Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DESCRIPTION
FLOW CONTROL APPARATUS
Background of the Invention
The field of the present invention is flow control
devices and particularly such devices as are employed with
intravenous catheters.
With the advent of sophisticated monitoring equip-
Monet it has become common practice in hospitals and
particularly in intensive care facilities to maintain a
continuous monitoring of certain body functions. This
monitoring often includes intravenous sensing requiring a
hollow catheter. The advantages of continuous monitoring
of blood pressure and the like using such a hollow
catheter have made this practice routine. However such
catheters are subject to blinding by blood clotting over
- the end in the vein or artery. A relatively successful
solution to such blinding has been devised which includes
a small medical fluid flow through the catheter. To
this end, capillary tubes have been employed. The
capillary flow is, however, only a partial solution to the
problem. Use of such a system requires a compromise
between excessive volumes of flow into the body and
insufficient flow to assure against blinding.
To prevent excessive flow into the body and yet
provide some means for overcoming clotting, an additional
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solution has been employed. A manually controlled high volume
flow sufficient to insure against blinding of the catheter is
used. The high volume flow is also useful for initially filling
the catheter line with fluid, for removing air bubbles and the
like. Such devices incorporating this Buffalo concept include
USE Patent No. 3,675,891 entitled "Continuous Catheter Flushing
Apparatus" to Reynolds, et at and US. Patent No. 4,192,303
entitled "Flow Restricting Device for Artificial Catheter
Systems" to Young et at. The Reynolds et at and Young et at
patents are indicative of the prior state of the art and to
provide further illustration of utility of the present invention.
In overcoming difficulties in durability and convenience
of use, a device has been developed which is disclosed in US.
Patent Noah filed October 16, 1981, to Sullivan,
entitled "Flow Control Apparatus". The disclosed device includes
a resilient block of material with at least one passage there-
through. This block is incorporated in a housing having a hollow
body and a plunger. The plunger is also hollow, is slid ably
positioned in the hollow body and extends therefrom such that
by compressing the hollow body and the plunger together, the
resilient block is compressed and the passage therein deformed.
The passage includes a ball therein which acts as a valve. The
deformation of the passage is designed to allow fast flow past
the valve.
The Sullivan device was designed to promote deformation
of the resilient block solely -through compression on the ends
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thereof. The resulting lateral deformation was generally
random as the movement of resilient material around the passage
could not be controlled by the operator through simple
compression of the device. As particular movement could not
be assured, the fit between the valve and the resilient
block could not be in substantial
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interference. However, to insure against valve leakage, some
interference fit between the valve and the passage was required.
Consequently, a very narrow range of fit between the valve and the
resilient block was required in the Sullivan device to gain
reasonable reliability. Demanding tolerances and complicated
or extensive reliability testing can create production and cost
difficulties.
Summary of the Invention
The flow control apparatus of the present invention is
a successor to the aforementioned Sullivan device, similarly
overcoming the difficulties in reliability and use of earlier
prior art. Furthermore, the present invention overcomes and
circumvents the disadvantages of valve performance and manufacture
resulting from the exacting requirements of the earlier Sullivan
device .
According to one aspect of the present invention there
is provided a flow control apparatus including a housing having
a hollow body and a plunger slid ably positioned in and extending
from said hollow body, said housing including a central cavity
defined by said hollow body and said plunger, an inlet into said
central cavity and an outlet from said central cavity; a block
of resilient material positioned in said central cavity between
said inlet and said outlet and having a first passage there through
oriented to provide communication between said inlet and said
outlet; and a valve member in said pesky, one of said hollow
body and said plunger including a first member affixed thereto
and extending into said first passage and the other of said hollow
body and said plunger including a second member affixed thereto
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and in said first passage on the other sue of said valve member
from said first member, wherein the improvement comprises said
first and second members being constructed and arranged to
extend to and displace said valve member against one side of
said first passage when said hollow body and said plunger are
compressed toward one another against said resilient material.
