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Dec. 10, 1946. _
Filed Aug. 50, 1944
3 sheetséshee’c l "
m4! 4%BY
Dec. 10, 1946.
Filed Aug. 50, 1.944
3 Sheets-Sheet 2
FIG. 2:
KM Mia/1m
,éém: 2/
Deé. 10, 1946.
'K. M. GERTEls
Filed Aug. 30, 1944
s Sheets-‘Sheet 3
Patented Dec. 10, 1946
Karl M. Gerteis, Syracuse, N. Y., assignor to Car
rier ‘Corporation, Syracuse, N. Y., a corporation
of Delaware
Application August 30, 1944,‘Serial No. 551,957
7 Claims.
(Cl. 230-24)
This invention relates to reciprocating com
.pressors and more particularly to. methods of
and means for varying the effective displace
ment of a compressor responsive to variations in
positioning of applicant’s control so that the
compressor with respect to those cylinders to
. load requirements.
which the control is applied, starts completely
The .general object of 'theinvention is to pro
.vide for variably controlling theopeningwof one
.or more suction valves undercontrol of 1a regu
lating device re?ecting changes in load condi~
These and other features will be more apparent
‘from the following description of a typical ‘form
of the invention, a-ppliedto .a refrigerantcom
pressor, to be read in connection with the accom
panying drawingsin which
'. 4
In employing compressors, more particularly,
Fig. a diagrammatic view.of;a.refrigerat
ing machine having a plurality of cylinders-ap
refrigerant compressorsit is highly desirable to
plicant’s modulating .control being shown ap
regulate capacity in order-to obtain required re
plied to oneof the cylinders, althougniin lprac
frigeration effect withminimum loss of emciency.
tice,.it may be applied to severalofithem.
Various attempts have been made to achieve 15
Fig. 2 is a diagrammatic rview,.showing .the
modulating control of capacity, as by retaining
regulating means for ‘variously controlling vthe
open suction valves, and by other means which
timezand duration of .openingof a suction valve
maintain valves in fully opened or closed po
on one .cylinderofa compressor.
Fig. 3 shows'a detail view of a valve, actuated
Applicant provides a moree?ective solution
by suction pressure, employed'for regulating the
by modulating the capacity of acompressor by
unloading action; and
regulating the graduated closing of one or more
Fig.4 shows a. control arrangement‘ for regu
valves to re?ect variations in load ‘conditions.
lating oil pressure for modulating -a compressor
As a result, the disadvantages of-step control are
capacity control responsive tovariations inter-n
eliminated and in?nite variation in (capacity 25 ..peratureqconditions of an area served-‘by .an.=air
throughout the effective range of the compressor
conditioning system of which aacompressortis‘ a
may be achieved. Thus as the compressor oper
ates under decreasing or increasing partial load
Considering the drawings, similar designations
conditions, the valve action ‘varies directly to
compensate for such changes in condition.
A feature or the invention resides in the use
.of oil pressure variedresponsive to changes in
load conditions to govern the adjustable-posi
referring to similar’ par-ts, “numeral. 5 generally
designates a compressor having .aiplura'lityi of
cylinders 6, 3,08 andl9. The compressor maybe
of conventional design and includes .a crank
case .10, the bottom of ‘which serves as an‘._ oil
sump ‘l I; .and the operating mechanism includes
Another feature of the invention resides inthe
the usual "crank shaft [2, pistons 13, connecting
provision of a pair of springs, one at ~each'side
.rods 22 and other structural elements normally
employed for compressing gases, all of which
of a-suction valve, the extent v‘of compression ‘of
one of them being dependent upon variations in
form no essential part-of‘the-invention, but which
.oil pressure reflecting-changes in load conditions.
it will be understood are‘present to forman oper
Another featurellof the invention covers the 40 able compressor.
use of an oil actuated ipiston operating :a'lever
In various applications to 'whichiacompressor
device for varying ‘the-compression of a spring
may ‘be applied, more especially a refrigerant
tioning of a suction valve.
bearing against one side of a suction valve to
determine its time of - closing as the load ' varies.
compressor, the need for varying the output ‘re
sponsive to di?erent or changing loa'd {require
Another feature ‘covers utilizing the pressure 45
ments is often great. Applicant provides a mod
control adapted to be applied to one‘ or
with the pressure exerted 'by ‘a piston ‘of the re
more cylinders of a compressor for governing the
frigerant compressor for governing the time of
action of the suction valve serving the cylinder to
. closing of a suction valve.
‘Another feature covers theregulation of ‘oil 50 which the control is applied.’ ‘Unlike previous
.expedients for controlling compressor capacity,
pressure for actuating the ~~positioning of the
the action of applicant’s valve is -so regulated
‘suction valve responsive to temperature ‘or pres—
that the time and ‘extent of opening of :said
‘sure conditions of anarea servedby the system
applied by'anoil actuated piston .in combination
of whichthe compressor is a part.
valve is correlated with variations inload re
Another feature .of the invention .assures the 55 .quirements with the result. that compressor 'out-.
put will automatically be increased or decreased
exactly to compensate for changes in load.
