Note: Descriptions are shown in the official language in which they were submitted.
105;~659 - ::
PRESSURE: RESPONSIVE VALVE STRUCTURE
,
This invention relates to a valve structure whose
operation is controlled, in part, by a reference pressure.
Fluid control valves, of course, have long been
used for a variety of purposes and in a variety of en-
vironments and systems. For example, artific1al kidney
systems typically employ one or more valves to control
the flow of blood from a patient to a dialyzer and then
back to the patient. Such systems generally use a so-called
double-needle cannula to withdraw the blood from the patient
through one needle and return the blood ~o the patient
through th~ other needle. Although single-needle cannulas
have been used in some instances, rather complicated and
cumbersome solenoid valves have been required to control
the flow of blood through the needle so that the blood
alternately flows from the patient through the needle and
then through the needle to the patient. The porta~ility
of such artificial kidney systems, and other systems, could
e enhanced considerably if a more simple lightweight and
compact fluid control valve structure were available.
~'Jj ~
,,~ .
`"i
,~j `
`' '~ .
. ~ . .
. q~
, '
' ' '~' '
.` ' ~.~
,' ... .
,
.' ' ,. . --.
105'~f~59 - 2-
An aim of the invention is to provide a fluid control
valve which is suitable for incorporation into a single-
needle cannula to control the flow of blood therethrough.
In a specific illustrative embodiment of the invention,
S the fluid control valve includes a housing definir.g a
chamber, with the housing having an aperture to enable
, communication between the chamber and a reference pressure
source. First and second ducts extend from the exterior
of the housing to terminate within the chæmber. A diaphragm
is affixed in the chamber between the aperture and the duct
terminations and is moveable to cover the terminations
when the re~erence pressure exceeds the pressure in the
ducts, to thereby p event the flow of fluid from either
duct to the other. When the pressure in the ducts exceeds
the reference pressure, the diaphragm moves away from the
terminations to allow the flow of fluid from either duct
to the other.
In accordance with the invention there is provided
a pressure responsive valve comprising a housing defining
a chamber, said housing having at least one aperture
, therein to enable communication between the chamber and
a reference pressure source, first duct means, one e~ of
:~i
`~ which terminates within said chamber, second duct means,
., ~ .
.. . .
... .
~'
:: .
105~59 3~
one! end of which terminates within said chamber, and
first diaphragm means affixed in said chamber between
said aperture and the terminations of said duct means
and being moveable to cover the terminations when the
reference pressure exceeds the pressure in the ducts
to thereby prevent the flow of fluid from either duct
to the other, and being moveable away from the terminations
when the pressure in the ducts exceeds the reference pressure I -
to thereby allow the flow of fluid from either duct to the
other. The valve of the invention may further comprise
second diaphragm means affixed to the exterior of said
housing over said aperture to prevent communication
between the chamber and the reference pressure source, and
I second diaphragm means may be moveable conjointly with
Sj 15 the first diaphragm means.
. :
, Each of the duct means may terminate a
`~ valve wherein each of said
duct means may terminate in a substantially flat plane,
;~ and the first diaphragm means may include a rigid,
~0 substantially flat portion for contacting and covering
the duct terminations when the reference pressure exceeds
: the pressure in the ducts.
,, .
. ,'J
S
Y . .
..... . .
.`'', ~
.. !
,
, ` ~
. '`,': `' .
iO5'~6S'3 4 _
In an alternate contruction of the pressure responsive
valve in accordance with the invention, the valve comprises
a housing defining a charnber, first diaphragm means affixed
in said chamber ~o divide said chamber into first and second :~
compartments, said housing having at least one aperture
therein to enable communication between the firstcompart- `
~ ment of the chamber and a reference pressure source, first
.~ and second duct means, one end or each of which terminates
within the second compartment of the ch~mber, and said
first diaphragm means including a.stem extendiny therefrom
.' into the second compartment of the chamber, and a plate
affixed on the end of the stem such that when the pressure
in the ducts exceeds the reference pressure, the first
! diaphragm means is caused to move so that the plate covers
.~ 15 the terminations of the ducts to thereby prevent the flow
of fluid from either duct to the other, and when the
1 reference pressure exceeds the p.essure in the ducts, the
first diaphragm means is caused to move the plate away
from the terminations to thereby allow the flow of fluid
. 20 from either duct to the other. As before second duct
~ 'AJ
.. means may be affixed to a valve according to claim 4,
further comprising a second diaphragm means affixed to
the exterior of the housing over said aperture to prevent
i! .
