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Патент USA US2123073

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July 5, 1938.
\
c. w. BELL
'
2,123,073
MEANS FOR AUTOMATIC DEFROSTING OF REFRIGERATING ‘SYSTEMS
Filed April 50, 1932
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INVENTOR
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' ATTORNEYS
July 5, 1938.
‘ ‘
c. w. BELL '
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2,123,073
MEANS FOR AUTOMATIC nmmosnue 0F REFRIGERATING SYSTEMS
Filed‘ April 50, _19s2
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INVENTOR
Our/e5 W Bell.
ATTORNEYS
July 5, 1938.
c. w. BELL
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‘ 23235073
MEANS FOR AU'fOMATIC DEFROST'ING OF REFR-IGERATING SYSTEMS
Filed April 30, 1932
6 Sheets-Sheet 3
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‘INVENTOR
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Char/e5 W 56/!‘
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July5,1938-
‘
c.w. BELL
‘
-
2,123,013
MEANS‘FOR AUTOMATIC DEFROSTING OF‘REFRIGERATfNG SYSTEMS
Filed April 30, 17932 >
6 Sheets-Sheet 4
[bar/es W Bell. '
BY
.
m
ATTORNEYS
July 5, 1938.
‘
'
cfw. BELL
‘
2,123,073
MEANS‘ FOR AUTOMATIC DEFROSTING OF REFRIGERATING SYSTEMS
_
Filed April 50, ,1932
'
6 Sheets-Sheet 5
INVENTOR
Char/es W Bell
“M
‘ ATTORNEYS
July 5, 1938. >
c. w. BELL '
2,123,073
_
MEANS FOR AUTOMATIC DEFROSTING OF REFRIGERATING SYSTEMS
Filed Ap_ril'30, 1932
6 Sheets-Sheet 6
\“l.|'‘v
by21/l/
‘Al
mm
mm
INVENTOR
Char/es W Bell '
"MM
,
‘
'
4I7'0RNEYS'
Patented July 5, 1938
2,123,073
UNITED STATES PATENT OFF-ICE
2,123,073
‘
' MEANS FOR AUTOMATIC‘DEFROST'ING OF
REFRIGERATING SYSTEMS
Charles w. ‘Bell, Westfield, N. J.; Edythe H. Bell
‘
executrix of said Charles W. Bell, deceased
‘Application April 30, 1932, Serial No. 608,531 '
15 Claims.
(01.
62-4)
_
.
provision ofmeans, adapted for use in connec
ing elements of refrigerating units or systems tion with a system which automatically works
This invention relates to the defrosting of vecol
intermittentlylin accordance with the ‘require
and more particularly to means ‘for starting such
ments of the system, for testing the thickness of
the ice on the cooling element Just‘ before the 5
system starts up after each rest period and pre-'
ventingsuch starting if the ice is found to have
reached a predetermined maximum thickness.
Another object of the invention relates to pro
. defrosting automatically when the ice on the -
5 cooling element reaches a predetermined thick
' ness and for stopping the defrosting when the
ice is melted away to a predetermined thinness.
,In domestic and commercial refrigerating units
or systems wherein the temperature in a con?ned
10 space‘. such as the interior 'of an enclosed c'om- . vision, in connection with a system which auto- 10
matlcally works intermittently in ‘accordance .
partment, box or case, is maintained, at a‘ de?
nite point or within narrow limits adiacent with the requirements thereof, not only for test
thereto, there gradually accumulates on such ' ing the thickness of the ice on the cooling element
" cooling unit a coating of'ice‘or frost which, if ' just ‘before the system prepares to start up after
ll it buiids‘up to an excessive thickness, interferes each rest period and preventing such starting if 16
with or-prevents satisfactory and proper action vthe ice be found to have reacheda predetermined
of the cooling unit in maintaining efficiently the maximum thickness, but also for permitting such
desired predetermined temperature.
' starting when the ice has melted to a predeter
Particularly in domestic refrigerating systems,
20 the primary source of refrigerating effect, or the
‘
refrigerantesuppiying means, is intermittently
mineddegree of thinness.
'
'
Another object relates to the use of a feeler 20
movable toward and from the cooling element of
operated in accordance with the action ‘of a an intermittently operated -system,a control de
suitable control caused to operate, for example, vice for prevention or permitting the starting of
by variations of pressure within the system or the system, ‘and operating means for normally
actuating the feeler without operation of the 25
25 variations of thetemperature in the compart
mentor the space within which cooling is to be control device and for actuating the control de
vice when the feeler is stopped by ice of a pre
effected or of the cooling unit itself. Hereto
fore, irrespective of the‘particular nature of the determined maximum thickness on the cooling
control. defrosting has been effected by manually element, said operating means being restored to
30 stopping the operation of the refrigerant-supply-' normal operation upon completion of the defrost- 3o
.
ing means andleaving it in this condition until ing action. '
Further objects of the invention are to pro
the ice coating has melted either completely or '
‘ vide defrosting means of which a substantial part
g to a desired degree of thinness. The usual in
_ structionsare to effect the defrosting operation ‘is self-contained. and may readily be applied to
‘35 at regular fixed intervals but these intervals may any one of ‘the different types of intermittently 35
well be varied for the convmience of the‘ oper
ator and in view of the varying rates of growth
of the ice coating under various conditions.
An important object of the invention is to pro
’ 4o vide for automatic control of the defrosting op
eration in accordance ‘with changes of condition
in the refrigerating system‘ which may be con
sidered to include the cooling chamber as well
as the closed system "in which the refrigerant cir
45
‘
culates.
‘
>
‘
I
Another object of the invention is to provide,
' in connection with a refrigerating system auto-.
