Unitary sphincter valve assembly

A sphincter valve for controlling the flow of fluid through a fluid delivery line has a body molded of a unitary piece of substantially flexible silicone material. The body is formed with an outer shell, and interior tube disposed within said outer shell, an end portion, and a pressure chamber defined between the outer shell and the interior tube. A separate end cap is secured to and closes the end of the body opposite the end portion thereof and a central passageway extends through the interior tube and through the ends of the valve. In use, the valve is spliced in a fluid delivery line and the pressure chamber is coupled to a source of selectively deliverable pressurized air. When pressurized air is forced into the pressure chamber, the inward force created by the pressure collapses the interior tube onto itself shutting off flow through the valve.

TECHNICAL FIELD 
This invention relates generally to valves and more specifically to 
pneumatically or hydraulically controllable sphincter valves. 
BACKGROUND OF THE INVENTION 
In a variety of medical applications, valves are used to control the inflow 
and outflow of fluids into and out of a patient's body. Such applications 
include, among others, blood transfusions, stomach evacuations, heart lung 
machine procedures, and colonic lavage for the removal of fecal impactions 
from a patient's bowels. In the case of colonic lavage, it is common that 
a first valve is connected in the liquid supply line of the lavage 
apparatus to control the inflow of water or other lavage liquid into a 
patient's colon for hydrating and loostening impacted fecal material. A 
second valve is connected in the drain line. This second valve usually is 
closed during fluid inflow to allow the bowels of the patient to fill with 
fluid. The second valve can then be opened to allow fluid and loosened 
fecal material to flow out of the patients colon to an appropriate 
receptacle. 
Valves used in colonic lavage systems and, indeed, in other medical 
applications, are subject to a number of relatively severe operational 
constraints. First, such valves must be extremely reliable because the 
lives of patients can and often are dependent upon their flawless 
operation. In addition, the valves must be gentle in that they must open 
and close in such a way that fluid flow is not stopped or started 
abruptly, which can shock a patient's system or damage delicate tissues. 
This is particularly true in the case of colonic lavage procedures because 
colon walls are thin and subject to rupture under abrupt stresses. It is 
also important in colonic lavage procedures that valves used in the system 
have the ability to cause a rapid pulsing of the lavage inflow liquid to 
aid in the loosening of fecal impactions. In addition, such valves must be 
opened reliably and automatically in response to excess back pressure from 
the colon in order to prevent damage to the colon as a result of excess 
fluid pressure. 
In the past, a variety of valves have been used in medical procedures such 
as those discussed above. In many cases, a sphincter valve design has been 
adopted because of its many advantages. In a sphincter valve, 
communication through the valve is closed by squeezing or collapsing a 
flexible tube within the valve through which the fluid passes. The valve 
is opened by releasing the flexible tube to allow the fluid to flow. This 
squeezing and releasing has been accomplished in a number of ways. In a 
heart lung machine, for example, the tube is squeezed and released by 
moving rollers that intermittently engage, compress, and roll along a 
short length of the tube. This action not only closes the valve, it also 
has the effect of pumping fluid intermittently through the tubing. In 
another type of sphincter valve, a mechanical plunger is actuated to 
engage and compress the flexible tube to close off communication 
therethrough. 
One sphincter valve design that has proved itself reliable is the 
pneumatically controlled sphincter valve. Such valves have proven 
particularly useful in colonic lavage systems. In these types of valves, a 
short, flexible, collapsible tube is enclosed within a pressure chamber 
coupled to a source of compressed air. The tube is coupled or spliced into 
the lavage liquid delivery line to control lavage fluid inflow. A similar 
valve may be spliced into the waste drain line to control the flow of 
contaminated fluid from the patient's colon. When it is desired to close 
one of the valves, pressurized air is injected into the pressure chamber. 
This generates inward force that collapses the interior tube and shuts off 
the flow therethrough. 
