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Патент USA US2050650

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Aug. 11", 1930.v
J_ R, FEHR
W
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2,050,650
'REFRIGERAT ING APPARATUS
Filed May 30, 1933
2 Sheets—Sheet l
Aug. 11, 1936.
JKRFEHR
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REFRIGERATING APPARATUS
Filed May 30, 1933
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2,050,650
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2 Sheets-Sheet _2
Patented Aug. 11, 1936
2,050,650
UNITED STATES PATENT OFFICE 0
2,050,650
REFRIGERATING APPARATUS
John Ralph Fehr, Dayton, Ohio, assignor, by_
mesne assignments, to General Motors Cor
poration, a corporation of Delaware '
Application May 30, 1933, Serial No. 673,720
17 Claims.
(01.62-4)
Fig. 2 is a top view of the control portion or
This invention relates to refrigerating appa
ratus and more particularly to mechanisms for ~ means in Fig. 1;
defrosting or removing the frost from cooling
Fig. 3 is an enlarged end view of the control
units of refrigerating apparatus.
'
In the use of household refrigerator cabinets,
it is customary to maintain the temperatures
of the cooling unit below freezing to provide ice
cubes and in some instances frozen comestibles
as well as to cool the air within the refrigerator
10 cabinet. .The operation of the evaporator at a
_ temperature below freezing, causes frost to col
‘lect upon the air cooling surfaces of the cooling
unit. This frost acts as an insulator between the
cooling unit and the ambient air and reduces
15 the ef?ciency of the heat transfer between the
erant is lique?ed and collected in a receiver 22.
Fromv the receiver, the liquid refrigerant is for
warded through the supply conduit 23 to a ?oat
controlled ?ooded evaporator 24 which is located 15
been accomplished by merely discontinuing the
operation of the refrigerating apparatus. While
partment 25 causing the evaporation of liquid
refrigerant, which evaporated ‘refrigerant is re- 20
frequently happens that the user forgets to re
turned to the compressor through the return con
duit 21. The compressor 20 is driven by the elec
sence of refrigeration.
‘
within the food compartment 25 of a refriger
from the air within the interior of the food com
tric motor 28 through suitable pulley and belt
means 29. The electric motor 28 is provided with
I 25
The objects of my invention are to eliminate the
objectionable features of former methods of de
electrical supply conductors 30 and 3|.
frosting by the provision of defrosting mecha
nism which will automatically restore the refrig
erating apparatus to its normal operation after
the defrosting is completed; and particularly a
ing means 24 is controlled by a control means,’
mechanism which may be operated as a fully
- automatic mechanism or a semi-automatic mech
anism for defrosting.
It is a further object of my invention to incor
porate such a defrosting mechanism into and
with the temperature regulating mechanism so
that all may be operated and controlled by the
same operating member‘ and so that the defrost
ing mechanisms are rendered ineffective when the
40 temperature regulator is moved to provide colder
than normal cooling unit temperatures.
It is another object of my invention to control
all of ‘these defrosting devices as well as the tem
perature regulator by a single manual control
means and to so construct this manual control
means so (that only one of these devices will be
e?‘ective at a time.
Further objects and advantages of the present
invention will be apparent from the following de
50 scription, reference being had‘ to the accompany
ing drawings, wherein a preferred form of the
In the drawings:
The temperature of the ?ooded type evaporat
generally'designated by the reference character
32, which is in series with the electrical supply
conductor 3| so as to control the operation of the
electric motor. The control means 32 is connect
ed to the return conduit 21 by a suitable tube
33 so that the control means operates according
to the pressure within the evaporator 24, which
pressure is proportional to the temperature of the 35
evaporator. The control means 32 therefore con
trols the starting and stopping of the compressor
according to the temperature and pressure of the
evaporator 24.
h
'
,
40
Referring now particularly to the control
means 32, there is provided a platform 35 upon
which is mounted a metal bellows 36, the in
terior of which is connected to the tube 33.
Above the bellows 36 is a lever 31 which is con- 45
nected tothe bellows 36 by a bellows follower 38.
Surrounding the bellows 36 is a sort of a cage
39 which is supported by the platform 36 and
which is provided with a bearing 40 which sup
ports a pivot pin 4| for pivotally supporting the 50
end of the lever 31. The opposite end of the
lever 31 is connected to a snap acting switch ‘
present invention is clearly shown.
