IMPROVEMENTS IN FREEZING MACHINES
Year: 1885

page_text: We OTTO KOCH, Merchant and RUDOLPH HABERMANN Civil Engineer both of
Berlin in the German Empire do hereby declare the nature of said invention
for "IMPROVEMENTS IN FREEZING MACHINES" to be as follows:-
This invention relates to improvements in absorption freezing or refrigerating
machines, by which term are meant such machines as those in which for the purpose
of refrigeration the method of causing bodies to pass over from the liquid into the
gaseous state is wholly or in part superseded by the dissolution of such bodies in
another suitable body out of the ice producer (evaporating refrigerator) for example,
ammoniacal gas in nonsaturated aqueous solution of ammonia (salmiakgeistlösung);
ammoniacal gas in glycerine; methylamine in an nonsaturated mixture of methyl-
amine and water, and other similar compounds.
The result obtained from such machines (absorption machines) in practical
working has been the production of about ten kilos of ice by the expenditure of
one kilo of coal. By means of the refrigerating or freezing machine which forms
the subject of this invention the main object of greater working economy is
attained, nearly eighteen kilos of ice being produced by the expenditure of one kilo
of coal: The invention is here described with reference to an ammonia-absorption
freezing machine. It consists substantially of an ammonia boiler of an ice former,
of a pump and of a condenser. The chief function of this freezing machine is the
evaporation continuously within the ice former of a liquid for the purpose of
destroying or extracting heat. The other functions have for object to transfer the
gas generated in the process back again into the liquid form and so render it
suitable for fresh use for freezing purposes. Aqueous solution of ammonia saturated
or nearly saturated with ammonia is supplied to the boiler and heated, whereupon
it gives off a portion of its ammonia in the form of gas. This ammonia collects in
a part of the boiler and condenser which is not occupied by the aqueous solution of
ammonia. Its pressure gradually increases as both vessels are hermetically closed,
and ammoniacal gas driven out of the aqueous solution of ammonia continues to
enter the limited space. In the condenser the ammoniacal gas is cooled down
and becomes liquid at a pressure which is governed by the degree of coolness or
refrigeration.
Such liquid is conducted into the ice former (evaporator) and is there evaporated
under a suitable pressure. In order to remove the gas evolved in the ice former it
is conducted into a vessel termed the absorption vessel supplied with an aqueous

page_text: solution of ammonia that is not saturated, and is dissolved and absorbed. The heat
thereby generated is removed by cooling-water in a suitable manner.
The aqueous
solution of ammonia now saturated by reason of the absorption of ammoniacal gas
is pumped back again into the boiler. The aqueous solution of ammonia in the
boiler which has been made poorer in ammonia by reason of the evolution of
ammoniacal gas by means of heat is withdrawn from the boiler through a discharge
pipe, passed through a cooling worm to be cooled and then conducted to the
absorption vessel where as before described it becomes saturated with the gas from
the ice former. The heat applied to the boiler is utilised on the one hand to
evaporate or vaporise the ammonia contained in the aqueous solution of ammonia
into the liquid form, and on the other hand to bring to the boiling point the
saturated aqueous solution of ammonia pumped into the boiler from the absorption
vessel,
When the aqueous solution of ammonia has been heated in the boiler to such an
extent that all the ammonia shall have passed away from the same, then the liquid
passing into the absorption vessel will be not be weak aqueous solution of ammonia
but water. If the water is again saturated with ammonia one hundred parts by
weight will consist of 68 parts of water and 32 parts of ammonia. In order to
dissolve in the absorbing vessel a certain quantity by weight of ammonia,-
according to this invention a much smaller quantity of weak aqueous solution of
ammonia suffices and consequently a less quantity of saturated aqueous solution
of ammonia has to be pumped back into the boiler thus allowing of a great saving
of fuel in the heating of the same up to the temperature of the aqueous solution of
ammonia in the boiler. In order that the aqueous solution of ammonia destined
for the absorption of the ammonia in the in the absorbing vessel may only contain
the smallest practicable quantity of ammonia the boiler is divided into a number of
separate chambers. The aqueous solution of ammonia pumped therein passes into
a first chamber at one end of the boiler to the aqueous solution of ammonia there
present flows out of this one when it is full to a second chamber and so on to the
other chambers from the last of which it passes to the absorption vessel. The last
chamber of the boiler receives the greatest heat which may be from steam or from
a direct fire, and the next following chambers a lesser heat corresponding to their
distance from the last chamber. The aqueous solution of ammonia in the first
chamber is saturated with ammonia and merely requires to receive a small addition
of temperature for the purpose of expelling ammonia. In the first as in each
successive chamber gas is evolved; the object in view being that the aqueous
solution of ammonia passing to the absorption vessel shall be as poor as possible in
ammonia so that upon the return passage a correspondingly small quantity of
saturated aqueous solution of ammonia has to be brought to the temperature
of the aqueous solution of ammonia in the boiler thus economising heat. This
object may also be attained by the concentration of the aqueous solution of
ammonia to a higher degree in the absorption vessel and thereby allowing of the
supply thereto of a larger quantity of ammonia than has hitherto been the case.

