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Патент USA US2135248

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22,135,248
a. s. AKK‘MAN
COEPRESSOR CONTROL
Filed Biay 26, 1956
£25
‘
557>236 2/6 2/2 203 238
220E
276
4 Sheets-Sheet l
~ 200
206"
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2
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20/
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Q
5
3.
27$
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2/42
2/2
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2/0
iNVENTOR
EURTON EL AIKMAN
ATTORNEY
Nov- 1, 1938-
a. s. AIKMAN
- 2,135,248
COMPRESSOR CONTROL
Filed May 26, 1936
4 Sheets-Sheet 5
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INVENTQR
BURTON E. AIKMAN
BY
ATTORNEY
2,135,248 '’
Patented Nov. 1, 1938
UNITED STATES PATENT OFFICE
> '
'
'
oomrlmsson
balsam
ooN'raoL
_
.
Burton 8. Alirman, Wiikinaburg, Pm, assignorto'
The Westinghouse Air Brake Company, Wil
merding, Pa., a corporation of Pennsylvania
Application May 26, 1936, Serial No.‘81',862
'3
(oi. sac-4)’
'
This invention relates to a control system for which is responsive to the‘ pressure of the ?uid
a ?uid compressor and for the compressor driving compressed by the compressor and which regu
means, and more particularly to a control system lates the pressure of. the ?uid compressed by the
responsive to the pressure oi’ the ?uid compressed compressor without the use of toggle lever and
5 .by the compressor for loading and unloading the spring combinations or without the use ‘of valves
compressor and for also controlling the com
pressor driving means.
It is customary in many ?uid compressor in
stallations. to control the. compressor driving
operating against pressures higher than atmos
pheric pressure.
'
Another object of the invention is to provide
a compressor control system of the type described
to eiTeot operationof the compressor when this
and having means to adjustably vary the ?uid 10
pressures which the system is adapted to main
tain without a?ecting in ,a substantial manner
pressure falls below a predetermined value and
to continue operation of the compressor until the
control mechanism’,
' 10 means in response to variations in the pressure
of the ?uid compressed by the compressor so as
the forces available for actuating portions of the
pressor increases to a higher predetermined value.
In the control systems now’ in use it is cus
A further object of the invention is to‘provide 15
a compressor control system of the type described
and which is adaptedfor use in connection with
tomary, on an increase in the pressure of the
?uid compressed to the predetermined .value, to
or by an internal combustion engine.
15 pressure of the ?uid, compressed by the com
a compressor driven by either an electric motor
Another object of the invention is to provide a
20 actuate the means for controlling the compressor
driving means, either before the compressor is compressor control system for use in controlling
unloaded, or simultaneously with operation of‘ a compressor driven by an electric motor, the
the compressor unloading means, with the result control ‘system including a switch for controlling
that this control of the driving means is e?’ected the circuit to the driving motor and having im
25 while the driving me'ans is under substantially proved means to produce a blast of air across the
switch contacts when the contacts are opened in
its maximum load.
' .
~
order to quickly extinguish the are which is
In many installations the driving means is an
‘
electric motor and the control system includes a formed between these contacts.
A further object 01 the invention is to provide
switch which opens and closes the circuit to this
30 driving motor. If this switch isopened while the. ' an improvedcompressor control system.
Other objects of the invention and features of
driving motor is under maximum load the switch
will be required to interrupts, heavy current and novelty will be apparent from the following de
considerable arcing and burning of the switch scription taken in connection with the accom
panying drawings, in which
contacts will result. If the circuit to the com
Fig. 1 is a diagrammatic view of a ?uid com35 pressor driving motor is not interrupted until
‘after the compressor is unloaded, which results pressor driven by an “electric motor and equipped
with one embodiment of the control system pro
in a. substantial reduction in the load on the driv
.
ing motor and a corresponding reduction in the vided by this invention;
Fig. 2 is a diagrammatic view of a. ?uid com
current taken by the motor, the strength of the
40 circuit to be interrupted by thecontrollswitch pressor driven by an internal combustion engine
and equipped with another embodiment of the
will be greatly reduced and the arcing and'burn
- Aug of the switch contacts vwill be reduced to a
I
29
25
30
M
‘35
40
control system provided by this invention;
Fig. 3 is an enlarged fragmentary view, largely
Itmis one object of this invention to provide a in section, of a portion of the apparatus employed
45 compressor control system for controlling the in- the control system shown in Fig. 2 of the draw- 45
ings;
.
operation 01 a compressor and of an'electric driv
Fig.4 is an enlarged sectional view of the con
ing ‘motor therefor, and which operates to unload '
the compressor and thereby reduce the load on trol apparatus‘employed in connection with the
. the compressor driving motor before the circuit compressor shown in Fig. 1 of the drawings;
Fig. 5 is a sectional view taken substantially 50
50 to the driving motor is interrupted so that the
) '
.
strength 01 the circuit which must be interrupted ' along the line 5-5 of Fig. 4; I
Fig. 6 is a view similar to Fig. 4 and showing
will be at a minimum at the time the switch is
the‘control apparatus in the position to unload
the compressor and‘ to interrupt the circuit to
‘A‘iurtiier object of the‘lnvention is to pro
as
55 vide a control system for a. fluid compressor the compressor driving motor;
.
minimum.
opened.
v
‘
l
.
4
i
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.
2
2,185,248
. Fig. 7 is an enlarged sectional ‘view of a modi
face of a diaphragm 82 which is subject on the
?ed form of compressor control apparatus em
bodyin'g this invention;
'
Fig. 8 is an enlarged sectional view of the con
' other side to the pressure of the fluid in a chamber
64 which is connected by way of a pipe 66 with
the reservoir 2 into which the compressor com- '
trol apparatus employed in connection with the
presses fluid.
along the line 9—9 of Fig. 8.
,
The rounded portion 58 of the arm 56 of the
member 26 is engaged by means of a spring seat
‘I0 which is slidably mounted in a bore in the
plunger 80. A coil spring ‘I2 extends between the
compressor shown in Fig. 2 of the drawings; and
Fig. 9 is, a sectional view taken substantially
'
Referring to Fig. 1 of the drawings there is
10
spring‘seat ‘I0 and a latch piece ‘I4 which is slid
10 illustrated therein a ?uid compressor I, which
ably mounted in a bore in the plunger '80, and _
may be of any suitable well known construction,
and which compresses fluid into a‘ reservoir 2 by
which is provided with an annular recess into
way of a pipe 4. The compressor I is driven by ' which extends a pin _'I8 which projects into the
means of an electric driving motor 6, while a bore in the plunger 80. The latch piece ‘I4 is
15 control device, indicated generally by the refer-_ provided with an extension ‘I8 of reduced
ence numeral 8, is provided to control the load
The casing section 80 is, in addition, provided
ing and unloading of the compressor and to also
with a bore in which is mounted a piston 80
1cgniérol the supply of current to the driving mo
which is prevented from rotating in the bore by
20. The construction of the control device 8 is best means of a pin 82 which extends into a groove 20
shown in Figs. 4, 5 and 6 of ‘the drawings, and as 84 in the face ,of the wall of the piston 80. The
therein illustrated comprises a hollow 'casingil0 piston 80 also has formed thereon at a point '
diameter.
r
.
.
-
'
.
-
substantially diametrically opposite the groove 84
which is interposed air straining material, such as a groove 86, and, as'will hereinafter more fully
25 curled hair indicated at I2, which is con?ned be _ appear, the projection ‘I8 on the latch piece ‘I4. is 25'
tweenperforated plates I4 and I6. One end of adapted at certain times to extendvinto this groove
' having a passage extending therethrough in
the passage through the, casing I0 opens on a
mounting face formed on the casing and adapted
to be secured against .a similar mounting face
30 \formed on the compressor surrounding the in
take ‘passage I8 leading to the inlet valve of the
compressor.
‘
The other end of the passage through the cas~
ing I0 terminates in a substantially circular open
35 ing in the face of the casing I0 vwhich is sur
rounded. by an annular sealing gasket 20, which
may be formed of any suitable material such as
rubber.
