Improvements in the Process of Extracting and Drying Bones and the like.
Year: 1884

page_text: Improvements in the Process of Extracting and Drying Bones
and the like.
I, FRIEDRICH SELTSAM, manufacturer, of Forchheim, Bavaria, German Empire,
do hereby declare the nature of my said invention for "IMPROVEMENTS IN THE
PROCESS OF EXTRACTING AND DRYING BONES AND THE LIKE," to be as follows:-
Bones from which the grease has been extracted by the known methods by aid
of benzino, must always be subjected after extraction to a drying process in order
to remove all remaining water from them. It is moreover impossible even by
repeated washings with liquid benzine to extract all the grease from the bones,
because the water which remains after the grease has been extracted always
mechanically retains particles of fat, and prevents the benzine from thoroughly
penetrating the bones.
According to this present invention the drying and extracting process is
combined by introducing the solvent for the fat in the form of steam, and causing
the same to penetrate the material from which the fat is to be extracted with a
constant flow of the solvent until a complete evaporation of the water contained
in the same is effected, and consequently the bones are thoroughly dried. Any of
the ordinary apparatus employed in grease extracting can be made use of in the
present process, which is based upon the physical fact that all gases when heated
tend to absorb moisture up to the saturation point according to their temperature,
and, as is well known this power of absorption increases with the rise of tempera-
ture. So for example 1 cubic metre of air at 0 degrees centigrade is saturated by
absorption of 5 gr. of steam while at 85 degrees centigrade it is saturated by
absorption of 350 gr. of steam.
Instead of employing air especially heated for the purpose as is usually done in
the drying process which depends upon this principle, in the present method the
solvent for the fat is directly utilized by causing it to evaporate in the form of
vapour, and so in this manner penetrate the bones. If benzine vapour of about
80 degrees centigrade be used it will equally effect the removal of the water
from the bones, as when in the ordinary drying process, hot air of 80 degrees
centigrade is used.

page_text: The bones from which the greaso is to be extracted are placed in an extractor
provided with a perforated bottom which is connected by pipe having a stop cock
with a condenser.
A steam coil is fixed in the space underneath the perforated bottom, which serves
for heating and evaporating the liquid solvent introduced.
The solvent used may be any of the distillation products of petroleum naphtha
oil from shale, pit coal, or brown coal, preferably those which boil at a temperature
exceeding more or less the boiling point of water.
When the extractor is charged with the requisite quantity of solvent, the cock
of the conducting pipe is closed, and by blowing steam under pressure through the
coil the heating of the solvent placed in the lower compartment of the extractor
apparatus begins. The volatilized solvent thus formed rises upwards and condenses
partly on the lower layers of the bones placed, heating them and at the same time
dissolving the grease. This heat gradually increases until the bones attain the
temperature of the solvent vapour.
By this time the actual drying process and driving off of the water begins. The
vapour permeates freely through the bones and its tendency to absorb the watery
vapour up to the point proportional to its temperature effects the evaporation of
the water contained in the bones.
The benzine or other vapour used for extracting the grease which has in this
manner become saturated with the vapour of water escapes through a pipe to the
condenser where the steam of the water and vapour of the solvent enter and are
condensed and gathered in a receiver.
The specifically lighter solvent is conducted back through a pipe to the extracting
apparatus.
It is evident that the higher the temperature of the gaseous solvent, the quicker
and the more effective is the extraction of the water, and about 85 degrees centi-
grade is the lower limit of the boiling temperature of the solvent which may be
regarded as giving a satisfactory result. If a solvent be made use of which boils
at a lower temperature it is necessary to evaporate an excessive quantity of the
same as the limit of saturation is much lower. It is obvious that the quantity of
the solvent which has to be evaporated principally depends upon the boiling
temperature of the same.
With the present process there is, before the evaporation of the water begins,
firstly, the heating of the same up to the temperature of the solvent vapour,
provided same is below 100 centigrade, or up to that point if the temperature of
the solvent exceeds it.
By the continued supply of fresh dry solvent in the state of vapour, the
complete extraction of the water is effected. The heat necessary for the heating
of the water as well as for the evaporation of the same is drawn from the vapour
of the solvent, whereby a more rapid condensation of the latter, and at the same
time a more thorough extraction of the grease is procured.
In the methods hitherto adopted for the extraction of the grease, the conden-
sation is only slight because only the heat which is requisite for the heating of the
bones is made use of for the condensation of the steam. As this condensation did
not suffice for extructing the grease from the bones, it has been found necessary
hitherto to artificially assist the condensation by attempting to cool the extractor
by circulating water in or around the apparatus, or a partial condensation of the
solvent is obtained by quick evaporation by means of reduced pressure, or by
injecting cold benzine.
These aids can be entirely dispensed with in the new process, which becomes
thus much simpler. The operation above described is continued until all the water
is removed from the bones. As a rule the extraction of the grease is now complete,
and the solvent which still adheres to the bones is driven off according to the well
known method by aid of steam under pressure. As the bones and the solvent
adhering to them have attained an increased temperature only a slight condcusation