In the past, pneumatic sphincter valves have been constructed of a hard 
injection molded plastic outer shell having corresponding injection molded 
end caps that can be glued in place to form a generally cylindrical 
pressure chamber. A short tubular nipple communicates with the interior of 
the chamber and projects outwardly from the side thereof for selective 
delivery of pressurized air to the pressure chamber. Each of the end caps 
is molded with a short tubular coupler that extends and communicates 
through the end cap and that has an interior end within the chamber and an 
exterior end outside the chamber. A length of flexible surgical tubing is 
secured at its ends to the interior ends of the couplers communicating 
therebetween. The entire assembly is spliced into a liquid delivery or 
drain line by cutting the line if necessary and coupling the cut ends of 
the line to the exterior portions of the tubular couplers. Thus, fluid can 
flow from one section of the line, through the flexible tube within the 
chamber, and into the other section of the line. The tubular nipple is 
coupled to a source of selectively deliverable compressed air. When it is 
desired to shut the valve off, compressed air is injected into the 
pressure chamber, exerting pressure on the flexible tube within to 
compress and collapse the tube, thus shutting off the flow. For opening 
the valve, the pressure is simply released. 
While the just described pneumatic sphincter valve design has proved useful 
and reliable, it nevertheless embodies certain problems and shortcomings 
inherent in its design. For example, the valve is relatively expensive to 
manufacture because key components are injection molded. Further, the 
valve is time consuming and thus expensive to fabricate because the 
internal flexible tube must be installed manually and the end caps and 
other components must be glued to the chamber by hand. The hard plastic 
shell of the chamber can shatter if dropped and is uncomfortable to the 
skin of a patient such that the valve cannot comfortably be laid or rested 
on the patient during use. Finally, since the flexible internal tube of 
the valve is separate and made of a different material than other valve 
components, it can, under certain circumstances, come loose from the 
couplers within the valve causing the valve to fail and risking 
contamination of the compressed air supply. 
For these reasons, and particularly due to the expense of production and 
fabrication, conventional pneumatic sphincter valves have not been 
economical for use with disposable colonic lavage kits designed to be 
discarded after a single use. Accordingly, such disposable kits have been 
expensive and thus not easily available to lower income persons or 
patients on fixed incomes. There is thus a need for a reliable, 
unbreakable, and economical sphincter valve that can be used with colonic 
lavage and other medical procedures and discarded after use. It is to the 
provision of such a sphincter valve that the present invention is 
primarily directed. 
SUMMARY OF THE INVENTION 
Briefly described, the present invention, in one preferred embodiment 
thereof, comprises a unitary sphincter valve assembly intended primarily 
for use in medical applications such as colonic lavage procedures. The 
assembly preferably is molded in a single molding step from a translucent, 
opaque, or pigmented pliant silicone material. The completed assembly is 
formed from two parts, a main body and an end cap, each of which is molded 
of a unitary piece. The main body of the assembly is formed to define a 
generally cylindrical relatively thick walled outer shell and a relatively 
thin walled interior tube that extends coaxially within the outer shell 
and that has a central passageway. A pressure chamber is defined between 
the outer shell and the interior tube and the central passageway continues 
and communicates through the end of the main body where a female coupling 
nipple provides a means for coupling the valve in a fluid delivery line. 
The outer shell of the main body is formed with a tubular coupling nipple 
that projects outwardly from the wall of the outer shell and communicates 
with the pressure chamber between the outer shell and the interior tube. 
Molded simultaneously with and of the same silicone material as the main 
body is an end cap that, in use, is inserted in the other end of the main 
body to form the completed valve assembly. The end cap has a central 
passageway, an inwardly projecting plug, a shoulder or flange, and an 
outwardly projecting female coupling nipple similar to the coupling nipple 
formed on the opposite end of the main body of the valve. When installed 
in the end of the main body, the plug is sealingly received within the end 
of the interior tube so that the tube passageway is continued through the 
end cap and through the coupling nipple to define a continuous passageway 
through the valve. The shoulder or flange of the valve abuts and is sealed 
about the end of the outer shell of the main body to close off the 
pressure chamber defined between the outer shell and the interior tube. 
In use, the valve assembly of this invention functions in much the same way 
as prior art sphincter valves. Specifically, the valve is spliced in a 
fluid flow line by coupling one section of the line to the coupling nipple 
on one end of the valve and coupling the other section of the line to the 
coupling nipple on the opposite end of the valve. Thus, fluid is free to 
flow through the central passageway of the valve. An air pressure supply 
tube is coupled to the coupling nipple projecting from the main body for 
selective delivery of pressurized air to the pressure chamber. 
With no pressurized air supplied to the pressure chamber, fluid is free to 
flow through the valve unimpeded. In this condition, the valve is open. 
