Improvements in the Preservation of Alimentary and other Substances, and Apparatus therefor.
Year: 1893

page_text: Date of Application, 28th Jan., 1893
Complete Specification Left, 28th Oct., 1893-Accepted, 2nd Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Preservation of Alimentary and other
Substances, and Apparatus therefor.
I, CARL ADOLPH SAHLSTROM, of 14, Griffin Street, York Road, in the County
of London, Gentleman, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in the process and apparatus for the
preservation of alimentary and other substances forming the subject matter of
Letters Patent No. 3284 of 1887 and which mainly consists:-1stly in removing
all the germ-laden air in and around the material as far as possible by means of a
vacuum, and 2ndly in thoroughly saturating the tissues with a preservative solution
under the action of pressure.
In carrying out my invention I provide a receiver into which the substances 'to
be treated are placed and having a lid or cover adapted to be hermetically sealed.
In apparatus of small size the receiver is advantageously placed in an inclined
position and supported by means of struts over a tank for receiving the pre-
servative liquid, a pump being provided by means of which the liquid is drawn
from the tank and delivered into the receiver.
The advantage of this inclined receiver is that the sloping sides allow the gases
to escape without any hindrance.
In apparatus of large dimensions the cover of the receiver is advantageously
connected to a lever carried by a swing-arm or orane to facilitate the removal of
the said cover.
The apparatus which is advantageously used on shipboard, consists of a large
tank having around it a series of stays counocted to the walls of the tank by bolts
the said stays and bolts serving to prevent the tank from collapsing under the
external pressure during the time that the contents of the vessel are in vacuo. In
this modification also the cover covers an opening formed in one side of the vessel
and does not constitute one side thereof as is the case in the arrangements herein-
before described.
The fish or other substance to be treated is placed in a series of baskets of any
suitable shape which are then introduced into the receiver, the object of thus
employing a series of baskets being to provide passages to allow the escape of the
gases under the action of the vacuum, and the pressure to reach all parts of the
substance under treatment without having to force their way through a large body
of substance.
In the operation of the apparatus, a preserving fluid is forced or flows from a
cistern into the apparatus until the substances are covered, and then the air is
extracted by means of an ordinary air-pump or by other suitable means, this
extraction of the air being continued for half an hour or longer according to the
nature of the substance under treatment. An indicating tube is provided to shew
the escape of the gases. When sufficiently exhausted, the air pump is stopped and
the atmospheric pressure is admitted whereby the preserving liquid is driven into the
cavities previously filled with air or gases. The cook through which the air is
admitted is preferably provided with a very small hole (say of sufficient size to
receive a pin) to admit the air very slowly, as if the air was admitted suddenly the
effect would be to cause the sudden collapse of the tissues opened under the action
of the vacuum and so prevent the tissues from being properly impregnated with the
preservative liquid. After the atmospheric pressure is restored the air admission
cock is again closed and a pressure of from two to six atmospheres applied, in order
to make certain that the tissues are thoroughly saturated with the preservative.

page_text: This pressure is continued for from, say, a quarter of an hour to an hour, after
which the preservative liquid is allowed to pass back into the cistern and the
receiver having been opened the fish or other substance is removed and packed
either in common boxes or barrels with or without preserving solution.
If desired may subject the substances to be treated for two, three or more
times to the alternate action of vacuum and pressure.
The solutions which may be made use of in carrying out my invention naturally
vary according to the nature of the substance under treatment, for instance, in
treating say, fish which only require to be kept for a few days it is only necessary
to use a very weak solution of common salt, say a solution containing from
1 to 2 per cent., or pure common sea water may be used in this case. When, how-
ever, the fish are to be kept longer, it is necessary to add to the solution from
1 to 2 per cent. of boracic acid or common borax; also th to per cent. of
glycerine and both to Thath per cent. of essence of cloves.
When the fish are intended to be kept for several weeks they should be kept in
solutions containing from one to two per cent. of salt and from one to two and a
half per cent. of boracic acid.
By this method of preservation, the fish treated contain only a trace of the salt
and other ingredients of the preservative liquid while they retain almost unaltered
their original appearance and taste, and no special arrangements are required for
their conveyance to distant markets.
For pickling and salting fish, or pork, or other meat it is necessary to have a
stronger solution of salt, but in this case only a very small portion of boracic acid.
and glycorine are necessary.
For preserving eggs a smaller percentage of boracio acid and a larger percentage
of glycerine is to be used.
If fruits are to be preserved, no salt must be used, the preservative liquid being
composed as follows:-2 to 5 per cent. of sugar, to 2 per cent. of glycorino,
1 to 1 per cent. of boracic acid and roouth to ruth per cent. of essence of cloves.
For preserving meat, melted tallow, either alone or mixed with 1 to 21 per cent.
of boracic acid, can be used instead of a preserving liquid.
Dated the 28th day of January 1893.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Preservation of Alimentary and other
Substances, and Apparatus therefor.
I, CARL ADOLPH SAHLSTROM of 14, Griffin Street, York Road, in the County
of London, 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 to improvements in the process and apparatus for the
preservation of alimentary and other substances forming the subject matter of
Letters Patent No. 3284 of 1887.
It has been proved by experiment that the earliest stages of putrefaction in a
body or substance are associated with the presence of bacteria and other minute
organisms, and that in the case of fish and other animals putrefaction sets in
immediately after the disappearance of what is known as the "rigor mortis." It
has also been ascertained that the rate of the putrefactive process to a large extent
depends upon the quantity of gases and fluids present in the tissues. Hence it is
obvious that in order to preserve a substance it is necessary to treat the same whilst
in a perfectly fresh condition (which in the case of fish and other animal substances
is before the "rigor mortis" has passed off) so as to prevent bacteria or other
->