.1 ~ co~rnunication between the chamber and the.reference pressure
.,,-,j
~ !
. . .
:~ "
:
. '
.
-.
lOS~59 ~5~
.
source, and the second diaphragm means may be moveable
conjointly with said first diaphragm means.
i First diaphragm means may include a valve
wherein said diaphragm means includes
a substantially rigid portion to which the stem is attached,
and each of said duct means may terminate in a substantially
flat plane, in which case the plate is substantially flat
for contacting and covering the duct termination when the
duct pressure exceeds the reference pressure.
The invention also provides a combination which is
a combination in a canulla which includes a central tube,
~ one end of which is tapered for insertion into the body
i of a patient. The combination comprises a second tube
7~ branching from the other end of the central tube for
., .
transporting fluid to or from the central tube, and a third
tube branching from the other end of the ~entral tube for
transporting fluid to`or from the central tube, valve means
disposed in said third tube for preventing the flow of fluid
when a reference pressure exceeds the pressure of the fluid
~ in the third tube and for allowing the flow of fluid when
`! .
the pressure of the fluid in the third tube exceeds the
i
reference pressure.
. ',
... . .
~ :3
... . .
;, .
'.'`'
~,;
,
05~59
:`' ..
:
The valve means p--ovided in the above combination may be
' constructed such as is described above. The combination
wherein said valve means comprises a housing
defining a chamber, said housing having at least one
aperture therein to enable communication between the
chamber and a reference pressure source, first duct means,
:, .one end of which terminates within said chamber and the
other end of which communicates with one portion of said
third tube, second duct means, one end of which terminates
~ 10 within said chamber and the other end of which communicates
with the other portion of said third tube, and first
diaphragm means fixed inside the chamber between said
aperture and the terminations of said duct means and being
moveable to cover the terminations when the reference
lS pressure exceeds the pressure in the duct means to thereby
.3
prevent the flow of fluid from either duct means to the
... , . I
other, and being moveable away from the terminations when~'::, .
the pressure in the duct means exceeds the reference
pressure to thereby allow the flow of fluid from either
duct means to the other.
.... ,: . ,
. '~,;
` :
~1 The invention will now be described with reference
.,.,.~,
' to the accompanying drawings showing by way of example,
:!
. pressure responsive valve constructions that in accordance
.. -~. .
'. ' .
.. ~
. ~. .
.
. .~. .
~'" ' .
-
. ` ;, .
105;~6~9
with the invention, and also the combination in the
canulla of such valve constructions.
In the accompanying drawings:
Fig.l is a cannula which includes a pressure
responsive valve made in a~cordance with the principles
of the present invention;
Figs. 2A and 2B are a side cross-sectional view and
a top sectional view respectively of one embodiment of the
valve of Fig. l;
Fig. 3 is a side cross-sectional view of another
i illustrative embodiment of the valve of Fig. l; and
Figs. 4A and 4B are a side cross-sectional view
and an end cross-sectional view respectively of still
another illustrative embodiment of the valve of Fig. l.
~ .
~i 15 Fig. l shows a single-needle cannula for use in
withdrawing blood from and returning blood to a patient.
~i' The cannula comprises a Y-shaped structure having a central
tube 2, one end of which 6 is tapered for insertion into
.
the body of a patient, a second tube 8 branching from
the other end of the central tube 2 for coupling the
cannula to a blood pump, and a third tube 4 also branching
from the other end of the central tube 2 for coupling the
. ~ . .
