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Патент USA US3022648

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Feb. 27, 1962
Filed May 6, 1959
2 Sheets-Sheet 1
FIG‘ 2
Feb. 27, 1962
Filed May 6, 1959
2 Sheets—Sheet 2
FIG. 4
United States Patent
_ rice
Patented Feb. 27, 1952
Howard E. Caswell, East Syracuse, and James W. Eu
dress, Syracuse, N.Y., assignors to Carrier Corporation,
Syracuse, N.Y., a corporation of Delaware
Filed May 6, 1959, Ser. No. 811,463
4 Claims. (Cl. 62-115)
in'the air conditioning-system utilizes a hermetic motor
which is cooled by economizer gas, thereis a tendency
for the liquid refrigerant in the economizer to ?ow
through the path normally provided for the ?ow of
gaseous refrigerant from the economizer to the motor
casing, so that a strong possibility that liquid refrigerant
will enter the motor casingexists. Liquid refrigerant
within the motor casing may be harmful to the windings
This invention relates broadly to air conditioning ap
of the motor and further, at start-up, may, by virtue of a
paratus. More particularly this invention relates to a 10 relatively low pressure existing in the motor casing, vapor
refrigeration machine utilized in air conditioning ap
ize and carry with it portions of the lubricant main:
paratus. Still more particularly this invention relates to
tained in the motor casing. This can occur to such an
a control employed on a refrigeration machine of the type
extent that the control normally provided for terminating
under consideration.
operation of the machine, due to low lubrication pressure,
In air conditioning equipment of the type to which 15 will interrupt operation of the machine to the discom
this invention pertains there is included a refrigeration
fort of the occupants of the enclosure.
machine employed to cool a medium which is delivered to
A related problem exists in equipment of the kind de
an enclosure to be supplied with conditioned air. Very
scribed wherein other means may be employed for cooling
often the medium to be supplied to the enclosure is water
the motor and in equipment where it is not necessary to
which has its temperature increased as it ?ows through 20 employ motor-cooling arrangements. In these instances
a closed circuit including, individual units spaced through
the line for conducting gaseous refrigerant from the
out the enclosure. Located in heat transfer relation with
economizer connects directly to the compressor. A re;
a coil in the circuit is the evaporator of the refrigeration
verse ?ow of refrigerant in these machines may cause
liquid refrigerantto be deposited ins the compressor in
machine, for the purpose of absorbing the heat and re
25 creasing the power requirement of the machine at the
ducing the temperature of the water.l a
,y The‘ refrigeration machine employed in the system
time the machineis, operated initially.
described inpludestheusual components such as a com
The chief object of the invention is the provision of
pressor, condenser, economizer and evaporator connected
a control for a refrigeration machine of the kind under
to form a circuit for the ?ow of refrigerant in the con
ventional manner. .In the case where the compressor in
conside'ration'which is operative to prevent ?ow of re
frigerant within the machine in a direction opposite the
the machine described is of the centrifugal type, and in
direction for which the ?ow is designed.
cludes a hermetic motor for driving the compressor, it
' , A further object of the invention is the provision of
has been found practical to utilize gaseous refrigerant
a refrigeration machine control of the type described that
from the economizer for the purpose of cooling the motor
is operative to vent the evaporator to a part of the re
driving the compressor. As is well known, the economizer, 35 frigeration system which may, temporarily, have a pres
,which in its broadest aspects may be described as reduc- sure below that of the evaporator, although under normal
ing the pressure of the refrigerant ?owing from the con
design conditions that part would have a pressure in excess
denser to the evaporator in two stages, preparatory to
of the pressure in the evaporator.
its supply to the evaporator, has generated therein a supply
Another object of this invention is the provision of a
of gaseous refrigerant through the commonly known 40 control for use in a refrigeration machine which is op
“?ashing o?” process. In other words, when the re~
frigerant is reduced in pressure from the existing con
denser pressure, a portion of the liquid refrigerant vapor
so that either substantial equalization of pressure between
,izes, chilling the remaining liquid refrigerant and ?owing
the two elements of the machine occurs or the pressure
erative to sense abnormal pressure conditions within the
evaporator and to vent the evaporator to the economizer
either to the motor casing or directly to the compressor, 45 in the economizer is supplemented so that the tendency
depending on the manner in which the motor driving the
compressor is cooled.
of the liquid refrigerant in this system to flow from the
evaporator is minimized.
