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Патент USA US2120559

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2,120,559
Patented June 14, 1938
UNITED STATES PATENT OFFICE
ABSORPTION REFRIGERATION
Burgess H. Jennings, Bethlehem, Pa., assignor
‘to The Philadelphia, and Reading Coal and
Iron Company, Philadelphia, Pa., a corpora
tion of Pennsylvania
No Drawing. Application April 20, 1937,
Serial No. 137,929‘
9 Claims. (01. 252—5)
at customary absorber temperatures of from 65°v
rI’his invention relates to absorption refriger
F. to about 110° F.
ation, and is particularly concerned with solvent
material for refrigerants in absorption type re
0
The absorber pressure is
essentially equivalent to that of the refrigerant
frigerating apparatus.
evaporator, which operates at'temperatures that
As is known to those acquainted with the art
of absorption refrigeration a solvent material is
may vary over a wide range but are ‘customarily 5
between 0° F. and 50° F.
It will be seen from the foregoing discussion
used to absorb a refrigerant vapor in one phase
that the solvent must be able to fulfill-its func
tions under varying temperatures and pressures.
- of operation of the machine, while in ‘another
phase the refrigerant is driven off from the sol
10 vent material because of heat supplied to the
solvent mixture. The refrigerant driven off is
condensed to liquid, and by suitable means may
accomplish refrigeration when it subsequently
vaporizes. The refrigerant vapor is then again
In addition, its freezing point should preferably 10
not be over about 10° F.
10 centipoises at 68° F. It must also be chemi
ticularly in regard to the common metals used 15 '
In the two-?uid type of machine, ‘me
chanicalimeans is required to circulate the re
frigerant against the different pressures of the
system, and only the refrigerant and its vapor
and the solvent, with very small quantities of
the vapor of the latter, are present in the ma
chine. In the three-fiuid type of machine an
inert gas, which is always gas, is also present
and is used to keep the pressure throughout the
machine essentially constant. The inert gas is
not essentially soluble in the refrigerant or sol
in refrigeration machine construction. It must
not form permanent chemical compounds with
the refrigerants used. Its speci?c heat should
be low for the greatest efficiency. It should be
capable of absorbing refrigerant at 90° F. ab
sorber temperature and at the evaporator pres
sure maintained, and should be capable of los
ing at 230° F. and at the condenser pressure
maintained, enough refrigerant to allow each '
pound of absorbent circulated a reasonable car- 25
rying capacity.
Its minimum boiling temper
vent of the machine.
ature should be about 240° (preferably above
The operation of two-fluid and three-?uid ab
sorption refrigeration apparatus is well known to
260° F.) at atmospheric pressure.
22 O those skilled in the art, so that no detailed de
scription of such apparatus need here be given.
It may be briefly noted that such apparatus com
prises a generator or still in which the solvent
mixture is heated and the refrigerant driven off
as a vapor, a condenser in which the refrigerant
vapor is condensed to a liquid‘ state, an evapo
rator in which the refrigerant liquid is vaporized
‘
I have discovered that tetrahydronaphthalene
(also known as tetralin) effectively meets the
requirements of a solvent in absorption refrig
eration. Particularly I have found that this sub
‘stance is a desirable solvent for the refrigerant
methyl chloride under the conditions prevailing
in absorption type refrigerating systems. In ad- 5'
dition, this substance may be used in absorption
refrigerators as a solvent for other volatile,
at reduced pressure, and extracts heat from the
medium which is to be cooled, and an absorber in
chemically stable, halogenated hydrocarbon re
frigerants, such‘as ethyl chloride, dichlorodi
which the‘ refrigerant vapor containing, heat
?uoromethane (CClzFz), methyl bromide, mono- .
fluorodichloromethane (CHClzF) , dichlorotetra
withdrawn from the refrigerated medium is
again dissolved in the solvent.
'
cally stable at temperatures below 270° F., pare
' absorbed by the solvent and the cycle repeats
itself.
It should have a vis-
cosity preferably not substantially higher than
_
A refrigerant solvent must meet satisfactorily
widely varying special conditions in absorption
iiuoroethane
(CZCIZFU,
mono?uorotrichloro
methane (CFCla) ,and. dichlorethylene (C2H2C12) .
