Valve assemblies

A valve assembly comprises a resilient housing of plastic material and a valve element in the form of a unitary plastic body located within the housing. The body is closed at one end by a dish-shape portion having a circumferential lip which forms a seal with the housing. The body has a tongue formed in its wall, one end of the tongue being provided with an inwardly directed tooth. By inserting a tube or rod within the valve element to engage the tooth, the tongue can be displaced outwardly and the overlying part of the housing can thereby be distorted away from the lip to permit fluid flow through the housing. The valve assembly may be used to seal one end of the inflation line of a cuffed medico-surgical tube.

BACKGROUND OF THE INVENTION 
This invention relates to valve assemblies, valve elements for use in such 
assemblies, and medico-surgical tubes including such assemblies. 
The invention is particularly, though not exclusively concerned with valve 
elements and valve assemblies for use in medico-surgical tubes of the kind 
provided with an inflatable cuff around a portion of the tube. In such an 
application, the valve assembly may be provided at one end of a fluid line 
making connection with the interior of the cuff. 
Valve assemblies for use in such medico-surgical tubes are known in which 
the assembly includes a resilient housing having a passageway therethrough 
which is normally blocked by a plug located in the passageway. This known 
form of valve assembly can be opened by inserting within the passageway 
the tip of a syringe which engages with projections formed on the inside 
of the housing and thereby distorts the housing away from the plug to form 
a gas passageway between the plug and the housing. 
While this known form of valve assembly has proved useful on 
medico-surgical tubes, some users of such tubes prefer not to use valves 
but instead to close the fluid line to the cuffs by means of a stopper or 
similar device. It has therefore, until now, been necessary either to 
manufacture two ranges of medico-surgical tubes, one with valves and one 
without valves, or to rely on the user himself making somewhat difficult 
and unreliable adaptations of a tube provided with a valve, according to 
his preferred method of use. 
BRIEF SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a valve assembly, a 
valve element for such an assembly and a medico-surgical tube including 
such as assembly that can be manufactured cheaply and that can be used to 
alleviate the above disadvantage. 
According to one aspect of the present invention there is provided a valve 
assembly including a resilient housing, a unitary body located within said 
housing, said body being adapted for sealing engagement within said 
housing so as thereby to prevent fluid flow through said housing, wherein 
said body is adapted for engagement by an actuating member inserted within 
it, such as thereby to have a part at least of the body displaced 
outwardly by said actuating member and to distort said housing away from 
said body such as to permit fluid flow through said housing. 
According to another aspect of the present invention there is provided a 
valve element comprising a unitary body having a portion for sealing 
engagement within a resilient housing, so as to prevent fluid flow through 
the housing, wherein said body is adapted for engagement by an actuating 
member inserted within it, such as thereby to have a part at least of the 
body displaced outwardly by said actuating member to distort said housing 
away from said sealing portion of the body such as to permit fluid flow 
through said housing. 
The body may have an inwardly-directed surface formation adapted for 
engagement by said actuating member. The surface formation may be formed 
at one end of an elongate portion formed in the wall of said body. 
The body of a valve assembly according to the present invention may be 
readily inserted and removed from the housing by the user thereby enabling 
a valve assembly including such a body to be easily modified. 
According to a further aspect of the present invention there is provided a 
medico-surgical tube having a cuff encompassing a portion of the tube 
length and a fluid passageway which connects with the interior of said 
cuff and which is provided at one end with a valve assembly for preventing 
fluid escape from said cuff, wherein said valve assembly includes a 
resilient housing, a unitary body located within said housing, said body 
being adapted for sealing engagement with said housing so as thereby to 
prevent fluid flow through said passageway, and wherein said body is 
adapted for engagement by an actuating element inserted within it, such as 
thereby to have a part at least of the body displaced outwardly by said 
actuating element and to distort said housing away from the body such as 
to permit fluid flow through said housing. 
A valve assembly, a valve element for such an assembly, and a 
medico-surgical tube including such a valve assembly each in accordance 
with the present invention, will now be described, by way of example, with 
reference to the accompanying drawings.