‘matically started and stopped in accordance with '
‘ refrigerating conditions, for ‘automatic starting
operated ‘machines. and to provide defrosting
means which will be substantially free from in
terference, such as by ice on the cooling element.‘
Preferably the defrosting control includes a
feeler movable toward and from a=cooling eie- 40
-ment on which the ‘ice collects, an operating or
motor element moving in accordance with
changes of conditions in the system, a device,
such as a switcher valve, for preventing or per
mitting operation of the refrigerant-supply 45
means, a device operable by the motor element
of ‘the control to‘ reciprocate the feeler or to
operate the switch device or valve device to pre
vent operation of the refrigerant-supply means,
and yielding means normally preventing opening 50
ing element reaches a predetermined maximum a of the switch device or closing of the valve de
vice (whichever be used) but yielding when the
thickness and automatic stopping of this oper
v50 of. a defrosting action when the ice on the‘cool-
ation when the ice reaches a predetermined de
gree of thinness.
.55
'
Another‘ object of the invention ‘relates to the
feeler is checked in its" forward movement by
‘ engagement with a predetermined thickness of ice
on the cooling unit and returning to normal po- 55
2
2, 128,073
sltion when the ice is melted to a predetermined
thinness and permits the feeler to advance to a
From the condenser the refrigerant passes to a
terposed between the motor element of the con
trol and the feeler and the shutoff device is
receiver or reserve reservoir l3 connected in a
adapted to operate either the feeler or the shut
off depending upon which offers the greater re
sistance. During ordinary operation the shut
frigerant to the cooling unit or evaporator I!
off device is yieldably held against operation thus
expansion valve (not shown)‘ and a ?oat operated
er which advances during rest or idle periods to a
position corresponding with the starting condi
tion of the main control and retracts during ac
tive periods of the refrigerant-supplying means.
When, however, the movement of the feeler is
prevented by engagement of the same with ice
of a predetermined maximum thickness on the
cooler the shutoff device is operated against such
yielding resistance and the defrosting operation
-20 is started. Then, as the. temperature rises and
other changes in condition occur, the condition
of the shuto? device is changed further so as to
delay the throwing out of the shutoff device.
When the ice has been melted to a predetermined
thinness and the feeler is advanced accordingly
farther than in its normal operating movement,
the shutoff deviceis thrown out of action.
Other objects and advantages will be apparent
upon consideration of the following description
30 and of the drawings, in which:
Fig. 1 is a diagrammatic view illustrating one
embodiment of the invention as applied to are
frigerating system of the compression-expansion
type in which intermittent action of the com
pressor and the action of the defrosting device
are controlled by variations of pressure in the
refrigerating system, the parts being shown in
the positions assumed just after starting the re
irigerating system for the ?rst time or at the end
40 of a defrosting operation;
Fig. 2 is a view similar to Fig. 1, but showing
the vparts in the positions assumed just before
the compressor is shut off by the main control,
the‘feeler being at the rearward end of its nor
45 mal operating path;
Fig. 3 is a view similar to Fig. 1, but showing
the parts in the positions assumed just after the
main control has started the compressor, the
feeler being at the forward end of its normal
50
refrigerant heated during compression is cooled.
corresponding position. Preferably the device in-.
10 causing normal operating movement of the feel
25
check valve II to a condenser l2 in which the
operating path;
suitable manner, as by conduit M, with a cooling
element or unit 15. Admission of the liquid re
may be controlled by suitable means such as an
valve (not shown). From the cooling element
or evaporator IS the expanded refrigerant is re
turned through a suitable conduit or pipe I6 to
the compressor into which it is drawn past a
check valve I'I designed to prevent return of the
15
refrigerant into the suction line l6.
Preferably, the compressor is driven by an
electric motor_l8 which may be coupled directly
to the compressor or indirectly as by means of
reduction gearing ‘(not shown). ‘As here dis
closed, the rotor of the motor is directly con 20
nected with a shaft [9 carrying a crank 20 which
is connected with the piston of the compressor
by means of a connecting rod 2|. Power for
actuating the motor I8‘ is provided through a
circuit 22 and intermittent action of the motor
may be obtained during ordinary operation by
25
means of a control 23 having a connection 24
with the receiver l3 and adapted to open the
circuit 22 when the pressure in the receiver l3
equals or exceeds a predetermined value and to 30
close the circuit 22 when the pressure in the
receiver l3 drops to‘ or below a predetermined
pressure. Preferably, the circuit 22 is also pro
vided with a hand switch 24a.
>
When the ice accumulates on the cooling ele 35
ment l5 up to a predetermined thickness, it be
comes necessary to defrost or remove ice from
the cooling element. Heretofore, defrosting has
been effected by manually shutting off the com
pressor and maintaining it in that condition until 40
the ice has melted to a predetermined thinness.
The present invention contemplates automatic
defrosting of the cooling ‘element, as by means
for opening and closing the circuit 22 independ
ently of the action of the control device 23. Such 45
opening and closing of the circuit may be effected
by a switch 25 including a ?xed contact 26 and a
movable-contact 2'I controlled by the automatic
defrosting means, which may include a motor or
actuating portion operated in accordance with
Fig. 4 is a view similar to Fig. 1, but showing
changes in pressure in the receiver I3, a feeler 28
the parts in the positions assumed after the
movable toward and from the cooling element IS,
auxiliary control has been operated, due to the a device for controlling the switch 25, and means
stopping of the feeler during its forward normal‘ interposed between the motor element on the one
55 operating stroke, to prevent starting of the com
hand and the feeler 28 and the switch operating 55
pressor;
device on the other hand, whereby the motor
Fig. 5 is a view corresponding to Fig. 1, but element normally acts to reciprocate the feeler
illustrating control of the intermittent‘ action of ‘but upon engagement of the feeler with ice of
the compressor and control of the defrosting de
excessive thickness on the cooling element acts to
60 vice in accordance with changes in temperature open the switch 21.
