U.S. patent application number 11/416930 was filed with the patent office on 2006-10-05 for medical valve with positive flow characteristics.
Invention is credited to Thomas F. JR. Fangrow.
Application Number | 20060224127 11/416930 |
Document ID | / |
Family ID | 24459496 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060224127 |
Kind Code |
A1 |
Fangrow; Thomas F. JR. |
October 5, 2006 |
Medical valve with positive flow characteristics
Abstract
A valve for selectively permitting a fluid flow between first
and second medical implements is disclosed. The valve has a housing
with an interface suitable for receiving a connector portion of a
first medical device such as a catheter, and a seal made of a
flexible material. The seal has a first end in fluid communication
with the interface, a second end suitable for receiving the second
medical device, and at least one slit in fluid communication with
the first end and the second end. The slit defines a restricted
fluid flow path and a relatively small interior volume when in an
undisturbed state, defines an expanded fluid flow path and a larger
interior volume upon the introduction of the second medical
instrument into the slit, and retracts to define a restricted flow
path and a small interior volume upon the withdrawal of the second
medical device from the seal.
Inventors: |
Fangrow; Thomas F. JR.;
(Mission Viejo, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
24459496 |
Appl. No.: |
11/416930 |
Filed: |
May 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11157216 |
Jun 20, 2005 |
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11416930 |
May 2, 2006 |
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10636163 |
Aug 7, 2003 |
6916309 |
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11157216 |
Jun 20, 2005 |
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09614001 |
Jul 11, 2000 |
6695817 |
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10636163 |
Aug 7, 2003 |
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Current U.S.
Class: |
604/247 |
Current CPC
Class: |
A61M 39/10 20130101;
A61M 2039/062 20130101; A61M 2039/263 20130101; A61M 2039/0205
20130101; A61M 39/26 20130101; A61M 2039/027 20130101; A61M
2039/0258 20130101; A61M 39/045 20130101; A61M 39/06 20130101; A61M
39/02 20130101; A61M 39/0247 20130101 |
Class at
Publication: |
604/247 |
International
Class: |
A61M 5/00 20060101
A61M005/00 |
Claims
1. A medical valve for selectively permitting fluid to flow between
a first medical device and a second medical device, the valve
comprising: a housing having an interface suitable for receiving a
connector portion of the first medical device; and a seal element
made of a flexible material, the seal element having a downstream
end in fluid communication with the interface, an upstream end
suitable for receiving the second medical device, and a normally
substantially closed passage in fluid communication with the
downstream end and the upstream end, the seal element comprising: a
body made of flexible material and having a downstream end and an
upstream end opposite the downstream end; and a transverse flange
near an upstream end of the body, the transverse flange having at
least one opening in fluid communication with the passage; and
wherein the seal body has a generally rectangular shape, and the
passage is generally substantially planar in an undisturbed state.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/157,216, filed Jun. 20, 2005, pending,
which is a continuation of U.S. patent application Ser. No.
10/636,163, filed Aug. 7, 2003, now U.S. Pat. No. 6,916,309, which
is a continuation of U.S. patent application Ser. No. 09/614,001,
filed Jul. 11, 2000, now U.S. Pat. No. 6,695,817, all of which are
incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to a medical valve, and in
particular to a valve which, when connected between a first medical
device, such as a fluid source, and a second medical device, such
as a catheter, facilitates fluid flow therebetween, and when the
first medical device is disconnected therefrom, induces a positive
flow of fluid through the valve in the direction of the second
medical device.
[0004] 2. Description of the Related Art
[0005] The manipulation of fluids for parenteral administration in
hospitals and medical settings routinely involves the use of
connectors and valves for selectively facilitating the movement of
fluids between two points. These valves are typically placed along
a fluid flow line leading to a patient or other destination. For
example, the tube may lead to a catheter having its tip positioned
within a patient.
[0006] The valve is arranged so that a fluid source or other line
may be connected thereto for providing a fluid flow from the source
to the patient. When the fluid source or line is removed, the valve
closes, sealing the line leading to the patient.
[0007] The element which is connected to the valve may comprise a
tube or other medical device such as a conduit, syringe, IV set
(both peripheral and central lines), piggyback line, or similar
component which is adapted for connection to the medical valve.