First considering the general diagrammatic ar
rangement of Fig. 1, pump l4 supplies oil from
sump H to feed line l5. The oil passes through
ori?ce I6 and then applies pressure within sup
ply line |‘| depending upon the amount of oil
?owing through regulating line |8 which is routed
to control valve l9 from which the oil fed there
of collar 50. As the cup tends to rise upon ex
pansion of the bellows, the action of spring 5|
will serve to close the valve and make the pins
ride up, whereas when the bellows contracts, the
pressure of spring 41 which is then greater than
the pressure of spring 5|, will cause the pins to
push down the collar 50 and hence open the
In practice, with the system shown in Figs. 1
to is returned to the sump through return line 20. 10 and 2, including a control valve l9 as shown in
Fig. 3, it will be noted that when the compressor
Suction pressure connecting line 2| subjects con
trol valve | 9 to the suction pressure in mani
fold 52.
is started up, substantially no oil pressure will
exist at the moment of starting. Consequently,
there will be no oil pressure in line H and the
Now considering the detailed view shown in
Fig. 2 of applicant’s modulating control as ap 15 piston 24 of power element 23 will be down.
Thus, actuating shoes 3| will be in uppermost
plied to any desired cylinder, a power element
position holding spring supporting ring 32 in top
23 has a piston 24 therein with a piston rod 25
position with suction valve 3'! completely open.
connected to a forked operating lever 26 at pivot
The compressor will, therefore, start in an un
21. The lever is connected at pivot 23 to power
element cover 29. A spring 30 is positioned about 20 loaded condition, as is most desirable.
Under practical operating conditions, when
piston rod 25 between the inverted piston head
the suction pressure is above the point for which
24 and cover 29. Actuating shoes 3| at the ends
regulating screw 48 on valve I9 is set, then the
of the forked operating lever 26 bear against
modulating mechanism will be inoperative.
spring supporting ring 32 to cause the ring to
move up and down upon the outer wall of the 25 However, upon a drop in suction pressure below
said set point, the valve needle will open to re
cylinder guided by bodyportion 33 of ring 32
duce the oil pressure in an amount depending
which is positioned concentrically about the cyl
upon the reduction in load, as re?ected by the
drop in suction pressure. The e?ect is to apply
A plurality of capacity control springs 34 are
a varying pressure upon the power element 23
mounted upon supporting ring 32 within suction
ports 35 of cylinder sleeve 36.
Suction valve 31 is positioned between capacity
control springs 34 and suction valve springs 38,
the valve springs being‘recessed in the usual man:
ner within valve plate 39.
The control valve l9 which regulates the pres
sure applied to power element 23 is shown in de
tail in Fig. 3. The oil from pump l4 feeds into
corresponding to the variation in partial load.
Consequently, the suction valve 31 will be opened
at a point in the stroke and then closed respon
sive to building up of pressure upon the com
pression stroke to provide less than full com
pressor capacity corresponding to the drop in
In Fig. 4, a modi?ed form of control is illus
trated in combination with an air conditioning
40. The oil passes through drilled passageway 40 system served by a compressor equipped with
applicant’s invention. In this case, a multi-cyl
4| past valve seat 42 into passageway 43 depend
inder compressor has one or more of the cyl
ing upon the position of valve needle 44, the po
inders equipped with the capacity control already
sition of which is determined by the action of
shown in Fig. 2. The gas discharged from the
bellows element 45.
compressor goes to a condenser 54, receiver 55,
The bellows element includes cup 46 having
then through expansion valve 56 to an evaporator
therewithin a range adjustment spring 41 whose
51 employed for cooling the air of enclosure 53;
compression is adjusted by the regulating screw
the gas returning to the compressor through line
48. The cup actuates a series of push pins 49
59 to close the usual cycle.
which, in turn, bear against collar 59 for posi
Instead of operating applicant’s modulating
tioning the valve needle. The collar has exerted 5'
control responsive to variations in suction pres
thereagainst the pressure of spring 5| in oppo
sure, a regulating device 60 is provided opera
sition to the force supplied thereto by the pins.
tive responsive to a thermostatic bulb 6| within
Suction pressure re?ecting the condition in
the conditioned enclosure 58.
suction manifold 52 is applied through line 2|
The position of diaphragm 62 of regulating de—
and passage
is that53astothe
inside of
45. The
Vice 6!] depends upon the pressure within lower
diaphragm chamber 63 and the spring pressure
cup 46 will move downwardly to cause pins 49
of spring 64.
to open the valve, causing an increase in oil to
Upon a decrease in room temperature, indi
?ow through regulating line |8 with the result
cating a drop in load, diaphragm 62 will tend to
that oil pressure through line H exerted upon ,
move down to open the valve 65 in an amount
power element 23 will drop. On the other hand
corresponding to the reduction in load. 0n the
on an increase in load, when the suction pres
other hand, upon an increase in temperature
sure rises, the pressure in the bellows will corre
within the conditioned enclosure the pressure
spondingly rise to overcome the pressure of spring
within chamber 63 will increase to the point
41, with the result that spring 5| will serve to
where it overcomes the pressure of spring 64
tend to push the valve needle to closed position.
and correspondingly tends to close the valve 65.