60
in the space cooled by the refrigerating system;
Preferably such interposed means includes a
Fig. 6 is a diagrammatic view illustrating one‘
embodiment of the present invention applied to a
refrigerating system of the absorption type, both
65 the intermittent action of the refrigerating sys
tem and the action of the defrosting means being
controlled in accordance with changes in tem
perature in the space to be cooled; and
Fig. 7 is a sectional view illustrating one form
of valve for control by the defrosting device for
shutting oil‘ the supply of gas to the burner of
the absorption system.
‘Referring to Fig. 1, l0 designates a compressor
from which a suitable refrigerant, such, for
75 example, as sulphur dioxide, is forced past the
closed system ?lled with substantially incom
pressible ?uid, preferably a liquid having a boil
ing point above the'maxi'mum and a freezing
point below the minimum temperature to which 65
the device will be subjected in operation, and is
provided with a Sylphon 29 for operating the
feeler 28, a Sylphon 30 for» controlling the switch
25, and an actuating Sylphon 3| controlled by
‘the motor element. Obviously, contraction of the 70
Sylphon 3| will cause expansion of one or both
of the Sylphons 29 and 30, and expansion of the
Sylphon 3| will cause contraction of one or both
of the Sylphons 29 and 30. It will be understood
that one end of each of the Sylphons 29, 30 and 75
3
2,128,073
3| is normally held in ?xed position and that the
element ii.‘ If the ice on the cooling element
other end is in each case left free for movement
had not reached the predetermined thickness‘
with respect to the fixed. end.‘ The feeler 28 is
connected with the free end of the Sylphon 23
the feeler would merely advance to the forward
end of that movement determined by the low
pressure at which the main control acts to start
and preferably consists‘ of a plate or disc 32 to'
engage the ice and a rod 33 extending axially
with respect to the disc 32 to the free end of said
Sylphon 29 to which it is secured so as to extend
of its normal movement without striking the
perpendicularly therefrom. Preferably the plate
ice on the cooling element there is no need for .
the compressor l8.
‘
When the feeler 'is thus advanced to the end
10 32 and also the rod 33 are composed of material - defrosting and the switch 25 remains closed. 10
having a low thermal conductivity, for example,
hard rubber or ?bre.
" '
,
-
_
The pressure in the receiver and, its connection
to the control 23 falls until this control is oper
' The Sylphon‘ 29 may be supported at its inner ated to start the compressor ill, the action of end on a bracket 34 adjustably mounted on ‘a which continues" until the pressure in the re-'
ceiver i3 reaches the‘ predetermined. degree 15
?xed support 35 by means of a bolt or screw
projecting through a slot 31 in the baseof the whereupon the control 23 is again operated to
bracket. This enables the Sylphon 29 to be ad~' stop the motor l8. During this building up
justed toward and from the cooling element l5 1 of pressurevthe feeler 28 has been retracted to
to adjust the position of the feeler with relation its rearward position determined by a spring 62
interposed between the bracket 52 and the free 20'
20 thereto. 'The'inner end of the Sylphon 38 may
be mounted on a bracket 38 ?xedly secured on . end of the Sylphon .48. This spring may be of
a support 39, the outer end‘ of the Sylphon 38
having ?xed thereto the movable member2‘l of
the switch 25'which is‘ normally kept closed by
such strength and characteristics as to provide
for a range of movement of the Sylphon 48
requisite‘ for the proper operation thereof under
yielding pressure exerted on the outer. head or ' variations of pressure to which it is subjected in
end of the Sylphon 38, as bymeans of a spring
40 of suitable strength interposed between the
outer end of said Sylphon 38 and a ?xed member
operation.
'
'
This spring 62 also assists in contracting or
collapsing the Sylphon 48 when the pressure in
such as a- bracket 4| secured in ?xed position ‘ the. receiver falls and‘ helps to overcome the
30 on the support 39. The inner end of the Sylphon
3| may alsobe supported by a ?xed bracket 42
preferably ?xed on a ?xed support 43.
‘The closed ‘system containing the Sylphons 29,
30 and 3| may also include a pressure conduit
or pipe 44 connecting Sylphons 29 and 3| and
spring 48 and the resistance of the Sylphon 30
and open the switch 25 when the feeler 28 en
gages ice of the predetermined maximum thick-> . ness on the cooling element l5.
The operation of the apparatus is substan
tially as follows: During operation of the com- :
a conduit 45 connecting conduit 44 with Sylphon pressor, pressure is built up in the receiver l3
30. It will be ‘evident there must be some ?exi . until it reaches the predetermined maximum
at whichthe main control 23 acts to open the
' bility between Sylphons 29 and 3| to enable ad
justment of bracket 34 while bracket 42 remains circuit 22 and stop the motor l8 and the com- .
stationary. This ?exibility may be obtained in pressor l8. Then the pressure in the receiver i3 40
‘various ways-{or example, by providing conduit gradually drops as the liquid passes therefrom
44 with an expansion coil or loop 46 which-also to the cooling unit l5 until the pressure reaches
prevents interference with pipe or conduit 45.
In carrying out the present invention, the ar
. rangement should be such that the feeler 28
would be advanced as the system approaches a
condition for again starting the compressor and
retracted as a result of such restarting, and that
upon contact of the feeler during ‘its forward
‘ movement with ice of excessive thickness the_
the predetermined point atv which the main con
trol 23 is set to restart the motor and, the com
pressor. The Sylphon 48, is, of course, sub 45
jected to the same internal pressure as the re
ceiver i3 and expands against the action of the
spring 52 as the pressure increases and contracts
‘when the pressure falls. This Sylphon 48 is so
constructed and designed and the spring 62 is of v
auxiliary control_'or switch 25 would be oper
ated Just before the system reaches the condi- tion to cause action by the control 23 to start,
' up the compressor. If the defrosting is to be
controlled by pressure conditions, the feeler, 32
should be advanced as the pressure decreases in
the pressure or high side of the system. ‘This
-_ may be done by connecting the pressure line 24
by a branch 41 with the adjacent end of a Syl
phon 48, which end is carried on a bracket 49
such strength or so adjusted that the Sylphon
will be at its maximum desired expansion when
subjected to- the maximum pressure in the re
ceiver. Due to the connection between Sylphon _
48 and Sylphon 3|, the latter will beat its maxi
mum desired expansion at the‘ same time as Syl
phon 48 and at the same time theSylphons '29
and 38-wiil be in their condition of maximum
contraction, causing-the feeler 28 tube-at its
maximum distance from the cooling element l5, 60
' ?xedly mounted on the ?xed support 58.
and movable contact 21 will be in engagement _
with fixed contact 28 at the switch 25. (See
For‘
connection with the Sylphon 3 I, the other end of.