Unfortunately, prior art valves suffer from a problem arising from
the disconnection of these medical devices from the valve.
[0008] These valves define a space within them through which a
fluid or other material may flow from the device to the line on
which the valve is mounted. When the medical device is connected to
the valve, it typically occupies a portion of this internal valve
space, displacing the fluid (whether it be a liquid or air) within
the valve.
[0009] A problem arises when the medical device is disconnected
from the valve. When the device is disconnected, it no longer
occupies a portion of the space in the valve. The increase in space
within the valve causes the fluid in the valve and line to which
the valve is connected, to move to fill the space. In effect, the
removal of the device creates a suction force which draws fluid
into the valve.
[0010] In the medical setting, this movement of fluid is very
undesirable. When the valve is connected to a fluid line leading to
a patient, the movement of fluid through the line towards the space
in the valve has the effect of drawing blood from the patient in
the direction of the valve. A serious problem may result in that
this blood may clot and clog the catheter near its tip, rendering
it inoperable, and may even result in a clot of blood in the
patient, which may prove fatal.
[0011] One attempt at overcoming this clogging problem has been to
coat the inner surface of the catheter near its tip in order to
prevent blood from sticking to its interior surfaces. This method
has generally been unsuccessful in preventing clogging of the
catheter.
[0012] The risk of blood clogging of the catheter is significantly
heightened where the inner diameter of the catheter is small (e.g.,
27 gauge). These small catheters have the advantage, however, in
that they reduce the trauma and discomfort caused by insertion into
a patient. Because these catheters have a very small passage
therethrough, even a small suction force may draw sufficient amount
of fluid back through a catheter toward the valve to introduce
blood into the catheter tip, which blood may clog the catheter's
passage.
[0013] Overcoming the above-stated problem is made more difficult
when considering other criteria which the valve must satisfy. For
example, the valve should be arranged to so that it does not have
any fluid stagnation points. If the fluid is allowed to stagnate in
one or more areas of the valve, bacteria growth and other problems
may occur.
[0014] In addition, the valve should have an internal flow path
which is smooth. Sharp edges and corners may damage blood cells and
cause hemolysis.
[0015] A valve that overcomes the above-stated problems is
desired.
SUMMARY OF THE INVENTION
[0016] In accordance with one preferred embodiment, a medical valve
for selectively permitting fluid to flow between a first medical
device and a second medical device comprises a housing that has an
interface suitable for receiving a connector portion of the first
medical device, and a seal. The seal is made of a flexible material
and has a downstream end in fluid communication with the interface,
an upstream end suitable for receiving the second medical device,
and a normally substantially closed passage in fluid communication
with the downstream end and the upstream end. The passage has a
relatively small interior volume when in an undisturbed state and a
larger interior volume upon the introduction of the second medical
instrument into the upstream end of the passage. The passage
retracts to define a restricted flow path and a relatively small
interior volume upon the withdrawal of the second medical device
from the seal (the upstream end initially being sealed as the
second medical device is withdrawn) so that a fluid occupying the
interior volume is forced toward the downstream end as the passage
walls collapse.
[0017] In accordance with another preferred embodiment there is
provided a valve seal for use in a medical valve having an
interface for fluid communication with a first medical device. The
seal comprises a first end in fluid communication with the
interface, a second end suitable for receiving a second medical
device, and at least one slit in fluid communication with the first
end and the second end. The slit defines a restricted fluid flow
path and a relatively small interior volume when in an undisturbed
state, and defines an expanded fluid flow path and a larger
interior volume upon the introduction of the second medical device
into the slit. The slit retracts to define a restricted flow path
and a relatively small interior volume upon the withdrawal of the
second medical device from the seal.
[0018] In accordance with another preferred embodiment a method is
provided for causing a positive flow in the direction of a first
medical device from a valve that connects the first medical device
to a second medical device and has an associated seal. The seal is
adapted to receive at least a portion of the second medical device
and provide fluid communication between the first and second
medical devices. The method comprises the steps of withdrawing the
second medical device from the seal and
[0019] permitting the seal to retract from a large interior volume
to a relatively small interior volume so as to displace any fluid
within the seal in the direction of the first medical device.