_
g
» Fig. 1 is a view of a refrigerating apparatus
55
5
of Fig. 3.
Referring to the drawingsand more particu
larly to Fig. 1 there is shown a refrigerating sys
tem including a compressor 20 for compressing
‘the refrigerant and forwarding the compressed 10
refrigerant to a condenser 2| where the refrig
ator cabinet 26. The cooling unit 24 absorbs heat
store the apparatus, resulting in a prolonged ab
35
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~ Fig. 4 is a sectional view along the line 4--4
air and the cooling unit.
This frost must be removed from the cooling
unit or coil periodically and in the past this has
20 this method of removing frost is quite simple, it
30
means shown in Fig. 1; and
partly diagrammatic embodying my invention;
mechanism. This snap acting switch mecha
nism comprises a lever 42 which is pivotally
mounted upon a pin 43 which is ?xed to the 55
2
2,050,650
main lever 31. This secondary lever 42 is made
is moved upwardly from a position beneath the
in two parts, one on either side of the lever 31
and these parts are connected together by suit- ‘
cam roller 46 to a position above the roller so
that the secondary lever 42 is caused to turn
counterclockwise about its pivot pin 43 to move
able rivets 44 so that the two parts act as a unit.
At one end of this lever 42 there is provided
the movable contact 66 into contact with the
a cam 45 which is riveted thereto and which is
stationary contact 61.
This closes the circuit to
‘adapted to co-act with a spring pressed cam the electric motor 28 and starts the operation
roller 46 mounted upon the upper end of a of the compressor 20. The operation of the
spring pressed lever 41 and pivoted at its lower ’ compressor 28 removes the vapor from the cool
ing unit 24 and condenses this vapor in the con 10
10 end upon a pin 48 which has its end mounted in
an inverted U-shaped standard 49. The lever
denser 2|. This in turn causes the pressure
41 is urged in a counter-clockwise direction
within the return conduit 21 to be lowered and
about its pivot pin 48 by a spring 12 so that the
this lowering of the compressor tends to con
roller 46 is resiliently held against the cam 45. tract the bellows 36 against the tension of the
range adjusting springs 5‘! and 58. The main
15 The standard 49 rests upon the platform member
35 and at its upper end carries a differential
adjustment means 50 which contains a movable
plunger 5| which is spring pressed against a
shoulder within the differential adjustment
20 means. The lower end of this plunger 5| is
adapted to engage the upper portion of the ex
treme end of the main lever 31 when this main
lever end is in its upper position. However, when
the main lever is moved to its lower position, the
25 shoulder within the differential adjustment
means prevents the plunger from continuing to
follow the main lever in its downward movement.
In this way the lever 31 is only affected by the
differential adjustment means at its upper limit
30 to provide a differential adjustment.
A range adjustment means is also provided
for the main lever 31. This range adjustment
lever 31 moves downwardly because of the con
traction of the bellows 36 and causes the cam 45
to move from the position above the cam roller
56 to a position below the cam roller 46.
This
cam roller 46, is, of course, pressed against the 20
surface of the cam 45 by the spring 12 which
urges the cam roller lever 41 in the counterclock
wise direction about the pivot pin 48. The urg
ing of the cam roller against the upper face of
the cam 45 causes the lever 42 to move in a 25
clockwise direction ‘about its pivot pin 43 to
open the switch contacts 66 and 61.
e]
In order to provide lower temperatures of th
evaporator 24 for freezing purposes, there is pro
vided a temperature regulator. This tempera 30
ture regulator is mounted upon an L-shaped
bracket member 15 which has its lower horizon
means comprises a vertical rod 55 which has its
tal portion fastened beneath the platform 35.
upper and lower ends threaded and which is The upper vertical portion is provided with a
fastened at its upper end by means of a pin 56
dial ‘I6 and a.rotatable handle 11 which is ?xed
to the main lever 31. The rod 55 of the range upon the end of a shaft 18 rotatably mounted‘
adjustment means passes through the platform in the vertical portion of the L-shaped bracket
35 and is surrounded by a large spring 51 above 15. The shaft 18 extends a considerable distance
the platform and a small spring 58 below the back of the vertical portion of the L-shaped
bracket 15 and has a temperature regulating
40 platform. The tension of the spring 51 is con
trolled by a pair of nuts 59. one serving as an
spring 19 having a portion coiled thereabout.
adjusting nut, and the other as a lock nut. Like
The forward end of this coil portion extends into
wise, the tension of the spring 58 is controlled -a slot 8| which extends through the greater
by a pair of nuts 60, one serving as an adjusting
portion of the 'shaft 78. Extending from the
other-end of the coil portion of the spring is a
45 nut and the other as a lock nut. By means of
the tensioning of the springs 51 and 58, the straight portion which is adapted to engage,
pressure required within the bellows 36 in order when moved into position, an extension of the
to move the lever 31 in one direction or the
other is controlled.
