Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
COLOSTOMY APPLIANCF AND PRESSURE RELIEF
VALVE ~HEREFOR
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This invention relates to a colostomy appliance, and
to a pressure relief valve therefor.
One of the perennial problems faced by colostomists
is the distension of their stoma bags by flatus. A fully
inflated stoma bag is cumbersome and uncomfortable, and for
many years the only solution to this problem has been to
pierce the inflated bag with a pin, vent the gas, and then
re-seal the bag with a piece of adhesive tape. ~his
procedure is both inconvenient and unnecèssarily awkward,
especially for the older arthritic patient.
Over the last two or three years this situation has
been improved somewhat by the introduction of the flatus
filter. This device takes the form of a small vent in the
stoma bag which is covered by a material with deodourizing
properties, e.g. activated charcoal. Flatus passes freely
through this vent, without causing odour problems, and thus
does not inflate the bag to any large degree. The main
problem with this device is that the permanently open vent
allows a completely uncontrolled passage of flatus and
therefore the bag becomes completely deflated. When this
happens the front wall of the bag may stick to the stoma, and
any faecal matter which passes cannot fall to the bottom of
the bag and clogs the bag around the stoma. This can lead
to faecal leakage between the body and the adhesive.
As a result of this problem, many patients immobilize
the filter by sticking a piece of impermeable adhesive tape
over it. They then achieve a degree of continence of
flatus in that they choose when to remove the tape and allow
flatus to vent. However, in order to carry out this
operation, it is necessary for the patient to be in private
because he has first to loosen or remove clothing. This
is a severe disadvantage because it is when the patient is
in company that the distension of the bag is a particular
problem.
U.S. Patent Specification No. 4,120,715 discloses a
method of making a filter for use in venting a colostomy or
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ileostomy bag.
U.S. Patent Specification No. 3,865,109 discloses
a colostomy attachment employing a faecal pouch with
self venting means for trapped gases.
U.S. Patent Specification No. 3,216,420 discloses
a colostomy attachment comprising a colostomy bag provided
with normally closed manually openable valve means for
release of trapped gases.
U.S. Patent Specification No. 4,232,672 discloses
an ostomy bag connected to a coupling member which includes
valves for controlling exit of gases, said valves being
operated by means of a push button.
The present invention provides a colostomy appliance
comprising a stoma bag having a vent outlet provided
with a pressure relief valve adapted to open when a pre-
determined gas pressure is reached in said bag, said
vent outleL being associated with a deodourizing filter
through which gas is vented from said bag.
The maximum pressure at which the pressure relief
valve opens must be less than the bursting pressure of
the stoma bag, and the minimum pressure should be sufficient
to ensure sufficient inflation of the bag to prevent
collapse of the bag onto the stoma. Preferably the pres-
sure relief valve is adapted to open at relatively low
pressures, e.g., 0.15 to 0.8 p.s.i.g., preferably 0.3
to 0.65 p.s.i.g.
The pressure relief valve preferably comprises
a diaphragm valve member normally sealingly seated against
a valve seat and arranged to lift therefrom when the
predetermined gas pressure is reached in the stoma bag.
According to a preferred aspect of the present
invention there is provided a colostomy appliance compris-
ing a stoma bag having a vent outlet provided with a
pressure relief valve adapted to open when a predetermined
gas pressure is reached in said bag, said vent outlet
being associated with a deodouri7ing filter through which
gas is vented from said bag, said pressure relief valve
comprising a valve housing, at least one inlet port to
said housing, at least one outlet port from said housing,
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a diaphragm valve member sealing said inlet port(s),
and a valve seat against which said valve member is urged
in fluid-tight contact, said valve member being adapted
to lift from said valve seat to open said valve when
said valve is subjected to said predetermined gas pressure.
Optionally the valve housing is formed in two parts
which, when fitted together, prDvide clamping means for
securing the valve in said vent outlet. For example, said
parts comprise inner and outer cylindrical walls received
one within the other, each of said walls having a peripheral
flange at its base for clamping therebetween the margin of
the stoma bag wall surrounding said vent outlet.
Although pressure relief valves comprising a diaphragm
valve member have been referred to above, pressure relief
valves of alternative construction may be employed if desired.
Preferably the pressure relief valve is so profiled
and positioned relative to the stoma bag as to avoid being
snagged and rendered inoperative by clothing.
The deodourizing filter preferably comprises carbon
cloth as described, for example, in British Patent
Specification No. 1,301,101. Alternativ l~ it may, for
example, comprise activated carbon granules. The
deodourizing filter may, for example, be secured to the
pressure relief valve. Alternatively it may be secured to
2û the bag, e.g. across the vent outlet.
