Improved Refrigerating Liquid.
Year: 1894

page_text: Date of Application, 7th July, 1894-Accepted, 6th Oct., 1894.
COMPLETE SPECIFICATION.
Improved Refrigerating Liquid.
I, MARTIN WANNER, a citizen of the United States, resident of Yorktown in
the County of Delaware and State of Indiana, a Chemist, 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:-
My invention relates to a new and improved-refrigerating liquid.
The object of this invention is to prevent or retard the thickening or congelation
of the volatile liquid employed in evaporating refrigerating plants, and ice machines,
and to regulate the rapidity of evaporation of the volatile liquid used.".
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J
The main difficulty encountered in producing cold by the evaporation of volatile
liquids of the classes herein contemplated is their tendency to congelation and their
consequent impaired mobility and conductivity. For instance—the rapid evapora-
tion of carbon bi-sulphide (CS2) causes such a reduction of temperature that the
conductivity of the ordinarily employed vehicles or conductors, whose office it is to
convey the caloric from the objects to be cooled to the evaporating liquid, is
entirely inadequate to perform the work rapidly enough to keep the liquid in a
fluid condition, because the evaporation, being induced by and proceeding from
mechanical means, irrespective of the conducting or conveying capacity of the
medium employed, abstracts caloric from the liquid and it congeals. Just as soon
as this occurs, the contact between the objects to be cooled and the evaporating
liquid becomes imperfect, and the effectiveness of the apparatus is destroyed or at
least impaired. To illustrate: Assuming the apparatus to be used for the manu-
facture of artificial ice, one of two methods may be employed; either the
evaporating liquid is in direct contact with the vessel holding the water to be
frozen, or the evaporation is carried on in pipes or other vessels which are in
contact or communication with the vessels of water to be frozen by means of a
conducting or conveying medium, preferably fluid or liquid. In either case, the
successful working of the apparatus depends upon the intimate contact of the
evaporating liquid or its vapors with the sides and bottom of the vessels holding
the water to be frozen, or with the partitions or walls enclosing the evaporating
liquid, or its vapors, as would be the case if the evaporation was carried on in pipes
or other vessels. During the process, the volatile liquid having by too rapid
evaporation become solid, loses its mobility; and consequently its conductivity, and
is unable to closely envelop or touch the vessel holding the water to be frozen, or
the conducting medium, as the case may be, and moreover, evaporation practically
ceases until the temperature of the frozen mass is augmented, and it begins to
melt. The conductivity, or better, the carrying capacity of heat of liquids
dépends upon their mobility and consequent close contact with the objects subjected
to their action, therefore, a stiffened or solid mass is incapable of doing the work
properly.
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That the conductivity of a liquid depends upon its mobility will be apparent
from the following:
97
It is one of the fundamental laws of physics, that variations in temperatures of
liquids always caused currents in such liquids, and the greater the variation in
temperature, the more rapid must be the involved currents, and the volatility of
liquids is relative; they are all volatile at certain temperatures, and the same law
governs them all. Anything, therefore, which impairs the free circulation of the
currents in the liquid above referred to, as for instance, thickening by the

page_text: congelation of the liquid, of course, impairs its volatility and consequent con-
ductivity. In other words, anything which retards the mobility of the liquid also
retards its volatility. Furthermore, to illustrate that which is above stated
relative to the solid or partially congealed liquid being unable to closely envelop
or touch the vessels holding the water to be frozen, or the conducting medium, as.
the case may be-Assume a can filled with melted lard. As the lard cools and
becomes solid, it is a well-known fact that the congealed contents of the can shrink
away from it, leaving an annular space all about the cake of lard within it.
Therefore there is no close contact between the lard and the sides of the vessel.
Consequently the heat conveying capacity of the lard relative to the can is
seriously impaired when the lard is congealed. This is precisely the action of the
volatile liquids ordinarily employed for refrigerating purposes, because that which
occurs in the case of lard, occurs in the case of all non-crystallizing liquids, and
these are the ones now under consideration. It is only the liquids that crystallize
while congealing that occupy a larger space when solid, than they do in liquid
state. All others shrink.
It is desirable to obtain as rapid action as possible in refrigerating plants,
especially those adapted to the manufacture of ice, in order that the temperature
produced may be as low as possible. The difference in temperature between the
evaporating vessel and that of the tank or vessel containing the conveying medium
determines the rapidity of the circulation of said medium and consequent velocity
of the transference of caloric, hence any means that makes it possible to lower
the congealing point of the volatile liquid used adds to the effectiveness of the
apparatus.
Now, therefore, to prevent the thickening or congelation of the volatile liquid,
I mix it with oils or other liquids or fluids of as nearly as may be the same specific
gravity as itself, being perfectly miscible therewith. (If water is used directly as
a condensing medium, or as a seal against atmospheric contact, it is of course
necessary that the mixed liquids should be insoluble in water.)
The liquids which I employ for the purpose of preventing congelation and for
regulating the rapidity of evaporation may be volatile or non-volatile, all that is
essential is that the same should have the property to so intimately mix, (without,
however, combining chemically) as to prevent the crystallization the one of the
other, and to secure this result, it is preferred to use liquids having different
temperatures of congelation, but as near as may be equal specific gravity, and of
the greatest possible mobility in order to promote the best possible contact with the
objects to be cooled.
To effect, however, the regulation of the rapidity of evaporation only, of the
volatile liquid, without regard to the lowering of the congealing point, the liquid
60 employed should be one of lower degree of mobility; in all cases, however, it
is essential that the liquids used should be perfectly miscible with the volatile
liquid.
To more particularly explain the use of the mixture of liquids or fluids in
operating an ice making plant, I will now proceed to describe the mode of
procedure, the object of the mixture being to retard the congelation of the
evaporating liquid, in this case carbou bi-sulphide (CS,). To this end chloroform
is added to the carbon bi-sulphide to the proportion of 9 parts of the sulphide
to of chloroform (CHC),) and the mixture so obtained is exposed in evaporating
vessels to a vacuum more or less per ect, or to a rapid current of air. The vapors
are condensed in suitable condensing apparatus, re-conveyed to the evaporating
vessels and again subjected to the vacuum. To regulate the rapidity of evaporation
or to retard the same as applied in a refrigeration plant where constant rather than
low temperature is required, I mix the carbon bi-sulphide with phenyl chloride in
the proportion of 9 of the bi-sulphide to 1 of the phenyl chloride. These proportions
may be varied as required by the work to be performed, as the modifications
produced on the evaporating liquid by the added liquid is in the same proportion as
the percentage of the added liquid.

page_text: 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:
First. The within described refrigerating liquid or mixture, composed essentially
of a volatile liquid mixed with other liquids, miscible with the volatile liquid, but
not a solvent thereof, substantially as set forth.
Second. The within described refrigerating liquid or mixture, composed
essentially of a volatile liquid, mixed with other liquid having a different degree
of mobility than the volatile liquid and miscible therewith, but not a solvent
thereof, substantially as set forth.
Dated this 7th day of July 1894.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents for Applicant.