50
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The end of the secondary lever 42 opposite the
cam 45 is connected by a long pin 64 to an in
sulating link 65 which in turn is connected by
means of a pin to a movable contact member 66.
This movable contact member 66 is adapted to
55 cooperate with a stationary contact 61 mounted
upon the platform 35. In order to guide the
movement of the movable contact 66 this movable
contact member is connected by means of copper
strips 68 which are pivoted at their opposite end
60 to an insulating member 69 which is mounted
beneath an aperture 10 in the platform 35. One
portion of the electrical supply conductor 31 is
connected to'one of the copper strips 68 while the
other portion is connected to the stationary con
tact 61.
'
By means of this mechanism, as the tempera
ture and pressure within the cooling unit 24 rises,
the bellows 36 expands under control of the
springs 51 and 58 so that the free end of the
main lever 31 moves upwardly and contacts the
lower end of the plunger 5| forming a part of.
the differential adjustment means. As the main
‘lever 31 continues its upward movement, the
plunger 5| is moved upwardly against the tension
76 of its own spring member and ?nally the cam 45
pivot pin 43. When this straight end portion
of the temperature regulating spring is moved
into contact with the pivot pin 43 it assists the 50
bellows in moving the switch to closed circuit
position and thus causes the electric motor to
operate for longer periods of time so as to re
duce the average temperature of the evaporator
24 below‘ normal. The handle '11 is provided
with an engaging pin beneath its knob which is
adapted to engage apertures 82 extending around
the outer portion of the dial 16. Some of these
apertures are designated 1, 2, 3, 4, and 5 which
designate the various ‘temperature regulating
positions. When the handle 11 is moved to num
ber 1 position, the free end of the temperature
regulating spring 19 engages the pivot pin 43 to
apply pressure thereon in order to urge it up
wardly with a certain tension. When the handle
11 is moved to number 2 position, an increased
tension or pressure is applied to the pin 43,
while when the handle is moved to position 3, 4,
and 5, an increased pressure or tension upon the
pin 43 is made in each case. Thus, by this de- I
vice the temperature of the cooling unit 24 may
be lowered at any time below the normal aver
age temperature in ?ve different degrees, any
of which may be selected.
AS Stated in the beginning of the speci?cation,
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the evaporator 24 is normally maintained below these devices are objectionable. For instance,
when there is provided a completely automatic
freezing temperatures. This causes frost to ac
cumulate upon the surface of the evaporator and defrosting device which provides periodic de
this frost acts as a sort of an insulator. By frosting cycles automatically, a defrosting cycle
acting as an insulator, the efficiency of heat I may occur when it is desired to freeze ice cubes
transfer is reduced between the air in the cabinet or when there is a large amount of food within
and the liquid refrigerant within the cooling unit the refrigerator cabinet which is likely to be
spoiled by such defrosting. With the other type
24. This also lowers the entire operating effi
ciency of the refrigerating system. In order to \ of automatic defrosting, which is sometimes
called semi-automatic, defrosting may not be
10' maintain a reasonable operating ei?ciency it is
therefore necessary to remove this frost from the performed sufficiently often and the length of
defrosting period may not be sufficient if de
cooling unit whenever it builds up to a substan
tial amount. The most convenient way of doing frosting has not been attended to for a great
this is to permitthe temperature of the evaporator length of time. Thus, it will be seen that there
to rise above the freezing temperature and thus are objectionable features to each type of de 15
cause the frost to melt from the cooling unit. frosting but there also seems to be a'place for
each of these types of defrosting.