. ,
, .
.
:
105'~659
cannula to the dialyzer element. Each of the branching
tubes 8 and 4 communicate with the central tube 302.
A pressure responsive valve 10 is disposed in ~he
tube 4 for regulating and controlling the flow of fluid
through the tube. Specifically, when the atmospheric pressure
is greater than the fluid pressure in the tube 4, then the
valve 10 closes to prevent the flow of fluid through the
tube, and when the atmospheric pressure is less than the
fluid pressure in the tube, then the valve opens to allow
the flow of fluid. ,Although the valve 10 is controlled,
in part, by the atmospheric pressure, it will become
apparent from the discussion which follows that any re-
ference pressure appropriately applied to the valve could
be utillzed.
One illustrative embodiment of a pressure responsive
valve made in accordance with the present invention is
shown in Figs. 2A and 2B. The valve includes a housing
202 definLng a chamber 210 which communicates throu-gh
apertures 206 with the atmosphere or other reference
pressure source. The housing 202 also defines a passage-
way or duct 226, one end of which terminates within the
chamber 210, and the other of which terminates outside
the housing. A second passageway or duct 230 is also
defined by the housing and or.e end of this duct similarly
., ~ - .
.
105~659
terminates within the chamber 210 and the other end
terminates outside the housing. As indicated in Fig. 2A,
the termination 234 of the duct 226 and the termination
238 of the duct 230 define a substantially flat plane.
'
A diaphragm 218 is affixed within the chamber 210
and attached to the sidewalls thereof at the perimeter
220 (see Fig. 2B), to separate the upper portion of the
chamber 210 from the duct terminations 234 and 238. The
diaphragm 218 may be of uniform thickness and flexibility
- 10 or, as shown in Fig. ~, it may lnclude a substantiallyrigid, flat portion 222 of sufficient dimensions to cover
the terminatlon 234 and 238. When the atmospheric pressure
in the upper portion of the chamber ~10 exceeds the fluid
~, pressure in the ducts 226 and 230, the diaphragm 218 is
caused to move dGwnwardly so that the flat portion 222 of
the diaphragm contacts and covers the duct terminations
~t 234 and 238 to prevent fluid from flowing from either duct
to the other. (Fluid in the ducts is shown by arrows to
:, .
i be moving from le~t to right simply to illustrate fluid
flow when the valve is open. It should be understood that
~ the flow of the fluid may be in either direction). When the
-~' fluid pressure in the ducts exceeds the atmospheric pressure
~ in the upper portion of the chamber 2iO, the diaphragm 218
~, . .
.. . .
.
~ '
`, .
.,
105~59 - lo -
is caused to move upwardly unseating the flat portion 222
from over the duct terminatlons 234 and 238 so that fluid
may flow from either duct to the other.
'
As indicated earlier, the diaphragm 218 may be composed
S of any uniformly flexible material such as rubber or plastic
of sufficient flexibility to allow free movement thereof
onto and from off the duct termination or it may be composed
- partly of flexible material with a flat rigid portion 222.
: ,
The function of the flat rigid portion is to provide greater
strength to that portion of the diaphragm which is to cover
i the duct termination so that the possibility of the diaphragm
j bursting or tearing is minimized. This additional strength
;~ may only be needed where the pressure differential between
,, . .
,,`' the ducts and the atmosphere is fairly large.
:,, .
, .,
A second diaphragm 2~0 (shown in dotted line in Fig.
`'I .
2A) may be provided for protective purposas to prevent
~ntroduction into the ducts of excessive quantities of air
in case of a puncture of the diaphragm 218. The diaphragm
~', 240 is affixed to the exterior of the housing 202 at the
,.. ~,1, ' .
''?''~ 20 perlmeter 242 (Fig. 2B~ to ex~end over the relatively small
! apertures 20S. This diaphragm moves conjointly with the
.~, .~ .