[0020] In accordance with another preferred embodiment there is
provided a method of preventing blood from flowing out of a patient
into a catheter when a syringe is withdrawn from a valve between
the syringe and the catheter. The method comprises the steps of
connecting the downstream end of the valve to the catheter and
inserting the end of the syringe into a slit forming the upstream
end of a normally substantially closed seal passage that is located
in a resilient seal and is in fluid communication with the
downstream end of the valve. This causes the seal passage to open
while providing sealing contact between the syringe and the
upstream end of the seal passage. The method further comprises the
steps of injecting fluid from the syringe through the seal passage
to the catheter and into the patient, and withdrawing the syringe,
allowing the walls of the seal passage to return to their
substantially closed position while initially maintaining sealing
contact between the upstream end and the syringe. This provides a
force urging fluid in the passage toward the catheter.
[0021] In accordance with another preferred embodiment there is
provided a medical valve for selectively permitting fluid to flow
between a first medical device and a second medical device through
an associated seal. The valve comprises an interface suitable for
receiving a connector portion of the first medical device, and a
seal holder in fluid communication with the interface.
[0022] In accordance with another preferred embodiment a system for
administering fluid to a blood vessel of a patient comprises a
catheter having an upstream end and a downstream end that is
suitable for placement in fluid communication with the blood
vessel, and a syringe suitable for expelling fluid into the
catheter. The system further comprises a valve having a fitting
suitable for connection to the upstream end of the catheter and
providing selective fluid communication between the syringe and the
catheter. The valve further comprises a seal made of a flexible
material. The seal has a downstream end in fluid communication with
the fitting, an upstream end suitable for receiving the syringe,
and a normally substantially closed passage in fluid communication
with the downstream end and the upstream end. The passage has a
relatively small interior volume when in an undisturbed state and a
larger interior volume upon the introduction of the syringe into
the upstream end of the passage. The passage retracts to define a
restricted flow path and a relatively small interior volume upon
the withdrawal of the second medical device from the seal (the
upstream end initially being sealed as the syringe is withdrawn),
so that a fluid occupying the interior volume is forced toward the
downstream end as the passage walls collapse.
[0023] In accordance with another preferred embodiment there is
provided a method of making a medical valve seal of the type having
a body made of a flexible material and at least one slit formed
within the body between adjacent first and second slit walls. The
method comprises molding first and second preforms, each preform
comprising one of the first and second slit walls and a perimeter
edge portion, and pressing the first and second preforms together
so that the first and second slit walls face each other. The method
further comprises molding an additional amount of a flexible
material to at least part of the perimeter edge portions of the
first and second preforms so that the first and second preforms and
the additional material form a unitary mass with the slit formed
therein.
[0024] For purposes of summarizing the invention and the advantages
achieved over the prior art, certain objects and advantages of the
invention have been described herein above. Of course, it is to be
understood that not necessarily all such objects or advantages may
be achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objects or advantages as may be taught or suggested herein.