page_text: of the steam of the water is possible which is completely done away with, when
the solvent made use of has a boiling point of over 100 degrees centigrade.
Bones treated in this manner are completely dried after the removal of the
solvent, and can be conveyed direct to the crushing machine. They contain at the
most only traces of grease, while by the methods hitherto adopted for extracting
from 1 per cent to 24 per cent of fat generally remains, and further they do not
need any breaking up before hand, and can be removed to the extracting apparatus
in the same state as they were convoyed to the factory, because with the removal
of the water from the bones the extraction of the grease is considerably facilitated.
Besides, the bones become much more brittle by the complete removal of the
water and fat, and can therefore be broken up more easily.
As by the process above described the sulphur and nitrogen compounds present
in the bones are carried away and condensed with the grease extracted from the
bones, instead of remaining behind as with bones containing water, so on the
removal of the bones from the extraction apparatus, as well as by their further
treatment, the workmen and the neighbourhood of the factory experience no
annoyance.
The dried bones leave the extracting apparatus free from all smell. Lastly by
this new process an advantage is gained, for by the subsequent extraction of the
gelatine a more valuablo product is obtained, for the bones which are dried
according to the new process contain no grease, and the glue is thus not contami-
nated by fatty substances.
The new drying process thus procures a better yield of grease and glue, an
important simplification of the manufacture, besides considerable advantages from
a sanitary point of view. It is self-evident from the above described process that
other oleaginous substances can be treated in the manner described.
This process can also be worked at the ordinary as well as at higher or lower
pressure.

page_text: and the like.
I, FRIEDRICH SELTSAM, Manufacturer of Forchheim, Bavaria, German Empire,
do hereby declare the nature of my said invention for "IMPROVEMENTS IN THE
PROCESS OF EXTRACTING AND DRYING BONES AND THE LIKE" and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:-
Bones from which the grease has been extracted by the known methods by aid
of benzine, must always be subjected after extraction to a drying process in order
to remove all remaining water from them. It is morcover impossible even by
repeated washings with liquid benzine to extract all the, grease from the bones,
because the water which remains after the grease has been extracted always
mechanically retains particles of fat, and prevents the benzine from thoroughly
penetrating the bones.
According to this present invention, the drying and extracting process is
combined by introducing the solvent for the fat in the form of steam and causing
the same to penetrate the material from which the fat is to be extracted with a
constant flow of the solvent until a complete evaporation of the water contained in
the same is effected, and consequently the bones are thoroughly dried. Any of the
ordinary apparatus employed in grease extracting can be made uso of in the present
process, which is based upon the physical fact that all gases when heated tend to
absorb moisture up to the saturation point according to their temperature, and, as
is well known this power of absorption increases with the rise of temperature-So
for example 1 cubic metre of air at 0 degrees centigrade is saturated by absorption
of 5 gr. of steam, while at 85 degrees centigrade it is saturated by absorption of
350 gr. of steam.
Instead of employing air especially heated for the purpose as is usually done in
the drying process which depends upon this principle, in the present method the
solvent for the fat is directly utilised by causing it to evaporate in the form of
vapour, and so in this manner penetrate the bones. If benzine vapour of about
80 degrees centigrade be used it will equally effect the removal of the water from
the bones, as when in the ordinary drying process hot air of 80 degrees centigrade
is used.
The bones from which the grease is to bo extracted are placed in extractor A
provided with a perforated bottom a which is connected by pipe b having a stop
cock d with a condenser B.
A steam coil is fixed in the space underneath the perforated bottom a, which
serves for heating and evaporating the liquid solvent introduced through pipe g.
The solvent used may be any of the distillation products of petroleum, naphtha
oil from shale, pit coal, or brown coal, preferably those which boil at a temperaturo
exceeding more or less the boiling point of water
When the extractor is charged with the requisite quantity of solvent, the cock of
the conducting pipe g is closed, and by blowing steam under pressure through the