,
v
The control device 8 has associated therewith
40 valve means adapted to control the ?ow of ?uid
to the passage through the casing I0, and this
valve means comprises a valve disc 22 which is
pivotally supported by-means of a pin 28 on an
arm 24 of a member 28.
45
V50
.
The member 28 is pivotally supported from a
ground.
'
The stationary contacts 90 and 92 are secured;
on a member I00 which is formed of suitable in
sulating material and is mounted in a recess in ,
casing section 80 by means of a pin ‘82 and is , the member 90 so as to form a chamber I02- en
yieldingly urged in a counterclockwise direction,
as viewed in Fig. 4 of the drawings, by means of
a coil spring 84 which has one end connected to
the pin 28 and has its other end connected to a
threaded eye 86 which extends through an open-_
ing in the casing section 80 and has secured
thereon a knurled nut 88.
ber 44 is yieldingly urged into engagement with
the roller 42 by means of a spring 48 which has
one end secured to a portion of the casing section
80 and has its other. end secured to a threaded
eye 50 which extends through an opening in the
meénsbzer 44 and has secured thereon a knurled
nu
.
'
The member 44 has a recess 84 formed in ‘the I
face thereof, and in one position of the arm 40 of
the member 28 the roller 42 extends into the
recess 54.
,
,
closing the stationary and movable contacts.
The stationary contacts 90 and 92 have re
stricted openings I04 and I08 extending there
through and opening 'on the faces of the con
tacts which are adapted tolbe engaged by the
movable contact 88.
The piston 80 has at one side thereof a -
’ , ,
The member 28 has an arm 40 formed integral
therewith and this arm carries at the end thereof
a roller 42 which is engaged by a member 44
which is pivotally secured by means of a pin 48
to a portion of the casing section 80.. The mem
65
to hold the piston 80 in one of its positions.
The piston 80 has secured on the face thereof
a movable contact 88 having spherical end por
tions which are adapted to engage stationary 30
contacts 90 and 92. The movable contact 88 is
,secured to the piston 80 by means of a screw .94
and is insulated from the piston by means ofin
sulating members 96 and 98.
The stationary contact 90 is connected by way 35
of a wire 9| with one terminal of the driving
motor 6, while the stationary contact 92 is con
nected by way of a wire 98 with one terminal of
the source of current supply. The other terminal
of the source of current supply and the other
terminal of the driving motor are connected to
'
The member 28 has an arm 88 formed integral
70
therewith and thirarm has a round portion 88
formed on ‘the end thereofwhich extends into a
hollow plunger 60 which is mounted in a bore in
the casing section 80. The plunger 80_is pro
75 vided with an enlarged head which engages one
chamber I 08 which is constantly connected by
way of a passage IIO with the passage through
the casing section I0 and thereby with the intake
passage I8 of the compressor I.
-
The piston 80 has an opening H4 extending
therethrough and communicating with the
chamber I08 and with the chamber I 02. The 00
flow capacity of the passage H4 is less than the
combined ?ow capacities of the passages I04 and
I 08 through the stationary contacts 90 and 92
respectively.
'
The piston 80 is urged by means of a spring
» II5 to aposition to press the movable contact 88
against the stationary contacts 90 and 92 and
complete the circuit between these contacts.
The control device 8 is shown in Fig. 4 of the
drawings in the position to complete the circuit
to the compressor driving motor, to effect loading
of the compressor, and with the pressure of the
?uid compressed vby the compressor below the
value to whichthe control device is adapted to
05
3
£,3%§,248
respond to unload the compressor and to inter-_ in the chamber I08 as this chamber communi
rupt the circuit to the driving motor.
On -an increase in the pressure 'of the ?uid
compressed by the compressor I there will be a
similar‘increase in the pressure 'of the ?uid in'
cates with the compressor intake-passage, by way
of the passage I_l0. Fluid ?ows from chamber
I 02 at one side of piston 00 through the re- .
stricted port 'I I4 in the piston to chamber I08,’ 5
the chamber 64 as this chamber communicates
but since ‘the ?uid pressure ‘in chamber I08 is
with the reservoir 2 by'way of ‘the pipe 66.
reduced at a greater rate than ?uid can ?ow
When the pressure of ?uid in chamber 64 has
through said-port, the piston 80 will be moved to
the right, against the resistance of the spring III‘
by the higher atmospheric pressure in cham- ‘10
been increased to a predetermined degree su?i
10 cient to overcome the/‘opposing pressure of the
spring 34 which acts through the arms 24 and '
56 and the plunger 60 to'oppose movement of the
diaphragm, said diaphragm, will be moved up
wardly, so as to cause the member 26 to be moved
15 in a clockwise direction about the pin 32.
On this movement of theimember 26 the arm.
24 is moved and it will move the valve‘disc 22
closer to the sealing gasket 20.
.
In addition, on this movement of the lever 26
her I02.
u
‘.
‘
'
On this movement of the piston 00 the bridging
contact 88 is moved awayirom the stationary
contacts 90 and 92. When the bridging contact
08 is moved away from. the stationary contacts" 15
and 92 arcs may be formed between the station
ary contacts and the bridging contact, but as‘the
compressor has already been unloaded before the
bridging contact is moved away from the station
the arm 40 thereof will be moved and the roller 42
will move across ‘the face of the member 40
towards the depression 54. The face of the mem
ber 44 is arranged so as-to o?er substantially no
opposition to movement of the roller towards ‘
ary contacts the load on the driving motor 01’ the “20
compressor is reduced to a minimum, and the
current required by the motor is also reduced to a
minimum so that the size of the arcs which are
the depression 54.
ing motor is at a minimum.-
'
'
formed ,on interruption of the circuit to the driv- __
_
.
-
On this movement‘of the plunger 60 the latch
‘ 0n movement of the piston 80 to the right, as
piece ‘I4 will be moved towards the piston 80, and
viewed in Fig. 4 of the drawings, there will be an
after a predetermined amount of movement of increase in the volume of the chamber I02 and a _
the plunger 60 upwardly the projecting portion _ corresponding reduction in the pressure of the‘
30 78 on the latch piece 14 will ‘engage the face of . ?uid in this chamber. As a result of the_reduc- so
tion in the pressure of the ?uid in the chamber
the piston 00 so that on further upward move
» ment of the plunger 60 the plunger will move ' I02 from this cause, as well as from the ?ow of
relative to the latch piece ‘I4 and will compress ?uid therefrom through the passage II4 to the. .
the spring '12. ._
' to
M
,
.
After a predetermined amount of movement
of the plunger_ 00 the member 26 will be moved'
an amount sufficient to move the valve disc- 22
very close to the sealing gasket 20 so as to sub
stantially restrict the rate at which air may
40 ?ow from the atmosphere to the passage through
the casing section i0 leading to the inlet passage
which form between the stationary contacts and ,
the bridging contact 88 and serves to cool and
of the compressor.
extinguish these arcs.
r
-
As the valve disc 22 approaches the‘ sealing
gasket 20, the ?ow of atmospheric ?uid to the
inlet passage of the compressor is substantially
restricted, so that the atmospheric pressure act
ing on the outer face of the disc 22 against the
partial vacuum created by the suction of the com
pressor at the opposite side of the disc by the
movement of the disc toward its seat will cause
the rapid movement of the disc to its closed
position.
>
.
On movement of the valve disc 22 to the seated
or L1
chamber I08 and thence to the compressor in
take-passage, the pressure of the ?uid in the
chamber I02 will be substantially below that of
the atmosphere and air will ?ow through the
passages I04 and “Wm the chamber I02 and is
discharged substantially in the zone of the arcs
‘ .
As long as the compressor continues to operate
there will be a,high degree of vacuum in the com
pressor' intake passage and ?uid will continue to
?ow thereto from the chamber I02 throughthe
passage‘lid, the chamber I08 and the passage
5 l0. _ As a result air will continue to ?ow through
the passages I00 and I05 to the chamber I02 to
extinguish the arcs formed on the interruption of [50
the circuit to the compressor driving motor and
to cool the switch contacts as long as the com-
,
pressor continues to. operate.
position the member 26 is moved in a clockwise .