When it is desired to close the valve, pressurized air is supplied to the 
pressure chamber. As the air enters the chamber, it exerts inward force on 
the interior tube causing it to collapse on itself closing off 
communication through the valve and shutting off the flow of fluid. Thus, 
the valve can be opened and closed by selectively supplying pressurized 
air to and releasing the pressure from the pressure chamber of the valve. 
In practice, the valve can be cycled in this way up to several times per 
second if desired. 
It has been found that the valve of this invention, in addition simply to 
opening and closing, provides an added function that is particularly 
benificial in colonic lavage applications. Specifically, as pressurized 
air is supplied to the pressure chamber, the interior tube first collapses 
at its center and continues to collapse toward the ends of the valve as it 
closes. This acts to squeeze the fluid within the passageway out of the 
valve causing a short pulse of fluid through the fluid flow line. When the 
valve is cycled rapidly, the result is a pulsating flow of fluid, which, 
when the valve is used in the fluid supply line of a colonic lavage 
apparatus, acts to loosen and dislodge impacted fecal material in a 
patient's colon. While this pulsing function also occurs with prior art 
hard shell sphincter valves, it has been found that the flexibility of the 
unitary silicone structure of the present invention provides pulsing 
action superior to that of prior art valves. 
Thus, it is an object of this invention to provide a sphincter valve that 
is inexpensive to manufacture relative to prior art valves but that 
functions as well or better. 
Another object of the invention is to provided a sphincter valve that is 
reliable yet economical enough to be discardable after a single use. 
A further object of the invention is to provide a sphincter valve that can 
be assembled quickly and with minimum labor. 
A still further object of the invention is to provide a sphincter valve 
having a soft body that is not uncomfortable to the skin of a patient so 
that it can be laid or rested on a patient's body during use if desired. 
These and other objects, features, and advantages of the present invention 
will become apparent upon review of the detailed description set forth 
below when taken in conjunction with the accompanying drawings, which are 
briefly described as follows.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, wherein like numerals refer to like parts 
throughout the several views, FIG. 1 illustrates in cross-section a 
sphincter valve assembly that embodies principles of the present invention 
in a preferred form. The assembly 11 comprises two components, a main body 
12 and an end cap 13. Both the main body 12 and the end cap 13 preferably 
are molded at the same time and in a common mold. Further, both components 
in the preferred embodiment are formed of a flexible somewhat rubber like 
material such as, for example, a silicone, a silicone rubber compound, or 
another synthetic rubber material. Latex materials can also be used, but 
they are not preferred for applications where the valve is likely to come 
into contact with a patient's skin because many patients have latex 
allergies. In any event, the material can be uncolored or pigmented if 
desired and preferably is translucent or partially transparent so that a 
user can observe the operation of and fluid flow through the valve. 
The main body 12 is formed to define a generally cylindrical outer shell 17 
that surrounds and is coaxially aligned with a smaller interior tube 18. 
The outer shell 17 is molded to have relatively thick walls so that it is 
substantially rigid, although some flexibility is provided in the outer 
shell because of the flexible nature of the silicone material from which 
it is molded. Conversely, the walls of the interior tube are relatively 
thin compared to those of the outer shell so that the interior tube is 
flexible and can be collapsed upon itself under the influence of 
appropriate inward force applied to the outside of the tube. The interior 
tube 18 is spaced from the inner walls of the outer shell 17 so that an 
annular or cylindrical pressure chamber 21 is defined between the outer 
shell and the interior tube. 
The main body 12 is also formed with an end portion 14 that is integrally 
molded with the outer shell and the interior tube and from which they 
extend. The end portion 14 is molded with a shoulder 15 from which a 
female coupling nipple 16 axially extends. The end portion closes off the 
pressure chamber at the end of the valve and supports the end of the 
interior tube 18 relative to the outer shell 17. The central passageway 19 
of the interior tube 18 extends continuously through the end portion 14 of 
the main body and axially through the coupling nipple 16 to define a 
continuous uninterrupted passage through the valve. At the other end of 
the main body 12, the outer shell 17 terminates in an end 24 and the 
interior tube 18 terminates in an end 26. In the preferred embodiment, the 
ends 24 and 26 and substantially coplaner; however, this is not a 
requirement and one of the ends could well be recessed with respect to the 
other end. 
The end cap 13 is formed with a central axially extending passageway 27 
that preferably has the same diameter as the central passageway 19 defined 
through the main body 12. The end cap 13 is also formed with a radially 
extending flange 31, an inwardly extending plug 28, and an outwardly 
extending coupling nipple 29. The flange 31 defines a shoulder 32 that is 
sized and configured to abut the end 24 of the outer shell 17 when the end 
cap 13 is installed in the end of the main body as described in more 
detail below. 
