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Патент USA US2406202

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Patented Aug. 20, 1946
i 2,406,202
UNITED STATES PATENT> OFFICE j
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AIR
Y COMPRESSOR
2,406,262
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Phil-ip L. Crittenden, Edgewood, Pa., assìgnor to4
The Westinghouse Air Brake Company, Wil
merding, Pa., a corporation of Pennsylvania
Application December 28, 1943, Serial No. A515,92€)
1o claims.
This invention relates to fiuid compressors and
more particularly to: the reciprocating piston
type.
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4(o1. 23o-184)
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bottom surface of thehead IIJ', the Wall of the
cylinder 4 and the top surface of the piston. 5.
In a similar manner a, ñuid compressing-cham
In compressors of the conventional type,v it has
ber I2 isv definedV at the left hand endv of the cas
been found necessary _to have a. certain amount
ing by another portion of the bottom surface
of dead space for clearance between the piston
of the head I0, the wall of the cylinder 'If and
and the cylinder head and in the valve chambers.
the top surface of the piston 8.
This space retains a quantity of fluid at a pressure
Formed in the bottom face of the cylinder
substantially above-they fluid pressure of a storage
head
I IJ and located between the two portions> just
reservoir or receiver, whichV iiuid must expand 10
mentioned is a recess I 3 which communicates with
during the intakestroke until the pressure in the Y
the compressing chamber II'by way of a valve
cylinder is substantially below atmospheric pres
controlled passage I4Í in the head and with the
sure before the inlet valve will open to supply
compressing chamber I2 by way of a Valve con
ñuid to» the cylinder for the. inlet stroke. This
trolled passage I5V in the head. This recess is
cond-ition results' in lowered volumetric eiiiciency
open at theV bottom toA a vertical bore IB formed
because of the unproductive piston movement
in the wall between the cylinders 4 and ‘I’ of the
and thediminished quantity of fluid delivered by
casing I.
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the compressor to the receiver.
Slidably mounted in the bore I 6 is a piston valve
It is an object of this invention, therefore, to
provide an improved compressor of the recipro 20 member I'I, the> upper end` of which is provided
with a frusto-conically shaped valve I8. This
cating piston type so designed that thev inlet
valve is arranged to engage a corresponding valve
and discharge valves will be positioned promptly
seat I9 which defines a portion of the recess I3`
for the intake movement of each piston and
and to thereby close communication between pas
thereby to increase the volumetric efficiency of
sages I4 and I 5.> Interposed between and oper
the compressor.
25 atively engaging the bottom of the» bore I6 and
Another object is to provide a "compressor hav
the lower end of the valve member I"I is a» helical
ing a plurality of fluid compressing cylinders in
spring 2Q which constantly exerts an upwardlyl
which one cylinder will be supercharged with a
certain amount of iiuid under pressure from an
other cylinder before the beginning ofv the intake
stroke of the piston in the first' mentioned cylin
der.
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In the accompanying drawing the single' figure
isa vertical sectional view of a fluid compressor
directed force on the valve member.
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Thel lower end of the valve member I'I is pro
vided with an actuating stem 2| which is slid
ably carried in a vertical> bore 22 in the casing
I and extends through bore 23 in the crankcase
2 into> the crankcase chamber 24. Securedto the `
lower’end of the stem 2| by a nut 25 is a cross'
constructed in accordance with this invention.
35 member 26 which projects into the paths of travel
As shown in the drawing, the compressor may
of both pistons so as to be engaged> and moved
comprise a casing, designated by the numeral I„
downwardly
by either piston against the oppas#
having secured to the bottom surface thereof in '
ing pressure of spring 2U.
a suitable manner a crankcase 2 in which there
Atthe extreme right-hand end of the cylinder'
is rotatably mounted the usual driven crankshaftv
head I0 there is formed a discharge chamber 2`I3. The right-hand end of the casing I, as illus
which extends vertically through the' head andy
trated, is provided with a cylinder 4 in which a
is in constant open communication with a ñuid
piston 5 is slidably mounted toy be reciprocated by
discharge pipe 28. Y This chamber is closed at the
thecrankshaft 3-through the medium of the con
necting rod 6. The left-hand end of the casing i) top by a hollow nut member 29 which has screw
threaded engagement withr the cylinder head I-U.