'this Sylphon may be provided with a rod‘ 5|
guided in- a bracket 52 secured to a ?xed’ sup
65 port 53 and pivotally connected ‘with one end
Fig. 2.)
'
Following the stopping of the motor l8 by the »
‘main control 23, the pressure in the receiver falls,
‘of a lever 54 centrally pivoted at 55 andpivotally
, causing contraction of the Sylphons 48 and 3| and ,
connected at its other. end with a rod 58 at‘
tached to the free and outer end of the Syl
tending to expand the Sylphons 29 and 30. Ex
pansion of the Sylphon 38, however, is resisted
by the spring 48 so that the only expansion is that
phon- 3|.
.
‘It will be evident that, with this arrangement, ' of Sylphon 29 and the feeler 28 is advanced to 70
' 7.0
ward the cooling element I5. Thus, if advance
a drop in pressure in the receiver l3 and con
nection 24 will tend to contract the Sylphon 43 of the feeler 28' is not opposed during the con
and through the lever 54 compress the Sylphon traction of Sylphon 43 caused by the drop in
3|.‘ This would ordinarily expand the Sylphon ' pressure to the‘ point at which the main control
75 28 and advance the feeler 28' toward the cooling 23 restarts the compressor, contacts‘ 26 and 2i 75
4
2,123,073
will remain in engagement with each other and
the control 23 will restart the motor and the
caused to operate to produce defrosting or melt
ing of the coating. Furthermore, as soon as the
compressor in the usual manner, thus serving to
ice has been melted to the predetermined degree ,
retract the feeler 28 from the forwardend of its
normal operating path. This intermittent oper
of thinness (Fig. 1)- the compressor H3 is started
and immediately acts to increase the pressure in
the receiver l3 and withdraw the disc from the
cooling element l5 before any substantial effect
to freeze it fast to the cooler can be produced by
ation of the compressor will continue until the
ice 63 on the cooling unit reaches the predeter
mined maximum thickness (Fig. 4) to operate the
defrosting means.
10
‘
The Sylphon 29 is so positioned by adjustment‘
of the bracket 34 that, when the pressure in the
receiver i3 has fallen to the point where the main
system control 23 would normally start the com
pressor, the corresponding condition of expan
15 sion of the Sylphon 29 would cause positioning of
the disc 32 of the feeler 28 at such a distance
from the cooling element l5 as to cause the disc to
strike the ice coating 62, if the ice be of the maxi
mum thickness desired, somewhat before the con
20 dition for starting the compressor is reached.
Then since further movement of the feeler and
expansion of the Sylphon 29 are prevented before
the refrigerating or freezing action which is re
sumed as soon as the compressor starts.
10
' During the defrosting operation the water re
sulting from the melting of the ice coating on the
cooling element l5 will drip therefrom. Obvi
ously, it will be necessary to arrange for the dis
posal of this drainage water as, for example, by
the use of a drip pan “normally supported under
the cooling element and removable for emptying.
While the motor element of the defrosting de
vice which has just been described is actuated by
the variation in pressure in that part of the
refrigerating system which is on the discharge
side of the compressor, commonly known as the
“high side" of the system, it will be understood
that the motor element may be actuated by the
variation in pressure in that part of the refriger 25
the normal contraction of Sylphons 48 and 3] is
completed, the further contraction of these Syl
25 phons will cause the expansion of Sylphon 30
against the action of spring 40 and opening switch . ating system which is on the suction side of the
25, thus preventing starting of the motor by the compressor, commonly known as the “low side"
main control 23.
or “suction side" of the system. It will be under
The fall of pressure in the receiver It will con
30 tinue until the pressure throughout the main
refrigerating system is equalized.
This fall in
pressure will tend to cause further contraction
of Sylphons 48 and 3| and further expansion of
Sylphon 30 until contraction of Sylphon 48 is
35 checked by engagement of the hooked lug 51 on
stood that in such case the device is so arranged
that an increase of pressure in the “low side” of 30
the refrigerating system will move feeler toward
the cooling unit and a decrease in pressure in the
refrigerating system will withdraw feeler from '
cooling unit. In other words, Sylphon 48 will be
so connected to Sylphon 3| as to cause contrac
the free end thereof with the adjustable bracket tion of Sylphon '3l when Sylphon 48 expands and
or stop 58 which is so adjusted that the feeler disc to cause expansion of Sylphon 3| when Sylphon
32 will have advanced to a point short of that 48 contracts, and stop 58 and hook 51 will be so
corresponding with the minimum thinness (Fig. 7 arranged as to limit or stop the expansion of
40 1) of the ice coating for defrosting suiiicient
Sylphon 48 at any desired point.
_ 40
to permit the Sylphon 30 in) contract under the
The motor element of the defrosting device or
in?uence of the spring 40 to bring the contact 21 control may be of a thermostatic type and pref
into engagement with the contact 28, thus closing erably devices of this type are used in connec
the switch 25 and restoring the motor I 8 to the tion with refrigerating systems in which the main
control‘ of the main control 23. It will be seen control is thermostatic. In Fig. 5 there is shown
that during the defrosting operation the disc 32 an illustrative embodiment of a defrosting device
of the feeler 28 will continue to be pressed against thermostatically'controlled and applied to a sys
the surface of the ice coating and will advance tem similar ingeneral to that shown in Fig. 1
as such surface recedes, due to the pressure ex
but having a main control 23a of the thermo
50 erted by the spring 40, until the Sylphon 30. static type effective to open the motor circuit
reaches its full allowable degree of contraction _ when the temperature in the compartment to be
and causes closing of the switch 25.