I When the piston. 00'has moved substantially
direction, thereby moving the arm 40 across the
to the end of the bore in} which it is located the
'
face of the member 54 so that the roller 42 is in projecting portion ‘I0 of thelatch piece 14 is
alignment with the recess 54, whereupon the. forced into the groove 85' in the piston 80 by the
spring :38 causes the member 44 to move about spring 712 and extends beyond the shoulder at
the pin 66 so that the recessed portion 56 engages the end of the groove 80 so as to prevent return
00 the roller 52.
.' '
On movement of the valve disc 22 to the seated
position, because of the force exerted on the
valve disc as a result of the partial vacuum'in
the compressor inlet passage‘j'there will be a re
duction in the force exerted by the'spring 30
on the plunger 00 and the ‘plunger 00 will be
moved upwardly by' the ?uid under pressure in
the chamber be acting on the diaphragm 62 into
engagement with the shoulder I20 on the casing
movement of the piston 80 by the spring H5.
,
\The control device 8 is now substantially in
the position in which it is shown in Fig. 6 of the
drawings. As the bridging contact 08 has been
moved away from the stationary contacts 90 and
92 the circuit to the compressor driving motor is
interrupted and this motor ceases to operate.
The compressor, therefore, will not be driven and
the partial vacuum in the compressor intake pas
sage it will be gradually dissipated by the flow
section 30, thereby increasing the amount of
of air thereto from the atmosphere through the ,_
compression of the spring ‘I2 and more, ?rmly
passages ltd-and I06 through the stationary'con
‘ pressing the latch piece "against the piston 30. ' tacts 90 and 02, the chamber 802, the passage Ill '
On a'reduction in the pressure of, the ,?uidin
through the piston 00, the chamber I00 and
the compressor intake passage I8 there will be
75 a similar reduction in the pressure of the ?uid
thence'by way of the passage H0. The piston 80
will be urged to the left, as viewed in Figs. 4 and
,
'
4
98,185,248
6 of the drawings, by the spring I I5 but its move-
ment will be prevented by the projecting portion
18 on the latch piece 14.
As the pressure in the compressor intake pas
sage increases to atmospheric pressure the force
exerted on the valve disc 22 and tending to main
~ tain it in engagement with the sealing gasket 20
is reduced, but this valve is held in the seated
position by the ?uid under pressure in the cham
10 ber 64' acting through the diaphragm 62 and
plunger 60, and by the ‘spring 48 acting through
the member 44 and pressing upon the roller 42
_
.
disc 22 will be moved against the spring 34 to ,
unload the compressor will be increased.
Similarly, if the tension on the spring 34 is. 7
decreased the pressure to which the ?uid in the
reservoir 2 and in the chamber 64 must build up
before the valve disc 22 ‘will be moved against
the spring 34 to unload the compressor will be
decreased.
'
_
.
As the means determining the di?erence in the
pressure at which the control device operates to 10
interrupt the circuit to the driving motor and the
pressure at which it operates to complete the cir
carried by the arm 40 of the member 26 on which - cult to the driving motor is not affected by this
the valve disc 22 is mounted. Because of the’ change in the adjustment vof the spring 34 any 15'
change in the adjustment of the spring 34 to
15 shape of the depression 54 in the'member 44
movement of the roller 42 out of the depression is - vary the pressure‘ at which the control device
v20
will produce a similar change in the pressure at
which the control device operates to initiate oper
to effect movement of the roller 42 into ‘the de- -
ation of the compressor.
pression 54.
When the pressure of ?uid in the reservoir 2
and in chamber 64 is reduced su?iciently, the
force of the spring 34 will act against the reduced
25 pressure in chamber 64 and any resistance to
movement offered by the spring 48, to move the
member 26 in a counter-clockwise direction, so‘
that the disc 22 is moved away from its seat tov
thereby open the compressor intake passage to
the atmosphere.
‘ ' On this movement of the member 26 the roller
42, which is carried by the arm “of the member
26, moves out of the depression 54 in the member
44, and in moving out of the depression 54 the
35 roller v42 moves the member 44 in a clockwise di
rection about the pin 46,' thereby increasing the
tension'on the‘ spring 48. Afterthe initial move
ment of the roller 42 out of the depression 54 it
-
operates to interrupt operation of the compressor
prevented until the force tending tomove the
roller in the opposite direction is reduced to a
value substantially below that initially required
' engages the flat face on the member 44 so that
40 further movement of the roller 42 does not effect
a further increase in the tension on the spring 48.
On movement of the member 26 by the spring
84 the round end 58 of the arm 56 engages the
' plunger 68 and moves the plunger downwardly,
‘ as viewed in Figs. 4 and 6 ‘of the drawings, and
and on this movement of the plunger 68 the pin
~ 16 engages a shoulder on the latch piece 14 and
retracts this latch piece so that the projecting
portion 18 on the latch piece 14 is moved out of
the groove 86 in the piston 80, thereby releasing
50
the piston 88.
'
-
20
"
I The control device provided by this invention
also incorporates means by which the difference
in the pressure at which the operation of the
compressor is interrupted and the pressure at
which the operation of the compressor is initiated 25
may be adjustably varied. This is accomplished
by turning the knurledv nut 52 and thereby vary
ing the tension on the spring 48. If the tension
on this spring is increased the force exerted by
the spring and opposing movement of the roller 30.,
'42 out of the depression '54 after movement of the
roller into this depression will be increased, and
hence the pressure of the fluid in the chamber
64 must decrease to a greater degree before the
force exerted by this ?uid on the diaphragm 62 35
and through the plunger 60 on the member 26
will be enough less than the force exerted on
the member 26 by the spring member 34 that the
member 26 will be actuated to. move the roller 42
out of the depression 54 and to move the latch, 40
piece 14 to release the piston 80.
'
Similarly, it the tension on the spring '48- is
decreased,\the force exerted by this spring and
opposing movement of the roller 42 out of the
depression 54 after ‘movement of the roller into
this depression will be decreased, and hence the
pressureof the ?uid in the chamber 64 must only
decrease to a somewhat lesser degree before the
force exerted by this ?uid on the diaphragm 62 .
and through the plunger 60 on the member 26 50
will be enough less than‘ the force exerted on the ,
On the release of the latch piece 14 the piston
member 2'6 by the spring 34 sothat the member
viewed in Figs. 4 and -6 of the drawings, thereby
moving the bridging contact 88 into engagement
with the stationary contacts 90 and 92, thus com
pleting the circuit to the driving motor 6 for
the compressor so that the motor is started and
the depression 54 and to move the latch piece
80 is moved by the spring H5 to the left, as - 26 will be actuated to move the roller 42 out of
operates the compressor to'compress ?uid into.
60 the reservoir 2.
.
When the pressure of ?uid in the reservoir is
again increased to the predetermined value at
which the control device 8 operates to cut the
compressor out of operation, the operation of said
device as hereinbefore described is repeated.
,
The control device provided by this invention
incorporates means by which the pressure at
.which the control device will operate to unload
the compressor and to interrupt the circuit to
14 to release the piston 80.
'
It will be seen that the control device pro
'55.
vided by this invention incorporates means re-'
sponsive to the pressure of the ?uid compressed
by the compressor for unloading the compressor
and for interrupting the circuit to the driving 60
motor of the compressor, and that it.‘ operates so
as to unloadthe compressor and reduce \the load
on the driving motor before the circuit to the’
driving motor is interrupted. with the result that
the strength of the current to be interrupted is 65
at a minimum. .
_.
It will be seen also that the control device pro
vided by this invention incorporates means to
create a blast of air between the contacts at
the-time
they are separated so as to cool and
the driving ‘motor may be adjustably varied. ,
This is accomplished by turning the knurled nut extinguish the, arcs which are formed at this
38 which varies the tension on the spring 34. If time, and that the means for creating this blast
of air is responsive to operation of the com
the tension on this spring is increased the pres
sure to which the fluid in the reservoir 2 and in pressor so that the air blast continues as long
the chamber 64 must build up before the valve as the compressor continues to run.
2,185,248
vIt will be seen, in addition, that the control
device provided by this invention is not depend
ent upon toggle lever‘ and spring arrangements
and does not employ valves operating against
pressures above atmospheric pressure.