[0025] All of these embodiments are intended to be within the scope
of the invention herein disclosed. These and other embodiments of
the present invention will become readily apparent to those skilled
in the art from the following detailed description of the preferred
embodiments having reference to the attached figures, the invention
not being limited to any particular preferred embodiment(s)
disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Having thus summarized the general nature of the invention
and its essential features and advantages, certain preferred
embodiments and modifications thereof will become apparent to those
skilled in the art from the detailed description herein having
reference to the figures that follow, of which:
[0027] FIG. 1 is a schematic view of the use of a valve in
accordance with the invention to interconnect a catheter with a
fluid source such a syringe;
[0028] FIG. 2 is a perspective view of the valve;
[0029] FIG. 3 is a front elevation view of the valve;
[0030] FIG. 4 is a side elevation view of the valve;
[0031] FIG. 5 is a perspective view of a seal for use in the
valve;
[0032] FIG. 6A is a front elevation view of the seal;
[0033] FIG. 6B is a front cross-sectional view of the seal;
[0034] FIG. 7A is a side elevation view of the seal;
[0035] FIG. 7B is a side cross-sectional view of the seal;
[0036] FIG. 8A is a front elevation view of the seal;
[0037] FIGS. 8B-8D are cross-sectional schematic views of the
insertion of a medical device into the seal taken through lines
8B-8B, 8C-8C and 8D-8D of FIG. 8A, respectively;
[0038] FIG. 9 is a front cross-sectional view of a housing for use
in the valve;
[0039] FIG. 10 is a side cross-sectional view of the valve and the
syringe before insertion of the syringe into the valve;
[0040] FIG. 11 is a side cross-sectional view of the valve with the
syringe fully inserted;
[0041] FIG. 12 is a front cross-sectional view of the valve with
the syringe fully inserted;
[0042] FIG. 13 is a side cross-sectional view of the valve with the
syringe partly withdrawn;
[0043] FIG. 14 a side cross-sectional view of the valve with the
syringe further withdrawn in comparison to FIG. 13;
[0044] FIG. 15 is a side elevation view of an alternative
embodiment of the valve, with the syringe partly inserted;
[0045] FIG. 16 is a side elevation view of an alternative
embodiment of the valve, with the syringe fully inserted;
[0046] FIG. 17 is a front elevation view of the valve as used with
a syringe having a Luer lock;
[0047] FIG. 18 is a side elevation view of an alternative
embodiment of the valve housing;
[0048] FIGS. 19A-19E are schematic views of a process of making the
seal; and
[0049] FIG. 20 is a plan view of an overmold plate used in making
the seal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0050] FIGS. 1-9 depict a valve 20 in accordance with a preferred
embodiment of the invention. FIG. 1 illustrates a particular use of
the valve 20 to which it is well suited. Of course, the valve 20
may be used in a variety of other manners.
[0051] As illustrated in FIG. 1, the valve 20 may advantageously be
used to selectively control the flow of fluid to a first medical
device (such as a catheter 22 shown here) from a second medical
device (generally comprising a fluid source such as an ISO standard
syringe 24). In this arrangement, the catheter 22 is connected to
one end of the valve 20 and has a tip 26 inserted into the arm of a
patient. The syringe 24 has a cannula tip or Luer 28 that is
inserted into the other end of the valve 20, which is designed to
accept the Luer 28 of the syringe 24 without a needle installed on
the Luer.
[0052] When so connected, the valve 20 permits fluid to flow from
the syringe 24 to the catheter 22 and into the patient. The valve
20 is also arranged so that when the syringe 24 is disconnected,
fluid flow through the valve 20 is prevented. In addition, when the
syringe 24 is disconnected, the valve 20 generates a "positive"
fluid flow, i.e. flow of fluid in the direction of the patient,
thereby preventing blood from entering the catheter 22 and causing
the associated adverse effects.
[0053] FIGS. 2-4 depict one preferred embodiment of a valve 20 in
accordance with the invention. The valve 20 comprises a relatively
rigid housing 30 and a relatively flexible and resilient seal 32
disposed on or within the housing 30. The housing 30 has a Luer
lock interface 34 at its lower end to facilitate connecting the
valve 20 to a variety of medical devices. One skilled in the art
will readily appreciate that a number of other interface or
connection types are suitable for use in place of the Luer lock 34,
such as a Luer slip connection or a barbed hose fitting.
[0054] The seal 32 has a slit opening 36 (best seen in FIG. 2)
which is configured to permit the Luer 28 of a syringe 24 (see FIG.
1) to enter the seal 32 upon application of moderate pressure by
the user. The syringe Luer 28 thus enters a slit 38 (see FIG. 3)
formed in the interior of the seal 32. With the syringe Luer 28
thus inserted, the seal permits fluid ejected from the syringe 24
through the Luer 28 to flow through the slit 38 and Luer lock 34
and into the catheter 22 or other medical device attached to the
Luer lock 34.