A preferred colostomy appliance in accordance with
the present invention, and some preferred pressure relief
valves therefor, will now be described, by way of example,
with reference to the accompanying diagrammatic Drawings,
in which:
Figure 1 is a cross-section through the colostomy
appliance;
Figure 2 is a cross-section through one pressure
relief valve, separated into its two parts, for use in the
3D appliance of Figure 1;
Figure 3 is a plan view of the valve of Figure 2;
Figure 4 is a cross-section through an alternative
pressure relief valve for use in the appliance of Figure 1;
Figure 5 is a cross-section through a second
alternative pressure relief valve for use in the appliance
of Figure 1;
Figure 6 is a cross-section through a third
alternative pressure relief valve for use in the appliance
of Figure 1; and
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Figure 7 is a plan view of the valve of Figure 6.
In the Drawings, like reference numerals indicate the
same or similar parts.
Referring to Figure 1 of the Drawings, the colostomy
appliance comprises a stoma bag indicated generally at 1
having a v0nt outlet 2 provided with a pressure relief valve
3 adapted to open when a predetermined gas pressure is
reached in the bag 1, as more fully described hereinafter,
the vent outlet 2 being associated with a deodourizing filter
4 through which gas is vented from the bag 1.
The bag 1 is disposable, and comprises two plies of
odour-resistant plastics film, e.g. a polyvinyl chloride
(pvc) film sold under the Trade Mark VELBEX EA 265, forming
front and back walls 5, 6 respectively, welded together at
their edges 7 as by radio-frequency welding. The wall 6
has a circular opening 8 surrounded by a circular flange 9
of pvc film welded to the ply 6, the flange 9 being provided
with a layer 10 of contact adhesive for securing the stoma
bag to the stoma opening of the patient. The layer 10 of
adhesive is protected, prior to u~e, by a peelable cover
sheet 11.
e.g.
A sheet 12 of/soft nonwoven fabric is secured to the
lower part of wall 6, which rests against the patient's
body in use, to minimise discomfort.
- The pressure relief valve 3 is shown in Figures 2 and
3. The valve 3 comprises a cylindrical valve housing 13
formed of two parts 14, 15 (shown separate in Figure 2)
injection-moulded from plastics material. These parts are
fitted together, and at the same time secured to bag wall
6, to provide a fluid-tight seal of the vent outlet 2.
The marginal portion 16 of the wall 6 surrounding the
vent outlet 2 is clamped in fluid-tight manner between
clamping jaws constituted by circular flanges 17, 18 provided
at the base of circular walls 197 20 respectively of parts
14, 15. The wall 20 is inserted through the vent outlet 2
from within the bag 1 and received within the circular wall
19. A peripheral bead 21 on wall 20 snap-fits within a
corresponding recess 22 in wall 19. Likewise a peripheral
bead 23 on flange 18 snap-fits within a corresponding recess
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24 in.flange 17, the portiDn 16 being defDrmed in the region
of the snap-fit. The use of such a valve obviates the
necessity of welding the valve to the stoma bag and thereby
simplifies manufacture of the bag, which is a significant
advantage.
The valve 3 further comprises a bowed circular
flexible diaphragm valve member 25. The diaphragm 25 may
be of rubber for example. Diaphragm 25 is supported by a
valve support constituted by a frusto-conical member 26
integral with wall 20 and apertured to provide inlet ports
27 into the valve housing 13. When the outer marginal
portion 28 of diaphragm 25 is lifted from a valve seat
constituted by a circular knife edge 29, integral with
support 26, on which said portion 28 is normally sealingly
seated, entry of gas into housing 13 is afforded. The
diaphragm 25 is apertured at its centre and is fitted over
a peg 30 upstanding from the support 26.
- The peg 20 is push-fitted intD a corresponding socket
31 depending from end-wall 32 of part 14 when parts 14 and
15 are fitted together, thereby clamping diaphragm 25 to
support 26. End-wall 32 is apertured to provide outlet
ports 33 from the valve housing 13. The valve housing is
less than one inch in diameter and about 0.15 inch in depth.
The valve housing may be a single piece rather than
formed of two parts, and may be secured to bag wall 6 by
welding, or an adhesive, for example.
Secured within the housing 14 is a circular layer of
e.g. carbon cloth or nonwoven cloth impregnated with
activated charcoal, constituting the deodDurizing filter 4
through which gas is vented from the stoma bag 1. If
desired, the deodourizing filter 4 may be secured over outlet
ports 33 or inlet ports 27, as by double-sided porous
adhesive tape.