~................. .
~:>....
.... .
... ,:. .
~'~.,,
:~`'' .
1~)5;~6S9 - 11-
diaphragm 218 so that when the diaphragm 218 moves to
cover the duct termination 234 and 238, the diaphragm 240
moves downwardly toward the apertures 206, and when the
diaphragm 218 moves upwardly away from the terminations
234 and 238, the diaphragm 240 also moves upwardly away
from the apertures 206. The diaphragm 240 seals the chamber
, 210 from the atmosphere so that if the diaphragm 218 were
to break or puncture , at most, only that quantity of air
or other fluid in the chamber 210 would be allowed into
the ducts 426 and 430 (with the diaphragm 240 preventing
flow of air through the apertures 206 into the chamber 210).
This could be important, for example, in the use of the
valve in the cannula of Fig. 1 to prevent introduction of
~ excessive quantitie.s of air into blood being carried by the; 15 cannula.
, .
., .
~i The diaphragm 240 could illustratively be composed
,:, .
, of rubber, plastic or other simiiar material.
.
: ;,
: .,
., ~ .
An alternative embodiment of the pressure responsive
~i~i valve is illustrated in Fig. 3. This valve operates to
occlude the passage of fluid therethrough when the fluid
pressure exceeds the atmospheric pressure and to allow
-' the flow of fluid when the atmospheric pressure exceeds
: ,, .
;,
: ' .
~, ~
i .
".1 . , ,
;., .
: ;,
,
, ~ ~
1~5~659 - 12 -
the fluid pressure (just opposite the opera.ion of the
valve shown in Figs. 2A and 2B). The embodiment of
Fig. 3 also includes a housing 3G2 which defines a chamber.
A diaphragm 318 is fixed in the chamber and attached to the
side walls thereof to divide the cha~b~r into a first
compar~unent 310 and a second ~omp~t~ent ~14. The diaphragm
318 is sealed against the side walls of the chamber so that
communication between the upper compartment 310 and the
- lower compartment 314 is prevented. The upper ccmpartmen~
. .
I 10 310 con~unicates with the atmospnere through a plurality
^~ of apertures 306. The 302 also de ines a passageway or
; duct 326, one end of which terminates within the lower
compartment 314 and the other end of which terminates
outside the housing. A second duct 33C is also provided,
one end of this duct terminating with n the lower compart-
ment 314 and the other end terminating outside the housing -~
,.i .
~' 302. The terminations 334 and 338 of the ducts 326 and
;, 330 respectively define a substantially flat plane as
generally indicated in Fig. 3. Note that the duct termina-
~ 20 tions are directed downwardly in the Fig. 3 embodiment
-~t whereas they are directed upwardly in the Fig. 2 embodiment.
~ The diaphragm 318 includes a substantially rigid por-
,~ tion 322 from which extends a stem 324. The stem 324
,;.~;~ , ' '
.~"~
. ^, .
.
:',;,
..
:''
,.. ~,
. .,
. ~ , ,
l~)S;~tiS9
- 13 -
extends generally in a direction perpendicular from the
plane o` the rigid portion 322 into the lower compart-
ment 314. A plate 342 is affixed onto the end of the
stem 324 so that the plane of the plate is ~enerally
parallei wi.th the plane o. th2 ri~id portion 322 of the
; diaphragm 313. The dimensions of the plate 342 are
sufficient to enable the plate to cover the duct termina-
tion 334 and 338 a~ general]y incicated in Fig. 3.
When the atmospheric pressure or otner reference
pressure in the upper compartment 310 exceeds the fluid
;:
pressure in the ducts 326 and 330, the diaphragm 318 is
caused to move downwardly thereby carrying the plate 342
, away from the duct terminations 334 and 338. Fluid is
:., thus allowed to flow from either duct to the other. (Again,
:~ 15 the fluid is illustrated by arrows as flowing in the valve
i~ from the let to the right, but the flow may be in either
direction). When the pressure of the ,luid in the com-
~` partment 314 exceeds the atmospheric pressure in the upper
compartment 310, the diaphragm 518 i.s caused to move
upwardly carrying the plate 342 upwardly to seat over and
cover the duct terminations 334 and 338 and thereby pre-
.... . .