[0055] FIGS. 5-7B show the seal 32 removed from the housing for
purposes of clarity. The seal 32 has a body 40 which may take the
form of a slab having a flat, generally rectangular shape. Like the
entirety of the seal 32, the body 40 is preferably formed of
molded, 50 durometer silicone rubber, or is alternatively formed of
synthetic polyisoprene. At one end of the body 40 is formed a flat,
generally rectangular neck 42 and a generally circular transverse
flange 44. The neck 42 is situated between first and second lateral
extensions 43a, 43b which have shoulders 43c, 43d comprising those
portions of the lateral extensions nearest the flange 44. The body
40, neck 42 and flange 44 thus form an integral unit, inside of
which is formed the (preferably substantially planar) slit 38. The
slit 38 extends from the slit opening 36 (best seen in FIG. 2) in
the flange 44 to a lead lumen 46 formed in an end of the body 40
opposite the flange 44. The lead lumen 46 is preferably
substantially cylindrical and centered about an axis that is
substantially parallel to or collinear with the longitudinal axis
of the seal. The slit 38 is preferably substantially planar and of
virtually no thickness unless a Luer is connected. The slit 38 thus
forms (in its undisturbed state, i.e. when the syringe Luer 28 has
not been inserted into the seal 32) a highly restricted fluid flow
path from the slit opening 36 to the lead lumen 46. As used herein
in reference to a flow path, "restricted" means a flow path that
permits either no fluid, or a clinically negligible amount of
fluid, to pass.
[0056] The preferred configuration of the slit 38 and lead lumen 46
is best seen in FIGS. 6A-7B. The slit 38 has a body portion 48
within the body 40 of the seal 32. Advantageously, the body portion
48 is a region of maximum width, preferably about 0.228'', of the
slit 38. The slit 38 tapers to a point or region 50 of minimum
width, which is preferably located within the neck 42.
Advantageously, at the region 50 of minimum width the slit 38 is
preferably about 0.120'' wide. In other words, the width of the
slit 38 in the body portion 48 is almost twice that of the region
50 of minimum width. From the region 50 of minimum width the slit
38 tapers outward to the slit opening 36, where it attains a
preferred width of about 0.200''. This tapered configuration acts
as lead-in for insertion of the syringe Luer 28 into the slit 38.
The slit 38 may also have beveled corners 52 at its lower end,
opposite the neck 42. At its lower end the slit 38 connects to the
lead lumen 46 to facilitate fluid communication between the slit 38
and the lead lumen 46. The lead lumen 46 preferably has a lead-in
chamfer 54 and a beveled transition 56 to the slit 38. The
preferred inside diameter of the lead lumen 46 is about
0.040''.
[0057] In the side views of FIGS. 7A and 7B, it may be seen that
the seal 32 has a T-shaped cross section before installation in the
housing 30, with the flange 44 forming the cross portion of the
"T". Viewed from the side, the slit 38 is uniformly thin, i.e. of
no or virtually no thickness, as it runs from the top of the seal
32 to the lead lumen 46. However, upon installation in the housing
30, the thickness of the slit 38 (when viewed from the side) will
vary somewhat as will be explained in greater detail below.
[0058] FIGS. 8A-8D show the effects, in terms of sealing
performance, of the varying width of the slit 38 after introduction
of a syringe Luer 28 into the slit 38. (The syringe Luer 28 is not
shown in FIG. 8A for purposes of clarity.) FIG. 8B shows the
arrangement of the slit 38 and the syringe Luer 28 at the region 50
of minimum width, when the Luer 28 has been fully inserted into the
slit 38. Due to the relative narrowness of the slit 38 at the
region 50, the slit 38 draws up against substantially the entire
perimeter of the syringe Luer 28 at that location, creating a
relatively tight perimeter seal between the slit 38 and the Luer
28. In other words, the perimeter of the open slit 38 at the region
50 is less than the circumference of the Luer 28.
[0059] FIGS. 8C and 8D show that where the slit 38 is wider (i.e.,
in the body portion 48 of the slit and the transition from the
region 50) the slit no longer contacts the entire perimeter of the
syringe Luer 28, leaving gaps 57 on one or both sides and the end
of the Luer 28. In other words, the perimeter of the open slit in
the body portion 48 is greater than the circumference of the Luer
28. As will be discussed in greater detail below, this arrangement
of a slit-Luer seal near the top of the slit 38 and a
fluid-occupiable volume (in the form of the gaps 57) below the
slit-Luer seal, promotes a positive-flow function for the valve 20
when the syringe Luer 28 is withdrawn.