. cooled or of the cooling unit itself drops to a
It should be noted that the Sylphon 30 with the predetermined minimum and to close the motor
spring 40 cooperating therewith has three func
circuit when the temperature rises to a prede
tions: (1) to open and close the switch 25; (2) .to termined'maximum. The only feature by which
supply the pressure to expand the Sylphon 29
and advance the feeler 28 after Sylphons 48 and
3| have reached their maximum degree of con
traction; and (3) to limit the maximum possible
60 pressure in the closed system containing the Syl~
phons29, 30 and 3|. This limitation of pressure
is necessary in view of the fact that ice will melt
under heavy pressure and excessive pressure of
‘ the disc 32 against the coating of ice on the cool
65 ing element would cause faster melting of the ice
opposite the feeler than at other points thus caus
ing the restarting of the compressor ‘before the
cooling element is suitably defrosted.
'
It should also be noted that the disc 32 of the
feeler 28 cannot be frozen to the surface of the ice
coating on the cooling element and thus interfere
with proper operation, in that the disc does not
come into contact with the surface of the ice
coating during normal operation and, when it
does engage the ice, the defrosting device is
the defrosting device of Fig. 5 diiIers substan
tially from that of Fig. 1 resides in the inclusion
of a thermostatic device in the means for con
trolling the Sylphon 3| and the omission of any
control by variations of pressure in the receiver. 60
The thermostatic device disclosed for purposes
of illustration is in the form of a bimetallic strip
65 secured at one end to a fixed member“; and
pivotally connected at its other end with a con-.
necting rod or link 61 which is' pivotally con
nected'with a member or rod 56a secured to the
free end of the Sylphon 3| and positioned sub
stantially axially with respect thereto. In order
to limit the contraction of the Sylphon 3i and
the advance of the feeler 22, the rod 56a may be '
provided'with a'transversely projecting lug 51a
adapted to limit the contraction of the Sylphon
3! by engagement with an adJustable bracket or
stop Ila secured on the ?xed member 43 by means
of a bolt or screw 88 passing through a slot 69 75
2,128,078
.
.
,
5
in the base of the bracket. in order to avoid ex- ' the generator through va pipe 82 which forms the
cessive stresses and possible breakage when the inner tube of a double tube 83 through the outer
bimetallic strip 85 tends to advance the rod fur-‘ - part of which passes in the opposite direction
ther than the position determined by the ad
justable stop 58a, suitable provision for yielding
10
weak liquor received from a.pipe 84 connected
with a higher point of the generator and ‘dis
is made in the train of connections, as by con
charged throughva pipe 85 extending upwardly
necting the, adjacent end of the connecting rod
61 with the rod 56a by pivotally connecting the
in the water [jacket of the absorber to the upper _
part ofthe absorber proper. The cooling water
former with a block ‘l0, mounted to slide in a slot
is supplied through a pipe 86 which communi
in the end of the rod and normally held at the.
cates with the lower part vof the water jacket of
outer end of the slot byvmeans of a helical spring
12 interposed between the block and the other
end of the slot. The operation is substantially
the same as described in connection with the ap
paratus sl'iown inlFig. 1.
.
the absorber and passes from this water jacket
to the outer tube of the condenser 80 from which
In-Fig. 6, there is illustrated an application of
a thermostatically controlled defrosting device
to an absorption system. The defrosting device
may be of any suitable form but for convenience
20 is illustrated as being the same as that disclosed
in Fig. 5 except that it-is utilized to control the
supply of gas to a burner of an- absorption sys
‘tem which may be of ‘any suitable form but for
convenienceds illustrated as being of Munsters
Platen type shown'and described on pages 252
to 258, inclusive of “The Handbook of Refriger
it is discharged through a pipe 81.
The ?ow of gas to the burner 19 may be shut
off automatically‘by a' main thermal control 86 15
associated with the gas supply line 81, when the
temperature drops too low, and turned on auto
matically when the temperature rises to a pre
determined degree, the relighting of .the burner
being, effected by means of a pilot light 88. The 20
‘ defrosting ‘device is just the same as that shown
in Fig. 2 except that“ the Sylphon 30 acts through
a member Z'Iasecured to the free end thereof
to close a quick-acting valve 89 when the ice on
the cooling element or evaporator 15 reaches a 25
‘predetermined thickness, and to open the valve
ating Engineering" by W. R. Woolrich, published ' when the ice is melted to a predetermined thin
by D. Van Nostrand Company, Inc., New York,
N. Y., 1929. The absorption system here shown
30 includes an evaporator .15, an absorber 16 having
a wateriacket, and a connection 11 between the
upper part of the absorber and the upper part of
theevaporator. At the time of manufacture of
‘the apparatus, hydrogen at a suitable pressure,
150 pounds absolute for example, is sealed in the
system and occupies the upper part of the evapo
ness.
‘
-
.
.
As shown in Fig. '7, the valve 89 maytake the
‘form of a flat casing to which sections of the 30
pipe or line 81 are connected at the opposite ?at
faces and the opening or closing of the valve may
be effected by means of a member 9!! inside the
casing at ‘the discharge side thereof and proq
vided with an opening 9| which'registers with 35
the outlet opening of the casing when the member
- rator, the upper .part of the absorber and the
or slide is held in its raised position by a mem
connectingpiping or connection 11.- Therefrig
her. or link 92 passing through the upper part of
the casing and pivotally connected with the mem
erant used is ammonia originally in the form of
40 aqua ammonia located between the inner and ‘ ber 21a. When the Sylphon 30 is expanded due 40
outer walls of an annular tubular generator 18 to engagement of the feeler with ice of a maxi
- which may be heated by a gas burner 19 at the mum thickness on the cooling element or evapo
vrator 15, the slide 90 will be lowered su?lciently
thereof.