However, this is not without objectionable fea
I therefore provide in my control means a pro
tures. The increase of the temperature of the’
evaporator of the cooling unit 24 above freezing vision for each of these types of defrosting means,
and, further, so combine these defrosting means 20
temperatures causes the temperature to be in
creased within the cooling compartment 25 and
thus increases the danger of food spoilage; hence
with the ‘temperature regulator so that all may be ,
when there is a large amount of food within the
late these devices by means of a regulating cam
so that only one will be effective at a time. Thus
when the handle 1'! is in any one of the cold con
trol positions, no defrosting will occur. When
cabinet which might be damaged by the increase
in temperature, it~is undesirable to have any
defrosting at such a time. For this reason, it is
often desirable to wait until the food supply
within the refrigerator is low before. defrosting
is attempted. The increase of the temperature
30 of the evaporator above the freezing point also
delays or prevents the freezing of ice cubes,
desserts, and other comestibles within the evap~
orator or cooling unit 24. This increase in tem
perature may also cause the melting of any ice
cubes which maybe in the evaporator during
a defrosting period. Some of the other objec
tions to this defrosting have been that the house
wife does not defrost her cooling unit regularly
‘ enough or often enough and also that sometimes
she begins a defrosting period and then forgets
40 to terminate this defrosting period at the proper
time when’ the cooling unit has been completely
defrosted.
Y
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In the past it has been customary to defrost
the cooling unit or evaporator by the shutting off
of the refrigerating apparatus for a period of
time su?icient to raise the temperature of the
evaporator above freezing for a long enough time
to cause the frost to completely melt from the
cooling unit. Thereafter it was necessary to
again restart the apparatus. While this ar
rangement was fairly satisfactory in that it per
controlled by the handles" and further corre
the regulating handle ‘H is in full automatic de-.
frosting position, only the periodic automatic de
frosting cycles will occur. When the regulating
handle 11 is in semi-automatic position, only the
semi-automatic defrosting period will occur.
While, if the handle 11 is moved to full defrost or
off position, the operation of the refrigerating
apparatus will be stopped until such time as the
regulating handle ‘ii is moved to one of the other
positions.
_
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_ In order to provide a means for performing a
fully manualdefrost, that is, by shutting off the
refrigerating apparatus, I provide a sheet metal
arm 90 which is keyed to the regulating shaft 18. 40
This arm is substantially in‘alignn’ient with the
regulating handle 11 and when the regulating
handle 'I'l is moved clockwise to the off position,
the end of this arm 90 engages the projecting
end of the pin 64 so as to forcibly move the switch
contact 66 to open position and ‘to hold it there as
long as the regulating handle Tl remains in this
position. This arm 90 therefore serves to lock
the switch in open position.
In order to provide means periodically defrost- .
ing the cooling unit, I provide a ratchet wheel ")0
slidably and rotatably mounted upon the pivot
mitted the defrostingof the refrigerator at any _ pin 43. This ratchet wheel is, of course, moved
time desired by the housewife and for any period up and down by the movements of the main lever
37.‘ Positioned in the path of movement of the
' desired by her, it was found that this defrosting
was not performed often enough or regularly ratchet wheel I00 is a spring pressed pawl [0|
enough and‘ that the defrosting periods were which is p'voted upon the pin 48 and which is
often made too long and the food compartment urged against the stop pin I02 by a spring I03.
denied refrigeration for too great a time. In Therefore when the ratchet-wheel Hill is moved
order‘ to overcome these difficulties, I provide
60 automatic means for performing this defrosting
'which will insure that the apparatus will be
restored at the proper time. In one type of such
automatic means, the defrosting period is man
ually initiated, that is, the housewife is required
to set the defrosting mechanism whenever she
desires a defrosting period to occur. but mech
I anism is provided for terminating such a defrost
ing period automatically after the cooling unit
reached a certain temperature which ordinarily
75
insures complete defrosting. -The automatic
means also provides defrosting ‘cycles completely
automatically at periodic intervals, if desired.
Each of these forms serves excellently at certain
times if properly attended to. At other times‘
downwardly by the main lever 31 it will engage
the pawl IM and be rotated a distance of one
tooth. This rotation of the ratchet wheel M0 is
controlled by an aligning detent spring 104 which
resiliently engages the teeth of the ratchet wheel.
This spring which is in the form of a leaf spring
is riveted to the main lever 31.
The ratchet wheel I00 carries a pin I05 near
its periphery, which pin projects from opposite
sides of the ratchet wheel.