[0060] FIGS. 3, 4, and 9 show a preferred configuration of the
housing 30 and the installation of the seal 32 therein. The housing
30 is preferably formed of molded polycarbonate, or alternatively
formed from any suitable thermoplastic. The housing 30 has a seal
holder 58 attached to the Luer lock 34; the seal holder preferably
has a cylindrical configuration, but may comprise any shape or
construction sufficient to hold the seal 32 on or in the housing 30
without interfering with operation of the valve 20. The seal holder
has an axial opening 60 opposite the Luer lock 34, and first and
second side openings 62a, 62b which have first and second top edges
63a, 63b that comprise the edges of the side openings nearest the
axial opening 60. A lead cannula 64 (best seen in FIG. 9) extends
from the Luer lock 34 toward the axial opening 60 and contains an
internal lumen 66 which is in fluid communication with a lumen 68
in the Luer lock 34. The lead cannula 64 is preferably
substantially cylindrical or frusto-conical in shape and centered
about an axis that is substantially parallel to or collinear with
the longitudinal axis of the housing 30. A pair of lugs 70 are
positioned on the end of the seal holder 58 near the axial opening
60, to permit a Luer lock or other threaded connection (not shown)
to threadably engage the housing 30 at the axial opening 60.
[0061] As best seen in FIGS. 3 and 4, most of the seal 32 is
situated within the seal holder 58, with the first and second
lateral extensions 43a, 43b of the seal 32 protruding from the
first and second side openings 62a, 62b. The lead lumen 46 of the
seal 32 is situated so that the lead cannula 64 extends at least
partway into the lead lumen, facilitating fluid communication
between the seal 32 and the Luer lock 34. The flange 44 covers the
axial opening 60 and contacts the adjacent edges of the opening.
Preferably, the distance between the axial opening 60 and the top
edges 63a, 63b of the side openings 62a, 62b is slightly larger
than the distance between the flange 44 and the shoulders 43c, 43d
of the lateral extensions 43a, 43b. This arrangement results in the
application of a tensile force or preload to the seal 32 between
the flange 44 and the lateral extensions 43a, 43b. The preload
arises as the shoulders 43c, 43d bear against the top edges 63a,
63b and the flange 44 bears against the edges of the axial opening
60. The preload causes the flange 44 to assume a slightly
bowl-shaped or concave configuration as the edges of the axial
opening 60 bear against the underside of the flange 44. The
bowl-shaped flange 44 thus serves as a lead-in for the insertion of
the syringe Luer 28 into the slit opening 36 (best seen in FIG. 2),
and tends to pinch closed the slit opening 36 and thus enhances the
ability of the seal 32 to prevent fluid flow. The preload also
prevents buckling of the seal along its longitudinal axis and
maintains the sides of the slit 38 in close proximity along their
entire length. The preload thus promotes a relatively thin slit
below the flange 44, which enhances the sealing performance of the
slit 38.
[0062] FIGS. 10-14 illustrate the function of the valve 20 as a
syringe Luer 28 is inserted into and withdrawn from the slit 38.
FIG. 10 shows the valve 20 prior to insertion of the syringe Luer
28; at this point the slit 38 defines a substantially closed or
highly restricted flow path through the seal 32, marked by a very
thin (or substantially nonexistent) path thickness T.sub.min
between slit walls 72a, 72b. This thin or nonexistent path
thickness T.sub.min prevails along most or substantially all of the
length of the slit 38 below the flange 44. This condition restricts
fluid flow through the seal 32 so as to seal off the catheter 22
(see FIG. 1) or other medical device connected to the Luer lock 34.
At this point the slit 38 also defines a relatively small interior
volume V.sub.min within the seal 32, between the slit walls 72a,
72b. (As used herein in reference to an interior volume of the
seal, "relatively small" means a volume that is either nonexistent
or clinically negligible in size.) In this initial state, the seal
32 is situated upon the lead cannula 64 such that substantially
none of the lead cannula 64 extends into the slit 38.