I is provided with, a cylinder 1 in which a- pistony
The nut member is providedA with a vertically cy
8 issimilarly mounted and reciprocated likewise
lindrical sleeve portion 3U which extends intol
through the medium of a connecting rod' 9.
Y the chamber 21 andv which servesl as a guide
l Secured to the top` surface of the casing I byA
and a stop for the discharge valve 3 I .v ‘I'his valve;
bolts or other suitable means is a cylinder head
preferably of the tapered poppet type is
operably
I0- which provides valve controlled inlet and dis
mounted in vthe chamber 21. and controls com»
charge passages for the iîiuidr compressed in a
munication between compressing cl‘iamber> I land
manner hereinafter more fully described.V A fluid
chamber 21.
compressing chamber I I is thus defined at'thev
right hand end' of the casingby a portion of the 55 Projecting fromV the upper surface ofthe 'valve
SI is a vertical guide stem 32 which is slid
2,406,202
unseated position fluid under pressure may flow
from compressing chamber I2 to compressing
chamber II by way of passage I5, recess I3 andY
passage I4 for reasons which will hereinafterV
ably guided in the sleeve portion 30 of the nut
member 21. VInterposed between and operatively
' engaging the nut member 21 and the back sur
face of the valve 3I is a helical spring 3‘3 which,
With the piston positioned '
more fully appear.
when the piston 5 substantially completes its
as just described the inlet and discharge valves
will be in their seating positions as shown.
upwardrstroke, urges the valve downward into
Y sealing engagement with an annular tapered seat
_HUpon rotation of the crankshaft 3„,c0nnect
34 formed in the bottom of thel chamber 21'as>
ing".v rod'B and' thereby ¿piston 5 will'. be moved
illustrat‘ed,` to interrupt the flow of fluid under
upwardly.
In response tothe upward travel of
10
pressure'from the compressing chamber II.
Vthe piston the compressed spring 20 will act to
To the left of the chamber 21 there is formed
’ move the valve member I1 upwardly until valve
I8 again engages valve seat I9 and closes com- l
ingthe cylinder head I0 an inlet chamber 35`
which is in constant communication with a fluid
inlet passage 36 which is in open communication
.
munication between chambers II and I2.
It is preferred that the piston movement re
with an inlet pipe 31. This chamberl is closed 15. quired to permit the valve memberV I1 to -seat be
at the top by a nut member '38 which has screwe ‘ relatively small so 'that there will be little reverse
threaded engagement Iwith the headv I6. The
'fluid flow after'the pressures of fluid Vin the
communication between the bottom of the cham- , ,
two rcompressing chambers have equalized.
ber 35 and the compressing chamber lIl may bev
The piston 5 as it moves upwardly compresses
closed,vas illustrated,"by a valve 39, preferably
therfluid
in the chamber II until the Yupwardly
of the poppet type, which is arranged to seat on
directed'force exertedïfbythe fluid V0n the dis*
a. valve seat> 48 formed »in thelower side of the
charge 'valve 3l un'seats> the VvalveÍaga'inst the
combined
downwardly directedrforce exertedwb'y
'vr-Above the valve 39Ãthe
` head _ I 0 is provided with
the
spring
33 and the fluid Vpressure vwhich may
fa; wall: 4I which defines the bottom ofthe cham 25 be in the discharge pipe 28. With valve'3I'un
herr-.35 andwhich’is provided with an' upwardly
fluid will flow from chamber II into dis
extending Vsleeve portion 4Ia `in which »there is Y seated,
charge-chamber 21and thence into discharge
' slidably mounted the guide vste'm’42 of the lvalve
pipe 28 anda suitable fluid receiver, notV shown.
under pressure will continue to flow in this
,The stem 42 »is preferably formed integrally 30 Fluid
manner
until the piston-5 nearly'reachesrtheend
with the valve 39 and is iluted to permit the pas
of
its
upward
stroke when,V with the ñuid pres
sage of fluid through the sleeve portion 14|.
sures in the discharge pipe 28Íand the chamber
Pinned to the upper end of the stem is a spring
5 substantially'equal, the force of the s'pring33- Y
seatY 43, Vupon- which an upwardly directed force
will prevail and the valve 3I"'Wil1 again be seated. Y Y
35
is exertedby `a spring 44 interposed> between the
At the same time 4aspiston 5 is making its up- Y
spring seat and the upper surface of the wall 4Ia',
ward stroke, piston 8-will be'making its down
'thereby urging the' valve 39 into sealing engage
ward stroke. At the startY of the stroke the inlet
ment with the Valve seat 4I).