‘
When the-aqua ammonia is boiled in the gen > to close the outlet of the casing of the valve 89.
The slide 90 may be kept in close engagement 45
45 erator, ammonia gas is given oil and the original
150 pounds of hydrogen pressure is increased by with the outlet face of the casing by suitable
say 20 pounds absolute, thus making the total means such as a bow spring 93 having one end
fastened to the opposite side of the casing andv
pressure 170 pounds absolute. ‘ In this boiling
_ bottom
‘ ' there are formed ‘ammonia gas bubbles which
50
the other end free but resting against the same
side of the casing. It should be understood that 50
carry globules of rich liquor up vthe thermo
Sylphon tube "a to the top of the_generator._ the spring 93 does not cover theopening 9i in
The ammonia gas from the generator is passed the slide 90 when the latteris in its Fig. 7 posi
through a rectifier (not shown) where some cool
ing takes place, the liquid aqua ammonia sep
arating out and draining back to the generator
and the ‘dry ammonia gas passing through a
condenser 80' which may be of the double tube
' tion but is at one side of the opening.
. It may be desirable to maintain the normal
operation of the refrigerating system under con 55
ditions which would otherwise result in defrost
ing. Such maintaining of the normal operation
type with coolingwater'passing between the two'
may be obtained by-suitable means such as a
tubes. Theammonia thus condensed flows from ‘ manually, operated switch ‘94 in shunt or parallel
'60 the condenser into the evaporator "where it
vaporizes justfast enough to nearly balance the
65
with the switch 25 in the electric refrigerating
systems shown in Figs. 1 to 5, inclusive. This
switch would, of course, be open undervordinary
pressures in the generator and the evaporator,
in that too rapid evaporation will raise the pres ‘ circumstances but would be closed when it was
sure in the evaporator ‘I5 and prevent the flow of desired to assure continuance of the usual refrig
crating action without defrosting. It will be 65
ammonia to the same.
As the ‘condensed ammonia evaporates in said evident that switch 240. provides for throwing
evaporator, it diffuses with the hydrogen there the whole system ‘out of operation‘ or for start
present and'the' diffused gas being heavier than
hydrogen will fall to the bottom of the evaporator
70 and pass therefrom through a pipe M to the
bottom of the absorber ‘I8 which is .at a lower
level. The ammonia here combines with weak
liquor entering the absorber thus releasing hy
drogen which goes to thetop of the absorber
75 and forming strong liquorwhich passes back to
ing it.
In the absorption system shown in Fig.6 main
tenance of normal operation may be assured, 70
regardless of conditions which would ordinarily
cause defrosting by providing a by-pass around
the defrosting-control valve 89 and a valve 95
to control the by-pass. When valve 95 is open,
the defrosting unit cannot produce defrosting.
6
2,123,073
This system may also be provided with a' valve comes into engagement with a layer of ice of pre
96 in the fuel line 81 adapted, when closed, to determined thickness on the cooling element and
permit operation of the auxiliary control but to
shut down the entire system.
return the parts to normal position upon melting
It should be understood that the present ‘in
of the ice to a predetermined thinness and the in
CH vention is applicable to refrigerating systems of
resulting forward movement of the feeler.
other types than those disclosed and that, al
3. The combination with a refrigerating system
though it is desirable'to use a pressure-operated
motor element for a defrosting device used with
a refrigerating system controlled in accordance
10 with pressure therein and to use a thermostatic
motor element when the main control is ther
mostatic,'it is not necessary to do so.
'
including a compressor, a condenser, and a cool- .
ing element to which the condensed refrigerant
is supplied, compressor-actuating means and a
pressure-operated main ‘control for said com
pressor-actuating means connected by a pressure
The foregoing detailed description has been line with the refrigerating system of an auxiliary
given for clearness-of understanding and no control for preventing or permitting operation of
undue limitation should be deduced therefrom, the compressor-actuating means, a feeler movable
but the appended claims should be construed as toward and from said cooling element, a closed
system containing a suitable liquid and including
broadly as possible in view of the prior art.
Having thus described my invention, I claim: three Sylphons ?xed at their connected inner
1. The combination with a refrigerating system ends and having their outer ends movable to per
mit expansion or contraction, saidSylphons in
including a cooling element, means for supply
cluding one connected with the auxiliary control
ing refrigerant to said cooling element in condi
tion to cool the same and controlling means for
starting and stopping the operation of the re
frigerant-supplying means in accordance with
25 changes of condition in connection with said sys—
tem, of defrosting means including an auxiliary
control for preventing or permitting operation of
the refrigerant-supplying means, a closed system
to operate the same, a second one connected with
the feeler to operate the same and a third or
actuating Sylphon operated to expand and con
tract the others, pressure means connected with 25
said pressure line for contracting and expanding
said actuating Sylphon in accordance with
changes of pressure in said pressure line, and
containing a suitable fluid and having at one ' yielding means normally preventing expansion of
30
30 point a movable part adapted to exert pressure the auxiliary-control-operating Sylphon.
