A Method of Preserving Live Fish in Fixed Tanks or During Transport.
Year: 1893

page_text: Date of Application, 6th Mar., 1893
Complete Specification Left, 2nd Dec., 1893-Accepted, 6th Apr., 1894
PROVISIONAL SPECIFICATION.
A Method of Preserving Live Fish in Fixed Tanks or During
Transport.
1, GEORGE FREDERICK REDFERN, of the Firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of London,
Patent Agenta, do hereby declare the nature of this invention (a communication
from abroad by Carl Herrmann, of 16, Taubenstrasse, Berlin, în the Empire of
Germany) to be as follows:-
This invention relates to the preservation of live fish in fixed tanks or during
transport.
The forms of apparatus and methods at present in existence for effecting the
carriage and preservation of live fish without changing the water do not satisfy
the conditions necessary to the life of the fish to be preserved, since in these
forms of apparatus and methods the following facts are not taken account of :—
(1) The secretion and excretion of the products of tissue change given off by
the fish or the substances removed from them by mechanical action and remaining
in the tank in a dissolved or undissolved condition, which substances in their
decomposition continually develop carbonic acid and other compounds :-
•
(2) The removal of the carbonic acid given off by the fish in the process of
respiration.
From the neglect of these facts it has resulted that attempts have been made to
prolong the life of the fish by placing large quantities of water in the tank
destined to receive them.
In this way the fish may indeed be kept alive longer during the journey, but a
large quantity of water carried at the same time renders such conveyance of living
fish to market no longer profitable. Even by blowing nir into the water of the
tank, or by returning the same to the tank after filtration, by the methods hitherto
adopted it has not been found practicable to keep the fish alive for any length of
time, since,
(1) By the present methods of introducing air only a very small proportion
of oxygen is absorbed by the water, the bulk of it escaping in the form of
bubbles,
(2) The introduction of air, helps and hastens the decomposition of the organic
substances contained in the water of the tank, and thus augments the production of
carbonic acid;
(3) The organic substances dissolved in the water cannot be retained by even
the finest filter, and finally,
(4) The undissolved organic substances retained by the filter generate carbonic
acid by their decomposition, and the gas is taken up by the water as it returns to
the tank, and is conveyed to the fish which it is desired to preserve.
Now I have found that it is much more important to pay attention to the
removal of the carbonic acid given off by the fish in respiration and to the
elimination of that which is produced by the decomposition of the organic
substances excreted by the fish than to the introduction of oxygen into the water.
For the death of the fish is especially due to this carbonic acid which cannot bo
expelled from the water by the augmented introduction of air into the fish tanks.
In order then to effect the conveyance and preservation of living fish in the
smallest possible quantity of water it is requisite to continuously regenerate the
water in which the fish are to be kept or transported. i.e.-
(1) To render the organic substances given off or excreted by the fish innocuous

page_text: continuously, whether these substances be present in the water in a dissolved or
undissolved condition.
(2) To continuously remove the carbonic acid given off by the fish and supply
oxygen.
As has been previously mentioned the present method of supplying oxygen by
driving air into the water of the fish tanks is quite inadequate, because only a very
small portion of the oxygen so supplied is retained by the water. Moreover this
method does not effect the requisite removal of the carbonic acid and of the
substances which give rise to it from the water, on the contrary, the formation of
carbonic acid is thereby favoured.
According to the present invention live fish, crabs, lobsters, oysters, mussels and
the like are preserved in fixed tanks or during transport by the water which
contains the fish being first brought into contact with vegetable or animal charcoal
or other equivalent material which absorbs or retains the substances contained in
solution or in a solid condition in the water which is aftorwards atomized or
distributed in thin layers. An artificially produced current of air is at the same
time caused to traverse the finely divided water or to pass over the layers in which
it is distributed, and the water so treated is returned to the fish tank.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
A Method of Preserving Live Fish in Fixed Tanks or During
Transport.
1, GEORGE FREDERIOK REDFERN, of the Firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of London,
Patent Agents, do hereby declare the nature of this invention (a communication
from abroad by Carl Herrmann, of 16, Taubenstrasse, Berlin, in the Empire of
Germany) 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 the preservation of live fish in fixed tanks or during
transport.
The forms of apparatus and methods at present in existence for effecting the
carriage and preservation of live fish without changing the water do not satisfy tho
conditions necessary to the life of the fish to be preserved, since in these forms of
apparatus and methods the following facts are not taken account of :-
(1) The secretion and excretion of the products of tissue-change given off by the
fish or the substances removed from them by mechanical action and remaining
in the tank in a dissolved or undissolved condition, which substances in their
decomposition continually develop carbonic acid and other compounds :-
(2) The removal of the carbonic acid given off by the fish in the process of
respiration.
From the neglect of these facts it has resulted that attempts have been made to
prolong the life of the fish by placing large quantities of water in the tank destined
to receive them.
In this way the fish may indeed be kept alive longer during the journey, but a
large quantity of water carried at the same time reuders such conveyance of live
fish to market no longer profitable. Even by blowing air into the water of the
tank, or by returning the same to the tank after filtration, by the methods hitherto
adopted it has not been found practicable to keep the fish alive for any length of
time, since,
(1) By the present methods of introducing air only a very small proportion of
oxygen is absorbed by the water. the bulk of it escaping in the form of bubbles.