In addition it will be seen that the control de
vice provided by this invention incorporates
‘means to adjustably vary the pressure to which
the'device is adapted to respond to interrupt op
10 eration of the compressor, and also includes
means to adjustably vary the di?erential be~
tween the pressures at which operation of the
compressor is interrupted and at which opera
tion or the compressor is initiated.
In Fig. 7 of the drawings I have illustrated an
other form of control device embodying this in
vention and adapted for use in connection with
a ?uid compressor driven by an electric motor.
The control device illustrated in Fig. '7v of the
20 drawings comprises a body indicated at‘ I30 hav
‘ing a chamber therein in which is positioned
suitable airstraining- material, such as curled
. hair indicated at I32, and which is con?ned by
25
’ s
in the‘ casing section I30 in which is mounted a
piston I60.
The piston I30, which is mounted in a borev
in the casing section I30, is provided with a
groove I62 into which extends a pin I84 to pre
vent rotation of the piston in this bore. _
The piston I60 has formed on the opposite side
from the groove I62 another groove I36 into
which is adapted to extend, as will hereinafter
more fully appear, the end of the plunger I68.
10
The piston I80 is yieldingly urged to the left,
as viewed in Fig. 7 of the drawings, by means of
a coil spring I86 which is mounted in a chamber
I90, which is connected by way of a passage I92
to the chamber I38, and thereby to the compres 15'
sor intake passage.
Communication’ between
the chamber I90 and the chamber I36 through
the passage I92 is controlled by means of a valve
I96.
-
.
The piston I00 has secured thereto, but in 20
sulated therefrom, a bridging contact I96 which
is adapted to engage stationary contacts I88 and
200 which extend through an insulating member
means '01’ perforated plates I34 and I36.
The chamber I38 at one side of the air strain
ing means I32 communicates with an opening in
a mounting face on the body I30 which is adapt‘
ed to be secured to a similar mounting face on
202. The contact I98 has secured thereto'a wire
204, which is secured to one terminal of the driv 25
ing motor for the compressor to be controlled,
while the contact 200 has secured thereto a wire
206 which is connected to one terminal of. a
a compressor so that the chamber I38 is in com
source of electric current.‘
.
The member 202 forms one wall of a chamber 80
80 munication with'the intake passage of the com
206 enclosing the stationary and the bridging con
pressor.
The chamber I40 on the other side of the air tacts controlling the circuit to the driving motor.
straining means I82 is open to one face of a dia ‘The contact I96 has a passage 2I0 extending
phragm I42, which is subjecton the other side to therethrough and'opening on the face of the con
the pressure of the ?uid in a chamber I44, which tact which is engaged by the bridging contact 35
I96, while the contact 200 has a passage 2I2 ex?
is connected by way of a pipe I46 with the reser
voir into which the compressor to be controlled tending therethrough and opening on the face of
compresses ?uid.
this contact which is engaged byv the bridging
'
One face of the diaphragm I42 is engaged by
contact I96.. The piston I30 has a restricted pas- _
a plunger I43 which is mounted in the .chamber
I40 and which carries a valve I50 which is adapt
ed to engage a seat rib I52 .to control communi
sage 2I4 extending therethrough and-communi
eating with the chamber I80 on‘ the spring side
cation between-the chamber I40 and the atmos
_
40,
of the vpiston and with the chamber 206.
‘
This control device is shown in the drawings
in the position to effect loading of the compressor,
to‘ complete the circuit to the compressor‘driv 45
of a bell crank I56 which is pivotally supported ing motor, and with the pressure of the ?uid
on a pin I56. The arm I54 of the bell crank I56‘ " compressed by the compressor below the value to
which the device is adjusted to respond to un
is yieldingly urged in a counterclockwise direc
load the compressor and to interrupt the circuit
tion, as viewed in Fig. 'I of the drawings,‘ into en
g‘agement with a stop I65 by means of'a coil to thecompressor driving motor.’ The compres 50
50
spring I60 which is secured to an eye I62 which ' sor, therefore, will be operated by the driving mo
extends through an opening in the arm I54,.and tor and will compress ?uid under pressure intov
which has mounted on the end thereof a nut I60 the reservoir associated with the compressor.
On an increase in the pressure of the ?uid in
by means of which the tension on the spring I60
the reservoir associated with the compressor there 55
may
be
adjustably
varied.
'
55
The bell crank E56 is also provided with an will be a similar increase in the pressure of the
arm I66 through which extends a plunger I66 fluid in the chamber I44 on the face oi the dia
which is slidably mounted in a bore in the casing phragm I42, and a correspondingincrease in the
section I30. A spring I10 is mounted on the force exerted on the diaphragm I42 in opposition
plunger
I66 and extends between a ?ange I12 on to the spring I60, whichoperates through the arm 60
60
the plunger I66 and a face of the arm I66 of the . I54 ofrthe bell crank I56 and the plunger I48. _
As the pressure of the ?uid in the chamber I44
bell crank I56.
_
The plunger I66 also has secured thereon a increases the diaphragm I42 will be moved to the
washer I14 which is held by means. of'a cotter left, as viewed in Fig. 7 of the drawings, thereby
phere.
An end of the plunger I48 engages an arm I56
65 pin I16 and which limits movement of the plun
ger I63 by the spring I10;
.
‘ '
.
The spring H0 is under initial compmsion
and holds the washer I14 in engagement with
rounded projections I13 on the lower face of the
70 arm I66 of the bell crank I66, and the'v‘arious
parts oi’ the apparatus .arearranged and propor
' tioned so that when the washer -I‘_|4"is in engage
ment with the projection I13,a_n’d when the arm
moving the plunger I46, and its movement will 65
' be transmitted to the arm I54 of the bell crank
I 56, causing the bell crank to be moved in a clock
wise direction about the pin I56. ,On this move
ment of the arm I64 the tension on the spring
I60 is increased, while the arm I66 presses ‘against
the spring I10 and moves the plunger I63 up
wardly.
'
'_
to
‘
After a slight initial upward movement of the
"I54,is in engagementwith the stop_'"l65,- the end . plunger I63 it engages the face of the piston I33
of the plunger I33 will‘ notextendinto the bore so that on further upward movement of the arm» 15
6
2,185,248
I66 of the bell crank I56 the spring I10 is com
pressed, and during this period the spring I10
opposes movement of the bell crank I56 by the
the passages 2I0 and 2I2 against the bridging
value the force exerted by the ?uid under pres
the'spring side of the piston I80, and therefrom through the passage I92 to the chamber I38 lead
ing to the’ compressor intake passage, as long as
the compressor continues to operate. As a result 10
of the ?ow of ?uid from the chamber 208 air will
continue-to ?ow from the atmosphere through
the passages 2_I0 and 2I2 so that the air blast
contact I96 and cools and thereby helps to inter
rupt the arcs which form between the bridging
contact and the stationary contacts.
?uid under pressure in the chamber I44.
_
Fluid will continue to flow from the chamber
When the pressure of the ?uid compressed by
the compressor is increased to a. predetermined 208 through the passage 2I4 to the chamber I90 on
sure in the chamber I44 is sumcient to move the
diaphragm I42 against the combined opposition
10 of the springs I60 and I10 and the valve I50 will
be moved adjacent the seat rib I52. As the com
pressor is being operatedat this time air is con
tinuaily drawn into the chamber I40 past the seat
rib I52, and when the valveI50 is moved adja
15 cent to the seat rib ‘I52 so as to substantially re
- strict the rate of ?ow of ?uid past the seat rib I52
a relatively high' vacuum will be created in the
chamber I 40.
On this reduction in the pressure of the ?uid
20 in the chamber I40 the effective pressure of the
?uid in the chamber I 44 on the opposite side of
‘ the diaphragm I42 will be increased, and there
will be a corresponding increase in the force
exerted bythe ?uid in the chamber I44 on the
26. diaphragm I42 and tending to move the plunger
I48 against the combined opposition of the springs
which serves to extinguish the arcs formed on the
interruption of the circuit to the driving motor 15
and to cool the contacts continues to ?ow as
long as the compressor continues to operate.