According to a second aspect of the invention there is
provided a flow control apparatus including a housing having a
hollow body and a plunger slid ably positioned in and extending
from said hollow body, said housing including a central cavity
defined by said hollow body and said plunger, an inlet into said
central cavity and an outlet from said central cavity; a block
of resilient material positioned in said central cavity between
said inlet and said outlet and having a first passage there-
through oriented to provide communication between said inlet
and said outlet, and a valve member in said passage, said hollow
body including a first member affixed thereto and extending into
said first passage and said plunger including a second member
fixed thereto and extending into said first passage on the other
side of said valve from said first member, wherein the improvement
comprises said first and second members being constructed and
arranged to extend to and displace said valve member against one
side of said first passage when said hollow body and said plunger
are compressed toward one another against said resilient material,
said first member including a distal end having a first end
surface which is other than perpendicular to the center line of
said first passage and said second member including a distal end
having a second end surface which is other than perpendicular to
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the center line of said first passage, said first and second end
surfaces being oriented such that they are mutually divergent.
According to a third aspect of the invention there is
provided a flow control apparatus comprising in combination a
housing having a hollow body and a plunger slid ably positioned
in and extending from said hollow body, said housing including
a central cavity defined by said hollow body and said plunger,
an inlet into said central cavity and an outlet from said central
cavity; a block of resilient material positioned in said central
cavity between said inlet and said outlet and having a first
passage there through oriented to provide communication between
said inlet and said outlet; and a valve member in said first
passage, said valve member being a ball having a diameter in
interference fit with the inside diameter of said first passage,
one of said hollow body and said plunger including a first member
fixed thereto and extending into said, first passage to said valve
member and the other of said hollow body and said plunger include
no a second member fixed thereto and in said first passage on the
other side of said valve member from said first member, said,
first and second members being constructed and arranged to extend
to and displace said valve member against one side of said first
passage when said hollow body and said, plunger are compressed
toward one another against said resilient material, said first
member including a distal end having an end surface which is
other than perpendicular to the center line of said first passage.
According to a fourth aspect of the invention there is
provided a flow control apparatus comprising in combination a
housing having a hollow body and a plunger slid ably positioned in
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and extending from said hollow body, said housing including a
central cavity defined by said hollow body and said plunger, an
inlet into said central cavity and an outlet from said central
cavity; a block of resilient material positioned in said central
cavity between said inlet and said outlet and having a first
passage there through oriented to provide communication between
said inlet and said outlet; and a valve member in said passage,
one ox said hollow body and said plunger including a first member
fixed thereto and extending into said first passage to said
1.0 valve and the other of said hollow body and said plunger including
a second member affixed thereto and in said first passage on the
other side of said valve member from said first member, said
first and second members being constructed and arranged to extend
to and displace said valve member against one side of said first
passage when said hollow body and said plunger are compressed
toward one another against said resilient material, said first
passage being adjacent a surface of said block of resilient
material defining a wall there between, said wall being relatively
thicker immediately upstream of said valve member than adjacent
to and downstream of said valve member.
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Figure 1 is a perspective view of an assembled device
of the present invention
Figure 2 is a cross-sectional elevation taken along
line 2-2 of Figure 1.
Figure 3 is a cross-sectional plan taken along line
3-3 of Figure 2.
Figure 4 is a perspective view of a resilient block
according to the present invention.
Figure 5 is a cross-sectional elevation as in figure
2 with the resilient block in a deformed condition.
Detailed Description of the Preferred Embodiment
urging in detail to the drawings, a preferred
embodiment is illustrated as including a housing of rigid
plastic material The housing, generally designated 10
includes a hollow body 12 and a plunger 14. The hollow
body 12 includes an upstanding generally ocular sidewall
as best seen in Figure 3. The hollow body 12 further
includes a through passageway 16, integrally formed
therewith having a first end 18 and a second end 20
capable of accommodating conventional catheter tubing and
fittings.
The plunger 14 also includes an ocular wall as can
best be seen in Figure 3. The wall of the plunger 14 is
designed to fit in telescoping fashion within the ocular
wall of the hollow body 12. Together, the interior of the
hollow body 12 and the plunger 14 define an ocular cavity
which can be Yarned in height by telescoping the plunger
into and out of the hollow body 12. Naturally, other
shapes may be defined by the housing 10 without departing
from the present invention. Furthermore, the telescoping
arrangement may be reversed in that the upper portion
becomes the housing and the lower portion the plunger in
telescoping arrangement.
To fix the two parts, the hollow body 12 end the
plunger I together to both provide relative motion and
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prevent complete separation of the components, two tapered
keepers 22 and 24 are integrally formed with the plunger
14. The keepers are tapered or easy snapping together of
the hollow body 12 and the plunger 14 and yet retain the
parts together by means of the upper flanges thereon. The
keepers are positioned in slots 26 and 28 through the
ocular wall of the hollow body 12. The slots 26 and 28
provide sufficient depth to accommodate squeezing of the
housing in operation as illustrated in Figure 5.