page_text: (2) The introduction of air helps and hastens the decomposition of the organic
substances contained in the water of the tank, and thus augments the production of
carbonic acid;
(3) The organic substances dissolved in the water cannot be retained by even the
finest filter, and finally,
(4) The undissolved organic substances retained by the filter generate carbonic
acid by their decomposition, and the gas is taken up by the water as it returns to
the tank, and is conveyed to the fish which it is desired to preserve.
Now I have found that it is much more important to pay attention to the removal
of the carbonic acid given off by the fish in respiration and to the elimination of
that which is produced by the decomposition of the organic substancos excreted by
the fish than to the introduction of oxygen into the water. For the death of the fish
is especially due to this carbonic acid which cannot be expelled from the water by
the augmented introduction of air into the fish tanks. In order then to effect the
conveyance and preservation of live fish in the smallest possible quantity of water
it is requisite to continnously regenerate the water in which the fish are to be kept
or transported. i.e.—
(1) To render the organic substances given off or excreted by the fish innocuous
continuously, whether these substances be present in the wator in a dissolved or
undissolved condition.
(2) To continuously remove the carbonic acid given off by the fish and supply
oxygen.
As has been previously mentioned the present method of supplying oxygen by
driving air into the water of the fish tanks is quite inadequate, because only a very
small portion of the oxygen so supplied is retained by the water. Moreover this
method does not effect the requisite removal of the carbonic acid and of the
substances which give rise to it from the water, on the contrary, the formation of
carbonic acid is thereby favoured.
According to the present invention I preserve live fish, crabs, lobsters, oysters,
mussels and the like in fixed tanks or during transport by continuously drawing off
the water which contains the fish and first freeing it of the compounds which give
rise to the formation of carbonic acid, whether they be dissolved or undissolved,
and by then either atomizing the water or reducing it to thin layers, and subjecting
it to the action of a strong air current, artificially produced, this current being with
advantage arranged upon the principle of the counter curront, the water being
finally returned to the tank.
In order to effect the removal, or reduction to an innocuous condition, of the
organic substances contained in the water in a dissolved or undissolved condition,
tho water is brought into intimate contact with bone or wood charcoal powder, or
other similar substance which possesses the property of taking up organio substances
held in solution by water, and of making the undissolved substances innocuous by
enclosing them.
The organic substances excreted by or given off from the fish being thus
captured, and retained in the special tank above mentioned by a filtering arrange-
ment, the carbonic acid contained in the water is removed from it by a continuous
process, oxygen being at the same time supplied to it. These objects may be
effected in various ways.
The water may be finely atomized by one of the usual arrangements suitable for
the purpose, and a strong current of air, artificially produced, be made use of for
the removal of the carbonic acid given off and for the introduction of oxygen
into the atomized water, the current of air being caused to pass through the finely
divided water, or, the water may be divided into thin layers and a strong current
of air may then be allowed to play upon the layers with advantage.
It is best to effect this in a closed chamber, from which the water, after being
regenerated and adapted to the needs of the fish to be transported or preserved, is
conveyed back.
It has yet to be mentioned that the water must at the same time be kept at a

page_text: degree of warmth corresponding to the time of year and the particular species
of fish, but for this purpose any warming or cooling apparatus preferred or
considered suitable may be employed. Whilst the rendering innocuous of the
· ·carbonic acid producing substances contained in the water is attained by the first
part of the process—namely by the introduction of materials which hold together
the organic substances the most important result namely the removal of the
carbonic acid given off as the product of the respiratory process of the fish, and the
introduction of oxygen to a very considerable extent into the separate particles of
water is effected by the reduction of the water to a fine state of division, either by
atomizing it or separating it into thin layers, a strong current of air being at the
same time allowed to act on it.
In the employment of this process, even when the quantity of water employed
does not exceed the weight of the fish contained in it, the fish when transported or
preserved remain perfectly fresh and are capable of being transported over longer
distances.
It is, as already stated, a matter of no moment in this new method what particular
arrangement may be employed for atomizing the water or distributing it in thin
layers, or for the production of the artificial current of air.
I have however in Figure 1 of the accompanying drawing shewn a vertical
section and in Figure 2 a horizontal section of a railway waggon provided with
an apparatus suitable for preserving live fish during transport according to my
invention.
In the railway waggon A are several fish-tanks some of which are represented as
portable barrels a, a, a nud another a¹ Figure 2 as an iron reservoir. These tanks
are provided with tightly closing covers from which pass branch pipes 6 connecting
the tanks with a common main pipe B. This main pipe B leads from the cleanser C
(which is in the form of an atomizer) and conveys the water therefrom freed from
carbonic acid and provided with fresh air back to the tanks. From the lower part
of the fish tanks a, a lead the branch pipes d connected with the main pipe D
Figure 2 which leads to the pump E. The pump E is actuated by the motor F, a
sucks in the impure water from the tanks a, a and then forces it through the filter
press Ginto the atomizing apparatus. Here the water purified by the filter press
is finely divided by a powerful current of air produced by a blower. The current
of air scizes the carbonic acid contained in the water and conducts it through the
small chimney whilst the water now perfectly cleansed and intimately mixed
with the oxygen of the air flows through the main pipe B and the branch pipes b
back to the tanks.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The herein described method of preserving live fish, crabs, lobsters, oysters,
mussels and the like, in fixed tanks or during transport consisting in continuously
drawing off the water which contains the fish and first bringing it into contact with
vegetable or animal charcoal or other equivalent material which absorbs or retains
the dissolved or undissolved substances in the water such water boing afterwards 4
atomized or distributed in thin layers, an artificially produced current of air being
at the same time caused to traverse the finely divided water or to pass over the
layers in which it is distributed, and the water so treated being returned to the fish
tank, substantially as set forth.
'CART JAQUÍDAST TO Can Usa na
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.