The outside diameter of the inwardly extending plug 28 is larger than the 
inside diameter of the central passageway 19 of the interior tube and 
preferably is substantially the same as the inner diameter of the pressure 
chamber 21. With this configuration, the end 26 of the interior tube 18 
and the end 24 of the pressure chamber can be stretched to a larger 
diameter with an appropriate stretching tool and the inwardly extending 
plug 28 can be inserted into the stretched ends as the end cap is 
installed. When the stretched ends are released, they tend to return to 
their original size thereby closing and sealing around the outside of the 
plug 28. More specifically, the end 24 of the pressure chamber, when 
released, closes around the plug 28 and around the tube 18 capturing the 
end 26 of the tube between the plug and the interior wall of the pressure 
chamber. This securely fixes the end of the tube and forms a continuous 
sealed passageway completely through the valve from the left coupling 
nipple 16, through the interior tube 18, and out the right coupling nipple 
29. It is also preferable when installing the end cap that a bead of 
silicone adhesive be applied between the end 24 of the outer shell 17 and 
the shoulder 32 of the end cap. In this way, the pressure chamber 21 is 
reliably sealed against any leakage between the end of the main body 12 
and the end cap 13. 
A female coupling nipple 22 projects radially outwardly from the outer 
shell 17 and has a central passageway 23 that communicates with the 
pressure chamber 21. As described below, the nipple 22 is adapted to be 
coupled to a pressurized air hose for the selective delivery of 
pressurized air to the pressure chamber 21. 
FIG. 2 illustrates the sphincter valve of this invention fully assembled 
and spliced into a fluid delivery line for controlling the flow of fluid 
therethrough. In FIG. 2, the valve is shown in its open condition allowing 
fluid to flow through the valve and through the fluid delivery line. The 
end cap 13 is seen inserted in the end of the main body 12 with the end of 
the interior tube 28 and the end of the pressure chamber stretched and 
sealed about the inwardly projecting plug 28. The shoulder is sealed 
against the end of the outer shell with an appropriate silicone adhesive 
to seal off the end of the pressure chamber 21. 
One end 33 of the fluid delivery line is coupled to the coupling nipple 16 
at the left end of the valve by means of a cylindrical adapter 36. 
Specifically, the adapter 34 fits tightly within both the end of the 
coupling nipple and the end of the delivery tube to couple the two 
together. Other coupling means can also be used. For example, the coupling 
nipple might simple be stretched, the end of the fluid delivery tube 
inserted, and the nipple released to constrict and seal about the end of 
the tube. These and other means of coupling the delivery tube to the valve 
are contemplated and are within the scope of the present invention. 
Similarly, the other end 34 of the fluid delivery line is coupled via 
adapter 37 to the coupling nipple 29 at the other end of the valve. Again, 
while an adapter is used, other coupling means might be employed. Thus it 
is seen that the flow of fluid is free to continue from the left portion 
of the fluid delivery line, through the interior tube of the valve, and 
into the right portion of the fluid delivery line as if the valve were not 
in the system. A pressurized air supply line 39 is coupled to the coupling 
nipple 22 and communicates with the pressure chamber 21 within the valve. 
Through the supply line 39, pressurized air can be selectively injected 
into the pressure chamber for closing the valve as described in more 
detail below. In FIG. 2, no pressure has been applied to the pressure 
chamber and the valve is fully open allowing the free flow of fluid as 
indicated by arrows 38. 
It will be appreciated from FIG. 2 that the flexible nature of the silicone 
material from which the valve is molded contributes to its functionality, 
allowing quick and easy coupling of the valve to the various tubes of the 
fluid delivery and pneumatic control systems. This represents and 
advantage over prior art sphincter valves with hard plastic shells, 
wherein the various tubes and supply lines must generally be coupled to 
the valve with ancillary clamps or other appropriate fastners. 