The pins 49, in this event, will not be able to
The oil pressure in line II will then rise to cause
overcome the pressure of spring 5| since the
the piston in the power element to go up where
cup will be su?ciently lifted due to the increased
pressure within the bellows to keep the pins from - upon the supporting ring 32 will drop and suc
tion valve 31 close to resume full load opera
pushing downwardly collar 59 in which the valve
tion. Of course, where partial load conditions
needle is held.
still obtain, the action will be the same as with
The push pins 49 ?t within holes in the valve
the control of Fig. 3 in that the time and ex
casting so that they ride up and down resting
valve l9 through regulating line H? entering port
against the bottom of the cup 46 and the top 75 tent of opening of the suction valve will be
governed by the partial load condition which reg
spondingly varying the pressure applied against
ulates the spring action on the valve as opposed
to the compression on the'upward stroke of the
said suction valve.
4. In combination with a compressor, includ
ing a modulating capacity control therefor, a
suction valve, a pair of springs positioned on
opposite sides of the valves, means for compress
ing one of the springs in accordance with varia
Thus, applicant provides a sensitive modulat
ing control with unlimited range for every load
condition which arises over practical operating
conditions. The compressor starts in unloaded
tions in load affecting the compressor.
Immediately thereafter, however, it
5. In combination with a reciprocating com
may operate at full load conditions; and there 10 pressor, a modulating capacity control for regu
after whenever partial loads are encountered the
lating the time of closing of a valve, said com
capacity will be increased and decreased to com
bination including a valve, means for applying a
pensate for such variations in partial load to
force in one direction against one side of said
give exactly the capacity needed to maintain any
valve, means for applying a force in the opposite
given condition.
15 direction against the opposite side of said valve,
It will be obvious to those skilled in the art
that various changes may be made without de
parting from the spirit of the invention and
therefore the invention is not limited to what is
shown in the drawings and described in the speci
?cation but only as indicated in the appended
I claim:
1. A system of modulating capacity control for
reciprocating compressors comprising means for
pumpingoil, an oil actuated power element, a
line including an ori?ce therein for delivering oil
under pressure to said power element, a modu
lating means operative responsive to variations
in load conditions affecting a compressor for 30
means for varying the force applied against the
opposite side of the valve responsive to varia
tions in load affecting the compressor.
6. In a combination of the character described,
a compressor having a plurality of cylinders, a
modulating capacity control applied to certain
of said cylinders, said capacity control including
an operating lever on each of a plurality of said
cylinders, an oil pressure actuated power ele
ment controlling the movement of said lever, a
spring supporting ring adapted to be variously
positioned by said lever, a capacity control spring
supported by said ring and bearing against one
side of said valve, means for supplying spring
pressure against the other side of said valve, an
oil pump for lubricating the compressor, and
tion valve, and means operated by the power
means for supplying oil from said pump to the
element for varying pressure applied against the
power element at a pressure depending upon the
valve to determine its time of closing.
load aifecting the compressor to govern the pres
2. A modulating capacity control for a recipro 35 sure exerted by said ?rst mentioned spring bear
cating compressor, including a suction valve, a
ing against the valve.
suction valve spring bearing on one side of the
'7. A system for varying the output of a com
valve, a capacity control spring bearing against
pressor including a valve in the compressor,
the valve on the other side thereof and means
means for. exerting spring pressure on opposite
responsive to varying oil pressure for compress 40 sides of the valve, a power element operated by
ing the capacity control spring depending upon
oil pressure for modulating the spring pressure
variations in load conditions affecting the com
applied to one side of the valve, an area to
modulating the oil pressure in said line, a suc
3. A modulating capacity control for recipro
cating compressors including a power element, a
piston within the power element, means for ap
plying oil pressure to said power element op
posed by spring pressure thereon, an operating
lever under control of the power element, a suc
tion valve, means for applying pressure against
the suction valve, said means being actuated by
be conditioned served by the compressor, and
means operative responsive to variations in at
mospheric conditions within said area for vary
ing the oil pressure applied to said power ele
ment in such a manner that said spring pres
sure controlled thereby is varied to adjust the
time of closing of the valve to regulate capacity
output of the compressor" in accordance with
changing load conditions in said area.
said lever and means for varying the oil pres
sure exerted on said power element for corre
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