page_text: We OTTO KOCH, Merchant and RUDOLPH HABERMANN, Civil Engineer, both of
Berlin in the German Empire do hereby declare the nature of said invention for
"IMPROVEMENTS IN FREEZING MACHINES, 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 absorption freezing or refrigerating
machines, by which term are meant such machines as those in which for the
purpose of refrigeration liquid bodies passed over from the liquid into the gaseous
state are either wholly or in part conducted from the ice former or vaporiser into
another suitable body, for example, ammoniacal gas into non-saturated aqueous
solution of ammonia (salmiakgeistlösung); ammoniacal gas into glycerine;
methylamine into a non-saturated mixture of methylamine and water, etcetera.
The object of our invention is by means of these improvements so to conduct
the process of ice making as to effect a great saving of fuel and expense, for
instance in the case of refrigerating machines of the ordinary kind, ten kilo-
grammes of ice are produced by the expenditure of one kilogramme of coal. By
means of the refrigerating or freezing machine which forms the subject of this
invention eighteen kilogrammes of ice may be produced by the expenditure of a
similar quantity of coal.
A freezing machine in accordance with our invention consists substantially of an
ammonia boiler giving off ammonia; a condenser; an ice former; an absorption
vessel and a pump. The chief function of the machine is the continuous evaporation
within the ice former, of a liquid, for the purpose of dissipating heat. The other
functions have for object to transform the gas evolved in the ice former back again
into the liquid state.
Aqueous solution of ammonia saturated or nearly saturated with ammonia is
supplied to the ammonia boiler and heated, whereupon a portion of the ammonia
passes over into the gaseous state, and collects in the condenser where it is cooled
down and thus transformed into a liquid which is conducted into the ice former.
In order to remove the gas evolved in the ice former it is conducted into the
absorption vessel, which contains non-saturated aqueous solution of ammonia, and
thus the gas becomes there absorbed in the said solution. The heat thereby
generated is dissipated by means of a cooling worm.
The saturated aqueous
solution of ammonia is passed back again into the ammonia boiler and the process
goes on over again.
The aqueous solution of ammonia employed for the absorption-in the absorption
vessel of the ammoniacal gas, is obtained from the ammonia boiler in which the
ammoniacal gas had by the application of heat been driven out of the aqueous
solution of ammonia. This aqueous solution of ammonia is cooled down by
passing it through a cooling worm. According to the usual practice when the
aqueous solution of ammonia supplied to the machine contained 32 parts by weight
of ammonia in 100 parts by weight of the solution, the solution poor in ammonia
entered the absorption vessel in the proportion of about 25 parts by weight of
ammonia to 100 parts by weight of the aqueous solution of ammonia and there