It will be appreciated that gas entering the bag 1
through the opening 5 can be vented from the bag through
vent outlet 2 only when the gas pressure in the bag 1 is
sufficient to lift the diaphragm 25 frorn its valve seat 29~
Because Df its bowed shape, the diaphragm 25 is tensioned and
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urged into fluid-tight contact with valve seat 29.
The pressure relief valve 3 must open before the
stoma bag 1 is unduly distended which causes discomfort
and may lead to rupture. HDwever sufficient inflatiDn of
the stoma bag 1 shDuld be permitted tD prevent collapse of
the bag 1 onto the stoma~ We have found relatively low
pressures, e.g. D.15 to 0.8 p.s.i.g., preferably 0.3 to
0.65 p.s.i.g., to be suitable.
If the patient so desires, he may cause the bag 1
to vent at any time by exerting manual pressure on it.
Accordingly, the release pressure may be such that normally
the bag would not reach it, so that slight external pressure
on the bag would always be required to cause it to open.
This external pressure could be applied by the colostomist
at any time to provide a more convenient form of control
than that currently available, the deodourizing filter
preventing the omission of disagreeable odours at all times
so that the operation can be carried out even in company.
The pressure relief valve 3 is so small and so
positioned as not to be interfered with by the clothing of
the patient and rendered inoperative. A suitable location
is as shown in Figure 1, namely in an upper part of rear
wall 6.
Other pressure relief valves may be used in the stoma
bag 1 as shown in Figures 4 to 7. The pressure relief
valve shown in Figure 4 comprises a cylindrical one-piece
valve housing 34 open at one end and having a peripheral
flange 35 at that end for securing it, by welding or by an
adhesive for example, to the inner wall 6 of the stoma bag 1.
A rigid diaphragm valve member 36 is urged by a coiled
spring 37 against a valve seat constituted by aninternal
flange 38 integral with the housing 34, the top end of the
spring 37 bearing against an end wall 3g of the valve
housing 34. The end wall 39 is apertured to provide outlet
ports 40. In this embodiment the charcoal cloth filter 4
is secured over the vent outlet 2 to the marginal portiDn
16 of the bag wall 6.
The pressure relief valve of Figure 5 is adjustable ?
that is to say the valve can be adjusted to open at
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different pressures. An A'len screw 41 is used to urge a
flexible diaphragm valve member 42, e.g. of plastics material,
against a valve seat 43. By screwing the Allen scr~w 41
into the valve housing 44, the desired degree of bow is
imparted to the diaphragm valve member 42, and the desired
`pressure required in the stoma bag 1 to open the valve is
achieved. A similar pressure relief valve may be employed
in which a fixed stud is used instead of the Allen screw.
Such a valve is not adjustable.
The valve of Figures 6 and 7 comprises a rigid
diaphragm valve member 45. The valve housing 46 is
provided with four downwardly pointing fingers 47 which flex
under pressure to allow the diaphragm valve member 45 to lift
from a valve seat 48. Alternatively, a flexible diaphragm
valve member and stiff fingers could be used.
We believe the pressure relief valves of Figures 2 to
7 to be novel, and accordingly the present invention further
provides a pressure relief valve comprising a valve housing,
at least one inlet port to said housing, at least one outlet
port from said housing, a diaphragm valve member sealing said
inlet port(s), and a valve seat against which said valve
member is urged in fluid-tight contact, said valve member
being adapted to lift from said valve seat to open said valve
when said valve is subjected to a predetermined fluid
pressure.
Optionally said valve housing is formed in two parts
which, when fitted together, provide clamping means for
securing the valve in an aperture. For example, said parts
of said housing comprise inner and outer cylindrical walls
received one within the other, each of said walls having a
peripheral flange at its base to constitute said clamping
means.
In one embodiment, the diaphragm valve member is
fle~ible. Means may be provided for urging said diaphragm
valve member into fluid-tight contact with the valve seat,
the means being adjustable to set the pressure at which the
valve is opened. The valve seat may be constituted by a
knife edge. Means may be provided for clamping the
diaphragm valve member to a valve support.
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The valve housing may be cylindrical and the valve
support is, e.g. a frusto-conical member secured within the
valve housing and apertured to define the inlet port(s).
The present invention even further provides a
colostomy bag or ileostomy bag having a vent outlet provided
with a pressure relief valve as set forth in the immediately
foregoing four paragraphs. Preferably the bag further
comprises a deodourizing filter associated with the vent
outlet, especially when the bag is a colostomy bag.
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