The under surface 30 of the hollow body 12 and the
upper surface of the plunger 32 are designed to give
conventional manual purchase and are also sized to provide
an easy grip for an average hand. The surfaces 30 and 32
may be roughened or provided with grooves such as thus-
treated in Figure 1 to aid the operator in gripping the
apparatus.
Located on the plunger 14 is an inlet 34 resigned to
accommodate conventional tubing or fittings employed with
such devices. The inlet 34 includes a passageway 36
directed to the cavity in part defined by the plunger 14~
Thus, medical fluids and the like can be admitted through
the inlet 34 into the interior, or central cavity, of the
housing 10. To further define the central cavity, the
hollow body 12 includes an inward step or flange 38 having
the same inside cross-sec~ional dimensions as the plunger
14. Thus, the cavity is defined both top and bottom with
a common cross-section or careful location of the resilient
block contained therein at these points. Yet, an annular
space is allowed at 40 accommodating deformation of the
resilient block. This space 40 also accommodates movement
ox the plunger as can be seen by comparing Figures 2
and 5. An additional space for resilient block deform-
lion is also provided in the plunger 14 at 41.
The resilient block of material 42 contained within
the central cavity of the housing 10 is shown indepen-
deftly in Figure 4, in a relaxed state in Figure 2, and in
a compressed state in Figure 5. This resilient material
as employed in the preferred embodiment is a clear sift-
cone rubber having a Shore hardness of A-25. A wide range
of harnesses may be employed with the block 42 which will
affect the amount of force required to actuate the
mechanism.
The block 42 is generally ocular in shape -to fit
closely within the interior of the plunger 14 and the
inner flange 38. It includes an upstanding ocular flange
44 forming a continuous wall with the main block of
material. This upstanding flange 44 defines a cavity 46
which serves as a manifold for directing medical fluid
passing into the central cavity through the passageway 36
To accommodate this upstanding flange 44, the plunger 14
includes a groove 48 in the under surface thereof. The
groove 48 is sized to closely fit the flange 44 for
compression control when the housing 10 is squeezed. The
groove 44 is not so deep as to allow the plunger I to
completely fill the cavity of the manifold 46 defined
within the flange 44.
The block of material 44 includes a first passage 50
conveniently extending through the block I from the
manifold 46 to the other end of the block. This first
passage 50 is incorporated in defining the valving
mechanism of the flow control apparatus. Located within
the first passage 50 is the valve member 52~ In the
preferred embodiment, the valve member 52 is a ball
having a diameter which is in interference fit with the
relaxed inside diameter of the first passage 50. The ball
may be of dimensionally stable plastic material. Under
normal operation, the valve ball 52 provides a seal in the
passage 50 such that no flow is experienced. This condo-
lion is illustrated in Figure 2.
Associated with the hollow member 14 in substantial
alignment with and extending into the first passage 50 is
a first member 54. This first member 54 is smaller in
cross-section than the passage 50 such that flow is
unimpeded thereby. A second member 56 is associated with
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the hollow body 12 in alignment with and extending into
the first passage 50. This second member 56 includes a
central passageway 58 for flow there through. Again, flow
is unimpeded through the passage 50 by this second member.
The members 54 and 56 extend into the passage 50 to
the valve member 52. With the device in the relaxed
state, the members 54 and 56 are not in interference with
the valve member 52. This condition is illustrated in
Figure 2. When the housing is compressed, the members I
and 56 do interfere with the location of the valve as can
best be seen in figure 5. To promote predictable movement
of the valve member 52, the distal ends of the members 54
and 56 include end surfaces 59 and 60 which are other than
perpendicular to the center line of the first passage 50.
In the preferred embodiment illustrated, surfaces 59 and
60 are mutually divergent and are each generally planner.
This configuration predictably interferes with the valve
member 52 to force it in a given direction laterally
relative to the passage 50 under the force of compression
of the housing 10. Thus, random distortion of the past
siege and random location of the ball are avoided.