in the closed system, a second movable part
movable toward or from the cooling element in
accordance with increase or decrease of pres
sure exerted by movement of the first movable
35 part and a third movable part movable outwardly
and inwardly in accordance with increase or de
crease of pressure exerted by movement vof the
first movable part, a feeler connected with the
second movable member, a connection between
4. The combination with a refrigerating system
including a compressor, a condenser, and a cool,
ing element to which the condensed refrigerant
is supplied, compressor-actuating means and a
pressure-operated main control for said com
pressor-actuating means connected by a pressure
line with the refrigerating system, of an auxiliary
control for preventing or permitting operation of
the compressor-actuating means, a'feeler mov
40 the third movable part and the auxiliary control,
and yielding means tending to prevent move
able toward and from said cooling element, a 40
closed system containing a suitable liquid and in—
ment of the third movable part but movable upon
engagement ‘of the feeler with ice of excessive
thickness on the cooling element to prevent oper
ation of the refrigerant-supplying means, and
acting upon melting of the ice to a predetermined
thinness to restore the refrigerant-supplying
their connected inner' ends and having their outer
ends movable to permit expansion or contraction,
said Sylphons including one connected with the 45
auxiliary control to operate the same, a second
cluding three interconnected Sylphons ?xed at
one connected with the feeler to operate the same
and a third or actuating Sylphonoperated to ex
2. The combination with a refrigerating system ' pand and contract the others, yielding means nor
including a cooling element, means for supplying - mally preventing expansion of the auxiliary-con 50
means to the control of said controlling means.
refrigerant to said cooling system in condition
to cool the same and controlling means for start
ing and stopping the operation of the refrigerant
suppiying means in accordance with changes of
condition in connection with said system, of de
frosting means including an auxiliary control
'for preventing or permitting operation of the
refrigerant-supplying means, a closed system
filled with a suitable liquid and including three
60 interconnected Sylphons with their inner ends
held in fixed positions, a feeler connected with
the outer end oi’ one'of said Sylphons for move
ment thereby toward and from the cooling ele
trol-operating Sylphon, and means for expanding
and contracting said actuating Sylphon in ac—
cordance with change of pressure in said pressure
line including a fourth Sylphon connected at its
inner ?xed end-with said pressure line and con 55
nections between the outer end of the fourth
Sylphon and the outer end of the actuating Syl
phon whereby they act in unison.
5. The combination with a refrigerating system
‘including a compressor, a condenser, and a cool
60
ing element to which the condensed refrigerant
is supplied, compressor-actuating means and a
pressure-operated. main control for said com
ment, means connected with the outer end of ' pressor-actuating means connected ‘by a pres
one of the other Sylphons for moving such end sure line with the refrigerating system between 65
the condenser and the cooling element, of an
inwardly when a condition requiring fresh re
frigerant in the cooling element is approached auxiliary control for preventing or permitting
and outwardly after such. fresh refrigerant has operation of the compressor-actuating means, a
been supplied, a connection between the outer feeler movable toward and from said cooling ele
ment, a closed system containing a suitable liq 70
70 end of the third Sylphon and the auxiliary con
trol to operate the same to prevent action of uid and including three interconnected Sylphons
the refrigerant-supplying means when said third fixed at their connected inner ends and having
their outer ends movable to permit expansion or
Sylphon is expanded, and yielding means nor
mally preventing expansion of the third Sylphon contraction, said Sylphons including one con
but adapted to be overcome when the feeler nected with the auxiliary control to operate the 75
2,123,073
7
same,ra second one connected with the feeler to ' supplied, ‘compressor-actuating means and a
‘ operate the same and a third or actuating Sylphon thermostatic main‘ control for said compressor-'
_ operated to expand and contract the others, yield
actuating means, of an auxiliary control for pre
.ing means normally preventing expansion of the
auxiliary-control-operating Sylphon,means for op
_ crating said actuating Sylphon in accordance with
rise or- fall of pressure in said pressure line in?
cluding a fourth Sylphon connectedv at its inner
?xed end with said pressure line,'connections
‘ between the outer end of the fourth Sylphon and
venting or permitting operation of the com
pressor-actuating means, a feeler movable toward In
and from said cooling element. a closed system
containing a suitable liquid and including three
interconnected Sylphons'?xed at their connected
inner ends and having their’outer' ends movable
to permit expansion or contraction, said Sylphons 10
including one connected with the feeler to oper
the outer end of the actuating Sylphon whereby
they act in unison, and yielding means resisting - ate the same and a third or actuating Sylphon
the expansion of the fourth Sylphon, thereby
tending to limit the rearward movement of the
operated to expand and contract the others, yield
ing means normally preventing expansion of the
feeler and to assist in advancing the feeler and ‘ auxiliary-control-operating Sylphon, means for
expanding and contracting said actuating
operating the auxiliary control.
6. The combination with a refrigerating sys
tem including a compressorya condenser, and
Sylphon'including a thermostatic device and a
connection between said thermostatic deviceand
a cooling element to which the condensed re , the outer end of the actuating Sylphon’, said con
frigerant is supplied, compressor-actuating means ‘ nection being strong enough to expand and col
and a pressure-operated main control for said‘ lapse said actuating Sylphon but yieldable to pre
20
vent damage when contraction of such Sylphon is
blocked, and a stop device to check the collapse
of the actuating Sylphon, thereby causing said
connection to yield.
9. The combination with a refrigerating system
movable toward and from said cooling element, a
of the absorption type including a cooling ele
closed system containing a suitable liquid and in
cluding three interconnected Sylphons ?xed at ment, a generator, ‘a burner, a fuel supply line for
their connected inner ends and having their outer said burner, a main control of the thermostatic
ends movable to permit ‘expansion or contraction, type for opening and shutting the supply line in 30
said Sylphons including one connected with the accordance with the demands of the system, and a
auxiliary‘ control to operate the same, a second pilot connected with said supply line at the en
one connected with the feeler to operate the same - trance side of the main control, of an auxiliary
and a third or actuating Sylphon operated to control in said supply line for closing and open
expand and contract the others,‘yielding means ing the supply line thereby preventing or permit
ting heating of said generator, a feeler movable
normally preventing expansion of the auxiliary
' compressor-actuating means connected by a. pres
sure line with the refrigerating system,'of an aux
iliary control for preventing or permitting opera
ation of the compressor-actuating means, a feeler
control-operating Sylphon, means for varying the toward and from said cooling element, ‘a closed
capacity of said actuating Sylphon with rise and system containing a suitable liquid and'including
fall of pressure in said pressure line including a , threeinterconnected Sylphons-fixed at their con
fourth Sylphon connected at its inner ?xed’end
'with said pressure line, yielding means resisting
the expansion ofsaid fourth Sylphon, connections
between‘ the outer end of said fourth Sylphon
and the, outer end of said actuating Sylphon to
cause them to act in unison, and means'for limit
‘ ing the movement of said fourth Sylphon to limit
contraction of the third Sylphon.
