A DISPOSABLE MOUTHPIECE

This invention relates to a one way valve for a disposable mouthpiece and, more especially, this invention relates to a one way valve for a disposable mouthpiece used by a person to exhale into a respiratory instrument.

Persons are often required to exhale into different types of respiratory instruments in order to indicate the state of health of different parts of the persons, for example their lungs. The various respiratory instruments are expensive and each respiratory instrument has to be used by many different persons. In order to avoid the mouths of the different persons contacting the same respiratory instrument, it is known to use disposable mouthpieces. Initially, the disposable mouthpieces were usually simple tubes, for example cardboard tubes. In use, one end of the disposable mouthpiece was connected to the respiratory instrument, and a person blew into the other end of the disposable mouthpiece. After use, the disposable mouthpiece was disposed of. The respiratory instrument was not been contacted by the mouth of the person blowing into the respiratory instrument, and so the respiratory instrument was immediately ready for use by another person.

As levels of hygiene increased, it has become the custom to incorporate a one way valve in the disposable mouthpieces. This is because the respiratory instrument may become infected as persons blow into it. If a

person inhales whilst their mouth is still connected to the respiratory instrument via the disposable mouthpiece, then it is possible that any infection in the respiratory instrument could be inhaled by the person. The presence of the one way valve in the disposable mouthpiece helps to avoid this possibility of cross contamination between persons, for example patients in a hospital or in a doctor's surgery.

The known one way valves for disposable mouthpieces each comprise a body, a through bore in the body, and a valve member which extends across the through bore. The valve member is flexible and it is arranged such that it bends when the person exhales. This allows the passage of the exhaled air from the person and into the respiratory instrument. The valve member is also such that it seals when the person inhales. This prevents the passage of the inhaled air into the person, and thereby prevents the person becoming infected with any infection that may be in the respiratory instrument as a result of the respiratory instrument having previously being used by another person and who had an infection. The known one way valve is such that the valve member is secured to the valve body at a central portion of the valve member. The valve member bends about the central portion when the person exhales. The central portion of the valve member does not move and it is centrally located in the through bore. This central portion of the valve member forms a substantial resistance to the passage of the exhaled air. There are occasions when problems can arise as a result of the resistance caused by the central portion of the valve member to the flow of exhaled air from the person. The

resistance may be such that the expiratory flow rate may be affected so that an incorrect measurement is made.

It is an aim of the present invention to obviate or reduce the above mentioned problem.

Accordingly, in one non-limiting embodiment of the present invention there is provided a one way valve for a disposable mouthpiece used by a person to exhale into a respiratory instrument, the one way valve comprising a body, a through bore in the body, and a valve member which extends across the through bore, the valve member being flexible and arranged such that it bends when the person exhales in order to allow the passage of the exhaled air from the person into the respiratory instrument and such that it seals when the person inhales in order to prevent the passage of inhaled air from the respiratory instrument into the person and thereby to prevent the person becoming infected with any infection that may be in the respiratory instrument as a result of the respiratory instrument having previously been used by a person who had an infection, characterised in that the valve member is secured to the valve body at a peripheral portion of the valve member and the valve member bends about the peripheral portion when the person exhales.

With the one way valve of the present invention, the valve member bends about the peripheral portion. Thus substantially the entire valve member is able to bend away from its blocking position in the through bore when the person blows into the disposable mouthpiece. This ensures that the valve member provides a much reduced resistance to the exhaled air, as

compared with the above mentioned known valve member in the known one way valve.

The peripheral portion of the valve member may be a tab. Other shapes for the peripheral portion may be employed.

When the peripheral portion of the valve member is a tab, then the valve member may comprise a slot which is positioned adjacent the periphery of the valve member and which extends parallel to the periphery of the valve member for the entire periphery of the valve member except for the width of the tab, whereby the slot forms the tab and also forms a peripheral margin which is available for securing the valve member in position. Advantageously, the body has a lip which extends through the slot in the valve member and which thereby locates the valve member in the body.

The one way valve of the present invention may include abutment means against which the valve member seals on inhalation by the person. Preferably, the abutment means includes a plurality of abutment members extending inwardly with respect to an abutment ring formation.

The valve member will usually be circular in plan so that it will be in the form of a thin disc. The valve member may be of other shapes in plan if desired.

The present invention also extends to a disposable mouthpiece when including the one way valve.

The body is preferably a push fit over an end of the disposable mouthpiece. The body may have a flange for locating and retaining the

body on the disposable mouthpiece. Unusually, a person using the disposable mouthpiece will have their mouth in contact with the one way valve.