;~ vent the flow of fluid from either duct to the other.
~ Thus, as described, the embodiment of Fig. 3 provides for
.;'. ' . " . .
. ~ .
.- . .
:
.
-
lnsz6ss
allowing the flow of fluid through the valve when the
atmospheric pressure exceeds the fluid pressure in the
ducts and for preventing the flow of fluid when the
atmospheric pressure is less than the fluid pressure in
the ducts.
If the valve Fig. 3 were us~d in a cannula of the -
type shown in Fig. 1, in which the branching tube 8 were
coupled to a blood pump, th~ valve would be disposed in ~-
the tube 3 and not in the branching tube 4 as shown. Then,
~` 10 when the pressure in the tube 8 were less than the atmospheric
.:
1~ pressure, the valve would allow blood to flow from the
,".,: . ...
patient to the blood pump, and when the tube pressure were
greater than the atmospheric pressure, the valve would
, occlude and prevent the flow of blood therethrough.
i.
~ 15 A second diaphragm 340 might also be included with
;~ the valve of Fig. 3 for the same purpose de~cri~ed for the
~ ,j .
j~ Fig. 2 valve -- to prevent excessive quantities of air from
,
~, entering the ducts 326 and 330 if the diaphragm 318 were
. .~, .
' to rupture.
'"'
'~t 20 Figs. 4A and 4B shows still another embodiment of a
~ '.i - '
~.l pressure responsive~valve, Fig. 4A ~eing a cross-sectional
. ::'1 .
.'~ . - .
:'~ ' . '
., . "~ .
......
. .: ,. .
., ~ .
: ,:
; . .
5;~;S9
- 15 -
side view and Fig. 4B being a cross-sectional end view. This
valve includes a housing 402 defining an interior chamber.
The top of the housing 402 includes a plurality of apertures
- 406 and bottom of the housing also includes a pluralit~ of
apertures 410. The apertures enab]e the interior of the
housing to communicate with the atmosphere (or other
reference pressure). Openings 414 and 418 are located in
either end of the housing 402 to enable the introduction
of fluid to and exit of fluid from the housing. A first
diaphragm 422 is affixed in the chamber of the housing
.,
o between the apertures 406 and the openings 414 and 418 as
shown in Fig. 4A. A second diaphragm 426 is also aff~xed
in the chamber between the apertures 410 and the openings
414 and 418 The diaphragms are affixed to the interior
walls of the housing to prevent communication between either
opening 414 or 418 and the apertures 406 and 410, and to
define a passageway through the housing 402 between the
`j openings. As best seen in Fig. aB~ the diaphragms are
joined at the interior side walls of the housing 402 at
locations 430 and 434.
'".' '
When the pressure at the ap~rtures 406 and 410 exceed
~, the pressure at the openings 414 and 418, the diaphragms~; 422 and 426 are caused to move together in close contact .
. .
. ~ .
:~
'.;
... .
., ~
~O5;~f~59
- 16 -
and prevent the passage of fluid between the openings
414 and 418. When the pressure at the openings 414 and
418 exceeds the pressure at the apertures 406 and 410,
the diaphragms are caused to move apart or separate and
allow the passage of fluid between the openings 414 and 418.
In this manner, the valve of Figs. 4A and 4B controls the
flow of fluid th~rethrough in accordanc.e with the pressure
at the openings 41.4 and 418 relative to a reference
pressure at the apertures 406 and 410.
. , -- .
::,
. ,, ' ,
,~
. y
.... ~ .
:s
, . . .
. .
~`
,~ . .
.
,
.~,
, ,;
. ''
., .
:.. ~. .
. .-'.: .
.
"' `
,-. "'