‘On movement'of the piston I80 against the
spring I88 substantially to the end of the vbore
in which the piston I80 is mounted, the piston 20
moves to a- position in which the groove I86 is
in alignment with the end of the stem I68 so
that the stem I68 is forced into the groove I86
by the spring I10. This serves to lock the piston
I80‘ and to prevent its return by the spring I88 25
when the‘ compressor ceases to operate and the
pressure of the ?uid in the compressor inlet pas
>
As a result of this increase in the force exerted sage is restored to atmospheric pressure by the ’
by the ?uid under pressure in the chamber I44 ‘ ?ow of air thereto through the passage 2I_4 and
30
the plunger I48 will be rapidly moved against the the passage I92, or by other means.
On movement of the plunger I68 into the
springs I60 and I10 and will move the valve I50
into engagement with the seat rib I52 so as to groove I86 the spring I10 expands somewhat,
prevent the supply of ?uid under pressure from thereby reducing the force exerted by this spring
_ the atmosphere to the chamber I40 and thence on the arm I66 of the bell crank I56, and re
ducing the force tending to move the plunger I48
‘
35 to the compressor intake passage.
As a result of this movement of the plunger I48 against the opposing force of the ?uid under
the bell crank I56 will be moved in a clockwise pressure in the chamber I44.
After the compressor ceases to be driven by
direction and the compression of the spring I10
I60 and I10.
will be increased, thereby pressing the plunger I68
more firmly‘ against the face of the piston I80.
On the establishment of a relatively high de
gree of vacuum in the compressor intake passage
?uid ?ows thereto from the chamber I90 on the
the driving motor air from the atmosphere ?ows
to the chamber 208 and therefrom by way of the
passage 2I4, the chamber I90, and the passage
I92 to the chamber ‘I38 which communicates with
the compressor intake passage.
40'
The pressure of v
spring side of the piston I80 through the passage
45 I92, assuming that the valve I94 is in the open
position, thereby reducing the pressure in the
the ?uid‘in the chamber I38, therefore, and also
in the chamber I40, will be gradually restored to
atmospheric pressure.
chamber I90. On a reduction in the pressure of
the ?uid in the chamber I90 ?uid ?ows thereto
On an increase in the pressure of the ?uid in
the chamber I40 to atmospheric pressure, there
from the chamber 208 through the'passage 2I4, is an increase in the force exerted by this ?uid
on the diaphragm I42 in opposition to the force 50
thus reducing the pressure of ?uid in the cham
50
exerted by the ?uid in the chamber I44 and
ber 208. The rate of ?ow of ?uid from the cham
ber 208 through the passage 2I4 is substantially tending to maintain the control device in the
‘less rapid than the rate of ?ow of ?uid from the. condition to interrupt the circuit to the compres
.
chamber I90 through the passage I92 to the sor driving motor.
The various parts of the control device are ar 55
chamber
I38,
and
hence
the
pressure
of
the
?uid
55
in the‘chamber I90 will be reduced substantially ranged and proportioned, however, so that the
below that in the chamber 208.
y
'
‘As a result of the reduction in the pressure of
.the ?uid in the chamber I90v the piston I80 will
be moved by the ?uid in the chamber 208 against
the spring I88.
) A On this movement of the piston I80 the bridg
increase in force resulting from this increase in .
the pressure of the ?uid in thechamber I40
and opposing the force exerted by the ?uid in
the chamber I44, is of lesser magnitude than the 00
reduction in force opposing the force exerted
by the ?uid under pressure in the chamber I44
which occurs as a result of the expansion of the
ing contact I96 is moved away from. the contact
ing faces of the stationary contacts I98 and 200, . spring I10 when‘the plunger I68 is pressed into
65
thereby interrupting the circuit to the compressor the groove. I 86 in the piston I80.
As a result of these changes in the various
driving motor. On movement of the bridging
contact I96 away from the contacts I98 and 200 forces operative in the control device, there is
arcs form between the bridging contact I96 and an increase in the force effective to maintain the
control-device in the condition to interrupt oper
the stationary contacts.
'
'
.
70
70 On movement 01’ ‘the piston I80 against the ation of the driving motor for the compressor.
On a reduction in the pressure of the ?uid in
springyl88 the volume of the chamber 208 is in-'
creased, thereby further reducing the pressure of the reservoir associated with the compressor con
trolled by this control device there will be a
the ?uid in this chamber. As a result of the re
corresponding ‘reduction in the pressure of the
duction in the pressure of the ?uid in the cham
ber 208 air from the atmosphere ?ows through ?uid in the chamber I44, and a similar reduction 75
"us
2,136,248
,
.
-
v
7
on the completion‘oi’ the circuit to the cam
will result in the force exerted by this ?uid on
the diaphragm I42 and on the plunger I‘48 in op ~pressor driving motor the motor operates to drive
the compressor and causes it to‘ compress v?uid
position to the springs I68 and I18.
However, because of the reduction in the degree into the.reservoir"associated therewith. The
of compression- of the spring I18‘ 'as-a result of compressor continues to operate'until the pres- 5
movement of the plunger I68 into the groove I86 sure of the ?uid in this reservoir ‘has increased
in the piston I88, the springs I18 and I6v8'will to the value which is e?’ective to cause the con
not exert enough force on the plunger I48 to trol device to again operate as described‘ in de
move it against the opposing force of the ?uid tail above to unload the compressor and to in- .
terrupt the circuit to the driving motor.
10
10 under pressure in‘ the chamber I44 until a pre
This control device incorporates 1 means to.
determined reduction in the pressure of the ?uid
condition it to ‘permit continuous operation ‘of
in the chamber I44 has taken place.
the compressor driving motor if desired, and to
On this predetermined reduction in the pres
effect only unloading of the compressor on an
sure of the ?uid in the chamber I44 the springs
increase to a predetermined value in the pres- 15
15 I68 and I18 operating through the bell crank I56
will move the plunger I48, and the diaphragm ‘sure of the, ?uid compressed by the compressor
I42 against the opposing force of the ?uid under and to maintain the compressor unloaded until
pressure in the chamber I44.
,
-
the pressure of the ?uid compressed by the com
I
pressor has decreased to a lower predetermined
On this movement of the plunger I46 the valve
20 I58 is moved away from the seat rib I62, thereby
value.
'
20
If this method of operation is. desired the valve
I84 is turned to the seated position to cut’o?f
again establishing communication from the at
mosphere to the chamber I48, from which fluid
communication between the chamber I38 and
flows to the compressor intake passage.
After a- certain amount of movement of the
the chamber I88 on the spring side of the piston _
I88. With the control device conditioned for 25
this method of operation the piston I68 is main
v~tained bythe spring I68 in the position in which
the contact I96 engages the stationary contacts
25 arm I66 of the bell crank I56 the projection I18
engages the washer I14 so that on further move
ment of the bell crank I55 the plunger I68 is
moved away from the piston I88.
When the spring I18 has expanded to a degree I I98 and 288 to complete the circuit to thelcom
pressor driving motor.
.
'
30 sumcient to press the projections I18 against the
The compressor will be driven by ‘the driving
‘washer I14, this spring thereafter does not exert
any force on the bell crank I56, and tending to motor, therefore, and, on an increase in the
30
move it against the opposing force of the ?uid ' pressure of the ?uid compressed by the com
under pressure in the chamber I44 on the face ~ pressor to a predetermined value the pressure
of the diaphragm I42.
._ of the ?uid in the chamber I44 will exert ,a force. 35
,
The bell crank I56, therefore, will be urged 3 on the diaphragm I42 su?lcient'to move the dia-_
in the direction to move the plunger I68 away phragm I42 and the plunger I48 to the left, as
from the piston I88 only by the spring I68‘ and viewed in Fig. 7 of the drawings, thereby mov- ''
the force exerted by this spring will gradually ing the bell crank I55.
, {0n initial movement of the bell crank I56 the 40v
40 decrease as the arm I54 is moved towards the
plunger I 8 is mov‘ed’into engagement with the ' ' '
stop I65 and the tension on the spring I68 is ’
reduced.
piston. I8 so that on further movement of the
'
bell crank the spring I18 is compressed, while
this movement of the bell ‘crank I56 is opposed
Because of this gradual decrease in the force
exerted by the spring I 68 the ?uid in the ‘cham
ber I44 must reduce to a somewhat lower, value
before the bell crank I56 is moved to the posi
tion to move the 'plunger I68 to unlock ‘the pis
by the spring I68.