Usually, the disposable mouthpiece will be a tube, and the body will be a tubular body. Other shapes may however be employed. The tube may be made of cardboard, and the one way valve may be made of a plastics material. Other materials may be used if desired.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:

Figure 1 shows a known disposable mouthpiece with a one way valve, and in use by a person exhaling into a respiratory instrument;

Figure 2 is a partially cut-away view of the one way valve shown in Figure 1 and with a valve member in its sealed condition;

Figure 3 is a partially cut-away view like Figure 2 but shows the valve member in its non-sealing condition;

Figure 4 is an exploded view of a valve member of the present invention for a disposable mouthpiece used by a person to exhale into a respiratory instrument;

Figure 5 is a partially cut-away view like Figure 2 but shows the valve of Figure 4; and

Figure 6 is a partially cut-away view like Figure 3 but shows the valve of Figure 4.

Referring to Figures 1 , 2 and 3 there is shown a one way valve 2 for a disposable mouthpiece 4 used by a person 5 to exhale into a respiratory

instrument 6. The one way valve 2 comprises a body 8, a through bore 10 in the body 8, and a valve member 12 which extends across the through bore 10. The valve member 12 is flexible. The valve member 12 is arranged such that it bends as shown in Figure 2 when the person 5 exhales in order to allow the passage of exhaled air into the respiratory instrument 6. The valve member 12 is such that it seals as shown in Figure 1 when the person 5 inhales in order to prevent the passage of the inhaled air into the person 5, and thereby to prevent the person 5 becoming infected with any infection that may be in the respiratory instrument 6 as a result of the respiratory instrument 6 having previously been used by other persons.

The valve member 12 is secured to the valve body 8 at a central portion 14 of the valve member. More specifically, the central portion 14 includes an aperture 16 which locates over a longitudinally extending spigot 18 formed as part of the body 8. The spigot 18 is held in position by three arms 20 extending inwardly from an outer wall 22 of the body 8.

When person 5 exhales, the outer portion 24 of the valve member 12 bends under the action of the exhaled air, as shown in Figure 3. The central portion 14 remains stationary because it is secured to the spigot 18. Thus the central portion 14 forms a large area causing an appreciable resistance to the exhaled air.

The respiratory instrument 6 is connected by a lead 15 to an instrument 17 which is able to give a visual display 19 on a screen 21 , and also a hard copy print out 23 from a printer 25. The respiratory instrument 6 may be, for example, a flow transducer.

Referring now to Figures 4 and 5, there is shown a one way valve 26 which overcomes the problems mentioned above with regard to the one way valve 2. More specifically, the one way valve 26 is for a disposable mouthpiece 28 which may be used by the person 5 to exhale into the respiratory instrument 6 shown in Figure 3. The one way valve 26 comprises a body 32, a through bore 34 in the body 32, and a valve member 36 which extends across the through bore 34.

The valve member 36 is flexible. The valve member 36 is arranged such that it bends as shown in Figure 5 when the person exhales in order to allow the passage of the exhaled air into the respiratory instrument 6. The valve member 36 is also such that it seals as shown in Figure 4 when the person 5 inhales in order to prevent the passage of the inhaled air into the person 5. This then prevents the person becoming infected with any infection that may be in the respiratory instrument 30 as a result of the respiratory instrument 30 having previously been used by another person who had an infection.

The valve member 36 is secured to the valve body 32 at a peripheral portion in the form of a tab 38. The valve member 36 bends about the tab 38 when the person exhales.

The valve member 36 comprises a slot 40 which is positioned adjacent the periphery 42 of the valve member 36 and which extends parallel to the periphery 42 of the valve member 36 for the entire periphery 42 of the valve member 36 except for the width of the tab 38. Thus the slot 40 forms the tab 38. The slot 40 also forms a peripheral margin 44 which is

available for securing the valve member 36 in position. More specifically and as shown in Figure 4, the body 32 has a lip 46. The lip 46 extends through the slot 40 in the valve member 36 and thereby locates the valve member 36 in the body 32.

The body 32 includes abutment means in the form of a plurality of abutment members 48 which extend inwardly with respect to a ring formation 50. As can be appreciated from Figures 5 and 6, the valve member 36 abuts against these abutment members 48 when the person 5 inhales. The abutment members 48 ensure that the valve member 36 does not collapse on inhalation and thus ensures that the valve member 36 seals the through bore 34 on inhalation by the person 5. Thus cross- contamination from the respiratory instrument 6 is prevented.

The valve member 36 is circular in plan. As shown in Figures 4, 5 and 6, the valve member 36 is in the form of a thin disc which may be regarded as a membrane. The body 32 is a tubular body which pushes into the disposable mouthpiece 28 which is also in the form of a tube. The body 32 has a flange 52 which locates and retains the body 32 in the disposable mouthpiece 28.

It is to be appreciated that the embodiment of the invention describe above with reference to Figures 4, 5 and 6 has been given by way of example only and that modifications may be effected. Thus, for example, the tab 38 and the abutment members 48 may be of different shapes to that shown. The disposable mouthpiece 28 is preferably made of cardboard but it may be made of other materials if desired.