To avoid logy in the first passage 50 by over-
pressure upstream of the valve member 52, the first
passage 50 is divided into two sections. The first
section 61 is located above the valve member 52. The
passage is narrow in this section to provide additional
material around the passage. The ball is positioned
immediately below this area. Consequently, a maximum
length of passage above the valve member 52, which is
necessarily subjected to the greater pressure, is further
supported by additional material resulting from the
smaller diameter passage. Immediately adjacent to and
below the valve member 52 in the passage 50 there is a
second section 62. Because of the interference of the
valve member 52 to the flow, lower pressure is experienced
downstream of the valve member 52 in this second section
62. Thus, flexibility is provided adjacent the valve
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member 52 such that the valve may be laterally displaced
with comparative ease. Yet, additional strength is
provided upstream of the valve to prevent overpricer
from causing leakage in the valve.
A second passage 63 is provided conveniently through
the resilient block 42 from the manifold 46 to the other
end thereof. The second passage 63 is located at the
opposite end of the manifold cavity 46 and has a capillary
64 located therein. The capillary 64 may be selected from
any conventional capillary depending upon the amount of
flow desired. Such capillaries are normally of glass and
are rigid such that they cannot be deformed in the present
application.
Located below the capillary is an upstanding tube 65
formed integrally with the hollow body 12. The tube 65
also forms part of the outlet, draining into the through
passageway 16, the outer dimension of the tube 65 is
substantially equal Jo the outer dimension of the cavil-
lazy 64 to conveniently fit snugly within the second
passage 63. The tube 65 also acts to prevent the cavil-
lazy from sliding into the through passageway 16.
Located intermediate the first and second passages
50 and 63 is a space 66. The space 66 is positioned
adjacent the first passage to allow exaggerated deform-
lion of the wall of the passage 50 when the resilient block 42 is compressed. This space 66 extends only
partially through the block 42 to avoid flow there-
through. An upstanding pin 63 also formed integrally with
the hollow body 12 acts to control the deformation of the
wall of the passage 50 into the space 66 as can best be
seen in Figure 5.
Rooking then to the operation of the preferred
embodiment, the through passageway 16 may be conveniently
placed via passageway end 18 in communication with monk-
toning equipment such as a transducer or a controlled source of fluid. The opposite end of the through passage-
way 16 is connected to the catheter or other distribution
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mechanism for the monitored liquid. The inlet 34 is
coupled with a source of fluid which is to slowly flow
into the catheter for inhibiting clotting at the end
thereof. Under normal operation medical fluid intro-
duped through inlet 34 passes in a low volume flow therewith capillary 64 and into the through passageway 16. When
flushing of the system, or additional clearing of the
catheter, is required, an operator may grip the housing 10
so as to squeeze the two parts the hollow body 12 and the
plunger 14, toward one another. As the housing is
squeezed, the plunger, acting primarily on the upstanding
flange 44 on the block 42, compresses the resilient
material of the block I and distorts the passage 50 as
illustrated in Figure 5. The members 54 and 56 are
brought into interference with the valve ball 52 and
positively force it laterally against the side of the
passage 50. Thus, a path is created through the passage
50 around the valve ball 52. Release of the housing 10
removes the compression force from the resilient block 42
allowing the device to return to its relaxed state. In
doing so, the passage 50 closes around the valve 52 and
seals the passage once again. The increased thickness of
the material above the valve ball 52 acts in this shut-off
mode to resist leakage due to overpricer in the upstream
system.
Provided as an example only are the following dime-
signal relationships. The first passage 50 has a nominal
diameter of .115 inches. The upper section is restricted
as discussed above such that the inner surface of the
passage 50 adjacent the end of the resilient block 42 is
formed with a radius of .045 inches from the nominal
center line which is then tapered outwardly at a 30 angle
to the major center line of the resilient block ~12 to
intersect the larger diameter on either side of the
reduced radius. The valve ball 52 has a nominal diameter
of .150 inches. The resilient block is clear silicone
rubber having a Shore hardness of A-25 and the ball is
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of acutely resin. The thickness of the wall of the block
of resilient material 42 between the first passage 50 and
the end of the block most adjacent that passage and below
the location of the valve ball 52 is .0675 inches. The
upper wall portion is increased by the reduced radius
discussed above.
Thus, an improved flow control device capable of
facile one handed operation/ easy fabrication and
excellent reliability is disclosed. While embodiments and
applications of this invention have been shown and
described, it would be apparent to those skilled in the
art that many more modifications are possible without
departing from the inventive concepts herein. The invent
lion, therefore, is not to be restricted except in spirit
of the appended claims.