This pin I05, is, of ’
, course, moved step by step or tooth by tooth, '
about the pin 43 just as is the ratchet wheel “)0.
In order to periodically increase the temperature
of the cooling unit automatically, I cause this
pin I85 to periodically engage a prong I 06 which
forms a part of the forked end of an arm I01 75
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which is pivoted upon the pin 4| which also
serves as a pivot pin for the main lever 31. This
arm I 01 is pulled downwardly by a tension spring
I08 which is hooked at its lower end to an eye
screw I09 threaded into the platforms 35 and pro
vided with a lock nut H0. The upper end of the
spring I08 is hooked on to an eye screw I I I which
passes through a passage I I2 provided in the arm
. I01.
Resting on the upper face of the arm IN
10 is an adjusting nut H3 which is threaded upon
the eye screw I II and is provided with a lock nut
II4. In order to prevent the spring I08 from
pulling the arm downwardly too far and to pre
vent it from coming into engagement with the
15 teeth of the ratchet wheel I00‘, there is a stop I05
upon the cage 39 of the bellows which engages
the bottom of the arm I01 to limit its downward
movement.
As stated before, the ratchet wheel I00 is slida
20 bly and rotatably mounted upon the pivot pin 43.
In order to control the lateral movement of the
ratchet wheel I00, there is provided a fork I20,
the prongs of which are turned inwardly to en
gage the sides of the ratchet wheel. These
prongs remain between the center of the ratchet
wheel and the path of movement of the pin I 05
so that there is no interference between the
prongs of the fork I20 and the pin I05.
The fork
I20 is pivoted at its lower end to an ear I2I
which is turned out from the inverted U-shaped
standard 49. This fork is also connected to a
slide bar I22 provided with a forked projection
I23 extending upwardly at an angle of about 45°.
The movement of the slide bar I22 is controlled
by the pin I24 mounted in the ear I25 extending
from the standard 49. This pin I24 extends into
a slotted aperture I25 formed in the slide bar I 22.
The forked end of the projection I23 engages a
regulating cam I28 mounted upon the end of the
regulating shaft ‘I8. This regulating cam is in
the form of a disc whose periphery extends into
the notch which forms the forked end of the pro
jection I23. The periphery of this cam I28 is
warped or bent laterally toward the dial "I6 to
form a nose I29.
When the cam I28 is rotated
by the handle TI the nose enters into the notch
formed in the end of the projection I23 and moves
the slide I22 toward the dial ‘I6 to pivot the fork
I20 counterclockwise in order to move the ratchet
wheel toward the dial ‘I6. By moving the ratchet
wheel towards the dial 16, the pin I05 is caused
to move directly beneath the projecting prong I06
at the end of the arm I01 in a generally elliptical
path. Should this pin I05 and the prong I06
be in exact alignment when this shifting of the
ratchet wheel is made, the pin I05 will cam the
prong I06 and the arm I01 upwardly by reason of
the inclined surface I03 which is provided on the
inner side of the prong I06. Thus, the prong
(10 will be lifted on top of the pin I 05.
When the ratchet wheel is in this position, it is
rotated as usual step by step, that is, tooth by
tooth, by the pawl IOI. It also reciprocates as
usual with the main lever arm 31. This indexing
takes place when the lever 31 is moved to its
lower position and once every revolution of the
‘ratchet wheel I00, the pin I 05 is indexed to a
position directly beneath the prong I06. On the
next upward movement of the lever 31, the top of
the pin I05 comes into engagement with the lower
?at surface prong I06 and this imposes an addi
tional burden upon the main lever 31 so as to in
crease the pressure required within the bellows
36 to move the switch to closed circuit position.
7 This increase inv burden is caused for the reason
that the pin I05 is required to lift the arm I01
against the tension of the spring I08. This in
crease in pressure required in the bellows to
cause the switch to move to closed circuit posi
tion delays the starting of the refrigerating ap
paratus for the next running period and thus
causes the temperature of the evaporator to rise
above the freezing point. The tension of the
spring I08 is so adjusted by the nut II3 that the
pressure required to close the switch at this time
is one which corresponds to a temperature with_
in the evaporator of several degrees above freez
ing, for example, about 34 to 36° F.