and discharge valves are positioned as shown in
-'Attention‘ is here directed to the fact that the
members employed for imparting resiliencyv to 40 the accompanying drawing. After a slight down'
ward movement ofthe piston, pressure> of fluid
the movement of the valves are disposed in the
in chamber l2 will be'sufñciently below atmos
cylinder head and not Vin the compressing cham
phere to allow the pressure of fluid inthe inlet
ber, thereby keeping rthe necessary clearance
chamber 35’ to move valve 39’ against the 'pres
space between the piston and the head at a min
sure of‘spring 44’ and away from the valve seat,Y
imum and thereby'adding to the volumetric efñ
49'. Fluid will flow' through inlet vpipe 31 and
ciencyîofthe compressor.
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passage 36 to inlet chamber 35’ and thence past
¿At the left-hand .end of the compressor, the
the valve-seat ‘49’ to compressing chamber I2.
>head'IILí
39.
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head I_ß is provided with an‘inlet and discharge
valve construction for cooperating with cylinder
The pressure" of ' inñowfing fluid will- hold valve
39' unseat‘eduntil the piston Y8 nears the end of
1 similar‘to that described above for cylinder 4. 50 its
downwardV movement. ` As the' piston'nears
At the extreme left-hand end of the cylinder
the
end of its stroke'the --valve W'ill `aga'inwbe .
head I0, forV controlling the ñow of fluid to and
seated by spring 44’.
from the .compression chamber I2, thereis pro
. ‘Shortly after the inlet valve is seated, thevbot-- ~
vided a; discharge valve mechanism and an inlet
tom
yof the piston 8 will engage the cross-member
valve'mechanism, each of which Yis identicalwith
26
andv
move it downward which will likewise
thercorresponding mechanism mounted in the
move'the ¿valve member Vl1 downward thereby
right-hand end of theA cylinder head. In view
of the similarity; the >several parts of thesemech
moving the valve I8 away from valve seat I9. '
The discharge valve 3I will also- have been
anisms will be indicated by the same reference
numerals a's applied tothe mechanisms atthe
60
right handend of the casing with the exception
that the prime sign is added.
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1 kIn operation, when the crank shaft 3 is lturned
by any suitable source of power, pistons 5 and 8
will be actuated by the connecting rods 6 and 9,
respectively. Each piston completes an inletïand
a discharge stroke for each revolution of the
crankshaft.
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y '.In» the accompanying drawing, piston 6 is
shown in its upper'dead center position and piston
5 is shown in its lower dead center position. ‘TheA
piston 5 in this position acts through the medium
seated before the piston 8 engages the cross-.Í
member 26. Fluid under pressure will now flow
from compressing chamber IIV to compressing
chamber I2 by way of passage I4, recess I3,l and
passage I5.
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The piston 8 will now be at bottom dead center
while the piston 5‘will beat top dead center. f'ïr‘lgleV ` Y
valves will be in the position as illustrated@`>> ~ ;
The same operation will follow as previously
described except that the function performed
by piston 5 will now bel performed4 _bypiston 8
andviceversa»
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At the completion of each compression v_stroke
or inlet stroke, valve member'. l1. will operate to
of the memberl26 and stem 2| of the valve mem
open communication between the two compresse.
ber to hold valve I8 out of engagement with valve
' seat'ßI9. Upon movement of the valve I8 to its 75 ing chambers. /Thu'sthe pressure of Yfluid ina.
5
2,408,202
compression chamber is reduced before the begin
ning of an inlet stroke of its piston and is in
creased before the beginning of a compression
stroke.