' 4'5
'
On a predetermined increase in the pressure
of the ?uid in the chamber I 44 the plunger I48
will be moved far enough against the springs I68
ton' I88 than was required to move the plunger
and I18 to move the valve‘i58 adjacent to the
I48 against the spring I68 to the position in
which the valve restricted the flow of ,air past
‘
seat rib I52. As the compressor is being oper- 50
ated at this time air is drawn into the chamber
I48 from‘ the atmosphere and ?ows therefrom
the seat rib I52 to a substantial extent. This
is true as the parts of the control device are
arranged so that the plunger I68 does not re a to the compressor intake passage.
When the
?ow of ?uid to the chamber I48 from the atmosf
I
I
phere is restricted by movement of the valve I58 55 ‘r ' -
lease thepiston I88 until the bell crank i66
is moved substantially into engagement with the _
stop I65, while the valve I58 does-not greatly re- ’ adjacent to the seat rib I 52 a partial vacuum
will be created in the chamber I48.
strict the ?ow oi’ ?uid past the seat rib I52 until
of the ?uid under pressure in the chamber I54
acting on the diaphragm I42. The diaphragm
I42 will thereupon be rapidlymoved to the left,
1 I44 has reduced to a predetermined value the‘
as viewed in "Fig. 7, and will move the stem I68 '
bell crank I56 is moved into engagement with
the stop I65, while the plunger' I68 is moved.
‘out of the path oi’ movement of the piston I88;
thereby releasing the piston, with'the result that
the spring I68 moves the piston to the vleft, as
to the left, thereby moving the valve I58 into 65
engagement with the seat rib I52 to cut oil’ the .
?ow of air from the atmosphere to the chamber -
I48 which communicates with the compressor
viewed in Fig. '1, ‘in the bore in the casing I88. .
.
.
On' this movement 01' the piston I68 the bridge
.
- ing contact I66 moves into engagement with the
75
'
the face of the diaphragm I42 opposite ‘frcmthe
_ .
chamber I 44 and will increase the effective force 00 '
from the stop I65.
when the pressure of the ?uid in the chamber
70
~
This will reduce the pressure of the ?uid on
it has been moved towards the seat rib an amount
sufficient to cause the arm‘ I54 of the bell crank
80 I56 to be moved a substantial distance away
inlet
_
passage.
.
-
'
.
1
.
As communication between the chamber ' I38 "0 ' '
and the chamber I68 on the spring side or the
piston. I88 through the passage I82 is cutoff _
stationary contacts I68 and 288,v thereby com
pleting the circuit between these contacts and
establishing a circuit to the driving motor or the
mains in the position to maintain the means 1
compressor.
contact _I86.in engagement with, the. stationary 7 ‘
a
Y
by the valve I84 atthis time-the piston I“. re
8
2,186,248
contacts I98 and 200 and thereby continue to
cause the driving motor to drive the compressor. '
As the compressor continues to be driven by
I the driving motor, and as the valve I50 is main
Ul tained in engagement with the seat rib I52, a
relatively high degree of vacuum will be present
in the chamber I40 and in the other passages
associated with the compressor intake passage,
and this relatively high degree of vacuum oper
ating upon the differential areas of the dia
phragm I42 and the face of the valve I50 within
the seat rib I52 increases the effective force of
the ?uid under pressure in the chamber~ I44
operating on the diaphragm I42 and tending to
maintain the plunger I48 in the position to un
load the compressor.
I
On a reduction in the'"pressure of the ?uid
‘ inthe reservoir associated with the compressor
'
I60 the compressor will be unloaded in response
to a somewhat lower pressure in the reservoir as
sociated therewith.
In Figs. 2, 3, 8 and 9 of the drawings I have '
illustrated a, form of control device embodying
this invention and adapted for use in connection
with a compressor driven by an internal com
bustion engine.
As shown in Fig. 2 of the drawings there is av
compressor 200, which may be of any suitable
well known’ construction and is driven by means
of an internal combustion engine 20I, which'may
also be of any suitable well known construc
tion;
‘
The engine 20I is provided 'with an intake 15
manifold 203 having a fuel supply device in the 7
form of a carburetor 205 associated therewith.
The carburetor 205 includes a throttle valve 208,
which controls the supply of fuel from the‘ car
controlled by this control device there will be
a corresponding reduction in the pressure of buretor to the engine, and this throttle valve 20
is controlled by means of a lever 2I0 which is
the ?uid in the chamber I44, and a similar re
duction in the force exerted by the ?uid in this connected by means of a link-2I2 with. a piston
chamber onnthe diaphragm I42 and tending to 2I4 mounted in a bore of a control device 2I6.
The piston 2“ of the control device 2I6 is
maintain the plunger I48 in the position to un
yieldingly urged by means of a spring 2I8 in 25
_
'25 load the compressor.
Because of the partial vacuum in the chamber the direction to move the throttle valve 208 to
I40 the pressure of the ?uid in the chamber I44 the open or engine load position.
The compressor as shown in Fig. 2 of the'
on the face of the diaphragm I42 mustreduce
to a somewhat lower value than is effective to
30 move the plunger I48 to the position to unload
the compressor before the springs I60 and I10
will be able to‘ overcome the forces tending to
maintain the plunger I48 in the position to un
drawings has a control device indicated gener
ally by the reference numeral 220 associated .
therewith, and operative in response to varia
tions in the pressure of the-?uid compressed by
the compressor to control the supply of ?uid un
der pressure to and the withdrawal of fluid from
load the compressor.
_
However, when this reduction in the pressure the control device 2I6 and thereby control the 35
of the ?uid in the chamber I44 has taken place position of the throttle valve 208 of the engine.
the springs I60 and I10 operating through the 20I.
bell crank I56 move the plunger I48 against the > .The construction of the control device 220 is
opposing force of the ?uid under pressure in the best shown in Figs. 8 and 9 of the drawings, and
as shown in Fig. 8 of the drawings, the control 40
40 chamber I44 acting on the diaphragm I42, device 220 comprises a hollow body 222 having
thereby moving the valve I50 away from the
seat rib I52.
_
I
a passage extending therethrough in which is
On movement of the valve I50 away from the
seat rib I52 air from the at nosphere ?ows past
the seat rib I52 to the chamber I40 and increases
interposed suitable air straining material, such
which the ?uid is compressed by the compres
, round projections 250 carried by arms 252 which
as curled hair indicated at 224, which is con
?ned between perforated plates, one of which is 45
the pressure of the ?uid in this chamber. . This indicated at 226.
The passage through the body 222 communi- 1”
increases the pressure on the face of the dia- phragm I42 and decreases the effective force of cates with an opening in a mounting face on the
the ?uid under pressure in the chamber I44 on body which is adapted to be secured against a
similar mounting face on the compressor 200 sur 50
the opposite side of the diaphragm I42.
As a result, therefore, the springs I60 and H0 rounding the compressor intake passage 22.8.
The control device 220 includes, in addition,
will thereupon rapidly move the plunger I48 to
the right, as viewed in Fig. '7 of the drawings, a movable abutment in the form of 'a diaphragm '
230 which .is subject on one side to the pressure
until the bell crank I56 has been moved into en
of the ?uid in a chamber 232 which communi 55
gagement with the stop I65. ~
.
.
v
cates by way of a choke 234 and a pipe 236 with
The compressor is now unloaded and as it con
tinues to be driven by the driving motor it will the reservoir 238 into which the compressor com
compress ?uid under pressure into the reservoir presses ?uid.
The diaphragm 230 has secured thereto a hol
associated therewith, and will continue to do so
until the pressure of the ?uid in this reservoir ,2 low stem 240 which is adapted to engage a stop 60
has increased to a value sufficient to cause the 242 to limit movement of the diaphragm 230 and
control device to again operate as described in the stem 240 in one direction. '
The stem 240 has an opening extending there- _
detail above to unload the compressor.