This mechanism provides a periodic defrosting
cycle each time the pin is moved into position
beneath the prong I05 or, in other words, once
every revolution of the ratchet wheel I00. This
occurs entirely automatically so long as the han
dle 'I'I remains in full automatic position. How
ever, as soon as the handle ‘I1 is moved to one of '
the other positions on the dial the regulating
cam I28 moves the ratchet wheel and the pin I05
away from the prong I06.
In order to provide the other form of auto
matic defrost, which is sometimes called semi 25
automatic defrosting, the ratchet wheel is moved
in the opposite‘ direction from its central posi
tion (shown in Fig. 3). When in this position
the opposite end of the pin I05 is caused to en—
gage the other prong I35 which forms the other 30
part of the forked end of the arm I07. This
other prong has a somewhat more complex struc
ture than the prong I06. This prong I35 has a
cam or inclined surface I36 on its inner face
which when engaged by the end of the pin I05 35
in its lateral movement when in alignment there
with causes the lifting of the arm I01. Adjacent
this inclined surface I36 and directly opposite
.the prong I06 there is a shoulder I3'I which forms
a resting place for the pin I05. At the side of 40
this shoulderthere is provided a vertical circuit
I38 which acts as a guide and a stop to limit the
movement of the pin and the ratchet wheel away
from the dial ‘I6. It is desired that when in this
position there will be provided a plurality of de 45
frosting cycles, that is, cycles in which during a
portion of the time, the temperature of the cool
ing unit will be raised about the freezing point
and after the termination of a predetermined
number of these defrosting cycles that the periods
be restored to normal operation. In order to do
this, another cam surface I39 is provided at the
rear of the guiding surface I 38.
This cam sur
face I 39 is adapted when the ratchet wheel is
indexed a predetermined number of times to
move the ratchet wheel to its central position.
When moving the ratchet wheel to its central or
neutral position, the fork I20 is also moved there
by moving the slide bar I22 and the projecting
arm I30 forming part of the slide bar I22 acts
against the semi-automatic defrosting nose I4I
upon the periphery of the cam I28 in order to
cause the cam to be rotated and also the handle
‘I1 to neutral position designated by “N”. In the
semi-automatic position, there is no aperture pro
vided to detain the regulating handle 'I'I in that
position but merely a slight depression which may
be overcome by the cam surface I39 upon the
prong I35 which moves the ratchet wheel to neu
tral position. When the regulating handle is
thus moved to neutral position the switch means
is ‘again set for operation without any defrosting
or colder temperature regulation until the handle
11 is reset.
It will thus be seen that I have provided a re 75
2,050,650
5
orating means, means for controlling the appara
tus for maintaining the evaporating means at a
normal average temperature, automatic means
freezing purposes, as well as three different de
frosting mechanisms, each of which is individu-_ for periodically increasing the average temper
ally controlled by a single regulating handle ature of the evaporating means above the normal
frigerating apparatus with a control means pro
viding for suitable temperature regulation for
which also serves as an indicator and this handle,
together with the cam I28 so correlates these de
vices so that only one is effective at a time.
While the form of embodiment of the inven
10 tion as herein disclosed, constitutes a preferred
form, it is to be understood that other forms
might be adopted, all coming within the scope of
the claims which follow.
What is claimed is as follows:
15'
1. Refrigerating apparatusincluding a refrig
erant liquefying means and a refrigerant evapo
rating means, means for cyclically controlling
the apparatus for maintaining the evaporating
means at a normal average temperature, means
responsive to the cyclical operation of the appa
‘20 ratus
for automatically, at predetermined inter
vals, increasing the average temperature of the
evaporating means above the normal average
temperature for providing periodic defrosting
cycles, manually initiated means operable at will
for providing defrosting cycles, said last men
tioned means including automatic means for re
storing the apparatus to the normal control of
said control means.
2. Refrigerating apparatus including a refrig
erant liquefying vmeans and a refrigerant evapo
ratingmeans, means for controlling the appa
ratus for maintaining the evaporating means at
a normal average temperature, means for auto
35
matically, at predetermined intervals, increasing
the average temperature of the evaporating
means above the normal average temperature for
providing periodic defrosting cycles, manually ini
tiated means operable at will for providing de
frosting cycles, and means operated by the change
40
in temperature in the apparatus during a defrost
ing cycle for terminating a defrosting cycle.