With respect to the properties of the refriger
ant employed, it may be noted that the refrig- 45
erant should be capable of condensation at tem
to 270° F. are commonly employed. The char- ' vperatures not greatly in excess of 100° F. The
acteristics of the solvent should be such that in critical temperature value should usually not be
lower than 130° F. vaporization must be readily
I
this temperature range the refrigerant inv solu
possible at the pressures for which the system is 50
50 tion can, to a great extent, be removed and pass
designed at temperatures as low as 0°
for
off as a gas into the condensing part of the unit.
conventional refrigeration, and usually some
Condenser and generator pressures are essential
1y equivalent. Furthermore, the solvent in the what below 50° F. for air conditioning work.
It may be noted in passing that many refriger
absorber of the unit should be capable of absorb
55 ing an appreciable quantity of the refrigerant ants are in the vacuum region during evapora- .
In the ?rst place, in
the generator or still, temperatures of from 200°
' refrigerating apparatus.
I 2
2,120,559
' tion and in some of them even during con
densation, but that many others may operate in
both regions or altogether in the positive pres
sure region.
The atmospheric boiling point of
a substance is thus not necessarily an index of
its suitability as a refrigerant because of the
possibility of operating in the vacuum region.
‘ However, atmospheric boiling points above 120”
F. do not usually represent good refrigerants.
10
The chemical tetrahydronaphthalene to which
I refer has the empirical formula C1oH12, consist
ing structurally of two'carbon rings constituting
naphthalene, one of the rings being completely
hydrogenated (except for the double bond com
15 mon to the two rings), and the other ring un
changed.
This structural formula may be illus
trated as follows:
'
I claim:
~
1. A refrigerant mixture for absorption re
frigerators,‘ said mixture comprising a hydro
genated naphthalene as a solvent and a volatile
chemically stable refrigerant soluble in said ‘sol
vent.
"
-
~-
~
2. A refrigerant mixture for absorption re
frigeratprs, said mixture comprising a hydro
genated naphthalene as a solvent and a volatile.
chemically-stable, halogenated .hydrocarbon re
frigerant soluble in said solvent.
,
3. A refrigerant mixture for absorption re
frigerators, said mixture comprising a hydro
genated naphthalene having at least two double
bonds replaced by hydrogen atoms as a‘solvent 15
and a volatile chemically stable halogenated
hydrocarbon refrigerant soluble in said solvent.
4. A refrigerant mixture for absorption re
frigerators, said mixture comprising tetrahydro- '
naphthalene as a solvent and a volatile chemi 20
20
cally stable refrigerant soluble in said solvent.
5. A refrigerant mixture for absorption re
The chemical is a rather stable liquid, boiling at
25 about 206° C. and freezing at about —25° C. It
is practically non-toxic.
'
My invention also includes decahydronaphtha
lene (known also as decalin) which is suitable
and satisfactory as a solvent for-absorption re
frigeration. This chemical, the boiling point of‘
which is about 190° C. and the melting point
about —10° C., has the empirical formula CmCia,
and structurally consists of two carbon rings
' constituting naphthalene both of which are com
pletely hydrogenated.
35 illustrated as follows:
This formula may‘ be
CH:
ERs
I o-o ' ‘F/min\
40
3 /C
OH
frigerators, said mixture comprising decahyd'ro
naphthalene as a solvent and a volatile chemi
cally‘ stable refrigerant soluble in said solvent. 25
6. A‘ refrigerant mixture for absorption re~
frigerators, said mixture comprising vmethyl
chloride as the refrigerant and a hydrogenated
naphthalene as'the refrigerant solvent.
7. A-refrigerant mixture for absorption re 30
frigerators, comprising a hydrogenated naphtha
lene as a solvent and a volatile, chemically
stable, halogenated aliphatic hydrocarbon re
frigerant soluble in said solvent.
8. A refrigerant mixture for absorption re
frigerators, comprising a hydrogenated naphtha
lene as a‘ solvent and a volatile, chemically
'stable, halogenated hydrocarbon'refrigerant hav
/
on:
i
It is to be understood that adulteration of the
solvent in its pure form, either by virtue of com
mercial impurities or because of addition of other
solvent material is within the scope of my in
vention as de?ned by the ensuing claims.
ing not more than two carbon atoms soluble in
said solvent.
40
9. A refrigerant mixture for absorption re
frigerators, comprising a hydrogenated naphtha
lene as a solvent and a volatile, chemically
stable, halogenated methane refrigerant solub
in said solvent.
'
.
'
‘BURGESS H. JENNINGS.
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