page_text: became saturated to the former extent. The aqueous solution of ammonia thus
took up about one fourteenth of its weight of ammonia and in this state was
pumped back into the ammonia boiler, therefore thirteen fourteenths of the aqueous
solution of ammonia carried one fourteenth of ammoniacal gas. The heat applied
to the ammonia boiler on the one hand evaporates the ammonia contained in the
aqueous solution of ammonia, and on the other hand brings to the boiling point
the aqueous solution of ammonia pumped into the ammonia boiler from the
absorption vessel. Hitherto when the heat required for expelling a given quantity
of ammonia from the aqueous solution of ammonia was say 266 units, it was
necessary to employ 277 units for heating the aqueous solution of ammonia pumped
into the boiler. If required the aqueous solution of ammonia may be heated in
the boiler to such an extent as shall expel all the ammonia therefrom, in which
case the liquid conducted from the ammonia boiler into the absorption vessel would
be water only. When this water becomes saturated again by taking up ammonia,
one hundred parts by weight consist of 68 parts of water to 32 parts of ammonia,
thus in this case two thirds water are the carriers of one third ammonia
approximately. Therefore when very weak aqueous solution of ammonia (or water)
is supplied to the absorption vessel a comparatively smaller quantity thereof
suffices, consequently a smaller quantity has to be pumped into the ammonia boiler,
when a correspondingly smaller quantity of heat has to be expended in heating
the same.
Now in order that the aqueous solution of ammonia destined for the absorption
of the ammoniacal gas in the absorption vessel may only contain a small quantity
of ammonia, we construct the ammonia boiler in the manner shewn in the
accompanying drawing at Fig 1 that is to say in several chambers open at top.
Heat may be applied thereto by means of a fire or by means of steam.
The aqueous solution of ammonia is pumped into the ammonia boiler at B when
it first enters the chamber a and mixes with the aqueous solution of ammonia there
present. The contents of the first chamber a overflow into the second chamber a¹
and so on to the others and last of the chambers, where, after giving off ammonia
it is again conducted to the absorption vessel through the outlet C. The ammonia
boiler is shewn provided with a steam heating worm.
The heating operation takes place in the following manner :-
The last chamber as of the several chambers receives the greatest heat and the
first chamber a the least heat. The aqueous solution of ammonia in the first
chamber a contains the most ammonia and therefore requires little addition to its
temperature in order to expel ammonia. Inversely it is necessary to apply a
greater heat to the chamber a³ in order to expel ammoniacal gas therefrom, by
reason of its contents having gradually become poor in ammonia. The object in
view is to have the solution as poor as practicable in ammonia, so that only a
comparatively small quantity of the aqueous solution of ammonia is required in
the absorption vessel. For instance when the aqueous solution of ammonia is
very poor in ammonia, a small quantity of the same may absorb a comparatively
large quantity of the ammoniacal gases within the absorption vessel; therefore
when the aqueous solution of ammonia is conducted from the absorption vessel
back again to the ammonia boiler a lesser quantity of the same has to be heated
up to the temperature of the solution in the said boiler. This object may also be
attained by the concentration of the aqueous solution of ammonia to a higher
degree in the absorption vessel thereby allowing of the supply thereto of a larger
quantity of ammonia than has hitherto been the case.
Fig 2 of the accompanying drawing shews the absorption vessel constructed for
the aforesaid purpose. The ammoniacal gas coming from the ice former enters
at M. At N the aqueous solution of ammonia poor in ammonia enters the vessel
passing into the chamber b and successively into the other chambers open at top, b¹,
b², b³, bª, 6º, 6º finally leaving the vessel at the outlet L. T is the inlet for the
cooling water and 8 the outlet for the same. The ammoniacal gas entering at M
fills the vessel, the weak solution which enters the chamber b through the inlet Ņ

page_text: requiring at this point the least cooling power for the absorption of the ammoniacal
gas. Inversely the chamber 6 has taken up a comparatively large quantity of
ammonia and therefore requires greater cooling power to render it capable of
taking up an additional quantity of ammoniacal gas. The greater cooling
temperature is obtained in the chamber 66 and proportionately and gradually less
in the other chambers, by reason of the fresh cooling water being caused to enter
the vessel at T, namely, at the end of the absorption vessel where the solution
contains the largest quantity of, or is most saturated with ammonia.
The absorption vessel instead of being of horizontal construction as shewn in
Figs 2 and 2 may be of vertical construction as shewn in Figs 3, 4, 5 and 6, in
which case the absorbing liquid passes out of the pipes m, m, m, and on to the
cooling tubes n beneath until it reaches the bottom of the vessel and is discharged
through the outlet c. The ammoniacal gas enters through the pipe d passing
through the perforated plate e in an equally distributed volume, it then rises
impinging against the series of tubes. In order to prevent a too quick descent of
the absorbing liquid it is advisable to fix wires between the tubes so that instead
of falling suddenly it may run down on the wire work and tubes. This method
of construction allows of the surfaces of contact for the gas presented by the
absorbing liquid being extremely large. Figs 4, 5 and 6 shew different arrange-
ments of the cooling tubes in plan.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
1. The construction and arrangement of freezing machines of the kind referred
to in such manner that the freezing process may be so conducted that the
absorbing liquid in being prepared for repeated use as an absorbing medium shall
where it contains the largest proportion of the freezing body, come in contact with
heating surfaces of a lower temperature, than where it contains the smallest
or a smaller proportion of the freezing body or medium, and in such manner that
the said absorbing liquid shall be of varying temperatures and degrees of
concentration at different parts of its bulk substantially as hereinbefore described
and illustrated in the accompanying drawing with reference to Figs 1 and 1.
2. The construction and arrangement of freezing machines of the kind referred
to in such manner that the gas, the absorbing liquid and the cooling water are
supplied to the absorption vessel so that the gas enters the same at the place where
the absorbing liquid is the more highly concentrated and is cooled by the cooling
water of the coldest temperature whilst where the absorbing liquid is less or the
least concentrated, and of greater capability of absorption, it is cooled by the
cooling water that has gradually increased in temperature, substantially as herein-
before described and illustrated in the accompanying drawing with reference to
Figs 2, 2, 3, 4, 5 and 6.
3. The apparatus represented in the accompanying drawing for the purposes
specified substantially as described and illustrated."