page_text: coilf the heating of the solvent placed in the lower compartment of the extractor
apparatus begins. The volatilized solvent thus formed rises upwards and condenses
partly on the lower layers of the bones placed in A, heating them and at the same
time dissolving the grease. This heat gradually increases until the bones attain
the temperature of the solvent vapour.
By this time the actual drying process and driving off of the water begins. The
vapour permeates freely through the bones and its tendency to absorb the watery
vapour up to the point proportional to its temperature effects the evaporation of
the water contained in the bones.
The benzine or other vapour used for extracting the grease which has in this
manner become saturated with the vapour of water escapes through pipe b to the
condenser B where the steam of the water and vapour of the solvent enter and are
condensed and gathered in receiver D.
The specifically lighter solvent is conducted back through pipe h to the extracting
apparatus.
It is evident that the higher the temperature of the gaseous solvent, the quicker
and the more effective is the extraction of the water, and about 85 degrees
centigrade is the lower limit of the boiling temperature of the solvent which may
be regarded as giving a satisfactory result. If a solvent be made use of which
boils at a lower temperature it is necessary to evaporate an excessive quantity of
the saine, as the limit of saturation is much lower-It is obvious that the quantity
of the solvent which has to be evaporated principally depends upon the boiling
temperature of the same.
With the present process there is, before the evaporation of the water begins,
firstly, the heating of the same up to the temperature of the solvent vapour,
provided same is below 100° centigrade, or up to that point if the temperature of
the solvent exceeds it.
By the continued supply of fresh dry solvent in the state of vapour, the complete
extraction of the water is effected. The heat necessary for the heating of the
water as well as for the evaporation of the same is drawn from the vapour of the
solvent, whereby a more rapid condensation of the latter, and at the same time a
more thorough extraction of the grease is procured.
In the methods hitherto adopted for the extraction of the grease, the con-
densation is only slight, because only the heat which is requisite for the heating of
the bones is inade use of for the condensation of the steam. As this condensation
did not suffice for extracting the grease from the bones, it has been found necessary
hitherto to artificially assist the condensation by attempting to cool the extractor
by circulating water in or around the apparatus, or a partial condensation of the
solvent is obtained by quick evaporation by means of reduced pressure, or by
injecting cold benzine.
These aids can be entirely dispensed with in the new process, which becomes
thus much simpler. The operation above described is continued until all the
water is removed from the bones. As a rule the extraction of the grease is now
complete, and the solvent which still adheres to the bones is driven off according
to the well known method by aid of steam under pressure. As the bones and the
solvent adhering to them have attained an increased temperature, only a slight
condensation of the steam of the water is possible, which is completely done away
with, when the solvent made use of has a boiling point of over 100 degrees
centigrade.
Bones treated in this manner are completely dried after the removal of the
solvent, and can be conveyed direct to the crushing machine. They contain at
the most only traces of grease, while by the methods hitherto adopted for
extracting, from 1 per cent to 2 per cent of fat generally remains, and further
they do not need any breaking up before hand, and can be removed to the
extracting apparatus in the same state as they were conveyed to the factory,
because with the removal of the water from the bones the extraction of the grease
s considerably facilitated.

page_text: Besides, the bones become much more brittle by the complete removal of the
water and fat, and can therefore be broken up more easily.
As by the process above described the sulphur and nitrogen compounds present
in the bones are carried away and condensed with the grease extracted from the
bones, instead of remaining behind as with bones containing water, so on the
removal of the bones from the extraction apparatus as well as by their further
treatment, the workmen and the neighbourhood of the factory experience no
annoyance.
The dried bones leave the extracting apparatus free from all smell. Lastly by
this new process an advantage is gained for by the subsequent extraction of the
gelatine a moro valuable product is obtained, for the bones which are dried
according to the new process contain no grease, and the glue is thus not
contaminated by fatty substances.
The new drying process thus procures a better yield of grease and glue, an
important simplification of the manufacture, besides considerable advantages from
a sanitory point of view. It is self evident from the above described process that
other oleaginous substances can be treated in the manner described.
This process can also be worked at the ordinary as well as at higher or lower
pressure.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
The improved process for the simultaneous extraction of grease from, and
dessication of bones and other substances containing fats, grease, or oil, by passing
a stream of amylic alcohol, benzine ligroine or other volatile hydrocarbon through
the bones, or other substances until the fat is extracted and the whole of the
moisture evaporated with the object of avoiding a supplemental drying substantially
as described.
WP. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, and
323, High Holborn, London,
Patent Agents for the Applicant.