Improved Production of Moulding and Core Sand for Casting.
Year: 1895

page_text: Date of Application, 1st July, 1895-Accepted, 3rd Aug.,
1805
COMPLETE SPECIFICATION.
[Communicated from abroad by KARL PRINZLER, Foundry Foreman, and
BRIEGLER HANSEN & Co., Engineers, all of Gotha, in the German
Empire.]
Improved Production of Moulding and Core Sand for Casting.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, 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 :-
Moulding and core sand is at present prepared for casting by taking one or more
kinds of unused sand which is either burnt or mixed with sand which has already
been used for moulds, and after moistening with water again mixing the same
together. For wet casting coal dust is added, and, according to the nature of the
several kinds of sand, they are also either ground fine, or left in their original
condition. Every kind of sand is not suitable for moulding, and the necessary
kinds have often to be procured from considerable distances.
Even with moulds and cores made of sand prepared as above the disadvantage
cccurs that, on drying, cracks are produced, which require the mending and reblacking
of most moulds and cores. Also, adhering particles of sand which are often burnt
into the casting and which damage the turning tool, can generally only be removed
from the casting with great difficulty, so that the cleaning of the casting takes much
time and trouble. Lastly, in preparing the moulding sand, only a small proportion
of the sand already used can be again employed because this is rendered too poor
and fine through the heating, so that if a large proportion were used the mould
would not withstand the liquid iron, and would not allow of the escape of the gases
produced in casting.
It has been endeavoured to obviate these disadvantages by mixing with the sand
tar, asphalte, or similar bodies.
No doubt the sand prepared with this admixture was more plastic than ordinary
sand, and the moulds and cores were hard and porous after the drying, but the
employment of such sand was subject to other considerable defects which rendered
its general use impossible.
Thus moulds and cores prepared with tar sand cannot be repaired, if parts
thereof are broken off or damaged as the tar sand does not take up water and can
consequently not combine with repairing sand.
Again, on using tar sand for moulds and cores there are produced in casting
such unpleasant vapours, that the workmen in the foundry cannot endure thein
for long.
Furthermore the effectual admixture of a large quantity of sand with tar is
subject to great difficulties and large storing space and a storage of several days is
required until the sand treated with a tar solution becomes uniformly impregnated
with the liquid.
Lastly, the preparation of the tar sand is very unpleasant, as the workmen can
only remove with difficulty the dirt from this sand which adheres to their clothes,
linen, hands and face.
On all these grounds the use of tar sand, which at one time was much talked of,
has been gradually given up.
The present invention has for its object the use for admixture with moulding

page_text: sand, of a more or less thin watery paste formed the rape seed or linseed cake or
the like resulting from oil manufacture.
By means of this admixture with the moulding sand all the advantages that were
sought to be attained by the tar sand are gained and at the same time all the
defects are avoided that are attended on such use.
By the admixture of a watery paste of rape or linseed cake and the like with the
moulding sand, a plastic, easily worked sand is obtained, which can be mended like
any other sand and which, in casting produces absolutely no unpleasant gases.
The moulds and cores made of moulding sand with addition of rape or linseed cake
and the like are not liable to disintegrate at the surface during the casting that is
to say no particles of sand become detached at the surface. The surfaces of
moulds and cores prepared of such sand are exceedingly clean and smooth, and the
moulds are exceedingly porous so that the gases evolved in casting can pass away
freely withent causing the surfaces of the casting to become uneven, honeycombed
or porous. On the contrary, the castings produced in moulds made of sand with
rape or linseed cake or the like, shew a surface much smoother and freer from air
bubbles or pores, and a fine uniform colour, which last named fact shews that the
admixture of the rape or linseed cake and the like with the moulding sand exercises
a very beneficial action on the casting.
Furthermore, the dried cores prepared from this sand are exceedingly friable
after casting so that they can be removed from the castings with the greater
facility, and generally, the cleansing of the castings from the improved sand can he
effected better than with the tar sand, and with considerably greater facility than
with ordinary moulding sand at the same time, the moulding sand mixed with rape
or linseed cake or the like is equally applicable with advantage for moulds and
cores whether for dry or for wet casting.
The admixture of rape or linseed cake or the like with moulding sand is also of
the greatest importance from, the fact that not only the poorest sand, in fact sand
of any description, can be used as effectually as the most suitable descriptions of
sand: for moulding, purposes, but also the completely burnt sand which heretofore had
to be removed from the foundry, because it was of no farther use, can be used over
and over again, with or without addition of a very small quantity of new saud of
interior quality.
By this means not only are great savings in costs effected which are caused in
many foundries.on account of having to obtain a suitable moulding sand frequently
from great distances but also in many foundries the considerable custs caused by
having to convey away the useless and burnt sand are mostly saved.
It is only necessary to provide new sand to make good for unavoidable waste,
and in addition to provide for a very small quantity for regenerating the used
moulding sand; but for this the poorest sand can be used as this cau, when mixed
with the rape or linseed cake or the like, be worked as well as the best and most
cobering moulding sand that has theretofore been used.
For preparing the sand with the admixture of the rape or linseed cake and the
like, the following modes of proceeding is employed.
The rape or linseed cake or the like, is reduced to small fragments, and the meal
thus produced is mixed with cold or preferably warm water in suitable receptacles,
to form a thin paste. This mixture is left for a suitable time in the vessels
with frequent or continuous stirring, and is then poured over the sand spread in a
suitably thick layer on the floor, such sand having previously been mixed in the
ordinary manner and moistened with water.
After the liquid paste has saturated the sand, this is shovelled up and then
treated in the known manner.
The preparation of the moulding sand can also be effected in the following
manner, which is however not so advantageous.
The moulding sand is mixed in the old manner, the ground rape or linseed cake
or the like is then added, and incorporated therewith, and the whole is then
moistened with water and farther treated in the known manuer.

page_text: In conclusion it is to be observed that it is also of advantage to mix ground coal
with the sand mixture, before the addition of the rape or linseed cake or the like,
(whether this be added as a paste or dry) if the moulding sand is to be used for so
called wet casting.
If the spaces available allow of it, it is of advantage to prepare the sand in
larger quantities and to allow it to lie for some days, and when using it, to remove
the oldest sand from below, while fresh quantities of sand mixed with the rape or
linseed cake or the like are always added at the top.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is:-
1. The production of moulding and core sand by mixing ordinary or burnt sand
or a mixture of both, with a watery paste of rape or linseed cake or the like.
2. The production of core and moulding sand by mixing the sand referred to in
Claim No. 1 with ground rape or linseed cake or the like, and then moistening
with water.
ABEL & IMRAY,
Agents for the Applicant.