‘This control device incorporates means by through in which is mounted a valve 244 which
is urged to the seated position by means of a 65
which the pressure to which the device is re
sponsive to effect- unloading of the compressor‘ "spring 246 mounted in a bore in. the stem 240
and extending between a shoulder on the stem
maybe adjustably varied if desired. This is ac
complished by turning the nut I64 on the eye 240 and a spring seat 248 which is secured on, the
I62, thereby varying the tension on the" spring valve 244._
The stem 240 has an annular recess formed 70
70 I60. If the nut I64 is turned so as to increase therein and adapted to receive substantially
the tension on the spring I60 the pressure to
sor must build up before the compressorwwill be are pivotally supported on a pin 254 and which I
unloaded is increased, while if the nut turned have their free ends joined by means of a mem
75 in a direction to reduce-the tension on the spring ber 266. One end of a spring 258 is connected
2,186,248
to the member 256 and the other end ofthis
spring is connected 'to an eye 268 which extends
through an opening in the body of the control
device and has a knurled nut 262 secured on the
end
thereof.
v
_
-
.
9
moved closely adjacent thereto is relatively small
so that the valve may move relative to the stem
248 to the seated position without the head por
tion of the valve 266 engaging the enlarged head
- 286 on'the valve 244.
The control device 228 has associated there.
with a valve 266 having a head which is slidably
mounted on the end of the stem 248, and hav
ing a tubular guide'portion 268 which is 'slld
ably mounted in a bore in the body of the con
trol device. The head of the valve 266 carries
a sealing gasket 218v which is adapted to engage
a seat rib 212 to cut off communication between
the atmosphere and a passage 214 leading to the
compressor intake passage. The passage 214 is
connected by way of a pipe 216 with a chamber
218 in the control device 2|6.
'
Because of the difference in the pressure of
the ?uid on opposite sides of the valve 266 a
force will be exerted on this valve tending to
move it to the seated position or to hold it in
the seated. position after movement thereto 10
against the opposing force of the spring 288. The
force exerted by the spring 288, therefore, on
the stem 248 to oppose movement of this stem
by the fluid under pressure in the chamber 232
acting on the diaphragm 238 is accordingly re
duced. Because‘ of this reduction in the force
exerted on the stem 248 in opposition to the
?uid under pressure in the chamber 232, on move
ment of the valve 266 to the seated position the
stem 248 will thereafter be moved very rapidly
by the ?uid under pressure in the chamber 232
and will press against the valve 266 and hold
284 within the tubular portion 268 and the pas- ' the sealing gasket 218 in engagement with the
The valve 266 is yieldingly urged away from
the seat rib 212 by means of a coil spring 268,
while the tubular portion 268 of the valve 266
has a restricted opening 282 therethrough so as
to establish communication with the chamber
sage .214.
'
seat rib 212.
The end of the valve 244 carried by the stem
248 is provided with. an enlarged head 286, which
is adapted to be engaged by a portion of the
head of the valve 266, as will hereinafter more
fully appear.
~
-
i
'
The chamber 284 within the tubular. portion
of the valve 266 communicates with the passage
214 by way of the restricted passage 282, and on -
a reduction in the pressure of ?uid in the cham
This control device is shown in Fig. 8 of the
drawings in the position to effect loading of the
compressor, to condition the fuel supply device
associated with the engine for driving the com
pressor to supply fuel to the engine at the maxi
ber 214 ?uid ?ows thereto from the chamber 284
through therestricted passage 282. This results
in a reduction in the pressure of the ?uid in the
chamber 284 and increases thearea of the valve
266 which is subject to the opposing pressures of
the atmosphere and of the partial vacuum in the
mum rate, and with the pressure of' the ?uid
compressed by the compressor below the pressure
passages associated with the compressor intake
passage and increases the force effective to hold
to which the control device is ‘adapted to respond
to unload-the compressor and to restrict the
supply of fuel to the engine for driving the com
the valve 266 in the seated position.
The various parts of the control device are
proportioned so that when the valve 266 is moved
to the seated position, and the ?uid in the cham 40
ber 284 within the tubularrpolrtion 268 of the
valve 266 is reduced substantially‘ to the same
pressure as the ?uid in the-passage 214,v the force
exerted by the higher atmospheric pressure on
the‘ exposed face of the valve 266 and opposing 45
the spring 288 exceeds by a substantial amount
the force exerted on the valve 266 by the spring
288.
As the compressor continues to be operated
by the driving motor a relatively high degree of 50
vacuum will be .present in the compressor intake
pressor.
-
_
On an increase in the pressure of the ?uid in
the reservoir 238 there will be a similar increase
in the pressure of the ?uid in the chamber 232
and a corresponding increase in the force ex
erted by this ?uid on the diaphragm 238. Move
ment of the diaphragm 238 is opposed at this
time by the spring 258 acting through the arms
252 and the projections 258 which engage the
stem 248, and also by the spring 288 which op
poses movement of the valve 266 to the closed
position.
'
As the pressure of the ?uid m the chamber 232 '
increases, however, the force exerted on the
diaphragm 238 will increase, and‘ when the pres
sure of the ?uid in the chamber 232 has in
creased to a predetermined value the force ex-~
erted on the diaphragm 238 will be sufficient to
overcome the opposing forces of the springs 258
and 288. The diaphragm 238 and the stem 248
will thereupon be moved and the valve 266 will
be moved towards the seat rib 212. _
As the compressor is being operated at this
time there is a rapid ?ow 'of- air from the at
mosphere past the .seat rib 212 to' the passage
214 and thence to the intake passage 2280f the
compressor. When the valve 266 is moved adja
cent to the seat rib 212 so as to restrict the ?ow‘
of air from the atmosphere to the passage 214,
a partial vacuum will be formetl in the passage
passage and also in the passages communicating
therewith ‘and air will be drawn through the pipe
216 from the chamber 218 of the control device
2l6.
'
~
1
'
On a reduction _in the pressure of the ?uid in
55
the chamber 218 the higher atmospheric pressure
on the opposite side of the piston 2“ moves the
piston 214 against the spring 218 and this move
ment of the piston 2M is transmitted through 60
the link M2 to the lever 2l8 which operates the
throttle valve 288.
'
On this movement of the piston 2“ the throt
tle valve 288 is moved from the engine load posi- >
tion, in‘which position‘fuel is permitted to be
supplied to the engine .at substantially the max
imum rate, to the engine idling position, in which
the supply of fuel to the engine is substantially
restricted.
This results in a reduction in‘ the
218, and the higher air pressure operating on
speed of the engine and of the compressor, but
the opposite side of the vgve 266 will assist
the compressor continues to be driven at a speed
70'
movement of the valvel266\ihto engagementwith' 'high enough to cause a relatively high degree
the seat rib 212.
.
The distance which the valve 266 has to be
moved in moving to its seat after having been
of vacuum to be maintained in the compressor
intake passages and in the associated passages.
It will be seen, therefore, upon operation of 75
10
2,185,248
the unloading means to effect unloading of the
tending to maintain the valve 288 against the
compressor the fuel supply to the engine for driv
seat'rib 212. The valve 288 may be moved away ‘
ing the compressor is restricted. -
from the seat rib 212 at this time by the spring
288. If, however, the valve isnot moved .away
from the seat rib by the spring 288, on further? 5
movement of the stem 248 to the right, as viewed
in Fig. 8 of the drawings, the end of the stern 248
As ‘the restriction in the supply of fuel to the
engine does not take place until'the compressor
has been unloaded there is no danger of ‘the
engine being stalled as a result of being over
loaded. As the restriction in the supply of fuel engages the spring. seat 248, so as to move the
to the engine takes‘ place immediatelyupon op ' valve 244 to the right, and on this movement of
10 eration of the unloading means there is no danger ' the valve 244 the head 288 presses against the
either that the engine will race or overspeed ' head of the valve 288 and moves it away from the
seat rib 212.
'
,
because of an excess supply of fuel thereto.
on movement of the valve 288 away from th
On a reduction in the pressure of the ?uid in the
reservoir 238 there will be a similar reduction in seat rib 212, air from the atmosphere ?ows past
15 the pressure of the ?uidin the chamber 232, and the seatn'ib 212 to the passage 214, thereby in
a corresponding reduction in‘ the force exerted. creasing the pressure of the ?uid in the passage
214. On this increase in the pressure of the ?uid
by this ?uid on the diaphragm 238.
