opposite direction towards a transverse bar y when the cam releases the
wiper and thus impart to it a shock or jerk which throws off a portion of the mixture.
A slide or adjustable door enables the quantity thus intermittently discharged to be
regulated and causes it to be delivered in a thin layer whilst the perforated tube »
sprinkles water thereon which water may or may not contain chloride of lime in
solution and is supplied from the cistern R. In place of the table D an endless apron
may be employed having a continuous motion imparted to it and serving to convey
the materials from the mixer to the reducing mill. Such apron is employed in
combination with a regulator or slide spreading the materials in a thin layer and with
a perforated tube whereby the said materials are wetted as hereinbefore described.
v
The mixed and melted materials are delivered into the hopper of the reducing
mill F which is provided with rotating arms or stirrers in the form of portions or
segments (about of a circle) of a helix cast on bosses passed over square shafts as
illustrated in figure 3 and in the detail figure 4. Under these conditions the con-
struction of the helix or helices and the renewal of worn parts is facilitated. It is
evident that the construction and arrangement of the apparatus hereinbefore described
may be modified in various ways without affecting the spirit of the invention. For
example, when the mill F cannot be conveniently arranged underneath the mixer the
mixed and wetted materials may fall into a trough or trench whence they are
conveyed to the mill by a suitable elevator.
The mill F however constructed or arranged is enabled to be utilised throughout its
entire length for reducing the materials which have been previously mixed. The
manufactured beton which is delivered by the mill at X is discharged on to the
ground sliding down an inclined plane at the bottom of which it is received by or
shovelled into wheelbarrows and carried to the place where it is required.
If preferred the prepared beton may be delivered directly into trucks W from the
mill whose discharge orifice is sufficiently elevated to enable them to be conveniently
delivered in this manner.
At the same time as the mill F is treating the materials supplied thereto from the
table D, a fresh batch is being prepared in the mixer B.
It will be readily understood that the working of the elevator and of the mill are
continuous but that of the mixer is intermittent inasmuch as the mixer deals with
measured quantities or batches of materials at a time. The measuring hopper C thus
acts as an intermediary between a continuous movement and an intermittent move-
ment and the table D acts' in a similar manner between an intermittent movement and
a continuous movement. These two parts of the apparatus form a species of reserves
enabling the action of the apparatus considered as a whole to be regarded as continuous
or uninterrupted from the operation of taking up the sand by the elevator to that
delivering the prepared concrete or beton. The advantages of the arrangement
herein before described when compared with those heretofore employed are as
follows:-
1. A perfectly homogeneous and pure composition is imparted to all parts of the
structure. 2. The mill is enabled to produce a maximum of useful effect that is to
say is employed solely for reducing in place of having to do the work of mixing as
well as reducing as in the apparatus heretofore employed. The reducing action on
which the strength of the structure in great measure depends is thus augmented and
the strength of the structure is proportionately increased and; 3, a considerable

page_text: saving of labour is effected, two labourers only being sufficient to attend to the
apparatus one being employed on the platform P for introducing the required
quantities of lime and cement into the mixer and for working the levers L, LA, I
the other being stationed at the foot of the elevator in order to supply the latter with
sand and regulate the supply of water from the tube r.
In order to ensure a perfect union or continuity of the structure at the parts
where the operation of laying and ramming has been temporarily suspended or
interrupted blocks or pieces of wood T (figures 5 and 6) of trapezoidal form and
suitable thickness are employed being placed on the concrete when the mould is filled
to within a certain distance from the top. These pieces of wood being arranged at
intervals of say about three feet with their upper sides flush with the top of the
mould the remainder of the concrete is thrown down and rammed. When the blocks
(which if necessary are carefully arranged so that the thick ends alternate with the
thin ends) are removed along with the mould they leave recesses or hollows in the
upper surface of the concrete which presents a toothed appearance in elevation as
indicated in Figure 7. When the work is recommenced the fresh concrete is first
rammed into these recesses and afterwards over the entire surface. Two walls or
masses are thus produced which are effectually interlocked in a vertical direction and
their displacement in a horizontal direction relatively to one another is rendered
impossible owing to the taper or wedge shape imparted to the recesses by the
blocks T.
Having now particularly described and ascertained the nature of this Invention
and in what manner the same is to be performed I declare that what I claim is :-
First. Mixing the materials employed in the composition of beton or concrete in
a dry condition in a mixing apparatus or machine as hereinbefore set forth and
wetting them in thin layers before introducing them into the triturating or reducing
mill substantially as and for the purpose hereinbefore described.
Second. Mixing chloride of calcium with the materials employed in the composi-
tion of beton or concrete the said chloride being introduced either in the form of a
solution or in a dry condition substantially as and for the purpose hereinbefore
described.
Third. For preparing and treating beton or concrete as hereinbefore described
and claimed an apparatus comprising an elevator (A), a hopper or receptacle (C), a
mixer (B) a shaking or vibrating table (D) or its equivalent and a cistern (R) acting
in combination with a triturating or reducing mill (F) substantially as herein before
described with reference to figures 1. 2 and 3 of the accompanying drawings.
Fourth. The improved method of laying and ramming beton or
consisting in employing blocks (such as T) of trapezoidal form in such a manner as
to form recesses or hollows (figure 7) in the surface of the concrete in order to obtain
a perfect union between the layers substantially as herein before described with
reference to the accompanying drawings.
concrete