Under certain operating conditions of the air con,
Another object of the invention is a method of op
Aerating a refrigeration machine so that the tendency of
.when the temperature of the ambient may ?uctuate 50 liquid refrigerant to reverse its ?ow in the machine under
through a given twenty-four hour period, the'norrnal pres
circumstances Where abnormal pressurerelationships are
lditioning apparatus, as for illustration, ,during periods
sure differences maintained in the refrigeration system
under operation are drastically changed. For example,
encountered is minimized.
This invention in attaining the objects set forth con-'
during the spring or fall season the ambient temperature
templates a refrigeration system including a compressor,
which determines the temperature of the condensing medi~ 55 a condenser, an economizer and an evaporator connected
um used in the condenser may drop during the evening or
to form a closed circuit, and means operable in response to
nivht hours. The enclosure being served by the air condi
a predetermined pressure relationship within the system
tioning system may still have a requirement for cooling,
for. preventing reverse ?ow of refrigerant from the
due to the presence of an excessive number of persons
evaporator to the economizer by venting the zone of great
within the enclosure or due to an excessive load such as 60 er pressure to a zone of lower pressure.
“lights or heat'generating equipment or machinery. Under
these circumstances, the pressure within the low side of the
Other objects and features of the invention will be ap
parent upon a consideration of the ensuing speci?cation
and drawings wherein:
system which includes the evaporator rises to a substan
FIGURE 1 is a diagrammatic representation of a refrig
tial level, while the pressure within the condenser is re—
duced substantially by virtue of the reduction in tempera 65 eration machine in an air conditioning system wherein
ture of the condensing medium. In some extreme cases
the machine is equipped with a control of the type forming
the temperature in thecvaporator may even exceed that
the subject of this invention;
FIGURE 2 is a partial perspective view of a portion of
in the condenser, to the extent that a tendency for liquid
refrigerant to reverse its ?ow in the machine occurs.
the evaporator and economizer of the refrigeration system
Thus, liquid refrigerant tends to ?ow backward through 70 shown in FIGURE 1 wherein certain parts are broken
away in the interest of clarity.
the machine from the evaporator to the economizer and/or
condenser. If the refrigeration machine being employed
FIGURE 3' is a view partly in elevation and partly i
the line 305 intothe motor casing and cause the harmful
To overcome the tendency of
‘ effects described above.
machine equipped with a modi?ed form of a control ar
rangement illustrating ,the invention.
a tendency is overcome, liquid refrigerant could ?ow'in
section illustrating the control valve used in the invention. 7
FIGURE 4 is a diagrammatic view of a refrigeration
?ow in this direction, applicant provides in the side of his
cooler a movable ?ap member 50 which is weighted and
For the'purpose or, illustrating the invention, an air cone
designed so as to open in the manner ofa check valve in
response to a predetermined relation between the econom
,ditioning system is diagrammatically illustrated iin-FIGp
URE 1. The system, includes a refrigeration machine in
izer and evaporator'pressure. In other words, once the
evaporator pressure exceeds‘ the economizer pressure the
' eluding a motor compressor unit 10 comprising 'a centrif
ugal compressor 11 and a hermetic motor'12 arranged to
drive the compressor; 'Gaseous' refrigerant in the refrig 10 member 50 will open causing the pressure in therevapora
tor to be reduced and the'pressure in the economizer to
erationv system is compressed bythe compressor 11 and
increase. Thus, the tendency for the liquid refrigerant to
forwarded through discharge line 13 to a condenser 14
flow from the evaporator to the economizer is overcome.