page_text: organisms from invading the substances or to render the muscles and other parts
incapable of providing the organisms with the nourishment necessary for their
growth and development.
To obtain these results it is necessary
1. To remove all the germ-laden air in and around the material as far as possible.
2. To thoroughly saturate the tissues with a preservative solution.
According to this invention the desired result is offected by subjecting the
substances to be preserved, whilst immersed in a preservative liquid, first of all to
a vacuum whereby the air and gases contained in the substances will be removed
and then to atmospheric or other pressure in order to force the preservative liquid
into the tissues.
Apparatus suitable for use in carrying out the invention is shewn in the accom-
panying drawings, in which :-
Figure 1 is an end elevation of a portable form of apparatus constructed according
to my invention; and
Figure 2 is a longitudinal section of the same.
Figure 3 is a sectional elevation of part of the apparatus illustrating structural
details.
Figure 4 shews a form of apparatus designed to be made of larger dimensions
than shewn in the preceding figures; and
Figure 5 is a sectional view drawn to an enlarged scale illustrating a detail of
construction.
Figure 6 is a vertical transverso section of a still larger form of apparatus;
and
Figure 7 is a plan of suob apparatus, the covor being removed.
Similar letters of reference indicate corresponding parts in the several figures.
a indicates the receiver into which the substances to be treated are placed,
and the lid or cover thereof, which lid or covor is provided with a groove con-
taining packing and adapted to fit the edge of the vessel und to be tightened against
the same by means of pivot-bolts c, c and nuts d, d thereon. e, e are slots formed
in the edges of the cover to allow the bolts to be engaged therewith without the
necessity for taking off the nuts each time that the cover is removed.
In the apparatus shewn in Figures 1, 2 and 3 the receiver a is represented as
being placed in an inclined position and supported by means of struts ƒ ƒ over a
tank g for receiving the preservative liquid. is a pump by means of which the
liquid is drawn from the tank g and delivered into the receiver a, and i is a cock
by means of which, after the treatment is completed, the liquid can be drawn off
into the tank.
This arrangement of inclined receiver is very suitable for apparatus of small
size, as the sloping sides of the vessel allow the gases to escape without any
hindrance.
j indicates a cock through which the gases contained in the vessel and in the
substance to be treated may be exhausted by means of any suitable apparatus
for producing a vacuum and through which the atmospheric or other pressure
may be allowed to enter the vessel in order to force the liquid into the
tissues of the substance; or a separate cock may be used for this latter purpose.
In the apparatus shewn in Figure 4 the receiver, which is of large
dimensions, is represented as arranged partly below a floor k and the cover is
connected to a lever I carried by a spring-arm or craue m to facilitate the removal
of the said cover which is first lifted by pulling down the lever and then removed
from over the top of the receiver by turning the crane m to the position indicated
by the dotted lines. Figure 5 shews an enlarged view of a portion of the cover
and of the vessel, the packing material between the vessel and the cover being
represented by the letter n.
The apparatus shewn in Figures 6 and 7, which is most advantageously used on
shipboard, consists of a large tank having around it a series of stays o, o connected
to the walls of the tank by bolts p, p the said stays and bolts serving to proyent