‘ ' As pointed out above the spring 288 is ine?eee in the passage 214 there is a reduction in' the
’ tive to urge the stem 248 against the ?uid in the forces tending to hold‘ the valve 288.in th'e'seated
20 chamber 232 at this time as the valve 288 is held position, and the‘valve 288 will thereafter be
moved very rapidly to the full open- position by
in engagementwith the seat rib 212 by atmos
. a
>
pheric pressure acting on the exposed face of the spring 288.
On an increase in the pressure of the‘ ?uid in
the valve. The stem 248, therefore, is subject to
the cha ber 214 as a result of opening of the
the opposing pressures'of the ?uid in the cham
25 ber 232 and of the spring 258, and the stemi248
will not be moved by the spring 258 until the
~ pressure of the ?uid .in the chamber 232 has
18V ,
valve 28 ?uid ?ows therefrom by way of the
pipe 216 to the chamber 218 of the control de-'
vice 216, and on an increase in the pressure of '
reduced to a value such that the. force exerted the ?uid in this chamber the spring 2l8- moves
by this ?uid is less than the force exerted on the the piston 2“ to the right, as viewed in Fig. 3
30 stern 248 by the spring 258. This pressure will ' of the drawings, and‘ this movement of the pis
be somewhat less than the pressure required to ton 2“ is transmitted through the link 2l2 to
‘effect movement of the stem 248 to unload the the arm H8 and movesvthis arm so as to move
compressor as this movement of the stem 248 is the throttle valve 288 from the engine idling po
opposed by the spring, 288 in addition to the
sition to the engine load-position.
The compressor is now in the loaded condition,
when the pressure of the ?uid in the chamber while the engine is supplied with fuel at a rapid _'
232 is reduced a predetermined low value such rate so as to drive the compressor and cause it to
that the force exerted on the stem 248 by the compress fluid into the reservoir 238. The com‘
spring 258 exceeds the opposing, force of the pressor will continue to operate and to‘ compress
.?uid into the reservoir 238 until the pressure of
40 ?uid‘ under pressure acting on the diaphragm
238 and thereby on the stem 248, the stem 248 the ?uid in'this reservoir has increased to the
will be moved to the right, as viewed in Fig. 8 ' value which is effective to cause the control de- of the drawings,- by the spring 288 acting through vice to again operate as described in detail above
' to _unload the compressor and to restrict the
the arms 282 and projections 258.
After-a predetermined amount of movement supply of fuel to the engine for driving the com 45
spring 258.
"
v
,
y
' of the stem 248,the head 288 von the valve 244 .
engages the head of the valve 288 and on fur
ther movement 'of the stem 248 the valve 244 is
moved away from its seat against the spring 248.
On movement of the valve 244 away from its
- seat the ?uid under pressure present in the cham
her 282 is permitted to escape therefrom at a
pressor.
"
_
This-form of compressor control device incor
porates means by which the pressure to which
the device responds to unload the compressor
and to reduce the supply of fuel to the engine
may be adjustably varied if desired. This is ac
complished by'turning the knurled nut 282 so as _
rapid rate through the passage in-the stem 248
to vary the tension on the spring 258.
in which the valve 244 is loc'ated to the chamber
If the tension of the spring 288 is increased
284 within the tubular portion 288 of the valve the pressure of the ?uid in the reservoir 238 and
288. This increases the pressure of the ?uid in ' in .the chamber 232 must increase to a higher
the chamber 284 and reduces the force tending value before the force exerted on the diaphragm
to hold the valve 288 in engagement with the 238 exceeds the force exerted by the springs 288
seat rib 212,v
.
y _
and 288 and opposing movement of the stem 248
On movement of the valve 244 away from its vto the position to condition the control device to
seat ?uid under pressure ?ows from the chamber unload the compressor.
232 to the chamber \284 at a rapidrate, while
Similarly, if. the tension on the spring 288 is I
?uid is permitted to'?ow to the chamber 232
force exerted by the ?uid under
from the reservoir 238 by way of the pipe 238 and decreasedin’the
the chamber 232 on the diaphragm
through the choke 284 onlyat a restricted‘rate. pressure
'There will, therefore, be a rapid reduction in 238 will exceed the opposing force oi’ the springs
the pressure of the ?uid in the chamber 232 as 288 and 288 on an increase in the pressure of the
soon as the valve 244 is opened, and on this‘ re
duction in the pressure of'the ?uid in the cham
70 ber 232 there will vbe a corresponding decrease in
the force exerted on the diaphragm 288 and the
spring 258 will thereupon rapidly move the stem
248 to the right until it ‘engages the stop 242.
On the supply of ?uid under pressure to the
is
chamber 284 there is a reduction in the force
?uid in the chamber 232 to a somewhat lower
value than before.
It will beseen that this form of compressor '70.
control device incorporates means responsive to
the pressure of the ?uid compressed by the com
pressor for effecting loading and unloading of the,
means
compressor,‘
responsive
and that
to operation
it includes,
of‘the
in unloading
addition, .1
v11
2,18/6,248
means vfor controlling the means for driving the ~ sage and
compressor.
-
While several embodiments oi’ the'improved
compressor control means provided by this in
5‘ vention have been illustrated and described in
detail it should be understood that the invention
controlling the driving means, said
means comprising a control member movable be
tween a cut~in position in which the driving
means is conditioned to drive the compressor and
a‘ cut-out position in which the driving means
is conditioned not to drive the compressor, an
is not limited to these details of construction. abutment subject to andv operated on a'prede- . ‘
and' that numerous changes and modi?cations I termined increase in the pressure ofv the. ?uid
may be made without departing from the scope compressed by the compressor for operating the
10 of the following claims.
‘
valve'means to cut off the ‘supply of ?uid to the
Having nowydescribed my invention, what I . intake passage, and latch means associated with
claim as new and desire to secure by vLetters said abutment. and operative on movement of
Patent, is:
' ‘
'
the abutment to condition the valve means to
— 1. In. combination, a ?uid compressor having cut oil’ the ?ow of ?uid to the intake passage to
I 15 an intake passage through which ?uid is supplied permit the control member to move to the cut 15
_ to‘ the compressor, valve means controlling the
supply of, ?uid to said intake passagadriving
out position and on movement of the control
member, to the cut-out position to ‘prevent move
'means for the compressor, meansresponsive to > ment thereof to the cut-in position. ,
the pressure of the ?uid in said intake passage
20 and controlling the driving means, said means
comprising a control member movable between
a cut-in position in which the driving means is
conditioned to drive the compressor and a cut
'
‘
3. In combination, a .?uid compressor having
an intake passage, valve means controlling the 20
?ow of ?uid to said intake passage, an electric
motor for driving the compressor, apair of rela
tively movable contacts controlling the supply
out position in which the driving means is con- ' or current to the driving motor, said contacts
25 ditioned not to drive the compressor, an abut
ment subject to and operated on a predetermined
increase in the pressure of‘ the-?uid compressed
by the compressor for operating the valve means
to cut ed the supply of ?uid to the intake pas
30 sage, and‘latch means associated with said abut
ment for maintaining the control member in the
cut-out position.
‘
' '
being mounted in a chamber having communi '25
cation with the compressor intake passage,
means operated on a predetermined increase in
the pressure of the?uid compressed by the com
pressor for closing said valve means and for
thereafter e?’ecting separation --of said contacts
and thereby interrupting the supply of‘ current
to the driving motor, and means operative on a
2. In combination, \a ?uid compressor having‘ reduction in the pressure of the ?uid in said
an intake passage through which ?uid is sup
> '5 plied to the compressor, valve means controlling
‘
the supply of ?uid to said intake passage, driv- '
ing means for the compressor, means responsive
, to the pressure of the ?uid in (said intake pas- -
chamber to a pressure below atmosphere for
creating a '?ow 01’ air in the region between said
contacts.
'
,
BURTON
.
AIm/IAN.
30
~
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