where it is liquefied as it passes in heat transfer relation
The member 50 illustrated in detail in’ FIGURE 3 in
'with' a condensing medium such as water ?owing in a
'closed circuit including coil 29, pump 20 and cooling 15 cludes mounting plate 60 having an opening 61 welded to
tower 28,_together with appropriate piping.
a portion of the cooler, a flexible member 62 formed of
neoprene secured to the mounting plate 60, a clamping
vThe lique?ed ‘refrigerant ?ows through line 15 to the
plate 63 and a support plate 64. The latter two are con
, economizer 16 where, it' isrsub'jectedrto a reduction in
nected to the ?exible member 62 to provide rigidity to the
assembly. The parts are designed so as to: swing pivotally
about fasteningelements 65 in response to a predeter
pressure causing portions of the liquid refrigerant to ?ash
'1 off or.vaporize and cool the remaining body of liquid
refrigerant. The cooled liquid refrigerant then ?ows
mined difference in pressure between the gas on the
from line 17 to; theevaporator 18 which has assembled
therein a coil 30 forming a part of a chilled water circuit,
to be later described. As heat is extracted from the water
in the coil 30 the liquid refrigerant is vaporized and ?ows
through‘suction line 19 to the compressor to complete the
opposite sides of the member 50. e‘
In FIGURE 4 there is illustrated a second embodiment
of'the' invention; The refrigeration~ machine illustrated
in FIGURE 4 is substantially identical to the machine
illustrated in FIGURE 1. Reference numerals indicat
ingjcertain‘ parts in‘FIGURE'l are 'used to- identify the
corresponding, parts shown in FIGURE-4. In the em;
_ As indicated above, a chilled water circuit includes coil
30 together with piping and a variable load represented at
40 which may beja unit comprising a coil for the dew of
bodiment illustrated in FIGURE 4,_ line 57 connects vthe
evaporator directly with the condenser, Flow’ of refrig
the chilled water and a fan for the purpose of providing
erant through line 57 is under the control of a valve mem
a supply of room air over the coil to reduce the tempera
ture of the room air for eventual recirculation to the room. , i
ber structurally and functionally similar to thatillustrated
‘ at50 in FIGURE 1. In the operation of the embodiment
In extracting heat’ from the room air the water leaving the
unit 49 has its temperature increased. The water is then 35 illustrated in FIGURE 4, a, pressure in the evaporator
which'is in excess of the pressure in the condenser causes
delivered by the pump 41 to the coil 30 for the purpose of
’ refrigerant to ?ow through line 57 thus building’ up pres
reducing its temperature. Theapparatus described is con
ventional‘and has enjoyed .widespreaduse in air condi- ~ sure in the condenserv while reducing the pressure in the
tioning system for a substantial period of time. .
Referring to the economizer construction,‘ it will be ob
Once a more normal pressure relationship
'I ‘' evaporator.
.40 between condenser and evaporator is’, obtained the tend
' served that the economizer 16 is divided into an upper
and lower chamber '25 and 26. A ?oaLvalve controlled
passage permits liquid refrigerant to ?ow from the upper
‘chamber. to the lower chamber. The upper chamber is
maintained at substantially high side or condenserpressurc
while the lower chamber 26 is at a pressure intermediate
' high side and low side pressure. As the liquid ?ows into.
‘ the chamber 26 portions thereof will -vaporize and the
ency for refrigerant flow from theevaporator 18 to the
economizer 16 is overcome and ?ow of refrigerant from
the condenser to the evaporator is assured.