page_text: the tank from collapsing under the exteroal pressure during the time that the
contents of the vessel are in vacuo. In this modification also the cover only covers
an opening formed in one side of the vessel and does not constitute ono side thereof
ns in the arrangements heroiubefore described.
•
The method of using the apparatus heroinboforo described is as follows:-
The fish or other substance to be treated is placed in a series of baskota of any
suitable shape which aro then introduced into the receiver, the object of thus
employing a series of baskets being to provide passages to allow the escape of the
gases under the action of the vacuum and the pressure to reach all parts of the
substance under treatment without having to force their way through a large body
of substance. After the cover of the receiver has been fixed by the bolts c, the
-preserving fluid is forced or flows from a cistern into the apparatus until the
substances are covered, the tap at the top of the apparatus is then closed to
the atmosphere and the air is extracted by means of an ordinary air-pump or by
other suitable means, this extraction of the air being continued for half an hour or
longer according to the nature of the substance under treatment. An indicating
tube is provided to shew the escape of the gases. When sufficiently exhausted,
the air pump is stopped, and the atmospheric pressure is admitted whereby the
preserving liquid is driven into the cavities previously filled with air or gases.
The cock through which the air is admitted is preferably provided with a very
small hole (say of sufficient size to receive a pin) to admit the air very slowly, as
if the air was admitted suddenly the effect would be to cause the sudden collapse
of the tissues opened under the action of the vacuum and so prevent the tissues
from being properly impregnated with the preservative liquid. After the
atmospheric pressure is restored the air admission cock is again closed and a
pressure of from two to six atmospheres applied, in order to make certain that the
tissues are thoroughly saturated with the preservative. This pressure is continued
for from, say, a quarter of an hour to an hour, alter which the preservative liquid
is allowed to pass back into the cistern and the receiver having been opened, the
fish or other substance is removed and packed either in common boxes or barrels
with or without preserving solution.
If desired I may subject the substances to be treated for two, three or more
times to the alternate action of vacuum and pressure.
In treating fish where it is desirable to delay the disappearance of the "rigor
mortis" as long as possible, the central nervous system of the fish should be
destroyed as soon as they are taken from the water, they should also be gutted,
and kept at a low temperature.
The solutions which may be made use of in carrying out my invention naturally
vary according to the nature of the substance under treatment, for instance, in
treating, say, fish which only require to be kept for a few days, it is only necessary
to uso a very weak solution of common salt, say a solution containing from 1 to 21 per
cent., or pure common sea water may be used in this case. When, however, the
fish are to bo kept longer, it is necessary to add to the solution from 1 to 24 per
cent. of boracic acid or common borax; also th to per cent. of glycerine
and both to both per cent. of essence of cloves.
When the fish are intended to be kept for several weeks they should be kept in
solutions containing from one to two per cent. of salt and from one to two and a
half per cent. of boracio acid.
By this method of preservation, the fish treated contain only a trace of the salt
and other ingredients of the preservative liquid while they retain almost unaltered
their original appearance and taste, and no special arrangements are required for
their convevance to distant markets.
For pickling and salting fish, or pork, or other meat it is necessary to have a
stronger solution of salt, but in this case only a very small portion of boracic acid
and glycerine aro necessary.
For preserving eggs a smaller percentage of boracic acid and a larger percentage
of glycorine is to be used.

page_text: If fruits are to be preserved, no salt must be used, the preservative liquid being
composed as follows:-2 to 5 per rent. of sugar, to 2 per cent. of glycerino,
1 to 1 per cent. of boracic acid and rogoth to rooth per cent. of essence of cloves.
For preserving meat, melted tallow, oither alone or mixed with 1 to 21 per cent.
of boracic acid, can be used instead of a preserving liquid.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manuer the same is to be performed I declare that what I
claim is :-
―
1. The method of preserving alimentary and other substances consisting in
removing the gases existing in the tissues by mechanical means and substituting
therefor a preservative solution, substantially as described.
2. In proserving alimentary and other substances by the process referred to in
the preceding claiming clause introducing such substances into the apparatus_in
which they are treated in baskets, substantially as, and for the purpose, described.
3. The use in the process hereinbofore described of a solution containing salt or
of sea water for the purposo specified.
4. The use in the process hereinbefore described of a solution of salt and boracic
acid or borax to which may be added glycorine and essence of cloves, substantially
as, and for the purposes, described.
5. The use in the process hereinbefore described of a solution containing sugar,
glycerine and essence of cloves, substantially as described.
6. The use in the process hereinbefore described of melted fat or tallow either
alone or in combination with boracic acid, substantially as described.
7. The use in the process hereinbefore described of the various forms of
apparatus shown in Figures 1 to 3, Figures 4 and 5, and Figures 6 and 7 of the
accompanying drawings.
Dated the 28th day of October 1893.