The valve element, as shown in FIGS. 1 and 2, is a unitary moulded body 1 
of acetal plastic and is of a generally cylindrical shape, being hollow 
and open at one end. The body 1 has a radially extending flange 2 at its 
open end and tapers slightly to a reduced diameter at its forward end 
where it is closed by a dished portion 3. A circumferential edge of the 
dished portion 3 projects outwardly of the surface of the body 1 thereby 
forming a lip 4. Rearwardly of the lip 4, a `U`-shaped cut-away portion 5 
is formed in the wall of the body 1 to define a tongue 6 that extends 
along a part of the length of the body. The tongue 6 has at its tip, a 
tooth 7 that projects into the interior of the body 1. 
With reference to FIG. 3, the valve assembly has a tubular polyvinyl 
chloride valve housing 8 formed with a rear portion 9 into which the body 
1 is inserted with its flange 2 abutting the end of the housing. The 
housing 8 also has a forward portion 10 which is of a smaller diameter and 
which connects with the rear portion 9 via an intermediate tapering 
portion 11. A small rim 12 is formed around the circumference of the outer 
surface of the housing 8, between the forward portion 10 and the tapering 
portion 11. The housing 8 is also provided with a stopper 13 formed at the 
end of a flexible tag 14 that is integral with the housing and extends 
outwardly of it at its rear end. The stopper 13 may be used to close the 
housing 8 when the valve body 1 is not in place, by bending the tag 14 and 
inserting the stopper in the rear end of the housing. When the valve body 
1 is in place, it forms a tight fit with the rear portion 9 of the housing 
8, the housing being sufficiently resilient to ensure a fluid-tight seal 
about the lip 4 of the dished portion 3. 
The valve assembly may be `opened`, to allow passage of fluid along the 
housing 8, by distorting the housing away from the dished portion 3 of the 
body 1. This is done by inserting an actuating tube 15 in the rear end of 
the valve body 1 and pushing it forwards of the valve body as shown in 
FIG. 4. The tube 15 has an external diameter that is approximately the 
same as the internal diameter of the valve body 1 so that, as the tube is 
pushed forwards, it engages with the tooth 7 thereby causing the tongue 6 
and the overlying portion of the housing 8 to be displaced outwardly. A 
passageway is thus formed between the housing 8 and the dished portion 3 
to permit the flow of gas or liquid through the cut-away portion 5. When 
the tube 15 is withdrawn, the resilience of the housing 8 urges it firmly 
into contact with the lip 4 of the dished portion 3 to re-seal and `close` 
the valve assembly. The lip 4 also ensures that the valve element is not 
inadvertently pulled out of the housing 8 upon withdrawal of the tube 15. 
With reference to FIG. 5 the valve assembly is illustrated in use with a 
cuffed endotracheal tube 16. The forward portion 10 of the valve assembly 
housing 8 is connected to the end of an air-line 17 which makes connection 
with the interior of a cuff 18 secured around a portion of the 
endotracheal tube 16 at one end. A pilot balloon 19 embraces the forward 
end 10 of the housing 8 and a short portion of the air-line 17, the 
interior of the pilot balloon 19 being in communication with the air-line 
17 so as to be inflated or deflated in accordance with inflation or 
deflation of the cuff 18 and hence give an indication of its condition. 
The cuff 18 is inflated by inserting the nose 20 of a syringe 21 within 
the valve assembly to distort the housing 8 in the manner described above. 
By depressing the plunger of the syringe 20 a measured quantity of air or 
other fluid can be delivered to the cuff 18 to inflate it to the required 
extent; upon removal of the syringe an air-tight seal is formed, 
preventing deflation of the cuff. When it is required to deflate the cuff 
18, the syringe 20, or any other suitably shaped member, can be inserted 
within the valve body 1 to distort the housing 8 away from dished-portion 
3 and thereby allow the retained air to escape. 
One advantage of the form of valve element described is that it may readily 
be inserted in or removed from the housing 8. For this reason, the valve 
housing 8 and body 1 may be supplied to the user in the manner shown in 
FIG. 6, in which the body 1 is attached to the housing by means of the tag 
14 and stopper 13 which is inserted in the open end of the body. Thus, the 
valve body 1 can be pushed into position within the end of the housing 8 
using the stopper 13 and tag 14 to aid insertion, the stopper subsequently 
being pulled out of the body. If preferred, however, the user of such an 
assembly could discard the valve body 1 by removing it from the stopper 13 
prior to use. 
When such a valve assembly is attached to the end of the air-line of a 
cuffed endotracheal tube the user of the tube is able either to use the 
valve assembly in conjunction with the valve body 1, or to effect sealing 
of the air-line 17 by, for example, pinching it closed and inserting the 
stopper 13 in the end of the housing. It is not therefore necessary to 
manufacture two different endotracheal tubes, one with a valve and one 
without, since the same tube can be adapted easily by the user according 
to his preferred method of inflating the cuff. 
It is envisaged that the valve element could be made of material other than 
an acetal plastic, such as, for example, nylon, ABS, polycarbonates, 
stainless-steel or silver. The valve housing 8 could likewise be made of 
any suitable resilient material. 
Although the valve element described has but a single tongue 6 and tooth 7, 
it may be found preferable in some cases to have more than one tongue. 
Other forms of valve element, in addition to the tongue and tooth 
configuration, are also envisaged, for example, instead of having a member 
projecting from the wall of the valve body into its interior, the interior 
could be tapered to a greater extent than is shown in the accompanying 
drawings. It would, in this case, be necessary to use an actuating tube, 
the diameter of which would be sufficiently large, when inserted, to 
distort the wall of the valve body outwardly and cause a gas passage to be 
formed between the housing and the valve element. 
The valve element and the valve assembly are not restricted to use with 
endotracheal tubes but may be used, for example, in pneumatic tyres or 
other articles such as footballs, inflatable life-saving jackets, 
air-mattresses and -pillows.