Asindicated above this invention is operative under
circumstances where unusual pressure conditions exist
within the refrigeration system.‘ The unusual pressure
relationships are brought about by’ temperature differ
ences in the media supplied to the condenser and evap
orator for the purpose of liquefying and vaporizing re
vapor so created is utilized to cool the motor 12 by provid
.ing a path for its ?ow through line 30' from the 50 spectively, the refrigerant. To fully accomplish the ef'nl
ciencies available withthe control schemes presented the
' economizer chamber to the motor casing. After :the
~ pumps 20 and 41 should be energized to ‘cause ?ow within
'teconomizer gas ?ows in heat transfer‘with the motor, it is
their respective circuits prior to initiation of the ‘com
"delivered to the compressor at an intermediate stage of
compression through line 31 having a damper 33 respon
pressor. Thus,'?ow of refrigerant between the condenser
sive to a difference in pressure between the evaporator 55 and evaporator,.via lines 15, 17, economizer 16 and line
,7 and the economizer.‘ The purpose of this valve istojmain
tain a su?icient pressure within the ‘motor chamber; This
particular ‘control forms the subject of the United States,
patent application Serial No. 620,129, ?led November 2,
now issued
" 51 will occur and a refrigerating e?ect achieved.
While we have described a preferred embodiment of
our invention, it will. be understood our invention is not
limited thereto, since it may be otherwise embodied within
the scope of thefollowing claims.
as > United» Statesv Letters Patent 60
2,921,446, and assigned to the assigneerof' this invention.
1. Refrigeration‘ apparatus comprising a compressor,
. ~As pointed out’ above,-there are circumstances ‘during
a condenser, an economizer, an; evaporator a line con
which time the water ?owing in, the condenser cooling ' necting the economizer and the evaporator to pass liquid
'water circuit ‘may encounter a substantial 'reduction‘in
65 refrigerant to said evaporator, means providing an addi
temperature,.which, in.turn,‘causes a sharp reduction in
the condensing pressure. At the same time, the load im
tional passage between the evaporator and economizer
and .meansnormallyjclosing said passage, said last-men
posed upon the evaporator by virtue of excessive loading
tioned means being operative in response to a predeter
of the unit 40 may be substantially high ‘so that the term
mined ‘difference in pressure between the economizer and
pera'ture and ‘pressure'in the evaporatoris increased to‘a 70 the evaporator to open said passage toreduce the pressure
degree where the evaporator pressure either equalsv or ex
ceeds the condenser pressure. Under thesercircumstances,
of course,rthere is .a tendency forthe liquid refrigerant .
which has collected in the economizer, to ?ow in a direc
in the evaporator and increase the pressure in the econ
2. The invention set forth in claim 1 including a motor
‘including a casing operating said compressor, a line con
tron-opposite its normal intended. direction.- Unlesslsuch 75 necting the economizer and the casing providing a path
ous state and reducing the evaporator pressure by auto
for the ?ow of gaseous refrigerant formed in the econ
omizer to the casing to cool the motor.
3. The invention set forth in claim 2 including a line
connecting the casing and the compressor providing a
matically venting the evaporator to the economizer in
response to a predetermined pressure relationship be
tween the evaporator and the economizer.
path of ?ow for gaseous refrigerant ?owing through the
motor casing.
References Cited in the ?le of this patent
4. The method of operating a refrigeration machine
including a compressor, a condenser, an economizer and
a cooler connected to form a circuit for the ?ow of refrig
erant, which consists in the steps of supplying gaseous 10
refrigerant to the condenser for liquefaction therein, for
warding the refrigerant to the economizer wherein por
tions of the liquid refrigerant vaporize and cool the re
maining liquid refrigerant, delivering the cooled liquid
refrigerant to the evaporator for conversion to the gase 15
Carrier et a1 __________ _.. May 19, 193-6
Ashley ________________ __ July 4, 1939
Buchanan ____________ __ July 22,
Zwickel ______________ .. Feb. 24,
Jones _______________ _._ Mar. 24,
Rachfal ______________ __ June 2,
Kramer _____________ __ Dec. 15,
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