7. The combination with a refrigerating system
including a compressor, a condenser, and a cool
nected inner ends and having movable cuter ends
to permit expansion or- contraction, one of said
Sylphons being connected with the auxiliary con
trol, a ‘second one being connected with the feeler
to operate the same, the third or actuating
Sylphon being operated to‘ expand or contract 45
the others, yielding means normally preventing
expansion of the auxiliary-control-operating
Sylphon, means for expanding and contracting
said actuating Sylphon including a thermostatic
device and a connection between said thermo so I
static device and the outer end of the actuating
Sylphon, said connection ‘serving to actuate the
feeler or the auxiliary control when the feeleris
blocked and yielding when contraction of the
CI in! pressor-actuating means, a feeler movable toward - actuating Sylphon is ‘prevented, and a stop de 55
and from said cooling element, a closed system vice to limit the collapse of the actuating Sylphon.
ing element to which the condensed refrigerant
is supplied, compressor-actuating means and a
thermostatic main control for said compressor
actuating means, of an auxiliary control for pre
venting or permitting operation of ‘the com
10. The combination with a refrigerating sys
tem including a compressor, 'an electric motor for
operating said compressor, a circuit to supply
power to said motor, a condenser, a cooling ele 60
including one connected with the auxiliary con
ment, and a pressure-operated main control con
trol to operate the same, a second one connected nected with the interior of the refrigerating sys
with the feeler to operate the same ‘and a third tem and adapted to open said circuit and close said .
or actuatingv Sylphon operated to expand and‘ circuit when the pressure reaches predetermined
contract the others, yielding means normally limits, of an auxiliary control for the compressor
preventing expansion of the auxiliary-control- ’ actuating means including a second-switch in said
operating Sylphon, means for expanding and con
circuit, a feeler, means controlled by the pressure
in said system during normal operation for mov
' tracting said actuating Sylphon including a ther
mostatic, device,' and a connection between said ing the feeler toward said cooling element while
thermostatic device and the outer end of the the compressor is idle and from‘ said cooling ele 70
‘ actuating Sylphon, and means for limiting the ment when the compressor is working, and for
opening and closing said second-switch at other
contraction of the actuating Sylphon.
I ‘ '
' 8. The combination with a refrigerating system times, yielding means tending to hold said switch
including a compressor, a condenser, and a cooling closed, and a manually controlled switch in par
element to which the condensed refrigerant is allel with said second-switch.
75
, containing a suitable liquid and including ‘three
interconnected Sylphons ?xed at their connected
inner ends and having their outer ends movable
60 to permit expansion or contraction, said Sylphons
'8
2,123,673
1
‘tem including a compressor, an electric motor for
normal operating stroke, and manually con
trolled means i’or supplying fuelpast said aux
operating said compressor, a circuit tov supply
iliary control.
power to said motor, a condenser, a cooling ele
ment, and a thermostatic main control adapted
to open said circuit and close said circuit when the
13. In defrosting apparatus for a refrigerating
system embodying a cooling element, the combi 5
nationv of a pressure motor device, a feeler opera
tively associated therewith and having a predeter
mined normal range ofmovement, a refrigeration
control device and means, operable upon checking
11. The combination with a refrigerating sys
temperature reaches predetermined limits, of an
auxiliary control for the compressor-actuating
means including a second-switch in said circuit, a
feeler, thermostatic means for moving, during
normal operation of the refrigerating system, the
feeler toward said cooling element while the com
pressor is idle and from said cooling element when
the compressor is working, and 'for opening and
closing said second-switch at other times, yield
ing means tending to hold said switch closed, and
a manually controlled switch in parallel with said
second-switch.
‘
I
12. The combination with a refrigerating sys
tem of the absorption type including a cooling ele
ment, a’condenser from which refrigerant is sup
plied to said cooling element, a generator, a
burner, a fuel supply line for said burner, a ther
mostatic main control for opening and closing the
supply line in accordance with the demands of
‘ the system, and a pilot light connected with said
supply line at the entrance side of the main con
trol, of an auxiliary control in said supply line, a
feeler, means for moving the feeler towards said
30 cooling element when the temperature thereof is
falling and from the cooling element when the
temperature is rising or for opening and closing
a
of the feeler short of its normal range of move 1O
ment, to actuate said control device.
14_. In defrosting apparatus i’or a refrigerating
system embodying a cooling element, the combi
nation of a thermostatic motor ‘device, a feeler
operatively associated therewith and having a
predetermined normal range of movement, a re
frigeration control .device and means, operable
upon checking of the feeler short of its normal
range of movement, to actuate said control device.
15. In defrosting apparatus for refrigerating
systems, the combination of a reciprocating feeler,
an electric circuit control device, a closed system
containing a suitable liquid and including three
interconnected Sylphons normally ?xed at their
connected ends and having their opposite ends
movable to permit expansion or contraction, said
Sylphons including one connected with the con
trol device to operate the same, a second one con
nected with the feeler to operate the same, and a
third or motor Sylphon operated to expand and 30
contract the others, and yielding means normally
said auxiliary control, yielding meansnormally
holding the auxiliary control against closing but
preventing expansion of the control-device-oper
ating Sylphon but permitting such expansion upon
interference with the movement of the feeler du
permitting it to close when the feeler is stopped by
to the accumulation of ice.
ice on the cooler before it reaches the end of its
CHARLES W. BELL.
-
35
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