[0063] FIGS. 11 and 12 show the valve 20 after the syringe Luer 28
has been completely inserted into the slit 38. The seal 32 has also
been stretched or forced downward onto the lead cannula 64, at
least part of which penetrates into the slit 38 itself. At this
point the slit 38 defines an expanded flow path through the seal
32, in that the slit walls 72a, 72b have spread to a path width
T.sub.max. The seal 32 thus permits fluid to flow between the
syringe 24 and the catheter 22. In addition, the slit 38 now
defines a larger or maximum interior volume V.sub.max. V.sub.max
comprises the entire space between the slit walls 72a, 72b less the
volume taken up by the cannula (but not the internal lumen) of the
syringe Luer 28 and less that portion of the lead cannula 64 which
has penetrated into the slit 38. Accordingly, under pressure
exerted via the syringe 24 an amount of fluid substantially
equivalent to V.sub.max now fills the slit 38 between the slit
walls 72a, 72b. This is also shown as gaps 57 in FIGS. 8C and
8D.
[0064] FIGS. 13 and 14 show the function of the slit 38 as the
syringe Luer 28 is withdrawn from the valve 20. As the syringe Luer
28 and lead cannula 64 exit the slit, the slit walls 72a, 72b
retract to substantially their original configuration to once again
define a narrow path width (approaching T.sub.min) between them.
This retraction of the slit walls 72a, 72b reduces the volume
between the walls; that is, the internal volume within the slit 38
is decreasing from V.sub.max. Thus the amount of fluid within the
slit must also decrease from V.sub.max. Accordingly, the retracting
slit walls 72a, 72b displace the fluid from the slit 38 as the
syringe Luer 28 is withdrawn.
[0065] The fluid thus displaced cannot flow out of the slit 38
through the top of the seal 32. As detailed above with regard to
FIGS. 8A-8B, the slit 38 maintains a tight seal against the syringe
Luer 28 at the region 50 of minimum width as the syringe Luer 28 is
withdrawn. In addition, the displaced fluid cannot flow into the
interior of the syringe 24 at all times relevant to the use of the
valve 20. Therefore, substantially all of the displaced fluid must
exit the slit 38 through the lead cannula 64 and Luer lock 34,
resulting in positive flow from the valve 20 upon withdrawal of the
syringe Luer 28.
[0066] FIGS. 15-18 show variations on the valve 20 disclosed above,
which variations may be desirable under certain operating
conditions. For example, as seen in FIGS. 15 and 16 the housing 30
may have a break 74 running vertically between the axial opening 60
and one or both of the side openings 62a, 62b. The break 74 permits
the seal holder 58 to spread open as a Luer slip 28 (as opposed to
a Luer lock 76 shown in FIG. 17) is inserted into the seal 32. This
spreading action has been found to be advantageous for using the
valve 20 with a Luer slip 28, as the valve 20 becomes less likely
to squeeze or pinch the Luer 28 out of the seal 32.
[0067] FIG. 18 shows an alternative configuration of the housing
30, with a curved or streamlined appearance in comparison to the
housing disclosed above. Both this type of housing or the type
disclosed above, may have an external coating or layer of a
relatively soft, pliant material such as a thermoplastic elastomer
to enhance operator comfort and to promote the theme of a valve 20
that provides a connection without the use of sharp, puncturing
elements such as needles or blades.
[0068] FIGS. 19A-21 depict a preferred method of making the seal
32. First, a pair of preforms 202a, 202b are molded between first
and second mold pairs 204a, 204b and 206a, 206b respectively. Each
preform 202 has a generally planar portion 208 that, in the
completed seal 32, forms a wall of the slit 38 (see FIGS. 6A-7B). A
flange portion 210 is also integrally molded into both preforms
202. The sides of the flange portion 210 are preferably set back
from the upper face of the planar portion 208, to provide a space
for overmold material (discussed in further detail below) to flow
between and connect the flange portions 210. The molding of the
preforms 202 is accomplished using conventional techniques and
equipment, preferably by injecting a thermoset material into the
cavity formed between the mold pairs 204a, 204b and 206a, 206b and
heating the molds and/or material to the set temperature of the
specific material used. Pressure may be applied as needed to
prevent material from leaking between the halves of the mold.