3. Refrigerating apparatus including a refrig
erant liquefying means and a refrigerant evapo
rating means, means for cyclically controlling the
apparatus for maintaining the evaporating means
at a normal average temperature, means for auto
matically, at predetermined intervals, increasing
the average temperature of the evaporating
means above the normal average temperature for .
providing periodic defrosting cycles, manually
initiated meansoperable at will for temporarily
varying from normal the temperature of the
evaporating means for a plurality of cycles for
providing a plurality of altered cycles and there
after automatically returning the apparatus to
normal operation.
I
4. Refrigerating apparatus including a refrig
erant liquefying means and a refrigerant evapo
rating means, means for cyclically controlling
the apparatus for maintaining the evaporating
means at a normal average temperature, means
for automatically, at predetermined intervals, in
creasing the average temperature of the evapo
average temperature for providing periodic de
frosting cycles, manually initiated means oper
able at will for temporarily increasing the tem
perature of the evaporating means for providing
defrosting cycles and thereafter automatically
returning the apparatus to normal operation, and
selectively operable common means for selectively
controlling the periodic means and said manu
ally initiated means.
‘
6. Refrigerating apparatus including a refrig
erant liquefying means and a refrigerant evap
orating means, means for controlling the appa
ratus for maintaining the evaporating means at
a normal average temperature, automatic means
for periodically increasing the average temper-_ 20
ature of the evaporating means above the normal
average temperature for, providing periodic de
frosting cycles, manually initiated means oper
able at will for temporarily increasing the tem
perature of the evaporating means for providing 25
defrosting cycles and thereafter automatically re
turning the apparatus to normal operation, and
common selective means for controlling the pe
riodic. means and the means operable at will so
30
that only one will be effective at a time.
'7. Refrigerating aparatus including a refriger
ant liquefying means and a refrigerant evap
orating means, means for controlling the appa
ratus for maintaining the evaporating means at
a normal average temperature, automatic means 35
for periodically increasing the average temper
ature of the evaporating means above the nor
mal average temperature for providing periodic
defrosting, a ?rst means operable at will for tem
porarily lowering the temperature of the evap
orating means below the normal average tem
perature for freezing purposes, a second means
40
operable at will for providing defrosting cycles
and thereafter automatically returning the ape
paratus to normal operation, and common means
for controlling the ?rst and the second means
operable at will.
8. Refrigerating apparatus including a refrig
erant liquefying means and a refrigerant evap
orating means, means for controlling the appa
ratus for maintaining the evaporating means at
a normal average temperature, automatic means
for periodically increasing the average temper
ature of the evaporating means above the nor
mal average temperature for providing periodic
defrosting, a ?rst means operable’ at will for
temporarily lowering the temperature of the evap
orating means below the normal average tem
perature for freezingpurposes, a second means
operable at will for providing defrosting cycles
and thereafter automatically returning the appa
ratus to normal operation, and common means
for controlling the periodic means and the ?rst
and second means operable at will.
9. Refrigerating apparatus including a refrig 65
rating means above the normal average tempera- Y erant liquefying means and a refrigerant evap
ture for providing periodic defrosting cycles,
~manually initiated means operable at will for
temporarily increasing the temperature of the
evaporating means for providing a plurality of
defrosting cycles and thereafter automatically
returning the apparatus to normal operation,
said manually initiated means rendering said
periodic means inoperative for succeeding cycles.
5. Refrigerating apparatus including a refrig
75 erant liquefying means and a refrigerant evap
orating means, means for controlling the appa
ratus for maintaining the evaporating means at
a normal average temperature, automatic means
for periodically increasing the average temper 70
ature of the evaporating means above the nor
mal average temperature for providing periodic
defrosting, a ?rst means operable at will for tem
porarily lowering the temperature of the evap
orating means below the normal average tem 75
6
2,050,650
perature for freezing purposes, a second means
operable at will for providing defrosting cycles
point for each successive cycle for a predeter
mined number of cycles for defrosting purposes
and thereafter automatically returning the ap
and thereafter automatically returning the re
paratus to normal operation, and common means
for controlling the ?rst and the second means
operable at will so that only one will be'effective
frigerating apparatus including the control
at a time.