Having now described my invention, what I
claim as new and desire to secure by Letters Pat
ent is:
therein while ñuid is being compressed in another
chamber and comprising two fluid compressing
chambers and two pistons for reciprocating in
the respective chambers, in combination, means
for supercharging each of said chambers with
iiuid under pressure, the supercharging means
comprising means rendering the supercharging
l. In a íluid compressor of the type comprising
means ineffective until either piston is substan
two pistons and means connected to said pistons
tially at the end of its inlet stroke and operative
for actuating íirst one and then the other to 10 by the piston as it approaches the end of its
compress fluid, in combination, a communica
inlet stroke to render said supercharging means
tion for permitting fluid to flow between the
eifective.
pressure sides of said pistons, a valve for open
7. A iluid compressor of the type arranged to
ing and closing said communication, means for
draw fluid into one chamber for compression
effecting the operation of said valve to open said 15 while fluid is being compressed in another cham
communication as an incident to either piston
ber and comprising two pistons for reciprocating
reaching substantially the end of its inlet stroke,
in the respective chambers, in combination, means
and means for effecting the operation of the
for preloading the pressure side of a piston, com
valve to close said communication at all other
pleting
its inlet stroke, with fluid under pressure
times.
20 from the pressure side of a, piston completing its
2. In a fluid compressor of the type compris
compression stroke, and means actuable by either
ing two pistons and means connected to said
piston at substantially the end of its inlet stroke
pistons for actuating ñrst one and then the other
to render said preloading means operative, and
to compress fluid, in combination, a communi
means separate from said piston for actuating
cation for permitting fluid to flow between the 25 the second mentioned means to render the pre
pressure sides of said pistons, a valve for open
loading means ineifective.
ing and closing said communication, resilient
8. A fluid compressor of the type arranged to
means for actuating said valve to close said com
draw ñuid into one chamber for compression
munication, and means operative by either of said
while fluid is being compressed in another cham
pistons at substantially the end of its inlet stroke 30 ber
and comprising two pistons for reciprocating
to actuate said valve to open said communica
in the respective chambers, in combination, means
tion.
for preloading the pressure side of a piston, com
3. In a ñuid compressor of the `type compris
pleting
its inlet stroke, with fluid under pres
ing two pistons, and means connected to said pis
sure from the pressure side of a piston complet
tons and operable to actuate first one and then 35
ing its compression stroke, and means condition
the other to compress fluid, in combination, a
able
upon the movement of either piston to sub
communication connecting the pressure sides of
stantially the end of its stroke for rendering said
the two pistons, valve means controlling said
preloading means operative.
communication, and means conditionable upon
9. A ñuid compressor of the type arranged to
the movement of either piston to substantially
draw iluid into a chamber for compression vthere
the end of its inlet stroke to actuate said valve
in while fluid is being compressed in another
means to open said communication, and means
chamber and comprising two fluid compressing
operative to actuate said valve means to close said
chambers and two reciprocating pistons for com
communication at all other times.
pressing ñuid in said chambers, in combination,
4. A fluid compressor comprising two pistons,
means for venting fluid under pressure from one
means connected to said pistons to actuate first
chamber, valve means operative to start and stop
one and then the other of said pistons to com
said venting action, means conditionable upon
press fluid, a communication connecting the
the movement of either piston to substantially
chambers on the pressure sides of the two pis
the end of its inlet stroke to actuate said Valve
tons, valve means controlling said communica 50 means
to start said venting action, and means
tion, means for actuating said valve means to
operative to actuate said valve means to sus
close said communication, and means operative
pend said venting action at all other times.
by each piston at substantially the end of its
10. In a fluid compressor of the type compris
inlet stroke to actuate said valve means to open
ing two pistons and actuating means connected
said communication.
55 to said pistons for compressing fluid with first
5. A ñuid compressor comprising two pistons,
one piston and then the other, in combination, a
means connected to said pistons to actuate first . passage
in open communication with the pres
one and then the other of said pistons to com
sure side of` one of said pistons, a passage in
press fluid, a communication connecting the
open communication with the pressure side of
chambers on the pressure sides of the two pis
the other of said pistons a communication for
tons, valve means controlling said communica
permitting fluid to flow from one of said pas
tion, means conditionable upon movement of
sages
to the other, valve means for controlling
either piston to substantially the end of its in
said communication, resilient means actuating
let stroke to actuate said valve means to open
said valve means to close said communication,
said communication, and means operative to ac
and means operable by either of said pistons at
tuate said valve means to close said communi 65 substantially the end of its inlet stroke to cause
cation at all other times.
said valve means to open said communication.
6. A ñuid compressor of the type arranged to
draw ñuid into one chamber for compression
PHILIP L. CRI'I'TE-NDEN.
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