FIG. 3 illustrates operation of the sphincter valve of this invention to 
close off a flow of fluid and to provide a momentary pulse of fluid 
through the fluid delivery line. As in FIG. 2, the valve 11 is seen to be 
spliced into a fluid delivery line at the opposed ends of the valve. The 
pressurized air supply line 39 is coupled to the main body 12 at the 
coupling nipple 22 and is in communication with the pressure chamber 21 
for delivery of pressurized air thereto. In FIG. 3, pressurized air, or 
other appropriate gas as desired, is shown at 41 being forced into the 
pressure chamber 21 through the pressurized air supply line 39. The 
pressurized air can originate from any appropriate source connected to the 
other end of the supply line 39 (not shown), such as, for example, a pump 
or pressurized air tank and associated control system, a hand operated 
pump, or other source. The actual means of delivering pressurized air to 
the pressure chamber can vary widely depending upon the particular 
application to which the valve is put. 
As pressurized air is delivered to the pressure chamber 21, the pressure 
within the chamber gradually increases as a function of the rate of 
pressurized air flow. This, in turn, exerts increasing inward force on the 
interior tube 18 and corresponding outward force on the interior walls of 
the outer shell 17. Since the walls of the interior tube are substantially 
thinner than the walls of the main body, the increasing force causes the 
interior tube to begin to collapse upon itself. Eventually, the force 
becomes sufficient to cause the walls of the interior tube 18 to meet and 
contact each other intermediate the ends of the tube as illustrated at 46 
in FIG. 3. At this point, the flow of fluid through the fluid delivery 
line is shut off and the valve is in its closed condition. 
If desired, pressurized air can continue to be forced into the pressure 
chamber 21 after the initial closing of the valve. This further increases 
the pressure within the pressure chamber 21 causing the interior tube 18 
to collapse further upon itself from its mid-portion toward its opposed 
ends, as illustrated in phantom lines at 43 in FIG. 3. This action, in 
turn, squeezes out fluid within the interior tube causing a surge or pulse 
of fluid through the fluid delivery line as indicated at 42 in FIG. 3. It 
has been found that the flexible unitary nature of the entire valve 
assembly, including the walls of the main body, improves the efficiency of 
this process as the main body walls bulge slightly outwardly in response 
to the increasing pressure. 
The pulse action of the sphincter valve of this invention provides 
significant advantages in many applications, and particularly in colonic 
lavage procedures. In such procedures, the valve can be opened and closed 
rapidly up to several times per second if desired. This causes a 
distinctly pulsed flow of fluid into a patient's colon as a result of the 
surge or pulsed action provided by the opening and closing valve. Such a 
pulsed flow has been found to be very beneficial in colonic lavage 
procedures for dislodging and hydrating impacted fecal material in a 
patient's colon so that the material can be removed from the colon through 
an associated drain line. Thus, the unique sphincter valve of the present 
invention provides benefits and advantages and does so at a cost and with 
a complexity far less than prior art sphincter valves. Thus, the valve can 
simply be discarded after use, making it ideal for disposable fluid 
delivery kits for use in medical procedures. Disposability is important in 
many medical procedures and particularly procedures such as colonic lavage 
performed at home because the valves become contaminated after use and 
cannot easily be cleaned. Further, the valve of this invention is 
relatively soft and is not uncomfortable to the skin of a patient. It can 
thus be rested on a patient's skin during a procedure if necessary without 
being uncomfortable. 
The invention has been described herein in terms of preferred embodiments 
and methodologies. It will be apparent to those of skill in the art, 
however, that various modifications might well be made to the illustrated 
embodiments within the scope of the invention. For example, while silicone 
or a silicone compound has been illustrated as the preferred material from 
which the valve is molded, other appropriate materials might well be 
substituted. Further, the size and relative dimensions of the various 
components of the valve might be different from those illustrated in the 
drawings depending upon the particular purpose for which it is intended. 
For example, the valve could be made long and thin in order to increase 
the relative length of the interior tube and provide a more pronounced 
pulsed action as the valve is closed. Finally, the sphincter valve of this 
invention has been illustrated and described as a pneumatically controlled 
device wherein air or gas is used to open and closed the valve. In certain 
applications, however, it might be desirable to employ a fluid to open and 
close the valve rather than air. In such cases, the valve would be 
hydraulically controlled rather than pneumatically controlled, but the 
principles of operation would remain substantially the same. Finally, the 
invention has been described in terms of a single unitarily molded valve. 
The same principles could be applied to a unitarily molded gang valve 
wherein two or more individually controllable valves are molded within a 
single unitary body. These and other additions, deletions, and 
modifications might well be made to the disclosed embodiments by those of 
skill in the art without departing from the spirit and scope of the 
invention as set forth in the claims.