erant evaporating means and a refrigerant liq
uefying means, control means for controlling the
liquefying means to maintain a normal average
10. Refrigerating apparatus including a re
frigerant liquefying means and a refrigerant
10 evaporating means, means for controlling the
apparatus for maintaining the evaporating means
at a normal average temperature, automatic
means for periodically increasing the average
temperature of the evaporating means above the
15 normal average temperature for providing peri
odic defrosting, a ?rst means operable at will for
temporarily lowering the temperature of the
evaporating means below the normal average tem
perature for freezing purposes, a second means
operable at will for providing defrosting cycles
and thereafter automatically returning the ap
paratus to normal operation, and common means
for controlling the periodic means and the ?rst
and second means operable at will so that only
one will be effective
11. Refrigerating
frigerant liquefying
evaporating means,
at a time.
apparatus including a .re
means and a refrigerant
means for controlling, the
apparatus for normally maintaining the evaporat
3O ing means at a normal average temperature, a
means to normal operation.
14. Refrigerating apparatus including a refrig
temperature of the cooling unit by intermittently p. 0
operating the liquefying means to provide cycles
composed of an operating period and an idle pe—
riod so that the temperature of the evaporating
means is lowered to a predetermined normal low
temperature limit during one portion of the cycle
and raised to a normal predetermined high tem
perature limit during another portion of the
cycle, means operable at will for altering the op
eration of the control means to raise the average
temperature of the evaporating means for a pre
determined number of successive cycles for de
frosting purposes and thereafter returning the
refrigerating apparatus, including the control
means to normal operation.
15. Refrigerating apparatus including a re
frigerant liquefying means and a refrigerant
evaporating means, cyclical control means for
starting and stopping the refrigerant liquefying
means for maintaining said evaporating means at
freezing temperatures at which frost collects O
?rst means operable at will for temporarily in
thereon, and manually initiated defrosting means
creasing the'temperature of the evaporating‘ operable at will for temporarily increasing the
means to provide defrosting cycles and thereafter temperature of the evaporating means above ice
automatically returning the apparatus to normal freezing temperature for a plurality of successive
operation, a second means operable at will for
shutting off the apparatus, and selective com
mon means for selectively controlling the ?rst
means and the second means.
12. Refrigerating apparatus including a refrig
cycles to'melt frost from the evaporating means on Li
and thereafter automatically returning the appa
rating to normal operation.
16, Refrigerating apparatus including refriger
ratus for maintaining the evaporating means at
ant liquefying means and a refrigerant evaporat
ing means, means for controlling the apparatus
for maintaining the evaporating means at freez~
ing temperatures, means for automatically at
a normal average temperature, a ?rst means
predetermined intervals increasing the tempera
erant liquefying means and a refrigerant evapo
rating means, means 'for controlling the appa
operable at will for temporarily‘ increasing the
.45 temperature of the evaporating means to pro
vide defrosting cycles and thereafter automati
cally returning the apparatus to normal opera
ture of the evaporating means above freezing
temperatures for providing periodic defrosting
cycles, manually initiated means operable at will
for temporarily increasing the temperature of the
tion, a second mass operable at will for shutting evaporating means above ice freezing tempera
off the apparatus, a third means operable at will tures, and thereafter automatically returning the
50 for temporarily lowering the temperature of the apparatus to normal operation, said manually '
evaporating means for freezing purposes, and initiated means including means for rendering
common means for controlling the ?rst means, the periodic means inoperative for succeeding
the second means, and the third means.
cycles.
13. Refrigerating apparatus including a re
17. Refrigerating apparatus including a re
55 frigerant evaporating means and a refrigerant
frigerant liquefying‘ means and a refrigerant
liquefying means, control means for controlling evaporating means, pressure operated means for
the liquefying means to maintain a normal av
.erage temperature of the evaporating means by
intermittently operating the liquefying means to
provide cycles composed of an operating period
~ and an idle period so that the temperature of
the evaporating means is lowered to a predeter
' mined normal low temperature limit during one
portion of the cycle and raised to a normal pre
determined high temperature limit during an
other portion of the cycle, each being below the
freezing point, means operable at will for alter
ing the operation of the control means to raise
" the high temperature limit above the freezing
controlling the apparatus for normally maintain
ing the. evaporating means at a normal average
temperature, an abutment means, an engaging
means carried by said pressure operated means,
means for periodically bringing said engaging
means into alignment with the abutment means
to periodically vary the temperature of the
evaporating means, and means for holding said
engaging means out of alignment and prevent
ing the effective operation of the periodic means.
JOHN RALPH FEI-IR.
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