[0069] After this initial molding step, the mold halves 204a, 206a,
with the preforms 202a, 202b still positioned in them, are pressed
together with an overmold plate 212 positioned between the mold
halves, as depicted in FIGS. 19B-19C. The overmold plate 212, best
seen in FIG. 20 (with the outline of the preforms 202 also shown in
phantom), comprises a generally planar plate body 214 with an
overmold opening 216 cut into the body 214. The overmold opening
216 has a plan perimeter that conforms to the outer edges of the
completed seal 32, and may include a mandrel 218 that projects from
the lower portion of the opening 216 and forms the lead lumen 46
(see FIGS. 6A-7B) during the overmold process, as will be discussed
in greater detail below. The contacting faces of the mold halves
204a, 206a and the overmold plate 212 are advantageously
substantially planar. Thus the mold halves 204a, 206a, plate 212,
and preforms 202a, 202b define a mold cavity or volume 220 between
the walls of the overmold opening 216 and the outer edges of the
preforms 202a, 202b, and between the faces of the mold halves 204a,
206a.
[0070] With the mold apparatus (mold halves 204a, 206a and overmold
plate 212) arranged as shown in FIG. 19C, additional thermoset
material is injected into the mold apparatus to fill the mold
cavity 220 and form the remainder of the seal 32. Preferably, the
additional material is injected soon (i.e., a few seconds) after
the preforms 202 are molded and while they are still somewhat hot
from the initial molding. The additional material injected into the
mold cavity 220 bonds to the edges of the preforms 202 and forms
the edges of the slit 38 in the completed seal 32. In other words,
the remainder of the seal is overmolded onto the "sandwich" of
preforms 202. Preferably, the preforms 202 are pressed together
with sufficient force during the overmolding process to prevent the
additional material from migrating between the contacting surfaces
of the preforms 202. This preserves the patency of the slit 38 by
preventing the contacting faces of the preforms 202 from bonding to
each other during the overmold step.
[0071] The overmold plate 212 may be made with a thickness
approximately the same as that of the "sandwich" of preforms 202a,
202b to define a mold cavity 220 that, as described above,
comprises the open space between the walls of the overmold opening
216 and the outer edges of the preforms 202a, 202b, and between the
faces of the mold halves 204a, 206a. This overmold opening thus
also has a thickness approximately equal to that of the preform
sandwich, and all or nearly all of the overmold material injected
therein bonds only to the edges of the preforms 202a, 202b. In an
alternative embodiment, the overmold plate 212 may have a thickness
greater than the preform sandwich. This thicker, alternative
overmold plate thereby defines a mold cavity that also includes
open space that is created between the mold halves 204a, 206a and
the outer (i.e., facing away from the slit in the completed seal)
faces of the preforms 202a, 202b. The mold halves 204a, 206a are
preferably configured with projections, ridges, channels, gaps or
the like to create such space during this alternative overmold step
while pressing the preforms together as may be needed during the
overmold. Accordingly, in this embodiment the overmold material
bonds to both the edges and to the outer faces of the preforms
202a, 202b. In other words this alternative overmold step involves
injecting the overmold material into a mold cavity that surrounds
most or all of the preform sandwich, rather than overmolding to the
only the edges of the preforms.
[0072] It is preferred that the material added in the overmold step
is similar to that utilized in molding the preforms 202; however,
in other embodiments the preform material and the overmold material
may comprise different but nonetheless suitable materials for
manufacturing the seal, as discussed above. Therefore as used
herein "a flexible material" refers to any material selected from
the class of suitable seal materials as disclosed.
[0073] After the overmolding is complete, the mold halves 204a,
206a are removed from the seal plate 212, which now contains a
substantially completed seal 32, as seen in FIGS. 19D-19E. The
completed seal 32 is easily removed from the seal plate 212, and
the seal thus formed comprises, as discussed above, a unitary mass
of molded material with the slit arranged within it.
[0074] Although this invention has been disclosed in the context of
certain preferred embodiments and examples, it will be understood
by those skilled in the art that the present invention extends
beyond the specifically disclosed embodiments to other alternative
embodiments and/or uses of the invention and obvious modifications
and equivalents thereof. Thus, it is intended that the scope of the
present invention herein disclosed should not be limited by the
particular disclosed embodiments described above, but should be
determined only by a fair reading of the claims that follow.
* * * * *